| Wound healing is one of the more common and extremely difficult problems in life.In the process of wound healing,bacterial infection can cause chronic inflammation in the wound and cause the wound to fail to heal for a long time.Therefore,antibacterial hydrogels used to control infection have become a research hotspot.Natural polymers are widely used in biomedicine,pharmaceutical and food packaging fields due to their biocompatibility,biodegradability and low toxicity.Among them,gelatin,as a natural polymer,is a hydrolysate of collagen,the main component of natural extracellular matrix(ECM).Compared with collagen,gelatin has better solubility and less antigenicity.Proliferation has a good effect and has the potential as a wound dressing material.However,gelatin-based materials have poor mechanical properties,poor thermal stability,and relatively short degradation rates.When used in studies that require a longer period of time(drug release,cell differentiation,and wound healing),gelatin-based materials may not last.Therefore,the mechanical stability,biocompatibility and biological activity of the material can be improved by modifying gelatin and making gelatin composite materials.In this thesis,gelatin is used as the matrix material,and bacteriostatic molecules or natural polymers with bacteriostatic properties are compounded by chemical cross-linking,and a series of products with good biocompatibility,high adhesion and significant antibacterial ability have been prepared.Hydrogel dressings,and preliminary evaluation of its application potential as wound dressings.(1)In this work,gelatin and chitosan were methacrylated modified first,and then compounded with acrylic acid to prepare a gelatin/chitosan/polyacrylic acid composite hydrogel under the catalysis of a photoinitiator.The optimal ratio of hydrogel components was obtained through experiments,and the concentrations of modified gelatin,modified chitosan,and acrylic acid were 2%,2%,and 20%,respectively.The composite hydrogel has good biological adhesion ability,and the adhesion strength can reach 26.31 k Pa.It takes 32 h for the hydrogel to reach swelling equilibrium,and the swelling equilibrium rate is 713%.After 14 days of degradation,the degradation rate is 20.4%.At the same time,the composite hydrogel has good mechanical properties,the maximum compressive strain can reach 73.1%,the compressive modulus can reach 1.1 MPa,and it can still maintain good mechanical ability under the condition of 50 cycles of compression and 60% strain.In addition,the composite hydrogel has obvious inhibitory effects on Escherichia coli and Staphylococcus epidermidis,and the cells can grow and proliferate well on the composite hydrogel,which has the potential to be used as a wound dressing.(2)In this work,tannic acid with antibacterial properties was grafted onto gelatin,and gelTA was cross-linked to form GTT-3 composite hydrogel through mild transglutaminase catalysis.The results of antibacterial experiments showed,GTT-3 hydrogel has good antibacterial activity against Escherichia coli and Staphylococcus epidermidis,and the inhibition rates are 98% and 97% respectively,which are close to the antibacterial effect of cefradine(3.3 mg/m L).In addition,the co-culture of fibroblasts and hydrogel has a survival rate of more than 80%.Red blood cells and pseudopods can be extended on the surface of the gel.It can be seen that the cells can adhere and grow well on the gel.Animal experiments show that the prepared hydrogel can be injected into various organ injuries and quickly form a gel to seal the wound,and at the same time exert a hemostatic effect and promote wound repair.In the mouse hemostasis experiment,compared with the control group,the hemostasis time was reduced by about 25.4%,and the blood loss was reduced by more than 90%.The composite hydrogel obtained by enzymatic cross-linking has good wound repair effects,adhesion properties and antibacterial effects,and has application prospects as wound dressings and adhesives. |
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