Diffusiophoresis of a pH-Regulated Polyelectrolyte in a Nanopore of Nonunifrom Cross Section
Chun-Yuan Su,1 Jyh-Ping Hsu,1,* Shiojenn Tseng2,*
1Department of Chemical Engineering, National Taiwan University, Taipei, Taiwan 10617 2Department of Mathematics, Tamkang University, Tamsui, Taipei, Taiwan 25137
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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, and 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.