A small, unmanned vehicle makes its way down the road ahead
of a military convoy. Suddenly it stops and relays a warning to the
convoy commander. The presence of a deadly improvised explosive device,
or IED, has been detected by sophisticated new sensor technology
incorporating living olfactory cells on microchips mounted on the
unmanned vehicle. The IED is safely dismantled and lives are saved.
This scenario may become a reality, thanks to the work of
three faculty researchers in the University of Maryland's A.
James Clark School of Engineering who are collaborating
across engineering disciplines to make advanced "cell-based
sensors-on-a-chip" technology possible. Pamela Abshire, electrical and
computer engineering (ECE) and Institute for Systems Research (ISR);
Benjamin Shapiro, aerospace engineering and ISR; and Elisabeth Smela,
mechanical engineering and ECE; are working on new sensors that take
advantage of the sensory capabilities of biological cells.
These tiny sensors, only a few millimeters in size, could
speed up and improve the detection of everything from explosive
materials to biological pathogens to spoiled food or impure water.
Today's biochemical detectors are slow and produce an
unacceptable number of false readings.
They are easily fooled because they often cannot distinguish
subtle differences between deadly pathogens and harmless substances,
and cannot fully monitor or interpret the different ways these
substances interact with biological systems. To solve this problem, the
Clark School researchers are learning how to incorporate real cells
into tiny micro-systems to detect chemical and biological pathogens.
Different cells can be grown on these microchips, depending on
the task at hand. Like a bloodhound hot on the trail of a scent, a chip
containing a collection of olfactory cells plus sensing circuits that
can interpret their behavior could detect the presence of explosives.
The researchers plan to use other specialized cells much like
a canary in a coal mine. The cells would show stress or die when
exposed to certain pathogens, and the sensing circuits monitoring them
would trigger a warning -- more quickly and accurately than in present
The researchers are tackling the many challenges that must be
met for such chips to become a reality. Abshire, for example, is
building circuits that can interact with the cells and transmit alerts
about their condition. Shapiro and Smela are working on micro-fluidics
technology to get the cells where they need to be on the chip, and to
keep them alive and healthy once they're in position. Smela is also
developing packages that incorporate the kind of wet, life-sustaining
environments the biological components need, while keeping the
sensitive electronic parts of the sensor dry.
Current research funding for the cell-based sensor technology
comes from the National Science Foundation, the Department of Homeland
Security and the Defense Intelligence Agency. Potential applications
for their use extend well beyond national security, however.
For example, cell-based sensors could detect the presence of
harmful bacteria in ground beef or spinach, or detect the local origin
of specialty foods like cheeses or wines. In the pharmaceutical
industry they could identify the most promising medicines in advance of
animal and human trials, increasing cost-effectiveness and speed in
developing new drugs. And they could speed up research in basic
science. Imagine tiny biology labs, each one on a chip, in an array of
thousands of chips that could fit in the palm of your hand.
Such arrays could advance biologists' fundamental
understanding about the sense of smell or help doctors better see how
the immune system works. They could be placed on fish as they swim in
the ocean to monitor water quality, or set on a skyscraper's roof to
evaluate air pollution.
"We bring the capability to monitor many different cells in
parallel on these chips," explains Abshire. "You could say we're
applying Moore's Law of exponentially increasing computer processing
capability to cell biology."
The research won the University of Maryland's 2004 Invention
of the Year Award in the physical science category. A patent
application is on file with the U.S. Patent and Trademark Office.