Nanoparticles reveal fingerprints
According to Chemical Science, Israeli researchers have found new ways to use nanotechnology to reveal hidden fingerprints. They've used gold nanoparticles suspended in a stable solution of petrol ether. The nanoparticles "stick to the fingerprint residues through hydrophobic interactions." This new method produces high quality prints in just three minutes. Other experts in forensic science confirmed the results, but it's still unknown when -- or if -- law-enforcement forces will use this technology.
Before going further, below is a comparison between two halves of a sebum-rich (sebaceous) fingermark on paper. The one on the top has been developed with what is known as a "Silver Physical Developer" (Ag-PD). On the bottom, the much clearer image has been obtained with a petroleum ether solution of gold nanoparticles (Au-NPs) stabilized with octadecanethiol (Au-NP-C18) and followed by Ag-PD (Credit: The Hebrew University of Jerusalem).
This research has been conducted at The Hebrew University of Jerusalem by Daniel Mandler, professor at the Institute of Chemistry and his colleagues. But what exactly have these researchers found?
[They] have replaced the traditional gold solution with a more stable equivalent. Their gold nanoparticles bristle with long hydrocarbon chains and are suspended in petrol ether. They stick to the fingerprint residues through hydrophobic interactions, and can be developed with silver as before, producing high quality prints after just three minutes immersion time.
The team has also developed a fingerprinting method for non-porous surfaces, using a petrol ether suspension of cadmium selenide/zinc sulphide nanoparticles stabilised by long chain amines. As with the team's gold solution, the nanoparticles adhere to the fingerprint by hydrophobic interactions. But in this case, as the nanoparticles fluoresce under UV light to reveal clear fluorescent prints, no additional developing stage is needed.
This research work has been published by Chemical Communications under the name "Application of nanoparticles for the enhancement of latent fingerprints" (2007 issue, Pages 1142-1144). Here are two links to the abstract and to the original paper (PDF format, 3 pages, 427 KB) from which the above image has been extracted.
Now it remains to be seen when this technology starts to be used in the CSI TV series -- and in the real world.
Sources: Vikki Chapman, Chemical Science, March 12, 2007; and various websites
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