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For biological threats, a nanodefense

Researchers use nanopulses to probe the cell’s electromagnetic behavior.

Xuanhong Cheng, assistant professor of materials science and engineering, investigates how cells respond to environmental stimulation.

James Hwang, professor of electrical and computer engineering, is one of a handful of researchers in the world who use high-frequency nanopulses to drill through cell membranes and measure electrical signals.

Together, they are working to achieve compact and fast DNA sequencing from a single cell. This could lead to the development of a hand-held device capable of identifying the presence of biological threats and thus saving lives.

Their project is funded by the Defense Threat Reduction Agency of the U.S. Department of Defense.

In the short term, Cheng and Hwang want to analyze the high-frequency nanopulses to gain a better understanding of the electromagnetic interaction at the cell membrane. Their ultimate goal is to produce a “lab on a chip” that can integrate the nanopulses with a microprocessor on a device like a cell phone.

Cheng, an expert in microfluids, helps develop small medical devices that automate the diagnosis of disease; one of these monitors the progress of HIV. In the project with Hwang, she is using human cancer cells. After she immobilizes a cell on a microchip, Hwang sends nanopulses through the cell membrane. The resulting electrical charge pulls a strand of DNA through the membrane like a thread being coaxed through the eye of a needle.

As the strand is pulled, the researchers use computers to measure the electrical resistance and capacitance. This enables them to identify the cell’s origin. Knowing if the cell is from a biological pathogen, or whether the cell is alive or dead, is essential information.

“You can’t take microscopes and labs onto the battlefield,” Hwang says. “The idea is to pack this process onto a chip and pack the chip into a cell phone.”

“The phone would suck samples from the air,” says Cheng, “and send the electrical pulse through the samples. A built-in signal processing microchannel would analyze the electrical information.”

Knowing whether the cell is alive or dead is important, says Cheng, because there are all kinds of spores in the environment, some of them pathogens, but they are harmless if they are no longer alive.

Cheng and Hwang have received $500,000 in seed funding to prove the concept.