The metabolism of D-serine by D-amino acid oxidase was developed to induce radical polymerization and formation of a powder-remoldable PAAM–CS hydrogel.

An adhesive composite of hypergravity induced Co3O4 nanoparticles and natural xanthan gum (XG) was prepared and applied as the anode electrode of a Li-ion battery for the first time. The Co3O4 nanoparticles were hydrothermally prepared and assembled on the water–oil interface with the assistance of hypergravity. The discharge capacity of the final nanocomposite anodes with the xanthan gum binder can reach 742.5 mA h g−1 after 50 cycles at a charge–discharge rate of 0.5 C, whereas the Co3O4 working electrode with a traditional PVDF binder only displayed a lower capacity of 219.9 mA h g−1. The addition of the XG binder can improve the electrochemical performance of the hypergravity Co3O4 anode due to its high viscosity, which can relieve the volume expansion of the Co3O4 particles during charge–discharge cycles. What's more, the XG can efficiently transfer Li-ions to the surface of the Co3O4 like polyethylene oxide (PEO) solid electrolytes.

Nanozymes merge nanotechnology with biology and provide a lower cost and higher stability options, compared to that of natural enzymes. However, nanozyme catalyzed polymerization under physiological conditions is still a big challenge due to heavy oxygen inhibition. In this study, the simple glucose oxidase system can effectively adjust oxygen concentration and generate hydrogen peroxide, which assists in the realization of nanozyme-catalyzed polymerization. The nanozyme based hydrogel is printable due to its mild preparation with gradually increased viscosity. The antibacterial performance is ascribed to the in situ generated hydroxyl radical via the reaction of the bound nanozyme and glucose.

Dynamic hydrogels were prepared via an oxidative deamination reaction catalyzed by monoamine oxidase B. Amino-containing polysaccharides (or proteins) and oxidative products (aldehydes) formed the dynamic Schiff base linkages, which endowed the hydrogel with excellent self-healing and multiresponsive properties.

A new approach has been developed to fabricate tough hybrid hydrogels by employing dual enzyme-mediated redox initiation to achieve post-self-assembly cross-linking polymerization. The resulting hydrogel combines the merits of supramolecular hydrogels with polymeric hydrogels to achieve higher mechanical strength and porous networks. Designed 3D constructs were fabricated via in situ 3D printing. The in situ immobilized GOx/HRP in Gel II exhibited superactivity compared to free enzymes, which might be attributed to the synergistic effect of co-localized GOx and HRP minimizing the distances for mass transport between the gel and the bulk solution. This mechanically strong hybrid hydrogel maintained high reusability and thermal stability as well. In addition, in situ 3D cell culture was demonstrated, thus indicating that this biodegradable hybrid hydrogel is biocompatible with cells. The subsequent 3D cell printing further indicates that the hybrid hydrogel is a promising scaffold for bio-related applications such as biocatalysis and tissue engineering.

We present a facile one-pot approach to fabricate tough TiO2-rGO-PDMAA nanocomposite hydrogel. Both synchronous polymerization of N, N-dimethylacrylamide (DMAA) monomer and reduction of graphene oxide (GO) sheets into porous hydrogel network are triggered by TiO2 nanoparticles under the UV irradiation. The reduction of GO is accompanied color changes of the hydrogel from light-brown to black. The interpenetrating double hydrogel network between PDMAA chains and rGO can be fabricated at a considerable GO content, at which the hydrogel exhibits tough mechanical strength, good swelling ratio and quick self-recovery character. Benefiting from the excellent carrier mobility and large surface area of the rGO, our hydrogel has an improved photo degradation performance for methylene blue, suggesting its potential application in the wastewater treatment.

This communication describes a new strategy to fabricate a nanogel layer around magnetic nanoparticles by surface free-radical polymerization triggered by the cascade reaction of urate oxidase and horseradish peroxidase, which showed high loading capacity, pH-responsive drug release and low cytotoxicity.

