A di-self-crosslinking hyaluronan-based hydrogel combined with type I collagen to construct a biomimetic injectable cartilage-filling scaffold

Injectable hydrogels have attracted increasing attention because of convenient clinical operation, non-invasive surgical procedure and seamless filling of irregular defects. Here, injectable di-self-crosslinking HSMSSA hydrogel was formed via fast thiol/maleimide click chemistry reaction and thiol oxidation reaction as primary and secondary self-crosslinking network, respectively. Molecular weight and precursor concentration significantly affected physichemical properties and biological functions of hydrogels. Although single HSMSSA gel (0.1 M Da, 10 mg/mL) had moderate injectability, preferable mechanical properties and good proliferative ability of chondrocytes in vitro, and could greatly promote cartilaginous tissue formation in vivo, the lack of adhesion sites resulted in an untenable situation in maintaining effective connections among newborn cell clusters. However, the biomimetic injectable di-self-crosslinking blend hydrogel by combing injectable HSMSSA and bioactive Col I had improved resistance to degradation, chondrocytes adhesion and proliferation, especially for multiples ascending genes expression level associated with hyaline cartilage formation and polyproteoglycan secretion, which might be a potential clinical treatment strategy for constructing injectable cartilage repair filler by combining expanded autologous chondrocytes. STATEMENT OF SIGNIFICANCE: An injectable di-self-crosslinking Hyaluronan-Based hydrogel was formed via fast thiol/maleimide click chemistry reaction and thiol oxidation reaction as primary/secondary self-crosslinking network, respectively. Molecular weight and precursor concentration significantly affected physichemical properties and biological functions of the hydrogels. Although this HSMSSA gel (0.1 M Da, 10 mg/mL) had moderate injectability, preferable mechanical properties, and good proliferative ability of chondrocytes in vitro, and could greatly promote cartilaginous tissue formation in vivo, the lack of adhesion sites resulted in ineffective connections among newborn cell clusters. The biomimetic injectable di-self-crosslinking blend hydrogel improved chondrocyte adhesion and proliferation by combined injectable HSMSSA and bioactive Col I, especially for multiple ascending gene expression levels associated with hyaline cartilage formation and polyproteoglycan secretion.

Hybrid granular hydrogels: combining composites and microgels for extended ranges of material properties

Developing hydrogels with optimal properties for specific applications is challenging as most of these properties, such as toughness, stiffness, swelling or deformability, are interrelated. The improvement of one property usually comes at the cost of another. In order to decouple the interdependence between these properties and to extend the range of material properties for hydrogels, we propose a strategy that combines composite and microgel approaches. The study focuses first on tailoring the swelling performance of hydrogels while minimally affecting other properties. The underlying principle is to partially substitute some of the hydrogels with pre-swollen microgels composed of the same materials. Swelling reductions up to 45% were obtained. Those granular hydrogels were then reinforced with nano-fibrillated cellulose fibres obtaining hybrid granular materials to improve their toughness and to further reduce their initial swelling. Four different structures of neat, granular and composite hydrogels including 63 different hydrogel compositions based on 20 kDa poly(ethylene glycol)dimethacrylate showed that the swelling ratio could be tailored without significantly affecting elastic modulus and deformation performance. The results explain the role of the PEGDM precursors on the swelling of the microgels as well as the influence of the microgel and fibre contents on the final properties. Moreover, the precursors of hydrogels with similar mechanical or swelling performance were injectable with a wide range of complex viscosities from 0.1 Pa s to over 1000 Pa s offering new opportunities for applications in confined as well as in unconfined environments.

One-Pot Synthesis of a Copolymer Micelle Crosslinked Binder with Multiple Lithium-Ion Diffusion Pathways for Lithium-Sulfur Batteries

Fast lithium-ion diffusion is very important to obtain high capacity and excellent cycling stability of lithium-sulfur batteries. In this study, a copolymer micelle crosslinked binder (FNA) for lithium-sulfur batteries was successfully synthesized through a one-pot environmentally friendly approach. The micelles were used as crosslinkers and carriers for the electrolyte. The FNA binder provided multiple lithium-ion diffusion pathways to increase the lithium-ion diffusion, which reduced the polarization of the sulfur cathode during the cycling process. The lithium-ion diffusion pathways of the FNA were provided by the electrolyte hosted in the micelles, the polyethylene oxide and polypropylene oxide segments, and the carboxylate and sulfonate groups in the FNA. In addition, FNA possesses strong lithium polysulfides adsorption and high adhesion properties. Therefore, the electrode with the FNA binder presented a reversible capacity of 571 mAh g^-1 with a capacity fade of 0.032 % after 1000 cycles at a cycling rate of 0.5 C, which is much higher than those of the polyvinylidene fluoride (PVDF) sulfur cathode.

Dual-enzymatically crosslinked and injectable hyaluronic acid hydrogels for potential application in tissue engineering

Recently, in situ formed injectable hydrogels have shown great potential in biomedical applications as therapeutic implants or carriers in tissue repair and regeneration. They can seal or fill the damaged tissue to function as cell/drug delivery vehicle perfectly through a minimally invasive surgical procedure. In this study, hyaluronic acid (HA) is functionalized with tyramine to produce an injectable hydrogel dual-enzymatically crosslinked by horseradish peroxidase (HRP) and galactose oxidase (GalOX). This new tyramine-modified HA (HT) hydrogel exhibited good injectability, favorable cytocompatibility to mice bone marrow mesenchymal stem cells (BMSCs), and low inflammatory response verified by cytotoxicity assay in vitro and an in situ subcutaneous injection study in vivo. In addition, the gelation time, swelling behavior, and degradation rate of the HT hydrogel could be adjusted through varying the concentrations of HT and GalOX in a certain range. These encouraging results suggest that such biocompatible HT hydrogels might have potential application in three-dimensional stem cell culture and tissue engineering.

A new hyaluronic acid hydrogel dual-enzymatically cross-linked by HRP and GalOX and application for three-dimensional stem cell culture and tissue engineering.

Robust alginate/hyaluronic acid thiol-yne click-hydrogel scaffolds with superior mechanical performance and stability for load-bearing soft tissue engineering

Hydrogels based on hyaluronic acid (HA) exhibit great potential as tissue engineering (TE) scaffolds as a consequence of their unique biological features. Herein, we examine how the advantages of two natural polymers (i.e. HA and alginate) are combined with the efficiency and rapid nature of the thiol-yne click chemistry reaction to obtain biocompatible matrices with tailored properties. Our injectable click-hydrogels revealed excellent mechanical performance, long-term stability, high cytocompatibility and adequate stiffness for the targeted application. This simple approach yielded HA hydrogels with characteristics that make them suitable for applications as 3D scaffolds to support and promote soft tissue regeneration.