Fig. 4

The penetration and antitumor efficacy in 3D tumor models and in vivo biodistribution. (A) 3D tumor spheroid model. Blue fluorescence: DAPI, green fluorescence: DiO, red fluorescence: DiD, Scale bar: 100 μm. (B) The images of in vitro tumor spheroids penetration of each group were acquired by CLSM at 10× objective magnification using Z-stack imaging from the bottom of the spheroids at 20 μm intervals. DiO-stained C4-2B EnzR cells and DiD-stained MG-63 cells were seeded in the 96-well plates at the ratio of 1:1. (DiR: 20 µg·mL^− 1, miFAM: 0.5 µg·mL^− 1). Scale bar: 100 μm. (C) The tumor spheroids with a diameter of about 400 μm were co-incubated with different formulations for 48 h (Enz: 50 µg·mL^− 1, miR26a: 1 µg·mL^− 1) and images were acquired by CLSM. Scale bar: 100 μm. Representative small animal living images of the biodistribution of each group in (D) subcutaneous CRPC and (E) BmCRPC mouse models at 0–24 h. Free DiR and DiR-loaded Bm/PT nanoparticles were injected at a concentration of 10 mg·kg^− 1. (F) Distribution in major organs of each group in subcutaneous CRPC and (G) BmCRPC mouse models. Quantified distribution in major organs of each group in (H) subcutaneous CRPC and I. BmCRPC mouse models. n = 3, mean ± SD, *p < 0.05, **p < 0.01, one-way ANOVA