Figure 6: Fluorescence microscope images of MDA-MB-231 cells after co-incubation with free DOX, Dex-MBA-PAA-DOX NGs and Dex-SS-PAA-DOX NGs for 12 or 48 h at an equivalent DOX concentration of 15 μg/mL, the red colour corresponds to the fluorescence of DOX, the blue colour corresponds to the fluorescence of DAPI (a cell nucleus dye).

Scale bars: 100 μm.