Theses and Dissertations

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Open Access
[1,3]-oxygen to carbon rearrangement for the construction of carbon-carbon bonds between adjacent rings and 1,3-dioxepines in synthesis
(Colorado State University. Libraries, 2007) Frein, Jeffrey Daniel, author; Rovis, Tomislav, advisor
Several methods for the stereoselective formation of carbon-carbon bonds between contiguous rings where a stereogenic center is already present have been examined. The approaches investigated were: a [1,3]-oxygen to carbon rearrangement of cyclic vinyl acetals; an intermolecular enolsilane addition into an in situ generated oxocarbenium ion; an intramolecular conjugate addition of tethered alkoxy enones; and epimerization of several Î±-pyranyl cycloalkanones. These routes have been found to be complementary in several cases and have enabled formation of both the traps: anti and cis:anti stereoisomers in good to excellent yields and varying diastereoselectivities. The C2-C2' relative stereochemistry of the carbon-carbon bond between the adjacent rings was proven via a chemical correlation. The versatility of 1,3-dioxepines as precursors to the formation of 1,4-diols and 1,2,4-triols has been examined. The rapid synthesis of unsymmetrical 1,3-dioxepines and the installation of a 4-acetoxy substituent as a synthetic handle for further functionalization has been realized. The Lewis acid mediated addition into in situ generated oxocarbenium ions has been developed for variety of different nucleophiles. Furthermore, a highly trans -diastereoselective Heck reaction has been performed on unsymmetrical 1,3-dioxepines and their synthetic utility as precursors to the formation of 2,3,4-alkyl substituted tetrahydrofurans and 2-methoxy-4,5-alkyl substituted tetrahydrofurans have been exploited.
Open Access
A clonable selenium nanoparticle in action: high resolution localization of FtsZ using electron tomography
(Colorado State University. Libraries, 2021) Borgognoni, Kanda, author; Ackerson, Christopher J., advisor; Neilson, James, committee member; Kennan, Alan J., committee member; Tsunoda, Susan, committee member
A meaningful understanding of biochemistry requires that we understand the function of proteins, which is heavily dependent on their structure and location within an organism. As the Resolution Revolution of cryo-electron microscopy gains unprecedented ground largely due to the recent development of commercially available direct electron detectors, energy filters, and high-end computation, thousands of protein structures have been solved at atomic or near-atomic resolution, with the highest resolution structure to date being solved at 1.2 Å. A major challenge that has limited the broad use of cryo-electron tomography (cryo-ET) is locating a protein of interest in an organism, as no commercially available high-contrast markers which can be generated in vivo exist. Herein, we present a breakthrough study which aims to solve this problem by synthesizing high contrast metal nanoparticles labeling desired proteins in situ. We isolated a Glutathione Reductase-like Metalloid Reductase (GRLMR), which can reduce selenite and selenate into selenium nanoparticles (SeNPs), from Pseudomonas moraviensis stanleyae found in the roots of a Se hyperaccumulator Stanleya pinnata, or Desert Princes' Plume. A recombinant variant, denoted as a clonable Selenium NanoParticle (cSeNP), was fused to filamentous temperature sensitive protein Z (FtsZ), and the chimera was expressed in vivo using a T7 expression system in model organism E. coli for a proof-of-concept study. Because the SeNPs biogenically produced are amorphous, they exist in a quasistable state and are composed of polymeric Sen in the form of chains and rings that are constantly breaking and reforming. To stabilize the particles during cellular preservation ex aqua, a disproportionation-like reaction can be done either in vivo or as a post-fixation step to form crystalline metal selenide (MSe) NPs that can withstand the processing liquids used. Thereafter, electron tomography was used to acquire a tilt series that was reconstructed into a tomogram and segmented using IMOD, generating a model representing MSeNPs labeling FtsZ filaments. As such, we have demonstrated the potential of using cSeNP as a high resolution marker for cryo-ET. While our study relied on traditional preservation and embedment techniques, we anticipate that for cells preserved via vitrification, cloned SeNPs can be used without subsequent transformation to MSeNPs, as the amorphous particles are stable in aqueous media. Prospectively, we expect that clonable nanoparticle technology will revolutionize cryo-ET, allowing us to localize proteins in vivo at high resolution while maintaining organism viability through metal immobilization. Furthermore, this technique can be expanded to other imaging modalities, such as light microscopy and X-ray tomography, through the discovery and engineering of other clonable nanoparticles.
Open Access
A concise total synthesis of the TMC-95A and TMC-95B proteasome inhibitors
(Colorado State University. Libraries, 2004) Albrecht, Brian Keith, author; Williams, Robert M., advisor
A concise total synthesis of the TMC-95A/B proteasome inhibitors is presented. The synthesis features the use of an L-serine derived E-selective modified Julia olefination reaction that ultimately controls the stereochemical outcome of the highly oxidized tryptophan fragment. A diastereoselective dihydroxylation, a Suzuki coupling, macrocyclization and cis-propenyl amide formation were also employed. In the process of the total synthesis, a suitable intermediate was converted to a late stage intermediate in the Danishefsky total synthesis, effectively completing a formal synthesis. The limited use of protecting groups allowed for an efficient route that is amenable to the preparation of a variety of analogs due to its convergency.
Open Access
A divergent synthesis of secologanin derived natural products
(Colorado State University. Libraries, 2010) English, Brandon Joel, author; Williams, Robert M., advisor; Ferreira, Eric M., committee member; Eckstein, Torsten, committee member; Elliot, C. Michael, committee member; Finke, Richard G., committee member
This dissertation documents the racemic total synthesis of the natural products oleocanthal, geissoschizol, corynantheidol, dihydrocorynantheol, protoemetinol, and 3-epi-protoemetinol from a single synthetic intermediate. Also described are efforts to produce an optically pure supply of the common synthetic intermediate of the above described natural products. The work described herein represents the first steps toward the development of a general strategy capable of synthesizing several structurally diverse members of the family of compounds derived from secologanin.
