Fig. 3

Dual-NIR-II color FGS of orthotopic CRC and mesenteric LNs. a NIR-II non-invasive in vivo imaging of orthotopic CRC mice post-injection of FE-2PEG via the tail vein at different time points. Scale bar: 1 cm. b Normalized FL intensity of the abdominal ROIs at different time points in (a) (n = 3, data are shown as mean ± SD). c White light and NIR-II imaging of exposed orthotopic CRC. The tumor size was 5.8 × 6.3 mm. The TNR was 3.40. Scale bar: 1 cm (top); Scale bar: 5 mm (down). d NIR-II FGS of the orthotopic tumors and reconstruction of the digestive tract. e H&E staining of the orthotopic tumor. The dotted line showed the tumor (T) and normal tissues (NT) boundary. Scale bar: 100 μm (up); Scale bar: 50 μm (down). f Dual-NIR-II color imaging of the orthotopic tumor and angiogenesis with FE-2PEG (1100 ~ 1300 nm) and QDs (> 1500 nm). Scale bar: 5 mm. g Profiles of the dotted line in (f). h Dual-NIR-II color imaging of the mesenteric lymph node and mesenteric blood vessels with FE-2PEG (1100 ~ 1300 nm) and QDs (> 1500 nm). Under the dual-NIR-II color navigation, the mesenteric lymph node was surgically excised, and the mesenteric blood vessels were protected. Scale bar: 5 mm