Nanotechnology is the engineering of functional systems at the molecular scale.
The comparative size of a nanometer to a meter is the same as that of a marble to
the size of the earth. A nanometer is one billionth of a meter, roughly the width of
three or four atoms. The average human hair is about 25,000 nanometers wide.
Two main approaches are used in nanotechnology. In the "bottom-up" approach, materials and devices are
built from molecular components which assemble themselves chemically by principles of molecular
recognition. These seek to arrange smaller components into more complex assemblies.
In the "top-down" approach, nano-objects are constructed from larger entities without atomic-level control.
These seek to create smaller devices by using larger ones to direct their assembly.
popularized by Eric
representation of a
as a molecular
Branches of nanotechnology
Green nanotech – use of
nanotechnology to enhance the
processes currently producing
negative externalities. It also
refers to the use of the products
of nanotechnology to enhance
Nanoengineering– practice of
engineering on the nanoscale.
Wet nanotechnology– involves
working up to large masses from small
Nanobiotech – intersection of
nanotechnology and biology.
Two forms of
have already been
tested in mice and are
awaiting human trials
are using gold
nanoshells to help
treat cancer and
liposomes as vaccine
adjuvants and as
vehicles for drug
Nanotechnology in cancer
Nanomedical approaches to drug
delivery center on
developing nanoscale particles or
molecules to improve
Bioavailability refers to the
presence of drug molecules where
they are needed in the body and
where they will do the most good.
Drug delivery focuses on
maximizing bioavailability both at
specific places in the body and
over a period of time.
The basic point to use drug
delivery is based upon three
a) efficient encapsulation of the
b) successful delivery of said
drugs to the targeted region of
the body, and
c) successful release of that drug
Researchers at Rice
University under Prof. Jennifer
West, have demonstrated the
use of 120 nm
diameter nanoshells coated
with gold to kill cancer tumors
in mice. The nanoshells can be
targeted to bond to cancerous
conjugating antibodies or pepti
des to the nanoshell surface.
By irradiating the area of the
tumor with an infrared laser,
which passes through flesh
without heating it, the gold is
heated sufficiently to cause
death to the cancer cells.
Nanoparticles of cadmium
selenide (quantum dots)
glow when exposed to
ultraviolet light. When
injected, they seep
into cancer tumors. The
surgeon can see the
glowing tumor, and use it
as a guide for more
accurate tumor removal.
Nanomedicine would make use of
these nanorobots , introduced into
the body, to repair or detect
infections. Carbon could be the
primary element used to build these
nanorobots due to the inherent
strength and other characteristics of
some forms of carbon
(diamond/fullerene composites), and
nanorobots would be fabricated in
desktop nanofactories specialized for
With the population mounting in Asia and African regions, the global
population is expected to touch 7.5 billion by 2020 and 9 billion by 2050.
Needless to say, there is an increased need to use scientific technology
to boost agricultural production.
Nanotechnology has the potential to revolutionize the agricultural and
food industry with new tools for the molecular treatment of diseases, rapid
disease detection, enhancing the ability of plants to absorb nutrients etc.
Smart sensors and smart delivery systems will help the agricultural
industry combat viruses and other crop pathogens. In the near future
nanostructured catalysts will be available which will increase the
efficiency of pesticides and herbicides, allowing lower doses to be used
Are We Using Nano-
Biotechnology to Increase
The union of biotechnology and
nanotechnology in sensors will create
equipment of increased
sensitivity, allowing an earlier response to
environmental changes. For example:
• Nanosensors utilising carbon
nanotubes12 or nano-cantilevers13 are
small enough to trap and measure
individual proteins or even small
molecules.It seems that the
long, skinny, strawlike structures promote
water uptake, because seeds exposed to
carbon nanotubes contained more
• Nanoparticles or nanosurfaces can be
engineered to trigger an electrical or
chemical signal in the presence of a
contaminant such as bacteria.
Some nanoparticle products may have unintended consequences.
Researchers have discovered that bacteriostatic silver nanoparticles used in
socks to reduce foot odour are being released in the wash. These particles
are then flushed into the waste water stream and may destroy bacteria which
are critical components of natural ecosystems, farms, and waste treatment
Researchers have found that when rats breathed in nanoparticles, the
particles settled in the brain and lungs, which led to significant increases in
biomarkers for inflammation and stress response and that nanoparticles
induce skin aging through oxidative stress in hairless mice.
carbon nanotubes – a poster child for the “nanotechnology revolution” –
could be as harmful as asbestos if inhaled in sufficient quantities.
Is nanotechnology bad or good?
Nanotechnology offers great potential for
benefit to humankind, and also brings
severe dangers. While it is appropriate to
examine carefully the risks and possible
toxicity of nanoparticles and other products
of nanoscale technology, the greatest
hazards are posed by malicious or unwise
use of molecular manufacturing.