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 electrophysiological 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.
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This work is supported by the NIH grants R01 HL115415, R01 HL114395 and R21 HL112278, and through the Frederick Seitz Materials Research Laboratory and Center for Microanalysis of Materials at the University of Illinois at Urbana-Champaign. We would like to thank the Micro and Nanotechnology Laboratory and the School of Chemical Sciences Machine Shop at the University of Illinois for help on the device fabrication. J.Z. acknowledges support from a Louis J. Larson Fellowship, Swiegert Fellowship, and H. C. Ting Fellowship from the University of Illinois, Urbana-Champaign. M.T. and J.V. acknowledge the support from the National Science Foundation award CCF 1422914. C.-H.C. and J.V. acknowledge the support from the Army Research Office award W911NF-14-1-0173.
The authors declare no competing financial interests.
Supplementary notes and figures. (PDF 2974 kb)
A flexible capacitively coupled sensing electronic system on a Langendorff-perfused rabbit heart model. (MP4 4793 kb)
Voltage data from all electrodes, illustrating the activation pattern of the heart during sinus rhythm. (MP4 6160 kb)
Voltage data from all electrodes, illustrating the paced activation pattern moving from the apex to the base. (MP4 5493 kb)
Voltage data from all electrodes, illustrating the activation pattern of the heart during ventricular fibrillation. (MP4 14134 kb)
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Fang, H., Yu, K., Gloschat, C. et al. Capacitively coupled arrays of multiplexed flexible silicon transistors for long-term cardiac electrophysiology. Nat Biomed Eng 1, 0038 (2017). https://doi.org/10.1038/s41551-017-0038
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