May 10, 2011 14:05 GMT  ·  By
A new sensor developed at MIT can react to even the smallest quantities of nitro-aromatic compounds
   A new sensor developed at MIT can react to even the smallest quantities of nitro-aromatic compounds

A group of chemical engineers at the Massachusetts Institute of Technology (MIT) announces the development of an extremely advanced sensor, which has the capability to detect even a single molecule of explosives such as trinitrotoluene (TNT).

The combination of materials that was needed to create the new sensors is just as weird as the devices themselves. Scientists used hollow, single-walled carbon nanotubes (CNT) as a basis, and protein fragments derived from bee venom as a coating.

This mix, says MIT team leader and chemical engineer Michael Strano, proved tremendously effective at creating an extremely sensitive detection instrument, which can react to even the smallest quantities of nitro-aromatic compounds.

TNT is a member of this class of chemicals, scientists say, as are several other explosives. According to the MIT, the new instrument is considerably more effective than the spectrometry-based tools currently used in public buildings and airports.

“Scientists have studied these peptides, but as far as we know, they’ve never been shown to have an affinity for and recognize explosive molecules in any way,” the team leader says, referring to protein fragments called bombolitins.

“Ion mobility spectrometers are widely deployed because they are inexpensive and very reliable,” adds the expert, who is also the Charles (1951) and Hilda Roddey Career Development associate professor of chemical engineering at the Institute.

“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,” he goes on to explain.

Details of the work were published in this week's online issue of the esteemed journal Proceedings of the National Academy of Sciences (PNAS). The study's lead author was Daniel Heller, a former MIT graduate student who is now a fellow at the David H. Koch Institute for Integrative Cancer Research.

“Compounds such as TNT decompose in the environment, creating other molecule types, and those derivatives could also be identified with this type of sensor,” Strano says further.

“Because molecules in the environment are constantly changing into other chemicals, we need sensor platforms that can detect the entire network and classes of chemicals, instead of just one type,” he reveals.

The new sensor should enable the precise and reliable detection of dangerous compounds, and it may soon see action in airports and other security check-points.

“It doesn’t mean that we are ready to put these onto a subway and detect explosives immediately. But it does mean that now the sensor itself is no longer the bottleneck,” Strano explains.

“If there’s one molecule in a sample, and if you can get it to the sensor, you can now detect and quantify it,” the scientist concludes.