Download Applications of Nanotechnology in Agriculture and Food Science

Applications of Nanotechnology
in Agriculture and Food Science
Module 2
Bioe298 DP
Nanotechnology has applications in all areas of food science,
from agriculture to food processing to security to packaging to
nutrition and neutraceuticals.
Duncan, J. Colloid and Interface Sc. 2011.
‘Nano’ foods now
All foods contain nanoparticles.
Examples of foods that contain
nanoparticles include milk and meat.
Milk contains caseins, a form of milk
protein present at the nanoscale.
Meat is made up of protein filaments that
are much less than 100nm thin.
The organisation and change to the
structures of these affects the texture and
properties of the milk or meat.
Applications of nanotechnology
Uses for nanotechnology in food
Nanotechnologies are being developed all the time.
Here are some examples that are being used:
• nanocarrier systems for delivery of nutrients and
supplements;
• organic nano-sized additives for food, supplements and
animal feed;
• food packaging applications e.g. plastic polymers
containing or coated with nanomaterials for
improved mechanical or functional properties;
• nanocoatings on food contact surfaces for barrier
or antimicrobial properties;
• nano-sized agrochemicals (a chemical used in
agriculture, such as a pesticide or a fertilizer.);
• nanosensors for food labelling.
Food examples
Nanoparticles are being used to deliver vitamins or
other nutrients in food and drinks without affecting the
taste or appearance. These nanoparticles encapsulate
the nutrients and carry them through the stomach into
the bloodstream.
Nanoparticle emulsions are being used in ice cream
and various spreads to improve the texture and
uniformity.
Food examples
New developments in nanoscience and nanotechnology
will allow more control and have the potential of
increased benefits. These include:
• healthier foods (e.g. lower fat, lower salt) with
desirable sensory properties;
• ingredients with improved properties;
• potential for removal of certain additives without loss
of stability;
• smart-aids for processing foods to remove allergens
such as peanut protein.
Packaging examples
Researches have produced smart packages that can tell
consumers about the freshness of milk or meat.
When oxidation occurs in the package, nanoparticles
indicates the colour change and the consumer can see if
the product is fresh or not.
Incorporation of nanoparticles in packaging can increase
the barrier to oxygen and slow down degradation of food
during storage.
Packaging examples
Bottles made with nanocomposites minimise the leakage
of carbon dioxide out of the bottle.
This increases the shelf life of fizzy drinks without having
to use heavier glass bottles or more expensive cans.
Food storage bins have silver nanoparticles embedded
in the plastic. The silver nanoparticles kill bacteria from
any food previously stored in the bins, minimising
harmful bacteria.
Gene delivery
Momentum
Kinetic energy
Current
Charge
https://sites.google.com/site/activecarephysiotherapyclinic/parkinsons-disease
Gene Delivery
http://gene-therapy.yolasite.com/process.php
Gene Gun
• Biolistic particle delivery
system, originally designed
for plant transformation
• Device for injecting cells
with genetic information.
The
payload
is
an
elemental particle of a
heavy metal coated with
plasmid DNA.
• This technique is often
simply referred to as bioballistics or bio-listics.
Comparative study of different delivery
systems
Source: Rai,M., Deshmukh, S. , Gade, A., Elsalam, K.A. 2012 . Current Nanoscience .8 : 170-179
Vehicles for Nuclear Transformation in
Plants
Agro-bacterium mediated:
Most extensively used, wide host range (mostly
dicotyledonous)
Incompatibility between tissues of plant species
Microparticle Bombardment:
Capable of delivering DNA into nucleus, mitochondria
Cell Damage, high copy number of transgene, expensive
equipment
Electroporation:
Generate transgenic plants by protoplast transformation
Cell damage by electric pulses of wrong length, ion
imbalance and cell death
Purpose: To introduce MSN into plants
with gene gun system
Figure: Gene gun system for bombarding micro/nano particles
Source: http://swineflucaretips.blogspot.com/2012/06/dna-vaccines-and-gene-gun.html
Purpose : To deliver different biogenic species
simultaneously
• Release the encapsulated chemicals in a controlled fashion
• Generate transgenic tobacco containing inducible promoter controlled GFP
gene
• Expression of GFP observed only when chemical β-oestradiol is
present
• Transgenic plantlets bombarded with Type-IV MSNs ( filled with βoestradiol) , and pores capped with gold nanoparticles
• Release of β-oestradiol is triggered by DTT ( Dithiotheritol)
Nanoparticle Mediated Genetic
Transformation
 Nanoparticles combined with chemical
compounds deliver genes into target cells
• Decreasing the particle size from micro
to nano scale, hindrance due to cell wall
can be removed
• Cell Damage can be minimized
• The particle can reach the chloroplast
and mitochondria easily
• Different NPs used are calcium
phosphate, Carbon materials, silica,
gold magnetite, strontium phosphate.
