Capacitively coupled arrays of multiplexed flexible silicon transistors for long-term cardiac electrophysiology

Advanced capabilities in electrical recording are essential for the treatment of heart-rhythm diseases. The most advanced technologies use flexible integrated electronics; however, the penetration of biological fluids into the underlying electronics and any ensuing electrochemical reactions pose significant safety risks. Here, we show that an ultrathin, leakage-free, biocompatible dielectric layer can completely seal an underlying array of flexible electronics while allowing for electrophysiological measurements through capacitive coupling between tissue and the electronics, without the need for direct metal contact. The resulting current-leakage levels and operational lifetimes are, respectively, four orders of magnitude smaller and between two and three orders of magnitude longer than those of other flexible-electronics technologies. Systematic electro-physiological studies with normal, paced and arrhythmic conditions in Langendorff hearts highlight the capabilities of the capacitive-coupling approach. These advances provide realistic pathways towards the broad applicability of biocompatible, flexible electronic implants.