Self-sacrificing-induced defect enhances the oxidase-like activity of MnOOH for total antioxidant capacity evaluation

Nanozymes is a kind of nanomaterials with enzyme catalytic properties. Compared with natural enzymes, nanozymes emerge the advantages of both nanomaterials and natural enzymes, which is highly important in applications such as biosensing, clinical diagnosis, and food inspection. In this study, we prepared β-MnOOH hexagonal nanoflakes with a high oxygen vacancy ratio by utilizing SeO2 as a sacrificial agent. The defect-rich MnOOH hexagonal nanoflakes demonstrated excellent oxidase-like activity, catalyzing the oxidation substrate in the presence of O2, thereby rapidly triggering a color reaction. Consequently, a colorimetric sensing platform was constructed to assess the total antioxidant capacity in commercial beverages. The strategy of introducing defects in situ holds great significance for the synthesis of a series of high-performance metal oxide nanozymes, driving the development of faster and more efficient biosensing and analysis methods.