Graduation Term

2024

Degree Name

Master of Science (MS)

Department

Department of Chemistry

Committee Chair

Jeremy Driskell

Abstract

Many current diagnostic tools for accurate disease detection and quantification are often tedious and involve multiple complex steps. Consequently, there is a critical need for alternative point-of-care devices that are affordable and deliver rapid and reliable results. Recently, surface-enhanced Raman spectroscopy (SERS) has emerged as a highly effective analytical method, enhancing Raman scattering of molecules adsorbed onto nanoparticles and allowing for low-level detection and quantitative chemical analysis. In this study, we employ SERS to develop a rapid diagnostic test using human immunoglobulin G (hIgG) as a model biomarker because it is abundant in human serum, cheap, readily available, and well-understood. Our vertical flow immunoassay system utilizes filter paper embedded with spherical gold nanoparticles (AuNPs) to create a plasmonic paper. Capture antibodies (anti-human IgG) are immobilized onto this plasmonic paper and inserted into a vertical flow device (syringe filter). Through multiple passages of the sample through the filter paper, the targets (hIgG) are selectively captured by the immobilized capture antibodies, forming an antibody-antigen complex. Functionalized AuNPs with antibodies and Raman reporter molecules serving as extrinsic Raman labels are subsequently passed through the filter paper to label the captured biomarker molecules, forming a sandwich-like geometry with the hIgG captured between the antibodies on the capture substrate and the functionalized AuNP. This arrangement permits plasmonic coupling, and enhances SERS signal generation, enabling highly sensitive biomolecule detection. Notably, this vertical flow method can be completed within 7 minutes, meeting the requirements for rapid point-of-care.

Access Type

Thesis-Open Access

DOI

https://doi.org/10.30707/ETD2024.20240827063556271718.999998

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