Fig. 4

CFH/OM-L promotes deep penetration and intratumor distribution in vitro and vivo. A The fluorescence images and quantitative penetration of C6-NPs in 3D tumor spheres treated with CFH/OM-L (100 µM). Scale bar: 200 μm. The intra-3D tumor sphere fluorescence profile is plotted by ImageJ software. B Scheme of EMT reversion for tumor deep penetration in vivo. Step 2 represents the administration with various OM formulations and step 3 represents single injection with DiD-NPs. C α-SMA and Masson’s trichrome staining of tumor sections in various formulation groups. D The NIR images of tumor-bearing mice and ex vivo tumors, DiD-NPs is administrated after 24 h of treatments with the number (1), (2), (3), and (4), which represent the daily administration with saline, OM, OM-L, CFH/OM-L to mice, respectively, and E quantitative fluorescence of the ex vivo tumors. Data are represented as mean ± SD, n = 3, *P < 0.05. F Immunofluorescence and quantitative intratumoral distribution after treatment with the DiD-NPs at 24 h post the last administration of the OM formulations. The green represents blood vessels stained with CD31 antibody and the red represents the DiD-NPs. The scale bar is 500 μm. The representative region of tumor tissues is indicated by the yellow line (0–1.5 mm) and the corresponding fluorescence intensity profile is plotted through ImageJ software