Ab initio study of electron transport in dry poly(G)-poly(C) A-DNA strands

TL;DR

This study uses first-principles methods to analyze how electron transport in dry poly(G)-poly(C) DNA strands is affected by localization and disorder, revealing sequence-specific tunneling and inelastic effects.

Contribution

It provides a detailed ab initio analysis of electron transport in DNA, highlighting the roles of localization, electrostatic disorder, and short-range tunneling mechanisms.

Findings

Localization suppresses conductance in DNA strands.

Electrostatic disorder from water layers impacts electron transport.

Transport involves sequence-specific tunneling and diffusive processes.

Abstract

The bias-dependent transport properties of short poly(G)-poly(C) A-DNA strands attached to Au electrodes are investigated with first principles electronic transport methods. By using the non- equilibrium Green's function approach combined with self-interaction corrected density functional theory, we calculate the fully self-consistent coherent I-V curve of various double-strand polymeric DNA fragments. We show that electronic wave-function localization, induced either by the native electrical dipole and/or by the electrostatic disorder originating from the first few water solvation layers, drastically suppresses the magnitude of the elastic conductance of A-DNA oligonucleotides. We then argue that electron transport through DNA is the result of sequence-specific short-range tunneling across a few bases combined with general diffusive/inelastic processes.