Fiber Optic-Based Immunosensors: A Progress Report

Suresh K. Bhatia; Richard B. Thompson; Lisa C. Shriver-Lake; Michael Levine; Frances S. Ligler

doi:10.1117/12.951556

17 May 1989 Fiber Optic-Based Immunosensors: A Progress Report

Suresh K. Bhatia, Richard B. Thompson, Lisa C. Shriver-Lake, Michael Levine, Frances S. Ligler

Proceedings Volume 1054, Fluorescence Detection III; (1989) https://doi.org/10.1117/12.951556
Event: OE/LASE '89, 1989, Los Angeles, CA, United States

Abstract

Immobilization of functional antibodies on optical fibers at high density and configuration of optical components so as to maximize the signal/noise (S/N) are key elements in the development of fiber optic-based immunosensors. Functional antibodies were immobilized on silica substrates using thiol-terminal silanes and heterobifunctional crosslinkers. Anti-IgG antibody was routinely immobilized on glass cover slips at 0.66 ng/mm2 and on silica fibers at 0.96 ng/mm2 using this procedure. The immobilized antibody bound 0.37-to-0.55 moles IgG antigen per mole antibody. In addition, the amount of protein nonspecifically adsorbed to the antibody-coated surface was only 2-6% of the total antigen binding. Initial assessments of antibody immobilization and function were performed using radiolabelled proteins. In order to convert the system to fluorescence, antigens were labelled with a variety of fluorophores and optical components were tested in a variety of configurations. Problems with background fluorescence were identified stemming from fluorescence of the glass substrates, stickiness of fluorescent proteins, and fluorescence from optical components. The latter problem was addressed by testing a variety of components and configurations in a sensor testbed to determine which provided the greatest sensitivity. Using this iterative approach, we were able to identify factors which degrade sensitivity and to detect 100 pM fluorophor in a distal cuvette configuration with S/N of 14.

Citation Download Citation

Suresh K. Bhatia, Richard B. Thompson, Lisa C. Shriver-Lake, Michael Levine, and Frances S. Ligler "Fiber Optic-Based Immunosensors: A Progress Report", Proc. SPIE 1054, Fluorescence Detection III, (17 May 1989); https://doi.org/10.1117/12.951556

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