Muscle-Inspired Self-Healing Hydrogels for Strain and Temperature Sensor

TLDR

Self‑healing hydrogel bioelectronics are attractive for their tissue‑like compliance and biocompatibility, yet practical sensors are hampered by limited stretchability, sensitivity, brittleness at subzero temperatures, and single‑mode sensing. The authors propose a muscle‑inspired, self‑healing hydrogel sensor that is thermally tolerant and dual‑sensory, achieving a 90.8 % healing efficiency, a gauge factor of 18.28 over a 268.9 % strain range, a 5 % strain detection limit, and a thermosensitivity of –0.016 °C⁻¹ with 2.7 °C resolution. By incorporating a glycerol/water binary solvent, the hydrogel suppresses ice crystallization, retains water, and forms highly dynamic bonds, enabling subzero self‑healing, high water retention, and durable adhesion. The resulting device supports a flexible touch keyboard for signature identification and a “fever indicator” for detecting forehead temperature.

Abstract

Recently, self-healing hydrogel bioelectronic devices have raised enormous interest for their tissue-like mechanical compliance, desirable biocompatibility, and tunable adhesiveness on bioartificial organs. However, the practical applications of these hydrogel-based sensors are generally limited by their poor fulfillment of stretchability and sensitivity, brittleness under subzero temperature, and single sensory function. Inspired by the fiber-reinforced microstructures and mechano-transduction systems of human muscles, a self-healing (90.8%), long-lasting thermal tolerant and dual-sensory hydrogel-based sensor is proposed, with high gauge factor (18.28) within broad strain range (268.9%), low limit of detection (5% strain), satisfactory thermosensation (-0.016 °C-1), and highly discernible temperature resolution (2.7 °C). Especially by introducing a glycerol/water binary solvent system, desirable subzero-temperature self-healing performance, high water-retaining, and durable adhesion feature can be achieved, resulting from the ice crystallization inhibition and highly dynamic bonding. On account of the advantageous mechanoreception and thermosensitive capacities, a flexible touch keyboard for signature identification and a "fever indicator" for human forehead's temperature detection can be realized by this hydrogel bioelectronic device.