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Long-Period Gratings as Immuno-Diagnostic biosensors

This research presents a novel biosensor which utilizes the refractive index sensitivity of a fiber optic long-period grating. The long period grating couples light from the forward propagating guided core mode of a single-mode fiber into discrete circularly symmetric cladding modes. Due to imperfections in the cladding surface, loss bands are seen in the transmission spectrum corresponding to the coupled wavelengths. Based on the phase-matching condition between the coupling and coupled modes, the loss bands shift with changes in the refractive index of the surrounding medium. The grating surface is chemically treated to covalently bond antibody to the cladding of the sensor. Treatment with the proper antigen increases the effective index seen by the cladding modes and affects the placement of the loss bands. This sensor demonstrates specific antigen binding capacity with loss band shifts of 10 nm or more. The device offers several advantages over the widely used Enzyme-Linked Immuno-Sorbent Assays. Diagnostic applications can be expanded beyond the tests presented here. / Master of Science

Identiferoai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/30480
Date27 January 1997
CreatorsD'Alberto, Tiffanie Gabrielle
ContributorsElectrical and Computer Engineering, Murphy, Kent A., Besieris, Ioannis M., Claus, Richard O.
PublisherVirginia Tech
Source SetsVirginia Tech Theses and Dissertation
Detected LanguageEnglish
TypeThesis
Formatapplication/pdf
RightsIn Copyright, http://rightsstatements.org/vocab/InC/1.0/
Relationthesis.pdf

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