Ultrasensitive determination of aflatoxin B1 by flow injection chemiluminescence immunoassay based on...

Nanozymes are promising alternatives to natural enzymes in biosensing applications. To address the critical need for sensitive detection of the food contaminant aflatoxin B1 (AFB1), this study developed a chemiluminescence immunosensor utilizing a novel Tb-MOF(Fe) nanozyme. The Tb³⁺-based metal-organic framework (MOF) was synthesized via a facile one-pot method employing 4,4'-oxybisbenzoic acid (OBBA) and catalytic hemin as ligands. Encapsulation of hemin within the MOF matrix markedly enhanced the stability and peroxidase-like activity of the material. Featuring an abundant porous structure and numerous active sites, the resulting Tb-MOF(Fe) substantially enhanced the chemiluminescence (CL) intensity of the luminol-H₂O₂ system. These properties enable the construction of multifunctional immunoprobes that integrate catalysis, luminescence enhancement and antibody immobilization. Implementing Tb-MOF(Fe) within a flow-injection chemiluminescence immunoassay (FI-CLIA) facilitated ultrasensitive detection of AFB1. The assay demonstrated a broad linear range (0.004-1000 ng mL^-1), ultralow limit of detection (LOD) (1.3 pg mL^-1, S/N = 3), and reliable spiked recovery rates (86.92-118.87%) in complex corn and wheat matrices, confirming its practical applicability in complex matrices. This study provides a highly sensitive strategy for AFB1 detection and advances the application of nanozymes in food safety.