LSU Research | Spring 2004

NANO LIFE SAVERS
New device uses nanoparticles to detect anthrax and other biological agents

Pull a hair from your head and examine it. The diameter of a typical human hair is 100 micrometers. One micrometer is one-millionth of a meter and equals 1,000 nanometers. After doing the math, you will find that one nanometer is equal to one-millionth the width of a single strand of hair. Imagine a particle that small detecting biological agents and potentially saving your life.

Researchers at LSU's J. Bennett Johnston, Sr., Center for Advanced Microstructures & Devices are harnessing the power of nanotechnology to develop a handheld device about the size of a palm pilot to detect anthrax, as well as other biological agents and household germs.

"Our focus is to fabricate a handheld device for detection of any biological agent," says Challa Kumar, leader of CAMD's nanofabrication research group. "Laboratory methods are available to detect biological agents very close to the single molecular level. However, translating these into a handheld device is extremely difficult. Our current efforts are in this direction.”

Since the anthrax scare of 2001, funding has increased to various federal agencies for research on biological agent detection. The Defense Advanced Projects Research Agency, the research arm of the U.S. Department of Defense, which is funding CAMD's project, has an entire technology research thrust in biological warfare defense.

Specifically, a nanoparticle can consist of just about any substance, metallic or nonmetallic. Kumar and his team begin with a cobalt nanoparticle and surround it with a thin gold layer and a special thiol, which is a sulfur-containing compound. The unique chemistry of the thiol used here attracts it to anthrax molecules. Different compounds would be used to identify different biological agents other than anthrax.
The device CAMD is constructing contains a series of interchangeable trays that would extract molecules from humidity in the air. Their engineered nanoparticles would be introduced into the sample and attach themselves to any anthrax molecules, which the device would then separate from all other molecules in the sample.

Now that only the anthrax molecules and their "captors" remain, the device initiates a final test to determine whether the sample poses a threat to human life. A giant magnetoresistance sensor, or GMR, is used to detect the magnetic fields of the cobalt nanoparticles, which have the anthrax attached to them clutched by the surrounding sulfur compound.

Josef Hormes, director of CAMD, stresses that one of the greatest features of the device the center is creating is its flexibility to be applied to other functions outside of biological warfare.

"This device can not only be used to detect anthrax, but any biological agent in any place," says Hormes. "It's very possible that kitchen appliances in the future, for example, could have such devices on them to detect salmonella or other household germs."

ON THE WEB:
Defense Advanced Research Projects Agency (DARPA)
LSU Center for Advanced Microstructures & Devices

from Spring 2004 Issue