Multifunctional nanoenzyme lateral flow immunoassay strip for rapid and ultrasensitive detection of carbofuran in vegetables.

A lateral flow immunoassay strip (LFIAS) is one of the most frequently rapid test technologies for carbofuran (CAR). Nevertheless, the LFIAS has a poor quantitative capability and low sensitivity. And, it also requires often complex sample handling steps, making testing time longer. In this study, FeO nanoparticles were successively modified with MIL-100(Fe)-based metal-organic framework (MOF) and chloroplatinic acid hexahydrate to obtain a core-shell complex of FeO-MOF-Pt. The complex had a peroxidase-mimicking activity catalytic function that enabled signal amplification and sensitivity enhancement. Upon coupling with carbofuran monoclonal antibody (CAR-mAb), the magnetic separation properties of the probe enabled target-specific enrichment. The LFIAS based on FeO-MOF-Pt nanocomposites could detect CAR in the range of 0.25-50 ng mL with a limit of detection (LOD) of 0.15 ng mL, enabling colorimetric and catalytic analysis. In addition, the method showed high specificity and stability for detecting CAR in various vegetables, and recovery rates of the spiked samples were 91.40%-102.40%. In conclusion, this study provided one-stop detection of "target enrichment-visual inspection". While lowering the LOD, it reduced the detection time and improved the detection efficiency. The multifunctional FeO-MOF-Pt nanocomposite provides an idea for the construction of novel multifunctional probes to improve the detection performance of conventional LFIAS.