Rare earth elements are an important strategic resource, and it is urgent that the rare earth industry continue to explore and develop novel separation methods and technologies. Herein, we fabricated an efficient semi-IPN alginate-clay-poly(n-isopropylacrylamide) (NIPAm) hydrogel by a frozen polymerization method with the help of UV light irradiation, where alginate was employed as the main adsorption functional compound. The as-prepared hydrogel exhibits tough, sponge-like hierarchical macroporous and reversible temperature-responsive characteristics. The maximum adsorption capacity of La3+ is 182 mg/g for the hydrogel composition of 5.0% NIPAm, 4.0% clay, and 3.0% alginate. The Langmuir isotherm fits the data very well, and the adsorption follows the pseudo-second-kinetic equation. The trace of La3+ ions can be effectively separated from the coexisting metal ions. After six repeated adsorption–desorption cycles, no obvious deformation of the shape and or loss of adsorption capacity of the bulk hydrogel is found, but the stress level of the original hydrogel is significantly enhanced. Our results indicate that the green, sustainable, adsorbent hydrogel may serve as a versatile platform for recovery, separation, and purification of rare earth ions and suggest its potential applications in the fields of hydrometallurgy industries and wastewater treatment.Keywords: Adsorption; Alginate; Clay; La (III); Poly(n-isopropylacrylamide) (PNIPAm);

In this study, we chose corn stover hemicellulose for the preparation of hydrogels with admirable adsorption properties under mild alkaline conditions. Clay nanosheets were introduced to this system and hemicellulose/clay hybrid hydrogels were prepared. Morphological, mechanical properties and the methylene blue adsorption behaviors of the prepared hydrogels were studied. Results suggested that the addition of clay not only improved the mechanical strength of hemicellulose-based hydrogels, but also increased the adsorption capacity on methylene blue. Moreover, the adsorptions were confirmed to follow pseudo-second order equation for both gels with and without clay. The maximum adsorption capacities on methylene blue for hemicellulose-based hydrogels with or without clay reached 148.8 and 95.6 mg/g, respectively. These results implied that hemicellulose-based hydrogels could be used as promising adsorbents for the removal of methylene blue from waste water.

This study describes a new strategy for the fabrication of magnetic core–shell microgels by free-radical polymerization triggered by the cascade reaction of glucose oxidase (GOx) and horseradish peroxidase (HRP). The mild polymerization around the interface of the magnetic nanoparticles permits the mild coating of the microgel layer with excellent characteristics for various applications in biocatalysis and medical diagnostics, as well as in clinical fields. The immobilized bienzyme within the microgel has a largely retained activity relative to the non-immobilized one. The confining effect of the microgel and the well designed distance between the two enzymes can benefit the diffusion of intermediates to the HRP active site. The final microgels can be incontestably employed as sensitive biosensors for colorimetric glucose detection.

Bio-inspired by bone materials, hierarchical porous materials with aligned structure have been designed and applied in various fields. However, the realization of anisotropic function based on aligned structures is still a challenge. Herein, we prepare nanocomposite ionogel electrolytes with aligned porous structures via a directional freezing of BMIMPF6, PEGMA (PEGDA), and TiO2 at −18 °C and further TiO2-initiated cryopolymerization under UV irradiation. The crystals of PEG derivatives at −18 °C provide a directional template for the formation of aligned porous structures within the ionogel networks. The additional TiO2 nanoparticles, as photoinitiators and nanofillers, endow the aligned ionogels with high mechanical strength. The aligned ionogel-based supercapacitor exhibits anisotropic electrochemical performance and flexibility. The specific capacitance of the device with the vertically aligned ionogel is 172 F g−1 at the current density of 1 A g−1, which is larger than those of the parallel aligned and non-aligned devices.

This communication describes the preparation of microgels via enzyme-triggered inverse emulsion polymerization, which provides an effective method for immobilizing enzymes with tunable catalytic performance and high stability.

This communication reports a mild preparation of a polymer/clay nanocomposite gel of chlorinated paraffin with an electrorheological response to an external direct-current (DC) voltage due to the alignment of the clay within the gel networks.

This communication reports the mild fabrication of a hydrogel-coated enzyme electrode for glucose detecting with high sensitivity (35.19 μA mM−1 cm−2) and robust stability.

