In vivo tumor targeting ability of peptides. (A) In vivo fluorescent imaging of mice bearing two U87MG tumors at bilateral symmetry axilla treated with free ICG, RWr-ICG, c(RGDyK)-ICG and RWrNM-ICG. *P < 0.05 (B) In vivo fluorescent imaging of mice bearing two HepG2 tumors at bilateral symmetry axilla treated with free ICG, RWr-ICG, c(RGDyK)-ICG and RWrNM-ICG. (C) In vivo fluorescent imaging of mice bearing U87MG and HepG2 tumors respectively at bilateral symmetry axilla treated with free ICG, RWr-ICG, c(RGDyK)-ICG and RWrNM-ICG. *P < 0.05 (Tumor/normal tissue (T/N) ratios at different time points after intravenous injection of different peptides conjugated with ICG, and fluorescence imaging of the tumors harvested from the mice (inset)).