Doctor of Philosophy, University of Toledo, 2016, Chemistry

Nanoclusters are finite aggregations of 2-10,000 atoms that interact through synergistic effects to form materials with unique chemical and physical properties.1-5 The properties of nanoclusters have been shown to be size-dependent, and to have incongruous chemical and physical properties from the constituent bulk material.1-5 In recent years there has been an extraordinary scientific effort to establish size-evolutionary patterns to provide a fundamental understanding of the size-dependent properties of nanoclusters.1,3,5,6 The current size-evolutionary patterns for nanoclusters have yielded theoretical and synthetic models that have begun to rationalize and explain the origin of nanocluster properties.1, 3, 5, 7 The size-evolutionary models have shown that large surface-to-volume ratios, quantum confinement, and structural and energetic size effects are the dominating factors that influence the properties of nanoclusters.1-3,5,7 However, there is an obligation to continually revise and improve the current size-evolutionary models to provide a more accurate theory to bridge the understanding between atomic/molecular states, structural motifs at the metal surface interface, and condensed-phase physics.1, 3, 5, 7 M4Ag44(p-MBA)30 nanoclusters, where M is an alkali metal, have recently been shown to have exceptional stability, which confers unique traits to this molecule. In particular, the synthesis is straightforward, produces a truly single-sized molecular product, and has a quantitative yield. Here, we describe in detail the results of experimental and theoretical studies on the synthesis, structure, stability, and electronic and optical properties of M4Ag44(p-MBA)30, including ESI-MS, NMR, optical absorption, IR, TGA, and other measurements as well as DFT and TDDFT calculations. Additionally, the structure and facile synthesis of M4Ag44(p-MBA)30 has provided a “golden” opportunity to explore the effects of doping M4Ag44(p-MBA)30 with gold. This work has deepene (open full item for complete abstract)

Committee: Terry Bigioni PhD (Committee Chair); Dragan Isailovic PhD (Committee Member); Nikolas Podraza PhD (Committee Member); Joseph Schmidt PhD (Committee Member) Subjects: Chemistry; Materials Science; Metallurgy; Nanoscience; Nanotechnology

Master of Science (M.S.), University of Dayton, 2016, Aerospace Engineering

The United States Air Force believes that hypersonic flight opens a multitude of possibilities for the warfighter. One of the main propulsion systems for hypersonic flight is scramjet engines. These engines are currently ignited using a form of electric discharge and a primer fuel. This primer fuel system takes away valuable volume and weight in hypersonic vehicle designs. One alternative ignition method would be the utilization of plasmonic resonance to flash ignite aluminum nanoparticles. This process had been proven multiple times in the past and research has begun on characterizing how this ignition process can be affected. One that has not been researched to date has been how water content and agglomeration affect the energy needed for ignition to be achieved. To understand this functional dependence, aluminum nanoparticles were put through a series of trials with various levels of water content. Samples of particles were heated at 473.15 K to decrease water content and subsequently tested to determine the energy input needed for ignition. To understand the effects of increasing water content, particles were placed in an environment with at least 100% relative humidity for both 48 and 168 hours and then tested to determine the ignition energy needed. The results from the two humidified cases were compared with the data from a control group whose water content was not altered in a controlled manner. It was determined that by humidifying the particles the minimum energy needed for total ignition was lowered by approximately five percent on average while drying the particles increased the energy needed by approximately four percent on average.

Committee: Aaron Altman PhD (Advisor); Timothy Ombrello PhD (Advisor); David Myszka PhD (Committee Member) Subjects: Aerospace Engineering; Engineering; Nanoscience

PhD, University of Cincinnati, 2005, Engineering : Materials Science

In this project, phase transformations and precipitation behavior of Al-Cu nanoparticles were first studied. The nanoparticles were synthesized by a Plasma Ablation process and found to contain a 2∼5 nm thick adherent aluminum oxide scale, which prevented further oxidation. On aging, a precipitation sequence consisting of, nearly pure Cu precipitates to the metastable θ′ to equilibrium θ was observed. The structure of θ′ and its interface with the Al matrix has been characterized. Ultrafine Al-Cu nanoparticles (5∼25 nm) were also synthesized by inert gas condensation and their aging behavior was studied. These particles were found to be quite stable against precipitation. Secondly, pure Al nanoparticles were prepared by the Exploding Wire process and their sintering and consolidation behavior were studied. It was found that Al nanopowders could be processed to bulk structures with high hardness and density. Sintering temperature was found to have a dominant effect on density, hardness and microstructure. Sintering at temperatures >600 degree C led to breakup of the oxide scale, leading to an interesting nanocomposite composed of 100∼200 nm Al oxide dispersed in a bimodal nanometer-micrometer size Al matrix grains. And the randomly dispersed oxide fragments were quite effective in pinning the Al grain boundaries, preventing excessive grain growth and retaining high hardness. Cold rolling and hot rolling were effective methods for attaining full densification and high hardness. Thirdly, the microstructure evolution and mechanical behavior of Al-Al2O3 nanocomposites were studied. The composites can retain high strength at elevated temperature and thermal soaking has practically no detrimental effect on strength. Although the ductility of the composite remains quite low, there was substantial evidence for high localized plasticity. The strengthening mechanisms of the composite include: Orowan strengthening, grain size strengthening and forest strengthening. Finally, (open full item for complete abstract)

