Fingerprints Could Glow for Future Forensics
That classic TV crime drama scene where the plucky forensic scientist dusts for fingerprints may become a thing of the past. Researchers from China’s Zhejiang University in Hangzhou have created a technique that makes fingerprints — both old and new — glow in exquisite detail without destroying them.
The method enlists electrochemiluminescence, a phenomenon that causes a chemical solution to light up when hit with an electrical charge.
A fingerprint is pressed onto an electrode that's either in the form of indium tin oxide glass or a stainless steel sheet. The electrode is dipped into a specialized chemical solution. Oils, dirt and other particles in the fingerprint inhibit the electrochemiluminescence reaction, but the reaction could occur in the spaces in between. When a suitable voltage is applied to the electrode, the bare electrode surface, including the fingerprint's grooves, light up and can be imaged using a CCD camera sensor. A different chemical solution that sticks to the amino acids of the fingerprint does the opposite, causing the fingerprint's ridges to light up and not the areas in between.
Making the substrate glow produces a negative image; making the fingerprint glow produces a positive image. In either one, fine details in the fingerprints, like ridge patterns, branches and ends of lines and even pore size can be seen through this process.
The researchers tested this in a lab, but Bin Su said that the technique could be used in real life: "Fingerprints on real life substrates can be transferred by lifting them from the substrates to electrodes using a special tape. The process is simple and handy." Su said that his team also experimented with transferring fingerprints from different substrates including a coin, a desk, a computer screen and a disk.
The researchers also found that their method could be used to determine whether the owner of the fingerprint had been using drugs. Because the signature of metabolized drugs are secreted through the pores in the hand, a solution designed to reveal them could be used to analyze the fingerprint for illegal substances.
This process is still being tested and isn’t ready for real-life implementation yet. Which gives studios plenty of time to adapt it into their next crime scene investigation show…CSI: China, anyone?
Credit: Paul Taylor/Corbis