Fabrication and characterization of a solid-state nanopore with self-aligned carbon nanoelectrodes for molecular detection

Abstract

Stochastic molecular sensors based on resistive pulse nanopore modalities are envisioned as facile DNA sequencers. However, recent advances in nanotechnology fabrication have highlighted promising alternative detection mechanisms with higher sensitivity and potential single-base resolution. In this paper we present the novel self-aligned fabrication of a solid-state nanopore device with integrated transverse graphene-like carbon nanoelectrodes for polyelectrolyte molecular detection. The electrochemical transduction mechanism is characterized and found to result primarily from thermionic emission between the two transverse electrodes. Response of the nanopore to Lambda dsDNA and short (16-mer) ssDNA is demonstrated and distinguished.

Single‐Molecule Electrical Detection with Real‐Time Label‐Free Capability and Ultrasensitivity

“…Reliable molecular recognition with a tunneling junction requires a molecular‐scale gap between the electrodes. Fabrication techniques for making these nanogap electrodes have been based on scanning tunneling microscopy (STM), electromigration, mechanically controllable break junctions (MCBJs), carbon nanowires, or multilayer structures . With a precisely controlled gap to fit the target molecule, single‐molecule detection can be realized with a tunneling junction.…”

“…Furthermore, the chains may move back and forth through the nanogap, which duplicates detection. Nanopores can constrain single molecular chains to pass through unidirectionally, as practiced in FET nanowire–nanopore structures . Thus, introducing a nanopore to the tunneling junction may be necessary to control molecular chain diffusion through the nanogap.…”

Recent trends in nanopores for biotechnology

“…The electronic properties of graphene, its robustness, atomic thickness, and ion impermeability, make it an intriguing material for nanopore-based electronic sequencing of DNA molecules. New improvements in the formation of suspended graphene flake membranes [17] and nanopore fabrication in self-aligned carbon electrodes [18] have recently been reported, which facilitate the integration of carbon nanostructure into nanopore technology.…”

Fixed-Gap Tunnel Junction for Reading DNA Nucleotides

“… 3 To overcome this limitation, Zwolak and DiVentra proposed sensing DNA nucleotides via measurements of transverse tunnel current as a DNA molecule is passed through a gap between two electrodes. 4 Attempts to make solid-state, fixed gap tunnel junctions for reading DNA ncleotides are described by Fischbein et al , 5 Healy et al , 6 Spinney et al , 7 Ivanov et al ( 8 , 9 ) Redenovic et al ( 10 ) and Liang and Chou. 11 In the best cases, these papers report the detection of whole DNA molecules as single events with no chemical information.…”

“…Electrode gaps for sequencing DNA have been made by cutting gold 5 , 6 or carbon 7 nanowires with an electron beam, by using electromigration 16 or mechanical stress 18 to break a gold wire, or electron-beam induced deposition of opposed pairs of wires. 9 , 19 An alternative approach is to use a layered structure to define the size of a gap, allowing molecules to bond between electrodes exposed at the edges of the device.…”