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Old 12-23-2008, 11:34 AM   #1314
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Aethyr Engineering

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Mitochondrial battery could sniff out explosives

A BIOELECTRONIC sensor the size of a postage stamp could sniff out bombs and other explosives.

Most commercially available explosives detectors tend to be expensive, bulky and complex - and hence difficult to use in the field. That may change thanks to a new sensor invented by Shelley Minteer and her colleagues at St Louis University in Missouri.

The detector is a spin-off from the Minteer group's work to develop fuel cells powered by mitochondria, the parts of cells that generate energy by burning a chemical called pyruvate. Produced by the digestion of sugars, pyruvate is the compound that starts the Krebs cycle - the complex series of chemical reactions in cells that releases energy as part of respiration.

The team had been working on a fuel cell that uses mitochondria bathed in pyruvate to generate an electric current, and devised a biological "off" switch in the form of a naturally occurring antibiotic called oligomycin, which hampers the oxidation of pyruvate. Adding oligomycin to the cell switches off the current.

Minteer and her colleagues found that if they then added trace amounts of nitrobenzene - a member of the same chemical family as many explosives - they could reverse the effect of oligomycin and switch the mitochondria back on. She says any chemically related explosive should do the same, and that the sensor is able to detect explosives in concentrations as low as 2 parts per trillion (Journal of the American Chemical Society, DOI: 10.1021/ja807250b).

"We should be able to detect all nitroaromatic explosives," says Minteer. "We are studying the other nitroaromatic explosives to determine what we can detect."

Timothy Swager, head of chemistry at the Massachusetts Institute of Technology, says the new device is "an elegant demonstration of a bioelectronic sensor".
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