MOF-derived yolk-shell CoN/Co-NC@SiO2 nanozyme with oxidase mimetic activities for colorimetric detection of glutathione

The development of nanozymes has garnered significant attention in biosensing applications owing to their exceptional catalytic properties and structural tunability. Herein, we present a yolk-shell nanozyme derived from metal-organic frameworks (MOFs) featuring CoN/Co-NC@SiO2 architecture, exhibiting remarkable oxidase mimetic activities for colorimetric glutathione (GSH) detection. The synthesis involves a facile pyrolysis process of cobalt-based MOFs encapsulated within a silica shell, resulting in a unique yolk-shell nanostructure with CoN/Co-NC active sites. Yolk-shell CoN/Co-NC@SiO2 has been studied in detail as an oxidase and catalase-like nanozyme. In consideration of structural and composition modulation, including hydrophilic SiO2 shell, the unique cavity, a high specific surface area and dispersed active sites, the CoN/Co-NC@SiO2 was proposed for colorimetric detection of glutathione with its oxidase-like activities. Based on the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) by CoN/Co-NC@SiO2, a wide linear detection range of 0.5–60 μM as well as a lower detection limit of 0.054 μM were obtained. Our research shows that optimizing structure and composition plays an important role in the construction of multiple-enzyme activity and offers bright potential applications of MOF-derived yolk-shell nanozymes in biosensing and medical diagnostics.