Hydrogel coating based on dopamine-modified hyaluronic acid and gelatin with spatiotemporal drug release capacity for quick endothelialization and long-term anticoagulation

Current trend on preparation, characterization and biomedical applications of natural polysaccharide-based nanomaterial reinforcement hydrogels: A review

The tunable properties of hydrogels have led to their widespread use in various biomedical applications such as wound treatment, drug delivery, contact lenses, tissue engineering and 3D bioprinting. Among these applications, natural polysaccharide-based hydrogels, which are fabricated from materials like agarose, alginate, chitosan, hyaluronic acid, cellulose, pectin and chondroitin sulfate, stand out as preferred choices due to their biocompatibility and advantageous fabrication characteristics. Despite the inherent biocompatibility, polysaccharide-based hydrogels on their own tend to be weak in physiochemical and mechanical properties. Therefore, further reinforcement in the hydrogel is necessary to enhance its suitability for specific applications, ensuring optimal performance in diverse settings. Integrating nanomaterials into hydrogels has proven effective in improving the overall network and performance of the hydrogel. This approach also addresses the limitations associated with pure hydrogels. Next, an overview of recent trends in the fabrication and applications of hydrogels was presented. The characterization of hydrogels was further discussed, focusing specifically on the reinforcement achieved with various hydrogel materials used so far. Finally, a few challenges associated with hydrogels by using polysaccharide-based nanomaterial were also presented.

Mussel-Mimetic Hydrogel Coating with Anticoagulant and Antiinflammatory Properties on a Poly(lactic acid) Vascular Stent

Biodegradable stents are the most promising alternatives for the treatment of cardiovascular disease nowadays, and the strategy of preparing functional coatings on the surface is highly anticipated for addressing adverse effects such as in-stent restenosis and stent thrombosis. Yet, inadequate mechanical stability and biomultifunctionality limit their clinical application. In this study, we developed a multicross-linking hydrogel on the polylactic acid substrates by dip coating that boasts impressive antithrombotic ability, antibacterial capability, mechanical stability, and self-healing ability. Gelatin methacryloyl, carboxymethyl chitosan, and oxidized sodium alginate construct a double-cross-linking hydrogel through the dynamic Schiff base chemical and in situ blue initiation reaction. Inspired by the adhesion mechanism employed by mussels, a triple-cross-linked hydrogel is formed with the addition of tannic acid to increase the adhesion and antibiofouling properties. The strength and hydrophilicity of hydrogel coating are regulated by changing the composition ratio and cross-linking degree. It has been demonstrated in tests in vitro that the hydrogel coating significantly reduces the adhesion of proteins, MC3T3-E1 cells, platelets, and bacteria by 85% and minimizes the formation of blood clots. The hydrogel coating also exhibits excellent antimicrobial in vitro and antiinflammatory properties in vivo, indicating its potential value in vascular intervention and other biomedical fields.

Bioinspired adhesive hydrogel based on serotonin-modified gelatin and oxidized hyaluronic acid for rapid hemostasis and wound healing

A hybrid hydrogel system (GSOHA) consisting of serotonin-grafted gelatin and oxidized hyaluronic acid (OHA) was developed in this study to efficiently control bleeding and prevent bacterial infections during surgery and trauma. The study results showed that the incorporation of serotonin successfully produced hydrogels with rapid hemostatic, antibacterial, and antioxidant properties. The GSOHA hydrogel exhibited considerably stronger tissue adhesion (15.55 ± 0.36 kPa) to porcine skin than the commercial fibrin glue (1.09 ± 0.04 kPa). In addition, the hydrogel could rapidly absorb blood cells and stimulate cell conjugation with serotonin addition. In vitro experiments using endothelial cells and erythrocytes demonstrated the excellent biocompatibility and hemocompatibility of the hydrogel. Most importantly, the GSOHA hydrogel accelerated the wound healing process in a full-thickness skin defect mice model, and the histological staining results demonstrated that GSOHA significantly promoted collagen deposition and vascularization. In conclusion, this study demonstrated the significant potential of the GSOHA hydrogel as an adhesive dressing for rapid hemostasis and wound healing.

Hydrophobically modified hydrogel with enhanced tissue adhesion and antibacterial capacity for wound healing

The increasing emergence of drug-resistant bacteria and bacteria-infected wounds highlights the urgent need for new kinds of antibacterial wound dressing. Herein, we reported a novel bio-adhesive and antibacterial hydrogel consisting of hydrophobically modified gelatin, oxidized konjac glucomannan, and dopamine. This kind of functional hydrogel was endowed with developed stability in a liquid environment and strong tissue adhesion, even much higher than the commercial fibrin glue to wounds. The excellent bacteria-killing efficiency of hydrophobically modified hydrogel against S. aureus and E. coli was verified, as well as the low hemolysis ratio against erythrocytes in vitro. The hydrogel also exhibited good cytocompatibility in terms of supporting cell proliferation. Most importantly, these abovementioned properties could be customized by altering the substitution degree of hydrophobic groups during manufacturing, demonstrating its great potential in biomedical fields such as tissue adhesive and wound dressing.