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.

No abstract

No abstract

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.

advantages of high catalytic activity, good stability, low cost, and other unique properties of nanomaterials. So far, a variety of nanoscale materials, such as fullerene derivatives, [5,6] gold nanoparticles, [7,8] rare earth nanoparticles, [9] and ferromagnetic nanoparticles, [10] have been discovered to possess unique enzyme-mimic catalytic activities. These nanozymes have already found wide applications in numerous fields, including biosensing, disease therapy, detoxification, and pollutant removal. [3] Perovskite nanocrystals (NCs) have emerged as potential candidates for the next-generation lighting systems, because of their extraordinary physiochemical properties, such as, simple synthesis, high fluorescence quantum yield, narrow emission bandwidth, and wide and tunable emission covering the full visible range. [11][12][13] In consideration of their unique advantages and huge success in optoelectronics, [14,15] one may envision perovskite NCs would also hold great potential for biological applications akin to their quantum dots counterparts. However, the application of perovskite NCs in biological fields is largely lagged, because they are limited by some longstanding concerns, including extremely low stability in aqueous CsPbX 3 perovskite nanocrystals (NCs), with excellent optical properties, have drawn considerable attention in recent years. However, they also suffer from inherent vulnerability and hydrolysis, causing the new understanding or new applications to be difficultly explored. Herein, for the first time, it is discovered that the phospholipid membrane (PM)-coated CsPbX 3 NCs have intrinsic biocatalytic activity. Different from other peroxidase-like nanozymes relying on extra chromogenic reagents, the PM-CsPbX 3 NCs can be used as a self-reporting nanoprobe, allowing an "add-to-answer" detection model. Notably, the fluorescence of PM-CsPbX 3 NCs can be rapidly quenched by adding H 2 O 2 and then be restored by removing excess H 2 O 2 . Initiated from this unexpected observation, the PM-CsPbX 3 NCs can be explored to prepare multi-color bioinks and metabolite-responsive paper analytical devices, demonstrating the great potential of CsPbX 3 NCs in bioanalysis. This is the first report on the discovery of nanozyme-like property of all-inorganic CsPbX 3 perovskite NCs, which adds another piece to the nanozyme puzzle and opens new avenues for in vitro disease diagnostics.The ORCID identification number(s) for the author(s) of this article can be found under

No abstract

To meet critical requirements on flexible electronic devices, multifunctionalized flexible sensors with excellent electromechanical performance and temperature perception are required. Herein, lignin-reinforced thermoresponsive poly(ionic liquid) hydrogel is prepared through an ultrasound-assisted synthesized method. Benefitting from the electrostatic interaction between lignin and ionic liquid, the hydrogel displays high stretchability (over 1425%), excellent toughness (over 132 kPa), and impressive stress loading-unloading cyclic stability. The hydrogel strain sensor presents excellent electromechanical performance with a high gauge factor (1.37) and rapid response rate (198 ms), which lays the foundation for human body movement detection and smart input. Moreover, owing to the thermal-sensitive feature of poly(ionic liquid), the as-prepared hydrogel displays remarkable thermal response sensitivity (0.217°C-1) in body temperature range and low limit of detection, which can be applied as a body shell temperature indicator. Particularly, the hydrogel can detect dual stimuli of strain and temperature and identify each signal individually, showing the specific application in human-machine interaction and artificial intelligence. By integrating the hydrogel strain sensor into a wireless sensation system, remote motion capture and gesture identification is realized in real-time.