Research on the Electrical Properties of Drug‐DNA Complexes Takes Into Account Na ⁺ Ions and the Solvent Environment

ABSTRACT

Counterions and the solvent environment are critical factors determining the electrical properties of DNA. Previous studies have reported the effects of Na ⁺ ion concentration variations and solvent environments on the electrical conductivity of B‐DNA. However, the mechanism by which they exert their influence on the drug‐DNA complex remains unclear. This model integrates density functional theory and the nonequilibrium Green's function formalism to explore the impact of Na ⁺ ions on the electrical properties of three drug‐DNA complexes in both aqueous and vacuum environments. By minimizing the energy, Na ⁺ ions are added to the drug‐DNA complexes to render them electrically neutral. Subsequently, the electrical properties of the three DNA molecules are calculated under neutral conditions and after randomly removing one Na ⁺ ion in different solvent environments to investigate the effects of the solvent environment and Na ⁺ ions. The results show that the presence of Na ⁺ hinders charge transport at the HOMO level both in aqueous solvent and vacuum. The removal of one Na ⁺ ion from each of the three complexes leads to an increase in molecular conductivity and charge transfer efficiency, among which the Noga‐DNA complex is particularly significantly affected by Na ⁺ ions in the aqueous environment.