5th Iberian Meeting on Colloids and Interfaces, RICI5
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5th Iberian Meeting on Colloids and Interfaces, RICI5 Book of Abstracts EDITORS Jacqueline Forcada Josetxo Ramos www.ehu.es
Transcript of 5th Iberian Meeting on Colloids and Interfaces, RICI5
5th Iberian Meeting on Colloids and Interfaces, RICI5
Book of Abstracts
EDITORS Jacqueline Forcada
Josetxo Ramos
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ISBN 978-84-9860-832-8
5th Iberian Meeting on Colloids and Interfaces, RICI5
Book of Abstracts
26-28th June 2013 Donostia-San Sebastián
EDITORS Jacqueline Forcada
Josetxo Ramos
PARTNERS AND SPONSORS
© Servicio Editorial de la Universidad del País Vasco / Euskal Herriko Unibertsitateko Argitalpen Zerbitzua / University of the Basque Country Press
ISBN: 978-84-9860-832-8 / D.L.: BI-835-2013
www.ehu.es/argitalpenak
SCIENTIFIC COMMITTEE
Joan Estelrich University of Barcelona Jacqueline Forcada University of the Basque Country UPV/EHU Ramón González Rubio Complutense University of Madrid Roque Hidalgo-Álvarez University of Granada Issa Katime University of the Basque Country UPV/EHU Luis Liz-Marzán CIC Biomagune Eduardo Marques University of Porto Francisco J. Meseguer Associated Unit ICMM-CSIC/UPV Víctor Mosquera University of Santiago de Compostela Mª Luisa Moyá University of Sevilla Elisabete Oliveira University of Minho Artur Valente University of Coimbra Mercedes Velázquez Salicio University of Salamanca
ORGANIZING COMMITTEE
Jacqueline Forcada (Chairwoman) University of the Basque Country UPV/EHU Josetxo Ramos (Secretary) University of the Basque Country UPV/EHU Isabel Goñi University of the Basque Country UPV/EHU Mariló Gurruchaga University of the Basque Country UPV/EHU Garbiñe Aguirre University of the Basque Country UPV/EHU Aintzane Pikabea University of the Basque Country UPV/EHU Ainara Imaz Navarre Government Óscar Ameneiro University of Vigo
WELCOME to the RICI5 in DONOSTIA-SAN SEBASTIÁN
We are pleased to welcome you to the 5th Iberian Meeting on Colloids and Interfaces,
RICI5. This time the RICI5 is held in the beautiful city of Donostia-San Sebastián in the Basque Country, from 26 to 28 June 2013.
As we will see over the course of the two and a half days of meeting, the diversity and high scientific quality of the contributions of both senior and young Iberian and international researchers will be a testimony of the vivacity of the field of Colloid and Interface Science from synthesis to applications through characterization, modeling, and simulation.
The RICI5 will showcase the latest research and advances in this multidisciplinary field continuing a series of successful Iberian meetings in Salamanca, Coimbra, Granada, and Porto and pursues the objective of also succeed despite the uncertain times we are experiencing in Iberia.
In addition to the oral program, different poster sessions will be run outside the lecture room. Two special posters sessions will take place on Thursday 27 and Friday 28 (each consisting of 1 hour) allowing for showing in 5 minutes 24 posters selected from the presented. In all the contributions the participation of young researchers has priority. This program will give us the opportunity to see the wide range of topics relating to this meeting and to exchange ideas and discuss perspectives in the field. At the same time, you can take a minute to visit the commercial exhibits to see the latest in analytical techniques related to colloids and surfaces.
3 awards for the best oral presentations among young scientists and 2 awards for the best poster presentations will be funded by the ACS journal Langmuir.
2 poster prizes will be given by the Wiley journal Particle. Consisting of a book voucher to the value of 150 € and a 1-year subscription to the journal.
And last but not least, we hope that you will enjoy the social program including the welcome cocktail on Wednesday 26 evening at the Miramar Palace and the conference banquet on Friday 28 evening at the Real Club de Tenis Ondarreta.
Once again, ONGI ETORRIAK to Donostia-San Sebastián! We wish you a successful and enjoyable meeting.
Jacqueline Forcada Luis M. Liz-Marzán Eduardo F. Marques
Chairwoman
Grupo Especializado de Coloides e Interfases de las
Reales Sociedades Españolas de Química y de Física
Grupo de Colóides, Polímeros e Interfaces da Sociedade Portuguesa de Química
PROGRAMME
Wednesday, 26th June 2013 10:00 13:00 REGISTRATION
13:45 13:50 OPENING CEREMONY
13:50 14:35 PL1 Teresa López-León
ESPCI-ParisTech Liquid crystalline superatoms Chair: R. Hidalgo-Álvarez
14:35 14:55 I1 Ralf P. Richter
CIC biomaGUNE Biomolecular hydrogels – nature's playground for supramolecular chemistry and physics
Session 3. SOFT COLLOIDS. SOFT NANOTECHNOLOGY. BIOINSPIRED SYSTEMS
14:55 15:10 O3.1 A. C. N. Oliveira
Univ. Minho Monoolein-based liposomes for siRNA delivery
15:10 15:25 O3.2 J. Morros
IQAC-CSIC The cooperative interaction between hydrophobically modified inulin and DDAB
15:25 15:40 O3.3 M. Homs
IQAC-CSIC Polymeric nano-emulsions obtained by low-energy methods and their use for nanoparticle templating
15:40 15:55 O3.4 R. G. Rubio
Complutense Univ. Madrid Stable capsules formed by liposomes coated by the layer-by-layer method
15:55 16:10 O3.5 S. G. Silva
Univ. Porto Serine-based catanionic liposomes as potential nanocarriers for molecular delivery
16:10 16:25 O3.6 A. Fernández-Barbero
Univ. Almería Soft Particles for Tunable Nanophotonics
16:30 17:00 Coffee Break + POSTERS SESSION 1
17:00 17:20 I2 L. R. Rodrigues
Univ. Minho Biosurfactants: Powerful Tools in Microbial Enhanced Oil Recovery
Chair: J. Estelrich
Session 2. POLYMERS, POLYELECTROLYTES, SURFACTANTS AND GELS
17:20 17:35 O2.1 R. Lund
Univ. Oslo Non-equilibrium Kinetics in Block Copolymer Micelles Observed by millisecond Time-Resolved SAXS and SANS
17:35 17:50 O2.2 J. Sabín
Univ. Santiago Compostela A unique colloidal “crystal-gel” structure observed in microgravity conditions
17:50 18:05 O2.3 J. Miras
IQAC-CSIC pH-response and crosslinking time effect on chitosan nanofilms
18:05 18:20 O2.4 B. Stewart
Univ. Coimbra Molecular Dynamic Simulations of Conjugated Polyelectrolytes with Surfactants in Solvent Environments
18:20 18:35 O2.5 A. Mezei
IQAC-CSIC Nanostructure of cationic surfactant-DNA complexes
18:35 18:50 O2.6 P. Rodríguez-Dafonte
Univ. Santiago Compostela Micellar Shape Transition in an Imidazolium based-surfactant
18:50 19:05 O2.7 M. L. Moyá
Univ. Seville
Binding of cationic single-chain/dimeric surfactants to bovine serum albumin. Influence of the number of hydrophobic chains and the presence of aromatic rings on the protein-surfactant interactions
19:30 21:00 WELCOME COCKTAIL
Thursday, 27th June 2013 08:45 09:30 PL2 Clément Sanchez
Univ. Pierre et Marie Curie Molecular engineering of Inorganic and Hybrid Nanostructured Materials
Chair: L.M. Liz-Marzán
09:30 09:50 I3 Rita S. Dias
NTNU, Trondheim Effect of charge mobility and chain length on the adsorption of poly-acids on oppositely char-ged nanoparticles. A Monte Carlo Simulation
Chair: E.F. Marques
Session 6. MODELING AND SIMULATIONS
09:50 10:05 O6.1 A. Patti
IQAC-CSIC Stochastic diffusion of isotropic and liquid crystal phases of rodlike colloidal particles: Monte Carlo and Brownian Dynamics meet
10:05 10:20 O6.2 M. Quesada-Pérez
Univ. Jaén Coarse-grained Monte Carlo simulations of thermo-responsive polyelectrolyte nanogels
10:20 10:35 O6.3 A. Moncho-Jordá
Univ. Granada Effective electrostatic interactions arising in core-shell charged microgel suspensions with added
10:35 10:50 O6.4 S. C. C. Nunes
Univ. Coimbra Non-random adsorption of polyelectrolytes in regularly charged surfaces. From single chain to multichain deposition
10:50 11:20 Coffee Break + POSTERS SESSION 2
11:20 11:40 I4 Antonio M. Puertas
Univ. Almería The fluctuation theorem in dense colloids: A simulation study
11:40 11:55 O6.5 J. Faraudo
ICMAB-CSIC A molecular insight on new vesicular systems formed by self-assembly of sterols and quaternary ammonium surfactants
11:55 12:10 O6.6 A. Cuetos
Univ. Pablo de Olavide Internal and free energy in a pair of like-charged colloids. Confined and bulk fluids
Session 7. BIOTECHNOLOGICAL APPLICATIONS
12:10 12:25 O7.1 R. Ahijado-Guzmán
Univ. Mainz Multiplexed Plasmon Sensor for Rapid Label-free Analyte Detection
Chair: M.E.C.D.R. Oliveira
12:25 12:40 O7.2 J. P. N. Silva
Univ. Minho Development of DODAB:MO Liposomes for Gene Delivery
12:40 12:55 O7.3 G. Luque-Caballero
Univ. Granada Using AFM to study the complexation of DNA and anionic lipid mediated by Ca2+ at the air-water interface
12:55 13:10 O7.4 A. M. Cardoso
Univ. Coimbra Gene Transfer Mediated by Bis-Quaternary Gemini Surfactants Depends on Complex Architecture
13:10 14:00 Lunch
14:05 14:25 I5 Delfi Bastos-González
Univ. Granada The Ion Specificity on Colloidal Systems Chair: M.M. Velázquez
Session 5. SURFACES AND INTERFACES
14:25 14:40 O5.1 R. Fernandes
Univ. Porto NMR self-diffusion studies on the binding and exchange dynamics between block copolymers and carbon nanotubes
14:40 14:55 O5.2 J. Maldonado-Valderrama
Univ. Granada Probing in-vitro digestion of interfacial protein structures in a single droplet
14:55 15:10 O5.3 J. Benavente
Univ. Málaga Effect of porosity and surface material in the transport of ions across nanoporous alumina membranes
15:10 15:25 O5.4 F. Ortega
Complutense Univ. Madrid Bulk and interfacial Microrheology
15:25 15:40 O5.5 C. L. Moraila-Martínez
Univ. Granada Segregation of silica particles with different size using driven receding contact lines
15:40 15:55 O5.6 C. Drummond
Centre Recherche Paul Pascal Ions-Induced Nanostructuration of Hydrophobic Polymer Surfaces
15.55 16:10 O5.7 T. Alejo
Univ. Salamanca Quantum Dots onto Polymer and Surfactant self-assembled Films: A Quartz Crystal Microbalance Study
16:10 16:25 O5.8 F. Martínez-Pedrero
Complutense Univ. Madrid Sudden Field Induced Sublimation In 2D Colloidal Crystallites
16:30 17:00 Coffee Break + POSTERS SESSION 3
17:00 17:20 I6 Juan A. Anta
Univ. Pablo de Olavide
Electron dynamics in nanostructured metal-oxide films: novel routes towards clean energy technologies
Chair: F.J. Meseguer
Session 4. COLLOIDS AND ENERGY
17:20 17:35 O4.1 J. P. Segovia-Gutiérrez
Univ. Granada A rheological study of magnetic fluids based on highly viscoelastic solvents
17:35 17:50 O4.2 M. A. López-Quintela
Univ. Santiago Compostela Band gap engineering with subnanometric metal (0) clusters: catalytic, electrocatalytic & photocatalytic applications
17:50 18:10 I7 Ana Charas
Inst. Telecomunicações, Lisbon Nanostructured surfaces of conducting polymers and applications in organic photovoltaic cells
18:10 19:05
POSTERS SPECIAL SESSION 1 Chair: M.L. Moyá
PSS01 M. A. Busquets Univ. Barcelona PSS02
M. A. Fernandez-Rodriguez Univ. Granada PSS03 M. C. Neves
Univ. Aveiro
PSS04 L. Polavarapu CICbiomaGUNE PSS05 D. Rodríguez-Fernández
CICbiomaGUNE PSS06 M. Sánchez-Domínguez CIMAV, Mexico
PSS07 S. Vílchez-Maldonado IQAC-CSIC PSS08 T. Costa
Univ. Coimbra PSS09 C. M. G. Duarte Univ. Coimbra
PSS10 A. F. Jorge Univ. Coimbra PSS11 M. Fanun
CSRC, Palestine
19:30 20:30 ASAMBLEA GECI
Friday, 28th June 2013 08:45 09:30 PL3 Tito Trindade
Univ. Aveiro Inorganic nanocrystals as functional building units for composites
Chair: E.F. Marques
09:30 09:50 I8 Hans Heuts
Eindhoven Univ. Technology Functional Hairy Particles and Films via Block Copolymer-Stabilized Emulsion Polymerization
Chair: A. Elaissari
Session 1. NANOPARTICLES: ORGANIC, INORGANIC AND HYBRIDS
09:50 10:05 O1.1 S. Carregal-Romero
Univ. Marburg Light-Addressable and Degradable Silica Capsules for Cytosolic Release
10:05 10:20 O1.2 R. Fenollosa
Univ. Politécnica Valencia Silicon Colloids with a strong magnetic response below 1.5 micrometers region
10:20 10:35 O1.3 S. Fateixa
Univ. Aveiro Resizing of colloidal gold nanorods using aqueous K2S2O8 and morphological probing by SERS
10:35 10:50 O1.4 N. Pazos-Pérez
Univ. Bayreuth Organized plasmonic clusters with high coordination number and extraordinary SERS enhancement
10:50 11:20 Coffee Break + POSTERS SESSION 4
11:20 11:40 I9 Pablo Taboada
Univ. Santiago Compostela Nanosized particles: Beyond a simple tool to fight against disease
Chair: A.J.M. Valente
11:40 11:55 O1.5 A. L. Daniel-Da-Silva
Univ. Aveiro Efficient eco-friendly dye nano-adsorbents based on biopolymer surface functionalized magnetic nanoparticles
11:55 12:10 O1.6 B. Nyström
Univ. Oslo Microfluidic Self-Assembly of Polymeric Nanoparticles in Aqueous Solutions and Controlled Drug Delivery
12:10 12:25 O1.7 D. Jiménez de Aberasturi
Univ. Basque Country New applications modifying colloidal particles with ion-specific ligands
12:25 12:40 O1.8 L. Sacarabelli
CIC biomaGUNE Optimized Synthesis of Gold Nanorods
12:40 12:55 O1.9 B. Martín-García
Univ. Salamanca Shearing as a driven Force to direct the Assembly of Nanocomposites Films
12:55 13:10 O1.10 C. Rey-Castro
Univ. Lleida Dissolution of ZnO nanoparticles in aqueous media: A first essential step in nanotoxicological studies
13:10 14:00 Lunch
14:05 14:20 O1.11 S- Bagherifam
Univ. Oslo pH Responsive Nanoparticles for Intracellular Release of Doxorubicin
Chair: V. Mosquera
14:20 14:35 O1.12 R. F. P. Pereira
Univ. Coimbra Solid trivalent metal dodecyl sulfates: from aqueous solution to lamellar
14:35 14:50 O1.13 S. Barbosa
Univ. Santiago Compostela Protein-nanoparticle bionconjugates: Enhanced protein stability and inhibition of fibrillogenesis
14:50 15:05 O1.14 M. Coronado-Puchau
CICbiomaGUNE Enzymatic Modulation in the Growth of Gold Nanorods: Ultrasensitive detection of acetylcholinesterase inhibitors
15:05 15:20 O1.15 R. Muñoz-Espí
Max Planck Institute Nanoparticles and nanodroplets as templates for inorganic synthesis: Crystallization at surfaces and interfaces
15:20 16:25
POSTERS SPECIAL SESSION 2 Chair: R.G. Rubio
PSS12 J. C. Mejuto Univ. Vigo PSS13 L. Pérez
IQAC-CSIC PSS14 G. Prieto Univ. Santiago Compostela
PSS15 I. S. Oliveira Univ. Porto PSS16 D. Noguera-Marín
Univ. Granada PSS17 S. M. Novikov CICbiomaGUNE
PSS18 M. Pujol Univ. Barcelona PSS19 J. Juárez
Univ. Sonora PSS20 J. A. Ruiz-López Univ. Granada
PSS21 A. L. Barrán-Berdón Complutese Univ. Madrid PSS22 J. M. Peula-García
Univ. Málaga PSS23 O. Gonçalves Univ. Minho
PSS24 I. Miraballes-Martínez Univ. de la República
16:30 17:00 Coffee Break + POSTERS SESSION 5
17:00 17:20 I10 Romain Quindant
ICFO-ICREA Towards an integrated plasmonic platform for early cancer detection
Chair: L.M. Liz-Marzán
Session CLOSING TALKS
17:20 17:35 CT1 A. Elaissari
Univ. Lyon Synthesis of Nano-coral like colloidal particles via water-in-oil miniemulsion
17:35 17:50 CT2 M. Grzelczak
CICbiomaGUNE Hydrophobic Interactions Modulate Self-assembly of Gold Nanoparticles
17:50 18:05 CT3 J. J. Cerdà
IFISC-CSIC-UIB Phase diagram of Magnetic filaments in bulk and near surfaces
18:05 18:20 CT4 I. Pagonabarraga
Univ. Barcelona Wetting-induced fluid entrainment and drop emission for driven fluid filaments
18:20 18:35 CT5 T. Hellweg
Univ. Bielefeld Non-NIPAM based microgels: Tuning the volume phase transition by copolymerisation and by particle architecture
18:35 18:50 CT6 A. Guerrero-Martínez
Complutense Univ. Madrid Plasmonic Nanoparticles based on Colloid Chemistry
18:50 19:05 CT7 B. Escribano
BCAM A chemical garden model for the formation mechanism of brinicles
19:05 19:15 CLOSING CEREMONY
20:00 CONFERENCE DINNER
CONTENTS
CONTENTS 17
PLENARY LECTURES PL1 LIQUID CRYSTALLINE SUPERATOMS
T. López-León, C. Blanc, M. Nobili, A. Fernandez-Nieves 41
PL2 MOLECULAR ENGINEERING OF INORGANIC AND HYBRID NANOSTRUCTURED MATERIALS C. Sanchez
42
PL3 INORGANIC NANOCRYSTALS AS FUNCTIONAL BUILDING UNITS FOR COMPOSITES T. Trindade
43
CONTENTS 18
INVITED LECTURES I1 BIOMOLECULAR HYDROGELS – NATURE’S PLAYGROUND FOR
SUPRAMOLECULAR CHEMISTRY AND PHYSICS R. P. Richter
47
I2 BIOSURFACTANTS: POWERFUL TOOLS IN MICROBIAL ENHANCED OIL RECOVERY L. R. Rodrigues, E. J. Gudiña, J. A. Teixeira
48
I3 EFFECT OF CHARGE MOBILITY AND CHAIN LENGTH ON THE ADSORTION OF POLY-ACIDS ON OPPOSITELY CHARGED NANOPARTICLES: A MONTE CARLO SIMULATION R. S. Dias
49
I4 THE FLUCTUATION THEOREM IN DENSE COLLOIDS: A SIMULATION STUDY A. M. Puertas
50
I5 THE ION SPECIFICITY ON COLLOIDAL SYSTEMS D. Bastos-González, L. Pérez-Fuentes, C. Drummond, J. Faraudo
51
I6 ELECTRON DYNAMICS IN NANOSTRUCTURED METAL-OXIDE FILMS: NOVEL ROUTES TOWARDS CLEAN ENERGY TECHNOLOGIES J. A. Anta
52
I7 NANOSTRUCTURED SURFACES OF CONDUCTING POLYMERS AND APPLICATIONS IN ORGANIC PHOTOVOLTAIC CELLS A. Charas
53
I8 FUNCTIONAL HAIRY PARTICLES AND FILMS VIA BLOCK COPOLYMER-STABILIZED EMULSION POLYMERIZATION H. Heuts, M. Fijten, A. Muñoz-Bonilla, A. van Herk
54
I9 NANOSIZED PARTICLES: BEYOND A SIMPLE TOOL TO FIGHT AGAINST DISEASE P. Taboada
55
I10 TOWARDS AN INTEGRATED PLASMONIC PLATFORM FOR EARLY CANCER DETECTION R. Quidant
56
CONTENTS 19
CLOSING TALKS CT1 SYNTHESIS OF NANO-CORAL LIKE COLLOIDAL PARTICLES VIA
WATER-IN-OIL MINIEMULSION R. Ladj, Y. Mounier, R. Le-Dantec, H. Fessi, A. Elaissari
59
CT2 HYDROPHOBIC INTERACTIONS MODULATE SELF-ASSEMBLY OF GOLD NANOPARTICLES M. Grzelczak, A. Sánchez-Iglesias, T. Altantzi, B. Goris, J. Perez-Juste, S. Bals, G. Van Tendeloo, S. H. Donaldson Jr., B. F. Chmelka, J. N. Israelachvili, L. M. Liz-Marzán
60
CT3 PHASE DIAGRAM OF MAGNETIC FILAMENTS IN BULK AND NEAR SURFACES J. J. Cerdà, P. A. Sánchez, C. Holm, T. Sintes
61
CT4 WETTING-INDUCED FLUID ENTRAINMENT AND DROP EMISSION FOR DRIVEN FLUID FILAMENTS I. Pagonabarraga
62
CT5 NON-NIPAM BASED MICROGELS: TUNING THE VOLUME PHASE TRANSITION BY COPOLYMERISATION AND BY PARTICLE ARCHITECTURE T. Hellweg, M. Zeiser, B. Wedel
63
CT6 PLASMONIC NANOPARTICLES BASED ON COLLOID CHEMISTRY A. Guerrero-Martínez, L. M. Liz-Marzán
64
CT7 A CHEMICAL GARDEN MODEL FOR THE FORMATION MECHANISM OF BRINICLES B. Escribano
65
CONTENTS 20
ORAL COMMUNICATIONS 1. Nanoparticles: Organic, Inorganic and Hybrids
O1.1 LIGHT-ADDRESSABLE AND DEGRADABLE SILICA CAPSULES FOR CYTOSOLIC RELEASE S. Carregal-Romero, A. Ott, W. J. Parak
69
O1.2 SILICON COLLOIDS WITH A STRONG MAGNETIC RESPONSE BELOW 1.5 MICROMETERS REGION L. Shi, R. Fenollosa, F. Meseguer
70
O1.3 RESIZING OF COLLOIDAL GOLD NANORODS USING AQUEOUS K2S2O8 AND MORPHOLOGICAL PROBING BY SERS S. Fateixa, T. Trindade
71
O1.4 ORGANIZED PLASMONIC CLUSTERS WITH HIGH COORDINATION NUMBER AND EXTRAORDINARY SERS ENHANCEMENT N. Pazos-Perez, C. S. Wagner, L. M. Liz- Marzan, F. J. Garcia de Abajo, A. Wittemann, R. Alvarez-Puebla, A. Fey
72
O1.5 EFFICIENT ECO-FRIENDLY DYE NANO-ADSORBENTS BASED ON BIOPOLYMER SURFACE FUNCTIONALIZED MAGNETIC NANOPARTICLES A. L. Daniel-da-Silva, A. M. Salgueiro, B. Creaney, T. Trindade
73
O1.6 MICROFLUIDIC SELF-ASSEMBLY OF POLYMERIC NANOPARTICLES IN AQUEOUS SOLUTIONS AND CONTROLLED DRUG DELIVERY E. Dashtimoghadam, H. Mirzadeh, F. A. Taromi, B. Nyström
74
O1.7 NEW APPLICATIONS MODIFYING COLLOIDAL PARTICLES WITH ION-SPECIFIC LIGANDS D. Jimenez de Aberasturi, D. Hühn, R. Pinedo, I. Ruiz de Larramendi, T. Rojo, J. M. Montenegro-Martos, S. Carregal-Romero, W. J. Parak
75
O1.8 OPTIMIZED SYNTHESIS OF GOLD NANORODS L. Scarabelli, M. Grzeclzak, L. M. Liz-Marzán
76
O1.9 SHEARING AS A DRIVEN FORCE TO DIRECT THE ASSEMBLY OF NANOCOMPOSITES FILMS B. Martín-García, M. M. Velázquez
77
O1.10 DISSOLUTION OF ZNO NANOPARTICLES IN AQUEOUS MEDIA: A FIRST ESSENTIAL STEP IN NANOTOXICOLOGICAL STUDIES C. Rey-Castro, C. David, S. Cruz-González, J. Salvador, F. Mas, J. Puy, J. Galceran
78
CONTENTS 21
O1.11 pH RESPONSIVE NANOPARTICLES FOR INTRACELLULAR RELEASE OF DOXORUBICIN S. Bagherifam, V. Hasirci, B. Nyström, G. W. Griffiths, G. M. Mælandsmo, N. Hasirci
79
O1.12 SOLID TRIVALENT METAL DODECYL SULFATES: FROM AQUEOUS SOLUTION TO LAMELLAR SUPERSTRUCTURES R. F. P. Pereira, A. J. M. Valente, R. A. E. Castro, H. D. Burrows, V. de Zea Bermudez
80
O1.13 PROTEIN-NANOPARTICLE BIONCONJUGATES: ENHANCED PROTEIN STABILITY AND INHIBITION OF FIBRILLOGENESIS S. Goy, A. Topete, A. Cambón, E. Villar-Alvarez, N. González, M. Alatorre-Meda, E. Casals, V. F. Puntes, S. Barbosa, P. Taboada, V. Mosquera
81
O1.14 ENZYMATIC MODULATION IN THE GROWTH OF GOLD NANORODS: ULTRASENSITIVE DETECTION OF ACETYLCHOLINESTERASE INHIBITORS M. Coronado-Puchau, L. Saa, M. Grzelczak, V. Pavlov, L. M. Liz-Marzán
82
O1.15 NANOPARTICLES AND NANODROPLETS AS TEMPLATES FOR INORGANIC SYNTHESIS: CRYSTALLIZATION AT SURFACES AND INTERFACES R. Muñoz-Espí, V. Fischer, H. S. Varol, K. Landfester
83
CONTENTS 22
ORAL COMMUNICATIONS 2. Polymers, Polyelectrolytes, Surfactants and Gels
O2.1 NON-EQUILIBRIUM KINETICS IN BLOCK COPOLYMER
MICELLES OBSERVED BY MILLISECOND TIME-RESOLVED SAXS AND SANS. R. Lund
84
O2.2 A UNIQUE COLLOIDAL “CRYSTAL-GEL” STRUCTURE OBSERVED IN MICROGRAVITY CONDITIONS. J. Sabín, A. E. Bailey, G. Espinosa, B. J. Frisken
85
O2.3 pH-RESPONSE AND CROSSLINKING TIME EFFECT ON CHITOSAN NANOFILMS J. Miras, C. Liu, E. Blomberg, E. Thormann, E. Tyrode, S. Vílchez, J. Esquena, K. Persson, P. Claesson
86
O2.4 MOLECULAR DYNAMIC SIMULATIONS OF CONJUGATED POLYELECTROLYTES WITH SURFACTANTS IN SOLVENT ENVIRONMENTS B. Stewart, J. Pragana, S. M. Fonseca, T. Costa, A. T. Marques, U. Scherf, H. D. Burrows
87
O2.5 NANOSTRUCTURE OF CATIONIC SURFACTANT-DNA COMPLEXES A. Mezei, R. Pons, M. C. Morán
88
O2.6 MICELLAR SHAPE TRANSITION IN AN IMIDAZOLIUM BASED-SURFACTANT. P. Rodríguez-Dafonte, M. Figueira-González, V. Francisco, L. García-Río, E. F. Marques, M. Parajó
89
O2.7 BINDING OF CATIONIC SINGLE-CHAIN/DIMERIC SURFACTANTS TO BOVINE SERUM ALBUMIN. INFLUENCE OF THE NUMBER OF HYDROPHOBIC CHAINS AND THE PRESENCE OF AROMATIC RINGS ON PROTEIN-SURFACTANT INTERACTIONS M. L. Moyá, V. I. Martín, A. Maestre, A. Rodríguez
90
CONTENTS 23
ORAL COMMUNICATIONS 3. Soft Colloids. Soft Nanotechnology. Bioinspired Systems
O3.1 MONOOLEIN-BASED LIPOSOMES FOR SIRNA DELIVERY
A. C. N. Oliveira, T. Martens, K. Raemdonck, A. C. Gomes, K. Braeckmans, M. E. C. D. R. Oliveira
91
O3.2 THE COOPERATIVE INTERACTION BETWEEN HYDROPHOBICALLY MODIFIED INULIN AND DDAB J. Morros, M. R. Infante, M. G. Miguel, B. Lindman, R. Pons
92
O3.3 POLYMERIC NANO-EMULSIONS OBTAINED BY LOW-ENERGY METHODS AND THEIR USE FOR NANOPARTICLE TEMPLATING. M. Homs, G. Calderó, C. Solans
93
O3.4 STABLE CAPSULES FORMED BY LIPOSOMES COATED BY THE LAYER-BY-LAYER METHOD. R. G. Rubio, M. Ruano, F. Ortega
94
O3.5 SERINE-BASED CATANIONIC LIPOSOMES AS POTENTIAL NANOCARRIERS FOR MOLECULAR DELIVERY S. G. Silva, D. Félix, M. L. C. do Vale, E. F. Marques
95
O3.6 SOFT PARTICLES FOR TUNABLE NANOPHOTONICS A. Maldonado-Valdivia, B. Sierra-Martín, A. Fernández-Barbero
96
CONTENTS 24
ORAL COMMUNICATIONS 4. Colloids and Energy
O4.1 A RHEOLOGICAL STUDY OF MAGNETIC FLUIDS BASED ON
HIGHLY VISCOELASTIC SOLVENTS J. P. Segovia-Gutiérrez, R. Hidalgo-Álvarez, J. de Vicente
97
O4.2 BAND GAP ENGINEERING WITH SUBNANOMETRIC METAL (0) CLUSTERS: CATALYTIC, ELECTROCATALYTIC & PHOTOCATALYTIC APPLICATIONS M. A. López-Quintela, N. Vilar-Vidal, D. Buceta, M. C. Blanco, J. Rivas
98
CONTENTS 25
ORAL COMMUNICATIONS 5. Surfaces and Interfaces
O5.1 NMR SELF-DIFFUSION STUDIES ON THE BINDING AND
EXCHANGE DYNAMICS BETWEEN BLOCK COPOLYMERS AND CARBON NANOTUBES R. Fernandes, M. Shtein, I. P. Bar, O. Regev, I. Furó, E. F. Marques
99
O5.2 PROBING IN-VITRO DIGESTION OF INTERFACIAL PROTEIN STRUCTURES IN A SINGLE DROPLET J. Maldonado-Valderrama, J. A. Holgado-Terriza, A. Torcello-Gómez, M. A. Cabrerizo-Vílchez
100
O5.3 EFFECT OF POROSITY AND SURFACE MATERIAL IN THE TRANSPORT OF IONS ACROSS NANOPOROUS ALUMINA MEMBRANES V. Romero, V. Vega, J. García, R. Zierold, K. Nielsch, V. M. Prida, B. Hernando, J. Benavente
101
O5.4 BULK AND INTERFACIAL MICRORHEOLOGY F. Ortega, L. J. Bonales, A. Maestro, N. Mancebo, F. Martínez-Pedrero, J. E. Fernandez-Rubio, R. Chuliá, A. J. Mendoza, R. G. Rubio
102
O5.5 SEGREGATION OF SILICA PARTICLES WITH DIFFERENT SIZE USING DRIVEN RECEDING CONTACT LINES C. L. Moraila-Martínez, M. A.Cabrerizo-Vílchez, M. A. Rodríguez-Valverde
103
O5.6 IONS-INDUCED NANOSTRUCTURATION OF HYDROPHOBIC POLYMER SURFACES C. Drummond, I. Siretanu, D. Bastos, J.-P. Chapel
104
O5.7 QUANTUM DOTS ONTO POLYMER AND SURFACTANT SELF-ASSEMBLED FILMS: A QUARTZ CRYSTAL MICROBALANCE STUDY T. Alejo, M. D. Merchán, M. M. Velázquez
105
O5.8 SUDDEN FIELD INDUCED SUBLIMATION IN 2D COLLOIDAL CRYSTALLITES F. Martínez-Pedrero, J. E. Fernandez-Rubio, R. G. Rubio, F. Ortega
106
CONTENTS 26
ORAL COMMUNICATIONS 6. Modeling and Simulations
O6.1 STOCHASTIC DIFFUSION OF ISOTROPIC AND LIQUID CRYSTAL
PHASES OF RODLIKE COLLOIDAL PARTICLES: MONTE CARLO AND BROWNIAN DYNAMICS MEET A. Patti, A. Cuetos
107
O6.2 COARSE-GRAINED MONTE CARLO SIMULATIONS OF THERMO-RESPONSIVE POLYELECTROLYTE NANOGELS M. Quesada-Pérez, J. A. Maroto-Centeno, A. Martín-Molina
108
O6.3 EFFECTIVE ELECTROSTATIC INTERACTIONS ARISING IN CORE-SHELL CHARGED MICROGEL SUSPENSIONS WITH ADDED SALT A. Moncho-Jordá, J. A. Anta, J. Callejas-Fernández
109
O6.4 NON-RANDOM ADSORPTION OF POLYELECTROLYTES IN REGULARLY CHARGED SURFACES. FROM SINGLE CHAIN TO MULTICHAIN DEPOSITION S. C. C. Nunes, T. Firmino, A. A. C. C. Pais
110
O6.5 A MOLECULAR INSIGHT ON NEW VESICULAR SYSTEMS FORMED BY SELF-ASSEMBLY OF STEROLS AND QUATERNARY AMMONIUM SURFACTANTS J. Faraudo, L. Ferrer-Tasies, E. Moreno-Calvo, M. Cano-Sarabia, M. Aguilella-Arzo, A. Angelova, S. Lesieur, S. Ricart, N. Ventosa, J. Veciana
111
O6.6 INTERNAL AND FREE ENERGY IN A PAIR OF LIKE-CHARGED COLLOIDS. CONFINED AND BULK FLUIDS. A. Cuetos, J. A. Anta, A. Puertas
112
CONTENTS 27
ORAL COMMUNICATIONS 7. Biotechnological Applications
O7.1 MULTIPLEXED PLASMON SENSOR FOR RAPID LABEL-FREE
ANALYTE DETECTION R. Ahijado-Guzmán, C. Rosman, J. Prasad, A. Neiser, A. Henkel, J. Edgar, C. Sönnichsen
113
O7.2 DEVELOPMENT OF DODAB:MO LIPOSOMES FOR GENE DELIVERY J. P. N. Silva, A. C. N. Oliveira, A. F. C. Gomes, M. E. C. D. R. Oliveira
114
O7.3 USING AFM TO STUDY THE COMPLEXATION OF DNA AND ANIONIC LIPID MEDIATED BY Ca2+ AT THE AIR-WATER INTERFACE G. Luque-Caballero, A. Martín-Molina, J. Maldonado-Valderrama
115
O7.4 GENE TRANSFER MEDIATED BY BIS-QUATERNARY GEMINI SURFACTANTS DEPENDS ON COMPLEX ARCHITECTURE A. M. Cardoso, C. M. Morais , S. G. Silva , M. L. do Vale, E. F. Marques, M. C. P. de Lima, A. S. Jurado
116
CONTENTS 28
POSTERS SPECIAL SESSIONS PSS01 LUMINISCENT/MAGNETIC LIPOSOMES WITH RGD-CONJUGATE
PEPTIDE FOR THERANOSTIC APPLICATIONS M. A. Busquets, E. Escribano, J. Queralt, M. Sangrà, M. Gallardo, J. Estelrich
119
PSS02 INTERFACIAL ACTIVITY COMPARISON BETWEEN BARE, HOMOGENEOUS AND JANUS GOLD NANOPARTICLES M. A. Fernandez-Rodriguez, M. A. Rodriguez-Valverde, M. A. Cabrerizo-Vilchez,Y. Song, S. Chen, A. Sánchez-Iglesias, L. M. Liz-Marzán, R. Hidalgo-Alvarez
120
PSS03 GROWTH OF METAL SULFIDES ON POLYMER BEADS: A STARTING POINT FOR NANOCAPSULES M. C. Neves, M. M. Silva, D. Lopes, T. Trindade
121
PSS04 SYNTHESIS AND MODIFICATION OF METAL NANOPARTICLES IN ORGANIC MEDIUM FOR PLASMONIC APPLICATIONS L. Polavarapu, L. M. Liz-Marzán
122
PSS05 METALLIC JANUS PARTICLES D. Rodríguez-Fernández, J. Pérez-Juste, I. Pastoriza-Santos, L. M. Liz-Marzán
123
PSS06 OIL-IN-WATER MICROEMULSIONS FOR THE SYNTHESIS OF CeO2, CuO, AND CuO/CeO2 NANOPARTICLES AND THEIR USE AS PHOTOCATALYSTS M. Sánchez-Domínguez, A. V. Vela-Gonzalez, K. Pemartin, C. Solans, S. A. Pérez-García, C. C. Leyva-Porras, I. Juárez-Ramírez
124
PSS07 PREPARATION OF ORGANIC SOLVENT RESISTANT NANOCARRIERS FROM O/W NANO-EMULSIONS AS TEMPLATES S. Vílchez-Maldonado, R. Molina, J. Esquena, G. Calderó
125
PSS08 INTERACTION BETWEEN A ZWITTERIONIC THIOPHENE BASED CONJUGATED POLYELECTROLYTE AND SURFACTANTS IN AQUEOUS SOLUTION T. Costa, D. de Azevedo, M. Knaapila, A. Valente, M. Kraft, U. Scherf, H. D. Burrows
126
PSS09 IONIZATION BY pH AND ANIONIC SURFACTANT BINDING GIVES THE SAME THICKENING EFFECTS OF CROSSLINKED POLYACRYLIC ACID DERIVATIVES C. M. G. Duarte, L. Alves, F. E. Antunes, B. Lindman, B. Klotz, A. Böttcher, H.-M. Haake
127
PSS10 THE INFLUENCE OF THE COMBINATION OF Fe(III) IONS WITH BPEI AND LPEI IN DNA CONDENSATION: PHYSICO-CHEMICAL CHARACTERIZATION AND IN VITRO CYTOTOXICITY TESTING A. F. Jorge, M. C Morán, M. P. Vinardell, R. S. Dias, A. A. C. C. Pais
128
CONTENTS 29
PSS11 CHARACTERIZATION OF WATER/SODIUM DODECYL SULPHATE/PROPANOL/ALLYLBENZENE MICELLAR SYSTEMS M. Fanun
129
PSS12 INFLUENCE OF HUMIC ACIDS AS COLLOIDAL SYSTEMS ON THE STABILITY OF XENOBIOTICS J. C. Mejuto, J. Morales, O. Moldes, J. A. Manso
130
PSS13 DRUG DELIVERY SYSTEMS BASED ON DIACYL ARGININE SURFACTANTS: PREPARATION, CHARACTERIZATION AND EVALUATION OF THEIR BIOLOGICAL ACTIVITY L. Pérez, L. Tavano, M. R. Infante, A. Pinazo, M. A. Manresa, M. P. Vinardell, M. Mitjans
131
PSS14 STUDY OF THE STABILITY OF POLYETHYLENIMINE-DECORATED LIPOSOMES G. Prieto, J. Sabín, C. Vázquez-Vázquez, F. Bordi, F. Sarmiento
132
PSS15 NOVEL SERINE-BASED GEMINI SURFACTANTS FOR GENE DELIVERY: PHYSICOCHEMICAL AND COMPACTION STUDIES S. G. Silva, I. S. Oliveira, M. L. C. do Vale, E. F. Marques
133
PSS16 EFFECT OF THE ELECTROSTATIC INTERACTIONS IN THE NANOPARTICLE PATTERNING USING DRIVEN EVAPORATING MENISCI D. Noguera-Marín, C. L. Moraila-Martinez, M. Cabrerizo-Vilchez, M. A. Rodriguez-Valverde
134
PSS17 SURFACE ENHANCED RAMAN SCATTERING MICROSCOPY WITH SUBSTRATES FABRICATED BY AU &AG “NANO-INKS” S. M. Novikov, l. Polavarapu, L. M. Liz-Marzán
135
PSS18 SURFACE BEHAVIOR OF BINARY SYSTEMS CONSISTING OF E1(70-87) PEPTIDE FROM HGV-C VIRUS AND VARIOUS PHOSPHOLIPIDS M. Pujol, A. Ortiz, M. Muñoz-Juncosa, J. Prat, V. Girona, M. A. Alsina
136
PSS19 OLIGOMER, PROTOFIBRILLAR AND FIBRILLAR AGGREGATES FROM RECOMBINANT HUMAN LYSOZYME: SURFACE PROPERTIES AND CYTOTOXIC EFFECT E. D. Ruiz, G. Burboa, J. Juárez, P. Taboada, V. Mosquera, M. A. Valdes
137
PSS20 ON THE INITIAL-GAP DEPENDENCE OF MAGNETORHEOLOGICAL PERFORMANCE UNDER SQUEEZING FLOW J. A. Ruiz-López, R. Hidalgo-Álvarez, J. de Vicente
138
CONTENTS 30
PSS21 HOW CHIRALITY MAY AFFECT TO THE SELF-AGGREGATION PATTERN OF LYSINE-BASED CATIONIC GEMINI LIPIDS AND THEIR INTERACTION WITH PLASMID DNA? RIBBON-TYPE AND CLUSTER-TYPE LIPOPLEXES A. L. Barrán-Berdón, M. Muñoz-Úbeda, C. Aicart-Ramos, L. Pérez, A. Martín-Molina, P. Castro-Hartmann, E. Aicart, E. Junquera
139
PSS22 LIPID-POLOXAMER NANOEMULSIONS AS POTENTIAL BIOLOGICAL CARRIERS L. García-Jara, A. Martín-Rodríguez, J. A. Marchal-Corrales, Gema Jimenez, J. M. Peula-García
140
PSS23 DODAC:MO:DC-CHOL/CHEMS LIPOPLEXES FOR GENE DELIVERY O. Gonçalves, H. Carvalho, J. P. N. Silva, A. C. Gomes, M. E. C. D. R. Oliveira
141
PSS24 DEVELOPMENT AND CHARACTERIZATION OF FLUORESCENT MICROSPHERES AS A PROBE FOR PARTICLE UPTAKE ASSAYS BY FLOW CITOMETRY C. Sóñora, A. Hernández, I. Miraballes- Martínez
142
CONTENTS 31
POSTERS P01 HYBRID CORROLE-GOLD NANOPARTICLES
J. F. B. Barata, A. L. Daniel-da-Silva, M. Graça, P. M. S. Neves, J. A. S. Cavaleiro, T. Trindade
145
P02 OPTIMIZATION OF A NANOSTRUCTURED LIPID CARRIERS FORMULATION FOR PORPHYRIN DELIVERY BASED ON FACTORIAL DESIGN L. Damas, C. Vitorino, J. J. Sousa, M. Piñeiro, A. A. C. C. Pais
146
P03 CHITOSAN OR ALGINATE-COATED IRON OXIDE NANOPARTICLES: A COMPARATIVE STUDY J. Estelrich, J. Castelló, M. A. Gallardo, M. A. Busquets
147
P04 BROADBAND DIELECTRIC SPECTROSCOPY TO STUDY COLLOIDAL MATERIALS E. Galera-Cortés, J. D. Solier, J. Estelrich, R. Hidalgo-Álvarez
148
P05 CLEANING OF DRIED STARCH IN STAINLESS STEEL WITH SURFACTANT SOLUTIONS CONTAINING MICRO- AND NANOPARTICLES E. Jurado, J. M. Vicaria, O. Herrera-Márquez, A. Plaza
149
P06 HYBRID MAGNETIC POLYMERIC NANOPARTICLES PREPARED VIA MINIEMULSION POLYMERIZATION C. Kaewsaneha, P. Tangboriboonrat, D. Polpanich, A. Elaissari
150
P07 SERS PERFORMANCE OF GOLD NANOSTARS J. Langer, A. Shiohara, A. Sánchez-Iglesias, L. M. Liz-Marzán
151
P08 PS-PAA-CAPPED GOLD NANOSTARS AS SERS SUBSTRATE FOR THE DETECTION OF HYDROPHOBIC MOLECULES A. La Porta, A. Sánchez-Iglesias, M. Grzelczak, L. M. Liz-Marzán
152
P09 COMB-LIKE ACRYLIC-BASED POLYMER LATEXES CONTAINING NANO-SIZED CRYSTALLISABLE DOMAINS E. Mehravar, J. R. Leiza, J. M. Asua
153
P10 SYNTHESIS AND PHOTOCATALYTIC PROPERTIES OF TITANATES NANOTUBES SENSITIZED BY CRYSTALLINE Ag2S NANOPARTICLES M. C. Neves, A. J. Silvestre, M. R. Nunes, O. C. Monteiro
154
P11 HIGHLY ORGANIZED PLASMONIC NANOPARTICLES: UNIFORM PLASMONIC STRUCTURES AS SERS PLATFORMS N. Pazos-Perez, M. Tebbe, R. Alvarez-Puebla, A. Fey
155
P12 FERROMAGNETIC ANISOTROPIC NANOSTRUCTURES FOR AQUEOUS METAL IONS UPTAKE P. C. Pinheiro, D. S. Tavares, A. L. Daniel-da-Silva, C. B. Lopes, E. Pereira, J. P. Araújo, C. T. Sousa, T. Trindade
156
CONTENTS 32
P13 PAMAM DENDRIMERS EXERTED OXIDATIVE DAMAGE AND STRUCTURAL ALTERATIONS IN GREEN ALGAE AND CYANOBACTERIA I. Rodea-Palomares, S. Gonzalo, F. Leganés, E. García-Calvo, F. Fernández-Piñas, R. Rosal
157
P14 STERIC HINDRANCE INDUCES CROSS-LIKE SELF-ASSEMBLY OF GOLD NANODUMBBELLS A. Sánchez-Iglesias, M. Grzelczak, H. H. Mezerji, S. Bals, J. Pérez-Juste, L. M. Liz-Marzán
158
P15 NOBLE METAL NANOPARTICLES COATED WITH MESOPOROUS MATERIALS M. N. Sanz-Ortiz, L. M. Liz-Marzán
159
P16 FORMATION OF PLASMONIC HETEROSTRUCTURES VIA COVALENT BOND CHEMISTRY A. B. Serrano-Montes, M. Grzelczak, L. M. Liz-Marzán
160
P17 VARIOUS STRATEGIES OF GOLD NANOSTAR SYNTHESIS FOR SERS APPLICATIONS A. Shiohara, L. M. Liz-Marzán
161
P18 A SIMPLE METHOD TO PREPARE SORBENTS BASED ON MAGNETITE COATED WITH SILICEOUS HYBRID SHELLS FOR THE REMOVAL OF NON-ESSENTIAL METAL IONS FROM WATERS D. S. Tavares, A. L. Daniel-da-Silva, C. B. Lopes, N. J. O. Silva, V. S. Amaral, J. Rocha, E. Pereira, T. Trindade
162
P19 ANISOTROPIC GOLD/PLGA NANOHYBRIDS FOR CANCER THERAPY AND IMAGING A. Topete, A. Cambón, E. Vilar, M. Alatorre-Meda, S. Barbosa, S. Carregal-Romero, W. Parak, P. Taboada, V. Mosquera
163
P20 THERMAL EFFECTS IN LOADED LIPID NANOPARTICLES DISPERSION AND HYBRID MEMBRANES (POSTER, NANOPARTICLES: ORGANIC, INORGANIC AND HYBRIDS) M. I. Vazquez, J. Hierrezuelo, J. M. López-Romero, J. Benavente
164
P21 CONTROL OF THE AGGREGATION OF PRIMARY NANOCRYSTALS DURING PARTICLE GROWTH: FROM SMOOTH TO ROUGH MAGNETITE PARTICLES F. Vereda, M. P. Morales, B. Rodríguez-González, J. de Vicente, R. Hidalgo-Álvarez
165
P22 SYNTHESIS OF ZnO/Ag HYBRID NANOMATERIALS AND STUDY OF THEIR ELECTRICAL PROPERTIES (POSTER, TOPIC: NANOPARTICLES: ORGANIC, INORGANIC AND HYBRIDS) G. Vidal-Lopez, K. Pemartin, C. Solans, A. Morales-Sanchez, M. Sanchez-Dominguez
166
CONTENTS 33
P23 DESIGN OF A DUAL NANOSTRUCTURED LIPID CARRIERS FORMULATION BASED ON PHYSICOCHEMICAL, RHEOLOGICAL AND MECHANICAL PROPERTIES C. Vitorino, L. Alves, F. E. Antunes, J. J. Sousa, A. A. C. C. Pais
167
P24 THERMODYNAMIC STUDY OF THE INTERACTION BETWEEN 5,10,15,20-TETRAKIS-(N-METHYL-4-PYRIDYL)PORPHYRIN TETRAIODINE AND SODIUM DODECYL SULFATE: A CONDUCTOMETRIC STUDY C. M. R. Almeida, R. F. P. Pereira, B. F. O. Nascimento, M. Pineiro, A. J. M. Valente
168
P25 RHEOLOGICAL STUDIES OF UNMODIFIED CELLULOSE SOLUTIONS BASED ON NEW PROMISING ALKALI SOLVENT SYSTEMS L. Alves, C. Costa, F. Antunes, B. Medronho, B. Lindman
169
P26 NANOSTRUCTURING CONJUGATED POLYELECTROLYTES IN TETRAETHYLENE GLYCOL MONODODECYL ETHER/WATER LIQUID CRYSTALS H. D. Burrows, M. Knaapila, S. M. Fonseca, B. Stewart, M. Torkkeli, J. Perlich, S. Pradhan, U. Scherf
170
P27 A NOVEL APPROACH TO THE DEVELOPMENT OF UNMODIFIED CELLULOSE SOLVENTS C. Costa, L. Alves, F. Antunes, B. Medronho, M. G. Miguel, B. Lindman
171
P28 WATER-BORNE PRESSURE SENSITIVE ADHESIVES BASED ON RENEWABLE PROTIC IONIC LIQUIDS A. M. Fernandes, M. Moreno, A. Adboudzadeh, R. Gracia, M. J. Barandiaran, D. Mecerreyes
172
P29 BIOMIMETIC TRIBLOCK COPOLYMER MEMBRANES: FROM AQUEOUS SOLUTIONS TO SOLID SUPPORTS A. González-Pérez, V. Castelletto, I. Hamley, A. Topete, E. Villar-Alvarez, N. González, A. Cambón, S. Barbosa, P. Taboada, V. Mosquera
173
P30 SPECTROSCOPIC STUDY OF THE INTERACTION OF HECAMEG WITH BOVINE SERUM ALBUMIN AND ITS EFFECT ON THE PROTEIN CONFORMATION J. M. Hierrezuelo, B. Nieto-Ortega, C. Carnero-Ruiz
174
P31 NOVEL STRUCTURAL CHANGES DURING TEMPERATURE-INDUCED SELF-ASSEMBLING AND GELATION IN AQUEOUS SOLUTIONS OF THE COPOLYMER PLGA1170-PEGN-PLGA1170 N. Khorshid, K. Knudsen, S. A. Sande, B. Nyström
175
P32 SYNTHESIS AND MINERALIZATION OF A POLYMERIC NETWORK USING THE REACTION DIFFUSION METHOD E. Lopez-Cabarcos, Y. Ramadan, J. Rubio-Retama
176
CONTENTS 34
P33 ADSORPTION OF POLYELECTROLYTE-SURFACTANT MIXTURES OF COSMETIC INTEREST S. Llamas, R. G. Rubio, F. Ortega, N. Baghdadli, G. Luengo, C. Cazeneuve
177
P34 MOLECULAR DYNAMICS SIMULATIONS OF SURFACTANT MICELLES V. I. Martín, L. J. Álvarez, M. L. Moyá
178
P35 SYNTHESIS AND PHYSICOCHEMICAL CHARACTERIZATION OF ALKANEDYIL-BIS(DIMETHYLDODECYLAMMONIUM) BROMIDE, 12-S-12,2BR-, SURFACTANTS WITH S=7, 9 ,11 IN AQUEOUS MEDIUM V. I. Martín, A. Rodríguez, A. Maestre, M. L. Moyá
179
P36 A COMPARATIVE THERMODYNAMIC ANALYSIS OF CLOUDING PHENOMENON IN MIXTURES OF SUGAR-BASED SURFACTANTS WITH TRITON X-100 J. A. Molina-Bolívar, M. Naous, J. M. Hierrezuelo, C. Carnero-Ruiz
180
P37 MORPHOLOGICAL AND PROTEIN BINDING STUDIES IN LYSINE-BASED SELF-ASSEMBLED NANO/MICRO-TUBES I. S. Oliveira, M. J. Araújo, E. F. Marques
181
P38 SHAKE INDUCED GELATION OF PARTICLE-POLYMER DISPERSIONS R. Perea, M. M. Ramos-Tejada, P. Luckam
182
P39 PERMEABILITY-TUNABLE MICROGELS B. Sierra-Martín, A. Maldonado-Valdivia, A. Fernández-Barbero
183
P40 RATIONAL DESIGN OF CLEAVABLE CATIONIC GEMINI SURFACTANTS: EXPLORING THE MULTIFUNCTIONALITY OF SERINE AS HEADGROUP S. G. Silva, C. Alves, A. M. S. Cardoso, A. S. Jurado, M. C. P. Lima, M. L. C. do Vale, E. F. Marques
184
P41 KINETICS AND MECHANISMS OF THERMAL DEGRADATION OF WATER BORNE poly(BA/MMA)/GRAPHENE COMPOSITES D. Spasevska, A. Arzac, J. Blazevska-Gilev, R. Fajgar, R. Tomovska
185
P42 POLY(N-VINYLCAPROLACTAM) NANOGELS: A LIGHT SCATTERING STUDY J. Callejas-Fernández, J. Ramos, A. Imaz, J. Forcada, M. Quesada-Pérez, A. Moncho-Jordá
186
P43 NEW SORBENTS BASED ON SILICA-CARRAGEENAN HYBRIDS R. S. Carvalho, D. S. Tavares, A. L. Daniel-da-Silva, T. Trindade
187
P44 LYSINE BASED CATIONIC SURFACTANTS AT THE AIR-WATER INTERFACE. MIXED MONOLAYERS WITH DPPC: AN INVESTIGATION INTO THE ANTIMICROBIAL ACTIVITY A. Colomer, L. Perez, M. R. Infante, R. Pons, A. Manresa, M. J. Espuny, A. Pinazo
188
CONTENTS 35
P45 SUPRAMOLECULAR AGGREGATION IN CATIONIC/ANIONIC MIXTURES OF CALIXARENE AND SERINE-BASED SURFACTANTS C. Costa, V. Francisco, M. L. C. do Vale, L. Garcia-Rio, E. F. Marques
189
P46 THE ROLE OF THE IONIC SPECIFICITY ON THE NANOGEL AGGREGATION V. D. G. González, D. Bastos-González, J. Callejas-Fernández, M. Tirado-Miranda
190
P47 RHAMNOLIPID CHARACTERIZATION AND ITS INFLUENCE ON DPPC BILAYER ORGANIZATION E. Haba, R. Pons, L. Pérez, A. Manresa, A. Pinazo
191
P48 STRUCTURE AND PLASMON COUPLING OF 2D Au@PNIPAM MICROGEL ARRAYS WITH THERMALLY CONTROLLED INTERPARTICLE GAP A. Maldonado-Valdivia, J. Clara-Rahola, R. Contreras-Cáceres, B. Sierra-Martín, A. Fernández-Barbero
192
P49 INFLUENCE OF XENOBIOTICS ON THE STABILITY OF NATURAL MICELLAR AGGREGATES J. Morales, J. A. Manso, M. Arias-Estevez, J. C. Mejuto
193
P50 STABILITY OF CARBOFURAN IN RESTRICTED AQUEOUS MEDIA J. Morales, J. A. Manso, A. Cid, M. A. Iglesias-Otero, J. C. Mejuto
194
P51 EFFECT OF MIXED CROWDING MEDIA ON THE DIFFUSION OF ALPHA-CHYMOTRYPSIN I. Pastor, E. Vilaseca, S. Madurga, J. L. Garcés, M. Cascante, F. Mas
195
P52 STABILITY OF THE POLYMER LAYERS FORMED BY THE LAYER-BY-LAYER METHOD R. Perea, M. M. Ramos-Tejada, K. Rudzka, A. V. Delgado
196
P53 OSTWALD RIPENING INHIBITION OF CONCENTRATED LIMONENE EMULSIONS L. M. Pérez-Mosqueda, P. Ramírez, J. Muñoz
197
P54 STUDIES ON THE COLLOIDAL STABILITY OF F-DPPC AND DPPC LIPOSOMES. THE INFLUENCE OF CA2+ AND THE INTERDIGITED BILAYER ON THE AGGREGATION PROCESS G. Prieto, P. Toimil, R. Daviña, F. Sarmiento
198
P55 MICROFLUIDIC SYNTHESIS OF SILICONE CAPSULES FOR ENCAPSULATION AND RELEASE APPLICATIONS N. Vilanova, C. Rodríguez-Abreu, A. Fernández-Nieves, C. Solans
199
P56 CONTACT ANGLE HYSTERESIS OF COMMERCIALLY PURE TITANIUM SURFACES FUNCTIONALIZED WITH ORGANOPHOSPHONATES D. Blasco-Avellaneda, A. Y. Sánchez-Treviño, M. A. Rodríguez-Valverde, M. A. Cabrerizo-Vílchez
200
CONTENTS 36
P57 SELF-ASSEMBLED 2D ARRAYS OF Au NANOPARTICLES J. J. Giner-Casares, L. M. Liz-Marzán
201
P58 LIPID SPECIFICITY FOR THE INTERACTION OF A NOVEL ANTIMICROBIAL PEPTIDE SP85 WITH MODEL MEMBRANES A. Grau-Campistany, M. Pujol, F. Rabanal, Y. Cajal
202
P59 NAPHTHENIC BITUMEN-CALCITE AGGREGATE WETTABILITY AT HIGH TEMPERATURE F. Guerrero-Barba, J. E. Arellano-Varela, M. A. Cabrerizo-Vílchez, M. A. Rodríguez-Valverde
203
P60 SURFACE TENSIONS AND ACTIVITY COEFFICIENTS FOR AQUEOUS SOLUTIONS OF LAURYL ETHER ETHOXYLATES J. L. López-Cervantes, J. Gracia-Fadrique, E. Acosta, E. Calvo, A. Amigo
204
P61 MODULATION OF FILM MORPHOLOGY AT NANOSCALE BY DIPPING, LANGMUIR-BLODGETT AND LANGMUIR-SCHAEFER M. D. Merchán, T. Alejo, M. M. Velázquez
205
P62 IMPLICATION OF A PEPTIDE SEQUENCE FROM GB VIRUS C IN THE INHIBITION OF HIV FUSION PEPTIDE M. Muñoz, J. Prat, M. A. Busquets, M. Pujol, A. Ortiz, O. Domènech, M. A. Alsina, V. Girona
206
P63 STUDY OF THE BEHAVIOR OF POLY(NIPAM) MICROGELS UNDER IONIC SPECIFIC CONDITIONS: ELECTROKINETIC AND AFM MEASURES L. Pérez-Fuentes, C. Drummond, D. Bastos-González
207
P64 PROPERTIES OF CHITOSAN-INSULIN COMPLEXES OBTAINED BY AN ALKYLATION REACTION ON CHITOSAN E. Robles, J. Juárez, M. Alatorre-Meda, M. G. Burboa, P. Taboada, V. Mosquera, M. A. Valdez
208
P65 FROM 2D TO 3D AT THE AIR/WATER INTERFACE: THE SELF-AGGREGATION OF THE ACRIDINE DYE IN MIXED MONOLAYERS C. Rubia-Payá, E. Jimenez-Millán, J. J. Giner-Casares, G. Brezesinski, M. T. Martín-Romero, L. Camacho
209
P66 IN-SITU MONITORING OF BIOMIMETIC HYDROXYAPATITE GROWTH ON FUNCTIONALIZED TITANIUM SURFACES: AN AFM STUDY A. Y. Sánchez-Treviño, M. A. Fernandez-Rodríguez, M. A. Rodríguez-Valverde, M. A. Cabrerizo-Vílchez
210
P67 USING ARTIFICIAL INTELLIGENCE BASED TOOLS FOR PREDICTING THE CMC OF NON-IONIC SURFACTANTS G. Astray, O. A. Moldes, M. A. Iglesias-Otero, J. C. Mejuto
211
CONTENTS 37
P68 A NUMERICAL TOOL FOR ANALYZING EQUILIBRIUM CAPILLARY RISE D. Blasco-Avellaneda, A. Amirfazli, M. A. Rodríguez-Valverde, M. A. Cabrerizo-Vílchez
212
P69 SELF-ASSEMBLY OF A LONG-CHAIN IONIC SURFACTANT AT LOW CONCENTRATIONS: A SIMULATION STUDY J. Burgos, C. Solans, A. Patti
213
P70 BALANCE HIDROFÍLICO-LIPOFÍLICO HLBTR. ESCALA TERMODINÁMICA J. Gracia-Fadrique, J. L. López-Cervantes, F. D. Sandoval-Ibarra, A. Amigo-Pombo
214
P71 COMPUTATIONAL TOOLS FOR FORECASTING THE EFFECT OF SMALL ORGANIC MOLECULES UPON ELECTRIC PERCOLATION OF AOT-BASED MICROEMULSIONS O. A. Moldes, G. Astray, A. Cid, J. C. Mejuto
215
P72 DOES INCUBATION TIME AFFECT THE FORMATION OF THE PROTEIN CORONA? A. L. Barrán-Berdón, D. Pozzi, G. Caracciolo, A. L. Capriotti, G. Caruso, C. Cavaliere, A. Riccioli, S. Palchetti, A. Laganà
216
P73 THE EFFECT OF FLUORINATED CHOLESTEROL DERIVATIVE ON THE STABILITY AND PHYSICAL PROPERTIES OF CATIONIC DNA VECTORS A. Martín-Molina, D. Paiva, I. Cardoso, M. Quesada-Pérez, M. d. C. Pereira, S. Rocha
217
P74 BIONANOPARTICLES A. Pikabea, G. Aguirre, A. Imaz, J. Ramos, J. Forcada
218
P75 SYNTHESIS AND CHARACTERIZATION OF DEGRADABLE AND BIOCOMPATIBLE POLY( -AMINO ESTER)-DNA COMPLEXES A. Rata-Aguilar, J. L. Ortega-Vinuesa, A. B. Jódar-Reyes, A. Martín-Rodríguez, N. Segovia-Ramos, V. Ramos-Pérez, S. Borrós
219
P76 SILICON COLLOIDS BASED APPLICATIONS TO BIOSENSING AND SUN RESISTANT MATERIALS I. Rodriguez, R. Fenollosa, F. Meseguer
220
P77 SURFACE MODIFICATION OF LIPID NANOPARTICLES USING POLOXAMER 407 SURFACTANT. EFFECTS ON CELLULAR UPTAKE P. Sánchez-Moreno, J. L. Ortega-Vinuesa, J. A. Marchal-Corrales, A. Salvati, K. A. Dawson, J. M. Peula-García
221
CONTENTS 38
P78 RATIONALE DESIGN OF NANOEMULSIONS FOR THE DELIVERY OF HYDROPHOBIC BIOACTIVE COMPOUNDS: FROM SURFACTANTS AND INTERFACES TO IN VIVO RESULTS M. Wulff-Pérez, A. Martín-Rodríguez, J. de Vicente, A. Serrano, F. J. Pavón, M. J. Gálvez-Ruíz
222
PLENARY LECTURES
PLENARY LECTURES 41
PL1 Liquid crystalline superatoms
T. Lopez-Leon1,*, C. Blanc2, M. Nobili2 and A. Fernandez-Nieves3
1ESPCI-ParisTech, UMR CNRS Gulliver 7083, F-75005 Paris, France. 2Université de Montpellier II, UMR CNRS L2C 5221, F-34095 Montpellier, France. 3Georgia Institute of Technology, School of Physics, Atlanta, Georgia 30332, USA.
