The Presence of Nanoparticles in Food Product and the...
Transcript of The Presence of Nanoparticles in Food Product and the...
The Presence of
Nanoparticles in Food Product
and
the Challenge in
Sample Preparation and Detection
WANG Zheng Ming
AVA
Spectroscopy Solutions 2014 eConference
May 2014
Presentation Summary
-General nanotechnology: development and application
-Nanotechnology and agro/food products
-Presence of nanoparticles (NPs) in food products
-Human exposure of ENPs through food products
-Analytical methods and techniques
-Examples: analysing ENPs in complex matrix
-Conclusion
Passive Nanostructures
● Nanoparticle ● Polymers ● Nanocoatings ● Nanostructured metals
Active Nanostructures ● Amplifiers ● Sensors ● Targeted drugs ● Adaptive structures
Nanosystems
● Guided assembling ● 3D Networks & new hierarchical architectures ● Robotics
Molecular Nanosystems
● Molecule device by design ● Atomic design; ● Emerging functions
Nanotechnology – Development and Applications
Yesterday Today & Tomorrow
Adopted from MC Roco. AIChEJ 50:890 (2004)
2000 2010 2020
4. Gen
3. Gen 2. Gen
1. Gen
today
Converging Technologies
● Nano-bio-info from nanoscale ● Cognitive technologies; ● Large complex systems (nanoscale)
Year
Advanced Nanotechnology & Consumer Products
Today
MC Roco (2011) J Nanopart Res 13:427–445
On scale, this tennis ball is the
same size in relation to earth
as a nanoparticle is to a tennis ball.
Info from: http://nanohex.org/flash/Nano_What.html
Head of pin 1 millimetre
Red Blood Cell 2.5 micrometers
Ragweed pollen 20 micrometers
Carbon nanotube 2 nanometers
= 1,000,000 nanometers = 2,500 nanometers = 20,000 nanometers = 2 nanometers
Generally, nanotechnology deals with
structures sized between 1 and 100 nm
in at least one dimension. Guidance on the risk assessment of the application of nanoscience and nanotechnologies in the food and feed chain. EFSA Journal 2011;9(5):2140
Engineered Nanoparticles (ENPs).
Different forms substances, shapes, & sizes.
Particles, / Rods, Fibres and Tubes / Sheets / Composites / Aggregates,
Agglomerates, Encapsulates, etc…
Unique physicochemical properties:
-high surface-to-mass ratio and surface reactivity;
-they are expected to interact with substances such as proteins, lipids,
carbohydrates, nucleic acids, ions, minerals and water present in
food and biological tissues;
Some ENPs are designed to cross the blood-brain barrier PNAS (2011) 108(46):18837-42 J Control Release. (2012) 161(2):264-73 J Drug Target. (2004) 12(9-10):635-41
-Cosmetics and personal care products;
-Paint and Coating;
-Catalysis & Lubricants;
- Security printing;
-Textiles and sports;
-Food and nutritional supplements;
-Food packaging;
-Agrochemical;
-Construction materials;
- Fuel Cell & batteries;
-Paper manufacturing;
-Water decontamination;
-Others
Woodrow Wilson Databank, http://www.nanotechproject.org/cpi/
Nanotech & medicine
Consumer Products Using
Nanotech Applications
9.3 billion
6.9 billion
Source: UN, Department of Economic and Social Affairs, Population Division(2011)
Year Po
pu
lati
on
(b
illio
ns)
-world population
-meat consumption
-available crop land
-water tables
-climate change
Food Security Agro Technology
Food Science and Technology
Food production must increase
70-100% (FAO 2009 estimation)
Nanotechnology
Nanotechnology and Agro/food products
World Population Growth
Application of Nanotechnology in Agriculture Sectors
maximizing crop yields (output), minimizing input (i.e. pesticides, fertilizers, and
herbicides, etc) through efficient monitoring environmental variables and
applying targeted action, also improve soil sustainability
System Component:
1) remote smart / nano sensors for real time crop development, soil condition, usage
of agro-chemicals, seeding, etc… 2) GPS; 3) IT system and 4) controlled release
Nanoforum Report (2006): Nanotechnology in Agriculture and Food
Precision farming
Nanosystem
Application of Nanotechnology In Food Products
Application Nanotechnology Function Nano-textured food
ingredients
Processed nano-structures
in food Novel or improved tastes, flavours,
textures
Nano-delivery
systems for nutrients
/ supplements
Nano-encapsulated
bioactive substances –
mainly additives and
supplements
Nanocarrier systems used for taste
masking of ingredients / additives
i.e. fish oils, protection from
degradation.
