DNA Sequencing with ssDNA Rectification in a Nanogap Gated by N-Terminated Carbon Nanotube Electrodes

Fast, reliable and inexpensive DNA sequencing is an important pursuit in healthcare, especially in personalized medicine with possible deep societal impacts. Despite significant progress of various nanopore-based sequencing configurations, challenges that remain in resolution and chromosome-size long readout call for new approaches. Here we found strong rectification in transverse current during ssDNA translocation through a nanopore with side-embedded N-terminated carbon nanotube electrodes. Employing DFT and Non-Equilibrium Green’s Function formalism, we show that the rectifying ratio (response to square pulses of alternating bias) bears high nucleobase specificity. The rectification arises due to bias-dependent resistance asymmetry on the deoxyribonucleotide-electrode interfaces. The asymmetry induces molecular charging and HOMO pinning to the electrochemical potential of one of the electrodes, assisted by an in-gap electric field effect caused by dipoles at the terminated electrode ends. We propose re...