Researchers at Cornell University are developing a fancy-pants napkin that uses nanotechnology to detect bacteria and viruses on any surface it's wiped over. The napkin will contain nanofibers that are bound to certain antibodies, and when those antibodies latch on to specific elements the cloth will change colors. It could be used from detecting anything from E. Coli in meat to the flu virus on your kitchen table to cooties on your little sister's face. Once fully developed the technology won't be prohibitively expensive, allowing for the napkins to be used in any number of situations. The technology is still being developed and won't be around for a few years, but once it's finished it has the potential to help people detect stuff you don't want around much easier.