Unfortunately, in modern day international trade 2-5% involves counterfeit products - United Nations (UN) report, 2013. Such fake products include electronics, automotive and aircraft parts, pharmaceuticals and food, which can pose safety risks and subsequent expenditure for governments and private companies can run up to billions of dollars per annum.
To date many strategies have been developed to try to "label" legitimate products and so prevent illegal trade. However, such tags are often too easy to fake, unreliable and cost too much to mass manufacture, as according a MIT researchers report who have developed an alternative process.
Lead MIT chemical engineer, Professor Patrick Doyle, and Lincoln Laboratory technical staff member Albert Swiston, have claimed to have invented a new type of tiny, smartphone-readable particle, which they believe can be used to help authenticate currency, electronic parts and luxury products. The particles are invisible to the naked eye, and contain coloured stripes of nanocrystals which glow brightly when lit-up with Near-|nfrared (NIR) light.
Doyle states that the particles can be easily manufactured and integrated into a variety of materials, which can withstand extreme temperatures, sun exposure and heavy wear and tear. Doyle as a senior author has presented such results in a paper describing the particles in Nature Materials. The researchers claim their sensor can also "record" their environments, for example, noting if a refrigerated vaccine was exposed to temperatures too high and/or too low.
A massive encoding capacity
The new particles are approximately 200 microns in length, and include several stripes of different colored nanocrystals which are typically known as rare earth unconverting nanocrystals. The crystals can be doped in elements, such as Ytterbium (Yb), Gadolinium (Gd), Erbium (Er) and Thulium (Tm), which can then emit visible colours when exposed to a NIR light. In addition, by altering the ratios of the elements, the researchers managed to tune the crystals to emit any colour into the visible spectrum.
The manufacturing process of the particles was accomplished by stop-flow lithography. Interestingly a technique developed by Doyle. The approach allows shapes to be imprinted on to parallel flowing streams of liquid monomers. Subsequently when pulses of ultraviolet (UV) light strike the streams - a reaction is set-off which forms a solid polymeric particle.
In this study - each polymer stream contains nanocrystals that emit different colours, thus, enabling the researchers to form striped particles. To date, the researchers have managed to create nine nanocrystals in different colours, but there is a distinct possibility to create many more.
Employing the process, above, the researchers can generate vast quantities of the unique tags. The particles which contain six stripes can have at least 1 million different possible colour combinations. Such a capacity can be enhanced by tagging products with more then one particle. For example, if the researchers created a set of 1,000 unique particles and then tagged products with any 10 of those particles than there would be enough to tag every grain of sand on Earth.
As stated by Bisso - "It's really a massive encoding capacity," Bisso started the project while on the technical staff at Lincoln Laboratory. He continues to state - "You can apply different combinations of 10 particles to products form now until long past our time and you'll never get the same combination."
A Harvard University Professor of Biologically, Jennifer Lewis, not involved in the research - states that - "The use of these unconverting nanocrystals is quite clever and highly enabling," She continues to state - "There are several striking features of this work, namely the exponentially scaling encoding capacities and the ultra low decoding false-alarm rate."
The micro-particles can be dispersed within electronic parts and/or drug packaging during the manufacturing process, which can be directly incorporated into 3D-printed objects, or printed on to currency. Plus, they could also be incorporated into ink whereby artists could use to authenticate their artwork.
The versatility of the approach was demonstrated by using two polymers with totally different material particles - one hydrophobic and one hydrophilic. The colour read-outs were the same with each, thus, suggesting that the process could easily be adapted on to many types of products that campanies might want to tag with these particles.
Bisso states - "The ability to tailor the tag's material properties without impacting the coding strategy is really powerful," - and - "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 read-out or requiring a complete re-design of the system."
An additional advantage to the particles is that they can be read without an expensive decoder like those required by most other anti-counterfeiting technologies. Using a smartphone camera equipped with a lens offering twenty-fold magnification means anyone could image the particles after shining NIR light on them with a laser pointer. A smartphone app is also being developed that process the images and reveal the exact composition of the particles. Original article available here
As with other MIT studies, the future potential of nanomaterials is clear to be seen. As stated previously, DCN Corp strongly believes it can supersede, by magnifying the signs of counterfeiting. Going forward, if you and/or your colleagues are interested in making DCN Corp's alternative process reality - please ensure to contact the company as soon as practicably possible.