Tiny Microchips Have Big Promise In
Fighting Serious Diseases
Source: Ohio State University
September 27, 2000
COLUMBUS, Ohio - Treatment for life-threatening diseases
and relief from disease-related pain may one day be supplied by
microscopic chips that could be implanted in the body, according to
researchers in the new field of biomedical nanotechnology.
Such chips - called biological microelectromechanical
devices (bioMEMS) - are less than half the width of a human hair. They
could contain drugs, muscle cells or even be equipped to monitor a
patient's condition
minute-to-minute. And these devices already show therapeutic potential
for treating heart disease and diabetes.
"The development of these microscopic chips will let us
do a whole host of exciting things in biomedicine," said Robert
Michler, chief of cardiothoracic surgery at Ohio State University.
Michler and several colleagues discussed the role nanotechnology may
play in medicine of the future during a presentation Sept. 26 in
Columbus at the BioMEMS and Biomedical Nanotechnology World 2000
meeting, co-sponsored by Ohio State.
Michler said doctors in the future will combine the use
of nanotechnology with another revolutionary process - robotic
surgery. Michler led a study using robotic techniques to perform
open-heart surgery on 60 patients. Surgeons in the study took arteries
from the patients' chest walls and sewed them on to their hearts.
Robotic surgery has the advantage of precision, as it "can gain access
to very small areas inside the body," he said.
Michler envisions using robotic surgery to place
microchips inside the body, such as on heart tissue or blood vessels.
The chips could contain stem cells - cells that give rise to specific
types of cells, such as those comprising muscles, organs, blood and
other tissues. They could also
contain chemicals that would stimulate the growth of blood vessels, or
medication that is slowly released into the body, Michler said.
"The use of microscopic chips will take heart disease
treatment to the next level," he said. "It has the potential to let
physicians assess the benefit of their work right in the operating
room, rather than waiting to see if symptoms show up.
"We're ready to create the chips and use the robot to
insert them into the hearts of lab animals," Michler said. "We're
looking at probably five years before human clinical trials begin."
Joining Michler on the panel were Costantino Benedetti,
director of cancer pain, therapy and palliative medicine at the James
Cancer Hospital at Ohio State; Michael Caligiuri, the associate
director for clinical research at
Ohio State's Comprehensive Cancer Center; and Pascal Goldschmidt,
chief of cardiology at Duke University. They offered their perspective
on how nanotechnology will affect patient treatment in the future:
Treating the pain associated with surgery is poorly done
in more than 50 percent of patients, even with today's technology,
says Benedetti. Benedetti hopes for the development of a local
anesthetic that could last days - or
even weeks - and be released inside the body through slow-release
technology. Today's strongest local anesthetics last a maximum of
eight hours, Benedetti said. "A drug delivery system that would allow
a short-acting anesthetic to be released slowly would be
advantageous," he said. For example, a surgeon could place the
slow-release anesthetic in the wound at the end of the surgical
procedure, forgoing the need for traditional post-operation pain
relief. A painkiller released slowly inside the body would prevent the
pain impulses from reaching the brain, so a patient would never feel
the pain.
While the field of cancer vaccines is in its "infancy,"
said Caligiuri, there is the potential to develop a vaccine-containing
chip or slow-release capsule taken orally that can target specific
types of cancer. "Cancer prevention via vaccination is a huge
frontier," he said. Other than developing the appropriate vaccines,
obstacles to overcome also include
determining the right dose of the vaccine, where in the body to
deliver it and the duration of delivery. "Drug delivery devices would
give us much better control of dosing, thus enhancing the
effectiveness of the drug while limiting its toxicity," Caligiuri
said.
Also, a chip could house the tools to relay to
physicians information on potentially cancerous tissues. "Most men 70
and older harbor some evidence of pre-malignant or even malignant
cancer in the prostate tissue, although the majority of these will
never become a problem during their lifetime,"
Caligiuri said. But microchips equipped with sensors could detect
mutated genes or dangerous levels of hormones, and enable doctors to
determine which tissues to treat.
Microchips could contain stem cells - cells that give
rise to other specialized cells - that would grow and proliferate
inside the body. This chip technology could even create new tissue on
damaged organs. "Instead of transplanting a whole organ, we would do a
transplant using stem cells,"
Goldschmidt said. "These cells can be engineered inside the body to
ensure that normal heart tissue would form even in the region damaged
by a heart attack."
The possibilities also include cellular therapy -
Goldschmidt envisions one day using a device called a nanoneedle to
analyze the cells of heart tissue in a patient with heart disease.
Using such a small needle would allow doctors to "see" damaged genes.
They could then use stem cell transplantation to replenish the damaged
tissue. "It's a totally new way of detecting faulty genes,"
Goldschmidt said. "We could look at the
tissue in question and, without having to do a biopsy, see if the
tissue is damaged."
Goldschmidt also talked about "smart stents" - these
stents would support tissue and keep the blood vessels of the heart
open, and also be able to detect changes in blood flow. "Smart stents
would have a sensory role," Goldschmidt said. "They would gather
information on how blood flows through
the organ, without the need for a physician to directly examine the
blood vessels."
http://www.osu.edu/units/research/archive/nano.htm