血清白蛋白在多聚阳离子－壳聚糖共混材料表面的构象变化及其与细胞生长的关系

用L-多聚赖氨酸、聚乙烯亚胺及L-多聚鸟氨酸三种多聚阳离子对壳聚糖进行共混修饰,制备了三种共混材料.在这些材料表面吸附了血清白蛋白,并利用圆二色(CD)光谱研究了白蛋白吸附到材料表面后的构象变化.结果显示,与天然状态相比,白蛋白吸附到共混材料表面后,其α-螺旋、β-折叠及无规则卷曲的含量均发生了明显改变.通过研究MC3T3-E1细胞在这些材料表面的生长情况,发现细胞的增殖与血清白蛋白的构象变化有一定关系,在吸附的白蛋白构象与天然构象最接近的共混材料表面,MC3T3-E1细胞增殖水平最高.

The Conformation Changes of Almumin Adsorbed on Polycation-modified Chitosan Materials and The Correlation with Cell Growth

Three polycations, namely poly-L-lysine, polyethyleneimine, and poly-L-ornithine, were blended with chitosan and the corresponding composite materials were produced. On the surfaces of these composite materials, bovine serum albumin was adsorbed and its conformation changes were investigated by circular dichroism (CD) spectrum. The results showed that the secondary structure contents (i.e. α-helix, β-turn, and random coil) of bovine serum albumin adsorbed on material surfaces changed greatly when compared with those of the native state. Then, MC3T3-E1 osteoblast-like cells were cultured on these four materials and the cell proliferation was assayed to explore the correlation between the cell growth and the conformational changes of adsorbed albumin on material surfaces. The results displayed that MC3T3-E1 cells on poly-L-lysine-modified chitosan material, whose surface induced the least alteration in secondary structure of bovine serum albumin, exhibited the best proliferation after 24 and 48 h culture. This study not only provided a feasible method to investigate the conformational changes in the structures of adsorbed proteins on material surfaces, but also presented some useful information for exploring the interaction between cells and chitosan or chitosan-derived materials.