Synthesis and Characterization of Metal Ferrite Nanoparticles and their Bactericidal Efficacy against Xanthomonas Pathogens

Metal ferrite nanoparticles possess unique characteristics which allow for applications across a wide range of fields. Recently, these particles have been in the spotlight for their use as bactericidal control agents. The ability of stearate and cholate capped zinc and manganese ferrite nanoparticles to inhibit the growth of bacteria in the genus Xanthomonas was the primary investigation of this work. Both the zinc and manganese ferrite nanoparticles were synthesized using a pressure-assisted, heat mediated coprecipitation method in which surface functionalization and core formation occur in one step. The particles’ surfaces were functionalized with stearic and cholic acids, whose presence was confirmed using Fourier Transform Infrared Spectroscopy (FT-IR). Analysis of the particles’ crystal phase using powder X-ray diffraction (XRD) confirmed a single spinel phase in both the ZnFe2O4 and MnFe2O4 nanoparticles. Relative elemental analysis was performed using X-ray fluorescence (XRF) spectroscopy to confirm the presence of zinc and manganese in the particle materials. Transmission electron microscopy (TEM) revealed particles with semispherical morphologies and a mostly monodisperse size distribution with particle sizes < 10 nm. Dynamic Light Scattering (DLS) analysis of the particles revealed much larger hydrodynamic diameters, ranging from 108.4 nm to 581.2 nm, with evidence to suggest that the particles were agglomerating strongly in solution. The bactericidal results showed that the stearate and cholate-capped particles inhibited growth of several of the Xanthomonas test species, to varying degrees. While the results are not a clear indicator that the particles could be used as an alternative to traditional antibiotic treatments, due to issues with the tris dispersant used, they do suggest that the particles have potential for fulfilling this role.