In many aspects, colloids behave as big atoms [1]; however, the usual absence of directionality in the interaction between colloids has limited the complexity of the structures that they can spontaneously form [2]. As a result, low-coordination structures, common in atomic and molecular systems, are rare in the colloidal domain. One way to address this is to exploit the anisotropy that spontaneously arises when a colloidal particle is coated by a nematic liquid crystal. In this spherical geometry, the orientational molecular order of the nematic liquid crystal is disrupted by the presence of singularities or topological defects, which appear symmetrically organized on the particle surface. These topological defects are not only mathematic concepts, but also high energy spots suitable for chemical attack that could be functionalized with ligands and act as attractive patches between particles [3,4]. The number and arrangement of these defects can vary, providing flexibility for tuning directional interactions. We have recently shown that these defects can be engineered to emulate the linear, trigonal and tetrahedral geometries of sp, sp2, and sp3carbon bonds [5]. These symmetries represent just a small sample of the variety of configurations that we can generate by tuning parameters such as shell geometry, temperature, or symmetry of the liquid crystal phase, which has revealed a vast playground for the formation of complex colloidal superlattices [5,6]. [1] Poon, W., Science, 2004, 304, 830-831. [2] Nelson E. C.; Braun P. V., Science, 2007, 328, 924-925. [3] DeVries, G. A.; Brunnbauer, M.; Hu, Y.; Jackson, A. M.; Long, B.; Neltner, B. T.; Uzun, O;
Wunsch, B. H.; Stellacci, F., Science, 2007, 315, 358-361 [4] Gharbi, M. A.; Se�, D.; Lopez-Leon, T.; Nobili, M.; Ravnik, M.; Žumer, S.; Blanc, C., Soft Matter,
2013, in press. [5] Lopez-Leon, T.; Koning, V.; Devaiah, K. B. S.; Vitelli, V.; Fernandez-Nieves, A. Nature Phys.,
2011, 7, 391-394. [6] Lopez-Leon, T.; Fernandez-Nieves, A.; Nobili, M.; Blanc, C. Phys. Rev. Lett., 2011, 106, 247802.
PLENARY LECTURES 42
PL2 Molecular engineering of Inorganic and Hybrid Nanostructured Materials
Clément Sanchez* Collège de France, Laboratoire de Chimie de la Matière Condensée de Paris, CNRS, Université Pierre
et Marie Curie. Collège de France, 11 Place Marcelin Berthelot, Bâtiment D. 75231, Paris, France. *[email protected]
Hybrid inorganic-organic materials can be broadly defined as synthetic materials with organic and inorganic components which are intimately mixed. They can be either homogeneous systems derived from monomers and miscible organic and inorganic components, or heterogeneous and phase-separated systems where at least one of the components’ domains has a dimension ranging from a few Å to several nanometers. Hybrid phases can also be used to nanostructure or texture new inorganic nanomaterials (porous or non porous). The mild synthetic conditions provided by the sol-gel process such as metallo-organic precursors, low processing temperatures and the versatility of the colloidal state allow for the mixing of the organic and inorganic components at the nanometer scale in virtually any ratio. These features, and the advancement of organometallic chemistry and polymer and sol-gel processing, make possible a high degree of control over both composition and structure (including nanostructure) of these materials, which present tunable structure-property relationships. This, in turn, makes it possible to tailor and fine-tune properties (mechanical, optical, electronic, thermal, chemical…) in very broad ranges, and to design specific systems for applications. Hybrid materials can be processed as gels, monoliths, thin films, fibers, particles or powders or can be intermediates to design materials having complex shapes or hierarchical structures. The seemingly unlimited variety, unique structure-property control, and the compositional and shaping flexibility give these materials a high potential in catalysis, biocatalysis, photocatalysis, etc…. This lecture will describe some recent advances on the chemistry and processing of nanostructured and hierarchically structured functional inorganic and hybrid solids. Some of their properties will be discussed.
A few recent reviews: Aerosol Route to Functional Nanostructured Inorganic and Hybrid Porous Materials. Boissiere, C.; Grosso, D.;
Chaumonnot, A.; et al., Adv. Mater., 2011, 23, 599-623 Applications of advanced hybrid organic-inorganic nanomaterials: from laboratory to market. Sanchez, C.;
Belleville, P.; Popall, M.; et al., Chem Soc. Rev., 2011, 40, 696-753 Molecular and supramolecular dynamics of hybrid organic-inorganic interfaces for the rational construction of
advanced hybrid nanomaterials. Grosso, D.; Ribot, F.; Boissiere, C.; et al., Chem. Soc. Rev., 2011, 40, 829-848 Design and properties of functional hybrid organic-inorganic membranes for fuel cells. Laberty-Robert, C.; Valle,
K.; Pereira, F.; et al. Chem. Soc. Rev., 2011, 40, 961-1005 Titanium oxo-clusters: precursors for a Lego-like construction of nanostructured hybrid materials. Rozes, L.;
Sanchez, C., Chem. Soc. Rev., 2011, 40, 1006-1030 Bio-inspired synthetic pathways and beyond: integrative chemistry. Prouzet, E.; Ravaine, S.; Sanchez, C.; et al.,
New J. Chem., 2008, 32, 1284-1299 Design, synthesis, and properties of inorganic and hybrid thin films having periodically organized nanoporosity.
Sanchez, C.; Boissiere, C.; Grosso, D.; et al., Chem. Mater., 2008, 20, 682-737 Inorganic and hybrid nanofibrous materials templated with organogelators. Llusar, M.; Sanchez, C., Chem.
Mater., 2008, 20, 782-820 Photonic and nanobiophotonic properties of luminescent lanthanide-doped hybrid organic- inorganic materials.
Escribano, P.; Julian-Lopez, B.; Planelles-Arago, J.; et al., J. Mater. Chem., 2008, 18, 23-40 Biomimetism and bioinspiration as tools for the design of innovative materials and systems. Sanchez, C; Arribart,
H.; Guille, M. M. G., Nature Mater., 2005, 4, 277-288
PLENARY LECTURES 43
PL3 Inorganic nanocrystals as functional building units for composites
Tito Trindade* Department of Chemistry-CICECO, Aveiro Institute of Nanotechnology,
University of Aveiro, 3810-193 Aveiro, Portugal *[email protected]
Among the diversity of nanomaterials available nowadays, this lecture will focus on the design of functional nanocomposites containing inorganic phases. In order to prepare these composites, the general approach followed in our research group merges concepts from inorganic synthesis and colloidal chemistry. Thus colloidal inorganic nanocrystals and metal complexes will be presented here as functional compounds that confer specific properties to composite materials obtained by diverse chemical strategies. First, organically capped metal nanocrystals will be described as adequate fillers to produce nanocomposites based on synthetic polymers, while hydrophilic nanoparticles will be presented as convenient fillers to produce biocomposites of natural matrices. The second part of the presentation will discuss the synthesis of hybrid silica particles containing inorganic compounds, such as metal complexes and metal oxides, aiming to confer specific functionalities to the final nanoparticles. Selected examples of materials prepared by the strategies mentioned above will illustrate their interest for biological (e.g. clinical diagnostics) and environmental (e.g. water purification) applications.
Figure caption: From inorganic nanocrystals to composites
The author thanks Fundação para a Ciência e Tecnologia (PTDC/CTM-NAN/120668/2010 and Pest-C/CTM/LA0011/2011), FSE and POPH for funding.
INVITED LECTURES
INVITED LECTURES 47
I1 Biomolecular hydrogels – nature's playground for supramolecular chemistry
and physics Ralf P. Richter*
CIC biomaGUNE, Biosurfaces Unit, Donostia - San Sebastian, Spain; J. Fourier Univeristy, Department of Molecular Chemistry, Grenoble, France; Max Planck Institute for Intelligent Systems, Stuttgart,
Germany *[email protected]
Nature has evolved complex materials that are exquisitely designed to perform specific functions. Certain proteins and glycans self-organize in vivo into soft and dynamic, strongly hydrated gel-like matrices. Illustrative examples of such biomolecular hydrogels are cartilage or mucus. Even though biomolecular hydrogels are ubiquitous in living organisms and fulfill fundamental biological tasks, we have today a very limited understanding of their internal organization, and how they function. The main reason is that this type of assemblies is difficult to study with conventional biochemical methods.
In order to study biomolecular hydrogels directly on the supramolecular level, we have developed an unconventional approach that draws on knowledge from several scientific disciplines. Exploiting surface science tools, we tailor-make model systems by directed self-assembly of purified components on solid supports. With a toolbox of biophysical characterization techniques, including QCM-D, ellipsometry, AFM and RICM, these model films can be investigated quantitatively and in great detail. The experimental data, combined with polymer theory, allow us to develop a better understanding of the relationship between the supramolecular organization and dynamics of biomolecular hydrogels, their physico-chemical properties and their biological function.
To illustrate this concept, I will present a few examples of our recent research. They relate to (i) a nanoscopic protein hydrogel inside living cells that is responsible for the regulation of macromolecular transport into and out of the nucleus [1,2], and (ii) microscopic hydrogel-like assemblies that are made from the polysaccharide hyaluronan and hyaluronan-binding proteins and that are involved in various physiopathological process such as inflammation, fertilization, cancer progression and immune response [3-5]. Our results may ultimately prove useful for the development of novel bioinspired devices, such as size and species selective filtration devices, or advanced biosensors, and for the development of novel diagnostic or therapeutic methods.
Acknowledgements: This work was supported by the Spanish Ministry of Economy and Competitiveness (refs. RYC2009-04275 and MAT2011-24306), the Department of Industry of the Basque Government, the German Federal Ministry of Education and Research (ref. 0315157) and the European Research Council (Starting Grant, ref. 306435).
[1] Eisele, N. B.; Frey, S.; Piehler, J.; Görlich, D.; Richter, R. P. EMBO Rep. 2010, 11, 366-372. [2] Eisele, N. B.; Andersson, F. I.; Frey, S.; Richter, R. P. Biomacromolecules 2012, 13, 2322-2332. [3] Richter, R. P.; Hock, K. K.; Burkhartsmeyer, J.; Boehm, H.; Bingen, P.; Wang, G.; Steinmetz, N. F.;
Evans, D. J.; Spatz, J. P. J. Am. Chem. Soc. 2007, 127, 5306-5307. [4] Baranova, N. S.; Nilebäck, E.; Haller, F. M.; Briggs, D. C.; Svedhem, S.; Day, A. J.; Richter, R. P. J.
Biol. Chem. 2011, 286, 25675-25686. [5] Attili, S.; Borisov, O. V.; Richter, R. P. Biomacromolecules 2012, 13, 1466-1477.
INVITED LECTURES 48
I2 Biosurfactants: Powerful Tools in Microbial Enhanced Oil Recovery
Lígia R. Rodrigues1,*, Eduardo J. Gudiña1 and J. A. Teixeira1
1IBB – Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, University of Minho, Braga, Portugal.
Currently, oil represents a crucial source of energy and one of the main drivers of the World economy. Its recovery involves a primary phase that uses the natural pressure drive of the reservoir to produce oil and gas; and a secondary phase that comprises the stimulation of oil wells by injecting fluids to improve the flow of oil and gas to the well-head. However, after these two phases, up to two-thirds of the original oil in place still remains in the reservoir [1]. This poor recovery is due to the low permeability of some reservoirs, the high viscosity of the residual oil limiting its mobility, and the high interfacial tension between the hydrocarbon and aqueous phases which results in high capillary forces that retain the oil in small pores with the reservoir [2]. Therefore, extracting the maximum amount of oil from mature reservoirs is a major challenge of the oil industry. Recovering the entrapped oil involves the use of expensive chemical and thermal tertiary processes. Chemical processes include the use of surfactants, polymers, acids, gases and solvents [1]. These chemicals have distinct roles in the recovery processes, such as the decrease of interfacial tension between oil-water and oil-rock interfaces, thus decreasing capillary forces and altering the wettability of the reservoir rock (surfactants); the increase of water viscosity in flooding operations and the plugging of oil-depleted zones (polymers); the increase of permeability through the porous network (acids); the decrease of oil viscosity and promotion of its flow (gases and solvents). Microbial Enhanced Oil Recovery (MEOR) is an alternative tertiary oil recovery process, with less costs and lower impact on the environment, in which microbial metabolites (biomass, biopolymers, gases, acids, solvents, enzymes and biosurfactants) are used to improve the oil recovery from mature reservoirs [1]. Biosurfactants are a heterogeneous group of surface-active molecules produced by microbes with both hydrophilic and hydrophobic domains, which allow them to partition at the interface between fluid phases with different degrees of polarity, reducing surface and interfacial tensions. The most popular biosurfactants are the lipopeptides (from Bacillus species) and the rhamnolipids (from Pseudomonas species) [3-5]. These compounds can efficiently replace synthetic surfactants in oil recovery operations due to their specific activity, low toxicity, high biodegradability and effectiveness under extreme operational conditions. Two main strategies can be adopted for the use of biosurfactants in enhanced oil recovery. Biosurfactants can be produced ex situ and subsequently injected into the reservoir; or they can be produced in situ by indigenous or injected microorganisms, stimulated by the addition of selected nutrients into the well. The first strategy is expensive due to the capital required for bioreactor operation, product purification and introduction into oil containing rocks; while the second option is more favorable from an economic point of view, but requires the use of microorganisms capable of producing sufficient amounts of biosurfactant within the reservoir [4]. In our group, several suitable microorganisms for MEOR applications have been isolated from crude oil samples and screened for biosurfactant production and ability to degrade heavy oil fractions. These have been further characterized and used in bench-scale models that simulate the common oil recovery operations.
Acknowledgements: This work was supported by PARTEX OIL AND GAS.
[1] Brown, L. R., Curr. Opin. Microbiol., 2010, 13, 316-320. [2] Sen, R., Prog. Energy Combust. Sci., 2008, 34, 714-724. [3] Simpson, D. R.; Natraj, N. R.; McInerney, M.J.; Duncan, K. E., Appl. Microbiol. Biotecnol., 2011, 91, 1083-1093. [4] Gudiña, E. J.; Pereira, J. F. B.; Rodrigues, L. R.; Coutinho, J. A. P.; Teixeira, J. A., Int. Biodeterior. Biodegrad.,
2012, 68, 56-64. [5] Pereira, J. F. B; Gudiña, E. J.; Dória, M. L.; Domingues, M. R.; Rodrigues, L. R.; Teixeira, J. A.; Coutinho, J. A.
P., Eur. J. Mass Spectrom., 2012, 18, 399-406.
INVITED LECTURES 49
I3 Effect of charge mobility and chain length on the adsorption of poly-acids on
oppositely charged nanoparticles. A Monte Carlo simulation Rita S. Dias*
Department of Physics, Norwegian University of Science and Technology, Trondheim, Norway. *[email protected]
Systems comprising of nanoparticles and oppositely charged polyelectrolytes have a great technological interest, being major components in formulations used in pharmaceutical, food, cosmetics, detergents, and paint industries. The stability of colloidal suspensions and the interaction of its constituents are important issues in formulations, and a large effort has been made to understand how the properties of each individual component affect the overall characteristics of the formulations.
Within the class of polyelectrolytes, weak polyelectrolytes are very interesting since their properties can be tunned resorting to pH variations. An additional characteristic of weak polyelectrolytes is the fact that protons can migrate along the chains, between different chains, and between the medium and the polyions [1]. It has been shown, using experimental and theoretical tools, that the mobility of charges in many different systems enhances the interaction between oppositely charged species. Examples are the adsorption of DNA [2-4] and proteins [5,6] onto lipid membranes and the interaction between annealed polyacids and micelles [7,8].
In this work we have systematically studied the effect of charge mobility (quenched vs. annealed) on the adsorption of polyacids to a nanoparticle and, additionally, on the interaction between different nanoparticles. Two different architectures were considered for the quenched polyacids, alternating and diblock, and two modes of charge mobility were considered for the annealed polyacids, intra- and inter-chain mobility. The effect of polyacid chain length was also evaluated.
Figure caption: Left: Distribution of the absolute value of the charge along the polyacid chains for a system with 30 segments, a charge fraction of 0.5, and intra-chain charge mobility in the presence (full curve) and absence (dashed curve) of a nanoparticle. Right: Positioning maps of the adsorbed negatively charged (left-hand side) and neutral (right-hand side) segments of the polyacids on the facing sides of the nanoparticles, placed at a separation of 1 Å. Middle: Representative snapshot.
[1] Srivastava, D. K.; Wang, S.; Peterson, K. L. Biochemistry 2007, 36, 6359-6366. [2] Maier, B.; Radler, J. O. Macromolecules 2000, 33, 7185-7194. [3] Dias, R. S.; Pais, A. A. C. C.; Linse, P.; Miguel, M. G.; Lindman, B. J. Phys. Chem. B 2005, 109, 11781-11788. [4] Dias, R. S.; Pais, A. A. C. C. J. Phys. Chem. B 2012, 116, 9246-9254. [5] Denisov, G.; Wanaski, S.; Luan, P.; Glaser, M.; McLaughlin, S. Biophys. J. 1998, 74, 731-744. [6] Dias, R. S.; Linse, P. Biophys. J. 2008, 94, 3760-3768. [7] Norrman, J.; Lynch, I.; Piculell, L. J. Phys. Chem. B 2007, 111, 8402-8410. [8] Ulrich, S.; Seijo, M.; Languecir, A.; Stoll, S. J. Phys. Chem. B 1997, 110, 20954-20964.
INVITED LECTURES 50
I4 The fluctuation theorem in dense colloids: A simulation study
Antonio M. Puertas*
Group of complex fluids physcis, Applied Physics, Universidad de Almeria, 04120 Almeria, SPAIN *[email protected]
The fluctuation theorem (FT) gives the distribution of work performed by an external forcing in microscopic dissipative systems (e.g. Brownian particles) [1]. Interestingly, the distribution extends to negative works, i.e. the system exerts work onto the external forcing, violating the Second Law of Thermodynamics, although the maximum work is always in positive work. This also implies a distribution of the entropy, which also extends to negative values. The standard Second Law of Thermodynamics is recovered by taking large systems and time intervals. In colloids, experiments and simulations have demonstrated the validity of the FT by dragging a single particle through a viscous medium.
In this work, I will present simulations of a dense system of quasi-hard colloids where a tracer of the same size as the bath particles is trapped in a harmonic potential and dragged through the system at a constant velocity. The distribution of work done by the harmonic trap is calculated, and studied with effective parameters for the colloidal bath, namely the system viscosity and temperature of the colloidal bath, which can be also determined from the steady state position distribution of the tracer inside the trap. The necessity of effective parameters reveals the complex dynamics of the tracer, which is also studied in detail, using tracer position correlation functions. The results for the effective parameters and dynamics of the tracer are compared with experiments, confirming the general results obtained by the simulations. Different types of forcings can be used, providing qualitatively the same results.
Figure caption: Slice of the three dimensional system containing the tracer (marked in red), moving to the right.
In conclusion, we show how microrheology experiments or simulations can provide measurements of the viscosity of a colloidal system, but also the dynamics of the tracer reflects the dynamics of the bath, which becomes increasingly complex as the glass transition is approached.
[1] Evans, D. J.; Cohen, E. G. D.; Morris, G. P. Phys. Rev. Lett., 1993, 71, 2401.
INVITED LECTURES 51
I5 The Ion Specificity on Colloidal Systems
Delfi Bastos-González1,*, Leonor Pérez-Fuentes1, Carlos Drummond2 and Jordi Faraudo3
1Grupo de Física de Fluidos y Biocoloides, Departamento de Física Aplicada, Facultad de Ciencias, Universidad de Granada, Granada 18071 (Spain).
2CNRS, Centre de Recherche Paul Pascal (CRPP),Bordeaux, France. 3Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus de la UAB, E-08193 Bellaterra,
Barcelona, Spain *[email protected]
In this contribution, I am going to present the current state of the art of Hofmeister effects or ion specificity on aqueous colloidal interfaces. I will specially highlight our contributions in this research field, analyzing the most significant published data and also some new experiments and simulations will be discussed.
It is widely known that different monovalent ions are able to specifically modify a broad range of interfacial phenomena from surface tensions to colloidal stability by means of accumulation or exclusion of the ions from the interfaces that cannot be explained just by considering electrostatic interactions. These ionic specificities are commonly known as Hofmeister effects [1]. They are universal phenomena present in biology, biochemistry, chemistry and chemical engineering, colloid and surface science, and, even though they were observed for the first time in 1888, their origin is still a matter of debate. In addition, with very few exceptions, cations and anions consistently order with the same sequence, called the Hofmeister series, regardless of the property studied. It is most recently accepted that to explain ion specificity in Colloidal Systems is mandatory to consider not only the nature of the ions but also the nature of the surfaces that interact with the ions [2-5]. Different results coming from experiments and simulations show that the interaction of monovalent ions with interfaces is dominated by solvation thermodynamics, this is the chaotropic/kosmotropic character of ions and the hydrophobic/hydrophilic character of the surfaces [6,7]. These conclusions are further emphasize when soft colloidal systems instead of hard particles are used to analyze Hofmeister effects [8,9].
Acknowledgements: The authors acknowledge the financial support from projects MAT2009-13155-C04-02, MAT2012-3670-C04-02 (Ministerio de Educación y Cultura (Spain)), P10-CTS-6270 (Junta de Andalucía) and CEIBioTic 20F12/16.
[1] Hofmeister, F., Arch.Pathol. 1888, 24, 247. [2] Kunz, W., Curr. Opin. Colloid Interface, 2010, 15, 34. [3] López-León, T.; Santander-Ortega, M. J.; Ortega-Vinuesa, J. L.; Bastos-González, D., J. Phys. Chem.
C. 2008, 112, 16060. [4] López-León, T.; López-López, J. M.; Odriozola, G.; Bastos-González, D.; Ortega-Vinuesa, J. L., Soft
Matter,2010, 6, 1114. [5] Schiwerz, N., Horinek, D., Netz, R. R., Langmuir, 2013, 29, 2602 [6] Peula-García, J. M.; Ortega-Vinuesa, J.L.; Bastos-González, D., J. Phys. Chem. C. 2010, 114, 11133. [7] Calero, C.; Faraudo, J.; Bastos-González, D., J. Am. Chem. Soc. 2011, 133, 15025. [8] López-León, T.; Elaïssari, A.; Ortega-Vinuesa, J. L.; Bastos-González, D., ChemPhysChem. 2007, 8,
148. [9] Pérez-Fuentes, L..; Drummond, C.;Bastos-González, D. Ion Specificity on pNIPAM microgels: An
AFM study. Under preparation.
INVITED LECTURES 52
I6 Electron dynamics in nanostructured metal-oxide films: novel routes towards
clean energy technologies Juan A. Anta*
Department of Physical, Chemical and Natural Systems, Universidad Pablo de Olavide, 41013 Sevilla, Spain
Nanostructured films of metal-oxide semiconductors are the focus of intensive research nowadays due to their applications in the current quest for new sources of clean energy. Metal-oxides like TiO2 and ZnO can be used to make efficient photoanodes for photoelectrochemical solar cells and nanostructured substrates for photocatalytic production of non-polluting fuels. ZnO, the first oxide utilized to make dye-sensitized solar cells, exhibits an unique combination of potentially interesting properties such as high bulk electron mobility and probably the richest variety of nanostructures based on a very wide range of synthesis routes. In these applications electron transport through the nanostructure is crucial to achieve a good photon-to-electron quantum efficiency. In this talk the current knowledge of the electron transport mechanisms that take place in these systems is reviewed, highlighting the influence of energy and morphological disorder on the efficacy of the transport process. A special connection is made between the specificity of the electron transport in these systems and their applications in solar cells and photocatalytic devices.
INVITED LECTURES 53
I7 Nanostructured surfaces of conducting polymers and applications in organic
photovoltaic cells Ana Charas*
Instituto de Telecomunicações, Instituto Superior Técnico, Lisbon, P-1049-001, Portugal, *[email protected]
Organic photovoltaic cells (OPVs) using conjugated polymers as active components represent a potential low-cost alternative to silicon-based solar cells, due to involving lower manufacturing costs which are related to the capability of depositing the organic (active) layer from liquid solutions, through printing technologies. Moreover, due to the structural properties of the utilized polymers, lighter, semitransparent, and even flexible devices may be fabricated. This allows conceiving new and appealing commercial applications, as vertical or curved power-generating windows. However, OPVs still suffer from low values of energy conversion efficiency and poor device stability. Both the chemical structure of the organic materials and the morphology of the organic layer play a crucial role in the performance of such devices. Most efficient systems are based on a nanostructured interpenetrating network comprising a conjugated polymer, acting as an electron donor, and a fullerene derivative as an electron-accepting component. In this communication, it is presented an approach to tailor the morphology of the organic layer, while enhancing its stability, through the use of cross-linkable conjugated polymers [1-3]. We have synthesized several new photo-active cross-linkable polymers, either poly(9,9-dialkylfluorene)s or poly(3-alkyl-thiophene)s derivatives, whose cross-linking ability derives from oxetane moieties as end-groups in the polymer side-chains (Figure 1) [1-3]. Oxetane moieties react through cationic ring-opening polymerization leading to an insoluble polymer network. Our approach to reach
nanostructured layers of such polymers takes advantage from the phase separation that occurs during the polymer deposition when blended with polystyrene standards, in solution, by the spin coating technique. The resultant morphologies are controlled by the blend characteristics and the spinning speed of the deposition. Using this approach, we have tailored film morphologies aiming at enhancing photocurrent generation and device stability. Here, an overview of such research work is presented.
Figure caption: Scheme of an organic photovoltaic cell comprising a nanostructured layer of a cross-linked conjugated polymer, as the electron donor, and a soluble fullerene (as the electron acceptor).
Acknowledgements: This work was financed by national funds through FCT – Fundação para a Ciência e a Tecnologia (Portugal) under the projects «PTDC/CTM/111263/2009» and «PTDC/CTM-NAN/1471/2012».
[1] Charas, A.; Ferreira, Q.; Farinhas, J.; Matos, M.; Fonseca, S.; Burrows, H.; Alcácer, L.; Morgado, J., Macromolecules 2009, 42, 7903-7912.
[2] Farinhas, J.; Ferreira, Q.; Di Paolo, R. E.; Alcácer, L.; Morgado, J.; Charas, A.; J. Mater. Chem., 2011, 21, 12511-12519.
[3] Brotas, G.; Farinhas, J.; Ferreira, Q.; Morgado, J.; Charas, A., Synthetic Metals, 2012, 162, 2052-2058.
INVITED LECTURES 54
I8 Functional Hairy Particles and Films via Block Copolymer-Stabilized Emulsion
Polymerization Hans Heuts1,*, Martin Fijten1, Alexandra Muñoz Bonilla2 and Alex van Herk3
1Laboratory of Polymer Materials, Eindhoven University of Technology, The Netherlands. 2Instituto de Ciencia y Tecnología de Polímeros, CSIC, Madrid, Spain.
3Polymer Group, Institute of Chemical and Engineering Sciences, Singapore. *[email protected]
Polymer nanoparticles with functional groups on their outside are receiving an increasing research interest, especially for their potential use in biomedical applications. Instead of "clicking" functional chains onto the particle surface, a commonly used technique at present, we have chosen an ab initio approach in which we already introduce the functional groups at the beginning of the particle synthesis. We do this by using block copolymer surfactants as stabilizers in emulsion polymerization and so produce functional hairy particles. With the desired functionality present in the hydrophilic block, it will end up in the outer shell, i.e., the "hairy layer", of the particles.
Using this approach, it should also be possible to control the number of "hairs" per particle, as (depending on the respective block lengths) the block copolymer micelles can act as a polymer seed for emulsion polymerization, resulting in a one-to-one conversion of micelles into particles.[1] If, additionally, the aggregation number of block copolymers in the micelles is known (and controllable via scaling laws), then the number of blocks per particle is known. Finally, if the block copolymers show sufficient mobility during film formation of the functional latex, it should be possible to create functional surface coatings. This process, which we intend to control completely is schematically shown in Scheme 1.
It is clear that the nature of the hydrophilic block will determine the surface properties of the functional polymer films. In the current presentation we will focus on the results we obtained using four different block copolymer surfactants: one with a cationic hydrophilic block, one with a glycopolymer block,[2] one with the hydrophilic block containing PEG-brushes [3,4] and finally one that consists of two poly(oxazoline) blocks.
Scheme 1.
[1] Burgière, C.; Chassenieux, C.; Charleux, B., Polymer 2003, 44, 509–518. [2] Muñoz-Bonilla, A.; Heuts, J. P. A.; Fernández-García, M., Soft Matter 2011, 7, 2493-2499. [3] Muñoz-Bonilla, A.; Van Herk, A. M.; Heuts, J. P. A., Macromolecules 2010, 43, 2721-2731. [4] Muñoz-Bonilla, A.; Ali, S. I.; Del Campo, A.; Fernández-García, M.; Van Herk, A. M.; Heuts, J. P.
A., Macromolecules 2011, 44, 4282-4290.
INVITED LECTURES 55
I9 Nanosized particles: Beyond a simple tool to fight against disease
Pablo Taboada* Grupo de Física de Coloides y Polímeros, Facultad de Física, Universidad de Santiago de Compostela,
Campus Vida 15782, Santiago de Compostela, Spain *[email protected]
Since last decade a exponential interest in the study of the properties of inorganic and organic nanosized structures has emerged for their intended use in biomedical applications. Nanosized particles display properties that are mainly determined not only by their size, morphology and composition, but also by the surrounding physico-chemical environment where they are immersed. Their size is rather similar to that of many biomolecules present in biological fluids such as proteins, hormones, lipids, sugars or of cellular substructures, amongst others. This similarity facilitates their mutual interactions, enabling the monitorization, induction, modification and/or manipulation of biological states. In fact, the ability of nanotechnology to shape matter and its composition on the scale of molecules and supramolecular aggregates open the door to achieve a full knowledge and a controlled regulation of many different biological processes, which can be directly applied to the development of a new generation of diagnostic imaging agents and therapeutic compounds for detecting and treating diseases and, in particular, cancer. But perhaps more important, the combined use of the tools provided by nanotechology together with clever combinations of different nanomaterials are allowing researchers to create new external/internal-stimuli responsive nanosized platforms that may contain drug compounds designed to kill tumours on demand, with targeting ligands designed to only interact with malignancies, and imaging contrast agents designed to light up even the earliest stage of cancers, all this giving rise to a new field known as theranostics (therapy + diagnostics). Also, a description of cancers in molecular terms are likely to improve the way in which malignancy are detected, identified, monitored, and treated and for that, nanosized particles, which allow to address molecular structure thanks to their nanometer-size, may be specially useful. However, it is necessary to bear in mind that there are still some controversial points which need a deeper understanding before a definitive clinical application can take place, as the elimination of any concern about potential partcile nanotoxicity, or the achievement of a full knowledge of the mechanisms underlying particle-biomolecules and particle-cell mutual interactions.
In this talk, several examples about the role played by nanosized particles in the induction/modification of cellular and/or biomolecular responses and how different configurations of these kind of nanomaterials can lead to the construction of really effective multifunctional theranostic nanodevices able to possses simultaneous capabilities of both multi-imaging diagnostics and multi-therapeutics to fight gainst cancer will be presented. A special emphasis will be devoted to the work my research group is developing in this field.
INVITED LECTURES 56
I10 Towards an integrated plasmonic platform
for early cancer detection R. Quidant1,2,*
1 ICFO-Institut de Ciencies Photoniques, Mediterranean technology Park, Castelldefels (Barcelona), Spain
2 ICREA-Institució Catalana de Recerca i Estudis Avançats, Passeig Lluís Companys, Barcelona, Spain *[email protected]
Nanoscale control of plasmonic fields in engineered metal nanostructures offers unique opportunities to boost the interaction of light with tiny amount of matter, down to the single molecule level. In particular, such enhanced interaction can strongly benefit to the detection of small amounts of molecules, such as proteins for diagnosis purposes.
In the present paper we present recent advances obtained within the framework of SPEDOC [1], European initiative that aims at combining the latest advances of nanoplasmonics, microfluidics and oncology to develop an integrated platform for early cancer detection and treatment monitoring. In particular, we will discuss different plasmon-based strategies developed within SPEDOC for the detection of low concentration of cancer markers in blood.
[1] www.spedoc.eu
CLOSING TALKS
CLOSING TALKS 59
CT1 Synthesis of Nano-coral like colloidal particles via water-in-oil miniemulsion
R. Ladj1,2, Y. Mounier2, R. Le-Dantec2, H. Fessi1 and A. Elaissari1,* 1University of Lyon, F- 69622, Lyon, France; University of Lyon-1, Villeurbanne, CNRS, UMR 5007, LAGEP-CPE-308G, 43 bd. du 11 Nov.1918, F-69622, Villeurbanne, France.
2Université de Savoie, Laboratoire SYMME, BP 80439, 74944 Annecy le Vieux Cedex, France. *[email protected]
Hybrid nanoparticles are one of the most important classes of colloidal materials due to the current interest in biomedical field, supported chemistry and physical area. These hybrid materials bearing intrinsic physical properties can be used in-vitro biomedical imaging. Iron iodate nanocrystals having a noncentrosymmetric structure can be used as nonresonant nonlinear optical probes for bioimaging applications in vitro by use of the second order processes of second harmonic. These nonresonant processes provide advantages above and beyond traditional two photon bioimaging: (i) no photobleaching effect; (ii) coherent and stable signals with good flexibility in the choice of excitation wavelength; and (iii) no heat dissipation into the cells, ensuring longer cell viability and ultimately longer imaging times. Then, the aims of this work if to prepare iron iodate nanocrystals for in vitro biomedical imaging. To target such object, submicron nanoparticles should be prepared and then encapsulated in order to induce biocompatibility (i.e. non cytotoxicity effect).
Iron iodate colloid nanoparticles have been prepared through mixing two water-in-oil miniemulsions of iron nitrate and iodic acid salt to obtain water-in-oil miniemulsion of iron iodate. The nanocrystals were obtained via precipitation reaction of IO3
- and Fe3+ ions inside aqueous nanodroplets (i.e. nanoreactors). The water-droplet emulsions were prepared using span 80 as surfactant below CMC in cyclohexane (as continuous phase). The fragmentation was performed using ultrasound emulsification. The physicochemical properties of the water droplets containing iron iodate nanoparticles are characterized by TEM and SEM to examine the morphology of particles, DRX analysis to study the noncentrosymmetric crystalline structure, dynamic light scattering for particle size analysis, potential zeta for surface properties and infrared analysis. In addition, the cytotoxicity and second-harmonic imaging of nanoparticles were investigated via in-vitro study.
natural coral nanocorale like particles
Acknowledgements: This research has been partially conducted under the European FP7 Research Project NAMDIATREAM (NMP4-LA-2010-246479, http://www.namdiatream.eu) and INTERREG IV France-Switzerland NAOMI
CLOSING TALKS 60
CT2 Hydrophobic Interactions Modulate Self-assembly of Gold Nanoparticles
Marek Grzelczak 1,2,*, Ana Sánchez-Iglesias 1, Thomas Altantzi 3, Bart Goris 3, Jorge Perez-Juste 4, Sara Bals 3 , Gustaaf Van Tendeloo 3, Stephen H. Donaldson Jr.5, Bradley F.
Chmelka5, Jacob N. Israelachvili 5, and Luis M. Liz-Marzán 1,2,4,* 1CIC biomaGUNE, Spain; 2Ikerbasque, Basque Foundation for Science, Spain;.
3University of Antwerp, Belgium; 4Universidade de Vigo, Spain; 5University of California, USA *[email protected], *[email protected]
Hydrophobic interactions constitute one of the most important types of non-specific interactions in biological systems, which emerge when water molecules rearrange as two hydrophobic species come close to each other. Prediction of hydrophobic interactions at the level of nanoparticles (Brownian objects) remains challenging, because of uncontrolled diffusive motion of the particles. We show that polystyrene (PS)-stabilized spherical gold nanoparticles dispersed in tetrahydrofuran (THF) can form monodisersed aggregates upon addition of water, which is a bad solvent for PS (Scheme 1).[1] The growth of the clusters can be quenched by addition of a polymeric surfactant comprising hydrophobic (polystyrene) and hydrophilic (poly-acrylic acid) blocks (PS-b-PAA). While micellization of the polymeric surfactant allows for sequestration of clusters inside the hydrophobic core, the hydrophilic outer surface of the micelles (comprising the PAA blocks) ensures stability in polar solvents.
Figure caption: Three-dimensional self-assembly of polystyrene-coated gold nanoparticles. Dispersion of
polystyrene-coated gold nanoparticles in THF undergoes aggregation in the presence of water. The addition of polymeric surfactant (PS-b-PAA) suppresses further aggregation of the nanoparticles,
producing stable clusters.
[1] Sánchez-Iglesias, A.; Grzelczak, M.; Altantzis, T.; Goris, B.; Pérez-Juste, J.; Bals, S.; Van Tendeloo, G.; Donaldson, S. H.; Chmelka, B. F.; Israelachvili, J. N.; Liz-Marzán, L. M., ACS Nano 2012, 6, 11059–11065.
CLOSING TALKS 61
CT3 Phase diagram of Magnetic filaments in bulk and near surfaces
Joan J. Cerdà1,*, Pedro A. Sánchez2, C. Holm2 and Tomàs Sintes1 1Instituto de Física Interdisiciplinar y Sistemas Complejos - IFISC (CSIC-UIB), Majorca, Spain.
2Institute for Computational Physics- ICP (Universtität Stuttgart), Stuttgart, Germany *[email protected]
Artificial magnetic filaments can be obtained by mutually linking magnetic colloids to form a chain. These magnetic chains represent the equivalent to magnetic polymers but at supra-molecular scale. In difference to one-dimensional chemical magnetic polymers which only manifest their magnetic properties at T<100K, magnetic filaments can retain their magnetism at room temperature and zero field. In this contribution we present the results of our previous studies [1, 2, 3] on the equilibrium conformations of flexible and semiflexible magnetic filaments in different physical environments of relevance for forthcoming applications. In particular, we focus on the determination of the phase diagram at zero field for magnetic filaments which monomers exhibit short-range LJ attractive interactions (Stockmayer polymers, i.e. filaments in poor solvent conditions) in the limit of strong dilution, as well as filaments in good solvent conditions. We study the cases of magnetic chains in bulk (see figure 1) and near an attractive surface. We find that the phase diagrams of magnetic systems exhibit a rich variety of new phases when compared with non-magnetic chains in similar environments. The emerging interest in this relatively novel field is due to the fact that magnetic filaments are very appealing from the technological point of view. They can be thought as improved substitutes of current ferrofluids, or as elements for magnetic memories, chemical and pressure nanosensors, micro-propellers, non-permanent photonic crystals, and generation of unique patterns able to provide watermarks to authenticate cards or other documents, to just mention a few.
Figure caption: A tentative phase diagram for magnetic filaments of length N=100, and a dipole moment per
monomer of fixed strength μ²=5. Acknowledgements: We thank the projects FISICOS (FIS2007-60327), GRID-CSIC and BwGrid founded by the Spanish MICNN and the ERDF, respectively. [1] Sánchez, P. A.; Cerdà, J. J.; Ballenegger, V.; Sintes, T.; Holm, C. Soft Matter, 2011, 7, 1809 [2] Cerdà, J. J.; Sánchez, P. A.; Holm, C.; Sintes, T. submitted to Soft Matter, arXiv:1302.5897. [3] Sánchez, P. A.; Cerdà, J. J.; Sintes, T.; Holm, C. submitted to JCP, arXiv:1302.5845
CLOSING TALKS 62
CT4 Wetting-induced fluid entrainment and drop emission for driven fluid filaments
I. Pagonabarraga*
Departament de Física Fonamental, Universitat de Barcelona, Carrer Martí i Franqués 1, 08028-Barcelona, Spain
Forced liquid films or filaments detach from the solid they displace on when the contact line cannot follow the motion of the rest of the film under the action of a driving force. The instability onset is sensitive to the equilibrium contact line and different patterns can be promoted by tuning the chemical composition of an heterogeneous solid substrate[1]. I will discuss in this presentation the interplay between equilibrium and dynamic wetting to control the stability of an advancing liquid front. I will describe a theoretical analysis to understand the relevance of the friction at the contact line[2]. For liquid mixtures with large interfacial widths (as is the case for colloid/polymer mixtures) this local friction plays a relevant role in the onset of entrainment of forced thin films. I will also present results of numerical simulations to analyze the onset of entraiment and analyze the drops that are emitted[3]. This study indicates that equilibrium wetting properties of a substrate can be used as an alternative mechanism to emit small drops. The theoretical predictions and the numerical evidence explain experimental results of entrainment in superhydrophobic surfaces and in the instabilities observed on the dynamics of colloid/polymer mixtures in Hele-Shaw cells.
Figure caption: Liquid filaments forced on chemical stripes of prescribed equilibrium contact angle, at varying capillary numbers. Above a characteristic Ca, which depends on the equilibrium contact angle,
drops are emitted.
[1] Ledesma-Aguilar R.; Hernández-Machado, A.; Pagonabarraga, I., Soft Matter, 2011, 7, 6051 [2] Ledesma-Aguilar R.; Hernández-Machado, A.; Pagonabarraga, I., submitted [3] Ledesma-Aguilar R.; Nistal, R.; Hernández-Machado, A.; Pagonabarraga, I., Nature Mater., 2011,
10, 367
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CT5 Non-NIPAM based microgels: Tuning the volume phase transition by
copolymerisation and by particle architecture Thomas Hellweg1,*, Michael Zeiser1 and Bastian Wedel1
1Universität Bielefeld, Fakultät für Chemie Physikaische und Biophysikalische Chemie, Universitätsstr. 25, 33615 Bielefeld, Germany.
Most of the so-called smart microgels studied in the last 20 years were mainly based on poly(N-isopropylacrylamide (PNIPAM). Only a few works used alternative acrylamides like e.g. poly(N-isopropylmethacrylamide) (PNIPMAM) [1].
In our recent work we have shown that especially the use of alternatives to PNIPAM leads to very interesting new properties of the obtained materials [2,3]. An example for the swelling behaviour of the new materials is given in the left part of the figure below, which shows the hydrodynamic radius of core-shell microgels with a shell made of N-n-propylacryalmide and a core of PNIPMAM. These two polymers have a difference in the lower critical solution temperature of about 21 °C. This difference leads to the new swelling properties.
Also statistical copolymers of the same monomers were studied. His approach can be used to continuously tune the phase transition temperature of the obtained materials.
The talk will review these works.
Figure caption: (left) Swelling curve of a PNNPAM-PNIPMAM core-shell system with a core
containing 12.5 mol% crosslinker; (right) SEM image of the same particles.
[1] Berndt I.; Richtering W., Macromolecules, 2003, 36, 8780. [2] Wedel B.; Zeiser M.; Hellweg T., Z. Phys Chem, 2012, 226, 737 [3] Zeiser, M.; Freudensprung, I.; Hellweg, T., Polymer, 2012, 53, 6096
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CT6 Plasmonic Nanoparticles based on Colloid Chemistry
A. Guerrero-Martínez1,* and L. M. Liz-Marzán2
1Departamento de Química Física I, Universidad Complutense, Avda. 20 Complutense s/n, 28040, Madrid, Spain
2BioNanoPlasmonics Laboratory, CIC biomaGUNE, Paseo de Miramón 182, 20009 Donostia - San Sebastián, Spain
Nanoplasmonics can be defined as the science that studies the excitation of surface plasmon resonances on metal nanostructures, and their potential technological applications [1]. Such localized surface plasmons arise from the interaction between light and the conduction electrons in nanostructured metals, yielding bright colors in disperse metal nanoparticles. These colors can be tuned by changing different parameters such as the size, shape, and composition of the particles, but also the dielectric nature of the surroundings [2]. In the case of anisotropic particles, the optical response directly depends on the polarization of the incident light, which allows an additional degree of manipulation [3]. Moreover, these localized surface plasmons give rise to high electric fields at the metallic surface, which can be controlled and amplified from colloidal self-assembly [4]. All these effects open new perspectives for designing new devices with applications in a wide variety of fields.
Acknowledgements: This work has been funded by the European Research Council (ERC Advanced Grant #267867 Plasmaquo). A.G.-M. acknowledges receipt of a Ramón y Cajal Fellowship from the Ministerio de Economía y Competitivdad.
[1] Guerrero-Martínez, A.; Grzelczak, M.; Liz-Marzán, L. M. ACS Nano 2012, 6, 3655. [2] Jain, P. K.; Lee, K. S.; El-Sayed, I. H.; El-Sayed, M. A. J. Phys. Chem. B 2006, 110, 7238. [3] Guerrero-Martínez, A.; Augié, B.; Alonso-Gómez, J. L.; Džoli�, Z.; Gómez-Graña, S.; Žini�, M.;
Cid, M. M.; Liz-Marzán, L. M. Angew. Chem. Int. Ed. 2011, 50, 5499. [4] Guerrero-Martínez, A.; Pérez-Juste, J.; Carbó-Argibay, E.; Tardajos, G.; Liz-Marzan, L. M. Angew.
Chem. Int. Ed. 2009, 48, 9484.
CLOSING TALKS 65
CT7 A chemical garden model for the formation mechanism of brinicles
Bruno Escribano1,* 1Basque Center for Applied Mathematics, Bilbao, Spain.
Chemical gardens are a common and well known experiment where hollow tubes grow from a metal salt crystal immersed in a solution of silicate or other anions. The formation process is a combination of filtering and precipitation: a metal-silicate semipermeable membrane coats the crystal and intakes water by filtering it from the silicate solution; the tubes grow by precipitation around a flow of metal solution ejected when the membrane bursts. On the other hand, brinicles are hollow tubes of ice that form when dense, cold brine drains downward from polar ice sheets into sea water at its freeing point. In this case the ice sheet supplies the filtering mechanism by crystallizing water molecules and accumulating concentrated brine in trapped compartments within the ice, a process known as brine rejection. Precipitation occurs when this cold brine is ejected from the ice and comes into contact with the sea water, freezing it around the brine flow and forming a tubular structure. Brinicles are difficult to study because they only grow under polar ice sheets during winter and in calm waters. For this reason their formation mechanism is still not completely understood. However, their possible role in the theories for a cold origin of life [1,2] has attracted recent attention. Here, we use our experience working with chemical gardens [3] and apply it to better understand the formation mechanism of brinicles [4]. In this way we intend to answer some of the open questions regarding brinicle formation, such as: What is the trigger mechanism? How does the brine flow remain constant? How does brine migrate within the ice?
Figure caption: Schematic representation of the brinicle formation process.
[1] Trinks, H.; Schröder, W.; Bierbricher, C. K. Origins Life Evol. Biospheres 2005, 35, 429–445. [2] Bartels-Rausch, T. et al. Rev. Mod. Phys. 2012, 84, 885–944. [3] Cartwright, J. H. E.; Escribano, B.; Sainz-Díaz, C. I.; Stodieck, L. S. Langmuir 2011, 27,
3294–3300. [4] Cartwright, J. H. E.; Escribano, B.; González, D. L.; Sainz-Díaz, C. I.; Tuval, I. Langmuir 2013,
DOI: 10.1021/la40097
ORAL COMMUNICATIONS
NANOPARTICLES: ORGANIC, INORGANIC AND HYBRIDS 69
O1.1 Light-Addressable and Degradable Silica Capsules for Cytosolic Release
S. Carregal-Romero1,2,*, A. Ott,1 and W. J. Parak1 1 Biophotonics department, Institute of Physics and WZMW, Philipps-Universität Marburg, Renthof 7,
35037 Marburg, Germany. 2 Andalusian Center for Nanomedicine and Biotechnology (BIONAND), Andalusian Technological Park.
C/ Severo Ochoa, 35, 29590 Campanillas, Málaga, Spain. *[email protected]
Plasmonic nanoparticles can be used to destroy cancer cells and tumors by applying light. Cancer cells are more sensitive to slight increases of temperature and therefore the relaxation of the electrons that had absorbed light into heat can be used to produce hyperthermia and tumor destruction.[1,2] Applying lower power density of light, similar plasmonic structures can optically trigger the delivery of certain drugs and biofunctional molecules from their surface or from microscopic structures acting as carrier systems.[3,4] Light-responsive polyelectrolyte capsules have been used as efficient carrier systems to deliver into the cytosol different kinds of proteins and molecules such mRNA by keeping intact their biological activity.[4] In this work, we describe the synthesis of silica capsules that depending on the composition can deliver functional molecules through degradation or light-triggered release. The two different release mechanisms of cargo molecules in vitro will be discussed and compared with the aforementioned polyelectrolyte capsules.
Figure caption: Cytosolic release of pH sensor dye from a silica capsule.
[1] Qin, Z.; Bischof, J. C. Chem. Soc. Rev. 2011. [2] O'Neal, D. P.; Hirsch, L. R.; Halas, N. J.; Payne, J. D.; West, J. L. Cancer Letters 2004, 209, 171. [3] Huschka, R.; Barhoumi, A.; Liu, Q.; Roth, J. A.; Ji, L.; Halas, N. J. ACS Nano 2012, 6, 7681. [4] Ochs, M.; Carregal-Romero, S.; Rejman, J.; Braeckmans, K.; De Smedt, S. C.; Parak, W. J. Angew.
Chem., Int. Ed. 2013, 52, 695.
NANOPARTICLES: ORGANIC, INORGANIC AND HYBRIDS 70
O1.2 Silicon Colloids with a strong magnetic response below 1.5 micrometers region
Lei Shi1,2, Roberto Fenollosa1,2*, Francisco Meseguer1,2 1Consejo Superior de Investigaciones Científicas (Unidad Asociada Instituto de Ciencia de Materiales
de Madrid (CSIC) – Universidad Politécnica de Valencia) 2Centro de Tecnologías Físicas, Edificio 8B Bloque K, Universidad Politécnica de Valencia,
Avda. Tarongers s/n, Valencia, Spain *[email protected]
It is generally accepted that the magnetic response of materials at optical frequency values is completely negligible. The recent discovery of Metamaterials (MMs) has broken this traditional understanding, since both the electric and the magnetic field are key ingredients in MMs [1]. Although, MMs have shown their potential for molding light matter interaction, unsolved problems remain that prevent their use in practical applications. One challenge concerns the intrinsic losses in the optical range of noble metals used for MMs processing [2]. One potential way to circumvent this obstacle concerns using high refractive index value dielectric structures, which may show strong magnetic and electric resonances [3]. Particularly, Mie resonances of high refractive index optical nanocavities may open a new route to realize low loss isotropic metamaterials. Here we report on the synthesis and the optical properties of silicon colloids based nanocavities with strong magnetic response in the NIR region [4,5]. The transmission and reflection properties of single silicon colloids with size values between 250 nm and 700 nm are reported. Both, experiments and theoretical calculations (Mie theory and the finite difference time domain (FDTD) simulations) clearly show that single submicron silicon nanocavities support well defined magnetic resonances in NIR region at wavelength values up to six times larger than the cavity radius.
[1] Soukoulis, C. M.; Wegener, M., Nat. Photon., 2011, 5, 523. [2] Zheludev, N.I., Science, 2010, 328, 582. [3] Popa, B.; Cummer, S. A., Phys. Rev. Lett., 2008, 100, 207401. [4] Shi, L.; Tuzer, T. U.; Fenollosa, R.; Meseguer, F., Adv. Mater., 2012, 24, 5934. [5] Shi, L.; Harris, J.; Fenollosa, R.; Rodriguez, I.; Lu, X.; Korgel, B. A.; Meseguer, F. (submitted)
NANOPARTICLES: ORGANIC, INORGANIC AND HYBRIDS 71
O1.3 Resizing of colloidal gold nanorods using aqueous K2S2O8 and morphological
probing by SERS Sara Fateixa1,*, Tito Trindade1
1Department of Chemistry-CICECO, Aveiro Institute of Nanotechnology, University of Aveiro, Portugal
Surface Enhanced Raman Scattering (SERS) is a vibrational spectroscopic technique that provides valuable information about the nature and orientation of molecular species adsorbed at metal surfaces and on the adsorbate–metal interaction mechanism 1, 2 . On the other hand, the morphological characteristics of metal nanoparticles used as SERS substrates have strong influence on the Raman signal 3, 4 . In this report we present the use of SERS as a method to monitor the resizing of colloidal AuNRs treated with aqueous K2S2O8, at room temperature.
Hence, these SERS studies have been performed using colloidal Au nanorods (NRs) collected at different stages of oxidation, using diluted sodium diethyldithiocarbamate as molecular probe, and using the NIR excitation line (1064 nm). The results showed that the SERS sensitivity of the Au NRs substrates decreased with the decrease of the particle A.R., as estimated on the basis of analytical enhancement factors. We will discuss this approach as an alternative to probe in situ morphological changes on Au NRs that are routinely performed by measuring the respective VIS/NIR spectra and whose characteristics are well known to vary with particle shape and size.
Figure caption: Digital photographs of colloidal Au NRs submitted to aqueous K2S2O8, at variable
reaction times.
Acknowledgements: S. Fateixa thanks Fundação para a Ciência e Tecnologia (FCT/FEDER) for the grant SFRH/BD/66460/2009. The authors thank FCT (PTDC/CTM-NAN/120668/2010; Pest-C/CTM/LA0011/2011), FSE and POPH for funding.
[1] Kneipp, J.; Kneipp, H.; Kneipp, K., Chem. Soc. Rev. 2008, 37, 1052–1060. [2] Sharma, B.; Frontiera, R. R.; Henry, A.; Ringe, E.; Van Duyne, R. P., Materials Today 2012, 15, 16-
25. [3] Orendorff, C. J.; Gole, A.; Sau, T. K.; Murphy, C. J., Anal. Chem. 2005, 77, 3261-3266. [4] Link, S.; Mohamed, M. B.; El-Sayed, M. A., J. Phys. Chem. B 1999, 103, 3073-3077.
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O1.4 Organized plasmonic clusters with high coordination number and extraordinary
SERS enhancement Nicolas Pazos-Perez1,*, Claudia Simone Wagner2, Luis M. Liz- Marzan3, F. Javier Garcia de
abajo4, Alexander Wittemann2, Ramon Alvarez-Puebla5 and Andreas Fey1
1 Department of Physical Chemistry II, University of Bayreuth, 95440, Bayreuth, Germany. 2 Colloid chemistry, University of Konstanz, 78464 Konstanz, Germany
3 Department of Physical Chemistry, University of Vigo, 36310, Vigo, Spain 4 Instituto de Quimica-Fisica Rocasolano-CSIC, 28006, Madrid, Spain
5 ICREA - Catalan Institution for Research and Advanced Studies, Spain *[email protected]
Noble metal nanoparticles exhibit optical excitations known as surface plasmons. Plasmonic nanoparticles are in the focus of attention because of their interesting electric and optical properties. These types of materials produce a large enhancement of the local light intensity under external illumination. Plasmons are highly related to the specific particle size and shape. There are various synthetic procedures which allow us to fine tune these parameters in order to adjust their plasmonic response. However, the enhancement of the local light increases particularly when particles are arranged in closely spaced configurations. This is due to the formation of hotspots with high electromagnetic fields. Thus, a critical role in the hot spot generation is the inter-particle gap distance.
Controlled assembly using colloidal chemistry is an emerging and promising field for high yield production of metal nanoparticle clusters with small inter-particle gaps. However, most of the reported methods rely on the use of nucleic acids or other organic molecules as linking elements, which yield long separation distances and thus small plasmon coupling. Additionally, only simple clusters such as dimmers and trimmers have been efficiently synthesized. In this work, we report the controlled assembly of gold nanospheres into well-defined nanoparticle clusters with large coordination numbers (up to 7) and high symmetry. We further demonstrate ultrasensitive direct and indirect surface-enhanced Raman scattering (SERS) sensing, thus corroborating the outstanding optical performance of these clusters with robust enhancement factors over 3 orders of magnitude higher than those of single particles.
Figure caption: a) Density gradient separation to obtain a specific population from the initial mixture of clusters. b) SEM micrographs of the different cluster populations obtained after careful fractionation of the corresponding stripes in image (a). c) Representative HR-TEM images of particle dimers and trimers illustrating the small interparticle gaps and cavities generated by this fabrication method.
[1] Pazos-Perez, N., et al., Angew. Chem. Int. Ed., DOI: 10.1002/anie.20120701.
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O1.5 Efficient eco-friendly dye nano-adsorbents based on biopolymer surface
functionalized magnetic nanoparticles Ana L. Daniel-da-Silva*, Ana M. Salgueiro, Bianca Creaney and Tito Trindade
CICECO, Chemistry Department, Aveiro Institute of Nanotechnology, University of Aveiro, 3810-193 Aveiro, Portugal
Organic dyes are present in the effluents of a number of industries (e.g. textile, paper, plastic) and their discharge in water supplies is a matter of concern due their harmful impact on the environment and potential mutagenic and carcinogenic effects. Although a number of materials have been explored as dye adsorbents, the need of more environmentally friendly and low-cost dye adsorbents has raised the attention to biopolymers obtained from renewable resources, such as polysaccharides. [1] This work aims the development of effective dye adsorbents easily separated, based on biopolymer surface modified magnetic nanoparticles. Magnetite (Fe3O4) nanoparticles (NPs) were synthesized using the co-precipitation method. The surface of the magnetic NPs was then modified using -, - and -carrageenan, a family of sulfated polysaccharide extracted from red algae, using two different chemical strategies: the physical immobilization of carrageenan macromolecules onto the surface and the covalent linkage of carrageenan chemically modified with carboxymethyl groups. The composite NPs were tested as adsorbents for the magnetically assisted removal of methylene blue (MB) from aqueous solutions in batch experiments.
Under the experimental conditions used, MB could be recovered fast (< 1 hour) and efficiently, due to electrostatic interaction with the sulphate moieties of carrageenan. Kinetic and equilibrium adsorption studies were carried out. The MB adsorption onto coated NPs has shown an unusual Z-type isotherm which suggests the generation of new adsorbing sites with increasing MB initial concentration. The NPs with carrageenan covalently linked to the surface could be well-regenerated after adsorption and reused at least for 5 cycles of desorption-adsorption without significant decrease of the MB removal capability. These materials displayed MB adsorption capacity higher than other magnetic sorbents previously reported. Thus, carrageenan surface modified magnetite NPs are very promising eco-friendly materials for removing MB from wastewater using magnetic separation.
Acknowledgements: FCT - Fundação para a Ciência e Tecnologia (PTDC/CTM-NAN/120668/2010, Pest-C/CTM/LA0011/2011, SFRH/BPD/66407/2009, FSE and POPH for funding. We thank the RNME (National Electronic Microscopy Network) for TEM facility and to Dr. G. Goya (INA, Zaragoza, Spain) for magnetic measurements.
[1] Crini G., Prog. Polym. Sci. 2005, 30, 38-70.
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O1.6 Microfluidic Self-Assembly of Polymeric Nanoparticles in Aqueous Solutions
and Controlled Drug Delivery Erfan Dashtimoghadam1, Hamid Mirzadeh1, Faramarz Afshar Taromi1, and Bo Nyström2,*
1Department of Polymer Engineering and Color Technology, Amirkabir University of Technology, Tehran, Iran.
2Department of Chemistry, University of Oslo, Oslo, Norway. *[email protected]
An important challenge in the development of polymeric nanoparticles for various applications is precise engineering of the desired physicochemical characteristics in a reproducible manner. This presentation concerns the use of microfluidics to control the local polymer concentration inside polymeric nanoparticles and to produce nanoparticles with a narrow size distribution. A schematic illustration of the device is given in Fig. 1. It is demonstrated that the compactness of nanoparticles based on self-assembled hydrophobically modified chitosan (HMCs) can be dictated with tunable rapid mixing via hydrodynamic flow focused in microfluidic channels [1,2]. It is shown by varying the flow rates, as well as the hydrophobicity of the chitosan biopolymer that the self-assembly behavior of the chains can be controlled by optimizing the size and compactness of the species, along with a more narrow size distribution of the nanoparticles. The size of the particles increased with increasing mixing time, whereas smaller and more compact nanoparticles, comprising of a less number of aggregated chains, are produced for chitosan of higher degrees of hydrophobicity. It was realized that at higher degrees of hydrophobicity and at mixing times longer than the time of aggregation, nanoparticles comprising of almost the same number of hydrophobic stickers were formed.
Furthermore, we explored the effectiveness of microfluidic directed to assemble HMCs and to encapsulate paclitaxel (PTX), a common anticancer drug, which revealed remarkably higher encapsulation efficiency compared to the conventional bulk method. The in-vitro release of PTX from the prepared nanoparticles was evaluated to investigate the effect of compactness of the particles on the release profile. The estimated values of the diffusion coefficient of PTX up to 50% release implied controlled sustainability of the drug release with respect to the compactness of the nanoparticles, and a remarkable improvement compared to the uneven bulk mixing method. These findings indicate a high potential of the microfluidic approach for precise bottom-up controlling physicochemical properties of polymeric nanoparticles for various applications, such as controlled drug delivery systems.
Figure caption: (a) Schematic illustration of the T-shaped microfluidic system used for synthesis of HMCs-based nanoparticles; the HMCs solution stream is hydrodynamically focused with lateral sheath flow of basic
water (pH=9). (b) Fluorescence image of Rhodamine B stream, which is hydrodynamically focused with fluorescein sodium (scale bar 100 �m). (c) AFM image of HMCs-3 nanoparticles synthesized at flow ratio of
0.031, showing a spherical structure (scale bar 200 nm).
[1] Demello, A. J. Nature 2006, 442, 394-402. [2] Whitesides, G. M. Nature 2006, 442, 368-373.
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O1.7 New applications modifying colloidal particles with ion-specific ligands Dorleta Jimenez de Aberasturi1,2,*, Dominik Hühn1, Ricardo Pinedo2, Idoia Ruiz de
Larramendi2, Teofilo Rojo2, Jose Maria Montenegro Martos1, Susana Carregal1, Wolfgang J. Parak1
1Fachbereich Physik and WZMW, Philipps Universität Marburg, Marburg, Germany 2Department of Inorganic Chemistry, UPV/EHU, Bilbao, Spain
Functionalized colloidal nanoparticles have distinctive properties that contribute to promising applications. Moreover, they can introduce new properties to existing materials and thus are a valuable building block for the construction of novel materials. In case we combine ion-selective ligands with particles their functionality can be expanded significantly [1]. By modifying the surface of colloidal particles with ion-specific ligands we can use them for different applications such as sensing [2], imaging [3], and separation [4].
Ion-specific ligands can be directly integrated in the surface of colloidal nanoparticles. Specific bindings of ions to those ligands can be translated in a change of fluorescence when the particles or the ligands are fluorescent [5].or in an increased contrast for imaging if the bound ions are ones such as Gd or In, useful as contrast agents[6]. Hence, fluorescence-based ion sensors or particles as contrast agents can be constructed attaching ion-specific ligands to colloidal nanoparticles.
Alternatively polyelectrolyte capsules as a carrier for ion-specific ligands can also be used, incorporating ion-selective ligands into the capsule cavities and walls. When the walls of the capsules are modified with different nanoparticles, additional properties are provided to the capsules [7-8]. Magnetic microparticles, that include magnetic nanoparticles in their walls, can be used for magnetic separation purposes giving the possibility to extract and separate the ions from solutions that bind to the ligands selectively [9-10].
In summary, due to the technique of combining ion-selective ligands with colloidal particles, new fields of applications are provided for these molecules. [1].Riedinger, A.; Zhang, F.; Dommershausen, F.; Röcker, C.; Brandholt, S.; Nienhaus, G. U.; Koert, U.;
Parak, W. J., Small 2010, 6, 2590-2597. [2] Jimenez de Aberasturi, D.; Montenegro, J. M ; Ruiz de Larramendi, I.; Rojo, T.; Klar, T. A.; Alvarez-
Puebla, R.;. Liz-Marzán, L. M.; Parak, W. J., Chem Mater. 2012, 24,738-745 [3] Ali, Z.; Abbasi, A. Z.; Zhang, F.; Arosio, P.; Lascialfari, A.; Casula, M. F.; Wenk, A.; Kreyling, W.;
Plapper, R.; Seidel, M.; Niessner, R.; Knöll, J.; Seubert, A.; Parak, W. J., Anal. Chem. 2011, 83, 2877-2822.
[4] Manuel Perez. J.; Nature Nanotechnol., 2007, 2, 535 - 536 [5] Ruedas-Rama, M. J.; Orte, A.; Hall, E. A. H.; Alvarez-Pez, J. M.; Talavera, E. M. Chem. Commun. 2011,
47, 2898-2900. [6] Carregal-Romero,S.; Caballero-Díaz, E.; Beqa, L.; Abdelmonem, A.M.; Ochs, M.; Hühn, D.; Suao, B.S.;
Valcarcel, M.; Parak W. J., Anal. Chem., 2013, 6 (in press) [7] Abbasi, A. Z.; Gutiérrez, L.; del Mercato, L. L.; Herranz, F.; et al., J. Mater. Chem. C, 2011,115, 6257-
6264. [8] Ochs, M.; Carregal-Romero, S.; Rejman, J.; Braeckmans, K.; De Smedt, S.C.; Parak, W. J.; Angew. Chem.
