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Published on: October 23, 2011
DNA-directed immobilization fluorescent immunoarray for multiplexed antibiotic residue determination in milk
J Guercetti1,2, N Pascual1,2, A Aviñó2,3
1Nanobiotechnology for Diagnostics (Nb4D), Department of Chemical and Biomolecular Nanotechnology, Institute for Advanced Chemistry of Catalonia (IQAC), Spanish Council for Scientific Research (CSIC), Jordi Girona 18-26, Barcelona, 08034, Spain.
A new DNA-directed immobilization (DDI) microarray platform rapidly detects antibiotic residues in milk. This cost-effective screening tool identifies fluoroquinolones, sulfonamides, and tylosin, ensuring milk safety and compliance with EU regulations.
Area of Science:
- Analytical Chemistry
- Biotechnology
- Food Safety
Background:
- Antibiotic residues in cow's milk pose significant risks to consumers, the dairy industry, and environmental health.
- There is a critical need for rapid, cost-effective, and sensitive methods to screen for these residues in milk.
- Existing methods may lack the specificity, speed, or cost-efficiency required for widespread screening.
Purpose of the Study:
- To develop a multiplexed screening platform using DNA-directed immobilization (DDI) for detecting three prevalent antibiotic classes in milk: fluoroquinolones, sulfonamides, and tylosin.
- To achieve limits of detection (LODs) below European Union (EU) regulatory limits.
- To validate the platform's performance in classifying milk samples as compliant or non-compliant.
Main Methods:
- A DDI-based microarray chip was designed, immobilizing oligonucleotide sequences conjugated to different haptens.
- The array was incubated with hapten-oligonucleotide conjugates for signal encoding via DNA hybridization.
- Milk samples were analyzed using a cocktail of monoclonal antibodies and a secondary fluorophore-labeled antibody for fluorescent readout.
Main Results:
- The DDI platform successfully detected fluoroquinolones (CIP), sulfonamides (STZ), and tylosin (TYLA) in milk samples diluted 20-fold.
- Achieved LODs were 0.89 µg/kg for CIP, 1.67 µg/kg for STZ, and 1.43 µg/kg for TYLA, all below EU regulatory limits.
- The system demonstrated successful classification of spiked milk samples as compliant or non-compliant, with evaluated cross-reactivity.
Conclusions:
- The developed DDI-based immunoarray offers a fast, cost-effective, and sensitive method for simultaneous semi-quantitative detection of multiple antibiotic residues in milk.
- This platform meets the urgent need for reliable screening tools to ensure milk safety and regulatory compliance.
- The DDI approach provides a valuable alternative for routine monitoring in the dairy industry.
