Bilayer Graphene Lateral Contacts for DNA Sequencing

TL;DR

This paper proposes a bilayer graphene nanopore device with lateral contacts for DNA sequencing, leveraging the interlayer distance for precise electronic coupling to distinguish nucleobases efficiently.

Contribution

It introduces a novel device architecture using bilayer graphene nanopores with lateral contacts, enabling accurate sequencing of single- and double-stranded DNA without ultra-sharp probes.

Findings

Device can sequence single-stranded DNA.

Potential to sequence double-stranded DNA.

Avoids fabrication challenges of subnanometer probes.

Abstract

Translocation of DNA through a nanopore with embedded electrodes is at the centre of new rapid inexpensive sequencing methods which allow distinguishing the four nucleobases by their different electronic structure. However, the subnanometer separation between nucleotides in DNA requires ultra-sharp probes. Here, we propose a device architecture consisting of a nanopore formed in bilayer graphene, with the two layers acting as separate electrical contacts. The 0.34 nm interlayer distance of graphene is ideally suited for electrical coupling to a single nucleobase, avoiding the difficulty of fabricating probes with subnanometer precision. The top and bottom graphene electrodes contact the target molecule from the same lateral side, removing the orders-of-magnitude tunneling current variations between smaller pyrimidine bases and larger purine bases. We demonstrate that incorporating techniques for molecular manipulation enables the proposed device to sequence single-stranded DNA and that it offers even the prospect of sequencing double-stranded DNA.