Mussel-inspired sticky self-healing conductive hydrogels composites for physiological electrical sensing

Abstract

The development of electrodes capable of maintaining strong adhesion and conductivity in wet environments is crucial for a wide range of electronic applications. From underwater monitoring systems to biomedical devices, the limitations of conventional electrodes pose a significant challenge. Inspired by the adhesive and self-healing properties of marine mussels, this work introduces a self-healing conductive adhesive that not only adheres tenaciously to various surfaces in wet conditions but also demonstrates exceptional conductivity for reliable detection of electrophysiological signals. In this study, our biocompatible adhesive consists of a boronic ester-based polyvinyl alcohol hydrogel with polydopamine particles (PVA/Borax/PDAP). Borate ions enable rapid self-healing (within 10 seconds) by forming dynamic bonds with hydroxyl groups, while the π–π interactions of PDAPs enhance adhesion strength (121 kPa). The inclusion of saturated saline further improves both stretchability (up to ∼1000%) and conductivity (38.3 mS cm⁻¹). We successfully demonstrate the utility of this self-healing conductive adhesive in recording electrophysiological signals, including electroencephalography (EEG), electrodermal activity detection, and electrocardiograms, highlighting its potential for next-generation biomedical wearable devices.