Atthoff Björn, Hilborn Jöns
Polymer Chemistry, Department of Materials Chemistry, Uppsala University, Box 538, 75121 Uppsala, Sweden.
J Biomed Mater Res B Appl Biomater. 2007 Jan;80(1):121-30. doi: 10.1002/jbm.b.30576.
Surface hydrolysis of polyester scaffolds is a convenient technique suggested to promote protein adsorption for improving cell attachment. We have, therefore, investigated the effect of hydrolysis of polyester surfaces for protein adsorption to clarify the conditions needed. Three polyesters, poly(ethylene terephthalate) (PET), poly(lactic acid) (PLA), and poly(glycolic acid) (PGA), were selected. Adsorption was investigated by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and quartz crystal microbalance (QCM). Hydrolyzed PET adsorbed significantly more proteins than nonhydrolyzed. Degradable polymers adsorbed at higher rates when the polymers were hydrolyzed prior to adsorption, but the same amount as nonhydrolyzed, suggesting spontaneous hydrolysis during the adsorption. XPS shows that hydrolysis prior to absorption for PET results in a surface nitrogen composition of approximately 14%, similar to pure protein (16%). Nonhydrolyzed PET surfaces showed only approximately 7% nitrogen, indicating protein layers thinner than approximately 10 nm. Adsorption to PLA and PGA shows nitrogen contents of 14-15% in both cases. SEM revealed striking differences in morphology of the protein coating. Hydrolyzed or spontaneously hydrolyzable surfaces display a pronounced fibrous structure while nonhydrolyzed surfaces give smooth structures. In combination, the results show that surface hydrolysis increase adsorption rate, but not the amount of proteins on polyesters that degrades in vivo. Surface treatment of nondegradable polyester increases the total amount of proteins and induces the formation of fibrous protein structures. Post hydrolysis treatment by acetic acid, replacing the counter-ion to a proton, further enhances protein attachment. Finally, cell attachment experiments verifies that protein adsorption increase the cell attachment to polyester surfaces.
聚酯支架的表面水解是一种简便的技术，旨在促进蛋白质吸附以改善细胞附着。因此，我们研究了聚酯表面水解对蛋白质吸附的影响，以明确所需条件。选择了三种聚酯：聚对苯二甲酸乙二酯（PET）、聚乳酸（PLA）和聚乙醇酸（PGA）。通过X射线光电子能谱（XPS）、扫描电子显微镜（SEM）和石英晶体微天平（QCM）研究吸附情况。水解后的PET比未水解的吸附了显著更多的蛋白质。可降解聚合物在吸附前进行水解时吸附速率更高，但吸附量与未水解时相同，这表明在吸附过程中会发生自发水解。XPS显示，PET在吸附前进行水解会导致表面氮含量约为14%，与纯蛋白质（16%）相似。未水解的PET表面仅显示约7%的氮，表明蛋白质层厚度小于约10纳米。PLA和PGA的吸附情况在两种情况下氮含量均为14 - 15%。SEM揭示了蛋白质涂层形态的显著差异。水解或可自发水解的表面呈现出明显的纤维结构，而未水解的表面则呈现出光滑结构。综合来看，结果表明表面水解提高了吸附速率，但不会增加体内可降解聚酯上的蛋白质吸附量。不可降解聚酯的表面处理增加了蛋白质总量，并诱导形成纤维状蛋白质结构。用乙酸进行水解后处理，将抗衡离子替换为质子，进一步增强了蛋白质附着。最后，细胞附着实验证实蛋白质吸附增加了细胞对聚酯表面的附着。
