Ionic Self-Assembled Multilayers Adsorbed on Long Period Fiber Gratings for Use as Biosensors

dc.contributor.authorWang, Zhiyongen
dc.contributor.committeecochairHeflin, James R.en
dc.contributor.committeecochairStolen, Roger Hallen
dc.contributor.committeememberSafaai-Jazi, Ahmaden
dc.contributor.committeememberPoon, Ting-Chungen
dc.contributor.committeememberJacobs, Iraen
dc.contributor.departmentElectrical and Computer Engineeringen
dc.date.accessioned2014-03-14T20:19:59Zen
dc.date.adate2005-12-27en
dc.date.available2014-03-14T20:19:59Zen
dc.date.issued2005-12-06en
dc.date.rdate2006-12-27en
dc.date.sdate2005-12-08en
dc.description.abstractBiosensors have widespread applications in many areas. Currently the Surface Plasmon Resonance (SPR) biosensor is one of the most prevalent types of biosensor. However, it has several disadvantages such as being delicate, expensive, and non-portable. Ionic Self-Assembled Multilayers (ISAMs) adsorbed on Long Period Fiber Gratings (LPGs) provides an attractive platform for building optical sensors, which could potentially overcome the disadvantages of SPR biosensors. The ISAM technique is a type of layer-by-layer deposition technique for building nanoscale thin films. An LPG is a type of fiber device that is sensitive to physical property changes of the ambient environment. LPGs have been extensively investigated for use as optical sensors. We have carried out a study on combining these two techniques to build efficient biosensors. In this thesis, we demonstrate ultra-sensitive LPGs whose attenuation can be changed by 25 dB (~99.7%) over a 48-nm spectral band, with ambient-index changes of only 2.7E-4. The device schematic allows arbitrarily high index sensitivities to be achieved, which makes it an attractive platform for realizing sensors and modulators that respond to small index changes. For a thin-film coated LPG, we find theoretically that the resonant wavelength shift of the LPG can result from either the variation of the thickness of the film and/or the variation of its refractive index. Furthermore, results illustrate that the sensitivity of the sensor could be enhanced using a nm-thick thin-film (e.g. ISAM films) whose refractive index is greater than silica. Experimentally, we demonstrate the fabrication of nm-thick ISAM films deposited on LPGs, which induces dramatic shifts in the resonant wavelength. The refractive index and the thickness of the ISAM film was precisely controlled by altering the relative fraction of the anionic and cationic materials combined with layer-by-layer deposition. Finally, we demonstrate that ISAM-coated LPGs can function effectively as biosensors by using the biotin-streptavidin system. These demonstrations confirm that the ISAM-LPG scheme provides a thermally-stable, reusable, and robust platform for building efficient optical sensors.en
dc.description.degreePh. D.en
dc.identifier.otheretd-12082005-094018en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-12082005-094018/en
dc.identifier.urihttp://hdl.handle.net/10919/29994en
dc.publisherVirginia Techen
dc.relation.haspartDissertation_ETD_Wang.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectOptical Sensorsen
dc.subjectFiber Opticsen
dc.subjectBiosensoren
dc.subjectLong Period Fiber Gratingen
dc.subjectIonic Self-Assembled Multilayersen
dc.subjectNanometer-thick Thin Filmsen
dc.titleIonic Self-Assembled Multilayers Adsorbed on Long Period Fiber Gratings for Use as Biosensorsen
dc.typeDissertationen
thesis.degree.disciplineElectrical and Computer Engineeringen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.leveldoctoralen
thesis.degree.namePh. D.en
Files
Original bundle
Now showing 1 - 1 of 1
Loading...
Thumbnail Image
Name:
Dissertation_ETD_Wang.pdf
Size:
1.8 MB
Format:
Adobe Portable Document Format