E. coli are a large and diverse group of bacteria. Most species are harmless and usually inhabit human and animal gut of healthy people. Some serotypes are instead pathogenic and are able to cause bloody diarrhea, kidney failure and even death. Common conveying pathways of E. coli are undercooked ground beef, raw milk, juice, fruit, vegetables as well as contaminated water. Single oxides nanoparticles, expecially CuO and ZnO, proved to be an efficient tool to reduce E. coli concentration in water1. Here we present the enhanced effects of synthesized nanosized mixed Cu/Zn and Cu/Zn/Co oxides against E. coli in water. The mixed oxides were synthesized from hydroxycarbonates precursors and fully characterized by XRD, IR and SEM, hence their structure and size were determined. Afterwards, the nanoparticles were dispersed thoroughly in a culture medium and E. coli bacteria were cultivated on Tryptic Soy Agar plated containing different concentrations of metal oxides nanoparticles (50-100-200-400 mg/ml). Bacteria were counted in terms of colony forming units (CFU). E. coli counts decreased in the culture medium containing metal oxide nanoparticles and the dose-response relationship was calculated. In general, all mixed oxides display better performances as compared to the corresponding single oxides. Furthermore, the ternary mixed oxide Cu/Zn/Co oxides nanoparticles display a higher biocidal power than the binary Cu/Zn ones. Tests were performed also in comparison with single oxides mechanically mixed in the same proportion of the solid solutions of mixed oxides, with systematic lower performances. The bacterial inhibition rate increases linearly with the concentration of nanoparticles, the highest viability reduction values (>99%) being obtained at the highest doses. Cytotoxicity tests were performed on the single, binary and ternary oxide which displayed the highest biocidal power and revealed a level of toxicity comparable for all the nanoparticles, regardless of their composition.
Enhanced biocide power of Cu/Zn/Co mixed oxides towards E.coli
EM Bauer;
2017
Abstract
E. coli are a large and diverse group of bacteria. Most species are harmless and usually inhabit human and animal gut of healthy people. Some serotypes are instead pathogenic and are able to cause bloody diarrhea, kidney failure and even death. Common conveying pathways of E. coli are undercooked ground beef, raw milk, juice, fruit, vegetables as well as contaminated water. Single oxides nanoparticles, expecially CuO and ZnO, proved to be an efficient tool to reduce E. coli concentration in water1. Here we present the enhanced effects of synthesized nanosized mixed Cu/Zn and Cu/Zn/Co oxides against E. coli in water. The mixed oxides were synthesized from hydroxycarbonates precursors and fully characterized by XRD, IR and SEM, hence their structure and size were determined. Afterwards, the nanoparticles were dispersed thoroughly in a culture medium and E. coli bacteria were cultivated on Tryptic Soy Agar plated containing different concentrations of metal oxides nanoparticles (50-100-200-400 mg/ml). Bacteria were counted in terms of colony forming units (CFU). E. coli counts decreased in the culture medium containing metal oxide nanoparticles and the dose-response relationship was calculated. In general, all mixed oxides display better performances as compared to the corresponding single oxides. Furthermore, the ternary mixed oxide Cu/Zn/Co oxides nanoparticles display a higher biocidal power than the binary Cu/Zn ones. Tests were performed also in comparison with single oxides mechanically mixed in the same proportion of the solid solutions of mixed oxides, with systematic lower performances. The bacterial inhibition rate increases linearly with the concentration of nanoparticles, the highest viability reduction values (>99%) being obtained at the highest doses. Cytotoxicity tests were performed on the single, binary and ternary oxide which displayed the highest biocidal power and revealed a level of toxicity comparable for all the nanoparticles, regardless of their composition.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
