New on-off 'switch' triggers, reverses paralysis in animals with light beam

Washington, Feb 4 (ANI): Canada scientists have developed an internal on/off switch that has been found to paralyse animals when exposed to a beam of ultraviolet light.

The animals stay paralyzed even when the light is turned off. However, when they were exposed to ordinary light, the animals become unparalyzed and wake up.

Researchers say that such photoswitches may have great potential in turning photodynamic therapy on and off, and for other applications in medicine and research.

According to lead researcher Neil Branda, "photoswitches" - light-sensitive materials that undergo photoreactions - have been available for years.

Doctors use light-sensitive materials and photoreactions in medicine in photodynamic therapy to treat certain forms of cancer.

The researchers believe that such a light-activated switch in animals might have therapeutic options.

The research team tested a photoswitch composed of the light-sensitive material, dithienylethene.

They grew transparent, pinhead-sized worms (C. elegans) and fed them a dithienylethene. When exposed to ultraviolet light, the worms turned blue and became paralyzed. When exposed to visible light, the dithienylethene became colorless again and the worms' paralysis ended.

The study appears in the Journal of the American Chemical Society (JACS).