He, Xiaoyun
(2022)
Photoluminescence Properties of Carbon Nanomaterials during Coronation and Biodegradation.
Doctoral Dissertation, University of Pittsburgh.
(Unpublished)
Abstract
Carbon nanomaterials (CNMs) have been widely used in biomedical applications such as drug delivery, biosensing, and bioimaging. Due to their interactions with the biological systems in these applications, it is important to understand what happens to CNMs in vivo. Upon introduction into a biological environment, CNMs are rapidly coated with biomolecules (90% lipids) resulting in so-called ‘biocorona’. CNMs can also undergo additional bio-transformations including partial or complete biodegradation. This dissertation focuses on using fluorescence spectroscopy to study the chemical reactions between CNMs and different biomolecules upon coronation and biodegradation.
We first use fluorescence spectroscopy to study the reactions between the single-walled carbon nanotubes (SWCNTs) and the biologically important oxygenated lipid metabolites. A photoinduced cycloaddition reaction between metabolites bearing enone functional groups and SWCNTs is reported here. By creating covalent and tunable sp3 defects in the sp2 carbon lattice of SWCNTs through [2π + 2π] photocycloaddition, a bright red-shifted photoluminescence (PL) was gradually generated. The mechanism of the photocycloaddition reaction was further investigated by comparing the reactivity with various organic molecules and computational calculations. The results of this study can enable engineering of the optical and electronic properties of semiconducting SWCNTs and provide understanding into their interactions with the lipid biocorona.
In addition to coronation, CNMs could induce a robust inflammatory response. Our research group has found that these effects can be mitigated by enzymatic biodegradation of CNMs through a peroxidase enzyme released by neutrophils during inflammation, myeloperoxidase (MPO). We performed PL studies on the MPO-catalyzed oxidation of graphene oxide (GO) and surfactant-coated SWCNTs. We further constructed two ratiometric sensors using SWCNT/GO nanoscrolls by incorporating surfactant-wrapped SWCNTs as the internal either turn-off or reference sensor. Our sensors show linear response to MPO oxidative machinery and hold the promise to be used as self-calibrating CNMs-based MPO activity indicators. Finally, the composition and structures of the fluorescent GO degradation products, in the form of polyaromatic hydrocarbons (PAHs), were analyzed using liquid chromatography–mass spectrometry and computational calculations. Our results indicated that structures with several conjugated benzene rings are likely to generate the observed PL.
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Details
| Item Type: |
University of Pittsburgh ETD
|
| Status: |
Unpublished |
| Creators/Authors: |
|
| ETD Committee: |
| Title | Member | Email Address | Pitt Username | ORCID |
|---|
| Committee Chair | Alexander, Star | | | | | Committee Member | Steve, Weber | | | | | Committee Member | Haitao, Liu | | | | | Committee Member | Michael, R. Shurin | | | |
|
| Date: |
24 February 2022 |
| Date Type: |
Publication |
| Defense Date: |
8 September 2021 |
| Approval Date: |
24 February 2022 |
| Submission Date: |
15 October 2021 |
| Access Restriction: |
No restriction; Release the ETD for access worldwide immediately. |
| Number of Pages: |
241 |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Dietrich School of Arts and Sciences > Chemistry |
| Degree: |
PhD - Doctor of Philosophy |
| Thesis Type: |
Doctoral Dissertation |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
photoluminescence, carbon nanomaterials, coronation, biodegradation |
| Date Deposited: |
24 Feb 2022 15:28 |
| Last Modified: |
24 Feb 2022 15:28 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/41858 |
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