Self-healing poly(vinyl alcohol)/carboxymethyl chitosan/astragalus polysaccharide hydrogels with bioactivity for high-performance strain sensing and human-machine interaction.

Hydrogel-based strain sensors hold great promise for wearable bioelectronics but conventional synthetic networks often lack dynamic repairability, tissue-matched mechanics, and sustainability. Here, we report a type of versatile polysaccharide-based hydrogel strain sensor (PC/APS), composed of poly(vinyl alcohol) (PVA), 4-formylphenylboronic acid (4-FPBA) grafted carboxymethyl chitosan (CMCS-PBA), and astragalus polysaccharide (APS), and designed without using any conductive nanofillers. The existence of multiple hydrogen bonds, Schiff base linkages, and borate ester bonds endowed PC/APS hydrogels with high toughness, good injectability, and rapid self-healing. In particular, the optimized PC/APS3 hydrogel demonstrated a good tensile strength of ∼25.1 kPa, a high value of cell viability (>105%), and intrinsic antibacterial activity against S. aureus (>91%) and E. coli (>87%). What's more, the PC/APS3 hydrogel exhibited a wide strain range of 0-250%, a high strain resolution of 0.1%, and a fast response time of ∼98 ms. The hydrogel sensors can not only ensure real-time monitoring of human joint motion, phonation, and facial expressions, but also achieve intuitive, multi-gesture control of the robotic hand after the integration into a wireless glove. This work highlights the potential of polysaccharide-based hydrogels for next-generation human-machine interaction, teleoperation, and rehabilitation interfaces.