Committee: Dr. Vijay Vasudevan (Advisor) Subjects: Engineering, Materials Science

Master of Science (M.S.), University of Dayton, 2012, Chemical Engineering

Recent advances in the science of nanoparticle synthesis have resulted in new core-shell nanoparticles displaying novel, unique, and potentially valuable properties for their use in propellants, fuels, and explosives. This research was conducted in support of the Propulsion Directorate of the Air Force Research Laboratory aimed at the development of functional reactive nanoparticles as fuel additives for improved thermal stability. In this work, oxidation of highly reactive zero-valent iron nanoparticles coated to prevent agglomeration and early reaction was studied as a novel approach to remove oxygen from the fuels. The particles were synthesized using sonochemistry, a well-established technique to self assemble core-shell nanoparticles, where the solution of pentacarbonyl Fe(CO)5 in dodecane was sonciated in the presence of an encapsulating compound, or shell material, to produce core-shell nanoparticles (CSNPs). The nanoparticles were stable at the temperatures below 120°C; at elevated temperatures, the shell material allows oxygen to permeate and react with the iron core depleting the oxygen from solution. It was observed that altering the structure of the shell material significantly influences the temperature-controlled oxidation of CSNPs over a range from 130°C to 188°C. This thesis investigates various shell material parameters including chain length, structural perturbation, and functional group to protect the iron core from oxidation at low temperatures and enable temperature-controlled oxidation of the iron core at higher temperatures. The impact of shell material parameters on CSNP solubility, particle diameter and temperature-controlled oxidation are investigated and reported.

Committee: Kevin Myers D. Sc., P.E. (Committee Chair); Guliants Elena Ph.D. (Advisor); Klosterman Donald Ph.D. (Committee Member); Gold Scott Ph.D. (Committee Member) Subjects: Chemical Engineering; Chemistry; Engineering; Materials Science; Nanoscience; Nanotechnology; Polymer Chemistry

Doctor of Philosophy, Case Western Reserve University, 2020, Biomedical Engineering

Glioblastoma multiforme (GBM) is resilient to the current standard of care treatment of surgical resection followed by concurrent radiotherapy and temozolomide (TMZ) chemotherapy. GBM patient responses are poor and variable, resulting in more than 90% tumor recurrence and grim survival. The high mortality of GBM is attributed to its invasive peripheral growth, partially intact blood-brain barrier (BBB), regions of hypoxia, and high cellular heterogeneity that includes brain tumor initiating cells (BTICs) and immunosuppressive cells. These features of GBM work together to restrict the delivery of drugs throughout the tumor, suppress immune recognition of tumor cells, and facilitate tumor progression. Nanoparticles are well-suited to address limitations associated with the treatment of GBM by enhancing drug delivery to the tumor and reducing side effects. The overall objective of the work in this dissertation is to develop systemically administered nanoparticles that overcome barriers to drug distribution and cellular heterogeneity in GBM to improve therapeutic responses. In murine GBM models, the effective delivery of Doxorubicin (DOX) chemotherapy, BTIC inhibitor, and immune-stimulating agonists were evaluated using two distinct mesoporous silica nanoparticles (MSNs): 1) the Fe@MSN particle and 2) the immuno-MSN particle. First, drug release from the Fe@MSN particle was triggered using an external radiofrequency (RF) field to enhance the distribution of DOX and/or BTIC inhibitor across the partially intact BBB and into the tumor interstitium. The effective delivery of drugs facilitated by Fe@MSN particles translated into suppressed GBM growth, depleted stem-like cell phenotypes in hypoxic regions, and prolonged or cancer-free survival. Second, towards further improving GBM treatment strategies, the immuno-MSN particle delivered immune-stimulating agonists to dysfunctional immune cells in GBM to reverse the effects of immunosuppression. Immuno-MSN particles facilitat (open full item for complete abstract)

