Steric modulation of ionic currents in DNA translocation through nanopores

TL;DR

This paper presents a theoretical study on how the ionic conductance during DNA translocation through nanopores is affected by electrolyte molarity, pore geometry, and surface charge, providing a model that matches experimental data.

Contribution

It introduces a Poisson-Nernst-Planck based model to predict conductance modulation due to DNA and nanopore properties, offering a comprehensive conductance diagram.

Findings

The model accurately reproduces experimental conductance data.

Conductance varies with electrolyte molarity and pore dimensions.

A conductance diagram distinguishes reduced and enhanced conductivity regions.

Abstract

Ionic currents accompanying DNA translocation strongly depend on molarity of the electrolyte solution and the shape and surface charge of the nanopore. By means of the Poisson-Nernst-Planck equations it is shown how conductance is modulated by the presence of the DNA intruder and as a result of competing electrostatic and confinement factors. The theoretical results reproduce quantitatively the experimental ones and are summarized in a conductance diagram that allows distinguishing the region of reduced conductivity from the region of enhanced conductivity as a function of molarity and the pore dimension.