Open Access
A selection of nitric oxide-releasing materials incorporating S-nitrosothiols
(Colorado State University. Libraries, 2017) Lutzke, Alec, author; Reynolds, Melissa, advisor; Henry, Charles, committee member; Kennan, Alan, committee member; Kipper, Matthew, committee member
Nitric oxide (NO) is a diatomic radical that occurs as a crucial component of mammalian biochemistry. As a signaling molecule, NO participates in the regulation of vascular tone and maintains the natural antithrombotic function of the healthy endothelium. Furthermore, NO is produced by phagocytes as part of the immune response, and exhibits both antimicrobial and wound-healing effects. In combination, these beneficial properties have led to the use of exogenous NO as a multifunctional therapeutic agent. However, the comparatively short half-life of NO under physiological conditions often renders systemic administration infeasible. This limitation is addressed by the use of NO-releasing polymeric materials, which permit the localized delivery of NO directly at the intended site of action. Such polymers have been utilized in the development of antithrombotic or antibacterial materials for biointerfacial applications, including tissue engineering and the fabrication of medical devices. NO release from polymers has most frequently been achieved through the incorporation of functional groups that are susceptible to NO-forming chemical decomposition in response to appropriate environmental stimuli. While numerous synthetic sources of NO are known, the S-nitrosothiol (RSNO) functional group occurs naturally in the form of S-nitrosocysteine residues in both proteins and small molecule species such as S-nitrosoglutathione. RSNOs are synthesized directly from thiol precursors, and their NO-forming decay has generally been established to produce the corresponding disulfide as a relatively benign organic byproduct. For these reasons, RSNOs have been conscripted as practical NO donors within a physiological environment. This dissertation describes the synthesis and characterization of RSNO-based NO-releasing polymers derived from the polysaccharides chitin and chitosan, as well as the development of amino acid ester-based NO-releasing biodegradable poly(organophosphazenes) (POPs). The broad use of chitin and chitosan in the development of materials for tissue engineering and wound treatment results in a significant overlap with the therapeutic properties of NO. NO-releasing derivatives of chitin and chitosan were prepared through partial substitution of the carbohydrate hydroxyl groups with the symmetrical dithiols 1,2-ethanedithiol, 1,3-propanedithiol, and 1,6-hexanedithiol, followed by S-nitrosation. Similarly, thiol-bearing polyphosphazenes were synthesized and used to produce NO-releasing variants. Polyphosphazenes are a unique polymer class possessing an inorganic backbone composed of alternating phosphorus and nitrogen atoms, and hydrolytically-sensitive POP derivatives with organic substituents have been prepared with distinctive physical and chemical properties. Although POPs have been evaluated as biomaterials, their potential as NO release platforms has not been previous explored. This work describes the development of NO-releasing biodegradable POPs derived from both the ethyl ester of L-cysteine and the 3-mercapto-3-methylbutyl ester of glycine. The NO release properties of all polymers were evaluated at physiological temperature and pH, and the results suggested potential suitability in future biomaterials applications.
Open Access
A study of magnetostructural parameters related to spin crossover and single molecule magnetism
(Colorado State University. Libraries, 2013) Fiedler, Stephanie R., author; Shores, Matthew P., advisor; Kennan, Alan J., committee member; Anderson, Oren P., committee member; Crans, Debbie C., committee member; Patton, Carl E., committee member
Herein are described several methods to probe transition metal complexes that were designed by systematic structural modifications to allow for comparison of the resultant magnetic properties. In Chapter 1, a brief introduction is presented to introduce the broader goal of our research: controlling spin on the synthetic level. The introduction provides background regarding spin crossover and single molecule magnetism as well as some previous research to put our projects in context relative to endeavors by other researchers. In Chapter 2, heteroleptic complexes of the form [Fe(H2bip)2(pizR)]Br2 and [Fe(H2bip)2(pizR)](BPh4)2 are described, which have the opportunity to chelate an anion via hydrogen bonding to the H2bip ligand. The third ligand, pizR, is varied between two ligands that we predict will have similar ligand field strengths: pizH and pizMe. Because pizH has an additional hydrogen-bonding site, while pizMe does not, we selected these ligands in order to understand the effect of hydrogen bonding on the anion-binding/spin-state switching event independent from ligand field strength. From these studies, the pizH anion hydrogen bond is observed in crystallographic studies, but does not affect the anion-binding or spin-state switching properties in solution. In Chapter 3, we further investigate the geometry of the pizR ligand in Fe(II) complexes. What began as attempts to study hydrogen bonding in solution revealed unexpected structural distortions of the ligand that are correlated to the spin state of the complexes. The R-substituted nitrogen atom on the imidazoline moiety of the pizR ligand switches between a planar geometry, which is observed for high-spin species, and a pyramidalized geometry, which is observed for low-spin species. We reason that this occurs as a result of the weak-field, non-pizR ligands that influence the ligand field in the high-spin species. Chapters 4 and 5 delve deeper into understanding the relationship between structural parameters and magnetic properties in complexes with non-covalent interactions. In Chapter 4, a series of complexes with metallophilic Pt-Pt interactions show antiferromagnetic magnetic coupling of non-bonded transition metals through a Pt-Pt bond. By comparing complexes with Pt-Pt interactions to those without Pt-Pt interactions, we are able to determine that the Pt-Pt bond is a unique superexchange pathway for the transition metal coupling. Off-set complexes, exhibiting two Pt S interactions instead of one Pt-Pt interaction, do not show evidence of magnetic coupling between transition metals. Furthermore, by comparing magnetic properties of complexes where the apical ligand varies, we determine that the presence or absence of intermolecular interactions is largely independent from the strength of coupling through the Pt-Pt bond. In Chapter 5, an asymmetric trinuclear manganese complex with unique magnetic exchange properties and two high-spin square planar complexes of iron and cobalt, are investigated. The trinuclear manganese complex consists of a central octahedral Mn(II) ion that is coupled antiferromagnetically to another octahedral Mn(II) ion and ferromagnetically to a terminal tetrahedral Mn(II) ion. The different coupling is rationalized as a result of the change in geometry, which affects the orbital overlap that is predicted for each pair of ions. The high-spin square-planar Fe(II) and Co(II) complexes illustrate an unusual pairing of spin-state with square-planar geometry. Moreover, the Fe(II) complex exhibits signs of easy-axis molecular anisotropy and slow-relaxation of magnetization, albeit in the presence of a magnetic field. Lastly, in Chapter 6, we investigate a trinuclear Fe(III) complex bridged by a triethynylmesitylene ligand. The magnetic properties of the complex are compared to a previous Fe(III) complex bridged by a triethynylbenzene ligand. Steric interactions between the aromatic core of the ethynylmesitylene ligand and the auxiliary dimethylphosphinoethane ligands on Fe(III) are predicted to engender a ligand conformation to promote strong orbital overlap. Magnetic susceptibility data for the two complexes both exhibit ferromagnetic coupling between metal centers as expected. Further studies are necessary to confirm the observed behavior, but the new triethynylmesitylene complex appears to have slightly stronger coupling than the previous triethynylbenzene complex.
