A Promising NIR-II Fluorescent Sensor for Peptide-Mediated Long-term Monitoring of Kidney Dysfunction.

Kidney disease is usually "silent" at the early stage but can lead to severe kidney failure later on. The development of bioimaging probes with rapid distribution and long-term retention in the kidney is significant for precisely diagnosing of renal diseases. Here, a feasible strategy of peptide mediated delivering and long-term accumulating (>48 h) of second near-infrared window (NIR-II) fluorophores into kidney is demonstrated. It is shown that both the hepatic cleared organic molecules and fast renal cleared ultrasmall nanoparticles can be retained in the kidney after conjugated to the peptide with high polarity. Moreover, a ROS-responsive activatable bilateral NIR-II sensor was designed based on the kidney targeting peptide, which enables both in vivo long-term kidney monitoring and in vitro urine detection. The capability of peptide-based sensor to detect early kidney injury and report on kidney dysfunctional progression is particularly crucial for chemotherapy regimen optimization and timely renoprotective intervention during medications.