SOLAR CLUB CERN
AUTRES FUTURS DU SOLAIRE:
Tiny Body-POWERED Battery Could Run Medical Implants
!
New York Times Syndicate
Bob Keefe 09/23/2002
Deep in his basement laboratory at the University
of California, Berkeley professor Liwei Lin holds what may become one of
the most innovative medical devices in recent years.
It certainly doesn't look impressive. Little more
than a tiny semiconductor chip with tubes and tinfoil dangling off it,
the device resembles a mechanical bug or something fashioned by a bored
kid from leftover electronics parts.
But this gadget does something extraordinary. It
produces energy from bodily fluids.
Lin's device is fueled by glucose, a sugary substance
that's typically abundant in human blood. When glucose is combined with
a naturally occurring microorganism, Saccharomyces cerevisiae - commonly
known as baker's yeast - it generates electricity that Lin's fuel cell
can harness and distribute.
Think about Doc Brown's car in ``Back to the Future.''
Only instead of using dinner leftovers for fuel, Lin's device uses leftover
glucose.
Lin's little fuel cell isn't nearly powerful enough
to power a car or anything remotely that big. But in lab experiments, the
device has churned out 300 microvolts for two hours - enough, Lin claims,
to power devices such as next-generation heart pacemakers or tiny implantable
pumps that can deliver pain drugs for cancer patients or insulin for diabetics.
The device still faces plenty of hurdles, including
federal approval, before it might come to the marketplace. And Lin admits
there's still plenty of work to be done.
``In labs you can put things together, test them
and make sure everything works OK,'' he said. ``But in the human body,
that's different.''
Nonetheless, the device is already attracting some
interest from pharmaceutical companies, including drug delivery company
Alza Corp., which last year was acquired by Johnson & Johnson Inc.
``We are mechanical engineers,'' Lin said of himself
and several graduate students who developed the fuel cell. ``We don't know
biology. But from what we understand, people have been looking for something
like this for a long time.''
Diagnosing medical problems and delivering drugs
from inside the body has been a dream of doctors since before Isaac Asimov's
1966 science fiction classic ``Fantastic Voyage,'' in which a group of
doctors are miniaturized and injected into a patient to remove a blood
clot.
Doctors can't be shrunk, but drug delivery systems
have continually evolved - from shots to pills to respiratory inhalers
to patches applied to the skin. With recent biotech and genomics advances,
implantable drug delivery systems that can automatically administer individualized
doses of medication are starting to move from science fiction to reality.
In recent years, drug makers have introduced at
least a half-dozen devices that can be implanted under the skin to automatically
administer hormones and drugs to a patient. More are on the way.
``This is an area that's been growing exponentially,''
said Dr. Diane Burgess, president of the American Association of Pharmaceutical
Scientists. Burgess specializes in drug delivery systems research at the
University of Connecticut.
``And as we go more and more into individualized
medicine as a consequence of (human genome research), we're going to be
utilizing more and more internal delivery systems,'' she said.
Along with eliminating shots and pills, there are
other benefits to drug dispensers implanted inside the body. Pain relievers
can work more quickly and effectively. Drug ``cocktails,'' such as those
used by some AIDS patients, can be administered more easily. And internal
devices can take measurements of body conditions and adjust dosage levels
automatically.
One of the many problems with internal drug delivery
systems, however, is power. Right now, batteries work for things like pacemakers,
but as devices get even smaller and more complex, supplying them with juice
becomes more complicated.
That's where Lin's technology comes in.
While the glucose and yeast provide a sustainable,
self-sufficient fuel supply, its only by-products are carbon dioxide and
water, which the body naturally filters out.
``To think that people could potentially have a
drug infusion system that was powered by their own blood sugar, ... that
would be a very important advance,'' said Dr. Paul Kefalides, a New York
gastroenterologist who has written about internal medicine delivery systems.
``It sounds like an innovation that could open up some new frontiers and
new opportunities.''
Like so many new advances, medical and otherwise,
Lin's discovery of the fuel cell was unintentional.
He and his graduate students stumbled upon it while
working on a two-year, $2.5 million defense grant to develop a wristwatch-sized
sensor that can be used by soldiers to detect biological weapons such as
nerve gas.
That device is still in development - though the
researchers now have a fuel source for it.
