Department of Chemical Engineering , University of California Santa Barbara , Santa Barbara , California 93106 , United States.
Département de Physique, Ecole Normale Supérieure/PSL , Research University , CNRS, 24 rue Lhomond , 75005 Paris , France.
Langmuir. 2019 Dec 3;35(48):15500-15514. doi: 10.1021/acs.langmuir.9b01808. Epub 2019 Aug 9.
Advances in the research of intermolecular and surface interactions result from the development of new and improved measurement techniques and combinations of existing techniques. Here, we present a new miniature version of the surface forces apparatus-the μSFA-that has been designed for ease of use and multimodal capabilities with the retention of the capabilities of other SFA models including accurate measurements of the surface separation distance and physical characterization of dynamic and static physical forces (i.e., normal, shear, and friction) and interactions (e.g., van der Waals, electrostatic, hydrophobic, steric, and biospecific). The small physical size of the μSFA, compared to previous SFA models, makes it portable and suitable for integration into commercially available optical and fluorescence light microscopes, as demonstrated here. The large optical path entry and exit ports make it ideal for concurrent force measurements and spectroscopy studies. Examples of the use of the μSFA in combination with surface plasmon resonance (SPR) and Raman spectroscopy measurements are presented. Because of the short working distance constraints associated with Raman spectroscopy, an interferometric technique was developed and applied to calculate the intersurface separation distance based on Newton's rings. The introduction of the μSFA will mark a transition in SFA usage from primarily physical characterization to concurrent physical characterization with in situ chemical and biological characterization to study interfacial phenomena, including (but not limited to) molecular adsorption, fluid flow dynamics, the determination of surface species and morphology, and (bio)molecular binding kinetics.
分子间和表面相互作用的研究进展源于新的和改进的测量技术的发展以及现有技术的组合。在这里，我们展示了一种新型微型表面力仪——μSFA，它的设计旨在易于使用和具有多种模式功能，同时保留了其他 SFA 模型的功能，包括精确测量表面分离距离以及对动态和静态物理力（即法向力、剪切力和摩擦力）和相互作用（例如范德华力、静电力、疏水力、空间位阻和生物特异性）的物理特性进行表征。与以前的 SFA 模型相比，μSFA 的物理尺寸较小，使其具有便携性，适合集成到商业可用的光学和荧光显微镜中，如这里所示。大的光路进出口使其非常适合进行同时的力测量和光谱学研究。本文展示了μSFA 与表面等离子体共振（SPR）和拉曼光谱测量相结合的应用实例。由于与拉曼光谱相关的短工作距离限制，开发并应用了一种干涉技术来根据牛顿环计算界面分离距离。μSFA 的引入将标志着 SFA 的使用从主要的物理特性表征向原位化学和生物特性表征的转变，以研究界面现象，包括（但不限于）分子吸附、流体流动动力学、表面物种和形态的确定以及（生物）分子结合动力学。
