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.

Automated summary

In this work, a three-in-one artificial enzyme with enhanced peroxidase-like activity and outstanding stability is constructed by restricting Au-loaded CeO2 nanorods inside Cu-based metal-organic frameworks. The artificial enzyme shows significantly improved catalytic decomposition of H2O2 and strong affinities to substrates, with lower Michaelis constants than horseradish peroxidase. It also exhibits desirable stabilities in pH, temperature, organic solvents, and long-term storage. A universal colorimetric/fluorometric dual-mode sensing platform is built based on the artificial enzyme for detection of biomarkers in biological fluids. This work opens up new possibilities for designing efficient and stable biomimetic catalysts.