A High-Density Hydrogen Bond Locking Strategy for Constructing Anisotropic High-Strength Hydrogel-Based Meniscus Substitute.

Mimicking anisotropic features is crucial for developing artificial load-bearing soft tissues such as menisci). Here, a high-density hydrogen bond locking (HDHBL) strategy, involving preloading a poly(N-acryloylsemicarbazide) (PNASC) hydrogel with an aqueous solution containing a hydrogen bond breaking agent, followed by water exchange, to fabricate anisotropic high-strength hydrogels are proposed. During this process, multiple high-density hydrogen bonds of the PNASC network are re-established, firmly freezing oriented molecular chains, and creating a network with an anisotropic microstructure. The resulting anisotropic hydrogels exhibit superior mechanical properties: tensile strength over 9 MPa, Young's modulus exceeding 120 MPa along the orientation direction, and fatigue thresholds exceeding 1900 J m-2. These properties meet the mechanical demands for load-bearing tissue substitutes compared to other reported anti-fatigue hydrogels. This strategy enables the construction of an anisotropic meniscal scaffold composed of circumferentially oriented microfibers by preloading a digital light processing-3D printed PNASC hydrogel-based wedge-shaped construct with a resilient poly(N-acryloyl glycinamide) hydrogel. The 12-week implantation of a meniscus scaffold in rabbit knee joints after meniscectomy demonstrates a chondroprotective effect on the femoral condyle and tibial plateau, substantially ameliorating the progression of osteoarthritis. The HDHBL strategy enables the fabrication of various anisotropic polymer hydrogels, broadening their scope of application.

Boosting Photoresponse of Self-Powered InSe-Based Photoelectrochemical Photodetectors via Suppression of Interface Doping.

Two-dimensional (2D) InSe is a good candidate for high-performance photodetectors due to its good light absorption and electrical transport properties. However, 2D InSe photodetectors usually endure a large driving voltage, and 2D InSe-based heterojunction photodetectors require complex fabrication processes. Here, we demonstrate high-performance self-powered InSe-based photoelectrochemical (PEC) photodetectors using electrochemical intercalated ultrathin InSe nanosheets. The ultrathin InSe nanosheets have good crystallinity with a uniform thickness of 1.4-2.1 nm, lateral size up to 18 µm, and yield of 82%. The self-powered InSe-based PEC photodetectors show broadband photoresponse ranging from 365 to 850 nm. The photoresponse of InSe-based PEC photodetectors is boosted by suppressing p-type doping of the intercalator with annealing, which improves the electrical properties and facilitates electron transport from InSe to the electrode. The self-powered annealed InSe (A-InSe) PEC photodetectors show a high responsivity of 10.14 mA/W and fast response speed of 2/37 ms. Moreover, the self-powered PEC photodetectors have good stability under UV-NIR irradiation. Furthermore, the photoresponse can be effectively tuned by the concentration and kind of electrolyte. The facile large-scale fabrication and good photoresponse demonstrate that 2D ultrathin InSe can be applied in high-performance optoelectronic devices.

High-Performance Broadband Photoelectrochemical Photodetectors Based on Ultrathin Bi2O2S Nanosheets.

Two-dimensional (2D) bismuth oxychalcogenide (Bi2O2X, X refers to S, Se, and Te) is one type of rising semiconductor with excellent electrical transport properties, high photoresponse, and good air stability. However, the research on 2D Bi2O2S is limited. In this work, ultrathin Bi2O2S nanosheets are synthesized by a facile and eco-friendly chemical synthesis method at room temperature. The thickness and lateral sizes are 2-4 nm and 20-40 nm, respectively. The 2D ultrathin Bi2O2S nanosheets have a broad absorption spectrum from ultraviolet (UV) to near-infrared (NIR). Photoelectrochemical (PEC) photodetectors based on 2D Bi2O2S nanosheets are fabricated by a simple drop-casting method. The 2D Bi2O2S-based PEC photodetectors show excellent photodetection performance with a broad photoresponse spectrum from 365 to 850 nm, a high responsivity of 13.0 mA/W, ultrafast response times of 10/45 ms, and good long-term stability at a bias voltage of 0.6 V, which are superior to most 2D material-based PEC photodetectors. Further, the 2D Bi2O2S PEC photodetector can function as a high-performance self-powered broadband photodetector. Moreover, the photoresponse performance can be effectively tuned by the concentration and the kind of electrolyte. Our results demonstrate that 2D Bi2O2S nanosheets hold great promise for application in high-performance optoelectronic devices.

Antibacterial, antioxidant and biocompatible nanosized quercetin-PVA xerogel films for wound dressing.

Topical use of antimicrobial agents to treat wounds to inhibit bacterial invasion and facilitate wound healing is an effective strategy. In this work, an antibacterial xerogel film for potential applications in wound dressings was developed. First, a natural antibacterial agent, quercetin (Qu), was made into water-soluble quercetin-borate (QuB) nanoparticles by merging a solvent exchange method with the borate esterification reaction. QuB nanoparticles were then employed as the cross-linking agent to achieve gelation of poly(vinyl alcohol) (PVA) to obtain antimicrobial QuB-PVA composite microgels. Furthermore, QuB-PVA microgels were utilized as raw materials to produce xerogel films via an electrospray technique. The as-prepared QuB-PVA xerogel films exhibited excellent bacteriostasis, antioxidation, biocompatibility, self-healing, accelerated skin regeneration and functional restoration, and promoted skin wound healing. The QuB-PVA films significantly facilitated the in vivo healing speed of full-thickness skin wounds compared to commercial dressings. We believe that the present multifunctional QuB-PVA xerogel film is an excellent candidate for the wound dressings.

The innovative fabrication of nano-natural antimicrobial agent@polymeric microgels-TiO2 hybrid films capable of absorbing UV and antibacterial on touch screen panel.

It is significant to develop a protective film (coating) for touch screen panels with combined absorbing UV and antibacterial performances. This work developed a smart strategy to fabricate multifunctional protective films for touch screen panels. Polymeric microgels of polyquaternium-10 (PQ) and sodium alginate (SA) were firstly fabricated based on electrostatic interactions. The PQ-SA microgels solution was then cast on a glass substrate to produce PQ-SA films. Further, peroxo titanic acid as cross-linking agent was employed to cross link PQ-SA films via forming coordination bonds between polymers and Ti of peroxo titanic acid, whereafter TiO2 nanoparticles were generated in situ in PQ-SA films by hydrolyzing the peroxo titanic acid to endow PQ-SA films with excellent absorbing UV ability. Moreover, water-soluble quercetin and resveratrol nanoparticles are fabricated by incorporating solvent exchange method and borate esterification reaction and were loaded into the PQ-TiO2-SA films to give the films good antibacterial performance. The as-prepared multifunctional films not only exhibited excellent absorbing UV, filtering visible light and antibacterial properties, but also possessed good water resistance, abrasion resistance, self-healing performances and high adhesion to a glass substrate. We believe that present multifunctional film as a protective film for touch screen panels can provide protection for users.