Light Powers Nanobrake

A tiny light-powered "molecular brake" that works at room temperature has been developed by researchers in Taiwan and could be used to stop future nanomachines on demand.

Jye-Shane Yang, PhD, a professor at National Taiwan University, and his colleagues at the university and the Institute of Chemistry, Academia Sinica in Taipei, assembled the prototype molecular brake.

Thousands of times smaller than the width of a human hair, the brake resembles a tiny four-bladed wheel and contains light-sensitive molecules. The paddle-like structure spins freely when a nanomachine is in motion. In laboratory studies, the scientists showed that exposing the structure to light changes its shape so that "blades" stop spinning, putting on the brakes. The braking power can be turned off by altering the wavelength of light exposure.

They used photons because they are cleaner, faster and longer-range control elements compared to chemicals and electrons, the researchers said in their study.

The ability to control specific motions of small molecules or larger molecular structures is essential for the development of nanomachines, which may one day be used to deliver drugs or perform surgery deep inside the body, the scientists said. Although molecular motors, wheels, and gears for powering nanomachines have already been built, the development of a practical braking system remains a challenge, they said.

Yang's group is now working with the nanobrake in the lab to see how using different types of molecules affects its performance.

Their study, "A Pentiptycene-Derived Light-Driven Molecular Brake," is scheduled to appear in the June 5 issue of the American Chemical Society's biweekly journal Organic Letters.

For more information, visit: http://pubs.acs.org