[Cytotoxicity of fullerene (60), carbon nanotube, and their derivatives in V79 cells and cultured normal human astrocytes].

Fullerenes are a family of carbon allotropes, molecules composed entirely of carbon. Fullerenes have been developed in various forms and functions and are expected to be used for novel medical materials targeting on brain. Information on cytotoxicity of fullerenes on brain function, however, is few; thus we examined the effect of fullerenes on the brain astrocytes in this study. We used fullerene [60], hydroxylated-fullerene [60], carboxylated-fullerene [60], dimalonilated-fullerene [60], carboxylated-carbon nanotube and amino-carbon nanotube. At first, we examined cytotoxicity of fullerenes by V79 colony assay. Fullerenes inhibited the cell growth in a concentration-dependent manner, but 50 percent growth inhibition concentrations were different among fullerene derivatives, which we used. Cytotoxicity of carbon nanotubes was stronger than that of fullerenes. Secondly, we performed the microtiter tetrazolium assay of normal human astrocytes and measured the effects of fullerenes on cell activity. Fullerenes and carbon nanotubes decreased mitochondrial activity. In addition to this, it was observed that fullerenes and nanotubes adhered to cells. These results suggest that fullerenes and carbon nanotubes have cytotoxicity and the effects are different from each other due to their side chain and steric forms. We expected that fullerenes and carbon nanotubes gave physical stress to cells and caused cytotoxicity. In conclusion, it was suggested that safety evaluation is needed for fullerenes and carbon nanotubes individually.