Self-powered photoelectrochemical cholesterol sensor based on ZnO/C and Fe-doped CuBi2O4 nanocomposites

The quantitative determination of cholesterol in foods, drugs, and biological fluids holds significant importance due to its potential health risks. Herein, a self-powered photoelectrochemical (PEC) sensor was developed for cholesterol detection. The photoelectrochemical system was constructed by modifying fluorine-doped tin oxide (FTO) electrodes with ZnO/C (serving as the photoanode) and iron-modified CuBi 2 O 4 (denoted as CBFO, functioning as the photocathode) through a controlled deposition process. To enhance detection selectivity, molecularly imprinted polymers (MIPs) were electrodeposited on the photocathode surface. The optimized sensor exhibited a linear detection range of 1–1000 nmol L −1 and a detection limit of 0.26 nmol L −1 (S/N = 3). Practical application of the sensor for cholesterol detection in milk samples demonstrated satisfactory recovery rates (98.6 %–107 %) with relative standard deviations (RSD) ranging from 2.38 % to 4.25 %. These results underscore the potential of this self-powered PEC sensor as a robust platform for rapid and accurate cholesterol determination in food products, pharmaceuticals, and environmental samples.