Figure 2.

Effects of graphene oxide on the viability and proliferation of HEK293 cells. (A) The viability of HEK293 cells was determined by a CCK-8 assay after 24 h of exposure to different concentrations of graphene oxide. (B) Cell proliferation was assessed using a BrdU cell proliferation assay. The results are expressed as the means ± standard deviation of three independent experiments. A significant difference was observed between treated and untreated cells. *p < 0.05 was considered significant; **p < 0.01 was considered highly significant and ***p < 0.001 was considered very highly significant.