Rectification properties of conically shaped nanopores: consequences of miniaturization.
Rectification properties of conically shaped nanopores: consequences of miniaturization.
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DOI：
10.1039/c3cp53105h
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发表时间：
2012-09
期刊：
影响因子：
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通讯作者：
Jan-Frederik Pietschmann;Marie-Therese Wolfram;Martin Burger;Christina Trautmann;Gael Nguyen;M. Pevarnik;Veronika Bayer;Z. Siwy
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文献类型：
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作者：
Jan-Frederik Pietschmann;Marie-Therese Wolfram;Martin Burger;Christina Trautmann;Gael Nguyen;M. Pevarnik;Veronika Bayer;Z. Siwy
纳米孔作为生物传感器的模板以及理解纳米级传输现象的模型系统吸引了大量的科学兴趣。迄今为止，纳米孔的实验和理论分析一直集中在理解孔开口直径对离子传输的影响。在这篇文章中，我们提出了系统的研究离子传输性能的依赖性的孔长度。特别注意的是，在具有均匀表面电荷的锥形纳米孔中表现出的离子电流整流的效果。我们发现，减少圆锥形纳米孔的长度显着降低其整流离子电流的能力。然而，短孔的整流性能可以通过调整表面电荷和窄开口的形状来增强。此外，我们还分析了不同孔长的整流行为与离子选择性的关系。所有模拟均使用MsSimPore进行，MsSimPore是用于求解Poisson-Nernst-Planck（PNP）方程的软件包。它基于一种新型的有限元求解器，并允许模拟高达-2 e/nm的表面电荷密度（2）。MsSimPore基于PNP模型的1D简化，但允许使用大量电解质储集器直接处理孔隙，这一功能以前仅用于更高维度的模型。MsSimPore在计算中包括了这些储层，这一特性对于短孔尤其重要，因为在短孔中，离子浓度和电势在孔内以及孔入口附近的区域变化很大。
Nanopores attracted a great deal of scientific interest as templates for biological sensors as well as model systems to understand transport phenomena at the nanoscale. The experimental and theoretical analysis of nanopores has been so far focused on understanding the effect of the pore opening diameter on ionic transport. In this article we present systematic studies on the dependence of ion transport properties on the pore length. Particular attention was given to the effect of ion current rectification exhibited in conically shaped nanopores with homogeneous surface charges. We found that reducing the length of conically shaped nanopores significantly lowered their ability to rectify ion current. However, rectification properties of short pores can be enhanced by tailoring the surface charge and the shape of the narrow opening. Furthermore we analyzed the relationship of the rectification behavior and ion selectivity for different pore lengths. All simulations were performed using MsSimPore, a software package for solving the Poisson-Nernst-Planck (PNP) equations. It is based on a novel finite element solver and allows for simulations up to surface charge densities of -2 e per nm(2). MsSimPore is based on 1D reduction of the PNP model, but allows for a direct treatment of the pore with bulk electrolyte reservoirs, a feature which was previously used in higher dimensional models only. MsSimPore includes these reservoirs in the calculations, a property especially important for short pores, where the ionic concentrations and the electric potential vary strongly inside the pore as well as in the regions next to the pore entrance.