Figure 5
Induction of DNA strand breaks by CuO NP, CuO MP or CuCl 2 in the absence and presence of H 2 O 2 . Logarithmically growing HeLa S3 cells were preincubated with CuO NP, CuO MP or CuCl2 for 24 h alone (A) or in combination with 35 μM H2O2(B) for 5 minutes in the continued presence of CuO NP, CuO MP or CuCl2. DNA strand breaks were quantified by Alkaline Unwinding as described in Materials and methods. The data represent mean values of 3 determinations + SD. Statistically significant different from control (A) or from H2O2-treated cells in the absence of copper compounds (B): *p < 0.05, **p < 0.01, ***p < 0.001 as determined by unifactorial analyis of variance (ANOVA) followed by Dunnet's T3 test. 1 μg/mL are equal to 0.2 μg/cm2 and 20 μg/mL CuO are equal to 252 μM Cu2+ in case of complete dissolution.