Artificial muscles `restore ability to blink`

Updated: Jan 18, 2010, 00:00 AM IST

Washington: In a major breakthrough that
may benefit thousands of people who can`t close their eyelids,
scientists have showed that artificial muscles can restore the
ability of facial paralysis patients to blink.

A team at California University has also demonstrated
that the technique, that uses a combination of electrode leads
and silicon polymers, can be used to develop synthetic muscles
to control other parts of the body, the `Archives of Facial
Plastic Surgery` reported.

"This is the first-wave use of artificial muscle in
any biological system. But there are many ideas and concepts
where this technology may play a role," said Travis Tollefson,
who led the team.

In fact, in their research, the scientists were
seeking to develop the protocol and device design for human
implantation of electroactive polymer artificial muscle (EPAM)
to reproducibly create a long-lasting eyelid blink that will
protect the eye and improve facial appearance.

EPAM is an emerging technology that has the potential
for use in rehabilitating facial movement in patients. They
act like human muscles by expanding and contracting, based on
variable voltage input levels.

"Reanimating faces is a natural first step in
developing synthetic muscles to control other parts of the
body. Facial muscles require relatively low forces, much less
than required to move the fingers or flex an arm," said team
member Craig Senders.

For their study, the scientists used a novel method
for eyelid rehabilitation in permanent facial paralysis. They
used an eyelid sling mechanism to create an eyelid blink when
actuated by an artificial muscle.

Using cadavers, the surgeons inserted a sling made
of muscle fascia or implantable fabric around the eye. Small
titanium screws secured the eyelid sling to the small bones of
the eye.

The sling was attached to a battery-operated
artificial muscle. The artificial muscle device and battery
were into a natural hollow at temple to disguise its presence.

The team found that the force and stroke required
to close the eyelid with the sling were within the attainable
range of the artificial muscle.

This capability may allow the creation of a realistic
and functional eyelid blink that is symmetric and synchronous
with the normal, functioning blink. A similar system also
could give children born with facial paralysis a smile, the
scientists said.

"The amount of force and movement the artificial
muscle generates is very similar to natural muscle," Tollefson
said, adding the technology will be available for patients
within the next five years.