# Transparent Multifunctional Wearable Strain Sensor With Self‐Healing and Antibacterial Capabilities for Human Motion Detection

## TL;DR

A transparent strain sensor with self-healing and antibacterial properties is developed for wearable health monitoring and motion detection.

## Contribution

A dual-network PVA-based strain sensor is introduced with self-healing, antibacterial, and sub-zero performance capabilities.

## Key findings

- The PTGIL sensor shows high mechanical robustness with 20 MPa strength and 900% elongation at break.
- The sensor maintains stable performance at sub-zero temperatures and after long-term storage.
- It exhibits biocompatibility and antimicrobial activity against S. aureus and E. coli.

## Abstract

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.

A transparent dual‐network strain sensor integrates robust mechanical properties, room‐temperature self‐healing, and stable performance under sub‐zero conditions and prolonged storage. Its excellent biocompatibility and antimicrobial properties enable safe skin contact. Beyond conventional motion sensing, the sensor offers accurate motion tracking and holds strong potential for wearable health applications, such as joint rehabilitation monitoring in personalized healthcare systems.