Fig. 4. Cellular uptake of NPs in the 4T1 cells. (A) Fluorescence microscopic images of 4T1 cells after incubation for 3 h with free C6 and C6-NPs. C6 were green and the nuclei were stained with DAPI (blue). (B and C) Mean fluorescence intensity analysis by FCM. (D) Fluorescence microscopic images of the 4T1 cells for determining cellular uptake kinetics of C6-NPs at different time points. (E and F) Mean fluorescence intensity analysis of cellular uptake kinetics by FCM.