Preparation And Hemostatic Properties Of Drug-loaded Polyvinyl Alcohol/Sodium Alginate Composite Hydrogel Dressings

In this paper,polyvinyl alcohol and sodium alginate were selected as the raw materials of hydrogel,and compounded with different mass ratios to form polyvinyl alcohol/sodium alginate composite hydrogel through the cyclic freezing-thawing method.The drug-loaded composite hydrogel loaded with vancomycin hydrochloride was prepared by using this composite hydrogel as a carrier,and its drug release and antibacterial properties were studied.At the same time,polyvinyl alcohol/sodium alginate@VAN composite hydrogel was used to impregnate cotton gauze to prepare drugloaded composite hydrogel dressing.The antibacterial and hemostatic properties of the dressing were studied.The antibacterial and hemostatic properties of the dressing were evaluated through in vitro antibacterial and dynamic coagulation experiments.It is hoped that a dressing with effective hemostatic and antibacterial properties can be prepared through this study.The specific research contents are as follows :(1)Preparation and characterization of polyvinyl alcohol/sodium alginate composite hydrogelPolyvinyl alcohol/sodium alginate composite hydrogel was prepared by physical cross-linking cycle freezing thawing method by compounding polyvinyl alcohol solution with sodium alginate solution in different mass ratios.The effects of different mass ratios on the surface morphology,chemical structure,swelling rate,porosity and mechanical properties were analyzed by SEM,FTIR,swelling rate,porosity and mechanical properties.The test results show that the polyvinyl alcohol/sodium alginate composite hydrogels with different mass ratios have good three-dimensional porous structure.With the increase of the content of sodium alginate with high porosity,the structure gradually becomes loose and the pore size gradually increases,making its porosity gradually increase.At the same time,polyvinyl alcohol/sodium alginate composite hydrogel has good swelling performance,and the swelling rate can reach 940%,which promotes the composite hydrogel to maintain a certain mechanical strength and has good mechanical properties.(2)Drug release and antibacterial properties of polyvinyl alcohol/sodium alginate@VAN composite hydrogelsThe polyvinyl alcohol/sodium alginate@VAN composite hydrogel was prepared with vancomycin hydrochloride as the model drug and polyvinyl alcohol/sodium alginate composite hydrogel as the carrier.The surface morphology,chemical structure and crystallinity of the hydrogels were characterized by SEM,FTIR and XRD.And the drug release and antibacterial properties of polyvinyl alcohol/sodium alginate@VAN composite hydrogels with different mass ratios were studied.The results show that the polyvinyl alcohol/sodium alginate composite hydrogel loaded with vancomycin hydrochloride by physical crosslinking also showed a highly porous three-dimensional network structure,and the reduction of crystallinity proved that vancomycin hydrochloride was successfully loaded on the polyvinyl alcohol/sodium alginate composite hydrogel.Three stages in the release process of the composite hydrogel were observed through drug release experiments : initial burst release,continuous release and entering a stable period.With the increase of the proportion of sodium alginate in the composite hydrogel,the release rate and amount of the drug also increase.The inhibition zone experiment shows that the polyvinyl alcohol/sodium alginate@VAN composite hydrogel shows good antibacterial activity against Staphylococcus aureus,and the bacteria were mainly killed by vancomycin hydrochloride.(3)Preparation and characterization of drug-loaded composite hydrogel dressingsThe cotton gauze was immersed in different mass ratios of polyvinyl alcohol/sodium alginate@VAN composite hydrogel,and crosslinked by freeze-thaw method,and then freeze-dried to prepare a drug-loaded composite hydrogel dressing with a special threedimensional porous structure on the surface.The surface morphology was observed by SEM,and the antibacterial and hemostatic properties of the dressings were studied by in vitro antibacterial test and dynamic coagulation assay.The test results show that the polyvinyl alcohol/sodium alginate@VAN composite hydrogel is uniformly coated on the surface of pure cotton gauze and has a three-dimensional porous structure through SEM.It can be seen from the cross section that the hydrogel enters the interior of cotton gauze structure.Through antibacterial experiments,it can be observed that CG-PS@VAN has a significant bacteriostatic effect on Staphylococcus aureus.The minimum bactericidal concentration is 10 mg/m L,and there is obvious deformation and damage to Staphylococcus aureus.Hemolysis and coagulation tests show that both cotton gauze and CG-PS@VAN have good blood compatibility,and with the increase of the proportion of sodium alginate in the composite hydrogel,the BCI value gradually decreases,the hemostatic performance gradually increases and the more platelets adhere and aggregate on its surface and inside.