Ionic conduction in non-uniform nanopores and DNA translocation: a Nernst-Planck-Jacobs one-dimensional description

The conduction of an electrolyte solution in the presence of a DNA intruder in a synthetic charged pore is studied by theoretical means. The pore conductivity is controlled by two competing mechanisms: the steric effect of the DNA decreases the current and the extra-surface charges determine an increase in the number of charge carriers that increase the current. By using a Nernst-Planck description of the electrolyte and a one-dimensional advection-diffusion equation similar to the Jacobs-Zwanzig method, we obtain the characteristic curve within the local electroneutrality approximation. Such an information allows predicting the variation of the conductance caused by the DNA intruder and determining the current blockage/enhancement phase diagram.