Construction Of EGF And CeO₂ Loaded Bletilla Striata Polysaccharide/PLGA Core-shell Fiber Scaffold And Its Effect On Wound Healing

Bletilla striata polysaccharide（BSP）has excellent wound healing properties.In order to expand its application in skin wound dressing,the research group used emulsion electrospinning to load different concentrations of BSP into PLGA core and prepare BSP/PLGA emulsion electrospinning fibrous scaffolds.The emulsion phase was observed by inverted phase contrast microscope,and the best technological conditions of spinning emulsion preparation were investigated.The fiber morphology was observed by field emission scanning electron microscope（SEM）.The core shell structure was observed by transmission electron microscope（TEM）and confocal laser scanning microscope（CLSM）,and the composition of fiber scaffold was characterized by near-infrared diffuse reflectance spectroscopy.The hydrophilicity of BSP/PLGA scaffolds was measured by water contact angle.The water absorption and moisture retention of the scaffolds were characterized by gravimetric method.The content of BSP in the scaffolds was determined by ultraviolet spectrophotometry.The full-thickness skin injury model of rats was established to investigate the acute wound healing performance of BSP/PLGA scaffolds.EGF and nano-CeO₂ were added in the aqueous phase to complete the drug loading,preparation EGF@BSP-CeO₂/PLGA（EBCP）.The drug loading and entrapment efficiency of EGF were determined by UV spectrophotometry.The ultraviolet absorption properties of the scaffolds were characterized by full wavelength scanning.The mechanical properties of the scaffolds were determined by tensile test with universal testing machine.The degradation characteristics of the scaffolds were investigated by gravimetric method,The permeability of the scaffolds was measured by vacuum method.The water absorption of the scaffolds was measured by gravimetric method.The antioxidant activity of EBCP was evaluated by free radical scavenging test in vitro.The antibacterial activity of EBCP was tested by co-incubation dilution coating plate method in vitro.The biocompatibility of EBCP was characterized by blood compatibility test.The hemostatic activity of EBCP was evaluated by mouse liver hemorrhage model,Objective to investigate the effect of EBCP on acute skin healing in mice.The results showed that more than 80%of BSP was successfully loaded into PLGA fiber core,the average diameter of BSP/PLGA fibrous scaffold was about 300-340nm,and the thickness was about 100μm.The water contact angle of PLGA fibrous scaffold is 120.6 degrees,and the minimum water contact angle of BSP/PLGA fibrous scaffold is 34.2 degrees,which proves that the loading of BSP makes PLGA fiber have good hydrophilicity,which makes BSP/PLGA fibrous scaffold have good water absorption.The results of full-thickness skin repair experiment in rats showed that the BSP/PLGA fibrous scaffold had excellent wound healing promoting performance,and the scaffold with the highest content of BSP had the best wound healing promoting performance.The drug loaded fibrous scaffold EBCP was prepared by adding EGF and nano-CeO₂into its core,with full shape,uniform diameter,good air permeability,mechanical properties and excellent mechanical properties The results of blood compatibility test showed that the hemolysis rate of EBCP was less than 5%,indicating that it had good biocompatibility.The results of mouse liver hemorrhage model showed that EBCP had good hemostatic performance,The results of the repair experiment of infected skin injury in mice showed that EBCP had excellent effect on promoting wound healing.