Effect of Protonation on the electronic properties of DNA base pairs: Applications for molecular electronics

TL;DR

This study investigates how protonation affects the electronic properties of DNA base pairs, revealing potential applications in molecular electronics such as rectifiers and pH-dependent switches.

Contribution

It demonstrates that protonation induces rectification in A:T base pairs and enables pH-controlled switching in A:A base pairs, offering novel molecular electronic functionalities.

Findings

A:T basepair exhibits rectification under mild acidic conditions.

A:A basepair functions as an efficient pH-dependent molecular switch.

Protonation alters hydrogen bonding and electronic behavior of DNA base pairs.

Abstract

Protonation of DNA basepairs is a reversible phenomenon which can be controlled by tuning the pH of the system. Under mild acidic conditions, the hydrogen bonding pattern of the DNA basepairs undergoes a change. We study the effect of protonation on the electronic properties of the DNA basepairs to probe for possible molecular electronics applications. We find that, under mild acidic pH conditions, the A:T basepair shows excellent rectification behaviour which is, however, absent in the G:C basepair. The mechanism of rectification has been discussed using a simple chemical potential model. We also consider the non-canonical A:A basepair and find that it can be used as efficient pH dependent molecular switch. The switching action in A:A basepair is explained in the light of pi-pi interactions which lead to efficient delocalization over the entire basepair.