Nanopores functionalized with synthetic or biological
polyelectrolyte (PE) brushes have significant potentials to rectify
ionic current and probe single biomacromolecules. In this work,
electric-field-induced ion transport and the resulting conductance in
a PE-modified nanopore are theoretically studied using a
continuum-based model, composed of coupled Poisson−Nernst−
Planck (PNP) equations for the ionic mass transport, and Stokes
and Brinkman equations for the hydrodynamic fields in the exterior
and interior of the PE layer, respectively. Because of the competition
between the transport of counterions and co-ions in the nanopore,
two distinct types of ion concentration polarization (CP) occur at
either opening of the PE-modified nanopore. These distinct CP
behaviors, which significantly affect the nanopore conductance, can
be easily manipulated by adjusting the bulk salt concentration and the imposed potential bias. The induced CP in the PEmodified nanopore is more appreciable than that in the corresponding bare solid-state nanopore.
關聯:
Journal of Physical Chemistry C 116(15), pp.8672-8677
