Lanthanide-doped luminescent lateral flow immunoassay for the ultrasensitive and quick detection of methyltestosterone in fish samples.

Hormone residues, especially in aquatic products, have become a serious threat to food safety. The development of sensitive, affordable, on-site, and quick detection methods for hormone residues still faces great challenges. Herein, taking methyltestosterone (MT) as a representative analyte, a competitive lateral flow immunoassay (LFIA) platform was constructed using ultrabright lanthanide-doped luminescent nanoparticles, YVO:Eu, as the label probe. The YVO:Eu NPs were obtained by a facile hydrothermal method using lanthanide ions and sodium orthovanadate as the precursors and polyacrylic acid as the surface modifier. Owing to the advantages of high fluorescence quantum yield, abundant surface functional groups, good dispersity and good water solubility, the harvested YVO:Eu NPs are a competitive and promising label probe in LFIA. The YVO:Eu LFIA test strips showed a detection limit, 0.1 ng mL, which was about 1 to 2 orders of magnitude lower than that of most reported methods. Furthermore, the proposed test strips were successfully applied for the quantitative, accurate, and quick screening of MT in fish samples. This work reports a competitive luminescent label probe for food safety and quality control.