Graduation Year
2024
Document Type
Dissertation
Degree
Ph.D.
Degree Name
Doctor of Philosophy (Ph.D.)
Degree Granting Department
Chemistry
Major Professor
Theresa Evans-Nguyen, Ph.D.
Committee Member
Bill Baker, Ph.D.
Committee Member
Abdul Malik, Ph.D.
Committee Member
Martin Muschol, Ph.D.
Committee Member
Venkat Bhethanabolta, Ph.D.
Keywords
Exosomes, Extracellular vesicles, Lipids, Liposomes, Surface Acoustic Waves
Abstract
Analyzing lipid assemblies, including synthetically produced liposomes and naturally produced extracellular vesicles (EVs), is challenging due to their size, diverse composition, and tendency to aggregate. EVs contain a complex variety of lipids, proteins, and other metabolites. EVs composition can provide us insight into what is happening inside the body and a subcellular level and have potential for noninvasive biomarkers. Liposomes are vesicles that form with a simple phospholipid bilayer membrane and play important roles in drug delivery systems. The use of mass spectrometry (MS) allows for broad analysis of lipids from different classes but their release from the higher order structural aggregates is complicated. Lipids can be difficult to ionize using conventional electrospray ionization (ESI) due to their nonpolar, hydrophobic nature. Current sample preparation methods, including the use of detergents, may not account for the variability of these lipid assemblies. In lieu of these chemical lysing agents, high frequency surface acoustic waves (SAWs) can be utilized to disrupt the lipid bilayer of EVs, releasing its components. In this work, we show that SAWs ability to lyse and fragment lipid assemblies to make them amenable for direct MS analysis. We explore the effects of size and incorporation of nonpolar lipids, including cholesterol, on the SAW’s ability to disrupt liposomes. Optimizing an ionization source suitable for polar and nonpolar lipids using surface acoustic wave nebulization (SAWN) coupled to corona discharge (CD). Here we propose a novel sample preparation using SAWs to disrupt EVs and utilizing ion mobility for separation prior to MS analysis. We aim to identify released lipids from EVs using MS, characterizing SAWs effects on EVs by using scanning electron microscopy (SEM) to study morphological changes of SAWs, and UV-Vis to quantify RNA content released from EVs following disruption.
Scholar Commons Citation
Taylor, Ashton N., "Acoustic Energy for use in Mass Spectrometry" (2024). USF Tampa Graduate Theses and Dissertations.
https://digitalcommons.usf.edu/etd/11204
