Self-crosslinked lignin-based elastomer sensors for multifunctional sensing: A proof-of-concept study in limb rehabilitation

Precise monitoring and rehabilitation guidance of the affected limb during the perioperative period were crucial for severed limb replantation patients. However, the existing methods have obvious shortcomings in time continuity, multi-parameter perception, passive rehabilitation and feedback timeliness. Here, a self-crosslinked lignin-based elastomer sensor (AL-E) was developed without external initiators and crosslinking agents, demonstrating its potential for perioperative monitoring and rehabilitation functions. The introduction of lignin as a renewable biomaterial enhanced the renewability of elastomer and imparted the AL-E with a low Young’s modulus (92.96 kPa), high stretchability (729%), fast self-healing under UV irradiation (< 10 min), and rapid response (0.1 s). These properties suggested the potential of the AL-E for applications in identifying the risk of limb hypothermia caused by insufficient blood supply and capturing respiratory monitoring through its temperature sensitivity, while also quantifying postoperative recovery effect and controlling a robotic hand for assisted passive rehabilitation via its strain responsiveness. Furthermore, a conceptual framework for physiological monitoring and rehabilitation was established based on the AL-E, offering a potential pathway toward a full-cycle spanning intraoperative monitoring, postoperative warning, and rehabilitation guidance. Overall, this study represents a promising step toward a potential method to address the multiple demands during the perioperative phase of limb replantation.