At the beginning of september, MIT chemist Timothy Swager and several of his students were set to travel to the United States Army's Fort Leonard Wood in Missouri to try their skill at detecting land mines. It's only a preliminary test and the mines were deactivated. But the scientists were armed with a portable device that incorporates a novel conducting polymer-and a clever molecular detection scheme-that could trigger a breakthrough in chemical sensing.

Land mines continue to be a menacing presence around the world, and methods for quickly and safely spotting them remain woefully inadequate. Indeed, dogs are still one of a soldier's most reliable friends in sniffing out the deadly devices. Metal detectors often turn up false alarms. More sophisticated and expensive analytical instruments tend to be bulky and can have trouble picking up the "smell" of land mines.