Blacksburg, VA (2/23/98) A new biosensor does its job
with far greater sensitivity and speed than anything currently in existence.
The sensor should prove useful in everything from detecting biological
agents such as anthrax, to pharmaceutical manufacturing and medical diagnostics.
the War in the Persian Gulf War in 1991, dozens of pathogens were not immediately
detected because the technology of the time was not up to the job. In order
to detect the presence of harmful biological agents, a sensor must
be able to identify a pathogen at a measurement of parts per trillion.
Technology available during the Gulf War only allowed measurements to the
parts per billion.
Photo: Purple chains of
anthrax bacilli © C. James Webb, 1994
The new sensor was developed by William Velander a biochemical engineer
who heads Virginia Tech's Pharmaceutical Engineering Institute, along with
Kent Murphy, a fiber optics expert and a member of the electrical engineering
department of the same institution. The device has shown results 20 times
more powerful than previous sensing devices.
Velandar and colleagues adapted a technology he invented to purify pharmaceuticals
present in blood plasma at trace levels. By combining his scientific process
with an optical fiber sensing device, Velander and Murphy have found that
they can "capture biological warfare agents" that were previously undetectable.
For example, the prototype biosensor detects endotoxin at a level that
is 20 times lower than previously achieved by other devices.
"Endotoxin is composed of compounds called lipopolysaccharides found
in bacteria such as E.coli. The presence of endotoxin from a blood borne
infection (sepsis) of a gram negative bacteria can cause clotting, organ
failure and subsequent death," Velander explains.
Velander estimates there are several hundred weaponizable biological
agents (WBAs) in existence that could induce battlefield and civilian casualties
that can. These can now be detected. "The new biosensor approaches the
sensitivity of a dog sniffing airborne chemicals," Velander adds.
Another advantage of the new sensor is its speed. Current technology
for detecting certain pathogens, in addition to being less sensitive, is
also time consuming. It typically requires an hour or more of laboratory
based effort. This new biosensor produces its finding in close to "real
time," Velander says, or in just a few seconds.
The sensor is now available only in prototype form. The researchers
hope to develop a belt pack size, battery generated portable device,
capable of being taken onto a battlefield.
Murphy and Velander envision other applications, including pharmaceutical
manufacturing, environmental monitoring, medical diagnostics, drug discovery,
and process control.
"One of the biggest applications will be in the drug discovery work,"
Murphy says. It can take six to nine months to screen libraries of new
chemicals, but with the new sensor, configured in an array of 100 fibers,
a determination could be made within a few weeks. A typical library can
contain between 10,000 and 10 million compounds from which to choose a
new drug. "This application is extremely exciting," Murphy adds.