Effect of ZnO nanoparticles on growth and light emission of Vibrio fischeri

Abstract

Background and Aim:As ZnO is increasingly used in antibacterial applications, there is an urgent need for<br><br>information on safety and potential hazards of manufactured NPs. One of the widely used tests in<br><br>ecotoxicology to predicting the toxicity of chemicals is the Vibrio Escheri luminescence inhibition assay.In<br><br>this study to find out how much safe is our laboratory made ZnO NPs, its inhibitory effect on bacterial growth<br><br>and luminescent light output of Vibrio Escheri strain NRRLB-B1177 has been investigated.<br><br>Methods:ZnO NPs synthesized by solvothermal method and dispersed in glycerol, as base fluid by the means<br><br>of ammonium citrate.Minimum inhibitory concentration (MIC) was determined by micro dilution assay using<br><br>ELISA reader apparatus. To investigate the side effects of ZnO NPs by bioluminescence inhibition assay and<br><br>determine effective concentration of ZnO NPs that decrease intensity of luminescence light production in<br><br>bacteria , several dilution of nanofluid inoculated in bacterial culture medium and then bacterial overnight<br><br>culture added to them. Bacterial growth and intensity of bioluminescence light in presence of several<br><br>concentrations of ZnO NPs measured by Berthold luminometer.<br><br>Results:MIC for ZnO nanofluid against Vibrio Escheri was 100 Zg/ml and in this concentration growth<br><br>inhibition percentage ( GI)% of ZnO NPs was 90%. Also effective concentration of ZnO NPs against bacteria<br><br>that decrease luminescence light intensity more than 50%, during the first 10 hours of bacterial growth was 1<br><br>Zg/ml. This concentration did not have any obvious effect on bacterial growth. In several other studies were<br><br>also used Vibrio fischeri, Vibrio harveyi and Pseudomonas fluorescens to determine luminescence inhibition<br><br>percentage under influence of particular agents with potential of toxicity.<br><br>Conclusion:ZnO NPs have antibacterial effect against V.fischeri. Toxic concentration became 100 fold lower<br><br>than the amount of antibacterial concentration. Similar to this investigation can be used to test toxicity of<br><br>several NPs or other chemicals.