A self-assembled silver nanowire-based SERS sensor with creatinine internal standard for the detection of uric acid in urine

Rapid and reliable detection of uric acid is crucial for a prompt diagnosis of metabolic disorders. However, this remains challenging due to the intricacy of biological matrices and the limitations of current analytical methods. In this study, a surface-enhanced Raman scattering (SERS) sensor based on silver nanowire arrays functionalized with cetyltrimethylammonium chloride (Ag NWs@CTAC) was developed for the quantitative detection of uric acid in human urine. To ensure accuracy, creatinine, a metabolite excreted at a steady rate, was introduced as an internal standard to correct for signal fluctuations. The positively charged CTAC layer enhanced selectivity by electrostatically adsorbing negatively charged uric acid. Additionally, the uniformly arranged Ag NWs@CTAC array provided high density and repeatable SERS hotspots, ensuring both uniformity and signal enhancement. The sensor achieved a detection limit as low as 1.27 mg L^-1 for uric acid, along with accurate recovery rates in artificial urine samples. These features make the Ag NWs@CTAC SERS sensor a promising candidate for quick, accurate, and reliable uric acid detection in clinical and point-of-care applications.