Synthesis of High-Entropy Hydrotalcite Nanozymes for Uric Acid Detection: A Comprehensive Experimental Design for Undergraduate Students

Uric acid (UA), a key product of purine metabolism, serves as an important biomarker for the diagnosis of various diseases. However, achieving UA detection with high sensitivity, a wide linear range, and a low limit of detection (LOD) remains a significant challenge. In this study, a novel colorimetric detection method based on high-entropy layered double hydroxide (HE-LDH) nanozymes was developed. The HE-LDHs, incorporating five metal elements (Cu, Fe, Zn, Ni, and Mn), were synthesized via a coprecipitation-hydrothermal process, supplemented with ultrasonic treatment (200 W, 40 kHz, 3 min) to optimize dispersibility and structural stability. The HE-LDHs exhibited excellent urate oxidase-like and peroxidase-like activities, enabling the sensitive and visual identification of UA based on the TMB chromogenic system (λmax = 652 nm). Experimental results showed that the maximum reaction rate (Vmax) of the enzymatic reaction reached 0.25 M min–1, with a linear detection range of 0–200 μM for UA and an LOD of 0.1 μM (S/N = 3). The spiked recovery rate ranged from 98% to 120% (relative standard deviation, RSD < 3%). Furthermore, the method demonstrated good applicability in the analysis of urine samples. This work not only provides a reliable and low-cost analytical strategy for UA detection but also introduces cutting-edge content integrating advanced materials and biosensing into undergraduate experimental teaching, offering comprehensive practical training.