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

Abstract

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

Anti‐Dengue‐Virus Activity and Structure–Activity Relationship Studies of Lycorine Derivatives

“…An immunosensor based on the BLM transduction scheme should be regenerated and be able to be used in multiple analyses. A limited number of immunosensors have been reported in the literature in which the active sites of the antibody are regenerated by placing the device in acidic 22, 23 or in chaotropic media 24.…”

The Development of Highly Sensitive and Selective Immunosensor Based on Antibody Immobilized ZnO Nanorods for the Detection of D‐Dimer

“…An immunosensor based on the BLM transduction scheme should be regenerable and capable of multiple analyses. A number of immunosensors have been regenerated by placing the device in acidic 33, 34] or in chaotropic media 35.…”

Stabilized filter‐supported bilayer lipid membranes (BLMs) for automated flow monitoring of compounds of clinical, pharmaceutical, environmental and industrial interest

“…Filter-supported BLMs as electrochemical detectors for flow immunoanalysis A limited number of immunosensors for use in flow injection analysis have recently appeared in the literature [17][18][19][20][21][22]. However, these immunosensors require the use of acidic [23,24] or chaotropic media [25] to regenerate the antibody binding sites which permanently alters the antibody conformation or replacement of the chemistry at the device surface, which is costly and time consuming [17][18][19]. Regeneration of active sites of antibodies without loss of activity has been reported in a few instances by washing with a flowing electrolyte solution (i.e.…”