Organic & Inorganic
nano-sized
additives for food
manufactured in the
nanosize range Due to larger surface area, smaller
quantity would be needed.
-Surface
functionalized nano
materials
-Nano-coatings on
food contact
surfaces
-2nd gen ENPs add
functionality to the matrix,
i.e. antimicrobial activity via
O2 absorption.
-Nanoscale coating.
-functionalized ENPs to bind the
polymer matrix, provide a barrier
against volatile flavours or moisture
movement,
- Nanocoatings for FCMs with
barrier or antimicrobial properties.
modified from 1) FAO/WHO (Nov. 2012) State of the art on the initiatives and activities relevant to risk assessment and risk management of nanotechnologies in the food and agriculture sectors 2) FAO/WHO (2010). FAO/WHO expert meeting on the application of nanotechnologies in the Food and agriculture sectors. Potential food safety implications. Meeting report.
Woodrow Wilson Databank http://www.nanotechproject.org/
Food Products Examples
TiO2 (anticaking agent)
Ag (FCM)
NP Ag and NP TiO2 will be used as example for sample prep and detection later
Supply Seeds Fertilizers Feed, etc
Farm Primary Production
Processing /Packaging
Distribution Network
Retail Stores
Consumers
Nanotechnology has an impact on every aspect of the food supply chain,
from how food is cultivated, produced, processed, packaged and stored.
Food and food related products incorporating nanotechnology
include nanoscale fertilizers, pesticides, food additives,
enzymes, flavourings, and food packaging materials.
Emerging technologies governance is
essential. Human potential and
technological development are
coevolving with benefits and risks. Mike Roco,
National Science Foundation and National Nanotechnology Initiative Nanomanufacturing Summit 2011, Boston, September 27, 2011
Sustainable Development is the KEY
Food
Presence of NPs in Agriculture / Food Products
and Possible Routes of Human Exposure
Food and FCMs
Feed and Vet Drugs
Fertilizer & Pesticide
Not only direct food ingestion
Residues from agriculture and
industral production can
enter into air, water, soil, etc…
Animal Plants
Air respiratory
system
Food &
Water digestive
system
Water, soil, other contact skin and membranes
"All things are poison, and nothing is without poison;
only the dose permits something not to be
poisonous.” Paracelsus (1493-1541) [pærəˈsɛlsəs]
How much is too much?
Examples:
Salt & sugar
Nano particles ???
Father of the toxicology
The need for characterization & quantification
Fadeel & Garcia-Bennett (2010)
Adv Drug Del Rev 62:362
risk =
haza
rd x
exp
osu
re
Risk Assessment Paradigm is Applicable
Challenges
complexity
dynamics
trans-disciplinarity
uncertainty
Challenges
Food Product Application Specific
Challenges
Nanotech Development and its Application in General
Both are interconnected
Characterization of ENPs in five stages: (1) Pristine state (as manufactured);
(2) As delivered to be used in food/feed;
(3) As present in food/feed matrix;
(4) As present in biological matrices;
(5) As toxicological tested;
ENPs in Food Matrix -dynamic interaction of ENPs with food matrix constituents
-aggregation due to food matrix environment,
-broad variety of matrices (raw and processed food)
(influence their sample preparation, detection, and risk assessment)
Do we have the comprehensive knowledge?
-Limited practical RA experiences in the food/feed areas
-RA on a case by case basis (EFSA)
-Data for long term / low dose exposure missing
-Info on shorter term exposure not reliable
-International harmonization needs
Risk assessment
Ch
allen
ge
s
Environ. Sci. Technol.
2012, 46, 2242
Complexity in exposure consideration
-Globalized food supply chains: Ingredient of food products can come
from different regions (cottonseed oil and olive oil)
-Exposure to food and water with incidental nanomaterials may
have high risk
-TiO2 – E171 Not specifically labelled as nanosized. However,….….
