Fig. 3

a The fluorescence imaging of free ICG and ICG–BSA NC (0.5% ICG content) solution samples (2.8 µg/mL, counted by ICG content) under a 704 nm laser irradiation in a Maestro™ in vivo fluorescence imaging system. b The fluorescence spectra of free ICG and ICG–BSA NC solution samples (2.8 µg/mL, counted by ICG content) under a 635 nm laser irradiation in a Maestro™ in vivo fluorescence imaging system. 1—Free ICG solution, 2—ICG–BSA NC solution