Biocompatible electronics sitting on thin, flexible substrates may enable the development of neural interfaces that take high-resolution measurements without irritating or scarring brain tissue, writes Katherine Bourzac in MIT’s Technology Review this week. Researchers in the United States are building high-performance flexible electronics from silicon and other conventional materials on substrates of biodegradable, mechanically strong silk films provided by researchers at Tufts University. An article in the journal Nature Materials describes a silk electrode device they have developed to measure electrical activity from the surface of a cat’s brain.
Doctors can put electrode arrays on the surface of the brain to pinpoint the source of epileptic seizures, continues Bourzac in her article, and patients can use those electrodes to control a computer cursor. But it’s still not safe to leave these devices in the brain over the long term. Brian Litt, professor of neurology and bioengineering at the University of Pennsylvania Medical School is working on alternatives with researchers at the University of Illinois at Urbana-Champaign, who are building flexible electronics from silicon and other conventional materials on substrates of biodegradable, mechanically strong silk films provided by researchers at Tufts University.
When it’s placed on brain tissue and wetted with saline, a silk film will shrink-wrap around the surface of the brain, bringing electrodes with it into the wrinkles of the tissue. Conventional surface electrode arrays can’t reach these crevices, which make up a large amount of the brain’s surface area. Moreover, surface electrodes won’t cause scarring, which is common with implanted devices.
“A device like this would completely open up new avenues in all of neuroscience and clinical applications,” says Gerwin Schalk, a researcher at the Wadsworth Center in Albany, NY, who is not affiliated with the silk electrode group, told Bourzac. “What I foresee is placing a silk-based device all around the brain and getting a continuous image of brain function for weeks, months, or years, at high spatial and temporal resolution.”