Dr.S.GirijaLecturer

School of Biotechnology and Genetic EngineeringBharathiar University, Coimbatore – 46,

Tamil Nadu.

Biological Synthesis of nanoparticles

• Top Down (Breaking down)

Ball milling, Laser ablation

• Bottom up (Making large)

Chemical synthesis and Self assembly

• Biological Synthesis

Plants, Bacteria, Fungus and Yeast

• Top Down (Breaking down)

Ball milling, Laser ablation

• Bottom up (Making large)

Chemical synthesis and Self assembly

• Biological Synthesis

Plants, Bacteria, Fungus and Yeast

CHEMICAL SYNTHESIS

• In these mainly Cd, Zn, Se, Pd, Ti, Au , Ag are the some used most frequently.

a. ZnCl2 + Na2S = ZnS+ NaCl

b.Cd.2H2O (CH3 COO)2+ TG+ Na2S = CdS (Cadmium acetate) (Thioglycerol)

c. ZnEt2+ TOPse = ZnSe (Diethyl Zinc)TOPO- trioctyl phospine oxide (as a stabilizing agent)

TOPO/HDA

TOPO/HDA

CdSe

CdSe- ZnS

SURFACE COATING

• The surface coating plays important role in the nanopartile.

• The surface coating is usually done with organic compounds, polymers , biological compounds etc

Organic materials

Polymers Hydrophilic Hydrophobic

Importance of Surface coating1.Stability2.Water solubility3.Prevention of agglomeration 4.Enabling attachment of biological components5.Preventing the toxicity of the core shell

1.Simple technique

2.Inexpensive, less instrumentation compared to many physical

methods

3.Low temperature (< 350º C) synthesis

4.Doping of foreign atoms (ions) possible during synthesis

5.Large quantities of the materials can be obtained

6.Varieties of size are possible

7.Materials are obtained in the form of liquid but can de

converted into dry powder

8.Self assembly or patterning is possible

Advantages of Chemical synthesis

Nanoparticle synthesized using biological methods

• Silver• Gold• Indium• Cadmium

• Plants exploited• Neem• Aloe vera• Alfalfa• Cinnamomum• Avena • Eucalyptus• Pelargonium• Embelica

BIOLOGIAL SYNTHESIS OF NANOPARTICLS

• Using Plants• Using Microorganisms• Using Biological molecules such as

aminocids, DNA, protein templates.

• Using Viruses (TMV), Cowpea Chlorotic Mottle Viruses (CCMV), Brome Mosaic Viruses (BMV)

• Advantage: Reduced toxicity

Important reports

• Formation and Growth of Au Nanoparticles inside Live Alfalfa Plants J. L. Gardea-Torresdey, J. G. Parsons, E. Gomez,J. Peralta-Videa, 2002. Nano Letters.

• Rapid synthesis of Au, Ag, and bimetallic Au core–Ag shell nanoparticles using Neem (Azadirachta indica) leaf broth by Shiv Shankar,a Akhilesh Rai,Absar Ahmad,and Murali Sastry, 2004.

• Aspergillus fumigatus; (Right) Kinetics of silver nanoparticles synthesis in the aqueous medium containing cell filtrate of A. fumigatus

Plants used ..for synthesis

Alfalfa -

Aloe Vera

+ AgNO3Ag NPs

+

HAuCl4 AuNPs

Silver nano formation

• AgNO3 + H2O + Plant Extract Ag+

Ag(0)

AgNP

Synthesis of silver nanomaterials using plant extracts

1mM of AgNO3 Leaf extract

Mixed thoroughly

Kept in shaker at 200 rpm

Aged for 24 hours for complete reduction

The final mixture is centrifuged and washed twice with sterile water and suspended in minimal quantity of water

Reduction monitored using UV- VIS – Abs spectroscopy at 430nm

Room temperature

Characterization of nanomaterials

Gold nanoparticles (Aloe vera)

Synthesis of Gold

Nanotriangles and

Silver Nanoparticles

Using Aloe vera Plant

Extract by S. Prathap

Amino acids, DNA…..

Cystein capped ZnS nano for the nucleic acid determination

In Microorganism

• Extracellular synthesis of Silver nanoparticles by a silver tolerant yeast strain MKY3 has been reported.

• Fusarium oxysporus fungus was used to synthesize Silver nanoparticles.

• Biosynthesis of Silver nanoparticles by Pencillium fungi was used.

• Pseudomonas structzeri was to synthesize Silver nanoparticles.

• Magnetotactic bacteria, diatoms are also used

Protocol in Fungus

• 10g of Fusarium oxysporum biomass has to be taken in a conical flask containing de ionized water

• AgNo3 solution of (10-3M) has to be added, the reaction has to be carried out in dark

• Periodically aliquots of the reaction can be removed

Shapes and Size depends on experimental conditions

• Morality of precursor compounds

• Temperature of the synthesis

• Type of reducing agent used

• Type of capping and doping agent used

• Number of Washing

SHIFTING OF BAND IN INFRA RED REGION

AT 430NM

ZETA POTENTIAL OF COLLOIDAL SILVER NANOPARTICLE

Stable nanomaterials have the potential + or – 30 mV

DYNAMIC LIGHT SCATTERING OF COLLOIDAL SILVER NANOMATERIALS

HR-SEM ANALYSIS OF THE SILVER NANOMATERIALS

TEM IMAGRE OF SILVER NANOMATERIALS

Used to stain the Nucleus

• Imaging the living organisms like Animal, plant and microorganism at their cellular and molecular level using nanoparticles will bring an revolution in the field of research and development in biological sciences.

• Engineering of nanoparticles for the safer application

In Our Laboratory…

• Synthesis of Silver and Copper nanoparticles using biomolecules.

• Synthesis of Gold nanopartilces with DNA biomarker for drug delivery.

• Alternative capping agent for Biomolecules attachment.

• Silver nanaoparticles with biological synthones for gene delivery.

Our Laboratory at BU

Thank You