Core-satellite-structured magnetic nanozyme enables the ultrasensitive colorimetric detection of multiple drug residues on lateral flow immunoassay.

BACKGROUND

Excessive use of veterinary drugs causes severely environmental pollution and agricultural pollution, and poses great threat to human health. A simple method for the rapid, highly sensitive, and on-site monitoring of veterinary drug residues in complex samples remains lacking.

RESULTS

In this study, we propose a catalytically enhanced colorimetric lateral flow immunoassay (LFA) based on a novel core-satellite-structured magnetic nanozyme (Fe-Au@Pt) that can simultaneously and quantitatively detect three common veterinary drugs, namely, gentamicin (GM), streptomycin (STR), and clenbuterol (CLE), within a short testing time (<30 min). The Fe-Au@Pt nanozyme was simply prepared through the self-assembly of numerous Au@Pt nanoparticles on a large FeO core via electrostatic adhesion, which exhibited the advantages of high peroxidase-like activity, strong magnetic responsiveness, and multiple catalytic sites. Under the dual-signal amplification effect of magnetic enrichment and catalytic enhancement, the proposed nanozyme-LFA allowed the multiplex detection of STR, CLE, and GM with detection limits of 10.1, 6.3, and 1.1 pg/mL, respectively.

SIGNIFICANCE

The developed Fe-Au@Pt-LFA achieves direct, simultaneous, and accurate detection of three target drugs in food samples (honey, milk, and pork). The proposed assay shows great potential for application in the real-time monitoring of small-molecule pollutants in complex environment.