In vitro and in vivo genotoxicity tests on fullerene C60 nanoparticles

There are several conflicting reports on the genotoxicity of fullerene C60 in the literature. To determine the genotoxic potential of C60 nanoparticles, we prepared stable nano-sized C60 suspensions using 0.1% carboxymethylcellulose sodium (CMC-Na) or 0.1% Tween 80 aqueous solution. We conducted a bacterial reverse mutation test with Ames Salmonella typhimurium TA98, TA100, TA1535, and TA1537 strains and Escherichia coli strain and a chromosomal aberration test with cultured Chinese hamster CHL/IU cells in the presence and absence of metabolic activation under dark conditions and visible light irradiation using a stable C60 nanoparticle suspension with CMC-Na. In addition, we performed a bone marrow micronucleus test using a stable C60 nanoparticle suspension with Tween 80 on ICR mice. C60 nanoparticles did not show a positive mutagenic response up to the maximum dose of 1000 μg/plate with any tester strain in the bacterial reverse mutation test regardless of metabolic activation and irradiation, although a slight but not significant increase in the number of revertants was observed in TA100 and WP2 uvrA/pKM101. No increase in the incidence of chromosomal aberrations was observed at any C60 nanoparticle dose regardless of metabolic activation and irradiation in the chromosomal aberration test up to the maximum doses of 100 and 200 μg/mL. In addition, the micronucleus test showed that the in vivo clastogenic ability of the C60 nanoparticles was negative up to the maximum dose of 88 mg/kg × 2. Therefore, we concluded that the stable and well-characterized C60 nanoparticles did not have genotoxic ability in the bacterial reverse mutation assay, in vitro chromosome aberration assay, nor in vivo micronucleus assay.