Bimetallic CuTb₂O₂ nanozyme-enabled enzyme-luminophore-nanozyme electrochemiluminescence sensor for sensitive...

In this study, we utilized bimetallic CuTb₂O₂ nanozyme to immobilize luminol and xanthine oxidase (XOD) to construct an enzyme-luminophore-nanoenzyme electrochemiluminescence sensor. The large specific surface area and porous structure of CuTb₂O₂ significantly enhances the loading capacity and interfacial stability of luminol and XOD, resulting in stable ECL signals from the sensor. XOD selectively catalyzes the oxidation of xanthine to generate H₂O₂, while the CuTb₂O₂ nanozyme rapidly catalyzes the in situ conversion of H₂O₂ into superoxide anion radicals (O₂•^-) and hydroxyl radicals (•OH), which serve as highly efficient co-reactants for luminol, thereby significantly amplifying the ECL signal. Under optimized conditions, the sensor exhibits a linear response range for xanthine from 1 × 10^-11 to 1 × 10^-6 M, with a detection limit of 6.39 × 10^-12 M (3σ/m). Additionally, it demonstrates excellent selectivity, reproducibility, and adaptability to complex biological matrices, making it suitable for the sensitive detection of xanthine in fish samples.