Michael Strano and co-workers, Massachusetts Institute of Technology, USA, have developed a new sensor for trace explosives in the air.

They coated carbon nanotubes with peptides from the bombolitin family, found in bee venom. When a nitroaromate binds to the bombolitin, the modulation of the secondary proteine structure is reported by changes of the single-walled carbon nanotube. The nanotubes’ natural fluorescence shifts wavelength. The sensor was coupled with a split-channel microscope to detect the near-infrared photoluminescence in real time.

The device is more sensitive than ion mobility spectrometers, commonly used at airports. The mechanism ilustrates that functionalization of the carbon nanotube surface can result in completely unique sites for recognition, resolvable at the single-molecule level.

• Peptide secondary structure modulates single-walled carbon nanotube fluorescence as a chaperone sensor for nitroaromatics
  D. A. Heller, G. W. Pratt, J. Zhang, N. Nair, A. J. Hansborough, A. A. Boghossian, N. F. Reuel, P. W. Barone, M. S. Strano,
  Proc. Natl. Acad. Sci. 2011.
  DOI: 10.1073/pnas.1005512108