title: Critical factors to be considered when testing nanomaterials for genotoxicity with the comet assay.
abstract: The comet assay is widely used to test the genotoxicity of engineered nanomaterials (ENMs) but outcomes may vary when results from different laboratories, or even within one laboratory, are compared. We address some basic methodological considerations, such as the importance of carrying out physico-chemical characterisation of the ENMs in test-medium, performing uptake and cytotoxicity tests, and testing several genotoxicity-related endpoints. In this commentary, we discuss the different ways in which concentration of ENMs can be expressed, and stress the need to include appropriate controls and reference standards to monitor variation and avoid interference. Treatment conditions, including cell number, cell culture plate format and volume of treatment medium on the plate are crucial factors that may impact on results and thus should be kept constant within the study.
authors.affiliation: Health Effects Laboratory, Department of Environmental Chemistry, NILU-Norwegian Institute for Air Research, Instituttveien 18, 2007 Kjeller, Norway.
authors.forename: Anna
authors.initials: A
authors.lastname: Huk
authors.affiliation: Department of Nutrition, University of Oslo, Sognsvannsveien 9, 0372 Oslo, Norway.
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Collins
authors.affiliation: Health Effects Laboratory, Department of Environmental Chemistry, NILU-Norwegian Institute for Air Research, Instituttveien 18, 2007 Kjeller, Norway, Department of Nutrition, University of Oslo, Sognsvannsveien 9, 0372 Oslo, Norway.
authors.forename: Naouale
authors.initials: N
authors.lastname: El Yamani
authors.affiliation: Unit of Experimental Toxicology and Ecotoxicology (UTOX-CERETOX), Barcelona Science Park, Parc Científic de Barcelona c/ Baldiri Reixac, 10-12, Edifici Cluster, 08028 Barcelona, Spain.
authors.forename: Constanca
authors.initials: C
authors.lastname: Porredon
authors.affiliation: Department of Pharmacology and Toxicology, Faculty of Pharmacy, University of Navarra, C/Irunlarrea 1, 31009 Pamplona, Spain.
authors.forename: Amaya
authors.initials: A
authors.lastname: Azqueta
authors.affiliation: Unit of Experimental Toxicology and Ecotoxicology (UTOX-CERETOX), Barcelona Science Park, Parc Científic de Barcelona c/ Baldiri Reixac, 10-12, Edifici Cluster, 08028 Barcelona, Spain.
authors.forename: Joaquín
authors.initials: J
authors.lastname: de Lapuente
authors.affiliation: Health Effects Laboratory, Department of Environmental Chemistry, NILU-Norwegian Institute for Air Research, Instituttveien 18, 2007 Kjeller, Norway, mdu@nilu.no.
authors.forename: Maria
authors.initials: M
authors.lastname: Dusinska
mesh_terms: D020552:Comet Assay / Q000379:methods*; D004249:DNA Damage / Q000235:genetics*; D049329:Nanostructures / Q000633:toxicity*; D015203:Reproducibility of Results