Fries Madeleine R, Stopper Daniel, Braun Michal K, Hinderhofer Alexander, Zhang Fajun, Jacobs Robert M J, Skoda Maximilian W A, Hansen-Goos Hendrik, Roth Roland, Schreiber Frank
Institute for Applied Physics, University of Tübingen, 72076 Tübingen, Germany.
Institute for Theoretical Physics, University of Tübingen, 72076 Tübingen, Germany.
Phys Rev Lett. 2017 Dec 1;119(22):228001. doi: 10.1103/PhysRevLett.119.228001.
Protein adsorption at the solid-liquid interface is an important phenomenon that often can be observed as a first step in biological processes. Despite its inherent importance, still relatively little is known about the underlying microscopic mechanisms. Here, using multivalent ions, we demonstrate the control of the interactions and the corresponding adsorption of net-negatively charged proteins (bovine serum albumin) at a solid-liquid interface. This is demonstrated by ellipsometry and corroborated by neutron reflectivity and quartz-crystal microbalance experiments. We show that the reentrant condensation observed within the rich bulk phase behavior of the system featuring a nonmonotonic dependence of the second virial coefficient on salt concentration c_{s} is reflected in an intriguing way in the protein adsorption d(c_{s}) at the interface. Our findings are successfully described and understood by a model of ion-activated patchy interactions within the framework of the classical density functional theory. In addition to the general challenge of connecting bulk and interface behavior, our work has implications for, inter alia, nucleation at interfaces.
蛋白质在固液界面的吸附是一种重要现象，通常可视为生物过程的第一步。尽管其具有内在重要性，但对于潜在的微观机制仍知之甚少。在此，我们利用多价离子展示了对固液界面处带净负电荷蛋白质（牛血清白蛋白）相互作用及相应吸附的控制。这通过椭圆偏振光谱法得以证明，并得到中子反射率和石英晶体微天平实验的证实。我们表明，在系统的富相体相行为中观察到的折返凝聚，其第二维里系数对盐浓度(c_{s})具有非单调依赖性，这以一种有趣的方式反映在界面处蛋白质吸附(d(c_{s}))中。我们的研究结果在经典密度泛函理论框架内通过离子活化斑点相互作用模型得到了成功描述和理解。除了连接体相和界面行为这一普遍挑战外，我们的工作尤其对界面处的成核有影响。
