The Statistics of DNA Capture by a Solid-State Nanopore

TL;DR

This study investigates how solid-state nanopores capture and translocate DNA, revealing a bias towards end capture driven by entropy and analyzing the dynamics of folded DNA translocation.

Contribution

It provides a statistical analysis and theoretical explanation of DNA capture bias and translocation dynamics in solid-state nanopores, highlighting entropy effects.

Findings

Bias towards end capture due to configurational entropy

Quantified fluctuations in translocation speed

Length dependence of translocation dynamics

Abstract

A solid-state nanopore can electrophoretically capture a DNA molecule and pull it through in a folded configuration. The resulting ionic current signal indicates where along its length the DNA was captured. A statistical study using an 8 nm wide nanopore reveals a strong bias favoring the capture of molecules near their ends. A theoretical model shows that bias to be a consequence of configurational entropy, rather than a search by the polymer for an energetically favorable configuration. We also quantified the fluctuations and length-dependence of the speed of simultaneously translocating polymer segments from our study of folded DNA configurations.