Fabrication, Characterization, and Antibacterial Activity of Ferrite, Chromite, and Aluminate Nanoparticles

Zn _0.33 Co _0.33 Mg _0.33 X _2 O _4 nanoparticles (NPs), where X = Fe, Cr, Al and denoted by F, C, and A, were prepared by the co-precipitation method. X-ray diffraction patterns validated the formation of NPs with cubic spinel structure with the detection of small amounts of impurities in samples C (Cr _2 O _3 ) and A (MgO). Transmission electron micrographs showed a nearly spherical shape for samples F and A. However, sample C revealed cubic and nearly spherical shapes. Energy-dispersive x-ray analysis ensured the presence of chemical constituents in all samples. The vibrational modes of NPs were confirmed with Fourier transform infrared spectroscopy. The direct bandgap energy values, calculated using ultraviolet-visible spectroscopy, were in the range of 2.355 and 2.967 eV for F, C, and A samples. X-ray photoelectron spectroscopy analysis confirmed the compositions as well as the valence states of all elements. Magnetic hysteresis (M–H) loops revealed a soft ferromagnetic behavior. Sample F exhibited a higher saturation magnetization, remanent magnetization, magnetic moment, and magnetic anisotropy compared to those of samples C and A. The antibacterial activity of the tested samples against four bacteria ( Staphylococcus aureus, Stenotrophomonas maltophilia, Escherichia coli, and Enterococcus faecium ) was determined using the broth microdilution assay, minimum bactericidal concentration (MBC), and time-kill test. The prepared NPs exhibited varying antibacterial activity due to multiple factors. These results highlighted the potential utility of the ternary ferrite, chromite, and aluminate NPs in the treatment of microbial infections, particularly multidrug-resistant bacteria.