• Enable controlled release conditions
Figure: Synthesis of mesoporous silica
Source: http://www.rmat.ceram.titech.ac.jp/research-e/mesoporus-e.html
Mesoporous silica Nanoparticles for plant cell
internalization
Experiment with MSNs – Genetic Transformation
Purpose: To investigate interaction of MSN with plant cells
Synthesize series of MSNs with different surface
functional groups/caps
Investigation of MSN in protoplasts (plant cells with
cell wall removed)
Protoplasts incubated with Type-I MSN didn’t take up
nanoparticles, Type-II MSN ( Type-I functionalized with
triethylene glycol) entered the protoplasts
• MSN system can serve as a new and versatile tool for
plant endocytosis and cell biology studies
Figure : Type-I and TypeII MSNs
Antimicrobial Activity of Silver Nanoparticles
• Silver has antibacterial properties.
However as nanoparticles the
antibacterial properties are
magnified, as the surface area to
volume ratio is increased,
allowing them to easily interact
with and fight with bacteria more
efficiently.
Silver nanoparticles
AgNPs are potent broad spectrum antimicrobials: minimum inhibitory
concentrations of 2–4 g/mL for AgNPs with diameters 45–50 nm against E. coli, V.
cholerae, S.
flexneri, and at least one strain of S. aureus, have been reported, which rivals the
bactericidal properties of penicillin against nonresistant strains.
Potency can be easily manipulated through the unique physical effects offered by
nanomaterials.
Silver nanowires are subjected to external electric fields, they have 18.5–63%
better antimicrobial potency due to enhanced silver ion production at the wire
termini.
Also, photoexcitation of AgNPs coated with a thin (1-2 nm) layer of porous silica at
visible light frequencies which are in resonance with AgNP surface plasmon bands
has been shown to enhance antimicrobial activity against E. coli significantly, either
through photosensitized ROS generation or photocatalyzed silver ion release; this
effect is also reversible, providing a portal into photo-switchable antimicrobial
behavior.
Uses of silver nanoparticles
• In refrigerators, washing machines, airconditioners, clothing, baby pacifiers, food
containers, detergent, surgical instruments,
etc.
Absorption spectra of Ag nanoparticle solutions (A). The solid line is for Ag
nanoparticle solution as prepared, the dashed one is for the ten-time concentrated
one after diluted back to the original concentration, and the dotted one is for the
solution left after the Ag nanoparticles are removed by sedimentation. The maximum
potential peaks of Ag nanoparticles were measured at -0.33mV (B). The effective
zeta-potential in aqueous solution were measured by particle characterizer bDelsa
440 SXQ (Coulter Ltd., Miami, FL), and the mean values were averaged from 3 times
assay data.
(A) A TEM image of Ag nanoparticles dispersed on a TEM copper grid (a, scale bar: 30
nm). (B) A histogram showing size distribution of Ag nanoparticles.
Growth inhibition of Ag nanoparticles against yeast. Itraconasol, distilled water, and
solution devoid of Ag stand were used for the positive control, negative control, and
vehicle control. The concentration of gold nanoparticles was 30 nM.
Antimicrobial activity of silver nanoparticles
Mechanisms of Silver Nanoparticle
Bacteriocidicity. (A and B) Silver
nanoparticles (AgNPs) are lethal to
bacteria in part because they damage cell
membranes. The figure shows pictures
from separate studies demonstrating
adherence of AgNPs to and subsequent
pitting of the membrane surface of E. coli.
(C) Due at least in part to damage of cell
membranes, the presence of AgNPs
reduces E. coli growth and viability. Here,
a photograph shows growth of E. coli on
LB plates containing AgNPs at (i) 0, (ii) 10,
(iii) 20 and (iv) 50 lgcm
3. (D) Numerous studies have explored
factors which influence AgNP lethality.
This plot relates the number of bacterial
colonies able to grow on plates incubated
with various amounts of AgNPs, as a
function of AgNP shape. Other factors
which influence AgNP antimicrobial
efficiency include particle size, surface
charge, and the nature of substituents
featured on the particles’ surfaces.
Detection of Small Organic Molecules
Problem:
An adulterant used to artificially inflate the measured protein
content of pet foods and infant formulas.
Melamine is - "Harmful if swallowed, inhaled or absorbed through
the skin. Chronic exposure may cause cancer or reproductive
damage. Eye, skin and respiratory irritant."
