Optical detection of antibody-antigen reactions at a glass-liquid interface.

摘要: We describe an optical technique for detecting and monitoring antibody-antigen reactions at a solid-liquid interface. The antibody is covalently immobilized onto the surface of either planar (microscope slide) or cylindrical (fibre optic) waveguide made fused quartz. reaction with antigen in solution detected through use evanescent wave component light beam, which has characteristic depth penetration fraction wavelength into aqueous phase, thus optically interacting primarily substances bound (or located very close) to interface only minimally bulk solution. This resulting in-situ spatial separation antibody-bound from free precludes formal step allows be monitored kinetically. An immunoassay methotrexate by absorption spectrometry achieved detection limit about 270 nmol/L; binding was decrease transmittance 310 nm. A two-site immunofluorometric assay human IgG could detect as little 30 fluorescein-labeled increase signal above 520 nm (lambda ex = 495 nm). With both immunoassays signal-generating phase kinetically completed within 15 min.