Lattice-Boltzmann simulations of ionic current modulation by DNA translocation

We present a numerical study of the effect of DNA translocation on the ionic current through a nanopore. We use a coarse-grained model to solve the electrokinetic equations at the Poisson-Boltzmann level for the microions, coupled to a lattice-Boltzmann equation for the solvent hydrodynamics. In most cases, translocation leads to a reduction in the ionic current. However, at low salt concentrations ( large screening lengths) we find ionic current enhancement due to translocation. In an unstructured pore, translocation of the helical charge distribution of the DNA has no effect on the ionic current. However, if a localized charge probe is placed on the wall of the nanopore, we observe ionic current modulations that, though weak, should be experimentally observable.