Fig. 3

Gastric cancer imaging ex vivo and in vivo by CDH17 nanobody E8. a E8 nanobody (green) co-localization with CDH17-positve MKN45 cells (red) in zebrafish embryos. The appearance of zebrafish embryos (left) and co-localization of nanobody with cells (right). Dashed circles indicated the areas for quantification. b Quantification of co-localization (yellow) ratio to total red cells (n = 10, ****p < 0.0001, two-tailed student’s t test). Data are present as mean ± SEM. c and e Imaging of in vivo tumor-bearing mice with IR-800-labelled nanobodies in different time points (c, n = 3). Quantification analysis indicated that E8 nanobody in tumors produced significantly stronger signals as compared with control nanobody at each time point (e, n = 3, *p < 0.05, **p < 0.01, two-tailed student’s t-test). d and f Ex vivo imaging of major organs dissected from in vivo imaged mice in c (d, n = 3). Imaging quantification disclosed the strongest signals in E8-treated tumor tissues than all the control organs from both groups (f, n = 3, **p < 0.01, two-tailed student’s t-test). g Nanobody tissue distribution 12 hours after intravenous administration. Scale bars:50 μm. E8 nanobody could specifically accumulate into CDH17-positive tumor mass. Liver tissues showed some weak staining due to unspecific phagocytosis