Committee: Efstathios Karathanasis Ph.D. (Advisor); Agata Exner Ph.D. (Advisor); Dominique Durand Ph.D. (Committee Chair); Jennifer Yu M.D., Ph.D. (Committee Member) Subjects: Biomedical Engineering; Immunology

Master of Sciences (Engineering), Case Western Reserve University, 2017, Biomedical Engineering

Platinum resistance in ovarian cancer is the major determinant of disease prognosis. Resistance can first appear at the onset of disease or develop in platinum-sensitive (PS) disease in response to platinum-based chemotherapy. Due to poor response to alternative therapies, there is an urgent clinical need for a new avenue towards treatment of platinum-resistant (PR) ovarian cancer. Improved delivery systems may circumvent such resistant mechanisms and accelerate translation of existing drugs. In this work, I present a novel platform, tobacco mosaic virus (TMV), as a nanocarrier for cisplatin for treatment of PR ovarian cancer. A reliable method for preparation of the TMV-cisplatin conjugate (TMV-cisPt) was optimized and the cisplatin release was characterized. Efficient uptake in cancer cells in vitro was observed within 15 hours, and TMV-cisPt demonstrated superior cytotoxicity in PS and PR cancer cells when compared to free cisplatin. The cytotoxicity in PR cells and overall lower effective dosage requirement makes TMV-cisPt a potentially powerful system for improved ovarian cancer treatment.

Committee: Nicole Steinmetz Ph.D. (Committee Chair); Horst von Recum Ph.D. (Committee Member); Analisa DiFeo Ph.D. (Committee Member); Sourabh Shukla Ph.D. (Committee Member) Subjects: Biomedical Engineering; Biomedical Research; Medicine; Molecular Chemistry; Nanoscience; Nanotechnology; Oncology; Pharmaceuticals; Therapy; Virology

Master of Science (M.S.), University of Dayton, 2016, Electrical Engineering

Microbubbles are increasingly playing an important role in medicine and environmental waste management. In medicine, microbubbles coated with nanoparticles are being used for directed drug and gene delivery. In water treatment, microbubbles can trap nano-sized contaminants which can then be removed. Microbubbles can be used to remove unwanted nanoparticles from the bloodstream. Precise manipulation of microbubbles with and without nanoparticles is essential to achieve effective drug and gene delivery and waste cleanup. With these applications in mind, in this research, optical manipulation of microbubbles, and microbubbles coated with metallic nanoparticles, is investigated, both theoretically and experimentally. First, an equivalent force model on a microbubble by a focused optical beam is developed, starting from the force on a single induced dipole. This is extended to the case of microbubbles coated with metallic nanoparticles. Theoretical predictions are compared with experimental results. A focused laser beam, introduced in the vicinity of microbubbles of different sizes, attracts the microbubbles. The average velocities of these microbubbles can be related to the force imparted by the laser beam. Laser steering of the microbubbles is also experimentally demonstrated. It is shown that nanoparticles have a negligible effect on the manipulation of nanoparticle-surrounded microbubbles.

Committee: Partha Banerjee (Advisor); Joseph Haus (Committee Member); John Loomis (Committee Member); Donald Kessler (Committee Member) Subjects: Electromagnetics; Nanotechnology

Master of Science (M.S.), University of Dayton, 2015, Bioengineering

Due to their distinctive physicochemical properties, nanoparticles (NPs) have proven to be extremely advantageous for product and application development, but are capable of inducing detrimental outcomes in biological systems. Standard in vitro methodologies are currently the primary means for evaluating NP safety, as vast quantities of particles exist that require appraisal. Here, we developed an enhanced in vitro model that retains the advantages of cell culture, but introduces the key physiological variables of accurate biological fluid and dynamic flow. As NP behavior and subsequent bioresponses are highly dependent upon their surroundings, this developed microenvironment provides a more relevant system to evaluate responses following NP exposure. In this study, the microenvironment is comprised of the A549 lung cell model, artificial alveolar fluid, and dynamic flow at realistic rates; to mimic a NP inhalation exposure. Significant modulations were identified to silver and gold NP characteristics and the nano-cellular interface as a function of particle surface chemistry, fluid composition, and flow condition. More importantly, several of these modifications were dependent on multiple variables, indicating that these responses were previously unidentifiable in a standard cellular environment. Taken together, this study demonstrates that to fully elucidate the behavior and evaluate the safety of NPs, these assessments need to be carried out in a more complex and physiologically relevant cellular exposure model.

