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Aliovalent Dopants In Zno Nanocrystals: Synthesis To Electronic Structure, Dongming Zhou Nov 2017

Aliovalent Dopants In Zno Nanocrystals: Synthesis To Electronic Structure, Dongming Zhou

Doctoral Dissertations

Semiconductor nanocrystal doping has stimulated broad interest for many applications including solar energy conversion, nanospintronics, and phosphors or optical labels. The study of the chemistry and physics of doped colloidal semiconductor nanocrystals has been dominated in the literature by isovalent dopants such as Mn2+ and Co2+ ions in II-VI semiconductors, in which the dopant oxidation state is the same as the cation ions. Until recently, aliovalent dopants has received much attention due to the plasmonic properties. Aliovalent is when the oxidation states of the dopant in the lattice differs from the cation ions. In the plasmonic semiconductor nanocrystals, …


Characterization Of Highly Heterogeneous Heparin-Protein Complexes Using Novel Mass Spectrometry-Based Approaches, Yunlong Zhao Nov 2017

Characterization Of Highly Heterogeneous Heparin-Protein Complexes Using Novel Mass Spectrometry-Based Approaches, Yunlong Zhao

Doctoral Dissertations

Heparin-like glycosaminoglycan (GAG) is a family of polysaccharide involved in variety of physiological processes. They have potentials to interact with a broad range of proteins and many of them hold crucial values in regulation of protein functions. My dissertation addresses the significance and challenges in the field of heparin-mediated studies, with a focus on the questions in biological and analytical aspects, which are largely hindered by the structural heterogeneity and function diversity of heparin. My dissertation reports the efforts I made in the past few years with respect to the development of novel analytical strategies based on a combination of …


Nanoparticle As Supramolecular Platform For Delivery And Bioorthogonal Catalysis, Gulen Yesilbag Tonga Nov 2017

Nanoparticle As Supramolecular Platform For Delivery And Bioorthogonal Catalysis, Gulen Yesilbag Tonga

Doctoral Dissertations

Nanoparticles (NPs) are being investigated widely for many applications including imaging, drug delivery, therapeutics, materials, and catalysis due to their unique and tunable physical and chemical properties. Among NPs, gold nanoparticles (AuNPs) have attracted great attention due to ease of synthesis and surface functionalization, inertness of the core, biocompatibility, and functional versatility. Introducing supramolecular chemistry into the nanoparticle-based platforms brings out controllable properties, dynamic self assembly processes, and adjustable performance. My research has focused on the synthesis of AuNPs bearing different surface functionalities and their host-guest interactions with synthetic small molecules or commercially available hydrophobic catalysts for delivery and therapeutic …


Computational Studies Of Structure–Function Relationships Of Supported And Unsupported Metal Nanoclusters, Hongbo Shi Nov 2017

Computational Studies Of Structure–Function Relationships Of Supported And Unsupported Metal Nanoclusters, Hongbo Shi

Doctoral Dissertations

Fuel cells have been demonstrated to be promising power generation devices to address the current global energy and environmental challenges. One of the many barriers to commercialization is the cost of precious catalysts needed to achieve sufficient power output. Platinum-based materials play an important role as electrocatalysts in energy conversion technologies. In order to improve catalytic efficiency and facilitate rational design and development of new catalysts, structure–function relationships that underpin catalytic activity must be understood at a fundamental level. First, we present a systematic analysis of CO adsorption on Pt nanoclusters in the 0.2-1.5 nm size range with the aim …


Analyses Of Densely Crosslinked Phenolic Systems Using Low Field Nmr, Jigneshkumar Patel Nov 2017

Analyses Of Densely Crosslinked Phenolic Systems Using Low Field Nmr, Jigneshkumar Patel