Open Access
A study of structural organizations in amorphous oxide thin films for low mechanical loss mirror coatings in interferometric gravitational wave detectors
(Colorado State University. Libraries, 2021) Yang, Le, author; Menoni, Carmen S., advisor; Chung, Jean K., committee member; Szamel, Grzegorz, committee member; Bradley, Mark R., committee member
Amorphous thin films prepared from vapor deposition are nonequilibrium solids with structures dependent on their physical parameters, such as composition, and method of preparation. The macroscopic properties of an amorphous material are fundamentally connected to the atomic configuration at the microscopic level. Two-level systems, conceptualized as two adjacent potential wells in the potential energy landscape, are due to intrinsic atomic disorder in amorphous materials. When coupled with an elastic field, the configuration change between the two wells creates a dissipation of mechanical energy that manifests itself as the mechanical loss angle. The mechanical loss of the thin films composing the high reflectivity mirror coating has become the dominant noise source limiting further performance improvements for the next generation gravitational wave detectors. The study presented here comprises investigations of key structural organizations that correlate with the room temperature mechanical loss in vapor-deposited amorphous oxide thin films. In theory, manipulations of substrate temperature or use of assist ion bombardment that transfers energy to the film surface are capable of introducing structural changes during the highly dynamic transition of sputtered particles from the vapor to the solids phase. Tuning the composition by doping or nanolayering is also effective at altering the atomic structure of the amorphous materials. Herein, we discuss in detail the findings from each work. In work on Ta2O5, the effects of low energy assist ion bombardment on the mechanical loss of amorphous thin films are presented. Bombarding ions of Ar+, Xe+, and O2+ of different energy and different dose are directed to the thin films' surface during growth. Negligible influence is found from the assist ion bombardment on the atomic structure and mechanical loss of the Ta2O5 thin films. Based on an analysis of surface diffusivity, it is suggested that the dominant deposition of Ta2O2 cluster might be responsible for the unaltered mechanical loss for Ta2O5 thin films. The parameter space explored within the experimental setup is not capable of affecting the atomic arrangements. It has been proposed that modifiers such as dopants and nanolayers incorporated into the Ta2O5 matrix alter the atomic network in a beneficial way. Two systems of SiO2/Ta2O5 and TiO2/Ta2O5 in both mixture and nanolaminate forms are investigated. For the nanolaminates, it is demonstrated that thermal treatment results in a morphological change that involves layer breakup and mixture formation at the interface in the TiO2/Ta2O5 nanolaminate. Similarly, a stable mixed phase is only formed in the TiO2/Ta2O5 mixture after annealing. The formation of a mixture is suggested to be the key to the lower mechanical loss of the TiO2/Ta2O5 in contrast to the SiO2/Ta2O5 system. The two-level systems are essentially modified when the system con- figures itself in a thermodynamically more stable state. Combined with results from the atomic modeling using molecular dynamics of TiO2/Ta2O5, it is then proposed that the medium-range order in these oxides is key to lowering the room temperature mechanical loss. A direct evaluation of the modifications at the medium-range order is obtained from work on amorphous GeO2 thin films. GeO2 with a maximized degree of medium-range order is investigated with elevated temperature deposition. It is demonstrated that the medium-range or- der of amorphous GeO2, characterized by GeO4 tetrahedra connected in rings of various sizes, evolves into a more ordered configuration at elevated temperatures. A systematic decrease in mechanical loss is associated with the increase in medium-range order for the GeO2 thin films. We conclusively show that an improved packing at medium range is linked to the low mechanical loss for the amorphous oxide thin films. Furthermore, engineering of GeO2 to achieve a high refractive index is carried out by the incorporation of TiO2. We identified the optimal cation concentration Ti/(Ge+Ti) around 44%, which provides both low mechanical loss and low absorption loss for the mixture to be used in the multilayer stack. The designed high reflector multilayer is calculated to have the Brownian thermal noise near the target for next-generation Advanced LIGO. In combination, the results described in this dissertation have identified key structural organizations that affect the room temperature mechanical loss of amorphous oxide thin films. The evolution in the connecting rings of metal-centered oxygen polyhedra in these thin films is essential to altering the medium-range order in the atomic network. Such modifications could be achieved with the formation of a thermodynamically more stable phase, elevated deposition temperature, or post-deposition thermal treatment. Future work to identify the microscopic origin of low-temperature mechanical loss is envisioned for a thorough understanding of the two-level systems present in the amorphous oxides.
Open Access
Accessing a new molecular scaffold for Fe(II) spin state switching through first coordination changes
(Colorado State University. Libraries, 2021) Livesay, Brooke N., author; Shores, Matthew P, advisor; Rappé, Anthony K., committee member; Van Orden, Alan, committee member; Ross, Kathryn A., committee member
Presented in this dissertation are the syntheses and characterizations of iron spin state switching complexes. The magnetic properties are extremely sensitive to environmental changes such as ligand field, coordination environment, and crystal packing. These studies focus on developing a better understanding of how the magnetic properties of iron complexes can be controlled by environmental modifications. The first chapter provides a detailed introduction to spin state switching. The chapter includes the origins of the phenomenon and background into previous efforts to modify the spin switching event. This chapter highlights the challenges of designing a spin state switching complex and the different pathways used to induce spin switching events in the solid state and solution phase. Chapter 2 describes the procedures used to collect solution magnetic data. This chapter details the advantages of collecting solution data using a MPMS instrument compared to the Evans' (1H NMR) Method. The standard operating procedures for the method using a MPMS instrument are described for future researchers. Examples of solution magnetic data collected by both methods are described and compared. Chapter 3 discusses the challenges that were encountered during the synthesis of an iron(II) complex. The synthesis stopped producing the desired product after it was successful for several months. Investigations into the reproducibility, synthetic methods, and purification steps were performed to understand why the original synthetic procedure stopped working. This chapter describes how commercially-available starting materials can differ between lot numbers and manufacturers and how these small differences can lead to significant changes in the purity of the final product. Chapter 4 discusses the impact of speciation on the spin state switching properties of the neutral iron(II) compound synthesized in Chapter 3. Analysis in the solid state indicates the iron(II) complex is in the high spin state at all temperatures. When this compound is dissolved in strongly coordinating solvents the bound anions are replaced by the solvent resulting in a high spin species when the solvent is oxygen-donating and low spin species when the solvent is nitrogen-donating. In non-coordinating solvents the iron(II) complex loses one of the bound anions but remains high spin. However, in moderately coordinating solvents like acetone, the iron(II) loses the bound anions upon decreasing the temperature, resulting in a coordination induced spin state switching event. These studies highlight the sensitivity of solvent choice on the solution magnetic properties of iron(II) compounds. Chapter 5 discusses the thought process used to design the synthetic procedure for the post-synthetic modification of an iron(II) compound. The azide alkyne cycloaddition reaction was tested with several catalysts and deprotecting agents. Thoughtful consideration was taken to avoid the transmetallation reaction between the cycloaddition catalyst and the iron(II) compound. The successful reaction conditions for the post synthetic modification were found and resulted in the formation of the desired iron(II) triazole compound. Additional iron(II) triazole complex salts synthesized following the method described in Chapter 5 are described and characterized in Chapter 6. Electron-donating, electron-withdrawing, and oxidation-sensitive substituents are included on the iron(II) triazole ligand to show the scope of the post synthetic modification reaction and allow for investigation into how substituents effect the magnetic properties of the resulting compounds. Variable temperature solid state magnetic characterization indicates the resulting iron(II) compounds show a variety of magnetic behaviors. However, analysis of the crystallographic data and comparison to related previously published iron(II) triazole compounds indicate the differences in the magnetic properties are due to the solid state crystal packing effects. In Chapter 7 the solution magnetic properties of the iron(II) triazole compounds described in Chapter 6 are discussed. Removing the crystal packing effects by characterizing the compounds in solution allows for discovery of a relationship between the substituent properties and the magnetic behavior of the resulting compounds. The compounds were characterized in d4-CD4OD by Evans' 1H NMR method and show a thermal spin state switching event. However, no relationship between the Hammett parameter of the substituents and the spin state properties was observed. Chapter 8 summarizes the investigation of solvent induced spin state switching and post-synthetic modification. Additionally, I discuss some future work that would expand on the studies presented in this dissertation.
