Development of immunoassay based on three-dimensional MnO2@Pt nanozyme for the detection of fluoroquinolones residue in animal derived food.

Abstract

In this study, a highly sensitive and selective immunoassay based on three-dimensional MnO2@Pt nanozyme for the broad-spectrum detection of multiple fluoroquinolones (FQs) residue was designed. The assay utilises the in-situ reduction of platinum nanoparticles (PtNPs) onto three-dimensional MnO2 nanoflowers (MnO2 NFs), which act as a robust scaffold due to their large specific surface area and abundant spatial sites. This hierarchical nanostructure not only enhances the deposition efficiency of PtNPs but also substantially amplifies the colorimetric signal, enabling precise quantification of FQs. Using norfloxacin (NOR) as a model analyte, the assay exhibits a broad linear detection range (0.035-64.0 μg L-1) and achieves an exceptionally low limit of detection (LOD) of 0.016 μg L-1. The reliability of assay is confirmed by comparing NOR recovery rates in animal-derived food samples with those obtained via HPLC, demonstrating good consistency. Notably, this approach offers significant advantages over conventional ELISA including an LOD 13 times lower than that of the ELISA using HRP (LOD = 0.21 μg L-1). These results highlight the potential of PtNPs@MnO2 NFs-based immunoassay strategy platforms as rapid, cost-effective, and ultra-sensitive tools for monitoring FQs residues in food safety applications.

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