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Studying Nanoparticle/Cell And Nanoparticle/Biosurface Interaction With Mass Spectrometry, Singyuk Hou
Studying Nanoparticle/Cell And Nanoparticle/Biosurface Interaction With Mass Spectrometry, Singyuk Hou
Masters Theses
Nanoparticles (NPs) have been used widely in various fields ranging from biomedical applications to life science due to their highly tunable properties. It is essential to understanding how NPs interact with biological systems of interest, therefore, analytical platforms to efficiently track NPs from cell to animal level are essential. In this thesis, laser desorption ionization mass spectrometry (LDI-MS) and inductively-coupled plasma mass spectrometry (ICP-MS) has been developed and applied to quantify NP/cell and NP/biological surface interactions. These two methods provide fast, label-free and quantitative analysis. New capability of LDI-MS to differentiate cell surface-bound and internalized NPs were established and ICP-MS …
Molecular Interpretation Of A Trigger For Controlling An Amine Isocyanate Polyurethane Reaction, Katherine V. Carrasquillo
Molecular Interpretation Of A Trigger For Controlling An Amine Isocyanate Polyurethane Reaction, Katherine V. Carrasquillo
Masters Theses
The temperature profile needed to complete the reaction between the sodium-diamine complex and the isocyanate terminated prepolymer has been established. The sodium diamine complex has the advantage of blocking the nearly instantaneous reaction between the diamine and isocyanate from taking place until it is released at elevated temperatures. Because of its low melting temperature (~40 °C) and its low molecular weight (low viscosity), this chain extension reaction is not dependent on the participation of the prepolymer. Instead, the rate of reaction is dependent on the dissolution of the 4,4’-methylenedianiline (MDA) complex into the system. The dissolution of the MDA complex …
Utilizing In Silico And/Or Native Esi Approaches To Provide New Insights On Haptoglobin/Globin And Haptoglobin/Receptor Interactions, Ololade Fatunmbi
Utilizing In Silico And/Or Native Esi Approaches To Provide New Insights On Haptoglobin/Globin And Haptoglobin/Receptor Interactions, Ololade Fatunmbi
Doctoral Dissertations
Haptoglobin (Hp), an acute phase protein, binds free hemoglobin (Hb) dimers in one of the strongest non-covalent interactions known in biology. This interaction protects Hb from causing potentially severe oxidative damage and limiting nitric oxide bioavailability. Once Hb/Hp complexes are formed, they proceed to bind CD163, a cell surface receptor on macrophages leading to complex internalization and catabolism. Myoglobin, (Mb) a monomeric protein, that is normally found in the muscle but can be released into the blood in high concentrations during myocardial injury, is homologous to Hb and shares many conserved Hb/Hp interface residues. Both monomeric Hb and Mb species …
Contact Angles And Contact Lines Around Particles At Isotropic And Anisotropic Liquid Interfaces, Nesrin Senbil
Contact Angles And Contact Lines Around Particles At Isotropic And Anisotropic Liquid Interfaces, Nesrin Senbil
Doctoral Dissertations
Liquid interfaces, capillarity and self-assembly of particles at interfaces are important in nature and technology. When a particle is adsorbed to a liquid interface, the contact line of the particle with the liquid interface and the associated contact angle are the crucial parameters that drive assembly of the particles. We looked at how the shape of the liquid interface and the shape of the particle affect the contact angle and the shape of the contact line. We used millimeter-sized PDMS-coated glass spheres and measured the contact angles at isotropic (planar) and anisotropic interfaces (saddle and cylindrical in shape). Anisotropy of …
Inkjet Printing For Biosensing And Security Applications, Brian Creran
Inkjet Printing For Biosensing And Security Applications, Brian Creran
Doctoral Dissertations
The adaptation of inkjet printing technology has recently been used to create controlled high throughput micro- and nano-scaled structures. Coupling this technique with gold nanoparticles in our research has produced new platforms for biosensors, chemical patterning, and anti-counterfeiting applications. In this presentation, we will highlight promising fabrication strategies including the development of test strips for the determination of bacteria in drinking water as well as the use of patterned nanoparticles for security applications.
