Geometric dependence of the conductance drop in a nanopore due to a particle
Published in Phys. Rev. E, 2014
Recommended citation: Sung Kim, Sridhar Kannam, Stefan Harrer, Matthew Downton, Stephen Moore, John Wagner, "Geometric dependence of the conductance drop in a nanopore due to a particle." Phys. Rev. E, 2014. https://link.aps.org/doi/10.1103/PhysRevE.89.042702
1) The effect of a neutral particle on ionic flow through nanopores can be studied using uniform field theory and PNP-NS equations.
2) Pore shape influences current changes due to particles, with both hourglass and cylindrical profiles showing differences.
3) Simple theories may not accurately capture access resistance changes when particles are at the pore entrance, and electro-osmotic flow can be disrupted by large particles.
Abstract
We study the effect of a neutral particle on the ionic flow through a nanopore using a basic uniform field theory and the coupled Poisson-Nernst-Planck and Navier-Stokes (PNP-NS) equations. We consider hourglass and cylindrical pore profiles and examine how the difference in pore shape changes the position dependence of the current change due to the particle. Good quantitative agreement between both calculations is seen, though we find that the simple theory is unable to correctly capture the change in the access resistance of the pore if a particle is placed at the pore entrance. Finally, we examine the spatial variations in the solutions of the PNP-NS equations, finding that the electro-osmotic flow through the pore is completely disrupted for sufficiently large particles.