Effect of Surface Charge on the Resistive Pulse Waveshape during Particle Translocation through Glass Nanopores
Effect of Surface Charge on the Resistive Pulse Waveshape during Particle Translocation through Glass Nanopores
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DOI：
10.1021/jp412148s
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发表时间：
2014-02-06
影响因子：
3.7
通讯作者：
White, Henry S.
中科院分区：
文献类型：
--
作者：
Lan, Wen-Jie;Kubeil, Clemens;White, Henry S.
本文描述了静电相互作用对带电纳米颗粒通过圆锥形带电玻璃纳米孔移位所产生的阻性脉冲波形的影响的基础研究。与通常与阻性脉冲法相关的单峰阻性脉冲不同，当在孔内部和外部溶液之间施加高负电位(低于-0.4V)时，在电流时间记录中观察到双相脉冲，其中在正常电流下降之前是电流增加。两相脉冲是由移位粒子的表面电荷引起的离子电导率增加和由于粒子对电解液的体积排斥而导致的电流减小的抵消效应的结果。基于耦合Poisson-Nernst-Planck方程的有限元模拟和粒子轨迹计算成功地捕捉到了随着外加电压的变化，波形从单个阻性脉冲到两相响应的演化过程。模拟结果表明，纳米孔和颗粒的表面电荷是导致形状随电压变化的主要原因。此外，使用高离子强度溶液或高压来驱动颗粒转移被发现消除了两相反应。前者是由于屏蔽了双电层，而后者是由于溶液流动阻止了在纳米孔内形成平衡的双层离子分布，类似于以前报道的当溶液流过纳米孔时消除了离子电流整流。
This paper describes a fundamental study of the effect of electrostatic interactions on the resistive pulse waveshape associated with translocation of charged nanoparticles through a conical-shaped, charged glass nanopore. In contrast to single-peak resistive pulses normally associated with resistive-pulse methods, biphasic pulses, in which the normal current decrease is preceded by a current increase, were observed in the current-time recordings when a high negative potential (lower than -0.4 V) is applied between the pore interior and the external solution. The biphasic pulse is a consequence of the offsetting effects of an increased ion conductivity induced by the surface charge of the translocating particle and the current decrease due to the volume exclusion of electrolyte solution by the particle. Finite-clement simulations based on the coupled Poisson-Nernst-Planck equations and a particle trajectory calculation successfully capture the evolution of the waveshape from a single resistive pulse to a biphasic response as the applied voltage is varied. The simulation results demonstrate that the surface charges of the nanopore and the particle are responsible for the voltage-dependent shape evolution. Additionally, the use of high ionic strength solution or high pressures to drive particle translocation was found to eliminate the biphasic response. The former is due to the screening of the electrical double layer, while the latter results from the solution flow preventing formation of an equilibrium double layer ion distribution within the nanopore, similar to the previously reported elimination of ion current rectification when solution flows through a nanopore.