  In the approach of biomolecules to a nanopore, it is essential to capture the
effects of hydrodynamic anisotropy of the molecules and the near-wall
hydrodynamic interactions which hinder their diffusion. We present a detailed
theoretical analysis of the behaviour of a rod-like molecule attracted
electrostatically by a charged nanopore. We first estimate the time scales
corresponding to Brownian and electrostatic translations and reorientation. We
find that Brownian motion becomes negligible at distances within the pore
capture radius, and numerically determine the trajectories of the nano-rod in
this region to explore the effects of anisotropic mobility. This allows us to
determine the range of directions from the pore in which hydrodynamic
interactions with the boundary shape the approach dynamics and need to be
accounted for in detailed modelling.
