  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.
