Photocrosslinkable, Injectable Locust Bean Gum Hydrogel Induces Chondrogenic Differentiation of Stem Cells for Cartilage Regeneration.

Due to the limited therapeutic efficacy of current treatments, articular cartilage regeneration is still challenging work. Scaffold-based tissue engineering provides a promising strategy for cartilage regeneration, but most scaffolds are limited by poor mechanical properties or unfavorable biocompatibility. Here, a novel photocrosslinkable, injectable locust bean gum (LBG)-methacrylate (MA) hydrogel is reported as a biomimetic extracellular matrix (ECM) for cartilage repair with minimal invasive operation. LBG-MA hydrogels show controllable degradation rate and improve mechanical properties and excellent biocompatibility. More importantly, LBG-MA hydrogel significantly induces bone mesenchymal stem cells to chondrogenic differentiation in vitro, as evidenced by high accumulation of cartilage-specific ECM components glycosaminoglycan and upregulated expression of key chondrogenic genes (collagen type II, aggrecan, and sex determining region Y-box9). Besides, the hydrogel is injectable, which can be in situ crosslinked via UV irradiation. Further, the photocrosslinkable hydrogels accelerate cartilage healing in vivo after 8 weeks of therapy. A strategy is provided here for photocrosslinkable, injectable, biodegradable scaffold fabrication based on native polysaccharide polymer for minimal invasive cartilage repair.

RhRu Alloy-Anchored MXene Nanozyme for Synergistic Osteosarcoma Therapy.

Noble metal nanozymes hold promise in cancer therapy due to adjustable enzyme-like activities, unique physicochemical properties, etc. But catalytic activities of monometallic nanozyme are confined. In this study, 2D titanium carbide (Ti3 C2 Tx )-supported RhRu alloy nanoclusters (RhRu/Ti3 C2 Tx ) are prepared by a hydrothermal method and utilized for synergistic therapy of chemodynamic therapy (CDT), photodynamic therapy (PDT), and photothermal therapy (PTT) on osteosarcoma. The nanoclusters are small in size (3.6 nm), uniform in distribution, and have excellent catalase (CAT) and peroxidase (POD)-like activities. Density functional theory calculations show that there is a significant electron transfer interaction between RhRu and Ti3 C2 Tx , which has strong adsorption to H2 O2 and is beneficial to enhance the enzyme-like activity. Furthermore, RhRu/Ti3 C2 Tx nanozyme acts as both PTT agent for converting light into heat, and photosensitizer for catalyzing O2 to 1 O2 . With the NIR-reinforced POD- and CAT-like activity, excellent photothermal and photodynamic performance, the synergistic CDT/PDT/PTT effect of RhRu/Ti3 C2 Tx on osteosarcoma is verified by in vitro and in vivo experiments. This study is expected to provide a new research direction for the treatment of osteosarcoma and other tumors.

Application of the pH-Responsive PCL/PEG-Nar Nanofiber Membrane in the Treatment of Osteoarthritis.

Electrospinning technology is widely used in the field of drug delivery due to its advantages of convenience, high efficiency, and low cost. To investigate the therapeutic effect of naringenin (Nar) on osteoarthritis (OA), the pH-responsive system of the polycaprolactone/polyethylene glycol-naringenin (PCL/PEG-Nar) nanofiber membrane was designed and used as drug delivery systems (DDS) in the treatment of OA. The PEG-Nar conjugate was constructed via ester linkage between mPEG-COOH and the carboxyl group of naringenin, and the PCL/PEG-Nar nanofiber membrane was prepared by electrospinning technology. When placed in the weak acid OA microenvironment, the PCL/PEG-Nar nanofiber membrane can be cleverly "turned on" to continuously release Nar with anti-inflammatory effect to alleviate the severity of OA. In this study, the construction and the application of the pH-responsive PCL/PEG-Nar nanofiber membrane drug delivery platform would throw new light on OA treatment.

Electrospun PCL/MoS2 Nanofiber Membranes Combined with NIR-Triggered Photothermal Therapy to Accelerate Bone Regeneration.

Electrospun nanofiber membranes have been widely used for guided bone regeneration (GBR). For assistance in bone healing, photothermal therapy which renders moderate heat stimulation to defect regions by near-infrared (NIR) light irradiation has attracted much attention in recent years. Combined with photothermal therapy, novel electrospun poly(ε-caprolactone)/molybdenum disulfide (PCL/MoS2 ) nanofiber membranes are innovatively synthesized as GBR for bone therapy, wherein the exfoliated MoS2 nanosheets served as osteogenic enhancers and NIR photothermal agents. With the doping of MoS2 , the mechanical properties of nanofiber membranes got improved with the degradation unaffected. The composite PCL/MoS2 membranes show enhanced cell growth and osteogenic performance compared with PCL alone. Under NIR-triggered mild photothermal therapy, osteogenesis and bone healing are accelerated by using PCL/MoS2 nanofiber membranes for growth of bone mesenchymal stem cells in vitro and repair of rat tibia bone defect in vivo. The novel nanofiber membranes may be developed as intelligent GBR in the therapy of bone defects.