A dual-enzyme-loaded multifunctional hybrid nanogel probe (SPIO@GCS/acryl/biotin-CAT/SOD-gel, or SGC) has been developed for dual-modality pathological responsive ultrasound (US) imaging and enhanced T2-weighted magnetic resonance (MR) imaging. This probe is composed of functionalized superparamagnetic iron oxide particles, a dual enzyme species (catalase and superoxide dismutase), and a polysaccharide cationic polymer glycol chitosan gel. The dual-modality US/MR imaging capabilities of the hybrid nanogel for responsive US imaging and enhanced T2-weighted MR imaging have been evaluated both in vitro and in vivo. These results show that the hybrid nanogel SGC can exhibit efficient dual-enzyme biocatalysis with pathological species for responsive US imaging. SGC also demonstrates increased accumulation in acidic environments for enhanced T2-weighted MR imaging. Further research on these nanogel systems may lead to the development of more efficient US/MR contrast agents.Keywords: hybrid nanogels; magnetic resonance imaging; pathological responsiveness; ultrasound imaging;

A new strategy for creating enzyme-responsive hydrogels by employing an N-hydroxyimide–heparin conjugate, designed to act as both an enzyme-mediated radical initiator and an enzyme-sensitive therapeutic carrier, is described. A novel enzyme-mediated redox initiation system involving glucose oxidase (GOx), an N-hydroxyimide–heparin conjugate and glucose is reported. The GOx-mediated radical polymerization reaction allows quick formation of hydrogels under mild conditions, with excellent flexibility in the modulation of the physical and chemical characteristics. The heparin-specific enzymatic cleavage reaction enables the delivery of cargo from the hydrogel in amounts that are controlled by the environmental levels of heparanase, which is frequently associated with tumor angiogenesis and metastasis. The formed hydrogels can realize cell-specific drug delivery by targeting cancer cells that are characterized by heparanase overexpression, whilst showing little toxicity towards normal cells.

Herein, we describe a supramolecular approach to synthesize tough ionogels through self-initiated ultraviolet polymerization. The prepared ionogel can be used as the integrated electrolyte and separator in the all-solid supercapacitor. The electrochemical performance can be tuned by the temperature, and a higher value can be achieved at higher temperature.

Fluorinated graphene is one of the most important two-dimensional carbon nanomaterials derived from graphene, and possesses specific and outstanding properties. However, it lacks a cost-effective and large-scale preparation method. Here, we describe a novel and facile solution approach using graphene oxide (GO) and liquid diethylaminosulfur trifluoride as starting materials under mild conditions. The chemical composition and the structure of so-prepared fluorinated graphene were characterized in detail by elemental analysis, solid state 19F NMR, XPS, FT-IR, Raman, SEM, TEM, and AFM. These studies reveal that some oxygen-containing moieties in GO are converted into C–F bonds, while some are eliminated during the reaction. More interestingly, the fluorine-loading amount can be well tuned by simply altering the reaction medium, and has a significant impact on the optical, electronic, and conductive properties of the product. Preliminary experiments on its application as an electrode material for solid-state supercapacitors were finally presented.

We report a facile solution polymerized approach to prepare nanocomposite hydrogels. The electrostatic assembly of positive TiO2 nanoparticles with negative clay nanosheets obtained TiO2–clay composite particles, which was disassembled by the solution polymerization of N,N-dimethylacrylamide and homogeneously interacted with poly(N,N-dimethylacrylamide) chain to form nanocomposite hydrogels. The final nanocomposite hydrogels are mechanical tough and transparent, which has the maximum 598.21 KPa compressive strength. The immobilized TiO2 not only acted as the photo-initiator for radical polymerization but also endowed the nanocomposite gel films good UV protective performance. This strategy can be very useful for preparing nanocomposite hydrogels with different functions.Keywords: electrostatic assembly; naocomposite hydrogel; photopolymerization; TiO2; UV protection;