Open Access
Accessing molecular structure and dynamics of photoelectrochemical systems with nonlinear optical spectroscopy
(Colorado State University. Libraries, 2022) Farah, Yusef Rodney, author; Krummel, Amber T., advisor; Szamel, Grzegorz, committee member; Barisas, B. George, committee member; Bartels, Randy, committee member
Photoelectrochemical cells (PEC) are a class of solar energy device that have a variety of applications and can be used to directly generate electricity or convert the sun's energy in the form of chemical bonds through photosynthetic processes. The first PEC dates to Becquerel's discovery of the photovoltaic effect in 1839; and, after nearly 200 years of its first creation, the PEC is constantly evolving with the discovery of new fabrication techniques and materials. Sunlight harvesting materials are used in PECs to capture the sun's radiation and drive electron transfer and photocatalytic reactions. Understanding the photophysical properties of the materials used within PEC chemical systems informs on the development of high-performance, low-cost, and sustainable solar energy devices needed to address current global climate challenges and meet societal energy demands. Chemical systems in PEC architectures are nontrivial and often rely on several components working harmoniously in tandem with one another to stimulate photovoltaic or photocatalytic processes. Dye-sensitized solar cells (DSSCs) are a type of photovoltaic PEC that use molecular chromophores to absorb light, transfer electrons to a semiconductor, and accept electrons from an electrolyte. Local environmental structure of the chromophore can either promote or hinder these electron transfer events within a device. To this end, investigating the molecular structure of the chromophore, including the parameters that influence the structure, is necessary for fabricating DSSCs with optimal efficiency. The work presented in this dissertation utilizes the nonlinear optical spectroscopic technique of heterodyne-detected vibrational sum frequency generation (HD-VSFG) to investigate the interfacial structure of N3-dye, a popular chromophore used within DSSC devices. It is discovered that the interfacial structure of N3 is influenced by the substrate, pH conditions upon deposition to the substrate, and by the presence of an electrolyte. Additionally, the work presented herein investigates exciton dynamics of monolayer MoS2 photoanodes within an operational PEC. Monolayer transition metal dichalcogenides (TMDs), such MoS2, are two-dimensional semiconducting materials with fascinating photophysical properties. Only recently have monolayer TMDs been investigated for their integration within optoelectronic devices, such as PECs. By utilizing ultrafast transient absorption (TA) spectroscopy, unique exciton properties of the MoS2 photoanode are identified within operational conditions. Photocurrent generation via ultrafast hot carrier extraction is discovered, challenging the preconceived notions of the Shockley-Queisser limit; further, we explore the dynamic control of the exciton energy by tuning an external voltage bias to the PEC. PEC chemical environments are ubiquitous and the photophysical properties are dependent on many underlying parameters. Set forth in this dissertation is the foundation for applying the nonlinear optical techniques of HD-VSFG and TA across a variety of chemical systems pertaining to PECs and assessing data within an established theoretical framework to elucidate molecular structure and dynamics.
Open Access
Adsorptive separations of phytocannabinoids and pesticides in the liquid phase
(Colorado State University. Libraries, 2022) Cuchiaro, Jamie H., author; Reynolds, Melissa, advisor; Farmer, Delphine, committee member; Chung, Jean, committee member; Reardon, Ken, committee member
To view the abstract, please see the full text of the document.
Open Access
Advancements in organocatalyzed atom transfer radical polymerization by investigation of key mechanistic steps
(Colorado State University. Libraries, 2022) Corbin, Daniel Andreas, author; Miyake, Garret, advisor; Finke, Richard, committee member; Rappé, Anthony, committee member; Kipper, Matt, committee member
Organocatalyzed atom transfer radical polymerization (O-ATRP) is a controlled radical polymerization method employing organic photoredox catalysts to mediate the synthesis of well-defined polymers. The success of this method derives from its reversible-deactivation mechanism, where polymers are activated by reduction of a chain-end C-Br bond to generate a reactive radical for chain growth, followed by deactivation of the polymer by reinstallation of the dormant bromide chain-end group. As a result, the polymer chain can be grown by reaction of the polymer radical with alkene-based monomers, but undesirable termination and side reactions can be suppressed by minimization of the radical concentration through deactivation. In this work, key mechanistic steps of O-ATRP are investigated to understand the fundamental limitations of this method and improve upon them. When N,N-diaryl dihydrophenazines were investigated, side reactions were identified in which alkyl radicals add to the phenazine core, leading to new core-substituted PC derivatives with non-equivalent catalytic properties. Employing these core-substituted PCs in O-ATRP showed these side reactions can be eliminated to improve polymerization control. In addition, the deactivation step of O-ATRP and related intermediates were studied, which revealed new side reactions that can limit polymerization efficiency as well as influences on the rate of deactivation. Finally, methods to exert control over the deactivation process were developed as a means of improving polymerization outcomes in challenging systems. For example, the intermediate responsible for deactivation was isolated and added to a polymerization to increase the rate of deactivation and limit side reactions in O-ATRP. Alternatively, a similar outcome could be achieved through in-situ electrolysis to increase the concentration of the desired intermediate during the polymerization. Ultimately, this work has yielded insight into important mechanistic processes in O-ATRP that will continue to benefit the development of this method.
