Fig. 5.

In vivo biodistribution and molecular imaging of IR820-SS-CPT NPs and free IR820. A In vivo NIR fluorescence images of 4T1 tumor-bearing nude mice by intravenous administration of IR820-SS-CPT NPs or free IR820 for 3, 6, 12, and 24 h. B Ex vivo fluorescence images of tumors and major organs at 24 h post-injection of IR820-SS-CPT NPs or free IR820. C PA images of the mice injected with IR820-SS-CPT NPs or free IR820 for 3, 6, 12, and 24 h. D Fluorescence intensity of tumors and major organs. E Photoacoustic signals in the tumors of the mice at different time points