Study and development of plasmonic biosensors for biomedical applications

This dissertation presents the design, fabrication, and characterization of photonic crystal (PC) and plasmonic nanostructures, both of which employ the resonantly enhanced near-field effect for biosensing applications. The near-field enhancement around PC surfaces is exploited to increase fluorescence emission from the surface-bound fluorescent species. The same phenomenon can be applied to the resonant excitation of the vibrational modes of molecules adsorbed on the surface of plasmonic nanostructures, thus enhancing Raman signal intensity. The optical properties of PC and plasmonic nanostructures are respectively engineered to appropriate spectral positions in order to maximize signal output. Both nanostructures are inexpensively and uniformly fabricated over large surface areas upon flexible plastic substrates by nanoreplica molding. In addition to detailing and describing PC enhanced fluorescence (PCEF), this dissertation is mainly concerned with the study and development of highly effective surface-enhanced Raman scattering (SERS) substrates and their potential applications in detection and identification of intravenous drugs. Chapter 1 provides a general introduction to the Raman scattering and a brief overview of the SERS mechanism. Chapter 2 shows the work on PCEF through the use of two distinct PC resonances and a high surface-area nanorod coating deposited by the glancing angle deposition (GLAD) technique. Chapter 3 describes the work on the development and characterization of GLAD-deposited SiO2–Ag “post-cap” nanostructures for SERS. Although a high density coating of dielectrically isolated metallic nanoparticles fabricated by the GLAD technique provides a decent SERS enhancement factor (EF) without the need for costly patterning approaches, the optical characteristics of such randomly roughened surfaces are intrinsically difficult to predict and control. In Chapter 4, a plasmonic nanodome array (PNA) structure is designed and developed to overcome this problem. The optical properties and SERS performances of the PNA substrates with superstrates of air and water are investigated. Lastly, Chapter 5 describes the SERS-active PNA surface incorporated into a miniature flow cell connected to biomedical tubing as an in-line SERS sensor for point-of-care detection and real-time monitoring of intravenously delivered drugs.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Electrical & Computer Engr

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2013

Author dc:creator

• Wu, Hsin-Yu

Contributors dc:contributor

• Cunningham, Brian T.
• Jin, Jianming
• Lu, Yi
• Liu, Gang Logan

• Optical sensing and sensors
• Photonic crystal
• Enhanced fluorescence
• Plasmonics
• Localized surface plasmon resonance (LSPR)
• Surface-enhanced Raman scattering (SERS)

Statement dc:rights

• Copyright 2013 Hsin-Yu Wu

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/44747

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/44747