Doctoral Dissertations

A uniform dispersion of reactants is necessary to achieve a complete reaction involving multi-components, especially for the crosslinking of rigid high-performance materials. In these reactions, miscibility is crucial for curing efficiency. This miscibility is typically enhanced by adding a third component, a plasticizer. For the reaction of the highly crystalline crosslinking agent hexamethylenetetramine (HMTA) with a strongly hydrogen-bonded phenol formaldehyde resin, furfural has been traditionally used as the plasticizer. However, the reason for its effectiveness is not clear. In this doctoral thesis work, miscibility and crosslinking efficiency of plasticizers in phenolic curing reactions are studied by thermal analysis and spectroscopic …


Protein-Nanoparticle Co-Engineering: Self-Assembly, Intracellular Protein Delivery, And Crispr/Cas9-Based Gene Editing, Rubul Mout Nov 2017

Protein-Nanoparticle Co-Engineering: Self-Assembly, Intracellular Protein Delivery, And Crispr/Cas9-Based Gene Editing, Rubul Mout

Doctoral Dissertations

Direct cytoplasmic delivery of gene editing nucleases such CRISPR/Cas9 systems and therapeutic proteins provides enormous opportunities in curing human genetic diseases, and assist research in basic cell biology. One approach to attain such a goal is through engineering nanotechnological tools to mimic naturally existing intra- and extracellular protein delivery/transport systems. Nature builds transport systems for proteins and other biomolecules through evolution-derived sophisticated molecular engineering. Inspired by such natural assemblies, I employed molecular engineering approaches to fabricate self-assembled nanostructures to use as intracellular protein delivery tools. Briefly, proteins and gold nanoparticles were co-engineered to carry complementary electrostatic recognition elements. When these …


Polyorganosiloxanes: Molecular Nanoparticles, Nanocomposites And Interfaces, Daniel H. Flagg Nov 2017

Polyorganosiloxanes: Molecular Nanoparticles, Nanocomposites And Interfaces, Daniel H. Flagg

Doctoral Dissertations

Five research projects described. First, a reproducible, lab-scale synthesis of MQ silicone copolymers is presented. MQ copolymers are commercially important materials that have been ignored by the academic community. One possible reason for this is the difficulty of controlling and reproducing the preparative copolymerizations that have been reported. A reproducible method for lab-scale preparation was developed that controls molecular weight by splitting the copolymerization into the discrete steps of sol growth from silicate precursor and end-capping by trimethylsiloxy groups. Characterization of MQ products implicates that they are composed of highly condensed, polycyclic structures. The MQ copolymers prepared in the first …


Spectroscopic Studies Of Gas-Phase Transition Metal Complexes Of Cations And Cluster Ions With Methane And Water, Christopher Copeland Nov 2017

Spectroscopic Studies Of Gas-Phase Transition Metal Complexes Of Cations And Cluster Ions With Methane And Water, Christopher Copeland

Doctoral Dissertations

The study of the non-covalent interactions between metals ions and ligands such as water and methane are key to understanding many processes including solvation, homogeneous catalysis and metals in biology. Similarly, the study of interactions between transition metal ions and cluster ions with hydrocarbons is of great importance in the understanding of C-H activation reactions which are involved in generation of fuels. Gas-phase metal complexes are good models for understanding the intrinsic interactions between the metal and the ligand. Understanding the mechanisms behind these interactions can be done by characterizing the structure and bonding in the molecular reactants, products, and …


Synthesis And Characterization Of Imidazole-Containing Conjugated Polymers, Jared D. Harris Nov 2017

Synthesis And Characterization Of Imidazole-Containing Conjugated Polymers, Jared D. Harris

Doctoral Dissertations

Semiconducting conjugated polymers hold tremendous promise as active layers for transformative electronic devices. This materials class benefits from the structural variety provided by organic chemistry such that highly tunable band structures are attainable for as-synthesized polymers. This dissertation describes the synthesis and characterization of novel imidazole-containing conjugated polymers for the purposes of (de)protonating the as-synthesized materials gaining conjugated poly(ionomer)s. (De)protonation easily enables band structure modification through manipulation of the materials’ ionization potential and electron affinity. Controlled exposure to acids and bases led to reversible (de)protonation observable via UV-visible and photoluminescence spectroscopies. (De)protonation’s effects on polymeric band structures was empirically and …


