Article

Electrokinetic particle translocation through a nanopore containing a floating electrode

Department of Mechanical and Aerospace Engineering, Old Dominion University, Norfolk, VA 23529-0247, USA.
Electrophoresis (Impact Factor: 3.16). 07/2011; 32(14):1864-74. DOI: 10.1002/elps.201100050
Source: PubMed

ABSTRACT Electrokinetic particle translocation through a nanopore containing a floating electrode is investigated by solving a continuum model, composed of the coupled Poisson-Nernst-Planck (PNP) equations for the ionic mass transport and the modified Stokes equations for the flow field. Two effects due to the presence of the floating electrode, the induced-charge electroosmosis (ICEO) and the particle-floating electrode electrostatic interaction, could significantly affect the electrokinetic mobility of DNA nanoparticles. When the electrical double layers (EDLs) of the DNA nanoparticle and the floating electrode are not overlapped, the particle-floating electrode electrostatic interaction becomes negligible. As a result, the DNA nanoparticle could be trapped near the floating electrode arising from the induced-charge electroosmosis when the applied electric field is relatively high. The presence of the floating electrode attracts more ions inside the nanopore resulting in an increase in the ionic current flowing through the nanopore; however, it has a limited effect on the deviation of the current from its base current when the particle is far from the pore.

0 Followers
 · 
146 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: Electrokinetics has emerged as one of the most promising techniques to transport and manipulate ions, fluid and particles in micro/nanofluidic devices. Field effect permits flexible and rapid control of the surface charge property on the channel wall, which in turn offers a more sophisticated control of the electrokinetic transport phenomena in micro/nanofluidics. In the field effect control, a potential named as gate potential is applied to a gate electrode patterned on the outer surface of the dielectric channel wall in contact with an aqueous solution, and the imposed radial electric field can effectively modulate the surface potential at the channel/liquid interface, resulting in the redistribution of ions and accordingly the ionic conductance of a nanochannel. The modulation of the surface potential at the channel/liquid interface can also affect the electrokinetic transport of fluids and particles. This tutorial review elucidates the physical mechanism and discusses some typical results of the field effect control of ion, fluid and particle electrokinetic transport in micro/nanofluidics.
    Sensors and Actuators B Chemical 01/2012; 161(1):1150-1167. DOI:10.1016/j.snb.2011.12.004 · 3.84 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Electrostatic interactions between two charged dielectric objects highly depend on their surface charge. Most existing studies assume constant surface charge densities between the two interacting objects regardless of the separation distance between them. The surface charge of a spherical silica nanoparticle interacting with a flat silica plate is investigated numerically as a function of the separation distance normalized with the electrical double layer thickness (κh), pH, and background salt concentration. The numerical model employs Poisson–Nernst–Planck equations for ionic mass transport and considers surface charge regulation in the presence of multiple ionic species. Relatively weak interactions between the nanoparticle and the plate are observed for κh 1, resulting in uniform surface charge densities. Because of curvature, the surface charge density of the nanoparticle is higher than that of the plate. Strong interactions are observed for κh ≤ 1, leading to spatially nonuniform surface charge densities on the nanoparticle and the plate. This effect increases with decreased separation distance (κh). Enhanced proton concentration in the gap between the particle and the plate leads to reduced surface charge densities on the two objects.
    The Journal of Physical Chemistry C 05/2014; 118(20):10927–10935. DOI:10.1021/jp5023554 · 4.84 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The development of nanopore fabrication methods during the past decade has led to the resurgence of resistive-pulse analysis of nanoparticles. The newly developed resistive-pulse methods enable researchers to simultaneously study properties of a single nanoparticle and statistics of a large ensemble of nanoparticles. This review covers the basic theory and recent advances in applying resistive-pulse analysis and extends to more complex transport motion (e.g., stochastic thermal motion of a single nanoparticle) and unusual electrical responses (e.g., resistive-pulse response sensitive to surface charge), followed by a brief summary of numerical simulations performed in this field. We emphasize the forces within a nanopore governing translocation of low-aspect ratio, nondeformable particles but conclude by also considering soft materials such as liposomes and microgels. Expected final online publication date for the Annual Review of Analytical Chemistry Volume 7 is June 15, 2014. Please see http://www.annualreviews.org/catalog/pubdates.aspx for revised estimates.
    Annual Review of Analytical Chemistry (2008) 08/2013; DOI:10.1146/annurev-anchem-071213-020107 · 7.81 Impact Factor