PHD, Kent State University, 2024, College of Arts and Sciences / School of Biomedical Sciences

Wound healing is a very complex process requiring a well-orchestrated integration of multiple cellular and molecular events involving many players for antimicrobial activity and the promotion of new vascular formation. Acute wounds are healed by following the normal process of repair including inflammation, proliferation, and remodeling phases. If acute wounds fail to progress through the normal healing phases, it can develop into delayed healing or non-healing chronic wounds, particularly associated with the presence of bacterial biofilm (a community of bacteria encased in a protective matrix) and impaired angiogenesis. Conventional antibiotics frequently develop resistance and have limited efficacy against biofilm-associated wound infections. Approaches for promoting pro-angiogenic activity for wound healing have been relied on the use of bioactive molecules or growth factors, which have limitations in developing cost-effective treatment options. Additionally, thus far, each of the above aspects for antimicrobial and proangiogenic activities have been separately investigated to a great extent and an integrated approach to simultaneously addressing these three issues in a single drug delivery platform has yet to emerge. Wound scaffolds are biomaterial platforms designed to support tissue regeneration and enhance wound healing. In particular, nanoparticle-based scaffolds hold promise for treating chronic wounds due to their characteristics to exhibit higher reactivity due to high surface to volume ratio for improved cellular interactions, and easiness in surface functionalization, and controlled release of bioactive molecules. Additionally, their small size enables deep penetration into the wound bed. In this study, we propose to harness the unique characteristic of copper ion that can exhibit antibacterial and pro-angiogenic properties towards developing a cost-effective 33 scaffold for treating chronic wounds. Copper has emerged as an essenti (open full item for complete abstract)

Doctor of Philosophy, The Ohio State University, 2024, Electrical and Computer Engineering

An exciton is an electrically neutral quasiparticle that consists of an electron and a hole attracted to each other by the Coulombic force of attraction due to the opposite charge of the constituent pair. Exciton can form with the absorption of a photon into a material (insulator or semiconductor) as an intermediate state which can soon dissociate and produce photocarriers i.e., electron and hole under suitable condition. Normally a photon with above bandgap energy would get absorbed into any material of interest, but under an applied electric field a photon with below bandgap energy can be absorbed due to band bending as the wave function of the constituent electron and hole leak respectively from the Conduction Band and Valance Band into the forbidden region. This absorption process is known as the Franz-Keldysh (FK) effect. In Wide Bandgap Material (WBM)s such as Gallium Nitride (𝐺𝑎𝑁) and Beta-phase of Gallium Oxide (𝛽 − 𝐺𝑎2𝑂3) the FK effect is dominated by the formation and later dissociation of exciton. The below bandgap photon absorption via intermediate exciton state can be a process of general interest to explain the below bandgap photoresponsivity of the WBM under study. The understanding of exciton physics in this context can be utilized to engineer important applications such as to accurately detect and quantify the local electric field and the onset of breakdown behavior of the material which can help in designing Radio Frequency (RF) and power electronic devices with high reliability and stability. This dissertation looks at the excitonic physics of Wide Bandgap Materials i.e., 𝐺𝑎𝑁 and 𝛽 − 𝐺𝑎2𝑂3 with the objective to explain the experimentally observed photoresponsivity characteristics through eXciton Franz Keldysh (XFK) effect. Application of the exciton mediated below bandgap photon absorption physics in mapping out the electric field variation of 𝐺𝑎𝑁 p-n diode and 𝛽 − 𝐺𝑎2𝑂3 Schottky diode with applied external voltage are also d (open full item for complete abstract)

Doctor of Philosophy, The Ohio State University, 2024, Materials Science and Engineering

