Determination of uric acid in serum by SERS system based on VO-MnCo2O4/Ag nanozyme

The level of uric acid is crucial to human health. Octahedral oxygen vacancy MnCo2O4/Ag (VO-MnCo2O4/Ag) nanozyme was successfully prepared by simple hydrothermal, calcination and self-reduction methods. VO-MnCo2O4/Ag nanozyme is rich in Mn2+/Mn3+ and CO2+/CO3+ redox electron pairs, large specific surface area and oxygen vacancies. VO-MnCo2O4/Ag nanozyme showed high uricase-like activity and peroxidase-like activity. At the same time, the SERS signal of the detected molecule could be significantly enhanced after the catalytic reaction of the VO-MnCo2O4/Ag nanozyme. The Km values of VO-MnCo2O4/Ag nanozyme for H2O2 and TMB were 0.04 mM and 0.027 mM respectively. Based on the uric acid oxidase-like and peroxidase-like activities of VO-MnCo2O4/Ag, we developed a label-free, sensitive, and reliable SERS uric acid detection system. The detection linear range of uric acid is 0.01 μM–1000 μM and the detection of limit is 7.8 × 10−9 M. The results show that the sensing system has good accuracy, sensitivity, selectivity, and stability. It can be applied to the determination of samples under different conditions. This study provides profound insights into the design of enzyme-like activity regulation and SERS properties regulation of nanozymes, provides guidance for the study of reaction kinetics and catalytic mechanism of nanozymes, and has broad application prospects in the field of nanozymes and SERS sensing analysis.