While hydrogels enable a variety of applications in wearable sensors and electronic skins, they are susceptible to fatigue fracture during cyclic deformations owing to their inefficient fatigue resistance. Herein, acrylated β-cyclodextrin with bile acid is self-assembled into a polymerizable pseudorotaxane via precise host-guest recognition, which is photopolymerized with acrylamide to obtain conductive polymerizable rotaxane hydrogels (PR-Gel). The topological networks of PR-Gel enable all desirable properties in this system due to the large conformational freedom of the mobile junctions, including the excellent stretchability along with superior fatigue resistance. PR-Gel based strain sensor can sensitively detect and distinguish large body motions and subtle muscle movements. The three-dimensional printing fabricated sensors of PR-Gel exhibit high resolution and altitude complexity, and real-time human electrocardiogram signals are detected with high repeating stability. PR-Gel can self-heal in air, and has highly repeatable adhesion to human skin, demonstrating its great potential in wearable sensors.
Poly(l‐glutamic acid) (PLGA), a polypeptide prepared by bacteria fermentation, has broad applications in tissue engineering. A natural host–guest pair of β‐cyclodextrin (β‐CD) and bile acid molecules are attached covalently onto the PLGA backbones separately, and host–guest crosslinked self‐healing hydrogels can be easily formed by mixing these polymer solutions. Inspired by the adhesives of mussel foot proteins, a dopamine methyl acrylamide derivative is introduced into this system to prepare a PLGA‐based dual‐network hydrogel in situ through the combination of host–guest crosslinking and the photo‐crosslinking of the dopamine derivative. The mechanical properties of the hydrogels can be tuned by altering the molar ratios of β‐CD and bile acid as well as the content of dopamine methyl acrylamide derivative. The dynamic inclusion complexation of β‐CD and bile acid allows the hydrogel to self‐heal rapidly under ambient atmosphere and their mechanical properties can recover to original levels within 1 min as evidenced in rheological results. The dual‐network hydrogels exhibit stronger adhesion behavior to pig skin than the host–guest crosslinked hydrogels in vitro. The adhesion of the dual‐network hydrogels to rat whole cortical incision has promoted faster wound healing and tissue regeneration than that in sutured treatments in vivo.
Development of self-healing hydrogels with the adjustable fluorescence still remains a challenge, due to the water-induced aggregation-caused quenching nature of the traditional organic luminogens. In this work, a fluorescent self-healing...
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