Solution:
The melamine-induced aggregation causes AuNPs to undergo a
reproducible, analyte-concentration-dependent color change from
red to blue, which can be used to precisely measure the melamine
content in raw milk and infant formula at concentrations as low as
2.5 ppb with the naked eye
Nanosensors and nanotechnologybased assays for food relevant analytes
(a) Schematic showing colorimetric
detection of melamine in solution using
modified gold nanoparticles (AuNPs).
AuNPs are conjugated to a cyanuric acid
derivative, which selectively binds to
melamine by hydrogen bonding
interactions. When bound to melamine,
aggregated AuNPs (blue) exhibit
different absorptive properties than
‘‘free’’ AuNPs (red). (b) Visual color
changes of AuNP-melamine sensor in
real milk samples: (1) AuNP solution
without any addition; (2) with the
addition of the extract from blank raw
milk; (3), (4) and (5) with the addition of
the extract containing 1 ppm (final
concentration: 8 ppb) melamine, 2.5
ppm (final concentration: 20 ppb)
melamine
and
5
ppm
(final
concentration: 40 ppb) melamine,
respectively.
Detection of Gasses
Photographs of O2 sensors which utilize UV-activated TiO2 Nanoparticles and methylene blue
indicator dye, one placed inside of a food package flushed with CO and one placed outside. In
(a) the package is freshly sealed and both indicators are blue. The photograph in (b) shows
the indicators immediately after activation with UVA light. After a few minutes, the indicator
outside of the package returns to a blue color, whereas the indicator in an oxygen-free
atmosphere remains white (c) until the package is opened, in which case the influx of oxygen
causes it to change back to blue (d). This system could be used to easily and noninvasively
detect the presence of leaks in every package immediately after production and at retail sites.
Moisture sensor which utilizes carbon-coated copper nanoparticles dispersed in a polymer
matrix (a). Ethanol vapor exposure results in rapid and reversible iridescent coloration (b).
Water vapor exposure swells the polymer, which causes the nanoparticles to exhibit larger
inter particle separation distances and thus different observable optical behavior (c). As
moisture dissipates (d–f), the sensor reverts back to its native state and appearance.
Reprinted with permission
IMS-based detection methods using magnetic
nanoparticles.
(a) Antibodies selective for specific
bacterial strains or species (e.g., E. coli) are
bound to the surfaces of magnetic
nanoparticles (e.g., Fe). Only the targeted
organisms will bind to the functionalized
magnetic nanoparticles. (b) A complex
matrix (e.g., food, blood, milk, etc.)
contains the target analyte as well as
numerous potential interferences, such as
other bacterial species, viruses, proteins,
food or blood particles, etc. Functionalized
magnetic nanoparticles are added to the
matrix, where they bind selectively and
with high capture efficiency to the target
analyte. A magnetic field isolates the
analyte-bound magnetic particles, after
which the supernatant is then carefully
decanted. The remaining material is then
subjected to quantification assays. In more
sophisticated systems, the magnetic
nanoparticles themselves are the means of
detection and quantification
Barrier Applications of Polymer Nanocomposites
• A critical issue in food packaging is that of migration and permeability.
• No material is completely impermeable to atmospheric gasses, water vapor, or natural
substances contained within the food being packaged or even the packaging material
itself.
• High barriers to migration or gas diffusion are undesirable, such as in packages for fresh
fruits and vegetables whose shelf life is dependent on access to a continual supply of
oxygen for sustained cellular respiration.
• Plastics utilized for carbonated beverage containers, on the other hand, must have high
oxygen and carbon dioxide barriers in order to prevent oxidation and decarbonation of
the beverage contents .
• In other products, migration of carbon dioxide is far less of an issue than that of either
oxygen or water vapor. As a result of these complexities, food products require
sophisticated and remarkably different packaging functions, and the demands on the
packaging industry will only increase as food is transported over increasingly longer
distances between producers and consumers.
Illustration of the ‘‘tortuous pathway’’ created by incorporation of exfoliated clay
nanoplatelets into a polymer matrix film. In a film composed only of polymer (a), diffusing
gas molecules on average migrate via a pathway that is perpendicular to the film
orientation. In a nanocomposite (b), diffusing molecules must navigate around
impenetrable particles/platelets and through interfacial zones which have different
permeability characteristics than those of the virgin polymer. The tortuous pathway
increases the mean gas diffusion length and, thus, the shelf-life of spoilable foods.
Conclusion
• Nanobiotechnology could take the genetic engineering of
agriculture to the next level down – atomic engineering
• Further developments such as pore enlargement and
multifunctionalization of these NPs may offer new possibilities
in target specific delivery of proteins, nucleotides and
chemicals.
• Opposition is mounting from civil society, unions and world
leading scientists who point to ecological, health and socioeconomic risks associated with nanogenetics.