In Situ Fabrication of Benzoquinone Crystal Layer on the Surface of Nest-Structural Ionohydrogel for Flexible "All-in-One" Supercapattery.

Flexible energy-storage devices lay the foundation for a convenient, advanced, fossil fuel-free society. However, the fabrication of flexible energy-storage devices remains a tremendous challenge due to the intrinsic dissimilarities between electrode and electrolyte. In this study, a strategy is proposed for fabricating a flexible electrode and electrolyte entirely inside a matrix. First, a nest-structural and redox-active ionohydrogel with excellent stretchability (up to 3000%) and conductivity (167.9 mS cm-1 ) is designed using a hydrated ionic liquid (HIL) solvent and chemical foaming strategy. The nest-structure ionohydrogel provides sufficient "highways" and "service area", and the cation in HIL facilitates the reaction, transportation, and deposition of benzoquinone. Subsequently, in situ, a novel benzoquinone crystal-gel interface (CGI) is in situ fabricated on the surface of the ionohydrogel through electrochemical deposition of benzoquinone. Thus, an integrated CGI-gel platform is successfully achieved with a middle body as an electrolyte and the surficial redox-active CGI membrane for electrochemical energy conversion and storage. Based on the CGI-gel platform, an extreme simple and effective "stick-to-use" strategy is proposed for constructing flexible energy-storage devices and then a series of flexible supercapatteries are fabricated with high stretchability and capacitance (5222.1 mF cm-2 at 600% strain), low self-discharge and interfacial resistance and a wearable, self-power and intelligent display.

GOx/Hb Cascade Oxidized Crosslinking of Silk Fibroin for Tissue-Responsive Wound Repair.

Promising wound dressings can achieve rapid soft-tissue filling while refactoring the biochemical and biophysical microenvironment to recruit endogenous cells, facilitating tissue healing, integration, and regeneration. In this study, a tissue biomolecule-responsive hydrogel matrix, employing natural silk fibroin (SF) as a functional biopolymer and haemoglobin (Hb) as a peroxidase-like biocatalyst, was fabricated through cascade enzymatic crosslinking. The hydrogels possessed mechanical tunability and displayed adjustable gelation times. A tyrosine unit on SF stabilised the structure of Hb during the cascade oxidation process; thus, the immobilized Hb in SF hydrogels exhibited higher biocatalytic efficiency than the free enzyme system, which provided a continuously antioxidative system. The regulation of the dual enzyme ratio endowed the hydrogels with favourable biocompatibility, biodegradability, and adhesion strength. These multifunctional hydrogels provided a three-dimensional porous extracellular matrix-like microenvironment for promoting cell adhesion and proliferation. A rat model with a full-thickness skin defect revealed accelerated wound regeneration via collagen deposition, re-epithelialisation and revascularisation. Enzyme-loaded hydrogels are an attractive and high-safety biofilling material with the potential for wound healing, tissue regeneration, and haemostasis.

Nanogel Multienzyme Mimics Synthesized by Biocatalytic ATRP and Metal Coordination for Bioresponsive Fluorescence Imaging.

The design of enzyme mimics from stable and nonprotein systems is especially attractive for applications in highly specific cancer diagnosis and treatment, and it has become an emerging field in recent years. Herein, metal crosslinked polymeric nanogels (MPGs) were prepared using FeII ion coordinated biocompatible acryloyl-lysine polymer brushes obtained from an enzyme-catalyzed atomic transfer radical polymerization (ATRPase) method. The monoatomic and highly dispersed Fe ions in the MPGs serve as efficient crosslinkers of the gel network, and also as active centers of multienzyme mimics of superoxide dismutase (SOD) and peroxidase (POD). The catalytic activities were compared to those of conventional Fe-based nanozymes. Studies on both cells and animals verify that efficient reactive oxygen species (ROS) responsive biofluorescence imaging can be successfully realized using the MPGs.

Dual-Enzyme Crosslinking and Post-polymerization for Printing of Polysaccharide-Polymer Hydrogel.

Polymer hydrogels are ideal bioprinting scaffolds for cell-loading and tissue engineering due to their extracellular-matrix-like structure. However, polymer hydrogels that are easily printed tend to have poor strength and fragile properties. The gradually polymerized reinforcement after hydrogel printing is a good method to solve the contradiction between conveniently printed and high mechanical strength requirement. Here, a new succinct approach has been developed to fabricate the printable composite hydrogels with tunable strength. We employed the HRP@GOx dual enzyme system to initiate the immediate crosslinking of chondroitin sulfate grafted with tyrosine and the gradual polymerization of monomers to form the composite hydrogels. The detailed two-step gelation mechanism was confirmed by the Fluorescence spectroscopy, Electron paramagnetic resonance spectroscopy and Gel permeation chromatography, respectively. The final composite hydrogel combines the merits of enzymatic crosslinking hydrogels and polymerized hydrogels to achieve adjustable mechanical strength and facile printing performance. The dual-enzyme regulated polymer composite hydrogels are the promising bioscaffolds as organoid, implanted materials, and other biomedical applications.

Strength-tunable printing of xanthan gum hydrogel via enzymatic polymerization and amide bioconjugation.

Amide bioconjugation and interfacial enzyme polymerization are designed to provide a general strategy for regulating the mechanical strength (storage modulus from 3 kPa to 100 kPa) of printable hydrogel inks.