Department of Medicine, Univesity of Louisville, 550 South Jackson Street, Louisville, Kentucky 40292, USA.
J Biomed Mater Res A. 2010 May;93(2):537-46. doi: 10.1002/jbm.a.32561.
Protein adsorption onto the surface of a biomaterial mediates cell adhesion and enhances tissue-implant integration. In a previous study, we demonstrated that crystallization of bioactive glass (BG) significantly increased the negative zeta potential and decreased serum protein adsorption onto the material surface. In this study, the conformation of protein adsorbed onto the surface of amorphous bioactive glass (ABG) and crystallized bioactive glass (CBG) was analyzed and correlated to bone marrow mesenchymal stem cell adhesion and spreading. ABG and CBG were immersed in three different protein solutions containing 10% fetal bovine serum, bovine serum albumin (BSA), and fibronectin (FN) for 4 h at 37 degrees C. Grazing angle Fourier transform infrared spectroscopy (GA-FTIR) demonstrated that the ratio of (amide I)/(amide II) functional groups of all proteins adsorbed onto ABG was greater than that for proteins adsorbed onto CBG. The Gaussian curve fitting analysis suggests that the significant expression of amide I, rich in charged and flexible unordered secondary structure of adsorbed FN, stimulated bone cell adhesion and spreading on the surface of ABG. CBG enforces protein conformation that exposes amide II, rich in neutral and stable beta-sheet structure and alpha-helix, which limited cell adhesion and spreading. Although ABG adsorbed significantly higher quantity of BSA than FN, GA-FTIR analyses showed that the ratio of amide I/amide II was significantly higher for adsorbed FN. Therefore, the intensity of amide I or amide II bands cannot be taken as a measure of the quantity of adsorbed protein.
蛋白质在生物材料表面的吸附介导细胞黏附，并增强组织-植入物的整合。在之前的研究中，我们证明了生物活性玻璃（BG）的结晶显著增加了负 zeta 电位，并减少了材料表面对血清蛋白的吸附。在这项研究中，分析了吸附在无定形生物活性玻璃（ABG）和结晶生物活性玻璃（CBG）表面的蛋白质的构象，并将其与骨髓间充质干细胞的黏附和铺展相关联。ABG 和 CBG 分别浸泡在含有 10%胎牛血清、牛血清白蛋白（BSA）和纤连蛋白（FN）的三种不同蛋白质溶液中 4 小时，温度为 37 摄氏度。掠角傅里叶变换红外光谱（GA-FTIR）表明，所有吸附在 ABG 上的蛋白质的（酰胺 I）/（酰胺 II）官能团的比例大于吸附在 CBG 上的蛋白质。高斯曲线拟合分析表明，富含带电荷和柔性无规二级结构的吸附 FN 的酰胺 I 的显著表达，刺激了细胞在 ABG 表面的黏附和铺展。CBG 迫使蛋白质构象暴露酰胺 II，富含中性和稳定的β-折叠结构和α-螺旋，这限制了细胞的黏附和铺展。尽管 ABG 吸附的 BSA 量明显高于 FN，但 GA-FTIR 分析表明，吸附 FN 的酰胺 I/酰胺 II 比例明显更高。因此，酰胺 I 或酰胺 II 带的强度不能作为吸附蛋白量的衡量标准。
