Preliminary Study Of Bacterial Cellulose Modified Membrane Used In Wound Dressings

This thesis focuses on the applications of bacterial cellulose and its modified membranes in medical dressings.In our study,bacterial cellulose was biosynthesized by incubating Acetobacter xylinum NUST4.2 in the culture medium and modified bacterial cellulose membranes were prepared by adding water-soluble polymers in the culture medium of Acetobacter xylinum NUST4.2.Then,as medical dressing materials, bacterial cellulose and modified bacterial cellulose were evaluated in the laboratory for its physical properties.In the first part,bacterial cellulose was prepared,characterized and evaluated.First, bacterial cellulose gel was obtained by Acetobacter xylinum NUST4.2 in the culture medium.Then,bacterial cellulose film and bacterial cellulose foam were prepared by heat-drying and freeze-drying system,respectively.Furthermore,the moisture absorption,porosity,water vapor permeability and anti-tensile properties were tested. The results showed that the BC-Foam not only has good moisture absorption,porosity and moisture permeability,but also has certain anti-tensile strength.In the second part,modified bacterial cellulose were prepared,characterized and evaluated.First of all,four kinds of modified bacterial cellulose,including carboxymethylated-bacterial cellulose,sodium alginate/bacterial cellulose, chitosan/bacterial cellulose and aloe polysaccharide/bacterial cellulose were prepared by adding carboxymethylated cellulose,sodium alginate,chitosan and aloe polysaccharide in the culture medium of Acetobacter xylinum NUST4.2.Then,they were characterized by infrared spectroscopy(IR) and scanning electron microscope (SEM).The IR tests showed the existence of carboxy group in carboxymethylated-bacterial cellulose and sodium alginate/bacterial cellulose,amino group in chitosan/bacterial cellulose and carbonyl group in aloe polysaccharide/bacterial cellulose.The results of SEM exhibited the significant changes in the mesh structure and filaments of the modified films,which proved the success of the modification on the bacterial cellulose.In that situation, carboxymethylated-bacterial cellulose film,sodium alginate/bacterial cellulose film, chitosan/bacterial cellulose film,aloe polysaccharide/bacterial cellulose film and carboxymethylated-bacterial cellulose foam,sodium alginate/bacterial cellulose foam, chitosan/bacterial cellulose foam,aloe polysaccharide/bacterial cellulose foam by heat-drying and freeze-drying system,respectively.Furthermore,the moisture absorption,porosity,water vapor permeability and anti-tensile strength properties of them were tested.The results showed that four kinds of modified bacterial cellulose foams not only has good moisture absorption,porosity and moisture permeability,but also has certain anti-tensile strength compared with its corresponding modified bacterial cellulose films,so they have potential use in medical dressings.Compared with the bacterial cellulose foam,carboxymethylated-bacterial cellulose foam and sodium alginate/bacterial cellulose foam have better moisture absorption and anti-tensile strength,aloe polysaccharide/bacterial cellulose foam have better anti-tensile strength while chitosan/bacterial cellulose foam displayed similar properties with bacterial cellulose foam but a little declination in anti-tensile strength, which suggested that carboxymethylated-bacterial cellulose foam,sodium alginate/bacterial cellulose foam and aloe polysaccharide/bacterial cellulose foam can be more widely applied in the trauma treatment.Chitosan/bacterial cellulose foam shows better biological performance than bacterial cellulose foam and still maintains good physical properties as bacterial cellulose foam.