Researchers develop an invisible type of bar code to thwart criminals

June 6, 2014 by Bob Yirka
(A) Transmission electron microscope image and (B) Differential Scanning Calorimetry thermogram of silica encapsulated indium-tin nanoparticles. A library of barcodes formed by four types of phase change nanoparticles (indium, tin, bismuth and indium-tin-bismuth eutectic alloy). Credit: Ming Su, Worcester Polytechnic Institute

( —A team of researchers at Worcester Polytechnic Institute in Massachusetts has developed a type of bar coding system that would be almost impossible for criminals to thwart. As the team describes in their paper published in the journal Scientific Reports, the new system is based on adding certain types of nanoparticles to materials as part of the manufacturing process that can be read later using a special device.

Everyone is familiar with bar codes, they allow for quick scanning at checkout counters. But they are also used to track the movement of merchandise and in some cases, to prove that have been counterfeiting products. Unfortunately for manufacturers, printed bar codes are relatively easy to reproduce, thus, criminals can make their own, allowing them to proceed with their illicit activities. In this new effort, the researchers have come up with a way to allow for the creation of invisible bar codes that are nearly impossible to replicate after the fact.

The idea revolves around several types of , each of which has a unique melting point. Mixing the nanoparticles together allows for creating unique thermal signatures. To use the nanoparticles, manufacturers would simply add them into the mix when creating metals, papers and even fluids. The researchers say the addition of the nanoparticles doesn't change how a material looks, doesn't react with anything in it or impact how a finished product performs. Reading the new type of "" requires a device capable of performing differential scanning calorimetry (DSC)—a technique based on assessing the difference in the amount of heat required to heat different parts of a sample material. For criminals to circumvent the process they would have to somehow find out which nanomaterials were added to a product to create its unique thermal signature then add the right mix of to their own counterfeit product to recreate it—no easy feat.

The researchers claim their nanoparticle bar codes could be used with paper, metals, fluids and even drugs. As a demonstration, the team used their new technique on a sample of dinitrotoluene—one of the ingredients in TNT. They report being able to identify the thermal signature of the original mixture even after an explosion has occurred.

Explore further: Research team uses nanoparticles to make paper waterproof and magnetic

More information: Covert thermal barcodes based on phase change nanoparticles, Scientific Reports 4, Article number: 5170 DOI: 10.1038/srep05170

An unmet need is to develop covert barcodes that can be used to track-trace objects, and authenticate documents. This paper describes a new nanoparticle-based covert barcode system, in which a selected panel of solid-to-liquid phase change nanoparticles with discrete and sharp melting peaks is added in a variety of objects such as explosive derivative, drug, polymer, and ink. This method has high labeling capacity owing to the small sizes of nanoparticles, sharp melting peaks, and large scan range of thermal analysis. The thermal barcode can enhance forensic investigation by its technical readiness, structural covertness, and robustness.

Related Stories

Recommended for you

Graphene under pressure

August 25, 2016

Small balloons made from one-atom-thick material graphene can withstand enormous pressures, much higher than those at the bottom of the deepest ocean, scientists at the University of Manchester report.

Designing ultrasound tools with Lego-like proteins

August 25, 2016

Ultrasound imaging is used around the world to help visualize developing babies and diagnose disease. Sound waves bounce off the tissues, revealing their different densities and shapes. The next step in ultrasound technology ...

Nanovesicles in predictable shapes

August 25, 2016

Beads, disks, bowls and rods: scientists at Radboud University have demonstrated the first methodological approach to control the shapes of nanovesicles. This opens doors for the use of nanovesicles in biomedical applications, ...

'Artificial atom' created in graphene

August 22, 2016

In a tiny quantum prison, electrons behave quite differently as compared to their counterparts in free space. They can only occupy discrete energy levels, much like the electrons in an atom - for this reason, such electron ...


Adjust slider to filter visible comments by rank

Display comments: newest first

not rated yet Jun 06, 2014 a criminal I then buy myself an original. Burn it (at below the temperature that the metal would melt) and introduce what's left into my manifacturing pipeline - heavily diluted, of course.

Voila: I have now authenticated a million of my own products for the price of one original without needing to know what the barcode is (at the right mixture ratio, too).

Or does this somehow also test for particle density?
not rated yet Jun 06, 2014
How much would it cost for a company to incorporate it into the manufacturing process? If it is in the raw material then how would that prevent that raw material from finding its way into counterfeit goods?
It might be useful for preventing counterfiet goods where the source of raw material is strictly controlled like paper and or plastic stock for money.
5 / 5 (1) Jun 06, 2014 a criminal I then buy myself an original. Burn it (at below the temperature that the metal would melt) and introduce what's left into my manifacturing pipeline - heavily diluted, of course.
Of course, a smart and cost-conscious manufacturer would have heavily diluted the nanoparticles in the original product to start with -- including them at just enough of a concentration to allow for detectability...

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.