The ability of gold nanoclusters as a new nanocarrier for D-penicillamine anticancer drug: a computational chemistry study

Abstract

In this work, we study the interactions between gold nanocluster (AunNCs, n = 2, 4, and 6) and D-penicillamine (DPA) anticancer drug by different computational methods to study the ability of AunNCs to act as a nanocarrier for DPA for the first time. We calculated the binding energies of all AunNCs-DPA complexes in the gas and water phases by density functional theory. The binding energies calculated by two different functionals, B3LYP and M062X, of the AunNCs-DPA complexes in the solvent phase are lower than those in the gas phase, suggesting that the partially covalent and partially electrostatic bonding stabilizes the complexes. Atoms-in-molecules analysis showed that the intermolecular hydrogen and covalent bonding play an important role in the formation of these complexes. The interactions between AunNCs-DPA complexes and water molecules also were studied by molecular dynamics simulations to summarize the effect of solvent on the binding between AunNCs and DPA. Radial distribution functions and coordination numbers of the interactions between AunNCs-DPA complexes and water are computed and showed that Au6NCs has the strongest interactions with DPA with compared to other complexes. The adsorption and deformation energies of DPA molecules on AuNCs surface has a 6 nm size with different shapes (sphere and box) and are calculated by MC simulations; the adsorption energies for all configurations in sphere and box shapes are negative which revealed that the adsorption of the drug molecule is exothermic and energetically favorable, and this indicated that the adsorption of DPA on the AuNPs surface is spontaneous due to existence of the weak intermolecular interaction. So, the drug molecule can be easily released from AunNPs.