Preparation And Characterization Of ?-Carrageenan-based Wound Dressing

Hydrogels are three-dimensional,hydrophilic,polymeric networks capable of imbibing large amount of water,and has properties similar to natural extracellular matrix(ECM).Hydrogel have been particularly attractive in wounding healing because it can absorb wound exudates and maintain a moist repair environment to accelerate wound healing.However,the mechanical properties of hydrogel wound dressings are generally poor,and are prone to rupture when subjected to external loads.Some hydrogel wound dressings also cannot block external microorganisms and inhibit the growth of wound bacteria due to the lack of antibacterial activity led to wound infection in the clinical application.In view of the current problems of general hydrogel dressings,this study prepared a new composite hydrogels---BB/HNTs/ ?-carrageenan hydrogel by simple high-temperature mixed dissolution and cooling molding methods.The mechanics,micro-morphology,swelling,water vapor permeability,stability,biocompatibility,blood compatibility and antibacterial properties of composite hydrogel were evaluated.The main research contents and experimental results are as follows:Firstly,three kinds of hydrogels---the KCl / ?-carrageenan hydrogel,glycerin / ?-carrageenan hydrogel and glycerin / KCl / ?-carrageenan hydrogels were prepared by high-temperature mixing and dissolution and cooling molding methods.The characterization of the hydrogels showed that mechanical properties of carrageenan hydrogels were improved significantly by the introduction of KCl,and the maximum compressive breaking strength of hydrogels can be reached to 0.33 Mpa.The KCl / ?-carrageenan hydrogel was the best in mechanical strength when compared with other hydrogels.The microscopic morphology test shows that KCl / ?-carrageenan hydrogel has more uniform penetrating porous structure than that of carrageenan hydrogel without KCl.Secondly,halloysite(HNTs)was introduced to the KCl / ?-carrageenan hydrogel and prepared HNTs / ?-carrageenan composite hydrogel for further enhancing the mechanical strength of the KCl / ?-carrageenan hydrogel and endowing the hydrogel with sustained release drug performance and improving the hydrogel cytocompatibility.The mechanical property evaluation results show that HNTs/?-carrageenan composite hydrogel has better compression resistance than KCl/?-carrageenan hydrogel.The composite hydrogel has more suitable water vapor permeability,can reduce the evaporation of wound moisture and prevent the wound from drying.The evaluation results of cytocompatibility show that HNTs/ ?-carrageenan hydrogel has good biocompatibility and can provide a suitable growth environment for cell adhesion and proliferation.The hemolysis rate of HNTs/ ?-carrageenan composite hydrogel still met the requirement of blood contact materials,although HNTs/?-carrageenan composite hydrogel adsorbed more hemoglobin than the KCl / ?-carrageenan hydrogel.Finally,a broad spectrum antibacterial quaternary ammonium alkaloid---berberine(BB)was introduced to the HNTs/?-carrageenan composite hydrogel and prepared berberine/halloysite/?-carrageenan(BB/HNTs/?-carrageenan)composite hydrogel.The antibacterial properties of the BB/HNTs/?-carrageenan composite hydrogel against E.coli and S.aureus were assessed.The composite hydrogels' mechanical properties,cross-sectional morphology,cytocompatibility,and berberine release performance in vitro was evaluated too.The results show that the composite hydrogel' antibacterial properties was strengthened with the content of berberine increasing.Moreover,the composite didn't cause toxicity to the cells.The berberine exhibits a slower release rate under the action of halloysite which can give the hydrogel a longer-lasting inhibition the fungus.All the results indicated that the BB/HNTs/?-carrageenan composite hydrogel system should have a good application prospect in wound repair materials.