Skin-interfaced self-powered pressure and strain sensors based on fish gelatin-based hydrogel for wireless wound strain and human motion detection

Biomass-based hydrogels, due to their excellent biocompatibility, can behave as wearable monitoring platforms for healthcare applications and triboelectric sensing devices. However, low tissue adhesiveness, poor stretchability, and bacterial susceptibility cause them to fail to adapt to specific joints with complex movements. Herein, we report a novel biomass-based hydrogel by integrating fish gelatin into polymer networks with in-situ formation of silver nanoparticles (denoted as FG-Ag hydrogel), which achieves great stretchability (2600%), excellent sensitivity (gauge factor = 4), and strong self-adhesion simultaneously. The FG-Ag hydrogel also features a robust antibacterial activity for Escherichia coli and Staphylococcus aureus. Benefitting from these advantages, we have developed a FG-Ag hydrogel-based wearable strain sensor for diverse human-motion detections such as elbow, knee, finger, and wrist bending. Moreover, we have demonstrated an FG-Ag hydrogel-based prototype with an integrated wireless system for real-time strain monitoring on the wound sites. The FG-Ag hydrogel could significantly reduce bacterial infection in vivo and effectively promote wound healing. Additionally, the self-powered pressure sensor and the biomechanical energy harvester also have been demonstrated by the FG-Ag hydrogel based triboelectric nanogenerator (TENG). Accordingly, such FG assistance of hydrogel-based skin-interfaced electronics could provide adequately delicate biomechanical information related to the general health, which furnishes essential technical support for cost-effective, all-green, and highly precise personalized health assessment.