Transient effects on microchannel electrokinetic filtering with an ion-permselective membrane
Transient effects on microchannel electrokinetic filtering with an ion-permselective membrane
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DOI：
10.1021/ac7019927
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发表时间：
2008-02-15
影响因子：
7.4
通讯作者：
Tallarek, Ulrich
中科院分区：
文献类型：
--
作者：
Dhopeshwarkar, Rahul;Crooks, Richard M.;Tallarek, Ulrich
描述了混合微流体/纳流体孔网络结构中的电动力学和流体力学及其对带电分析物浓度富集的影响。在微流体通道中光聚合的具有负表面电荷的水凝胶微塞用作纳米多孔膜，并决定相邻微通道隔室内的动电行为。具有双电层厚度量级的平均孔径的纳米多孔水凝胶赋予离子种类的迁移离子选择渗透性（阳离子选择性），其在施加的电场的影响下，驱动两个微通道隔室和基于水凝胶的纳米孔之间的界面附近的本体溶液中的浓度极化。带电分析物的浓缩富集效率取决于这种浓差极化，其强烈影响局部电场强度的分布。此外，设备中的电渗流在确定分析物富集区的位置方面发挥着关键作用。一个理论模型和模拟来解释浓度极化和电渗流的相互作用，相对于所观察到的浓度富集带负电荷的分析物在阴极水凝胶塞微通道溶液界面。
The electrokinetics and hydrodynamics in a hybrid microfluidic/nanofluidic pore network configuration and its effect on the concentration enrichment of charged analytes are described. A hydrogel microplug, photopolymerized in a microfluidic channel, with negative surface charge serves as a nanoporous membrane and dictates the electrokinetic behavior within the adjoining microchannel compartments. The nanoporous hydrogel with a mean pore size on the order of the electrical double layer thickness imparts ion-permselectivity (cation-selectivity) to the migration of ionic species which, under the influence of an applied electrical field, drives concentration polarization in bulk solution near the interfaces between the two microchannel compartments and the hydrogel-based nanopores. The concentration enrichment efficiency for charged analytes depends on this concentration polarization, which strongly affects the distribution of local electrical field strength. In addition, electroosmotic flow in the device plays a critical role in determining the location of the analyte enrichment zone. A theoretical model and simulations are presented to explain the interplay of concentration polarization and electroosmotic flow with respect to the observed concentration enrichment of negatively charged analytes at the cathodic hydrogel plug-microchannel solution interface.