Microsensors that make food talk

 

The ritual of going to the market and checking whether the fish is fresh by means of details such as the color of the eyes or the gills could have a much more scientific competitor. Perhaps in a few years it will be enough for us to take out our mobile phone −if the mobile phone exists as we know it− to receive all the information about the degree of freshness of the various foods. And not only if a sea bass is freshly caught, but if the cold chain has been broken at some point since it was caught. The technology to make this a reality would be based on microsensors developed by a team of Swiss scientists.

Researchers at ETH Zurich, a veteran university innovation center founded in 1855, have developed a prototype microsensor that, with a small size of 16 micrometers between 5 and 10 times smaller than a human hair, can be safely incorporated into food to health. The key is in its biodegradable and biocompatible composition. Starting from an electrical filament composed of magnesium and silicon dioxide and nitride, which in turn is encapsulated in a compostable polymer of potato starch and corn starch, the team led by Giovanni Salvatore has developed a technology that dissolves without leaving a trace in the period of days. However, during its shelf life it may revolutionize the way we process, transport and distribute food.

Salvatore, who has published the article in the journal Advanced Functional Materials in collaboration with a group of researchers, gives the example of transporting fish. The new microsensors could be used to check that the fish brought from Japan to Europe has maintained the right temperature throughout the journey. Upon arrival at their destination, the microsensors would wirelessly issue a kind of logbook about cold conditions. Then, upon consuming the fish, the sensors would dissolve without a trace. With the current thickness and size, they remain operational for a whole day, although their autonomy could be increased by changing the thickness of the polymer. Another advantage of this technology is that the sensors can be bent or stretched without losing their functionality.

Currently, a micro-battery connected by ultra-thin, biodegradable cables is used as a power source. The system has a microprocessor that transmits all temperature data via Bluetooth. However, at ETH they are already working on an integrated and biodegradable energy source that will make it possible to dispense with the aforementioned external unit in the near future.