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Full-Text Articles in Nanoscience and Nanotechnology
Fabrication Of Copper Nanoparticle/Graphene Oxide Composites And Reduction Of Copper Oxide Nanowires, Maged Elshatoury
Fabrication Of Copper Nanoparticle/Graphene Oxide Composites And Reduction Of Copper Oxide Nanowires, Maged Elshatoury
Electronic Theses and Dissertations, 2020-
The thesis reports the investigation of producing copper nanoparticle composites with graphene oxides (GO) using poly (sodium 4-styrenesulfonate) (PSS) and copper nanowires through the reduction of copper oxide nanowires using hydrazine. It was discovered that PSS improved the dispersity of GO and increased the absorption of copper ions on GO. An electrochemical reduction of GO/PSS/copper ion dispersion produced copper nanoparticles on GO surfaces. Reducing copper oxide nanowires on copper foils using hydrazine was achieved at a temperature where copper nanowires maintained their nanoscale structures.
Signal Enhancement Techniques For Nanoscale Infrared Spectroscopy Using Fractal Plasmonic Structures, Guntis Rutins
Signal Enhancement Techniques For Nanoscale Infrared Spectroscopy Using Fractal Plasmonic Structures, Guntis Rutins
Electronic Theses and Dissertations, 2020-
Exploring phenomena occurring at the molecular level is critical to deepen our understanding of the living world. However conventional analytical tools are often limited in both spatial resolution and sensitivity. In this work we evaluate how fractal plasmonic structures can be developed for Surface Enhanced InfraRed Absorption (SEIRA) substrates to boost the infrared fingerprint signal of unknown single entities such as nanomaterials, virus or other biological systems. In this thesis, we present an overview of developments using light-matter interaction to push the limit of spatial resolution and sensitivity (Chapter 1). We discuss technological advances that allow nanoscale infrared spectroscopy despite …
Nanoplasmonic Colorimetric Sensors For Detection Of Ammonia From Water And Urine, Zuriel Caribe
Nanoplasmonic Colorimetric Sensors For Detection Of Ammonia From Water And Urine, Zuriel Caribe
Electronic Theses and Dissertations, 2020-
Motivated by the need for inexpensive, simple, and portable devices for aqueous chemical analysis, we developed a nanoplasmonic colorimetric sensor capable of direct detection of wide range of chemicals. This novel sensor exploits the plasmonic resonance of metallic nanostructures with natural light to transduce changes in the chemical environment to changes in color, thus offering a simple route for real-time, in-situ, and low-cost analysis of aqueous chemical species. Due to its environmental and medical relevance, we chose aqueous ammonia to analyze and determine the efficacy and limit of detection of this sensing platform. For the metallic nanostructures we selected aluminium …
Impact Of Crowder Size On Actin Filament Assembly Kinetics, Bryan Demosthene
Impact Of Crowder Size On Actin Filament Assembly Kinetics, Bryan Demosthene
Electronic Theses and Dissertations, 2020-
Actin is an abundant and essential cytoskeletal protein that plays a central role in eukaryotic cell structure and motility. The intracellular environment where actin assembly occurs is crowded with various organelles, proteins, and macromolecules that limit the accessible volume for biomolecular reactions. Macromolecular crowding induces excluded volume effects influencing the activity of biological molecules as well as the shape and conformation of proteins. Crowding agents, such as polysaccharides or inert polymeric molecules, are used to mimic the conditions present in intracellular spaces and provide a better understanding of interactions inside the cell. Macromolecular crowding has been shown to affect actin …
Modulation Of Actin Filament Severing And Mechanics By Gelsolin In Varying Ph Conditions, Claire Toland
Modulation Of Actin Filament Severing And Mechanics By Gelsolin In Varying Ph Conditions, Claire Toland
Electronic Theses and Dissertations, 2020-
Actin is an essential cytoskeletal protein that plays a critical role in cell mechanics, structure and organization with the help of actin binding proteins (ABPs). Gelsolin is a calcium-dependent ABP that severs actin filaments and caps them at their barbed end, regulating cell motility and signaling through dynamic actin cytoskeleton remodeling. A recent study has indicated that low pH stabilizes the active conformations of gelsolin. Additionally, the binding of gelsolin to the barbed end of an actin filament induces a conformational change that propagates along the actin filament. However, it has not been well understood how the complex intracellular environments …