Committee: Kristen Comfort Ph.D. (Advisor); Donald Comfort Ph.D. (Committee Member); Saber Hussain Ph.D. (Committee Member); Jayne Robinson Ph.D. (Committee Member) Subjects: Biology; Biomedical Engineering; Engineering; Materials Science

Doctor of Philosophy, University of Akron, 2015, Polymer Science

Synthetic routes to 1-functionalized 4-vinylbenzocyclobutenes were developed with cyano, ester, amide and acetoxy 1-functional groups. The synthesis of a high molecular weight diblock quaterpolymer (i.e. two block, with two monomers in each block), where the blocks were highly immiscible (hydrocarbon / aliphatic fluorocarbon) and each contained a thermal crosslinker with a distinct curing temperature range, i.e. a “low” temperature crosslinker and a “high” temperature crosslinker by sequential polymerization using controlled radical polymerization was investigated. The synthesis of the desired diblock quaterpolymer was difficult or impossible due to radical chain transfer to 1-ethoxybenzocylcobutene. Fast chain-transfer to 1-ethoxybenzocyclobutene caused the polymerization to be inefficient and poorly controlled. Using a combination of ATRP and post-polymerization functionalization via the nucleophilic aromatic substitution of poly(pentafluorostyrene), a modular route to a strongly phase segregating benzocyclobutene functional diblock quaterpolymer was established. A linear diblock quaterpolymer was collapsed in two steps under pseudo-high dilution conditions into an amphiphilic single chain nanoparticle. Characterization of the soft organic particles by GPC, 1H- and 19F-NMR spectroscopy, atomic force microscopy, and transmission electron microscopy confirmed that they were single-chain particles. As part of a plan to possibly prepare the desired strongly phase segregating diblock copolymers by polymer-polymer conjugation using copper catalyzed azide-alkyne cycloaddition, the ATRP of styrene initiated from the popular alkyne functional initiator, prop-2-yn-1-yl 2-brom-2-methylpropanoate (PBiB), was systematically investigated. Using polymerization studies of PBiB a non-degenerative chain coupling side reaction was shown to be occurring. By repeating this study with similar protected alkyne functional ATRP initiators the side reaction was shown to be occurring due to (open full item for complete abstract)

Committee: Coleen Pugh Dr. (Advisor); Stephen Cheng Dr. (Committee Member); Chrys Wesdemiotis Dr. (Committee Member); Sadhan Jana Dr. (Committee Member) Subjects: Chemistry; Nanotechnology; Polymer Chemistry; Polymers

Master of Science (MS), Wright State University, 2015, Microbiology and Immunology

Dengue is an emerging hemorrhagic fever virus and widely considered the most important arbovirus in the world. The CDC and the World Health Organization estimates Dengue virus (DENV) infects 50-400 million people annually in the tropical and subtropical regions of the world. More than 500 thousand of these will develop severe infection and approximately 22 thousand will lead to death. Dengue virus (DENV) is a positive-sense RNA virus that exists in 4 antigenic serotypes. An immunological phenomenon called antibody-dependent enhancement (ADE) leaves a DENV victim vulnerable to increased risk of subsequent infections. Secondary infections with DENV are known to increase in severity from Dengue Fever (DF) to Dengue Hemorrhagic Fever (DHF) or Dengue Shock Syndrome (DSS). Currently, no vaccines or treatments are approved for DENV infections. Unsuccessful vaccine trials may open the door for non-traditional treatments such as silver nanoparticles. Silver nanoparticles (AgNP) are known to inhibit viral replication of numerous viruses but have never before been tested for inhibition of DENV. For the first time, this research presents reductions in DENV2 binding to Vero and RAW cells following pretreatment with AgNPs (6-10 nm, 8-25 µg/mL) and enhanced cell viability. These results suggest that similarly to other viruses, DENV infection can be inhibited at the first stage of the virus replication cycle, binding & entry.

