Fig. 4

a Representative NIR-II fluorescence images at various time points after tail-vein administration of A1 NPs. b Tumor TBR of different time points after tail-vein injection of A1 NPs. c, d NIR-II images and fluorescence signal intensity of the tumor and main organs at 108 h after A1 NPs injection. e–g Tumor and adjacent vascular imaging at different time points of tumor-bearing mice. h Cross-sectional fluorescence intensity profiles of white arrows as indicated in g