http://news.yahoo.com/s/ap/20061012/ap_on_sc/sensor_development
SOCORRO, N.M. - New Mexico Tech researchers have developed a sensor that uses the light-emitting properties of some nanoparticles to analyze and identify individual components of single strands of DNA and RNA.
The article is about more medical uses but i’m sure we can make it a weapon or have some time travel use for it 
TheCigMan