Engineers from MIT managed to design a an electronic skin that works without conventional chips or batteries. The new device looks like a band-aid or adhesive tape, and thanks to the piezoelectric properties of the gallium nitride layer it uses, it is able to wirelessly transmit signals related to pulse, sweat and other signals of human biology.
When we dive into the details of this electronic skin, it is a sensor implemented in a flexible semiconductor film which conforms to the skin like adhesive tape. At the heart of the sensor is an ultra-thin film of high-quality gallium nitride, a material known for its piezoelectric properties, which allow it to generate an electrical signal in response to mechanical stress and mechanically vibrate in response to an electrical impulse. . The researchers used gallium nitride because they discovered that its bidirectional piezoelectric properties open the door to simultaneous sensing and wireless communication.
A team of researchers managed to produce pure single-crystal samples of gallium nitride, which were combined with a conductive layer of gold to enhance any incoming or outgoing electrical signals. Plus they showed it the device is sensitive enough to vibrate in response to things like heartbeat and sweat. These vibrations of the material generate a signal that can be read by a nearby receiver.performing the process without the need for conventional chips or batteries in the electronic skin.
During the tests, electronic skin was placed on the wrists and necks of several volunteers, and a simple antenna was used at close range to wirelessly record the frequency of the device, which was able to detect and transmit changes in surface acoustic waves. that they corresponded to the heart rate.
To go further, the device was combined with a thin ion detection membrane, a material that selectively attracts a target ion, in the case of the sodium study. With this improvement, the electronic skin was able to detect and transmit changing sodium levels when a volunteer held a heating pad and began to sweat.
Jun Min Suh, co-author of the study that made the electronic skin possible, said they showed sodium as a test, so if it’s “alters the detection membrane, it can detect any objective biomarker such as glucose or cortisol related to stress levels. It is a very versatile platform“.
For his part, Jeehwan Kim, the author of the study, emphasized that “chips require a lot of power, but our device could make the system very light without having power-hungry chips. You can put it on your body like a bandage, and together with a wireless reader on a mobile phone, it can wirelessly monitor your pulse, sweat and other biological signals.“.
Even if not everyone uses them, wearable devices are a market that has not stopped growing, so it is no longer strange to see people with smartwatches capable of offering information about some biological signals. The electronic skin developed by MIT engineers goes a step further by eliminating complex components that require a lot of power, and therefore batteries, to operate.
