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Virginia Tech

Long-Period Gratings as Immuno-Diagnostic biosensors

Abstract

dc:description.abstract

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.

Degree

thesis:*
Name thesis:degree_name
Master of Science
Level thesis:degree_level
masters
Discipline thesis:degree_discipline
Electrical and Computer Engineering
Department dc:contributor.department
Electrical and Computer Engineering
Grantor dc:publisher
Virginia Tech
Year dc:date.issued
1997

Author and committee

dc:creator, dc:contributor.*
Author dc:creator
  • D'Alberto, Tiffanie Gabrielle
Chair dc:contributor.committeechair
  • Murphy, Kent A.
Committee members dc:contributor.committeemember
  • Besieris, Ioannis M.
  • Claus, Richard O.

Subjects

dc:subject × 5

Rights

dc:rights
Statement dc:rights
  • In Copyright

Identifiers

dc:identifier.*
Dc Identifier Other
etd-345617310975300
OAI identifier oai:identifier
oai:vtechworks.lib.vt.edu:10919/30480

Chain of custody

source
Harvested from
Virginia Tech
Base URL
vtechworks.lib.vt.edu/oai/request
Last updated
2026-07-22
Source record
OAI-PMH GetRecord
citation

D'Alberto, Tiffanie Gabrielle. Long-Period Gratings as Immuno-Diagnostic biosensors. masters thesis, Virginia Tech, 1997. http://hdl.handle.net/10919/30480