To achieve the whole process monitoring and evaluation of renal transplantation surgery through fluorescence, long circulation time of contrast agents in the bloodstream is necessary. Intravenous injection of 60 µg (0.3 mg/mL in PBS, 200 µL per mouse) DIPT-ICF NPs into Balb/c nude mice, strong fluorescent signal of DIPT-ICF NPs could be observed from the serum even after 24 hours' circulation in blood (Fig. ). As a contrast, when 200 µl of ICG aqueous solution were injected into Balb/c nude mice, a relatively weak fluorescent signal could be observed from serum which started to decay after 30 min (Fig. ). Comparison between the mean fluorescence signal intensity of ICG and DIPT-ICF NPs contained in the serum indicated that both the fluorescent intensity and circulation time of DIPT-ICF NPs is superior than that of ICG (Fig. ). The long-circulating capability of DIPT-ICF NPs in angiography was also confirmed. As shown in Fig. and, after 720 min post-injection of DIPT-ICF NPs, the abdominal vascular textures remained visible.