Microscale Bioseparations Laboratory, Biomedical Engineering Department, Rochester Institute of Technology, 160 Lomb Memorial Drive, Rochester, NY 14623, USA.
Biosensors (Basel). 2024 Feb 22;14(3):119. doi: 10.3390/bios14030119.
Analyte migration order is a major aspect in all migration-based analytical separations methods. Presented here is the manipulation of the migration order of microparticles in an insulator-based electrokinetic separation. Three distinct particle mixtures were studied: a binary mixture of particles with similar electrical charge and different sizes, and two tertiary mixtures of particles of distinct sizes. Each one of the particle mixtures was separated twice, the first separation was performed under low voltage (linear electrokinetic regime) and the second separation was performed under high voltage (nonlinear electrokinetic regime). Linear electrophoresis, which discriminates particles by charge, is the dominant electrokinetic effect in the linear regime; while nonlinear electrophoresis, which discriminates particles by size and shape, is the dominant electrokinetic effect in the nonlinear regime. The separation results obtained with the three particle mixtures illustrated that particle elution order can be changed by switching from the linear electrokinetic regime to the nonlinear electrokinetic regime. Also, in all cases, better separation performances in terms of separation resolution () were obtained by employing the nonlinear electrokinetic regime allowing nonlinear electrophoresis to be the discriminatory electrokinetic mechanism. These findings could be applied to analyze complex samples containing bioparticles of interest within the micron size range. This is the first report where particle elution order is altered in an iEK system.
分析物的迁移顺序是所有基于迁移的分析分离方法的一个主要方面。本文介绍了基于绝缘体的电动分离中对微粒迁移顺序的操控。研究了三种不同的颗粒混合物：具有相似电荷但大小不同的颗粒的二元混合物，以及三种具有不同尺寸的颗粒的三元混合物。每个颗粒混合物都进行了两次分离，第一次分离在低电压下进行（线性电动分离），第二次分离在高电压下进行（非线性电动分离）。线性电泳通过电荷对颗粒进行区分，是线性区中的主要电动效应；而非线性电泳通过大小和形状对颗粒进行区分，是非线性区中的主要电动效应。对三种颗粒混合物的分离结果表明，通过从线性电动分离切换到非线性电动分离，可以改变颗粒的洗脱顺序。此外，在所有情况下，通过采用非线性电动分离来实现非线性电泳的区分电动机制，可以获得更好的分离性能，以分离分辨率（）来衡量。这些发现可应用于分析含有微米范围内生物颗粒的复杂样品。这是首次在 iEK 系统中改变颗粒洗脱顺序的报告。