How The E. Coli Hsp70 Molecular Chaperone, Dnak, Binds A Client Protein, Joseph Tilitsky Oct 2017

How The E. Coli Hsp70 Molecular Chaperone, Dnak, Binds A Client Protein, Joseph Tilitsky

Masters Theses

Protein folding is essential for all cellular life. While some proteins are able to reach their folded state reliably using nothing but their amino acid sequence, a great number of essential proteins are unable to do so without the aid of molecular chaperones. One family of molecular chaperone, the Hsp70 family, is found in virtually all cell types and across all domains of life. Certain to the function of Hsp70s are how they bind their client proteins. Substantial effort has been expended to study how Hsp70s work on model peptides as a substrate mimic, but relatively little work has been …


Influence Of Biomimetic Chelating Packaging On Natural Antimicrobial Efficacy, Paul Castrale Oct 2017

Influence Of Biomimetic Chelating Packaging On Natural Antimicrobial Efficacy, Paul Castrale

Masters Theses

The iron chelating molecule, ethylenediaminetetraacetic acid (EDTA) is used in food applications for the preservation of oxidation prone ingredients. Research has suggested that EDTA is also capable of enhancing the antimicrobial effectiveness of various compounds including naturally-derived antimicrobials. With consumer demand for cleaner food labels, there remains an opportunity to introduce new chelating technology to replace synthetically-derived EDTA. Through photographting and chemical conversion, hydroxamic acid ligands were covalently bound to polypropylene films resulting in polypropylene-graft-poly(hydroxamic acid) (PP-g-PHA). The resulting films demonstrated an ability to chelate 64 nmol/cm2 from an iron saturated environment or 163 nmol/cm …


Microtransplantation Of Rat Brain Neurolemma Into Xenopus Laevis Oocytes To Study The Effect Of Environmental Toxicants On Endogenous Voltage-Sensitive Ion Channels, Edwin Murenzi Jul 2017

Microtransplantation Of Rat Brain Neurolemma Into Xenopus Laevis Oocytes To Study The Effect Of Environmental Toxicants On Endogenous Voltage-Sensitive Ion Channels, Edwin Murenzi

Masters Theses

Microtransplantation of mammalian neurolemma into Xenopus laevis oocytes has been used to study ion channels in terms of their structure and function in the central nervous system. Use of microtransplanted neurolemma is advantageous in that tissue can be obtained from various sources, ion channels and receptors are present in their native configuration and they can be used to evaluate numerous channelpathies caused by environmental toxicants. Here we show that Xenopus oocytes injected with fragments of rat brain neurolemma successfully express functional native ion channels that are assembled in their own plasma membrane. Using a high throughput two electrode voltage clamp …


Mechanistic Studies Of Peptide-Mediated Protein Transport Across Droplet-Interface Bilayers, Jing Huang Jul 2017

Mechanistic Studies Of Peptide-Mediated Protein Transport Across Droplet-Interface Bilayers, Jing Huang

Doctoral Dissertations

Pep-1 is a promising peptide tool that delivers proteins and peptides into cells with conserved bioactivity. Pep-1 has great potential because of the high efficiency and lack of toxicity. The mechanism of Pep-1-mediated transport is not fully understood. In my thesis, droplet-interface bilayer (DIB) has been used for the mechanistic studies of Pep-1. Here, DIB is developed for different functions such as quantitation of protein translocation, solution exchange to a formed bilayer and simultaneous observation of multiple membranes. Research work on Pep-1 with DIB reveals that the negative charge of the inner membrane leaflet plays a significant role in promoting …


