Computational Insights into DNA Nucleobase-Silver Nanocluster Interactions: A Density Functional Theory Approach to Stability, Solvent Effects, and Bandgap Variation

This research explores the interactions between silver nanoparticles and DNA nucleobase monomers by means of Density Functional Theory (DFT) analysis for future applications in drug delivery. Molecular structures of nucleobases were optimized at B3LYP/6-311G level, whereas silver nanoclusters were optimized by applying the B3LYP/LANL2DZ basis set in keeping planar conformations. Binding and interaction energies were evaluated under normal conditions in both polar (chloroform, water) and nonpolar (cyclohexane) solvent conditions. Results indicate that silver cluster size enlargement improves nucleobase binding via hydrogen bonding and polarization interactions. Of the configurations investigated, the six-atom silver nanocluster was found to be most stable and had the lowest bandgap, thus being a viable candidate for bio-nanoconjugates. Water was discovered to be the best medium for solubility, further attesting to its applicability in biological compatibility. These results give computational evidence for the structural and electronic properties of DNA–AgNP systems, providing a foundational platform for future nanocarrier designs in gene sequencing, biosensing, and targeted drug delivery platforms.