Light Powers Nanobrake
TAIPEI, Taiwan, May 27, 2008 -- 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
- Electromagnetic radiation detectable by the eye, ranging in wavelength from about 400 to 750 nm. In photonic applications light can be considered to cover the nonvisible portion of the spectrum which includes the ultraviolet and the infrared.
- A quantum of electromagnetic energy of a single mode; i.e., a single wavelength, direction and polarization. As a unit of energy, each photon equals hn, h being Planck's constant and n, the frequency of the propagating electromagnetic wave. The momentum of the photon in the direction of propagation is hn/c, c being the speed of light.
- The technology of generating and harnessing light and other forms of radiant energy whose quantum unit is the photon. The science includes light emission, transmission, deflection, amplification and detection by optical components and instruments, lasers and other light sources, fiber optics, electro-optical instrumentation, related hardware and electronics, and sophisticated systems. The range of applications of photonics extends from energy generation to detection to communications and...
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