A new detector so sensitive it can pick up a single molecule of an explosive such as TNT has been developed by researchers at MIT.

Chemical engineers coated carbon nanotubes with protein fragments normally found in bee venom. When a target (including nitric oxide, hydrogen peroxide, and toxic agents such as the nerve gas sarin) binds to the bee-venom proteins coating the nanotubes, it shifts the nanotubes’ natural fluorescent light wavelength. The researchers built a new type of microscope to read the signal.

This type of sensor, the first of its kind, is easier to work with than other existing carbon-nanotube sensors because it is not influenced by ambient light, the researchers said.

Daniel A. Heller, George W. Pratt, Jingqing Zhang, Nitish Nair, Adam J. Hansborough, Ardemis A. Boghossian, Nigel F. Reuel, Paul W. Barone, and Michael S. Strano, Peptide secondary structure modulates single-walled carbon nanotube fluorescence as a chaperone sensor for nitroaromatics, PNAS, May 9, 2011 DOI: 10.1073/pnas.1005512108