Effect of Electro-Diffusion Current Flow on Electrostatic Screening in Aqueous Pores

Abstract

A numerical study within the framework of the Poisson-Nernst-Planck equations is conducted to investigate electrostatic screening of charged bio-molecules within synthetic pores having diameters of at least 10 Debye lengths. We show that with external biases, the bio-molecule charge is only partially screened due to the presence of electrodiffusion current flow. This is considerably different from the equilibrium Debye-Huckel screening behavior and will result in long-range electrostatic interactions. The potential application to direct bio-molecule charge sensing is also discussed.