Sofia SJ, Premnath V, Merrill EW
Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139.
Macromolecules. 1998 Jul 28;31(15):5059-70. doi: 10.1021/ma971016l.
Poly(ethylene oxide) (PEO) polymer, in linear and star form, was covalently grafted to silicon surfaces, and the surfaces were tested for their ability to adsorb proteins. Linear PEG of molecular weight 3400, 10 000, and 20 000 g/mol and star PEO molecules were coupled via their terminal hydroxyl groups activated by tresyl chloride to aminosilane-treated silicon wafers. The amount of PEO coupled to the surface was varied by changing the concentration of the tresyl-PEO solution. The dry PEO thickness on the surface was measured using X-ray photoelectron spectroscopy (XPS) and ellipsometry, from which the grafting density was calculated. The PEO surfaces were exposed to solutions of each of three proteins: cytochrome-c, albumin, and fibronectin. The degree of adsorption of each protein was determined by XPS and ellipsometry and recorded as a function of PEO grafting density. All three proteins were found to reach zero adsorption at the highest grafting densities on all three PEG surfaces, which for all three PEG surfaces was a PEO content of 100 +/- 10 ng/cm2. On both star PEO surfaces, albumin and fibronectin decreased to zero adsorption at intermediate values of grafting density, whereas cytochrome-c continued to adsorb at all grafting densities, although with a decreasing trend. A physical model of the surface helped explain these protein adsorption results in terms of the spacing and degree of overlap of grafted PEO chains.
将线性和星型的聚环氧乙烷（PEO）聚合物共价接枝到硅表面，并测试这些表面吸附蛋白质的能力。分子量为3400、10000和20000 g/mol的线性聚乙二醇（PEG）以及星型PEO分子通过经三氟甲磺酸氯活化的末端羟基与氨基硅烷处理过的硅片偶联。通过改变三氟甲磺酸 - PEO溶液的浓度来改变偶联到表面的PEO的量。使用X射线光电子能谱（XPS）和椭偏仪测量表面上干燥的PEO厚度，并据此计算接枝密度。将PEO表面暴露于三种蛋白质（细胞色素c、白蛋白和纤连蛋白）各自的溶液中。通过XPS和椭偏仪测定每种蛋白质的吸附程度，并记录为PEO接枝密度的函数。发现在所有三种PEG表面上，在最高接枝密度下所有三种蛋白质的吸附量均为零，对于所有三种PEG表面而言，该PEO含量为100±10 ng/cm²。在两个星型PEO表面上，白蛋白和纤连蛋白在接枝密度的中间值时吸附量降至零，而细胞色素c在所有接枝密度下均持续吸附，尽管呈下降趋势。表面的物理模型有助于根据接枝的PEO链的间距和重叠程度来解释这些蛋白质吸附结果。
