TiO2 as nanocarrier of antibiotics (quinolones): A molecular docking assay

Abstract

A QSAR study was carried out, by considering common quinolone to develop new chemical structures with possible antibacterial action. Furthermore, it has been performed a docking assay to get insight into the molecular interactions of the studied molecules herein with the biological target Staphylococcus aureus (S. aureus). On the other hand, a TiO₂ cluster was used as a nanocarrier model and was coupled to quinolones through a molecular docking assay. All the molecules were optimized using the density functional theory (DFT), with the functional M06L and a basis set 6-311+G(d,p); the molecular docking assay between isolated quinolone and the TiO₂-quinolone complex with DNA gyrase-topoisomerase IV (like biological target), was performed with Molegro Virtual Docker Software. The results show that the designed molecules present MIC (minimum inhibitory concentrations) values better than those of commercial drugs, especially when isatine and azole substituents were added. The molecular coupling of the designed structures mimics the linkage mechanism with the biological target, as has been reported in the literature. The addition of TiO₂ as a nanocarrier confers a better interaction than free drugs or free molecules due to the many target-ligand interactions. Finally, we can conclude that four potential antibiotics were designed, showing lower MIC values. Likewise, the TiO₂ nanocarrier promotes a better molecular coupling with the biological target, being our molecules a solid proposal to be synthesized and in vitro tested.