On the Physicochemical Characteristics and Biological Effects of Derivatized Fullerene and Synthesis By-Products

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Material Information

Title:
On the Physicochemical Characteristics and Biological Effects of Derivatized Fullerene and Synthesis By-Products
Physical Description:
1 online resource (278 p.)
Language:
english
Creator:
Indeglia,Paul Anthony
Publisher:
University of Florida
Place of Publication:
Gainesville, Fla.
Publication Date:

Thesis/Dissertation Information

Degree:
Doctorate ( Ph.D.)
Degree Grantor:
University of Florida
Degree Disciplines:
Environmental Engineering Sciences
Committee Chair:
Bonzongo, Jean-Claud
Committee Members:
Kopelevich, Dmitry I
Lindner, Angela S
Svoronos, Spyros
Moudgil, Brij M

Subjects

Subjects / Keywords:
Environmental Engineering Sciences -- Dissertations, Academic -- UF
Genre:
Environmental Engineering Sciences thesis, Ph.D.
Electronic Thesis or Dissertation
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )

Notes

Abstract:
This investigation examined the physicochemical characteristics and biological effects of fullerene derivatives, nC60 and fullerenol (C60HzOx(OH)y), and their synthesis by-products to assess mechanisms of and factors influencing biological effects. Physicochemical analyses of derivatized fullerene included molecular and agglomerate-scale characterization by dynamic light scattering (DLS) and transmission electron scattering (TEM), surface charge through electrophoretic analysis of mobility, and chemical composition analysis using ultraviolet/visible light (UV/Vis), Fourier-transform infrared (FTIR), and X-ray photoelectron spectroscopy (XPS). Detailed analysis of nC60 transformation over a 28-day stirring period indicated nC60 agglomerate concentrations can be estimated as a function of time by using a predictor model (R2 > 0.99). Agglomerate sizes did not differ significantly over the 28-day stirring period regardless of photocondition (DLS: d = 138.2 nm; TEM: d = 110.0 nm) although distributions were more uniform as stirring time increased. The total number of surface groups identified through XPS indicated increased derivatization as a function of time with additions assigned to mono-oxygenated carbon moieties while the number of di-oxygenated moieties declined. Early phase stirring (t ? 14 days) products were shown through FTIR analysis to contain epoxide surface groups, which were absent in later-phase (t > 14 days) samples, suggesting specific pathways to derivatization with preferential mono-oxygenated states. Fullerenol was shown to persist in a molecular state at concentrations below 20 mg/L with increased concentration and sonication causing an increase in agglomerate size. Fullerenol surface group composition varied between three independent synthesis events with the number of total derivatized carbon atoms ranging from 21 to 30 and the number of mono-oxygenated groups ranging from 5 to 20. nC60 agglomerates displayed greater surface derivatization than fullerenol as well as a higher percentage of mono-oxygenated groups. Filter residue, a by-product of nC60 synthesis, demonstrated high hydrophobicity and FTIR spectra similar to underivatized material, although nC60 stirred for 28-days was shown to have nine mono-oxygenated carbons and no di-oxygenated groups. By-products from fullerenol synthesis contained 21 to 30 surface groups and synthesis reactants tetrabutylammonium hydroxide and sodium hydroxide were found in all by-products. Y-products generated through a methanol rinse were shown to contain 21 mono-oxygenated groups with no-di-oxygenated moieties. Biological assays were conducted using two different bacteria (Pseudomonas aeruginosa and Staphylococcus aureus), one algae (Pseudokirchneriella subcapitata), and one invertebrate species (Ceriodaphnia dubia) as model test organisms. The bioassays assessed the effects of derivatized fullerene materials in accordance with commonly-used and widely-accepted ecotoxicity protocols. Dark-exposure bacteria population (chronic) assays were complimented with light-exposure algae population (chronic) and daphnid mortality (acute) assays. The LC50 for nC60 against the Gram-negative bacteria P. aeruginosa was extrapolated to be 1,336 mg/L under dark-exposure conditions; however, no toxicity thresholds were calculable for the Gram-positive S. aureus, the algae P. subcapitata, or the invertebrate C. dubia exposed to nC60 due to insufficient biological effect with concentrations extending to 100 mg/L. The LC50 for bacteria exposed to fullerenol was extrapolated to be 2,409 and > 10,000 mg/L for P. aeruginosa and S. aureus, respectively, and estimated to be 299 and 31.1 mg/L for P. subcapitata and C. dubia, respectively, suggesting fullerenol exhibited greater biological impact when exposed to light. Biological effects from fullerenol synthesis by-products on C. dubia were attributed to residual synthesis reactants and photoactivity of derivatized fullerene contained within the material removed, although neither by-product analyzed caused notable toxicity to unicellular organisms. Mechanisms of cell damage on bacteria populations were investigated using nucleic acid dye assays, concluding that both apoptotic and necrotic responses occurred with and without photoactivation.
Statement of Responsibility:
by Paul Anthony Indeglia.
General Note:
In the series University of Florida Digital Collections.
General Note:
Includes vita.
Bibliography:
Includes bibliographical references.
General Note:
Description based on online resource; title from PDF title page.
General Note:
This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Thesis:
Thesis (Ph.D.)--University of Florida, 2011.
General Note:
Adviser: Bonzongo, Jean-Claud.
General Note:
RESTRICTED TO UF STUDENTS, STAFF, FACULTY, AND ON-CAMPUS USE UNTIL 2014-08-31

Record Information

Source Institution:
UFRGP
Rights Management:
Applicable rights reserved.
Classification:
lcc - LD1780 2011
System ID:
UFE0042862:00001