One of the surprising things about living in the world of high technology, is that high-tech things don't always look radically different from low-tech things.
When I was a kid we all imagined that machines in the future would be enormous, complicated-looking contraptions with flashing lights and spinning dials, but some of the most modern equipment being designed today looks pretty mundane until you see what it can do.
Take the napkin announced by Cornell University researcher Margaret Frey. It looks, well, like a paper napkin. Where's the high-tech?
In fact, this napkin is made out of nanofibers, each one only 1/800th the size of a human hair. The nanofibers are specially coated with antibodies, making them act as tiny sensors for pathogens. A pathogen is just a biological agent that causes disease. Bring this napkin into contact with something dangerous, like E.Coli bacteria, and the fibers catch it. Now rinse them with a special solution and they turn color.
How do you bring it into contact with potential biohazards? Well, it's a napkin, so you wipe it across things. Maybe you use it to soak up spills. Maybe you pass it around eating areas. Anywhere there might be a risk of exposure, just wipe, rinse, and see what happens. Simple.
At the moment, the high-tech napkin has only been designed to test for a few infectious agents, but there's no reason it couldn't handle a whole series of threats. Maybe soon, when the doctor tells you to cough, it will be into an innocuous-seeming white napkin. Just hope it doesn't change color.