2026-09-19T19:37:13Z https://www.ideals.illinois.edu/oai-pmh

oai:www.ideals.illinois.edu:2142/42166 2023-07-11 col_2142_5131 col_2142_8888 com_2142_5130 com_2142_8887 com_2142_234

Cunningham, Brian T. Cunningham, Brian T. Popescu, Gabriel Liu, Gang Logan Eden, James G. Chaudhery, Vikram 2013-02-03T19:18:04Z 2013-02-03T19:18:04Z 2015-02-03T11:00:57Z 2012-12 2013-02-03T19:18:04Z 2012-12 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. 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). No. of bitstreams: 2 Vikram_Chaudhery.pdf: 19815857 bytes, checksum: 95d04fb7cb3b11f3c33954556789c623 (MD5) license.txt: 4066 bytes, checksum: bce0c75dbf7faf93c81d8d0b206dfb7f (MD5) Restriction data tranferred 2014-07-01T11:11:58-05:00 Original Data Group with Access UIUC Users [automated] Release Date: 2015-02-03 13:18:53 UTC Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD system Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Seth Robbins (srobbins@illinois.edu) on 2013-02-03T19:19:06Z Item is restricted until 2015-02-03T19:18:53Z U of I Only Restriction Lifted for Item 42113 on 2015-02-03T11:00:57Z. http://hdl.handle.net/2142/42166 en Copyright 2012 Vikram Chaudhery Photonic Crystal Enhanced Fluorescence Protein Microarray Cancer Biomarker Next generation instrumentation for photonic crystal biosensors: a passage to early detection of cancer text Electrical & Computer Eng 1933 Electrical & Computer Engr 1200 University of Illinois at Urbana-Champaign Dissertation Ph.D. PHD:Electr & Computer Eng-UIUC 10KS1200PHD