Fig. 2

a The SEM characterization of the prepared ICG–BSA NC. b The TEM characterization of the prepared ICG–BSA NC. c The DLS characterization of the prepared ICG–BSA NC (red) and single BSA (blue). d The UV–Vis–NIR absorption spectra and fluorescence emission spectra of free ICG molecule (black line) and ICG–BSA NC (red line) in 1× PBS (pH 7.4)