Study On Preparation And Property Of Carboxymethyl Chitosan-gelatin Membrane

Medical dressing is a kind of materials used to cover wound temporarily. Hyaluronic acid (HA) is a popular new type of biomedical materials, but the total amount of HA is limited, and the price is high. Chitosan is a natural polysaccharide, and the property of its derivatives obtained by chemical modification is similar to HA. It is also found that mix the derivatives of chitosan with other polymer materials like gelatin could produce dressing with improved property .Firstly, carboxymethyl chitosan(CMC) have been obtained via modification of chitosan .The reaction conditions were optimized through orthogonal experiment. Compared with the HA, the optimized product had preferable moisture-absorption , moisture-retention ability and certain antimicrobial activity for S. aureus and E.coli..Secondly, glycerol and solution of CMC and gelatin was mixed at a certain ratio to prepare CMC-gelatin mixed membrane. The concentration of CMC, mass ratio of gelatin and CMC, content of glycerol and temperature had been investigated. Then it was founded that membrane dried at 60℃had good mechanical behavior, the tensile strength of membrane showed a regular change with the increase of the concentration of CMC, mass ratio of gelatin and CMC and the content of glycerol.Thirdly, the CMC-gelatin membrane was crosslinked with 1,4 - butanediol diglycidyl ether to prepare the CMC-gelatin cross-linked membrane, and the reaction conditions were optimized studying the factor of the concentration of CMC, mass ratio of gelatin and CMC, content of glycerol and amount of crosslinking agent. The optimum conditions were as follows: the mass ratio of gelatin and CMC was 2:3, the concentration of CMC was 2%, the amount of crosslinking agent was 40 ul and the content of glycerol was 0.75%. The optimum method was stable and repeatable.Lastly, the property of the cross-linked membrane prepared under the optimum conditions was characterized. The color of dry membrane was slight yellow, the average thickness was 75.6±5.4um, the water-absorption ratio was 180.88±4.90%, the moisture-absorption ratio was 49.74±3.25%, the moisture-retention ratio was 60.62±2.71%, the swelling ratio was 1.67±0.05, the moisture-permeation ratio was 150.67±7.42(g·m^-2·h^-1), the tensile strength was 16.41±1.28MPa, the break elongation ratio was 19.51±0.50%. The membrane was biodegradable and asymmetric which consisted of a dense skin and multilayer three-dimensional structure, and had certain antimicrobial activity for S. aureus and E.coli..