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粒径是评价微尺度凝胶载体性能的重要参数。文中以3种不同粒径(202,413,809μm)的海藻酸钙(Ca-Alg)凝胶珠为研究对象,以维生素B_(12)(VB_(12))、牛血清白蛋白(BSA)和壳聚糖(CS)为模型分子,实验考察了胶珠粒径对海藻酸钙/壳聚糖(Ca-Alg/CS)微球性能的影响。采用电子扫描显微镜(SEM)、傅里叶红外光谱仪(FTIR)和激光共聚焦显微镜(CLSM)等方法表征膜结构与形貌,采用膨胀率表征膜稳定性。结果表明:Ca-Alg/CS微球的凝胶结构、分子扩散性能和聚电解质复合膜性能与Ca-Alg胶珠粒径具有相关性。随着胶珠粒径减小,凝胶结构趋于致密,对分子扩散阻力增大。在成膜反应过程中,小粒径胶珠表面为成膜反应提供了更多的反应交联位点,在胶珠表面形成更致密连续和更厚的聚电解质复合膜。Ca-Alg/CS微球具有优异的膜强度和稳定性,在细胞固定化培养中具有显著应用优势。
Particle size is an important parameter for evaluating the performance of micro-scale gel supports. Three kinds of Ca-Alg gel beads with different particle sizes (202,413,809μm) were selected as experimental materials. Vitamin B 12 (VB 12), bovine serum albumin (BSA) (CS) as model molecules, the effects of the size of the beads on the properties of calcium alginate / chitosan (Ca-Alg / CS) microspheres were investigated experimentally. The structure and morphology of the membrane were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and confocal laser scanning microscopy (CLSM). The swelling rate was used to characterize the membrane stability. The results show that the gel structure, molecular diffusion and polyelectrolyte composite membrane properties of Ca-Alg / CS microspheres are correlated with the particle size of Ca-Alg. With the decrease of the size of the gel beads, the gel structure tends to be dense and the resistance to molecular diffusion increases. During the film-forming reaction, the surface of the small particle size bead provides more reactive cross-linking sites for the film forming reaction and forms a denser continuous and thicker polyelectrolyte composite film on the bead surface. Ca-Alg / CS microspheres have excellent membrane strength and stability and have significant application advantages in cell-immobilized culture.