Mechanically-compliant Bioelectronic Interfaces through Fatigue-resistant Conducting Polymer Hydrogel Coating.

Because of their distinct electrochemical and mechanical properties, conducting polymer hydrogels have been widely exploited as soft, wet, and conducting coatings for conventional metallic electrodes, providing mechanically compliant interfaces and mitigating foreign body responses. However, the long-term viability of these hydrogel coatings has been hindered by concerns regarding fatigue crack propagation and/or delamination caused by repetitive volumetric expansion/shrinkage during long-term electrical interfacing. Here, we report a general yet reliable approach to achieving a fatigue-resistant conducting polymer hydrogel coating on conventional metallic bioelectrodes by engineering nanocrystalline domains at the interface between the hydrogel and metallic substrates. We demonstrate the efficacy of this robust, biocompatible, and fatigue-resistant conducting hydrogel coating in cardiac pacing, showcasing its ability to effectively reduce the pacing threshold voltage and enhance the long-term reliability of electric stimulation. Our findings highlight the potential of our approach as a promising design and fabrication strategy for the next generation of seamless bioelectronic interfaces. This article is protected by copyright. All rights reserved.