Flexible and wearable sensor based on nanocomposite hydrogels has been proposed for monitoring the human large-scale, small-scale movements and several physiological signals. The nanocomposite hydrogel, prepared from graphene oxide (GO), polyvinyl alcohol (PVA) and polydopamine (PDA), exhibits excellent mechanical and electrical properties with tensile stress of 146.5 KPa, fracture strain of 2580%, fracture energy of 2390.86 KJ m−3, and the conductivity of 5 mS cm−1. In addition, it possesses other merits including good self-healing with the electrical self-healing efficiency of 98% of its original resistance within 10 s, and strong self-adhesion onto a variety of surfaces of materials. This self-adhesive, self-healing, graphene-based conductive hydrogel can further assembled as wearable sensors to accurate and real-time detect the signals of human large-scale motions (including bending and stretching fingers joints, wrists joints, elbows joints, neck joints and knees joints) and small-scale motions (including swallowing, breathing and pulsing) through fracturing and recombination of reduced graphene oxide (rGO) electrical pathways in porous structures of hydrogel networks. Furthermore, the hydrogel can also be used as self-adhesive surface electrodes to detect human electrophysiological (ECG) signals. Therefore, the hydrogel-based wearable sensor is expected to be used for long-term and continuous monitoring human body motion and detecting physiological parameters.

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The hydrogel is a preferred material for flexible wearable sensors. In practical application, it should have highefficiency mechanical toughness and self-healing performance. Besides, hydrogel requires good affinity and adhesion because of its contact with the skin. In this experiment, we made an ultra-tough hydrogel with excellent cell affinity and adhesion. We used sodium alginate (SA) and polyacrylamide (PAm) mixture as a flexible base fluid. Polydopamine reduce graphene oxide (prGO) was used as conductive nanofiller, and then PAm-prGO-SA semiinterpenetrating network hydrogel was formed through Am radical polymerization. The presence of prGO endows the hydrogels with excellent electrical conductivity. Simultaneously, some non-reduced GO forms non-covalent cross-links with PAm, SA, and Polydopamine (PDA) in the hydrogel network. The stress of PAm-prGO-SA hydrogel can reach 750 KPa, and the strain is 900%. The hydrogel, combined with its excellent electrical, mechanical properties, and biocompatibility, is expected to be applied in portable, remote, and real-time health monitoring systems.

Despite the progress in chronic wound treatment, antibacterial cutaneous scaffold with high efficiency in wound healing is still the hot spot in the field. In present study, a functionalized silk fibroin (SF) cutaneous scaffold incorporated with natural medicine usnic acid (UA) is investigated, in which UA is used as an antibacterial and wound‐healing reagent. Via electrospinning, UA–SF mixture is fabricated into UA–SF composite scaffold (USCS), which is composed of uniform nanofibers with average diameters of around 360 ± 10 nm. The interwoven nanofibers form mesh structure providing sufficient moisture permeability for scaffold. With methanol treatment, USCS presents improved mechanical properties and stability to protease XIV. In the presence of USCS, the growth rate of both Gram‐positive and Gram‐negative bacteria, including Staphylococcus aureus, Streptococci pyogenes, Escherichia coli, and Pseudomonas aeruginosa, is significantly inhibited in plate culture and suspension assays. In a cutaneous excisional mouse wound model, USCS presents a significant increase of wound closure rate, compared with pure SF scaffold and commercial dressing, Tegaderm Hydrocolloid 3M. The histological assessments further prove that USCS can enhance re‐epithelialization, vascularization, and collagen deposition in wound site to promote the wound‐healing process, which indicates the potential application of USCS in chronic wound treatment.

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