Finding fingerprints at a crime scene has been a staple of forensic police work for decades, but now a new development could help reveal hidden fingerprints.
The current method for revealing prints involves coating surfaces with a watery suspension of gold nanoparticles and citrate ions. Under acid conditions, the gold particles stick to the positively charged particles in the print. The print is then developed using a solution of silver ions, which leave an outline of silver along the ridges of the print.
However, the gold solution used in this method is unstable and results are difficult to repeat – so Dr Daniel Mandler, Dr Joseph Almog and their team at the Hebrew University of Jerusalem, Israel, have developed a more stable solution be adding hydrocarbon chains to the gold nanoparticles.
They have managed to make the print fluoresce – by suspending the gold particle/hydrocarbon chain complex in petroleum ether – removing the need for an additional developing stage.
Dr Claude Roux, director of the Centre for Forensic Science at the University of Technology, Sydney, Australia, said: “This use of nanotechnology in the fingerprint community can bring novel and practical solutions to develop and enhance latent fingerprints that would otherwise remain undetected.”
The prints produced using the new solution are very high quality and are developed after just three minutes immersion time.
The work is reported in journal Chemical Communications.