MIT chemical researchers are working on a technique to use microparticles that can be read by smartphones to thwart counterfeiting.
"The particles, which are invisible to the naked eye, contain colored stripes of nanocrystals that glow brightly when lit up with near-infrared light," the MIT said.
MIT chemical engineering professor Patrick Doyle, who led the research, said these particles can withstand extreme temperatures, sun exposure, and heavy wear, and can be manufactured easily and embedded into various materials.
Such particles can be incorporated directly into 3-D-printed objects, or even on currency, or be incorporated into ink that artists could use to authenticate their artwork.
Also, the particles can “record” their environments such as when a refrigerated vaccine has ever been exposed to temperatures too high or low.
MIT cited a 2013 United Nations report indicating two to five percent of all international trade involves counterfeit goods.
Such products may include electronics, automotive and aircraft parts, pharmaceuticals, and food, it said.
Cheap
The MIT said the particles have an advantage as they do not need an expensive decoder like those required by present anti-counterfeiting technologies.
"Using a smartphone camera equipped with a lens offering twentyfold magnification, anyone could image the particles after shining near-infrared light on them with a laser pointer," it said.
It added the researchers are working on a smartphone app that would further process the images and reveal the composition of the particles.
200 microns long
MIT said the new particles are about 200 microns long and include stripes of different colored nanocrystals, known as “rare earth upconverting nanocrystals.”
It said 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," it said.
Particles with a mere six stripes can have one million possible color combinations, and the number can be exponentially enhanced by tagging products with more than one particle.
Researchers manufactured the particles using stop-flow lithography, a technique earlier developed by Doyle.
“It’s really a massive encoding capacity,” said lead author Paul Bisso, who started this project while on the technical staff at Lincoln Lab.
“You can apply different combinations of 10 particles to products from now until long past our time and you’ll never get the same combination,” he added.
“What separates our system from other anti-counterfeiting technologies is this ability to rapidly and inexpensively tailor material properties to meet the needs of very different and challenging requirements, without impacting smartphone readout or requiring a complete redesign of the system,” he said.
Jennifer Lewis, a professor of biologically inspired engineering at Harvard University who was not involved in the research, added the use of these upconverting nanocrystals is "quite clever and highly enabling.” — Joel Locsin/VC, GMA News
source: gmanetwork.com
