New battery technology helps stimulate nerves

[Guest guest]

New battery technology helps stimulate nerves

http://www.medicalnewstoday.com/medicalnews.php?newsid=31557

05 Oct 2005

With the help of new silicon-based compounds, scientists -- and

patients -- are getting a significant new charge out of the tiny

lithium batteries used in implantable devices to help treat nervous

system and other disorders.

The lithium battery is the workhorse in implantable devices --

stimulators used to jump start the heart and help the central nervous

system make critical connections in, for example, Parkinson's and

epilepsy patients. Designed to be extraordinarily reliable and work

continuously for years, the tiny batteries that power implantables

are indispensable in everything from pacemakers to the electronic

stimulators that help restore function in the brains of Parkinson's

patients.

But lithium batteries don't last forever and new surgery to maintain

many devices seeded into the body is required, as it is to replace

batteries and devices at the end of their lives. Moreover, a new

generation of tiny electrical devices to stimulate the nervous

system, treat incontinence and overcome muscular impairment is coming

on line as scientists and engineers continue to shrink the components

that make up the devices.

Central to that ability, according to University of Wisconsin-Madison

Professor Emeritus of chemistry West, is new lithium battery

technology, technology capable of making batteries smaller, last

longer and, soon, accept a charge from outside the body without the

need for surgery.

Using organosilicon compounds, West and his UW-Madison colleagues

have developed a new generation of rechargeable lithium ion batteries

whose lifetimes are more than twice as long as the batteries now used

in the tiny medical devices.

" It turns out the organosilicon compounds are really good for

improving lithium battery technology, " says West, whose new battery

technology powers a " microstimulater " not much larger than a pencil

lead and that can be injected near target nerves to help overcome the

faulty nervous system wiring at the heart of Parkinson's, epilepsy

and incontinence.

" The idea is that whenever you have a broken nerve connection, you

can supply the electrical impulse to complete the circuit, " West

explains.

The microstimulator was developed by a consortium including UW-

Madison's Organosilicon Research Center, Argonne National Laboratory,

Advanced Bionics Corp., the Alfred Mann Foundation and Quallion, LLC.

The device was recognized earlier this year with an " R & D 100 Award "

from R & D Magazine.

West's group developed the electrolyte, the electricity-conducting

liquid that is the heart of the battery. The new organosilicon

compounds developed by the Wisconsin chemists, says West, have

numerous advantages over traditional lithium battery chemistry.

" They're very flexible. They don't solidify. They're stable,

nonflammable, non-toxic and they pose no threat to the environment, "

says West, an international authority on silicon chemistry. Silicon,

the stuff computer chips are made of, is one of the Earth's most

abundant elements. Organosilicons are compounds composed of silicon

and other natural materials.

In the context of the lithium battery, West's group has been making

and testing " designer silicons " that are specially formulated to

conduct electricity in a very compact environment. In the lithium

battery, charge is maintained as lithium ions flow between the

battery's positive and negative electrodes.

" The battery requires something the ions can go through easily. We

had to tweak the (organosilicon) molecules to get higher conductivity

and stability, " says West.

A critical advantage of the new battery technology is lifespan: " If

you're going to implant these things, you want a (battery) lifetime

of at least 10 years, " says West, whose organosilicon batteries are

projected to power the tiny implantable devices for more than 12

years.

In addition to implantable devices for medicine, lithium batteries

are used in scores of applications, from spacecraft to iPods.

Patented through the Wisconsin Alumni Research Foundation, the new

organosilicon compound technology is also being developed through a

new start-up company, Polyron, Inc. The work to develop the new

organosilicon compounds was funded by the National Institute of

Standards and Technology, a federal technology agency that works with

industry to develop and apply technology, measurements and standards.

University of Wisconsin-Madison

wisc.edu