2 research outputs found
DNA Electrokinetic Translocation through a Nanopore: Local Permittivity Environment Effect
The effect of the local liquid permittivity surrounding
the DNA
nanoparticle, referred to as the local permittivity environment (LPE)
effect, on its electrokinetic translocation through a nanopore is
investigated for the first time using a continuum-based model, composed
of the coupled Poisson–Nernst–Planck (PNP) equations
for the ionic mass transport and the Stokes and
Brinkman equations for the hydrodynamic fields in the region outside
of the DNA and within the ion-penetrable layer of the DNA nanoparticle,
respectively. The nanoparticle translocation velocity and the resulting
current deviation are systematically investigated for both uniform
and spatially varying permittivities surrounding the DNA nanoparticle
under various conditions. The LPE effect in general reduces the particle
translocation velocity. The LPE effect on the current deviation is
insignificant when the imposed electric field is relatively high.
However, when the electric field and the bulk electrolyte concentration
are relatively low, both current blockade and enhancement are predicted
with the LPE effect incorporated, while only current blockade is predicted
with the assumption of constant liquid permittivity. It is thereby
shown that regardless of the electric field imposed the predictions
on ionic current with considering the LPE effect are in good qualitative
agreement with the experimental observations obtained in the literature
Controlling pH-Regulated Bionanoparticles Translocation through Nanopores with Polyelectrolyte Brushes
A novel polyelectrolyte (PE)-modified nanopore, comprising
a solid-state nanopore functionalized by a nonregulated PE brush layer
connecting two large reservoirs, is proposed to regulate the electrokinetic
translocation of a soft nanoparticle (NP), comprising a rigid core
covered by a pH-regulated, zwitterionic, soft layer, through it. The
type of NP considered mimics bionanoparticles such as proteins and
biomolecules. We find that a significant enrichment of H<sup>+</sup> occurs near the inlet of a charged solid-state nanopore, appreciably
reducing the charge density of the NP as it approaches there, thereby
lowering the NP translocation velocity and making it harder to thread
the nanopore. This difficulty can be resolved by the proposed PE-modified
nanopore, which raises effectively both the capture rate and the capture
velocity of the soft NP and simultaneously reduces its translocation
velocity through the nanopore so that both the sensing efficiency
and the resolution are enhanced. The results gathered provide a conceptual
framework for the interpretation of relevant experimental data and
for the design of nanopore-based devices used in single biomolecules
sensing and DNA sequencing