Mechanically‐Compliant Bioelectronic Interfaces through Fatigue‐Resistant Conducting Polymer Hydrogel Coating

Abstract

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 is hindered by concerns regarding fatigue crack propagation and/or delamination caused by repetitive volumetric expansion/shrinkage during long‐term electrical interfacing. This study reports 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. It demonstrates 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. This study findings highlight the potential of its approach as a promising design and fabrication strategy for the next generation of seamless bioelectronic interfaces.

The latest research progress of conductive hydrogels in the field of electrophysiological signal acquisition

“…However, conventional hydrogel monomers are usually not conductive and cannot respond to external stimuli, limiting their development in the field of electrophysiological signal acquisition. Conductive hydrogels with conductive properties can be prepared by adding materials such as conductive polymers, [22][23][24] conductive nanomaterials, 25,26 and free ions [27][28][29] to hydrogels, and adjusting the addition ratio of these materials and changing the hydrogel network to a gradient structure [30][31][32][33] can effectively regulate their conductivity. In addition, excellent mechanical properties, 34 anti-freezing properties, 35,36 selfadhesive properties, 37 and self-healing properties [38][39][40] can be achieved through the rational design of conductive hydrogels, which makes the conductive hydrogels have long-term stability and reusability, good adaptability in harsh environments, and accuracy of signal acquisition.…”

Strong, Antifatigue, and Ionically Conductive Organogels for High-Performance Strain Sensors

“…A hydrogel is a flexible and soft material containing a cross-linked polymeric network in a large quantity of water, and has shown wide applications in biomaterials and bioelectronics because of their intriguing properties such as biocompatibility, adaptability and versatility. − However, high water content and nonuniform network lead to their weak mechanical properties, and hydrogels also possess poor freezing resistance. , Furthermore, due to continuous water evaporation, hydrogels are easily dried in air, causing extreme instability in mechanical and electrical performance and hence severely limiting their practical applications. − …”