The application of antibodies in immunosensing

This report presents some of the results of the BETA project concerning immobilization of antibodies on sensor materials. An antibody against human Gorionic Gonadotropin (anti-hCG) was immobilized on glass, quartz, silicon and different metallic surfaces. Kinetic measurements of binding of anti-hCG and hCG to different metals were carried out with the surface plasmon resonance (SPR) technique. Immobilization of the antibody, covalently on the different surfaces, was done either by epoxylation or by aminosilanization, followed by glutaraldehyde activation. The binding constants of the antibody were compared with these of the same antibody adsorbed on polystyrene. The activity of the antibody, found on the solid surfaces, was sufficiently high for use in conventional immunoassays (RIA and IRMA). It was also concluded that immunosensing, with SPR, is feasible. However, the coating methods should be still further developed to improve the detection sensitivity and to suppress non-specific binding and crossreactions. Also the detection sensitivity of the used SPR equipment should be enhanced.