Vaibhav Kumar Maurya
Richard Feynman (1959) laid foundation
step of nanotechnology in his lecture on
“there is plenty of room at the bottom”.
Term was given by Nario Taniguchi and
popularized by Drexler
Nano means dwarf (Greek word “nanos”).
Defination: The manipulation of matter
with at –least one dimension sized
between 1 to 100 nanometers (by National
A Nanometre is a unit of length in the
metric system, equal to one billionth of a
Technology is the making, usage, and knowledge of tools, machines and
techniques, in order to solve a problem or perform a specific function.
Nanoparticle characterization is necessary to establish understanding
and control of nanoparticle synthesis and applications.
Characterization is done by using a variety of different techniques like:
Scanning Tunneling microscope (STM) are scanning probes
Atomic force microscopy (AFM)
Electron microscopy (TEM, SEM)
Dynamic light scattering (DLS)
X-ray photoelectron spectroscopy (XPS)
Powder X-ray diffraction (XRD)
Fourier transform infrared spectroscopy (FTIR)
Matrix-assisted laser description/ionization time-of-flight mass
Dual polarisation interferometry and
Nuclear magnetic resonance (NMR)
Synthesis of Nanomaterials
In the bottom-up approach, molecular components arrange themselves
into more complex assemblies atom-by-atom, molecule-by-molecule,
cluster-by cluster from the bottom (e.g., growth of a crystal).
Molecular components arrange themselves into some useful
conformation using the concept of molecular self-assembly.
For example, synthesis of nanoparticles by colloid dispersions.
In this approach,
are created by
to direct their
The top-down approach often uses the traditional workshop or micro-
fabrication methods in which externally-controlled tools are used to cut,
mill and shape materials into the desired shape and order.
Attrition and milling for making nanoparticles are typical top-down
Both the techniques i.e., bottom-up and top-down are employed.
Lithography is an example in which the growth of thin film is a bottom-
up method whereas itching is a top-down method.
Nanoparticles are synthesize using techniques such as ultraviolet
irradiation, aerosol technologies, lithography, laser ablation, ultrasonic
fields and photochemical reduction techniques.
Disadvantages: Expensive and involve use of hazardous chemicals.
Green synthesis: make use of biological systems (microbial sysnthesis)
Disadvantages: low monodispersity, low production rates and high
Structure of Nanomaterials
Classified by their dimensions:
Zero-dimensional nanostructures – nanoparticles
One-dimensional nanostructures – whiskers, fibers (or fibrils),
nanowires, nanorods, nanocables and nanotubes
Two-dimensional nanostructures – thin films
Three-dimensional nanostructures – colloids bearing complex shapes
Carbon Nanotubes (CNT)
Tubular form of carbon
- Diameter - as small as 1nm
- Length – few nm to microns
Configuration is similar to 2D graphene
sheets rolled in a tube.
Two types of carbon nanotubes:
1. Single wall Nanotubes (SWNT): made up of single rolled graphene layer,
difficult to synthesize in pure, defect-free form. It accumulates less in the
body, hence used for biomedical purposes.
2. Multi wall Nanotubes (MWNT): made of bunch of graphene layers rolled
together. Bulk synthesis is easy, high purity is attained. It accumulates
more in the body.
Helps in creating light weight spacecrafts.
Easily penetrate membranes such as cell walls – helps in cancer detection
Helps in developing sensors that can detect chemical vapours.
Fabrication of gene chip can be done – used for environmental monitoring
and pathogen detection.
Difficult to produce in bulk, maintaining homogeneity and purity.
It’s scarcely soluble in water – can be overcome by fictionalization.
Quantum Dots (Nanorods)
A crystalline nanoparticle made of semiconductor material, small
enough to show quantum mechanical properties.
Dimensions range from 1-100 nm.
Electronic properties are intermediary of bulk semiconductor and
They are closely related to their shape and size, the size is inversely
proportional to band gap.
