I.D. Kosinska, I. Goychuk, M. Kostur, G. Schmid, and P. Hänggi
Transport in nanopores.
Ion transport in biological and synthetic nanochannels is characterized
by such phenomena as ion current fluctuations, and rectification.
Recently, it has been shown that the nanofabricated
synthetic pores can mimic some transport properties of biological ion channels
[P. Yu. Apel et al., Nucl. Instrum. Methods Phys. Res. B 184, 337 2001;
Z. Siwy et al., Europhys. Lett. 60, 349 2002].
The ion current rectification is studied within a reduced 1D PNP model
for synthetic pores.
A conical channel of nm to a few hundred of nm in diameter,
and of µm long is considered in the limit where the channel length exceed much the Debye screening length.
The channel wall is assumed to be weakly charged.
Ion transport is described
by the nonequillibrium steady-state solution of
the Poisson-Nernst-Planck system within a singular perturbation treatment.
The role of boundary conditions is discussed.
A comparison between the numerical and the result of the singular
perturbation theory is presented.