  In this work, we report a novel strategy to construct molecular diodes with a
record tunable rectification ratio of as high as 10^6 using oxidatively damaged
DNA molecules. Being exposed to several endogenous and exogenous events, DNA
suffers constant oxidative damages leading to oxidation of guanine to
8-Oxoguanine (8oxoG). Here, we study the charge migration properties of native
and oxidatively damaged DNA using a multiscale multiconfigurational methodology
comprising of molecular dynamics, density functional theory and kinetic Monte
Carlo simulations. We perform a comprehensive study to understand the effect of
different concentrations and locations of 8oxoG in a dsDNA sequence on its CT
properties and find tunable rectifier properties having potential applications
in molecular electronics such as molecular switches and molecular rectifiers.
We also discover the negative differential resistance properties of fully
oxidized Drew-Dickerson sequence. The presence of 8oxoG guanine leads to the
trapping of charge, thus operates as a charge sink, which reveals how oxidized
guanine saves the rest of the genome from further oxidative damage.
