Enhanced antibacterial efficacy of biocompatible Ag-doped ZnO/AgO/TiO2 nanocomposites against multiresistant bacteria

Nanoparticles with bactericidal properties offer significant advantages, and their integration with other nanomaterials can further enhance these benefits. This study investigates the synergistic effects of Ag-doped ZnO/AgO (ZnAg) nanocomposites combined with TiO 2 nanocrystals (NCs) as antibacterial agents while assessing their in vitro and in vivo nanotoxicity. Three distinct compositions (25Ti/75ZnAg, 50Ti/50ZnAg, and 75Ti/25ZnAg) were evaluated for their combined effects. Characterization through X-ray diffraction (XRD) and scanning electron microscopy (SEM) confirmed the successful synthesis of nanocomposites with well-dispersed NCs in the desired ratios. Morphological analysis revealed spherical TiO 2 NCs, rod- and plate-shaped Ag-doped ZnO, and spherical AgO particles. The 50Ti/50ZnAg nanocomposite exhibited superior photocatalytic activity in degrading methylene blue (MB) compared to pure ZnAg and TiO 2 . In nanotoxicology assessments, except Ag-doped ZnO, the nanocomposites demonstrated good biocompatibility with human peripheral blood mononuclear cells (PBMCs) at concentrations below 100 µg/mL. In Drosophila melanogaster assays, no toxic effects were observed at lower concentrations. Additionally, the nanocomposites effectively inhibited bacterial growth, particularly against antibiotic-resistant strains such as MRSA and KPC, by generating reactive oxygen species (ROS) and disrupting bacterial biofilm formation. Ti/ZnAg nanocomposites exhibited enhanced photocatalytic properties, biocompatibility, and antimicrobial activity, particularly against antibiotic-resistant strains.