Functionalised molybdenum disulfide nanosheets for co-delivery of doxorubicin and siRNA for combined chemo/gene/photothermal therapy on multidrug-resistant cancer.

OBJECTIVE: Molybdenum disulfide (MoS2) has been developed for medical uses due to its excellent medically beneficial characteristics. This research was designed to develop a multifunctional nano-drug delivery system based on the nano-structure of MoS2 for combined chemo/gene/photothermal therapy targeting multidrug-resistant cancer. METHODS: MoS2 nanosheets were prepared by a hydrothermal reaction and modified. Afterward, the nanocarrier was characterised. In vitro cytotoxicity of the drug delivery systems on human breast adenocarcinoma cell lines was assessed. KEY FINDINGS: The nanocarrier was a flake-like structure with a uniform hydrodynamic diameter and possessing good colloidal stability. The nanocarrier showed the capacity to be deployed for co-delivery of Doxorubicin (DOX) and siRNA. The release of DOX could be triggered and enhanced by pH and application of near-infrared (NIR) laser. The nanocarrier had a good photothermic response and stability. The nanocarrier had little effect on the cells and exhibited good biocompatibility. Measurement of the therapeutic efficacy showed that synergistic therapy combining chemo-, gene- and photothermal therapy deploying this drug delivery system will achieve a better anticancer effect on drug-resistant cancer cells than DOX alone. CONCLUSIONS: Our results suggest that this drug delivery system has potential application in the therapeutic strategy for drug-resistant cancer.

Printable hybrid hydrogel by dual enzymatic polymerization with superactivity.

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.

Microgel coating of magnetic nanoparticles via bienzyme-mediated free-radical polymerization for colorimetric detection of glucose.

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.

Bioinorganic nanocomposite hydrogels formed by HRP-GOx-cascade-catalyzed polymerization and exfoliation of the layered composites.

The mild preparation of multifunctional nanocomposite hydrogels is of great importance for practical applications. We report that bioinorganic nanocomposite hydrogels, with calcium niobate nanosheets as cross-linkers, can be prepared by dual-enzyme-triggered polymerization and exfoliation of the layered composite. The layered HRP/calcium niobate composites (HRP=horseradish peroxidase) are formed by the assembly of the calcium niobate nanosheets with HRP. The dual-enzyme-triggered polymerization can induce the subsequent exfoliation of the layered composite and final gelation through the interaction between polymer chains and inorganic nanosheets. The self-immobilized HRP-GOx enzymes (GOx=glucose oxidase) within the nanocomposite hydrogel retain most of enzymatic activity. Evidently, their thermal stability and reusability can be improved. Notably, our strategy could be easily extended to other inorganic layered materials for the fabrication of other functional nanocomposite hydrogels.

Magnetic nanocomposite hydrogel prepared by ZnO-initiated photopolymerization for La (III) adsorption.

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.

Dual enzymatic formation of hybrid hydrogels with supramolecular-polymeric networks.

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

Molecular hydrogel-stabilized enzyme with facilitated electron transfer for determination of H2O2 released from live cells.

In this work, small molecular hydrogel was first employed as a surrounding matrix to stabilize an enzyme model, Cytochrome c (Cyt c), and more importantly to facilitate electron transfer between redox enzyme and electrode. Direct electron transfer of Cyt c was successfully achieved in the molecular hydrogel with redox formal potential (E(0')) of 100.7 ± 3.2 mV versus Ag|AgCl and heterogeneous electron transfer rate constant (ks) up to 18.6 ± 2.3 s(-1). Experimental data demonstrated that Cyt c was stably immobilized into the molecular hydrogel and retained its inherent bioactive activity toward H2O2. The direct redox reaction of Cyt c, followed by the biochemical reaction between Cyt c and H2O2, established a reliable approach to determine H2O2 at an optimized potential with high selectivity over other reactive oxygen species (ROS), oxygen, metal ions, ascobic acid (AA), and so on. In addition, the present biosensor for H2O2 also exhibited wide linear range and low detection limit, which fulfills the requirements for detection of H2O2 in a biological system. The remarkable analytical performance of the present biosensor, as well as the long-term stability and good reproducibility ascribed to the molecular hydrogel-stabilized enzyme, provided a durable platform for real-time determination of H2O2 from live cells.

Nanocomposite gels via in situ photoinitiation and disassembly of TiOTiO2-clay composites with polymers applied as UV protective films.

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.