Fig. 4

The accumulation and biodistribution of NDs. A Cellular uptake of DiO-labeled NDs under different pH values at 1, 4 h. NDs labeled with DiO appeared green dots, and cell nuclei counterstained by Hoechst were blue. Scale bar: 50 μm. B FCM of Hepa1-6 cells treated with DiO-labeled NDs under different pH values at 1, 4 h. C Cell internalization rate of NDs obtained from B. D Representative in vivo images of tumor-bearing mice after intravenous administration of NDs. E Representative ex vivo image of main organs at 24 h. F Semiquantitative data of fluorescence in major organs from E. G The accumulation of NDs at tumors at 24 h. NDs labeled with DiI showed red dots, and cell nuclei stained by DAPI were blue. Scale bar: 100 μm. Data are presented as mean ± SD (n = 3, *p < 0.05, **p < 0.01)