Advancing colorimetric sensing for creatinine detection in urine: a practical approach for renal health diagnostics

This study presents a novel and affordable colorimetric sensing approach for creatinine detection in urine, designed to address key limitations of conventional methods such as susceptibility to interference and reliance on laboratory-based instrumentation, which may restrict their use in decentralized or resource-limited settings. Leveraging the unique properties of pH-sensitive dyes—Chlorophenol Red (CPR), M-Cresol Red (MCR), and Natural Red (NR)—this research achieves significant advancements in detection sensitivity and selectivity. Under optimized conditions, the dyes exhibit rapid response times (2 s) and distinct colorimetric changes upon exposure to creatinine. Notably, the method achieves a low limit of detection (LOD) of 0.51 mg/L with these dyes, highlighting its efficacy for detecting minute creatinine concentrations. Functionalized Whatman filter paper, integrated with these dyes, serves as the basis for a portable and cost-effective paper-based sensor, providing visual detection complemented by quantitative RGB analysis using image processing software. The system demonstrated excellent stability under varying pH, temperature, humidity, and storage conditions, ensuring reliability in diverse environments. Selectivity tests confirmed negligible interference from common urinary constituents, affirming its robustness in complex biological matrices. This novel platform advances renal health diagnostics by offering a practical, scalable, and non-invasive solution tailored to clinical settings and resource-limited regions.