New 'nano-positioners' may have atomic-scale...( WEST LAFAYETTE Ind. - Engineers have...)

WEST LAFAYETTE, Ind. - Engineers have created a tiny motorized positioning device that has twice the dexterity of similar devices being developed for applications that include biological sensors and more compact, powerful computer hard drives.

The device, called a monolithic comb drive, might be used as a "nanoscale manipulator" that precisely moves or senses movement and forces. The devices also can be used in watery environments for probing biological molecules, said Jason Vaughn Clark, an assistant professor of electrical and computer engineering and mechanical engineering, who created the design.

The monolithic comb drives could make it possible to improve a class of probe-based sensors that detect viruses and biological molecules. The sensors detect objects using two different components: A probe is moved while at the same time the platform holding the specimen is positioned. The new technology would replace both components with a single one - the monolithic comb drive.

The innovation could allow sensors to work faster and at higher resolution and would be small enough to fit on a microchip. The higher resolution might be used to design future computer hard drives capable of high-density data storage and retrieval. Another possible use might be to fabricate or assemble miniature micro and nanoscale machines.

Research findings were detailed in a technical paper presented in July during the University Government Industry Micro/Nano Symposium in Louisville. The work is based at the Birck Nanotechnology Center at Purdue's Discovery Park.

Conventional comb drives have a pair of comblike sections with "interdigitated fingers," meaning they mesh together. These meshing fingers are drawn toward each other when a voltage is applied. The applied voltage causes the fingers on one comb to become positively charged and the fingers on the other comb to become negatively charge
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