Fiber-optic Fabry-Perot interferometric (FFPI) sensors have been widely used due to their high sensitivity, ease of fabrication, miniature size, and capability for multiplexing. However, direct measurement of self-assembled thin films, receptor immobilization process or biological reaction is limited in the FFPI technique due to the difficulty of forming Fabry-Perot cavities by the thin film itself. Novel methods are needed to provide an accurate and reliable measurement for monitoring the thin-film growth in the nanometer range and under various conditions.
In this work, two types of fiber-optic multicavity Fabry-Perot interferometric (MFPI) sensors with built-in temperature compensation were designed and fabricated for thin-film measurement, with applications in chemical and biological sensing. Both the tubing-based MFPI sensor and microgap MFPI sensor provide simple, yet high performance solutions for thin-film sensing. The temperature dependence of the sensing cavity is compensated by extracting the temperature information from a second multiplexed cavity. This provides the opportunity to examine the thin-film characteristics under different environment temperatures.
To demonstrate the potential of this structure for practical applications, immunosensors were fabricated and tested using these structures. Self-assembled polyelectrolytes served as a precursor film for immobilization of antibodies to ensure they retain their biological activity. This not only provides a convenient method for protein immobilization but also presents the possibility of increasing the binding capacity and sensitivity by incorporating multilayers of antibodies into polyelectrolyte layers. The steady-state measurement demonstrated the surface concentration and binding ratio of the immunoreaction. Analysis of the kinetic binding profile provided a fast and effective way to measure antigen concentration. Monitoring the immunoreaction between commercially available immunoglobulin G (IgG) and anti-IgG demonstrated the feasibility of using the MFPI sensing system for immunosensing applications. / Ph. D.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/30104 |
| Date | 22 December 2005 |
| Creators | Zhang, Yan |
| Contributors | Electrical and Computer Engineering, Wang, Anbo, Heflin, James R., Jacobs, Ira, Safaai-Jazi, Ahmad, Pickrell, Gary R. |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Detected Language | English |
| Type | Dissertation |
| Format | application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
| Relation | dissertation.pdf |
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