High-entropy alloy nanozymes as a robust signal generator for point-of-care visual detection of metabolites

Cholesterol and glucose are important indicators for food quality control and disease diagnosis. Herein, a visual biosensing strategy is developed for cholesterol and glucose detection using carbon nanotube–supported ruthenium-doped high-entropy PtFeNiCuW nanoparticles (Ru-PtFeNiCuW/CNTs). The nanozyme exhibits pronounced peroxidase-like activity and can be coupled with hydrogen peroxide-generating cholesterol oxidase or glucose oxidase to catalyze the oxidation of colorless o -phenylenediamine into yellow 2,3-diaminophenazine, enabling both fluorescence-based and smartphone-assisted colorimetric analysis. In the fluorescence mode, cholesterol and glucose display good linear responses over a concentration range of 0.5 to 400 μg/mL, with a detection limit of 94.73 and 88.70 ng/mL, respectively. The proposed platform is successfully applied to the determination of cholesterol and glucose in actual food samples and clinical serum samples, with results showing good agreement with those by conventional analytical and clinical reference methods. This work demonstrates the unique potential of high-entropy alloy nanozymes for constructing efficient and practical biosensing platforms for food analysis and healthcare diagnostics.