Gold nanoparticles-based lateral flow immunoassay with silver staining for simultaneous detection of fumonisin B1 and deoxynivalenol

A lateral flow immunoassay with silver staining for the simultaneous detection of fumonisin B₁ (FB₁) and deoxynivalenol (DON) in maize samples was reported. The assay was based on the competition between target mycotoxins and corresponding coating antigens immobilized on test lines for binding to limited gold nanoparticles (AuNPs)-labeled antibodies. The detection signal was further amplified by employment of silver staining on AuNPs. In the process, silver ions were catalyzed by AuNPs into metal silver that deposited on the surface of AuNPs, allowing not only the enlargement of particle dimensions of AuNPs but also a more distinguishable black coloration on the test zone. Under optimized conditions, the cut-off values of silver staining lateral flow immunoassay were 2.0 ng mL^?1 for FB₁ and 40 ng mL^?1 for DON in buffer, which was improved at least 2 times in comparison to those of AuNPs-based method. The assay was further applied to detect FB₁ and DON in naturally contaminated maize samples and a good agreement was found with the data obtained from HPLC-MS/MS.