Researchers at Tufts University (Medford, MA), together with colleagues at the University of Illinois at Urbana-Champaign, have developed miniature biocompatible electronic devices that can dissolve into their surroundings after performing for defined periods of time. The scientists have reported that they have implanted and dissolved the devices in the bodies of lab mice. Dubbed ‘transient electronics,' the silk-silicon devices could pave the way for medical implantable device that will never require surgical removal.

“These devices are the polar opposite of conventional electronics whose integrated circuits are designed for long-term physical and electronic stability,” remarks Fiorenzo Omenetto, professor of biomedical engineering at the Tufts School of Engineering and an author of a paper on the technology in Science. “Transient electronics offer robust performance comparable to current devices, but they will fully resorb into their environment at a prescribed time—ranging from minutes to years, depending on the application,” Omenetto explains.

The devices incorporate materials used in conventional integrated circuits—silicon and magnesium—but in an ultrathin form that is then encapsulated in silk protein. “While silicon may appear to be impermeable, eventually it dissolves in water,” Omenetto explains. The challenge is to make the electrical components dissolve in minutes rather than eons.

Device dissolution is further controlled by sheets of silk protein in which the electronics are supported and encapsulated. Omenetto and his Tufts colleagues have discovered how to adjust the properties of silk so that it degrades at a wide range of intervals. In the future, the researchers envision more-complex devices that could be adjustable in real time or responsive to other changes in their environment, such as chemistry, light, or pressure.