Together with a colleague from Technical University Delft, Holland, researchers from Utrecht University have developed an invisible and biodegradable mini label to check the safety of food and medication. A unique proof that the product is from the manufacturer printed on the packaging. A built-in sensor emits a signal if it is insufficiently cooled during transport or storage, another if there is a risk of bacterial spoilage.
Expensive medication that appears to be bogus, or foods that are spoiled because no refrigerated vehicles have been used for long journeys. How does the seller or consumer know that the product delivered is genuine and meets the quality requirements? Dr. Burak Eral and Dr. Ivan Rehor from the group of Professor Willem Kegel of Utrecht University came up with the idea of a product label that is so small that it can be applied unseen on the pill or in the foodstuff. The label should also be easy to scan, so that the seller or consumer can test the product's suitability. The idea combines a microfluid technique co-developed by Burak Eral at the Massachusetts Institute of Technology, and advanced bio-degradable hydrogels developed by Dr. Tina Vermonden and Prof. Wim Hennink of the Department of Pharmaceutical Sciences at Utrecht University.
The label measures only 0.1 x 0.03 x 0.025 mm and is hardly visible to the naked eye. The label is marked with a code of 32 binary digits, allowing 4.3 billion unique codes. The advanced technological knowledge that this requires makes it difficult for criminals to imitate such a label. In addition, the label is placed on or inside the product itself, rather than on the packaging, making tampering more difficult.
The label contains two miniature sensors. One discolours when the acidity of the product changes, which is often caused by bacterial growth. On the other side, the bottom of the label breaks off if the temperature rises too high. The code and sensors must be read out with a microscope. An attachment microscope for the smartphone is being developed for large-scale use.
The research has been published in the scientific journal Small.