Fingerprint Detection Technology Adds A Touch Of Fluorescence
October 25, 2013

Quicker, Less Expensive Fingerprint Detection Technology Pioneered In France

redOrbit Staff & Wire Reports - Your Universe Online

Researchers from the French National Centre for Scientific Research (CNRS) have developed a new, faster and less expensive method of detecting fingerprints by using fluorescence (the emission of light or other radiation from molecules that are bombarded by particles or by radiation from an external source).

The product used in this process, Lumicyano, was developed by CNRS and Crime Scene Technology and is detailed in a paper published online by the journal Forensic Science International. The patent-pending technique has already been successfully tested by the French Police, the US Federal Bureau of Investigation (FBI), Scotland Yard and other law-enforcement agencies, the inventors said in a statement.

“Fingerprints are essential evidence in numerous criminal investigations,” CNRS explained. If a criminal places their finger on an object, they can leave behind trace amounts of water, salts, fat, amino acids and perhaps even DNA. However, forensics experts can have difficulty using fingerprints as evidence if they are too light or too low in contrast, and techniques currently used to reveal them can be difficult at times.

Crime scene investigators use a method in which a cyanoacrylate compound (i.e. super glue) is fumed, reacting with the elements of the fingerprint, polymerizing, and leaving behind a white deposit that can be photographed and studied, the study authors said. However, fingerprints that are light in color and low contrast can be difficult to take pictures of, and sometimes the image quality cannot be properly exploited.

“In this case, crime scene investigators can opt for a second treatment using a colorant, which turns the fingerprint fluorescent. However, this post-treatment poses several problems,” officials from the French research center said. “The products in question are toxic and carcinogenic and have to be used in a fume cupboard, whose cost is usually beyond the means of most police stations. In addition, this process can require up to 48 hours and can degrade the fingerprints through leaching, which in most cases compromises the sampling of DNA.”

In an attempt to overcome those issues, several chemists have spent more than a quarter of a century attempting to develop a product which would allow fluorescent fingerprints to be directly detected. It is that product that the CNRS and Crime Scene Technology experts describe in their study. The technique uses a combination of cyanoacrylate with a molecule of a small fluorescent colorant from the tetrazine family.

“Tetrazine molecules are fumed along with the cyanoacrylate onto the fingerprint support and adhere to the deposit. In this way, using a simple UV lamp or forensic lighting techniques, the fluorescent traces are visible and can be photographed,” CNRS said. This technique provides “excellent detection performance” while also reducing costs and treatment times and not damaging the DNA that can sometimes be obtained through fingerprints, they added.

Image 2 (below): Bottle of Lumicyano(tm). Credit: © Crime Scene Technology