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Cross Posted

This news tidbit highlights the very innovative use of nanotechnology in

helping researchers to screen compounds as drug candidates.

Good reading!

Cheryl-Anne

Nanowires track molecular activity

As molecules go, DNA and viruses are relatively large. Many prototype

sensors are aimed at detecting large biological molecules, but small organic

molecules also play important roles in biological systems, and most

pharmaceutical drugs are small molecules.

Researchers from Harvard University have found a way to use transistors made

from silicon nanowires to gain information about how small molecules bind to

proteins. The nanowires are 20 nanometers in diameter, and the electrical

conductance of the devices changes measurably depending on whether target

molecules bind to receptor molecules attached to the nanowires. A nanometer

is one millionth of a millimeter, or the span of 10 hydrogen atoms.

The nanowire transistors could eventually be used in sensor arrays capable

of simultaneously detecting many different molecules, including small

organic molecules. The method is potentially capable of rapidly screening

drug candidates, according to the researchers.

The researchers' prototype consists of arrays of several dozen sensors that

sense when adenosine triphosphate (ATP) molecules bind to the receptor

molecules on the nanowires. The researchers showed that the device could

measure how effectively the small molecule drug Gleevec blocked the

ATP-receptor binding.

The receptor molecule Abl binding with ATP is part of a cell signaling

process that, when altered, plays a role in many diseases. Gleevec is used

to treat chronic myelogenous leukemia.

The researchers also showed that it is possible to measure the degree to

which four other small molecules blocked the ATP binding.

The sensors could be ready for practical use in two to five years, according

to the researchers.

The work appeared in the February 14, 2005 issue of the Proceedings of the

National Academy Of Sciences.