Committee: Nancy Bigley Ph.D (Committee Chair); Ioana Pavel-Sizemore Ph.D (Committee Member); Courtney Sulentic Ph.D (Committee Member) Subjects: Immunology; Microbiology; Nanoscience; Nanotechnology; Pharmacology; Public Health; Toxicology; Virology

Doctor of Philosophy, University of Toledo, 2013, Chemistry

Two-dimensional self-assemblies of plasmonic nanoparticles (NPs) could one day become a useful technology for mankind as it has a potential to produce desirable structures with various patterning and ordering that is difficult to achieve by the top-down approach. Furthermore, these patterned and ordered structures of NPs have been known to display interesting optoelectronic properties. While applications using self-assemblies of plasmonic NPs seem promising, the fundamental forces that govern the evolution of these structures are not fully understood yet. Interesting similarities between the interfacial NP self-assembly and epitaxial growth exist despite a number of differences such as diffusion, desorption, coalescence, and ordering. The goal of this dissertation is to determine to what extent established submonolayer epitaxy theories can be applied to modeling interfacial NP self-assembly, and thereby develop new tools for understanding NP-NP interactions and self-assembly. Different sizes of 1-dodecanethiol (DDT) capped Au NPs were used to study the submonolayer growth behavior of NP islands. However, for the study, synthesizing DDT Au NPs > 8 nm by a conventional method was a challenge. To solve this synthesis problem, large NPs were synthesized in water and a phase transfer-based method was developed and used. While solving this synthesis problem, we developed general guidelines for NP phase transfer and determined that successful phase transfer only depended on three key surfactant parameters: bulkiness, length, and ability to get onto the interface. Furthermore, we also shed light on the mechanistic details of NP phase transfer into the organic medium. The experimental results for the submonolayer growth study such as NP island size distribution (ISD), capture zone distribution (CZD), percolation threshold, diffusion, and flux were compared and contrasted with the known epitaxy theories. It was found that islands were compact and circular at low covera (open full item for complete abstract)

Committee: Terry Bigioni PhD (Advisor) Subjects: Chemistry

Doctor of Philosophy, The Ohio State University, 2010, Integrated Biomedical Science Graduate Program

Nanoparticles are particles with at least 1 dimension less than 100 nm in size. The risks and consequences of acute and chronic nanoparticle exposure have not yet been adequately evaluated. Additionally, nanoparticle manufacturing plants are becoming more prevalent around the world. Therfore, there is cause for concern regarding the effects of nanoparticle related occupational hazards and also incidental nanoparticle exposure to the general public. This communication sought to further investigate nanoparticle/cell interactions, ensuing toxicity and cellular responses within biological systems. Three model nanoparticles were synthesized: quantum dots (QDs), modified carbon nanoparticles (CNPs) and a zeolite substrate containing silver nanoparticles. QDs were chosen to model mechanisms of nanoparticle internalization and compartmentalization. It was found that QDs interact with scavenger receptors, and enter cells via a clathrin coated pit mediated pathway. The kinetics of QD internalization was established; QDs were found to associate with macrophage cell membranes within 2.5 minutes, and are confined to lysosomes 9 minutes after exposure. QDs were found to be approximately 9 nm in size and aggregated when subjected to acidic conditions. Cadmium ions were found to leach from the core at low pH. Macrophages exposed to quantities 20 times greater than needed for imaging were found to induce TNF-α secretion and cytotoxicity, via apoptosis. To understand how the surface functional groups on nanoparticles drives inflammation and cytotoxicity, CNPs were modified with iron species, benzo(a)pyrene or ozone. Experiments utilizing primary human monocyte-derived macrophages revealed large variability in individual cell responses, ranging from increases in cytokines including TNF-α, to upregulation of complement factors. Carbon nanoparticles were added to cultures of murine macrophages and those modified with iron or B(a)P had little proinflammatory response. However, treating (open full item for complete abstract)

Committee: W. James Waldman Ph.D. (Advisor); Prabir Dutta Ph.D. (Committee Member); Susheela Tridandapani Ph.D. (Committee Member); Marshall Williams Ph.D. (Committee Member) Subjects: Nanoscience

Master of Science, The Ohio State University, 2009, Chemical Engineering

Manipulation of nanoparticles is an upcoming field with potential applications in nanofabrication, nanomanufacturing and biomedical sensors and devices. Thus far mainly mechanical methods have been used to “remove” or “deposit” nanoparticles on different surfaces with little or no control over the specificity of the particles .The use of additional control factors in manipulation of nanoparticles can serve as an attractive strategy to manipulate nanoparticles and even biomolecules in a highly specific manner. In this work we employ a new concept based on exploiting the surface charge of nanoparticles for vertical nanomanipulation method. By use of electric fields applied to a hybrid-conductive AFM cantilever (i.e. backside of cantilever is conductive but main body of cantilever and probe tip is non-conductive) we demonstrate how Au nanoparticles can be removed or lifted-off from a non-conducting surface based on their surface charge and mass. We envisage that this novel technique of using controllable electrostatic forces can be scaled up to manipulate large number of nanoparticles in parallel by use of multi-cantilever arrays or for manipulating and sorting biomolecules with specific charges and masses.

