The fluorescence intensity of mice injected with PPC15 or PPC20 NPs displayed similar evolution within 12 hours. (Figure ). After 12 hours of administration, the ex vivo imaging results showed that the dependence of the mean fluorescence intensity at different band-pass wavelengths at tumors and livers was consistent with the fluorescence spectra of both NPs in water, suggesting the presence of J-aggregation in both PPC15 and PPC20 NPs under the physiological condition of mice in vivo (Figure & S9m, Figure ).