Int. Ed. 2013, 52, 695 –699 [9] Colombo, M.; Carregal-Romero, S.; Casula, M. F.; Gutiérrez, L.; Morales, M. P.; Böhm, I. B.; Heverhagen,
J. T.; Prosperi, D.; Parak, W. J., Chem. Soc. Rev., 2012, 41 4306-4334. [10] Uheida, A.; Iglesias, M., J. Colloid Interface Sci., 2006, 301,402–408
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O1.8 Optimized Synthesis of Gold Nanorods
Leonardo Scarabelli1,*, Marek Grzeclzak1,2, Luis M. Liz-Marzán1,2
1BioNanoPlasmonics Laboratory, CICBiomaGUNE. Paseo Miramón 182, 20009 Donostia-San Sebastían, Spain
2Ikerbasque, Basque Foundation for Science, 48011 Bilbao, Spain *[email protected]
Gold nanorods are one of the most studied metallic anisotropic nanoparticles. Their optical/electronic properties and the possibility to create assemblies both in two and three dimensions make them suitable candidates for a large number of applications, from sensing to cancer therapy or catalysis. However, the production of a library of gold nanorods with different length, thickness and size is still a challenge. This represents an obstacle for a detailed study of the size-dependence of the properties involved in the production of devices for scientific or technological applications. Recently, the use of co-factors to achieve better tunability of the synthetic protocols has been reported [1]. In this work we present how using a mild reducing agent (5-Bromo Salicylic Acid) it is possible to tune the final aspect ratio of gold nanorods over a wide range and to perform overgrowth and super-overgrowth steps to increase the size of the particles to a desired dimension. This allows us to produce a library of colloidal solutions that can be exploited for a systematic study of the properties of gold nanorods.
Acknowledgment: We would like to take this opportunity to express our sincere thanks to Plasma Quo funding from Ministerio de Economía y Competitividad de España.
[1] Ye, X. ; Jin, L.; Caglayan, H.; Chen, J.; Xing, G.; Zheng, C.; Doan-Nguyen, V.; Kang, Y.; Engheta, N.; Kagan, C.; Murray, C. B. ACS Nano, 2012, 6, 2804–2817.
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O1.9 Shearing as a driven Force to direct the Assembly of Nanocomposites Films
B. Martín-García*, M. M. Velázquez
Dpto. Química-Física, Universidad de Salamanca, Plaza de los Caídos s/n, 37008 Salamanca, Spain *[email protected]
From a technologically point of view, the fabrication of thin films of quantum dots (QDs)/polymer nanocomposites is an important issue for the development of solar cells, LEDs and sensors. Focusing the attention on the Langmuir-Blodgett technique, the monolayers prepared by compression usually lead to metastable states and space-filling defects. A way to avoid these states and promote the formation of more ordered and homogeneous films is the application of successive compression-expansion cycles [1]. Besides, to ensure a good processability and reliability of the mixed QD/polymer films, it is important the study of their dynamic properties. The Langmuir trough has been proposed as a good platform to carry out the study of the dynamics of thin films. In this field, there is little work with nanoparticle monolayers [1-3] and to best of our knowledge for mixed systems only studies realized with surfactants and nanoparticles exist [4]. In the case of nanoparticle/polymer systems theoretical studies are only available [5,6]. Therefore, we study the influence of the shearing on the mixed QD/polymer film morphology and dynamic processes involved in the reorganization following a previous work [7] focused on the characterization of Langmuir and LB films of these systems.
Brewster angle microscopy allows us to observe in situ the movements and association processes in the monolayer promoted by shearing [8]. The compression step induces compact domains while the expansion step generates cracks that propagate in the perpendicular direction to the applied stress. To analyze the effect of compression cycles on the film morphology we transfer by LB technique the monolayers after shearing. AFM and TEM images showed that the LB film becomes more close-packed, being the effect more marked at high strains, and that the QDs affect the interactions between polymer molecules and consequently, the polymer LB film morphology [6]. Finally, the analysis of the monolayer dynamics after shearing, highlighted two relaxation processes for QDs and mixed QD/polymer films: the fastest one was ascribed to rafts motions, and the slowest, related to movements inside rafts. The time-scales of these processes depend on the film composition, thus the slower relaxations correspond to systems with high polymer mole fraction probably due to impediments on the polymer matrix. Acknowledgements: The authors thank financial support from ERDF and MEC (MAT 2010-19727). B.M.G. thanks European Social Fund and Junta de Castilla y León for the FPI grant. The authors want to thank especially to Dr. J.A. Pérez-Hernández and C.L.P.U. for the AFM measurements and Electron Microscopy Service (University of Salamanca) for TEM facility.
[1] Kim, J. Y.; Raja, S.; Stellacci, F. Small 2011, 7, 2526-2532. [2] Cicuta, P.; Vella, D. Phys. Rev. Lett. 2009, 102, 138302. [3] Zang, D.; Langevin, D.; Binks, B. P.; Wei, B. Phys. Rev. E 2010, 81, 011604. [4] Guzmán, E. et al. J. Phys. Chem. C 2011, 115, 21715-21722. [5] Toepperwein, G. N.; Riggleman, R. A.; de Pablo, J. J. Macromolecules 2012, 45, 543-554. [6] Ghanbari, A. et al. Macromolecules 2012, 45, 572-584. [7] Martín-García, B.; Velázquez, M. M. Mat. Chem. Phys. Submitted. [8] Hilles, H.; Monroy, F.; Bonales, L. J.; Ortega, F.; Rubio, R. G. Adv. Colloid Interface Sci. 2006, 122, 67-
77.
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O1.10 Dissolution of ZnO nanoparticles in aqueous media:
A first essential step in nanotoxicological studies C. Rey-Castro1,*, C. David1, S. Cruz-González1, J. Salvador1, F. Mas2, J. Puy1 and J. Galceran1
1 Departament de Química and AGROTECNIO. Universitat de Lleida (Spain) 2 Departament de Química Física and IQTCUB. Universitat de Barcelona (Spain)
Dissolution of inorganic nanoparticles is one of the most relevant processes in the study of the environmental and toxicological impact of these materials. In first place, it determines their persistence in natural waters. Secondly, dissolution leads to the release of metal ions that may be potentially harmful for living organisms. Indeed, the relative importance of dissolved ions and particles on the overall toxic effect is still under debate. In this work, we present a review of the main physicochemical factors that affect the kinetics of dissolution and equilibrium solubility of ZnO nanoparticles [1], i.e.: pH, particle size and concentration, temperature, aggregation/ agglomeration, interaction with dissolved ligands and natural organic colloids (humic acids). The release of Zn2+ ions was probed by the new electroanalytical technique AGNES (Absence of Gradients and Nernstian Equilibrium Stripping) [2], which does not require a solid-liquid separation step (as opposed to conventional solubility methods). The concentration of labile Zn species in solution was also analyzed by the dynamic speciation technique DGT (Diffusive Gradients in Thin Films) [3], and the results were compared with elemental analysis of centrifuged fractions by ICP-OES. The stability, agglomeration state and particle size distributions of the samples were characterized by UV-vis spectroscopy, Laser Doppler Electrophoresis, Dynamic Light Scattering, and plunge-freeze Transmission Electron Microscopy. Figure caption: Equilibrium free Zn2+ concentration in buffered dispersions of ZnO at 0.1M ionic strength and 298K,
determined by AGNES.
Acknowledgements: The research leading to these results has received funding from the European Union 7th Framework Programme (FP7/2007-2013) under grant agreements n° 229244 (ENNSATOX) and nº 310584 (NANoREG), from Spanish Ministry of Education and Science (Projects CTQ2009-07831 and CTM2012-39183), and from Generalitat de Catalunya” (2009SGR00465). R. Wallace and N. Hondow (Institute for Materials Research, U. of Leeds, UK) carried out the plunge-freeze TEM analysis.
[1] David, C. ; Galceran, J.; Rey-Castro, C.; Puy, J.; Companys, E.; Salvador, J.; Monné, J.; Wallace, R.; Vakourov, A. J. Phys. Chem. C, 2012, 116, 11758.
[2] Companys, E.; Puy, J.; Galceran, J. Environ. Chem., 2007. 4, 347. [3] Mongin, S.; Uribe, R.; Rey-Castro, C.; Cecília, J.; Galceran, J.; Puy, J. Environ. Sci. Technol. 2013 in press
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O1.11 pH Responsive Nanoparticles for Intracellular Release of Doxorubicin
Shahla Bagherifam1,2,3,*, Vasif Hasirci1, Bo Nyström2, Gareth W. Griffiths3, Gunhild M. Mælandsmo4, Nesrin Hasirci1
1 BIOMATEN-Center of Excellence in Biomaterials and Tissue Engineering, Ankara 06800, Turkey 2Department of Chemistry, University of Oslo, Oslo, Norway.
3 Institute of Molecular Biosciences University of Oslo, University of Oslo, Oslo, Norway 4 Institute for Cancer Research, Oslo University Hospital, University of Oslo, Oslo, Norway
Chemotherapy is a common aspect of cancer treatment, which is usually applied by using mostly cytotoxic anti-cancer agents [1]. Non selectivity of chemotherapeutic agents causes to kill cancerous cells as well as normal cells, especially cells in tissues such as hair, skin, and blood cells that are replaced fast. In the last decades, various nano-sized delivery systems have been developed to be applied in cancer treatment. The newest approach is design of smart and nano-size formulations to target anti-cancer agent to a specific part of the body. This presentation concerns the use of polysebacic anhydride for anti-cancer agent delivery. For this purpose, polysebacic anhydride was first synthesized and then used to prepare nanocapsules (NC) loaded with the anti-cancer drug doxorubicin (DOX). To promote an intracellular release and to obtain pH responsibility, the prepared nanocapsules were coated by poly L-histidine (PLH). The size and morphology of both coated and non coated nanocapsules were analyzed by scanning electron microscopy (SEM) and dynamic light scattering (DLS). The antitumor activity, intracellular release and cell uptaking of formulated nanocapsules were examined on MDA-MB-231 human breast cancer cells. Figure 1 shows that free DOX primarily enters into MDA-MB-231cells and it easily localizes in the nuclei as it has been demonstrated previously [2]. For cells treated with PLH coated NCs, a significant increase of intracellular release of DOX was observed (Figure - c).
Figure caption: Confocal microscopy images for intracellular release of DOX; a) non-treated cells b) cells treated by free DOX c) cells treated by pH responsive NCs
[1] Bonetti A, et al., A phase I-II study. Tumor 2006; 92, 389-95 [2] Zhang C et al., Biomaterials 2012; 33, 2187-96
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O1.12 Solid trivalent metal dodecyl sulfates: from aqueous solution to lamellar Rui F.P. Pereira1,*, Artur J.M. Valente1, Ricardo A.E. Castro2, Hugh D. Burrows1 and
V. de Zea Bermudez2 1Dept. of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal.
2Faculty of Pharmacy, University of Coimbra, 3004-295 Coimbra, Portugal 3Dept. of Chemistry and CQ-VR, University of Trás-os-Montes e Alto Douro, 5001-801 Vila Real,
Portugal. *[email protected]
Colloidal systems involving long chain anionic amphiphiles and trivalent metal ions form ordered nanostructures through self-assembly. These systems have considerable potential in materials science, including tunable UV/visible light emitters, templated synthesis of mesoporous materials, production of lanthanide-based glasses for photonic applications, preparation of nanoparticles, and formation of metal–organic frameworks (MOFs) and layered lamellar solids. The ability to predict and tune the structure and ordering of self-assembled nanostructures leads to the development of a wide range of useful materials with enhanced physical properties.[1]
The addition of trivalent metal salts to sodium dodecyl sulfate (SDS) in aqueous solutions almost invariably leads to precipitation, due to formation of the trivalent metal dodecyl sulfates.[2,3] Metal dodecyl sulfates of trivalent aluminium, chromium, lanthanum and gadolinium were prepared by addition of the corresponding salts to aqueous solutions of SDS at the natural pH (ca.6). XRD, FT-IR and NMR spectroscopy, DSC, TGA and polarizing light thermomicroscopy demonstrate that metal dodecyl sulfates are formed with lamellar structures. These have different degrees of hydration, which depend upon the metal ion. In some cases there is evidence for coexistence of different lamellar phases. The metal is strongly bound electrostatically to the sulfate group, and although the alkyl chain is in an extended conformation, there are suggestions of local disordering of the methylene groups adjacent to the anionic head group. Studies by SEM and AFM provide evidence of periodicity, which is likely to be induced by the lamellar, layered structures. Differences are observed in the thermal behavior, which appear to reflect both the coordination behavior of the metal ion and the degree of hydration.
Figure caption: Surfactant-metal ion superstructures. [3]
Acknowledgements: MEC, FEDER, FCT and COMPETE are thanked for financial support through the projects MAT2008-06079/MAT and Pest-C/CTM/LA0011/2011. R.F.P.P. thanks FCT for a Ph.D. grant (SFRH/BD/38696/2007).
[1] Xia, F.; Jiang, L., Adv. Mater. 2008, 20, 2842–2858. [2] Pereira, R. F. P.; Tapia, M. J.; Valente, A. J. M.; Burrows, Langmuir 2012, 28, 168-177. [3] Pereira, R. F. P.; Valente, A. J. M.; Burrows, H. D.; de Zea Bermudez, V.; Carvalho, R. A.; Castro,
R. A. E., RSC Advances 2013, 3, 1420-1433.
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O1.13 Protein-nanoparticle bionconjugates: Enhanced protein stability and inhibition
of fibrillogenesis S. Goy1, A. Topete1, A. Cambón1, E. Villar-Alvarez1, N. González1, M. Alatorre-Meda1,
E. Casals2, V. F. Puntes2, S. Barbosa1,*, P. Taboada1, V. Mosquera1
1Grupo de Física de Coloides y Polímeros, Facultad de Física, Universidad de Santiago de Compostela, 15782, Santiago de Compostela, Spain
2Institut Catalá de Nanotecnología, Campus UAB, 08913 Bellaterra-Barcelona, Spain *[email protected]
Gold nanoparticles (Au NPs) from 5 to 100 nm in size synthesized with HAuCl4 and sodium citrate were complexed with the plasma protein human serum albumin (HSA). Size, surface charge, and surface plasmon bands of the Au NPs are largely modified by the formation of a protein corona via electrostatic interactions and hydrogen bonding as revealed by thermodynamic data. Negative values of the entropy of binding suggested a restriction in the biomolecule mobility upon adsorption. The structure of the adsorbed protein molecules is slightly affected by the interaction with the metal surface, but this effect is enhanced as the NP curvature decreases. Also, it is observed that the protein molecules adsorbed onto the NP surface are more resistant to complete thermal denaturation than free protein ones as deduced from the increases in the melting temperature of the adsorbed protein. Differences in the conformations of the adsorbed protein molecules onto small (<40 nm) and large NPs were observed on the basis of �-potential data and FTIR spectroscopy, also suggesting a better resistance of adsorbed protein molecules to thermal denaturing conditions. We think this enhanced protein stability is responsible for a reduced formation of HSA amyloid-like fibrils in the presence of small Au NPs under HSA fibrillation conditions.
Figure caption: Scheme showing the stabilizing effect of Au NPs on HSA fibrillation
NANOPARTICLES: ORGANIC, INORGANIC AND HYBRIDS 82
O1.14 Enzymatic Modulation in the Growth of Gold Nanorods: Ultrasensitive
detection of acetylcholinesterase inhibitors Marc Coronado-Puchau1,*, Laura Saa1, MarekGrzelczak1,2, Valery Pavlov1, Luis Liz-Marzán1,2
1CICbiomaGUNE, Paseo de Miramón 182, Donostia – San Sebastián.Spain 2Ikerbasque, Basque Foundation for Science, 48011 Bilbao, Spain
Gold nanorods have become one of the most interesting nanostructures for biosensing and imaging applications due to their unique tunable optical properties. In this study we describe a simple enzymatic assay based on the modulation of the seeded growth of gold nanorods [1], which can be used for the detection of trace amounts of acetylcholinesterase inhibitors. Acetylcholinesterase is a hydrolytic enzyme that is able to decompose acetylthiocholine to generate the thiol-bearing molecule thiocholine [2]. Since it is well known that thiols can covalently bind to gold nanoparticles (NPs), one expects that the so-formed thiocholine molecules inhibit further NP growth. Therefore, gold nanorod seeds were first pre-incubated with different concentrations of enzymatically produced thiocholine and then such seeds were added to the growth solution of gold nanorods. It was found that the resulting longitudinal surface plasmon resonance (LSPR) band of gold nanorods is sensitive to the concentration of thiocholine and a progressive change in the intensity and position of this band was observed. TEM images of the resulting NPs suggested that the modulation of LSPR position is due to the existence of 3 different NP shapes (rods, cubes and spheres), resulting in a different optical response depending on the percentage of each shape of NPs. Hence, different enzyme concentrations can be correlated with different plasmon bands and/or gold NP shapes. Finally, this assay was also used for the detection of subnanomolar concentrations of diethyl 4-nitrophenyl phosphate (paraoxon), a typical acetylcholinesterase inhibitor. In view of these findings, we propose to use this system as a simple colorimetric assay for the ultrasensitive detection of acetylcholinesterase inhibitors.
Figure caption: Scheme showing the effect of enzymatically produced thiocholine on the shape of gold NPs.
[1] Pérez-Juste, J.; Pastoriza-Santos, I.; Liz-Marzán, L. M.; Mulvaney, P. Coord. Chem. Rev., 2005, 249, 1870-1901.
[2] A.Virel; L; Saa; V. Pavlov, Anal. Chem., 2009, 81, 268–272.
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O1.15 Nanoparticles and nanodroplets as templates for inorganic synthesis:
Crystallization at surfaces and interfaces Rafael Muñoz-Espí*, Viktor Fischer, Hasan Samet Varol, and Katharina Landfester
Max Planck Institute for Polymer Research, Ackermannweg 10, 55118 Mainz, Germany *[email protected]
Colloidal systems have a great potential as supports and templates for the formation of inorganic and organic–inorganic hybrid nanostructures [1]. On one hand, colloidal particles (both polymeric and inorganic) can act as a support for crystallization processes on their surface. On the other hand, the colloidal structures generated by micelles and surfactant-stabilized droplets serve as soft templates or nanoreactors for the controlled precipitation of inorganic materials. Here, we will focus on the versatility of miniemulsions for these two strategies.
We have shown that inorganic/polymer hybrids can be prepared by in-situ formation of metal oxide (CeO2, Fe2O3, Fe3O4, ZnO) nanocrystals on the surface of polystyrene particles functionalized with hydrophilic groups [2]. The polymer particles are synthesized by miniemulsion copolymerization. The inorganic crystallization is achieved by adding a precipitating agent to a suspension of the polymer particles loaded with a metal precursor. The approach can be carried out in both aqueous and alcoholic media, which implies that it can be extended to a wide range of inorganic materials, including different chalcogenides. In this sense, we have also succeeded on preparing a “second generation” of multifunctional particles containing a magnetoresponsive inorganic component (Fe3O4) on the core and a light-responsive functionality (CdS) on the surface [3].
In addition to liquid–solid interfaces provided by polymer colloids in suspension, miniemulsions can also offer liquid–liquid interfaces that can be used to form inorganic hollow particles by soft templating. We reported before that sol–gel processes can be driven to the interface of miniemulsion droplets to form amorphous capsules of hydrous zirconia and hafnia [4]. Now, we present that interfacial crystallization can directly occur under mild conditions (even at room temperature) for different transition metal oxides and hydroxides.
[1] Muñoz-Espí, R.; Mastai. Y; Gross, S.; Landfester, K. CrystEngComm 2013, 15, 2175–2191. [2] Fischer, V.; Lieberwirth, I.; Jakob, G.; Landfester, K.; Muñoz-Espí, R. Adv. Funct. Mater. 2013, 23,
451–466. [3] Fischer, V.; Bannwarth, M. B.; Jakob, G.; Landfester, K.; Muñoz-Espí, R. J. Phys. Chem. C 2013,
117, 5999–6005. [4] Hajir, M.; Dolcet, P.; Fischer, V.; Holzinger, J.; Landfester, K.; Muñoz-Espí, R. J. Mater. Chem.
2012, 22, 5622–5628
POLYMERS, POLYELECTROLYTES, SURFACTANTS AND GELS 84
O2.1 Non-equilibrium Kinetics in Block Copolymer Micelles Observed by millisecond
Time-Resolved SAXS and SANS Reidar Lund1,*
1Dept. of Chemistry, University of Oslo Postboks 1033 Blindern, 0315 Oslo,Norway. *[email protected]
The kinetics of block copolymer micelle is still not fully understood [1]. Such processes include both equilibrium kinetics, e.g. molecular exchange, and non-equilibrium kinetics associated with morphological transitions and the formation of micelles. Earlier we have focussed on the formation kinetics where we showed that the kinetic pathway is characterised by a nucleation & growth type mechanism where unimer (single) chain is the dominating fundamental step [2]. Here we focus on the structural and kinetic aspects of a cylinder-to-sphere structural transition occurring in a model amphiphilic block copolymer system upon variation of the interfacial tension. We demonstrate that the transition is governed by entropic chain stretching in the core, which is more prominent at high interfacial tensions. We further show that we can directly follow these transitions in the real time by small angle scattering using both neutrons (TR-SANS, D11, ILL) and by x-rays (TR-SAXS, ID02, ESRF) by applying a stopped-flow apparatus for rapid mixing. The results show that the cylinders typically rapidly dissociates into spherical micelles within some few hundreds of milliseconds and thereafter reorganize to the final equilibrium spherical micelles within seconds. Interestingly, the transition seems to be driven by instabilities over the whole cylinder leading to fragmentation, which is followed by reorganization and growth of these entities into final spherical micelles. This contrasts earlier studies where the cylinders were suggested to decompose from the (more) unstable ends [3]. The opposite transition is not possible where the system rather ends up in a into another spherical micellar state. We will discuss this behaviour in connection with some recent results on the respective “equilibrium” exchange kinetics that can be accessed using time resolved SANS [1]. We will try to interrelate and discuss kinetic pathways in block copolymer micelles and how this insight might be used to create cost-effective nano-particles.
[1] Lund, R.; Willner, L.; Richter, D. Adv. Polym. Sci., 2013 (in press). [2] Lund, R.; Willner, L.; Monkenbusch, M.; Panine, P.; Narayanan, T.; Colmenero, J.; Richter, D.
Phys. Rev. Lett., 2009, 102, 188301. [3] Burke, S; Eisenberg, A. Langmuir, 2001, 17, 6705.
POLYMERS, POLYELECTROLYTES, SURFACTANTS AND GELS 85
O2.2 A unique colloidal “crystal-gel” structure observed in microgravity conditions
Juan Sabín1,*, Arthur E. Bailey2, Gabriel Espinosa3, Barbara J. Frisken2
1 Department of Applied Physics, University of Santiago de Compostela, Spain 2 Department of Physics, Simon Fraser University, Canada.
3 Instituto de Física y Matemáticas, Universidad Michoacana de San Nicolás de Hidalgo, México *[email protected]
Colloids serve as model systems to study a wide range of phases and phase kinetics. The addition of polymer to colloid solutions induces an attractive depletion force between the colloidal particles and leads to a rich phase diagram where coexistence of gas-crystal, gas-liquid-crystal and gas-liquid phases is possible [1]. One advantage of studying phase behavior in colloid-polymer systems is that the colloid-colloid interaction potential can be precisely tuned by changing the size and concentration of the polymer relative to those of the colloid. On the other hand, gravity effects may be minimized to mimic atomic systems. We have studied the interplay between phase separation and crystallization in a colloid-polymer mixture along one kinetic pathway in samples which exhibit three-phase equilibrium coexistence. In analogy with atomic systems, the range of the effective attractive interaction between colloids is sufficiently long to allow for a stable liquid phase. By direct imaging in microgravity on the International Space Station, we observe a unique structure, a ''crystal gel,'' that occurs when gas-liquid phase separation arrests due to crystallites within the liquid domain spanning the cell [2].
Figure caption: Image of a sample which exhibit a gas-liquid-crystal coexistence in Earth 30 hr after
homogenization.
Acknowledgements: We gratefully acknowledge contributions by astronauts Robert Thirsk and Shannon Walker, the Canadian Space Agency (CSA) and NASA BCAT-5 teams, Financial support was received from the CSA, the Spanish Government, and NSERC of Canada.
[1] Ilett, S. M.; Orrock, A.; Poon, W. C. K.; Pusey, P. N. Phys. Rev. E 1995, 51, 1344-1352. [2] Sabin, J.; Bailey, A. E.; Espinosa, G.; Frisken, B. J. Phys. Rev. Lett. 2012, 109, 195701.
POLYMERS, POLYELECTROLYTES, SURFACTANTS AND GELS 86
O2.3 pH-response and crosslinking time effect on chitosan nanofilms
Jonathan Miras1,*, Chao Liu2, Eva Blomberg2, Esben Thormann2, Eric Tyrode2, Susana Vílchez1, Jordi Esquena1, Karin Persson3, Per Claesson2
1Institute for Advanced Chemistry of Catalonia (IQAC), CSIC, and CIBER of Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Barcelona, Spain
2Surface and Corrosion Science Division, Department of Chemistry, Royal Institute of Technology (KTH), Stockholm, Sweden
3SP Chemistry, Materials and Surfaces, Stockholm, Sweden *[email protected]
Smart textile materials offer a wide range of high added-value applications, for use in different non-conventional sectors such as technical, biomedical or sportwear [1]. An innovative strategy for functional finishing of textile materials is based on the incorporation of a thin polymer film, which is made of stimuli-sensitive hydrogels [2, 3]. This kind of hydrogels shows response to external stimuli (i.e. pH, temperature, light, electric or magnetic field) allowing its application in a wide range of biomedical fields: delivery of therapeutic agents, tissue engineering, biological sensors, etc [4]. In this context, chitosan is especially interesting, since it is obtained by deacetylation of chitin, the second most abundant polysaccharide found in nature. It is a green biopolymer due to its excellent biocompatibility, biodegradability, non-toxicity, cationic character and low cost [5]. The purpose of the present study was to evaluate pH and crosslinking dependence of chitosan films, using a natural and non-toxic crosslinking agent, genipin. For this purpose, three different techniques were used for surface characterization of chitosan crosslinked films placed on flat silicon surfaces: dynamic contact angle, quartz crystal microbalance with dissipation (QCM-D) and atomic force microscopy (AFM). Contact angle determinations showed the hydrophilic behavior of these films, with values lower than 50º. The variation in contact angle was related to film swelling at acidic pH (protonation of amino groups of chitosan), and film shrinkage at basic pH (deprotonation of amino groups). Moreover, contact angle measurements allowed us to study the influence of crosslinking time, observing a reduction in swelling by increasing crosslinking time. The pH-response of chitosan nanofilms was also studied by QCM-D and AFM. The results confirmed that swelling and shrinking reduced due to long crosslinking time as pH change, indicating the formation of more rigid nanofilms. QCM-D showed a lower change in frequency and dissipation than that described by other authors [6], probably due to the high crosslinking leading to higher rigidity of these nanofilms. AFM observations showed that roughness did not vary as a function of pH, which was also attributed to the high crosslinking of these chitosan films.
[1] Textor, T.; Mahltig, B., Appl. Surf. Sci. 2010, 256, 1668-1674. [2] Jocic, D., Res. J. Text. Apparel 2008, 12, 58-65. [3] Kulkarni, A.; Tourette, A.; Warmoeskerken, M. M. C. G.; Jocic, D., Carbohydrate Polymers 2010,
82, 1306-1314. [4] Mano, J. F., Adv. Eng. Mater. 2008, 10, 515-527. [5] Rinaudo, M., Prog. Polym. Sci. 2006, 31, 603-632. [6] Lee, H. S.; Yee, M. Q.; Eckmann, Y. Y.; Hickok, N. J.; Eckmann, D. M.; Composto, R. J., J. Mater.
Chem. 2012, 22, 19605-19616.
POLYMERS, POLYELECTROLYTES, SURFACTANTS AND GELS 87
O2.4 Molecular Dynamic Simulations of Conjugated Polyelectrolytes with Surfactants
in Solvent Environments Beverly Stewart1,*, Joana Pragana1, S. M. Fonseca1, T. Costa1, A. T. Marques1,2, U. Scherf2
and H. D. Burrows1
1Departamento de Química, Universidade de Coimbra, Portugal.. 2Macromolecular Chemistry Group, Bergische Universität, D-42119 Wuppertal, Germany
The high efficiencies observed in photosynthetic light harvesting systems are based on their elegant self-assembled structures. In order to mimic these structures in synthetic systems it is required to both control and understand aggregation.
Here the use of molecular dynamic simulation is presented as a method by which to observe the behaviour of small fluorene based conjugated polyelectrolyte (CPE) structures [1]. Interest lies primarily in the study of both anionic and cationic charged polyelectrolyte species and their observed aggregation behavior as well as the significance of surfactant presence upon this aggregation. Dynamic simulations have thus far indicated that aggregation of CPEs in inhibited in the presence of non-ionic oxyethylene based surfactants [2], CmEn by way of separating the CPEs and encapsulating them in liquid crystalline surfactant phases. Here the effects of CmEn as well as polyvinyl alcohol (PVA) as a known water soluble polymer are examined as aggregation inhibitors. The importance of various inter- and intra-molecular interactions, as well as solute environments will be discussed as contributing factors in the production of well-defined aggregated structures. Experimental findings are also included to form an overall representation of the process. In the presence of PVA, an increase in fluorescence quantum yield and a blue shift in the emission maximum of PBS-PFP are observed. This behaviour is similar to that observed with oxyethylene surfactants, suggesting that the CPE is incorporated as isolated chains into CPE-PVA aggregates.
Figure caption: Encapsulation of CPE by Polyvinyl Alcohol
Acknowledgements: The authors thank Professor A.A.C.C. Pais for valuable discussions and the FCT for financial support through Postdoctoral Grants to BS, SMF and TC and a Ph.D. grant to ATM.
[1] Burrows, H. D.; Tapia, M. J.; Fonseca, S. M.; Pradhan, S.; Scherf, U.; Silva, C.L.; Pais, A. C. C.; Valente, A. J. M.; Schillén. K.; Alfredsson, V.; Carnerup. M.; Tomiši�, M.; Jamnik, A., Langmuir 2006, 25, 5545-5556.
[2] Burrows, H. D.; Fonseca, S. M.; Silva, C.L.; Pais, A. C. C.; Tapia, M. J.; Pradhan. S.; Scherf, U., Phys. Chem. Chem. Phys 2008, 10, 4420-4428.
POLYMERS, POLYELECTROLYTES, SURFACTANTS AND GELS 88
O2.5 Nanostructure of cationic surfactant-DNA complexes
Amalia Mezei1,*, Ramon Pons1, M. Carmen Morán2
1Department de Tecnologia de Tensioactius, IQAC-CSIC, Barcelona, Spain; 2Department de Fisiologia. Facultat de Farmacia, Universitat de Barcelona, Barcelona, Spain.
Nanostructured materials have opened new possibilities for application in novel sensors, biomaterials, drug delivery and delivery vehicles. In the last years increasing interest is focused on the structure of oppositely charged macromolecules and surfactants. The strong electrostatic attraction between the negative charges of DNA and the positive charge of the surfactant aggregates is forming complexes. The properties of cationic surfactants and DNA gel particles has been characterized recently [1-3]. However, the nanostructure of these complexes is still not clear. In the present communication an overview about the preparation and nanostructure of thin films based on four different cationic surfactants and DNA is proposed. Three different preparation methods were investigated, the obtained films were washed with water, dried at room temperature and analyzed by polarized light microscopy and X-ray measurements. A representative image of the textures obtained from polarized light microscopy is shown in Figure 1. The experimental results of X-ray measurements suggest a hexagonal packing in these complexes. Further insight into the structural properties of the complexes was obtained by Elemental Analysis from which the surfactant/base molar ratio was calculated. Different DNA helices to surfactant rods arrangement have been obtained in the complexes ranged to 2:1 or 3:1 depending on the surfactant structure. This research could be the basis for new drug-delivery applications of thin films.
(a) (b) (c) (d)
Figure caption: Representative optical polarized micrographs of cationic surfactant-DNA complexes:
(a) CTAB-DNA; (b) MTAB-DNA, (c) ALA-DNA and (d) LAM-DNA. The scale bar in (a) correspond to 50�m.
Acknowledgements: This work was supported by CSIC trough a JAE-DOC2010-097 contract co-financed by FSE 2007-2013. Financial support by CTQ2010-14897 from MINECO (Spain) and 2009SGR1331 from Generalitat de Catalunya is acknowledged. M.Carmen Morán acknowledges the support of the MICINN (Ramon y Cajal contract RyC 2009-04683). Imma Carrera is acknowledged for technical assistance and Jaume Calles for IQAC SAXS-WAXS Service and the Microanalysis Service from IQAC.
[1] Morán, M. C.; Miguel, M. G.; Lindman, B., Langmuir 2007, 23, 6478-6481. [2] Morán, M. C.; Miguel, M. G.; Lindman, B., Soft Matter 2010, 6, 3143-3156. [3] Morán, M. C.; Infante M. R.; Miguel, M. G.; Lindman, B., Pons R., Langmuir 2010, 26, 10606-
10613.
POLYMERS, POLYELECTROLYTES, SURFACTANTS AND GELS 89
O2.6 Micellar Shape Transition in an Imidazolium based-surfactant
Pedro Rodríguez-Dafonte1,*, María Figueira-González1, Vitor Francisco1, Luis García-Río1, Eduardo F. Marques2, and Mercedes Parajó1
1Centro Singular de Investigación en Química Biológica y Materiales Moleculares, Department of Physical Chemistry, University of Santiago de Compostela, 15782, Santiago de Compostela, Spain
2Centro de Investigac�ão em Química, Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, Rua do Campo Alegre, 687, 4169-007 Porto, Portugal
The self-aggregation behavior of an ionic liquid, the double-chained surfactant 1,3-didecyl-2-methylimidazolium chloride ([C10C10mim]Cl), in aqueous solution has been investigated with a number of different experimental techniques. Two critical micelle concentration values (cmc1 and cmc2) are obtained from these techniques. The cmc1 value corresponds to the formation of spherical micelles and cmc2 to the transition from spherical to cylindrical micelles. Finally, at an even higher concentration of ionic liquid, a third structural evolution is detected, from cylindrical micelles to bilayer aggregates.
Conductivity measurements of [C10C10mim]Cl in aqueous solutions were performed at different temperatures. The specific conductivity (�) plotted as a function of surfactant concentration show two slope changes that are assigned to two different critical micelle concentrations. The values of the fraction of surfactant counterions bound to the micelle (�) were obtained.
The structural change in the shape of the aggregates was confirmed by diffusion-ordered NMR spectroscopy (DOSY), from the self-diffusion coefficients for surfactant unimer and aggregates. Furthermore, a third evolution from cylindrical micelles to bilayer aggregates is proposed from the analysis of diffusion coefficients at high surfactant concentration (> 0.2 M).
Isothermal Titration Calorimetry (ITC), at temperatures between 278.15 K and 318.15 K, was used in order to obtain the corresponding standard thermodynamic parameters of micellization.
Figure caption: Enthalpogram of C10C10mimCl in water, T=288.15 K
[C10C10mimCl] /mM0 0.2 0.4 0.6 0.8
H (k
J/m
ol)
-10
-8
-6
-4
-2
0
2N N
NN
N
N
cmc1
Spherical�MicellesMonomers
POLYMERS, POLYELECTROLYTES, SURFACTANTS AND GELS 90
O2.7 Binding of cationic single-chain/dimeric surfactants to bovine serum albumin. Influence of the number of hydrophobic chains and the presence of aromatic
rings on protein-surfactant interactions María Luisa Moyá*, Victoria I. Martín, Alfredo Maestre and Amalia Rodríguez,
Department of Physical Chemistry, University of Seville, C/Profesor García González 1, 41012 Sevilla. *[email protected]
Proteins are important in living organisms and take part in many life processes. They can bind a wide variety of ligands such as bilirubin, fatty acids, hematin, metal ions, drugs and surfactants. Interactions of proteins with surfactants have been extensively studied because their mixtures have important applications in biosciences, foods and cosmetics, drug delivery, detergents and biotechnological processes [1]. It has been established that the developing protein–surfactant interaction may alter the original functional properties of the protein. This means that not only the solubility or the aggregation properties, but also the conformational parameters of the protein may be modified. The interaction between bovine serum albumin, BSA, and the single-chain surfactants N-benzyl-N,N-dimethyl-N-(1-dodecyl)ammonium bromide (PH12) and N-cyclohexylmethyl- N,N-dimethyl-N-(1-dodecyl)ammonium bromide (CH12) and their two dimeric counterparts N,N'-(1,3-phenylenebis(methylene))bis(N,N-dimethyl-N-(1-dodecyl)ammonium dibromide (12PH12) and N,N'-(cyclohexane-1,3-diylbis(methylene))bis(N,N-dimethyl-N-(1-dodecyl)ammonium dibromide (12CH12) have been investigated by surface tension, fluorescence, circular dichroism, zeta potential and atomic force microscopy. The results obtained permit the examination of how an increase in the number of hydrophobic chains and the substitution of a cyclohexyl ring by a phenyl ring, either in the head group of single-chain surfactants or in the spacer of dimeric surfactants, affect BSA-surfactant interactions. Comparison of fluorescence results with those obtained by zeta potential measurements shows differences in the binding sites of the surfactants with and without aromatic rings to the protein.
(a) (b)
(c)
(d)
Figure caption:-AFM topographic image of BSA-surfactant solutions, at pH=7 phosphate buffer, adsorbed on MgCl2 modified and non modified mica surface. a)Pure BSA (1 g/L); b)12CH12 0.01 M ; c)12CH12 5x10-5 M
+ BSA 1 g dm-3; d)12CH12 0.01 M+ BSA 1 g/L.
Acknowledgments. This work was financed by the DGCYT (grant CTQ2009-07478), the European Union and Consejería de Innovación, Ciencia y Empresa de la Junta de Andalucía (FQM-274 and P07-FQM-03056).
[1] Mishra, M.; Muthuprasanna, P.; Prabha, K. S.; Rani, P. S.; Babu, I. A. S.; Chandiran, I. S.; Arunachalam,
G.; Shalini, S. Int. J. PharmTech. Res. 2009, 1, 1354�1365.
SOFT COLLOIDS. SOFT NANOTECHNOLOGY. BIOINSPIRED SYSTEMS 91
O3.1 Monoolein-based liposomes for siRNA delivery
Ana C. N. Oliveira1,2, Thomas Martens3,4, Koen Raemdonck3, Andreia C. Gomes1, Kevin Braeckmans3,4, M. E. C. D. Real Oliveira2,*
1Center of Molecular and Environmental Biology, University of Minho, 4710-057 Braga, Portugal 2Center of Physics, University of Minho, 4710-057 Braga, Portugal
3Laboratory of General Biochemistry and Physical Pharmacy, Faculty of Pharmacy, Ghent University, Harelbekestraat 72, 9000 Ghent, Belgium
4 Centre for Nano- and Biophotonics, Ghent University, Harelbekestraat 72, 9000 Ghent, Belgium *[email protected]
Gene silencing by introducing small interfering RNAs (siRNAs) into cells is a promising therapeutic strategy for the treatment of various pathologies. In this study we propose monoolein (MO)-based liposomes, already validated for plasmid DNA delivery [1-3], as potential vehicles for siRNA delivery. It was previously shown that the inclusion of MO in liposome formulations results in nanoparticles with different structures depending on the DODAB:MO lipid molar fractions [4], which influences the in vitro performance of the lipidic carriers [2, 3]. In the present work, four formulations composed by dioctadecyldimethylammonium bromide (DODAB) or chloride (DODAC) and MO, at different cationic:neutral lipid molar ratios (2:1 and 1:2), were prepared and evaluated in order to assess their potential as in vitro siRNA nanocarriers. MO-based lipoplexes were found to be smaller than 150 nm and are highly positively charged, which favorably contributed to the high internalization as quantified by flow cytometry and confirmed by confocal microscopy (Figure 1). Cellular uptake experiments showed that internalization mainly happens through endocytosis, although a small fraction might internalize through direct fusion with the plasma membrane. DODAC:MO lipoplexes were more cytotoxic at higher charge ratios than their DODAB:MO counterparts, while the presence of more MO did not increase the toxicity of the formulations. The most efficient formulation in cellular transfection was DODAB:MO (2:1). This work shows the potential of using MO in siRNA delivery systems, and reinforces the importance of the selection of cationic lipids with the adequate counter ions to produce optimized particles for the intended use.
Figure caption: - Intracellular distribution of Cy5-labeled siRNA-lipoplexes after 4 h incubation with H1299 cells.
Red – siRNA-labeled lipoplexes; Green – endo/lysosomal compartments; Blue – cell nucleus.
Acknowledgements: This work was supported by FEDER through POFC – COMPETE and by national funds from FCT through the project PEst-C/BIA/UI4050/2011 (CBMA) and PEst-C/FIS/UI0607/2011 (CFUM) and also funding through projects PTDC/QUI/69795/2006 and SFRH/BD/46968/2009.
[1] Real Oliveira, M. E.C.D. et al. Use of Monoolein as a New Auxiliary Lipid in Lipofection, in International Patent WO2010/020935, W.I.P. Organization, 2010. p. 1-27.
[2] Neves Silva, J.; Oliveira, A.; Casal, M.; Gomes, A.; Coutinho, P.; Coutinho, O.; Real Oliveira, M.E.C.D., Biochim. Biophys. Acta 2011, 1808, 2440-2449.
[3] Neves Silva, J.; Oliveira, A.; Gomes, C.; Real Oliveira, M. E. C. D., Development of Dioctadecyldimethylammonium Bromide/Monoolein Liposomes for Gene Delivery. In Cell Interaction; Dr. Sivakumar Gowder (Ed.), InTech, 2012, Chapter X, pp 1-28
[4] Oliveira, I.; Neves Silva, J.; Feitosa, E.; Marques, E.; Castanheira, E.; Real Oliveira, M. E. C. D., J. Colloid Interface Sci. 2012, 374, 206-217.
SOFT COLLOIDS. SOFT NANOTECHNOLOGY. BIOINSPIRED SYSTEMS 92
O3.2 The cooperative interaction between hydrophobically modified inulin
and DDAB J. Morros1,*, M. R. Infante1, M. G. Miguel2, B. Lindman2, R. Pons1
1Institut de Química Avançada de Catalunya (IQAC-CSIC),Barcelona, Spain.. 2Departamento de Química da FCTUC, Coimbra, Portugal.
As petroleum feedstock decreases, the development of new renewable bio-based and efficient chemicals has attracted more and more interest. Recently, a natural polydisperse polysaccharide named inulin has gained considerable attention. This polysaccharide extracted from chicory roots consists mainly of ß(2-1)-fructosyl furanose units, and has unique properties due to its linear structure and its rather low molecular weight range in comparison to other polysaccharides such as cellulose and starch.
This relatively small polymer has focused special interest when several hydrophobic chains are attached on its backbone [1]. This hydrophobically modified inulin (HMI) is able to stabilize many dipersed systems such as o/w emulsions, solid dispersions or films by steric stabilization mechanisms [2]. Additionally, it possesses other important properties like surface activity comparable to those of molecular surfactants or thermo-reversible associative behaviour in aqueous solutions. Also, the hydrophobic groups grafted onto the polyfructose backbone tend to aggregate in order to limit their contact with the solvent leading to the formation of stable core-shell soft nanoparticles [3].
In the present work, we explore the interaction of these macromolecular structures with a well-known vesicle forming cationic surfactant, didodecyldimethylammonium bromide (DDAB). Initially, one could expect that HMI would stabilize vesicles by the already described steric stabilization mechanisms, but surprisingly this is not the case. Helped by characterization techniques, we have elucidated the nature of these polymer-surfactant interactions by proposing interaction models for surface tension, zero-shear viscosity and SAXS profiles. Here, we present our results with several synthesized HMIs [4] together with pristine inulin (without hydrophobic modifications) and Inutec®SP1 (commercial HMI) for comparative reasons, and we propose some possible applications for these interesting mixed micelles formed by DDAB and HMI.
Acknowledgements: This research was financially supported by a Bilateral Project (P2007PT0050), a COST project (COST-STSM-D36-05462), Mineco (CTQ2010-14897 and MAT2012-38047-C02-02) and Generalitat de Catalunya (CTQ2009-SGR1331). Technical support provided by J. Caelles and I. Carrera for SAXS measurements and Surface Tension measurements, respectively, is especially acknowledged. And thank you for the selflessly material support of Beneo BBC in this research.
[1] Stevens, C. V.; Meriggi, A; Peristeropoulou, M; et al., Biomacromolecules 2001, 2, 1256–1259. [2] Tadros, T. F.; Vandamme, A.; Levecke, B.; et al., Adv. Colloid Interface Sci. 2004, 108, 207-226. [3] Morros, J.; Infante, M. R.; Pons, R., Soft Matter 2012, 8, 11353-11362. [4] Morros, J.; Levecke, B.; Infante, M. R. Carbohydrate Polymers 2010, 82, 1168-1173.
SOFT COLLOIDS. SOFT NANOTECHNOLOGY. BIOINSPIRED SYSTEMS 93
O3.3 Polymeric nano-emulsions obtained by low-energy methods and their use for
nanoparticle templating M. Homs, G. Calderó* and C. Solans
Department of Chemical and Biomolecular Nanotechnology, Colloid and Interfacial Chemistry group, Institute of Advanced Chemistry of Catalonia (IQAC-CSIC) and Centro de Investigaciones Biomédica en
Red en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Barcelona, Spain. *[email protected]
Nano-emulsions are emulsions with droplet size in the range of 20-200 nm [1]. They are commonly prepared by high-energy methods (e.g. applying external energy input). However, they can be also obtained by low-energy methods (e.g. using the internal chemical energy of the components), which produce generally, smaller and more uniform droplets than high-energy methods [1-3]. Nano-emulsions prepared by low-energy methods can be advantageous for the preparation of polymeric nanoparticles. However, some parameters as the effect of polymer nature and its concentration as well as the use of partially water soluble solvents on nano-emulsion size and stability remain to be understood. The aim of this work was to study the effect of composition parameters on the stability and characteristics of the polymeric nano-emulsions and on the nanoparticles obtained using these nano-emulsions as templates. Polymeric oil-in-water (O/W) nano-emulsions were prepared in water/nonionic surfactant/[polymer in ethylacetate] systems by stepwise addition of water to the remaining components at 25ºC (phase inversion composition, PIC, method). Nano-emulsions with a water content of 90 wt% and different oil-surfactant (O/S) weight ratios were selected for these studies. The mean hydrodynamic radius of droplets was in the range of 10-100 nm depending on the polymer concentration and the O/S ratio. Stability studies showed that no sedimentation or creaming was produced as assessed by light transmittance/backscattering determinations. Polymeric nanoparticles prepared from nano-emulsions by the solvent evaporation method [4] revealed, as expected, mean sizes slightly lower than those of the corresponding template nano-emulsions due to the solvent evaporation. The results obtained together with the biocompatibility of the components selected make these nanoparticles of interest for biomedical applications.
Figure caption: Visual aspect of an (O/W) nano-emulsion and schematic representation of the nanodroplets
[1] Solans, C.; Izquierdo, P.; Nolla, J.; Azemar, N.; García-Celma, M. J. Curr. Opin. Colloid Interface Sci., 2005, 10, 102-110.
[2] Tadros, Th.; Izquierdo, P.; Esquena, J.; Solans, C. Adv. Colloid Interface Sci., 2004, 108-109, 303-318.
[3] Solans, C.; Solè, I. Curr. Opin. Colloid Interface Sci., 2012, 17, 246-254. [4] Calderó, G.; García-Celma, M. J.; Solans, C. J. Colloid Interface Sci., 2011, 353, 406-411.
SOFT COLLOIDS. SOFT NANOTECHNOLOGY. BIOINSPIRED SYSTEMS 94
O3.4 Stable capsules formed by liposomes coated by the layer-by-layer method
Ramón G. Rubio1,*, Marta Ruano1 and Francisco Ortega1
1Department of Physical Chemistry, Faculty of Chemistry, Complutense University, 28040-Madrid, Spain.
Nano- and microcapsules are important as delivery systems as well as microreactors. [1] It has been frequent to make the by using a particle as template, coating it with polymers, and finally dissolving the template. In the case of inorganic templates the last step implies to work under chemically aggressive conditions (e.g. use of HF for silica particles). In the case of polymer templates it cannot be ensured that all the polymer chains have diffused out of the capsule.[2] In this communications we describe a simple method to coat liposomes (neutral or charged) with polymers and/or particles using the layer-by-layer method. Figure 1 illustrates the coating procedure.
Figure caption: Scheme of the coating process of a liposome using the layer-by-layer method. PAH:
poly(diallyl dimethyl ammonium) chloride. PSS: sodium poly(styrene sulfonate).
Different pairs of polyelectrolytes (PAH, PSS, PGA, PLL) and also charged latex particles have been used for building the multilayers. Mixtures of phospholipids (DOPC, DPPC) and a cationic (DODAB) have allowed us to use both cationic liposomes (DOPC+DODAB) over a broad surface charge density range, and zwitterionic liposomes. The number of layers and the nature of the polymers determine the diffusion through the wall of the capsule, as well as its stability. Capsules with up to ten polymer layers have been produced that remained stable for months, and resisted centrifugation. The diffusion of a dye through the capsule wall has been studied. Acknowledgements: This work has been supported by MINECO under grant FIS2012-38231-C02-01, by COST Action CM1101, and by ESA under grants FASES and PASTA.
[1] Caruso, F. L, J. Amer. Chem. Soc. 1998, 120, 1 [2] Sukhorukov, G. D.; Donath, E.; Davis, S. Polym. Adv. Technol. 1998, 9, 8
SOFT COLLOIDS. SOFT NANOTECHNOLOGY. BIOINSPIRED SYSTEMS 95
O3.5 Serine-based catanionic liposomes as potential nanocarriers for molecular
delivery Sandra G. Silva, David Félix, M. Luísa C. do Vale, Eduardo F. Marques*
Centro de Investigação em Química (UP), Department of Chemistry and Biochemistry, Faculty of Science, University of Porto, Rua do Campo Alegre s/n, P-4169-007, Porto, Portugal.
The use of amino acids for the synthesis of surfactants with potential liposome-forming properties opens the route to the design of novel biofriendly liposomes that can aim at the controlled delivery of drugs, proteins and nucleic acids [1]. These liposomes can be based inter alia on single-surfactant systems, mixed surfactant/lipid systems or catanionic surfactant mixtures. In the latter case, the liposomes often possess several advantageous features, such as enhanced chemical and colloidal stability, as well as the possibility of charge control [2,3].
In recent years, we have addressed the synthesis and physicochemical characterization of a variety of ionic amino acid-based surfactants [4,5]. Herein, we report the phase behavior and microstructure of serine-based catanionic mixtures composed by single-chained cationic (C12, C16) and double-chained anionic (C8-8, C12-12) surfactants. Synthesis of the compounds has been performed according to a previously reported methodology [5]. Phase maps for the C12/C12-12 and C16/C8-8 mixtures are available, where regions of liposome formation can be identified. Characterization of aggregate morphology, zeta potential and stability as a function of the cationic/anionic surfactant mixing ratio, and total surfactant concentration, has been performed by DSC, tensiometry, video-enhanced light microscopy (VELM), dynamic light scattering, cryo-SEM and cryo-TEM. A rationalization of the structural evolution between aggregates as function of mixture composition is presented, on the basis of geometric packing and electrostatic effects.
Figure caption: A – Cryo-SEM and B – VELM micrographs of 16Ser/8-8Ser liposomes; C – Surface tension curves for the neat surfactants and two catanionic mixtures.
Acknowledgements: Thanks are due to the Portuguese Science Foundation (FCT) and FEDER-Compete for financial support through PTDC/QUI-QUI/115212/2009, REDE/1517/RMN/2005 and Pest/C-QUI/UI0081/2011. S.G.S. also acknowledges FCT for PhD grant SFRH/BD/61193/2009.
[1] Colomer, A.; Pinazo, A.; Manresa, M. A.; Vinardell, M. P.; Infante, M. R.; Pérez, L. J. Med. Chem. 2011, 54, 989-1002.
[2] Marques E. F., Surfactant Vesicles, in Encyclopedia of Surface and Colloid Science, 2nd ed., Taylor & Francis 2010, 1-19.
[3] Silva, B. F. B.; Marques, E. F.; Olsson, U., Soft Matter, 2011, 7, 225-236. [4] Brito, R. O.; Silva, S. G.; Fernandes, R. M. F.; Marques, E. F.; Rodriguez-Borges, J. E.; Vale, M. L. C., Colloids
Surf. B 2011, 86, 65-70. [5] Silva, S. G.; Rodríguez-Borges, J. E.; Marques, E. F.; do Vale, M. L. C., Tetrahedron 2009, 65, 4156.
SOFT COLLOIDS. SOFT NANOTECHNOLOGY. BIOINSPIRED SYSTEMS 96
O3.6 Soft Particles for Tunable Nanophotonics
Ana Maldonado-Valdivia1, Benjamín Sierra-Martín1, Antonio Fernández-Barbero1,* 1Group of Complex Fluids Physics and NanoLab,
University of Almería, 04120 Almería, Spain. *[email protected]
Metal nanoparticles and tailored surfaces exhibit optical properties which differ remarkably from those from bulk materials. One of them is the localized surface plasmon resonance. This phenomenon becomes apparent when an external electromagnetic field incident on a metal element (nanoparticles, nanovoids, …) induces electron cloud delocalization. Net charge difference on surfaces acts as restoring force, producing in the simplest case dipolar oscillation. Optical response is originated from the strong localized metal absorption when the frequency of the electromagnetic fields becomes resonant with the coherent electron motion. One of the most challenging problems concerning the photonics of nanoparticles and surfaces is the possibility of modulating the optical properties through external inputs. In this context, merging of metal and smart-soft-polymer technology to make hybrid systems leads to very successful results. In this talk, tunable optical surfaces based on soft-particles and soft-hybrid-particles photonic nanovoids are presented.
Acknowledgements: This work has been funded by the Spanish Ministerio de Economía y Competitividad/FEDER (project MAT2011-28385), Andalusian Government/FEDER (Project P010-FQM 06104) and EU-COST-Action CM1101.
COLLOIDS AND ENERGY 97
O4.1 A rheological study of magnetic fluids based on highly viscoelastic solvents
J. P. Segovia-Gutiérrez*, R. Hidalgo-Álvarez and J. de Vicente
Department of Applied Physics, Faculty of Sciences, University of Granada, C/ Fuentenueva s/n, 18071-Granada, Spain.
Wide range application of magnetic field-controllable (smart) materials is impeded by several limitations. Most, if not all of these limitations are currently associated with the fluids themselves, as opposed to the device design and manufacturing [1]. Undoubtedly, one of the most important challenge concerns particle sedimentation/aggregation and colloidal stability. In order to tackle this challenge and enhance the rheological properties, a large number of approaches and strategies have been followed in the past by using highly bidisperse fluids, ferrofluid-based colloids, two-phase emulsions and thixotropic physical gels [2]. A detailed experimental study is described in this work on the impact of polymer-colloid interactions in magnetorheological performance. To this end, a mixture [3] is investigated that provide a highly non-Newtonian character to the dispersing medium.
0 200 400 600 800 1000100
101
102
Viscoelastic fluid Viscoelastic fluid + CI 5 vol% Viscoelastic fluid+ CI 5 vol% + H0=259 kA/m
(Pa·
s)
Shear Rate (s-1) Figure caption: Shear viscosity as a function of the shear rate for three different situations. CI means
Carbonyl Iron and H0 represents the external magnetic field applied on the normal direction to the flow.
Acknowledgements: This work was supported by the MICINN MAT 2010-15101 project (Spain), the European Regional Develop-ment Fund (ERDF) and the Junta de Andalucía P09-FQM-4938, P10-FQM-5977, P10-RNM-6630 and P11-FQM-7074 projects (Spain). J.P. S.-G. acknowledges financial support by the ”Ministerio de Educación: Becas del Programa de Formación del Profesorado Universitario (FPU)” (AP2008-02138). J. de V. and R. H.-A. thank the financial support received from CEI-Biotic 20F12/16.
[1] Klingenberg, D. J., AIChE Journal 2001, 47, 246-249. [2] de Vicente, J.; López-López, M. T.; González-Caballero, F.; Durán J. D. G., J. Rheol. 2003, 47,
1093-1109. [3] Stokes J. R., Swirling flow of viscoelastic fluids. Research Collections (UMER), 1998.
COLLOIDS AND ENERGY 98
O4.2 Band gap engineering with subnanometric metal (0) clusters:
catalytic, electrocatalytic & photocatalytic applications M .A. López-Quintela1,*, N. Vilar-Vidal1,2, D. Buceta3, M. C. Blanco1 and J. Rivas2
1Laboratory of Magnetism and Nanotechnology (Nanomag), Technological Research Institute, University of Santiago de Compostela, E-15782 Santiago de Compostela, Spain
2INL-International Iberian Nanotechnology Laboratory. 4715-330 Braga. Portugal. 3 Chemistry Department. Brookhaven National Laboratory 11973, Upton, NY, USA.
Metal clusters formed by a small number of metal (0) atoms represent a novel state of matter, located between the classical bulk (or nanoparticle) behaviour and the different behaviour of the corresponding atoms. In the last years we have developed simple, efficient and scalable soft chemical routes for the production of metal (0) clusters of Au, Ag, Pt, and Cu, based on the use of kinetic control. Such techniques allow the production of relative monodisperse clusters, Mn, in the range � 1< n< 50 (i.e. with sizes � < 1-2nm), without using strong ligand agents, which can inhibit many of their interesting properties.
Different catalytic studies with metal clusters have shown that these tiny compounds open up new horizons and opportunities of research concerning the development of a completely new family of novel catalytic materials, able to cover a broad range of green reactions related with: 1) the substitution of oxidants by oxygen in green chemistry, including the partial and total oxidation by molecular oxygen of alcohols, olefins and thiols at room temperature and aerobic conditions, etc.; 2) the electrocatalysis in fuel cells, including hydrogen and alcohol electrooxidation, as well as the oxygen reduction reaction, and 3) the photocatalytic conversion of solar light for driving chemical reactions, with especial attention to the light driven production of hydrogen by water splitting and detection and photodecomposition of contaminants (see figure below). A summary of the most recent results in this area of catalysis with atom-level resolution, using a common framework for -until now- almost unrelated different catalysis fields, will be provided in this talk.
Figure caption: Selective Pb2+sensoring and its photocatalytic UV-elimination by Cu13 clusters (left). Self-explained energy diagram of the observed sensing and selectivity (right).
Acknowledgements: We want to acknowledge the financial support of the MCI and Xunta de Galicia, Spain (MAT2010-20442; Grupos Ref.Comp. 2010/41, respectively).
SURFACES AND INTERFACES 99
O5.1 NMR self-diffusion studies on the binding and exchange dynamics between
block copolymers and carbon nanotubes Ricardo Fernandes1,2, Michael Shtein3,, Ilan Pri Bar3, Oren Regev3, István Furó2, and
Eduardo F. Marques1,*
1Centro de Investigação em Química, Department of Chemistry and Biochemistry, Faculty of Science, University of Porto, Rua do Campo Alegre, s/n, P-4169-007 Porto, Portugal.
2Division of Applied Physical Chemistry, Department of Chemistry, KTH Royal Institute of Technology, SE-10044 Stockholm, Sweden.
3Department of Chemical Engineering and the Ilse Katz Institute for Nanotechnology, Ben-Gurion University of the Negev, 84105 Beer-Sheva, Israel
*[email protected] Carbon nanotubes (CNTs) are emerging materials with a wealth of applications in
different areas, ranging from molecular devices and sensors, to nanocomposites and drug delivery. However, pristine CNTs tend to bundle into strongly bound aggregates due to van der Waals interactions. This is a drawback, since major applications often require individually dispersed CNTs. One possibility to overcome this issue is by the use of non-covalent dispersants (surfactants, polymers or biomolecules), which are able to exfoliate and stabilize CNTs in aqueous solution. Despite active research in the field, non-covalent dispersion is still poorly understood at molecular level [1].
In what concerns polymers as dispersants, two main qualitative models on the polymer-CNT interaction are available. In one, the polymers coat the CNT in a tight contact referred to as wrapping. In the other, a loose adsorption is proposed, in which a weaker interaction between the polymer and the CNT takes place, so that the bound polymer remains almost like in its natural state in a good solvent, i.e. in a random coil.[2]
In this work, we have studied by 1H NMR diffusometry the exchange dynamics between the CNT surface and the bulk of triblock copolymers Pluronic® F127, F87 and F68 (of general structure (PEO)m(PPO)n(PEO)m, where m=65 and n=100 for F127; m=61 and n=41 for F87; m=76 and n=29 for F68) and single walled nanotubes (SWNT). A non-monoexponential 1H echo decay is observed for all polymers, that changes character upon change in the diffusion time �, which indicates a situation where the exchange time lies on the experimental time scale (). The initial fast decay corresponds to the “freely”-diffusing polymer in the bulk, while the slow decay is associated with CNT-bound polymer. Thus, for instance, the self-diffusion coefficient of F127 in CNT-adsorbed state is found to be of the order of 2.2 × 10-12 m2.s-1, ca 30-fold smaller than that obtained for the unbound polymer in water (5.9 × 10-11 m2.s-1). The possibility of lateral diffusion of the polymer coil on the CNT surface being at stake has been systematically investigated. For all polymers studied, one observes that the major polymer fraction is in the free-state, while a small fraction is adsorbed onto the nanotube, with a characteristic average residence time.[3] A correlation between the polymer residence time and the relative PEO/PPO block size will be presented. Overall, the results seem to support the “loose adsorption” model for polymer-CNT interaction. Acknowledgements: Thanks are due to the Portuguese Science Foundation (FCT) and FEDER-Compete for financial support through project PTDC/QUI-QUI/115212/2009 and Centro de Investigação em Química (CIQ-UP) through project Pest/C-QUI/UI0081/2011. RF also acknowledges FCT for the Ph.D. grant SFRH/BD/72612/2010. The Swedish Research Council VR is also kindly acknowledged. [1] Wang, H. Curr. Opin. Colloid Interface Sci. 2009, 14, 364-371. [2] Granite, M.; Radulescu, A.; Pyckhout-Hintzen, W.; Cohen, Y. Langmuir 2011, 27, 751-759. [3] Frise, A. E.; Pages, G.; Shtein, M.; Pri Bar, I.; Regev, O.; Furó, I. J. Phys. Chem. B 2012, 116, 2635-2642.
SURFACES AND INTERFACES 100
O5.2 Probing in-vitro digestion of interfacial protein structures in a single droplet Julia Maldonado-Valderrama1,*, Juan A. Holgado Terriza2, Amelia Torcello-Gómez1 and
Miguel A. Cabrerizo-Vílchez1
1Applied Physics Department. Campus de Fuentenueva sn, 18071. University of Granada, Spain. 2Department of Sofware Engineering, C/Periodista Daniel Saucedo Aranda, sn, 18071, University of Granada, Spain.
This study has been designed to investigate the effects of gastrointestinal digestion on protein covered interfaces. We have used a new device, fully designed and assembled at the University of Granada: the OCTOPUS, which provides a customised static sequential in vitro digestion process in a single droplet. The evolution of the interfacial tension throughout the whole simulated gastrointestinal transit is measured in-situ and the mechanical properties of the interfacial layer (interfacial dilatational modulus) after each digestion stage. The in-vitro digestion model used here focuses on pepsinolysis and lipolysis of two dairy proteins: -lactoglobulin (BLG) and -casein (BCS) adsorbed at the olive oil–water interface. The results show different susceptibilities of interfacial layers of BLG and BCS to pepsinolysis; while pepsinolysis of adsorbed BLG weakens the interfacial network, pepsinolysis of adsorbed BCS strengthens it as measured by the dilatational moduli. These numbers provide an interfacial scenario for previous findings on emulsification of these proteins, which was found to improve BLG pepsinolysis but somehow protected BCS from pepsinolysis in the stomach. The desorption profiles provide quantification of the extent of lipid digestion in subsequent simulated intestinal fluid containing lipase. The extent of lipid hydrolysis was found to be similar in BLG and BCS covered interfaces and comparable to that in the absence of coverage (pure oil–water interface) indicating that proteins do not comprise a barrier to lipolysis. This is attributed to the similar interfacial properties of the interfaces reaching the duodenum despite the structural differences between native BCS and BLG, thus demonstrating the impact of the transit through the gut on lipolysis. This research allows identification of the interfacial mechanisms affecting enzymatic hydrolysis of proteins and lipolysis. The results can be exploited in tailoring novel food matrices with improved functional properties such as decreased digestibility, controlled energy intake and low allergenicity.
Figure caption: Detail of the exchange procedure. Interfacial tension following in-vitro digestion of BLG adsorbed at the olive oil-water interface.
Acknowledgements: This work has been sponsored by the EU-FP7-PERG07-GA-2010-268315-ColloDi and projects JCI-2009-03823, MAT2010-20370 and MAT2011-23339 (MICINN), P08-FQM-4325 and P09-FQM-4698 (Junta de Andalucía) and CEI-Biotic 20F12/16 and Microproyecto2013(UGR).
[1] Maldonado-Valderrama, J.; Holgado-Terriza, J. A.; Torcello-Gómez, A.; Cabrerizo-Vílchez, M. A., Soft Matter, 2013, 9, 1043-1053.
SURFACES AND INTERFACES 101
O5.3 Effect of porosity and surface material in the transport of ions across
nanoporous alumina membranes V. Romero1, V. Vega2, J. García2, R. Zierold3, K. Nielsch3, V. M. Prida2, B. Hernando2,
J. Benavente1,* 1Dpto. Física Aplicada I, Facultad Ciencias, Universidad Málaga, E-29071-Málaga, Spain.
2Dpto. de Física, Facultad de Ciencias, Universidad de Oviedo, E-33007-Oviedo, Spain. 3Institut für Angewandte Physik, Jungiusstrasse 11, D-20355 Hamburg, Germany.
