Ultrasensitive chemiluminescent probe activated by NAG for real-time monitoring of AKI.

Acute kidney injury (AKI) not only increases the likelihood of developing chronic kidney disease (CKD) but also leads to considerable morbidity and mortality, highlighting the urgent need for early diagnostic tools. Current techniques that depend on serum creatinine (sCr) and blood urea nitrogen (BUN) are not sensitive enough to detect early tubular damage. To overcome this limitation, we created NAG-CL, a chemiluminescent probe activated by N-acetyl-β-D-glucosaminidase (NAG), which serves as a biomarker that rises in the early stages of AKI. The NAG-CL operates through NAG-mediated enzymatic cleavage of the protective moiety, yielding a fluorescent product while concomitantly triggering a robust chemiluminescent emission. It offers superior advantages, including rapid activation (in less than 20 min), an ultra-low detection limit (0.004 U/L) and high selectivity. In vitro studies have confirmed its specificity and sensitivity, surpassing traditional fluorescent probes by 16.4 times in terms of lower limit of detection (LOD). Non-invasive urine tests in mice with cisplatin-induced AKI showed early detection of NAG, which correlated with the progression of renal injury. Significantly, NAG-CL demonstrates a notable ability to distinguish between patients and healthy individuals' urine samples, indicating its potential utility in the diagnosis of kidney injury. This study established NAG-CL as a chemiluminescent probe for realtime, non-invasive monitoring of acute kidney injury (AKI), demonstrating superior performance compared to existing methods, and holds promise as a fast and effective non-invasive diagnostic tool for AKI in clinical settings.