AVS 49th International Symposium
    Biomaterials Wednesday Sessions
       Session BI-WeP

Paper BI-WeP18
A Novel Approach for the Detection of Antibiotics using Mixed SAMs of Thiols on Gold

Wednesday, November 6, 2002, 11:00 am, Room Exhibit Hall B2

Session: Biointerfaces and Surfaces II
Presenter: K. Bonroy, IMEC, Belgium
Authors: K. Bonroy, IMEC, Belgium
F. Frederix, IMEC, Belgium
P. Cliquet, University of Ghent, Belgium
W. Laureyn, IMEC, Belgium
A. Campitelli, IMEC, Belgium
G. Borghs, IMEC, Belgium
E. Cox, University of Ghent, Belgium
P. Declerck, KULeuven, Belgium
Correspondent: Click to Email
In numerous applications in the clinical, environmental and toxicological field, there is an increasing need for the detection of low concentrations of different biochemical parameters with low molecular weight. For example, the detection of antibiotic residues in milk is important because of the potential toxic and allergic effect for humans. Immunosensors have a huge potential as a fast and reliable system for the detection of such low molecular weight analytes. Our research is not only focussing on the transducer part of a biosensor, but also on the biological recognition layer. This biological recognition layer mainly determines the specificity, stability, reproducibility and durability of the biosensor. For the detection of small molecules, different assay principles are possible. In the current study an indirect competitive assay was used. Therefore antibiotics were immobilised on the sensor surface and the optimal concentration of a monoclonal antibody (directed against b-lactam antibiotics), allowing quantification of antibiotics, was established.@footnote 1@ For this competitive method, a reproducible and tuneable immobilisation of the antibiotics on the sensor-surface is indispensable. In order to realise such an immunosensor we coupled the antibiotics covalently to mixed Self-Assembled Monolayers (SAMs) of thiols deposited on gold. These mixed SAMs consist of two different thiols: one to bind the antibiotics and another thiol component to avoid non-specific adsorption 2. The binding of the antibiotics on mixed SAMs was characterised with cyclic voltammetry and GA-FTIR and the competitive immunoassay was evaluated using Surface Plasmon Resonance. In conclusion, we have developed a competitive immunoassay for the detection of antibiotics using a biosensor interface based on mixed SAMs of thiols. @FootnoteText@ @footnote1@ Cliquet P. et al. (2001).Journal Agricultural Food Chemistry, 49, 3349-3355@footnote 2@ Frederix F. et al. (2001).European Conference Organised Films, P11.03.