THE police could have a new ally – a reliable technique for revealing fingerprints on porous surfaces.
At the moment, prints on surfaces like paper are revealed by adding a watery suspension of gold nanoparticles that stick to skin oils. Add a silver solution and the gold catalyses a reaction, leaving the print outlined in a black silver compound. But the nanoparticles can clump together, leaving uneven, inaccurate prints.
Now Daniel Mandler and colleagues at the Hebrew University of Jerusalem, Israel, have found a way to keep the gold particles separated, by adding long-chain carbon molecules to them, and suspended them…