-Bioaccumulating and persistent NPs likely end
up in the food / feed chain as contaminants
-Nano applications and organic food
Very little dietary information,
especially toxicokinetic
information, is available for
Nanoparticles -- Uncertainty
Legislation & Labelling : Synchronized and Asynchronous
Ch
allen
ge
s
The development of analytical techniques
is a key to understand
the benefits as well
as the risks
of the application
Of nano materials in food products
Ch
all
en
ge
s
Size and size distribution NPs defined and classed by their size, the primary properties
describing transport behaviour
Morphology and shape It affects NPs’ surface areas and surface-to-mass ratio, it also
can posses different affinities or accessibilities
Elemental composition different particle composition different behaviour, toxicity,
impact
Mass concentration normally it correlates its toxicity/impact, but this is not always
applicable for NPs;
Particle number NPs have low mass concentrations, but show high percentage
of total particle numbers
Aggregation state NPs have a tendency to aggregate, increase in size could lead
to decrease in uptake
Surface area (e.g. porosity) Increase in surface area, reactivity and absorption behaviour
Surface charge influence on particle stability especially in dispersions
Surface chemistry Coatings can consist of different chemical compositions and
influence particle behaviour or toxicity
Solubility soluble NPs, their ionic form can be harmful or toxic
Structure The structure can influence stability or behaviour
Characterisation Parameters of
ENPs used in food products
Modified from Tiede at al. 2008. Food Additives and Contaminants 25(7) 795–821
Nanoparticles, aggregates and agglomerates
primary particle (pristine)
agglomerated primary particles
aggregated primary particles
Adopted from Peters and Bouwmeester of RIKILT
Different sample preparation for sample contains NPs’ aggregates and
agglomerates will affect the detection outcome.
Analytical methods for NPs characterization
Modified from Tiede at al. 2008. Food Additives and Contaminants 25(7) 795–821
Microscopy related techniques STEM, TEM, SEM : size, size distribution, Morphology /shape, aggregation,
structure,
AEM, CFM: mass concentration, surface chemistry SEM/TEM
ICP-MS
Elemental analysis / quantification
(metal / metaloxide NPs)
Field-Flow Fractionation
Separation / fractionation
Chromatography related techniques HDC, FFF: size distribution
ICP-MS: elemental analysis (quantitative)
Analytical methods for NPs characterization
Modified from Tiede at al.
2008. Food Additives and
Contaminants 25(7) 795–821
Spectroscopic related techniques NMR: chemical composition
XRD: aggregation, chemical composition, elemental analysis,
structure,
Centrifugation & filtration techniques UC, CFF: size distribution
Other techniques Zeta potential: surface charge, aggregation
BET: surface area & porosity
physicochemical characterisation of ENPs will need
different analytical methods
STEM: scanning transmission electron microscopy
TEM: transmission electron microscopy
SEM: scanning electron microscopy
AEM: analytical electron microscopy
CFM: chemical force microscopy
HDC: hydrodynamic chromatography
FFF: field-flow fractionation
ICP-MS: Inductively coupled plasma- Mass spectrometry
NMR: Nuclear magnetic resonance
XRD: X-ray diffraction
UC: Ultracentrifugation
CFF: Cross flow filtration
BET: runauer–Emmett–Teller
Ab
bre
via
tion
Common Analytical Approach
Food safety tests
-Presence
-Identity chemical composition & size distribution
-Concentration mass & particle number
Screening: e,g, Image technique / in matrix, better suit for
heavy elements, special sample prep, automated imaging
analysis
Confirmatory methods: e.g. FFF on-line coupling ICP-MS
quantification
unambiguous identification
[sample prep: extract NPs from sample matrix,
removal interfering matrix component
enrichment of targeted analytes]
Examples 1
Development and validation of single particle ICP-MS
for sizing and quantitative determination of nano-silver
in chicken meat Anal Bioanal Chem. 2014 Jan 5. [Epub ahead of print] Ruud J. B. Peters & Zahira Herrera Rivera & Greet van Bemmel & Hans J. P. Marvin & Stefan Weigel & Hans Bouwmeester RIKILT, Wageningen University Research, The Netherlands
A method is developed and
validated for sizing and
quantifying NP Ag in
chicken meat using SP ICP-MS
-chicken meat purchased from local supermarket.
-200mg subsample, cut into small pieces, placed into a 10mL PE tube.
-the subsample in the tube was fortified with a 50mg/L aqueous
suspension of the 60nm Ag NPs at 5, 10, and 25 mg/kg.
-two steps enzymatic digestion
-1st, add 4 mL of the digestion buffer, vortex vigorously 1 min
tip sonication at 4W power 5 min / tube on ice.
-2nd, add 25μL of proteinase K, incubation for 3 h at 35 °C.
-cooling to room temperature,
-dilute the digest 100,000 times and measured using sp-ICP-MS.
Sample prep
Anal Bioanal Chem. 2014 Jan 5. [Epub ahead of print]
Anal Bioanal Chem. 2014 Jan 5. [Epub ahead of print]
Method validation:
repeatability, reproducibility, trueness, linearity (see below picture),
LOD/LOQ, robustness, specificity/selectivity.
