By Jim Davis
WVU scientists have manipulated chemical
waves in experiments that may one day lead to controlling abnormal
electrical waves in the heart or brain to ward off a heart attack
or epileptic seizure.
The researchers, led by chemistry Professor Ken Showalter, reported
in the cover story of the June 14 issue of Science that
they have controlled the movements of photosensitive chemical
waves with light from a computer-controlled video projector.
"We've learned
we can control the motion of these waves through methods of control
theory," said Showalter, who co-authored the article with
post-doctoral associates Eugene Mihaliuk and Tatsunari Sakurai,
and physics graduate student Florin Chirila.
The article, "Design and Control of Patterns of Wave Propagation
in Excitable Media," is also available on the Science
web site at www.sciencexpress.org. Science is a journal
of the American Association for the Advancement of Science.
The experiments in Showalter's chemistry lab involved monitoring
and controlling chemical waves on a photosensitive Belousov-Zhabotinsky
medium, a widely used chemical reaction for studying wave behavior.
The researchers captured images of the waves with a video camera,
then altered the direction the waves travel with light from the
video projector in real time. They were able to produce various
wave patterns using this method, from a simple circular pattern
to complex shapes resembling roads on a map.
Although the team's work is basic research, Showalter is optimistic
the findings could one day be of use in the medical field.
"There are what we call propagating waves throughout all
living systems," he said. "These biological wave systems
are difficult to study, so we study chemical model systems instead.
What we learn from simple chemical systems we can then apply
to understanding more complicated biological systems."
One such complicated biological wave system is in the heart,
Showalter said. A disruption in the heart wave motion causes
the formation of spiral waves. Medical researchers believe spiral
waves lead to tachycardia, or rapid heart beat, often a precursor
to a heart attack.
Waves also travel through brain tissue, he added. Electrical
wave behavior on the surface of the brain is complex and without
apparent order. In people with epilepsy, a region of the brain
sends out waves in a rhythmic pattern that leads to a seizure.
Showalter said the researchers' work holds particular promise
for people with heart disease or epilepsy. For example, medical
researchers might develop miniature computers that, when implanted
in the chest or brain, could deliver a small shock at the sign
of any irregular wave activity, preventing the onset of a heart
attack or seizure.
Showalter, whose work is supported by the National Science Foundation
and others, has been studying propagating chemical waves for
several years and has written numerous scientific papers on his
research. This is the third article he has authored for Science.