Design and preparation of polymer microcarriers for growth of mouse L cell

研究了微载体表面的静电效应对成纤维细胞生长的影响。制备了各种胺化纤维素珠作为阳离子聚合物微载体。将1，3-二氨基-2-羟基丙烷、聚烯丙胺和聚ε-赖氨酸分别固定在纤维素球上，制备微载体。通过改变固定化条件（胺化时间和温度）来调节微载体的氨基含量。微载体的阴离子交换容量不仅以总氨基含量来估计，而且还以在pH 7.5（细胞培养条件）下的功能性（带电）氨基含量来估计。用常规的细胞培养方法测定小鼠L细胞在各种微载体上的生长时，在pH7.5时，其生长强烈地依赖于微载体的带电荷氨基量，而不一定依赖于它们的总氨基含量。微载体配体的表观pK_a值也显著地控制了氨基的含量。结果表明，在细胞培养条件下，以带电荷氨基含量为0.02- 0.06meq/g的纤维素微球为微载体，小鼠L细胞生长良好，细胞生长的最佳环境受微载体的功能氨基含量控制，而不一定受其引入氨基含量的控制。在pH7.5（细胞培养pH值）条件下，它们的功能氨基含量以带电荷的氨基含量来估算，并且它强烈地受它们的pK <a，app>值的影响。

The electrostatic effect of microcarrier's surface on fibroblastic cell growth was studied. Various aminated cellulose beads were prepared as cationic polymer microcarriers. The microcarriers were prepared by immobilization of 1,3Diamino-2-hydroxypropane, polyallylamine, or poly(ε-lysine), respectively, onto cellulose spherical beads. The amino-group content of the microcarriers was adjusted by changing the immobilization condition(amination time and temperature). The anion-exchange capacities of the microcarriers were estimated not only as total amino- group content but also functional(charged) amino- group content at pH 7.5(cell culture condition). When the growth of mouse L cell on the various microcarriers were determined by common cell culture methods, it strongly depended on the microcarrier's charged amino-group amount at pH 7.5, but not necessarily on their total amino-group content. The charged amino-group content was also drastically controlled by apparent pK_a of the ligand of the microcarriers. As a result, when the cellulose beads with charged amino-group content of 0.02-0.06 meq/g, under cell culture conditions, were used as microcarriers, they showed the excellent growth of mouse L cells.The present results suggest that the optimum environment for the cell growth is controlled by microcarrier's functional amino-group content but not necessarily by their introduced amino-group content. Their functional amino-group contents were estimated as the charged amino-group content at pH 7.5, which is cell culture pH condition, and it is strongly influenced by their pK_<a,app> values originating from the original amines.