L: DNA damage induced by micro- and nanoparticles–interaction with FPG influences the detection of DNA oxidation in the comet assay

Reliable methods for evaluation of toxicity from particles, such as manufactured nanoparticles, are needed. One promising tool is the comet assay, often used to measure DNA breaks (strand breaks and alkali-labile sites) as well as oxidatively damaged DNA, the latter by addition of specific DNA repair enzymes such as formamidopyrimi-dine DNA glycosylase (FPG). The aim of this study was to investigate the use of the comet assay for analysis of DNA oxidation by a range of micro- and nanoparticles in the lung cell lines A549 and BEAS-2B and to test the hypothesis that nanoparticles present in the cells during the assay performance may interact with FPG. This was done by investigating the ability of micro- and nano-particles (stainless steel, subway particles, MnO2, Ag, CeO2, Co3O4, Fe3O4, NiO and SiO2) to induce DNA breaks