One dimensional Confinement of Electric Field and Humidity Dependent DNA Conductivity

TL;DR

This paper presents a theoretical study on how humidity influences DNA conductivity, highlighting the role of water layer thickness and electric field confinement in ionic transport, explaining a significant increase in conductivity with humidity.

Contribution

It introduces a model linking water layer thickness and electric field confinement to DNA conductivity changes due to humidity variations.

Findings

Conductivity increases by six orders of magnitude with humidity.

Water layer thickness critically affects ion binding energy.

Electric field confinement in water layers explains conductivity variation.

Abstract

The dependence of DNA assemblies conductance on relative humidity is investigated theoretically. Following earlier suggestions, we consider the ionic conductivity through the layers of water adsorbed by DNA molecules. The increase in humidity results in a growing water layer. The binding energy of ions depends on the thickness of the water layer due to change in water polarization. This dependence is very strong at smaller thicknesses of water layers due to the low-dimensional confinement of an electric field in water. We show that the associated change in ion concentration can explain the six orders of magnitude increase in conductivity, with relative humidity growing from 0.05 to 0.95