Frey's group used electricity to create a fine mat of the PLA fibers--a technique known as electrospinning--and embedded biotin, a reactive B vitamin. The biotin carried antibodies for Escherichia coli, and the fibers changed color when the germ was detected. "It works with E. coli in either water or [on a] surface," says Frey, whose latest work will soon be published in the Journal of Membrane Science. "Right now, it's just one pathogen, but it has the possibility of hundreds."
The Cornell team can only detect pathogens they know to look for--so that they can attach the appropriate antibodies to the fibers--and have not determined exactly how low a concentration of bacteria they can detect. But the paperlike fabric shows great potential simply for its ease of use. "Anybody who knows how to use a napkin could use it," Frey notes. "You wouldn't need a trained chemist to detect biohazards." And Frey's group is evaluating other fiber compounds that actually attract water, unlike PLA. Such hydrophilia might boost efficacy and ease use even further. Perhaps in the near future, you'll reach for a tissue not just for a sneeze, but also to find out exactly what ails you.