March 11, 2008

Duroquinone: A Parallelly Processing Chemical Computer

Duroquinone nanobots constituting chemical brainDr Anirban Bandyopadhyay of the National Institute for Materials Science, Tsukuba, Japan, have developed a tiny chemical nano-brain, that could one day be guided by remote control. These machines could make surgery on human bodies easier and help revolutionize the computing power of future computers.

Scientists have built nanobots (nanoscale robots; nano means a billionth of a metre) previously but these bots could not be controlled by outside means. Dr. Bandyopadhyay has now devised a nanobot, a chemical one and not mechanical or electronic one, that can be controlled from outside.

This promising nanomachine, just 2 billionths of a meter across, consists of a molecule called duroquinone. A single nanomachine comprises of 17 duroquinone molecules; with one molecule at the center and remaining 16 surrounding it. All these molecules are connected by hydrogen bonding. As is shown in the figure, each duroquinone molecule has four spoke like arms jutting out from it, which can be independently rotated to represent four different states. Thus they can be made to represent four different 'logic states', bits: 0,1,2,3. While ordinary computers work on binary logic (0,1), computers using this technology would have four billion possible combinations with this chemical brain.

The molecule at the center, to which the rest are connected, can be controlled by a scanning tunneling microscope (STM). This machine is not only capable of 'manipulating/directing' their (nanobots') orientations, it is also capable of 'reading' the states they are in. They act rather like both a transducer and a receiver. By tweaking the central molecule, one could switch the nanobot's configurations. Comparable switches in electronic circuits include CD4066, a quad bilateral switch, electrical relays, transistors and others. But here, we are controlling a chemical device by using STMs. In future, we may be able to operate the duroquinone machinery by using the conformational properties of proteins, by optical devices like lasers and may be other electromagnetic devices too.

The researchers were inspired by the parallel processing circuitry of the glial cells in the brain.
Said Dr. Bandyopadhayay, "Doctors will inject molecular machines attached to similar control unit, the assembly will go to the target part inside our body through veins, and carry out bloodless surgery. Till now several molecular machines have been built, prior to this work, but there were no machine that could control them."

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