In vitro evaluation of cellular responses induced by stable fullerene C60 medium dispersion

Because of the expansion of the functionalities available for modification of fullerene C-60 and its derivatives, their uses are increasing. However, the consequences of fullerene exposure to human health have not been fully studied. In vitro experiments are useful for risk assessment and for understanding potential applications. However, the insolubility of pristine C-60 in water makes the in vitro evaluation of cellular responses difficult. To overcome this problem, we prepared a stable and uniform C-60-medium dispersion for in vitro examinations. In addition, we examined the effect of the C-60-medium dispersion on human keratinocyte HaCaT cells and human lung carcinoma A549 cells to understand the cellular responses induced by exposure to C-60. Results indicated that exposure to C-60 did not affect cell viability; neither apoptosis nor necrosis were induced, while cell proliferation was inhibited. Furthermore, intracellular oxidative stress was induced by C-60 exposure in both HaCaT and A549 cells. Transmission electron microscopy indicated the cellular uptake of C-60 aggregates. The results obtained from this study indicate that C-60 has oxidative stress induction potential. Further examinations including in vivo studies are necessary for a more accurate evaluation of biological influences by C-60.