The aim of this study was to investigate the effects of water soluble fullerene (fullerenol) nanoparticles on the in vitro genotoxicity induced by the insecticide acetamiprid. Healthy human lung cells (IMR-90) were treated with fullerenol C-60(OH)(n) (n: 18-22) alone and in combination with acetamiprid for 24 h. The micronucleus test, comet assay and gamma-H2AX foci formation assays were used as genotoxicity endpoints. Cytotoxicity was evaluated using the clonogenic assay. The maximum tested concentration of fullerenol (1.600 mu g/ml) induced 77% survival where as the lowest concentration (25 mu g/ml) was not cytotoxic where as acetamiprid was cytotoxic. Fullerenol did not induce genotoxicity at tested concentrations (50-1600 mu g/L). On the other hand, acetamiprid (>50 mu M) significantly induced formation of micronuclei, and double and single stranded DNA breaks in IMR-90 cells. For simultaneous exposure studies, two non-cytotoxic concentrations (50 and 200 mu g/ml) of fullerenol and three cytotoxic concentrations of acetamiprid (100, 200 and 400 mu M) were selected. As a result, we observed that co-exposure with fullerenol significantly reduced the cytotoxicity and genotoxicity of acetamiprid in IMR-90 cells. Our results indicated the protective effect of water soluble fullerene particles on herbicide induced genotoxicity. (C) 2014 Elsevier Inc. All rights reserved.