Web Exclusive

Researchers Create Biodegradable Wearable Sensors

Instead of tossing your old tech in the trash or stashing it in a junk drawer when it’s time to upgrade,  what if you could just drop your device into a bowl of, say, vinegar and let it slowly dissolve? Thanks to a team of researchers at Stanford University, this scenario could be the future of personal electronics. And a good thing too, with 50 million metric tons of e-waste projected for 2018.

Engineer Zhenan Bao and her team have developed one of the lightest, thinnest electronic devices ever made, creating a biodegradable semiconductor synthesized from a molecule found in tattoo ink. They also created extra-thin film made from plant fibers, using it as a base to embed electrodes made of aluminum and iron. The whole thing melts away after 30 days in bath of acid as weak as vinegar. The results were published earlier this month in journal Proceedings of the National Academy of Science.

A newly developed flexible, biodegradable semiconductor developed by Stanford engineers shown on a human hair. (Image credit: Bao lab)

Bao believes the substance could be used in everything from wearable electronics to environmental surveys. “We envision these soft patches that are very thin and comfortable to the skin that can measure blood pressure, glucose value, sweat content,” Bao said in a story from Stanford’s news service. The patches could be worn for up to a week, the data downloaded and the used patch discarded. The degradable electronics could even be implanted into the human body without harm, though Bao notes more studies would need to be done to insure the viability of such implants.

The researchers are excited about how their biodegradable device could make electronics more sustainable. “We currently have computers and cell phones, and we generate millions and billions of cell phones, and it’s hard to decompose,” said Ting Lei, lead author of the research and postdoctoral fellow at Stanford. “We hope we can develop some materials that can be decomposed so there is less waste.”

The flexible semiconductor can adhere to smooth or rough surfaces and biodegrade to nontoxic products. (Image credit: Bao lab)