Fig. 4. In vitro experiments with HM, H-HM@BSA and DH-HM@BSA. (a) In vitro cytotoxicity of HM: CCK-8 results for the MCF-7 human breast cancer cells co-incubated with HM at different concentrations. (b) Confocal images of the uptake of DH-HM@BSA by the MCF-7 cells at various time points (red, green, and blue represent emissions from HMME, DOX, and DAPI, respectively). (c) Confocal images of the uptake of free DOX & HMME and DH-HM@BSA by the MCF-7 cells at 1 h (white scale bars denote 36.8 μm). (d) CCK-8 results for MCF-7 cells irradiated with simple us at different powers. (e) ROS green fluorescence for H-HM@BSA irradiated with us at different powers. (f) ROS green fluorescence and (g) CCK-8 results of different groups. (h) Fluorescent images of live/dead cell and (i) CCK-8 results of the MCF-7 cells acquired after various treatments (white scale bar denotes 200 μm). The date are expressed as means ± SD (n = 3). (***p < 0.001, **p < 0.01, and *p < 0.05).