Researchers at the University of Illinois at Urbana-Champaign, Tufts University, and others have created fully biodegradable electronics that could allow doctors to implant medical sensors or drug delivery devices that dissolve when they're no longer needed. The transient circuits, described in today's issue of Science, can be programmed to disappear after a set amount of time based on the durability of their silk-protein coating.

"You want the device to serve a useful function, but after that function is completed, you want it to simply disappear by dissolution and resorption into the body," says John Rogers, a physical chemist at the University of Illinois at Urbana-Champaign and senior author on the study.

The authors demonstrate this possibility with a resorbable device that can heat the area of a surgical cut to prevent bacterial growth. They implanted the heat-generating circuit into rats. After three weeks, the authors examined the site of the implant and found that the device had nearly completely disappeared, leaving only remnants of the silk coating, which is eliminated more slowly than the silicon and magnesium of the circuit itself.