New on-off 'switch' triggers and reverses paralysis in animals with a beam of light

Feb 03, 2010
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

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 . 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.

This video is not supported by your browser at this time.

The JACS report describes development and successful testing of a photoswitch composed of the light-sensitive material, dithienylethene. The scientists grew transparent, pinhead-sized (C. elegans) and fed them a dithienylethene. When exposed to , the worms turned blue and became paralyzed. When exposed to visible light, the dithienylethene became colorless again and the worms' ended. Many of the worms lived through the paralyze-unparalyze cycle. Scientists were not sure how the switch causes paralysis.

The study demonstrates that photoswitches may have great potential in turning photodynamic therapy on and off, and for other applications in medicine and research, they indicate.

Explore further: Jumping hurdles in the RNA world

More information: "A Photocontrolled Molecular Switch Regulates Paralysis in a Living Organism", Journal of the American Chemical Society.

add to favorites email to friend print save as pdf

Related Stories

Toward a nanomedicine for brain cancer

Sep 09, 2009

In an advance toward better treatments for the most serious form of brain cancer, scientists in Illinois are reporting development of the first nanoparticles that seek out and destroy brain cancer cells without ...

Glow worms glimmer on cue

Aug 18, 2008

(PhysOrg.com) -- University of Queensland researcher and lecturer Dr David Merritt has discovered Tasmanian cave glow-worms are energy conservationists: they switch their lights off at night-time.

Recommended for you

Jumping hurdles in the RNA world

Nov 21, 2014

Astrobiologists have shown that the formation of RNA from prebiotic reactions may not be as problematic as scientists once thought.

New computer model sets new precedent in drug discovery

Nov 18, 2014

A major challenge faced by the pharmaceutical industry has been how to rationally design and select protein molecules to create effective biologic drug therapies while reducing unintended side effects - a challenge that has ...

Finding new ways to make drugs

Nov 18, 2014

Chemists have developed a revolutionary new way to manufacture natural chemicals and used it to assemble a scarce anti-inflammatory drug with potential to treat cancer and malaria.

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.