This dissertation presents biochemical sensing systems for wearable, implantable, and high-resolution chemical sensing applications. By integrating biorecognition elements, sensing interfaces, and wireless communication strategies, we aim to provide a low-cost, reliable, and highly accurate platform for real-time biochemical monitoring in clinical and experimental settings. We first demonstrate a wireless sensing system that is miniaturized, lightweight, and compatible with common biochemical sensing interfaces. Inspired by RF tuning circuits, our simple circuit design allows battery-free operation and accurate monitoring of multiple biomarkers. The modular design separates the inductive coupling unit and the electrochemical sensing interface, minimizing strain-induced changes and ensuring accurate recording. This system is compatible with common electrochemical sensing methods, including ion-sensitive membranes (ISM), aptamer-based sensors, and enzymatic interfaces. And allow for the detection of ions, neurotransmitters, and metabolites across different application scenarios. For instance, a "smart necklace" consists of glucose sensors, that are capable of wirelessly detecting sweat glucose during exercise. A wearable skin patch monitored cortisol levels in sweat showcases the functional adaptability for stress-related biomarker detection. Additionally, a miniaturized implant prototype illustrated the potential for continuous in vivo monitoring. Our work also introduces a portable vector network analyzer (pVNA) designed to overcome the size limitations of traditional VNAs. This research provides the design and working principle for a wearable reader, which allows for real-time monitoring of resonance frequency and Q factor of the inductive coupling wireless sensor. Furthermore, we introduce “NeuroThread”, a neurotransmitter-sensing platform that utilizes the cross-section of commercially available ultrathin microwires to serve as microelectrode. This cost (open full item for complete abstract)

Doctor of Philosophy, University of Akron, 2024, Chemical Engineering

Thermoplastic elastomers (TPE) are a set of materials with characteristics of elastomers and thermoplastics. There is an increasing demand for polymers to be processed into three dimensional porous constructs for tissue engineering. Aliphatic polyester-based, poly(butylene succinate-co-dilinoleic succinate) (PBS-DLS) and polyisobutylene-based, poly(alloocimene-b-isobutylene-b-alloocimene) thermoplastic elastomer copolymers and their development will be presented for end use as biomaterial-based therapies in this dissertation. Electrospun fibrous scaffolds are favored for tissue engineering for their micro-structured networks creating a high surface area to volume ratio and this high interconnected porosity. These properties help mimic natural tissue structure for better tissue integration and diffusion through the network. Applying thermoplastic elastomers as scaffolds offers materials whose material properties can be tailored for specific applications. This dissertation presents work to advance biodegradable aliphatic copolymers for tissue scaffolds, and polyisobutylene copolymers for drug delivery. Cardiac soft tissue regenerations strategies employ biodegradative copolymers for cell delivery. Completely bio-based and biodegradable PBS-DLS copolymers have shown great potential for coiled 3D scaffolds for cardiac applications. This dissertation presents the kinetics of a step enzymatic polycondensation of PBS-DLS copolymers with varying feed ratios. 1H NMR and SEC results found that hydrophobic soft segment DLS was incorporated into the hard segment PBS within the first 3 hours. After which, the pressure was increased during second stage and complete DLS incorporation and high Mn oligomers occurred between 24 and 48 hours. MALDI-ToF analysis showed that the lower molecular weight fractions cyclic formation of long PBS sequences are favored during early stages of reactions. Poly(styrene-b-isobutylene-b-styrene) is currently used as the coating on the Taxus coronary (open full item for complete abstract)

Master of Science, The Ohio State University, 2024, Chemistry

Layered transition metal chalcogenides have great potential for a variety of applications in electronics, energy harvesting, catalysis, and membrane technologies, owing to their distinctive textural and photoelectronic properties. Intercalation of organic molecules into the interlayer spaces of these compounds can result in profound changes in the physical and chemical properties and lead to the emergence of unique phenomena. In this study, we report on the intercalation of ammonium and organic amines into interlayer spaces of layered chalcogenides of the form K2Ni3S4 via ion-exchange reactions. This unique family of layered transition metal chalcogenides is comprised of anionic layered, honeycomb networks of perpendicularly oriented MS4 square planes, separated by alkali ions. The growth of thin crystallites of K2Ni3S4 was carried out using potassium sulfide flux. After exploring a variety of substitution reaction schemes, we find that ammonium cations and cationic organic amines can be readily exchanged with the alkali cations in aqueous solution using a combination of X-ray diffraction, X-ray fluorescence, infrared spectroscopy, thermogravimetric analysis, transmission electron microscopy, and scanning electron microscopy with energy dispersive spectroscopy. Overall, this work establishes an intriguing new family of hybrid organic-inorganic layered materials.

