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Anthrax Sensor

By Sean Henahan, Access Excellence

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.

During 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.

Related information on the Internet
CDC: Anthrax Information
AE: Putting Anthrax to Work

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