A nano-composite hyaluronic acid-based hydrogel efficiently antibacterial and scavenges ROS for promoting infected diabetic wound healing.

Diabetic wound infection brings chronic pain to patients and the therapy remains a crucial challenge owing to the disruption of the internal microenvironment. Herein, we report a nano-composite hydrogel (ZnO@HN) based on ZnO nanoparticles and a photo-trigging hyaluronic acid which is modified by o-nitrobenzene (NB), to accelerate infected diabetic wound healing. The diameter of the prepared ZnO nanoparticle is about 50 nm. X-ray photoelectron spectroscopy (XPS) analysis reveals that the coordinate bond binds ZnO in the hydrogel, rather than simple physical restraint. ZnO@HN possesses efficient antioxidant capacity and it can scavenge DPPH about 40 % in 2 h and inhibit H2O2 >50 % in 8 h. The nano-composite hydrogel also exhibits satisfactory antibacterial capacity (58.35 % against E. coli and 64.03 % against S. aureus for 6 h). In vitro tests suggest that ZnO@HN is biocompatible and promotes cell proliferation. In vivo experiments reveal that the hydrogel can accelerate the formation of new blood vessels and hair follicles. Histological analysis exhibits decreased macrophages, increased myofibroblasts, downregulated TNF-α expression, and enhanced VEGFA expression during wound healing. In conclusion, ZnO@HN could be a promising candidate for treating intractable infected diabetic skin defection.

A multi-functional double cross-linked chitosan hydrogel with tunable mechanical and antibacterial properties for skin wound dressing.

Chitosan hydrogels with essential antibacterial properties and biocompatibility have great potential in tissue engineering and regeneration medicine. However, pure chitosan hydrogel could be limited by insufficient mechanical properties. In this work, we designed a multi-functional chitosan hydrogel based on the combination of chitosan methacrylate (CTSMA) and sulfhydrated chitosan (CTSSH), which is cross-linked simultaneously by free-radical polymerization reaction and Thiol-ene reaction. The CTSMA/CTSSH (CMS) hydrogels displayed superior tissue adhesive and mechanical properties when compared to pure CTSMA hydrogel. Additionally, the resulting hydrogels exhibited potent antimicrobial effects against both E. coli and S. aureus. Besides, the CMS hydrogels exhibited good biocompatibility as demonstrated by cytotoxicity and cell proliferation experiments using fibroblasts cells (L929) and adipose-derived stem cells (ADSCs). In vivo experiment, the repairing effect of hydrogels on full-thickness skin defect model in rats was studied. Histological and immunohistochemical staining results showed that CMS hydrogels promoted angiogenesis, dermal repair and epidermal regeneration. Overall, the study highlights the potential of the CMS hydrogels as a promising biomaterial in wound healing applications.

Revisiting matrix hydrogel composed of gelatin and hyaluronic acid and its application in cartilage regeneration.

With the increasing incidence of knee osteoarthritis (KOA), the reparation of cartilage defects is gaining more attention. Given that tissue integration plays a critical role in repairing cartilage defects, tissue adhesive hydrogels are highly needed in clinics. We constructed a biomacromolecule-based bioadhesive matrix hydrogel and applied it to promote cartilage regeneration. The hydrogel was composed of methacrylate gelatin and N-(2-aminoethyl)-4-(4-(hydroxymethyl)-2-methoxy-5-nitroso) butyl amide modified hyaluronic acid (HANB). The methacrylate gelatin provided a stable hydrogel network as a scaffold, and the HANB served as a tissue-adhesive agent and could be favorable for the chondrogenesis of stem cells. Additionally, the chemically modified HA increased the swelling ratio and compressive modulus of the hydrogels. The results of our in vitro study revealed that the hydrogel was compatible with bone marrow stromal cells. In vivo, the hyaluronic-acid-containing hydrogels were found to promote articular cartilage regeneration in the defect site. Therefore, this biomaterial provides promising potential for cartilage repair.

Chondroitin Sulfate Improves Mechanical Properties of Gelatin Hydrogel for Cartilage Regeneration in Rats.

