Biocompatible electronics for health monitoring vanish when no longer needed

An interdisciplinary team of researchers from Northwestern University, the University of Illinois at Urbana-Champaign and Tufts University are the first to demonstrate ''transient electronics'' -- which are electronics that gradually disappear on a specified schedule, whether it be a few days or six months.

These kinds of electronics could have applications in medicine, pharmaceuticals, environmental monitors and the military, among other uses.

Conventional electronics are made to last indefinitely. Transient electronics, on the other hand, offer the opposite behaviour. They physically vanish over time in a well-controlled manner and at a prescribed time, dissolving when they react with water. A magnesium oxide encapsulation layer and silk overcoat envelops the electronics, and the thickness determines how long the system will take to disappear into its environment.

''These electronics are there when you need them, and after they've served their purpose they disappear,'' said Yonggang Huang, who led the Northwestern portion of the research focused on theory, design and modeling. ''This is a completely new concept.''

The novel technology opens up important possibilities. Transient electronics could be useful as medical devices implanted inside the human body to monitor such things as temperature or brain, heart and muscle tissue activity, to apply thermal therapy or to deliver drugs. When no longer needed, the electronics would be fully absorbed by the body with no adverse effects. Implantable electronics are not commonly used in medicine because of concern about the long-term effects.

Such a system also could be used as environmental monitors placed on buildings, roadways or military equipment to detect temperature change or structural deformation. The device would dissolve when exposed to water, eliminating the need for it to be recovered at a future date.