Nanoporous Anodic Alumina Membranes (NPAMs) synthesized via electrochemical anodization of aluminium are formed by self-ordered structures with parallel aligned and well defined pores keeping honeycomb structure geometry [1]. The excellent chemical and thermal stability of NPAMs favor their use in separation processes, mainly when heavy metal or corrosive products are involved, while their practically ideal porous structure allows them to be considered as model systems for the study of mass and ions transport [2]. Moreover, NPAMs are also employed in biosensor construction and drug-delivery applications, but problems associated to surface hydrophobicity and the lack of biocompatibility are factors of significant importance, although they might be over-passed by surface coating with adequate materials [3].
The objective of this work is to establish the effect of both inter-pore distance/porosity and surface nature in the transport of ions though NPAMs. For these reasons four nanoporous membranes were chosen: i) two NPAMs with similar pore radii (~ 10 nm) but different porosity (10 % (AL-Sf) and 37% (ANP)) and suppliers; ii) two NPAMs with similar pore radii and porosity (~ 6 nm and 3 %, respectively) but modified surfaces by ADL deposition of Al2O3 (AL-Sf/Al2O3) or SiO2 (AL-Sf/SiO2) nanoparticles coating layers. Membrane potentials measurements were performed using NaCl solutions at different concentrations (0.002 M to 0.1 M) for all the NPAMs. The differences among them give significant information on the effect of pore size, porosity and pore/membrane surface nature on ions diffusion coefficients (D+ and D-) across the nanopores and the membrane effective charge (Xef) as it can be seen in Table 1.
Table 1: Effective fixed charge (Xef), average porosity and pore radii <rp>� and ionic diffusion coefficients (D+ and D-).
membrane Al-Sf ANP Al-Sf/Al2O3 Al-Sf/SiO2 Xef (M) 20.0x10-3 0.9x10-3 24.0 x10-3 3.0x10-3
rp � nm� 11 10 6 6 (%) 10 37 3 3
D+ (m2/s) 2.1x10-10 1.0x10-9 2.0x10-10 7.2x10-10 D- (m2/s) 1.3x10-9 1.9x10-9 1.2x10-9 1.4x10-9
Acknowledgements: To CICYT (projects CTD2011-27770 (FEDER funds) and MAT2010-20798-C05-04) for financial support. V. Romero also thanks to CICYT for her FPU grant.
[1] Eftekhari, A. Nanostructured Materials in Electrochemistry, Wiley-VCH, Weinheim, 2008. [2] Romero, V.; Vega, V.; García, J.; Prida, V. M.; Hernando, B.; Benavente, J. J. Colloids Interface
Sci. 2012, 376, 40-46. [3] Losic, D.; Cole, M. A.; Dollmann, B.; Vasilev, K.; Griesser, H. J. Nanotechnology 2008, 19, 245704.
SURFACES AND INTERFACES 102
O5.4 Bulk and interfacial Microrheology
Francisco Ortega1,*, Laura J. Bonales1, Armando Maestro1 , Nuria Mancebo1, Fernando Martínez-Pedrero1, José E. Fernandez-Rubio1, Raquel Chuliá, Alma J. Mendoza1,
Ramón G. Rubio1 1Departamento de Química Física I, Universidad Complutense de Madrid, Ciudad Universitaria s/n
Madrid, Spain *[email protected]
Micro and nanoreology [1,2] encompass a family of methods that uses micro- and nanoparticles as mechanical probes of the rheological behavior of soft materials. Microrheology presents several advantages over conventional mechanical rheology: smaller size samples ( μL), use in heterogeneous samples (i.e. simultaneous measurement of several environments), use in situ (e.g. cells), high throughput screening capability and very small perturbation applied (in passive microrheology the thermal energy KBT). The fact that the applied stress is very small is of great importance when dealing with interfacial systems which are very fragile soft materials.
We will discuss the experimental techniques [1,2] and the different procedures [3] used to extract the complex shear modulus from the microrheological experiments. In this discussion we will present results from two different 3D systems, agarose gel solutions and pluronic solutions, and several monolayers (quasi-2D systems) of surfactants and polymers.
Acknowledgements: This work has been supported by MINECO under grant FIS2012-38231-C02-01, by COST Action CM1101 and by ESA under grants FASES and PASTA.
[1] Waigh, T. A. Rep. Prog. Phys. 2005, 68, 685. [2] Mason, T. G.; Weitz, D. A. Phys. Rev. Lett. 1995, 74, 1250 [3] Mason, T. G. Rheol. Acta, 2000, 39, 371.
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O5.5 Segregation of silica particles with different size using driven receding contact
lines Carmen L. Moraila-Martínez*, Miguel A. Cabrerizo-Vílchez and
Miguel A. Rodríguez-Valverde
Biocolloid and Fluid Physics Group, Department of Applied Physics, University of Granada, Campus of Fuentenueva, E-18071 Granada, Spain.
The formation of solute deposits during the evaporation of sessile drops containing complex liquids (solid particles, polymeric dispersions, emulsions) is recognized as a multivariable process. The diversity in the deposit morphology is due to the complex mechanisms behind the transport of particles during drop evaporation. It is known [1] that small particles may be readily arranged at the vicinity of contact lines rather than larger particles due to the wedge-like shape of the solid-liquid-air interfacial region (in hydrophilic substrates). Although segregation effects in coatings are undesirable in many industrial and scientific processes, the discrimination of particles with different size on a substrate can be also fruitful [2].
The obscure contact line dynamics, the competition of inwards and outwards flows within the evaporating drop and the increasing concentration of particles in bulk may hinder the actual mechanisms that lead or mitigate the ring-like deposit formation. Recently, we have developed a new methodology [3] to mimic the contact line dynamics of evaporating drops at shorter times using a nonlinear suction from the drop bulk. With this methodology, referred to as Controlled Shrinking Sessile Drop (CSSD), we are able to decouple the sustained evaporation from the contact line motion, as Bodiguel et al. reported [4]. Unlike drop evaporation, particle concentration in bulk remains constant for a CSSD experiment.
In this work, we studied the size dependent nano/microparticle separation near the contact region of driven receding contact lines without macroscopic evaporation. We probed the behavior of monomodal suspensions and binary mixtures of silica particles on a polymer substrate with the CSSD methodology. To explore the particle segregation in ring-like deposits, the electrostatic interactions (substrate-particle and particle-particle) were minimized and the substrate receding contact angle was fixed. The height and width of the ring-like deposits increased as the particle size whereas the ring diameter decreased as the particle size. With the CSSD technique, smaller particles are able to penetrate further into the edge of the drop. With these results, the application of the CSSD methodology with particle suspensions may become a simple colloidal-assembly strategy.
Acknowledgements: This work was supported by the "Ministerio Español de Ciencia e Innovación" (project MAT2011-23339) and the "Junta de Andalucía" (projects P08-FQM-4325 and P09-FQM-4698).
[1] Perelaer, J.; Smith, P. J.; Hendriks, C. E.; van den Berg, A. M. J.; Schubert, U. S. Soft Matter, 2008, 4, 1072–1078.
[2] Wong, T.-S.; Chen, T.-H.; Shen, X.; Ho, C.-M. Anal. Chem., 2011, 83, 1871–1873. [3] Moraila-Martinez, C. L.; Cabrerizo-Vilchez, M. A.; Rodriguez-Valverde, M. A. Soft Matter, 2013, 9,
1664–1673. [4] Bodiguel, H.; Doumenc, F.; Guerrier, B. Eur. Phys. J. Spec. Top., 2009,166, 29-32
SURFACES AND INTERFACES 104
O5.6 Ions-Induced Nanostructuration of Hydrophobic Polymer Surfaces
Carlos Drummond1,*, Igor Siretanu2, Delfi Bastos and Jean-Paul Chapel1
1Centre de Recherche Paul Pascal, UPR8641 CNRS. Avenue Schweitzer, 33600 Pessac Cedex, France 2Physics of Complex Fluids, MESA Institute for Nanotechnology, University of Twente, Post Office Box
217, 7500 AE Enschede, The Netherlands. 3Biocolloid and Fluid Physics Group. Department of Applied Physics, University of Granada. Av.
Fuentenueva S/N, 18071 Granada, Spain *[email protected]
When hydrophobic surfaces are in contact with water in ambient conditions a layer of reduced density is present at the interface, preventing the intimate contact between the two phases. Reducing the extent of this layer by degassing the water promote ionic adsorption on the hydrophobic. This process can induce long-lasting deformation of hydrophobic glassy polymer films, a process called ion-induced polymer nanostructuration, IPN [1]. The self-assembled structure spontaneously relaxes back to the original flat morphology after few weeks at room temperature. This instability and the self-assembled structure are controlled by the hydrophobic surface charge, which is determined by the composition of the aqueous phase, and by the amount of gas dissolved. We have found that this process is ion-specific; larger surface modification is observed in the presence of water ions, hydrophobic and amphiphilic ions. Surface structuration is also observed in the presence of certain salts of lithium [2]. This effect can be easily adjusted to modify different hydrophobic polymeric substrates at the submicrometer level, opening pathways for producing controlled patterns at the nanoscale in a single simple waterborne step [3].
Figure caption: 1μmx1μm height tapping mode AFM micrographs taken in air of 300 nm thick 250 kDa polystyrene films as prepared (spin-coated) (a); after exposure to a non degassed (b) and degassed (c) solution of nitric acid in double distilled water at pH 1.5 and room temperature. A typical height profile for each condition is presented. The presence of asperities of regular nanometric size is clearly observed on the surface exposed to the degassed solution for 5 minutes. On the contrary, no modification was detected when an identical film was exposed to the same solution under identical conditions before removing the dissolved gases.
[1] Siretanu, I.; Chapel, J. P.; Drummond, C. ACSNano 2011, 5, 2939-47 [2] Siretanu, I.; Chapel, J. P.; Bastos-González, D.; Drummond, C. JPCB (Submitted) [3] Siretanu, I.; Chapel, J. P.; Drummond, C. Macromolecules 2012, 45, 1001-05
SURFACES AND INTERFACES 105
O5.7 Quantum Dots onto Polymer and Surfactant self-assembled Films:
A Quartz Crystal Microbalance Study T. Alejo*, M. D. Merchán and M. M. Velázquez
Departamento de Química Física, Facultad de Ciencias Químicas, Universidad de Salamanca. 37008 Salamanca, Spain.
The study of the adsorption of nanomaterials onto surfaces has attracted extensive interest considering the importance of the interactions of nanoparticles with polymeric or biological templates. Thin polymer and surfactant films are used for applications as microelectronic devices, solar cells, sensors, biomaterials or as adhesives, lubrication and membranes. For nanocomposite material applications it is necessary to control the incorporation of nanoparticles into the polymer films, the surface chemistry, spatial patterning and physical properties. Quantum dots (QDs) nanocrystals are particularly interesting for its applications in bioanalytics and optoelectronics [1]. Thus, in previous work we have studied the properties of Langmuir and Langmuir-Blodgett monolayers prepared with the polymer PMAO and Gemini surfactant 18-2-18 and QDs [2-3]. In this sense, Quartz Crystal Microbalance with Dissipation monitoring (QCM-D) technique allow us to investigate the kinetic self-assembly process of the molecules in an attempt to gain insight into the role of the interaction between the organic molecules and nanoparticles. Moreover, it allows us to measure the mass of the films adsorbed and its mechanical properties.
Firstly, the polymer and surfactant adsorption onto the SiO2 crystal sensor was analyzed, showing a different amount of material adsorbed at the end of the process for the polymer, the surfactant and their mixtures. Moreover, the dissipation factor (�D) pointed to an energetic adsorption in the polymer with shorter times. Meanwhile, in the surfactant and polymer/surfactant mixtures the adsorption process showed a higher entropic contribution. The dissipation factor values indicate than the polymer present a planar conformation of their molecules at the interface while the surfactant and surfactant-PMAO mixtures give a higher packing of molecules with their hydrocarbon chains oriented perpendicularly to the interface. The analysis of the adsorption kinetics curves agrees with a bimodal adsorption process, in which the first characteristic time is ascribed to a fast adsorption process of the molecules to the surface of the sensor, meanwhile the second time corresponds to a reorganization process of the molecules, corresponding to the slowest process with times of thousand of seconds. From our results it is possible to conclude that the PMAO and Gemini surfactant increase the QDs coverage compared with QDs films where the nanoparticles are directly adsorbed onto the SiO2 sensor, leading to a greater coverage when the nanoparticles are adsorbed onto polymer/surfactant mixtures. Acknowledgements: The authors thank financial support from ERDF and MEC (MAT 2010/19727). T.A. wishes to thank European Social Fund and Junta de Castilla y León for the FPI grant. The authors want to thank especially to Drs J.A. Pérez-Hernández for the AFM measurements and C.L.P.U. (University of Salamanca) for the AFM facility.
[1] Somers, R. C.; Bawendi, M. G.; Nocera, D. G. Chem. Soc. Rev., 2007, 36, 579-591. [2] Alejo, T.; Merchán, M. D.; Velázquez, M. M.; Pérez-Hernández, J. A. Mater. Chem. Phys., 2012, 138, 286-
294. [3] Alejo, T.; Merchán, M. D.; Velázquez, M. M. Thin Solid Films, 2011, 519, 5689-5695.
SURFACES AND INTERFACES 106
O5.8 Sudden Field Induced Sublimation In 2D Colloidal Crystallites
F. Martínez-Pedrero1,2,*, J. E. Fernandez- Rubio2, R. G. Rubio2 and F. Ortega2
1CEI Campus Moncloa, UCM-UPM, Madrid, Spain. 2Universidad Complutense, Facultad de Química, Departamento de Química Física I,
Ciudad Universitaria, Madrid, Spain. *[email protected]
Colloidal particles absorbed at liquid interfaces are of interest in condensed-matter physics in relation to a wide range of phenomena, including mechanism of ordering and self-assembly, vitrification, melt or sublimation processes in two dimensions (2D) [1]. In the sublimation processes crystallites of finite size melt into a liquid or sublimate into a gas at a steady rate from the perimeter, while the interior retains its crystalline order. Only below a characteristic size, a metastable disordered phase seems to appear causing the rapid vaporization of the system [2]. Here, we study the kinetics of sublimation in 2D crystallites that occurs when dipolar repulsion is suddenly implemented between the constituent particles. Contrary to these usual thermal processes, we found that in the field induced sublimation the particles melt simultaneously through the entire crystal, at least for relatively high dipolar interactions and tiny crystallites. A scaling behavior suggests a universal sublimation mechanism for these small planar crystals in processes induced by strong enough repulsive interactions. A second mechanism does not yet understood appears above a characteristic size, which depends on the implemented repulsion between the particles. Figure caption: Paramagnetic polystyrene colloidal beads of average diameter 3.9 �m confined to the water/air interface at 22°C. In the absence of the magnetic field the particles reversibly aggregate through van der Waals and attractive capillary forces, forming ordered clusters through the field of view. By implementing a strong enough magnetic repulsion, as compared with the attractive interactions between the particles, a complete phase transition occurs and the mono-crystals rapidly go from an ordered to a disordered state.
Acknowledgements: This work has been supported by MINECO under grant FIS2012-38231-C02-01, by COST Action CM1101 and by ESA under grants FASES and PASTA. Research by F.M.P. has been supported by a PICATA fellowship from the Moncloa Campus of International Excellence (UCM-UPM).
[1] Bonales, L. J.; Martínez-Pedrero, F.; Rubio, M. A.; Rubio, R. G.; Ortega F., Langmuir 2012, 28, 16555-16566.
[2] Savage, J. R.; Blair D. W.; Levine A. J.; Guyer R. A.; Dinsmore A. D., Science 2006, 314, 795-798.
MODELING AND SIMULATIONS 107
O6.1 Stochastic diffusion of isotropic and liquid crystal phases of rodlike colloidal
particles: Monte Carlo and Brownian Dynamics meet Alessandro Patti1,* and Alejandro Cuetos2
1Institute of Advanced Chemistry of Catalonia (IQAC-CSIC) and CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Jordi Girona 18-26 - 08034 Barcelona, Spain.
2Department of Physical, Chemical and Natural Systems, Universidad Pablo Olavide, 41013 Sevilla, Spain.
Motivated by the growing interest on applying stochastic algorithms to investigate the dynamics of equilibrium [1] and out-of-equilibrium [2] colloidal fluids, and by recent attempts to mimic the Brownian Dynamics (BD) with Monte Carlo (MC) simulations [3,4], we study the diffusion of merely repulsive and freely rotating colloidal rods in the isotropic, nematic and smectic liquid crystal phases, to probe the agreement between Brownian and MC dynamics under the most general conditions. By properly rescaling the MC time step, being related to any elementary move via the corresponding self-diffusion coefficient, with the acceptance rate of simultaneous trial displacements and rotations, we demonstrate the existence of a unique Monte Carlo time scale that allows for a direct comparison between MC and BD simulations. To estimate the validity of our theoretical approach, we compare the mean square displacement of rods, their orientational autocorrelation function, and the self-intermediate scattering function, as obtained from Brownian dynamics and MC simulations. The agreement between the results of these two approaches, even under the condition of heterogeneous dynamics generally observed in liquid crystalline phases, is excellent [5].
Acknowledgements: A. P. acknowledges a Juan de la Cierva Grant No. JCI-2010-06943 from the Spanish Ministry of Science and Innovation (MICINN) and a Beatriu de Pinós Grant No. 2009-BP-B00058 from AGAUR. A. C. acknowledges funding from the Operative Programme FEDER-Andalucía 2007–2013 through Project No. P09-FQM-4938 and from MICINN through Project No. MAT2011-29464.
[1] Patti, A.; El Masri, D.; van Roij, R.; Dijkstra, M. Phys. Rev. Lett., 2009, 103, 248304. [2] Berthier, L.; Kob, W. J. Phys.: Condens. Matter, 2007, 19, 205130. [3] Sanz, E.; Marenduzzo, D. J. Chem. Phys., 2010, 132, 194102. [4] Romano, F.; De Michele, C.; Marenduzzo, D.; Sanz, E. J. Chem. Phys., 2011, 135, 124106. [5] Patti, A.; Cuetos, A. Phys. Rev. E. 2012, 86, 011403.
MODELING AND SIMULATIONS 108
O6.2 Coarse-grained Monte Carlo simulations of thermo-responsive polyelectrolyte
nanogels Manuel Quesada-Pérez1,*, José. A. Maroto-Centeno1 and Alberto Martín-Molina2
1University of Jaén, Department of Physics (Spain). 2University of Granada, Department of Applied Physics (Spain).
The classical formalism of gel swelling is not useful for networks of a few nanometers when they are considered from a colloidal perspective because it is not possible to consider the electric double layer around the polyelectrolyte network. In spite of this limitation, coarse-grained simulations had not been applied to temperature-sensitive polyelectrolyte nanogels yet, as far as we know. In this work, we have simulated thermo-responsive nanogels within the bead-spring model of polyelectrolyte and a solvent-mediated hydrophobic interaction potential that captures the swelling behavior of real microgels[1]. Regarding the thermal response, our results qualitatively agree with those previously published for macroscopic gels[2]. Charge profiles reveal that shrunken charged nanogels form a hollow sphere, with the charged monomeric units concentrated on the inner and outer surfaces, and some counterions accumulated in the inner space (see figure). Thus they really behave as closed containers. Additionally, simulations show that the surface electrostatic potential increases when temperature-sensitive nanogels shrink upon heating.
Counterion profiles were also calculated from a very simple Poisson-Boltzmann (PB) cell model. Its predictions about the charge profile outside the nanogel, the fraction of counterions inside and the surface electrostatic potential are in fair agreement with simulation data. Thus, the PB cell model can provide useful information about the electric double layer of thermo-responsive micro- and nanogels.
Figure caption: Cross section of a snapshot of a collapsed nanogel.
Acknowledgements: i) ‘Ministerio de Ciencia e Innovación, Plan Nacional de Investigación, Desarrollo e Innovación Tecnológica (I+D+i)’, Projects MAT2012-36270-C04-04 and -02. ii) ‘Consejería de Innovación, Ciencia y Empresa de la Junta de Andalucía’, Project P09-FQM-4698.
[1] Quesada-Pérez, M.; Ramos, J.; Forcada, J.; Martín-Molina, A.; J. Chem. Phys. 2012, 136, 244903. [2] Quesada-Pérez, M.; Maroto-Centeno, J.A.; Martín-Molina, A.; Macromolecules 2012, 45, 8872.
MODELING AND SIMULATIONS 109
O6.3 Effective electrostatic interactions arising in core-shell charged microgel
suspensions with added A. Moncho-Jordá1,*, J. A. Anta2 and J. Callejas-Fernández1
1Biocolloid and Fluid Physics Research Group, Departamento de Física Aplicada, Facultad de Ciencias, Universidad de Granada, Campus Fuentenueva S/N, 18071 Granada, Spain.
2Departamento de Sistemas Físicos, Químicos y Naturales, Universidad Pablo de Olavide, Carretera de Utrera, Km 1, 41013. Sevilla, Spain.
The mixture formed by charged (ionic) microgels in the presence of 1:1 added salt, with explicit consideration of a core-shell structure of the microgel particles, is studied [1]. By solving numerically the three-component Ornstein-Zernike integral equations, the counter- and coion penetration inside the microgel network and the resulting effective microgel-microgel electrostatic interaction are calculated. This is done in the limit of very low microgel concentration, so that the resulting pair-wise effective potential is not affected by many-body particle-particle interactions. The ion-ion, microgel-ion and microgel-microgel correlations are all treated within the Hypernetted-Chain (HNC) approximation. The results obtained clearly show that the addition of salt to the microgel suspension has a deep impact on the screening of the bare charge of the particles, confirming an already well-known result: the strong reduction of the effective charge of the microgel occurring even for diluted electrolyte concentrations [2]. We show that this effect becomes more important as we increase the shell size of the particle, and derive a semi-empirical model for the effective charge as a function of the electrolyte concentration and the shell extension. The resulting microgel-microgel effective pair potential is analysed as a function of the shell extension and salt concentration. In all cases the interaction is a soft potential when particles overlap. For non-overlapping distances, our theoretical results indicate that microgel particles can be regarded as hard spherical colloids bearing an effective charge given by the net charge inside the particle, and the microgel-microgel interaction shows a Yukawa-like behaviour as a function of the interparticle distance. It is also observed that increasing the bare-charge of the microgel induces a strong microgel-counterion coupling in the limit of very low electrolyte concentrations, which can not be justified using linearized theories. This leads to a even more important adsorption of counterions inside the microgel network, and to a reduction of the microgel-microgel effective repulsion.
Acknowledgements: The authors thank the MCINN (project MAT2009-13155-C04-02) and the Spanish Ministerio de Economía y Competitividad (project MAT2012-36270-C04-02) for financial support.
[1] Moncho-Jordá, A.; Anta, J. A.; Callejas-Fernández, J., J. Chem. Phys. 2013, (accepted for publication)
[2] Fernández-Nieves, A.; Wyss, H. M.; Mattsson, J.; Weitz, D. A., Microgel Suspensions: Fundamentals and Applications. Wiley-VCH, Weinheim, 2011.
MODELING AND SIMULATIONS 110
O6.4 Non-random adsorption of polyelectrolytes in regularly charged surfaces. From
single chain to multichain deposition Sandra C. C. Nunes*, T. Firmino and A. A. C. C. Pais
Chemistry Department, University of Coimbra, Coimbra, Portugal. *[email protected]
The adsorption of polyelectrolyte chains onto different types of substrates is of great relevance in biological and technological applications, making it the subject of many theoretical and simulation studies. Different aspects ranging from molecular recognition to multilayer deposition have been addressed. Despite the different works devoted to the broad topic of polyelectrolyte adsorption, far less attention has been paid to the study of the factors controlling the spatial distribution of these chains into homogeneous surfaces.
In the present study, Monte Carlo simulations were used to explore the conformation and spatial distribution of uniformly charged polyelectrolytes adsorbing onto homogeneously oppositely charged surfaces. A simple model was adopted, in which polyelectrolytes are represented by spring-bead chains and the charged surface is taken to be a hard planar wall with embedded positively charged fixed hard spheres. Variations were imposed in the surface area, surface charge density and in the number and length of polyelectrolyte chains. The surface charge in the different systems range from partially neutralized to reversed by backbone deposition.
Due to restrictions stemming from the interaction with the surface, polyelectrolytes present, upon adsorption, a conformation different from that in the bulk. This was characterized by the gyration radius, and by the number and length of tails, loops and trains. The spatial distribution of the chains in surfaces was inspected resorting to positioning density maps and to metric approaches based on proximity profiles.
Results indicate non-trivial effects on chain conformation upon adsorption and also non-trivial deposition patterns. As the surface area increases, the polyelectrolyte evolves from distended conformations, only partially adsorbed, to a higher degree of adsorption in which compact conformations are followed by more distended ones. However, high surface charge densities impose, always, some degree of compaction, irrespective of the available space. Moreover for a small number of surface charges, surfaces of lower charge density are able to adsorb more chain segments.
Furthermore, it was found that the potential field created by these regularly charged surfaces is non-uniform, thus promoting a preferential occupancy of some regions. These are selected by a balance between the available space, maximization of the polyelectrolyte/surface electrostatic interaction and minimization of the backbone bending penalty.
When exploring surface coverage with multiple chains, for a particular surface area, adsorption occurs, tendentially, with a minimal effect upon the bulk conformation, in configurations in which chain ends play a major role in the organization of the backbones upon deposition. Moreover, adsorption into the most favorable regions of the surface overrides, to a large degree, interchain repulsion.
Acknowledgements: This work was supported by FEDER funds through the COMPETE program - Programa Operacional Factores de Competitividade - and by National funds through Fundação para a Ciência e Tecnologia (FCT) under the Project PTDC/QUI-QUI/101442/2008 (COMPETE: FCOMP-01-0124-FEDER-010831). Sandra C. C. Nunes gratefully acknowledges the post-doctoral research grant SFRH/BPD/71683/2010 assigned by the Fundação para a Ciência e Tecnologia (FCT).
MODELING AND SIMULATIONS 111
O6.5 A molecular insight on new vesicular systems formed by self-assembly of sterols
and quaternary ammonium surfactants J. Faraudo1,*, L. Ferrer-Tasies1,2, E. Moreno-Calvo1,2, M. Cano-Sarabia1,2, M. Aguilella-Arzo3,
A. Angelova4, S. Lesieur4, S. Ricart1, N. Ventosa1,2, J. Veciana1,2
1Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Esfera UAB; Campus UAB s/n; E-08193 Cerdanyola del Vallès, Spain
2CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN) 3Biophysics Group, Department of Physics, Universitat Jaume I, E-12080 Castelló, Spain
4Equipe Physico-chimie de Systèmes Polyphasés, UMR CNRS 8612, Univ Paris-Sud, 92296 Châtenay-Malabry, France.
Thermodynamically stable nanovesicular structures are of high interest for academia and industry in a wide variety of application fields, ranging from nanomaterials preparation to nanomedicine.
In this contribution, we discuss a novel nanovesicular system, that we have called quatsome [1], which has outstanding stability with time and temperature.. A quatsome is made by a closed self-assembled bilayer of an amphiphilic bimolecular building-block. This building block is made by the self-assembly of a quaternary ammonium surfactant and a sterol molecule (for example a CTAB and a colesterol). As pure species, these surfactants (e.g. CTAB) form micelles and insoluble cholesterol forms crystals in water. However, our molecular dynamic simulations reveal a synergy between CTAB and cholesterol molecules, which makes them self-assemble into bimolecular amphiphiles and then into bilayers in the presence of water. These bilayers have the same structure of those formed by double tailed unimolecular amphiphiles.
In addition to MD simulations, we will also discuss quasi-elastic light scattering (QELS), cryogenic transmission electron microscopy (cryo-TEM) and turbidity (optical density) measurements of Quatsomes. Figure caption: Illustration of a Quatsome. Left: scheme showing the bimolecular assembly formed by a CTAB surfactant and a cholesterol molecule. The colored areas illustrate the shapes of the individual molecules (note that the global bimolecular self-assembled entity has a shape appropriate for vesicular self-assembly). Center:
Cryo-TEM image of Quatsomes, an scheme of the supramolecular organization is also shown (right).
[1] Ferrer-Tasies, L.; Moreno-Calvo, E.; Cano-Sarabia, M.; Aguilella-Arzo, M.; Angelova, A.; Lesieur, S.; Ricart, S.; Faraudo, J.; Ventosa, N.; Veciana, J., Langmuir (Submited).
MODELING AND SIMULATIONS 112
O6.6 Internal and free energy in a pair of like-charged colloids. Confined and bulk
fluids Alejandro Cuetos1,*, Juan A. Anta1 and Antonio Puertas2
1Departamento de Sistemas Físicos, Químicos y Naturales, Universidad Pablo de Olavide, 41013 Seville, Spain.
2Departamento de Física Aplicada, University of Almería, 04120 Almería, Spain *[email protected]
The effective interaction between two colloidal particles in a bath of monovalent co- and counterions is studied by means of lattice Monte Carlo simulations with the primitive model. The internal electrostatic energy as a function of the colloid distance is studied fixing the position of the colloids. The free energy of the whole system is obtained introducing a bias parabolic potential, that allows us to sample efficiently small separations between the colloidal particles. This method has been applied to confined and non-confined situations. In the non-confined case, for small charges,both the internal and free energy increase when the colloids approach each other, resulting in an effective repulsion driven by the electrostatic repulsion. When the colloidal charge is large enough, on the other hand, the colloid-ion coupling is strong enough to form double layers. The internal energy in this case decreases upon approaching the colloids because more ions enter the double layer. This attractive contribution to the interaction between the colloids is stronger for larger charges and larger ionic concentrations. However, the total free energy increases due to the loss of ionic entropy, and resulting finally in a repulsive interaction potential driven by the entropic contributions. For fluids with strong confinement in one of the dimensions of the simulations box, similar results have been found. Although there are numerical differences with the bulk case, the qualitative behavior is basically the same. In the range of charge studied and in a bath of monovalent ions, attraction between like charged colloids has not been found. The overall behavior is captured by the DLVO theory qualitatively, and a comparison is made with the functional form predicted by the theory, showing moderate agreement.
BIOTECHNOLOGICAL APPLICATIONS 113
O7.1 Multiplexed Plasmon Sensor for Rapid Label-free Analyte Detection Rubén Ahijado-Guzmán1, Christina Rosman1, Janak Prasad1,2, Andreas Neiser1,
Andreas Henkel1, Jonathan Edgar1, and Carsten Sönnichsen1,* 1Institute of Physical Chemistry, University of Mainz, Duesbergweg 10-14, D-55128 Mainz
2Graduate School Materials Science in Mainz, Staudingerweg 9, D-55128 Mainz *[email protected]
Here we present a new experimental method for the detection (qualitative and quantitative) of multiple analytes simultaneously in complex biological samples by using randomly deposited gold nanorods in a microfluidic flow cell. Through the use of four distinct proteins as targets, we demonstrate the feasibility of the concept. Our technique has the potential to simplify multiplexed detection and reduce the costs of each sensor to negligible dimensions. Using our engineered gold nanorods as a plasmonic nanosensor, only a few microliters of sample are needed for the fast detection with the detection limit down to 1 nanomolar. In addition, we show the reusability our sensors for multiple assays. Our technique can also be potentially upscaled for detection of several hundreds of analytes, which makes it ideal platform for rapid detection of some kinds of low abundant proteins at a fairly reasonable cost.
Figure caption: Sensor fabrication strategy and detection method. a, To fabricate a mapped or position
encoded sensor, aptamer coated nanoparticles 1…i were deposited consecutively (recording their positions after each step) in a microfluidic flow cell. b, an unmapped sensor is produced by mixing all particles 1…i before deposition. Hence, position encoding is not available. c, To detect an analyte in a
solution, it is injected into the flow cell (in both cases), the targets bind specifically to their corresponding aptamer coated nanoparticles and induce shifts res in their plasmon resonances.
Acknowledgements: This work was financially supported by the ERC grant 259640 (“SingleSense”). J. P. was financially supported by the graduate school of excellence Materials Science in Mainz.
BIOTECHNOLOGICAL APPLICATIONS 114
O7.2 Development of DODAB:MO Liposomes for Gene Delivery
J. P. Neves Silva1, A. C. N. Oliveira2, A. F. C. Gomes2 and M. E. C. D. Real Oliveira1,*
1CFUM (Centre of Physics of the University of Minho), Department of Physics, University of Minho,
Campus of Gualtar, 4710-057 Braga, Portugal. 2CBMA (Centre of Molecular and Environmental Biology), Department of Biology, University of Minho,
Campus of Gualtar, 4710-057 Braga, Portugal. *[email protected]
The artificial introduction of nucleic acids (NA) into mammalian cells (transfection) has become, in recent years, a well-established procedure in basic and applied research, which allowed the study of gene function and regulation [1]. The advances in this area have made possible the use of these methods for gene-based medicines, which constitute alternative therapeutic approaches. One of the most prominent methods is lipofection that uses cationic liposome/NA complexes (a.k.a. lipoplexes) for the complexation, transport and release of therapeutic sequences into target cells. Although yielding lower transfection efficiencies compared with viral gene delivery, lipofection vectors have been chosen for medical applications due to their low mutational or toxicological risk.
Dioctadecyldimethylammonium Bromide (DODAB)/Monoolein (MO) liposomes have recently been described as a new promising alternative to common transfection reagents, due to the pioneering application of MO as helper lipid in lipoplex formulations. MO is not only responsible for the fluidification of DODAB’s gel lamellar phase at physiological temperature, but also for the formation on inverted bicontinuous cubic structures at MO’s molar fractions above 0.5 [2]. This behavior, which was already reported in the absence of NA [2], becomes essential to modulate and optimize pDNA/DODAB/MO physicochemical properties for optimal in vivo application [1]. Indeed, variation of lipoplex properties have shown to affect the interaction with different extracellular components and their cell uptake and trafficking [1,3]. The biocompatibility of pDNA/DODAB/MO lipoplexes has also been reported to increase with MO presence in the formulation, supporting the use of this surfactant as new helper lipid in lipofection [1,2,3].
Figure caption: Schematical phase diagram of structural organization pDNA/DODAB:MO lipoplexes.
Acknowledgements: FCT for funding through PTDC/QUI/69795/2006, SFRH/BD/46968/2008, PEst-C/BIA/UI4050/2011 (CBMA) and PEst-C/FIS/UI0607/2011 (CFUM) projects. FEDER for funding through POFC – COMPETE.
[1] Silva, J. P. N., A. C. N. Oliveira, A. C. Gomes, and M. E. C. D. R. Oliveira, Development of DODAB-MO Liposomes for Gene Delivery. In Cell Interaction; S. Gowder, Editions InTech, Rijeka (Croatia), 2012, pp. 245-272.
[2] Oliveira, I. M. S. C., J. P. N. Silva, E. Feitosa, E. F. Marques, E. M. S. Castanheira, and M. E. C. D. R. Oliveira, J. Colloid Interface Sci. 2012, 374, 206-217.
[3] Silva, J. P. N., A. C. N. Oliveira, M. P. P. A. Casal, A. F. C. Gomes, P. J. G. Coutinho, O. M. F. P. Coutinho, and M. E. C. D. R. Oliveira, Biochim. Biophys. Acta 2011, 1808, 2440-2449.
BIOTECHNOLOGICAL APPLICATIONS 115
O7.3 Using AFM to study the complexation of DNA and anionic lipid mediated by
Ca2+ at the air-water interface Germán Luque-Caballero*, Alberto Martín-Molina and Julia Maldonado-Valderrama
Applied Physics Department. Campus de Fuentenueva sn, 18071. University of Granada, Spain. *[email protected]
Langmuir monolayers constitute at present a novel approach to study interaction between lipids and DNA mimicking interactions in membranes with biotechnological applications. Particularly, we have studied the DNA binding to negatively charged phospholipid monolayers mediated by Ca2+ evaluating interfacial adsorption and aggregation phenomena at the air/water interface. To this end, we tracked the changes in the surface pressure-area isotherms induced by the presence of both Ca2+ and DNA in the subphase which is displaced to higher areas at low surface coverage. Gibbs elasticity of these monolayers shows also a dramatic decrease caused by the complexation with DNA in the presence of Ca2+ and suggests additional rearrangements occurring in the monolayer. Finally, Langmuir-Blodgett transfer to solid supports enables visualization of the system by means of atomic force microscopy (AFM). As a result we demonstrate that the presence of DNA in the monolayer affects drastically the mesostructure forming interfacial aggregates whose size and morphology can be modulated by the surface pressure. The results presented here offer a new perspective into the characterization of anionic lipoplexes by the use of LB-AFM to follow the interfacial aggregation process and to characterize the morphologies of the different aggregates observed. These results can contribute to improve the function and stability of lipid vectors for gene therapy purposes.
Figure caption: A) DPPC/DPPS 4 :1 surface pressure-area isotherms. B) AFM images of phospholipid/Ca2+/DNA interfacial aggregates in a Langmuir-Blodgett monolayer transferred
at � = 25 mN/m.
Acknowledgements: This work has been sponsored by Junta de Andalucía-P09-FQM-4698. Other projects are acknowldeged: EU-FP7-PERG07-GA-2010-268315-ColloDi, JCI-2009-03823, MAT2010-20370 and CEI-Biotic 20F12/16 and Microproyecto2013 (UGR).
[1] Luque-Caballero, G.; Martín-Molina, A.; Sánchez-Treviño, A. Y.; Rodríguez-Valverde, M. A.; Cabrerizo-Vílchez, M. A.; Maldonado-Valderrama, J. Submitted.
BIOTECHNOLOGICAL APPLICATIONS 116
O7.4 Gene Transfer Mediated by Bis-Quaternary Gemini Surfactants Depends on
Complex Architecture A. M. Cardoso1,*, C. M. Morais1, S. G. Silva2, M. L. do Vale2, E. Marques2,
M. C. Pedroso de Lima1,3 and A. S. Jurado1,3
1CNC - Centre for Neuroscience and Cell Biology, University of Coimbra, Portugal 2Centro de Investigação em Química, Department of Chemistry and Biochemistry, University of Porto,
Portugal 3Department of Life Sciences, University of Coimbra, Portugal
The conformational flexibility provided by the spacer and by the double hydrocarbon chains to cationic gemini surfactants has been shown to confer them properties of successful non-viral gene delivery systems, with low toxicity and high nucleic acid protection ability. In this work, a family of gemini surfactants, represented by the general structure [CmH2m+1(CH3)2N+(CH2)sN+(CH3)2CmH2m+1]2Br�, was used to prepare cationic gene carriers. An exhaustive study on the transfection efficiency and cytotoxicity mediated by the complexes formed by each gemini surfactant, either per se or in combination with helper lipids (cholesterol and DOPE), was performed, and their ability to protect the cargo was determined. A physico-chemical characterization of the complexes was addressed to evaluate which properties would be responsible for the vector performance. Large (>3 μm) complexes revealed the highest efficiency to deliver plasmid DNA to HeLa cells, regardless of their surface charge. The occurrence of a phase transition in gemini surfactant dispersions close to physiological temperature and the presence of structural irregularities in surfactant/DNA complexes showed to be correlated with transfection efficiency. On the other hand, only complexes highly fluid at 37ºC exerted high cytotoxicity. Our proposal is that the structural architecture of the complexes guides their membrane interactions and the nature and extent of these interactions underlie the biological activities of the complexes [1]. Therefore, a biophysical study of DNA vector architectural structure represents a step forward towards the rational design of efficient gene delivery systems.
A. B
Figure caption: The presence of a phase transition around 37 ºC in gemini surfactant dispersions (A) correlates with the
transfection efficiency of the corresponding DNA complexes (B).
Acknowledgements: The authors acknowledge Prof. G. Rasteiro, University of Coimbra, for the opportunity to use the zeta sizer device. This work was supported by the grants PTDC/QUI-BIQ/103001/2008, PTDC/DTP-FTO/0265/2012 and PEst-C/SAU/LA0001/2011 funded by FCT and FEDER/COMPETE. A.M.C., C.M.M and S.G.S. are recipients of fellowships from the FCT (SFRH/BD/63288/2009, SFRH/BD/79077/2011 and SFRH/BD/61193/2009, respectively).
[1] Cardoso, A. M. S. et al., Biochim. Biophys. Acta, 2012, 1818, 877–88.
POSTERS SPECIAL SESSIONS
NANOPARTICLES: ORGANIC, INORGANIC AND HYBRIDS 119
PSS01 Luminiscent/Magnetic Liposomes with RGD-conjugate peptide for theranostic
applications M. A. Busquets1,2,*, E. Escribano2,3, J. Queralt2,4, M. Sangrà1, M. Gallardo1,2, and J. Estelrich1,2
1Departament de Fisicoquímica. 2Departament de Farmàcia i Tecnologia Farmacèutica. 3Departament de Fisiologia Humana. Facultat de Farmàcia. Universitat de Barcelona. Avda Joan
XXIII, s/n. 08028 Barcelona. 4Institut de Nanociència i Nanotecnologia (IN2UB), Universitat de Barcelona, C/ Martí i Franquès 1,
08028 Barcelona. *[email protected]
Theranostic nanoparticles have gained increased attention in the last decade because of their potential application in both therapy and diagnosis [1]. Among these particles, magnetoliposomes (MLs) are of particular interest due, in addition, to their lack of toxicity and biodegradability [2]. Bearing in mind the utility of these nanostructures, we have developed a kind of liposomes loading a biocompatible ferrofluid [3, 4] and bearing on the surface a fluorescent probe and polyethylene glycol (PEG) to assure the biological stability. Some of the terminal ends of the PEG chains were derivatized with the tripeptide RGD. The RGD sequence is known to serve as a recognition motiv for some antigens over-expressed on tumor cells surface and on activated platelets. Finally, a drug can be encapsulated in the aqueous inner (if hydrophilic) or inserted in the bilayer (if hydrophobic), and the theranostic system is completed (Figure 1). Depending on the applications to perform, the system can be modified. We have determined the physichochemical properties of the nanoparticles (hydrodynamic diameter, �-potential and magnetization among others) and we have observed their uptake by cells visualized by fluorescent signal. On another hand, we have checked the pharmacological effect in inflammation model in vivo studies. Finally, we have demonstrated the application of the nanoparticles as magnetic resonance imaging contrast agents.
Figure caption: Multifunctional magnetoliposomes.
Acknowledgements: This work was supported by the grant MAT2012-36270-C04-03 from the Spanish Ministerio de Economía y Competitividad.
[1] Janib, S. M.; Moses, A. S.; MacKay, J. A. Adv. Drug Deliv. Res. 2010, 62, 1052-1063. [2] Soenen, S. J.; Hodenius, M.; De Cuyper, M. Nanomedicine 2009, 4, 177-191. [3] García-Jimeno, S.; Escribano, E.; Queralt, J.; Estelrich, J. Int J Pharm 2011, 405, 181-187. [4] García-Jimeno, S.; Estelrich, J. Coll Surf A 2013, 420, 74-81.
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PSS02 Interfacial activity comparison between bare, homogeneous and Janus gold
nanoparticles M. A. Fernandez-Rodriguez1,*, M. A. Rodriguez-Valverde1, M. A. Cabrerizo-Vilchez1,
Y. Song2, S. Chen2, A. Sánchez-Iglesias3, L. Liz-Marzán3 and R. Hidalgo-Alvarez1 1Biocolloid and Fluid Physics Group, Applied Physics Dept., Faculty of Sciences, University of
Granada, 18071 Granada (Spain). 2Department of Chemistry and Biochemistry, University of California, 1156 High Street, Santa Cruz, CA
95064 (USA). 3CIC biomaGUNE, 20009 San Sebastián (Spain).
The interfacial activity of gold nanoparticles can be modified with the use of capping ligands. The interfacial activity was characterized for bare gold nanoparticles (3 nm diameter), hexanethiol-functionalized gold nanoparticles (2 nm-core diameter) and Janus gold nanoparticles (2 nm-core diameter) composed of two regions of different hydrophilic character: hexanethiol and 2-(2-mercapto-ethoxy)ethanol) [1,2]. THF was used as an extension agent and the compression isotherms of each studied nanoparticle at the water-air and water-decane interfaces were performed using the pendant drop technique [3] for different particle concentrations (Fig. 1). The particles were aggregated at the water-air and water-decane interfaces in sizes of hundreds of nanometers up to micrometers.
Figure caption: Water-decane interfaces with 1.66·1012 (left) and 33·1012 (right) Janus gold nanoparticles
deposited at the interface.
Acknowledgements: This study was supported by the ``Ministry of Science and Innovation'' (project MAT2011-23339) by the ``Junta de Andalucía'' (projects P08-FQM-4325 and P10-FQM-5977), and by US National Science Foundation (DMR-0804049). Authors thank to Dr. J.A. Holgado-Terriza, programmer of the software Dinaten used for surface tension measurements.
[1] Pradhan S.; Xu L.; and Chen S., Janus nanoparticles by interfacial engineering, Adv. Funct. Mater. 2007, 17, 2385-2392.
[2] Pradhan S.; Brown L.; Konopelski J.; and Chen S., Janus nanoparticles: reaction dynamics and noesy characterization, J. Nanopart. Res. 2009, 11, 1895-1903.
[3] Torcello-Gómez A.; Maldonado-Valderrama J.; Gálvez-Ruiz M. J.; Martín-Rodríguez A.; Cabrerizo-Vílchez M. A.; Vicente J., Surface rheology of sorbitan tristearate and -lactoglobulin: Shear and dilatational behavior, J. Non-Newton Fluid 2011, 166, 713-722.
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PSS03 Growth of metal sulfides on polymer beads: a starting point for nanocapsules
Márcia C. Neves1,*, Mariana M. Silva1, Diogo Lopes1, Tito Trindade1
1CICECO and Chemistry Department, University of Aveiro, 3810-193 Aveiro, Portugal *[email protected]
The preparation of hollow inorganic capsules of defined shape, composition and with tailored properties is of great scientific and technological interest. Inorganic hollow capsules have a void that can act as storage space to encapsulate various substances. These materials have great impact in various technologies, including the encapsulation and controlled release of drugs.
As an extension of the single source route to produce nanomaterials,[1] we have developed a technique to perform nanocoatings of metal chalcogenides on diverse types of inorganic substrates.[2,3] In this method, metal alkyldithiocarbamate complexes are used as single-molecule precursors and at mild temperatures, in order to modify in situ the surface of substrates by the respective metal chalcogenide. Here, we communicate our results on the adaptation of this method to the use of synthetic polymer beads as substrates for the attainment of polymer/metal sulfide nanocomposites and in which the polymer can be used as a sacrificial template. Therefore these composite structures were investigated as precursors to produce hollow capsules that carry an organic dye, regarded as a drug model, whose release behavior was monitored in diverse experimental conditions.
Acknowledgements: M.C. Neves thanks Fundação para a Ciência e Tecnologia (FCT) for the grant SFRH/BPD/35046/2007. The authors acknowledge FCT (Pest-C/CTM/LA0011/2011), FSE and POPH for funding.
[1] Trindade, T.; O’Brien, P., Adv. Mater., 1996, 8, 161-163. [2] Monteiro O.C.; Esteves, A.C.C.; Trindade, T.; Chem. Mater. 2002, 14, 2900-2904 [3] Neves, M. C.; Monteiro, O. C.; Hempelmann, R.; Silva, A. M. S.; Trindade, T.; Eur. J. Inorg. Chem.,
2008, 4380-4386
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PSS04 Synthesis and modification of metal nanoparticles in organic medium for
plasmonic applications Lakshminarayana Polavarapu1,*, and Luis M. Liz-Marzán1,2,3
1BioNanoPlasmonics Laboratory, CIC biomaGUNE, Paseo de Miramón 182, 20009 Donostia, Spain
2Ikerbasque, Basque Foundation for Science, 48011 Bilbao, Spain 3Departamento de Química Física, Universidade de Vigo, 36310 Vigo, Spain.
Metal nanoparticles, in particular gold and silver nanoparticles have received significant attention in nanotechnology research because of their ability to manipulate the light1 by means of strong surface plasmon resonances, which makes them suitable candidates for enhanced optical sensing of chemical and biological species for detection, diagnosis, plasma enhanced solar cells and catalysis.[1,2] The plasmonic properties of Au and Ag NPs strongly depend on their size and shape [3] and therefore controlling the morphology and monodispersity of NPs is very important for practical applications. Although significant progress has been made in the synthesis of metal NPs in polar organic solvents, little has been advanced toward shape-controlled synthesis in non-polar solvents. The preparation of NPs in organic medium has several advantages such as monodispersity, large scale synthesis, organic catalysis and many more. In this communication, we present an overview of the synthesis of plasmonic NPs of different shapes in organic medium. We present in particular our recent results on the simple synthesis of nearly monodisperse single crystalline Ag nanocubes in organic medium by using oleylamine as both reducing and capping agent [4]. Mechanistic studies based on the time dependent evolution of Ag NPs revealed that oxidative etching of multiply twinned Ag NPs that formed in the initial stages resulted in single crystalline Ag nanocubes. We have further demonstrated the galvanic replacement reaction with HAuCl4 in organic medium to prepare hydrophobic hollow Au-Ag nanocages with tunable localized surface plasmon resonances. The SERS enhancing properties of such nanocages will be presented.
Metal NPs prepared in organic medium: (a) Ag nanoparticles, (b) Ag nanocubes, (c) Ag-Au nanocages.
Acknowledgements: Funding is acknowledged from the European Research Council through the Advanced Grant #267867 (PLASMAQUO).
[1] Alvarez-Puebla, R. A.; Liz-Marzán, L. M.; García de Abajo, F. J. J. Phys. Chem. Lett. 2010, 1, 2428. [2] Polavarapu, L.; Liz-Marzán, L. M. Phys. Chem. Chem. Phys. 2013. 15, 5288. [3] Cao, Y. W. C.; Jin, R. C.; Mirkin, C. A. Science 2002, 297, 1536. [4] Polavarapu, L.; Liz-Marzan, L. M. Nanoscale 2013. DOI: 10.1039/C3NR01244A.
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PSS05 Metallic Janus particles
D. Rodríguez-Fernández1,2,*, J. Pérez-Juste2, I. Pastoriza-Santos2, and L. M. Liz-Marzán1,2,3
1Center for Cooperative Research in Biomaterials (CIC BiomaGUNE), Paseo de Miramón 182, 20009, San Sebastián, Spain.
2Departamento de Química Física, Universidad de Vigo, 36310 Vigo, Spain. 3 Ikerbaske, Basque Foundation for Science, 48011 Bilbao, Spain
The fabrication of particles with multiple surface compositions and functionalities or patchy particles has become a hot topic due to their interesting properties and potential applications in a wide variety of fields. Janus particles belong to a special type of patchy particles that exhibit only one patch that covers half of a sphere. The use of a metallic component provides these particles with new properties making them interesting for applications in catalysis, optical imaging or surface enhanced Raman scattering (SERS) spectroscopy, among others.[1]
In this communication we describe the main synthetic approaches to obtain metallic Janus particles, their properties and applications. We focus on asymmetric particles with a gold patch such as semishells, semicapsules or Janus stars, interesting from the optical point of view, due to the presence of localized surface plasmon resonances.[2]
Acknowledgements: This work was funded by the European Commission FP7 project Nanodirect (No. CP-213948) and the European Research Council Advanced Grant PLASMAQUO (No. 267867). D.R.-F. acknowledges the Spanish Miniserio de Educación Cultura y Deporte for an F.P.U. scholarship.
[1] Rodríguez-Fernández, D.; Liz-Marzán, L. M.; Part. Part. Syst. Charact. 2013, 30, 46–60 [2] Rodríguez-Fernández, D.; Pérez-Juste, J.; Pastoriza-Santos, I.; Liz-Marzán, L. M.; ChemistryOpen
2012, 1, 90–95
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PSS06 Oil-in-Water microemulsions for the synthesis of CeO2, CuO, and CuO/CeO2
nanoparticles and their use as photocatalysts Margarita Sánchez-Domínguez1,*, Andrea V. Vela-Gonzalez1, Kelly Pemartin2, Conxita Solans2, Sergio A. Pérez-García1, César C. Leyva-Porras1 and Isaías Juárez-Ramírez3
1Centro de Investigación en Materiales Avanzados (CIMAV), Unidad Monterrey, GENES-Group of Embedded Nanomaterials for Energy Scavenging, Alianza Norte 202, Parque de Investigación e
Innovación Tecnológica, 66600 Apodaca, N.L., México. 2Instituto de Química Avanzada de Cataluña, Consejo Superior de Investigaciones Científicas (IQAC-
CSIC) and CIBER en Biotecnología, Biomateriales y Nanomedicina (CIBER-BBN), Jordi Girona 18-26, 08034 Barcelona, Spain.
3Departamento de Ecomateriales y Energía, Instituto de Ingeniería Civil, Facultad de Ingeniería Civil, Universidad Autónoma de Nuevo León, Cd. Universitaria, 66451 San Nicolás de los Garza, N.L. México
Introducing different metals into CeO2 affects its characteristics, and in particular the oxygen vacancies, which in turn determine some of its properties such as oxygen storage capacities, which are important for several applications. A method based on oil-in-water (O/W) microemulsions as confined reaction media was recently developed for the preparation of metallic and metal oxide nanoparticles [1, 2]. The advantage of this new approach is the use of water as a continuous phase, more environmentally friendly than organic solvents generally used in the traditional water-in-oil (W/O) microemulsion method. In this study, the synthesis of a hybrid oxide material based on Cerium (Ce) and Copper (Cu) using the O/W microemulsion reaction method has been explored; the pure oxides (CeO2 and CuO) were synthesized and characterized as well for comparison purposes. The nanoparticles were characterized by X-Ray Diffraction (XRD), High Resolution Transmission Electron Microscopy (HRTEM), Scanning Electron Microscopy (SEM), BET, TGA/DSC, XPS and diffuse reflectance spectroscopy. Cu/Ce molar ratio from 5/95 to 30/70, resulted in mixed Cu/Ce oxide in which Cu appear to be either incorporated in the crystal structure of cubic CeO2, or very well dispersed. At Cu/Ce molar ratio (50/50), an excess CuO phase was also obtained. The bandgap of the materials was determined as a function of copper content and it was found that it decreased as Cu content increased. Although the use of individual materials CeO2 and CuO as photocatalysts has been reported in the literature, and mixed CeO2/CuO materials have been synthesized by several methods and used as catalysts in reactions such as the Water Gas Shift, this mixed oxide has not been evaluated as photocatalyst. Therefore, and given the dependence of the bandgap on the composition of the mixed oxide, the synthesized materials were evaluated as photocatalysts for the degradation of an organic dye as model contaminant. Acknowledgements: We are grateful to CONACYT for financial support (CB project No. 166649 and Proyecto de Redes Temáticas No. 194451). We also acknowledge Josué A. Aguilar, Alberto Toxqui and Nayeli Pineda (CIMAV, S.C.) for their technical assistance.
[1] Sánchez-Domínguez, M.; Boutonnet, M.; Solans, C. J. Nanoparticle Research 2009, 11, 1823-1827 [2] Sánchez-Domínguez, M.; Pemartin, K.; Boutonnet, M. Curr. Opin. Colloid Interface Sci. 2012, 17,
297-305.
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PSS07 Preparation of organic solvent resistant nanocarriers from O/W nano-emulsions
as templates Silvia Vílchez-Maldonado, Ricardo Molina, Jordi Esquena and Gabriela Calderó*
Instituto de Química Avanzada de Cataluña (IQAC), Consejo Superior de Investigaciones Científicas (CSIC). Jordi Girona 18-26, 08034 Barcelona, (Spain) and Centro de Investigación Biomédica en Red
en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN) *[email protected]
The study of nanoparticles has experienced a significant increase due to their wide application fields and the new developments in several areas such as medicine, biotechnology, engineering, etc. A well-known method to prepare nanoparticles is the use of nano-emulsions as templates and subsequent solvent evaporation [1]. Among the nano-emulsion preparation methods, the low energy emulsification methods are of special interest due to the energy savings that they involve [2]. The main objective of this work is the preparation of nanocarriers, resistant to organic solvents, using oil in water (O/W) nano-emulsions as templates. For this purpose, the influence of the incorporation of a sunscreen (2-Ethylhexyl 4-dimethylaminobenzoate) and/or a crosslinking agent (hexamethylene diisocyanate) in the oil phase of a model O/W nano-emulsion, obtained in a previously studied water/Solutol HS15/(7% ethylcellulose in ethyl acetate) system at 25ºC [3], was investigated. The oil/surfactant ratio of the model nano-emulsion was 70/30 and the water content 90wt%. It was found that the incorporation of the sunscreen and crosslinking agents do not produce significant changes in droplet size (hydrodynamic diameter around 180 nm), surface charge (about -20 mV) and nano-emulsion stability, as revealed by dynamic light scattering (DLS), Zeta potential and light backscattering measurements. The nanoparticle dispersions were obtained from the nano-emulsions by the solvent evaporation method and showed similar features, concerning surface charge and stability, to the template nano-emulsions. As expected, the nanoparticle sizes (around 50-60 nm, as observed by TEM) were much smaller than the template nano-emulsions. Moreover, the results revealed that despite of the addition of the sunscreen and the crosslinking agent, the shape and size of the nanoparticles did not show remarkable changes. The nanoparticle analysis by high performance liquid chromatography (HPLC) evidenced that the sunscreen agent was successfully incorporated into the nanoparticles. Further, nanoparticles containing diisocyanate were heated at a temperature of 50 ºC during 24 hours to trigger the crosslinking reaction. The resistance of these nanoparticles to organic solvents was assessed by nanoparticle size measurements as a function of time in mixtures of nanoparticle dispersions with ethanol at different ratios. The data obtained indicate that the ethylcellulose nanoparticles, which are soluble in ethanol, were resistant to this solvent after crosslinking with hexamethylene diisocyanate at any nanoparticle dispersion/EtOH ratio. These results confirm that the selected O/W nano-emulsion is an appropriate template to prepare polymeric nanocarriers and that crosslinking of the nanoparticles endows them with organic solvent resistant features.
[1] Desgoullies, S. et al. Langmuir, 2003, 19, 9504-9510. [2] Solans, C., Solé, I. Opin. Colloid Interface Sci., 2012, 17, 246–254. [3] Calderó, G. García-Celma, M. J. and Solans, C. J. Colloid Interface Sci., 2011, 353, 406-411.
POLYMERS, POLYELECTROLYTES, SURFACTANTS AND GELS 126
PSS08 Interaction between a zwitterionic thiophene based conjugated polyelectrolyte
and surfactants in aqueous solution Telma Costa1,*, Diego de Azevedo1, Matti Knaapila,2 Artur Valente1, Mario Kraft3,
Ullrich Scherf3 and Hugh D. Burrows1
1Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade de Coimbra, 3004-535 Coimbra, Portugal.
2Physics Department, Institute for Energy Technology, P.O. Box 40, 2027 Kjeller, Norway 3Makromolekulare Chemie, Bergische Universität Wuppertal, D-42097 Wuppertal, Germany.
Conjugated polyelectrolytes (CPEs) are advanced materials, which find use in a broad range of applications, such as chemical and biological sensing, charge injection or transport layers, light emitting devices, photovoltaic systems and two photon absorbers.[1] Here, we present the photophysical characterization of a zwitterionic water-soluble polythiophene derivative (P3DEBAHT) in aqueous and in dioxane:water solutions. Zwitterionic CPEs in which the conjugated polymers carry both positively and negatively charged groups can avoid the problem of counter-ions adversely affecting optoelectronic or other properties.[2, 3]
Additionally, the interaction between P3DEBAHT polyelectrolyte and different surfactants was studied using absorption, fluorescence, conductivity and small-angle X-ray scattering (SAXS). The formation of CPE/surfactant complexes is extremely important in terms of modulation of CPE properties and development of new Förster resonance energy transfer systems for sensing or light harvesting. Cationic, anionic and zwitterionic surfactants were able to modulate the photophysical properties of the P3DEBAHT. Above their critical micelle concentration, the CPE displays an increase in its fluorescence quantum yield and a blue shift of the maximum emission wavelength. In contrast, the presence of pentaethylene glycol monododecyl ether, a nonionic surfactant, and the water soluble poly(vinyl alcohol) did not have any effect on P3DEBAHT emission properties. This fact emphasizes the importance of electrostatic interactions on the self-assembly between zwitterionic CPE and surfactants. Conductivity and SAXS measurements were also performed to follow changes in the ionic part of the system and characterize the size and the shape of the self-assemble structures formed.
Acknowledgements: The authors thank FCT, the Portuguese agency for scientific research, which has supported this work through a Postdoctoral Grant to TC (SFRH/BPD/47181/2008). The research leading to the SAXS data has received funding from the European Community's Seventh Framework Programme (FP7/2007-2013) CALIPSO under grant agreement nº 312284.
[1] Liu, B.; Bazan, G. C. Conjugated Polyelectrolytes. Fundamentals and Applications in Emerging Technologies, Wiley-VCH: Weinheim, 2013.
[2] Fang, J., Wallikewitz, B. H.; Gao, F.; Tu, G.; Müller, C.; Pace, G.; Friend, R. H.; Huck, W. T. S., J. Am. Chem. Soc. 2011, 133, 683-685.
[3] Scherf, U., U. Angew. Chem. Int. Ed. 2011, 50, 5016–5017.
POLYMERS, POLYELECTROLYTES, SURFACTANTS AND GELS 127
PSS09 Ionization by pH and anionic surfactant binding gives the same thickening
effects of crosslinked polyacrylic acid derivatives Cláudia M. G. Duarte1,*, Luís Alves1, Filipe E. Antunes1,*, Björn Lindman1, Björn Klotz2,
Axel Böttcher2 & Hans-Martin Haake2 1Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
2BASF Personal Care and Nutrition GmbH, 40589 Duesseldorf, Germany *[email protected]
Physical properties of aqueous solutions of hydrophobically modified cross-linked polyacrylates change quite extensively, as the polymer is charged up. A study is carried out concerning the similarities between two polymer ionization processes, i. e. by pH increment and anionic surfactant addition. The two processes charge the polymer by distinctly different mechanisms. At sufficiently high pH the carboxylic groups of the polymer are all virtually ionized and the polymer is, therefore, fully charged. The effective repulsion among the charged groups due to the entropy of the counterions promotes an increased stiffness as well as an expansion of the polymer particle. We investigate here how the ionization and swelling will be if, instead of high pH, the polymer is placed at low pH conditions but associated to ionic surfactants. Surfactants associate to the polymer both in a non-cooperative way by the binding of individual surfactant molecules and in a cooperative way as micelles since the polymer promotes surfactant self-assembly. This binding leads to a highly charged polymer-surfactant complex and leads to an osmotic swelling as well. The swelling and the gelation were monitored by rheology and dynamic light scattering, of polymer solutions at different pH’s and by adding ionic surfactants at low pH. The results show that ionization by surfactants and by pH lead to approximately the same gelation degree, as can be seen by similar viscosity values. Both processes result in dramatic viscosity increases, up to 8 orders of magnitude. More hydrophobic surfactants, with longer alkyl chain, are shown to be more efficient as enhancers of swelling and gelation. The network that is formed at high pH or at sufficiently high concentration of surfactant can be weakened or even disrupted if monovalent or divalent salts are added, demonstrating the role of counterion entropy.
POLYMERS, POLYELECTROLYTES, SURFACTANTS AND GELS 128
PSS10 The influence of the combination of Fe(III) ions with BPEI and LPEI in DNA
condensation: Physico-chemical characterization and in vitro cytotoxicity testing A. F. Jorge1,*, M. C Morán2, M. P. Vinardell2, R. S. Dias1 and A. A. C. C. Pais1
1Department of Chemistry, University of Coimbra, 3004-535 Coimbra 2Department of Physiology, University of Barcelona, 08028 Barcelona, Spain
E�cient DNA condensation, as well as low toxicity, is required for an e�cient gene delivery vehicle. To this end, we combined polyethylenimine (PEI) and Fe (III) ions probing different charge ratios N/P and Fe(III)/P. Fe(III) proved to enhance the DNA condensation and also decondensation when combined with PEI 1. In the present work, LPEI (2.5 and 25 kDa) and BPEI (1.2 and 10 kDa) were used in conjunction with Fe(III) to investigate the influence of the architecture and charge of the polycation on the ternary system. The degree of binding (UV and agarose gel electrophoresis), size and zeta potential were measured. Also, cytotoxicity and hemolysis studies were conducted to evaluate the influence of PEIs and Fe(III) ions, alone and complexed with DNA, on 3T3 and HeLa cells. The results show that, in the absence of Fe(III) ions, the polycations present different abilities to condense DNA. The addition of Fe(III) ions tend to equalize the charge ratios for DNA condensation, and a more pronounced compaction enhancement is obtained with the polycations with a lower Mw. The DNA-BPEI-Fe(III) system tends to form larger aggregates than DNA-LPEI-Fe(III), but at low concentrations of Fe(III), DNA-PEI-Fe(III) determines similar or even smaller sizes than the DNA-PEI counterparts. The addition of Fe(III) alters the zeta potential of the complexes from ca. -30 mV at N/P 2.5 to +10 mV when Fe/P 7 is added. Finally, the impact of the substitution of PEI chains by Fe (III) ions on cells was analyzed. The results show a decrease in the cytotoxicity of the complexes with DNA-PEI-Fe(III), when compared to PEI-DNA complexes in the same degree of compaction.
