Polyethylene glycol (PEG) coatings have been commonly used in reducing protein adsorption with the intent of improving a biomaterial's biocompatibility. To elucidate the role of PEG surface density in reducing protein adsorption, two types of grafted PEG surface density gradients were evaluated for the adsorption and desorption of albumin and fibrinogen, two blood proteins. PEG density gradients were characterized using contact angle measurements and X-ray photoelectron spectroscopy. Total internal reflection fluorescence was used to measure protein adsorption kinetics and adsorption profiles on the two types of PEG gradients. The PEG gradient generated by the flow method decreased adsorption of both proteins in proportion to the PEG surface density; however, their desorption by buffer solution from the grafted PEG layer was not complete. In contrast, desorption of two proteins from the grafted PEG layer generated by a UV oxidation method resulted in near-zero adsorbed amount. The difference between the two types of gradients might have originated from counter-diffusion of PEG and water molecules occurring during the flow method procedure.

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用于减少蛋白质吸附的聚乙二醇的两个表面梯度

聚乙二醇 (PEG) 涂层通常用于减少蛋白质吸附，目的是提高生物材料的生物相容性。为了阐明 PEG 表面密度在减少蛋白质吸附中的作用，对两种类型的接枝 PEG 表面密度梯度对白蛋白和纤维蛋白原（两种血液蛋白质）的吸附和解吸进行了评估。使用接触角测量和 X 射线光电子能谱表征 PEG 密度梯度。全内反射荧光用于测量两种类型的 PEG 梯度上的蛋白质吸附动力学和吸附曲线。流动法产生的 PEG 梯度与 PEG 表面密度成比例地降低了两种蛋白质的吸附；然而，它们从接枝的 PEG 层被缓冲溶液解吸不完全。相比之下，两种蛋白质从 UV 氧化法产生的接枝 PEG 层解吸导致吸附量接近零。两种类型的梯度之间的差异可能源于流动方法过程中发生的 PEG 和水分子的反向扩散。