Analytical Methods To Support Design And Optimization Of Protein Drug Conjugate: Focusing On Haptoglobin-Hemoglobin Complex As A Drug Carrier, Shengsheng Xu Jul 2017

Analytical Methods To Support Design And Optimization Of Protein Drug Conjugate: Focusing On Haptoglobin-Hemoglobin Complex As A Drug Carrier, Shengsheng Xu

Doctoral Dissertations

Acquired immunodeficiency syndrome (AIDS) remains one of the most serious public health challenges and a significant cause of mortality for certain populations. Despite the large number of antiretrovirals (mostly nucleotide and nucleoside analogs) developed in the past two decades, the inability of small molecule therapeutics to target HIV reservoirs directly creates a significant obstacle to their effective utilization. Indeed, achieving the desired therapeutic effect in the absence of the effective targeted delivery must rely on dosage escalation, which frequently causes severe toxicity. This problem may be solved by conjugation of antiretroviral agents to endogenous proteins (e.g., hemoglobin haptoglobin complex) that …


Characterization Of Electronic And Ionic Transport In Soft And Hard Functional Materials, Lawrence A. Renna Jul 2017

Characterization Of Electronic And Ionic Transport In Soft And Hard Functional Materials, Lawrence A. Renna

Doctoral Dissertations

Control over concurrent transport of multiple carrier types is desired in both soft and hard materials. For both types of materials, I demonstrate ways to characterize and execute governance over both electronic and ionic transport, and apply these concepts in the fabrication of devices with applications in conducting composites, photovoltaics, electrochemical energy storage, and memristors. In soft materials, such as polymers, the topology of the binary polymer mesoscale morphology has major implications on the charge/ion transport. Traditional approaches to co-continuous structures involve either using blends of polymers or diblock copolymers. In polymer blends, the structures are kinetically trapped and …


Stimuli Responsive Polymeric Nanogels For Hydrophobics & Hydrophilics Delivery, Kishore Raghupathi Jul 2017

Stimuli Responsive Polymeric Nanogels For Hydrophobics & Hydrophilics Delivery, Kishore Raghupathi

Doctoral Dissertations

Stimuli responsive nanoparticles have gained significant interest in the drug delivery research. The essential goal of drug delivery is to improve the efficacy of drugs by increasing their stability and bioavailability. Small molecule hydrophobic drugs face limited bioavailability due to their poor water solubility. Biologic drugs on the other hand, lack bioavailability because of their degradation by various enzymes encountered during blood circulation. For a systemic delivery approach, depending on site of drug action, delivery vehicles must pass through several contrasting micro environments before delivering the cargo selectively at the target site. Therefore, it is essential that a delivery vehicle …


Relationship Between Structure And Function In Nickel Proteins And Enzymes, Carolyn Carr Jul 2017

Relationship Between Structure And Function In Nickel Proteins And Enzymes, Carolyn Carr

Doctoral Dissertations

Nickel is a rarely used but biologically important metal that is utilized in all three domains of life. In nickel utilizing organisms there is a corresponding trafficking system specifically designed to capture nickel, deliver, and export excess nickel to prevent toxic effects. It is critical to understand the mechanisms by which organisms achieve metal selectivity to duplicate or disrupt this process for the benefit of human health and to further understanding of regulation mechanisms in biology. RcnR is a Ni(II) and Co(II) responsive transcriptional regulator in E. coli. The research reported in this dissertation focuses on the relationship between …


Vitreous Gel Physics, Svetlana Morozova Jul 2017

Vitreous Gel Physics, Svetlana Morozova

Doctoral Dissertations

The transparent vitreous, which fills the posterior cavity of the eye, is incredibly engineered. The charged polyelectrolyte hyaluronic acid (HA) network swells to maintain the pressure in the eye, while stiff collagen type II bundles help absorb any external mechanical shock. Our investigations have contributed to a few key developments related to the physical properties of the vitreous: (1) The stiff collagen network that supports the soft gel network is self-assembled from single triple-helix collagen proteins. Electrostatic interactions drive this assembly, such that the size and concentration are optimized at physiological salt concentrations. The width of the assemblies remarkably changes …


