A multi-enzyme cascade catalytic system constructed on MIL-88B(Fe)-NH₂ as a three-in-one fluorescent nanozyme for...

A multi‑enzyme cascade sensing platform for α‑amylase detection is reported constructed by integrating glucose oxidase (GOx), glucoamylase (Glu), and a peroxidase‑mimicking metal-organic framework (NH₂‑MIL‑88B) into a cascade catalytic system. In this design, α‑amylase hydrolyzes starch to generate maltose, which is catalyzed sequentially by Glu and GOx to produce H₂O₂, followed by MOF‑mediated chromogenic oxidation to yield a measurable UV‑Vis signal. The generated ox-TMB can quench the fluorescence of NH₂-MIL-88B and cause a photothermal effect. Consequently, the platform achieved colorimetric/fluorescence/photothermal-based multimodal detection of α-amylase. The cascade strategy afforded significant signal amplification, enabling sensitive and selective detection. The system exhibited excellent selectivity against common interferents, including metal ions, small molecules, and proteins. Practical applicability was validated by assaying α‑amylase in Daqu. Remarkably, the assay is operationally simple. This work provides a promising solution for α‑amylase monitoring in complex samples, with broad prospects in food safety control.