Embargo
Advancements in the chemical recyclability of acrylic polymers through investigation of monomer design
(Colorado State University. Libraries, 2024) Gilsdorf, Reid Anthony, author; Chen, Eugene, advisor; Miyake, Garret, committee member; Shores, Matthew, committee member; Herrera-Alonso, Margarita, committee member
Depolymerization is a key avenue of state-of-the-art recycling of polymeric materials. Although many polymers have been investigated for their ability to depolymerize, a subset of polymers has been widely left out of the conversation, polyolefins, or polymers containing C-C bonds in the polymer main-chain. Acrylic polymers are an important class of polyolefins used throughout the world in a variety of applications. One of the key drawbacks of the polymer, however, is their unfavorable depolymerization conditions, requiring high temperatures in expensive reactors. Although much work has been performed on the depolymerization of the most widely used acrylic polymer, poly(methyl methacrylate) (PMMA), there have been few reports on trying to improve upon the recycling methods, such as decreasing depolymerization temperature or gaining control over the depolymerization mechanism. In this work, key mechanistic steps of acrylic polymer depolymerization are investigated to gain fundamental understanding on the limitations faced during depolymerization and try to improve upon them. When poly(α-methylene-γ-butyrolactone) (PMBL) and poly(α-methylene-γ-methyl-γ-butyrolactone) (PMMBL) were investigated, the suppression of side reactions that occurred with PMMA depolymerization were identified, attributed to the pendant lactone tethering radical species together. Employing this tethering effect, the design of new polymers with pendant lactones and lower equilibrium polymerization temperatures (ceiling temperature or TC), was carried out, overall decreasing depolymerization temperatures and improving polymer recyclability. Finally, these new polymers were incorporated into the design of copolymers with PMMA and PMMBL in order to exploit the new polymers' depolymerizability without hindering thermomechanical properties. Overall, this work has shed light onto the importance of polyolefin design in, not just thermomechanical properties, but also polymerization and depolymerization behavior which will benefit the continued development of recyclable-by-design polymers.
Open Access
Advancing point-of-need bacteria detection using microfluidic paper-based analytical devices
(Colorado State University. Libraries, 2018) Boehle, Katherine Elizabeth, author; Henry, Charles S., advisor; Krummel, Amber T., committee member; Geiss, Brian J., committee member; Ackerson, Christopher J., committee member
Bacteria are responsible for more hospitalizations and deaths than any other foodborne contaminant, making the detection of these pathogens of utmost importance. To further complicate bacteria detection, the overuse of antibiotics and genetic plasticity of bacteria has caused antimicrobial resistant (AMR) bacteria to become a more prevalent issue that threatens to be the number one cause of death worldwide by 2050 unless significant innovations are made. Although bacteria detection in the field is ideal, the current gold standards for detection require trained personnel and a central laboratory. The primary work in this dissertation acts to improve upon current bacteria detection methods by designing, developing, and optimizing inexpensive user-friendly tests that detect bacteria at the point-of-need without trained personnel or expensive equipment. These goals are accomplished using microfluidic paper-based analytical devices (μPADs), a growing field for point-of-need detection that have been used for a variety of analytes and applications. Using paper as a platform has allowed for the simple development of user-friendly devices because of their easily designed and modifiable material that typically costs <$0.01 USD per device and allows for multiple tests to be completed from one sample addition. Devices that will be described include colorimetric spot tests that detect common fecal indicator bacteria (FIB) species Escherichia coli and Enterococci spp. based on enzymes that are naturally produced by the bacteria. Utilizing these enzymes, a test was developed that turns from clear to yellow as an indication of live bacteria. These tests were successfully used in the detection of bacteria in food and water samples to demonstrate its efficacy in food safety applications. To improve specificity and sensitivity of bacteria detection, a second spot test was developed that utilizes immunomagnetic separation (IMS) and an enzymatic sandwich immunoassay in the detection of another common foodborne pathogen, Salmonella typhimurium. This assay was developed specifically for detecting pathogens in complex matrices, such as one of the most common causes of pathogen contamination: animal feces. Because AMR bacteria are becoming a more prevalent problem, devices were developed to specifically detect bacteria resistant to β-lactam antibiotics, the most common case of antimicrobial resistance observed in bacteria. The first generation of devices were developed to detect β-lactamase activity, an enzyme that facilitates resistance against β-lactam antibiotics. These devices were successful in detecting AMR in different species of bacteria isolated from environmental samples, and in the detection of AMR in sewage water. The second generation of devices enables detection of resistance against specific antibiotics through hydrolysis of the antibiotic and detecting a change in pH. Although not yet demonstrated, these devices will eventually be used to determine if bacteria are resistant against specific classes of β-lactam antibiotics, including a commonly used class of last resort antibiotics, carbapenems. Beyond bacteria detection, this dissertation also explores developing a field-ready device to identify falsified and substandard antibiotics. Because antibiotics are most commonly counterfeited in resource-limited settings, it is imperative to develop user-friendly point-of-need devices that can quantify the amount of active pharmaceutical ingredient in antibiotics. This was accomplished using enzyme competition, a method that had not been demonstrated paper-based devices. Finally, all devices that have been developed and optimized in this dissertation utilized colorimetric detection. While a user-friendly and easily implemented method of detection, it does suffer from drawbacks such as sensitivity and user subjectivity when using the devices. To eliminate subjectivity, a portable system using a Raspberry Pi computer and 3D-printed light box and device holder have been optimized. Although the system has been demonstrated by automatically analyzing images and calculating Michaelis-Menten enzyme kinetic values, this system has limitless possibilities in automatically analyzing colorimetric paper-based devices for truly objective colorimetric readouts and quantitative infield detection of pathogens or other analytes.
