Sono-synthesis and characterization of next-generation antimicrobial ZnO/TiO2 and Fe3O4/TiO2 bi-nanocomposites, for antibacterial and antifungal applications

ABSTRACT Ultrasonic-assisted synthesis of ZnO/TiO₂ and Fe₃O₄/TiO₂ bi-oxide-nanocomposites at low-frequencies (60kHz) with their characterizations, and antibacterial/antifungal applications are investigated in this study. Using nanotechnology as the next-generation solution, this research looked into the possibility of metal oxide nanoparticles as effective antibacterial agents. Nanomaterials were synthesized via a facile method (sono-synthesis) and characterized using a series of techniques (XRD, SEM, FTIR, zeta potential analysis, Raman spectroscopy, and XPS), revealing nanoscale sizes of 25 nm for ZnO/TiO₂ and 31 nm for Fe₃O₄/TiO₂. Structural analysis demonstrated the distinct crystalline phases of the synthesized nanomaterials: TiO₂ with anatase structure (25%), hexagonal wurtzite structure for ZnO, and Fe₃O₄ with inverse spinel structure, formed in nano-dimensions (19-31 nm) with a near-spherical shape. Antibacterial and antifungal assays highlighted the efficacy of both nanocomposites against gram-positive (<i>Staphylococcus aureus</i>) and gram-negative (<i>Escherichia coli </i>and<i> Pseudomonas aeruginosa</i>) bacteria, along with their potent activity against <i>Candida albicans </i>and non-<i>albicans Candida</i>. In addition, principal component analysis (PCA) was used to identify potential relationships between the physicochemical properties (Zeta potential, size, conductivity, and concentration) of all nanomaterials tested and their zone of inhibition (ZOI) against all bacterial species. Overall, this study underscores the pivotal role of nanotechnology in enhancing antimicrobial efficacy, materialized by a simple and efficient sono-synthetic route for the fabrication of ZnO/TiO₂ and Fe₃O₄/TiO₂ Bi-nanocomposites and their application in antibacterial and antifungal tests.