New Anti-Counterfeiting Fluorescent Marker Developed

A team of researchers at the Max Planck Institute of Colloids and Interfaces (MPICI), in Germany, has developed a method that could make it more difficult to counterfeit products. The new and patented method makes it possible to produce unique, non-copyable, environment-friendly fluorescent patterns, quickly and at low cost.

According to the World Health Organisation (WHO), most of the counterfeit medicines in circulation are obtained through street markets and unregulated websites ¹. To combat this, medicine packaging is often marked with security features on their labelling which might contain toxic inorganic compounds. Other approaches to prevent counterfeiting use techniques to produce unclonable patterns that require tedious fabrication or complex readout methods.

In a paper published in the journal Nature Nanotechnology ², the team, from the Department of Biomolecular Systems at MPICI, presented a nanoprinting-assisted flash synthesis approach that generates fluorescent nanofilms with physical unclonable function (PUF) micropatterns, in milliseconds. This all-in-one approach yields carbon dots in solid films, directly from simple monosaccharides.

First, a thin sugar film consisting of simple monosaccharides is bombarded with a laser. In this flash synthesis, the sugar ‘caramelises’ in milliseconds, and at the same time the laser prints random ‘caramel patterns’ on a desired surface. These are unique and fluoresce in different colours when stimulated.

Junfang Zhang, first author of the study, said: ‘the exciting thing here is that you can create any pattern you want, which we have shown using the example of artificial fingerprints. The resulting micro- and nanostructures are completely random. We cannot control them; there will be no pattern’.

Group leader Dr Felix Löffler added: ‘each sugar pattern has a unique topography, and depending on the laser parameters and additives, we get unique colour gradations of red, green or blue’.

In its experiments, the team created a nanofilm library of about 2,000 nanopatterns. Two methods – fluorescence scanning and topography scanning – can be used to quickly and independently read the microstructure of these sugar patterns, which, it claimed, cannot be copied. Both methods demonstrate high uniqueness and reliability in the patterns produced.

This means that the patterns have a very high degree of randomness, which is important for their function as a copy protection system. The combination of both methods improves the protection even further. ‘In addition, with our method we can generate up to 10 to the power of 63,000 different variants on 1mm². For comparison, the number of atoms in the universe is about 10 to the power of 89,’ said Dr Löffler.