Effect of surface wettability on the adsorption of proteins and detergents
Effect of surface wettability on the adsorption of proteins and detergents
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DOI：
10.1021/ja970819l
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发表时间：
1998-04-15
影响因子：
15
通讯作者：
Whitesides, GM
中科院分区：
文献类型：
--
作者：
Sigal, GB;Mrksich, M;Whitesides, GM
本文用表面等离子激元光谱研究了表面润湿性对蛋白质和洗涤剂在金表面自组装单分子膜(SAM)上非特异性吸附的影响。蛋白质和洗涤剂在不带电荷的自组装膜上的吸附一般依赖于表面的润湿性，而润湿性取决于水在环辛烷下与自组装膜的接触角(theta(Co))。自组装膜的润湿性对十二烷基硫酸钠(SDS)吸附的影响取决于是否存在胶束。在临界胶束浓度(CMC)以上，十二烷基硫酸钠只吸附在接触角为cos theta(Co)<；0的表面上(即表面从水到环辛烷的转移具有有利的自由能)。在CMC以下，对吸附的要求要严格得多：十二烷基硫酸钠只吸附在cos theta(Co)<；-0.9的表面上。同样，自组装膜的润湿性对蛋白质吸附的影响也与蛋白质的大小有关。被测试的较小的蛋白质(核糖核酸酶A和溶菌酶)只吸附在被测试的最不潮湿的表面上(cos theta(Co)<；-0.83)。被测试的较大的蛋白质(丙酮酸激酶、纤维蛋白原和丙种球蛋白)在最不润湿的表面上也吸附得最好，但在几乎所有的表面上都有一定程度的吸附；唯一的例外是在表面呈现六(乙二醇基)基团的SAM，没有蛋白质吸附在上面。用洗涤剂将吸附的蛋白质膜从自组装膜上解吸出来。
This report describes the use of surface plasmon spectroscopy to study the effect of surface wettability on the nonspecific adsorption of proteins and detergents to self-assembled monolayers (SAMs) of alkanethiolates on gold. The adsorption of both proteins and detergents to uncharged SAMs showed a general dependence on the wettability of the surface as determined by the contact angle of water on the SAM under cyclooctane (theta(co)). The effect of the wettability of the SAMs on the adsorption of sodium dodecyl sulfate (SDS) was dependent on whether micelles were present. Above the critical micelle concentration (cmc), SDS adsorbed only on surfaces that gave contact angles with values of cos theta(co) < 0 (i.e., the transfer of the surface from water to cyclooctane has a favorable free energy). Below the cmc, the requirement for adsorption was much more stringent: SDS adsorbed only on the surfaces that gave values of cos theta(co) < -0.9. Similarly, the effect of the wettability of the SAMs on the adsorption of proteins showed a dependence on the size of the proteins. The smaller proteins tested (ribonuclease A and lysozyme) adsorbed only on the least wettable surfaces tested (cos theta(co) < -0.83). The larger proteins tested (pyruvate kinase, fibrinogen, and gamma-globulin) also adsorbed best to the least wettable surfaces, but adsorbed to some extent on almost all the surfaces; the single exception was a SAM presenting hexa(ethylene glycol) groups at the surface, to which no protein adsorbed. Films of adsorbed proteins were desorbed from the SAMs by treatment with detergent.