Cartilage injury is a common disease in daily life. Especially in aging populations, the incidence of osteoarthritis is increasing. However, due to the poor regeneration ability of cartilage, most cartilage injuries cannot be effectively repaired. Even cartilage tissue engineering still faces many problems such as complex composition and poor integration of scaffolds and host tissues. In this study, chondroitin sulfate, one of the main components of extracellular matrix (ECM), is chosen as the main natural component of the material, which can protect cartilage in a variety of ways. Moreover, the results show that the addition of chondroitin sulfate improves the mechanical properties of gelatin methacrylate (GelMA) hydrogel, making it able to effectively bear mechanical loads in vivo. Further, chondroitin sulfate is modified to obtain the oxidized chondroitin sulfate (OCS) containing aldehyde groups via sodium periodate. This special group improves the interface integration and adhesion ability of the hydrogel to host cartilage tissue through schiff base reactions. In summary, GelMA/OCS hydrogel is a promising candidate for cartilage regeneration with good biocompatibility, mechanical properties, tissue integration ability, and excellent cartilage repair ability.

Protocol for preparation of a photo-triggering double cross-linked adhesive, antibacterial, and biocompatible hydrogel for wound healing.

The treatment of full-thickness skin wounds represents a major clinical challenge, and hydrogel is regarded as a promising class of biomaterials for wound repair. Here, we present a protocol for preparing a photo-triggering double cross-linked, adhesive, antibacterial, and biocompatible hydrogel. We describe the steps to prepare the hydrogel and evaluate its mechanical performance, swelling kinetics, antibacterial property, biocompatibility in vitro, and therapeutic effect in vivo. This protocol is also applicable to other defect models of wound injury. For complete details on the use and execution of this protocol, please refer to our previous work.1.

An adhesive gelatin-coated small intestinal submucosa composite hydrogel dressing aids wound healing.

It is a challenging clinical task to determine how to repair large-area skin defects better. Traditional wound dressings (e.g., cotton and gauze) can only be used as a dressing; consequently, there is an increasing demand for wound dressings with additional properties (i.e., antibacterial and pro-repair) in clinical practice. In this study, a composite hydrogel with o-nitrobenzene-modified gelatin-coated decellularized small intestinal submucosa (GelNB@SIS) was designed for the repair of skin injuries. SIS is a natural extracellular matrix with a 3D microporous structure and also contains high levels of growth factors and collagen. GelNB provides this material photo-triggering tissue adhesive property. The structure, tissue adhesion, cytotoxicity, and bioactivity to cells were investigated. Based on in vivo study and histological analysis, we found the combination of GelNB and SIS improved the healing process by promoting vascular renewal, dermal remodeling, and epidermal regeneration. Based on our findings, GelNB@SIS is a promising candidate for tissue repair applications.

A Dual-Crosslinked Hydrogel Based on Gelatin Methacryloyl and Sulfhydrylated Chitosan for Promoting Wound Healing.

The skin is the largest organ of the human body. Skin injuries, especially full-thickness injuries, are a major treatment challenge in clinical practice. Therefore, wound dressing materials with therapeutic effects have great practical significance in healthcare. This study used photocrosslinkable gelatin methacryloyl (GelMA) and sulfhydrylated chitosan (CS-SH) to design a double-crosslinked hydrogel for wound dressing. When crosslinked together, the resulting hydrogels showed a highly porous inner structure, and enhanced mechanical properties and moisture retention capacity. The compression modulus of the GelMA/CS-SH hydrogel (GCH) reached up to about 40 kPa and was much higher than that of pure GelMA hydrogel, and the compression modulus was increased with the amount of CS-SH. In vitro study showed no cytotoxicity of obtained hydrogels. Interestingly, a higher concentration of CS-SH slightly promoted the proliferation of cells. Moreover, the double-crosslinked hydrogel exhibited antibacterial properties because of the presence of chitosan. In vivo study based on rats showed that full-thickness skin defects healed on the 15th day. Histological results indicate that the hydrogel accelerated the repair of hair follicles and encouraged the orderly growth of collagen fibers in the wound. Furthermore, better blood vessel formation and a higher expression of VEGFR were observed in the hydrogel group when compared with the untreated control group. Based on our findings, GCH could be a promising candidate for full-thickness wound dressing.

A photo-triggering double cross-linked adhesive, antibacterial, and biocompatible hydrogel for wound healing.

