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Nanotechnology

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PCQ Bureau
New Update

Imagine a technique that can work on subjects that are a thousand times

smaller than the diameter of hair! To build something productive out of these

tiny subjects is difficult, but this is what nanotechnology is all about. By

changing molecular structure of the material one can change its electrical,

chemical, and mechanical behavior. Now this is the basic principle behind

developing customized materials using nano techniques that behave in a desirable

way. The first introduction to this concept was as early as 1959, with the

actual term being used in 1974. Since then a lot has been done in this field,

but still there is tremendous scope for this technology in future. Here we would

try to define what has already been done in this field and what to expect in

future.

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Passive nanostructures



These first generation nanostructures are relatively simple and passive in

behavior. Primary products are components such as nanotubes, wires etc and with

enhanced functions and properties because of their nanostructure. Passive

nanostructures can further be categorized under two sub categories, first being

dispersed and contact surface nanostructures like nanoscale colloids, aerosols

and powders. The second category include products incorporating nanostructures

like nanoscale layers in transistors.

Here is a hypothetical nanorobot that swims through blood

vessels, this device finds its way using camera mounted in front and

contains a payload for the affected area.

Active nanostructures



These nanostructures are, as the name suggests, active in nature, ie. they

change their state according to conditions. As an example of an active

nanostructure, consider the drug delivery particles. These particles change

their morphological and chemical composition. These changes lead to a change in

the property (mechanical, electronic etc) of the nanostructure for desired

results. This category of nanostructures can be subcategorized in two

categories, bioactive nanostructures and physico-chemical active nanostructures.

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Integrated nanosystems



These systems would be the future of nanotechnology. They would include

assembling techniques like bio-assembling, networking at the nanoscale, modular

nanosystems, etc. The example of these systems would include development of a

system for medical purposes that could be able to build organs from nanoscale.

In electronics one could see new devices based on states other than electric

charge.

Atomic force microscope image of carbon nanotubes. Apart

from their favorable mechanical and electrical properties these nanotubes

also have disadvantageous characteristics.

Heterogenous molecular nanosystems



These systems would consist of molecules, with each one having a different

purpose. This would give the nanosystem to ability to work in a similar manner

as our biological system works but these man made systems would be more energy

efficient, and quick in action. These nanosystems would have the ability to self

assemble at different levels giving them the ability to self heal. Nanorobots

would also have to be built to carry out actions at nano scale.

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Nanodevice applications



In nanoelectronics one can expect creation of self-assembly structures

allowing the scaling down of complementary metal-oxide semiconductors (CMOS) to

their ultimate limits (5-10 nm) and the possible post-CMOS (but still electron

charge-based) integrating nanocomponents and nanodevices such as carbon-nanotube

and single-electron transistors. Nanotechnology can further be of great help in

cutting down costs of sending spacecraft in outer space. This can be achieved by

building a structurally altered material that is lighter than traditional

material used, but at the same time is very strong to withstand a high pressure

environment.

Future of

Nanotechnology in health care
Bioavailability of the drug is defined as presence of drug

molecules in the affected area inside the body when these molecules can

provide maximum help. A 100% bioavailability of medicine can be achieved

using nanorobots. These hypothetical machines would be 0.5-3 micrometer in

size so that they can easily move around inside capillaries. The material

used to build these nanorobots would be carbon due to its strength and

favorable characteristics. The usage of special isotopes of carbon would

further help in tracking these robots using MRI scan. These devices would be

injected inside patient's body and then tracked for progress of work. Other

infesting tasks that can be done using nanotechnology is cell repair using

molecular devices. It is proved that molecules have ability to recognize,

repair and destroy other molecules. It is also possible to insert molecules

inside cell using needles without damaging them. Now if molecular machines

are built and injected in cells they would be able to effectively repair

cells even those that are dead. After repairing all cells in tissue one can

repair a complete tissue. Further, molecular machines can be made

intelligent i.e. instead of doing a specialized work these devices can have

artificial intelligence for doing tasks.

Risks involved



Altering material structure could result in negative effects on environment

and potential health hazards. Therefore it is advisable to follow a defined

framework in developing these materials. Due to the high surface-area-to-volume

ratio and higher reactivity of nanostructures, large doses can cause cells and

organs to demonstrate a toxic response even when the material itself is

non-toxic.

Nano materials could combine with other materials and this cocktail could be

toxic in nature. Further due to higher surface reactivity of nanopowders there

is increased risk of explosion or ignition. One more negative effect could be

accumulation of nonmaterials in environment or human organs with potential

negative effects.

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