Electrokinetic particle translocation through a nanopore
Electrokinetic particle translocation through a nanopore
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DOI：
10.1039/c0cp02267e
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发表时间：
2011-01-01
影响因子：
3.3
通讯作者：
Qian, Shizhi
中科院分区：
文献类型：
--
作者：
Ai, Ye;Qian, Shizhi
通过单个纳米孔的纳米粒子电泳移位诱导离子电流的可检测变化，这使得基于纳米孔的感测能够用于各种生物分析应用。在这项研究中，一个瞬态的连续为基础的模型首次开发调查电动粒子易位通过纳米孔通过求解能斯特-普朗克方程的离子浓度，泊松方程的电势和Navier-Stokes方程的流场使用任意拉格朗日-欧拉（ALE）方法。当施加的电场相对较低时，预期电流阻断。此外，当与带电粒子相邻的双电层（EDL）相对较厚时，粒子可以被捕获在纳米孔的入口处。当施加的电场相对高时，颗粒总是可以通过电泳通过纳米孔。然而，如果颗粒的EDL相对较厚，则预测电流增强。所得数值结果与已有的实验结果定性一致。研究还发现，粒子的初始取向可以显着影响粒子的移位和通过纳米孔的离子电流。此外，相对高的电场倾向于使颗粒排列成其最长轴平行于局部电场。然而，颗粒从纳米孔的中心线的初始横向偏移起到次要作用。
Nanoparticle electrophoretic translocation through a single nanopore induces a detectable change in the ionic current, which enables the nanopore-based sensing for various bio-analytical applications. In this study, a transient continuum-based model is developed for the first time to investigate the electrokinetic particle translocation through a nanopore by solving the Nernst-Planck equations for the ionic concentrations, the Poisson equation for the electric potential and the Navier-Stokes equations for the flow field using an arbitrary Lagrangian-Eulerian (ALE) method. When the applied electric field is relatively low, a current blockade is expected. In addition, the particle could be trapped at the entrance of the nanopore when the electrical double layer (EDL) adjacent to the charged particle is relatively thick. When the electric field imposed is relatively high, the particle can always pass through the nanopore by electrophoresis. However, a current enhancement is predicted if the EDL of the particle is relatively thick. The obtained numerical results qualitatively agree with the existing experimental results. It is also found that the initial orientation of the particle could significantly affect the particle translocation and the ionic current through a nanopore. Furthermore, a relatively high electric field tends to align the particle with its longest axis parallel to the local electric field. However, the particle's initial lateral offset from the centerline of the nanopore acts as a minor effect.