Acknowledgements: This work was supported by FEDER Funds through the COMPETE Program “ Programa Operacional Factores de Competitividade (FCOMP-01-0124-FEDER-010831) “ and by National Funds through Fundação para a Ciência e Tecnologia (FCT) under Project: PTDC/QUI-QUI/101442/2008. A. F. Jorge gratefully acknowledges the PhD grant SFRH / BD / 66748 / 2009 assigned by the Fundação para a Ciência e Tecnologia
[1] Jorge A.F.; Dias, R.S..; Pais A.C.C., Biomacromolecules 2012, 13, 3151-61.
SOFT COLLOIDS. SOFT NANOTECHNOLOGY. BIOINSPIRED SYSTEMS 129
PSS11 Characterization of Water/Sodium Dodecyl Sulphate/Propanol/Allylbenzene
Micellar Systems Monzer Fanun*
Colloids and Surface Research Center, Al-Quds University, East Jerusalem 51000, Palestine
Water/n-propanol/sodium dodecyl sulphate/ allylbenzene micellar systems were formulated. The ratio (w/w) of n-propanol/surfactant equals 2/1. The extent of the micellar region as function of temperature was determined. The micellar systems were characterized by the volumetric parameters, density, excess volume, ultrasonic velocity and isentropic compressibility. The micellar densities increase with the increase in the water volume fraction. Excess volumes of the sodium dodecyl sulphate decrease for water volume fraction below 0.3, stabilize for water volume fractions between 0.2 and 0.5 then increase for water volume fraction above 0.5. Excess volumes of the studied micellar systems increase with temperature. Ultrasonic velocities increase with the increase in water volume fraction up to 0.8 then decreases. Ultrasonic velocities increase with temperature for water volume fractions below 0.8 and increase for water volume fractions above 0.8. Isentropic compressibilities decrease with the water volume fraction up to 0.8 then increases. Isentropic compressibilities increase with temperature for water volume fractions below 0.8 and decrease for water volume fractions above 0.8. Structural transitions from water-in-oil to bicontineous to oil-in-water occur along the micellar phase. The particle hydrodynamic diameter of the oil-in-water micellar systems was found to decrease with temperature. In the diluted region nanoemulsion systems were observed. The results presented in this study recommend performing allylbenzene isomerization reactions at water volume fractions above 0.95 or at surfactant contents slightly above the critical micelle concentration and at high temperatures
SOFT COLLOIDS. SOFT NANOTECHNOLOGY. BIOINSPIRED SYSTEMS 130
PSS12 Influence of humic acids as colloidal systems on the stability of xenobiotics
J. C. Mejuto1,*, J. Morales1, O. Moldes1, J. A. Manso2
1Physical Chemistry Department, University of Vigo, 32004 Ourense, Spain. 2Cancer Research Center, 37007 Salamanca, Spain.
In solution, humic substances can form complexes with environmental pollutants [1-3]. It is well known their nature as colloids and their behaviour in solution is quite similar to the micellar aggregates [4]. On the other hand, the pesticides carbofuran and carbofuran-derivatives are widely used in agriculture as systemic insecticide with plenty of adverse effects [5]. An inhibition of the alkaline hydrolysis of 3-hydroxy-carbofuran and 3-keto-carbofuran in the presence of colloidal aggregates derived of humic acids (one type of humic substances) has been observed. The results were rationalized in terms of micellar pseudophase model. These inhibitions represent an increase of half-life time of these xenobiotics. However, non-significant effect upon the carbofuran stability in basic media was found in presence of humic acids.
Figure caption: Pseudophase model upon the basic hydrolysis of carbofuran and carbofuran-derivatives
in humic aggregates.
Acknowledgements: The authors thank the Xunta de Galicia (10PXIB383187PR) for financial support. Jorge Morales thanks the University of Vigo for a research-training grant (P.P. 0022 122I 641.03).
[1] LeBoeuf, E. J.; Weber Jr., W. J., Environ. Sci. Technol. 2000, 34, 3632–3640. [2] Zhou, P.; Yan, H.; Gu, B., Chemosphere 2005, 58, 1327-1337. [3] Prosen, H.; Zupancic-Kralj, L., Environ. Pollut. 2005 133, 517–529. [4] Astray, G.; Garcia-Río, L.; Lodeiro, C.; Mejuto, J. C.; Moldes, O.; Morales, J.; Moyano F., Int. J.
Chem. Kinet. 2010, 42, 316-322. [5] Krol, J.; Romano, J.; Block, E., Am. Chem. Soc., Div. Environ. Chem. 2001, 41, 649-656.
SOFT COLLOIDS. SOFT NANOTECHNOLOGY. BIOINSPIRED SYSTEMS 131
PSS13 Drug Delivery Systems based on diacyl arginine surfactants: preparation,
characterization and evaluation of their biological activity L. Pérez1,*, L. Tavano1, M. R. Infante1, A. Pinazo1, M. A. Manresa2, M. P. Vinardell3,
M. Mitjans3
1Department de Tecnologia Química i de Tensioactius, Institut de Química Avançada de Catalunya, CSIC. Jordi Girona 18, 08034 Barcelona, Spain; 2Laboratori de Microbiologia, Facultat de Farmàcia,
Universitat de Barcelona. Av. Joan XIII s/n, 08028 Barcelona, Spain;3Departament de Fisiologia, Facultat de Farmàcia, Universitat de Barcelona. Av. Joan XIII s/n, 08028 Barcelona, Spain
In the last years our group has prepared new diacyl cationic surfactants based on the amino acid arginine, with different structures (gemini, and glycerolipid), characterized by relevant nontoxic and antimicrobial properties as well as rapid biodegradability. In addition, these surfactants from arginine are extraordinarily active in reducing surface tension. Cationic colloidal systems composed by these arginine based surfactants and membrane additive compounds have been characterized by means of size distribution and zeta-potential measurements.
Gemini surfactants with the shortest spacer chain (C6(LA)2) formed micelles, while aqueous solutions of pure gemini surfactants with longer spacer (C9(LA)2 and C12(LA)2) made up very big aggregates. The addition of phospholipids or cholesterol changed drastically the aggregation behaviour. In the case of C6(LA)2, the incorporation of additives gave rise to the formation of cationic vesicles. For C9(LA)2 and C12(LA)2, this type of additives promoted the formation of smaller aggregates. We also evaluated the hemolysis and the antimicrobial activity of these systems. The capability of disrupting the erythrocyte’s membrane depends on the hydrophobicity of the molecules and the size of aggregates in the solution. The alkyl spacer chain and the presence of additives also play an important role on the antimicrobial activity, and, in general, the interaction with bacteria and erythrocytes is affected by the same parameters.
Figure caption: Chemical structure of gemini (a) and glycerolipid (b) arginine-based surfactants.
The diacyl-glycerol arginine cationic lipids form stable cationic liposomes by themselves. These cationic formulations can encapsulate two different drugs (Ciprofloxacine and 5-Fluorouracil (5-FU)) and the percentage of encapsulated drug depends on the physicochemical properties of the vesicles as well as on the type of drug. The capacity of the systems to vehiculate different molecules was evaluated performing their in vitro drug release profiles. Cationic liposomes without drug have antimicrobial activity and the activity of the encapsulated ciprofloxacine is similar or higher to those of the free drug. These results suggest that our formulations represent a great innovation in the pharmaceutical field, due to their dual pharmacological function: one related to the nature of the vehiculated drug and one related to the innate antibacterial properties of the surfactant-based carriers. Acknowledgement: Financial support from MINECO CTQ2010-14897 and MAT2012-38047-CO2-02 is gratefully acknowledged. Also financial support from Generalitat de Catalunya 2009SGR1331 is gratefully acknowledged.
SOFT COLLOIDS. SOFT NANOTECHNOLOGY. BIOINSPIRED SYSTEMS 132
PSS14 Study of the stability of polyethylenimine-decorated liposomes
Gerardo Prieto1,*, Juan Sabín1, Carmen Vázquez-Vázquez2, Federico Bordi3 and Félix Sarmiento1
1Biophysics and Interfaces Group, Departamento de Física Aplicada, Facultade de Física,Universidade de Santiago de Compostela, Santiago de Compostela, Spain
2 Colloid Chemistry Group. Departamento de Química Física, Universidade de Vigo, Vigo, Spain. 3 Dipartimento di Fisica, Università di Roma “La Sapienza” and CNR-IPCF, Rome, Italy.
The study of the interaction of a cationic polymer as Polyethylenimine (PEI) with phospholipid membranes is of special relevance for gene therapy because the PEI is a potential non-viral vector to transfer DNA in living cells [1]. We have study the stability of different PEI-decorated liposomes as a function of the headgroup of the lipid, the size of the initial liposomes, pH, temperature and the charge ratio R . Results were analyzed using the interaction potential proposed by Velegol and Thwar [2], that takes into account the effect of the nonuniform distribution of the electric charge on the surface of the polyelectrolyte decorated liposomes. The strong buffer capacity of the PEI alters the dependence of the zeta potential of the complex with the PEI concentration. We have demonstrated that using the proper buffer and the proper initial liposome size, a double charge inversion of the PEI-decorated liposomes built up with zwitterionic and anionic lipids can be observed. In such cases, the complexes present a very rich stability behavior with three different ranges of PEI concentration where the system is stable and two ranges where a phase separation occurs. In “stable regions” the aggregation leads to the rapid formation of finite-size stable clusters whose final size depends on the molar charge ratio (R ) between the polymer and the liposome the pH and the temperature. In the “unstable regions” the aggregates keep growing until they eventually flocculate [3].
Figure caption: Different ranges of pH studied depending on the zeta potential of
PEI and DOPC liposomes
Acknowledgements: This work was supported by the Spanish "Ministerio de Economía y Competitividad" (Project MAT2011-26330). J. S. is supported by the “Ángeles Alvariño” Program of the "Xunta de Galicia".
[1] Lungwitz, U.; Breunig, M.; Blunk, T.; Gopferich, A., Eur. J. Pharm. Biopharm. 2005, 60, 247-266. [2] Velegol, D.; Thwar, P. K., Langmuir 2001, 17, 7687-7693. [3] Sabín, J.; Vázquez-Vázquez, C.; Prieto, G.; Bordi F.; Sarmiento, F., Langmuir 2012, 28, 10534-
10542.
SOFT COLLOIDS. SOFT NANOTECHNOLOGY. BIOINSPIRED SYSTEMS 133
PSS15 Novel serine-based gemini surfactants for gene delivery:
physicochemical and compaction studies Sandra G. Silva, Isabel S. Oliveira, M. Luísa C. do Vale and Eduardo F. Marques*
Centro de Investigação em Química, Department of Chemistry and Biochemistry, Faculty of Science, University of Porto (Portugal)
There is a growing need to develop delivery systems that protect and deliver biomolecules effectively to the target cells. In this sense, surfactants are a class of compounds widely used in pharmaceutical industry due to its high versatility and interfacial activity. Amino acid-based surfactants usually have low cytotoxicity, are biocompatible and generally readily biodegradable. For these reasons they are of great interest for biological applications, inter alia as non-viral drug delivery vehicles [1].
Herein, we have developed and studied the aqueous phase behavior and aggregate structure of three novel series of gemini amino acid-based surfactant derived from serine, in which spacers based either on amide, amine or ester bonds were introduced between two amino acid carboxylic acid groups. [2] The compounds have 12 carbons in each tail and in the spacer, with general formula (12Ser)2COO12 (ester bond), (12Ser)2CON12 (amide bond) and (12Ser)2N12 (amine bond). The interfacial properties and self-assembly in water is explored through conductivity and surface tension measurements. The aggregates formed in solution have been characterized by video-enhanced high contrast light microscopy, dynamic light scattering and cryo-SEM, with focus on spontaneously formed liposomes. The interaction and the compaction process of these liposomes with DNA, at different charge ratios, have been further studied by means of dynamic light scattering measurements, fluorescence microscopy and cryo-SEM.
Figure caption: General molecular structures of serine-based gemini surfactants and respective video-enhanced light microscopy images of spontaneously formed liposomes. Bar: 20 μm.
Acknowledgements: We kindly acknowledge the Portuguese Science Foundation (FCT) and FEDER-Compete for financial support through projects PTDC/QUI-QUI/115212/2009 and Pest/C-QUI/UI0081/2011.
[1] Yang, P.; Singh, J.; Wettig, S.; Foldvari, M.; Verral, R. E.; Badea, I., Euro. J. Pharm. Biopharm. 2010, 75, 311-320
[2] Silva, S. G.; Alves, C.; Cardoso, A. M. S.; Jurado, A. S.; Lima, M. C. P.; Vale, M. L. C.; Marques, E. F., Euro. J. Org. Chem. 2013, 1758-1769
SURFACES AND INTERFACES 134
PSS16 Effect of the electrostatic interactions in the nanoparticle patterning using
driven evaporating menisci Diego Noguera-Marín1,*, Carmen L. Moraila-Martinez1, Miguel Cabrerizo-Vilchez1 and
Miguel A. Rodriguez-Valverde1
1Department of Applied physics, Campus Fuentenueva s/n, University of Granada, Spain. *[email protected]
Understanding the mechanisms that control the coating or patterning of nanoparticles over a substrate [1, 2] is actually of great importance. These patterns may be achieved by drying of particle suspensions, being the evaporation the leading mechanism [3]. There are, however, other factors that can alter the particle deposition such as the wettability properties (substrate receding contact angle, hysteresis, contrast between substrate and particle), velocity of contact line, solute concentration or pairwise electrical interactions [4]. In this work we focused on the role of the electrical interactions in the particle deposition on substrates [5]. We performed this study using evaporating menisci formed between two vertical substrates but with driven contact lines, such as reported by Bodiguel et al. [6]. The meniscus configuration is highly useful due to its similarities with the industrial technique known as dip coating [7]. The substrates used were glass slides and PMMA sheets (Goodfellow) and as nanoparticles we also chose glass (40nm, Attendbio) and PMMA (90nm, Microparticles). Electrical interactions were tuned by varying the medium pH with low-ionic strength buffer solutions. We found that the particle-particle and substrate-particle electrostatic interactions were determinant for the final patterning (Figure). However, the substrate receding contact angle (wedge-shape region), rather than the wettability contrast between substrate and particle, could counterbalance the effects produced by the substrate-particle repulsion.
Figure caption: Deposits of glass nanoparticles over glass slides at different pH (different electrical charge).
Acknowledgements: This work was supported by the “Misisterio Español de Ciencia e Innovación” (projet MAT2011-23339) and the “Junta de Andalucía” (projects P08-FQM-4325 and P09-FQM-4698).
[1] Joannopoulos, J. D.; Villeneuve, P. R.; Fan, S., Nature 1997, 386, 143-149 [2] Maenosono, S.; Dushkin, C. D.; Saita, S.; Yamaguchi, Y. Langmuir 1999 15 , 957-965 [3] Deegan, R. D.; Bakajin, O.; Dupont, T. F.; Huber, G.; Nagel, S. R.; Witten, T. A.
Nature 1997, 389, 827–829. [4] Bhardwaj, R.; Fang, X.; Somasundaran, D.; Attinger D., Langmuir 2010, 26, 7833–7842. [5]Moraila-Maríez, C.L.; Cabrerizo-Vilchez, M.A.; Rodruíguez-Valverde, M.A., Soft Matter 2013 9,1664-
1673. [6] Bodiguel, H.; Doumenec, F.; Guerrier, B., Langmuir 2010, 26 , 10758–10763 [7] Diao, J. J.; Sun, J. W.; Hutchison, J. B.; Reeves, M. E., Appl. Phys. Lett.2005, 87, 103113.
SURFACES AND INTERFACES 135
PSS17 Surface enhanced Raman scattering microscopy with substrates fabricated by
Au &Ag “nano-inks” Sergey M. Novikov1,*, Lakshminarayana Polavarapu1, and Luis M. Liz-Marzán1,2
1Bionanoplasmonics Laboratory, CIC biomaGUNE, Paseo de Miramón 182, 20009 Donostia-San Sebastián, Spain
2Ikerbasque, Basque Foundation for Science, 48011 Bilbao, Spain *[email protected]
Light interaction with nanostructured materials and nanostructures gives rise to various fascinating optical phenomena occurring at nanoscale. One of the most remarkable effects in light scattering by metal nanostructures is the strong up to several orders of magnitude and spatially localized on the nanometer scale field intensity enhancement (FE). The FE occurs due to the resonantly excited collective electron oscillations, known as localized surface plasmons (LSPs) [1]. The LSPs have a strong sensitivity to the geometry, material, surrounding medium and configuration of metal nanostructures [2, 3]. The FE are extremely important for the practical applications as sensors, micro-optical devices, and plays a major role in surface enhanced Raman scattering (SERS). One of the applications of SERS is the detection of low molecular concentrations down to a single molecule [4]. Therefore, an important research direction is the design of SERS substrates exhibiting strong, reproducible and robust FE effects. On the other hand, the important requirements to SERS substrates are fast, simple and low-cost fabrication, large and homogeneous sample areas. In this work we report about the fabrication and characterization of uniform and efficient SERS substrates prepared by using Au & Ag nanoparticle inks by solution process. Oleylamine capped gold and silver nanoparticles were prepared by two-phase synthesis, which can be purified and concentrated into viscous solutions similar to printable “inks”. Using such metal nanoparticle ‘‘nano-inks’’, we have demonstrated their applications for large scale fabrication of efficient SERS substrates [5, 6]. These samples were examined using different methods: UV-visible spectroscopy, atomic force and scaning electron microscopy, X-ray photoelectron spectroscopy, and SERS. Using UV-visible spectroscopy we estimated the position of LSPs. By SEM and AFM were examined the particle size, thickness of layer, and uniformity of surface coverage of substrates. SERS was observed with excitation wavelengths of 532 nm and 785 nm using thiolated and nonthiolated Raman probes such as Rhodamine 6G (R6G) and napthalenethiol, homogenously adsorbed on such substrates. The concentration of molecules used in the experiments was below 10-8 M. The obtained Raman images show the homogeneity of the fabricated structures. This results illustrate the great opportunity of these structures as "ideal" SERS substrates. They are easy, fast and cheap to fabricate, cover large, homogeneous areas with controlled position of LSPs and allow to detect low molecular concentrations. Finally, the high reproducibility of the results renders these structures very promising for sensing and biological applications
Acknowledgements: This work has been funded by the ERC through Advanced Grant Plasmaquo
[1] Giannini, V.; Fernández-Domínguez, A. I.; Heck, S. C.; Maier, S.A. Chem. Rev. 2011, 111, 3888. [2] Novikov S. M, Evlyukhin A. B., Kuznetsov, A. I. Beermann J., Chichkov B. N. and Bozhevolnyi S. I., J. Opt. Soc.
Am. B., 2012, 29, 185. [3] Beermann, J., Novikov S. M, Albrektsen O., Nielsen M. G and Bozhevolnyi S. I., J. Opt. Soc. Am. B. 2009, 26,
2370. [4] K. Kneipp, Y. Wang, H. Kneipp, L. T. Perelman, I. Itzkan, R. R. Dasar, and M. S. Feld, , Phys. Rev. Lett. 1997,
78, 1667. [5] Polavarapu L. and Liz-Marzán L. M., Phys. Chem. Chem. Phys., 2013 (In press) [6] Sánchez-Iglesiasa A., Aldeanueva-Potela P., Nia W., Pérez-Justea J., Pastoriza-Santosa I., Alvarez-Pueblaa R.A.,
Mbenkumb B.N., Liz-Marzán L.M., Nonotoday, 2010, 5, 1, 21.
SURFACES AND INTERFACES 136
PSS18 Surface behavior of binary systems consisting of E1(70-87) peptide from HGV-C
virus and various phospholipids M. Pujol*, A. Ortiz, M. Muñoz-Juncosa, J. Prat, V. Girona and M. A. Alsina
Physical-Chemistry Departament. Faculty of Pharmacy. University of Barcelona. IN2UB. Associate Unit to CSIC: Protein and Peptides: physico-chemical studies.
Av. Joan XXIII s/n. Building A, Esc E, 3r. 08028 Barcelona *[email protected]
The infection mechanism of viruses with capsid, such as GBV-C and HIV, is cell penetration through a fusion process with the membrane. The binding of a virion to the target cell is achieved by an anchoring of virus structural proteins to the surface of the cell membrane through some conserved fragments, called fusion peptides (FP). The FP penetrates into the host membrane providing a very close contact between the lipid bilayers of the virus and the cell, leading to their fusion. A line of research was developed on the protective effect of GBV-C virus against the development of AIDS in patients co-infected by HIV and GBV-C [1]. In recent years, our group has been performing in vitro physical and chemical studies with different peptide sequences of GBV-C and HIV-1 FP to ascertain their possible interactions [2, 3]. On the other hand, the role that membrane lipids play in the fusion process of enveloped viruses such as FP HIV-1 is known [4, 5]. E1(70-87) peptide is an 18 amino-acid sequence from E1 structural protein of Hepatitis G virus (GBV-C) which has been demonstrated as an effective inhibitor of HIV-1 leakage in vitro. In this work, information on thermodynamic and packing properties for interactions between E1(70-87) and phospholipids (DMPC, DPPC, DMPG, DPPG and DOPG) was derived from surface-pressure ( -A) measurements and analysis. Brewster angle microscopy (BAM) images supported conclusions on peptide arrangements at the air/water interface (Figure). We also provided fluorescence microscopy images from supported mixed monolayers (LB films) to know about the HIV-1 FP inhibition.
Figure caption: Surface-pressure area isotherm of E1(70-87) peptide on Hepes buffered subphase (pH 7.4) at 23 C and BAM images at different compression pressures. Inset: compressional modulus vs. monolayer pressure.
Acknowledgements: This work was funded by Grant CTQ2009-13969-C02/01/BQU from the Ministerio de Ciencia y Tecnología (Spain). The group was a consolidated research group from the Generalitat de Catalunya (2009SGR560).
[1] Yuxian He et al. J. Biol. Chem. 2008, 283, 11126–11134. [2] Sánchez-Martín, M.J. et al. Biochim. Biophys. Acta 2011, 1808, 2178-2188. [3] Sánchez-Martin, M.J. Et al. J. Phys. Chem. B 2010, 114, 448-456. [4] Bitler, A et al. Ultramicroscopy 2010,110, 694-700. [5] Franquelim, H.G. et al. J. Am. Chem. Soc. 2008, 130, 6215-6223.
SURFACES AND INTERFACES 137
PSS19 Oligomer, protofibrillar and fibrillar aggregates from recombinant Human
Lysozyme: surface properties and cytotoxic effect Eva D. Ruiz1, Guadalupe Burboa2, Josué Juárez1* Pablo Taboada3, Victor Mosquera3, and
Miguel A. Valdes1
1Departamento de Física, Universidad de Sonora, Hermosillo, Sonora México. 2Departamento de Investigación y Posgrado en Alimentos, Universidad de Sonora, Hermosillo, Sonora
México. 3Departamento de Física de la Materia Condensada, Universidad de Santiago de Compostela, Santiago
de Compostela, A Coruña, España. *[email protected]
Proteins represent one of the most versatile and important macromolecules in living system playing important roles in different metabolic pathways for the maintenance of life. The correct biological function of proteins depends of their self-assembly into well-defined highly ordered structures (native state) [1]. On the other hand, protein misfolding and abnormal assembly are related in over 30 human disorders, including Alzheirmer´s disease, type II diabetes mellitus, transmissible spongiform encephalopathy, and so on. The pathology of these human disorders is very likely correlated with self-assembly of amyloidogenic peptides into various forms of aggregates such as oligomers, protofibrils, fibrils and senile plaques [2]. Herein we monitorized the amyloid fibril formation of recombinant Human Lysozyme (rHL) by enhanced fluorescence of ThT, DLS, surface tension measurements, FTIR and AFM. Human lysozyme (HL) is a bacteriolytic enzyme, widely distributed in a variety of tissues and body fluids, as the liver, articular cartilage plasma, saliva, tears and milk. HL has been related in the formation of amyloid deposits in autosomal hereditary systemic amyloidosis [3]. In this regards, we evaluated the toxicity of different rHL aggregates (oligomers, protofibrils, and fibrils) over ARPE-19 cell line.
Figure caption: AFM image of rLH at different incubation time (a) 0 min, (b) 120 min and (c) 600 min
[1] Liu, L.; Zhang, L.; Niu, L.; Xu, M.; Yang, Y.; Wang, C.; ACS Nano 2011 , 5, 6001-6007. [2] Adamcik, J.; Mezzenga, R.; Macromolecules 2012 , 45, 1137-1150. [3] Dumoulin, M.; Johnson, R.J.K.; Bellotti, V.; Dobson, C.M.; Protein Reviews 2007 , 6, 285-308.
a b c
MODELING AND SIMULATIONS 138
PSS20 On the initial-gap dependence of magnetorheological performance under
squeezing flow J. A. Ruiz-López*, R. Hidalgo-Álvarez and J. de Vicente
Department of Applied Physics, Faculty of Sciences, University of Granada, C/ Fuentenueva s/n, 18071-Granada, Spain
Magnetorheological (MR) fluids are field-responsive colloidal suspensions whose mechanical properties change in the presence of a magnetic field. A typical MR fluid could be characterized by its yield stress (i.e. the minimum stress value required for the suspension to flow). Devices involving MR fluids definitely require a high yield stress and it has been reported in the past to be enhanced by non-shearing flows [1]. The dependence of MR fluids on typical parameters such as the iron particle concentration, the magnetic field strength or the medium viscosity were investigated in a previous work and explained in terms of continuous media theories [2, 3]. A strong depedence on the initial gap in parallel plates compression experiments were found.
The initial gap dependence was previously investigated for electrorheological fluids [4]. However, the squeeze flow behavior of MR fluids is different to ER fluids. Importantly, in the latter, the electric field strength changes during the compression test (not in a MR fluid experiment with non-magnetizable plates) and therefore it is not possible to split the electric field strength and the initial gap dependences. Experiments with different initial gaps were done and the wetting properties were tuned in order to investigate the surface tension effect. Surface tension affects the resulting normal force acting on the plates especially at large initial gap separations. Polytetrafluoroethylene coated surfaces were used to correct for this effect. Finally, particle-level simulations were also carried out to be compared with experiments and continuous media theories.
Acknowledgements: This work was supported by MICINN MAT 2010-15101 project (Spain), by the European Regional Development Fund (ERDF) and by Junta de Andalucía P10-FQM-5977, P10-RNM-6630 and P11-FQM-7074 projects (Spain). J.A.R.-L. acknowledges financial support by the “Ministerio de Educación: Becas del Programa de Formación del Profesorado Universitario (FPU)” (AP2010-2144).
[1] Havelka, K. O; Pialet, J. W., CHEMTECH 1996, 36, 36-45. [2] de Vicente, J.; Ruiz-López, J. A.; Andablo-Reyes, E.; Segovia-Gutiérrez, J. P.; Hidalgo-Álvarez, R.,
J. Rheol. 2011, 55, 753-779. [3] Ruiz-López, J. A.; Hidalgo-Álvarez, R.; de Vicente, J., Rheol. Acta 2012, 51(7), 595-602. [4] Tian, Y.; Wen, S.; Meng, Y., Phys. Rev. E 2003, 67, 051501.
BIOTECHNOLOGICAL APPLICATIONS 139
PSS21 How chirality may affect to the self-aggregation pattern of lysine-based cationic
gemini lipids and their interaction with plasmid DNA? Ribbon-type and Cluster-type lipoplexes
Ana L. Barrán-Berdón1,*, Mónica Muñoz-Úbeda1, Clara Aicart-Ramos2, Lourdes Pérez3, Alberto Martín-Molina4, Pablo Castro-Hartmann5, Emilio Aicart1 and Elena Junquera1
1Grupo Química Coloidal y Supramolecular, Dpto. Química Física I y 2Dpto. Bioquímica y Biología Molecular I, Fac. Ciencias Químicas, Universidad Complutense de Madrid, Spain; 3Dpto. Tecnología Química y Tensioactivos, IQAC-CSIC, Barcelona, Spain; 4Grupo de Física de Fluidos y Biocoloides,
Dpto. Física Aplicada, Universidad de Granada, Spain; 4Servei de Microscòpia, Universitat Autònoma de Barcelona, Bellaterra, Spain.
Liposomes formed by several molar fractions of cationic lysine-derived lipid C6(LL)2 and the zwitterionic lipid 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) were mixed with plasmid pEGFP-C3 (pDNA) or linear double-stranded calf thymus DNA (ctDNA) at different charge ratios to form lipoplexes. Lipoplex characterization was carried out by both experimental (electrophoretic mobility/zeta potential, small angle X-ray scattering (SAXS), cryogenic transmission electron microscopy (cryo-TEM) and negatively stained transmission electron microscopy (NS-TEM)), and theoretical approaches. The electrochemical study confirms that, in the presence of the mixed lipids and in contrast with what has usually been found for linear DNA, the plasmid DNA is compacted with a large number of its Na+ counterions, thus yielding a much lower effective negative charge (q-
pDNA) than that for ctDNA (q-
ctDNA), as reported recently by us 1 for other lipoplexes. This finding is revealed as crucial for an optimum and efficient lipoplex preparation, since a lower effective negative charge implies a lower quantity of cationic lipid and, accordingly, a potential lower cytotoxicity. TEM experiments reveal a rich variety of multilamellar nanostructures, from ribbon-type (typically present for chiral lipids) to cluster-type structures (usually found in cationic lipid/DOPE systems), the composition of the mixed liposome playing an important role in the final morphology of the lipoplex. SAXS diffractograms confirm the existence of these two types of multilamellar structures through a deconvolution process of the first peak of diffractograms into two overlapping bands. On the other hand, the theoretical complexation model that works with the renormalized charges of liposomes, DNA, and lipoplexes indicates that when the surface charge of a liposome is large enough, an increase in the cationic/zwitterionic lipid ratio does not imply an enhancement in the DNA complexation, which confirms the crucial role played by the zwitterionic helper lipid 2 .
[1] Muñoz-Úbeda, M.; Misra, S; Barrán-Berdón, A. L.; Aicart-Ramos, C; Sierra, B.; Biswas, J; Kondaiah , P; Junquera, E; Bhattacharya, S; Aicart, E, J. Am. Chem. Soc., 2011, 133, 18014-18017
[2] Barrán-Berdón, A. L.; Muñoz-Úbeda, M.; Aicart-Ramos, C.; Pérez, L.; Infante, M. R.; Castro-Hartmann, P.; Molina-Martin, A.; Aicart, E.; Junquera, E., Soft Matter, 2012, 8, 3368-3380.
BIOTECHNOLOGICAL APPLICATIONS 140
PSS22 Lipid-poloxamer nanoemulsions as potential biological carriers
L. García-Jara1, A. Martín-Rodríguez1, J. A. Marchal-Corrales2, Gema Jimenez2, J. M. Peula-García3,*
1Biocolloids and Fluids Physics Group, Dpt. of Applied Physics, University of Granada, Spain. 2Biopathology and Regenerative Medicine Institute (IBIMER), Biomedical Research Centre, University
of Granada, Spain. 3Dpt. of Applied Physics II, University of Málaga, Spain.
The main objective of this work is the formulation of nanoemulsions able to transport hydrophobic drugs. The prepared capsules of the nanoemulsion have a surfactant shell with different poloxamers and lecithin, and a core of olive oil. The preparation method is based on a high-pressure homogenized emulsion, which is one of the most efficient devices for particle and droplet size reduction. The chemico-physical characterization of the nanocapsules played a major role. In this way, the colloidal stability of the nanoemulsion is an important parameter in order to preserve their biomedical properties. It has been demonstrated that this property can be precisely controlled by the chemical structure of the shell interface. The presence of hydrophilic polymers as poloxamers in the surface influences the colloidal stability of the system improving an anomalous stabilization mechanism that maintains the integrity of these nanocapsules with increasing salt concentration. In addition, the “in vitro” uptake process of the nanocapsules was studied using two different human tumoral cell lines by fluorescence microscopy and flow cytometry experiments, in order to know the influence of the surface chemical structure in this process.
Figure caption: Study of the stability of the different formulated nanoparticles as a function of the time.
Acknowledgements: The authors thank the financial support given by the projects MAT2010-20370 (European FEDER support included, MICINN, Spain), and P07-FQM2496, P10-CTS-6270 and P07-FQM3099 (Junta de Andalucía, Spain).
BIOTECHNOLOGICAL APPLICATIONS 141
PSS23 DODAC:MO:DC-Chol/CHEMS lipoplexes for gene delivery
Odete Gonçalves1,2, Hugo Carvalho1,2, João P. N. Silva2, Andreia C. Gomes2 and M. E. C. D. Real Oliveira1,*
1Centre of Physics (CFUM), Department of Physics, University of Minho, Campus of Gualtar, 4710-057 Braga, Portugal.
2Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Campus of Gualtar,4710-057 Braga, Portugal
Dioctadecyldimethylammonium Bromide or Chloride (DODAX, X representing Br- or Cl- counter ions):1-monooleoyl-rac-glycerol (MO) liposomes have recently been described as new promising alternative to common transfection reagents, due to the pioneering application of Monoolein (MO)as helper lipid in lipoplex structures [1-3]. This work was focused on the development and characterization of lipoplexes based on DODAC:MO liposomes with the inclusion of a cholesterol derivative 3 [N-(N’,N’- dimethylaminoethane)carbamoyl cholesterol (DC-Chol) or Cholesteryl hemisuccinate (CHEMS) in order to improve transfection efficiency. MO, a neutral lipid which tends to form inverted bicontinuous cubic mesophases, seems to function well as a helper lipid since it affects the physicochemical properties of the lipoplexes and interferes with lipoplex-cell interactions. DC-Chol is a synthetic cationic molecule derivate from cholesterol. It is frequently used in liposome formulations due to its biocompatibility, the stability it confers to lipid membranes and the ability to enhance transfection efficiency [4]. CHEMS is another cholesterol derivative, known to increase the fusogenic capacity of lipoplexes when the environmental pH is below the pKa (pH 5.8) by forming a hexagonal phase [5].
The results show that the inclusion of DC-Chol does not significantly affect the physicochemical properties (namely size, stability and surface charge) of the nanoparticles but seems to potentiate transfection efficiency and decrease citotoxicity depending on the molar ratio of each component in the liposomal formulation. DODAC:MO:CHEMS lipoplexes are expected to further improve transfection efficiency due to a higher capacity to fuse with biological membranes in acidic environments such as those found in endosomal pathways and in tumors and inflammatory tissues.
Acknowledgments: This work was supported by FEDER through POFC – COMPETE and by national funds from FCT through the project PEst-C/BIA/UI4050/2011 (CBMA) and PEst-C/FIS/UI0607/2011 (CFUM). We acknowledge spin-off Nanodelivery-I&D in Bionanotechnology for access to specific equipments.
[1] M. E. C. D. Real-Oliveira, et al. “Use of Monoolein as a New Auxiliary Lipid in Lipofection”, International Patent n. WO2010/020935, W.I.P. Organization, 2010. p. 1-27.
[2] M. E. C. D. Real-Oliveira, et al. “Aplicação da Monooleína como Novo Lípido Adjuvante em Lipofecção, in Portuguese Patent n. PT2011/104158, I.N.d.P. Industrial. 2011. p. 1-28.H.
[3] Neves Silva, J. P.; Oliveira, A. C. N.; Casal, M. P. P. A.; Gomes, A. C.; Coutinho, P. J. G.; Coutinho, O. P.; Real Oliveira, M. E. C. D., Biochim. Biophys. Acta, 2011, 1808, 2440-2449.
[4] Balazs, D. A; Godbey, W. T., J. Drug Deliv. 2011, 2011, 326497. [5] Hafez, I. M.; Ansell, S.; Cullis, P. R., Biophys. J. 2000, 79, 1438-1446.
BIOTECHNOLOGICAL APPLICATIONS 142
PSS24 Development and characterization of fluorescent microspheres as a probe for
particle uptake assays by flow citometry Cecilia Sóñora1, Ana Hernández1, Iris Miraballes-Martínez2,*
1Cátedra de Inmunología, Facultad de Ciencias. Universidad de la República (UdelaR). URUGUAY 2Laboratorio de Biotecnología, Polo Tecnológico de Pando, Facultad de Química,
Universidad de la República (UdelaR). URUGUAY *[email protected]
The internalization of microparticles by cells can occur by different mechanisms such as endocytocis, pinocytosis or phagocytosis according to the cell type and the particle properties.The particle uptake by cells can be evaluated by microscopy (optical or confocal) or flow cytometry. Some of these methods use fluorescent probes 1,2 . The objective of this work was the 2- step preparation 3,4 of fluorescent microspheres, their characterization and evaluation as probe in particle uptake assays by two different human phagocytic cells (dTHP-1 and monocytes) with flow cytometry measurements for functionality assays.
The human monocytic leukemia cell line THP-1 (ATCC) was differentiated to macrophage phenotype with 3 days incubation with 100 nM phorbol 12-myristate 13-acetate; differentiated THP-1 (dTHP-1) exhibit a more potent phagocytic ability than non differentiated cells 5 . Monocytes were purified from fresh peripheral blood according to standard procedures.
Monocytes or dTHP-1 cells were mixed with the microparticles in tissue cultures plates in ratios from 1:100-1:1000 and incubated for two hours at 37°C and 4°C, in RPMI 1640 culture medium. After incubation, cells were harvested and analyzed in a FACScalibur flow cytometer (BD Biosciences). The increase in green fluorescence intensity (% MFI) and the percentage of fluorescent cells (ingesting cells) was evaluated in relation with basal condition (4°C). Free particles did not interfere with the forward versus side scatter dotplots, and a gate was used for each analysis to exclude debris and non monocytic cells.
25.2%, 37.3% and 48.4% of monocytes exhibited significant green fluorescence when incubated with particles in the ratios 1:100, 1:500 and 1:1000 respectively. 31.8±8.9% ingesting cells were observed in three independent experiments with dTHP-1 cells, with 412±96 % MFI at 1:1000 cell:particle ratio. No significant difference was observed when the assay was done in presence of human serum (opsonization effect).
Our results show that microparticles are efficiently internalized in a non-opsonized form by two cellular types with different intrinsic phagocytic ability. The selected method of preparation of the fluorescent microspheres allows to obtain this reagent which can be modified for different assays in flow citometry
Acknowledgements: Comisión Sectorial de Investigación Científica, (CSIC) Universidad de la República(UdelaR), URUGUAY.
1 Ambruso, D.R. Phagocyte function. In Phagocyte production and function following burn injury; Peterson, V.A. and Ambruso, DR., Eds.; Austin, TX: RG Landes Company, 1994, pp 60- 92.
2 Nares, S.; Wahl, SM. Monocytes and macrophages, in Measuring immunity, MT Lotze and AW Thomson, E. Elsevier AP; California, 2005; pp 299- 311.
3 Peula, J.M.; de las Nieves, F.J.- Colloids Surf. A: Physicochem. Eng. Aspects 1994, 90, 55-62 4 Hermanson, G.T.- Bioconjugate Techniques, Elsevier, 1996. 5 Daigneault M. et al. Plos One. 2010.5,1,e8668.
POSTERS
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P01 Hybrid corrole-gold nanoparticles
Joana F. B. Barata*, Ana L. Daniel-da-Silva, M. Graça, P. M. S. Neves, José A. S. Cavaleiro and Tito Trindade
Department of Chemistry – QOPNA and CICECO, University of Aveiro, 3810-193 Aveiro, Portugal
Colloidal gold has been used in medicine for a long time; for example it has been reported that the alchemist Paracelsus (1493-1541) prescribed its use in the form of Aurum Potabile as a panacea for a number of diseases and, since the twenty century, it has been used as a pharmaceutical formulation to relieve joint inflammation due to rheumatoid arthritis. More recently, with the advent of nanomedicine, gold nanoparticles have found application in new forms of diagnostic and therapeutic strategies. For example, gold nanoparticles have been investigated as a drug delivery in new approaches for cancer treatment such as in photodynamic therapy.[1] Photodynamic therapy (PDT) is a technique in which light-mediated activation of photosensitizing agents results in the generation of reactive oxygen species which destroy target tissues by inducing apoptosis or necrosis of the malignant cells.
Tetrapyrrolic macrocycles play a central role as adequate photosensitizers for PDT.[1] In this context, and comparatively to other macrocyclic systems such as porphyrins, corrole compounds and their metal complexes have been less investigated. We have been interested in developing new hybrid nanoparticles comprising corrole molecules coupled to inorganic particles in order to evaluate the potentiality of these type of conjugates for PDT.[2] In this communication, we will report the synthesis of hybrid corrole-Au nanoparticles obtained from the in situ reduction of Au(III) in the presence of functionalized corroles. The influence of the chemical functionalization of the corrole molecules on the final properties of the materials has been investigated. As such, the hybrid nanostructures were characterized by adequate techniques that include TEM, FTIR and XPS. Optical experiments have been performed with these materials and the results will be discussed here in the context of their usefulness in PDT.
Acknowledgements: Thanks are due to Fundação para a Ciência e a Tecnologia (FCT, Portugal), European Union, QREN, FEDER and COMPETE for funding the QOPNA and CICECO research units (project PEst-C/QUI/UI0062/2011 and Pest-C/CTM/LA0011/2011). J. F. B. Barata thanks FCT-MCTES (Portugal) for her Post-Doctoral grant SFRH/BPD/63237/2009. A. L. Daniel-da-Silva thanks FCT, FSE and POPH for funding. We thank the RNME (National Electronic Microscopy Network) for SEM facilities.
[1] Jelveh, S.; Chithrani, D. B. Cancers 2011, 3, 1081-1110. [2] Barata, J. F. B.; Daniel-da-Silva, A. L.; Neves, M. G. P. M. S.; Cavaleiro, J. A. S.; Trindade, T. RSC
Adv., 2013, 3, 274-280.
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P02 Optimization of a nanostructured lipid carriers formulation for porphyrin
delivery based on factorial design Liliana Damas1, Carla Vitorino1, João J. Sousa1, Marta Piñeiro2, Alberto A. C. C. Pais2,*
1Centro de Estudos Farmacêuticos (CEF), Faculty of Pharmacy, University of Coimbra, Portugal 2Department of Chemistry, University of Coimbra, Portugal
Nanostructured lipid carriers (NLC) have been studied in the last years for administration through different pathways, playing an important role in drug delivery [1]. In the present work, a central composite design (Figure) was applied to optimize a nanostructured lipid carriers formulation composed of precirol, oleic acid and stabilized by Tween 80®. NLC were produced by hot high pressure homogenization, and evaluated as drug carriers for porphyrins (5,10,15,20-tetraphenylporphyrin and meso-Tetra(4-carboxyphenyl)porphine). The selected independent variables, x1, x2 and x3 comprised emulsifier concentration, liquid:solid lipid ratio, and lipid phase concentration, respectively, while the dependent variables or responses included particle size, polydispersity index and zeta potential.
Figure caption: Central composite design for a three factor experiment [2].
Experimental results of 15 formulations yielded mean particle size ranging from 105 to 534 nm, with a polydispersity index from 0.20 to 0.32, and zeta potential values ranging from -16.9 to -34.5 mV. The liquid:solid lipid ratio constituted the most important parameter, followed by the emulsifier concentration. Higher liquid:solid lipid ratios, as well as higher emulsifier concentrations, induce a decrease in particle size. A positive coefficient indicated that a higher lipid phase concentration leads to an increase in particle size, D. In summary, using a second-order model we obtained: D=182.7–33.7x1–82.8x2+42.1x3–4.2x1x2+4.4x2x3–7.8x1x3+20.8x1
2+43.0x22+17.5x3
2+4.6x1x2x3 and an optimal formulation was determined, with mean particle sizes ranging from 91 to 156 nm, with a polydispersity index from 0.29 to 0.31, and zeta potential values ranging from -31.7 to -37.3 mV. The NLC were able to incorporate the porphyrins under study, with no significant changes in particle size and zeta potential, constituting promising carriers for these compounds. The application of experimental design provided a deeper understanding of the system, and also proved to be a useful tool for the optimization of the nanoparticle formulation.
[1] Vitorino, C.; Carvalho, F. A.; Almeida, A. J.; Sousa, J. J.; Pais, A. A. Colloids Surf. B: Biointerfaces, 2011,84, 117.
[2] Adapted from Armstrong, N. Anthony - Pharmaceutical Experimental Design and Interpretation. 2nd ed. USA: Taylor & Francis Group (2006). ISBN 0-415-29901-2.
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P03 Chitosan or Alginate-coated iron oxide nanoparticles: A comparative study
J. Estelrich1,2,*, J. Castelló1, M. A. Gallardo1,2 and M. A. Busquets1,2
1Departament de Fisicoquímica. Facultat de Farmàcia. Universitat de Barcelona. Avda Joan XXIII, s/n. 08028 Barcelona.
2Institut de Nanociència i Nanotecnologia (IN2UB), Universitat de Barcelona, C/ Martí i Franquès 1, 08028 Barcelona.
The preparation and characterization of stable aqueous suspensions of superparamagnetic iron oxide nanoparticles stabilized with chitosan (CHI) or with alginate (ALG) is reported. Both polymers present many relevant properties: nontoxicity, biocompatibility and biodegradability which ensure their suitability for biomedical applications [1, 2]. Synthesis of particles of iron oxide was carried out via a controlled co-precipitation method [3]. The obtained particles presented a diameter of approximately 12 nm, a value that ensures superparamagnetic properties and their suitability for biomedical applications. The optimal concentration of polymer needed for coating the nanoparticles was determined by adsorption isotherms. When coated with polymers, a comparison between the properties afforded by chitosan and alginate has been performed by measures of the hydrodynamic ratio, �-potential, content of polymer coating the particles by thermogravimetry, high-resolution transmission electron microscopy, magnetic properties and, finally, the stability in biologic media. Moreover, the effect of glutaraldehyde as a chitosan crosslinking agent on the stability of the samples has been tested [4].
ALG-coated nanoparticles presented a mean value of 50-55 nm in diameter, whereas the size of CHI-coated nanoparticles was 80-120 nm. The addition of glutaraldehyde 25% (wt %) reduced considerably the size. Both types of particles showed similar values of saturation magnetization (59.3 emu g-1 for ALG-coated nanoparticles, and 56.8 emu g-1 for the coated with CHI). When nanoparticles were kept in contact with human multi-sera at 37oC, significant differences between both types of nanoparticles were observed. ALG-coated nanoparticles were stable up to nine days, but CHI-coated nanoparticles were stable only for two days. Agglomeration and phase separation were the main effects observed.
Acknowledgements: This work was supported by the grant MAT2012-36270-C04-03 from the Spanish Ministerio de Economía y Competitividad.
[1] Lee, K. Y. Mooney, J. Progr. Polym. Sci. 2012, 3, 106-126. [2] Calero, N., Muñoz, J., Ramírez, P., Guerrero, A. Food Hydrocolloid 2010, 24, 659-666. [3] Berger, P., Adelman, N. B., Beckman, K. J., Campbell, D. J., Ellis, A. B., Lisensky, G. C. J. Chem.
Ed. 1999, 76, 943-948. [4] Monteiro, A. C., Airoldi, C. Int. J. Biol. Macromol. 1999, 26, 119-128.
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P04 Broadband dielectric spectroscopy to study colloidal materials.
E. Galera-Cortés1, J. D. Solier1,*, J. Estelrich2 and R. Hidalgo-Álvarez3
1Departamento de Física Aplicada, Universidad de Extremadura, Avda. de Elvas s/n, 06071 Badajoz, Spain.
2Departament de Fisicoquímica. Facultat de Farmàcia. Universitat de Barcelona. Avda Joan XXIII, s/n. 08028 Barcelona. Spain.
2Institut de Nanociència i Nanotecnologia (IN2UB), Universitat de Barcelona, C/ Martí i Franquès 1, 08028 Barcelona.
3Departamento de Física Aplicada, Universidad de Granada, Campus Fuentenueva, 18071 Granada, Spain.
Dielectric spectra of a aqueous colloidal suspension show several relaxations ranging from DC to GHz frequencies, and the broadband dielectric spectroscopy (BDS) is the experimental technique used to explore this range. This work shows how useful this technique is in order to study the electric behaviour of latex and liposomes. The dielectric spectra of latex show two relaxations. The low-frequency dielectric dispersion (LFDD) is owing to the polarization of the electric double layer around the particles. This is reasonably well fitted by the theoretical expressions given by two models: a simplified standard model (not including anomalous conduction) and a generalized one (including anomalous conduction). The high-frequency dielectric dispersion Maxwell–Wagner (MW) is due to the ionic charges distributed near the surfaces that separate phases with different dielectric constant and conductivity. This relaxation is well adjusted by the theoretical expressions given by Maxwell–Wagner–O’Konski theory. Additionally, it would be an option to include the effects of ion mobility in the Stern layer in order for the values of the � -potential (obtained from electrophoretic and dielectric data) to be compatible with each other. On the other hand, in liposome suspension, the dielectric permittivity spectra show two dispersion regions, for frequencies around 25 and under 0.3 MHz. The first dispersion is attributed to rotational diffusion of zwitterionic phospholipid molecules, and the second one is caused by diffusion of the counterion atmosphere along the liposome surface. The lateral diffusion coefficient (Dlat) was obtained from the dielectric relaxation time of zwitterionic phospholipids in the bilayer. These measurements were performed for different pH values and salt concentrations (KBr), as well as in two different physical phases of the phospholipid: liquid-crystalline and gel. It was analyzed how these factors affect the lateral diffusion of dipolar phospholipids in the bilayer. Therefore, broadband dielectric spectroscopy is a powerful tool to study the phenomena of polarization, conduction, diffusion as well as the electrokinetic properties of a colloidal suspension.
Acknowledgements: This work has been supported by the MICINN MAT 2010-15101 Project (Spain), by the European Regional Development Fund (ERDF). R. Hidalgo-Álvarez thanks the financial support received from CEI-Biotic 20F12/16 and P10-FQM-5977 Project (Spain). J. Estelrich thanks the financial support received from MAT2012-36270-C04-03 Project (Spain).
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P05 Cleaning of dried starch in stainless steel with surfactant solutions containing
micro- and nanoparticles E. Jurado*, Jose M. Vicaria, Otilia Herrera-Márquez, A. Plaza
Departamento Ingeniería Química. Universidad de Granada. Avda Fuentenueva s/n. 18071 – Granada (Spain)
*[email protected] The use of nanoparticles in detergent formulations can enhance their cleaning performance due
to mechanisms based on physico-chemical interactions with the substrate and the soil present in the system, facilitating their removal. In this contribution we analyze the influence of the inclusion of silica particles in cleaning of dried starch .The silica particles were supplied by Evonik Industries AG (Hanau-Wolfgang, Germany), Their surface areas and sizes were 500 m2/g -50 μm, 200 m2/g – 12 nm and 380 m2/g-7 nm.
To evaluate the detergency, gelatinized starch was used to dirty spheres made with stainless steel fibers. The dirty spheres were dried in oven at 60 °C for 12 h. The washing tests were performed in the Bath-Substrate-Flow (BSF) device proposed by [1]. This device simulates a cleaning-in-place system. Several samples are extracted in each experiment at different times. The total amount of soluble carbohydrates in the cleaning solution was analyzed by the colorimetric assay of phenol-sulfuric acid. Response surface methodology was used to analyze the experimental results. The variables assayed were flow (30-60 L/h), pH (7-13), particle concentration (0.1-1 g/L Sipernat 50). The washing was made for 45 min and 40ºC. The detergency (De (%)) was evaluated as De = Wbath·100 / Wstarch, where Wbath is the amount of dirt in the washing bath and Wstarch the total starch added to the substrate at the beginning of the cleaning process. [2]
The results indicate that the inclusion of nanopartícles had no influence on cleaning starch. The most significant variables in the washing process were pH and flow. At pH 7-10, the detergency obtained in the absence of surfactant was next to 0. At pH=13, the detergency was 15,4% with a flow rate of 30 L/h and 30,7% at 60 L/h. Experiments with the surfactant Findet 1214N/23 (ethoxylated fatty alcohol) supplied by Kao Corporation, were also carried out. The detergency obtained in the tests conducted with 1 g/L of Findet 1214N/23 at pH 7-10 was next to 0 again. The detergency obtained in experiments that contains 0,1 g/L of particles was similar to the experiments made without surfactant. However, the detergency is reduced significantly with increasing concentration of particles (1 g/L) (23,3% at 30 L/h and 34,5% at 60 L/h). This result suggests that the surfactant is adsorbed on the Sipernat particles and there is a reduction of the cleaning efficiency. The adsorption of surfactant (Findet 1214N/23) by microparticles made of hydrophilic silica (Sipernat 50) and nanoparticles made of fumed silica (Aerosil 200 and Aerosil 380) was measured by standard tests. The surfactant concentration assayed was 1 g/L and the particle concentration was between 0.1-1 g/L. The surfactant concentration was measured using the iodine-iodide colorimetric method [3]. It was observed to be adsorbed 52% of surfactant by Sipernat 50 and almost 20% by Aerosil 200 and Aerosil 380. This adsorption of the surfactant on the nanoparticles interfere with the washing process, preventing the surfactant from acting on the soil retained in the substrate.
Acknowledgements: The authors are grateful the financial support provided by Spanish and Andalusian Governments through the projects CTM2010-16770 and P07-TEP-02603.
[1] Jurado, E.; Bravo, V.; Bailón, R.; Núnez, J.; Altmajer, D. Método BSF (Baño-Sustrato-Flujo) y dispositivo para la evaluación de la eficacia detersiva y dispersante de tensioactivos, de coadyuvantes de la detergencia y de composiciones de detergentes de superficies duras. Spanish Patent P2002/02364.
[2] Jurado, E., Bravo, V., Altmajer, D., Siqueira, R., Food Hydrocolloids 2011, 25, 647-653 [3] Jurado, E., Fernández-Serrano, M., Núñez, J., Luzón, G., Lechuga, M., Tenside surfactants detergents 2002, 39, nº
5, 154-159.
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P06 Hybrid Magnetic Polymeric Nanoparticles Prepared via Miniemulsion
Polymerization Chariya Kaewsaneha1,2, Pramuan Tangboriboonrat2, Duangporn Polpanich3,
and Abdelhamid Elaissari1,*
1University of Lyon, F-69622, Lyon, France; University Lyon-1, Villeurbanne; CNRS, UMR 5007, LAGEP- CPE; 43 bd 11 Novembre 1918, F-69622 Villeurbanne, France
2Department of Chemistry, Faculty of Science, Mahidol University, Phyathai, Bangkok 10400, Thailand 3National Nanotechnology Center (NANOTEC), Thailand Science Park, PathumThani 12120, Thailand
Magnetic polymeric nanoparticle (MPNP) and/or Janus magnetic nanoparticle (JMNP) consisting of magnetic nanoparticles (MNPs) embedded in polymer matrix were successfully prepared via the miniemulsion polymerization [1,2]. Since the particle nucleation occurs primarily within the monomer droplet, not only the size of particle could be controlled at the beginning but also its morphology was manipulated by using different types of initiator. In this case, MNPs were prepared by the co-precipitation method and then were coated with oleic acid before mixing with styrene and acrylic acid monomers. The MPNP with homogeneous distribution of MNPs (41%) in the polymer matrix was obtained when using potassium persulfate (KPS) as initiator and divinyl benzene as crosslinking agent (Figure A) [2]. To obtain JMNP, an oil soluble initiator 2,2’-azobis(2-isobutyronitrile) was introduced instead of KPS [3]. The controllable phase separation between the polymer matrix and the encapsulated MNPs caused the stable spherical Janus particles containing MNPs (15%) located on one side of polymer particle (Figure B). Both MPNPs and JMNPs could be easily separated by an external magnet.
Figure caption: TEM images of MPNP (A) and JMNP (B) [2].
Acknowledgements: The authors thank and appreciate the research grant (RTA5480007) from The Thailand Research Fund (TRF)/Commission on Higher Education to P.T., and the scholarship from TRF, Mahidol University and French Government through the Royal Golden Jubilee Ph.D. Program (Grant No. PHD/0174/2552) to the PhD student C.K.
[1] Charoenmark, L.; Polpanich, D.; Thiramanas, R.; Tangboriboonrat, P. Macromol Res, 2012, 20, 590. [2] Kaewsaneha, C., Opaprakasit, P., Polpanich, D., Smanmoo, S., Tangboriboonrat, P. J. Colloid
Interface Sci., 2012, 377, 145-152. [3] S. Braconnot, S., Eissa, M.M., Elaissari, A. Colloid. Polym. Sci. 2013, 291, 193-203.
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P07 SERS Performance of Gold Nanostars
J. Langer1,*, A. Shiohara1, A. Sánchez-Iglesias1 and L. M. Liz-Marzán1,2
1Bionanoplasmonics Laboratory, CIC biomaGUNE, Paseo de Miramón 182, 20009 Donostia-San Sebastián, Spain.
2Ikerbasque, Basque Foundation for Science, 48011 Bilbao, Spain *[email protected]
Surface enhanced Raman scattering (SERS) can take place when a molecule is adsorbed on a rough metallic surface or a plasmonic nanostructure and becomes more and more popular as an analytical tool to detect very low concentrations of molecules. Plasmonic Au nanoparticles (NP) offer a great potential for biosensing due to their low toxicity, chemical inertness and plasmon tunability within the near-infrared (NIR) region, which is of advantage for in vivo applications. Au NPs with sophisticated shapes and complex compositions have been fabricated and intensively explored for SERS spectroscopy [1]. Very promising candida-tes for biomedical applications are star-shaped nanostructures [2-5] because of their surface plasmon resonances, which can be tuned into the NIR region by controlling the branch aspect ratio [3] and the strong electromagnetic field enhancement (hot spots) located at the tips [2].
In general, SERS depends strongly on a variety of factors, e.g. the matching of plasmon excitation and Raman laser wavelength, the electronic nature and surface chemistry of the analyte and aggregation state of the analyte-NP system. In order to stabilize, protect and functionalize the NP surface, different polymer coatings or surfactants are used, which can also affect the scattering properties.
In this contribution, we present a systematic and comparative study of the SERS performance of polyvinylpyrrolidone (PVP), polyethylene glycol (SHPEG) and silver (Ag) coated, citrate (cit) and sodium dodecyl sulfate (SDS) stabilized Au nanostars in aqueous solution using dyes and thiols as analytes for two types of binding modes to the bare star surface. The dye molecules astra blue (AB) and rhodamine 6G (R6G) interact with the nanoparticles via electrostatic forces, whereas the thiolated molecules 1-naphthalenethiol (1NAT), mercaptobenzoic acid (MBA), aminothiophenol (ATP) and benzenedithiol (BDT) are covalently bound to Au.
Regardless of the coating type, the strongest SERS signal was observed for AB. PVP coated nanostars show a very good SERS performance and stability with both dyes and thiols. The SERS signals of R6G with PEG coated or SDS-Au nanostars are lower than for PVP coating, and the detection of 1-NAT is not possible. Cit-Au nanostar colloids show high SERS of MBA, ATP or BDT, but are not stable in solution and tend to fast aggregation. Ag coating of the Au nanostar significantly enhances the AB SERS signal compared to the cit-Au nanostar, but without further protection the stability remains problematic.
[1] Burda, C.; Chen, X.; Narayanan, R.; El-Sayed, M.; Chem. Rev. 2005, 105, 1025. [2] Barbosa, S.; Agrawal, A.; Rodriguez-Lorenzo, L.; Pastoriza-Santos, I.; Alvarez-Puebla, R. A.;
Kornowski, A.; Weller, H.; Liz-Marzan, L. M.; Langmuir 2010, 26, 14943. [3] Yuan, H.; Khoury, C.G.; Hwang, H.; Wilson, C.M.; Grant, G.A.; Vo-Dinh, T., Nanotechnology 2012,
23, 075102. [4] Rodriguez-Lorenzo, L.; Krpetic, Z.; Barbosa, S.; Alvarez-Puebla, R.A.; Liz-Marzan, L. M.; Prior, I.
A.; Brust, M.; Integr. Biol. 2011, 3, 922. [5] Schütz, M.; Steinigeweg, D.; Salehi, M., Kömpe, K., Schlücker, S.; Chem. Commun. 2011, 47, 4216.
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P08 PS-PAA-Capped Gold Nanostars as SERS substrate for the detection of
hydrophobic molecules Andrea La Porta1,*, Ana Sánchez-Iglesias1, Marek Grzelczak1 and Luis M. Liz-Marzán1
1Bionanoplasmonics Laboratory, CIC biomaGUNE, Paseo de Miramón 182, 20009 Donostia- San Sebastián, Spain.
Surface-Enhanced Raman Scattering (SERS) is a powerful tool to detect and analyze very small amount of molecules on a metallic substrate. The key aspect of this technique is the strong local enhancement of the incident electric field due to the Localized Surface Plasmon Resonance (LSPR) of metal nanostructures. Star-shaped nanoparticles represent an interesting option for SERS substrate because of the intense electric field enhancement present at the tips and in the areas between two or more adjacent tips (hot spots). In this work, SERS spectra of Oxazine 720 in PS-PAA capped gold nanostars (AuNSs) are presented. We investigated the change in the SERS intensity for different analyte concentrations. The comparison between Raman and SERS spectra shows that the analyte is able to go through the external polymeric sphere and get closer to the AuNSs surface. Further treatments with tetrahydrofuran (THF) vapour reveal a decrease in the signal intensity, this confirming the fact that Oxazine molecules go far away from the AuNSs’ surface because of the concentration gradient.
Figure caption: Gold Nanostars: Invididual (a) and Assemblies (b).
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P09 Comb-Like Acrylic-Based Polymer Latexes Containing Nano-Sized
Crystallisable Domains E. Mehravar*, J. R. Leiza, and J. M. Asua
POLYMAT, University of the Basque Country UPV/EHU. *[email protected]
(Liquid) crystalline domains are known to impart improved mechanical properties for solvent born systems [1]. However, little is known about the synthesis of these domains and their properties in water borne acrylic-based latex particles [2]. These hard and tough domains can be introduced to a polymer matrix by using crystallisable side-chains of the polymer backbone obtained via copolymerization of monomers having long side chains with conventional monomers (comb-like crystalline polymers) [3]. In this work the toughening of the soft acrylic-based latex particles via introducing crystallizable units within the waterborne latex particles was studied. The polymer latexes were synthesized via 2-step miniemulsion copolymerization of a crystallizable long side chain acrylate monomer (stearyl acrylate, SA) and short side chain (meth)acrylates (methyl methacrylate MMA, n-buthyl acrylate BA and Acrylic acid AA) in different strategies. Thermal characterization and mechanical properties of the films prepared from these latexes indicated that the monomer composition and also copolymerization process conditions have significant effects on the crystallinity and the mechanical properties of copolymer latexes. The heat of fusion and crystallinity of the copolymer latexes synthesized with the same copolymerization process decrease with increasing of short side chain (meth)acrylates concentration. The findings suggested that the presence of PSA crystalline domains increases the mechanical properties of the latexes (Figure 1). Conversely, the PSA amorphous states decrease the glass transition temperature and mechanical properties of the copolymer latexes [4].
Figure caption: The stress-strain behavior of latexes synthesized with different monomer composition
obtained from seed (poly stearyl acrylate) miniemulsion copolymerization of short side chain (meth)acrylates (a) and the enlargement of elastic region (b).
[1] Chen, D. S.; Jones, F. N., J. Appl. Polym: Sci. 1988, 36, 141-163. [2] Parker, H. Y.; Merritt, R. F.; Fu, Z.; Ibbitson, S. A.; Gore, R. H.; Wolfersberger, M. A., U. S. Patent
6,552,147, 2002. [3] O'Leary, K.; Paul, D. R., Polymer 2006, 47, 1245-1258. [4] Jordan Jr, E. F., J. Polym. Sci., Part A: Polym. Chem. 1971, 9, 3367–3378.
a b
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P10 Synthesis and photocatalytic properties of titanates nanotubes sensitized by
crystalline Ag2S nanoparticles Márcia C. Neves1,*, A. J. Silvestre2, M. R. Nunes3, O. C. Monteiro4
1Ciceco and Chemistry Department, University of Aveiro,3810-193 Aveiro, Portugal 2Department of Physics and ICEMS, Instituto Superior de Engenharia de Lisboa,
1959-007 Lisboa, Portugal 3CCMM, Department of Chemistry and Biochemistry, Faculty of Sciences,
University of Lisbon, 1749-016 Lisboa, Portugal 4CQB, Department of Chemistry and Biochemistry, Faculty of Sciences,
University of Lisbon, 1749-016 Lisboa, Portugal *[email protected]
Nanostructured materials have become one of the most important research subjects, being established a remarkable development in a wide assortment of scientific fields. Despite all known successes, the control of the materials’ intrinsic properties is still difficult and challenging. The synthesis of nanocomposite materials has been one of the most fruitful methods for accomplish this propose: by combining several materials it is possible to prepare new materials with improved and innovated properties. Titanate nanotubular structures (TNS) are very interesting since they combine the properties and applications of conventional TiO2 nanoparticles (e.g., photocatalytic activity) with the properties of layered titanates (e.g., ion-exchange facility) [1]. Nevertheless, the synthesis of TiO2-based materials either with a broader range of light absorption and/or a lower charge recombination rate would be an important step toward the development of higher efficient photoactive materials [2].