Embargo
Advancing the utility of organic superbases in synthetic methodology
(Colorado State University. Libraries, 2023) Sujansky, Stephen J., author; Bandar, Jeffrey, advisor; Miyake, Garret, committee member; Sambur, Justin, committee member; Cohen, Robert, committee member
Deprotonation is one of the most fundamental and important modes of molecular activation, making Brønsted bases a critical part of a synthetic chemist's toolbox. An exceptional class of Brønsted bases are organic superbases, which are finding increased use in modern synthetic methods due to their unique properties. This thesis describes the use of these unique properties to advance the synthetic utility of superbases in two ways; 1) improving superbase- catalyzed alkene hydrofunctionalization reactions; and 2) developing air-stable and convenient organic superbase prereagents. Chapter One describes organic superbases in detail to provide background and context for Chapters Two and Three. Within Chapter One, various classes of superbases are presented, as well as their unique properties, syntheses, and example applications. Finally, the limitations and challenges associated with the use of superbases are discussed. Chapter Two describes the Bandar Group's superbase-catalyzed alkene hydrofunctionalization methodology. Within this chapter mechanistic studies as well as computational modeling, done as part of a collaboration with the Paton Group, are presented. These mechanistic studies provided insight into the factors controlling the reaction equilibrium. This insight was then used to logically address the limitations associated with the original conditions reported by the Bandar Group in 2018. The results of this work help to improve reaction efficiency and to expanded substrate scope. This understanding also led to the development of a catalytic anti-Markovnikov aryl alkene hydration method that allows convenient access to β-aryl alcohols. Chapter Three describes the development of air-stable organic superbase precatalysts and prereagents. Superbase salts that decarboxylate were developed as a first strategy method to generate the neutral superbase in solution. This initial salt system then led to the discovery of stable superbase carboxylate salts that react with and open epoxide additives in situ to neutralize the superbase conjugate acid. This ring strain release strategy is shown to be effective at promoting a range of reactions including Michael-type addition, ester amidation, deoxyfluorination, SNAr and Pd-catalyzed cross coupling reactions. These superbase precatalysts and prereagents provide a means to access the unique properties of organic superbases from air-stable and easy-to-handle salts. Overall, Chapters Two and Three represent significant progress in advancing the utility of organic superbases in synthetic methodology. My work in Chapter Two, along with the Bandar's and Paton Group's efforts, meaningfully expanded the scope and usefulness of superbase- catalyzed alcohol addition reactions. Our new mechanistic understanding proved to be fundamental to a range of addition reactions and pushed the boundary of possible nucleophilic addition reactions. My efforts in Chapter Three, along with Garrett's significant contributions, have made organic superbase much more convenient to use, synthesize and store. This greater convenience and potentially lower cost can be expected to improve access to superbase chemistry and serve as the foundation for future discoveries. Additionally, the ability to control the concentration of superbase in solution will have many benefits in expanding substrate scopes and modulating reaction profiles where a strong base is required but is also detrimental to the overall process.
Open Access
Affinity maturation and characterization of novel binders to the HIV-1 TAR element based on the U1A RNA recognition motif
(Colorado State University. Libraries, 2018) Crawford, David W., author; McNaughton, Brian, advisor; Ackerson, Christopher, committee member; Ross, Eric, committee member; Bedinger, Patricia, committee member
The increased understanding of the importance of RNA, both as a carrier of information and as a functional molecule, has led to a greater demand for the ability to target specific RNAs, but the limited chemical diversity of RNA makes this challenging. This thesis documents the use of yeast display to perform affinity maturation for the ability of a protein to bind the TAR element of HIV-1, which is a desirable therapeutic target due to its prominent role in the HIV-1 infection cycle. To accomplish this, we used a "semi-design" strategy—repurposing a natural RNA bind- ing protein to bind a different target—by creating a library based on important binding regions (especially the β2β3 loop) of the U1A RRM. Following selection for TAR binding, a strong consensus sequence in the β2β3 loop emerged. The affinity of certain library members for TAR was measured by ELISA and SPR, and it was determined that the best binder (TBP 6.7) had remarkable affinity (KD = ~500 pM). This TAR binding protein also proved capable of disrupting the Tat–TAR interaction (necessary for HIV-1 replication) both in vitro and in the context of extracellular transcription. Through collaboration, we were able to obtain a co-crystal structure of TBP 6.7 and TAR. This crystal structure showed that the overall structure of TBP 6.7 was largely unchanged from that of U1A, thereby validating our semi-design strategy. We also found that the β2β3 loop played a disproportionately large role in the binding interaction (~2⁄3 of the buried surface area). The importance of this region inspired the creation and characterization of peptide derivatives of the TBP 6.7 β2β3 loop. These β2β3 loop derived peptides maintain affinity for TAR RNA (KD = ~1.8 μM), and can disrupt Tat/TAR-dependent transcription. Ultimately, the project has yielded the most avid known binders of TAR RNA, a potential novel platform of TAR binding peptides, and a crystal structure which will hopefully inform future targeting efforts.
Open Access
Air quality implications from oxidation of anthropogenic and biogenic precursors in the troposphere
(Colorado State University. Libraries, 2019) Link, Michael F., author; Farmer, Delphine, advisor; Fisher, Ellen R., committee member; Neilson, James R., committee member; Jathar, Shantanu H., committee member; Ravishankara, Akkihebbal R., committee member
Oxidation chemistry in the troposphere drives the formation of air pollutants, harmful to human health and the natural world. Emissions from both anthropogenic and biogenic sources control the ways in which air pollution is formed and thus understanding the chemistry of the oxidation of these emissions enhances our ability to predict how air quality evolves in the future. Experiments simulating tropospheric oxidation chemistry on anthropogenic point sources show that identifying unique chemical processes resulting in air pollution allow for a greater specificity in how to pursue strategies for pollution mitigation policy with regional and hemispheric implications. This thesis focuses on the implementation of advancements in instrumentation and experimental techniques to understand how tropospheric oxidation of anthropogenic and biogenic precursors can produce air pollution. First, we subject vehicle exhaust to simulated tropospheric oxidation and quantify the formation of particulate matter and a toxic gas, isocyanic acid. We estimate how important oxidation of vehicle emissions are for these atmospheric pollutants for the South Coast Air Basin of California and the Seoul Metropolitan Region. Second, we investigate the propensity for isoprene to produce formic and acetic acid in laboratory oxidation experiments. We find that isoprene is likely a major source of formic acid in biogenically-influenced environments, however the exact mechanisms for formation remain unclear. Lastly, we use chemical ionization mass spectrometer measurements to quantify the fraction of oxidized carbon allocated to gas-phase organic acids from isoprene oxidation in laboratory experiments. Through comparison with field measurements from a forest in Alabama to a forest in Colorado we determine high levels of isoprene in Alabama are responsible for high levels of organic acids compared to Colorado. We also observe that influences of anthropogenic NOₓ suppress the formation of gas-phase organic acids suggesting as NOₓ levels decrease throughout the US in the future organic acids produced from oxidation from isoprene are likely to increase.