Impact Of Fabrication Parameters On The Internal Structure Of Poly(3-Hexylthiophene) Nanoparticles, Dana Desiree Algaier
Impact Of Fabrication Parameters On The Internal Structure Of Poly(3-Hexylthiophene) Nanoparticles, Dana Desiree Algaier
Doctoral Dissertations
Morphological control of organic functional materials is central to understanding and improving upon current technologies. The ability to create hierarchical assemblies with purposeful design from nano to meso scale has remained largely unattainable. This body of work aims to provide a foundation for creating nanoscale domains of poly (3-hexylthiophene) (P3HT) that can be used as building blocks to larger scale assemblies. We present a method for the fabrication of P3HT nanoparticles on the ability to vary the particle size and more importantly, the internal structure. We have identified the oil phase and surfactant as parameters able to influence the nature …
From Molecular Scale To Mesoscale: Establishing Structural Control Organic Photovoltaics Using Organic Nanoparticles, Timothy S. Gehan
From Molecular Scale To Mesoscale: Establishing Structural Control Organic Photovoltaics Using Organic Nanoparticles, Timothy S. Gehan
Doctoral Dissertations
Organic photovoltaic devices use an active layer of organic materials that absorbs light and creates free charges to generate electricity. Such organic photovoltaics have many desirable properties as the final devices can be very lightweight, thin, flexible, have low manufacturing costs, and be semitransparent. These properties make them particularly advantageous for myriad of applications: e.g., use on non-planar surfaces, as tinted coatings on windows, any use for charging low power devices. One of the biggest problems preventing organic photovoltaics from being commercialized is controlling the packing of the organic materials within the active layer from the molecular scale through the …
Conjugated Polymers In Thermoelectric Composites And Small Molecules For High Light Absorptivity, Murat Tonga
Conjugated Polymers In Thermoelectric Composites And Small Molecules For High Light Absorptivity, Murat Tonga
Doctoral Dissertations
Over the past several decades with increasing of global energy demand, thermoelectric materials have gained considerable attention due to their unique ability to directly convert heat to electricity. In addition to inorganic semiconductors, polymers are potential candidates for high-performance thermoelectric applications due to their intrinsic advantages such as low thermal conductivity, solution processability, and roll-to-roll production, lightweight, and flexible thermoelectric modules. This thesis provides an insight into the emerging field of organic thermoelectrics, more specifically, thermoelectric power generation based on the composites of conducting polymers (MEH-PPV, P3HT and PEDOT:PSS) and carbon nanotubes (SWNT, SWNT-COOH, SWNT-OH and MWNT). A substantial portion …
Quantum Calculations Of Aldol Condensation In Acidic Zeolites, Angela N. Migues
Quantum Calculations Of Aldol Condensation In Acidic Zeolites, Angela N. Migues
Doctoral Dissertations
We have used Density Functional Theory to model the mixed aldol condensation reaction catalyzed by acidic zeolites. We have studied the convergence of barriers for the keto-enol tautomerization of acetone in cluster models of HZSM-5 and HY ranging in size from 3-37T. A key finding was that activation barriers for keto-enol tautomerization of acetone in both zeolites (~20 kcal/mol) are significantly higher than those for the condensation reaction between the acetone enol and formaldehyde in 11T cluster models of HZSM-5 and HY. Moreover we found that three zeolite clusters of HZSM-5, similarly sized but including different structural features of the …
Photochemical Tools For Fluorescent Labeling Of Endogenous Proteins, Stephen T. Mccarron
Photochemical Tools For Fluorescent Labeling Of Endogenous Proteins, Stephen T. Mccarron
Doctoral Dissertations
The study of the dynamic movements of membrane bound proteins is typically achieved through an exogenously applied fluorescent tag or genetic modification of a receptor of interest to spatiotemporally monitor protein location. Techniques often used for labeling proteins include overexpression of a fluorescent protein such as GFP fused to a target protein or the application of antibodies. These methods benefit from superb specificity towards a receptor of interest, but may impose unforeseen consequences when studying natural protein movements. Thus, it is advantageous to development small, modular probes that would allow for visualization of endogenous membrane bound receptors in a minimally …
