Biodegradable label to protect sensitive goods

(CONNECT) Researchers from the Swiss Federal Laboratories for Materials Science and Technology (Empa) in Dübendorf, the Swiss Federal Institute of Technology Lausanne (EPFL) and the Centre Suisse d'Electronique et de Microtechnique (CSEM) have jointly developed new smart sensor labels. According to a press release, these stickers are designed to detect and transmit the temperature and humidity of the surfaces to which they are applied in real time.

The researchers developed the new labels in a four-year collaboration. The special thing about these stickers is that they are completely biodegradable and do not require silicon-based chips. They contain printed strips of conductive materials. The capacitive elements inside react to electromagnetic fields, such as those emitted by a label reader. Depending on the different temperature or humidity, they react electrically differently, so that these values can be read in reverse. This makes it possible to track the cold chains of food and medicines, for example.

As a special feature, one element of the tracks melts irreversibly at temperatures above 25 degrees Celsius, indicating that the product has been exposed to too high a temperature. "If we are talking about vaccinations, for example, this could mean that the delivery may no longer be used, or that the best-before date is invalid," Gustav Nyström, head of the Dübendorf-based Empa Cellulose and Wood Materials laboratory and of the study, is quoted as saying in the press release. This temperature threshold could also be changed using different materials. The study was recently published in the journal Nature Communications. ce/ww