Master of Science (M.S.), University of Dayton, 2024, Chemical Engineering

There is a continuous thrust for cleaner and more sustainable alternatives for energy conversion with the increasing global energy demand. Among them, photovoltaics, specifically thin film solar cells are highly promising and are one of the fastest growing clean energy technologies in the United States. This research presents the synthesis and characterization of a set of novel multinary copper chalcogenide semiconductor nanocrystals (NCs), CuZn2ASxSe4-x consisting primarily of earth-abundant elements for applications in photovoltaic devices. A modified hot-injection method was used to synthesize these semiconductor NCs containing both S and Se chalcogens. The novelty of the new semiconductor NCs lies in the incorporation of multiple cations as well as two different chalcogen anions within the crystal lattice, which is an achievement from the materials synthesis aspect. The composition-controlled optical and photoluminescence properties of the CuZn2ASxSe4-x NCs were investigated via multi-modal material characterization including x-ray diffraction (XRD), ultraviolet-visible (UV-vis) spectroscopy, and photoluminescence spectroscopy (PL). The crystal structure, as determined from the XRD primarily consisted of the metastable wurtzite (P63mc) phase. The NCs exhibited direct band gap in the visible range that could be tuned both by varying the group III cation within the composition as well as the ratio of S/Se, based on the Tauc plot obtained from the UV-vis characterization. This work lays the groundwork for future investigations into the practical applications of copper chalcogenide NCs in solar energy conversion.

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

Cancer metastasis is a multistep cascade often associated with interactions between adhesion molecules expressed on the vascular endothelium and cognate ligands expressed on circulating tumor cells. E-selectin is a major adhesion molecule expressed on the endothelium, and there are numerous literature reports that interaction between E-selectin and E-selectin ligands can contribute to cancer metastasis. However, only a few E-selectin ligands have been identified on breast cancer cells. On the other hand, nucleolin has been reported to be involved in many diseases including cancer. Previously, cell surface nucleolin was identified as an L-selectin ligand under shear stress conditions for head and neck cancer cell lines, and exosomes from hematopoietic stem/progenitor cells have been reported to express E-selectin ligand activity. Therefore, it is hypothesized that breast cancer cells express cell surface nucleolin as an E-selectin ligand, and their exosomes express E-selectin ligand activity. The first aim is to determine if cell surface nucleolin acts as an E-selectin ligand on breast cancer cells. Using flow cytometry and immunofluorescence experiments, nucleolin is shown to be expressed on the surface of four common cell line models of breast cancer (BT-20, MDA-MB-468, MDA-MB-231 and Hs578t). Parallel plate flow chamber experiments show that cell surface nucleolin is a functional E-selectin ligand at a certain shear stress, and BT-20 and MDA-MB468 human breast cancer cells adhesively interact with endothelial E-selectin via cell surface 4 nucleolin under flow conditions. Furthermore, sialidase treatment experiments indicate BT-20 and MDA-MB-468 cell surface nucleolin is a sialidase-sensitive E-selectin ligand under shear flow. The second aim of this dissertation research is to determine if breast cancer exosomes express E-selectin ligand activity. Exosomes are small extracellular vesicles (40-150 nm in diameter) secreted b (open full item for complete abstract)

Doctor of Philosophy, The Ohio State University, 2024, Chemistry

Nature showcases many biological systems that assemble into complex hierarchical architectures with potential for maintaining structural stability and multifunctionality that are essential for the sustenance of life. More specifically, biological building blocks such as amino acids, peptides, proteins, nucleic acids, lipids, and photosynthetic pigments, etc. arrange with themselves or other building blocks with high specificity into well-defined structures that can interact and adapt in response to their environment to perform the biological functions. Inspired by nature, self-assembly of π-conjugated organic small molecule-based building blocks into artificial functional nanostructures has been exploited in different fields. To mimic the natural systems in terms of the multifunctionality, complexity, and specificity, it is critical to design and understand the supramolecular assembly of novel synthetic building blocks in a controlled way. As a powerful approach for developing functional materials, the self-assembly of amino acid appended organic small molecules was utilized in this study. The self-assembly of a novel synthetic building block comprised of four lysine appended NDI motifs attached to a central porphyrin via noncovalent interaction has been explored. The photophysical and morphological properties are characterized that could find a way for the potential applications in photodynamic therapy, energy transfer, and light harvesting. Additionally, supramolecular co-assembly techniques offer diverse ways to fabricate multicomponent heterostructures as multifunctional materials. However, when multiple monomeric components interact each other through noncovalent interactions, endless outcomes such as self-sorted, random, block, and alternating sequence, etc. can be generated depending on the reactivity or recognition of homo-homo or hetero-homo interactions. Therefore, controlling the sequence of multiple monomers in the multicomponent assemblies is critical (open full item for complete abstract)

