Figure 6.

Measurement of MMP and ATP in HEK293 cells. (A) HEK293 cells were treated with various concentrations of graphene oxide for 24 h. Changes in MMP were then determined using a cationic fluorescent dye, JC-1. (B) ATP levels were measured according to the manufacturer’s instructions (Sigma-Aldrich; Catalog Number MAK135) in HEK293 cells exposed to graphene oxide for 24 h. The results are expressed as the means ± standard deviation of three independent experiments. There were significant differences in the ratios of MMP and ATP production in graphene oxide-treated cells compared to untreated cells. *p < 0.05 was considered significant; **p < 0.01 was considered highly significant and ***p < 0.001 was considered very highly significant.