Mussel-inspired PAM–PDA/Ga3+ hydrogels with antibacterial, adhesive and self-healable properties for wearable strain sensors

Abstract

Conductive wearable hydrogel sensors have attracted extensive research attention, yet integrating multiple functions into a single hydrogel system remains a critical challenge. In this study, we developed a multifunctional polyacrylamide–polydopamine/gallium(III) (PAM–PDA/Ga³⁺) hydrogel with antibacterial, adhesive, and self-healing properties for wearable strain sensing applications. This hydrogel was fabricated by Ga³⁺-accelerated oxidative polymerization of dopamine (DA) to form polydopamine/gallium(III) nanoparticles (PDA/Ga³⁺ NPs) via coordination interaction, along with free radical polymerization of the acrylamide (AM) monomer. The PAM–PDA/Ga³⁺ hydrogel exhibits excellent mechanical properties and self-healing ability due to multiple covalent and non-covalent interactions. Abundant catechol groups in PDA impart remarkable adhesive capability, while incorporated Ga³⁺ ions confer broad-spectrum antibacterial properties against Staphylococcus aureus and Escherichia coli. As a wearable strain sensor, the self-healing, adhesive and antibacterial hydrogel demonstrates robust performance in detecting diverse mechanical deformations and human motions, highlighting its potential for next-generation wearable electronics, soft robotics, and electronic skin technologies.