Nanotechnology offers vastly improved fingerprint acquisition

With the spate of Crime Scene Investigation shows currently running on television networks around the world, it’s hard not to be impressed with the evidence that technology can uncover. Well the science of fingerprinting looks set to move to a whole new level in the near future thanks to refinements to the fingerprinting process offered by two developments in nanotechnology. Described as revolutionary by people who are not prone to exaggeration (the United States Secret Service), the new nanotechnologies will enable fingerprints to be clearly developed that current techniques cannot detect.

The news is reported in the latest edition of the Royal Society of Chemistry journal Chemical Communications.

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 chemically react to 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 and suspending them in petroleum ether.

The prints produced using the new solution are very high quality and are developed after just three minutes immersion time.

The team have also extended their technique for use on non-porous surfaces, using a petrol ether suspension of cadmium selenide/zinc sulphide. In this case, the chemical reaction makes the prints fluoresce, so no additional developing stage is required.

Antonio Cantu, an expert in forensic science for the United States Secret Service in Washington, said: “The techniques are revolutionary and are apt to greatly improve the recovery of latent prints on evidence.”

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 Royal Society of Chemistry is the UK Professional Body for chemical scientists and an international Learned Society for the chemical sciences with some 43,000 members worldwide. It is a major international publisher of chemical information, supports the teaching of chemical sciences at all levels and is a leader in bringing science to the public.