Nanotechnology is adding a new weapon to the crime fighter's arsenal: a nano-solution for sharpening fingerprints.
For more than a century, crime investigators have sprayed suspect surfaces with a water-based gold or silver solution to detect fingerprints. The metal ions are reduced to a black precipitate along the lines of fatty deposits left by the skin ridges. But "even with the most advanced fingerprint techniques," says chemist Joseph Almog of Hebrew University in Jerusalem, "less than a third" of good prints at crime scenes produce usable evidence.
Almog, who is also a former chief forensic scientist for the Israel National Police, and fellow Hebrew University chemist Daniel Mandler have found that attaching hydrocarbons to gold nanoparticles is the key. The fat-seeking hydrocarbons guide the gold to the skin impression and lay down a metal trail. If this treatment is followed with the conventional solution, the gold catalyzes the precipitation of metal in solution, and the resulting fingerprints are far sharper, the scientists report in the current issue of Chemical Communications.
The new method could be "revolutionary" for crime fighting, says Antonio Cantu, chief forensic scientist for the U.S. Secret Service in Washington, D.C. But first, says Almog, it has to be refined, standardized, and field-tested in police labs.
