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.

Electronic skin is driving the next generation of cutting-edge wearable electronic products due to its good wearability and high accuracy of information acquisition. However, it remains a challenge to fulfill the requirements on detecting full-range human activities with existing flexible strain sensors. Herein, highly stretchable, sensitive, and multifunctional flexible strain sensors based on MXene- (Ti3C2Tx-) composited poly(vinyl alcohol)/polyvinyl pyrrolidone double-network hydrogels were prepared. The uniformly distributed hydrophilic MXene nanosheets formed a three-dimensional conductive network throughout the hydrogel, endowing the flexible sensor with high sensitivity. The strong interaction between the double-network hydrogel matrix and MXene greatly improved the mechanical properties of the hydrogels. The resulting nanocomposited hydrogels featured great tensile performance (2400%), toughness, and resilience. Particularly, the as-prepared flexible pressure sensor revealed ultrahigh sensitivity (10.75 kPa-1) with a wide response range (0-61.5 kPa), fast response (33.5 ms), and low limit of detection (0.87 Pa). Moreover, the hydrogel-based flexible sensors, with high sensitivity and durability, could be employed to monitor full-range human motions and assembled into some aligned devices for subtle pressure detection, providing enormous potential in facial expression and phonation recognition, handwriting verification, healthy diagnosis, and wearable electronics.

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Stretchable and biocompatible flexible electronic devices are essential to meet the increasing demands of complex and multifunctional personal healthcare systems. To detect various external stimuli, noninvasively epidermal sensors with reliable and sustainable performances are desirable. Herein, ultrastretchable, self‐healable, and wearable epidermal sensors based on ultralong Ag nanowires (AgNWs) composited binary‐networked hydrogels are fabricated. The flexible hydrogel sensors can monitor dynamic strains in a wide range (4–3000%), realize high healing efficiency (94.3%) and strong adhesiveness, which is attributed to the strong covalent bond and reversible physical interaction structured binary‐network. The ultralong AgNWs network remains in direct contact under strain, ensures a rapid response to external stimuli. The strong interactions between polymer matrix and the nanowires endow the hydrogel sensors excellent sensitivity (gauge factor of 4.59) within a wide sensing range (0–850%). The cycling stability of the hydrogel sensors is further improved by the composition of AgNWs, presenting negligible degradation both on tension and compression. Based on the advantageous performances, the flexible stain sensors can differentiate complicated human motions and realize phonation recognition precisely, showing promising application in next‐generation wearable epidermal sensors with ultrabroad working range and high sensitivity.