A Renal-Clearable Ultrasmall NIR-II Nanoprobe for Etiology-Independent Early Diagnosis of Kidney Injury
Early detection of kidney injury remains difficult because routine clinical indicators often lag behind tissue damage. Here we report uNP-CH1055, an ultrasmall renal-clearable NIR-II fluorescent nanoprobe for non-invasive imaging of kidney injury in vivo. uNP-CH1055 formed stable nanoparticles with a hydrodynamic diameter of 3.3 nm, showed good photostability, enabled low-background imaging under a 1200 nm long-pass filter, and underwent rapid renal clearance after intravenous administration. It also exhibited favorable biocompatibility in both cellular and animal studies. In three mechanistically distinct models of renal injury, cisplatin-induced acute kidney injury, ischemia–reperfusion injury and unilateral ureteral obstruction, renal fluorescence increased with injury severity and closely paralleled biochemical and histological indicators, including blood urea nitrogen, serum creatinine, KIM-1 and TUNEL-based readouts. These results identify uNP-CH1055 as a renal-clearable NIR-II probe for early and quantitative assessment of kidney injury across different pathological settings.