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Coating improves electrical stimulation therapy used
for Parkinson's, depression, chronic pain
Other Topics:
Carbon Nanotube Interconnects,
DNA
Nanotechnology Test
Eureka Alert
September 16, 2008
DALLAS – Researchers at UT Southwestern Medical Center have
designed a way to improve electrical stimulation of nerves
by outfitting electrodes with the latest in chemically
engineered fashion: a coating of basic black, formed from
carbon nanotubes.
The nanotube sheathing improves the signals received and
transmitted by electrodes, which researchers say is a
potentially critical step for advancing electrical nerve
stimulation therapy. This type of therapy increasingly shows
promise for diseases ranging from epilepsy to depression to
chronic leg and back pain. |
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By implanting electronic nerve stimulators, doctors
elsewhere have provided a quadriplegic patient with the
ability to move a computer cursor at will, and monkeys have
been able to move objects in a virtual world with mere mind
power. For individuals who lose an arm or leg and rely on
prosthetics, implanted stimulators offer promise in
restoring feelings of sensation.
"The key to success for these types of brain-machine
interfaces is where the electrode meets the nerve tissue,"
said Dr. Edward Keefer, instructor of plastic surgery at UT
Southwestern and lead author of the study appearing in a
recent issue of Nature Nanotechnology. "When we coat the
electrodes with carbon nanotubes, it improves the
stimulation of the nerve and the feedback from the sensors."
Depending on the way the nanotubes are fashioned,
researchers were able to bolster either the stimulation or
receptive capabilities to improve performance. In some
tests, the nanotube coating improved performance by
fortyfold, while in others it improved by a factor of as
much as 1,600.
Nanotubes look
like lattices rolled into a tube on a microscopic scale.
Although they are 1/50,000 the width of a human hair,
nanotubes are nonetheless among the stiffest and strongest
fibers known, as well as excellent conductors of
electricity.
Those properties proved to be just the attributes needed to
help electrophysiologists conquer some of the hurdles facing
them – issues such as battery power and chemical stability.
The carbon nanotube coating improves conductivity, which
means less energy is needed to power the nerve stimulator.
That can help reduce routine maintenance, such as the need
to change batteries in implanted stimulation devices, as
well as reduce tissue damage caused by the electrical
charge.
"Our process is like taking a Ford Pinto, pouring on this
chemical coating, and turning it into a Ferrari," Dr. Keefer
said.
Researchers have tried several types of electrochemical
coatings to see if they could improve conductivity, but the
coatings often break down quickly or fail to stay affixed to
the electrodes. The carbon nanotube coating shows far more
promise, although further research is still needed, Dr.
Keefer said.
"The development of new technologies by Dr. Keefer to
potentially restore function in wounded tissues and future
transplantations is exciting," said Dr. Spencer Brown,
assistant professor of plastic surgery who heads research in
the Nancy Lee and Perry R. Bass Advanced Plastic Surgery and
Wound Healing Laboratory at UT Southwestern. |