Mechanistic Studies Of Proton Gradient-Driven Protein Translocation By Droplet-Interface Bilayer Techniques, En-Hsin Lee Jul 2017

Mechanistic Studies Of Proton Gradient-Driven Protein Translocation By Droplet-Interface Bilayer Techniques, En-Hsin Lee

Doctoral Dissertations

Transmembrane proton gradient plays a fundamental role in protein translocation across cellular membranes, including the transport of secreted enzymes from bacterial pathogens into host cells. Much attention has been devoted to understanding the machinery of such delivery and how it functions. Over the past decade, translocation of anthrax toxin has been widely studied not only because of its central role in the deadly pathogenesis of Bacillus anthracis, but also because that it is one of the most tractable toxins and thus serves as an attractive model for studying the translocation machinery that is dependent on proton gradient across membrane. …


New Mass Spectrometric Methods For Studying Proteins In Solution And In The Gas Phase, Zhe Zhang Mar 2017

New Mass Spectrometric Methods For Studying Proteins In Solution And In The Gas Phase, Zhe Zhang

Doctoral Dissertations

This dissertation focuses on the mass spectrometric based methods for studying protein structures in solution phase and in gas phase. Protein structure is important to study because it is related to many disease mechanism and related therapies. The relationship between protein structures in solution phase and in gas phase has been investigated. Especially, the electrostatic interaction is characterized by mass spectrometry (MS). A HDX method has been developed to study protein oligomer kinetics and applied to study β-2-microglobulin (β2m) oligomerization. This dissertation firstly focuses on the relationship between protein gas phase structure and solution phase structure. We studied the structures …


Thiol-Ene Chemistry As An Enabler Of New Polymer Structures And Architectures, Joel M. Sarapas Mar 2017

Thiol-Ene Chemistry As An Enabler Of New Polymer Structures And Architectures, Joel M. Sarapas

Doctoral Dissertations

This dissertation focuses on two distinct projects: the synthesis and design of novel cell penetrating peptides mimics (CPPMs), and the implementation of the thiol-ene click reaction to generate new polymer architectures and chemistries. Guanidinium-rich CPPMs were generated through both ROMP and RAFT polymerizations, allowing for a comparison to be made across polymer backbone chemistries with respect to both siRNA and protein cellular internalization. A particularly effective methacrylate derived block copolymer was able to deliver siRNA to nearly an entire Jurkat T cell population. The thiol-ene reaction was implemented initially within the context of improving material design for solid polymer electrolytes …


Analysis Of Gold Nanoparticles And Their Use With Laser Desorption/Ionization Mass Spectrometry, Alyssa Marsico Mar 2017

Analysis Of Gold Nanoparticles And Their Use With Laser Desorption/Ionization Mass Spectrometry, Alyssa Marsico

Doctoral Dissertations

Gold nanoparticles (AuNPs) have many unique properties that make them attractive for use in various biological applications. Laser desorption/ionization mass spectrometry (LDI-MS) has been used to monitor AuNPs in complex biological samples but there are still many ways in which AuNPs can be used with MS. In this dissertation, the use of AuNPs to assist in analyte ionization has been investigated. Their ability to enhance signal from biomolecules based on their surface chemistry, size, aggregation and method of deposition has been studied. The first use of an inkjet printer to create surfaces from which analytes can be sampled is discussed …


Dopant-Defect Engineering In Strontium Titanate-Based Materials, Keith Lehuta Mar 2017

