Machines As Small As Viruses 

Nanotechnology to usher in a 
technological revolution, says Biplab Das 

Is it possible to cram the 24 volumes of the Encyclopaedia Britannica on the head of a pin? Theoretically speaking, it is feasible. In 1959, physicist Richard Feynman said that it would be possible by manipulating matters at the atomic scale. Though scientists are yet to write the miniscule version of the Britannica, they have mastered the art of plodding atoms, and an entire area of activity called nanotechnology has come into being. 

"The technological innovations triggered by the invention of transistors is now on the brink of another revolution to be ushered in by nanotechnology," said Dr. H. S. Maiti, director, Central Glass and Ceramic Research Institute. "The advent of nanotechnology has literally fuelled the mad rush to miniaturise machines." Maiti was delivering a lecture on 'Nanomaterials: The Next Basis of Technological Revolution' at a recently-held seminar on 'Nanotechnology: Present Status and Future Prospects.' The seminar was organised by the chemical technology department of the Calcutta University as a part of the department's reunion. 

Sophisticated imaging techniques show that atoms and molecules coalesce to form clusters of nanoparticles, which eventually give rise to stable nanomaterials, Maiti said. "Most of the nanomaterials cluster on the surface area of the matter." Nanomaterials exhibit wonderful properties, having a wide range of potential applications. 

"Nano-size particles of cadmium sulphide have already shown promising results in medical diagnostics. Nanoparticles of titanium dioxide can be used in solar cells to harness solar energy," Maiti said. 

According to him, scientists have already made carbon nanotubes rolling up sheets of graphite. Such nano-size graphite materials will herald a new era in the chips. 

Another amazing nanomaterial is fumed silica. "It is produced when crystals of silicon dioxide are heated at 1,800°C and passed through chlorine gas and flames of hydrogen and oxygen," said Dr. Jan Olaf Roziniski of the Elkem Materials, Norway. "Nano-size fumed silica fills in the voids of building materials, increasing the strength of cement." 

Nanoparticles are also widely used in targeted drug delivery. "Using them in drug delivery can eliminate excessive dosage and increase the availability of a particular drug," said Dr. Mamata Mukhopadhyay of the Indian Institute of Technology, Mumbai. "Using what is called supercritical carbon dioxide technology, we have produced nano-size materials like powdered inhalers."