In this works a single source method is described to prepare nanocrystalline Ag2S/TNS, aiming to obtain new nanostructured materials with improved optical and photocatalytic properties. The TNS modification is based on the in situ nucleation of crystalline Ag2S nanoparticles onto the TNS surface. The prepared materials were structural, morphological and optical characterized. The application of these new photoactive materials for pollutants catalytic photodegradation was investigated using the terephthalic acid as the probe molecule to study the quantum yield of hydroxyl radical (•OH) production [3]. The photocatalytic degradation of a model pollutant molecule, phenol, was also investigated and the results will be discussed. Acknowledgements: M.C. Neves thank Fundação para a Ciência e Tecnologia (FCT) for the grant SFRH/BPD/35046/2007. Authors thank FCT for financial support PTDC/CTM-NAN/113021/2009, PEst-OE/QUI/UI0612/2011, Ciência 2007 Programme, FSE and POPH.
[1] Bavykin, D.V.; Wlash, F.C.; Titanate and Titania Nanotubes, synhtesis, Properties and Applications. RSC Nanoscience & Nanothecnology. RSC Publishing: Cambridge, 2010.
[2] Kaneko, M.; Okura, I.; Photocatalysis, Science and Technology, Biological and Medical Physics Series. Kodansha, Springer:Japan, 2010.
[3] Ishibashi, K.; Fujishima, A.; Watanabe, T.; Hashimoto, K.; J. Photochem. Photobiol A 2000 134, 139-142.
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P11 Highly organized plasmonic nanoparticles:
Uniform plasmonic structures as SERS platforms Nicolas Pazos-Perez1,*, Moritz Tebbe1, Ramon Alverz-Puebla2 and Andreas Fey1
1Department of Physical Chemistry II, University of Bayreuth, 95440, Bayreuth, Germany. 2ICREA - Catalan Institution for Research and Advanced Studies, Spain
Surface enhance Raman scattering (SERS) spectroscopy is a powerful ultrasensitive technique which allows detection down to single molecule levels. The production of active SERS substrates is based on the generation of hot spots created by plasmonic nanoparticles. However, the controlled formation of these hot spots is still a challenge in order to produce homogeneous and reproducible SERS intensities over large areas. On the other hand, plasmonic nanoparticles are still in the focus of interest because of their potential use in microelectronics, optical devices, and biomedical applications or to develop new metamaterial properties. Their individual electromagnetic response is highly dependent on the specific size, shape, and surrounding environment of the particles. At the moment, there are different methods which allow us to fine tune the control over these parameters and thus, the materials properties. However, the control over the collective behaviour of these individual particles and their incorporation into new technological devices, relay on the ability to form reproducible organized structures at large scales.
In this work we report novel methods to produce highly organized structures made of plasmonic nanoparticles in a macro-scale range using a completely lithography-free approach. Monolayers, supercrystals, and periodic linear arrays with tuneable width and spacing between lines, were created via spin coating, confinement controlled drying, and their combinations [1-4].
Furthermore, these structures, were effectively use for sensing using surface-enhanced Raman scattering (SERS) spectroscopy showing the good reproducibility of these structures among big areas. This fact, make them perfect candidates as quantitative ultrasensitive SERS substrates due to the controlled formation of hot spots. Which provide high and uniform SERS enhancement over extended areas.
Figure caption: Scanning electron microscopy (SEM) images of different nanoparticles organizations.
[1] Pazos-Perez, N., et al. Soft Matter 2011, 9, 4093. [2] Mueller, M., et al. Langmuir 2012, 28, 9168-9173. [3] Schweikart, A., et al. Chemical Science 2010, 1, 174. [3] Pazos-Perez, N., et al.Langmuir 2012, 28, 8909. [4] Pazos-Perez, N., et al., Angew. Chem. Int. Ed., DOI: 10.1002/anie.20120701.
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P12 Ferromagnetic anisotropic nanostructures for aqueous metal ions uptake Paula C. Pinheiro1,*, Daniela S. Tavares1, Ana L. Daniel-da-Silva1, Cláudia B. Lopes1,
Eduarda Pereira1, João P. Araújo2, Célia T. Sousa2, Tito Trindade1
1Department of Chemistry-CICECO or CESAM, University of Aveiro, 3810-193 Aveiro, Portugal 2IFIMUP and IN, Department of Physics, University of Porto,4169-007 Porto, Portugal
Water contamination by trace non-essential metals is an eco-toxicological hazard of prime interest that has raised the attention of the scientific community. Nanotechnology offers potential solutions for this environmental problem and in fact a number of nanomaterials have been recently investigated as effective sorbents for water remediation and chemical analysis [1]. Recently, we have been interested in developing colloidal magnetic nanoparticles for water purification technologies, the so-called eco-nanomagnets, that could act as sorbents and have the ability for magnetic removal. So far, we have already shown that dithiocarbamate functionalized magnetite particles are highly efficient sorbents for uptake vestigial mercury (II) ions from water by applying a relatively weak external magnetic field [2].
In this communication, we would like to present the latest results achieved with the extension of the work to ferromagnetic anisotropic 1D nanomaterials (e.g. Ni nanowires), and show the possibility of using this 1D nanomaterials, as magnetic sorbents. Ferromagnetic Ni nanowires with cross sections within the range 40-60 nm were prepared using anodic aluminium oxide as the template [3]. Surface modification strategies were then investigated in order to confer thiolate moieties to these particles. The materials were fully characterized for their morphological and magnetic properties. Finally, a series of experiments were carried out aiming to inquire about the efficiency of these nanostructures as magnetic sorbents for mercury (II) in water. The context of application of these nanomaterials will be discussed based on performance comparative studies with other ferromagnetic sorbents, such as functionalized magnetite particles, and their potential impact on the environment.
Figure caption: SEM image of ferromagnetic nickel nanowires
Acknowledgements: The authors thank Fundação para a Ciência e Tecnologia (PTDC/CTM-NAN/120668/2010, Pest-C/CTM/LA0011/2011, Pest-C/MAR/LA0017/2011),), FSE and POPH for funding.
[1] Hernandez-Ramirez, O.; Holmes, S. M., J. Mater. Chem. 2008, 18, 2751–2761. [2] Girginova, P. I.; Daniel-da-Silva, A. L.; Lopes, C. B.; Figueira, P.; Otero, M.; Amaral, V. S.; Pereira,
E.; Trindade, T., J. Colloid Interface Sci. 2010, 345, 234–240. [3] Proença, M. P.; Sousa, C. T.; Ventura, J.; Vazquez, M.; Araújo, J. P., Electrochim. Acta 2012, 72,
215-221.
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P13 PAMAM dendrimers exerted oxidative damage and structural alterations in
green algae and cyanobacteria Ismael Rodea-Palomares1,*, Soledad Gonzalo2, Francisco Leganés1, Eloy García-Calvo3,
Francisca Fernández-Piñas1, Roberto Rosal2,3 1Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid.
E-28049, Madrid, Spain 2Departamento de Ingeniería Química, Universidad de Alcalá,
E-28871, Alcalá de Henares, Madrid, Spain 3Advanced Study Institute of Madrid, IMDEA-Agua, Parque Científico Tecnológico,
E-28805, Alcalá de Henares, Madrid, Spain *[email protected]
The commercial applications of engineered nanoparticles (ENPs) have widely expanded over the last years covering from biomedicine to industrial applications, with a subsequent potencial increased release into the environment in the near future. Poly(amido amine) (PAMAM) dendrimers are "dense star" polymers characterized by a high degree of structural homogeneity, a highly- functionalized terminal surface and a symmetric increase of molecular weight and surface functional groups with their increase in complexity (generation, G). Currently, PAMAM dendrimers have important applications as drug carriers, but they have interesting perspectives in an industrial process that implies a future increase of PAMAM dendrimer production and subsequent release to the environment.
Algae and cyanobacteria are ecologically relevant organisms which are at the base of aquatic food webs and have essential roles in nutrient cycling therefore being especially well suited to study possible ecological impacts of nanomaterials. In our research group we have applied a multi-method approach to understand the toxic mechanism of action of nanomaterials to these organisms. Within this approach, physicochemical properties of nanomaterials on relevant biological media were studied and linked with the biological information from the organisms. The biological characterization of the organisms’ response to ENPs includes techniques such as flow citometry, confocal microscopy and TEM microscopy which allows to link toxicity and metabolic impairments with physiological end-points and structural alterations.
In the present work, the toxicity and possible mechanism of action of native –NH2 terminated and -NH-C-(CH2OH)3 functionalized PAMAM dendrimers from the generations (G) G2, G3 and G4 were evaluated. NH2 terminated PAMAM exhibited a generation dependent toxicity to both cyanobacteria and green algae (being G4 the most toxic one). -NH-C-(CH2OH)3 surface functionalized PAMAM G2 and G3 were not toxic but G4 presented a toxicity similar to that of native G4 -NH2. Toxicity of –NH2 terminated PAMAM seems to be linked with a strong increase of intracellular reactive oxygen species (ROS). The ROS induction is generation-dependent being faster as generation increases. The internalization of –NH2 terminated PAMAM was evaluated by generating fluorescent PAMAM-Alexa Fluor 488 conjugates. The uptake kinetics of PAMAM conjugates was also generation dependent and surprisingly fast with more than 70% of the total dendrimer being internalized in 10 min. Interestingly membrane damage and cytoplasmic content extrusion phenomenon were observed linked with high ROS induction and intracellular accumulation of –NH2 dendrimers.
Acknowledgements- This work was funded by Comunidad de Madrid grants S-0505/AMB/0321 and S-2009/AMB/1511 (Microambiente-CM) and by the Spanish Ministry of Science and Innovation [grant CGL2010-15675, sub-programme BOS].
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P14 Steric Hindrance Induces Cross-like Self-assembly of Gold Nanodumbbells Ana Sánchez-Iglesias1, Marek Grzelczak 1,2, Hamed Heidari Mezerji,3 Sara Bals,3 Jorge
Pérez-Juste,4 Luis M. Liz-Marzán 1,2,4,*
1CIC biomaGUNE, Spain; 2Ikerbasque, Basque Foundation for Science, Spain; 3University of Antwerp, Belgium; 4Universidade de Vigo, Spain;
In the formation of colloidal molecules, directional interactions are crucial for controlling the spatial distribution of the building blocks. Anisotropic nanoparticles facilitate directional clustering via steric constraints imposed by each specific shape, thereby restricting assembly along certain directions.[1] We show that the combination of patchiness (attraction) and shape (steric hindrance) allows assembling gold nanodumbbell building blocks into cross-like dimers with well-controlled interparticle distance and relative orientation (see Figure below).[2] Steric hindrance between interacting dumbbell-like particles opens up a new synthetic approach toward low-symmetry plasmonic clusters, which may significantly contribute to understand complex plasmonic phenomena.
Figure caption: Polystyrene-stabilized nanoparticles undergo gradual clustering upon addition of water to organic solvent. Encapsulation of clusters inside the polymeric micelles induces the crosslike morphology.
[1] Glotzer, S. C.; Solomon, M. J., Nat Mater 2007, 6, 557–562. [2] - - - , L. M.,
Nano Lett. 2012, 12, 4380–4384.
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P15 Noble metal nanoparticles coated with mesoporous materials
Marta N. Sanz-Ortiz1,* and Luis M. Liz-Marzán1,2,3
1Bionanoplasmonics Laboratory, CIC biomaGUNE, 20009 Donostia-San Sebastián, Spain. 2Ikerbasque, Basque Foundation for Science, 48011 Bilbao, Spain.
3Departamento de Química Física,Universidade de Vigo, 36310 Vigo, Spain. *[email protected]
Metal nanoparticles exhibit physical and chemical behaviors that might radically differ from those of the material in bulk. The control of size effects allows the fine tailoring of the nanoparticles characteristics and confers them with a great number of potential applications in many different fields. However, metal nanoparticles tend to aggregate causing a detriment of their properties. Here we present the synthesis of inorganic (mesoporous silica and zeolite crystals) and organometallic (metal-organic frameworks) coatings on noble metal nanoparticles of different shapes and sizes. The coating not only avoids the aggregation of the metal nanoparticles but it also facilitates the incorporation of new functionalities in the system. The large surface ratio of mesoporous materials, the capability of hosting different chemical species inside their pores and the chemical tunability of their surface, make metal nanoparticles coated with these compounds ideal candidates for applications such as catalysis, drug delivery, sensing and molecular targeting.
Acknowledgements: The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013 under grant agreement n° 312184).
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P16 Formation of plasmonic heterostructures via covalent bond chemistry
Ana Belén Serrano-Montes1,*, Marek Grzelczak1 and Luis M. Liz-Marzán1 1Bionanoplasmonics Laboratory, CIC biomaGUNE,
Paseo de Miramón 182, 20009 Donostia-San Sebastián, Spain. *[email protected]
Surface-Enhanced Raman Scattering (SERS) is a powerful technique for chemical and biomedical sensing, which has become a very important application of the field of plasmonics. Metal nanoparticles, as a plasmonic nanobjects, exhibit suitable properties for SERS enhancement.Specifically, branched nanoparticles, such as gold nanostars, are better candidates for SERS than regular spherical particles. [1]This is because the nanostar serves as a nanoscale antenna that increases the extinction cross section and the electromagnetic field enhancements of the tip plasmons. [2]It is well known that particle-aggregation gives rise to higher enhancement factors as compared to single particles because of hot spot formation. [3]However, this conventional method of generating hot spots is hard to control experimentally. We have explored covalent bond chemistry for the formation of complex heterostructures consisting of gold nanostars and nanospheres. The results show that these structures are promising candidates for biosensing applications.
[1] Rodriguez-Lorenzo, L.; Alvarez-Puebla, R. A.; García de Abajo, F. J.; Liz-Marzán, L. M., J. Phys. Chem. C. 2010, 114, 7336-7340.
[2] Haom, F.; Nehl, C. L.; Hafner, J. H.; Nordlander, P., Nano Lett. 2007, 7, 735-732. [3] Esenturk, E. N.; Walker, A. R. H., J. Raman Spectrosc. 2009, 40, 86-91.
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P17 Various Strategies of Gold Nanostar Synthesis for SERS Applications
Amane Shiohara1, and Luis M. Liz-Marzán1.2.3,*
1CIC BiomaGUNE, Paseo Miramón 182, 20009 Donostia-San Sebastían, Guipúzcoa, Spain 2Ikerbasque, Basque Foundation for Science, 48011 Bilbao, Spain
3Universidade de Vigo, 36310 Vigo, Spain *[email protected]
Gold nanoparticles have been considered as strong candidates as nano-carriers or sensing devices for various applications due to their Surface Plasmon Resonance. Recently the research on anisotropic gold nanoparticles has received increasing attention due to their unique characteristics. Especially star shaped nanoparticles are known to have higher efficiency in Surface Enhanced Raman Spectroscopy (SERS) or Photothermal therapy compared to nanoparticles of spherical shape due to the high electromagnetic fields generated at their tips. However, it is still a challenge to establish the synthesis that can be biocompatible and also can produce high quality nanostars. Previously several nanostar syntheses have been proposed including seed-less growth and seed-mediated growth [1-5]. Recently Vo-Dinh et al. discovered that silver ions can also be used as the growth control factor to produce gold nanostars in a surfactant free system [5]. In this study, different systems to produce gold nanostars were studied in terms of biocompatibility, stability and further surface modification for biomedical applications such as photothermal therapy or SERS detection. For the further step, silver coating on the gold nanostars synthesized using silver ions as a growth control factor was studied to tune the Plasmon resonance band and to enhance the SERS signals.
Figure caption: TEM image and UV-Vis spectrum of the gold nanostars synthesized by silver ion assisted method.
Acknowledgements: This work has been funded by the ERC through Advanced Grant Plasmaquo.
[1] Xie, J.; Lee, J. Y.; Wang, D. I. C., Chem. Mater 2007, 19, 2823-2830 [2] Moukarzel, W.; Fitremann, J.; Marty, J. D., Nanoscale, 2011, 3, 3285-3290 [3] Kumar, P. S.; Pastoriza-Santos, I.; Rodoríguez-Gonzáles, B.; García de Abajo, F. J.; Liz-Marzán, L.,
Nanotechnol, 2008, 19, 015606 [4] Pallavicini, P.; Chrico, G.; Collini, M.; Dacarro, G.; Dona, A.; D´Alfonso, L.; Falqui, A.; Diaz-
Ferrnandez, Y.; Freddi, S.; Garofalo, B.; Genovese, A.; Sironi, L.; Taglietti, A., Chem. Comm., 2011, 47, 1315-1317
[5] Yuan, H.; Khoury, C. G.; Hwang, H.; Wilson, C. M.; Grant, G. A.; Vo-Dinh, T., Nanotechnol., 2012, 23, 075102
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P18 A simple method to prepare sorbents based on magnetite coated with siliceous
hybrid shells for the removal of non-essential metal ions from waters Daniela S. Tavares1,*, Ana L. Daniel-da-Silva2, Cláudia B. Lopes1, Nuno J. O. Silva2, Vítor S.
Amaral2, João Rocha2, Eduarda Pereira1, Tito Trindade2
1Department of Chemistry-CESAM, University of Aveiro, 3810-193 Aveiro, Portugal 2Department of Chemistry and Physics-CICECO, University of Aveiro, 3810-193 Aveiro, Portugal
The pollution arising from the presence of metals in waste and surface waters presents a severe problem due to the scarcity of drinkable water, and even at low concentrations, mercury and other non-essential metal ions have become a serious environmental problem due to their toxicity, persistent character in the environment and bio-accumulation and bio-amplification along the food chain. Consequently, in the last decades, finding an effective solution to this problem has required the attention of the scientific community [1]. Advances in nanoscale science and engineering are providing opportunities to develop more cost effective and environmentally acceptable water purification processes [2].
This communication presents a new class of sorbents for water purification, based on surface modified magnetite particles with amorphous silica shells incorporating thiolate moieties. A common method to prepare these materials involves several synthesis steps namely the insertion of carbon disulfide in aminic groups in order to functionalize the silica surfaces with dithiocarbamate groups [3]. In this study we demonstrate that the surface of magnetite particles may be chemically modified via a one-step hydrolytic co-condensation process using tetraethoxysilane (TEOS) and a siloxydithiocarbamate (SiDTC) precursor in alkaline medium. This functionalization strategy was applied both to amorphous silica (SiO2) and magnetic (Fe3O4/SiO2) samples aiming at their use as metal-ion sorbents using magnetic separation. Therefore the materials were characterized for their surface characteristics and magnetic behaviour prior their application in water treatment experiments.
The new sorbents were tested for the removal of several metal ions, namely Hg(II), Pb(II), Cd(II), Ag(I), Au(II) and Cu(II) from spiked water. For the particular case of Hg(II), which is considered one of the most hazardous elements, the new sorbents exhibited high sorption affinity that was interpreted in terms of an extensive chemisorption of the cations by dithiocarbamate groups grafted at the siliceous domains. In less than 8 hours, only 2.5 mg of material per litre of an Hg(II) solution with an initial concentration of 50 �g L-1, decreased the metal ion concentration to values lower than the guideline values for drinking water. Moreover, further studies have shown that highly complex matrices, such as natural seawater and natural river water, did not affect the removal capacity of the functionalized magnetic particles.
Acknowledgements: The authors thank Fundação para a Ciência e Tecnologia (PTDC/CTM-NAN/120668/2010, Pest-C/CTM/LA0011/2011, Pest-C/MAR/LA0017/2011), FSE and POPH for funding.
[1] Borai, E. H.; El-Sofany, E. A.; T. N. Morcos, T. N., Adsorption 2007, 13, 95-104. [2] Savage N.; Diallo, M. S., J. Nanopart. Res. 2005, 7, 331-342. [3] Girginova, P. I.; Daniel-da-Silva, A. L.; Lopes, C. B.; Figueira, P.; Otero, M.; Amaral, V. S.; Pereira,
E.; Trindade, T., J. Colloid Interface Sci. 2010, 345, 234–240.
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P19 Anisotropic Gold/PLGA Nanohybrids for Cancer Therapy and Imaging
A. Topete1,*, A. Cambón1, E. Vilar1, M. Alatorre-Meda1, S. Barbosa1, S. Carregal-Romero2, W. Parak2 P. Taboada1, V. Mosquera1
1Colloids and Polymers Physics Group, Physics Faculty, Universidad de Santiago de Compostela, 15782-Santiago de Compostela, Spain.
2Biophotonik Group, Fachbereich Physisk, Phillips-Universität, D-35037, Marburg, Germany *[email protected]
The application of nanomaterials in drug delivery, imaging and therapy is an emerging topic that has captured the interest of researchers from different disciplines, such as physics, chemistry, biology and medicine [1]. This new field, known as nanomedicine, is a promising discipline to achieve better results in different disease therapies and, in particular, in cancer therapeutics, facilitating the translation from long and aggresive treatments to more effective and safer treatments for patients. At this respect, the synthesis of nanoparticles (NPs) of noble metals and polymers based on self-assembly together with top-down approaches have been employed to obtain multifunctional systems capable to simultaneously combine two or more therapies and imaging strategies in one single nanoconstruct [2]. In this work, we present the synthesis, characterization and in vitro evaluation of an hybrid nanoplatform consisting of a poly (D,L-lactide-co-glycolide) (PLGA) core and a gold nanoshell. PLGA NPs produced by the emulsion-evaporation technique were co-loaded with the anticancer drug doxorubicine (DOXO) and iron oxide magnetic NPS for magnetic resonance imaging and targeting. An anisotropic spiky gold nanoshell was built over the PLGA cores to provide our nanosystem with NIR photothermal therapeutic, optical imaging abilities [3], and photo-activable release of DOXO cargo. The nanoshells were, in some case, additionally functionalized with targeting ligands (folic acid or Herceptin) to ensure a receptor-mediated cell internalization process, or with a highly stable conjugate of human serum albumin/indocyanine green to also use the nanoplatform as a potential photosensitizer for photodynamic therapy (PDT) and NIR fluorescence imaging. Here, we present the synthetic and bio-conjugation routes, structural and physi-cochemical characteri-zation and in vitro evaluation of the nanoconstruct.
Figure caption: a) TEM image of gold/PLGA nanoshell; b) Confocal image of HeLa cells with
internalized nanoshells (green). c) Confocal images of laser triggered Dox release inside HeLa cells.
Acknowledgements: Authors thank Ministerio de Ciencia y Competitividad and Xunta de Galicia for financial support. A. Topete thanks CONACYT, México, for his scholarship.
[1] Shi, D. Adv. Funct. Mater 2009, 19, 3356–3373. [2] Ryu, J. H.; Koo, H.; Sun, I.C.; Yuk, S. H.; Choi, K.; Kim, K.; Kwon, I. C. Adv. Drug Deliv. 2012, 64,
1447-1458. [3] Gobin, A. M.; Lee, M. H.; Halas, N. J.; James, W. D.; Drezek, R. A.; West, J. L. Nano Letters 2007,
7, 1929-1934.
a) b) c)
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P20 Thermal effects in loaded lipid nanoparticles dispersion and hybrid membranes
M. I. Vazquez1, J. Hierrezuelo2, J. M. López-Romero2, J. Benavente1,*
1Dpto. Física Aplicada I. Facultad Ciencias. Universidad de Málaga, E-29071 Málaga, Spain 2Dept. de Química Orgánica. Facultad Ciencias. Universidad de Málaga, E-29071 Málaga, Spain
Encapsulation technologies are nowadays commonly used in pharmaceutical, medical and cosmetic industries for the development of controlled-release delivery systems 1 . Many therapeutically active molecules need to be encapsulated in a drug carrying system to prevent the loaded drug from degradation but also to ensure their effective delivery in the biological media. Solid lipid nanoparticles (SLNs) represent a class of particulate carriers for bioactive organic molecules with advantages over other carrier systems which include good-to-high loading capacity, low production costs and the possibility of large-scale industrial production. LNPs can be prepared from natural sources by using biocompatible components, and their properties can be tuned by controlling the nanoparticle shape, size and state of aggregation [2]. LNPs prepared using biocompatible components and with tuneable properties are of significant interest, although their use is still limited due to stability problems during contact with biological fluids, storage or administration. To overcome these limitations, functionalized LNPs can be included in biocompatible supports, which offer an attractive route for the control release of the active agents and their use as patches [3].
This paper shows temperature effects on water-dispersions of lecithin-triestearine nanoparticles loaded with the sunscreen agent 2’,4’-dihydroxybenzophenone (DHB) and the hybrid membrane obtained after their inclusions in a cellulosic (RC) support (DHBLNPs and DHBLNPs/RC samples). Figure shows SEM and brilliant field microscope pictures for the DHBLNPs (a) and the DHBLNPs-RC hybrid membrane. Our results show an increase in the conductivity of the DHBLNPs with temperature independently of the nanoparticles percentage in the solution, but a significant reduction in the case of the DHBLNPs/RC membrane, this latter obtained from IS technique with dry samples. NaCl diffusional permeability (c = 0.1 M) across the hybrid DHBLNPs/RC membrane for 20 �t(ºC)� 80 ºC follows the same tendency than that found for the RC-support but values reduction around 25 %. These results indicate the stability of the hybrid membrane for the range of temperature studied as well as under osmotic pressure and aqueous environments.
Figure caption: (a) DHBLNPs SEM micrograph; brilliant field micrograph of DHBLNPs/RC membrane
Acknowledgements: CICYT (projects CTD/2011-27770 and CTQ/2010-17633) or financial support.
[1] Goodsell, D.S. Bionanotechnology; Wiley–Liss: New Jersey, 2004. [2] Muchow, M.; Maincent, P.; Müller, R.H. Drug Dev. Ind. Pharm., 2008, 34, 1394–1405. [3] Vázquez M.I., Peláez L., Benavente J., López-Romero J.M., Rico R., Hierrezuelo J, Guillén E.,
López-Ramírez, M.R. J. Pharmac. Sci. 2011, 100, 4815-4822.
(b)
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P21 Control of the aggregation of primary nanocrystals during particle growth: from
smooth to rough magnetite particles F. Vereda1, M. P. Morales2, B. Rodríguez-González3,4, J. de Vicente1 and
R. Hidalgo-Álvarez1,* 1Biocolloid and Fluid Physics Group, Applied Physics Department, Faculty of Science, University of
Granada, E-18071 Granada, Spain 2Materials Science Institute of Madrid, CSIC, Sor Juana Inés de la Cruz 3, 28049 Madrid, Spain
3International Iberian Nanotechnology Laboratory, Braga 4715, Portugal 4CACTI, Vigo University, E-36310 Vigo, Spain
We studied the morphology, internal structure and magnetic properties of magnetite microparticles prepared by partial oxidation of ferrous hydroxide with KNO3 at different excesses of Fe2+ ([Fe2+]Exc) We observed an obvious evolution of the surface morphology and of the internal structure of the particles with [Fe2+]Exc: particles were relatively smooth polyhedral single crystals at small [Fe2+]Exc, and became polycrystalline and developed a surface roughness as [Fe2+]Exc increased. The different internal structures (and thus the different surface morphologies) can be explained in terms of different mechanisms of growth. Polyhedral particles are formed by direct crystal growth of the primary nanocrystals that appear after the initial nucleation. The formation of the rough polycrystalline microparticles involves the aggregation of these primary nanocrystals, followed by their direct crystal growth in the radial direction [1] (see diagram below). The growth mechanisms are qualitatively in agreement with the evolution of electrostatic repulsion between the growing magnetite particles, as inferred from the progress of the system’s pH.
Figure caption: Schematic diagram (not to scale) of the different mechanisms that control particle growth at increasing [Fe2+]Exc, resulting in the different surface morphologies shown in the micrographs. “Direct
CG” stands for “direct crystal growth”. Scale bars correspond to 1 m.
Acknowledgements: F. Vereda is grateful to the ‘Programa de reincorporación de doctores de la Universidad de Granada’. This work was supported by MICINN MAT 2010-15101 and MAT2011-23641 projects (Spain), the European Regional Development Fund (ERDF) and the Junta de Andalucía P10-FQM-5977, P10-RNM-6630 and P11-FQM-7074 projects (Spain). J. de Vicente and R. Hidalgo-Alvarez thank the financial support received from CEI-Biotic 20F12/16.
[1] Rodríguez-González, B.; Vereda, F.; de Vicente, J.; Hidalgo-Álvarez, R. J. Phys. Chem. C 2013, 117, 5367-5406.
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P22 Synthesis of ZnO/Ag hybrid nanomaterials and study of their electrical
properties (Poster, Topic: Nanoparticles: organic, inorganic and hybrids) German Vidal-Lopez1,*, Kelly Pemartin2, Conxita Solans2, Alfredo Morales-Sanchez1,
Margarita Sanchez-Dominguez1 1Centro de Investigación en Materiales Avanzados (CIMAV S.C.), GENES-Group of Embedded
Nanomaterials for Energy Scavenging, Apodaca, 66600, MEXICO. 2Instituto de Química Avanzada de Cataluña (IQAC-CSIC), and CIBER en Bioingeniería, Biomateriales
y Nanomedicina (CIBER-BBN), Barcelona, 08034, SPAIN. *[email protected]
In this work the synthesis of hybrid ZnO/Ag nanomaterials by the microemulsion reaction method has been investigated. The aim of the research is to synthesize different ZnO morphologies and NPs size by varying the conditions of the method and by adding silver on ZnO in order modulate the electrical properties. Two strategies were used for the preparation of the hybrid ZnO/Ag nanomaterial. The first strategy consists of two steps, first a reaction is carried out by using an oil-in-water (O/W) microemulsion containing an organometallic precursor of Zn in the oil phase and adding a precipitating agent (base) in order to obtain ZnO nanoparticles. The second step consists in the synthesis of Ag nanoparticles by the water-in-oil (W/O) microemulsion method, followed by addition of ZnO nanoparticles synthetized previously by the oil-in-water microemulsion method. The second, one-pot strategy consists in the synthesis of Ag nanoparticles in an W/O microemulsion, and then a Zn precursor is added to the aqueous phase followed by precipitation of ZnO nanoparticles using a second microemulsion containing a base in the aqueous phase. In general for the different materials synthesized, the X-ray diffraction (XRD) analysis corresponds with hexagonal crystalline structure for ZnO and a cubic crystalline structure for Ag. The SEM micrographs have demonstrated that the structure obtained depends on the base used for precipitation. Different ZnO self-assembled nanostructures were obtained: raspberry[1], flowers[1] and bow-like. These self-assemblies are formed by individual nanoparticles of ZnO. On the other hand, the XRD patterns have demonstrated good chemical compatibility between the two materials at a concentration of 5% of Ag on ZnO, since no chemical change was observed upon their combination; however in order to obtain this result, the sequence in the reaction method and the reaction conditions were critical. For the electric measurements a device was fabricated. The hybrid nanomaterial was incorporated into a polymeric matrix. Then a layer of the polymeric matrix was deposited onto an ITO-coated PET substrate by spin-coating followed by deposition of the metallic contacts. It was demonstrated that the electrical properties of the hybrid nanomaterial can be modulated as a function of the method used to synthesize the hybrid Ag/ZnO nanomaterial with different structures.
Acknowledgements: We acknowledge CONACYT for the financial support (CB project No. 166649) as well as Josué A. Aguilar, Cesar Leyva and Nayeli Pineda (CIMAV, S.C.) for their technical assistance.
[1] Permartin, K.; Solans, C.; Vidal, G.; Sanchez, M., Chem. Lett. 2012, 41, 1032-1034.
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P23 Design of a dual nanostructured lipid carriers formulation based on
physicochemical, rheological and mechanical properties Carla Vitorino1, Luís Alves2, Filipe E. Antunes2, João J. Sousa1, Alberto A. C. C. Pais2,*
1Centro de Estudos Farmacêuticos (CEF), Faculty of Pharmacy, University of Coimbra, Portugal 2Department of Chemistry, University of Coimbra, Portugal
The synergy between nanostructured lipid carriers (NLC) and chemical penetration enhancers have been investigated as a promising strategy to effectively deliver drugs through the skin. In the present work, focus is given on the study of the interaction of limonene, ethanol and Carbopol Ultrez®10NF as gelling agent with a co-encapsulating NLC dispersion, containing both olanzapine and simvastatin. The analysis is based on the rheological, mechanical and physicochemical properties.
Only a small increase in the mean NLC particle size was observed when the temperature was raised up to 50ºC. Ethanol generally tended to increase NLC mean particle size, while the more hydrophobic limonene did not impact on this parameter. A swelling mechanism is probably responsible for the alteration with the former, hypothesis corroborated by the observed increase in the steady viscosity. The inclusion of the gelling agent resulted in a further increase in size. This can be attributed to carbomer bridging nanoparticles and causing some degree of particle aggregation. Rheological measurements indicated that the viscosity of the neat carbopol hydrogel was significantly reduced by the addition of enhancers and, to a higher extent, by the further inclusion of the NLC. A change in the bulk solution properties due to a more apolar medium can be pointed out as explanation. A hydrophobic polymer/nanoparticle interaction coupled with surfactant/polymer H-bonding provides the rationale for the NLC effect. Texture analysis, comprising compressibility, hardness, adhesiveness, elasticity and cohesiveness measurements, provided a complementary characterization, relevant for product performance and corroborated the trends found in the rheological measurements. The inclusion of enhancers and polymer gelling agent largely contributed to the physicochemical stability of the NLC formulation, as revealed by the low transmission profiles and more negative zeta potential values.
Figure caption: Rheological, mechanical and stability analysis of an optimized NLC formulation.
Acknowledgements: CSV acknowledges financial support through grant SFRH/BD/41536/2007 from FCT (Fundação para a Ciência e Tecnologia, Portugal). We acknowledge Dr. Pedro Prazeres from GmBH (Dias de Sousa) for the availability of LUMiFuge centrifuge.
[1] Vitorino, C.; Almeida, J.; Gonçalves, L. M.; Almeida, A. J.; Sousa, J. J.; Pais, A. A. C. C., J. Controlled Release 2013, 167, 301.
POLYMERS, POLYELECTROLYTES, SURFACTANTS AND GELS 168
P24 Thermodynamic study of the interaction between 5,10,15,20-Tetrakis-(N-methyl-
4-pyridyl)porphyrin tetraiodine and sodium dodecyl sulfate: a conductometric study
C. M. R. Almeida, R. F. P. Pereira, Bruno F. O. Nascimento, M. Pineiro and A. J. M. Valente*
Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal *[email protected]
Porphyrin defines an enormous class of compounds with diverse applications. The photochemical and catalytic properties of the tetrapyrrolic macrocycle, which form the porphyrin core, could be modulated trough the insertion of different substituents at the periphery or through the coordination with several metals, making them appropriate for such different applications as photodynamic therapy of cancer or photovoltaic devices.[1] 5,10,15,20-Tetrakis-(N-methyl-4-pyridyl)porphyrin tetraiodine (1) is a water soluble porphyrin, highly symmetrical , with four coordination sites that compared with di- and tri-cationic ligands, are relatively rarely used as molecular building blocks [2].
In this communication, we report the effect of 5,10,15,20-Tetrakis-(N-methyl-4-
pyridyl)porphyrin tetraiodine on the micellization properties of sodium dodecyl sulfate. It has been found that interaction between SDS and (1) occurs at concentration considerably below the surfactant cmc. The aggregates have a stoichiometry similar to that expected by charge neutralization. On the contrary to results obtained for interactions between trivalent metal ions and SDS [3], these aggregates do not redissolve in the presence of an excess of SDS. The effect of (1) on the thermodynamic of SDS micellization will also be discussed.
[1] Chou, J.-H.; Nalwa, H. S.; Kosal, M. E.; Rakow, N. A.; Suslick, K. S. in The porphyrin handbook, Vol. 6 (Eds.: K. M. Kadish, K. M. Smith, R. Guilard), Academic Press, San Diego, 2000.
[2] DeVries, D. L.; Choe, W. J. Chem. Crystallogr. 2009, 39, 229-240. [3] Pereira, R. F. P.; Tapia, M. J.; Valente, A. J. M.; Evans, R. C.; Burrows, H. D.; Carvalho, R. A. J.
Colloid Interface Sci. 2011, 354, 670-676
N
NH N
HNN
N
N
N 1
POLYMERS, POLYELECTROLYTES, SURFACTANTS AND GELS 169
P25 Rheological studies of unmodified cellulose solutions based on new
promising alkali solvent systems Luís Alves1, Carolina Costa1, Filipe Antunes1,*, Bruno Medronho2 and Björn Lindman1
1Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal 2Faculty of Sciences and Technology, Institute for Biotechnology and Bioengineering, Centre of
Genomics and Biotechnology (IBB/CGB), University of Algarve, Campus de Gambelas, Ed. 8, 8005-139 Faro, Portugal *[email protected]
Cellulose has many industrial applications and is the most used biopolymer in the world. The estimated amount of cellulose and derivatives used each year, exceed 75 million tons[1]. Many important cellulose applications involve, at some stage, dissolution and, for different reasons, this task is normally complicated. Traditional dissolution methods have important limitations especially allied to environmental and human health issues and thus there is a growing need to replace these severe processes.
The development of cheaper, environmentally and human friendly alternatives, without toxic compounds, to the solvents used nowadays is thus of great interest in the industrial circle.
In this work, we have develop new promising alkali based solvents, showing good dissolution ability of cellulose with reasonably high molecular weight. The phase behavior and rheological properties were studied as a function of temperature, composition, concentration and it was found that the viscosity of solutions increases both with cellulose content and temperature decrease. Gelation, usually observed in cellulose solutions, represents a problem in industrial applications making the spinning process of the fibers very difficult. Therefore, we have also evaluated the time dependent gelation phenomenon. The solutions were quite stable and no gelation was found using these alkali based solvent systems. These cellulose solutions are a very promissory for fiber spinning. Films could be precipitated from cellulose solutions using simple coagulations systems such as water, ethanol or acidic solutions.
[1] Kirk-Othmer, Kirk-Othmer Encyclopedia of Chemical Technology. 5th Edition ed.; John Wiley & Sons, Inc.: 2004; Vol. 5.
POLYMERS, POLYELECTROLYTES, SURFACTANTS AND GELS 170
P26 Nanostructuring conjugated polyelectrolytes in tetraethylene glycol
monododecyl ether/water liquid crystals Hugh D. Burrows1, *, Matti Knaapila2, Sofia M. Fonseca1, Beverly Stewart1, Mika Torkkeli3,
Jan Perlich4, Swapna Pradhan5 and Ullrich Scherf5
1Departamento de Química, Universidade de Coimbra, Portugal. 2Physics Department, Institute for Energy Technology, NO-2027 Kjeller, Norway.
3Department of Physics, FI-00014 University of Helsinki, Finland. 4 DESY Photon Science, D-22607 Hamburg, Germany
5 Macromolecular Chemistry Group, Bergische Universität, D-42119 Wuppertal, Germany *[email protected]
Conjugated polyelectrolytes (CPEs) are an important group of materials, with applications ranging from light emitting devices, photovoltaic cells to chemical or biological sensors. Their aqueous solubility favours processing from solution using methodologies such as ink-jet printing, and may also facilitate self-assembly. Fluorene based systems are excellent candidates for many of these applications because of their blue emission, high fluorescence quantum yield and possibility of modification to make them good charge carriers [1]. Although they tend to cluster in water, we have shown that it is possible to obtain homogeneous solutions having isolated conjugated polymer chains by using non-ionic oxyethylene based surfactants, CmEn [2]. These form cylindrical micelles, which grow upon increasing surfactant concentration to give long, wormlike structures. In addition to micellar solutions, non-ionic surfactants form a wide variety of liquid crystalline phases with water [3]. We report a combined fluorescence spectroscopy and small angle and grazing incidence X-ray scattering study on the anionic poly[9,9-bis(4-sulfonylbutoxyphenyl)fluorene-2,7-diyl-2,2'-bithophene] (PBS-PF2T) in aqueous 25% tetraethylene glycol monododecyl ether (C12E4) in bulk and thin films. These indicate that PBS-PF2T is present as isolated chains and that this mixture follows similar phase behaviour to the pure surfactant, including a micellar phase below about 20 oC, a lamellar phase in between about 20 and 70 oC and a proposed coexistence of water and liquid surfactant solution above 70 oC. Molecular dynamics simulations suggest the CPE is localised in the surfactant head group region, with the ionic chains pointing into the water domains.
Structure of PBS-PF2T
[1] Scherf, U.; Neher, D., Eds., Polyfluorenes, Adv. Polym. Sci. 2008, vol.212. [2] Burrows, H.D., Knaapila, M.; Fonseca, S.M., Costa, T., Aggregation Properties of Conjugated
Polyelectrolytes. In “Conjugated Polyelectrolytes. Fundamentals and Applications in Emerging Technologies”, ed. B. Liu, G. C. Bazan, Wiley-VCH, Weinheim, 2013; pp 127-167.
[3] Holmberg, K., Jönsson, B., Kronberg, B., Lindman, B. Surfactants and Polymers in Aqueous Solution, Wiley, Chichester, 2nd Edn., 2003.
PBS-PF2T
n
SS
OO
SO3NaNaO3S
POLYMERS, POLYELECTROLYTES, SURFACTANTS AND GELS 171
P27 A novel approach to the development of unmodified cellulose solvents
Carolina Costa1, Luís Alves1, Filipe Antunes1,*, Bruno Medronho2, M. Graça Miguel1 and Björn Lindman1
1Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal 2Faculty of Sciences and Technology, Institute for Biotechnology and Bioengineering, Centre of
Genomics and Biotechnology (IBB/CGB), University of Algarve, Campus de Gambelas, Ed. 8, 8005-139 Faro, Portugal *[email protected]
Cellulose is the most abundant natural polymer in the world and has numerous applications. Some important industrial applications involve a dissolution step but this is normally challenging since cellulose is difficult to dissolve. However, a large number of solvents have been developed in the last years but, in general, most of them are limited to lab scale applications due to, for instance, cost and environmental issues. Thus, there is a need to find “greener” alternatives. It is clear that for the industry sector, the development of cheaper and environmentally friendly alternatives to the solvents used nowadays is thus of great interest.
Promising alkali based solvents has been developed in this work. Good results regarding cellulose dissolution with reasonably high molecular weight were obtained. Additionally, polarized light microscopy and scanning electron microscopy were used to infer about the solvent quality. It was found that during cellulose regeneration (i.e. coagulation in “anti-solvent” such as an acidic aqueous medium) a crystal rearrangement seems to occur. The amount of crystals appeared to increase after regeneration. Finally, transparent films could be precipitated from cellulose solutions using simple coagulations systems such as water and ethanol.
POLYMERS, POLYELECTROLYTES, SURFACTANTS AND GELS 172
P28 Water-Borne Pressure Sensitive Adhesives based on Renewable Protic Ionic
Liquids Ana M. Fernandes1,2,*, Monica Moreno2, Ali Adboudzadeh2, Raquel Gracia2, Maria J. Barandiaran2, David Mecerreyes2,3
1Polytechnic Institute of Bragança, Portugal. 2POLYMAT, University of the Basque Country (UPV/EHU),
Joxe Mari Korta Center, Avda. Tolosa 72, 20018 Donostia-San Sebastian, Spain. 3Ikerbasque, Basque Foundation for Science, E-48011 Bilbao, Spain.
Nowadays, several arguments account for the great potential of renewables resources as an alternative for the production of polymeric materials [1]. The high price and future lack of fossil fuels are creating doubts about the sustainability of the current polymer industry. Carboxylic acids are widespread in nature and important raw materials for the synthesis of a number of industrial polymers. For these reasons, there is a growing interest in the use of natural products for the development of polymers that match or even improve the performance of the current oil-based polymeric materials [2].
In this work, we extended our initial research in the development of protic polymeric ionic liquids [2-3], which incorporate renewable carboxylic acids. The application of this chemistry, to develop green odorless polymer latexes, was investigated based on new latexes obtained by emulsion polymerization of dimethylaminoethyl methacrylate and renewable dicarboxlylic acids. The synthetic results and the adhesion test carried out will be presented.
Figure caption: Incorporation of carboxylic dimer acids into ionic polymers.
Acknowledgements: The financial support of Basque Government and MINECO through projects MAT2010-16171 is acknowledged.
[1] R. Vendamme, K. Olaerts, M. Gomes, M. Degens, T. Shigematsu, W. Eevers, Biomacromolecules, 2012, 13, 6, 1933-44.
[2] M. Moreno, M.A. Aboudzadeh, M.J. Barandiaran, D. Mecerreyes, J. Polym. Sci. Part A Polym. Chem. 2012, 50, 6, 1049-1053.
[3] D. Mecerreyes, Progr. Polym. Sci., 2011, 5, 7.1629-1648.
POLYMERS, POLYELECTROLYTES, SURFACTANTS AND GELS 173
P29 Biomimetic Triblock Copolymer Membranes:
From aqueous solutions to solid supports A. González-Pérez1, V. Castelletto2, I. Hamley2, A. Topete3, E. Villar-Alvarez3, N. González3,
A. Cambón3, S. Barbosa3, P. Taboada3, V. Mosquera3 1Membrane Biophysics Group, Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100
Copenhagen Ø / Denmark. 2School of Chemistry, Food Science and Pharmacy, University of Reading, Whiteknights, Reading RG6
6AD, UK 3Department of Condensed Matter Physics, Faculty of Physics, 15782 Campus Sur, University of
Santiago de Compostela, Santiago de Compostela, Spain
In the present work, the preparation of biomimetic triblock copolymer membranes formed by a triblock copolymer of poly(dimethylsiloxane) (PDMS) and poly(2-methyloxazoline) (PMOXA), PMOXA7-PDMS60-PMOXA7 (type ABA, where the subscripts denote the block length) in aqueous solution and their deposition into solid supports is studied. The self-assembly structures of the ABA in aqueous solution was investigated by using optical microscopy, dynamic light scattering, electron microscopy (EM) and SAXS, as was found to be concentration-dependent, this opens up additional possibilities to use organic solvent-free membranes as a support for membrane protein incorporation. In particular, spherical and tubular polymersomes were found to coexist at the highest concentrations investigated, the relative population of which depends on the polymer concentration. The mechanism of deposition onto solid supports (mica and glass) was elucidated by using atomic force microscopy (AFM). The deposition results in the formation of a uniform defect-free membrane at suitable polymer concentrations. The interaction between polymeric membranes and solid substrates become a key step in the development of new solid-supported membranes containing embedded membrane proteins.
POLYMERS, POLYELECTROLYTES, SURFACTANTS AND GELS 174
P30 Spectroscopic study of the interaction of Hecameg with Bovine Serum Albumin
and its effect on the protein conformation J. M. Hierrezuelo1, B. Nieto-Ortega2 and C. Carnero-Ruiz1,*
1Department of Applied Physics II, University of Málaga, 29071�Málaga. Spain. 2Department of Physical Chemistry, University of Málaga 29071�Málaga. Spain.
Ionic surfactants interact more effectively with proteins than nonionic surfactants, promoting often unfolding and, consequently, protein structure alterations. However, there are applications that require preservation of protein functionality and the use of nonionic surfactants is preferred in these cases. Among these applications, the isolation and purification of membrane proteins and the stability of protein-based pharmaceutical formulations, occupy a prominent place. In order to assess the potential use of the nonionic surfactant 6-O-(N-Heptylcarbamoyl)-methyl-�-D-glucopyranoside (Hecameg), belonging to the alkyl polyglycosides family, as a stabilizing agent of proteins, we have studied its interaction with the protein Bovine Serum Albumin (BSA), at pH 7.4 and 25 ºC, using spectroscopic techniques such as steady-state and time-resolved fluorescence and circular dichroism (CD). The changes in the intrinsic fluorescence spectra of BSA induced by the surfactant addition indicate a weak interaction between surfactant and protein. These data allows us to obtain the binding curve (the insert of Figure), estimated from the fraction of protein occupied by surfactant, �, which suggests that Hecameg binds in a sequential manner to protein. At low surfactant concentration, � slightly increases with the surfactant concentration, indicating an initial non-cooperative binding process where the hydrophobic interactions are probably predominant. From a certain surfactant concentration, it is seen an abrupt increase of � with the surfactant concentration, until reaching a plateau. This second region clearly reflects a cooperative binding scenario, which finally leads to the saturation binding region. Similar conclusions were extracted from time-resolved fluorescence studies, which also reflect a stepwise mechanism, whereby the surfactant first occupies the hydrophobic sites of the protein inner cavity and then, through a cooperative mechanism, condensates onto the surface hydrophobic sites of the protein. Finally, CD studies indicate that the secondary structure of BSA is not appreciably perturbed by the surfactant binding over the concentration range studied.
Figure caption: Intrinsic fluorescence of BSA as a function of the total surfactant concentration in aqueous buffer solutions of pH 7.4 and 25 ºC. Inset: binding curve, showing the fraction of a protein
molecule bound by surfactant, �, as a function log of the total surfactant concentration. Acknowledgements: This work has been financially supported by the “Consejería de Innovación, Ciencia y Empresa de la Junta de Andalucía” (Project P07-FQM-02762).
0 5 10 15 20 25 30 35 403.5x103
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[Hecameg] (mM)
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.)
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POLYMERS, POLYELECTROLYTES, SURFACTANTS AND GELS 175
P31 Novel Structural Changes During Temperature-Induced Self-Assembling and
Gelation in Aqueous solutions of the Copolymer PLGA1170-PEGn-PLGA1170 Neda Khorshid1, Kenneth Knudsen2, Sverre Arne Sande3, and Bo Nyström1,*
1Department of Chemistry, University of Oslo, Oslo, Norway. 2Department of Physics, Institute for Energy Technology, Kjeller, Norway.
3Department of Pharmaceutics, School of Pharmacy, University of Oslo
It is well established that certain polymers undergo conformational changes in response to changes in temperature, pH, magnetic field, electrical field, or the wavelength of light. In one type of stimuli-responsive polymer, thermogel polymers, the polymer aqueous solution undergoes sol-to-gel transition as the temperature increases. Drugs or cells can be mixed into the polymer aqueous solution when it is in its lower viscosity solution state. After injection of the solution into a target site, heating prompts the formation of a hydrogel depot in situ, which can then act as a drug releasing system or a cell growing matrix. In this presentation, we have employed small-angle neutron scattering (SANS) technique to study temperature-induced structural transitions of water-soluble triblock copolymers of the type [1,2] poly(D,L-lactic acid-co-glycolic acid)1170-block-poly(ethylene glycol)n-poly(D,L-lactic acid-co-glycolic acid)1170 (PLGA1170-b-PEGn-PLGA1170). The length of the PEG spacer assumes two values (n =1000 and n =1500) and this gives rise to fundamental different structural features of the polymer complexes in dilute and semidilute concentration regimes at different temperatures. The length of the PEG spacer has dramatic implications for the structures formed in dilute aqueous solution (1 wt %). For the longest PEG chain (n = 1500), temperature-stable spherical micelles are created. These micelles are probably stabilized due the fact that the PEG chain is long enough to turn back on itself so that both PLGA-ends of one chain can be incorporated into the same micelle. For the PEG block with n = 1000, the micelles cannot be stabilized like that with n =1500, and the equilibrium conformation at low temperature (10 oC) is an elongated micelle (prolate) with the PEG chains extending into solution. At high temperatures, these disk-like particles will easily aggregate and start to sediment at the highest temperature of measurement.
In semidilute solutions (20 wt%) of the copolymer with n=1000, intermicellar interactions with the formation of core-shell structures is observed at 10 oC. At 20 oC, the correlation peak in the SANS scattering curve disappears, because a gel network is formed; at 30 oC rod-like entities are created (cylinder length: 34 nm and radius 6 nm) and at 40 oC, close-packing (hexagonal packing) of micelles to thick “cylinders” (d = 16 nm) occurs (see Figure 1). For the copolymer with n=1500, similar scattering profiles evolve but in this case flower-like micelles can be formed and they are more stable than those formed for n = 1000, and the gel network is formed 40 oC as compared with 20 oC for n=1000. These novel structural features for this type of copolymer in aqueous solution have not been reported previously.
Figure caption: SANS scattering data for a 20 wt% aqueous solution of PLGA1170-b-PEG1000-PLGA1170 at different temperatures and the change from spherical micelles to cylindrical micelles and the formation of gel at 20 oC.
[1] Lee, D. S.et. al. Macromol. Rapid Commun. 2001, 22, 587-592. [2] Chen, S. Int. J. Pharm. 2005, 288, 207–218.
POLYMERS, POLYELECTROLYTES, SURFACTANTS AND GELS 176
P32 Synthesis and mineralization of a polymeric network using the reaction diffusion
method. Enrique Lopez-Cabarcos*, Yousof Ramadan, Jorge Rubio-Retama
Department of Physical-Chemistry II, Faculty of Pharmacy, Complutense University of Madrid, Plaza Ramón y Cajal 2, 28040 Madrid, Spain.
The formation of precipitates in a gel after the meeting of two reaction fronts that diffuse from opposite sides enables to relate scientific fields that are normally separated such as gel structure, dynamics of reaction fronts, crystal growth in gels, nanoparticles synthesis, and biomineralization. Even though this is an old research subject, a new approach to the phenomenon was taken recently when gels started to be used as a model to study biomineralization since many mineralization processes take place in gelling environments [1]. Most of the research in this field was performed using physical gels such as gelatin, agarose, silica, starch, polyvinyl alcohol) hydrogels [2-4], and only a few studies were done with chemical gels [5].
We have selected hydrogels based on methacrylates because they are biocompatible, non toxic, non-immunoreactive and their porosity can be controlled by the amount of cross-linker. We have synthesized and characterized a new copolymer matrix formed by polyethylene glycol methyl ether methacrylate and 2-dimethylamino ethyl methacrylate, crosslinked with N,N�-methylenebisacrylamide. A piece of the swelled gel is inserted in the middle of a plastic tube connected to both sides with silicone tubes that ended each one in a bottle containing an aqueous solution of the corresponding reactant. The reactants are aqueous solutions of CaCl2 (20 mM) and Na2HPO4 (20 mM) and the temperature was around 20 ºC. In Fig.1 we can see a SEM micrograph of the calcium phosphate particles (brushite) formed within the gel. The distribution of particle size is rather homogeneous with dimensions between 2 and 3 microns. The TEM picture of the calcium phosphate microparticle shows that is formed by nanocrystals of brushite (CaHPO4·2H2O). The gel-calcium phosphate composite might have application in dentistry as bone regeneration biomaterial.
Figure caption: SEM pictures of the calcium phosphate microparticles formed with the gel
[1] Hanying, L.; Huolin, L. X.; Muller, D. A.; Lara, A. Science 2009, 326, 1244-1277. [2] Lopez-Cabarcos, E.; Kuo, C. S.; Scala, A.; Bansil, R. Phys. Rev. Lett. 1996, 77, 2834-2837 [3] Sander, C.G.; Leeuwenburgh, C.; Junichiro, J.; Wang, H.;. Yamamoto, M; Jansen, J. A.; Tabata, Y.
Biomacromolecules 2010, 11, 2653–2659 [4] Sohier, J.; Corre, P.; Weiss, P.; Layrolle, P. Acta Biomaterialia 2010, 6, 2932–2939, [5] Yokoi, T.; Kawashita, M.; Kikuta, K.; Ohtsuki, C. Materials Sci. Eng. C 2010, 30, 154–159
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P33 Adsorption of polyelectrolyte-surfactant mixtures of cosmetic interest
Sara Llamas1, Ramón G. Rubio1,*, Francisco Ortega1, Nawel Baghdadli2, Gustavo Luengo2, Colette Cazeneuve2
1Departamento de Química Física I, Facultad de Química, Universidad Complutense, 28040-Madrid,
Spain. 2L’Oréal Research, Aulnay-sous-Bois, France. *[email protected]
The interactions between polymers and surfactants in aqueous solution have attracted a growing interest in colloidal science because of their major role in a wide range of industrial applications, among which cosmetic applications stand out. This mixtures form supramolecular structures that have unusual mechanical, optical and electrical properties that may help to make better formulations in hair-care products.
The interactions between polymers and surfactants of opposite charge are quite strong and can induce complex formation often resulting highly ordered structures [1]. Both electrostatic interactions (between the charged components) and hydrophobic interactions (e.g. between the polymer backbone and the alkyl chains of the surfactant) are important in driving the self-assembly of the molecules to form ordered structures. As a consequence, these systems show two characteristic points as the surfactant concentration is increased: the critical aggregation concentration (c.a.c.) and the critical micelle concentration (c.m.c.) [2].
The applications under discussion involve the adsorption and deposition of complexes onto a negatively charged surface (model surfaces that simulate that of the hair fibers). In this work, mixtures of cationic polyelectrolytes with anionic and zwitterionic surfactants has been studied at the air-liquid and liquid-solid interfaces. Formation and adsorption of complex have been studied by surface tension, � potential, dynamic light scattering, quartz-crystal microbalance, and ellipsometry measurements. The results show that there is a strong synergistic effect between the polyelectrolyte and the surfactant in decreasing the air/liquid surface tension, leading to an important decrease of the c.m.c. The adsorption at the solid/liquid interface has shown that the addition of the surfactant improves pure polyelectrolyte’s adsorption properties, and the ability of the polymer layer to capture water. The last characteristic is important for improving the tribological properties of the hair fibers, and therefore the performance of the conditioner product.
Acknowledgements: This work has been supported by L’Oréal Research.
[1] K. Kogej, Adv. Colloid Interface Sci. 2010, 158, 68-83. [2] C. D. Bain, P. M. Claesson, D, Langevin, R. Meszaros, T. Nylander, C. Stubenrauch, S.Titmuss, R.
Von Klitzing, Adv. Colloid Interface Sci. 2010, 155, 32-49.
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P34 Molecular dynamics simulations of surfactant micelles Victoria I. Martín*, Luis Javier Álvarez1 and María Luisa Moyá
Department of Physical Chemistry, University of Seville, C/Profesor García González 1, 41012 Sevilla. 1Laboratorio de Simulación, Instituto de Matemáticas, Unidad Cuernavaca, Universidad Nacional
Autónoma de México. A. P. 273-3. Admon. 3, 62251 Cuernavaca, Morelos, México *[email protected]
In a previous work the two single-chain surfactants N-benzyl-N,N-dimethyl-N-(1-dodecyl)ammonium bromide (PH12) and N-cyclohexylmethyl- N,N-dimethyl-N-(1-dodecyl)ammonium bromide (CH12) were prepared and characterized [1]. The aggregation numbers estimated for these two surfactants seemed too low when compared to those of related single-chain surfactants. This result was investigated with the help of 1H NMR ROESY measurements (see Figure), which point out that the phenyl and cyclohexyl rings present in the head groups of the surfactants are bent towards the micellar interior in order to avoid contact with water. With the goal of further investigating this point, molecular dynamics, MD, simulations were carried out. The effective charge values were determined through periodic Hartree–Fock calculations. Water is treated using a single point charge model (SPC), consisting of a tetrahedral arrangement with an OH distance of 0.1 nm, with point charges on the oxygen and hydrogen positions of -0.82 e and +0.41 e respectively. We also used a Lennard-Jones interaction potential between oxygen. All calculations were carried out with the Gromacs package using the implemented force field that includes Lennard-Jones interactions plus coulombic ones when necessary. Molecular mechanics energy minimizations were carried out in order to obtain reasonable initial configurations for the molecular dynamics simulations. The MD runs were performed at constant temperature in the NVT ensemble. Each MD schedule proceeded as follows: first, a solvent relaxation run of 500 ps; second, a temperature controlled run with Berendsen’s thermostat at 300 K for 5 ns and third, a statistics and accumulation production run of another 5 ns. Results indicate that the rings are bent toward the micellar interior in agreement with the observations.
Figure caption: Partial ROESY spectrum of an aqueous micellar solution of [PH12]=0.01 M. T=303 K.
Acknowledgments. This work was financed by the DGCYT (grant CTQ2009-07478), the FEDER funds and Consejería de Innovación, Ciencia y Empresa de la Junta de Andalucía (FQM-274 and P07-FQM-03056).
[1] Martín, V, I.; Rodríguez, A.; Graciani, M. M.; Robina, I.; Carmona, A.; Moyá, M. L. J. Colloid Interface
Sci. 2011, 363, 284-294.
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P35 Synthesis and physicochemical characterization of alkanedyil-
bis(dimethyldodecylammonium) bromide, 12-s-12,2Br-, surfactants with s=7, 9 ,11 in aqueous medium
Victoria I. Martín*, Amalia Rodríguez, Alfredo Maestre and María Luisa Moyá
Department of Physical Chemistry, University of Seville, C/Profesor García González 1, 41012 Sevilla. *[email protected]
Menger et al. and Zana et al. have prepared and characterized the didodecyl dicationic dibromide dimeric surfactants with different methylene spacer lengths, 12-s-12,2Br-, with s=2, 3, 4, 5, 6, 8, 10, 12, 14 and 16 [1,2]. Our group has been interested in the study of micellar growth in 12-s-12,2Br- aqueous micellar solutions in the absence as well as in the presence of various additives such as alcohols, organic polar solvents and monomeric surfactants. An increment in the dimeric surfactant concentration causes a morphological transition from spherical to elongated micelles and the [surfactant] where the change in size and shape of the micelles occur is called the second cmc, C*. It was found that 12-s-12,2Br- dimeric surfactants with an even number of methylenes in the spacer show smaller C* values than those with an odd number of –CH2- units in the spacer [3]. Besides, an endothermic enthalpy change accompanying the morphological transition was found for even spacers whereas an exothermic enthalpy change was found for odd spacers. In order to investigate this point further, the preparation and characterization of new 12-s-12,2Br- surfactants with an odd number of methylenes in the spacer was required. In this work the didodecyl dicationic dibromide dimeric surfactants 12-s-12,2Br-, with s=7, 9, and 11 were prepared and characterized and their properties compared to those of 12-s-12,2Br- surfactants with s=2, 3, 4, 5, 6, 8, 10, and 12.
Figure caption: Dependence of ln cmc on the number of methylene units in the spacer for 12-s-12,2Br- dimeric surfactants at 303 K. Inset: Dependence of ln cmc on the number of methylenes in the head group for
monomeric CH3(CH2)11N+(CH3)2(CmH2m+2),Br- at 298 K. The cmc´s are expressed as mole fractions.
Acknowledgments. This work was financed by the DGCYT (grant CTQ2009-07478), the European Union and Consejería de Innovación, Ciencia y Empresa de la Junta de Andalucía (FQM-274 and P07-FQM-03056).
[1] Menger, F. M.; Keiper, J. N. Angew. Chem. Int. Ed. 2002, 39, 1906. [2] Zana, R. J. Colloid Interface Sci. 2002, 248, 203. [3] Rodríguez, A.; Graciani, M. M.; Martín, V. I.; Robna, I.; Moyá, M. L. J. Phys. Chem. B 2010, 114,
7817.
s (number of C atoms in the spacer)0 2 4 6 8 10 12
lncm
c
-14.5
-14.0
-13.5
-13.012-s-12,2Br-
0 2 4 6 8-11
-10
-9
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m (number of C atoms in the head group)
lncm
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CH3-(CH2)11N(CH3)2(CmHm+2),Br-
POLYMERS, POLYELECTROLYTES, SURFACTANTS AND GELS 180
P36 A comparative thermodynamic analysis of clouding phenomenon in mixtures of
sugar-based surfactants with Triton X-100 J. A. Molina-Bolívar, M. Naous, J. M. Hierrezuelo, C. Carnero-Ruiz*
Department of Applied Physics II, University of Málaga, 29071-Málaga, Spain *[email protected]
In the present communication we report a comparative study on the thermodynamic of clouding phenomenon in mixed micelles of MEGA-10/Triton X-100 and OTG/Triton X-100. The cloud point variation of mixed micelles with the Triton X-100 content has been determined and the energetic parameters of the process have been estimated. The study was performed in water and in the presence of NaCl. The cloud point of a nonionic surfactant can be considered as the limit of its solubility as the phase separates at temperatures above the cloud point [1,2]. The clouding species release their solvated water and separate out from the solution. The presence of sugar surfactant monomers in the mixed micelle enhances the cloud point of the system, being more pronounced in the case of OTG surfactant. Addition of increasing amount of NaCl to micellar solution causes a continuous decrease in the cloud point due to a marked alteration of the hydration layer of micelles provoked by the presence of electrolyte. For all solutions the values of 0
CPG were positive and similar for both sugar-based surfactants. The values of 0
CPH and 0CPS are higher for OTG/Triton X-100 mixed micelles
than for MEGA-10/Triton X-100 system. The cloud point process is exothermic in nature for the mixed micellar system, as proven by the negative value of 0
CPH . The exothermicity of the clouding process is due to the aggregation of weakly hydrated micelles and their phasing out into the condensed phase. The process is more exothermic as the presence of the sugar-based surfactant in the mixed micelle increases (with and without NaCl in the solution). Furthermore, the negative values of 0
CPS indicate that the association of micelles in the clouding phenomenon is entropically unfavorable, that is, the process is accompained with an increase in the order of the micellar system. For a given proportion of Triton X-100 in the mixture, for both sugar-based surfactants, the NaCl increases the randomness of the system and hence 0
CPT S value becomes less negative. It was observed from the enthalpy-temperature plots that the change in heat capacity of clouding phenomenon is negative, indicating the important role played by dehydration in this thermodynamic process. The enthalpy-entropy compensation plots are examined and found to exhibit an excellent linearly for this process. This means that the change of enthalpy is almost compensated by a corresponding change in entropy resulting in a smaller net free energy change. The micelle-water interactions were characterized from the compensation temperatures, TC, which were evaluated from the slope of the compensation lines. The values of TC decreases with NaCl concentration, which is attributed to the fact that the presence of the electrolyte in the medium significantly alters the micellar hydration layer.
