Toxicity of Ce₂O₃/TiO₂ composite nanofibers against S. aureus and S. typhimurium: A novel electrospun material for disinfection of food pathogens

This study presents the fabrication and characterization of novel cerium oxide-titanium dioxide (Ce₂O₃-TiO₂) composite nanofibers and their bactericidal activity. The utilized Ce₂O₃-TiO₂ nanofibers were prepared by electrospinning of a sol-gel composed of cerium nitrate hexahydrate, titanium isopropoxide and poly(vinyl acetate). The physicochemical characterization of the synthesized composite nanofibers was carried out by X-ray diffraction pattern, field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, electron probe micro-analysis and transmission electron microscopy. The antibacterial activity was tested against two most common foodborne pathogenic bacteria such as Staphylococcus aureus (Gram-positive) and Salmonella typhimurium (Gram-negative). Bactericidal effects were determined by MIC measurements and transmission electron microscopy respectively. Our results suggested that the lowest concentration of Ce₂O₃-TiO₂ nanofibers which inhibits the growth of tested strains was found to be 10μg/ml. TEM analysis demonstrated that the exposure of pathogenic strains to the electrospun nanofibers leads to disruption of cell membranes which cause bacteria to die eventually. Moreover, the current results showed superior antimicrobial action of Ce₂O₃-TiO₂ than pristine TiO₂ nanofibers which might be due to the obvious impact of Ce₂O₃ doping into TiO₂. In conclusion, novel Ce(III) oxide-titania nanofibers which possess a large surface volume were fabricated as a microbial growth inhibitor with excellent antimicrobial activity.