Here, we provide an effective method to fabricate magnetic ZnO clay nanocomposite hydrogel via the photopolymerization. The inorganic components endow the hydrogel with high mechanical strength, while the organic copolymers exhibit good adsorption capacity and separation selectivity to La (III) ions. An optimized hydrogel has the maximum compressive stress of 316.60 ± 15.83 kPa, which still exhibits 138.98 ± 7.32 kPa compressive strength after swelling. The maximum adsorption capacity of La ion is 58.8 mg/g. The adsorption matches the pseudo-second-order kinetics model. La (III) ions can be effectively separated from the mixtures of La/Ni, La/Co, La/Cu, and La/Nd in a broad pH range (2.0 to 8.0). After six adsorption–desorption cycles, the hydrogel can maintain its adsorption capacity. This work not only provides a new approach to the synthesis of tough hydrogels under irradiation, but also opens up enormous opportunities to make full use of magnetic nanocomposite hydrogels in environmental fields.Keywords: clay; La (III) adsorption; magnetic separation; nanocomposite hydrogel; ZnO

This communication describes a mild construction of hybrid hydrogels with supramolecular-polymeric networks via a dual enzymatic reaction.

This communication demonstrates a convenient strategy to prepare a tough BSA–rGO hydrogel electrode via photopolymerization, which is demonstrated to be a highly effective H2O2 biosensor electrode with low detection concentration and high sensing sensitivity after combining with hemin chloride.

We describe the preparation of a thermoresponsive microgel, which can non-covalently immobilize active proteins with enhanced biocatalytic performance in organic solvents and easy reusability due to the porous microstructure and temperature responsive property.

This communication describes the mild and quick construction of tough nanocomposite hydrogels via a horseradish peroxidase-mediated radical polymerization for effectively immobilizing enzymes to attain high catalytic performance in various solvents.

A new approach has been developed to fabricate tough hybrid hydrogels by employing dual enzyme-mediated redox initiation to achieve post-self-assembly cross-linking polymerization. The resulting hydrogel combines the merits of supramolecular hydrogels with polymeric hydrogels to achieve higher mechanical strength and porous networks. Designed 3D constructs were fabricated via in situ 3D printing. The in situ immobilized GOx/HRP in Gel II exhibited superactivity compared to free enzymes, which might be attributed to the synergistic effect of co-localized GOx and HRP minimizing the distances for mass transport between the gel and the bulk solution. This mechanically strong hybrid hydrogel maintained high reusability and thermal stability as well. In addition, in situ 3D cell culture was demonstrated, thus indicating that this biodegradable hybrid hydrogel is biocompatible with cells. The subsequent 3D cell printing further indicates that the hybrid hydrogel is a promising scaffold for bio-related applications such as biocatalysis and tissue engineering.

We describe the preparation of a thermoresponsive microgel, which can non-covalently immobilize active proteins with enhanced biocatalytic performance in organic solvents and easy reusability due to the porous microstructure and temperature responsive property.

This communication demonstrates a convenient strategy to prepare a tough BSA–rGO hydrogel electrode via photopolymerization, which is demonstrated to be a highly effective H2O2 biosensor electrode with low detection concentration and high sensing sensitivity after combining with hemin chloride.

A new strategy for creating enzyme-responsive hydrogels by employing an N-hydroxyimide–heparin conjugate, designed to act as both an enzyme-mediated radical initiator and an enzyme-sensitive therapeutic carrier, is described. A novel enzyme-mediated redox initiation system involving glucose oxidase (GOx), an N-hydroxyimide–heparin conjugate and glucose is reported. The GOx-mediated radical polymerization reaction allows quick formation of hydrogels under mild conditions, with excellent flexibility in the modulation of the physical and chemical characteristics. The heparin-specific enzymatic cleavage reaction enables the delivery of cargo from the hydrogel in amounts that are controlled by the environmental levels of heparanase, which is frequently associated with tumor angiogenesis and metastasis. The formed hydrogels can realize cell-specific drug delivery by targeting cancer cells that are characterized by heparanase overexpression, whilst showing little toxicity towards normal cells.

This communication describes a mild construction of hybrid hydrogels with supramolecular-polymeric networks via a dual enzymatic reaction.

Hybrid hydrogels based on a guanidinium-containing oligopeptide are prepared via two dual-enzyme-triggered and simultaneous processes—self-assembly and polymerization. Furthermore, an extended time window is available for in situ viscosity-controlled 3D printing. In vivo hemostatic experiments elucidate that this guanidinium-containing hydrogel can accelerate the hemostasis process.

