Transparent Multifunctional Wearable Strain Sensor With Self-Healing and Antibacterial Capabilities for Human Motion...

Wearable strain sensors are highly desirable due to their increasing applications in smart electronic skins and healthcare monitoring systems. Nevertheless, simultaneously integrating high stretchability, sensing linearity, stable operation under sub-zero temperatures, and long-term storage for conductive films remains a formidable challenge. Herein, a dual-network polyvinyl alcohol (PVA)-based high-performance strain sensor that overcomes these limitations through an innovative materials design is reported. The network is constructed via synergistic cross-linking of PVA with tannic acid (TA) and glutaraldehyde (GA), followed by the incorporation of choline acetate ionic liquid (IL) to enhance the multifunctionality of the sensor (denoted as PTGIL). The PTGIL sensor exhibits a compelling combination of properties, such as exceptional mechanical robustness (strength ≈20 MPa; elongation at break ≈900%), room-temperature self-healing capability, and transparency (≈88% transmittance at 550 nm). Critically, it demonstrates stable sensing performance even at sub-zero temperatures and preserves functionality after long-term ambient storage. The biocompatibility with human dermal fibroblasts and the antimicrobial activities against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) confirm its safety and further support long-term skin contact applications. Beyond conventional motion monitoring, the multifunctionality of the PTGIL sensor may help bridge soft biomechanics and healthcare applications such as rehabilitation tracking following joint ligament reconstruction and intraoperative motion-outcome correlation analysis.