Investigating adsorption of 5-fluorouracil and 6-mercaptopurine on icosahedral silver nanoparticles through DFT and TDDFT.

The favourable physicochemical properties and biocompatibility of silver nanoparticles (AgNPs) make them increasingly promising platforms for drug delivery. This study employs density functional theory (DFT) and time-dependent DFT (TDDFT) to investigate the adsorption of two anticancer drugs, 5-fluorouracil (FU) and 6-mercaptopurine (MP), on an icosahedral silver nanoparticle (AgNP). DFT was used to evaluate adsorption stability, electronic interactions, and charge transfer between the drugs and the silver surface. TDDFT simulations helped us understand how the optical absorption changes when the molecules attach. Both drugs exhibited strong and stable binding to the nanoparticle surface, with MP demonstrating a more pronounced interaction in terms of charge transfer and electronic coupling. Charge density difference maps and density of states analyses revealed significant interaction between the drugs and silver cluster. Additionally, the adsorption of the drugs led to noticeable modifications in the nanoparticle's plasmonic and interband optical features. These findings highlight the potential of AgNPs as effective and tuneable nanocarriers for anticancer drugs and offer valuable guidance for the design of advanced drug delivery systems in nanomedicine.