Multifunctional carboxymethyl cellulose/polydopamine dual-network conductive hydrogels for motion detection and photothermal therapy

Flexible wearable sensors have garnered significant attention in recent years and exhibit promising application potential in the field of healthcare. Conductive hydrogels have emerged as ideal materials for the development of flexible wearable sensors due to their tunable structural properties, mechanical flexibility, and ease of processing. Nevertheless, most hydrogels are primarily engineered for detecting physiological signals, such as movement and electromyography (EMG), yet lack therapeutic functionalities. In addition, Previous reported hydrogels fabricated from synthetic polymers may retain residual small-molecule monomers, posing cytotoxicity risks. Herein, we report a multifunctional conductive hydrogel composed of carboxymethyl cellulose (CMC), polydopamine (PDA), and polypyrrole-polydopamine-MnO x nanoparticles (P-NPs), designed for concurrent motion monitoring, electromyography (EMG) signal detection, and photothermal therapy. The hydrogel was synthesized through a one-step amidation/oxidative polymerization approach, yielding an interpenetrating dual-network architecture with enhanced mechanical strength and tissue adhesion relative to single-network systems. The incorporation of P-NPs imparts high electrical conductivity, enabling real-time monitoring of physiological signals (e.g., joint movement, muscle activity), as well as effective photothermal conversion under near-infrared (NIR) irradiation. Notably, the hydrogel facilitates on-demand photothermal therapy to mitigate muscle fatigue upon detection of abnormal EMG signals, offering a strategy to prevent exercise-induced injury. Owing to its excellent biocompatibility and stability, the CMC/PDA/P-NPs hydrogel represents a promising platform for next-generation wearable devices integrating diagnostic and therapeutic functions.