Mutagenesis Advance Access originally published online on May 25, 2008
Mutagenesis 2008 23(5):377-382; doi:10.1093/mutage/gen024
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Comparative genotoxicity of cobalt nanoparticles and ions on human peripheral leukocytes in vitro
1Department of Human and Environmental Sciences, Faculty of Medicine, University of Pisa, Via S. Giuseppe 22, 56100 Pisa, Italy 2ECVAM Unit, European Commission, DG-Joint Research Centre, Institute of Health and Consumer Protection, Via E. Fermi 1, 21020 Ispra (VA), Italy 3Department of Medical Clinic, Nephrology and Prevention Sciences, Section of Labour Medicine, University of Parma, Viale Gramsci 14, 43100 Parma, Italy
Owing to the increasing development of nanotechnology, there is a need to assess how engineered nanomaterials can interact with living cells. The main purpose of the present study was to assess whether metal cobalt nanoparticles (CoNP 100–500 nm) are genotoxic compared to cobalt ions (Co2+). Uptake experiments were carried out by incubating peripheral blood leukocytes (PBLs) with 57Co2+ (added to stable Co2+ 10–2 M to obtain concentrations in the range of 10–5 to 10–4 M) or with 60CoNP for 24 and 48 h. Whereas intracellular Co2+ showed slight or no variations over the baseline levels, CoNP were taken up efficiently leading to intracellular CoNP concentrations of 485 ± 106.1 and 970 ± 99 fg per cell after 24 and 48 h, respectively. The genotoxicity end points considered in this study were the frequency of binucleated micronucleated (BNMN) cells and the percentage of tail DNA (% Tail DNA) fragmentation by means of the comet assay. Genotoxic effects were evaluated by incubating PBLs of three healthy donors with subtoxic concentrations (10–5 to 8 x 10–5M) of Co2+ in the form of cobalt chloride, CoNP and ‘washed’ CoNP, the latter to exclude any interference by Co2+. On a group basis, Co2+ induced a clear trend in the increase of the BNMN frequency, whereas CoNP showed only minor changes. Moreover, we observed a high variability among donors in the induction of micronuclei. The comet assay showed a statistically significant dose-related increase in % Tail DNA for CoNP (P < 0,001), whereas Co2+ did not induce significant changes over control values. These findings suggest that nanosized Co can be internalized by human leukocytes and can interact with DNA leading to the observed genotoxic effects, which are, however, modulated both by donor's characteristics and/or by Co2+ release.
* To whom correspondence should be addressed. Dipartimento di Scienze dell'Uomo e dell'Ambiente, Università di Pisa, Via S. Giuseppe 22, 56126 Pisa, Italy. Tel: +39 0502211029; Fax: +39 050551290; Email: l.migliore{at}geog.unipi.it
4 Present address: NMI Unit, European Commission, DG-Joint Research Centre, Institute of Health and Consumer Protection, TP 203, Via E. Fermi 1, 21020 Ispra (VA), Italy
Received on December 20, 2007; revised on April 14, 2008; accepted on April 14, 2008.