Preparation And Evaluation Of Bletilla Striata Polysaccharide/Chitosan Composite Membrane And Bilayer Membrane

Wound dressings have the role of protecting the wound,accelerating hemostasis and promoting wound healing.Although traditional dressings such as gauze,absorbent cotton and bandages can provide some protection to the trauma,they cannot improve the moist healing environment for the trauma,poor patient compliance and little retention of moist environment and granulation tissue can easily enter the dressing mesh causing secondary injury.Therefore,there is an increasing interest in trauma dressings prepared from biomass materials.The objective of this research is to produce new biodegradable antioxidants and antimicrobial films based on two natural polysaccharides,Bletilla striata polysaccharide(BSP)and chitosan(CS).Chitosan has been widely used in wound dressings because of its excellent film-forming properties,biocompatibility,non-toxicity,antibacterial and hemostatic properties.However,it has relatively low mechanical properties,BSP has the advantages of non-toxicity,degradability,and antioxidant activity.Therefore,the objective of this research is to produce new biodegradable,antibacterial and antioxidant films based on two natural polysaccharides,BSP and CS.The membranes were characterized by SEM,IR,NMR,and XRD to investigate the surface and internal structure,and TG analysis was performed to investigate the thermal properties of the films.The physical properties of the membranes were also evidently improved after the introduction of BSP.The biological activity of the prepared membranes was evaluated by antioxidant and antibacterial assays to be used as a potential wound dressing for further study.The content of this experiment includes the following parts:1)The tubers of Bletilla striata were crushed,then defatted,hydroextracted,deproteinized and alcoholized in turn to obtain crude polysaccharide.2)The composite membranes BC1,BC2 and BC3 were prepared by changing the mass ratio of BSP to CS to 75:25,50:50 and 25:75,respectively,by a series of mixed membranes and bilayer of different ratios made from BSP solution and CS solution by casting method.3)Characterization of its physicochemical properties by scanning electron microscopy,infrared spectroscopy,nuclear magnetic resonance,X-ray diffractometry,thermogravimetric analysis and swelling properties and mechanical properties tests.4)Biocompatibility was evaluated by in vitro cytotoxicity assay(CCK-8 method)and degradation test.5)The antibacterial activity of the composite and bilayer membranes was evaluated by in vitro antibacterial tests(S.aureus,E.coli,P.aeruginosa).The experimental results showed that the prepared films were characterized by SEM,FTIR,NMR and X-ray diffraction to examine the surface morphology and internal structure,while thermogravimetric analysis was used to explore the thermal properties of the films.The physical properties of the films were also significantly improved by the incorporation of BSP.The bioactivity of the prepared films was evaluated by antioxidant and antimicrobial assays for further studies as potential wound dressings.The prepared films showed good cell viability,biocompatibility and non-toxicity by CCK-8 method analysis.These studies suggest that BSP / CS films can be used as suitable materials for the development of biomaterial matrices in novel wound dressings.