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 expl ores the possibilities of obtaining fast screening assays for a number of i llegal veterinary drug residues at low concentrations. Analyte specific sen sor surfaces were prepared and used to construct inhibition assays with var ious antibody reagents. Assay sensitivities for calibration curves in buffe r solutions around 0.5 ng ml(-1) in terms Of IC50 (Concentration of the inh ibitor) values were achieved for the beta -agonist clenbuterol and the horm one analogues ethinylestradiol and trenbolone. Assay performance was optimi sed by evaluating factors such as sensor surface ligand density, active ant ibody concentration, biosensor flow rate, etc.