writer：Jing Jin, Yuanyuan Han, Chang Zhang, Jingchuan Liu, Wei Jiang, Jinghua Yin, Haojun Liang
keywords：蛋白质吸附, 双偏振干涉, 石英晶体微天平, 牛血清白蛋白, 溶菌酶, PEG构象
source：期刊
specific source：Colloids and Surfaces B: Biointerfaces, 2015, 136, 838-844
Issue time：2015年

摘要：利用双偏振干涉技术（DPI）和带耗散功能的石英晶体微天平（QCM-D）研究了牛血清白蛋白（BSA）和溶菌酶（LYZ）在聚乙二醇（PEG）层上的吸附行为，以阐明蛋白质吸附机理。DPI分析表明，PEG2000和PEG5000分别呈紧密和疏松的蘑菇状构象；少量LYZ可通过氢键吸引置换紧密蘑菇状PEG2000链周围的部分界面水，导致蛋白质吸附。疏松蘑菇状PEG5000链具有更柔顺的构象和较高的弹性排斥能，可阻止所有BSA和大部分LYZ的吸附。QCM分析表明，PEG2000和PEG5000呈紧密和伸展的刷状构象；LYZ吸附质量存在临界接枝密度区域，PEG2000约为0.19链/nm2，PEG5000约为0.16链/nm2。当PEG接枝密度高于临界区域（刷状构象）时，PEG与LYZ之间的氢键吸引占主导；当接枝密度低于临界区域（蘑菇状构象）时，PEG链的高构象熵驱动的弹性排斥是PEG-蛋白质体系中位阻排斥的主要作用力。因此，BSA的吸附被PEG链的高弹性排斥能抑制，而LYZ的吸附由熵弹性排斥与氢键吸引之间的相互作用平衡。

Abstract：In this study, elucidation of protein adsorption mechanism is performed using dual polarization interferometry (DPI) and quartz crystal microbalance with dissipation (QCM-D) to study adsorption behaviors of bovine serum albumin (BSA) and lysozyme (LYZ) on poly(ethylene glycol) (PEG) layers. From the analysis of DPI, PEG2000 and PEG5000 show tight and loose mushroom conformations, respectively. Small amount of LYZ could displace the interfacial water surrounding the tight mushroomed PEG2000 chains by hydrogen bond attraction, leading to protein adsorption. The loose mushroomed PEG5000 chains exhibit a more flexible conformation and high elastic repulsion energy that could prevent protein adsorption of all BSA and most of LYZ. From the analysis of QCM, PEG2000 and PEG5000 show tight and extended brush conformations. The LYZ adsorbed mass has critical regions of PEG2000 (0.19 chain/nm2) and PEG5000 (0.16 chain/nm2) graft density. When graft density of PEG is higher than the critical region (brush conformations), the attraction of hydrogen bonds between PEG and LYZ is the dominant factor. When graft density of PEG is lower than the critical region (mushroom conformations), elastic repulsion between PEG and proteins is driven by the high conformation entropy of PEG chains, which is the dominant force of steric repulsion in PEG-protein systems. Therefore, the adsorption of BSA is suppressed by the high elastic repulsion energy of PEG chains, whereas the adsorption of LYZ is balanced by the interactions between the repulsion of entropy elasticity and the attraction of hydrogen bonds.

论文链接：https://doi.org/10.1016/j.colsurfb.2015.10.025