Committee: James Lee (Advisor); Gunjan Agarwal (Advisor) Subjects: Chemical Engineering

Doctor of Philosophy, The Ohio State University, 2004, Chemical Engineering

Industry estimates suggest that approximately 40% of lipophilic drug candidates fail due to solubility and formulation stability issues, prompting significant research activity in advanced lipophile delivery technologies. Solid lipid nanoparticle technology represents a promising new approach to lipophile drug delivery. Despite numerous research studies demonstrating improved therapeutic drug profiles, the commercialization of solid lipid nanoparticle technology remains limited. Physical instability and drug burst release have undermined performance while commercialization has been impeded by the lack of a large-scale, economically efficient production process. Research has been conducted with the objective of advancing solid lipid nanoparticle production technology. Formulation and process effects on solid lipid nanoparticle size distribution, stability, drug loading, and drug release have been investigated, culminating in a novel solid lipid nanoparticle synthesis approach based on electrohydrodynamic aerosolization. Utilizing a high-shear homogenization technique, effects of mixing speed, mixing time, and material concentrations were investigated using an experimental design approach. Experimentation showed stearic acid as the optimal lipid, sodium taurocholate as optimal cosurfactant, a 3:1 lecithin to sodium taurocholate ratio provided optimum performance, and mixing time and speed were inversely related to nanoparticle size and polydispersity. Beta-carotene was successfully incorporated into stearic acid nanoparticles. Beta-carotene entrapment efficiency was shown to have a maximum of 80 % with a mean of 40 %. Entrapment efficiency decreased with increasing Beta-carotene concentration. Beta-carotene was retained in the nanoparticles for one month, the maximum time period examined. A maximum Beta-carotene concentration of 0.39 mg/ml was obtained in the nanoparticle suspension. An electrohydrodynamic aerosolization device was designed and constructed for making (open full item for complete abstract)

Committee: James Rathman (Advisor) Subjects:

Doctor of Philosophy, Case Western Reserve University, 2012, Chemical Engineering

Controlling the diameter, length, and crystalline structure of semiconductor nanowires (s-NWs) during synthesis is essential for their envisioned technological applications. Among the various growth parameters, the seed particle plays a critical role in determining the final structure of s-NWs. However, metal seed particles are typically less than 5 nm in size and obtaining well-defined nanoparticles (NPs) in terms of their size, composition, and morphology remains a significant synthetic challenge. In this dissertation, we present several different approaches in the gas and liquid phase for the preparation of metal NPs that can ultimately be used for the growth of high quality s-NWs. In one approach, an atmospheric-pressure microplasma is used to dissociate organometallic precursors and produce clean, surfactant-free metal NPs in the gas phase. Combining vapor precursors at different ratios in the microplasma allows multimetallic NPs of tunable composition to be generated. The availability of a wide range of metal and alloyed NPs addresses an important problem in Si nanowire synthesis where metals such as Au create a deep level impurity. A particularly novel aspect of this thesis work is the first studies of shaped seed particles for nanowire nucleation and growth. Shaped Au particles are synthesized in the liquid phase by an established technique that relies on surfactant directed growth. These particles are then used to grow InAs NWs. We find that shaped Au particles enhance the nucleation/growth by increasing the apparent growth rate of InAs NWs by a factor of two as compared to the more typical spherical Au particles. In addition, we find that the shape of the seed particles is retained after growth. These studies suggest that the generally accepted vapor-liquid-solid (VLS) growth mechanism is not widely applicable, particularly in the case of shaped particles where the initial morphology is found to influence the nanowire nucleation/growth kinetics. Overall, o (open full item for complete abstract)

Committee: R. Mohan Sankaran phD (Committee Chair); Donald Feke phD (Committee Member); Xuan Gao phD (Committee Member); Chung-Chiun Liu phD (Committee Member) Subjects: Chemical Engineering; Materials Science; Nanotechnology

Master of Science (MS), Wright State University, 2013, Pharmacology and Toxicology

