School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287-1604, United States.
Anal Chem. 2021 Jan 26;93(3):1352-1359. doi: 10.1021/acs.analchem.0c02763. Epub 2020 Dec 21.
Proteins are perhaps the most important yet frustratingly complicated and difficult class of compounds to analyze, manipulate, and use. One very attractive option to characterize and differentially concentrate proteins is dielectrophoresis, but according to accepted theory, the force on smaller particles the size of proteins is too low to overcome diffusive action. Here, three model proteins, immunoglobulin G, α-chymotrypsinogen A, and lysozyme, are shown to generate forces much larger than predicted by established theory are more consistent with new theoretical constructs, which include the dipole moment and interfacial polarizability. The forces exerted on the proteins are quantitatively measured against well-established electrophoretic and diffusive processes and differ for each. These forces are orders of magnitude larger than previously predicted and enable the selective isolation and concentration of proteins consistent with an extremely high-resolution separation and concentration system based on the higher-order electric properties. The separations occur over a small footprint, happen quickly, and can be made in series or parallel (and in any order) on simple devices.
蛋白质可能是最重要的，但令人沮丧的是，它们是最复杂和最难分析、操作和使用的化合物之一。一种非常有吸引力的蛋白质分析和差异化浓缩的方法是介电泳，但是根据公认的理论，对于蛋白质大小的较小颗粒，作用力太低，无法克服扩散作用。在这里，三种模型蛋白，免疫球蛋白 G、α-糜蛋白酶原 A 和溶菌酶，产生的力比既定理论预测的要大得多，更符合包括偶极矩和界面极化率在内的新理论结构。这些蛋白所受的力与已建立的电泳和扩散过程进行了定量测量，并且每种蛋白的力都有所不同。这些力比之前预测的要大几个数量级，使蛋白质的选择性分离和浓缩成为可能，从而实现基于更高阶电特性的超高分辨率分离和浓缩系统。这些分离发生在一个小的区域内，速度很快，可以在简单的设备上串联或并联（并且可以任意顺序）进行。
