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

Ultrasonic-assisted synthesis of ZnO/TiO₂ and Fe₃O₄/TiO₂ bi-oxide nanocomposites at low frequencies (60 kHz) with their characterizations and antibacterial/antifungal applications are investigated in this study. Using nanotechnology as the next-generation solution, this research explored the potential of metal oxide nanoparticles as effective antibacterial agents. Nanomaterials were synthesized via a novel and facile method (sono-synthesis) and characterized using various 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 bi-nanocomposites against gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacteria, along with their potent activity against Candida albicans and non-albicans Candida. Moreover, 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 tested. Overall, this study emphasizes the novelty of employing a simple and efficient sono-synthetic route to synthesize ZnO/TiO₂ and Fe₃O₄/TiO₂ bi-nanocomposites and investigate their significant antibacterial and antifungal activities. Additionally, it identifies the potential relationships between the physicochemical properties of the nanomaterials tested and their antimicrobial activity. This approach provides a robust framework for future applications of bi-nanocomposites in combating microbial infections. • Effectively synthesized Fe₃O₄, ZnO, Fe₃O₄/TiO₂, and ZnO–TiO₂ bi-nanocomposites using an ultrasonic process via one-pot synthesis, while also uncovering their inherent antimicrobial potential. • The sono-synthesized nanomaterials were characterized and confirmed by various spectroscopic and microscopic techniques. • XRD confirmed the successful synthesis of bi-nanocomposites and showed the average crystallite size of Fe₃O₄/TiO₂ as 15.79 nm and ZnO/TiO₂ as 10.35 nm. • Particularly, Fe₃O₄/TiO₂ and Fe₃O₄ showed significant antimicrobial activity against both Gram-negative and Gram-positive bacteria. • Both Fe₃O₄/TiO₂ and ZnO/TiO₂ bi-nanocomposites exhibited remarkable antibacterial activity against E. coli and antifungal activity against non-albicans Candida, suggesting their effectiveness in combating fungal pathogens. [ABSTRACT FROM AUTHOR]