Made from range of materials – zinc sulphide, lead sulphide, cadmium
selenide, and indium phosphide.
Can be toxic while using in human body therefore coated with a
Detection of toxins and pathogens, and defining their characteristics
including virulence. Examples of pathogens targeted so far:
Cryptosporidium parvum, Giardia lamblia, Escherichia coli
0157:H7, Salmonella Typhi and Listeria monocytogenes.
Used in display technologies.
Used in micro-electromechanical systems (MEMS).
Used in cancer therapeutics.
Nanowires (Quantum Wires)
Extremely thin wire
- Thickness or diameter = ≤ 10-9m.
- Aspect ratio (length-to-width ratio) = ≥ 1000
Development of microprocessors, prototype sensors and nanobots.
Used for bio-sensing purposes.
Nanowire based devices are ultrasensitive and thus can detect wide
range of biological and chemical species from DNA to drug molecules
and viruses and pH.
Can detect the presence of altered genes associated with cancer and
even determine the exact location of the mutation.
Produced from a variety of polymers like nylon, polystyrene,
polyacrylonitrile, polycarbonate and water soluble polymers.
Generally not used as a single fiber thus, layered as a sheet or mat.
Properties: Low density, large surface area to mass, high pore volume,
small pore size, superior mechanical properties and possibility to
incorporate different additives.
Peptide nanofibers associates to form nanofiber scaffold with well-
ordered nanopores - ideal material for 3D cell culture of artificial
organs, or tissues, controlled cell differentiation, regenerative medicine,
wound healing and slow drug delivery applications.
Used to make sensors to detect chemical agents; filters for air, water,
beverage, oil and fuel purification; lightweight clothing; better
efficiency batteries and food packaging.
Nanobiosystems, Medical, and Health Applications
Enhanced biological imaging for medical diagnostics (Quantum
Early diagnosis of atherosclerosis or the build up of plaque in
Detection of early-stage Alzheimer’s disease (Gold particles).
Detect rare molecular signals associated with malignancy.
Nanotechnology enables delivery of agriculture chemicals
(fertilizers, pesticides, herbicides, plant growth regulators etc).
Field sensing system to monitor the environmental stresses and crop
Nanotechnology enables the study of plant disease mechanisms.
Improving plant traits against environmental stresses and diseases.
Electronics and Information technology Applications
Magnetic random access memory (MRAM) enabled by
nanometer‐scale magnetic tunnel junctions.
Displays for electronic items incorporate
nanostructured polymer films known as
organic light-emitting diodes (OLEDs).
Flash memory chips for iPod nanos.
Ultraresponsive hearing aids.
Morph, a nanotechnology concept
device developed by Nokia Research
Center (NKC) and the University of
Antimicrobial/antibacterial coatings on mouse/keyboard/cell phone
Conductive inks for printed electronics for RFID/smart cards/smart
More life-like video games.
Flexible displays for e-book readers.
Sustainable Energy Applications
Prototype solar panels.
Improved efficiency of fuel production and consumption.
Nano-bioengineering of enzymes.
Conversion of waste heat in computers, automobiles, homes,
power plants, etc., to usable electrical power.
An epoxy containing carbon nanotubes - used to make windmill
Nanostructured materials - to improve hydrogen membrane and
storage materials and the catalysts needed to realize fuel cells for
alternative transportation technologies at reduced cost.
Low-friction nano-engineered lubricants for all kinds of higher-
efficiency machine gears, pumps, and fans.
More efficient lighting systems in advanced electronics.
Light-responsive smart coatings for glass to complement alternative
High-light-intensity, fast-recharging lanterns for emergency crews.
Environmental Remediation Applications
Lighter cars and machinery requiring less fuel or alternative fuel and
Affordable, clean drinking water.
Nanofabric "paper towel”.
Many airplane cabin and other types of air filters are nanotechnology-
based filters that allow “mechanical filtration”.
New nanotechnology-enabled sensors - to detect, identify, and filter out,
and/or neutralize harmful chemical or biological agents in the air and
soil with much higher sensitivity than is possible today.