Gold nanoparticles (GNPs) possess unique physicochemical properties that may facilitate entry into the central nervous system (CNS) where they may act therapeutically. There is little information on biodistribution or inflammatory effects of GNPs in specific brain regions. Brain Localization and neuroinflammatory response to citrate-capped spherical GNP (10 nm) was determined 24 hours after intravenous (IV) injection in male C57Bl mice. A known inflammogen, lipopolysaccharide (LPS, 2 mg kg-1, SC), was tested as a positive control supplement. Aggregation of GNPs was measured using various Phosphate-Buffered Saline (PBS) concentrations (10, 1, 0.1, 0.01 X) to determine the optimal buffer concentration to maintain GNP solubility. 0.01 X PBS was used in all studies, since it produced the least amount of GNP aggregation. The next experiment verified entry of GNPs into the CNS. Mice were injected IV (200 µg mL-1 10 nm GNP in 0.01 X PBS) via the tail vein. After 24 hours mice were euthanized (with 130 mg ml-1 Euthasol), and perfused transcardially (with 2% glutaraldehyde and 2% paraformaldehyde), then brains were removed. GNP concentrations were measured using inductively coupled plasma mass spectrometry in whole brain homogenates. To specifically localize accumulation of GNPs in brain, septum, caudate, hippocampus, hypothalamus, cortex, frontal cortex, and spinal cord regions were micro dissected. Hypothalamus, hippocampus, and septum had the highest GNP levels (6.7, 6.2, and 4.6 µg Au g-1 tissue respectively). To evaluate brain inflammation, we used q-PCR analysis of frozen brain regions for study of pro-inflammatory mediators, Leukemia inhibitory factor (LIF), CC chemokine ligand 2 (CCL2) and Interleukine-1 ß (IL-1ß). GNPs did not affect cytokine/chemokine expression in cortex, frontal cortex or hippocampus. LPS (positive control), as expected, caused a marked (100-fold) increase in the same cytokines. Results show that GNPs enter brain and concen (open full item for complete abstract)

Committee: Mariana Morris Ph.D. (Advisor); Saber M. Hussain Ph.D. (Advisor); Ioana Pavel Sizemore Ph.D. (Committee Member) Subjects: Biomedical Research; Environmental Science; Health Sciences; Medicine; Nanoscience; Nanotechnology; Neurobiology; Neurosciences; Pharmacology; Toxicology

Doctor of Philosophy (PhD), Ohio University, 2024, Chemical Engineering (Engineering and Technology)

Molecular dynamics simulations and enhanced sampling techniques were employed to investigate adsorption behavior of surfactants at aqueous (metal-water and oil-water) interfaces. Key findings include: (a) Surfactants exhibit a strong affinity for metallic nanoparticles (MNPs), with a tendency of the alkyl tails to wrap around the MNPs. (b) The polar head of surfactants preferentially adsorbs onto the low-coordinated sites on MNPs, while the surfactant tails show no significant preference to adsorb on different MNP facets. (c) Surfactants with longer tails have a higher tendency to aggregate with themselves upon adsorption onto MNPs. (d) On a partially surfactant-covered planar metal-water interfaces, surfactant micelles preferentially adsorb onto bare metal patches. In contrast, on a fully surfactant-covered metal surface, adsorption is primarily driven by hydrophobic interactions, leading to the formation of a hemispherical configuration. (e) Surfactant micelles encounter a free energy barrier to adsorption on metal surfaces, regardless of the extent of surface coverage. (f) At oil-water interfaces with linear oil molecules, surfactants aggregate at the interface along with the oil molecules that align parallel to the orientation of the surfactants' alkyl tail. (g) In the presence of aromatic oil, linear surfactants and linear oils do not form a structured interface layer. (h) The interfacial tension at the oil-water interface decreases with increasing surfactant concentration.

Committee: Sumit Sharma (Advisor) Subjects: Chemical Engineering; Engineering

Doctor of Philosophy (Ph.D.), University of Dayton, 2024, Electro-Optics

This dissertation explores advanced techniques in nanofabrication and super-resolution imaging, focusing on the use of laser-induced transfer methods and fiber-coupled photonic nanojet (PNJ). The research demonstrates both numerically and experimentally the potential of microsphere-fiber PNJ lenses in achieving super-resolution imaging. Key findings highlight the successful excitation and imaging of quantum dots, emphasizing the method's precision in locating single quantum dots and achieving high-resolution imaging. First, we introduce the mechanisms and applications of several laser-induced nanoparticle transfer techniques. The investigation highlighted the differences and advantages of methods such as laser ablation in liquid (LAL), laser-induced forward transfer (LIFT), and the novel opto-thermal mechanical (OTM) approach. Each method's unique benefits and limitations were examined, with a particular focus on the OTM method due to its simplicity, cost-effectiveness, and versatility in transferring various types of nanoparticles (NPs). The OTM method was demonstrated to efficiently transfer NPs from a soft substrate to a receiver substrate using a continuous wave (CW) laser, offering a low-cost alternative to more complex and expensive femtosecond laser systems. In Chapter 3, the study investigates the release probability of gold nanoparticles (AuNPs) from various substrates under CW laser illumination. The research reveals that plasma cleaning of the substrate, although common, reduces the release probability due to increased particle adhesion. Additionally, the study finds that the mechanical properties of the substrate significantly influence the release probability, with more flexible substrates facilitating easier release of NPs. These insights are crucial for optimizing nanoparticle transfer technology for various applications. Chapter 4 extends the investigation to the sorting of AuNPs from polymethyl methacrylate (PMMA) substrates. The (open full item for complete abstract)

