Highly sensitive biosensors using photonic crystal enhanced fluorescence

Tan, Yafang

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https://hdl.handle.net/2142/73064 Copy

Description

Title

Highly sensitive biosensors using photonic crystal enhanced fluorescence

Author(s)

Tan, Yafang

Issue Date

2015-01-21

Director of Research (if dissertation) or Advisor (if thesis)

Cunningham, Brian T.

Doctoral Committee Chair(s)

Cunningham, Brian T.

Committee Member(s)

• Gong, Songbin
• Liu, Gang
• Vodkin, Lila O.

Department of Study

Electrical & Computer Eng

Discipline

Electrical & Computer Engr

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• Photonic Crystal Enhanced Fluorescence (PCEF)
• Immunoassays
• Molecular beacon assays

Abstract

Due to the importance of fluorescence assays in clinics, life science and genomic research, many nanostructures have been proposed to enhance the weak fluorescence signals from low abundance analytes. Among these structures, photonic crystal (PC) has attracted particular attentions because of its capability to produce high electric fields without quenching fluorescence emission. Properly designed PC surface can efficiently couple laser illumination to fluorescent dye molecules (enhanced excitation) and meanwhile effectively collects fluorescence emission (enhanced extraction). In this dissertation, photonic crystal enhanced fluorescence (PCEF) was used for disease biomarker dissertation. We applied PCEF to multiplexed microspot immunoassays for detection of allergen-specific antibodies. The PCEF system was able to detect low concentrations of Fel d1 specific IgE ~0.02 kU/L, which is 5-fold to 17-fold more sensitive than the commercially available FDA-approved analyzers. We also aimed to improve the current platform by incorporating a PC surface with a microfluidic chip in order to enable a rapid and automatic biomarker analysis at microliter sample consumption. We fabricated a plastic microfluidic device for holding the PC using a low-cost and flexible process and developed a leak-free automation system to introduce the correct sequence of fluids through the microfluidic device. The PCEF platform was successfully automated to enable more rapid, high sensitivity detection and a simplified output that will be readily usable by a clinician. Besides microarray immunoassays, the PCEF platform was also adapted to a molecular beacon assay for miRNA detection, where the PC surface was incorporated with a submicron-height fluid channel. The use of the PCEF platform results in a reduction of the detection limits and an increase in the signal-to-noise ratio (SNR) with a small, inexpensive detection instrument.

Graduation Semester

2014-12

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http://hdl.handle.net/2142/73064

Copyright and License Information

Copyright 2014 Yafang Tan

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