Laccase-mimicking enzyme with fluorescent properties for dual-mode detection of epinephrine and degradation of phenolic pollutants.

Despite considerable interest has been shown in research on nanozymes in recent times, the creation of highly active bifunctional nanozymes remains a significant challenge. Inspired by the structural features of the active center of natural laccase, bifunctional copper-based nanozymes (Cu-MB) possessing both laccase-like activity and fluorescence properties using 2-methylimidazole (2-MI) and 2-aminoterephthalic acid (BDC-NH2) as ligands have been prepared. The Km of Cu-MB was 0.0898 mM, which was markedly lower than that of previously reported nanozymes and natural laccase. A dual-mode sensor for the detection of epinephrine (EP) was designed based on the high catalytic activity, excellent fluorescence properties, and stability of Cu-MB nanozymes. The limits of detection (LODs) of the colorimetric and fluorescence sensors for EP were 0.22 µg/mL and 0.11 µg/mL, respectively. The sensor system was verified to have good resistance to interferences and reliability by analyzing actual samples. Furthermore, the integration of a dual-reading hydrogel with a smartphone facilitates the portable, real-time, and rapid assessment of EP. More encouragingly, Cu-MB has excellent substrate versatility and can effectively degrade a diverse array of phenolic pollutants. The developed Cu-MB nanozymes provide a promising approach for the degradation and determination of phenolic compounds. Clinical trial number: not applicable.