800 commercial products rely on nanoscale materials and processes (NNI).
Nanoscale additives used in polymer composite materials for baseball bats,
tennis rackets, motorcycle helmets, automobile bumpers, luggage, and
power tool housings.
Fabrics - resist wrinkling, staining, and bacterial growth, and provide
lightweight ballistic energy deflection in personal body armor.
Nanoscale thin films on eyeglasses, computer and camera displays,
windows, and other surfaces.
Nano-engineered materials in the food industry include nanoencapsulation,
nanocomposites in food containers.
Nanosensors built into plastic packaging - warns against spoiled food.
Nanosensors - to detect salmonella, pesticides, and other contaminates
on food before packaging and distribution.
Nano-engineered materials in automotive products:
– high-power rechargeable battery systems;
– thermoelectric materials for temperature control;
– lower-rolling-resistance tires;
– high-efficiency/low-cost sensors and electronics;
– thin-film smart solar panels; and
– fuel additives and improved catalytic converters for cleaner exhaust and
Nano-engineered materials make superior household products.
Nanostructured ceramic coatings.
Nanoparticles are used in catalysis to boost chemical reactions. -
petroleum refining and in automotive catalytic converters.
Silver nanocrystals embedded in bandages to kill bacteria and prevent
Nanoparticulate-based synthetic bone: formed by manipulating calcium
and phosphate at the molecular level.
Aerogels lightest known solid due to good insulating properties is used
in space units and are proposed to use in space craft.
Nanotechnology in INDIA
IIT Mumbai is the premier organization in the field of nanotehcnology.
Institute of Nano-science and Technology (INST), Mohali.
Research in the field of health, environment, medicines are still on.
Starting in 2001 the Government of India launched the Nano Science and
Technology Initiative (NSTI).
In 2007 the Nanoscience and Technology Mission 2007 was initiated for a period
of five years.
The main objectives of the Nano Mission are:
Basic research promotion.
Infrastructure development for carrying out front-ranking research.
Development of nano technologies and their applications.
Human resource development and
Researchers are developing wires containing carbon nanotubes to have
much lower resistance than the high-tension wires currently used in the
electric grid and thus reduce transmission power loss.
To power mobile electronic devices, researchers are developing thin-film
solar electric panels that can be fitted onto computer cases and flexible
piezoelectric nanowires woven into clothing to generate usable energy
on-the-go from light, friction, and/or body heat.
Researchers are investigating carbon nanotube “scrubbers,” and
membranes to separate carbon dioxide from power plant exhaust.
Researchers are investigating particles such as self-assembled
monolayers on mesoporous supports (SAMMS™), dendrimers, carbon
nanotubes, and metallo-porphyrinogens.
Nanoparticles will in future be used to clean industrial water pollutants
in ground water.
The future of nanotechnology could include the use of nanorobotics.
These nanorobots have the potential to take on human tasks as well as
tasks that humans could never complete. The rebuilding of the depleted
ozone layer could potentially be able to be performed.
There would be an entire nano surgical field to help cure everything
from natural aging to diabetes to bone spurs.
There would be almost nothing that couldn’t be repaired (eventually)
with the introduction of nano surgery.
Pitfalls of Nanotechnology
Nano-particles can get into the body through the skin, lungs, and digestive
system, thus creating free radicals that can cause cell damage.
Once nano-particles are in the bloodstream, they will be able to cross the
Nanobots because of their replicating behavior can
be big threat to GRAY GOO.
The most dangerous Nano-application use for
millitary purposes is the Nano-bomb that contain
engineered self multiplying deadly viruses that can
continue to wipe out a community, country or even a
Is Nanotechnology boon or bane for the society. Comment.
What could be the future applications or outcomes of
Chen, H., and Yada, R. (2011). Nanotechnologies in agriculture:
New tools for sustainable development. Trends in Food Science
and Technology. 22, 585-594.