Bio-inspired by bone materials, hierarchical porous materials with aligned structure have been designed and applied in various fields. However, the realization of anisotropic function based on aligned structures is still a challenge. Herein, we prepare nanocomposite ionogel electrolytes with aligned porous structures via a directional freezing of BMIMPF6, PEGMA (PEGDA), and TiO2 at −18 °C and further TiO2-initiated cryopolymerization under UV irradiation. The crystals of PEG derivatives at −18 °C provide a directional template for the formation of aligned porous structures within the ionogel networks. The additional TiO2 nanoparticles, as photoinitiators and nanofillers, endow the aligned ionogels with high mechanical strength. The aligned ionogel-based supercapacitor exhibits anisotropic electrochemical performance and flexibility. The specific capacitance of the device with the vertically aligned ionogel is 172 F g−1 at the current density of 1 A g−1, which is larger than those of the parallel aligned and non-aligned devices.

Herein, we describe a supramolecular approach to synthesize tough ionogels through self-initiated ultraviolet polymerization. The prepared ionogel can be used as the integrated electrolyte and separator in the all-solid supercapacitor. The electrochemical performance can be tuned by the temperature, and a higher value can be achieved at higher temperature.

This communication describes the mild and quick construction of tough nanocomposite hydrogels via a horseradish peroxidase-mediated radical polymerization for effectively immobilizing enzymes to attain high catalytic performance in various solvents.

Fluorinated graphene is one of the most important two-dimensional carbon nanomaterials derived from graphene, and possesses specific and outstanding properties. However, it lacks a cost-effective and large-scale preparation method. Here, we describe a novel and facile solution approach using graphene oxide (GO) and liquid diethylaminosulfur trifluoride as starting materials under mild conditions. The chemical composition and the structure of so-prepared fluorinated graphene were characterized in detail by elemental analysis, solid state 19F NMR, XPS, FT-IR, Raman, SEM, TEM, and AFM. These studies reveal that some oxygen-containing moieties in GO are converted into C–F bonds, while some are eliminated during the reaction. More interestingly, the fluorine-loading amount can be well tuned by simply altering the reaction medium, and has a significant impact on the optical, electronic, and conductive properties of the product. Preliminary experiments on its application as an electrode material for solid-state supercapacitors were finally presented.

Dynamic hydrogels were prepared via an oxidative deamination reaction catalyzed by monoamine oxidase B. Amino-containing polysaccharides (or proteins) and oxidative products (aldehydes) formed the dynamic Schiff base linkages, which endowed the hydrogel with excellent self-healing and multiresponsive properties.

The preparation of thin gel electrolyte membranes with controllable thickness is important to explore the thickness-dependent electrochemical behaviors; this can further guide the fabrication of energy devices. Here we employ an in situ polymerization method to prepare a BSA–PDMAA–SiO2 cross-linked nanocomposite hydrogel on surfaces of eggshell membranes, which can be used as integrated separator and electrolyte in a supercapacitor after absorbing the electrolyte. The novel controlled thickness of the coated hydrogel therefore offers superior space utilization essential for all-solid-state devices. The composite gel can reach a high ionic conductivity of 8.8 mS cm−1 and a resulting Csp value of 161 F g−1 at the current density of 1 A g−1 when assembled in the supercapacitor, while the eggshell membrane based device has limited values of 2.7 mS cm−1 and 88 F g−1. A new insight into hybrid material preparation from low-cost natural life waste is presented in this work to obtain high performance gel electrolytes in energy devices.

Nanozymes merge nanotechnology with biology and provide a lower cost and higher stability options, compared to that of natural enzymes. However, nanozyme catalyzed polymerization under physiological conditions is still a big challenge due to heavy oxygen inhibition. In this study, the simple glucose oxidase system can effectively adjust oxygen concentration and generate hydrogen peroxide, which assists in the realization of nanozyme-catalyzed polymerization. The nanozyme based hydrogel is printable due to its mild preparation with gradually increased viscosity. The antibacterial performance is ascribed to the in situ generated hydroxyl radical via the reaction of the bound nanozyme and glucose.