Biodistribution on Day 30 after 4T1 cells inoculation and metastasis targeting capacity of different preparations. (A) Fluorescent images of tumors and major organs at 1, 8, 24 h after the administration of DOX, DD/DOX or FD/DOX. (B) Semiquantitative analysis of mean fluorescence intensity of tissues at 24 h after the administration. Data are presented as mean ± SD (n = 3), ∗∗P < 0.01, ∗∗∗P < 0.001. (C) The amount of DOX in tumors and major organs quantified by LC‒MS at 24 h after the administration. Data are presented as mean ± SD (n = 3), ∗P < 0.05, ∗∗P < 0.01, ∗∗∗P < 0.001. (D) Fluorescent images of frozen sections of tumor, lung metastasis and liver metastasis at 24 h after administration. Green: DOX; red: CD41 for staining platelets; blue: DAPI for staining cell nucleus. Scale bar = 100 μm. (E) Fluorescent images of frozen sections of tumor, lung metastasis and liver metastasis at 24 h after administration. Green: DOX; pink: CD31 for staining neovasculature; blue: DAPI for staining cell nucleus. Scale bar = 100 μm.