Flora-Glad Chizoba Ekezie
NANOTECHNOLOGY IN THE
History of Nanotechnology
Approaches to Nanotechnology.
Types of Nanomaterials and Nanostructures
Study of Phenomena and manipulation of materials at atomic, molecular and
macromolecular scale and macromolecular scales. Here, properties differ
significantly from those at larger scale.
Involves the characterization, fabrication and/or manipulation of structures,
devices or materials that have at least dimension approximately 1- 100nm in
While many definitions for nanotechnology exist, the National Nanotechnology
Initiative calls it “nanotechnology” only, if it involves all of the following:
1) Research and technology development at the atomic, molecular or
macromolecular levels, in the length scale of approximately 1-100 nanometer
2) Creating and using structures, devices and systems that have novel properties
and functions because of their small and/or intermediate size.
3) Ability to control or manipulate on the atomic scale.
HISTORY OF NANOTECHNOLOGY
FATHER OF NANOTECHNOLOGY
“There’s plenty room at the bottom”
December 29, 1959
Nobel Prize in Physics, 1965
1974, Nario Taniguchi uses the term
1985, Buckyball discovered. (Harry Koto won 1996 Nobel
prize in chemistry along with Richard Smalley and Robert Curl.
1986, K. Eric Drexler developed and popularized the
concept of Nanotechnology and founded
the field Molecular Nanotechnology.
Approaches to Nanotechnology
There are two approaches of nanotechnology applications:
1) Top-Down Approach: Involves processes such as cutting, carving. The
approach entails taking a chuck of material and removing chucks of it. E.g. By
grinding or by dissolving with acids until final product is achieved.
2) Bottom-up Approach: Involves building complex systems by combining
small atomic-level components. It starts with constituent often gases or liquid
and uses chemical, electrical or physical forces to build a nanomaterial atom by
atom or molecule by molecule.
Types of Nanomaterials and nanostructures
There are different nanomaterials, produced by the two approaches and peculiar
benefits to the Food industry. Of particular interest are engineered nanoparticles
(ENPs). The various types of ENPs include:
A. Inorganic nanomaterials:
These include ENMs of transition metals such as silver, iron; alkaline earth
metals such as calcium and magnesium; and non-metals such as selenium and
Other ENMs include titanium oxide, zinc and copper oxide. Their application in
the food industry are majorly in packaging were characteristic such as U.V
protection, mechanical strength, surface coating and processing aid, is utilized.
B. Surface Functionalized nanomaterials
Surface functionalized nanomaterials are the second-generation ENMs that add
certain types of functionality to the matrix such as antimicrobial, antioxidant or a
They are used to bind to polymer matrix to offer mechanical strength or a barrier
to movement of gases. They are more likely to react with different food
components or became bound to food matrices.
A typical example is functionalized nano-clays in food packaging to develop
materials with enhanced gas barrier properties.
C. Organic nanomaterials
These include substances encapsulated in nano-delivery systems. Examples
include vitamins, antioxidants, colours, flavours and preservatives.
The main principle behind the development of nano-sized organic substances is
their increased uptake, absorption and improved bioavailability in the body,
compared with conventional bulk equivalents.
An example of an organic nanomaterial is the tomato carotenoid lycopene.
Canola active oil is an Israel product Technology which is a development of
minute compressed micelles that allows penetration of healthy components that
are insoluble in water or fat.
Types of Nanostructures
It is defined as a technology used to pack substances in miniature, making use of
techniques such as nanocomposites, nanoemulsification and provide final
product functionality that include controlled release of the core.
Examples includes bioactive compounds such as vitamins, antioxidants, protein
and lipids as well as carbohydrates.
The main advantage is said to be better dispensability of water insoluble
additives in foodstuffs without the use of additional fats or surfactants and also
enhanced tastes and flavours.
They are a class of extremely small droplets in the range of 50 to 100nm that
appear transparent or translucent. They contain the continuous phase, dispersed
phase and surfactant.
The nanosizes of emulsions enhance not only stability of the emulsion but also
the bioavailability of the encapsulated phytochemicals.
Applications include decontamination of packaging equipment, removal of
pesticide residues from fruits and vegetables, removal of oil and dirt from
cutlery, inclusion in berages e.t.c
These are materials in which filler has at least one dimension smaller than
100nm. Nanocomposites can improve mechanical strength; reduce weight;
increase heat resistance and improve barrier against oxygen, carbon dioxide
The various types include a) Polymer nanocomposites which are thermoplastic
polymers that have nanoscale inclusions, 2-8 % by weight e.g. Nano-clay,
carbon nanoparticles, nanoscale metals e.t.c.
And b) Bio-based nanocomposites in which plant materials ( starch, cellulose,
proteins other polysaccharides e.t.c) are used. However they have poor
mechanical and barrier properties but can be augmented by incorporating
inorganic nanoparticles. E.g. Bayer polymers contain silicate nanoparticles.