Open Access
Allostery of the flavivirus NS3 helicase and bacterial IGPS studied with molecular dynamics simulations
(Colorado State University. Libraries, 2020) Davidson, Russell Bruce, author; McCullagh, Martin, advisor; Bernstein, Elliot, committee member; Barisas, George, committee member; Geiss, Brian, committee member
Allostery is a biochemical phenomenon where the binding of a molecule at one site in a biological macromolecule (e.g. a protein) results in a perturbation of activity or function at another distinct active site in the macromolecule's structure. Allosteric mechanisms are seen throughout biology and play important functions during cell signaling, enzyme activation, and metabolism regulation as well as genome transcription and replication processes. Biochemical studies have identified allosteric effects for numerous proteins, yet our understanding of the molecular mechanisms underlying allostery is still lacking. Molecular-level insights obtained from all-atom molecular dynamics simulations can drive our understanding and further experimentation on the allosteric mechanisms at play in a protein. This dissertation reports three such studies of allostery using molecular dynamics simulations in conjunction with other methods. Specifically, the first chapter introduces allostery and how computational simulation of proteins can provide insight into the mechanisms of allosteric enzymes. The second and third chapters are foundational studies of the flavivirus non-structural 3 (NS3) helicase. This enzyme hydrolyzes nucleoside triphosphate molecules to power the translocation of the enzyme along single-stranded RNA as well as the unwinding of double-stranded RNA; both the hydrolysis and helicase functions (translocation and unwinding) have allosteric mechanisms where the hydrolysis active site's ligand affects the protein-RNA interactions and bound RNA enhances the hydrolysis activity. Specifically, a bound RNA oligomer is seen to affect the behavior and positioning of waters within the hydrolysis active site, which is hypothesized to originate, in part, from the RNA-dependent conformational states of the RNA-binding loop. Additionally, the substrate states of the NTP hydrolysis reaction cycle are seen to affect protein-RNA interactions, which is hypothesized to drive unidirectional translocation of the enzyme along the RNA polymer. Finally, chapter four introduces a novel method to study the biophysical coupling between two active sites in a protein. The short-ranged residue-residue interactions within the protein's three dimensional structure are used to identify paths that connect the two active sites. This method is used to highlight the paths and residue-residue interactions that are important to the allosteric enhancement observed for the Thermatoga maritima imidazole glycerol phosphate synthase (IGPS) protein. Results from this new quantitative analysis have provided novel insights into the allosteric paths of IGPS. For both the NS3 and IGPS proteins, results presented in this dissertation have highlighted structural regions that may be targeted for small-molecule inhibition or mutagenesis studies. Towards this end, the future studies of both allosteric proteins as well as broader impacts of the presented research are discussed in the final chapter.
Open Access
An investigation of the effect of surface released nitric oxide on fibrinogen adsorption
(Colorado State University. Libraries, 2014) Lantvit, Sarah Marie, author; Reynolds, Melissa, advisor; Borch, Thomas, committee member; Fisher, Ellen, committee member; Kennan, Alan, committee member; Popat, Ketul, committee member
The search for improved biomaterials is a continually ongoing effort to prevent the failure of medical devices due to blood clotting. Each group of researchers has their own set of methods to create the ideal material for biological systems. In the pursuit of materials to prevent blood clot formation, these attempts have been focused on alterations in surface properties, pre-adsorption of proteins, and release of drugs. In this work I took a high-throughput approach to the prevention of device failure by investigating a model material system. Starting with a nitric oxide (NO) releasing material, a sample preparation method was developed to ensure that surface properties could be compared to a non-NO releasing control. With this material, the effect of the NO release on fibrinogen adsorption to these surfaces could be isolated. Fibrinogen is instrumental in the formation of blood clots. Determining the effect that NO has on this protein will help determine why NO has been previously found to prevent clotting in blood-contacting systems. Once the model system was developed, further investigation into changes in the fibrinogen resulting from its interaction with the released NO could be undertaken. A full investigation was completed on control non-NO releasing, low NO flux, and high NO flux materials. A qualitative assessment of the fibrinogen adsorption shows that the high NO releasing material exhibits significantly higher fibrinogen adsorption compared to both the control and low NO flux materials. Quantitative assessment of fibrinogen adsorption was attempted through a variety of methods, which indicate that conformational changes are happening upon adsorption of fibrinogen to all materials. To this end, FTIR spectra from the adsorbed fibrinogen and native fibrinogen were compared to elucidate changes in the protein's conformation. Control and low NO flux materials had too little protein to gain insight into these changes. For the high NO flux material, the fibrinogen had a significant decrease in α-helices and an increase in random chains compared to native fibrinogen. To begin understanding the effect that these changes will have on blood clot formation, these materials were further analyzed for platelet adhesion. A comparison of the control, low NO flux, and high NO flux materials with and without fibrinogen adsorbed to the material surface shows that the fibrinogen has a distinct effect on platelet adhesion and aggregation. The high NO flux materials exhibited less aggregation and full activation of platelets when fibrinogen was adsorbed prior to incubation with platelets than if fibrinogen was not present before incubation. Overall, the effect of NO on fibrinogen adsorption can be seen through these measurements. Nitric oxide release causes an increase in fibrinogen adsorption, as well as protein reorganization. Surprisingly, we see that this adsorbed fibrinogen actually improves the viability of platelets. Further study must be done using whole blood and in vivo measurements to fully understand what effect the adsorbed fibrinogen will have on the device. Despite this we can say that the adsorption of fibrinogen onto these NO releasing materials helps to improve the biocompatibility of this biomaterial due to its bulk adsorption and conformational changes.
Open Access
Analytical spectroscopy method development to study mechanisms of Alzheimer's and tuberculosis diseases
(Colorado State University. Libraries, 2020) Beuning, Cheryle Nicole, author; Crans, Debbie C., advisor; Levinger, Nancy E., committee member; Barisas, George, committee member; Fisher, Ellen R., committee member; Zabel, Mark, committee member
This dissertation covers the analytical method development created to study and enhance the knowledge of two specific disease mechanisms important to Alzheimer's disease and Mycobacterium tuberculosis. There are two parts in this dissertation where Part 1 is entitled Measurement of The Kinetic Rate Constants of Interpeptidic Divalent Transition Metal Ion Exchange in Neurodegenerative Disease. Part 2 is entitled The Electrochemistry of Truncated Menaquinone Electron Transporters with Saturated Isoprene Side Chains Important in Tuberculosis. These diseases appear on the World Health Organization's top 10 leading causes of death worldwide. The amyloid-beta (Aβ) peptides are associated with Alzheimer's disease, where neurodegeneration is caused by the aggregation of the peptide into senile plaques within neuronal synaptic cleft spaces. Alzheimer's disease currently has no cure due to its multi-causative pathology. One disease mechanism is the coordination of divalent metal ions to the peptide. Specifically, Aβ coordinates Cu(II) and Zn(II) ions that can enhance the aggregation of Aβ into plaques. These metal ions are highly regulated within the human body and are usually found bound to peptides and not as free ions. Therefore, the Aβ must sequester the metals from other proteins and peptides. The primary research in this dissertation advances fluorescence method development to measure