CounterfeitingTiny particles could help verify goods
Chemical engineers hope smartphone-readable microparticles could crack down on counterfeiting. Some 2 to 5 percent of all international trade involves counterfeit goods, according to a 2013 United Nations report. 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. Researchers have invented a new type of tiny, 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.
Cell phones to aid in stopping counterfing // Source: grapestech.com
Chemical engineers hope smartphone-readable microparticles could crack down on counterfeiting.
Some 2 to 5 percent of all international trade involves counterfeit goods, according to a 2013 United Nations report. 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 new type of tiny, 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.
These particles can easily be manufactured and integrated into a variety of materials, and can withstand extreme temperatures, sun exposure, and heavy wear, says Doyle, the senior author of a paper describing the particles in the 13 April issue of Nature Materials. They could also be equipped with sensors that can “record” their environments — noting, for example, if a refrigerated vaccine has ever been exposed to temperatures too high or low.
The paper’s lead authors are MIT postdoc Jiseok Lee and graduate student Paul Bisso. MIT graduate students Rathi Srinivas and Jae Jung Kim also contributed to the research.
“A massive encoding capacity”
The new particles are about 200 microns long and include several stripes of different colored nanocrystals, known as “rare earth upconverting nanocrystals.” These crystals are doped with elements such as ytterbium, gadolinium, erbium, and thulium, which emit visible colors when exposed to near-infrared light. By altering the ratios of these elements, the researchers can tune the crystals to emit any color in the visible spectrum.
To manufacture the particles, the researchers used stop-flow lithography, a technique developed previously by Doyle. This approach allows shapes to be imprinted onto parallel flowing streams of liquid monomers — chemical building blocks that can form longer chains called polymers. Wherever pulses of ultraviolet light strike the streams, a reaction is set off that forms a solid polymeric particle.
