Effect of electrodiffusion current flow on electrostatic screening in aqueous pores

A numerical study within the framework of the Poisson-Nernst-Planck equations is conducted to investigate electrostatic screening of charged biomolecules within synthetic pores having diameters of at least 10 Debye lengths. We show that with external biases, the biomolecule charge is only partially screened due to the presence of electro-diffusion 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 biomolecule charge sensing is also discussed. (C) 2008 American Institute of Physics.