Synthesis, Characterization, and Functional Analysis of Mixed Manganese/Cerium Oxide/Hydroxyapatite Nanocomposites for Antibacterial Applications

Mixed manganese/cerium oxide/hydroxyapatite composites are emerging as innovative materials with significant biomedical potential due to their antibacterial properties and biocompatibility. In this study, we synthesized mixed Mn/Ce oxide/HA composites using an ultrasonic-assisted sol-gel method, exploring their structural and functional characteristics through comprehensive analyses. Advanced characterization techniques, including X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), X-ray absorption spectroscopy (XAS), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and nitrogen adsorption-desorption isotherms, revealed a composite with enhanced structural stability and porosity, optimized for antibacterial applications. XRD confirmed the integration of a fluorite-structured CeO₂ phase with hexagonal hydroxyapatite, while FT-IR and XANES analyses verified the presence of functional phosphate groups and mixed oxidation states (Ce³⁺/Ce⁴⁺, Mn²⁺/Mn³⁺/Mn⁴⁺), essential for antibacterial efficacy. SEM imaging displayed a unique flake-like morphology conducive to clustering, and EDS confirmed elemental composition. Notably, nitrogen sorption isotherms revealed a marked increase in surface area from 2 m²/g in pure HA to 11–16 m²/g in Mn/Ce oxide/HA, which may enhance bacterial interaction. Antibacterial assays demonstrated potent activity against Bacillus cereus (B. cereus), Staphylococcus aureus (S. aureus), Staphylococcus epidermidis (S. epidermidis), Escherichia coli (E. coli), and Salmonella typhi (S. typhi), linked to reactive oxygen species production and bacterial membrane disruption. This study highlights the robust structural and antibacterial features of Mn/Ce oxide/HA composites, advancing their suitability for biomedical applications, particularly in infection-resistant materials and bone grafts.