Our favorite ultra-skinny molecules have performed a lot of useful functions over the years, but keeping fruit flies away was never one of them. Now MIT scientists, with US Army funding, have discovered a way to give these nanotubes the canine-like sense of smell needed to stop produce spoilage and waste. Doping sheets of them with copper and polystyrene introduces a speed-trap for electrons, slowing them and allowing the detection of ethylene gas vented during ripening. A sensor produced from such a substance could be combined with an RFID chip, giving grocers a cheaper way to monitor freshness and discount produce before it's too late. If that works, the team may target mold and bacteria detection next, giving you scientific proof that your roommate needs to wash his socks.