Electrochemical magnetic beads-based immunosensing platform for the determination of α-lactalbumin in milk

• Published in: Food chemistry 2016-12, Vol.213, p.595-601
• Main Authors: Ruiz-Valdepeñas Montiel, Víctor, Campuzano, Susana, Torrente-Rodríguez, Rebeca M., Reviejo, A. Julio, Pingarrón, José M.
• Format: Article
• Language: English
• Subjects: Amperometric immunosensors; Animals; Biosensing Techniques - methods; Cattle; Female; Humans; Immunomagnetic Separation - methods; Infant formulas; Lactalbumin - chemistry; Magnetic beads; Milk; Milk - chemistry; α-Lactalbumin
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2016.07.004

[Display omitted] •First amperometric MBs-based immunosensor for α-LA with excellent sensitivity (LOD 11.0pgmL−1) and selectivity.•Determination of α-LA in different milk samples and infant formulas.•Good correlation against results provided by a commercial ELISA spectrophotometric kit.•Powerful analytical tool for food safety and consumer protection. Alpha-lactalbumin (α-LA) is one of the whey proteins in cows’ milk that has been identified as allergenic. In this work, we present, for the first time, a very sensitive magnetic beads (MBs)-based immunosensor for the determination of α-LA. A sandwich configuration involving selective capture and horseradish peroxidase-labeled detector antibodies was implemented on carboxylic acid-modified magnetic beads, captured magnetically under the surface of a disposable screen-printed carbon electrode for amperometric detection using the hydroquinone (HQ)/H2O2 system. The α-LA immunosensor exhibited a wide linear range (37.0–5000pg/ml), a low limit of detection (LOD, 11.0pg/ml) and noteworthy selectivity against other non-target proteins. The MBs-based immunosensing platform was applied successfully for the determination of α-LA in several varieties of milk (raw and UHT cows’ milk as well as human milk) and infant formulations. The results were corroborated with those obtained using a commercial ELISA method, thereby substantiating the analytical merits of this unique method.