Carbon Nanotubes (also known as buckytubes) are allotropes of carbon with a
cylindrical nanostructure. They are members of the fullerene structural family,
which also includes these spehrical buckyballs.
Nanotubes can be categorized as single-walled nanotubes (SWNTs) and multi-
walled nanotubes (MWNTs).
Major application area of application in the food industry is packaging.
Food Packaging Applications
Food packaging is considered to be one of the earliest commercial applications
of nanotechnology in the food sector.
About 400-500 nano-packaging products are estimated to be in commercial use
at the moment, while nanotechnology is predicted to be used in the manufacture
of 25% of all food packaging within the next decade.
1. Polymer nanocomposites
Incorporating nanomaterials into the packaging polymer to improve
physical performance, durability, barrier properties and
biodegradation ( Bradley, 2011).
Polymer matrix + Nanomaterials = PNCs
Polymers used in Food packaging
Polyethylene (HDPE, LDPE,
2. Polyethlene terephthalate(PET)
4. Polyvinyl chloride (PVC)
Strength and stiffness
Barrier to oxygen and
Resistance to food
PET provides a good barrier to oxygen (O2 permeability = 6-8 nmol/m1s1
GPa1) but highly permeable for water vapour.
Density polyethylene (HDPE) fares much worse (O2 permeability = 2000-4000
nmol/m1 s1 GPa1) but HDPE offers a significantly better barrier properties
agasint water vapor than PET.
In some applications, high barriers to migration or gas diffusion are undesirable
(E.g. fresh fruits and vegetables)
High oxygen and carbon dioxide barriers is necessary (E.G. Plastics utilized for
carbonated beverages containers).
(Finnigan et al., 2009)
Advantages of Polymer based nanocomposites
1. Enhanced polymer barrier properties
3. More flame resistant
4. Possess better thermal properties e.g Melting point, degradation and glass
5. Alteration in surface wettability and hydrophobicity.
Incorporating nanomaterials onto the packaging surface (either the inside or the
outside surface, or a sandwitched as a layer in a laminate) to improve especially
the barrier properties.
Using nano-thin coatings (Polymer + nanoparticles ) can help improve enhanced
Vaccum-deposited aluminium coatings on plastic films
Coating of the surfaces of glass food and beverages containers (Bottles, jars) with
Example: Nanosilica coated high oxygen barrier films
Excellent oxygen and moisture barrier.
Shelf life of packaged food increase and
hence, production cost reduces.
Good printability and laminating
Transparent and Eco-friendly.
Time invariant transparency
Excellent mechanical and optical
3. Surface Biocides
Incorporating nanomaterials with antimicrobial properties on the surface of the
Used to maintain hygienic condition of the food contact surface by preventing or
reducing microbial growth and helping cleanability.
Common in some reusable food containers such as boxes and crates and inside
liners of refrigerators and freezers also.
Have a high ratio of surface area to mass
Chemicals commonly used are Nanosilver, zinc, magnesium and titanum
Antimicrobial activity of nanoparticles
Their activity is related to several mechanism:
1. Directly interact with the microbial cells:
a. Interpreting trans-membrane electron transfer
b. Disrupting/penetrating the cell envelope
c. Oxidizing cell components
2. By producing secondary metabolites
a. Reactive oxygen species (ROS)
b. Dissolved heavy metal ions.
(Li et al., 2008)
4. Active Nano-packaging
Incorporating nanomaterials with antimicrobial or other properties (e.g antioxidant)
with intentional release into and consequent effect on the package d food. Examples:
1. Antimicrobial agents like AgNps, magnesium oxide, copper and copper oxide,
zinc oxide, calcium selenide/telluride, chitosan and carbon nano-tubes are used.
Ultrasonically dispersed TiO2 nanoparticles throughout EVOH films and observed
their effective photoactivated biocidal properties against microorganisms (bacteria
AgNPs being incorporated into cellulose pads for use in modified atmosphere
2) Oxygen Scavenging materials
Food deterioration by indirect action of O2 includes food spoilage by aerobic
Oxygen scavenger films were successfully developed by Xiao et al ., 2004 by
adding titanium Nps to different polymers.
Iron-based nanoclay with LDPE, HDPE, PET
5. Intelligent packaging
Incorporating nano-sensors to monitor and report on the condition of the
They are able to respond to environmental changes inside the package
(Temperature, humidity and level of oxygen exposure)
Nano-sensors communicate the degradation of product or microbial
contamination (Bouwmeester et al., 2009)
Also give the history of storage and period of storage. Nano-sensors can detect
certain chemical compounds, pathogens and toxins in food.
Eliminate the need for inaccurate expiration dates.
