DNA-graphene interactions during translocation through nanogaps.

Yogendra Kumar Mishra,Hiral N Patel,Henk W.Ch Postma,Charles Etienne,Mark R Paul,Subba Ramaiah Kodigala,Ian Carroll,Sandeep Sankararaman,Rodolfo Lopez

doi:10.1371/journal.pone.0171505

Yogendra Kumar Mishra, Hiral N Patel + Show 7 more

Open Access

https://doi.org/10.1371/journal.pone.0171505

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Journal: PloS one	Publication Date: Feb 3, 2017
Citations: 31	License type: CC BY 4.0

Affiliation: California State University, Northridge, Virginia Tech

Abstract

We study how double-stranded DNA translocates through graphene nanogaps. Nanogaps are fabricated with a novel capillary-force induced graphene nanogap formation technique. DNA translocation signatures for nanogaps are qualitatively different from those obtained with circular nanopores, owing to the distinct shape of the gaps discussed here. Translocation time and conductance values vary by ∼ 100%, which we suggest are caused by local gap width variations. We also observe exponentially relaxing current traces. We suggest that slow relaxation of the graphene membrane following DNA translocation may be responsible. We conclude that DNA-graphene interactions are important, and need to be considered for graphene-nanogap based devices. This work further opens up new avenues for direct read of single molecule activitities, and possibly sequencing.

Highlights

Solid-state and biological nanopores hold great promise as analytical single-molecule tools [1]
Upon introduction of double-stranded DNA (dsDNA) on the cis side of the chamber and application of a bias voltage between the two Ag/AgCl electrodes, brief changes in the ion current are observed (Fig 5A). These events only occur after introduction of the dsDNA, we attribute them to translocation of dsDNA through the graphene nanogap
The conductance during an event is dominated by the counterion current along the DNA molecule, while at high concentrations, the conductance is dominated by doi:10.1371/journal.pone.0171505.g006

Summary

Introduction

Solid-state and biological nanopores hold great promise as analytical single-molecule tools [1]. They enable study of folding dynamics [2], enzyme activity [3], direct detection of DNA knots [4], and detection of single-nucleotide polymorphisms [5]. First results for the MiniIon nanopore sequencer are promising, but show a relatively high error rate [16]. While this may be improved by repeated sequencing of identical molecules, this means there is still an unmet need in single-molecule de novo sequencing. Graphene nanogaps are a promising candidate for such a sequencing device [17,18,19,20]

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Conclusion