Why do we still use dogs to sniff out dangerous explosives at the airport? That’s because even with all the modern science and technology available, man’s best friend continues to be the best at it. Things may change, as researchers at the University of California in Santa Barbara have now developed a device that may rival a dog’s olfactory ability. Their nanotech device is inspired by the biology of canine scent receptors. It uses microfluidics to detect airborne molecules of TNT explosives and distinguish them from similar molecules. The results of the research were published in Analytical Chemistry.
A dog’s nose is more sensitive than a human nose and can pick up the scent of explosives very well. A dog however, is an animal, and the sensitivity of its nose can be disturbed by fatigue or distraction. This is a characteristic that computers and devices don’t share with living beings. That is what brought Carl Meinhart and Martin Moskovits to the idea of developing a device that is as sensitive as a dog’s nose in picking up TNT vapors.
Packaged on a fingerprint-sized silicon microchip and fabricated at UCSB’s state-of-the-art cleanroom facility, the underlying technology combines free-surface microfluidics and surface-enhanced Raman spectroscopy (SERS) to capture and identify molecules. A microscale channel of liquid absorbs and concentrates the molecules by up to six orders of magnitude. Once the vapor molecules are absorbed into the microchannel, they interact with nanoparticles that amplify their spectral signature when excited by laser light. A computer database of spectral signatures identifies what kind of molecule has been captured.
The current device detects the scent of TNT, but the technology may also be used to developed devices capable of ‘smelling’ any other airborne molecule, even ones undetectable by human or even canine noses. Here’s video further explaining the workings of the technology:
Article in Analytical Chemistry: Free-Surface Microfluidics/Surface-Enhanced Raman Spectroscopy for Real-Time Trace Vapor Detection of Explosives
UC Santa Barbara: Nanotech Device Mimics Dog’s Nose to Detect Explosives