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Rapid immunofluorescence assay for staphylococcal enterotoxin A using magnetic nanoparticles
Author(s) -
Becheva Zlatina,
Ivanov Yavor,
Gabrovska Katya,
Godjevargova Tzonka
Publication year - 2019
Publication title -
international journal of food science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.831
H-Index - 96
eISSN - 1365-2621
pISSN - 0950-5423
DOI - 10.1111/ijfs.14018
Subject(s) - immunoassay , conjugate , enterotoxin , chromatography , chemistry , detection limit , monoclonal antibody , fluorescence , staphylococcus aureus , antibody , bacteria , biochemistry , biology , escherichia coli , immunology , mathematical analysis , physics , mathematics , quantum mechanics , gene , genetics
Summary A competitive immunoassay for staphylococcal enterotoxin A ( SEA ) detection in milk was developed, using immobilised antibody onto magnetic nanoparticles ( MNP s). MNP s were prepared and then modified to introduce amino groups on them. The morphology and size of the obtained both unmodified and modified MNP s were characterized using TEM analyses. Monoclonal anti‐ SEA antibody was immobilised onto the modified MNP s ( MNP ‐Ab). Staphylococcal enterotoxin A was conjugated with fluorescent dye ATTO 620 NHS . The characteristics of fluorescence conjugate were examined. The amount of MNP ‐Ab and concentration of the fluorescent conjugate used for competitive immunoassay were optimized: 0.25 mg and 53 μg mL −1 , respectively. The detection limit of developed immunoassay was determined – 0.23 ng mL −1 SEA in spiked milk samples. The immunoassay takes only 30 min, the magnetic separation is fast (<10 s) and the volume of the sample for analysis is very small (200 μL).