Know about Nanotechnology – Customization of molecules and atoms

WEBNESBAY — Fri, 08 Jan 2010 05:12:45 +0000

Everything is made up of molecules which in turn are made up of atoms, now customization at these levels to get a useful product is what nanotechnology is helping us achieve

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.

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.

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.

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.

Source: PCQUEST

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Know about Nanotechnology – Customization of molecules and atoms