Electronic Theses and Dissertations

Date

2023

Document Type

Dissertation

Degree Name

Doctor of Philosophy

Department

Chemistry

Committee Chair

Xiaohua Huang

Committee Member

Thang B Hoang

Committee Member

Yongmei Wang

Committee Member

Daniel R Nascimento

Committee Member

Michael A Brown

Abstract

Single vesicle molecular profiling has the potential to transform cancer detection and monitoring by precisely probing cancer-associated exosomes in the presence of normal exosomes in body fluids. However, it is challenging due to the small exosome size, low abundance of antigens on individual exosomes, and complex biological matrix. A facile dual imaging single vesicle technology (DISVT) has been developed and described for surface protein profiling of individual exosomes and quantification of target-specific exosome subtypes in biofluids by integrating multiple components, including direct molecular exosome capture from diluted biofluids, dual exosome-protein light scattering/fluorescence imaging, and fast Python-programing based image analysis. This technology uses strong surface plasmon light scattering properties of gold nanoparticles (AuNPs) to detect targeted surface protein markers with darkfield imaging on exosomes at the single particle level. Meanwhile, fluorescent imaging uses a fluorescent near-infrared dye to localize captured exosomes. A customized microscope achieved dual light scattering/fluorescence imaging. By optimizing various parameters, including concentration, binding time, and binding temperature of the AuNPs and dye, this DISVT can detect targeted surface protein markers of interest at the single vesicle level. Using DISVT, we characterized several protein markers on exosomes derived from several model breast cancer (BC) cells, validating them with standard ELISA. We demonstrated the potential of DISVT for early cancer detection using Human epidermal growth factor receptor 2 (HER2)-positive BC as the disease model by profiling HER2-positive exosomes in plasma from HER2-positive BC patients at multiple stages, comparing them with healthy donors and HER2-negative BC patients. We demonstrated that the DISVT, but not ELISA, detected BC at early stages. The DISVT differentiated HER2-positive- from HER2-negative- BC. The amount of tumor-associated exosomes showed to be tripled in locally advanced- compared to early-stage- patients. Our studies suggest that single exosome surface protein profiling with DISVT can provide a novel and highly sensitive method for early cancer detection and quantitative monitoring. Due to the advantages in simplicity, sample consumption, speed, and cost, this DISVT has the potential to accelerate the translation of exosomes into clinical use, leading to a new generation of liquid biopsy for detecting and monitoring cancer and other diseases.

Comments

Data is provided by the student.

Library Comment

Dissertation or thesis originally submitted to ProQuest

Notes

Open Access

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