Committee: Imad Agha (Committee Chair); Chenglong Zhao (Advisor); Partha Banerjee (Committee Member); Erick Vasquez (Committee Member) Subjects: Optics; Physics

Master of Science, The Ohio State University, 2024, Animal Sciences

Salmonellosis continues to be one of the major public health concerns worldwide causing a gastrointestinal disease. Poultry meat and eggs are recognised as one of the major sources of Salmonella food poisoning in humans. Our study evaluated the protective efficacy of mannose-conjugated chitosan-nanoparticle (mChitosan-NP) based oral subunit vaccine consisting of outer membrane proteins and flagella of Salmonella Enteritidis against Salmonella colonization in the intestines of broilers by incorporating two known mucosal adjuvants, c-di-GMP (stimulator of interferon gene agonist) and whole cell lysate (WCL) of Mycobacterium smegmatis. We try to identify the optimal dose of c-di-GMP and WCL adjuvants by using three different amounts (2.5µg, 10µg and 50µg/dose) in vivo to potentiate the efficacy of Salmonella subunit vaccine formulation. In vitro analysis revealed that mChitosan-NP Salmonella vaccine and mChitosan-NP adjuvant formulations were carrying high positive charge (Zeta potential +20-25mV), size 235-260nm, and polydispersity index 0.35-0.52, conducive for in vivo studies. Subsequently, the vaccine-adjuvant formulations were evaluated for efficacy in vivo in broiler chickens by challenging with Salmonella Enteritidis. Our data showed that mChitosan (OMP+FLA)/FLA-NP WCL 10µg/dose formulation reduced over 0.5 log10 reduction of challenge bacterial load comparable to a commercial live vaccine at both day post challenge 4 and 10. The systemic and mucosal antibody responses were found superior in adjuvanted mChitosan-NP Salmonella vaccine groups. Additionally, most of the vaccine groups had an increased frequency of B cells compared to mock group at day post-challenge 4, associated with upregulation of TGF-β mRNA at day post-challenge 10. Overall, mChitosan (OMP+FLA)/FLA-NP WCL 10 µg/dose and mChitosan (OMP+FLA)/FLA-NP GMP 50µg/dose performed well in inducing immune responses and efficacy.

Committee: Renukaradhya Gourapura (Advisor); Liesa Bielke (Committee Member); Gireesh Rajashekara (Committee Member) Subjects: Animal Sciences

Master of Sciences (Engineering), Case Western Reserve University, 2024, Materials Science and Engineering

Aerosol jet printing (AJP) offers a unique solution to fabrication challenges for microelectronic devices due to its microscopic feature resolution, rapid prototyping capabilities, and ability to print on curved surfaces. However, AJP is challenged by a complex set of interrelated process parameters which must be carefully adjusted to achieve desired print properties. A series of studies were conducted to investigate the effects of AJP parameters on properties of silver nanoparticle ink flexible electronics, and to define an optimized set of parameters to achieve desired performance metrics. Specimens were characterized via optical microscopy, profilometry, electrical testing, static bend testing, and focused ion beam sectioning. It was found that silver nanoparticle ink retained chemical and particle size properties over a period of ~25 weeks. The effects of sintering parameters were investigated and it was determined that 175 °C marks a threshold sintering temperature below which prints did not conduct, but above, print conductance increased and microstructure showed densification and grain growth. A 65°C platen temperature was found to mitigate both spreading and excessive drying of ink. The effects of individual AJP process parameters on deposition thickness and conductance were evaluated. Finally, an orthogonal array optimization study was conducted to arrive upon a set of optimized printing parameters including aerosol and sheath gas flow, atomizer voltage, print speed, and platen temperature. Findings can be applicable to future works seeking to hasten the adaptation of aerosol jet printing to specific applications.

Committee: Janet Gbur (Committee Chair); James McGuffin-Cawley (Committee Member); John Lewandowski (Committee Member) Subjects: Biomedical Engineering; Electrical Engineering; Materials Science; Nanotechnology