Morphology Evolution Mechanisms Of Low Band Gap Polymer-Based Photovoltaics, Sunzida Ferdous
Morphology Evolution Mechanisms Of Low Band Gap Polymer-Based Photovoltaics, Sunzida Ferdous
Doctoral Dissertations
An optimal nanoscale phase separation between the donor (generally, a conjugated polymer) and the acceptor (generally, a fullerene derivative) materials is one of the major requirements for obtaining high efficiency organic photovoltaic (OPV) device. Recent methods of controlling such nanostructure morphology in a bulkheterojunction (BHJ) OPV device involve addition of a small amount of solvent additive to the donor and acceptor solutions. The idea is to retain the acceptor materials into the solution for a longer period of time during the film solidification process, thus allowing the donor material to crystallize earlier. The ultimate morphology resulting from the solvent casting …
Protein Charge Anisotropy Mediated Self-Association And Phase Separation, Daniel P. Seeman
Protein Charge Anisotropy Mediated Self-Association And Phase Separation, Daniel P. Seeman
Doctoral Dissertations
Protein charge anisotropy results from the asymmetric distribution of charged residues on the exterior of a particular protein. Interactions between proteins and other macromolecules can be described in terms of attractive electrostatics; since electrostatic free energies, at optimal I, are on the order of kT, it is unlikely that such associations would result in desolvation, thus it is reasonable to consider such intermolecular attractions as being mediated by hydrated protein surfaces. Such interactions can be broken down in terms of a single protein interacting with a range of “binding partners”, including (1) protein-protein interactions, (2) protein-polymer interactions, and …
Polymer And Fullerene Zwitterions: From Synthesis To Solar Cells, Zachariah A. Page
Polymer And Fullerene Zwitterions: From Synthesis To Solar Cells, Zachariah A. Page
Doctoral Dissertations
This thesis describes the synthesis and applications of hydrophilic conjugated polymers and fullerenes containing dipole-inducing pendent groups. The pendent groups include tertiary amines, sulfobetaine (SB) zwitterions, quaternary ammoniums, and sulfonates, providing solubility in polar solvents. Particular emphasis is placed on zwitterions functalized structures. Suzuki-Miyaura (SM) and Horner-Wadsworth-Emmons (HWE) coupling reactions proved valuable for the preparation of the hydrophilic conjugated polymers, while the Prato reaction afforded the functional fulleropyrrolidines. Ultraviolet photoelectron spectroscopy (UPS) probed the interactions between the hydrophilic conjugated polymers and conductive metal substrates. In particular, UPS revealed that conjugated polymer zwitterions (CPZs) substantially reduce work function (Φ) of metals, …
Responsive Supramolecular Assemblies Based On Amphiphilic Polymers And Hybrid Materials, Longyu Li
Responsive Supramolecular Assemblies Based On Amphiphilic Polymers And Hybrid Materials, Longyu Li
Doctoral Dissertations
The design and synthesis of responsive supramolecular assemblies are of great interest due to their applications in a variety of areas such as drug delivery and sensing. We have developed a facile method to prepare self-crosslinking disulfide-based nanogels derived from an amphiphilic random copolymer containing a hydrophilic oligo-(ethylene glycol)-based side-chain functionality and a hydrophobic pyridyl disulfide functional group. This thesis first provides a concept of studying the influence of Hofmeister ions on the size and guest encapsulation stability of a polymeric nanogel. The size and core density of nanogel can be fine-tuned through the addition of both chaotropes and kosmotropes …
Chemical Biology-Based Probes For The Labeling Of Targets On Live Cells, Amanda M. Hussey
Chemical Biology-Based Probes For The Labeling Of Targets On Live Cells, Amanda M. Hussey
Doctoral Dissertations
Proper detection is the key to studying any processes on the cellular scale. Nowhere is this more evident than in the tight space which confines the synaptic cleft. Being able to ascertain the location of receptors on live neurons is fundamental to our understanding of not only how these receptors interact and move inside the cell but also how neurons function. Most detection methods rely on significantly altering the receptor; both tagging with a fluorescent protein or targeting the receptor by a fluorescent reporter in the form of a small molecule causes significant difficulties. These localization techniques often result in …
