Sensor chip preparation and assay construction for immunobiosensor determination of beta-agonists and hormones

Immuno-sensing with optical biosensors is a new technique that is currently being exploited for detection of residues in foods. The present study explores the possibilities of obtaining fast screening assays for a number of illegal veterinary drug residues at low concentrations. Analyte specific sensor surfaces were prepared and used to construct inhibition assays with various antibody reagents. Assay sensitivities for calibration curves in buffer solutions around 0.5 ng ml(-1) in terms of IC50 (concentration of the inhibitor) values were achieved for the beta-agonist clenbuterol and the hormone analogues ethinylestradiol and trenbolone. Assay performance was optimised by evaluating factors such as sensor surface ligand density, active antibody concentration, biosensor flow rate, etc.