Title
Chip-scale bioassays based on surface-enhanced Raman scattering: fundamentals and applications
Degree Type
Dissertation
Date of Award
2005
Degree Name
Doctor of Philosophy
Department
Chemistry
First Advisor
Marc D. Porter
Abstract
This work explores the development and application of chip-scale bioassays based on surface-enhanced Raman scattering (SERS) for high throughput and high sensitivity analysis of biomolecules;The size effect of gold nanoparticles on the intensity of SERS is first presented. A sandwich immunoassay was performed using Raman-labeled immunogold nanoparticles with various sizes. The SERS responses were correlated to particle densities, which were obtained by atomic force microscopy (AFM). The response of individual particles was also investigated using Raman-microscope and an array of gold islands on a silicon substrate. The location and the size of individual particles were mapped using AFM;The next study describes a low-level detection of Escherichia coli O157:H7 and simulants of biological warfare agents in a sandwich immunoassay format using SERS labels, which have been termed Extrinsic Raman labels (ERLs). A new ERL scheme based on a mixed monolayer is also introduced. The mixed monolayer ERLs were created by covering the gold nanoparticles with a mixture of two thiolates, one thiolate for covalently binding antibody to the particle and the other thiolate for producing a strong Raman signal;An assay platform based on mixed self-assembled monolayers (SAMs) on gold is then presented. The mixed SAMs were prepared from dithiobis(succinimidyl undecanoate) (DSU) to covalently bind antibodies on gold substrate and oligo(ethylene glycol)-terminated thiol to prevent nonspecific adsorption of antibodies. After the mixed SAMs surfaces, formed from various mole fraction of DSU were incubated with antibodies, AFM was used to image individual antibodies on the surface;The final study presents a collaborative work on the single molecule adsorption of YOYO-I labeled lambda-DNA at compositionally patterned SAMs using total internal reflection fluorescence microscopy. The role of solution pH, lambda-DNA concentration, and domain size was investigated. This work also revealed the potential importance of structural defects.
DOI
https://doi.org/10.31274/rtd-180813-15397
Publisher
Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/
Copyright Owner
Hye-Young Park
Copyright Date
2005
Language
en
Proquest ID
AAI3200452
File Format
application/pdf
File Size
118 pages
Recommended Citation
Park, Hye-Young, "Chip-scale bioassays based on surface-enhanced Raman scattering: fundamentals and applications " (2005). Retrospective Theses and Dissertations. 1765.
https://lib.dr.iastate.edu/rtd/1765