Rambo Tribble writes: Researchers from the Worcester Polytechnic Institute, in Massachusetts, have developed nanoparticles with distinct melting points, which they suggest be used as forensic "barcodes" to identify the origins and integrity of things such as explosives and currency [PDF]. To demonstrate the technique, the researchers used the explosive, TNT, as a test case. Commenting on the viability of the approach, researcher Dr Ming Su said, 'The nanoparticle does not participate in any chemical reaction, and it will not effect the function of the existing object. The only thing it will do is to provide a thermal signature.' He added, 'Nanoparticles are so small, they can be put into any objects.' The BBC has more approachable coverage.