Fig. 2From: Indocyanine Green Loaded Reduced Graphene Oxide for In Vivo Photoacoustic/Fluorescence Dual-Modality Tumor ImagingSynthesis and characterization of rNGO-PEG/ICG. a, b AFM images of rNGO-PEG and rNGO-PEG/ICG. c UV–vis absorption spectra of free ICG, rNGO-PEG, and rNGO-PEG/ICG solutions. d Fluorescence spectra of ICG and rNGO-PEG/ICG solutions with the same concentration of ICGBack to article page