Amino-functionalized CdSe/ZnS quantum dot-based lateral flow immunoassay for sensitive detection of aflatoxin B1

摘要

In this study, highly fluorescent amino-functionalized CdSe/ZnS core/shell quantum dots (CdSe/ZnS QDs) coated with amphiphilic N-alkylated poly(ethyleneimine) have been synthesized and applied as fluorescent probes in lateral flow immunoassay (LFIA) strips for on-site determination of aflatoxin B1 (AFB1). The amino-functionalized QDs were used to combine with anti-AFB1 via thiol-maleimide conjugation and they effectively enhanced the detection sensitivity. The test strip had high sensitivity for AFB1 from 0.001 ng mL?1 to 10 ng mL?1 with a low limit of detection (LOD) of 0.005 ng mL?1, which was much lower than the allowable concentration by the European Commission (EC) (2.0 μg kg?1) and FDA (20 μg kg?1). The IC50 value was calculated to be 0.025 ng mL?1. The reproducibility and recovery tests showed that the quantitative results were accurate, and it could be used for rapid on-site detection of AFB1 in cereal products.