Cornell University has a group called “Fiber Science and Apparel Design” and the people working there are busy developing what I refer to as a nano-shmata.
Imagine that you are about to fix up dinner and want to make sure the area is clean. Take a specially designed napkin that has been mixed with nanofibers. These super-nanos are sensitive to a specific substance. In this case, (in preparation for food), the napkin is looking for e-coli. Wipe the table with the napkin and if the nasty germs are on the preparation area the nanofibers will change color. This alerts you to blowtorch the affected area. Well, some disinfectant will probably do the job.
If you happen to work at the Post Office in America having some nano-shmatas that would locate anthrax sure might be nice. The user could be very thorough about clearing an area of a specific biohazard by rubbing it with a new napkin until no nasty stuff appears. It may be possible to make everyone’s home a “white room”. I KNOW my mother would love this!