The hardware in electronics has been a poor fit for the software of human flesh. Rigid circuits do not flex with pliable organs, and hard edges tear soft tissue. This problem has severely limited efforts to improve devices such as artery-clearing catheters by adding computerized control and finesse. Silicon may support the entire computer industry, but it is notoriously brittle.
Yet even the most stubborn materials become flexible if you make them thin enough, says John Rogers, a materials scientist at the University of Illinois at Urbana-Champaign. He is building stretchable electronic sheets, just 10 nanometers thick, for devices that could be placed within or around organs such as the heart and do their jobs without causing harm. Rogers calls them “soft electronics.”
The circuits that Rogers builds must use high-fidelity conductors, such as silicon and gallium nitride, because they have to relay computer signals without a glitch. To get around silicon's tendency to break when bent, he has used nanoscale engineering to thin the material while maintaining its conductive ability. Shaved down to around 10 nanometers, silicon acts more like a rubber band and less like glass.
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In animals, Rogers has already successfully tested a flexible membrane, with embedded electronics, that can be wrapped around a beating heart to watch for abnormal rhythms. If tests continue to show success, he imagines adding electronic monitors to artery-opening devices such as balloon catheters so they can sense narrow sections of blood vessels. “Dumb mechanical devices could become sophisticated surgical tools,” Rogers says.
