November 18, 2009
On-Off ‘Switch’ Triggers, Reverses Paralysis In Animals With Beam Of Light
In an advance with overtones of Star Trek phasers and other sci-fi ray guns, scientists in Canada are reporting development of an internal on-off "switch" that paralyzes animals when exposed to a beam of ultraviolet light. The animals stay paralyzed even when the light is turned off. When exposed to ordinary light, the animals become unparalyzed and wake up. Their study appears in the Journal of the American Chemical Society (JACS). It reports the first demonstration of such a light-activated switch in animals.
Neil Branda and colleagues point out that such "photoswitches" -- light-sensitive materials that undergo photoreactions -- have been available for years. Scientists use them in research. Doctors use light-sensitive materials and photoreactions in medicine in photodynamic therapy to treat certain forms of cancer. Those light-sensitive materials, however, do not have the reversibility that exists in photoswitching.
Image Caption: This tiny worm became temporarily paralyzed when scientists fed it a light-sensitive material, or "photoswitch," and then exposed it to ultraviolet light. Credit: American Chemical Society
On the Net:
- American Chemical Society
- Article: A Photocontrolled Molecular Switch Regulates Paralysis in a Living Organism