Nanofabrication And Characterization Of An Enzyme-Less Electrochemical Biosensor For Creatinine Detection, Anas Belharsa
Nanofabrication And Characterization Of An Enzyme-Less Electrochemical Biosensor For Creatinine Detection, Anas Belharsa
Electronic Theses and Dissertations, 2020-
This study will reveal the fabrication and development of an enzyme-less biosensor for creatinine detection. The biosensor involves a periodically patterned nano-porous TiO2 deposited with Au nanoparticles via e-beam evaporation and a layer of Imprinted Polymer (IP) of acrylamide and bis-acrylamide to obtain a heterostructure of I-Au-TiO2. The detection methods of creatinine are based on electrochemical measurements using Cyclic Voltammetry (CV), Electrochemical Impedance Spectroscopy (EIS) and Differential Pulse Voltammetry (DPV). The IP-Au-TiO2 sensor shows a detection LOD of 0.0949ng/mL and 0. 0.218ng/mL for EIS and DPV measurements, respectively. The nanofabricated biosensor was tested in the presents of urea, glucose, lactose, …
Synthesis Of Ruthenium Bipyridine Conjugated Antibiotic For Fluorescence Lifetime Imaging And Spectroscopy Aided Tracking In Citrus, Ryan Parente
Electronic Theses and Dissertations, 2020-
Antibiotic treatment of systemic bacterial plant pathogens is an established practice in many crops; however, in citrus it has only recently become available for growers to utilize against Huanglongbing disease. The preliminary efficacy of these treatments is uncertain due to the inability to track their presence in phloem. The need to monitor their movement in planta, especially their presence and translocation in vascular tissue, is a necessary step in clarifying their effectiveness. Previous work has shown the value of Fluorescence Lifetime Imaging (FLIM) in distinguishing between fluorescent probes and plant tissue autofluorescence, which is normally a barrier in photochemical studies …
The Synthesis Of Palladium-Platinum Core-Shell Nanoparticles With High Catalytic Peroxidase Activities For Biosensing Applications, Edwin Davidson
The Synthesis Of Palladium-Platinum Core-Shell Nanoparticles With High Catalytic Peroxidase Activities For Biosensing Applications, Edwin Davidson
Electronic Theses and Dissertations, 2020-
In recent years, peroxidase mimic nanostructures have attracted special interest due to their low cost, high stability, and high catalytic activity. Herein, we demonstrate the use of Pd-Pt nanocubes (NCs) to achieve the rapid and sensitive colorimetric detection of ascorbic acid (AA), commonly known as vitamin C. The colored signal generated by the catalyzed oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) by the decomposition of hydrogen peroxide (H2O2) is quenched in the presence of AA based on its antioxidant property. This colorimetric method attains a detection limit of 0.40 µM and a linear range from 0 to 15 µM, with good linearity. To …
Nano-Biophysical Approaches For Assessing Nanoparticle Interactions With Biological Systems, Zachary Untracht
Nano-Biophysical Approaches For Assessing Nanoparticle Interactions With Biological Systems, Zachary Untracht
Electronic Theses and Dissertations
Understanding interactions between nanoparticles and biological systems is fundamental for the development of emerging nano-biotechnology applications. In this thesis, I present an investigation of zinc oxide (ZnO) nanoparticles interactions with biomolecules in two separate studies. The first section of my thesis covers tracking and detection of ZnO nanoparticles using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). ZinkicideTM is a bactericidal ZnO nanoparticle which has been developed for agriculture. The characterization of Zinkicide in biological media and in solution has been difficult due to its high dispersibility and ultra-small size. SDS-PAGE is considered a golden standard for protein qualitative interpretations. In …
Synthesis Of Two-Dimensional Molybdenum Disulfide Nanostructures Using Molybdenum Trioxide Thin Film Via Chemical Vapor Depostion, Vanessa Charles
Synthesis Of Two-Dimensional Molybdenum Disulfide Nanostructures Using Molybdenum Trioxide Thin Film Via Chemical Vapor Depostion, Vanessa Charles
Electronic Theses and Dissertations
Two dimensional (2D) materials-based nanostructures have attracted much attention due to their unique properties which exhibit promising prospects for application in catalysis and energy storage devices. Control growth method is important in synthesizing these nanostructures. Chemical vapor deposition (CVD) is a powerful method that provides scalability and controllable way to grow high quality 2D materials-based nanostructures. Here, we report a novel CVD growth method of 2D molybdenum disulfide (MoS2) based different structures in which thin film of molybdenum trioxide (MoO3) was used as the source of molybdenum (Mo), while sulfur (S) powder was used for the chalcogen precursor. Precise control …
