Fe/Co-MOF-based cascade biocatalytic platform for ultrasensitive detection of α-amylase.

A novel biosensor for detection of α-amylase, a key functional enzyme in Daqu fermentation, has been developed addressing the challenges of interference and inefficiency associated with conventional methods. In the multi-enzymes cascade system (Glu-GOx@MOF), the enzymes were immobilized on metal–organic frameworks (MOF) with excellent peroxidase-like activity through a covalent bonding method, enabling efficient and sensitive detection of α-amylase activity. Combining theoretical calculations with experiments, we have demonstrated that the Fe/Co-MOF possesses remarkable peroxidase-mimicking properties. Therefore, Fe/Co-MOF not only serves as a reliable carrier for multiple enzymes but also functions as a high-performance nanozyme in cascade reactions. Compared with natural enzymes, this biocatalytic platform exhibits excellent cascade catalytic activity and stability in various harsh environments. On this basis, a cascade biocatalytic platform for α-amylase detection was developed, demonstrating a wide linear range from 25 to 18,000 U L⁻1 and a low detection limit of 10.8 U L⁻1. This work not only provides a robust tool for α-amylase monitoring in food quality control but also establishes a novel cascade amplification strategy utilizing enzyme-MOF hybrid systems for biosensing applications.