Heads Up Potheads

A careless touch could be all police or insurance companies need to determine not only your identity, but also your past drug use, if you've fired a gun or handled explosives, even specific medical conditions.

The new technique attaches the iron oxide particles to antibodies and suspends them both in a liquid solution, which is then drizzled over a fingerprint. If the chemical that a specific antibody targets is present, the molecules latch onto it and glow.