Concentration-Gradient-Dependent Ion Current Rectification in Charged Conical Nanopores
Concentration-Gradient-Dependent Ion Current Rectification in Charged Conical Nanopores
复制标题
带电锥形纳米孔中浓度梯度相关的离子电流整流
DOI：
10.1021/la203837q
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发表时间：
2012-01-31
期刊：
影响因子：
3.9
通讯作者：
Jiang, Lei
中科院分区：
文献类型：
--
作者：
Cao, Liuxuan;Guo, Wei;Jiang, Lei
在带负电荷的锥形纳米孔中，离子电流整流（ICR）是由电解质浓度梯度控制的，这取决于离子扩散的方向。ICR的程度随着正向浓度差的增大而增强。当浓度梯度反向施加时，观察到不寻常的整流反转。提出了一种基于泊松和能-普朗克（PNP）耦合方程的数值模拟方法，用于求解带有扩散离子流的带电结构不对称纳米流体通道中的离子分布和离子通量。模拟结果定性地描述了实验数据表明的锥形纳米孔中扩散诱导的ICR行为。浓度梯度相关的ICR增强和反转归因于几何诱导的不对称离子输运和扩散离子流之间的合作和竞争。本研究提高了我们对非对称纳米流体通道中ICR与离子浓度差异相关的理解，并提供了对整流生物离子通道的深入了解。
Ion current rectification (ICR) in negatively charged conical nanopores is shown to be controlled by the electrolyte concentration gradient depending on the direction of ion diffusion. The degree of ICR is enhanced with the increasing forward concentration difference. An unusual rectification inversion is observed when the concentration gradient is reversely applied. A numerical simulation based on the coupled Poisson and Nernst-Planck (PNP) equations is proposed to solve the ion distribution and ionic flux in the charged and structurally asymmetric nanofluidic channel with diffusive ion flow. Simulation results qualitatively describe the diffusion-induced ICR behavior in conical nanopores suggested by the experimental data. The concentration-gradient-dependent ICR enhancement and inversion is attributed to the cooperation and competition between geometry-induced asymmetric ion transport and the diffusive ion flow. The present study improves our understanding of the ICR in asymmetric nanofluidic channels associated with the ion concentration difference and provides insight into the rectifying biological ion channels.