Development Of 3d Printed And 3d Metal-Based Micro/Nanofabricated, And Nano-Functionalized, Microelectrode Array (Mea) Biosensors For Flexible, Conformable, And In Vitro Applications, Charles Didier
Electronic Theses and Dissertations
Emerging fields such as "Organs on a Chip", disease modeling in vitro, stem cell manufacturing and wearable bioelectronics are demanding rapid development of 3D Microelectrode Arrays (MEAs) for electrical interfacing with biological constructs. The work reported in this thesis focuses on two developmental tracks: "Dynamic 3D MEAs" and metal microfabrication for 3D MEAs. In the first part of the thesis, we explore the capabilities and limitations of 3D printed microserpentines (µserpentines) and utilize these structures to develop dynamic 3D microelectrodes. Analytical modeling of µserpentines flexibility followed by integration into a flexible Kapton® package and PDMS insulation are demonstrated. These 3D …
Interplay Of Molecular And Nanoscale Behaviors In Biological Soft Matter, Nicholas Ciaffone
Interplay Of Molecular And Nanoscale Behaviors In Biological Soft Matter, Nicholas Ciaffone
Electronic Theses and Dissertations
The complexity of biological soft matter at the sub-micrometer level is fundamentally correlated to the functionalities at the larger scale. Reflecting the level of heterogeneities in the properties of systems remains challenging when probing small scales, due to the mismatch between the area surveyed with the tools offering nanoscale resolution, such as atomic force microscopy (AFM), and the scale of natural variations inherent to biology. Hence, to understand the physiological and mechanical alterations that occur within a single cell relative to a cell population, a multiscale approach is necessary. In this work we show that it is possible to observe …
Tunable Effect Of Metal Ions On Polyelectrolyte Mechanics, Angie Diaz
Tunable Effect Of Metal Ions On Polyelectrolyte Mechanics, Angie Diaz
Electronic Theses and Dissertations
Polyelectrolyte based hydrogel fibers can mimic extracellular matrix and have applications such as drug delivery and tissue scaffolding. Metal ions play a critical role in hydrogel fiber stability via electrostatic interactions, but knowledge of how they modulate mechanical properties of individual polyelectrolyte polymers is lacking. In this study, electrospun polyacrylic acid with chitosan is used as a model system to evaluate ferric ion effect on nanofiber mechanics. Using dark field microscopy imaging and persistence length analysis, we demonstrate that ferric ions modulate the bending stiffness of nanofibers. Young's modulus of individual nanofibers is estimated at values of a few kilopascals, …
A Multisystem Approach For The Characterization Of Bacteria For Sustainable Agriculture, Briana Lee
A Multisystem Approach For The Characterization Of Bacteria For Sustainable Agriculture, Briana Lee
Electronic Theses and Dissertations
The chemical, physical, and biological properties of bacteria developing resistance have been explored in animal based bacteria while plant bacteria have been largely neglected. Thus, the ability to probe changes in stiffness, adhesion, binding interactions and molecular traits of bacteria causing plant diseases is of great interest to develop a new generation of more potent, yet sustainable, pesticides. Our study aims to investigate the physical and chemical properties of bacterial systems, in particular their cell walls. Building upon this fundamental understanding of the cells, we also investigate the physicochemical responses associated to multivalent nanoparticle-based bactericide treatments on bacterial systems identified …
Size, Charge And Dose Dependent In-Vitro Kinetics Of Polystyrene Nanoparticles, Yasmine Abdellatif
Size, Charge And Dose Dependent In-Vitro Kinetics Of Polystyrene Nanoparticles, Yasmine Abdellatif
Electronic Theses and Dissertations
The aim of the study described herein is to quantify the in-vitro kinetics of internalization of polystyrene nanoparticles (PS NPs) by cells. We used different charges, sizes and doses of fluorescently labelled PS NPs. Nanoparticles were characterized with UV-Vis, Fluorescence emission Dynamic Light Scattering (DLS) and Zeta potential for knowing their absorption, fluorescence spectra, size, charge, respectively. Additionally, cell viability was tested to know the toxicity of PS NPs. The quantitative uptake, the kinetics profile and rate of uptake were studied by using a new in-vitro fluorescence assay. This was achieved quantitatively and qualitatively by fluorescent plate reader and confocal …
