Purdue scientists detail edible security tags for medicines

A team of researchers from Purdue University have developed edible security tags that can be embedded into medicines as an on-dose method of detecting counterfeits.

The approach is based on a flexible tag or ‘physical unclonable function’ (PUF) – comprised of a thin, transparent film made of silk proteins and fluorescent proteins genetically fused together. It forms form a unique, random pattern which isn’t visible to the naked eye and can be attached to the flat or curved surfaces of pills, tablets, or capsules.

PUFs have the ability to generate a different response each time that they are stimulated, rendering them unpredictable and extremely difficult to duplicate, says Purdue. Even the manufacturer wouldn’t be able to re-create an identical PUF tag.

Using a smartphone app under LED light, patients can verify whether their medicine is genuine right before they take it, whilst also getting pertinent information such as dosing frequency and side effects according to Young Kim, associate professor at the Weldon School of Biomedical Engineering at Purdue.

Behind the tag is a digitised, encrypted key – referenced in a database – that the team says can rule out any duplication, even if that were physically possible.

“After a single on-dose authentication by the end user, the cryptographic key can be permanently deleted in the secure server,” write the researchers in the paper, which is published in the journal Nature Communications.

The researchers are currently converting this process to a smartphone app for both pharmacies and consumers. A new company – called CryptoMED – has been set up to develop the technology further.

Currently, the PUF tags work for at least a two-month period without the proteins degrading, so additional work also needs to be done to ensure that a tag will last throughout a medicine’s shelf life, and that it doesn’t affect a medicine’s key ingredients or potency.