Linearity demonstrated by the analyses of matrix-matched standards of 60-nm Ag NPs in the range of 0.05Vl–5VL on each of the validation days
To determine the fate of NP Ag after addition to the chicken meat.
0 hr: the digest of sample processed directly after adding NP Ag
48 hr: the digest was produced 48 h after adding the NP Ag to the sample.
EM
Anal Bioanal Chem. 2014 Jan 5. [Epub ahead of print]
EM pictures and EDX spectra of chicken digests
Anal Bioanal Chem. 2014 Jan 5. [Epub ahead of print]
The EDX spectra show that
pure silver is partly transformed
into silver sulfide
Characterisation of TiO2 NPs in sunscreens
using FFF on-line coupled ICP-MS
Heidi Goenaga-Infante’s group @ LGC Limited
J. Anal. At. Spectrom., 2012, 27, 1084 E
xam
ple
s 2
A. Contado & Pagnoni (2008) Anal. Chem. 80, 7594
B. Samontha et al. (2011) Anal. Bioanal. Chem. 399, 973
Sub-sample size 0.17–0.52 g 0.01 g
First solvent 20 mL water 1 mL hexane (defatting first)
Second solvent 20 mL methanol 1 mL water
Third solvent 10 mL hexane (defatting later) —
Defatting time 1 h phase separation 12 h, room temperature
Separation of hexane Separation funnel Not reported
Sonication Tip sonication, twice 15–60 s None
Concentration of extract
Rotary evaporation to remove methanol
None
Remarks: - More than 1 containers used -Using separation funnel -Loss of NPs to the tube walls
-Only 1 container used -No separation funnel needed
Defatting b/f NPs suspension reducing matrix interferences on the target particles
Comparison of extraction procedures
for TiO2 NPs from sunscreen
from J. Anal. At. Spectrom., 2012, 27, 1084
A. Contado & Pagnoni (2008) Anal. Chem. 80, 7594
B. Samontha et al. (2011) Anal. Bioanal. Chem. 399, 973
from J. Anal. At. Spectrom.,
2012, 27, 1084
Sample Solvent Ti [mg kg1] Ti [mg kg1] Extraction efficiency replicate 1 replicate 2 [%] (standard deviation) SPF 15 Water 36.3+ 1.8 34.7 +1.7 64.0 (0.5) SPF 30 Water 66.0 +1.8 54.3 +1.8 79 (9) SPF 50 Water 113.8 +1.7 138.3 +1.8 71 (13) SPF 15 2.5% (v/v) hexane 41.6 +1.8 33.6 +1.8 68 (8) SPF 30 2.5% (v/v) hexane 72.2 +1.8 60.5 +1.8 87 (7) SPF 50 2.5% (v/v) hexane 195.8 +1.8 195.2 +1.8 110 (5) a The weight of sunscreen was in the range of 0.1003 g to 0.1061 g for all replicates.
from J. Anal. At. Spectrom., 2012, 27, 1084
Total Ti concentration and extraction efficiency
were determined by ICP-MS
-Total Ti concentrations were determined by ICP-MS after microwave assisted digestion: 200 mg of sunscreen samples digested with a mixture of 2.5 mL nitric acid, 2.5 mL hydrogen peroxide and 0.5 mL hydrofluoric acid using a Multiwave 2000 microwave system with Teflon vessels. -Three TiO2 reference material (NIST 154c) subsamples were digested as described above. -The digests were made up to a total mass of 50 g with deionised water.
NPs TiO2 loss On tube wall
Conclusion challenges remain in NPs analytical methods for food matrix
-Diversity of NP types, combined with variety of food types / matrices
-Interaction of the NPs with food matrices, behaviour unknown
-NPs aggregation, agglomeration, affinity for surfaces – dynamic
-NPs stability, in food sample and after extraction
-Natural NPs present in food
Conclusion challenges remain in NPs analytical methods for food matrix
-Methods available for pure NPs, only few for complex matrices
-Validation of methods , identify and quantify NPs in food matrix
-Availability of Certified reference materials-well characterized and stable
-Sample preparation and recovery of NPs, uncertainty, lack of workable
standards / methods
-Necessary to have different sample preparation protocols for different
NPs added within different matrix
In real situation, usually don’t know the type of NPs present in a food
sample
-Integrated and harmonized (internationally) analytical approaches
Acknowledgement
AVA: CH’NG Ai Lee
Tze Hoong CHUA
Paul CHIEW
CHEW Siang Thai
NTU: Kee Woei NG
NUS: David LEONG
RIKILT: Ruud Peters & his colleagues
LGC: Heidi Goenaga-Infante & her colleagues
Thanks