title: Antimicrobial and Genotoxicity Effects of Zero-valent Iron Nanoparticles.
abstract: BACKGROUND
  In a world of nanotechnology, the first concern is the potential environmental impact of nanoparticles. An efficient way to estimate nanotoxicity is to monitor the responses of bacteria exposed to these particles.
  
  
  OBJECTIVE
  The current study explored the antimicrobial properties of nZVI (zero-valent Iron nanoparticles) on the Gram-negative bacterial systems Erwinia amylovora, Xanthomonas oryzae and the Gram-positive bacterial systems Bacillus cereus and Streptomyces spp. The genotoxicity potential of nZVI was also assayed.
  
  
  METHODS
  THE TOXICITY OF NZVI WAS TESTED BY TWO DIFFERENT METHODS: Growing bacteria in liquid (broth dilution) and agar media (challenge test) containing different nZVI concentrations for 24-72 hours. The genotoxicity of nZVI was assessed using the preincubation version of the Ames test.
  
  
  RESULTS
  The lowest concentrations of nZVI that inhibited the visible growth (MIC) of E. amylovora, X. oryzae, B. cereus and Streptomyces spp. were 625, 550, 1250 and 1280 ppm, respectively. The minimum bactericidal concentration (MBC) for E. amylovora and X. oryzae were 10,000 and 5,000 ppm of nZVI, respectively. MBC was not observed for the Gram positive bacteria. No bacteriostatic and bactericidal effects were observed for oxidized nZVI. Mutant frequency did not increase according to the vehicle control at the concentrations assayed, indicating a lack of mutagenicity associated with nZVI.
  
  
  CONCLUSIONS
  nZVI nanoparticles are not mutagenic at low concentrations, therefore they can be used without detrimental effects on soil bacteria.
authors.affiliation: Department of Microbiology, Faculty of Science, Urmia Azad University, Urmia, IR Iran.
authors.forename: Elham
authors.initials: E
authors.lastname: Barzan
authors.affiliation: Department of Cell and Molecular Biology, Faculty of Biological Sciences, Kharazmi University, Tehran, IR Iran.
authors.forename: Sedigheh
authors.initials: S
authors.lastname: Mehrabian
authors.affiliation: Department of Cell and Molecular Biology, Faculty of Biological Sciences, Kharazmi University, Tehran, IR Iran.
authors.forename: Saeed
authors.initials: S
authors.lastname: Irian
keywords: Bronchial Provocation Tests; Mutagenicity; Nanoparticles