Rational Design for Building Blocks of DNA‐Based Conductive Nanowires through Multi‐Copper Incorporation into Mismatched Base Pairs

Abstract

Metal-modified DNA base pairs, which possess potential electrical conductivity and can serve as conductive nanomaterials, have recently attracted much attention. Inspired by our recent finding that multicopper incorporation into natural DNA base pairs could improve the electronic properties of base pairs, herein, we designed two novel multi-copper-mediated mismatched base pairs (G(3Cu)T and A(2Cu)C), and examined their structural and electronic properties by means of density functional theory calculations. The results reveal that these multi-Cu-mediated mismatched base pairs still have planar geometries that are thermodynamically favorable to stability, and their binding energies are close to those of multi-Cu-mediated normal base pairs (G(3Cu)C and A(2Cu)T). Their HOMO-LUMO gaps and ionization potentials decrease significantly compared to the corresponding natural base pairs. As evidenced by the charge transfer excitation transitions, transverse electronic communication of G(3Cu)T and A(2Cu)C is remarkably enhanced, suggesting that they facilitate electron migration along the DNA wires upon incorporation. Further examinations also clarify the possibility to build promising DNA helices using the G(3Cu)T and/or A(2Cu) C base pairs. The calculated electronic properties of the three-layer-stacked multi-Cu-mediated mismatched base pairs illustrate that the Cu(m)-DNA have better conductivity. This work provides perspectives for the development and application of DNA nanowires.