Nanopores in atomically thin 2D nanosheets limit aqueous ssDNA transport

TL;DR

This study uses computational methods to reveal the physical mechanisms limiting ssDNA transport through nanopores in 2D materials, highlighting the importance of edge passivation and mechanical properties.

Contribution

It demonstrates how the atomic structure and mechanical properties of 2D nanopores influence ssDNA transport, providing insights for designing better sequencing devices.

Findings

Single-layer hBN nanopores hinder ssDNA transport due to inhomogeneous rigidity.

Bilayer hBN nanopores enable continuous ssDNA transport because of smooth, passivated edges.

Transport is affected by solvation effects and DNA desorption energy barriers.

Abstract

Nanopores in 2D materials are highly desirable for DNA sequencing, yet achieving single-stranded DNA (ssDNA) transport through them is challenging. Using density functional theory calculations and molecular dynamics simulations we show that ssDNA transport through a pore in monolayer hexagonal boron nitride (hBN) is marked by a basic nanomechanical conflict. It arises from the notably inhomogeneous flexural rigidity of ssDNA and causes high friction $\textit{via}$ transient DNA desorption costs exacerbated by solvation effects. For a similarly sized pore in bilayer hBN, its self-passivated atomically smooth edge enables continuous ssDNA transport. Our findings shed light on the fundamental physics of biopolymer transport through pores in 2D materials.