Acknowledgements: This work has been financially supported by the “Consejería de Innovación, Ciencia y Empresa de la Junta de Andalucía” (Project P07-FQM-02762).
[1] Molina-Bolívar, J. A.; Hierrezuelo, J. M.; Carnero Ruiz, C., J. Chem. Thermodynamics 2013, 57, 59. [2] Molina-Bolívar, J. A.; Carnero Ruiz, C., Fluid Phase Equilibria 2012, 203, 58.
POLYMERS, POLYELECTROLYTES, SURFACTANTS AND GELS 181
P37 Morphological and protein binding studies in lysine-based self-assembled
nano/micro-tubes Isabel S. Oliveira, Maria J. Araújo and Eduardo F. Marques*
Centro de Investigação em Química, Department of Chemistry and Biochemistry, Faculty of Science, University of Porto (Portugal)
Besides their self-assembly into micelles, vesicles and liquid-crystalline phases of different nature, amino acid-based amphiphiles have the possibility of forming supramolecular aggregates, such as tubules, fibers and ribbons, due to the common presence of a chiral centre (the amino acid chiral carbon) and hydrogen bonding at the headgroups. These self-assembled nano/micro-tubules have high potential as nanocarriers, due to their unique morphology that is able of efficiently loading biomolecules such as DNA, drugs and proteins. [1]
In this work, we have synthesized a family of double-chained anionic surfactants derived from the amino acid L-lysine, with variable degree of chain length mismatch. Previous works have shown that this type of lysine-based surfactants have relatively low levels of ecotoxicity and hemolysis, and may form tubules and stable vesicles in catanionic mixtures. [2,3] The compounds are designated simply by m(Lys)n, with both the total chain length (m+n) and the length of the two chains in the same molecule having been made different (m�n). The thermodynamic parameters of the phase transitions in solution have been determined by micro-DSC. The interaction of the derivatives of lysine with different proteins, under different experimental conditions, was further investigated by polarized light microscopy, fluorescence microscopy, AFM and cryo-SEM, with the aim of characterizing in detail the fine structure of the m(Lys)n/protein aggregates formed.
Figure caption: 8Lys16 0.5% w/w aqueous dispersions: a) light micrograph showing tubular aggregates with
helicoidal structure (bar: 20 μm); b) cryo-SEM micrographs (bar: 1 μm); c) mechanisms for tubule formation; d) DSC thermograms showing endothermic isotropization peaks.
Acknowledgements: We kindly acknowledge the Portuguese Science Foundation (FCT) and FEDER-Compete for financial support through projects PTDC/QUI-QUI/115212/2009 and Pest/C-QUI/UI0081/2011. [1] Zarif, L., J. Control. Release 2002, 81, 7-23. [2] Brito, R. O.; Marques, E. F.; Silva, S. G.; Vale, M. L.; Gomes, P.; Araújo, M. J.; Rodriguez-Borges, J. E.; Infante,
M. R.; Garcia, M. T.; Ribosa, I.; Vinardell, M. P.; Mitjans, M., Colloids Surf. B: Biointerfaces 2009, 72, 80-87. [3] Marques, E. F.; Brito, R. O.; Silva, S. G.; Vale, M. L.; Gomes, P.; Araújo, M. J.; Söderman, O., Langmuir 2008,
24, 11009-11017.
POLYMERS, POLYELECTROLYTES, SURFACTANTS AND GELS 182
P38 Shake induced gelation of Particle-Polymer dispersions
R. Perea1, M. M. Ramos-Tejada1,* and P. Luckam2
1University of Jaén, Department of Physics, 23071 Jaén, Spain. 2Imperial College of Science, Technology and Medicine. Dept Chem. Eng. and Chem. Tech., SW72BY,
London,United Kingdom *[email protected]
Some dispersions of clay and silica particles in water in the presence of high molecular weight polyethyleneoxide (PEO) that at rest are fluid, after a quick shake become solid [1-4], so much so that, in some cases, they can be played with in the hands, see Figure 1.On leaving the dispersions for a certain period of time, minutes to days depending on the polymer molecular weight and concentration, the dispersions become liquid-like again. These dispersions have been called “shake gels”.We have observed that it is possible a strong gel formation under a moderate shake of the sample studied but not under a moderate shear rate. Besides, we have found that the gel can be easily formed when we squirt the sample through a hypodermic needle. This seems to indicate that the extensional shear could play an important role in the gel formation. A number of physical variables are also determinant for producing the gel and controlling its behaviour. In this work, we have studied the effect of the shape and size of the particles on the shake gel formation.To that aim, we have mapped the “phase” behavior of silica (Ludox TM50), bentonite and laponite dispersions in presence of PEO. At low �t (ratio between the total mass of PEO and the total area of clay surface) no shake gel was formed, but as �t was increased, close the surface saturation, the shake gel effect is observed, and at still higher �t, shake gels no longer form. The upper limit of PEO concentration for shake gel formation seems to depend of the particle shape. Whereas in the case of the disc-shaped particles (laponite and bentonite) the upper limit is around the saturation concentration, in the case of spherical particles (Ludox) this limit is around 2/3 of the particle surface saturation. On the other hand, we have observed important differences between bentonite (platelets of approximately 1000 nm x 1 nm dimensions) and laponite (platelets of approximately 30 nm x 1 nm dimensions) dispersions. When we shaked the former, we found in most cases an important and irreversible phase separation; on the contrary, in the case of the laponite dispersion the phase separation is not extensive and it is easily reversible.These results can contribute to the understanding of the shake gel formation. Figure caption: Aqueous LudoxTM-50-PEO mixture contains 25% of silica and 0.4% PEO Mw~4000000. (A)
before shake it;(B) after completion of shaking.
Acknowledgements: Financial support by Junta de Andalucía, Spain (Project PE2008-FQM3993) and Spanish Ministry of Science and Innovation (FIS2010-19493) is greatly acknowledged.
[1] Cabane, B.; Wong, K.; Lindner, P.; Lafuma, F., J. Rheol.1997, 41(3), 531-547. [2] Liu, S. F.; Lafuma, F.; Audebert, R., Colloid Polym. Sci. 1997, 272(2), 196-203. [3] Pozzo, D. C.; Walker, L. M., Colloids and Surfaces A: Physicochem. Eng. Aspects 2004, 240, 187-198. [4] Zebrowski, J.; Prasad, V.; Zhang, W.; Walker, L. M.;Weitz, D. A., Colloids and Surfaces A: Physicochem.
Eng. Aspects 2003, 213, 189-197.
POLYMERS, POLYELECTROLYTES, SURFACTANTS AND GELS 183
P39 Permeability-Tunable Microgels
Benjamín Sierra-Martín1, Ana Maldonado-Valdivia1,*, Antonio Fernández-Barbero1 1Group of Complex Fluids Physics and NanoLab,
University of Almería, 04120 Almería, Spain. *[email protected]
We study the electrophoresis of a thermo-sensitive and ionic microgel and demonstrate its free-draining character when the polymer network is ionized, in contrast to the more conventional charged hard spheres or neutral microgels. The results are rationalized by considering the Ohshima theory for polyelectrolyte-coated particles; the electrophoretic mobility is determined by the balance between the particle charge and the friction coefficient, which in turns depends on the particle swelling and viscosity. Interestingly, we find that the viscosity affecting the particle permeability is associated to the local environment of the network; it shows power law dependence with the salt concentration,
c0.2 and account for the different c scaling. These experiments can be used as a strategy to explore the viscosity of water molecules inside the microgel, being complementary to other direct methods such as nuclear magnetic resonance.
Acknowledgements: This work has been funded by the Spanish Ministerio de Economía y Competitividad/FEDER (project MAT2011-28385), Andalusian Government/FEDER (Project P010-FQM 06104) and EU-COST-Action CM1101.
POLYMERS, POLYELECTROLYTES, SURFACTANTS AND GELS 184
P40 Rational design of cleavable cationic gemini surfactants: exploring the
multifunctionality of serine as headgroup Sandra G. Silva1, Cláudia Alves1, Ana M. S. Cardoso2, Amália S. Jurado2,3,
Maria C. Pedroso Lima2,3, M. Luísa C. do Vale1,*, Eduardo F. Marques1,* 1Centro de Investigação em Química (UP), Department of Chemistry and Biochemistry, Faculty of
Science, University of Porto, Rua do Campo Alegre s/n, P-4169-007, Porto, Portugal. 2CNC - Centre for Neuroscience and Cell Biology, University of Coimbra, Portugal.
3Department of Life Sciences, University of Coimbra, Portugal. *[email protected]; *[email protected]
Gemini surfactants have emerged as a new class of self-asssembling molecules in the 1970s and since then have attracted considerable interest both in fundamental and in applied contexts. Cationic gemini surfactants are of particular interest owing to their potential for biomedical applications. The conventional bis-quats have proved to be highly promising in delivering genetic material to cells and as synthetic additives in liposome formulations for drug delivery.[1] However, they often exhibit relatively high levels of cytotoxicity and skin irritancy, both detrimental to their use in biomedical applications. Therefore, considerable efforts have been made to design and synthesize novel gemini surfactants, possessing enhanced toxicological profiles, by using biomolecules (sugars, amino acids and peptides) as polar headgroup.
In this context, our research team has been engaged in the synthesis and physicochemical evaluation of amino acid based monomeric and dimeric surfactants. [2, 3] In the present work, the results obtained with the amine series and two novel series of cationic gemini surfactants based on serine are presented. The novel surfactants have a cleavable amide or ester bond between the polar head group and the spacer. [4] The effects of molecular structure, nature of spacer linkage and spacer length on the interfacial and cytotoxic properties of these gemini surfactants are presented. The compounds show enhanced interfacial properties and lower cytotoxicity, in comparison with conventional bis-quat gemini and monomeric surfactants, which demonstrates the possibility of their use in technical and biological applications.
Figure caption: Molecular structures of serine-based gemini surfactants
Acknowledgements: Thanks are due to Portuguese Science Foundation (FCT) and FEDER-Compete for financial support through PTDC/QUI-BIQ/103001/2008, PTDC/QUI-QUI/115212/2009, REDE/1517/RMN/2005, Pest/C-QUI/UI0081/2011. SGS and AMSC acknowledge FCT for PhD grants SFRH/BD/61193/2009 and SFRH/BD/63288/2009, respectively.
[1] Cardoso, A. M. S.; Faneca, H.; Almeida, J. A. S.; Pais, A.; Marques, E. F.; de Lima, M. C. P.; Jurado, A. S., Biochim. Biophys. Acta 2011, 1808, 341.
[2] Silva, S. G., Rodríguez-Borges, J. E., Marques, E. F., do Vale, M. L. C., Tetrahedron 2009, 65, 4156-4164. [3] Silva, S. G., Fernandes, R. F., Marques, E. F., do Vale, M. L. C., Eur. J. Org. Chem. 2012, 345-352. [4] Silva, S. G.; Alves, C.; Cardoso, A. M. S.; Jurado, A. S.; Pedrodo de Lima, M. C.; Vale, M. L. C. Marques, E. F.,
Eur. J. Org. Chem. 2013, 1758-1769.
POLYMERS, POLYELECTROLYTES, SURFACTANTS AND GELS 185
P41 Kinetics And Mechanisms of Thermal Degradation of Water Borne
Poly(BA/MMA)/Graphene Composites D. Spasevska1, Alejandro Arzac3, J. Blazevska-Gilev 1, R. Fajgar2 and R. Tomovska3,4,*
1Faculty of Technology and Metallurgy,”Ss.Cyril&Methodius” University, 1001 Skopje, R.of Macedonia.
2Institute of Chemical Process Fundamentals of the ASCR, v. v. i., Department of Aerosols and Laser Studies, Rozvojová 135, 165 02 Prague 6, Czech Republic
3POLYMAT and Departamento de Química Aplicada, Facultad de Ciencias Químicas, University of the Basque Country UPV/EHU, Joxe Mari Korta zentroa, Tolosa etorbidea 72, Donostia-San Sebastián
20018, Spain 4IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Spain.
The aim of this research is to study thermal stability of the water borne poly(methyl methacrylate/butyl acrylate) p(BA/MMA)/graphene nanoplateltes (GNPs) composites, prepared by emulsion mixing technique [1,2]. The polymer latex with 40 % solid content, composed from p(MMA/BA), in ratio 50/50 wt%, was synthesized by a seeded semicontinuous emulsion polymerization. The GNPs were dispersed in water by means of sonication in presence of polyvinyl pyrrolidone (PVP) and afterward mixed with the polymer latex in order to obtain hybrid aqueous dispersions with GNPs content of 0.5 wt%, 1 wt%; 2 wt%; and 3 wt% in relation to polymer. The composite films were prepared by water evaporation under standard ambient conditions and characterized by means of Raman spectroscopy, Fluorescence Quenching Microscopy (FQM) and SEM imaging, while thermal properties of the composites were studied by Thermo Gravimetric Analysis (TGA).
The TGA analyses have been performed by heating at two different rates up to around 723 K. The results have been used for making kinetic study of the thermally activated process of P(BA/MMA)/graphene composites degradation. As the easily measured weight changes of the samples in the defined thermal conditions are a suitable sensor for their structural and chemical changes, by means of a method of like Gropjanov’s one, the useful information for identifying the kinetic parameters of the investigated process taking place in the course of thermal treatment have been obtained [3].
The thermal variation of the rate constant as well as the kinetic equations for the examined process depending on the GNPs content in the composites has been derived. The activation energies of the composites are determined and their dependence on the GNPs content is discussed. As well, the controllable mechanism of the examined process has been determined [4].
[1] Yousefi, N.; Gudarzi, M. M.; Zheng, Q.; Aboutalebi, S. H.; Sharif, F.; Kim, J. -K.; J.Mater.Chem. 2012, 22 12709.
[2] Syurik, Y.V.; Ghislandi, M.G.; Tkalya, E.E.; Paterson, G.; McGrouther, D.; Ageev, O.A.; Loos, J.; Macromol. Chem. Phys. 2012, 213, 1251�1258.
[3] Gropjanov, V. M.; Abbakumov, V. G.; Him.i him.tehnol. 1975, 18, 2, 202. [4] Hillier, J.; Bezzant, T.; Fletcher, T. H.; Energy Fuels, 2010, 24, 2841-2847.
SOFT COLLOIDS. SOFT NANOTECHNOLOGY. BIOINSPIRED SYSTEMS 186
P42 Poly(N-vinylcaprolactam) nanogels: A light scattering study
José Callejas-Fernández1,*, Josetxo Ramos2, Ainara Imaz2, Jacqueline Forcada2, Manuel Quesada-Pérez3, Arturo Moncho-Jordá1
1Departamento de Física Aplicada, Facultad de Ciencias, 18071 Granada (Spain). 2 POLYMAT, Bionanoparticles Group, Departmento de Química Aplicada, UFI 11/56, Faculty of
Chemistry, University of the Basque Country UPV/EHU, Apdo. 1072, 20080 Donostia (Spain). 3Departamento de Física, Escuela Politécnica Superior, 23700 Linares, (Spain).
Nowadays, nano/microgels formed by biocompatible polymers emerge as promising particles in the field of biomaterials-biomedicine. Polyvinylcaprolactam nanogels (PVCL) belong to this class of nanoparticles. They can vary their size in response to external stimuli as temperature, pH, solvent properties, external fields, among others. In this work, a light scattering (LS) study on charged and uncharged PVCL anionic nanogels in water is presented. The goal of the research is to discuss on the validity of LS methods to explore both “individual” properties of nanogels (size, shape, internal structure) and “bulk” properties as the structure of its colloidal dispersions.
Figure caption: Experimental form factor corresponding to a PVCL nanogel at different temperatures.
Acknowledgements: This work is supported by Spanish Plan Nacional de Materiales, Projects: MAT2012-36270-C01, -C02 and –C04 and MAT2009-13155-C04-02.
[1] Ramos, J.; Imaz, A.; Forcada, J., Polym. Chem. 2012, 3, 852-856. [2] Ramos, J; Imaz, A.; Callejas-Fernández, J.; Barros-Barbosa, L.; Estelrich, J.; Quesada-Pérez, M.;
Forcada, J., Soft Matter 2011, 7, 5067-5082.
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SOFT COLLOIDS. SOFT NANOTECHNOLOGY. BIOINSPIRED SYSTEMS 187
P43 New sorbents based on silica-carrageenan hybrids
Rui S. Carvalho*, Daniela S. Tavares, Ana L. Daniel-da-Silva and Tito Trindade
CICECO-Chemistry Department, Aveiro Institute of Nanotechnology, University of Aveiro, 3800-193 Aveiro, Portugal
The discharge of dyes and toxic metal ions in water supplies is a matter of concern due their harmful impact on the environment. In the last years a number of nanoengineered materials have emerged as new sorbents for water decontamination. Examples include the use of magnetic silica nanoparticles functionalized with dithiocarbamate groups for the removal of Hg2+ [1] and nanoparticles coated with biopolymers obtained from renewable resources to remove dyes [2]. This research has focus on the development of silica-biopolymer hybrids that merge the above described functionalities, aiming their application as sorbents in water purification processes.
Hybrid materials comprising amorphous SiO2 and dithiocarbamate derivatives and the polysaccharide �-carrageenan were synthesized, in the form of bulk materials and nanocomposite particles. Siliceous-polysaccharide hybrids (bulk form) were synthesized by hydrolytic co-condensation of tetraethyl orthosilicate (TEOS) and a siloxydithiocarbamate (SiDTC) precursor in aqueous solutions of �-carrageenan (2 wt%). The resulting solution formed gels, at room temperature, due to the gelling properties of �-carrageenan. Differential scanning calorimetry (DSC) analysis showed that hybrid materials undergo an endothermic transition upon heating, due to gel-to-sol transition. The ATR-FTIR spectra of dried gels was in agreement with the presence of a siliceous network in the carrageenan gel, and indicates the presence of the dithiocarbamate groups in those gels prepared using SiDTC.
In a second step these hybrid materials were confined to nanometric dimensions using water-in-oil microemulsions. Carrageenan hydrogel nanoparticles were first prepared in microemulsions comprising n-heptane as the organic solvent, cetyltrimethylammonium bromide (CTAB) as surfactant and 1-butanol as the co-surfactant and in the presence of magnetite nanoparticles [3]. The magnetic hydrogel nanoparticles were then encapsulated in amorphous siliceous shells, by performing the hydrolytic co-condensation of TEOS and SiDTC within microemulsion droplets. The spherical morphology of the resulting composite nanoparticles was confirmed by electron microscopy, with particles showing an average diameter of 60 nm. The use of these hybrid materials for the magnetic removal of contaminants from water will be discussed, namely by considering the chemical functionalities associated to their composition. For example, the presence of dithiocarbamate groups as suitable chelating moieties for metal ions removal and the presence of sulfonate groups from carrageenan to attach electrostatically cationic dyes. Acknowledgements: FCT - Fundação para a Ciência e Tecnologia (PTDC/CTM-NAN/120668/2010, Pest-C/CTM/LA0011/201) FSE and POPH for funding. We thank the RNME (National Electronic Microscopy Network) for TEM facility.
[1] Girginova, P. I.; Daniel-da-Silva, A. L.; Lopes, C. B.; Figueira, P; Otero, M.; Amaral, V. S.; Pereira, E.; Trindade, T. J. Colloid Interface Sci., 2010, 345, 234-240.
[2] Crini G., Progr. Polym. Sci., 2005, 30, 38-70. [3] Daniel-da-Silva, A. L.; Fateixa, S.; Guiomar, A. J.; Costa, B. F. O.; Silva, N. J. O.; Trindade, T.;
Goodfellow, B. J.; Gil, A. M., Nanotechnology 2009, 20, 355602.
SOFT COLLOIDS. SOFT NANOTECHNOLOGY. BIOINSPIRED SYSTEMS 188
P44 Lysine based cationic surfactants at the air-water interface. Mixed monolayers
with DPPC: An investigation into the antimicrobial activity Aurora Colomera, Lourdes Pereza, Maria Rosa Infantea, Ramon Ponsa, Angels Manresab,
Maria Jose Espunyb, Aurora Pinazoa,*
a Department de Tecnologia Química i de Tensioactius, Institut de Química Avançada de Catalunya, CSIC. Jordi Girona 18, 08034 Barcelona, Spain
b Laboratori de Microbiologia, Facultat de Farmàcia, Universitat de Barcelona. Av. Joan XIII s/n, 08028 Barcelona, Spain
Antimicrobial resistance to antibiotics is a major global public health threat, thus development of new antimicrobial compounds is of great significance in biomedicine chemistry. Cationic surfactants exhibit antimicrobial activity and have been used as disinfectants in hospitals and in food and pharmaceutical industry. These types of applications require compounds that do not present hemolytic or cytotoxic activities. To search for new antimicrobial agents, our group has synthesized cationic surfactants from different amino acids. Amino acid based surfactants can be prepared from renewable raw materials and are characterized by their high biodegradability and moderate toxic levels.
We report studies that contribute to elucidate the relationship between surface activity of three lysine based surfactants and their antimicrobial activity. To this end, the adsorption properties at the air/liquid interface of spread monolayers were studied. Under saline conditions their spread monolayers can be compressed. Mixed monolayers with DPPC showed an expansion of the DPPC monolayer which suggests interactions of the compounds with DPPC molecules that strongly depend on the surfactant structure. The antibacterial activity against Staphylococcus aureus and Escherichia coli bacteria has been performed by electron microscopy observation. The three surfactants caused multiple forms of damage as evidenced by structural alterations, leakage of internal material and cell destruction on the bacteria.
SOFT COLLOIDS. SOFT NANOTECHNOLOGY. BIOINSPIRED SYSTEMS 189
P45 Supramolecular aggregation in cationic/anionic mixtures of
calixarene and serine-based surfactants Catarina Costa1, Vitor Francisco2, M. Luísa C. do Vale1, Luis Garcia-Rio2,*,
Eduardo F. Marques1,* 1Centro de Investigação em Química, Department of Chemistry and Biochemistry, Faculty of Science,
University of Porto, Rua do Campo Alegre, s/n, P-4169-007 Porto, Portugal. 2Centro Singular de Investigación en Química Biológica y Materiales Moleculares (CIQUS),
Dept. of Physical Chemistry, University of Santiago de Compostela, Santiago de Compostela, Spain. *[email protected]; *[email protected]
Nano-structured assemblies of variable complexity—such as tubules, fibers, micelles, vesicles, and disks—can be created through molecular self-organization of small organic compounds and conventional amphiphiles, making use of noncovalent interactions [1]. The macrocycle p-sulfonatocalix[4]arene (SC4), is a known receptor for organic ammonium cations in aqueous solution, showing strong binding ability for these guests due to their -rich cavity and additional anchoring points offered by the sulfonate groups. In a previous work, we have studied the interactions in aqueous solution between SC4 and tetradecytrimethylammonium bromide (a micelle-forming surfactant), showing the formation of giant unilamellar vesicles after sonication of mixed SC4-TTAB dispersions [2]. These vesicles could be stored without use of cryo-protectants by lyophilization, and then rehydrated without change size or shape. In this work, we have explored the self-assembling properties of mixtures of SC4 with cationic serine-based surfactants, with C16 and C12 alkyl chains (termed 16Ser and 12Ser, respectively). For the Ser16/SC4 system, in dilute aqueous solution (less than 20 mM), we have found that there is a range of mixing ratios where flexible supramolecular tubules, with a few μm long, are formed (Figure A-C). The formation process is slow (some days) and the aggregates appear in fast Brownian motion, apparently breaking into and reforming from spherical aggregates (presumably liposomes). Both Ser16/SC4 and Ser12/SC4 mixed systems have been studied by surface tension, light microscopy, cryo-SEM and NMR, and the conspicuous aspects of supramolecular aggregation therein found will be presented and tentatively rationalized. Figure caption: Supramolecular Ser16/SC4 tubules: light microscopy (A and B) and cryo-SEM (C). E) Possible interaction between the two molecules and respective bilayer formation. Bar: A, B - 20 μm; C - 6 μm.
Acknowledgments: Thanks are due to the Portuguese Science Foundation (FCT) and FEDER-Compete for financial support through projects PTDC/QUI-QUI/115212/2009 and Pest/C-QUI/UI0081/2011. V. F. acknowledges FCT for the PhD Grant SFRH/BD/43836/2008.
[1] Shimizu, T.; Masuda, M.; Minamikawa, H.; Chem. Rev. 2005, 105, 1401-1444. [2] Francisco, V.; Basilio, N.; Garcia-Rio, L.; Leis, J.R.; Marques E.F.; Vázquez-Vázquez, C.; Chem. Comm., 2010,
46, 6551–6553.
SOFT COLLOIDS. SOFT NANOTECHNOLOGY. BIOINSPIRED SYSTEMS 190
P46 The role of the ionic specificity on the nanogel aggregation
Verónica D.G. González1, Delfina Bastos González2, José Callejas Fernández2, María Tirado Miranda2,*
1INTEC (Universidad Nacional del Litoral – CONICET), Santa Fe, Argentina 2Universidad de Granada, Dpto. Física Aplicada, Campus Fuentenueva s/n, 18071 Granada Spain
Nanogels are cross-linked polymeric chains dispersed in water that are able to swell or deflate in response to changes in external triggers such as pH, temperature and biomolecules. This behaviour makes them useful for applications in fields such as drug delivery, regenerative medicine, nanopatterning and chemical biosensing [1].
In this work, we focused on thermosensitive nanogels composed of poly(N-isopropyl acrilamide). This system has a lower critical solution temperature, around 32 ºC in aqueous solutions. Thus, the nanogel swells at low temperatures and collapses at high ones [2]. We studied the aggregation kinetics and morphological properties of nanogels as function of temperature, ionic specificity and electrolyte concentration. Depending on the nature of the ion employed, we found a variety of behaviour ranging from no aggregation to DLCA regime. However, the ionic specificity revealed an equilibrium distribution of clusters-nanogels for determined experimental conditions. This equilibrium distribution was able to keep up to 100 minutes and then, the aggregation process continued spontaneously.
Acknowledgement: Financial support from the Ministerio de Economía y Competitividad of Spain (project No. MAT2012-36270-C04-02).
[1] Saunders, B.R., Laajam, N., Daly, E., Teow, S., Hu, X., Stepto, R., Adv. Colloid Interface Sci. 2009, 147, 251-262.
[2] López-León, T., López-López, J. M., Odriozola, G., Bastos-González, D., Ortega-Vinuesa, J. L., Soft Matter 2009, 6, 1114-1116.
SOFT COLLOIDS. SOFT NANOTECHNOLOGY. BIOINSPIRED SYSTEMS 191
P47 Rhamnolipid characterization and its influence on dppc bilayer organization(
poster, bioinspired systems) E. Haba1, R. Pons2, L. Pérez2, A. Manresa1, A. Pinazo2,*
1Laboratori de Microbiologia, Facultat de Farmàcia, Universitat de Barcelona. Av. Joan XIII s/n, 08028 Barcelona, Spain
2Department de Tecnologia Química i de Tensioactius, Institut de Química Avançada de Catalunya, CSIC. Jordi Girona 18, 08034 Barcelona, Spain
The pressing need for more biosustainable, biocompatible and biodegradable surfactant based products make the study of biosurfactants an important area of research. Biosurfactants are surface active biomolecules that are produced by a variety of different microorganism. Rhamnolipids produced by Pseudomona aeruginosa consist of one or two rhamnose molecules linked to one or two molecules of hydroxydecanoic acid. Rhamnolipids have the two main properties of surfactants, show strong surface activity and self assembly in water. Understanding their fundamental physico chemical properties and how these relate to their biological roles are keys to their wider exploitation. Despite the importance that the interaction between rhamnolipids and membranes might play in their biological mechanism of action very little is known, especially regarding rhamnolipid-phospolipid molecular interactions. The aim of this work was to study the ability of RL8 mixture to form vesicles in absence and presence of the phospholipid DPPC. We employed size and Z- potential to characterise the size and the external charge of the vesicles and SAXS to measure the vesicle bilayers characteristics. The biosurfactant forms ordered bilayers with long repeating distances, these long repeating distances are stabilized by the charging of the bilayer and also by a strong fluidity of the bilayers. The ability of RH to increase the fluidity of DPPC bilayers may be related with the strong hemolytic power of these molecules
SOFT COLLOIDS. SOFT NANOTECHNOLOGY. BIOINSPIRED SYSTEMS 192
P48 Structure and plasmon coupling of 2D Au@PNiPAM microgel arrays with
thermally controlled interparticle gap Ana Maldonado-Valdivia1,*, Joaquim Clara-Rahola1, Rafael Contreras-Cáceres1,
Benjamín Sierra-Martín1, Antonio Fernández-Barbero1 1Group of Complex Fluids Physics and NanoLab,
University of Almería, 04120 Almería, Spain. *[email protected]
2D nanoparticle arrays are fabricated using core-shell Au@PNiPAM nanoparticles. The PNiPAM shells act as tunable temperature-sensitive mechanical spacers, just to set the interparticle gaps. Deviation from linearity due to the soft nature of the polymer shells is found between gaps into the arrays and those expected from the (colloidal) particle sizes at bulk. This lack of linearity transfers to the particle structures making the ensembles better ordered at high temperature, contrary to the classical behavior for harder particles. Vertical plasmon coupling between the particle cores and an Au substrate becomes apparent during the deswelling-drying process, while any horizontal lateral coupling between the Au cores is detected. The polymer around the Au cores is finally removed from the 2D ensembles, keeping the arrays their mechanical stability.
Acknowledgements: This work has been funded by the Spanish Ministerio de Economía y Competitividad/FEDER (project MAT2011-28385), Andalusian Government/FEDER (Project P010-FQM 06104) and EU-COST-Action CM1101.
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P49 Influence of xenobiotics on the stability of natural micellar aggregates
J. Morales1,*, J. A. Manso1, M. Arias-Estevez2 and J. C. Mejuto1
1Physical Chemistry Department, University of Vigo, 32004 Ourense, Spain. 2Plant Biology and Soil Science Department, University of Vigo, 32004 Ourense, Spain.
Humic acids (HAs) are the principal component of humic substances, which are the major organic constituents of soil [1]. They change the soil characteristics, favouring the ion exchange [2] and the absorption of nutrients. Organic matter in soil also facilitates the adsorption mechanisms of hazardous substances as pesticides [3]. It was determined by dynamic light scattering that there is a correlation between some Physical-Chemistry characteristics of these natural colloidal aggregates (from extracts of soil’s humic substances) as the conductivity, the polidispersity, the mobility, the particle size and especially the Zeta potential and its high impact on chemical reactivity with xenobiotics. The excess of electrical charge at the interface is responsible for surface conductance and it is a good parameter to evaluate the stability of these humic substances. Its colloidal behaviour can be significantly influenced by the solution pH [4]. The appearance of pesticides in the medias analyzed causes a decrease on the stability of natural aggregates colloidal, more pronounced at lower HAs concentrations. Thus modifying some of its properties associated with its colloidal nature. The inclusion of carbofuran shows greater destabilization on the system than the metalaxyl inclusion.
Figure caption: (left). Influence of humic acids concentration on the Zeta potential at pH=9 in absence of pesticide. Nitric acid was used as acid titrator and sodium hydroxide as alkaline. T= 25 (right). Variation of Z-potential in the humic colloidal aggregates. [Pesticide]=0.005 M; [HAs]=0.02 g·L-1: in absence of pesticide ( ), in the presence of carbofuran ( ) and in the presence of metalaxyl ( ). Acknowledgements: The authors thank the Xunta de Galicia (10PXIB383187PR) for financial support. Jorge Morales thanks the University of Vigo for a research-training grant (P.P. 0022 122I 641.03).
[1] Stevenson, F. J. Humus Chemistry: Genesis, Composition, Reactions. John Wiley & Sons: NY, 1994. [2] Zhou, P.; Yan, H.; Gu, B., Chemosphere 2005, 58, 1327-1337. [3] Briceño, G.; Palma, G.; Durán, N., Crit. Rev. Environ. Sci. Technol. 2007, 37, 233-271. [4] Ghosh, S.; Mashayekhi, H.; Pan, B.; Bhowmik, P.; Xing, B., Langmuir 2008, 24, 12385-12391.
SOFT COLLOIDS. SOFT NANOTECHNOLOGY. BIOINSPIRED SYSTEMS 194
P50 Stability of carbofuran in restricted aqueous media
J. Morales1,*, J. A. Manso2, A. Cid3, M. A. Iglesias-Otero1 and J. C. Mejuto1
1Physical Chemistry Department, University of Vigo, 32004 Ourense, Spain. 2Cancer Research Center, 37007 Salamanca, Spain
3Chemistry Department, REQUIMTE-CQFB, University Nova of Lisbon, 2829-516 Monte de Caparica, Portugal.
Carbofurans (CFs) are chemically carbamic acid derivatives and they have been employed successfully as insecticides because of the capability for controlling pests [1].
In agriculture, composition of the soil can be variable. Presence of restricted water environments carries that soil compounds and structure influences hardly the action of these carbamates, that furthermore posses an important toxicity [2].
In this work it is showed the influence of some oil/water microemulsions on the stability of different CFs (3-Hydroxyc-arbofuran (HCF) and 3-Keto-carbofuran (KFC) shown in Figure) in basic media. The behavior under the action of aqueous media is analyzed using a pseudophase model [3].
For CF and HCF was found that presence of water in restricted media implies an rise of its basic degradation. On the contrary, for KCF, an inhibition was observed. This main difference can be explained due to the absence of electronic conjugation of the basic hydrolysis products in microemulsions because to the presence of strong hydrogen-bond interactions.
Figure caption: Chemical structures of carbofuran and two of its derivatives: 3-Hydroxyc-arbofuran (HCF) and 3-Keto-carbofuran (KFC)
Acknowledgements: Morales and Iglesias-Otero thanks thanks University of Vigo for a research grant. Dr. Cid thanks to MCTES-FCT (Portugal) his post-doctoral grant (SRFH/BPD/78849/2011),
[1] Alvares, A. P.; in: B. Ballantyne, T.C. Marrs (Eds), Clinical and Experimental Toxicology of Organophosphates and Carbamates: Pharmacology and Toxicology of Carbamates. Butteworth-Heinemann, UK, 1993.
[2] Tripathi, G.; Kachwaga,N.; Dabi, I. Pestic. Biochem. Physiol. 2010, 96, 30-35. [3] García Río, L.; Hervés, P.; Mejuto, J.C.; Pérez-Juste, J.; Rodriguez-Dafonte, P.; Langmuir, 2000, 16,
9716-9721.
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P51 Effect of mixed crowding media on the diffusion of alpha-chymotrypsin
Isabel Pastor1,2, Eudald Vilaseca1, Sergio Madurga1, Josep Lluís Garcés3, Marta Cascante2 and Francesc Mas1,*
1Departament of Physical Chemistry and Research Institute of Theoretical and Computational Chemistry of the University of Barcelona (IQTCUB), Barcelona (Spain)
2Department of Biochemistry and Molecular Biology and IDIBAPS, University of Barcelona (UB), Barcelona (Spain,)
3Departament of Chemistry and AGROTECNIO. Universitat de Lleida (Spain) *[email protected]
The interior of the living cell is highly concentrated and structured with molecules having different shapes and sizes. While a single species of macromolecules of cellular environments may not be concentrated, the total volume occupied by all macromolecules can constitute up to 40% of its total mass [1]. The high concentration of macromolecules in intracellular environments results into non-specific interactions (macromolecular crowding), which have a great influence on the kinetics and thermodynamics of possible reactions that occur in these systems, e.g. diffusion processes and reaction kinetics [2]. Quantitatively, macromolecular crowding reduces the diffusion coefficient as compared to aqueous solutions, and qualitatively, diffusional motion could be changed toward anomalous diffusion, this mean time dependent diffusion [3-4]. Usually, studies of how macromolecular crowding affects protein´s diffusion are carrying on in homogeneous in vitro media, thus mean that only one size of crowder agent is present by experiment4. However, as it was explained before, the cytoplasm is composed by a large number of different species of macromolecules, we think that is important to carry on a study in heterogeneous crowding media composed by crowded agents with different sizes. In this work we study the diffusion of a model protein (alpha-chymotrypsin) in in vitro mixed crowded solution using three type of Dextran molecules as crowder agents [5].
Acknowledgements: The research leading to these results has received funding from the Spanish Ministry of Education and Science (Projects CTM2009-14612 and CTM2012-39183), and from Generalitat de Catalunya” (2009SGR00465 and XRQTC). IP thanks the Juan de la Cierva Programo f the Spanish Ministry of Science.
[1] Ellis R., J. Trends Biochem. Sci., 26 (2001) 597-604; Hall D. and Minton A.P., Biochim. Biophys. Acta, 2003, 1649, 127; Minton A.P., J. Biol. Chem., 2001, 276, 10577.
[2] Zimmerman S. B. and Minton A. P., Annu. Rev. Biophys Biomol. Struct., 1993, 22, 27; Echevería, C. et al., J. Phys. Codens. Matter, 2007, 19, 065146; Zhou, H.X. et al., Annu. Rev. Biophys., 2008, 37, 375.
[3] Weiss M. et al. Biophys J. 2004, 87, 3518; Saxton M.J., Biophys. J., 2008, 94, 760.; Isvoran, A. et al., Rev. Rom. Chem., 2008, 53, 415; Vilaseca, E. et al., PCCP, 2011, 13, 7396.
[4] Banks D.S. and Frandin C. Biophys. J. 2005, 89, 2960; Pastor, I. et al., J Phys. Chem B, 2010, 114, 4028; Erratum, ibib, 2010, 114, 12182.
[5] Pastor, I. et al., PCCP, 2013 (in press).
SOFT COLLOIDS. SOFT NANOTECHNOLOGY. BIOINSPIRED SYSTEMS 196
P52 Stability of the polymer layers formed by the layer-by-layer method
R. Perea1, M. M. Ramos-Tejada1*, K. Rudzka2 and A. V. Delgado2
1University of Jaén, Department of Physics, 23071 Jaén, Spain. 2University of Granada, Faculty of Science, Department of Applied Physics, 18071 Granada, Spain
There are numerous studies about the preparation of composite particles consisting of cores covered with shells of different chemical composition. Since the properties of such particles (magnetic, optical, electric, adsorptive, etc.) can be altered by appropriate coatings, they may be useful in many applications. The layer-by-layer, LbL, method is an interesting and versatile method to construct coated particles. The technique consists in a nanoscale coating of colloid particles with multiple layers of various kinds, utilizing electrostatic interactions for the buildup of the layers [1-4]. Usually, in the LbL colloid coating method, a polyelectrolyte solution of concentration sufficient to cause adsorption saturation is added to a colloidal suspension. The key point is that the first added polymer bears an opposite charge to that on the core, thereby utilizing electrostatics for adsorption. Hence, when the polymer layer is adsorbed the charge on the surface of the particles is reversed, which aids in the deposition of subsequent layers of a wide range of oppositely charged components. In this work, magnetite cores have been coated with several polymer layers (polyethyleneimine, poly(styrenesulfonate) and poly(diallyldimethylammonium chloride)) using the LbL technique. The stability of the layers with time has been monitorized by zeta potential measurements. We have found that when magnetite is covered with a polymer monolayer the stability of the layer is low, and within a few days an important desorption of the polymer was observed. The multilayer formation improves the stability of the coating although polymer desorption is observed on samples after 20 days.
Acknowledgements: Financial support by Junta de Andalucía, Spain (Project PE2008-FQM3993) and Spanish Ministry of Science and Innovation (FIS2010-19493) is greatly acknowledged.
[1] Caruso, F., Top Curr. Chem., 2003, 227, 145-168. [2] Chen, T.; Somasundaran, P., J. Am. Ceram. Soc., 1998, 81, 140-144. [3] Dokoutchaev, A.; James, J. T.; Koene, S. C.; Pathak, S.; Prakash, G.; Thompson, M. E., Chem.
Mater.,1999, 11, 2389-2399. [4] Keller, S. W.; Johnson, S. A.; Brigham, E. S.; Yonemoto, E. H.; Mallouk, T. E., J. Am. Chem. Soc.,
1995, 117, 12879-12880.
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P53 Ostwald ripening inhibition of concentrated limonene emulsions
L. M. Pérez-Mosqueda1, P. Ramírez1,* and J. Muñoz1
1Departamento de Ingeniería Química, Facultad de Química. Universidad de Sevilla, P. García González 1, 41012 Sevilla, Spain.
Limonene emulsions stabilized by Pluronic P9400 are destabilized by both, Ostwald ripening and creaming. The former is more pronounced in concentrated emulsions ( =50%) and both destabilization processes increase with surfactant concentration in the range 3%-5% (w/w) where monomodal submicron emulsions are obtained (d3,2 ~ 0.8 m, Uniformity ~ 0.35).
In the present work, we focus on the development of a formulation that inhibits Ostwald ripening for concentrated limonene emulsions ( = 50%) containing 3% (w/w) Pluronic P9400 as emulsifier. As it is well-known this destabilization process can be delayed and eventually stopped by adding a water insoluble compound to the oil phase [1,2].
Three different additives (tetradecane, silicone oil and rosin gum) have been added to limonene in order to study their properties as Ostwald ripening inhibitors. The droplet size growth in the presence of each of these chemicals was monitored by means of laser diffraction (Mastersizer X, Malvern).
The influence of additive concentration was also studied. It is shown that a low concentration of tetradecane and silicone oil (ca. 2% (w/w)) drastically reduced the Ostwald ripening rate. Nevertheless, a much higher concentration of rosin gum was needed to prevent droplet growth (>15%(w/w)).
Although emulsions containing tetradecane and silicone oil maintained the same droplet size, they became destabilized by creaming. However, the addition of rosin gum at concentrations higher than 15% (w/w) resulted in stable limonene emulsions avoiding creaming separation. This may be due to the combination of two cooperative effects. Rosin gum increases the density of the disperse phase, hence the creaming driving force is diminished and on top of that the droplet size turns out to be lower (d3,2 ~ 0.5 m, Uniformity~ 0.35 ), which will also prevent creaming from occurring.
Acknowledgements: The financial support received (Project CTQ2011-27371) from the Spanish Ministerio de Economía y Competitividad (MINECO) and from the European Commission (FEDER Programme) is kindly acknowledged. L. M. Pérez-Mosqueda also acknowledges the Universidad de Sevilla for its financial support (Beca PIF IV Plan Propio de Investigación).
[1] Schmitt, V.; Cattelet, C.; Leal-Calderon, F. Langmuir, 2004, 20, 46-52 [2] Taisne, L.; Cabane, B. Langmuir, 1998, 14, 4744-4752
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P54 Studies on the colloidal stability of F-DPPC and DPPC liposomes. The influence
of Ca2+ and the interdigited bilayer on the aggregation process Gerardo Prieto1,*, Paula Toimil1, Rocío Daviña1 and Félix Sarmiento1
1Biophysics and Interfaces Group, Department of Applied Physics, Faculty of Physics, University of Santiago de Compostela, E-15782 Santiago de Compostela, Spain.
Fluorinated phospholipids present a remarkable biological interest due to the high sensitivity of fluorine-19, which enables them to be identified in membranes. The use of liposomes composed by fluorinated phospholipids as vehicles for drug delivery has been subject of an increasing number of research in recent years. Previous works have demonstrated that liposomes partially or totally formed by phospholipids containing fluorinated tails modify the thermotropic phase behavior of the bilayer, diminish the membrane permeability and increase the coloidal stability of the such systems [1,2]. In this work, the aggregation of unilamellar liposomes composed by 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and 1-palmitoyl-2-[16-fluoropalmitoyl]-sn-glycero-3-phosphocholine (F-DPPC), in presence of calcium ions at temperatures below and above the phase transition of both phosphlipids, has been studied in order to analyze the influence of the physical state of the bilayer on the aggregation process. Changes in the size and polydispersity, obtained by dynamic light scattering were used to calculate the critical aggregation concentrations (c.a.c.) of Ca2+ at which the aggregation of DPPC or F-DPPC was produced. The results showed different behaviours: at 25 ºC, when the liposomal bilayers are in gel phase and F-DPPC bilayers are interdigited, DPPC liposomes are more resistant to aggregation induced by Ca2+ than F-DPPC liposomes. However, at 60 ºC, when liposomes are in liquid-crystalline phase and both bilayers have the same conformation, this difference disappears and c.a.c coincides for the two types of liposomes. These results also indicate that c.a.c for the two types of liposomes increases with temperature, suggesting the temperature as a factor to prevent the liposome aggregation. To compare the experimental results with the theoretical values obtained by application of DLVO theory, electrophoretic mobilities for liposome dispersions have been measured.
Figure caption: Stability of F-DPPC liposomes in presence of Ca2+ as a function of temperature (Tc: transition T)
Acknowledgements: This work was supported by the Spanish “Ministerio de Economía y Competitividad” (Project MAT2011-26330), by the “European Regional Development Fund (ERDF)” and by “Xunta de Galicia” (Project INCITE08PXIB206030PR). [1] Toimil, P.; Prieto, G.; Miñones, J. Jr.; Sarmiento, F., Phys. Chem. Chem. Phys. 2010, 12, 13323-13332. [2] Smith, E. A.; van Gorkum, C. M.; Dea, P. K., Biophys. Chem. 2010, 147, 20-27.
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P55 Microfluidic synthesis of silicone capsules for encapsulation and release
applications N. Vilanova1,*, C. Rodríguez-Abreu2, A. Fernández-Nieves3, C. Solans1
1Institute for Advanced Chemistry of Catalonia, Consejo Superior de Investigaciones Científicas (IQAC-CSIC), CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Barcelona, Spain
2International Iberian Nanotechnology Laboratory (INL), Braga, Portugal 3School of Physics, Georgia Institute of Technology, Atlanta, USA
The production of capsules is attracting a great interest due to their potential applications in drug delivery. To regulate the release of the drug, it is critical to control the morphology and polydispersity of the capsules; hence the choice of the strategy to produce them is crucial. Most of the strategies rely on the use of double emulsions as templates, which can be produced by numerous methods. Particularly, the use of microfluidic devices to produce double emulsions has emerged as a useful tool, inasmuch as they enable an accurate control over the morphology and composition of the emulsions [1]. Although microfluidics have met success in the preparation of capsules with a wide range of interesting materials [2], the production of silicone capsules is not so extended despite their attractive properties such as thermal and chemical stability, high permeability to solvents or biocompatibility [3]. Their limited availability mainly arises from the high viscosity of the most common silicone precursors, which hampers their manipulation within the microfluidic device. Here, we report on the production of silicone capsules by means of microfluidic devices (Fig.a) using double W/O/W emulsions as templates, having a low-viscosity silicone precursor as the intermediate phase. Stable and monodisperse double W/O/W emulsions, were successfully produced (Fig.b). The size of the droplets was precisely controlled from 60 to 200 μm by varying the diameter of the capillary tips. The thickness of the shell was also tuned from 2 to 22 μm by adjusting the flow rates of each of the phases. Silicone capsules were obtained by hardening the intermediate oil phase through a thermal-induced crosslinking reaction, resulting in the desired monodisperse silicone capsules, hence confirming the templating effect (Fig.c). Moreover, it was also observed that the mechanical behavior of capsules could be regulated by varying the size and the shell thickness of the capsules, as well as the elastic modulus of the silicone network. Besides, it was also possible to encapsulate a hydrophilic molecule within the capsules. Its release was also studied as a function of the shell thickness, the temperature and the type of receptor solvent. In all cases the hydrophilic molecule was released in a controlled manner.
Figure caption: Optical micrographs of a) the device used to produce the multiple emulsions, b) silicone double emulsion drops and c) the corresponding silicone capsules.
[1] Utada, A. S., Lorenceau, E., Link, D. R., Kaplan, P. D., Stone, H. A., Weitz, D. A., Science 2005, 308, 537-541 [2] Duncanson, W. J., Lin, T., Abate, A. R., Seiffert, S., Shah, R. K., Weitz, D. A., Lab Chip 2012, 12, 2135-2145 [3] Mark, J. E., Allcock, H. R., West, R. Inorganic Polymers, Second Edition, Oxford University Press, New York,
2005
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P56 Contact angle hysteresis of commercially pure titanium surfaces functionalized
with organophosphonates D. Blasco-Avellaneda, A. Y. Sánchez-Treviño, M. A. Rodríguez-Valverde*,
M. A. Cabrerizo-Vílchez
Dept. of Applied Physics, University of Granada, Campus of Fuentenueva, E-18071 Granada (Spain) *[email protected]
The implementation of soft matter physics in the design of biomimetic materials is an exciting and emerging field in material sciences. The chemical tailoring of titanium surfaces with self-assembled monolayers of organophosphonates enables to reach an optimal range of biofunctions in a biomaterial [1]. The functionalized surface with this strategy is mechanically strong and chemically stable. Wettability of a solid surface is sensitive to its chemical composition, thus contact angle measurements enable to reveal the quality of a chemically-modified surface. However, there are a range of observable contact angles rather than a unique value due to contact angle hysteresis. The maximum contact angle (advancing angle) of a solid-liquid system is usually related with the low-surface energy domains, whereas the minimum contact angle (receding angle) with the high-surface energy domains. In this work, we used commercially pure titanium devoted to dental implant and three organophosphonate molecules with different terminal groups: methyl, phosphonate and carboxyl groups. Machined titanium surfaces were ultrapolished and next, functionalized as the protocol reported recently [2]. Contact angle measurements were conducted at room temperature with MilliQ water using the tilting plate method. The tilting plate provided values of contact angle hysteresis. We found that the advancing contact angle of the chemically-modified titanium surfaces reflected the twisted hydrocarbon chains, the bare regions of titanium (oxidized) or the methyl terminal group, accordingly. Instead, the receding contact angle provided information about the hydrophilic terminal groups (phosphonate and carboxyl). These results were further validated by AFM, XPS and SEM (backscattered electron imaging).
Acknowledgements: This study was supported by the Ministry of Science and Innovation (Project MAT-2010-14800) and by the Junta of Andalucía (Projects P08-FQM-4325 and P09-FQM-4698). Thanks to J.A. Martín- Pérez for the cutting and polishing of the titanium samples.
[1] Paz, Y. Self-assembled monolayers and titanium dioxide: From surface patterning to potential applications, Beilstein J. Nanothechnol. 2011, 2, 845-861.
[2] M. A. Fernández-Rodríguez, M. A. Rodríguez-Valverde and M. A. Cabrerizo-Vílchez. Selective desorption of organophosphonates on chemically functionalized titanium by Direct Laser Patterning. Colloids Surf. A: Physicochem. Eng. Aspects 2013, doi:10.1016/j.colsurfa.2013.02.047
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P57 Self-assembled 2D arrays of Au nanoparticles
Juan J. Giner-Casares1,*, Luis Liz-Marzán1,2
1Bionanoplasmonics Laboratory, CIC biomaGUNE, Paseo de Miramón 182, 20009 Donostia, San Sebastián, Spain.
2Ikerbasque, Basque Foundation for Science, 48011 Bilbao, Spain. *[email protected]
The self-assembly of metallic plasmonic nanoparticles (NPs) through the “bottom-up” approach is undoubtedly a highly precise tool for obtaining rationally designed assembly of the NPs into more complex structures. Moreover, such self-organized plasmonic structures can be effectively integrated into microscale devices [1].
Interfacial self-assembly of metallic nanoparticles at the air/liquid interface offers the following features: a) experimentally simple, b) no required template, c) scalable to large areas, d) fine control on the interparticle distance, e) extended order of particle positions and gaps, and f) applicable to different sizes, shapes, and chemical nature of NPs. The interfacial spontaneous self-assembly basically consists on the adsorption of NPs at the air/liquid interface and subsequent transfer to a solid substrate by means of the Langmuir-Schaeffer method, i.e. lifting of the substrate parallel to the air/liquid interface [2]. In this work, a series of hydrophobic nanoparticles have been synthesized for their controlled self-assembly onto solid substrates, see Figure.
Figure caption: Normalized UV-vis spectra of hydrophobic nanoparticles in hexane solution (left spectrum) and on the subsequent transference to a solid glass support (right spectrum).
Acknowledgements: This work was supported by the ERC Advanced Grant PLASMAQUO (267867)
[1] Alvarez-Puebla, R. A.; Liz-Marzán, L. M., Chem. Soc. Rev. 2012, 41, 43. [2] Sánchez-Iglesias, A.; Grzelczak, M.; Pérez-Juste, J.; Liz-Marzán, L. M., Angew. Chem. Int. Ed.
2010, 49, 9985.
SURFACES AND INTERFACES 202
P58 Lipid specificity for the interaction of a novel antimicrobial peptide sp85 with
model membranes A. Grau-Campistany1,2, M. Pujol1, F. Rabanal2, Y. Cajal1,*
1Department of Physical Chemistry, Faculty of Pharmacy, Avn. Joan XXIII s/n, 08028 Barcelona, Spain. 2Department of Organic Chemistry, Faculty of Chemistry, Martí i Franquès 1, 08028 Barcelona, Spain.
Sp85 is a synthetic cationic lipopeptide derived from polymyxin B that shows good activity against Gram negative and Gram positive bacteria. We examined the interaction of sp85 with negatively charged Langmuir monolayers of POPG and POPE/POPG (6:4), as models of the Gram positive and Gram negative bacterial cytoplasmic membrane. Kinetics of insertion at constant area show good levels of peptide binding even at high surface pressures in the range of the membrane equivalence pressure. Surface pressure isotherms of mixed lipid/peptide systems are consistent with non-ideal mixing behavior, with negative values of excess free energy. Sp85 binding to unilamelar lipid vesicles of the same compositions results in leakage of aqueous contents and lipid mixing. Results are consistent with a mode of action based on the disruption of the bacterial membrane. Figure caption: Surface pressure-area isotherms of mixed lipid-sp85 monolayers at various peptide mole
fractions.
Acknowledgements: Funding has been provided by MICINN (CTQ2008-06200), Generalitat de Catalunya (VAL-TEC 08-1-0016, ACC10), and Fundació Bosch i Gimpera (UB).
[1] Rabanal, F., Rodríguez, M., Garcia, M., Cajal, Y. Patent 2011, WO2011110716 [2] Clausell, A., Busquets, M. A., Alsina, M. A., Cajal, Y. Biopolymers 2004, 75, 480-490. [3] Clausell, A., Garcia-Subirats, M., Pujol, M., Busquets, M. A., Rabanal, F., Cajal, Y. J. Phys. Chem.
B, 2007, 111, 551-563.
POPG
0 50 100 150 200 2500
10
20
30
40
50
Xsp85=1.0
Xsp85=0.2Xsp85=0.0
Xsp85=0.4Xsp85=0.5
Xsp85=0.8Xsp85=0.6
Area, Å2/molecule
, mN
/m
POPG/POPE
0 50 100 1500
10
20
30
40
50Xsp85=0.0Xsp85=0.2Xsp85=0.4
Xsp85=0.6Xsp85=0.5
Xsp85=0.8Xsp85=1.0
Area, Å2/molecule
, mN
/m
SURFACES AND INTERFACES 203
P59 Naphthenic bitumen-calcite aggregate wettability at high temperature
F. Guerrero-Barba1,*, J. E. Arellano-Varela2, M. Cabrerizo-Vílchez1, M. A. Rodríguez-Valverde1
1Biocolloid and Fluid Physics Group, Department of Applied Physics, University of Granada, Campus of Fuentenueva, E-18071 Granada, Spain.
2Petróleos de Venezuela S.A., Av. Libertador, Edif. PDVSA, Torre Este La Campiña, La Campiña, Caracas (Venezuela)
In hot asphalt applications, the thermodynamic adhesion between bitumen and aggregate depends on the surface tension of bitumen and the bitumen-aggregate contact angle. Measurement of the physico-chemical bond between bitumen and aggregates should be done at the same temperatures that the asphalt would be produced at the mixing plant (150-190 ºC). This is currently not possible with the conventional equipments. In this work, we designed a new goniometer (contact angle instrument) especially devoted to measure the bitumen-aggregate wettability at high temperature.
Migration of endogenous surfactants of bitumen toward the interface [1] and interface oxidation may be noticeable at high temperatures. We monitored the spreading of heavy naphthenic bitumen, which is greatly active, on polished substrates of calcite as highly reactive aggregate. We measured the bitumen contact angle and surface tension in terms of temperature using the sessile drop method. The surface tension values were validated with the pendant drop method and a high temperature tensiometer.
Figure caption: Bitumen spreading on calcite substrate (25 μl, 10 min, 80º C)
Acknowledgements: This work was supported by the "Ministerio Español de Ciencia e Innovación" (project MAT2011-23339) and the "Junta de Andalucía" (projects P08-FQM-4325 and P09-FQM-4698).
[1] Chaverot P., Cagna Alain, Glita Sylvie, Rondelez Francis, Interfacial Tension of Bitumen�Water Interfaces. Part 1: Influence of Endogenous Surfactants at Acidic pH. Energy & Fuels pp: 790-798.
SURFACES AND INTERFACES 204
P60 Surface tensions and activity coefficients for aqueous solutions of
lauryl ether ethoxylates J. L. López-Cervantes1, J. Gracia-Fadrique1, E. Acosta, E. Calvo2 and A. Amigo2,*
1Facultad de Química, Departamento de Fisicoquímica, U.N.A.M., México, D.F., 04510, Mexico. 2Departamento de Física Aplicada, Facultad de Física, Universidad de Santiago de Compostela, E-
15782, Santiago de Compostela, Spain. *[email protected]
Surface tensions for aqueous solutions of Lauryl ether ethoxylates at the temperature 298.15 K were measured using a Lauda drop volume tensiometer. The non-ionic surfactants analyzed in this work were polyoxyethylene 9 lauryl ether (polidocanol) and polyoxyethylene 4 lauryl ether (brij 30). The surface tension values were used to determine the critical micelle concentrations (CMC) of the surfactant aqueous solutions as well as to calculate the infinite dilution activity coefficient of the surfactant following two different models. The first one combines the first natural nonideal surface equation of state of the Van der Waals type, the Volmer equation ���� � �� ��, and the Gibbs adsorption equation and is based on the application of equilibrium conditions between bulk and surface phases. The second one is a group contribution model that takes into account the mass spectra of the surfactants. The activity coefficient at infinite dilution for linear surfactants is an additive property that can be expressed as the sum of hydrophobic and hydrophilic contributions
�� �� � �� ���� � �� ��� � � ���������� ��
where � represents the number of C-atoms in the hydrocarbon part of the surfactant and � the number of ethylene oxide (EO) units in the molecule. Considering the molecular weight distribution of the surfactants we can conclude
�� �� � ���� �� ���� � �� ��� � � �� ���������
����
� ������
��
where �� represents the probability of finding a molecule with m ethylene oxide units in the surfactant. The Poisson distribution was used to fit the experimental surfactant molecular weight distributions obtained by MALDI-TOF. As an example, Figure shows the MALDI-TOF mass spectrum of polyoxyethylene 4 lauryl ether and the Poisson distribution. Values of �� from group contributions can now be determined by using Eq. [2] and taking into account the presence of C14Em in the surfactant molecular weight distribution. These values coincide well with the experimental ones (from Volmer’s SEOS).
Figure caption: MALDI-TOF mass spectrum of polyoxyethylene
4 lauryl ether and the Poisson distribution.
�
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 170.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
0.16
C12
E4
C14
E4
f m
m
!
7.16 0.08
m
mef
m
SURFACES AND INTERFACES 205
P61 Modulation of film morphology at nanoscale by Dipping, Langmuir-Blodgett
and Langmuir-Schaefer M. D. Merchán*, T. Alejo, and M. M. Velázquez
Departamento de Química Física, Facultad de Ciencias Químicas, Universidad de Salamanca. 37008 Salamanca, Spain.
*[email protected] Dipping, Langmuir-Blodgett (LB) and Langmuir-Schaeffer (LS) have been widely used as
techniques in the preparation of nanomaterials on solids with different purposes. In all cases, the final target is to deposit some material with a high grade of coverage in a thin film, looking forward some direct application. Usually the affinity with the solid is not efficient and the resultant films do not have the desired characteristics. On the other hand, when biomolecules, i.e., proteins, whose biological activity depends on the molecular arrangements, are immobilized on films, the control on the structure and orientation of the surface and the properties of molecules adsorbed on the solid wafers become extremely important [1].
The zwitterionic surfactant 3-[(3-cholamidopropyl)-dimethyl-ammonium]-1-propane sulphonate (CHAPS) is widely used in biochemical applications such as protein solubilization or disaggregation, and as eluting agent in separation processes to provide selectivity. Recently, the zwitterionic surfactant CHAPS has been proposed as component of biosensors [2]. One important characteristic of the biosensors is that the analyte molecules have to be immobilized onto solids to react with the sensing component; therefore thinner films with a well-defined structure must be obtained to host the analyte molecules. In a previous work [3] we present a comparison by means of Atomic Force Microscopy, Optical microscopy and Micro-Raman Spectroscopy between Dipping and LS techniques in the deposition of CHAPS and Polyethylene imine polymer (PEI)/CHAPS mixtures onto mica. The hydrodynamic flow of water after its evaporation induces the formation of ring based structures not available to fabricate biosensors. These patterns are dominating when materials are transferred from the solution onto mica by Dipping. In contrast, the LS technique provides spherical aggregates and dense and ordered films.
Self-assembly is established as a very interesting technique in the preparation of many different types of nanomaterials. Specifically, thin films of soft matter can provide templates for the fabrication of devices based on QDs in an attempt to achieve sufficiently dispersed nanomaterials in which the agglomeration of nanoparticles was minimized [4]. In a second part, we have studied the ability of poly(octadecene-co-maleic anhydride) (PMAO) and a Gemini surfactant [C18H37 (CH3)2 N+ Br
– -(CH2)2- N+ Br – (CH3)2 C18H37] (18-2-18) to assist in the self-assembly process of CdSe quantum dots (QDs) at the air-water interface. Results show that, while QD agglomeration is generally inhibited by the addition of these components to the Langmuir monolayer of QDs, structure of the film transferred onto mica by the Langmuir-Blodgett method is strongly affected by the dewetting process. Nucleation-and-growth of holes and spinodal-like dewetting [5] were respectively observed in the presence of either PMAO or 18-2-18. When PMAO/18-2-18 mixtures were used, both mechanisms were allowed; nevertheless, even in films prepared with mixtures of low polymer contents, characteristic morphology from the polymer dewetting route prevailed. Acknowledgements: The authors thank financial support from ERDF and MEC (MAT 2010/19727). T.A. wishes to thank European Social Fund and Junta de Castilla y León for the FPI grant. The authors want to thank especially to Drs J.A. Pérez-Hernández for the AFM measurements and C.L.P.U. (University of Salamanca) for the AFM facility. We thank to Drs Cirera and Claramunt (University of Barcelona) for the Micro-Raman facility. [1] Girart, A. P.; Godoy, S.; Blum, L. J. Adv. Colloid Interf. Sci. 2005, 116, 205. [2] Lee, T.; El-Said, W. A.; Min, J. ; Oh, B. K.; Choi, J. W. Ultramicroscopy 2010, 110, 712. [3] S. Heisig, M.D. Merchán, M.M. Velázquez, J. Colloid Sci. Biotechnol. 2012, 1, 33-41. [4] Langner, K. M.; Sevink, G. J. A. Soft Matter 2012, 8, 5102-5118. [5] Gentili, D., et al Chem. Soc. Rev. 2012, 41, 4430-4443.
SURFACES AND INTERFACES 206
P62 Implication of a peptide sequence from GB virus C in the inhibition of HIV
fusion peptide M. Muñoz1,2,3,*, J. Prat1,2,3, M. A. Busquets1,2,3, M. Pujol1,2,3, A. Ortiz1,2,3, O. Domènech1,2,
M. A. Alsina1,2,3, V. Girona1,2,3 1Physical Chemistry Department. Faculty of Pharmacy. University of Barcelona. Avda Joan XXIII, s/n.
08028 Barcelona. Catalonia. Spain. 2Institute of Nanoscience and Nanotechnology (IN2UB), University of Barcelona, Martí i Franquès 1,
08028 Barcelona, Spain. 3Associated Unit to the CSIC Peptides and proteins, physicochemical properties.
GB virus C (GBV-C) (formerly known as hepatitis G virus) has recently gained special attention due to its potential role in the inhibition of AIDS progression [1]. In the present study we attempted to find the relationship between the physicochemical properties of the peptide sequence of GBV-C E2 (153-170) (SDRDTVVELSEWGVPCAT) (P45) and the in vivo results [2]. The peptide shows low surface activity when injected into a buffered saline subphase pH:7.4 and little penetration into 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC)/ 1,2-dimyristoyl-sn-glycero-3-phospho-L-serine (sodium salt) (3:2) lipid monolayers (Figure 1, left). P45 doesn’t affect significantly, FI-HIV penetration into DMPC/DMPS monolayers [3]. However, fluorescence anisotropy indicates that the peptide inhibits FP-HIV activity in the hydrophobic core of the bilayer (Figure, right). Atomic force microscopy (AFM) has confirmed the anisotropy results.
