18-05-2012, 01:09 PM
NANOTECHNOLOGY
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"Science and technology alone are not going to magically solve all the problems of developing countries but they are critical components of development. Nanotechnology is a relatively new field that will soon be providing radical and relatively inexpensive solutions to critical development problems." Thus, scientists are harnessing nanotechnology to create new, inexpensive materials, devices, and systems with unique properties. Most of current applications of nanotechnology are in electronics, automation, supermaterials, agriculture, food security systems or life sciences such as pharmaceuticals and medicine.
Nanotechnology is the study, design, creation, synthesis, manipulation, and application of functional materials, devices, and systems through control of matter at the nanometer scale (one nanometer being equal to 1 x 10-9 of a meter), and the exploitation of novel phenomena and properties of matter at that scale.
Nanotechnology is more properly labeled as "molecular nanotechnology (MNT), or "nanoscale engineering Recently, the Foresight Institute has suggested an alternate term to represent the original meaning of nanotechnology: zettatechnology..
NANOTECHNOLOGY SEGMENTS
One way of characterizing nanotechnology is by "tools", "materials", "devices" and "intelligent materials and machines".
Tools
Nanotechnology tools include microscopy techniques and equipment that permit visualization and manipulation of items at the nanoscale such as cells, bacteria, and viruses, and to detect single molecules to better understand the nature of science. The range of tools includes the atomic force microscope (AFM), scanning tunneling microscope (STM), molecular modeling software and various production technologies.
Materials
Nanomaterials can be grouped into three main areas:
1. Raw nanomaterials
2. Nanostructured materials
3. Nanotubes
Devices
two classes of miniature devices are commonly associated with nanotechnology:-
Nano devices
Mirodevices
CONSTRUCTION
Two approaches can be taken when making something at the nanoscale: these are known as the 'top-down' approach and the 'bottom-up' approach.
Top-down approach
1. The top-down approach is analogous to making a stone statue. You take a bulk piece of material and modify it, by carving or cutting in the case of stone, until you have made the shape you want. The process involves material wastage and is limited by the resolution of the tools you can use, restricting the smallest sizes of the structures made by these techniques. Examples of this kind of approach include the various types of lithographic techniques (such as photo-, ion beam-, electron- or X-ray-lithography) cutting, etching and grinding.
Bottom-up
The second approach is known as the bottom-up approach. This can be thought of as the same approach one would take to build a house: one takes lots of building blocks and puts them together to produce the final bigger structure. There is less wastage with this technique, and strong covalent bonds will hold the constituent parts together.
A good example of this kind of approach is found in nature; all cells use enzymes to produce DNA by taking the component molecules and binding them together to make the final structure. Chemical synthesis, self-assembly, and molecular fabrication are all examples of bottom-up techniques.
Nanofilms
Different nanoscale materials can be used in thin films to make them water-repellent, anti-reflective, self-cleaning, ultraviolet or infrared-resistant, antifog, anti-microbial, scratch-resistant, or electrically -conductive. Nanofilms are used now on eyeglasses, computer displays, and cameras to protect or treat the surfaces.
Nanotubes
Carbon nanotubes (CNTs) are used in baseball bats, tennis racquets, and some car parts because of their greater mechanical strength at less weight per unit volume than that of conventional materials. Electronic properties of CNTs have made them a candidate for flat panel displays in TVs, batteries, and other electronics. Nanotubes for various uses can be made of materials other than carbon.
Drug-Delivery Techniques
Dendrimers are a type of nanostructure that can be precisely designed and manufactured for a wide variety of applications, including treatment of cancer and other diseases. Dendrimers carrying different materials on their branches can do several things at one time, such as recognizing diseased cells, diagnosing disease states (including cell death), drug delivery, reporting location, and reporting outcomes of therapy.
Nanoscale transistors
Transistors are electronic switching devices where a small amount of electricity is used like a gate to control the flow of larger amounts of electricity. In computers, the more transistors, the greater the power. Transistor sizes have been decreasing, so computers have become more powerful. Until recently, the industry's best commercial technology produced computer chips with transistors having 65-nanometer features. Recent announcements indicate that 45-nanometer feature technology soon will be here.
The top 10 nanotechnology applications are:
1. Energy storage, production and conversion;
2. Agricultural productivity enhancement;
3. Water treatment and remediation;
4. Disease diagnosis and screening;
5. Drug delivery systems;
6. Food processing and storage;
7. Air pollution and remediation;
8. Construction;
9. Health
10 Monitoring;
11. Vector and pest detection and control.
NANOMEDICINE: THE MEDICAL REVOLUTION
Technically nanomedicine is the application of nanotechnology for engineering of tiny machines for the prevention and treatment of disease in human body. Nanomedicine devices will be used in
-diagnosis of illness,
-implanted devices to deliver drugs or hormones
-use miniature surgeons
-tissue repair and replacement