Kidney-Targeted Near-Infrared Fluorescence Probe Reveals That SO₂ Is a Biomarker for Cisplatin-Induced Acute Kidney Injury

Withthe widespread use of drugs, drug-induced acute kidney injury(AKI) has become an increasingly serious health concern worldwide.Currently, early diagnosis of drug-induced AKI remains challengingbecause of the lack of effective biomarkers and noninvasive imagingtools. SO2 plays important physiological roles in livingsystems and is an important antioxidant for maintaining redox homeostasis.However, the relationship between SO2 (in water as SO3 (2-)/HSO3 (-)) anddrug-induced AKI remains largely unknown. Herein, we report the highlysensitive near-infrared fluorescence probe DSMN, whichfor the first time reveals the relationship between SO2 and drug-induced AKI. The probe responds to SO3 (2-)/HSO3 (-) selectively and rapidly (withinseconds) and shows a significant turn-on fluorescence at 710 nm witha large Stokes shift (125 nm). With these properties, the probe wassuccessfully applied to detect SO2 in living cells andmice. Importantly, the probe can selectively target the kidneys, allowingfor the detection of changes in the SO2 concentration inthe kidneys. Based on this, DSMN was successfully usedto detect cisplatin-induced AKI and revealed an increase in the SO2 levels. The results indicate that SO2 is a newbiomarker for AKI and that DSMN is a powerful tool forstudying and diagnosing drug-induced AKI.