| The chitin,as the sixth major element,is widely distributed in the shell of the crustacean,and the cell wall of the fungus and alga.The chitosan is the product of the natural polysaccharide chitin through deacetylation,as the only alkalinity polysaccharide in the nature,it has the unique physicochemical property and biological function and it has been widely applied in the food,medicine and other domains.Compared with the chitosan membrane,the PVA has better film-forming property and mechanical property.Besides,PVA has the following excellent characteristics with good biocompatibility and non-toxicity,but low bioactivity limits its application as biomaterials.According to the advantages and disadvantages of membrane made by chitosan or PVA,a new membrane agent to cure oral ulcer was made by painting the mixed liquor of chitosan from agaricus bisporus and polyving akohol on the ethylcellulose membrane.This bilayer flims have strong antibacterial activity and low cytotoxicity,which is favorable for the healing of the oral ulcer.The research of this paper was as follows.(1)This paper researched on the extraction technology of chitosan from agaricus bisporus chitin.The single factor experiment and orthogonal design was used to determine the optimum process conditions of deacetylation,the results showed that the alkali solution concentration was the main factor which affected the degree of deacetylation,followed by treatment temperature.Under following conditions: reaction time 4h,sodium hydroxide 50%,material proportion 1:40,reaction temperature 95 ?,the degree of deacetylation was up to90%.Furthermore,the analysis of extraction from agaricus bisporus was carried out,the results showed that the infrared spectrum of chitosan from mushroom chitin was consistent with the standard spectrum,all the indexes can meet national food grade standard GB29941-2013.(2)The composite membrane was made up with chitosan from agaricus bisporus,PVA,acetic acid,glycerin,ethyecellulose,tween 20 by vacuum freezing drying technique.The factors and levels of the experiments were determined based on the results of single factor test.According to the design principle of central composite experiment of Box-Benhnkend,the response surface analysis methodology(RSM)was used for optimizing the optimum formula:CS/(PVA+CS)40%,glycerin content 4%,Tween 20 content 1.5%.(3)The thermal capacity analysis of composite films was carried out by using thermal gravity analysis(TGA).We used scanning electron microscopy(SEM)and Fourier transform infrared spectrum(FTIR)to observe the surface of films for further analyzing interfacial adhesion between the chitosan membrane and ethyecellulose membrane.The results showed that the components in the composite membrane have good compatibility,and there is relatively good interface bonding between two layers.(4)Using Escherichia coli and Candida albicans and staphylococcus aureus as the indicator bacteria,the antimicrobial activity of composite membrane was investigated by film-cove ring test,and the in-vitro cytotoxicity test was examined by MTS.To compare the L929 cell cycle using water extract of different materials for flow cytometric.The results showed that this composite membrane had good antibacterial property and low cytotoxicity.The cell cycle of experimental group had no significant difference comparing with the control group.However,further research is needed to see whether the composite membrane has the function of promoting the healing of oral ulceration.In the paper,the double-layer chitosan membrane treating oral ulcer can apply the drugs directly on the ulcer wounds and prolong the effective time of drug effect,which is conductive to increasing treatment effect.The compound membranes have the obvious advantages such as wide membrane materials,simple preparation process,low production cost,mass production,safe usage and have a high application value... |
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