SERS-Based Non-Enzymatic\nDetection of Uric Acid Using\nAu/CeO<sub>2</sub> Nanorods

Rapid and sensitive detection of uric acid (UA) has broad\napplication\nprospects in biosensing and biomedical applications. Based on the\nsurface-enhanced Raman scattering (SERS) system, Au/cerium oxide (CeO<sub>2</sub>) nanorods with excellent catalytic performance and high SERS\nactivity were developed for highly sensitive detection of UA. Uniformly\ndispersed rod-like CeO<sub>2</sub> was prepared by hydrothermal synthesis.\nThen, Au NPs were decorated on CeO<sub>2</sub> by a simple in situ\ngrowth strategy. The concentrations of Ce<sup>3+</sup> ions and oxygen\nvacancies were increased by increasing the number of Au NPs to obtain\nthe optimal modification ratio. Moreover, Au NPs as active SERS substrates\nfurther significantly improve the detection sensitivity. Benefiting\nfrom the excellent performance, the Au/CeO<sub>2</sub> nanorods were\ncombined with 3,3′,5,5′-tetramethylbenzidine (TMB) and\nH<sub>2</sub>O<sub>2</sub> to explore the valence change of Ce and\nthe internal catalytic mechanism of reactive oxygen species generation\nin the reaction. Under optimized conditions, the SERS system for detection\nof UA was constructed for enzyme-free, with a wide range and low limit\nof detection of 3.29 × 10<sup>–10</sup> M. Based on the\nstrong peroxidase-like activity of Au/CeO<sub>2</sub> nanorods under\nacidic conditions, it was successfully applied to the detection of\nUA in human urine samples. Therefore, this study provides proof that\nAu NPs enhance the peroxidase-like activity of Au/CeO<sub>2</sub> nanorods\nfor SERS detection of UA.