Provide real-time status of Food freshness e.g Ripesense, onvu
Examples of Nanosensors in Packaging
1. Noninvasive gas sensors (Mill et al., 2005)
Photo-activated indicator ink for in-package oxygen detection based upon
Nanosized TiO2 and SnO2 particles and a redox-active dye(methylene blue).
2. Sensors for moisture content (Luechinger et al., 2007)
Based upon carbon coated copper nanoparticles dispersed in a tenside film.
3. Carbon dioxide content in MAPs (McEboy et al., 2002)
Based upon analysis of luminescent dyes standardized by flourophore
encapsulated polymer nanoparticles.
Biodegrable polymers which meet all criteria of scientifically recognized norms for
biodegradability and compostability.
Renewable biomass source such as vegetable oil, corn-starch, potato-starch or
microbes, rather than fossil fuel plastics which are derived from petroleum.
Increase the gas and vapour barrier properties
Increase the mechanical strength
Efficient antioxidant, oxygen scavenging or antimicrobial bio packaging
Increase foods quality and safety.
APPLICATON OF NANOTECHNOLOGY IN
During food processing, nanoparticles have been applied to improve nutritional
quality, flow properties, flavor, color and stability or to increase shelf life.
Indeed, nanotechnology might help in development of healthier food with lower
fat, sugar and salts to overcome many food-related diseases.
Recently, bulk amounts of SiO2 and TiO2 oxides have been permitted as food
additives (E551 and E171,respectively) (EFSA, 2000).
Effective olive oil hydrolysis by the use of covalent immobilization of porcine
triacylglycerol lipase onto functionalized nanoscale SiO2 with reactive aldehyde
group for better reuse, adaptation and stability have also been reported (Bai et
Several nano and micro-structured assemblies of nanoparticles have bee
designed for encapsulation of food ingredients, additives, nutritional
Interactive foods and beverages give desired flavors ad colours (on-demand
delivery) by the addition of Nano capsules which burst at different microwave
U.S nanotechnology center has explored the application of nanotechnology for
water purification and treatment focusing on membrane and membrane
Nanotubes made of milk protein by self-assembly have potential to be used as
novel ingredients for viscofying, gelation and nanoencapsulation controlled
Applicationf of Nanotechnology in Nutraceutical
The potential of nanotechnology in functional food, design of nutritional
supplements and nutraceuticals containing nanosized ingredients and additives
such as; vitamins, antimicrobials, antioxidants, and preservatives are currently
available for enhanced taste, absorption and bioavailability (Momin et al., 2013).
Some nutraceuticals incorporated in the carriers include lycopene, beta-carotenes
and phytosterols are used in healthy foods to prevent the accumulation of
cholesterol (Mozafari et al., 2006).
Whey proteins nanospheres(40nm), which are internalized by cells and degraded
therein to release the nutraceutical compounds, can be used as carriers for oral
administration of nutraceutical agents to improve their bioavailability.
Application of Nanotechnology in Food
Microbiology and Food Safety
Detection of very small amounts of chemical contaminants, viruses and bacteria
is another application of nanotechnology.
Food pathogens can be detected using nano-flourescent particles manufactured
out of magnetic materials .
Chip based sensing is another new area for rapid detection of biological
pathogens with tremendous potential in early warning regarding exposure to air
The biosensors can be incorporated to alert consumers, producers and
distributors against safety status of the processing product.
Examples of foods, food packaging and agriculture
products that contain nanomaterials
Nanotechnology, nano-science and nano-biotechnology are
concerned with the understanding and rational manipulation
of materials at the atomic and molecular levels.
In its widest sense, nanotechnology is a natural part of food
processing and conventional foods because the
characteristic properties of many foods rely on nanometre
As developments in nanotechnology continue to emerge, its
applicability to the food industry will increase potentially.
Buonocore, G. G., Conte, A., Corbo, M. R., Sinigaglia, M., & Del Nobile., M. A.
(2005). Mono- and multilayer active films containing lysozyme as antimicrobial
agent. Innovative Food Science and Emerging Technologies, 6, 459–464.
Burdo, O. (2005). Nanoscale effects in food production technologies. Journal of
Engineering Physics and Thermophysics, 78(1), 90–97.
Chaudhry, Q., Scotter, M., Blackburn, J., Ross, B., Boxall, A., Castle, L., et al.
(2008). Applications and implications of nanotechnologies for the food sector. Food
Additives and Contaminants, 25(3), 241–258.
Fernandez, A., Torres-Giner, S., & Lagaron, J. M. (2009). Novel route to
stabilization of bioactive antioxidants by encapsulation in electrospun fibers of zein
prolamine. Food Hydrocolloids, 23(5),1427–1432.
Neethirajan, S., & Jayas, D. S. (2007). Sensors for grain storage. In: 2007
ASABE Annual International Meeting, 17-20 June 2007, Minneapolis, USA.