High-Resolution Charge-Based Electrokinetic Separation of Almost Identical Microparticles
High-Resolution Charge-Based Electrokinetic Separation of Almost Identical Microparticles
复制标题
几乎相同的微粒的基于电荷的高分辨率动电分离
DOI：
10.1021/acs.analchem.2c00355
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发表时间：
2022
影响因子：
7.4
通讯作者：
Lapizco-Encinas, Blanca H.
中科院分区：
文献类型：
--
作者：
Vaghef-Koodehi, Alaleh;Dillis, Curran;Lapizco-Encinas, Blanca H.
成熟的技术，例如，色谱法和毛细管电泳可用于分离纳米尺寸的颗粒，例如蛋白质。然而，仍然需要用于分离微米级颗粒的类似技术。基于绝缘体的电动（iEK）系统可以通过结合线性和非线性EK现象实现有效的微粒分离。特别感兴趣的是基于电荷的分离，其可用于分离相似的微生物，例如相同大小、相同属或相同菌株的细菌细胞。几个小组已经报道了微粒的基于电荷的分离，其中微粒之间需要至少40 mV的ζ电位差。目前的工作推动了iEK系统的区分能力的极限，报告了两个相同尺寸（5.1 μm）、相同形状、相同基底材料的微粒的基于电荷的分离，并且颗粒zeta电位的微小差异仅为3.6 mV，这小于先前研究中差异的10%。通过建立一个准确的COMSOL Multiphysics模型，它正确地解释了介电电泳和第二类电泳，可以确定实现这种具有挑战性的分离的条件。此外，COMSOL模型允许预测颗粒保留时间（tR，p），并将其与实验值（tR，e）进行比较。分离结果具有良好的重现性，tR，e的重复性之间的变化仅为9%和11%。这些发现表明，通过遵循一个涉及建模和实验工作的强大协议，可以区分高度相似的粒子，其电荷差异比以前报道的要小得多。
Well-established techniques, e.g., chromatography and capillary electrophoresis, are available for separating nanosized particles, such as proteins. However, similar techniques for separating micron-sized particles are still needed. Insulator-based electrokinetic (iEK) systems can achieve efficient microparticle separations by combining linear and nonlinear EK phenomena. Of particular interest are charge-based separations, which could be employed for separating similar microorganisms, such as bacterial cells of the same size, same genus, or same strain. Several groups have reported charge-based separations of microparticles where a zeta potential difference of at least 40 mV between the microparticles was required. The present work pushes the limit of the discriminatory capabilities of iEK systems by reporting the charged-based separation of two microparticles of the same size (5.1 μm), same shape, same substrate material, and with a small difference in particle zeta potentials of only 3.6 mV, which is less than 10% of the difference in previous studies. By building an accurate COMSOLMultiphysicsmodel, which correctly accounts for dielectrophoresis and electrophoresis of the second kind, it was possible to identify the conditions to achieve this challenging separation. Furthermore, the COMSOL model allowed predicting particle retention times (tR,p) which were compared with experimental values (tR,e). The separations results had excellent reproducibility in terms oftR,ewith variations of only 9% and 11% between repetitions. These findings demonstrate that, by following a robust protocol that involves modeling and experimental work, it is possible to discriminate between highly similar particles, with much smaller differences in electrical charge than previously reported.