Colorimetric detection of uric acid based on an anti-etching mechanism using gold nanorods and I3-

Uric acid (UA) serves as a crucial biomarker, its abnormal levels can lead to various diseases, including gout and Parkinson's disease. Consequently, the rapid detection of UA in biofluids is essential for clinical diagnosis, monitoring and disease prevention. This study developed a convenient colorimetric assay for the detection of UA using gold nanorods (Au NRs) based on the reductive property of UA and using I 3 - as an oxidative etchant. At room temperature, I 3 - oxidatively etched Au NRs, prompting a blue shift in the longitudinal localized surface plasmon resonance (LSPR) absorption peak of Au NRs, altering solution color from blue to pink. As a reducing agent, UA is capable of inhibiting the etching process of Au NRs induced using I 3 - through redox reaction, thereby preserving the original color of the solution. This detection strategy displays good selectivity and anti-interference capabilities, achieving an unaided eye detection limit of 5 μM and a UV–vis absorption spectroscopy detection limit of 1.51 μM. Furthermore, it exhibits satisfactory performance when it was applied to practical samples, offering an innovative sensing approach for UA detection with significant potential for application in clinical analysis.