Transverse Detection of DNA Using a MoS₂ Nanopore

Abstract

Classical nanopore sensing relies on the measurement of the ion current passing through a nanopore. Whenever a molecule electrophoretically translocates through the narrow constriction, it modulates the ion current. Although this approach allows one to measure single molecules, the access resistance limits the spatial resolution. This physical limitation could potentially be overcome by an alternative sensing scheme taking advantage of the current across the membrane material itself. Such an electronic readout would also allow better temporal resolution than the ionic current. In this work, we present the fabrication of an electrically contacted molybdenum disulfide (MoS2) nanoribbon integrated with a nanopore. DNA molecules are sensed by correlated signals from the ionic current through the nanopore and the transverse current through the nanoribbon. The resulting signal suggests a field-effect sensing scheme where the charge of the molecule is directly sensed by the nanoribbon. We discuss different sensing schemes such as local potential sensing and direct charge sensing. Furthermore, we show that the fabrication of freestanding MoS2 ribbons with metal contacts is reliable and discuss the challenges that arise in the fabrication and usage of these devices.

Wafer‐Scale Fabrication of Nanopore Devices for Single‐Molecule DNA Biosensing using MoS2

“…In principle, these devices can be used for other exciting applications involving wafer-scale flexible electronics [41,[73][74][75] as well as highly efficient osmotic energy harvesting cells [24] or recently emerged extension of nanopore sequencing-a nanopore field-effect transistors enabling both ionic and transverse current based biomolecule detection. [15,76,77] We believe that further integration and parallelization of nanopore based membrane devices will lead to high-throughput usage [78][79][80][81] and in turn will encourage new, emerging, commercial applications of this technology.…”

Interaction dynamics and site-specific electronic recognition of DNA-nicks with 2D solid-state nanopores

“…In DNA translocation experiments, a transmembrane voltage of 100-200 mV is usually set up to thread the biomolecule through the nanopore, which results in observed translocation times are of the order of milliseconds with dwell times of the order of a few 100 μs 49,58 . Higher biases are excluded to avoid membrane damages to the FET device caused by dielectric breakdown.…”

Nanoscale Selective Passivation of Electrodes Contacting a 2D Semiconductor

“…The ribbon located in the middle of the device is placed on top of an 80 nm large aperture, making it effectively freestanding. A nanopore can then be drilled into this freestanding part to deliver molecules to the sensor …”

“…This is especially important for devices that require the 2D material to remain free of contamination at the atomic level. One example of such a device is a field‐effect transistor (FET) coupled with a nanometer‐sized hole (nanopore‐FET) for label‐free single‐molecule detection . In these devices, the 2D material is suspended over an aperture and should stay free of additional layers and contamination to allow the creation of a nanopore and to provide the best possible spatial resolution for sensing …”