Synthesis and evaluation of the antimicrobial potentials of cobalt doped- and magnesium ferrite spinel nanoparticles

The high incidence of infectious disease and increase in the incidence of antibiotic resistance has led to the exploitation of inorganic nanoparticles as novel antimicrobial agents owing to their unique physical and chemical properties. This study reports the synthesis and antibacterial activity of magnesium ferrite (Mg[Fe.sub.2][O.sub.4]) and cobalt doped magnesium ferrite ([Co.sub.0.8][Mg.sub.0.2][Fe.sub.2][O.sub.4]) spinel nanoparticles (NPs). The NPs were synthesized using the low temperature combustion synthesis. X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive absorption spectroscopy (EDAX) were used to characterize the synthesized NPs. The synthesized NPs exhibited good antibacterial properties against Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus and Serratia marcescens. None of the nanoparticles induced any microbial inhibition against Micrococcus varians, Aspergillus flavus, Bacillus substilis and Candida. albicans. [Co.sub.0.8][Mg.sub.0.2][Fe.sub.2][O.sub.4] NPs gave better antibacterial activity with a zone of inhibition of >20 mm against Staphylococcus aureus and Escherichia coli compared to Mg[Fe.sub.2][O.sub.4] NPs. The minimum inhibitory concentration of [Co.sub.0.8][Mg.sub.0.2][Fe.sub.2][O.sub.4] NPs against Escherichia coli and Staphylococcus aureus was 2500 [mu]g/mL and 1250 [mu]g/mL, respectively. The relatively high antibacterial effect exhibited by [Co.sub.0.8][Mg.sub.0.2][Fe.sub.2][O.sub.4] nanoparticles on Escherichia coli and Staphylococcus aureus suggests its potentials in the treatment of infections commonly associated with these microorganisms.KEY WORDS: Magnesium ferrite, Nanoparticles, Antibacterial activity, Combustion synthesis, Infectious disease