Researchers in the US have found a way to produce silicon devices that degrade, opening the door to biodegradable electronics and medical implants that can be absorbed safely in the body. John Rogers and colleagues at the University of Illinois at Urbana-Champaign, Tufts University and Northwestern University, have developed a new type of technology that they call "transient electronics". Based on earlier work with ultrathin sheets, the new devices dissolve in a few days – for example, in biological fluids.

Silicon hydrolyses in the body at a rate of about 1 nm a day. So, working from this understanding, Rogers and his co-workers have built devices out of 100-nm-thick silicon, using magnesium for conductors, magnesium or silicon oxide for insulators and silk as a substrate. Three weeks after implanting these in mice, the team’s devices leave only residues of silk – with the silk taking a little longer to break down.