DETECTION OF MULTIPLE TOXIC AGENTS USING A PLANAR ARRAY IMMUNOSENSOR

A planar array immunosensor, equipped with a charge-coupled device (CC D) as a detector, was used to simultaneously detect 3 toxic analytes. Wells approximately 2 mm in diameter were formed on glass slides using a photoactivated optical adhesive. Antibodies against staphylococcal enterotoxin B (SEB), ricin, and Yersinia pestis were covalently attach ed to the bottoms of the circular wells to form the sensing surface. R ectangular wells containing chicken immunoglobulin were used as alignm ent markers and to generate control signals. After removing the optica l adhesive, the slides were mounted over a scientific grade CCD operat ing at ambient temperature in inverted (multipin phasing) mode. A two- dimensional graded index of refraction lens at-ray was used to focus t he sensing surface onto the CCD. Solutions of toxins were then placed on the slide. After rinsing, Cy5-labeled antibodies were introduced. T he identity and amount of toxin bound at each location on the slide we re determined by quantitative image analysis. Concentrations as low as 25 ng/mL of ricin, 15 ng/mL of pestis F1 antigen, and 5 ng/mL of SEB could be routinely measured. (C) 1998 Elsevier Science S.A. All rights reserved.