Ebner Andreas, Kienberger Ferry, Stroh Cordula M, Gruber Hermann J, Hinterdorfer Peter
University of Linz, Institute for Biophysics, 4040 Linz, Austria.
Microsc Res Tech. 2004 Nov;65(4-5):246-51. doi: 10.1002/jemt.20124.
Non-specific adsorption of proteins at solid/liquid interfaces is a major problem in the use of synthetic biomaterials and in ultrasensitive detection methods. Grafting surfaces with a dense layer of poly(ethylene glycol) (PEG) or other polymers is a most widely used strategy to solve this task. While such modified surfaces have been characterized by their ability to resist protein adsorption, the polymer layers themselves have rarely been studied in fine detail. Atomic force microscopy (AFM) using the pulsed force mode (PFM), is an ideal technique to investigate structural features and physiochemical properties of surfaces because topology and adhesion are simultaneously detected with high lateral resolution. In the present study, PFM-AFM was applied to thoroughly characterize different stages of glass derivatization, up to the formation of a dense PEG layer. Lateral inhomogeneities in topology and/or adhesion were observed at all stages before PEG attachment. The covalently bound PEG, however, was seen to form a densely packed monolayer with maximal thickness, smooth surface, and weak adhesion. Thus, PFM-AFM appears to be a valuable tool for the characterization of protein-repelling surfaces in solution.
蛋白质在固/液界面的非特异性吸附是合成生物材料应用和超灵敏检测方法中的一个主要问题。用聚乙二醇（PEG）或其他聚合物的致密层接枝表面是解决这一问题最广泛使用的策略。虽然这种改性表面的特征在于其抵抗蛋白质吸附的能力，但聚合物层本身很少被详细研究。使用脉冲力模式（PFM）的原子力显微镜（AFM）是研究表面结构特征和物理化学性质的理想技术，因为拓扑结构和粘附力可以同时以高横向分辨率检测。在本研究中，PFM-AFM被用于全面表征玻璃衍生化的不同阶段，直至形成致密的PEG层。在PEG附着之前的所有阶段都观察到拓扑结构和/或粘附力的横向不均匀性。然而，共价结合的PEG被认为形成了一个紧密堆积的单分子层，具有最大厚度、光滑表面和弱粘附力。因此，PFM-AFM似乎是表征溶液中蛋白质排斥表面的一种有价值的工具。
