Rapid preparation of lignin sulfonate eutectic hydrogel as wearable sensors for deep-learning-assisted cervical spine monitoring

Conductive hydrogel-based wearable flexible electronics are of growing interest for smart health monitoring, data transmission, and human-machine interfaces. However, achieving multifunctional flexible electronics with lignin-derived, long-term adhesion, self-healing, wide-temperature threshold stability and embedded therapeutics remain unresolved bottleneck. Herein, a novel lignin sulfonate@silver eutectic hydrogel (LS@Ag-GA-DES) was synthesized via a one-step ultrafast free radical polymerization completed within 20 s. The eutectic hydrogel exhibited remarkable stretchability (1470%), strong skin adhesion (9.11 kPa), high ionic conductivity (0.57 S m −1 ), high gauge factor (15.22), along with excellent self-healing capabilities. DES endowed eutectic hydrogel with high sensitivity, rapid response (75 ms) and recovery times (84 ms), excellent wide-temperature adaptability (−40 °C to 60 °C) and long-term stable sensing performance. This eutectic hydrogel not only enabled real-time detection of subtle muscle strains and joint movements, but also adapted to a nine-grid coded information transmission interface for non-verbal fast communication (about 3 s per letter) in patients with hearing or speech impairments. Integrating AI, electronic communication and photothermal conversion module, the closed-loop management of cervical spine “monitoring-photothermal therapy-rehabilitation assessment” and abnormal posture alarm system has been achieved for the first time, suggesting the promising potential of lignin-derived eutectic hydrogel for applications in smart healthcare and information transmission.