July/August 2007

Building a Better Dog's Nose

Chemist Timothy Swager wins Lemelson-MIT Prize for sensitive sensors.

By Sandra Swanson

Professor Timothy Swager holds Fido, which can sniff out explosives. Credit: Courtesy of the Lemelson-MIT Program

With 13 U.S. patents to his credit--and another 16 pending--Timothy Swager isn't short on imagination. But he had trouble getting his mind around the news that he'd won the $500,000 Lemelson-MIT Prize for inventiveness.

"I was blown away," says Swager, the head of MIT's chemistry department. "I quite frankly couldn't believe it and was pinching myself for a few days."

The Lemelson-MIT Program honors inventions that address real-world problems--like Swager's work with fluo­rescent polymers that bind with and detect molecules of TNT. (See "Sniffing Out Explosives," September 2005.) MIT (which owns the relevant patent) licensed the technology to Nomadics (now part of ICx Technologies), which used it in a highly sensitive bomb-­detection device called Fido. In field tests, Fido's detection ability was comparable to that of bomb-sniffing dogs and sometimes better. That's a real achievement, considering the power of canine noses: a dog's sense of smell can be 100 to 1,000 times as acute as a human's, depending on the odor and conditions, says Larry Myers, an associate professor at Auburn University's College of Veterinary Medicine.

"U.S. troops in Iraq have been using [Fido] pretty actively," Swager says. A handheld version can detect TNT vapor on people, clothing, and cars, and a robot-mounted version investigates roadside objects. Fido's ability to help soldiers identify bombs--and bomb makers--depends on a polymer chain that loses fluorescence when a TNT molecule strikes it at any point. ­Swager likens it to a string of holiday lights with one burnt-out bulb. The next step for Fido, he says, will be a device akin to Star Trek's tricorders, which can detect myriad substances.

Swager envisions a world with pervasive chemical sensors that aid civilians as well as soldiers. "We're entering an era where all of us will have more interest in detecting chemicals in our environment," he says. Those chemicals could be insecticides in groundwater, products of early-stage cancer cells, or trace amounts of nuts that could harm people who have allergies.

Swager's other inventions include a fluorescing dye, which could simplify screening for Alzheimer's disease, and a material that mimics human muscle. "I've always been interested in extending my science to the public sector," he says. "I'm committed to making the world a better place."