Breaking the pH limitation of peroxidase-like CoFe2O4 nanozyme via vitriolization for one-step glucose detection at physiological pH

In recent years, a growing number of nanosized materials that can mimic the catalytic characteristics of some natural enzymes have experienced a period of rapid development. Among these nanomaterials defined as 'nanozymes', peroxidase-mimicking materials draw intensive interest because of their potential applications in various fields, including biosensing, medicine, and environmental engineering. Nonetheless, most of currently explored peroxidase nanozymes exhibit favorable activity only in acidic environments, which greatly restricts their use especially in biochemical analysis. Developing peroxidase mimics with good catalytic performance in a broad pH range is highly desired and still challenging. Herein, we report a vitriolization strategy to broaden the catalytic pH scope of peroxidase-like CoFe2O4. The vitriolization process endows the nanomaterial with sustainable acidity on its surface. As a result, the obtained peroxidase nanozyme (SO42/CoFe2O4) exhibits good catalytic activity in neutral or even weak alkaline solutions. This provides us a one-step assay for colorimetric glucose detection in one pot at physiological pH via combining the proposed peroxidase mimic with glucose oxidase, which shows advantages of easier operation and faster detection while offering comparable analytical performance.