Document Type

Dissertation

Degree

Doctor of Philosophy (PhD)

Major/Program

Chemistry

First Advisor's Name

Kevin E. O'Shea

First Advisor's Committee Title

Committee chair

Second Advisor's Name

Piero R. Gardinali

Second Advisor's Committee Title

Committee member

Third Advisor's Name

Watson J. Lees

Third Advisor's Committee Title

Committee member

Fourth Advisor's Name

Joong Ho Moon

Fourth Advisor's Committee Title

Committee member

Fifth Advisor's Name

Gary M. Rand

Fifth Advisor's Committee Title

Committee member

Keywords

Perfluoroalkyl substance (PFAS), Cyclodextrin, NMR spectroscopy, Perfluorooctanoic acid (PFOA)

Date of Defense

5-22-2018

Abstract

Perfluoroalkyl substances (PFASs) are contaminants of emerging concern, and have been detected in drinking water, wildlife, humans, and the environment. Cyclodextrins (CDs), cyclic sugars composed of glucose monomers, are proposed as a potential remediation strategy. CDs can form host-guest complexes with hydrophobic molecules; this complexation could be capitalized on for PFAS removal and sequestration. These dissertation projects aim to study the fundamental host-guest interactions between a variety of PFASs and CDs for eventual applications in environmental and biological remediation. 1D and 2D Nuclear magnetic resonance (NMR) spectroscopic methods were employed to determine the strength, dynamics, and structure of the CD:PFAS host-guest complexes. Legacy and emerging PFASs were studied with the three native CDs (α-, β-, and γ-CDs) as well as β-CD derivatives. β-CD and its derivatives exhibit the strongest complexation with all studied PFASs, with association constants of 102-105 M-1, depending on PFAS chain length, functional groups, and branching. The host-guest complex was not significantly disturbed under different environmental conditions, such as changing pH, ionic strength, and in the presence of humic acid. A competition study between perfluorooctanoic acid (PFOA), β-CD, and human serum albumin (HSA), the most abundant protein in blood serum, was then conducted using NMR, circular dichroism, and fluorescence spectroscopies. Excess β-CD was able to totally reverse all PFOA binding to HSA. Finally, the host-guest complex was studied within a biological organism to test its viability as a remediation strategy. The attenuation of the toxicity of PFOA in zebrafish embryos, a model organism for toxicology studies, was tested with β-CD. Excess β-CD increased the LC50 (lethal concentration for 50 % of the population) of PFOA compared to PFOA in the absence of β-CD (p < 0.0001). These dissertation projects suggest that the encapsulation of PFASs by CDs has potential in PFAS remediation strategies.

Identifier

FIDC006877

ORCID

0000-0002-1745-8136

Available for download on Friday, July 19, 2019

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