Vaghef-Koodehi Alaleh, Lapizco-Encinas Blanca H
Microscale Bioseparations Laboratory and Biomedical Engineering Department, Rochester Institute of Technology, 160 Lomb Memorial Drive, Rochester, New York 14623, United States.
Anal Chem. 2025 May 20;97(19):10433-10441. doi: 10.1021/acs.analchem.5c01262. Epub 2025 May 8.
Traditional analytical methods such as electrophoresis and chromatography have long been employed for separating bioparticles, particularly nanosized analytes. However, the efficient separation of micrometer-sized biological particles remains a challenge. Electrokinetic (EK) systems, particularly insulator-based EK (iEK) platforms, offer promising solutions by leveraging both linear and nonlinear electrokinetic phenomena to manipulate analyte migration and separation. A key approach in analyte separations is the reversal of migration order, which has been extensively studied for small molecules but remains underexplored for biological cells. This study investigates the reversal of migration order for the separation of two strains of () (ATCC 9763 and ATCC 9080) cells using an iEK system under a DC voltage. A COMSOL model was employed to simulate the system and optimize the separation conditions. Then, experimental separations were conducted under both linear and nonlinear EK regimes, where the applied voltage was allowed to control the separation mechanism: size-based or charge-based. The results demonstrated that switching from a charge-based separation under a linear EK regime to a size-based separation under a nonlinear regime successfully reversed the migration order of cells, enhancing separation resolution. These findings highlight the potential of iEK systems for tunable separations of micrometer-sized biological analytes and provide a foundation for further applications in biological and clinical diagnostics.
诸如电泳和色谱法等传统分析方法长期以来一直用于分离生物颗粒，尤其是纳米级分析物。然而，微米级生物颗粒的高效分离仍然是一项挑战。电动（EK）系统，特别是基于绝缘体的EK（iEK）平台，通过利用线性和非线性电动现象来操纵分析物的迁移和分离，提供了有前景的解决方案。分析物分离中的一个关键方法是迁移顺序的反转，这对于小分子已经进行了广泛研究，但对于生物细胞仍然研究不足。本研究调查了在直流电压下使用iEK系统分离两株（）（美国典型培养物保藏中心9763和美国典型培养物保藏中心9080）细胞时迁移顺序的反转。采用COMSOL模型对系统进行模拟并优化分离条件。然后，在线性和非线性EK模式下进行实验分离，其中施加的电压用于控制分离机制：基于尺寸或基于电荷。结果表明，从线性EK模式下基于电荷的分离切换到非线性模式下基于尺寸的分离成功地反转了细胞的迁移顺序，提高了分离分辨率。这些发现突出了iEK系统在微米级生物分析物可调谐分离方面的潜力，并为在生物和临床诊断中的进一步应用奠定了基础。
