Mussel-Inspired PAM-PDA/Ga3+ Hydrogels with Antibacterial, Adhesive and Self-healable Properties for Wearable Strain Sensors

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 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 endow 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.