In vitro evaluation of cellular influences induced by stable fullerene C70 medium dispersion: Induction of cellular oxidative stress

Fullerene is one of the nanocarbons that is expected to have applications to life science, such as nanomedicines. An understanding of the cellular influences of fullerene is essential for its application to life science. Although C60 and C70 are both known as major fullerenes, most previous reports about the cellular influences of fullerene are about C60. Thus we evaluated the cellular influences caused by C70. A stable and uniform C70-medium dispersion was prepared. The dispersion was stable for the experimental period. Mitochondrial activity (MTT assay), colony forming ability (clonogenic assay), induction of oxidative stress (intracellular ROS and lipid peroxidation levels) and cellular uptake (TEM observation) in human keratinocyte HaCaT and lung carcinoma A549 cells exposed to C70 were examined. C70 did not influence mitochondrial activity. On the other hand, C70 dispersion inhibited colony formation at the concentration of 25.2 μg mL−1. Exposure to C70 dispersion caused an increase in intracellular ROS and lipid peroxidation levels. The induction of intracellular ROS level was inhibited by pre-treatment of the cells by antioxidants. TEM observations of C70 exposed cells showed cellular uptake of C70. These results were similar to the cellular influences caused by C60 which were reported by us previously. Although C70 did not cause cell death, it caused the induction of intracellular oxidative stress.