title: In vitro genotoxicity testing of four reference metal nanomaterials, titanium dioxide, zinc oxide, cerium oxide and silver: towards reliable hazard assessment.
abstract: There is serious concern about the potential harmful effects of certain nanomaterials (NMs), on account of their ability to penetrate cell membranes and the increased reactivity that results from their increased surface area compared with bulk chemicals. To assess the safety of NMs, reliable tests are needed. We have investigated the possible genotoxicity of four representative NMs, derived from titanium dioxide, zinc oxide, cerium oxide and silver, in two human cell lines, A549 alveolar epithelial cells and lymphoblastoid TK6 cells. A high-throughput version of the comet assay was used to measure DNA strand beaks (SBs) as well as oxidised purines (converted to breaks with the enzyme formamidopyrimidine DNA glycosylase). In parallel, cytotoxicity was measured with the alamarBlue® assay, and the ability of NM-treated cells to survive was assessed by their colony-forming efficiency. TiO2and CeO2NMs were only slightly cytotoxic by the alamarBlue® test, and had no long-term effect on colony-forming efficiency. However, both induced DNA damage at non-cytotoxic concentrations; the damage decreased from 3 to 24-h exposure, except in the case of CeO2-treated A549 cells. ZnO and Ag NMs affected cell survival, and induced high levels of DNA damage at cytotoxic concentrations. At lower concentrations, there was significant damage, which tended to persist over 24 h. The implication is that all four reference metal NMs tested-whether cytotoxic or not-are genotoxic. A full assessment of NM toxicity should include tests on different cell types, different times of incubation and a wide range of (especially non-cytotoxic) concentrations; a test for cell viability should be performed in parallel. Inclusion of Fpg in the comet assay allows detection of indirect genotoxic effects via oxidative stress.
authors.affiliation: Health Effects Group, Department of Environmental Chemistry, NILU- Norwegian Institute for Air Research, Kjeller 2007, Norway.|Comet Biotech AS, Oslo 0372, Norway.
authors.forename: Naouale
authors.initials: N
authors.lastname: El Yamani
authors.affiliation: Comet Biotech AS, Oslo 0372, Norway.|Department of Nutrition, University of Oslo, Oslo 0372, Norway and.
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Collins
authors.affiliation: Health Effects Group, Department of Environmental Chemistry, NILU- Norwegian Institute for Air Research, Kjeller 2007, Norway.
authors.forename: Elise
authors.initials: E
authors.lastname: Rundén-Pran
authors.affiliation: Health Effects Group, Department of Environmental Chemistry, NILU- Norwegian Institute for Air Research, Kjeller 2007, Norway.
authors.forename: Lise Marie
authors.initials: LM
authors.lastname: Fjellsbø
authors.affiliation: Comet Biotech AS, Oslo 0372, Norway.
authors.forename: Sergey
authors.initials: S
authors.lastname: Shaposhnikov
authors.affiliation: STAMI-The National Institute of Occupational Health, Oslo 0363, Norway.
authors.forename: Shanbeh
authors.initials: S
authors.lastname: Zienolddiny
authors.affiliation: Health Effects Group, Department of Environmental Chemistry, NILU- Norwegian Institute for Air Research, Kjeller 2007, Norway, maria.dusinska@nilu.no.
authors.forename: Maria
authors.initials: M
authors.lastname: Dusinska
mesh_terms: D002460:Cell Line; D002470:Cell Survival; D020552:Comet Assay; D004247:DNA / Q000187:drug effects; D004249:DNA Damage; D043382:DNA-Formamidopyrimidine Glycosylase; D029968:Escherichia coli Proteins; D006801:Humans; D053768:Metal Nanoparticles / Q000633:toxicity*; D018384:Oxidative Stress / Q000187:drug effects
chemical_list: D029968:Escherichia coli Proteins; D004247:DNA; D043382:DNA-Formamidopyrimidine Glycosylase; C468610:DNA-formamidopyrimidine glycosylase, E coli