Doctor of Philosophy, Case Western Reserve University, 2024, Biomedical Engineering

Ultrasound (US) is safe and low-cost relative to other imaging technologies, making it an increasingly popular diagnostic modality. US contrast is often limited by relatively low differences in acoustic impedance in the body, necessitating the use of contrast agents like microbubbles (MBs; ~1-10 µm diameter) which are intravenously injected and used to compensate for low contrast in conventional B-mode US imaging. The large size of MBs, however, limits their applications to the blood pool. In many diseases, including cancer, information beyond the blood pool is needed for diagnosis and staging. For instance, in many cancers (e.g. prostate, mammary, ovarian etc.), tumors are characterized by high vascular permeability and low lymphatic drainage, which increases the potential for enhanced permeability and retention (EPR) of macromolecules (~200 nm). When present, EPR leads to the tumor-localized accumulation of nano-agents. Nanobubbles (NBs) are new-age submicron bubble agents (100-500 nm diameter) capable of extravasation beyond the vascular network while providing enhanced US contrast similar to MBs. Recently, our group showed that active targeting of NBs to prostate specific membrane antigen (PSMA) rapidly and selectively enhances tumor accumulation and retention. These processes were visualized in real-time with clinical US. This project established NBs as a sensitive detection tool in the diagnosis of PSMA-positive prostate cancer due to localized NB accumulation, reduced diameter and higher number density (NBs per volume) of NBs compared to MBs of similar composition. Together, these points enable: 1) contrast visualization of small capillaries with higher fidelity, and 2) imaging of extravascular cellular targets reached via extravasation of NBs in leaky blood vessels while employing 3) a safe and widely accessible imaging modality. Together, contrast enhanced ultrasound (CEUS) using NBs (NB-CEUS) is a detection method with high biocompatibility and high safe (open full item for complete abstract)

Doctor of Philosophy (PhD), Wright State University, 2023, Electrical Engineering

Since their invention in 1958, Integrated Circuits (ICs) have become increasingly more complex, sophisticated, and useful. As a result, they have worked their way into every aspect of our lives, for example: personal electronic devices, wearable electronics, biomedical sensors, autonomous driving cars, military and defense applications, and artificial intelligence, to name some areas of applications. These examples represent both collectively, and sometimes individually, multi-trillion-dollar markets. However, further development of ICs has been predicted to encounter a performance bottleneck as the mainstream silicon industry, approaches its physical limits. The state-of-the-art of today's ICs technology will be soon below 3nm. At such a scale, the short channel effect and power consumption become the dominant factors impeding further development. To tackle the challenge, projected by the ITRS (International Technology Roadmap for Semiconductors) a thinner channel layer seems to be the most viable solution. This dissertation will discuss the feasibility of using 2D (two-dimensional) materials as the channel layer. The success of this work will lead to revolutionary breakthroughs by pushing silicon technology to the extreme physical limit. Starting from graphene in 2004, 2D materials have received a lot of attention associated with their distinct optical, electrical, magnetic, thermal, and mechanical properties. In the year 2010, IBM demonstrated a graphene-based field effect transistor with a cut-off frequency above 100 GHz. The major challenge of applying graphene in large-scale digital circuits is its lack of energy bandgap. Other than carbon, a variety of graphene-like 2D materials have been found in various material systems, like silicene, germanene, phosphorene, MoS2, WS2, MoSe2, HfS2, HfSe2, GaS, and InS, etc. Among all the 2D materials, silicene appears to be the most favored option due to its excellent compatibility with standard silicon technology. Simil (open full item for complete abstract)

Doctor of Philosophy (PhD), Ohio University, 2024, Physics and Astronomy (Arts and Sciences)

