Ultra-thin temperature sensor is biodegradable and biocompatible

Engineers have developed biocompatible microsensors that can be attached to food to measure temperature and check freshness.

Microsensors are already being used for many everyday applications, and are being integrated into RFID chips for innovative uses such as tracking luggage or stopping bike theft. However, as the sensors usually contain heavy metals, which are harmful to human health, they cannot currently be used for applications that involve food or internal medicine. Recently, however, engineers at ETH Zurich University have developed biodegradable temperature microsensors which may one day be safe enough to be used with food.

The new microsensors are created by enclosing a superfine electrical filament made of magnesium, silicon dioxide and nitride inside a compostable polymer made from corn and potato starch – all materials that are safe for human ingestion. The sensor is thinner than a human hair and weighs just a fraction of a milligram. Researchers connected the sensor to an external micro-battery using ultra-thin, biodegradable zinc cables. In addition to a microprocessor, the sensor contains a transmitter capable of sending temperature data via Bluetooth. This makes it possible to monitor the temperature of a product over a range of 10 to 20 meters (30-60 feet).

Although producing the sensors is currently an expensive and time-consuming process, lead researcher Giovanni Salvatore believes that it will soon be possible to mass produce the sensors. He envisions them being used to incorporate food products into the Internet of Things; for example, by fitting individual fish with sensors to monitor temperature fluctuations during shipment. Although more research is required before the biodegradable sensors are deemed safe for human use, and the team is still searching for a biocompatible energy source to power the sensors, Salvatore predicts that within ten years they will be part of our everyday lives. What uses will there be for a tiny, biocompatible sensor?