以海藻酸钠-壳聚糖微胶囊(AC微胶囊)为研究对象,以酵母细胞S.cerevisiae BY4741为细胞模型,分别考察了相同成膜反应时间和相同成膜厚度两种情况下,壳聚糖分子量对微囊膜膨胀行为、微囊内细胞增殖情况及微囊化细胞培养过程中细胞泄漏的影响规律.研究结果显示,在成膜反应时间相同的情况下,壳聚糖分子量越小,向海藻酸钙凝胶网络扩散越容易,交联成膜越厚,微胶囊膜越能耐受渗透压膨胀.但在控制相同膜厚的情况下,大分子量壳聚糖由于分子链长,与凝胶微球表面海藻酸钠分子的作用位点多,易纠结相邻海藻酸钠分子链形成更致密的络合交联,呈现更高的耐受渗透压膨胀的特性.AC微囊化细胞培养48 h后,小分子量壳聚糖充分成膜反应制备的AC微胶囊,虽然膨胀不显著,但由于膜结构占据了更多微胶囊体积,既缩小了酵母细胞的增殖空间,又极大增加了传质阻力,反而限制了细胞增殖.培养过程中,各组微胶囊均未发现明显的细胞泄漏现象.%Alginate-chitosan (AC) microencapsulated cell culture was carried out with S. cerevisiae BY4741 (yeast cells) as cell model. By controlling the same membrane formation time or the same membrane thickness of AC microcapsules, the effects of chitosan molecular weight (Mw) on membrane swelling behavior, microencapsulated cell growth and cell leakage from microcapsules were investigated. When keeping the same membrane formation time, the smaller the chitosan Mw, the easier the molecules diffusing into alginate network, resulting in thicker membrane with the ability of resisting swelling. However, when keeping the same membrane thickness, chitosan with larger Mw could provide more binding sites on the surface of alginate network, resulting in more compact membrane with the ability of resisting swelling. Furthermore, all kinds of AC microencapsulated ceils prepared with different chitosan Mw by keeping the same membrane formation time and membrane thickness were cultured for 48 h. The growth dynamics of AC microencapsulated yeast cells were investigated. It showed that AC microcapsules preparedwith smaller chitosan Mw at sufficient membrane formation time demonstrated higher membrane strength,but the cell growth was lower due to the thicker membrane that occupied more space of microcapsules andincreased transfer resistance. It was also noticed that there was almost no ceils leakage during the processof microencapsulated cell culture in all experiments.
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