Design And Application Of Organic Electronic Materials: Pendant Tuning In Polymeric And Molecular Systems, Jonathan S. Tinkham
Design And Application Of Organic Electronic Materials: Pendant Tuning In Polymeric And Molecular Systems, Jonathan S. Tinkham
Doctoral Dissertations
Designing and synthesizing materials for use in organic electronic materials requires fine control over their optical and electronic properties. Variations through substitution can be used to tune solubility and electronic properties, but this can result in degradation of other properties. Substitution with orthogonal pendant groups in both molecular and polymeric systems has the potential for allowing tunability while decreasing the perturbation of other desirable properties of the parent system. This idea was explored through experimental and computational work. Computational modelling was used to understand and predict the properties of molecular and polymeric systems to narrow the wide number of choices …
Inhibition And Cofactor Targeting Of Hypoxia-Sensing Proteins, Cornelius Y. Taabazuing
Inhibition And Cofactor Targeting Of Hypoxia-Sensing Proteins, Cornelius Y. Taabazuing
Doctoral Dissertations
Hypoxia Inducible Factor (HIF) is a transcription activator considered to be the main regulator of O2 homeostasis in humans. The transcriptional ability of HIF is regulated by the Fe2+/αKG-dependent enzyme, Factor Inhibiting HIF (FIH). FIH uses molecular oxygen to catalyze hydroxylation of an asparagine residue (Asn803) in the C-terminal transactivation domain (CTAD) of the HIFα subunit, abrogating HIF target gene expression. The mechanism of FIH and other αKG-dependent oxygenases involves the ordered sequential binding of αKG, substrate, and O2, which becomes activated to form a reactive ferryl intermediate that hydroxylates the substrate. The …
Transferrin-Based Therapeutics And Analytical Methods To Characterize Them, Son N. Nguyen
Transferrin-Based Therapeutics And Analytical Methods To Characterize Them, Son N. Nguyen
Doctoral Dissertations
Modern development of medicine requires detailed characterization by state-of-the art analytical techniques that can be used to analyze covalent structure, conformations and protein-receptor interaction to quantitatively measure biodistribution of protein therapeutics. Mass spectrometry has already become an indispensable tool facilitating all stages of protein drug development. Particularly, this work has demonstrated the tremendous potential of electrospray ionization (ESI) mass spectrometry (MS) in this arena by providing invaluable information beyond mass measurement that can be used to optimize protein drug conjugate structures during early stages of development, and to further catalyze drug design efforts. Additionally, a new sensitive and selective method …
Structure-Property Relationships At The Nano-Bio Interface: Engineering The Nanoparticle Surface For Immunomodulation, Daniel Fernando Moyano Marino
Structure-Property Relationships At The Nano-Bio Interface: Engineering The Nanoparticle Surface For Immunomodulation, Daniel Fernando Moyano Marino
Doctoral Dissertations
Each year, a variety of novel nanomaterials are being developed with the objective of treating different diseases. However, since nanomaterials are foreign to the human body, one of the principal factors that limit their use is the encounter with the first line of defense from the body: the immune system. If this interaction is not taken into account, an undesired recognition takes place and the efficiency of nanoparticle based therapies is dramatically reduced. As such, understanding the rules that govern this recognition is of prime importance in the field of nanomedicine. Following this line of thoughts (the driving force), the …
Physicochemical And Toxicological Assessment Of Antimicrobial Ε-Polylysine-Pectin Complexes, Cynthia L. Lopez Pena
Physicochemical And Toxicological Assessment Of Antimicrobial Ε-Polylysine-Pectin Complexes, Cynthia L. Lopez Pena
Doctoral Dissertations
