Electrochemical magneto immunosensing of antibiotic residues in milk

A novel electrochemical immunosensing strategy for the detection of sulfonamide antibiotics in milk based on magnetic beads is presented. Among the different strategies for immobilizing the class-specific anti-sulfonamide antibody to the magnetic beads – such as those based on the use of Protein A o...

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Bibliographic Details
Published in:Biosensors & bioelectronics 2007-04, Vol.22 (9), p.2184-2191
Main Authors: Zacco, E., Adrian, J., Galve, R., Marco, M.-P., Alegret, S., Pividori, M.I.
Format: Article
Language:English
Subjects:
Animals
Anti-Bacterial Agents - analysis
Anti-Bacterial Agents - immunology
Biological and medical sciences
Biotechnology
Competitive immunoassay
Electrochemical immunosensor
Electrochemistry
Fundamental and applied biological sciences. Psychology
Immunoassay
Magnetic beads
Magnetics
Milk - chemistry
Milk samples
Sulfonamide
Sulfonamides - analysis
Sulfonamides - immunology
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Summary:A novel electrochemical immunosensing strategy for the detection of sulfonamide antibiotics in milk based on magnetic beads is presented. Among the different strategies for immobilizing the class-specific anti-sulfonamide antibody to the magnetic beads – such as those based on the use of Protein A or carboxylate modified magnetic beads – ,the best strategy was found to be the covalent bonding on tosyl-activated magnetic beads. The immunological reaction for the detection of sulfonamide antibiotics performed on the magnetic bead is based on a direct competitive assay using a tracer with HRP peroxidase for the enzymatic labelling. After the immunochemical reactions, the modified magnetic beads can be easily captured by a magneto sensor made of graphite–epoxy composite (m-GEC), which is also used as the transducer for the electrochemical immunosensing. The electrochemical detection is thus achieved through a suitable substrate for the enzyme HRP and an electrochemical mediator. The electrochemical approach is also compared with a novel magneto-ELISA with optical detection. The performance of the electrochemical immunosensing strategy based on magnetic beads was successfully evaluated using spiked milk samples, and the detection limit was found to be 1.44 μg L −1 (5.92 nmol L −1) for raw full cream milk. This strategy offers great promise for rapid, simple, cost-effective and on-site analysis of biological, food and environmental samples.
ISSN:0956-5663
1873-4235
DOI:10.1016/j.bios.2006.10.014