Gooch Nathan W, Hlady Vladimir
Department of Bioengineering, University of Utah, Salt Lake City, UT 84112, USA.
Surf Innov. 2015 Sep;3(3):172-180. doi: 10.1680/jsuin.15.00005. Epub 2015 Oct 1.
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.
聚乙二醇（PEG）涂层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，评估了两种类型的接枝PEG表面密度梯度对两种血液蛋白——白蛋白和纤维蛋白原的吸附和解吸情况。通过接触角测量和X射线光电子能谱对PEG密度梯度进行了表征。利用全内反射荧光来测量两种类型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梯度使两种蛋白质的吸附量与PEG表面密度成比例降低；然而，缓冲溶液从接枝PEG层对它们的解吸并不完全。相比之下，紫外线氧化法产生的接枝PEG层上两种蛋白质的解吸导致吸附量接近零。两种梯度类型之间的差异可能源于流动法过程中PEG和水分子的反向扩散。
