When it comes to detecting a wide range of extremely faint scents, including the primary vapor that emanates from TNT-based explosives, dogs are the gold standard. But researchers out of the University of California at Santa Barbara, report in the journal Analytical Chemistry that they just may have man's best friend beat -- in the form of a fingerprint-sized silicon microchip.
"Like a person, a dog can have a good day or a bad day, get tired or distracted," Carl Meinhart, a mechanical engineering professor who led the research, said in a school news release. "We have developed a device with the same or better sensitivity as a dog's nose that feeds into a computer to report exactly what kind of molecule it's detecting."
It could also be pointed out that a dog is larger than this device, requires food and training, and is, of course, mortal. Improving on its nose, however, is no easy task.
When the team put their device to the test, they found that, like dogs, it could detect tiny airborne molecules of 2,4-dinitrotoluene, the main chemical found in TNT-based explosives. They say that in theory it should also be able to (like a dog) detect a wide range of trace molecules that could help sniff out narcotics and even diseases.
The tech, which has been packaged on a silicon microchip roughly the size of a human fingerprint, captures and identifies molecules using what is called free-surface microfluidics and surface-enhanced Raman spectroscopy (SERS). Once vapor molecules are absorbed into a microscale channel of liquid, they mix with nanoparticles that, when hit with laser light, amplify their spectral signature. A computer database of these signatures can, in turn, identify the molecule.
"The paper we published focused on explosives, but it doesn't have to be explosives," said chemistry professor and co-author Martin Moskovits. "It could detect molecules from someone's breath that may indicate disease, for example, or food that has spoiled."
The team has already patented their tech and licensed it to SpectraFluidics, which a fellow researcher founded in 2008 and which was the recipient of a $1.3 million contract from DHS Transportation Security Administration earlier this year.