How To Put A Police Dog On A Chip

Mem

o to man's best friend: In a few years, you may be relieved of your police drug-sniffing duties, thanks to a pair of Georgia Tech scientists. They have developed a handheld electronic nose that detects the presence of cocaine and other narcotics better than your cold, wet snout ever could.

The scientists — electrical-engineering professor William Hunt and chemistry doctoral candidate Desmond Stubbs — fused microelectronics and biotechnology to create a device that not only detects very small amounts of a substance but can also differentiate between one chemical and another. "I had seen some of the existing electronic noses and knew they weren't chemically specific, so I knew I had to figure out a way to get biotechnology onto a chip," says Hunt.

Though police dogs have played an important role in the $19 billion war on drugs, their noses simply aren't as keen as Hunt and Stubbs' creation, which can sniff out a few trillionths of a gram of an illegal substance. The two scientists say their device — which is still a prototype but will probably cost considerably less than the $80,000 worth of crime-lab equipment now being used for such tasks — makes economic sense. And because the artificial nose, according to Stubbs, "determines on the spot whether cocaine or other substances are present," it could also eliminate the need for scientists to do the analyses.

Most electronic noses have sensors that can detect the presence of a suspicious chemical by measuring the disturbance it causes in sound waves across a small quartz crystal. But just like a dog's nose, those electronic sniffers aren't able to determine whether the substance is cocaine or a compound with similarly sized molecules, such as caffeine. Stubbs addressed that problem by coating the sensor with an antibody that was similar in structure to cocaine. As a result, if cocaine were present in a room, it would attach to the antibody molecules and set off an electrical signal. Initial tests in the Georgia Bureau of Investigation labs have been a success. Still, Hunt says the portable nose won't be ready for use in airports for a few years. In the meantime, the pair may want to hire a public relations firm to deal with the potential issue of unemployed dogs.