氧气在微胶囊膜中的扩散行为将直接决定微囊内细胞的生长代谢行为.以海藻酸钠-壳聚糖聚电解质复合平板膜为研究模型,利用渗透池法,重点考察溶氧在膜中的扩散行为及其影响因素.结果显示:复合膜的扩散系数和孔隙率均低于海藻酸钙,复合膜中溶氧扩散系数为(7～13)×10-10m2·s-1,为水中的23.3％～43.3％,孔隙率为93％～97％;扩散系数随海藻酸钠特性黏度的增大而减小,随壳聚糖分子量的增大而减小.微胶囊膜是氧传质主要的阻力部位,孔隙率、三维结构和材料极性是影响扩散性能的重要因素,改变海藻酸钠特性黏度和壳聚糖分子量可以改变膜孔隙率、结构和材料极性,进而调节膜扩散性能.%The oxygen diffusible property of the microcapsule affects the proliferation and metabolism of cells -cultured within the microcapsules. In this study, the effective diffusion coefficient De of dissolved oxygen in the alginate/chitosan (AC) microcapsule membrane was investigated, and the alginate-chitosan polyelectrolyte complex (PEC) film was used as the investigated model of the membrane. The De of the film was measured by a diffusion cell. It was found that both the De and the void fraction of the PEC film are smaller than those of calcium alginate gel. The De of the PEC film varies between 7×10-10m-3s-1 and 13×10-10m-2s-1, which are equivalent to 23.3%~43.3% of the oxygen diffusivity in water, and the void fraction of the membrane which was expressed as volume fraction of water in the membrane is 93%~97%. The De of the PEC film decreases with the increase of the intrinsic viscosity of alginate and the molecular weight of the chitosan which form the PEC film. It was also found that the microcapsule membrane is the main diffusion resistance for the oxygen diffusion, and the diffusion performance of the membrane can be affected by the void fraction of the PEC membrane, the structure of gel and the polarity of the polymer which are determined by the intrinsic viscosity of the alginate and the molecular weight of the chitosan.
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