ε-Polylysine is an appealing FDA-approved, all natural antimicrobial biopolymer effective against a wide range of microorganisms. Its implementation is greatly limited by its strong cationic charge, which has been linked to instability in food systems, perceived astringency and bitterness, and the ability to inhibit lipid digestion. Previous studies have shown that controlled complexation of ε-polylysine with anionic pectin is able to prevent instability and astringency in simplified model food systems, while maintaining the antimicrobial character of polylysine. Isothermal titration calorimetry, micro-electrophoresis, microscopy, and turbidity analyses of the stability of electrostatic pectin-polylysine complexes in the presence of strongly anionic κ-carrageenan, and …
Time-And Polarization-Resolved Photoluminescence Studies Of Directional Coupling In Isolated Semiconductor Nanostructures, Joelle A. Labastide
Time-And Polarization-Resolved Photoluminescence Studies Of Directional Coupling In Isolated Semiconductor Nanostructures, Joelle A. Labastide
Doctoral Dissertations
TIME-AND POLARIZATION-RESOLVED STUDIES OF DIRECTIONAL COUPLING IN ISOLATED SEMICONDUTOR NANOSTRUCTURES MAY 2015 JOELLE A. LABASTIDE, B.S. UNIVERSITY OF MASSACHUSESSTS AMHERST Ph.D., UNIVERSITY OF MASSACHUSETTS AMERST Directed by Professor Michael D. Barnes Development of new materials and assembly strategies for organic semiconductor-based optoelectronic materials is a problem of great interest worldwide, as researchers seek to resolve the questions pertinent to the creation of inexpensive, reliable, efficient, and stable active layer components. Organic semiconductors as the basis for photovoltaic active layers show significant promise for these applications. However, there is still much that needs to be understood about the molecular scale structural …
Tunable Photonic Multilayers From Stimulus-Responsive, Photo-Crosslinkable Polymers, Maria C. Chiappelli
Tunable Photonic Multilayers From Stimulus-Responsive, Photo-Crosslinkable Polymers, Maria C. Chiappelli
Doctoral Dissertations
This dissertation describes the synthesis of photo-crosslinkable copolymers and their utilization for the fabrication and testing of tunable and responsive one-dimensional (1D) photonic multilayers. Photonic multilayers exhibit structural color due to the interference of incident light at layer interfaces, providing a convenient route towards optically responsive materials that do not rely on potentially light- or oxygen-sensitive chromophore-containing pigments and dyes. A fabrication technique based on sequential spin-coating and crosslinking of photo-crosslinkable polymers is used to assemble tunable and responsive photonic multilayers. Chapter One introduces the fundamental underlying principles of 1D photonic structures and explores their importance in a variety of …
Catalytic Methane Dissociative Chemisorption Over Pt(111): Surface Coverage Effects And Reaction Path Description, Inara Colon-Diaz
Catalytic Methane Dissociative Chemisorption Over Pt(111): Surface Coverage Effects And Reaction Path Description, Inara Colon-Diaz
Masters Theses
Density functional theory calculations were performed to study the dissociative chemisorption of methane over Pt(111) with the idea of finding the minimum energy path for the reaction and its dependence on surface coverage. Two approaches were used to evaluate this problem; first, we used different sizes of supercells (2x2, 3x3, 4x4) in order to decrease surface coverage in the absence of pre-adsorbed H and CH3 fragments to calculate the energy barriers of dissociation. The second approach uses a 4x4 unit cell and surface coverage is simulated by adding pre-absorbed H and CH3 fragments. Results for both approaches show …
Design, Synthesis, And Bio Relevant Applications Of Zwitterionic Amphiphilic Macromolecular Assemblies, Rajasekhar Reddy Rami Reddy
Design, Synthesis, And Bio Relevant Applications Of Zwitterionic Amphiphilic Macromolecular Assemblies, Rajasekhar Reddy Rami Reddy
Doctoral Dissertations
Supramolecular nanoassemblies capable of reducing non-specific interactions with biological macromolecules, such as proteins, are of great importance for various biological applications especially for targeted drug delivery therapeutics. Recently, zwitterionic materials have been shown to reduce non-specific interactions with biomolecules, owing both to their charge neutrality and their ability to form strong hydration layer around zwitterions via electrostatic interactions. This dissertation focuses on design, synthesis, thorough characterization, and applications of zwitterionic amphiphilic dendrimers and polymeric materials. Firstly, A new triazole-based zwitterionic moiety was conceived and incorporated as the hydrophilic functionality in facially amphiphilic dendrons. Self-assembly characteristics and the structural and functional …
