Detection of Nucleotides in Hydrated ssDNA via 2-D h-BN Nanopore with Ionic-Liquid/Salt-Water Interface

Accomplishing slow translocation speed with high sensitivity has been the greatest mission for solid-state nanopore (SSN) to electrically detect nucleobases in single-stranded DNA (ssDNA). In this study, a method to detect nucleobases in ssDNA using a SSN is introduced by considerably slowing down the translocation speed and effectively increasing its sensitivity. The ultra-thin titanium dioxide (TiO2) coated hexagonal boron nitride (h-BN) nanopore was fabricated, along with an ionic-liquid [bmim][PF6]/2.0 M KCl aqueous (cis/trans) interfacial system, to increase both the spatial and the temporal resolutions. As the ssDNA molecules entered the nanopore, a brief surge of electrical conductivity was observed, which was followed by multiple resistive pulses from nucleobases during the translocation of ssDNA. The continuous detection of nucleobases using a SSN is a novel achievement, enabled by water molecules bound to ssDNA which increases molecular conductivity of ssDNA and amplifies electrical signals during the translocation event. Along with the experiment, computational simulations using COMSOL are presented to explain the pivotal role of water molecules bound to ssDNA for the detection of nucleobases using a SSN