Full-thickness wounds, lacking the epidermis and entire dermis and extending into subcutaneous fat, represent a common treatment challenge. Due to the loss of adnexal structures as a source of keratinocytes, full-thickness wounds healing can only be achieved by re-epithelialization from the wound edge and contraction. Here, we developed a hydrogel composed of chitosan methacrylate (CSMA) and o-nitrosobenzaldehyde-modified gelatin (GelNB) for promoting full-thickness wound healing. The CSMA/GelNB (CM/GN) hydrogels exhibited superior mechanical and adhesive properties than that of pure CSMA hydrogel. In vivo experiments confirmed that CM/GN could promote wound healing by generating more hair follicles and mutual blood vessels, high fibroblasts density, and thicker granulation tissue thickness. In addition, reduced secretions of tumor necrosis factor-α (TNF-α) and enhanced secretions of vascular endothelial growth factor (VEGF) could be observed in regenerated tissues after CM/GN treatment. These results suggested that CM/GN hydrogels could be promising candidates to promote wound healing.

A benzaldehyde-indole fused chromophore-based fluorescent probe for double-response to cyanide and hypochlorite in living cells.

With the rapid development of various industries, cyanide (CN-) and hypochlorite (ClO-) have a tremendously adverse effect on the health of humans and animals. In this study, a fluorescent probe HHTB based on a benzaldehyde-indole fused chromophore was designed to detect cyanide and hypochlorite simultaneously. The synthesized probe was found to have strong anti-interference ability. In addition, the designed probe could respond rapidly to ClO- in just 80 s, while the color changed visibly from red to colorless. Moreover, the response time to CN- was longer (about 160 s), with the apparent color change from red to light red. The ratiometric and colorimetric absorbance variation of HHTB was due to the nucleophilic attack of CN- on the indole CN functional group and the strong oxidization of ClO- which destroyed the CC bonds and the conjugation systems. Furthermore, the probe HHTB responding to ClO- and CN- presented high sensitivity, as the calculated detection limits were 1.18 nM and 1.40 nM, respectively. The probe was also found to have low biological toxicity and was used in living cells successfully. Therefore, it has good application prospect in the field of cell imaging and biomedicine. The binding mechanism of HHTB-CN and the reaction mechanism of HHTB and ClO- were further elucidated by a series of experiments.

Fast preparation of Fe3O4@polydopamine/Au for highly efficient degradation of tetracycline.

This work reported the fast synthesis of magnetic polydopamine Au-Fenton catalyst (Fe3O4@PDA/Au) under UV irradiation at 365 nm. The microstructure of prepared nanocomposites was characterized by various techniques. The effects of several key factors (pH values, H2O2 content and TC concentration) of tetracycline (TC) degradation were evaluated. The results revealed that the TC and total organic carbon (TOC) removal rate reached up to 98.16% and 93.14% within 300 min under optimal conditions (pH 3, H2O2 80 µL, TC concentration 20 mg/L). Besides, HO radicals were generated during the Fenton-like degradation process and the plausible degradation mechanism was discussed. Moreover, Fe3O4@PDA/Au catalyst retained excellent catalytic capacity (TC removal rate 96.94% and TOC removal rate 87.69%) and exhibited fantastic stability after six cycles. Moreover, metal ions leaching was evaluated (0.023 mg/L). Altogether, the novel Fe3O4@PDA/Au Fenton-like catalyst is highly promising for wastewater management.

Highly efficient removal of antibiotic from biomedical wastewater using Fenton-like catalyst magnetic pullulan hydrogels.

Magnetic nanoparticles that can be employed as Fenton-like catalysts Fenton-like catalysts are attractive materials for degrading antibiotics. In this study, we facilely prepared novel magnetic pullulan (MP) hydrogels by doping modified magnetic nanoparticles into pullulan matrices, which could enhance catalytic degradation performance and strengthen the stability of resulting hydrogels. This is the first time that MP hydrogels have been fabricated successfully and used as Fenton-like catalysts for tetracycline hydrochloride (TCH) degradation. MP hydrogels were characterized and their catalytic TCH degradation abilities were also investigated. The optimized conditions (pH value, Fe3O4 content, H2O2 content and TCH concentration) for TCH degradation were investigated. The optimized system showed excellent degradation efficiency for TCH. Further, the degradation mechanism was comprehensively studied. Finally, synthesized MP hydrogels showed impressive reusability and stability in the cycle experiment. Thus, our findings would open new possibilities to develop magnetic hydrogels in eliminating antibiotic contaminants.