Nano- and Micro-Technology - Essay Example

The term nanotechnology was used by N. Taniguchi of the University of Tokyo in 1974, at micrometer scale (Slator, 2002). Well, it's been more than five decades since Richard Feynman talked about the Nano components around us and we are into 21st century. Though the use of nano-components has not come to our daily usage, but the way the scientific community is working hard, it appears quite realistic in times to come. The microscopic technological developments on the nanometer scale of 0.1 to 100 nm seems to be going ahead with decent pace.

Hocken et al. (2008) define nanotechnology as "the study, development and processing of materials, devices, and systems in which structure on a dimension of less than 100 nm is essential to obtain the required functional performance." Subsequent studies have indicated that when materials are reduced to nano-scale, they start exhibiting different types of properties, as compared to their performances in macro form. This proves that nano-structures can prove helpful in enabling unique applications.

The traditional top-down approach in micro-fabrication process implies that we break or cut bigger materials into smaller components. In this approach we fabricate nano-objects from a larger parent entity with the help of lithographic patterning techniques. The top-down approach uses the traditional workshop or micro-fabrication methods with externally-controlled tools1. Richard Feynman, while suggesting that 'there's plenty of room at the bottom', said, "We can arrange the atoms the way we want . . .

the very atom. . . all the way down!" At that time he could clearly visualise the top-down approach. The nano-fabrication technologies like photolithography, nanomolding, dip-pen lithography and nanofluidics are some examples of top-down approach. The top down approach has been used for fabricating tissue engineering scaffolds by controlling the pore geometry, size, distribution and spatial geometry2. On the other hand the bottom up approach indicates that we assemble smaller objects and build a larger useful entity.

This technique uses the molecular self assembly chemical process. In this case nanomaterials or structures are fabricated from the build-up of atoms or molecules in a controlled manner that is regulated by thermodynamic means such as self-assembly3. In order to come out with quality fabrication in the bottom up approach, shaping of the nano-object and extremely precise, nanometer-scale control in positioning the object is of vital importance (Berger, 2009). Whatever might be the approach in fabricating the nano-structures, it involves precise control and manipulation of atomic particles and molecules.

Fig-1 depicts the difference between top-down and bottom up approaches.Nanotechnology holds great potential in creating new materials and devices with applications in diverse fields like medicine, energy production, consumer electronics etc. In medicines it can be used in diagnostics, prevention as well as treatment. Some important