{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/42166"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/42166","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Next generation instrumentation for photonic crystal biosensors: a passage to early detection of cancer","abstract":"The work presented in this dissertation addresses the need for an affordable point-of-care diagnostic tool for early detection of cancer. We identified a biomarker detection approach done using photonic crystal enhanced fluorescence (PCEF) instrumentation as the best way to achieve this goal. We introduce a model for predicting enhanced fluorescence (EF) performance of a photonic crystal (PC) in the context of a given set of instrument parameters as well as insights into instrument specific device design. From this we conclude that PCEF performance is a combined effect of the PC quality-factor (Q-factor) and the instrument angle of divergence. From a practical standpoint, a higher Q-factor gives a higher fluorescence enhancement but at the cost of higher variability in the fluorescence enhancement. To combat this we introduce a new angle-scanning scheme that addresses any uniformity issues. The resulting fluorescence enhancement is recorded to be >600× on a PC with respect to glass. The PC properties are further exploited to introduce a new label-free modality that allows for selective fluorescence enhancement as well as quality control for a protein microarray, helping to identify discrepancies in binding densities of antibodies. The angle-scanning technique coupled with the new modality shows a significant reduction in the coefficient of variation by 20-99% compared to ordinary fluorescence microscopy and a lowering of the detectable biomarker concentrations. To further lower the detection limits and miniaturize the instrument size, the collimated illumination scheme was replaced by a line-focused scheme. The novel PC line-scanning method exploited the optical properties of a one-dimensional PC without significantly sacrificing the coupling efficiency. The higher power density of the approach relative to the collimated PCEF instrument resulted in improved detection limits. A compact objective-coupled design was introduced to address the size demands of an ideal point-of-care system. The biomarker detection study comparing the line-scanning instrument performance with a commercial confocal scanner showed a >10× improvement in the detectable concentrations. Finally, in order to diversify the applicability of the objective coupled system, we modified the setup to incorporate a Raman detection scheme. A PC sensor with sparse surface distribution of gold nanorods was then coated with a monolayer of 4,4’-dipyridyl. The measured Raman scattering signal showed a 7× enhancement between the on and off-resonance cases.","abstract_html":"The work presented in this dissertation addresses the need for an affordable point-of-care diagnostic tool for early detection of cancer. We identified a biomarker detection approach done using photonic crystal enhanced fluorescence (PCEF) instrumentation as the best way to achieve this goal. We introduce a model for predicting enhanced fluorescence (EF) performance of a photonic crystal (PC) in the context of a given set of instrument parameters as well as insights into instrument specific device design. From this we conclude that PCEF performance is a combined effect of the PC quality-factor (Q-factor) and the instrument angle of divergence. From a practical standpoint, a higher Q-factor gives a higher fluorescence enhancement but at the cost of higher variability in the fluorescence enhancement. To combat this we introduce a new angle-scanning scheme that addresses any uniformity issues. The resulting fluorescence enhancement is recorded to be >600× on a PC with respect to glass. The PC properties are further exploited to introduce a new label-free modality that allows for selective fluorescence enhancement as well as quality control for a protein microarray, helping to identify discrepancies in binding densities of antibodies. The angle-scanning technique coupled with the new modality shows a significant reduction in the coefficient of variation by 20-99% compared to ordinary fluorescence microscopy and a lowering of the detectable biomarker concentrations. To further lower the detection limits and miniaturize the instrument size, the collimated illumination scheme was replaced by a line-focused scheme. The novel PC line-scanning method exploited the optical properties of a one-dimensional PC without significantly sacrificing the coupling efficiency. The higher power density of the approach relative to the collimated PCEF instrument resulted in improved detection limits. A compact objective-coupled design was introduced to address the size demands of an ideal point-of-care system. The biomarker detection study comparing the line-scanning instrument performance with a commercial confocal scanner showed a >10× improvement in the detectable concentrations. Finally, in order to diversify the applicability of the objective coupled system, we modified the setup to incorporate a Raman detection scheme. A PC sensor with sparse surface distribution of gold nanorods was then coated with a monolayer of 4,4’-dipyridyl. The measured Raman scattering signal showed a 7× enhancement between the on and off-resonance cases.","abstract_has_math":false,"creators":["Chaudhery, Vikram"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Electrical & Computer Engr","degree_department":null,"school":null,"contributors":["Cunningham, Brian T.","Popescu, Gabriel","Liu, Gang Logan","Eden, James G."