Cellular uptake showing comparison of intracellular fluorescence of doxorubicin: Incubation of MDAMB231 cells with different doxorubicin formulations (1 µM) for 2 h is shown by (a) Confocal microscopy images showing intracellular fluorescence of doxorubicin (b) Flow cytometry histograms showing intensity of uptake (c) Comparison of uptake efficiency by intensity of doxorubicin fluorescence.