壳聚糖溶液pH对载细胞海藻酸钠-壳聚糖微胶囊性能的影响

以激光共聚焦扫描显微镜为研究手段, 原位直观地考察了在不同pH条件下聚电解质膜的络合程度和蛋白扩散情况. 通过分析pH值对微胶囊膜性能的影响规律, 并结合不同种类细胞对环境pH的敏感特性, 确定了制备细胞培养用海藻酸钠-壳聚糖微胶囊的最佳pH值. 结果表明, 当壳聚糖溶液的pH值由3.50增加到6.50, 微胶囊膜的络合深度呈现高-低-高的趋势, 而微胶囊膜的膨胀性能呈现低-高-低的趋势, 模型蛋白通过微囊膜的扩散呈现低-高-低的趋势, 拐点均出现在pH=4.00和5.50处. 结合动物细胞及微生物细胞对环境pH耐受能力的考察, 确定制备微囊化动物细胞时, 微胶囊成膜反应溶液的最佳pH值为5.50; 制备微囊化大肠杆菌时, 反应溶液的最佳pH值为5.00; 制备微囊化酵母菌时, 反应溶液的最佳pH值为4.50.

Effect of pH of Chitosan Solution on Properties of Sodium Alginate-Chitosan Microcapsules with Cells

Sodium alginate-chitosan(AC) microcapsules are often used as the immobilization carriers for cell culture.They are composed of porous gel as the core facilitating cell adhesion,and coated with polyelectrolyte complex membrane protecting cells and allowing selective mass transfer.Therefore,the regulation and control of membrane properties can directly affect the growth and metabolism of cells in microcapsules.Among many parameters,pH of chitosan solution is the important one.In this paper,the formation of polyelectrolyte membrane,the degree of complex formation and protein diffusion at different pH values were directly observed in situ by using a confocal laser scanning microscope(CLSM).The effect of pH on the properties of AC microcapsule membrane was discussed.The optimal pH was determined in the preparation of AC microcapsules with different cells(animal and microbial cells).It was demonstrated that the membrane thickness showed "high-low-high" shape,the swelling behavior of microcapsules "low-high-low" shape and the protein diffusion across the membrane "low-high-low" shape as a function of pH,the inflection points all appeared at pH=4.00 and 5.50.Combining with the sensitivity experiment of different kinds of cells to environment pH,it was suggested that the optimal pH of chitosan solution for AC microencapsulated animal cells was 5.50,AC microencapsulated E. coli cells 5.00,and AC microencapsulated yeast cells such as saccharomyces cerevisiae(S.cere.) 4.50,respectively.