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2013,"date_issued":"2013-02-03T19:18:04Z","date_published":"2013-02-03T19:18:04Z","updated_at":"2026-07-22T22:25:31Z","subjects":["Photonic Crystal","Enhanced Fluorescence","Protein Microarray","Cancer Biomarker"],"languages":["en"],"rights":["Copyright 2012 Vikram Chaudhery"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/42166","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Cunningham, Brian T.","Popescu, Gabriel","Liu, Gang Logan","Eden, James G."]},{"key":"dc:creator","label":"Author","values":["Chaudhery, Vikram"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2013-02-03T19:18:04Z","2015-02-03T11:00:57Z","2012-12"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Electrical & Computer Engr"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Photonic Crystal","Enhanced Fluorescence","Protein Microarray","Cancer Biomarker"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2012 Vikram Chaudhery"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/42166"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["The work presented in this dissertation addresses the need for an affordable point-of-care diagnostic tool for early detection of cancer. 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A compact objective-coupled design was introduced to address the size demands of an ideal point-of-care system. The biomarker detection study comparing the line-scanning instrument performance with a commercial confocal scanner showed a >10× improvement in the detectable concentrations. Finally, in order to diversify the applicability of the objective coupled system, we modified the setup to incorporate a Raman detection scheme. A PC sensor with sparse surface distribution of gold nanorods was then coated with a monolayer of 4,4’-dipyridyl. The measured Raman scattering signal showed a 7× enhancement between the on and off-resonance cases.","Item withdrawn by Mark Zulauf (zulauf@illinois.edu) on 2012-11-26T14:34:16Z Item was in collections: University of Illinois Theses & Dissertations (ID: 1) No. of bitstreams: 1 Chaudhery_Vikram.pdf: 19794840 bytes, checksum: e94215bc173018068de15b5b04e061d4 (MD5)","Made available in DSpace on 2013-02-03T19:18:04Z (GMT). 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The PC properties are further exploited to introduce a new label-free modality that allows for selective fluorescence enhancement as well as quality control for a protein microarray, helping to identify discrepancies in binding densities of antibodies. The angle-scanning technique coupled with the new modality shows a significant reduction in the coefficient of variation by 20-99% compared to ordinary fluorescence microscopy and a lowering of the detectable biomarker concentrations. To further lower the detection limits and miniaturize the instrument size, the collimated illumination scheme was replaced by a line-focused scheme. The novel PC line-scanning method exploited the optical properties of a one-dimensional PC without significantly sacrificing the coupling efficiency. The higher power density of the approach relative to the collimated PCEF instrument resulted in improved detection limits. A compact objective-coupled design was introduced to address the size demands of an ideal point-of-care system. The biomarker detection study comparing the line-scanning instrument performance with a commercial confocal scanner showed a >10× improvement in the detectable concentrations. Finally, in order to diversify the applicability of the objective coupled system, we modified the setup to incorporate a Raman detection scheme. A PC sensor with sparse surface distribution of gold nanorods was then coated with a monolayer of 4,4’-dipyridyl. The measured Raman scattering signal showed a 7× enhancement between the on and off-resonance cases.","Item withdrawn by Mark Zulauf (zulauf@illinois.edu) on 2012-11-26T14:34:16Z Item was in collections: University of Illinois Theses & Dissertations (ID: 1) No. of bitstreams: 1 Chaudhery_Vikram.pdf: 19794840 bytes, checksum: e94215bc173018068de15b5b04e061d4 (MD5)","Made available in DSpace on 2013-02-03T19:18:04Z (GMT). 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