Nanoparticle Transport in Conical-Shaped Nanopores
Nanoparticle Transport in Conical-Shaped Nanopores
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DOI：
10.1021/ac200312n
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发表时间：
2011-05-15
影响因子：
7.4
通讯作者：
White, Henry S.
中科院分区：
文献类型：
--
作者：
Lan, Wen-Jie;Holden, Deric A.;White, Henry S.
本报告介绍了纳米颗粒在玻璃膜内的锥形孔中传输现象的基础研究。利用库尔特反原理（或“电阻脉冲”方法）研究了带电聚苯乙烯（PS）纳米颗粒（半径为80和160纳米）的电泳易位，在该原理中，当纳米颗粒被驱动穿过膜时，记录了随时间变化的纳米孔电流。粒子通过锥形纳米孔的移位产生一个方向依赖的不对称三角形电阻脉冲。由于锥形纳米孔的感应区位于孔板上，因此纳米颗粒通过该区域的易位非常快，导致本研究中使用的纳米孔的脉冲宽度接近200 μ s。在80和160纳米半径的粒子中，易位率与纳米粒子浓度呈线性关系，从10(7)到10（11）个/mL，并且电阻脉冲的大小与粒子体积大致成正比。基于连续介质理论的离子通量有限元模拟与基于动态电动力的纳米粒子轨迹计算相结合，计算了纳米粒子通过锥形纳米孔时随位置和时间变化的速度。计算结果用于计算锥形孔隙的电阻脉冲电流-时间响应，从而比较实验和模拟脉冲高度和移位次数。仿真和实验结果表明，纳米颗粒的大小可以根据脉冲高度来区分，而根据移位时间来区分的程度较小。
This report presents a fundamental study of nanoparticle transport phenomena in conical-shaped pores contained within glass membranes. The electrophoretic translocation of charged polystyrene (PS) nanoparticles (80- and 160-nm-radius) was investigated using the Coulter counter principle (or "resistive-pulse" method) in which the time-dependent nanopore current is recorded as the nanoparticle is driven across the membrane. Particle translocation through the conical-shaped nanopore results in a direction-dependent and asymmetric triangular-shaped resistive pulse. Because the sensing zone of conical-shaped nanopores is localized at the orifice, the translocation of nanoparticles through this zone is very rapid, resulting in pulse widths of similar to 200 mu s for the nanopores used in this study. A linear dependence between translocation rate and nanoparticle concentration was observed from 10(7) to 10(11) partides/mL for both 80- and 160-nn-radius particles, and the magnitude of the resistive pulse scaled approximately in proportion to the particle volume. A finite-element simulation based on continuum theory to compute ion fluxes was combined with a dynamic electric force-based nanoparticle trajectory calculation to compute the position- and time-dependent nanoparticle velocity as the nanoparticle translocates through the conical-shaped nanopore. The computational results were used to compute the resistive pulse current-time response for conical-shaped pores, allowing comparison between experimental and simulated pulse heights and translocation times. The simulation and experimental results indicate that nanoparticle size can be differentiated based on pulse height, and to a lesser extent based on translocation time.