The effect of translocating cylindrical particles on the ionic current through a nanopore
The effect of translocating cylindrical particles on the ionic current through a nanopore
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DOI：
10.1529/biophysj.106.089268
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发表时间：
2007-02-15
影响因子：
3.4
通讯作者：
Bau, Haim H.
中科院分区：
文献类型：
--
作者：
Liu, Hui;Qian, Shizhi;Bau, Haim H.
从理论上研究了电场诱导圆柱形粒子通过圆形纳米孔的易位问题。同时求解了溶液中离子浓度场的耦合能思-普朗克方程（多离子模型，MIM）和流场的Stokes方程。将多离子模型的预测结果与基于泊松-玻尔兹曼方程（PBM）和斯摩鲁乔夫斯基滑移速度（SVM）的两种简化模型的预测结果进行了比较。浓度场、通过孔的离子电流和粒子的速度作为粒子大小、位置和电荷的函数来计算；孔隙大小和电荷；电场强度；和体积溶液的浓度。与实验数据的定性一致，MIM预测，根据体溶液的浓度，易位粒子可能阻断或增强离子电流。当双电层厚度较大时，PBM和SVM预测结果与MIM预测结果不一致。描述了PBM和SVM的局限性。将理论预测与用于解释有关DNA分子通过纳米孔易位的实验数据进行比较。
The electric field-induced translocation of cylindrical particles through nanopores with circular cross sections is studied theoretically. The coupled Nernst-Planck equations (multi-ion model, MIM) for the concentration fields of the ions in solution and the Stokes equation for the flow field are solved simultaneously. The predictions of the multi-ion model are compared with the predictions of two simplified models based on the Poisson-Boltzmann equation (PBM) and the Smoluchowski's slip velocity (SVM). The concentration field, the ionic current though the pore, and the particle's velocity are computed as functions of the particle's size, location, and electric charge; the pore's size and electric charge; the electric field intensity; and the bulk solution's concentration. In qualitative agreement with experimental data, the MIM predicts that, depending on the bulk solution's concentration, the translocating particle may either block or enhance the ionic current. When the thickness of the electric double layer is relatively large, the PBM and SVM predictions do not agree with the MIM predictions. The limitations of the PBM and SVM are delineated. The theoretical predictions are compared with and used to explain experimental data pertaining to the translocation of DNA molecules through nanopores.