Dopant-Defect Engineering In Strontium Titanate-Based Materials, Keith Lehuta

Doctoral Dissertations

Strontium titanate is a wide gap oxide perovskite that has been studied for numerous applications. Its potential use as a photocatalyst is limited due to only being able to utilize UV light. The introduction of metal dopant ions has been shown to alter the band structure to allow visible light photocatalysis, as well as alter the materials properties for other applications. This work will look to better explain the process of transition metal dopant ion incorporation and how the dopant ion can affect the defect chemistry of the material. The use of dopant specific spectroscopies, such as electron paramagnetic resonance …


Gold Nanoparticle Biodistributions And Stability In Vivo From Mass Spectrometric Imaging, Sukru Gokhan Elci Mar 2017

Gold Nanoparticle Biodistributions And Stability In Vivo From Mass Spectrometric Imaging, Sukru Gokhan Elci

Doctoral Dissertations

Their smaller size, inherent non-toxicity and tunable properties of gold nanoparticles (AuNPs) attract researchers for their use in biological applications such as drug delivery, imaging and therapeutics. Understanding the in vivo fate of these AuNPs are essential for their potential effects in both the environment and the body. In this dissertation, mass spectrometric imaging methods using laser ablation inductively-coupled plasma mass spectrometry (LA-ICP-MS) and laser desorption/ionization (LDI-MS) have been investigated to monitor the in vivo fate of AuNPs. AuNP injected mouse tissue samples can be obtained and readily imaged to track the injected AuNPs using these methods. A first-ever imaging …


High Energy Density In Azobenzene-Based Materials For Photo-Thermal Batteries Via Controlled Polymer Architecture And Polymer-Solvent Interactions, Seung Pyo Jeong, Lawrence A. Renna, Connor J. Boyle, Hyunwook S. Kwak, Edward Harder, Wolfgang Damm, Dhandapani Venkataraman Jan 2017

High Energy Density In Azobenzene-Based Materials For Photo-Thermal Batteries Via Controlled Polymer Architecture And Polymer-Solvent Interactions, Seung Pyo Jeong, Lawrence A. Renna, Connor J. Boyle, Hyunwook S. Kwak, Edward Harder, Wolfgang Damm, Dhandapani Venkataraman

Chemistry Department Faculty Publication Series

Energy densities of ~510 J/g (max: 698 J/g) have been achieved in azobenzene-based syndiotactic-rich poly(methacrylate) polymers. The processing solvent and polymer-solvent interactions are important to achieve morphologically optimal structures for high-energy density materials. This work shows that morphological changes of solid-state syndiotactic polymers, driven by different solvent processings play an important role in controlling the activation energy of Z-E isomerization as well as the shape of the DSC exotherm. Thus, this study shows the crucial role of processing solvents and thin film structure in achieving higher energy densities.


Comparative Study Of Multicellular Tumor Spheroid Formation Methods And Implications For Drug Screening, Maria F. Gencoglu, Lauren E. Barney, Christopher L. Hall, Elizabeth A. Brooks, Alyssa D. Schwartz, Daniel C. Corbett, Kelly R. Stevens, Shelly Peyton Jan 2017

Comparative Study Of Multicellular Tumor Spheroid Formation Methods And Implications For Drug Screening, Maria F. Gencoglu, Lauren E. Barney, Christopher L. Hall, Elizabeth A. Brooks, Alyssa D. Schwartz, Daniel C. Corbett, Kelly R. Stevens, Shelly Peyton

Chemical Engineering Faculty Publication Series

Improved in vitro models are needed to better understand cancer progression and bridge the gap between in vitro proof-of-concept studies, in vivo validation, and clinical application. Multicellular tumor spheroids (MCTS) are a popular method for three-dimensional (3D) cell culture, because they capture some aspects of the dimensionality, cell–cell contact, and cell–matrix interactions seen in vivo. Many approaches exist to create MCTS from cell lines, and they have been used to study tumor cell invasion, growth, and how cells respond to drugs in physiologically relevant 3D microenvironments. However, there are several discrepancies in the observations made of cell behaviors when comparing …