School of Mechanical and Materials Engineering, Washington State University, Pullman, Washington 99164, USA.
Electrophoresis. 2012 Jan;33(2):325-33. doi: 10.1002/elps.201100201.
Recent experimental studies show that electrokinetic phenomena such as electroosmosis and electrophoresis can be used to separate nanoparticles on the basis of their size and charge using nanopore-based devices. However, the efficient separation through a nanopore depends on a number of factors such as externally applied voltage, size and charge density of particle, size and charge density of membrane pore, and the concentration of bulk electrolyte. To design an efficient nanopore-based separation platform, a continuum-based mathematical model is used for fluid. The model is based on Poisson-Nernst-Planck equations along with Navier-Stokes equations for fluid flow and on the Langevin equation for particle translocation. Our numerical study reveals that membrane pore surface charge density is a vital parameter in the separation through a nanopore. In this study, we have simulated high-density lipoprotein (HDL) and low-density lipoprotein (LDL) as the sample nanoparticles to demonstrate the capability of such a platform. Numerical results suggest that efficient separation of HDL from LDL in a 0.2 M KCL solution (resembling blood buffer) through a 150 nm pore is possible if the pore surface charge density is ∼ -4.0 mC/m(2). Moreover, we observe that pore length and diameter are relatively less important in the nanoparticle separation process considered here.
最近的实验研究表明，基于电动力学现象（如电渗流和电泳）可以使用基于纳米孔的设备根据颗粒的大小和电荷对纳米颗粒进行分离。然而，通过纳米孔的有效分离取决于许多因素，如外加电压、颗粒的大小和电荷密度、膜孔的大小和电荷密度以及体相电解质的浓度。为了设计高效的基于纳米孔的分离平台，我们使用基于连续体的数学模型来模拟流体。该模型基于泊松-纳维-斯托克斯方程（Poisson-Nernst-Planck equations）来描述流体流动，基于朗之万方程（Langevin equation）来描述颗粒的输运。我们的数值研究表明，膜孔表面电荷密度是通过纳米孔进行分离的一个重要参数。在这项研究中，我们模拟了高密度脂蛋白（HDL）和低密度脂蛋白（LDL）作为样品纳米颗粒，以证明这种平台的能力。数值结果表明，如果孔表面电荷密度约为 -4.0 mC/m²，则可以在 0.2 M KCL 溶液（类似于血液缓冲液）中通过 150nm 的孔有效地将 HDL 从 LDL 中分离出来。此外，我们观察到在考虑的纳米颗粒分离过程中，孔的长度和直径相对不太重要。