Fluorescence Lifetime Imaging And Spectroscopy Aided Tracking Of Zno And Cds:Mn/Zns/ N-Acetyl Cysteine (Nac) Quantum Dots In Citrus Plants, Torus Washington
Fluorescence Lifetime Imaging And Spectroscopy Aided Tracking Of Zno And Cds:Mn/Zns/ N-Acetyl Cysteine (Nac) Quantum Dots In Citrus Plants, Torus Washington
Electronic Theses and Dissertations
In this thesis, we present an efficacious way of tracking nanoparticle movement in plant tissue through the use of fluorescence lifetime imaging (FLIM) and spectroscopy as well as a review of nanoparticle uptake in plants and the proposed mechanisms governing them. Given the increasing number of nanomaterials in agriculture and society as a whole, proper imaging tools and proactive measures must be taken to track nanoparticle movement in plant tissues and create infrastructure and products to keep things sustainable and safe. Herein we report a ZnO comparable nanoparticle— a CdS:Mn/ZnS/ N-acetyl cysteine (NAC) quantum dot— which boasts longer lifetimes and …
High Power Continuous Wave Quantum Cascade Lasers With Increased Ridge Width, Ankesh Todi
High Power Continuous Wave Quantum Cascade Lasers With Increased Ridge Width, Ankesh Todi
Electronic Theses and Dissertations
Quantum Cascade Lasers have recently gained considerable attention for their capability to emit infrared radiation in a broad infrared spectral region, very compact dimensions, and high optical power/efficiency. Increasing continuous wave optical power is one of the main research directions in the field. A straightforward approach to increasing optical power in the pulsed regime is to increase number of stages in the cascade structure. However, due to a low active region thermal conductivity, the increase in number of stages leads to active region overheating in continuous wave operation. In this work, an alternative approach to power scaling with device dimensions …
Effects Of Surfactant Concentrations On Perovskite Emitters Embedded In Polystyrene, Eric Calkins
Effects Of Surfactant Concentrations On Perovskite Emitters Embedded In Polystyrene, Eric Calkins
Electronic Theses and Dissertations
With their simple fabrication, narrow light spectrum, and color tunability, a class of materials known as perovskites are emerging as promising candidates for light emission applications. These materials, when exposed to normal atmospheric conditions show significant degradation. Improved protection has been demonstrated by embedding perovskites in polymers. Furthermore, the addition of a surfactant into the precursor solution has been shown to increase stability and allow for color tuning by exploiting quantum confinement effects. However, the effects of surfactants typically used to stabilize perovskites in solution have not been explored in this polymer embedding strategy. Here we determine the physical and …
Freestanding Holey Thin Films For Renewable Energy Storage, Kyle Marcus
Freestanding Holey Thin Films For Renewable Energy Storage, Kyle Marcus
Electronic Theses and Dissertations
The rapid advancement of portable and wearable technologies has challenged research to improve upon current renewable battery energy storage systems. By using nanotechnology, it is now possible to access more of the energy storage theoretical values that have been unattainable thus far. We have developed a method to create freestanding holey thin films through combinations of electrochemical and chemical vapor deposition (CVD) techniques to be used in renewable energy storage systems. Freestanding thin films promote excellent contact between the residual conductive framework and any functionalized active component specific to the designed material. Without requiring any other additives, the as-prepared freestanding …
Mechanism Of Actin Bundle Assembly, Mechanics And Structure By Ion Interaction, Nicholas Castaneda
Mechanism Of Actin Bundle Assembly, Mechanics And Structure By Ion Interaction, Nicholas Castaneda
Electronic Theses and Dissertations
The assembly of actin filaments into bundles plays an essential role in mechanical strength and dynamic reorganization of cytoskeleton. Divalent counterions at high concentrations promote bundle formation through electrostatic attraction between charged filaments. Although it has been hypothesized that specific cation interactions may contribute to salt-induced bundling, molecular mechanisms of how salt modulates bundle assembly and mechanics are not well established. Here we determine the mechanical and dynamic properties of actin bundles with physiologically relevant cations. Using total internal reflection fluorescence (TIRF) microscopy, we measure the bending stiffness of actin bundles determined by persistence length analysis. We characterize real-time formation …