Sensor Developer Awarded Lemelson-MIT Prize

Timothy M. Swager has a nose for explosives. The chemistry professor and department head at the Massachusetts Institute of Technology (MIT) claims he can "almost always take a whiff of a chemical and make a pretty good guess as to what class a volatile compound might be in."

But Swager's nose is nothing compared to the amplified chemical sensors he invented to detect vapors of common bomb-making chemicals, such as TNT.

Timothy Swager (Photo courtesy MIT)

For his entire body of inventive work, the Lemelson-MIT Program named Swager the 2007 winner of the $500,000 Lemelson-MIT Prize, the most prestigious cash prize for invention in the US. This year, the prize criteria were modified to specify the winner be a mid-career inventor who is rising in his or her field.

"The originality, practicality and timeliness of Dr. Swager's inventions made him a standout candidate for this year's $500,000 Lemelson-MIT Prize," said Merton Flemings, director of the Lemelson-MIT Program, which has given the award to an accomplished inventor for the past 12 years. "For instance, soldiers and Marines in Iraq are already benefiting from his explosive-detection inventions, and his molecular wire inventions will likely find application in a wide range of health-care, environmental and security areas."

Swager and his colleagues invented amplifying fluorescent polymers that can attract nitro aromatic molecules, a class of chemicals typically used in explosives. In most molecular sensors, the strength of the emitted signal is proportional to the number of target molecules reaching the sensor. Therefore, they are usually not sensitive enough to detect very small trace amounts of the target substance.

Swager reasoned that if he designed a polymer chain that would carry a signal except when a single target molecule struck the chain, he would have an extraordinarily sensitive detector. Thus, if the target molecule were TNT, a bomb detection device could be constructed from the polymer.

"Imagine a string of holiday lights," Swager said. "If I break one bulb, then that strand goes down. Moreover, imagine if I wire a bunch of strands together. If I break a single bulb in any one of them, then that brings the whole thing down. That broken bulb represents the TNT molecule or vapor you're trying to find. The interruption tells you something's there."

The TNT molecules can bind anywhere along the polymer chain.

"It's random where the TNT will bind," Swager said, "so you give it as many opportunities to bind as it can possibly want."

In 2001, Swager licensed his patented polymer technology to Nomadics, now a unit of ICx Technologies, for use in that company's Fido explosives detector, named for its ability to simulate a bomb-sniffing dog.

"Fido doesn't have the computational power or the agility of a dog, but it has a similar sensitivity for certain things," Swager said. "Within some classes of chemicals, it can actually smell as well as a dog, which is important." Dogs also need trainers, can act unpredictably in unfamiliar environments and can intimidate people, which Swager cites as other advantages of Fido.

Currently, American soldiers in Iraq are using Fido devices in two ways: either attached to a robotic platform for deployment to hard-to-reach and dangerous areas, or as a portable, handheld monitor to analyze people, clothing and automobiles.

In 2005, Fido earned the US Army's Greatest Invention Award. General (Ret.) Paul J. Kern, ae former US Army senior military advisor in Research, Development and Acquisition, wrote in a nomination letter for Swager, "It is not realistic to put a number on how many attacks have been prevented by early detection of bomb makers and IED's, but one could easily estimate that hundreds of individuals have avoided serious injury or death as a result of Swager's chemical inventions."

In addition to its use in Iraq, Fido has also been tested domestically. The National Park Police used handheld units to screen bags on the Washington DC Mall during the July 4 celebration in 2006. Swager envisions the device also having applications in airports and building security.

In addition to their use in explosives detection, Swager's molecular wire sensors have many other possible applications, from detecting environmental pollutants to early-stage cancer cells.

Some of his other inventions include lasing sensors that could someday improve building security; near-infrared optical imaging agents that may enable simpler techniques for screening and diagnosing Alzheimer's disease; as well as molecules with high-free volume that could improve the manufacture of semiconductors and liquid crystal displays.

As an educator and researcher, Swager is widely recognized a role model for young innovators. He also serves on numerous government committees and task forces. He is a standing member of the National Research Council's Committee on Operational Science and Technology Options for Defeating Improvised Explosive Devices and is currently in a working group that advises the Joint Improvised Explosive Device Defeat Organization (JIEDDO). Swager also co-wrote the proposal that established the Institute for Soldier Nanotechnology at MIT and was its initial associate director.

In addition to honoring Swager with the $500,000 Lemelson-MIT Prize, the Lemelson-MIT Program also announced the inaugural winner of its new $100,000 Lemelson-MIT Award for Sustainability. Lee Lynd, professor of engineering and adjunct professor of biology at Dartmouth College and co-founder of Mascoma Corp., received the award for a body of inventive work related to the conversion of plant matter into ethanol for fuel.
From May 2-5, Swager and Lynd will join the Lemelson-MIT Program for the first-ever EurekaFest, a celebration designed to empower a legacy of inventors through activities that inspire youth, honor role models and encourage creativity and problem solving. EurekaFest is presented by the Lemelson-MIT Program in partnership with the Museum of Science, Boston.

For more information, visit: web.mit.edu/invent/eurekafest.html