Scientists at the Massachusetts Institute of Technology coated carbon nanotubes -- hollow, one-atom-thick cylinders made of pure carbon -- with protein fragments normally found in bee venom, proteins known to react to a class of explosives known as nitro-aromatic compounds that includes TNT, an MIT release reported Tuesday.
The researchers say sensors based on this technology could be far more sensitive than existing explosives detectors, such as those used at airports, which use spectrometry to analyze charged particles as they move through the air.
"Ion mobility spectrometers are widely deployed because they are inexpensive and very reliable," chemical engineering Professor Michael Strano said. "However, this next generation of nanosensors can improve upon this by having the ultimate detection limit, [detecting] single molecules of explosives at room temperature and atmospheric pressure."
When the target molecule binds to the bee-venom proteins coating the nanotubes, it shifts the wavelength of the carbon nanotubes' natural fluorescence, which can be read by using a special microscope, since the fluorescence can't be seen with the naked eye.
By using several different nanotubes coated in different protein fragments, the researchers say, they can identify a unique "fingerprint" for each explosive they might want to detect.