According to a 2013 United Nations report 2 to 5 percent of all international trade involves counterfeit goods. These illicit products—which include electronics, automotive and aircraft parts, pharmaceuticals, and food—can pose safety risks and cost governments and private companies hundreds of billions of dollars annually.

Many strategies have been developed to try to label legitimate products and prevent illegal trade—but these tags are often too easy to fake, are unreliable, or cost too much to implement, according to MIT researchers who have developed a new alternative.

Led by MIT chemical engineering professor Patrick Doyle and Lincoln Laboratory technical staff member Albert Swiston, the researchers have invented a smartphone-readable particle that they believe could be deployed to help authenticate currency, electronic parts, and luxury goods, among other products. The particles, which are invisible to the naked eye, contain colored stripes of nanocrystals that glow brightly when lit up with near-infrared light.

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