Theoretical multiscale study on the properties, aqueous solution behavior and biological impact of zinc oxide nanoparticles

The aim of this theoretical study is to describe the relationship between the structure and the physicochemical properties of zinc oxide nanoparticles (ZnO NPs) and Mn doped ZnO NPs to assess their toxicological impact. In order to do so, a multiscale modelling approach is applied. Different nanoparticles, as well as the mechanism(s) of nanoparticle aggregation and growing, are characterized in terms of size and shape considering electronic, surface, structural and topological properties via quantum mechanics simulations. To evaluate the toxicology impact of ZnO NPs in human health safety and their possible environmental impact, classical molecular dynamics simulations were carried out to study the interaction between the nanomaterials and biological target systems: a set of selected human proteins and model plasma membranes. Likewise, the simulation of nanoparticles dispersion in aqueous media along with water adsorption on their surfaces was conducted. The mayor findings may be summarized as: i) the ZnO NPs from 12 to 96 (ZnO) units are characterized and their interaction energies, HOMO-LUMO gaps, superficial areas and volumes are reported; ii) the (ZnO)12 NP and Zn11MnO12 NP are further characterized via their topological properties, vibrational spectra, PDOS and non-covalent interactions; iii) the doping with Mn atoms is favourable. The interaction energies, HOMO-LUMO orbitals and gaps, PDOS, atomic charges, superficial areas and volumes are reported for NPs doped with up to 5 Mn atoms; iv) high water affinity for ZnO NPs is reported with both quantum and classical calculations, v) (ZnO)12 NPs do not penetrate the cell membrane and vi) the affinity energy of both ZnO and Mn doped NPs for human proteins is moderate. The reported results provide in-depth whole-chain studies of zinc oxide nanoparticles, which have been successfully applied for different technologies.