SERS-Based Non-Enzymatic Detection of Uric Acid Using Au/CeO₂ Nanorods

Rapid and sensitive detection of uric acid (UA) has broad application prospects in biosensing and biomedical applications. Based on the surface-enhanced Raman scattering (SERS) system, Au/cerium oxide (CeO2) nanorods with excellent catalytic performance and high SERS activity were developed for highly sensitive detection of UA. Uniformly dispersed rod-like CeO2 was prepared by hydrothermal synthesis. Then, Au NPs were decorated on CeO2 by a simple in situ growth strategy. The concentrations of Ce3+ ions and oxygen vacancies were increased by increasing the number of Au NPs to obtain the optimal modification ratio. Moreover, Au NPs as active SERS substrates further significantly improve the detection sensitivity. Benefiting from the excellent performance, the Au/CeO2 nanorods were combined with 3,3′,5,5′-tetramethylbenzidine (TMB) and H2O2 to explore the valence change of Ce and the internal catalytic mechanism of reactive oxygen species generation in the reaction. Under optimized conditions, the SERS system for detection of UA was constructed for enzyme-free, with a wide range and low limit of detection of 3.29 × 10–10 M. Based on the strong peroxidase-like activity of Au/CeO2 nanorods under acidic conditions, it was successfully applied to the detection of UA in human urine samples. Therefore, this study provides proof that Au NPs enhance the peroxidase-like activity of Au/CeO2 nanorods for SERS detection of UA.