Intrinsically Adhesive and Conductive Hydrogel Bridging the Bioelectronic-Tissue Interface for Biopotentials Recording

Abstract

Achieving high-quality biopotential signal recordings requires soft and stable interfaces between soft tissues and bioelectronic devices. Traditional bioelectronics, typically rigid and dependent on medical tape or sutures, lead to mechanical mismatches and inflammatory responses. Existing conducting polymer-based bioelectronics offer tissue-like softness but lack intrinsic adhesion, limiting their effectiveness in creating stable, conductive interfaces. Here, we present an intrinsically adhesive and conductive hydrogel with a tissue-like modulus and strong adhesion to various substrates. Adhesive catechol groups are incorporated into the conductive poly(3,4-ethylenedioxythiophene) (PEDOT) hydrogel matrix, which reduces the PEDOT size and improves dispersity to form a percolating network with excellent electrical conductivity and strain insensitivity. This hydrogel effectively bridges the bioelectronics-tissue interface, ensuring pristine signal recordings with minimal interference from bodily movements. This capability is demonstrated through comprehensive in vivo experiments, including electromyography and electrocardiography recordings on both static and dynamic human skin and electrocorticography on moving rats. This hydrogel represents a significant advancement for bioelectronic interfaces, facilitating more accurate and less intrusive medical diagnostics.

Keywords: adhesion; bioelectronic−tissue interfaces; biopotential recording; conductivity; flexible electronics; hydrogels.