Department of Chemical Engineering, Stanford University, 381 North-South Mall, Stauffer III, Stanford, California 94305-5025, United States.
Langmuir. 2012 Jan 24;28(3):1765-74. doi: 10.1021/la203095p. Epub 2012 Jan 12.
The orientation of a monoclonal, anti-streptavidin human IgG1 antibody on a model hydrophobic, CH(3)-terminated surface (1-dodecanethiol self-assembled monolayer on gold) was studied by monitoring the mechanical coupling between the adsorbed layer and the surface as well as the binding of molecular probes to the antibodies. In this study, the streptavidin antigen was used as a probe for the Fab portions of the antibody, while bacteria-derived Protein G' was used as a probe for the Fc region. Bovine serum albumin (BSA) acted as a blocking protein. Monolayer coverage occurred around 468 ng/cm(2). Below 100 ng/cm(2), antibodies were found to adsorb flat-on, tightly coupled to the surface and unable to capture their antigen, whereas the Fc region was able to bind Protein G'. At half-monolayer coverage, there was a transition in the mechanism of adsorption to allow for vertically oriented antibodies, as evidenced by the binding of both Protein G' and streptavidin as well as looser mechanical coupling with the surface. Monolayer coverage was characterized by a reduced level in probe binding per antibody and an even less rigid coupling to the surface.
研究了单克隆抗链霉亲和素人 IgG1 抗体在模型疏水性 CH(3)-末端表面（金上的 1-十二硫醇自组装单层）上的取向，通过监测吸附层与表面之间的机械偶联以及分子探针与抗体的结合来实现。在这项研究中，链霉亲和素抗原被用作抗体 Fab 部分的探针，而细菌衍生的蛋白 G' 被用作 Fc 区域的探针。牛血清白蛋白（BSA）用作阻断蛋白。单层覆盖率约为 468 ng/cm(2)。在 100 ng/cm(2) 以下，抗体被发现呈平面吸附，与表面紧密结合，无法捕获其抗原，而 Fc 区域能够结合蛋白 G'。在半单层覆盖率时，吸附机制发生转变，允许垂直取向的抗体，这可以通过结合蛋白 G'和链霉亲和素以及与表面的偶联更松弛来证明。单层覆盖率的特点是每个抗体的探针结合水平降低，与表面的偶联也不那么牢固。
