Charge-Wettability interaction in a Graphene-based nanopore modulating DNA translocation.

Translocation of DNA through nanopores under an externally applied electric field for characterization of constituent nucleotides is under intensive research. The major challenge is to control the speed of DNA so that the sensor can catch the variation in the ionic current and can read the individual bases. Researchers have used protein-based biological nanopores which are replaced by solid-state nanopores (SS-NP) because of its benefit of controlled size, surface charge, and surface finishing over biological nanopores. Hence, SS-NP is being potentially used as a rapid DNA sequencing device. However, the thickness of the nanopores fabricated in insulating membranes is equivalent to 15-20 bases thereby, making it difficult to detect each nucleotide. With the advent of 2-D materials, graphene-based membranes with a single atomic thickness (0.34 nm) can be potentially used as a sensor to obtain single-base resolution in the ionic current variation. Towards this here we present full-scale mathematical modelling of DNA translocation through a graphene-based membrane. We consider the coupling of the interfacial interaction of graphene substrate with charge and momentum transport to predict the modified electro-hydrodynamics of the DNA nanoparticle. We include a separate dielectric permittivity of the graphene membrane with a varying surface charge to consider its effect on DNA dynamics in the present model. The present study explores regimes of successful or failed translocation of DNA through graphene-based nanopores with comparatively lower computational costs, unlike typical molecular dynamics simulations.