Engineering Electrodes with Robust Conducting Hydrogel Coating for Neural Recording and Modulation

摘要

Coating conventional metallic electrodes with conducting polymers hasenabled the essential characteristics required for bioelectronics, such asbiocompatibility, electrical conductivity, mechanical compliance, and thecapacity for structural and chemical functionalization of the bioelectrodes.However, the fragile interface between the conducting polymer and theelectrode in wet physiological environment greatly limits their utility andreliability. Here, a general yet reliable strategy to seamlessly interface conventionalelectrodes with conducting hydrogel coatings is established, featuringtissue-like modulus, highly-desirable electrochemical properties, robustinterface, and long-term reliability. Numerical modeling reveals the role oftoughening mechanism, synergy of covalent anchorage of long-chain polymers,and chemical cross-linking, in improving the long-term robustness ofthe interface. Through in vivo implantation in freely-moving mouse models, itis shown that stable electrophysiological recording can be achieved, while theconducting hydrogel–electrode interface remains robust during the long-termlow-voltage electrical stimulation. This simple yet versatile design strategyaddresses the long-standing technical challenges in functional bioelectrodeengineering, and opens up new avenues for the next-generation diagnosticbrain-machine interfaces.