Effect of Salt Concentration on the Electrophoretic Speed of a Polyelectrolyte through a Nanopore

In a previous paper [S. Ghosal, Phys. Rev. E 74, 041901 (2006)] a hydrodynamic model for determining the electrophoretic speed of a polyelectrolyte through an axially symmetric slowly varying nanopore was presented in the limit of a vanishingly small Debye length. Here the case of a finite Debye layer thickness is considered while restricting the pore geometry to that of a cylinder of length much larger than the diameter. Further, the possibility of a uniform surface charge on the walls of the nanopore is taken into account. It is thereby shown that the calculated transit times are consistent with recent measurements in silicon nanopores.

Figure 1

Geometry of the pore region.

Figure 2

Translocation times for $16.5\mu \mathrm{m}$ long dsDNA through a 10.2 nm diameter solid state nanopore. Solid line is calculated from Eqs. (15, 16, 17); the symbols are replotted from the data presented in Fig. 4(b) (inset) of Smeets et al. [10].