Design, Syntheses And Study Of Bodipy-Based Materials For Use As Electron Transporters In Organic Electronics, Ambata Poe
Doctoral Dissertations
Organic photovoltaics (OPVs) are desirable for the harvesting of solar energy. They provide distinct advantages over their inorganic counterparts, especially the high absorption coefficients of organic materials and their ability to be processed using inexpensive solution methods. This allows for potential development of lightweight and flexible devices for portable electronics. One of the drawbacks of organic photovoltaics is the low power conversion efficiency of the devices. Efforts to improve the efficiency often take place through molecular design of the electron rich donor material to improve light absorption of the active layer. However, significantly less effort has been put into modifying …
Functional Nanostructures From Nanoparticle Building Blocks, Jimmy Lawrence
Functional Nanostructures From Nanoparticle Building Blocks, Jimmy Lawrence
Doctoral Dissertations
Advances in the synthetic strategies of engineered nanomaterials, multifunctional molecules and polymers have opened pathways for the development of functional nanomaterials having unique optoelectronic, mechanical, and biological properties. By designing the chemistry of surface ligands, the organic interface of nanoparticles, one can further the versatility and utilization of engineered nanomaterials, opening pathways for breakthroughs in sensing, catalysis, and delivery using nanomaterials. This thesis describes the synthesis and characterization of small molecule and polymer ligand functionalized inorganic nanoparticles (e.g., metal, semiconducting). Embedding specific chemical functionality into the ligand periphery of nanoparticles enables the resulting functional nanoparticles to react selectively …
Stimuli-Responsive Supramolecular Assembly, Disassembly And Implications, Jing Guo
Stimuli-Responsive Supramolecular Assembly, Disassembly And Implications, Jing Guo
Doctoral Dissertations
Stimuli-responsive systems have attracted wide interest due to their applications in a variety of areas such as drug delivery and sensing. Stimuli-responsive systems that are triggered by secondary biological changes have been studied extensively. Primary biological changes, such as protein imbalances and enzymatic activity, are intrinsic to certain types of diseases, and thus have drawn increasing attention in triggering stimuli-responsive systems in areas such as drug delivery. This thesis first provides a concept of increasing stimuli-responsive selectivity by designing a system that only responds in the concurrent presence of two complementary primary biological stimuli, protein and enzyme. A dendritic assembly …
Aggregation And Interfacial Behavior Of Charged Surfactants In Ionic Liquids, Lang Chen
Aggregation And Interfacial Behavior Of Charged Surfactants In Ionic Liquids, Lang Chen
Doctoral Dissertations
Room-temperature ionic liquids (ILs) exhibit a unique set of properties, leading to opportunities for numerous applications such as green solvents, batteries and lubricants. Their properties can be greatly tuned and controlled by addition of surfactants. It is therefore critical to obtain a better understanding of the aggregation and interfacial behavior of surfactants within ILs. Firstly, the phase diagram and aggregation isotherms of surfactants in several distinct ILs were investigated by solubility and tensiometry. A connection between solubility of the surfactant and the physical properties of the underlying ionic liquid was established. We found that the interfacial energy was crucial in …
Developing Fluorescent Sensors For The Bioimaging Of Chelatable Iron(Iii) Ions, Ziya Aydin
Developing Fluorescent Sensors For The Bioimaging Of Chelatable Iron(Iii) Ions, Ziya Aydin
Doctoral Dissertations
Iron is an essential element for the body and plays important roles in many metabolic processes. A transient labile iron pool (LIP) has been proposed to play key roles in cellular iron trafficking and metabolism. However, free iron ions (Fe3+ and Fe2+) in this pool are toxic and damaging to cells due to their involvement in the production of oxygen radicals. The damages may lead to aging and various diseases including stroke, cancer, and several neurological disorders like Parkinson’s disease, Alzheimer’s disease and atherosclerosis. Determination of free iron ions in cells may contribute to a better understanding …