Portable Ratiometric Fluorescence Sensor for Immediate Creatinine Detection in Early Medical Screening

Accurate and rapid detection of urinary creatinine (CR) is critical for early kidney disease screening and efficient healthcare resource management. In this study, a novel colorimetric‐fluorescent sensor is developed by integrating nitrogen‐doped carbon dots (N‐CDs) and copper nanoclusters (CuNCs) with gold nanoparticles (AuNPs), leveraging fluorescence resonance energy transfer (FRET) to enhance sensitivity and selectivity. The sensor functions within a detection range of 1–50 m m , with peak responsiveness at 17 m m , utilizing paper‐based substrates for a low‐cost and portable application. Additionally, the sensor demonstrates excellent stability, high selectivity, and strong resistance to interference from other substances, ensuring accurate detection of CR in complex samples. These findings indicate that the dual‐probe system significantly improves detection accuracy and operational simplicity compared to traditional CR measurement techniques. This innovative sensor offers a promising platform for rapid, on‐site CR analysis, facilitating early diagnosis and effective monitoring of kidney diseases in diverse settings.