Modulation of current through a nanopore induced by a charged globule: implications for DNA-docking

TL;DR

This study uses simulations to explore how a charged DNA globule affects nanopore current signatures during docking and translocation, revealing voltage-dependent conductance changes with implications for DNA sequencing.

Contribution

The paper provides a new interpretation of nanopore conductance behavior during DNA docking, highlighting the voltage-dependent effects of a charged globule on current signatures.

Findings

At low voltage, the globule increases pore conductance due to charge enrichment.

At high voltage, the globule reduces conductance by draining charge carriers.

Docking affects translocation signals, impacting sequencing accuracy.

Abstract

The passage of DNA through a nanopore can be effectively decomposed into two distinct phases, docking and actual translocation. In experiments each phase is characterized by a distinct current signature which allows the discrimination of the two events. However, at low voltages a clear distinction of the two phases is lost. By using numerical simulations we clarify how the current signature associated to the docking events depends on the applied voltage. The simulations show that at small voltage the DNA globule enhances the pore conductance due to an enrichment of charge carriers. At high voltage, the globule drains substantial charge carriers from the pore region, thereby reducing the overall conductance. The results provide a new interpretation to the experimental data on conductance and show how docking interferes with the translocation signal, of potential interest for sequencing applications.