Figure caption: Left, penetration kinetics of DMPC/DMPS (3:2 molar ratio) lipid monolayers of P45, FP-HIV and the mixture FP-HIV/P45 (1:2 molar ratio). Right, anisotropy values of 1,6-Diphenyl-1,3,5-Hexatriene
(DPH) fluorescent probe in bilayers of large unilamellar vesicles.
Acknowledgements: This work was supported by Grants CTQ2012-37589-C02-02 from the Ministerio de Economía y Competitividad and 2009 SGR 560 from the Generalitat de Catalunya.
[1] Zhang, W.; Chaloner, K.; Tillmann, H. L.; Williams, C. F.; Stapleton, J. T. HIV Medicine 2006, 7, 173-180 [2] Herrera, E.; Tenckhoff, S.; Gómara, M. J.; Galatola, R.; Bleda, M. J.; Gil, C.; Ercilla, G.; Gatell, J. M.;
Tillmann, H. L.; Haro, I. J. Med. Chem., 2010, 53, 6054-6063. [3] Haro, I.; Gómara , M. J.; Galatola, R.; Domènech, O; Prat, J.; Girona, V.; Busquets, M. A. Biochim. Biophya.
Acta 2011, 1808, 1567–1573.
� DMPC/DMPS (3/2)
0 10 20 30 400
5
10
15
20
p45FP-HIV-p45FP-HIV
Initial surface pressure/mNm-1
Pres
sure
incr
ease/m
Nm
-1
DMPC/DMPS (3/2)DPH
10 15 20 25 30 35 400.0
0.1
0.2
0.3
0.4
0.5ControlFP-HIVFP-HIV/P45P45
Temperature/oC
Anis
otro
py
SURFACES AND INTERFACES 207
P63 Study of the Behavior of Poly(NIPAM) Microgels under Ionic Specific
Conditions: Electrokinetic and AFM measures Leonor Pérez-Fuentes1,*, Carlos Drummond2 and Delfi Bastos-González1
1Biocolloid and Fluid Physics Group, Department of Applied Physics, University of Granada, Granada 18071 (Spain)
2CNRS, Centre de Recherche Paul Pascal (CRPP), Bordeaux (France) *[email protected]
Ionic specificity, also known as Hofmeister effects, has been studied since Hofmeister discovered them in 1888 [1]. These effects are connected with the ability of different ions to modify interfaces properties. In spite of many works about this issue, there is no a theory that provides a complete explanation of the origin of Hofmeister effects. According to previous researches [2,3], hydrophobic or hydrophilic character of surfaces is crucial to explain ionic specificity.
In order to deepen in the origin of Hofmeister phenomena and their connection with reversal charge and hydrophobic effect [4], we have chosen a very sensitive system to ionic medium conditions, such as poly(NIPAM) microgels [5]. These microgels are formed by polymer poly(N-isopropyl acrylamide), with extraordinary properties of solvency, which are highly dependent on physicochemical conditions such as temperature, salt concentration and pH. Therefore, microgels experiment a volume phase transition caused by temperature change, from swollen state (hydrophilic character) to collapsed state (hydrophobic character). In particular, for poly(NIPAM) the lower critical solution temperature (TLCS) is about 32 ºC. This TLCS is very sensitive to ionic specific effects.
We have performed an experimental study with different hydrophobic or chaotropes anions (tetraphenylborate, tetraphenylarsonium and thiocyanate) and two poly(NIPAM) microgels synthesized in our labs, one negative and one positively charged. Experiments were carried out with nano-zeta and AFM devices. AFM in liquid environment is an excellent tool to study in-situ the properties of responsive surfaces [6]. We have studied, with this tool, swelling-to-collapse transition of the cationic and anionic poly(NIPAM) microgels adsorbed on inverse-charged-substrate. We observed that swelling process and adsorption properties of microgels are modified by the ionic environment. On the other hand, we also measured electrophoretic mobility with the different ions under identical conditions that in AFM studies. The combination of both techniques has been found very useful in order to explain the adsorption of chaotropes ions to the poly(NIPAM) interface and hence to improve the understanding of ionic specificity in colloidal systems.
Acknowledgements: The authors acknowledge the financial support from projects MAT2009-13155-C04-02, MAT2012-3670-C04-02 (Ministerio de Educación y Cultura (Spain)), P10-CTS-6270 (Junta de Andalucía) and CEIBioTic 20F12/16.
[1] Hofmeister, F., Arch.Pathol. 1888, 24, 247. [2] López-León, T.; Santander-Ortega, M. J.; Ortega-Vinuesa, J. L.; Bastos-González, D., J. Phys. Chem. C.
2008, 112, 16060. [3] Peula-García, J. M.; Ortega-Vinuesa, J. L.; Bastos-González, D., J. Phys. Chem. C. 2010, 114, 11133. [4] Calero, C.; Faraudo, J.; Bastos-González, D., J. Am. Chem. Soc. 2011, 133, 15025. [5] López-León, T.; Elaïssari, A.; Ortega-Vinuesa, J. L.; Bastos-González, D., ChemPhysChem. 2007, 8, 148. [6] Bousquet, A.; Ibarboure, E.; Drummond, C.; Labrugère, C.; Papon, E.; Rodriguez-Hernandez, J.,
Macromolecules. 2008, Vol. 41, No. 4, 1053.
SURFACES AND INTERFACES 208
P64 Properties of chitosan-insulin complexes obtained by an alkylation reaction on
chitosan Emmanuel Robles1, Josué Juárez3,*, Manuel Alatorre-Meda4, María. G. Burboa2,
Pablo Taboada4, Víctor Mosquera4, Miguel A. Valdez3 1Departamento de Investigación en Polímeros y Materiales,
2Departamento de Investigaciones Científicas y Tecnológicas, 3Departamento de Física, Universidad de Sonora, Rosales y Transversal,
83000 Hermosillo, Sonora, México 4Departamento de Física de la Materia Condensada, Facultad de Física,
Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain *[email protected]
Recently we have investigated the influence of hydrophobization of chitosan on the in vivo release insulin of insulin-chitosan nanopartilces [1]. In this work, we investigate the influence of chitosan hydrophobization on the formation, thermodynamic and surface tension properties of insulin-chitosan complexes. We use an alkylation procedure to insert 12 carbon chains along the chitosan macromolecule with a final 5, 10 and 50 % substitution degree. Nuclear magnetic resonance (NMR) and infrared spectroscopies (IR) were used to evaluate the success and extent of the hydrophobization procedure. The size of bare polymer and polymer-insulin complexes were evaluated by dynamic light scattering (DLS). DLS data demonstrated that complexes made with hydrophobized chitosans possess smaller sizes than the ones obtained with unmodified chitosan. Isothermal titration calorimetry (ITC) was used to determine the type and extent of the existing interactions between the different constituting components of insulin-hydrophobized chitosan complexes. By surface tension, diffusion coefficients at the air-water interface and ITC experiments on different insulin/chitosan proportions we demonstrate that around 34, 25, 25 and 60 insulin molecules saturate 0 %, 5 %, 10 % and 50 % hydrophobized chitosans, respectively. Surface tension experiments at the air-water interface of insulin-chitosans complexes demonstrate that insulin molecules on unmodified chitosan increases hydrophobicity, which demonstrates mainly electrostatic interaction, on the contrary insulin-hydrophobized chitosans interaction lowers the hydrophobicity due to the insulin alkyl chains interaction.
[1] Effects of the hydrophobization on chitosan-insulin nanoparticles obtained by an alkylation reaction on chitosan. Robles, E.; Villar, E.; Alatorre-Meda, M; Burboa, M. G.; Valdez, M. A.; Taboada, P.; Mosquera, V. J. Appl. Polym. Sci., 2012, DOI: 10.1002/APP.38870
SURFACES AND INTERFACES 209
P65 From 2D to 3D at the Air/Water Interface: The Self-Aggregation of the Acridine
Dye in Mixed Monolayers Carlos Rubia-Payá1,*, Eugenio Jimenez-Millán1, Juan J. Giner-Casares1, Gerald Brezesinski2,
María T. Martín-Romero1, and Luis Camacho1. 1Department of Physical Chemistry and Applied Thermodynamics, University of Córdoba, Campus de
Rabanales, Edificio Marie Curie, Córdoba, Spain E-14014. 2Department of Interfaces, Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14476,
Germany *[email protected]
The formation of well-defined supramolecular structures in the nanoscopic scale is a fundamental step in nanotechnology. The fine control of the layer-by-layer growth of the supramolecular assemblies at interfaces is most desirable. The collapse of a mixed monolayer composed of two surfactants in equimolar ratio: the organic dye N-10-dodecyl acridine (DAO) and stearic acid (SA) is analyzed herein. The collapse process of the DAO:SA mixed monolayer has been monitored using surface pressuremolecular area (�-A), surface potential isotherms, UV-visible reflection spectroscopy, Polarization-Modulated Infrared Reflection-Absorption Spectroscopy (PM-IRRAS), Brewster Angle Microscopy (BAM), and synchrotron-based in situ X-ray Reflectivity (XRR) measurements. The collapse of the DAO:SA mixed monolayer leads to an ordered trilayer. The growth of anisotropic 2D domains of micrometric size is observed during the formation of the trilayer, relating to the ordering of the acridine polar headgroups. The trilayer is organized with the first and third monolayers displaying the polar headgroups pointing to the aqueous subphase, whereas the intermediate layer display the polar headgroups pointing to the air. The trilayer is stabilized by the strong self-aggregation acridine dye group of the DAO molecule. The controlled transition from a monolayer to a trilayer described herein is proposed as a model for further interfacial supramolecular structures of tunable thickness comprising organic dyes.
Figure caption: BAM image of Hexagonal domains, and Schematic model of the trilayer formed during the collapse process. DAO molecules are red colored, and SA molecules are blue colored.
Acknowledgements: Juan J. Giner-Casares acknowledges the Alexander von Humboldt foundation for a postdoctoral grant. We thank HASYLAB at DESY, Hamburg, Germany, for beamtime and Dr. Bernd Struth for excellentsupport and assistance. This work was supported by the Max Planck Society. The authors thank the Spanish CICYT for financial support of this research in the framework of Project CTQ2010-17481 and also thank the Junta de Andalucía (CICyE) for special financial support P08-FQM-4011 and P10-FQM-6703.
[1] Pérez-Morales, M.; Pedrosa, J. M.; Martín-Romero, M. T.; Möbius, D.; Camacho, L. J. Phys. Chem. B 2004, 108, 4457-4465
[2] Giner-Casares, J. J.; de Miguel, G.; Perez-Morales, M.; Martin-Romero, M. T.; Camacho, L.; Muñoz, E., J. Phys. Chem. C 2009, 113, 5711-5720.
SURFACES AND INTERFACES 210
P66 In-situ monitoring of biomimetic hydroxyapatite growth on functionalized
titanium surfaces: An AFM study A. Y. Sánchez-Treviño*, M. A. Fernandez-Rodríguez, M. A. Rodríguez-Valverde and
M. A. Cabrerizo-Vílchez
Dpto. Física Aplicada, Facultad de Ciencias, Campus Fuentenueva s/n, Universidad de Granada, E-18071 Granada, Spain.
In dental implantology, a satisfactory short-term response of the implants may allow for a rapid healing and earlier loading. Biomimetic strategies intend to accelerate the bone growth on implant surfaces. A promising approach (simple and cost-effective) is the growth of artificial hydroxyapatite (HA) on chemically modified titanium surfaces immersed in a simulated body fluid (SBF) upon physiological conditions [1-3]. Although the biomimetic coating on titanium implants must reach certain mechanical properties with long times of SBF incubation, the nucleation and the subsequent growth of bone-like apatite on the titanium surface begin rapidly. The final properties of the biomimetic HA layer might be partly dictated by the first underlying layer. In this study, we continuously monitored the early kinetics (up to 8 h) of HA growth on a titanium surface with Atomic Force Microscopy (AFM, Nanoscope IV, Veeco). For this study, we used ultra-polished metallic titanium surfaces (ASTM grade II) activated separately with two molecules of organophosphonates (phosphonate and carboxyl functional groups). A previous nucleation of nascent calcium phosphate, deposited by a fast precipitation method [4], was performed to reduce the time of biomimetic HA growth. Further, we concentrated the SBF up to 1.5 times regarding the standard recipe [5]. The growth of biomimetic coating was conducted inside the AFM liquid cell, filled with SBF and maintained at 37ºC. Each surface was imaged in tapping mode using standard silicon cantilevers (Veeco probes, nominal spring constant 20-80 N/m), refreshing the SBF solution each 2 h. The results show that the well-known globular morphology of apatite layers was revealed in 7 h, being much more uniform in height over the titanium surfaces modified with organophosphonates than over the unmodified (hydroxylated) surfaces (peak-to-valley distance = 1014 nm).
Figure caption: AFM height images of HA coatings developed on titanium surfaces after 7 h: (a) unmodified (hydroxylated) surface and (b) carboxyl-terminated surface.
Acknowledgements: This study was supported by the Ministry of Science and Innovation (Project MAT-2010-14800) and by the Junta of Andalucía (Projects P08-FQM-4325 and P09-FQM-4698). Thanks to J.A. Martín- Pérez for the cutting and polishing of the titanium samples.
[1] Dapeng, L. Hydroxyapatite formed on titanium via a self-assembled monolayer and its in-vitro behaviour. Thesis (M. Eng. Sc.) University of Adelaide, School of Chemical Engineering, 2005.
[2] Xia, W.; Lindahl, C.; Lausmaa, J.; Engqvist, H. Biomimetic Hydroxyapatite Deposition on Titanium Oxide Surfaces for Biomedical Application. Advances in Biomimetics. InTech, 2011.
[3] Wu, J.; Hirata; I.; Zhao, X.; Gao, B.; Okazaki, M.; Kato, K., J. Biomed. Mater. Res. Part A 2013. [4] Koichi, K.; Yoshihiro, E.; Yoshito, I., J. Biomed. Mater. Res. 1996, 32, 687-691. [5] Jalota, S.; Bhaduri, S. B.; Tas, A. C., J. Mater. Sci.: Mater Med. 2006, 17, 697.
MODELING AND SIMULATIONS 211
P67 Using artificial intelligence based tools for predicting the CMC
of non-ionic surfactants G. Astray1,2,*, O. A. Moldes1, M. A. Iglesias-Otero1 and J. C. Mejuto1
1Department of Physical Chemistry, Faculty of Sciences, University of Vigo, Ourense, Spain. 2Faculty of Law, International University of La Rioja, Logroño, Spain.
Surfactants are compounds that reduce the surface tension of the medium and that can form aggregates such as vesicles, foams, gels, micelles, aerosols, etc. [1]. The Critical Micelle Concentration (CMC) is the range concentration above which the micelles are formed; this property is fundamental to study of behaviour of surfactants [2]. CMC can be studied by different techniques such as stopped flow, temperature-jump (T-jump), fluorescence probes, light scattering or refractometry, inter alia [1,3,4]. All these experimental techniques require economic resources, reagents and long-time [1], to avoid this; we developed a model based on Artificial Neural Networks (ANN) to obtain values of CMC of non-ionic surfactants. All data required to develop the model were taken from the literature [4,5]. The topological descriptors used as input variables to determinate CMC were originally calculated by Jalali-Heravi et al. [4].
The best ANN model consists in an input layer with seven neurons, only one intermediate layer with fourteen neurons and one neuron in the output layer [1]. The training cases used to implemented the ANN model has a RMSE of 0.076 (R2= 0.995) and the validation cases, used to verified the good prediction power of the model, has a 0.100 (R2= 0.996). These errors correspond to 1.62% for training phase and 2.47% of error for validation phase [1]. These results represent an improvement 66.02% compared with the MLR model proposed by Jalali-Heravi et al. [4] (Figure). These results indicate that ANN model has a good predictive capability for values of CMC.
Figure caption: Experimental log CMC (CMCexp) versus predicted (CMCpred) for training values ( ) and testing values ( ) by ANN model [1] (left) versus Jalali-Heravi et al. [4] (right).
Acknowledgements: G. Astray thanks Ministerio de Educación of Spain for a FPU grant P.P. 0000 421S 14006. M.A Iglesias-Otero and O. Moldes acknowledges Univ. de Vigo for their grant P.P. 00VI131H64103.
[1] Astray, G.; Iglesias-Otero, M.A.; Moldes, O.A.; Mejuto, J.C., Tenside Surfactants Deterg. 2013, 50, 118-124. [2] Domínguez, A.; Fernández, A.; González, N.; Iglesias, E.; Montenegro, L., J. Chem. Educ. 1997, 74, 1227-1231. [3] Patist, A.; Oh, S.G.; Leung, R.; Shah, D.O., Colloids Surf. A: Physicochem. Eng. Aspects 2001, 176, 3-16. [4] Jalali-Heravi, M.; Konouz, E., Quantitative Structure-Activity Relationships 2000,19,135-141. [5] Van Os, N.M.; Haak, J.R.; Rupert, L.A.M., Physico-Chemical Properties of Selected Anionic, Cationic and
Nonionic Surfactants. Elsevier: Amsterdam, 1993.
MODELING AND SIMULATIONS 212
P68 A numerical tool for analyzing equilibrium capillary rise
D. Blasco-Avellaneda1,*, A. Amirfazli2, M. A. Rodríguez-Valverde1, M. A. Cabrerizo-Vílchez1.
1Deptartment of Applied Physics, University of Granada, Campus of Fuentenueva, E-18071 Granada 2Department of Mechanical Engineering,York University, Toronto, ON, M3J 1P3
The continued miniaturization in the integrated circuits industry presents a problem of increasing importance: the pattern collapse [1, 2]. To understand the pattern collapse phenomenon better, a numerical model based on Surface Evolver was developed to predict the equilibrium shape and height of a meniscus confined between two plates in capillary regime (when surface tension dictates the meniscus shape) [3]. Such model also has applications in fiber and hair wetting. We obtained a simple and robust model validated with well-established laws (Jurin’s law, Laplace equation). We tackled a wide range of system features and configurations: plate-to-plate distance, plate width, contact angle plate, plates composed of different material, inclined plates, angle between plates, limiting plate height; with all results contrasted with the theory and validated by it. Consequently, our approach is able to be adapted to the specific characteristics of the various issues raised in the unsolved problem of pattern collapse.
(a)
(b)
(c)
Figure caption: (a) Water meniscus confined between two vertical plates separated by 1 l0 and with a width10 l0. (b) Dimensionless equilibrium height of meniscus in terms of dimensionless plate-to-plate distance for two contact angles (17º and 45º). (c) Dimensionless capillary pressure at the meniscus apex in terms of dimensionless equilibrium height for a contact angle equal to 17º and different plate-to-plate distances (d� l0).
Acknowledgements: This work was supported by the “Ministerio Español de Ciencia e Innovación” (project MAT2011-23339) and the “Junta de Andalucía” (projects P08-FQM-4325 and P09-FQM-4698)
[1] Collapse of patterns with various geometries during drying in photolithography: numerical study. Chini, S. F., Amirfazli, A., J. Micro/Nanolithogr., MEMS, and MOEMS 2012, 11, 033003.
[2] Understanding pattern collapse in photolithography process due to capillary forces. Chini, S. F., Amirfazli, A., Langmuir 2010, 16, 13707-13714.
[3] Capillary rise in a microchannel of arbitrary shape and wettability hysteresis loop. Wang, Z., Chang, C.C., Hong, S.J., Sheng, Y.J., Tsao, H.K., Langmuir 2012, 28, 16917�16926.
MODELING AND SIMULATIONS 213
P69 Self-Assembly of a long-chain ionic surfactant at low concentrations: a
simulation study Javier Burgos, Conxita Solans and Alessandro Patti*
Institute of Advanced Chemistry of Catalonia (IQAC-CSIC) and CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN)
Jordi Girona 18-26, 08034 Barcelona, Spain. *[email protected]
Above the critical micellar concentration (cmc), surfactants with the right solvophobic/solvophilic ratio self-assemble and form aggregates. At the cmc, the concentration of free surfactants in solution stops increasing, whereas that of aggregates starts to increase. Depending on several conditions, such as temperature, solvent, electrolytes, cosurfactants, and on the surfactant architecture as well, the cmc can vary rather significantly as well as the shape and size of micelles at equilibrium [1]. Due to their large applications in formulation chemistry and in nanotechnology as templates for the synthesis of advanced materials, the principles controlling self-assembly and micellization of surfactants are of fundamental relevance. In the last decades, computer simulations have played a key role in determining the phase and aggregation behavior of many different amphiphilic systems, via the implementation of both rigorous atomistic [2,3] and coarse-grained (CG) [4-6] models.
In this work, by performing lattice Monte Carlo (MC) simulations, we investigate the self-assembly of a cationic surfactant (ricinoleamidopropyltrimonium methasulfate) which finds large applications in formulation chemistry and, more specifically, in cosmetics. We apply an efficient CG model [6] where the surfactant molecules are represented as linear chains of connected beads in a three-dimensional lattice network. The headgroups, carrying the charge, are neutralized by a number of monovalent counterions. The charged groups interact via a Coulombic potential and a hard core repulsion, whereas neutral tail-tail interactions are only established between close neighbors, defined by the lattice coordination number. All the lattice sites are occupied by the surfactant or by the solvent. By tuning the mutual interaction between the solvophilic and solvophobic groups, and that between them and the solvent, we are able to observe aggregation and formation of micelles. We compute the cmc, the density distribution profiles in the micelles, their aggregation number, and the distribution of the counterions. Our results are compared with experimental results carried out in our laboratory.
Acknowledgements: Spanish Ministry of Science and Innovation, grants CTQ2011-29336-C03-01 and JCI-2010-06943. Generalitat de Catalunya, Grant 2009SGR-961
[1] J. N. Israelachvili, Intermolecular and Surface Forces, Academic Press, 2nd Ed., 1998. [2] M. Jorge, J. Mol. Struct.: THEOCHEM, 2010, 946, 88-93. [3] S. Pal, B. Bagchi and S. Balasubramanian, J. Phys. Chem., 2005, 109, 12879. [4] A. Patti, A. D. Mackie and F. R. Siperstein, Langmuir, 2007, 23, 6771-6780. [5] A. Patti, R. Ramsch and C. Solans, J. Phys. Chem. B, 2012, 116, 2687-2695. [6] D. W. Cheong and A. Z. Panagiotopoulos, Langmuir, 2006, 22, 4076-4083.
MODELING AND SIMULATIONS 214
P70 Balance Hidrofílico-Lipofílico HLBTR. Escala Termodinámica
J. Gracia-Fadrique1,*, J. L. López-Cervantes1, F. D. Sandoval-Ibarra1 and A. Amigo-Pombo2
1Facultad de Química, Departamento de Fisicoquímica, U.N.A.M., México, D.F., 04510, México. 2Departamento de Física Aplicada, Facultad de Física, Universidad de Santiago de Compostela, E-
15782, Santiago de Compostela, España. *[email protected]
El acoplamiento del potencial químico no ideal de la superficie, proveniente de la ecuación de Volmer, RT, y del potencial químico no ideal de la fase líquida, proporciona una relación lineal en presión superficial, en el intervalo menor o igual a la concentración micelar crítica [4].
**ln 1 ln ; o cmcz x x
x (1)
donde * corresponde a la presión reducida o relación entre la presión superficial y la presión superficial máxima, m, la pendiente z0 y el coeficiente de actividad a dilución infinita �. La ecuación (1) presenta como ventajas, además del comportamiento lineal, condiciones de frontera que contienen respectivamente la energía estándar de adsorción y la energía estándar de micelización; evaluada en saturación el coeficiente de actividad se identifica como el reciproco de la concentración micelar crítica. Ya que la periodicidad por contribución de grupos está presente en régimen diluido (Traube; RT ln3) y la energía estándar de adsorción contiene a la micelización, la ec. (1) explica entonces la reinterpretación del coeficiente de actividad a dilución infinita mediante contribuciones hidrofílicas HFIL e hidrofóbicas
HFOB [2-3]. ln ln lnHFOB HFIL
(2)
El coeficiente de actividad a dilución infinita, en una serie homóloga de tensoactivos, cuantifica termodinámicamente el efecto hidrofóbico en función de la temperatura, disolvente y terceros componentes en disolución; propiedades no presentes en las escalas convencionales del HLB. En términos de propiedades funcionales de un tensoactivo, es conveniente proponer una relación porcentual en una escala fundada en las contribuciones termodinámicas moleculares a la no idealidad y con una mayor sensibilidad a las variaciones hidrofílicas, de donde surge la expresión correspondiente del balance hidrofílico-lipofílico termodinámico (HLBTR)
ln100
lnHFIL T
HLBTRT
(3)
Figura: a) HLBTR para el nonilfenol etoxilado y el p-t-orctilfenol etoxilado en función del número de óxido de etileno. b) HLBTR para los n-alcoholes y n-alcoholes etoxilado en función del número de carbonos.
[1] Viades-Trejo, J.; Abascal-González, D. M.; Gracia-Fadrique, J., J. Surfact. Deterg. 2012, 15, 637-645 [2] Calvo, E.; Bravo, R.; Amigo, A.; Gracia-Fadrique, J., Fluid Phase Equilib., 2009, 282, 14-19 [3] Viades-Trejo, J.; Gracia-Fadrique, J., Fluid Phase Equilib. 2008, 264, 12-17 [4] Viades-Trejo, J.; Amigo, A.; Gracia-Fadrique, J., Fluid Phase Equilib. 2006, 250, 158-164
�
10 20 30 40
4
8
12
16
20
Nonilfenol etoxilado
HLB
TR
número de óxidos de etileno
p-t-Octilfenol etoxilado a
4 6 8 10 12 14
10
20
30
40
50
n-Alcohol etoxilado
HLB
TR
número de carbones
n-Alcohol b
MODELING AND SIMULATIONS 215
P71 Computational tools for forecasting the effect of small organic molecules upon
electric percolation of AOT-based microemulsions Ó. A. Moldes1,*, G. Astray1,2, A. Cid3 and J.C. Mejuto1
1Physical Chemistry Department, University of Vigo, 32004 Ourense, Spain. 2Faculty of Law, International University of La Rioja, Logroño, Spain
3Chemistry Department, REQUIMTE-CQFB, University Nova of Lisbon, 2829-516 Monte de Caparica, Portugal.
Microemulsions are ternary systems composed of droplets of a dispersed phase distributed in a continuous phase and separated of it by a surfactant film in a dynamic structure. A low conductivity is characteristic of AOT-based w/o microemulsions, but also the electrical percolation phenomenon [1]. This consist in a sharp increase observed in conductivity when either temperature or volume fraction of the dispersed phase reach a specific critical value. Electrical percolation depends strongly on the rigidity of the surfactant film. A softer film promotes shocks among microdroplets that ultimately allow charge transport, while a stiffer film reduces likelihood of effective shocks, decreasing and increasing percolation threshold temperature respectively. Presence of different molecules as additives, through their different solubility on microemulsion components, modifies rigidity of the surfactant film and consequently, percolation threshold.
Although there are some theories to explain percolative behavior, none of them consider effects of additives. Considering this, the point of this work has been to develop a simulation tool for percolative behavior of AOT-based microemulsions (w/o AOT/iC8/H2O microemulsions) under the influence of small organic molecules as additives. Simulations have been based on multilayer perceptrons, one of the most famed artificial neural network architectures [2].
Networks have been designed with three inputs (W value of microemulsions, additive concentration and log P). Network with better accuracy can predict percolation temperature of a microemulsion with a specific concentration of additive. That network is composed of three input neurons, two neurons in a hidden layer and one output neuron. R-values for training and validation have been 0.9251 and 0.9719 respectively. The most relevant variable for this model is log P.
Figure caption: Scheme of the obtained multilayer perceptron.
Acknowledgements: Dr. Astray thanks to Ministry of Education for his FPU contract (PP 421S 14 006 0000), Dr. Cid thanks to MCTES-FCT (Portugal) his post-doctoral grant (SRFH/BPD/78849/2011), while Moldes thanks University of Vigo for a grant.
[1] García-Río, L; Mejuto. J.C.; Pérez-Lorenzo, M.; Rodríguez-Álvarez, A.; Rodríguez-Dafonte, P., Langmuir 2005, 21, 6259-6264.
[2] Hornik, K.; Stinchcombe, M.; White, H., Neural Networks 1989, 2, 359-366
BIOTECHNOLOGICAL APPLICATIONS 216
P72 Does incubation time affect the formation of the protein corona?
Ana L. Barrán-Berdón1,2,*, Daniela Pozzi2, Giulio Caracciolo2, Anna Laura Capriotti3, Giuseppe Caruso3, Chiara Cavaliere3, Anna Riccioli4, Sara Palchetti4 and Aldo Laganà3
1Departamento de Química Física I, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040-Madrid, Spain
2Department of Molecular Medicine, “Sapienza” University of Rome, Viale Regina Elena, 291, 00161, Rome, Italy
3Department of Chemistry, “Sapienza” University of Rome, P.le A. Moro 5, 00185 Rome, Italy 4Dipartimento di Scienze Anatomiche, Istologiche, Medico-Legali e Dell'apparato Locomotore,
“Sapienza” University of Rome, P.le A. Moro 5, 00185 Rome, Italy *[email protected]
When administered in vivo nanoparticles (NP) interact with plasma proteins and are covered by a rich protein layer, the “protein corona”, whose composition changes in time due to continuous protein binding and unbinding events. The most relevant implication is that the identity of the bare NP is rapidly lost, and the biological behavior is controlled by its time-evolving protein corona [1-3]. In this study we investigate the time evolution of the protein corona associated with lipid nanoparticles whose lipid envelope is a binary mixture made of the cationic lipid 3 - N-(N´,N´-dimethylaminoethane)-carbamoyl (DC-Chol) and the zwitterionic lipid dioleoylphosphatidylethanolamine (DOPE) in the range between 1 min and 1 hour. Exposing DC-Chol–DOPE lipid vesicles to human plasma, a clear evolution of the associated protein corona over time was observed. Mass spectrometry of the digested protein corona revealed apolipoproteins as the most abundant component, which suggests an improved biocompatibility and indicates novel opportunities for targeted drug delivery. Given the abundance of apolipoproteins in the corona of DC-Chol–DOPE/HP complexes our thought was to target PC3 prostate carcinoma cell lines that constitutionally express high levels of the alipoprotein receptor. Combining laser scanning confocal microscopy experiments with flow cytometry we could demonstrate that DC-Chol–DOPE/HP complexes enter PC3 cells by a receptor-mediated endocytosis.
[1] Casals, E.; Pfaller, T.; Duschl, A.; Oostingh, G. J.; Puntes, V., ACS Nano 2010, 4, 3623-3632. [2] Lundqvist, M.; Stigler, J.; Cedervall, T.; Berggård, T.; Flanagan, M. B.; Lynch, I.; Elia, G.; Dawson,
K. A., ACS Nano 2011, 5, 7503-7509. [3] Mahon, E.; Salvati, A.; Baldelli Bombelli, F.; Lynch, I.; Dawson, K. A., J. Control. Release 2012,
161, 164-174
BIOTECHNOLOGICAL APPLICATIONS 217
P73 The effect of fluorinated cholesterol derivative on the stability and physical
properties of cationic DNA vectors A. Martín-Molina1,*, D. Paiva2, I. Cardoso3, M. Quesada-Pérez4, M. d. C. Pereira2 and
S. Rocha2
1Department of Applied Physics, University of Granada, Spain. 2LEPAE, Department of Chemical Engineering, University of Porto, Portugal.
3Molecular Neurobiology, IBMC – Instituto de Biologia Molecular e Celular and Escola Superior de Tecnologia da Saúde do Porto, Portugal.
4Department of Physics, University of Jaén, Spain. *[email protected]
Liposomes of the cationic lipid DOTAP (1,2-dioleyl-3-trimethylammonium-propane) and the fluorinated cholesterol derivative, heptafluorocholesterol (F7-CHOL), were tested at the molar ratios of 1:1 for DNA compaction and transfection. Their properties were correlated to the characteristics of the well-known system DOTAP and cholesterol (CHOL). The mass lipid/DNA (L/D) ratios at the isoelectric point were within the ranges 3 – 4 for DOTAP:CHOL and 4 – 5 for DOTAP:F7-CHOL, as determined by electrophoretic mobility measurements. These results and the ethidium bromide fluorescence intercalation assays confirmed that more DOTAP:F7-CHOL liposomes are needed to compact the same amount of DNA as DOTAP:CHOL. The phase diagrams of aggregation and re-entrant condensation phenomena obtained by phenomenological theory support this conclusion and established also that the liposome-DNA binding is stronger in the case of DOTAP:F7-CHOL/DNA system. The stability rates of both liposomes in the presence of DNA were similar as well as the transfection efficiencies, which support the application of heptafluorocholesterol as helper lipid in cationic liposomes for DNA delivery [1].
Acknowledgements: This work was financed by FCT and FEDER through COMPETE (projects PTDC/QUI-BIQ/102827/2008 and PTDC/QUI-BIQ/118076/2010), by MICINN of Spain (projects MAT2012-36270-C04-02 and -04), by Junta de Andalucía (project P09-FQM-4698) and CEIBioTic Granada (project 20F12/16). D. Paiva thanks FCT for a PhD fellowship (SFRH/BD/45384/2008).
[1] Paiva, D.; Martin-Molina, A.; Cardoso, I.; Quesada-Perez, M.; Pereira, M. d. C.; Rocha, S. Soft Matter 2013, 9, 401-409
BIOTECHNOLOGICAL APPLICATIONS 218
P74 BIONANOPARTICLES
Aintzane Pikabea, Garbiñe Aguirre, Ainara Imaz, Jose Ramos, and Jacqueline Forcada*
POLYMAT, Bionanoparticles Group Department of Applied Chemistry, UFI 11/56
Faculty of Chemistry, University of the Basque Country UPV/EHU Apdo. 1072, Donostia-San Sebastián, 20080, Spain
The challenges in the production of new nanoparticles for bio-applications are related to the necessity or bio-applications in which they could be used. But to the moment, an in deep study on the possibilities of biocompatible and also biodegradable nanoparticles directed to bio-applications (diagnosis, drug and gene delivery, among others) is in its infancy. On the one hand, environmental sensitive soft nanoparticles in the colloidal range offer unique advantages for biotechnological applications due to their tunable size from nanometers to micrometers, a large surface area for multivalent bioconjugation (a reaction forming a stable covalent link between at least two biomolecules), and an internal network useful for incorporation of biomolecules or drugs. However, the development of new synthesis strategies to incorporate functional groups (specific ligands) inside biocompatible nanoparticles will be one of the challenges to be overcome for using this type of nanomaterial for theranostic purposes. On the other hand, works devoted to the hybrid technology are of great interest and stimuli responsive hybrid colloids containing organic and inorganic components are a matter of study due to their attractive properties for pharmaceutical and biomedical applications. In this way, future work on biocompatible polymers-based hybrid nanoparticles will be directed to produce new families of hybrid nanoparticles for using in therapeutic treatments requiring the use of magnetic fields.
Concerning future perspectives, although a significant progress in the understanding of the general behavior of hard, hybrid, and soft nanoparticles for bio-applications has been achieved in the last decade, a lot of interesting work remains to be done on new specific bionanoparticles. Our research lines can be summarized as follows:
Synthesis and characterization of hard, hybrid, and soft nanoparticles for bio-applications.
Colloidal and polymeric characterizations of bionanoparticles. Modeling the heterogeneous polymerization processes to produce hard, hybrid, and
soft nanoparticles for bio-applications. In vitro preliminary bio-applications using hard, hybrid, and soft bionanoparticles.
Acknowledgements: This work has been supported by the Spanish Plan Nacional de Materiales (MAT2012-36270-C04-01). [1] Aguirre, G.; Ramos, J.; Forcada, J., Soft Matter 2013, 9, 261-270. [2] Ramos, J.; Imaz, A.; Forcada, J., Polymer Chemistry 2012, 3, 852-856. [3] Ramos, J.; Forcada, J., Langmuir 2011, 27,7222-7230. [4] Ramos, J.; Imaz, A.; Callejas-Fernández, J.; Barbosa-Barros, L.; Estelrich, J.; Quesada-Pérez, M.;
Forcada, J., Soft Matter 2011, 7, 5067-5082. [5] Costoyas, A.; Ramos, J.; Forcada, J., J. Polym. Sci. Part A: Polym. Chem. 2009, 47, 6201-6213. [6] Costoyas, A.; Ramos, J.; Forcada, J., J. Polym. Sci. Part A: Polym. Chem. 2009, 47, 935-948.
BIOTECHNOLOGICAL APPLICATIONS 219
P75 Synthesis and characterization of degradable and biocompatible poly( -amino
ester)-DNA complexes Azahara Rata-Aguilar1, Juan L. Ortega-Vinuesa1,*, Ana B. Jódar-Reyes1, Antonio Martín-
Rodríguez1, Nathaly Segovia-Ramos2, Víctor Ramos-Pérez2 and Salvador Borrós2 1Biocolloid and Fluid Physics Group, Department of Applied Physics, University of Granada, 18071
Granada, Spain. 2Group of Material Engineering GEMAT-IQS, University of Ramon Llull, 08017 Barcelona, Spain.
One of the approaches to deal with the development of non-viral gene carriers based on DNA condensation by cationic polymers consists on analysing the forces involved in the formation of the corresponding polyplexes. The long-range electrostatic attraction between the negative phosphate groups of the DNA chain and many polycations is usually complemented with short-range van der Waals attractions, and, in some cases, with hydrophobic forces among non-polar moieties. To gain an insight into this aspect, in the present work we study the effect of incorporating a small aliphatic chain to biodegradable linear poly( -amino esters) on compaction of a plasmid DNA. The physicochemical characterization of the formed polyplexes has been carried out by means of dynamic light scattering (DLS), laser Doppler electrophoresis, Nanoparticle Tracking Analysis (NTA) and agarose gel electrophoresis. Our results suggest that the inclusion of a small hydrophobic fragment into the polycation backbone may improve the overall properties of synthetic DNA carriers, in such a way that the formed polyplexes became more positively charged at high polymer loads, the degradation by hydrolysis was slowed down, they became more resistant to aggregate at high polymer concentration loads, and a better protection of DNA strands was achieved. Although nowadays many studies are mainly interested in the final transfection performance, studying other basic aspects, as the role played by different forces during compaction, the interaction potentials controlling the colloidal stability of the polyplexes or the degradation/desorption kinetics in simple and simulated biological media, may help to improve the development of future carriers.
Acknowledgements: The authors wish to express their appreciation for the financial support granted by the following research projects: MAT2010-20370 - European FEDER support included - (MICINN, Spain), P07-FQM3099 and P10-CTS-6270 (Junta de Andalucía, Spain), CEIBiotic 20F12/16. Azahara Rata-Aguilar thanks the Government of Spain (MECD) for her FPU fellowship. GEMAT group would like to thank Generalitat de Catalunya for its support through the Consolidated Grant 2009 SGR 1461.
[1] Wagner, E., Pharmaceutical Reseach 2004, 21, 8-14. [2] Monserrat, M.; Garreta, E.; González, F.; Gutiérrez, J.; Eguizábal, C.; Ramos, V.; Borrós, S.; Izpisua
Belmonte, J.C., J. Biol. Chem. 2011, 286, 12417-12428. [3] Estévez-Torres, A.; Baigl, D., Soft Matter 2011, 7, 6746-6756.
BIOTECHNOLOGICAL APPLICATIONS 220
P76 Silicon colloids based applications to biosensing and sun resistant materials
I. Rodriguez1,2,*, R. Fenollosa1,2, and F. Meseguer 1,2
1Unidad Asociada ICMM/CSIC-UPV, Universidad Politécnica de Valencia, 42022. 2Instituto de Ciencia de Materiales de Madrid (CSIC), Cantoblanco, 28049 Madrid (Spain).
We have recently developed a new type of silicon structure that we name as Silicon Colloids [1]. They are able to scatter light very efficiently in a large-span frequency range, covering form the visible to the far infrared regions. Silicon colloids have unique properties because: A) They behave as optical microcavities with a high refractive index. B) Their small size (from several hundred nanometers to few micrometers) and smooth round surface open the possibility of developing powders and pigments, able to block the infrared and thermal radiation coming from either the sun or from any other hot body. C) As they are made of a semiconductor material they can be further processed for developing electronic devices.
Here we report on the processing of silicon colloids as well as their applications to: 1. Nanomaterials for sensing [2,3] 2. IR protective coatings [4] 3. Sun resistant plastics and polymers [5]
[1] R. Fenollosa, F. Meseguer, and M. Tymczenko, Patent WO 2008155438 [2] F. Ramiro-Manzano, et al. Adv. Mater. 2011, 23, 3022 [3] I. Rodriguez et al., Submitted. [4] I. Rodriguez, R. Fenollosa, A. Perez-Roldan and F. Meseguer, Patent WO 2011092368 and
Cosmetics&Toilettries, Sept. 2010. [5] I. Rodriguez, R. Fenollosa, A. Perez-Roldan and F. Meseguer, Patent WO 2012101306
BIOTECHNOLOGICAL APPLICATIONS 221
P77 Surface modification of lipid nanoparticles using poloxamer 407 surfactant.
Effects on cellular uptake P. Sánchez-Moreno1, J. L. Ortega-Vinuesa1, J. A. Marchal-Corrales2, Anna Salvati3, K. A.
Dawson3, J. M. Peula-García4
1Biocolloids and Fluids Physics Group, Dpt. of Applied Physics, University of Granada, Spain. 2Human Anatomy and Embryology Department, University of Granada, 18071 Granada, Spain
3Centre for BioNano Interactions,University College Dublin, Belfield, Dublin, Ireland. 4Dpt. of Applied Physics II, University of Málaga, Spain.
A lot of studies indicate the importance of the nanoparticle-surface shell structure in cell uptake pathways and denote the role of particle design in nanomedicine. In this work, we have synthesized and physico-chemically characterized four different lipid-nanoparticles systems in which the core was constituted by olive oil and the shell by phospholipids (lecithin), poloxamer 407 (Pluronic® F127), and their combinations. The principal aim was to investigate the effect of the nanostructure surface on the lipid-nanoparticle uptake process in a human lung adenocarcinoma epithelial cell line (A549). The presence of hydrophilic polymers (poloxamers) in the surface enhances the intrinsic colloidal stability of the system and it also influences their interaction with plasma proteins, which is a process that may have an important impact on the in vivo long-term stability of the nanosystem [1] and on the nanoparticle-cell interactions [2]. The uptake process was analyzed in vitro with flow cytometry and cytotoxicity experiments using loaded nanoparticles with a fluorescent dye and a hydrophobic cytotoxic drug respectively, being confirmed by confocal microscopy. The experimental results showed an increase of the uptake amount increasing the phospholipid concentration in the nanoparticle shell. The main reason for this result could be attributed to the structural similarities between the phospholipidic coating of the nanoparticles and the cell membrane.
Figure caption: Relative fluorescent intensity of the A549 cell line when incubated with Nile-Red-loaded
nanocapsules for different times.
Acknowledgements: P. Sánchez-Moreno thanks to the European Science Foundation for their scolarship inside the project: “Mapping the detailed composition of surface adsorbed protein layers on biomaterials and nanoparticles”. The authors thank the financial support given by the projects MAT2010-20370 (European FEDER support included, MICINN, Spain), and P07-FQM2496, P10-CTS-6270 and P07-FQM3099 (Junta de Andalucía, Spain).
[1] Sánchez-Moreno P., Ortega-Vinuesa J.L., Martín-Rodríguez A., Boulaiz H., Marchal-Corrales J.A. and Peula-García, J.M., Int. J. Mol. Sci. 2012, 13, 2405-2424.
[2] Lynch I., Salvati A., Dawson K.A., Nature Nanotech. 2009, 4, 546-547.
BIOTECHNOLOGICAL APPLICATIONS 222
P78 Rationale design of nanoemulsions for the delivery of hydrophobic bioactive
compounds: from surfactants and interfaces to in vivo results Miguel Wulff-Pérez1, Antonio Martín-Rodríguez1, Juan de Vicente1, Antonia Serrano2,
Francisco Javier Pavón2, María J. Gálvez-Ruíz1,*
1Biocolloid and Fluid Physics Group, Applied Physics Department, University of Granada, Fuentenueva s/n, 18071,Granada, Spain
2Fundación IMABIS, Hospital Carlos Haya de Málaga, Laboratorio de Medicina Regenerativa, Avenida Carlos Haya 82, 29010, Málaga, Spain
Oil-in-water nanoemulsions (i.e. nano-sized droplets of oil dispersed in water) present several advantages to be used as delivery systems for hydrophobic drugs: great stability against creaming/sedimentation, large surface area, possibility of intravenous administration, high biocompatibility, etc [1]. However, our knowledge of the relationship between composition and final in vivo properties needs to be improved in order to design rationally these nanoemulsions as carriers. In this work, nanoemulsions have been prepared using natural oils and FDA-approved polymeric surfactants. The influence of the surfactant properties on the interfacial behavior as well as on the macroscopic properties of the nanoemulsions has been analyzed. In vitro tests have been also carried out to select the best in vitro performance, by studying the impact of the surfactant structure on the biodegradation of these nanoemulsions (lipolysis). Finally, the optimized nanoemulsions have been used to administer oleoylethanolamide, a natural hydrophobic compound with anti-obesity properties. Nanoemulsions containing oleoylethanolamide have been administered then to Wistar rats, both orally and parenterally, and the effects of this formulation on the food intake have been monitored. The in vivo results showed a good performance of the nanoemulsions as carriers of hydrophobic compounds, confirming the properties predicted on a basis of a fundamental science approach.
Acknowledgements: Authors thank the financial support given by the projects: P07-FQM03099 (Junta de Andalucía), CEI-BioTic 20F12/16 y Micro proyecto CEI BioTic Granada, convocatoria 2013 (Campus de Excelencia Internacional BioTic Granada) y MAT2010-20370 (Ministerio de Educación y Ciencia, España).
[1] Tadros, T.F.; Izquierdo, P.; Esquena, J.; Solans, C., Adv. Colloid Interface Sci. 2004, 108, 303–318.
AUTHOR INDEX
AUTHOR INDEX 225
A Acosta, E. P60 Adboudzadeh, A. P28 Aguilella-Arzo, M. O6.5 Aguirre, G. P74 Ahijado-Guzmán, R. O7.1 Aicart, E. PSS21 Aicart-Ramos, C. PSS21 Alatorre-Meda, M. O1.13, P19, P64 Alejo, T. O5.7, P61 Almeida, C. R. M. P24 Alsina, M. A. PSS18, P62 Altantzi, T. CT2 Álvarez, L. J. P34 Alvarez-Puebla, R. O1.4, P11 Alves, C. P40 Alves, L. PSS09, P23, P25,
P27 Amaral, V. S. P18 Amigo, A. P60, P70 Amirfazli, A. P68 Angelova, A. O6.5 Anta, J. A. I6, O6.3, O6.6 Antunes, F. E. PSS09, P23, P25,
P27 Araújo, J. P. P12 Araújo, M. J. P37 Arellano-Varela, J. E. P59 Arias-Estevez, M. P49 Arzac, A. P41 Astray, G. P67, P71 Asua, J. M. P09 B Baghdadli, N. P33 Bagherifam, S. O1.11 Bailey, A. E. O2.2 Bals, S. CT2, P14 Bar, I. P. O5.1 Barandiaran, M. J. P28 Barata, J. F. B. P01 Barbosa, S. O1.13, P19, P29 Barrán-Berdón, A. L. PSS21, P72 Bastos-González, D. I5, O5.6, P46,
P63 Benavente, J. O5.3, P20 Blanc, C. PL1 Blanco, M. C. O4.2 Blasco-Avellaneda, D. P56, P68 Blazevska-Gilev, J. P41
Blomberg, E. O2.3 Bonales, L. J. O5.4 Bordi, F. PSS14 Borrós, S. P75 Böttcher, A. PSS09 Braeckmans, K. O3.1 Brezesinski, G. P65 Buceta, D. O4.2 Burboa, G. PSS19, P64 Burgos, J. P69 Busquets, M. A. PSS01, P03, P62 Burrows, H. D. O1.12, O2.4,
PSS08, P26 C Cabrerizo-Vílchez, M. A. O5.2, O5.5,
PSS02, PSS16, P56, P59, P66, P68
Cajal, Y. P58 Calderó, G. O3.3, PSS07 Callejas-Fernández, J. O6.3, P42, P46 Calvo, E. P60 Camacho, L. P65 Cambón, A. O1.13, P19, P29 Cano-Sarabia, M. O6.5 Capriotti, A. L. P72 Caracciolo, G. P72 Cardoso, A. M. S. O7.4, P40 Cardoso, I. P73 Carnero-Ruiz, C. P30, P36 Carregal-Romero, S. O1.1, O1.7, P19 Caruso, G. P72 Carvalho, H. PSS23 Carvalho, R. S. P43 Casals, E. O1.13 Cascante, M. P51 Castelletto, V. P29 Castelló, J. P03 Castro, R. A. E. O1.12 Castro-Hartmann, P. PSS21 Cavaleiro, J. A. S. P01 Cavaliere, C. P72 Cazeneuve, C. P33 Cerdà, J. J. CT3 Chapel, J.-P. O5.6 Charas, A. I7 Chen, S. PSS02 Chmelka, B. F. CT2 Chuliá, R. O5.4 Cid, A. P50, P71
AUTHOR INDEX 226
Claesson, P. O2.3 Clara-Rahola, J. P48 Colomer, A. P44 Contreras-Cáceres, R. P48 Coronado-Puchau, M. O1.14 Costa, C. P25, P27, P45 Costa, T. O2.4, PSS08 Creaney, B. O1.5 Cruz-González, S. O1.10 Cuetos, A. O6.1, O6.6 D Damas, L. P02 Daniel-da-Silva, A. L. O1.5, P01, P12,
P18, P43 Dashtimoghadam, E. O1.6 David, C. O1.10 Daviña, R. P54 Dawson, K. A. P77 de Azebedo, D. PSS08 de Vicente, J. O4.1, PSS20,
P21, P78 de Zea Bermudez, V. O1.12 Delgado, A. V. P52 Dias, R. S. I3, PSS10 Domènech, O. P62 Donaldson Jr, S. H. CT2 do Vale, M. L. C. O3.5, O7.4,
PSS15, P40, P45 Drummond, C. I5, O5.6, P63 Duarte, C. M. G. PSS09 E Edgar, J. O7.1 Elaissari, A. CT1, P06 Escribano, B. CT7 Escribano, E. PSS01 Espinosa, G. O2.2 Espuny, M. J. P44 Esquena, J. O2.3, PSS07 Estelrich, J. PSS01, P03, P04 F Fajgar, R. P41 Fanun, M. PSS11 Faraudo, J. I5, O6.5 Fateixa, S. O1.3 Féliz, D. O3.5 Fenollosa, R. O1.2, P76 Fernandes, A. M. P28
Fernandes, R. O5.1 Fernández-Barbero O3.6, P39, P48 Fernandez-Nieves, A. PL1, P55 Fernández-Piñas, F. P13 Fernandez-Rodriguez, M. A. PSS02, P66 Fernandez-Rubio, J. E. O5.4, O5.8 Ferrer-Tasies, L. O6.5 Fessi, H. CT1 Fey, A. O1.4, P11 Figueira-González, M. O2.6 Fijten, M. I8 Firmino, T. O6.4 Fischer, V. O1.14 Fonseca, S. M. O2.4, P26 Forcada, J. P42, P74 Francisco, V. O2.6, P45, Frisken, E. J. O2.2 Furó, I. O5.1 G Galceran, J. O1.10 Galera-Cortés, E. P04 Gallardo, M. A. PSS01, P03 Gálvez-Ruíz, M. J. P78 Garcés, J. L. P51 García, J. O5.3 García de Abajo, F. J. O1.4 García-Calvo, E. P13 García-Jara, L. PSS22 García-Río, L. O2.6, P45 Giner-Casares, J. J. P57, P65 Girona, V. PSS18, P62 Gomes, A. C. O3.1, O7.2,
PSS23 Gonçalves, O. PSS23 González, N. O1.13, P29 González, V. D. G. P46 González-Pérez, A. P29 Gonzalo, S. P13 Goris, B. CT2 Goy, S. O1.13 Graça, M. P01 Gracia, R. P28 Gracia-Fabrique, J. P60, P70 Grau-Campistany, A. P58 Griffiths, G. W. O1.11 Grzelczak, M. CT2, O1.8,
O1.14, P08, P14, P16
Gudiña, E. J. I1
AUTHOR INDEX 227
Guerrero-Barba, F. P59 Guerrero-Martínez, A. CT6 H Haake, H.-M. PSS09 Haba, E. P47 Hamley, I. P29 Hasirci, N. O1.11 Hasirci, V. O1.11 Hellweg, T CT5 Henkel, A. O7.1 Hernández, A. PSS24 Hernando, B. O5.3 Herrera-Márquez, O. P05 Heuts, H. I8 Hidalgo-Álvarez, R. O4.1, PSS02,
PSS20, P04, P21 Hierrezuelo, J. P20 Hierrezuelo, J. M. P30, P36 Holgado-Terriza, J. A. O5.2 Holm, C. CT3 Homs, M. O3.3 Hühn, D. O1.7 I Iglesias-Otero, M. A. P50, P67 Imaz, A. P42, P74 Infante, M. R. O3.2, PSS13, P44 Israelachvili, J. N. CT2 J Jimenez, G. PSS22 Jimenez de Aberasturi, D. O1.7 Jimenez-Millán, E. P65 Jódar-Reyes, A. B. P75 Jorge, A. F. PSS10 Juárez, J. PSS19, P64 Juárez-Ramírez, I. PSS06 Junquera, E. PSS21 Jurado, A. S. O7.4, P40 Jurado, E. P05 K Kaewsaneha, C. P06 Khorshid, N. P31 Klotz, B. PSS09 Knaapila, M. PSS08, P26 Knudsen, K. P31 Kraft, M. PSS08
L La Porta, A. P08 Ladj, R. CT1 Laganà, A. P72 Landfester, K. O1.14 Langer, J. P07 Le-Dantec, R. CT1 Leganés, F. P13 Leiza, J. R. P09 Lesieur, S. O6.5 Leyva-Porras, C. C. PSS06 Lima, M. C. P. O7.4, P40 Lindman, B. O3.2, PSS09,
P25, P27 Liu, C. O2.3 Liz-Marzán, L. M. CT2, CT6, O1.4,
O1.8, O1.14, PSS02, PSS04, PSS05, PSS17, P07, P08, P14, P15, P16, P17, P57
Llamas, S. P33 Lopes, C. B. P12, P18 Lopes, D. PSS03 Lopez-Cabarcos, E. P32 López-Cervantes, J. L. P60, P70 López-León, T. PL1 López-Quintela, M. A. O4.2 López-Romero, J. M. P20 Luckam, P. P38 Luengo, G. P33 Lund, R. O2.1 Luque-Caballero, G. O7.3 M Madurga, S. P51 Maestre, A. O2.7, P35 Maestro, A. O5.4 Mælandsmo, G. M. O1.11 Maldonado-Valderrama, J. O5.2, O7.3 Maldonado-Valdivia, A. O3.6, P39, P48 Mancebo, N. O5.4 Manresa, M. A. PSS13, P44, P47 Manso, J. A. PSS12, P49, P50 Marchal-Corrales, J. A. PSS22, P77 Maroto-Centeno O6.2 Marques, A. T. O2.4
AUTHOR INDEX 228
Marques, E. F. O2.6, O3.5, O5.1, O7.4, PSS15, P37, P40, P45
Martens, T. O3.1 Martín, V. I. O2.7, P34, P35 Martín-García, B. O1.9 Martín-Molina, A. O6.2, O7.3,
PSS21, P73 Martín-Rodríguez, A. PSS22, P75, P78 Martín-Romero, M. T. P65 Martínez-Pedrero, F. O5.4, O5.8 Mas, F. O1.10, P51 Mecerreyes, D. P28 Medronho, B. P25, P27 Mehravar, E. P09 Mejuto, J. C. PSS12, P49, P50,
P67, P71 Mendoza, A. J. O5.4 Merchán, M. D. O5.7, P61 Meseguer, F. O1.2, P76 Mezei, A. O2.5 Mezerji, H. H. P14 Miguel, M. G. O3.2, P27 Miraballes-Martínez, I. PSS24 Miras, J. O2.3 Mirzadeh, H. O1.6 Mitjans, M. PSS13 Moldes, O. A. PSS12, P67, P71 Molina, R. PSS07 Molina-Bolívar, J. A. P36 Moncho-Jordá, A. O6.3, P42 Monteiro, O. C. P10 Montenegro-Martos, J. M. O1.7 Moraila-Martínez, C. L. O5.5, PSS16 Morais, C. M. O7.4 Morales, J. PSS12, P49, P50 Morales, M. P. P21 Morales-Sánchez, A. P22 Morán, M. C. O2.5, PSS10 Moreno, M. P28 Moreno-Calvo, E. O6.5 Morros, J. O3.2 Mosquera, V. O1.13, PSS19,
P19, P29, P64 Mounier, Y. CT1 Moyá, M. L. O2.7, P34, P35 Muñoz, J. P53 Muñoz, M. P62 Muñoz-Bonilla, A. I8 Muñoz-Espí, R. O1.14
Muñoz-Juncosa, M. PSS18 Muñoz-Úbeda, M. PSS21 N Naous, M. P36 Nascimento, B. F. O. P24 Neiser, A. O7.1 Neves, M. C. PSS03, P10 Neves, P. M. S. P01 Nielsch, K. O5.3 Nieto-Ortega, B. P30 Nobili, M. PL1 Noguera-Marín, D. PSS16 Novikov, S. M. PSS17 Nunes, M. R. P10 Nunes, S. C. C. O6.4 Nyström, B. O1.6, O1.11, P31 O Oliveira, A. C. N. O3.1, O7.2 Oliveira, I. S. PSS15, P37 Oliveira, M. E. C. D. R. O3.1, O7.2,
PSS23 Ortega, F. O3.4, O5.4, O5.8,
P33 Ortega-Vinuesa, J. L. P75, P77 Ortiz, A. PSS18, P62 Ott, A. O1.1 P Pagonabarraga, I. CT4 Pais, A. A. C. C. O6.4, PSS10,
P02, P23 Paiva, D. P73 Palchetti, S. P72 Parajó, M. O2.6 Parak, W. J. O1.1, O1.7, P19 Pastor, I. P51 Pastoriza-Santos, I. PSS05 Patti, A. O6.1, P69 Pavlov, V. O1.14 Pavón, F. J. P78 Pazos-Perez, N. O1.4, P11 Pemartin, K. PSS06, P22 Perea, R. P38, P52 Pereira, E. P12, P18 Pereira, M. d. C. P73 Pereira, R. F. P. O1.12, P24 Pérez, L. PSS13 Pérez, L. PSS21, P44, P47
AUTHOR INDEX 229
Pérez-Fuentes, L. I5, P63 Pérez-García, S. A. PSS06 Pérez-Juste, J. CT2, PSS05, P14 Pérez-Mosqueda, L. M. P53 Perlich, J. P26 Persson, K. O2.3 Peula-García, J. M. PSS22, P77 Pikabea, A. P74 Pinazo, A. PSS13, P44, P47 Pinedo, R. O1.7 Pinheiro, P. C. P12 Piñeiro, M. P02, P24 Plaza, A. P05 Polavarapu, L. PSS04 Polpanich, D. P06 Pons, R. O2.5, O3.2,
PSS17, P44, P47 Pozzi, D. P72 Pradhan, S. P26 Pragana, J. O2.4 Prasad, J. O7.1 Prat, J. PSS18, P62 Prida, V. M. O5.3 Prieto, G. PSS14, P54 Puertas, A. M. I4, O6.6 Pujol, M. PSS18, P58, P62 Puntes, V. F. O1.13 Puy, J. O1.10 Q Queralt, J. PSS01 Quesada-Pérez, M. O6.2, P42, P73 Quindant, R. I10 R Rabanal, F. P58 Raemdonck, K. O3.1 Ramadan, Y. P32 Ramírez, P. P53 Ramos, J. P42, P74 Ramos-Pérez, V. P75 Ramos-Tejada, M. M. P38, P52 Rata-Aguilar, A. P75 Regev, O. O5.1 Rey-Castro, C. O1.10 Ricart, S. O6.5 Riccioli, A. P72 Richter, R. P. I1 Rivas, J. O4.2 Robles, E. P64
Rocha, J. P18 Rocha, S. P73 Rodea-Palomares, I. P13 Rodrigues, L. R. I2 Rodríguez, A. O2.7, P35 Rodríguez, I. P76 Rodríguez-Abreu, C. P55 Rodríguez-Dafonte, P. O2.6 Rodríguez-Fernández, D. PSS05 Rodríguez-González, B. P21 Rodríguez-Valverde, M. A. O5.5, PSS02,
PSS16, P56, P59, P66, P68
Rojo, T. O1.7 Romero, V. O5.3 Rosal, R. P13 Rosman, C. O7.1 Ruano, M. O3.4 Rubia-Payá, C. P65 Rubio, R. G. O3.4, O5.4, O5.8,
P33 Rubio-Retama, J. P32 Rudzka, K. P52 Ruiz, E. D. PSS19 Ruiz de Larramendi, I. O1.7 Ruiz-López, J. A. PSS20 S Saa, L. O1.14 Sabín, J. O2.2, PSS14 Salgueiro, A. M. O1.5 Salvador, J. O1.10 Salvati, A. P77 Sanchez, C. PL2 Sánchez, P. A. CT3 Sánchez-Domínguez, M. PSS06, P22 Sánchez-Iglesias, A. CT2, PSS02, P07,
P08, P14 Sánchez-Moreno, P. P77 Sánchez-Treviño, A. Y. P56, P66 Sande, S. A. P31 Sandoval-Ibarra, F. D. P70 Sangrà, M. PSS01 Sanz-Ortiz, M. N. P15 Sarmiento, F. PSS14, P54 Scarabelli, L. O1.8 Scherf, U. O2.4, PSS08, P26 Segovia-Gutiérrez, J. P. O4.1 Segovia-Ramos, N. P75 Serrano, A. P78
AUTHOR INDEX 230
Serrano-Montes, A. B. P16 Shi, L. O1.2 Shiohara, A. P07, P17 Shtein, M. O5.1 Sierra-Martín, B. O3.6, P39, P48 Silva, J. P. N. O7.2, PSS23 Silva, M. M. PSS03 Silva, N. J. O. P18 Silva, S. G. O3.5, O7.4,
PSS15, P40 Silvestre, A. J. P10 Sintes, T. CT3 Siretanu, I. O5.6 Solans, C. O3.3, PSS06,
P22, P55, P69 Solier, J. D. P04 Song, Y. PSS02 Sönnichsen, C. O7.1 Sóñora, C. PSS24 Sousa, C. T. P12 Sousa, J. J. P02, P23 Spasevska, D. P41 Stewart, B. O2.4, P26 T Taboada, P. I9, O1.13, PSS19,
P19, P29, P64 Tangboriboonrat, P. P06 Taromi, F. A. O1.6 Tavano, L. PSS13 Tavares, D. S. P12, P18, P43 Tebbe, M. P11 Teixeira, J. A. I2 Thormann, E. O2.3 Tirado-Miranda, M. P46 Toimil, P. P54 Tomovska, R. P41 Topete, A. O1.13, P19, P29 Torcello-Gómez, A. O5.2 Torkkeli, M. P26 Trindade, T. PL3, O1.3, O1.5,
PSS03, P01, P12, P18, P43
Tyrode, E. O2.3 V Valdes, M. A. PSS19, P64 Valente, A. J. M. O1.12, PSS08,
P24 Van Herk, A. I8
Van Tendeloo, G. CT2 Varol, H. S. O1.14 Vazquez, M. I. P20 Vázquez-Vázquez, C. PSS14 Veciana, J. O6.5 Vega, V. O5.3 Vela-Gonzalez, A. V. PSS06 Velázquez, M. M. O1.9, O5.7, P61 Ventosa, N. O6.5 Vereda, F. P21 Vicaria, J. M. P05 Vidal-Lopez, G. P22 Vilanova, N. P55 Vilar, E P19 Vilar-Vidal, N. O4.2 Vilaseca, E. P51 Vílchez, S. O2.3 Vílchez-Maldonado, S. PSS07 Villar-Alvarez, E. O1.13, P29 Vinardell, M. P. PSS10, PSS13 Vitorino, C. P02, P23 W Wagner, C. S. O1.4 Wedel, B. CT5 Wittemann, A. O1.4 Wulff-Pérez, M. P78 Z Zeiser, M. CT5 Zierold, R. O5.3
5th Iberian Meeting on Colloids and Interfaces, RICI5
Book of Abstracts
EDITORS Jacqueline Forcada
Josetxo Ramos
5th
Iber
ian
Mee
ting
on C
ollo
ids a
nd In
terf
aces
, RIC
I5B
ook
of A
bstra
cts
Edito
rs: J
acqu
elin
e Fo
rcad
a Jo
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o R
amos
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ISBN 978-84-9860-832-8