interpeptidic Cu(II) exchange kinetics to be able to measure this type of disease mechanism. The small peptides GHK (Gly – His – Lys) and DAHK (Asp – Ala – His – Lys) both chelate Cu(II) with nM affinity, have biological relevance as they are motifs found in human blood like Aβ, and chelate Cu(II) with similar nitrogen-rich binding ligands as Aβ. By substituting non-coordinating lysine residues with fluorescent tryptophan, the interpeptidic exchange rates can be measured since tryptophan fluorescence is statically quenched when within 14 angstroms of a paramagnetic bound Cu(II). Thus Cu(II) transfer from Cu(H-1GHW) to either GHK or DAHK can be monitored by recovered GHW fluorescence as the Cu(II) is exchanged and second-order kinetic rate constants were determined. This methodology was then used to monitor the Cu(II) exchange from truncated Cu(Aβ1-16) and Cu(Aβ1-28) complexes to GHW and DAHW, where second-order reaction kinetic rate constants were determined. While in the exchanges between Cu(H-1GHW) with GHK/DAHK the second-order rate constants were on the magnitude of 102 or 101 M-1s-1, respectively, the exchanges from Cu(Aβ) complexes were 2-3 orders of magnitude larger, 104 M-1s-1 (to GHW and DAHW). These differences in rate constant magnitude arise from the fact that the affinity of GHW (KA = 1013 M-1) for Cu(II) is larger than Aβ (KA =1010 M-1). This method development is an important step to an accurate measurement of the interpeptidic exchange between Aβ peptides, including in their fibril and plaque formations. Since senile plaques are found in synaptic cleft spaces with nanometer distances between neurons, a model system was generated to study coordination reactions at the nanoscale. In order to do this, the metal ion would need to be released in a controlled manner. Studies of metal ion burst reactions through the use of photocages can simulate bursts of ions like those seen in the synaptic cleft. Zn(II) is often released in its ionic form within the synapse in its function as a neurotransmitter, so we simulated a burst of Zn(II) ions by using a photocage, [Zn(NTAdeCage)]- which releases Zn(II) when irradiated with light. The photocage was irradiated to release Zn(II) then we followed its reaction progress with an in situ chelator, Zincon, in reverse micelles and in bulk aqueous buffer. The coordination reaction was 1.4 times faster in an aqueous buffer than in reverse micelles, despite the Zn(II) and Zincon being closer in the nanoparticle. These observations suggested that there is an impact on coordination reactivity within a highly heterogeneous environment with a cell-like membrane, which is due to the partitioning of each ligand. We observe that the photocage stays in the water pool of the reverse micelle and the Zincon partitions into the membrane interface. Thus, the coordination reactivity is diminished, likely due to the need for Zn(II) to diffuse to the Zincon, crossing a highly organized Stern layer to encounter the Zincon. Whereas in aqueous buffer, these are free to encounter each other despite being hundreds of nanometers apart. These proof of concept studies are integral to studying initial binding dynamics of metal ions with peptides at the nanoscale present in cells and neuronal synapses. Tuberculosis is a pathogenic bacterium which despite having a curable medication, can be drug-resistant. Menaquinone (MK) analogs with regiospecific partial saturation in their isoprenyl side chain, such as MK-9(II-H2), are found in many types of bacteria, including pathogenic Mycobacterium tuberculosis and function as electron transport lipids cycling between quinone and quinol forms within the electron transport system. While the function of MK is well established, the role of regiospecific partial saturation in the isoprenyl side chain on MK remains unclear and may be related to the redox function. Recently, an enzyme in M. tuberculosis called MenJ was shown to selectively saturate the second isoprene unit of MK-9 to MK-9(II-H2). The knockout expression of this enzyme was shown to be essential to the survival of the bacterium. A series of synthesized truncated MK-n analogs were investigated using a systematic statistical approach to test the effects of regiospecific saturation on the redox potentials. Using principal component analysis on the experimental redox potentials, the effects of saturation of the isoprene tail on the redox potentials were identified. The partial saturation of the second isoprene unit resulted in more positive redox potentials, requiring less energy to reduce the quinone. While full saturation of the isoprene tail resulted in the most negative potentials measured, requiring more energy to reduce the quinone. These observations give insight into why these partially saturated menaquinones are conserved in nature.
Open Access
Anticancer potential of nitric oxide-based therapeutics for pediatric and adult cancers
(Colorado State University. Libraries, 2021) Gordon, Jenna Leigh, author; Reynolds, Melissa, advisor; Henry, Chuck, committee member; Kennan, Alan, committee member; Brown, Mark, committee member
Based on 2015-2017 data, nearly 40% of men and women will be diagnosed with cancer at some point throughout their lives. As a worldwide pandemic, cancer presents a colossal challenge for researchers and clinicians to continually develop and implement new strategies to prevent, diagnose, and treat the many variations of this disease. Currently, treatment protocols are dominated by surgery, chemotherapy, and radiation therapy. Although valuable, these treatments are often ineffective and are limited to specific situations. Surgery is typically useful for early-stage cancer treatment while chemotherapy and radiation therapy are more common for late-stage treatment. Chemotherapy and radiation therapies are subject to drug resistance and all three produce patient side effects. Thus, a persistent need to develop drugs that are more effective, preferential (to neoplastic cells), and accessible remains. This work implements therapeutics that addresses those concerns while demonstrating efficacy within both pediatric and adult cancers. An evaluation of the anticancer potential of nitric oxide (NO) releasing S-nitrosothiol based anticancer therapeutics is presented herein. In the determination of clinical translatability of a drug, it is essential to understand the desired outcome and potential sources of error prior to execution of analyses and the corresponding methodologies and measurements. Thus, an in-depth analysis of indicators for therapeutic efficacy using tumor-derived cell lines and a detailed investigation of the protocol development and potential interferences of three common cellular viability assays is presented prior to the in vitro work detailed in this study. Specifically, this study involves the application of the NO releasing S-Nitrosothiol, S-Nitrosoglutathione (GSNO) in two variations to determine efficacy against pediatric neuroblastomas and adult breast cancers. Initially, two studies explore the application of GSNO in solution to multiple neuroblastoma cell lines of various origins to determine the potential of NO to act as an adjuvant therapeutic in the clinical management of the prevalent pediatric cancer neuroblastoma. These studies highlight the incredible impact of NO on clonogenic capacity as well as remarkable discriminatory characteristics between neoplastic and healthy cells. Further, the insight presented regarding the mechanism of action of NO on neuroblastomas expands the comprehension of NO-based anticancer therapeutics. Excitingly, when the same GSNO preparation is subsequently applied to more common adult breast cancers to determine if therapeutic efficacy is maintained, results display analogous consequences to those mentioned above. The final study in this dissertation will also explore another application of solution-phase GSNO to adult breast malignancies by combining it with a novel SMYD-3 inhibitor, termed Inhibitor-4 (by collaborators). Since Inhibitor-4 has been shown to similarly impact viability, clonogenic capacity, and apoptosis, this combination is expected to reveal a greater impact than each individual treatment. Overall, an analysis of the significance and feasibility of NO-based therapeutics, delivered via GSNO, is explored to determine their potential application in the clinical management of various cancers. Ultimately, this work expands the knowledge of the practicality, mechanism of action, and effectiveness of NO-based anticancer therapeutics in various cancers with a specific focus on its applicability in neuroblastomas, a malignancy where minimal focus has been placed on NO as a treatment option.