Researchers at the University of Surrey (UK) have developed a new coating technology using “nanotags” designed to identify individuals who use firearms in the commission of a crime. The forensics tool involves labeling batches of cartridges with unique nanotags made of hard-to-remove pollen and a mixture of tiny grains of Zirconia, silica, and titanium oxide. Invisible to the naked eye, the nanotags attach themselves to the hands, gloves, and clothing of anyone who handles a cartridge. Traces of the tags remain on the spent cartridge casing. That direct link would provide more authoritative evidence than specks of gunpowder residue sometimes used to link suspects to fired weapons. By using many variations in the mixture of crystal and pollen grains, the researchers say they can produce large numbers of unique tags. “We decided to work with pollens because they have a unique structure, are resistant to temperature and are easily recognizable,” said lead researcher Paul Sermon. The nanotag materials are “also easily dispersed and carried around in clothes, skin, etc.,” he added. Pollen grains vary between plant species and are easily identified under a microscope. Chemical techniques could reveal which oxides were mixed with the pollen, and in which proportions, to determine which batch of cartridges they originate from. Sermon says the tags are designed to be compatible with current cartridge manufacturing processes and could be implemented within 12 months of receiving funding from companies or governments interested in using the technology. In addition to the tags, the researchers are working on a way to have gun cartridges retain skin cells from anyone who handles them, for later DNA-based forensic analysis. Micro-scale grit, they note, can effectively trap cells and protect DNA from the heat of firing. Today, cartridges are smooth and rarely retain DNA or fingerprints. The team is also looking to apply the same technique to knives. Go to: New Scientist Tech

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