Institute of Micro/Nanotechnology, Old Dominion University, Norfolk, VA 23529, USA.
Nanoscale. 2012 Aug 21;4(16):5169-77. doi: 10.1039/c2nr31069d. Epub 2012 Jul 17.
Chemically functionalized nanopores in solid-state membranes have recently emerged as versatile tools for regulating ion transport and sensing single biomolecules. This study theoretically investigated the importance of the bulk salt concentration, the geometries of the nanopore, and both the thickness and the grafting density of the polyelectrolyte (PE) brushes on the electrokinetic ion and fluid transport in two types of PE brush functionalized nanopore: PE brushes are end-grafted to the entire membrane surface (system I), and to its inner surface only (nanopore wall) (system II). Due to a more significant ion concentration polarization (CP), the enhanced local electric field inside the nanopore, the conductance, and the electroosmotic flow (EOF) velocity in system II are remarkably smaller than those in system I. In addition to a significantly enhanced EOF inside the nanopore, the direction of the flow field near both nanopore openings in system I is opposite to that of EOF inside the nanopore. This feature can be applied to regulate the electrokinetic translocation of biomolecules through a nanopore in the nanopore-based DNA sequencing platform.
近年来，固态膜中的化学功能化纳米孔已成为调节离子传输和感测单个生物分子的多功能工具。本研究从理论上研究了本体盐浓度、纳米孔的几何形状以及聚电解质（PE）刷的厚度和接枝密度对两种 PE 刷功能化纳米孔中电动离子和流体输运的重要性：PE 刷末端接枝到整个膜表面（系统 I）和仅接枝到其内表面（纳米孔壁）（系统 II）。由于离子浓度极化（CP）更显著、纳米孔内局部电场增强、电导率和电渗流（EOF）速度在系统 II 中明显小于系统 I。除了在纳米孔内显著增强的 EOF 外，在系统 I 中两个纳米孔开口附近的流场方向与纳米孔内的 EOF 方向相反。此特性可应用于调节基于纳米孔的 DNA 测序平台中纳米孔内生物分子的电动输运。
