DNA Base Detection Using a Single-Layer MoS₂

TLDR

Nanopore sequencing offers high‑resolution DNA base detection, yet solid‑state and biological nanopores suffer from low SNR (<10) and thickness (>5 nm), whereas 2‑D materials such as graphene provide sub‑nanometer thickness and an SNR of ~3. MoS₂ nanopores feature a craftable pore architecture composed of Mo and S atoms at the edge, allowing optimization of sequencing signals. Atomistic and quantum simulations reveal that single‑layer MoS₂ nanopores achieve an SNR >15, generate four distinct low‑noise ionic current signatures for each nucleobase, and display characteristic density‑of‑states and band‑gap changes that make it a promising material for transverse‑current tunneling base detection.

Abstract

Nanopore-based DNA sequencing has led to fast and high-resolution recognition and detection of DNA bases. Solid-state and biological nanopores have low signal-to-noise ratio (SNR) (< 10) and are generally too thick (> 5 nm) to be able to read at single-base resolution. A nanopore in graphene, a 2-D material with sub-nanometer thickness, has a SNR of ∼3 under DNA ionic current. In this report, using atomistic and quantum simulations, we find that a single-layer MoS2 is an extraordinary material (with a SNR > 15) for DNA sequencing by two competing technologies (i.e., nanopore and nanochannel). A MoS2 nanopore shows four distinct ionic current signals for single-nucleobase detection with low noise. In addition, a single-layer MoS2 shows a characteristic change/response in the total density of states for each base. The band gap of MoS2 is significantly changed compared to other nanomaterials (e.g., graphene, h-BN, and silicon nanowire) when bases are placed on top of the pristine MoS2 and armchair MoS2 nanoribbon, thus making MoS2 a promising material for base detection via transverse current tunneling measurement. MoS2 nanopore benefits from a craftable pore architecture (combination of Mo and S atoms at the edge) which can be engineered to obtain the optimum sequencing signals.