Induced temperature-dependent DNA degradation by C 60 without photoactivation

Abstract

This study shows that C 60 can degrade pBR322 plasmid DNA at room temperature without photoactivation. The degradation was enhanced by increasing incubation temperature, reaction time or C 60 concentration. We also found that superoxide radical anions 2-· were formed in the C 60 solution. Superoxide dismutase significantly inhibited DNA cleavage and O 2-· generation induced by C 60. These results suggest that DNA cleavage was caused by the formation of reactive oxygen species induced by C 60 at room temperature. Furthermore, we demonstrate that the DNA degradation was significantly inhibited by acid amide chemicals such as formamide, and by increased ionic strength of the reaction solution. These results indicate that the DNA conformation stability and the surface properties of C 60 are important factors regulating DNA degradation. We propose that C 60 can bind DNA, decrease DNA conformation stability, and induce the formation of reactive oxygen species and DNA cleavage at room temperature. Our results provide a possible explanation for the genotoxicity of C 60, which should be considered in future use of this particular nano-material. © The Author(s) 2011.