Diffusiophoresis of a pH-regulated polyelectrolyte in a nanopore of nonuniform cross section

Abstract

The diffusiophoresis of a pH-regulated polyelectrolyte (PE) along the axis of a charged nanopore having nonuniform cross section is modeled, aimed with improving the performance of a nanopore-based sensing device for single biomolecules such as DNAs and proteins. Previous analysis based on a rigid particle of constant charge density in a solution containing binary ionic species is extended to a porous, pH-regulated PE in a solution containing multiple ionic species so that the conditions considered are much closer to reality. The behavior of the PE under various conditions is simulated by varying its charge, relative size, position in the nanopore, the solution pH, and the background salt concentration. We show that the PE translocation velocity can be regulated by the pore width and its charged conditions. In particular, both the magnitude and the direction of the translocation velocity can be adjusted. ? 2015, Springer-Verlag Berlin Heidelberg.