Au/CeO₂ NR Restricted Inside Cu-MOFs: A Three-in-One Artificial Enzyme with Synergistically Enhanced Peroxidase-Like Activity for Dual-Mode Sensing of Multiple Biomarkers

Nanomaterialswith inherent enzyme-mimetic propertieshave beenextensively studied in biosensing field, but it is still challengingto overcome their natively weak enzyme-mimetic activity and furtherpromote their stabilities. In this work, a three-in-one artificialenzyme with synergistically enhanced peroxidase-like activity andoutstanding stability is constructed by restricting Au-loaded CeO2 nanorods (NR) (1% Au:CeO2 mass ratio) inside Cu-basedmetal-organic frameworks (Cu-(PABA)), termed Au-1/CeO2 NR@Cu-(PABA). It has been demonstrated that the artificialenzyme possesses significantly improved performance in catalytic decompositionof H2O2, with similar to 2.41 and similar to 1.49times higher activity than its individual constituents (Au-1/CeO2 NR and Cu-(PABA)), benefiting from the synergisticeffect and the unique restricted structure; owns strong affinitiesto substrates, with separately similar to 8.21- and similar to 3.13-foldlower Michaelis constants toward H2O2 and o-phenylenediamine, respectively, than horseradish peroxidase;and exhibits desirable pH (4-12), thermal (30-80 degrees C),organic solvent (N,N-dimethylformamide,acetone, methanol, etc.), and long-term storage (30 days) stabilities,advantaging practical applications. Taking aforementioned superiorproperties of Au-1/CeO2 NR@Cu-(PABA), a universalcolorimetric/fluorometric dual-mode sensing platform is built andutilized for detection of biomarkers (e.g., glucose, galactose, andcholesterol) in biological fluids with satisfactory recoveries (90.2-108%).This work offers new horizons in designing high-efficiency, stable,and credible biomimetic catalysts to accelerate future advanced engineeringof nanozymes. Restricting Au-1/CeO2 nanorods insideCu-(PABA) shows significantly enhanced peroxidase-like activity andsuperior stability, advantaging effective and sustainable utilizationof resources.