Opposites, many lovers say, can and do attract-it's just a matter
of the right chemistry. A team of University chemists believes
this maxim can be true at the cellular level too, and its research
is bringing together the most extreme of opposites-living cells
and man-made materials-in an effort to create tiny biomedical
devices smart enough to communicate with the body's building blocks.
technologies underlying microelectronics and biotechnology are
completely different," says Milan Mrksich, associate professor
in chemistry, who presented his team's work on surface chemistry
in September at the BioMEMS and Biomedical Nanotechnology World
conference. "That means it's difficult to combine these two technologies
into some common application or technology."
and his group have two goals: not only are they figuring out how
to join cells with manufactured materials, they're also teaching
the two to talk to each other, by converting electrical signals
into biological ones and vice versa, translating the activity
of specific cells into a language that a microprocessor can understand.
The "surface" aspect of the research is important because that's
where two critical functions occur: cell adhesion (getting cells
and manufactured materials to stick together) and cell migration
(how cells move). Mrksich's team is designing electrically active
surfaces that enable the scientists to control both functions
in an experimentally clean, systematic way.
applications include biomedical instruments for pharmaceutical
research and medical diagnostics; inexpensive, portable devices
that can monitor anything from blood chemistries to bacteria in
ground beef; new prosthetics; and sophisticated sensors able to
detect infection from biological warfare. Mrksich is especially
intrigued by the potential for new drugs to affect cell migration.
"In cancer, cell migration is a key element that leads to the
spread of a tumor," he says. "A lot of anticancer drugs function
by blocking migration of tumor cells. It's important for the pharmaceutical
companies to have tests that evaluate molecules for their ability
to block cell migration."
addition to blocking movement, the researchers hope to learn other
ways to control cell activity. For example, they are developing
cell-based sensors and learning how to integrate cells with electronics
so the cell itself serves as a sensor. The goal is to design a
device that will electrically signal when a cell becomes infected
with a hazardous agent like anthrax or smallpox. Such early-warning
sensors could detect exposure days before victims show symptoms.
"It's difficult to make man-made sensors that can detect those
agents at low levels quickly and reliably," Mrksich explains.
"At the same time, cells are good at detecting these agents because
they are the natural victims of those agents."
companies already use cells as sensors in drug development. "By
building devices that can more rapidly and accurately tell us
how the cells respond to potential drugs," says Mrksich, "we can
know if the drugs are toxic before we go to clinical trials, and
we can better understand what side effects they might have before
we test them in people."
work also could be useful in the development of prosthetic devices
for people who have lost muscular control because of nerve or
spinal cord damage. It would be possible, in theory, to engineer
an implantable device that re-establishes connections with neurons,
allowing the brain to again link to and control a muscle. The
challenge, Mrksich says, is to learn how to connect an electronics
component with neurons so the component recognizes when a neuron
fires, then relays that signal, causing another neuron or a muscle