A nascent instrument called Synchrotron X-ray Scanning Tunneling Microscope (SXSTM), which challenges the limits of conventional X-ray absorption spectroscopy (XAS) methods by accessing elemental and chemical details of matter at the ultimate atomic limit, is employed in this dissertation to observe and investigate the magnetism at the ultimate atomic limit. First, a series of X-ray Magnetic Circular Dichroism (XMCD) signals deduced from near field XAS signatures in SXSTM tip channel are used to observe surface magnetism in Ni islands grown on Cu(111) while that of the sample channel is used to identify ensemble magnetism. We observe that the magnetic moments at the surface are enhanced compared to that of the sample. A comparative study also reveals that the magnetic moments of a magnetized sample are elevated compared to that of a nonmagnetized sample. In this work we establish the first ever detection of magnetism at the ultimate atomic limit by capturing the XMCD signature of an Eu atom caged in pcam ligands which are adsorbed on top of magnetized Ni islands on Cu(111), hence displaying magnetism due to a Van-Vleck like effect while coupling ferromagnetically to the host Ni layers. Differential conductance (dI/dV) measurements backed with theory demonstrate that the Eu3+ becomes magnetic by transitioning into a non-zero total angular moment (J>0). Dimer molecules are formed with a mixture of two different precursors containing Eu and Tb in this dissertation, using Ullmann reactions on Au(111) which exhibit different chirality and various types of clustering upon dimer formation, while sequences of near field XAS point spectra provide evidence towards dimers with different as well as similar rare earth (RE) atoms caged in the same dimer. They further reveal that both Eu and Tb are preserving their original +3 oxidation state in the dimers. We also report the first-ever radiograph of a single atom by means of X-ray images carried out at M5 edges of Eu (open full item for complete abstract)

Doctor of Philosophy, The Ohio State University, 2024, Biochemistry Program, Ohio State

This dissertation focuses on the development of Raman microscopy techniques to monitor nanoparticle uptake in cells. Chapter 1 introduces the importance of monitoring nanoparticle delivery for development of new therapeutic and sensing modalities. Nanoparticle characterization methods are then introduced, as these are important in determining nanoparticle properties and utility. Raman microscopy, the primary imaging technique used to monitor particle location in cells, is briefly described. Enhancement of Raman scattering (through either resonance of the laser with an electronic transition of the analyte or analyte adsorption to a plasmonic surface), are also briefly described, as these are critical to their respective applications in nanoparticle imaging. Chapter 2 focuses on Raman monitoring of lycopene-polysorbate 80 nanoparticles in cells. This research shows effective delivery of lycopene into cells. Raman imaging may be used to monitor the quantity, distribution, and isomerization of lycopene in cells. This information contributes to understanding both lycopene delivery to cells and the mechanism of action of lycopene for improving prostate cancer outcomes. Chapters 3 and 4 focus on monitoring gold nanoparticle delivery in cells. Chapter 3 discusses pH sensing methods for determining gold nanoparticle subcellular location. These methods are various data analysis approaches to interpreting the surface enhanced Raman scattering from 4-mercaptobenzoic acid to determine local pH in cells, aiming to infer nanoparticle endosomal escape from pH measurement. The pH method was complicated by the requirement of nanoparticle aggregation for detection, and a limited range of sensitivity of the reporter molecule to pH. Research then focused on spatially localizing every nanoparticle in a cell. Chapter 4 will describe the development of Raman microscopy-based single particle imaging, and a proof of concept in cells. The sensitivity and resolution achieved in this study ar (open full item for complete abstract)

Doctor of Philosophy, Case Western Reserve University, 2024, Macromolecular Science and Engineering

For high capacitance density multilayer ceramic capacitors, high dielectric constant and lead-free ceramic nanoparticles are highly desired. Lead-free barium titanate (BaTiO3 or BTO) nanocrystals (NCs) represent an important class of such nanodielectrics. In Chapter 1, we have reported a systematic investigation into the crystal structure-dielectric property relationship of combustion-made BaTiO3 nanocrystals. Our results reals that the “size effect” of the nanoparticles seemed not that simple. Although the X-ray photoelectron spectroscopy and high-resolution transmission electron microscopy could not identify the exact structural defects due to the technical difficulties of sample preparation, we resolved the contradictory phase assignment from XRD and Raman analysis and discussed the understanding that surface and bulk defects formed during synthesis affect the final crystal structures and thus dielectric properties of BTO nanocrystals with different sizes. The combustion-made BTO nanocrystals exhibited a low dielectric constant up to ~300, which is much lower than that (~1000) of the multi-domain BTO (001)-SC. In Chapter 2, we have introduced a theoretical deconvolution method for analyzing polarization-electric field (P-E) loops from the polymer/nanoparticle nanocomposites. We have prepared PVP/BTO nanocomposite films as PVP film with different volume fractions of BTO nanoparticles (20-40 vol%) at room temperature via spin-coating. Surprisingly, broad ferroelectric P-E loops for PVP/BTO60 nanocomposites were yielded when the volume fraction of BTO60 was above 30 vol%, even though neither the PVP matrix nor the BTO ceramic nanoparticle exhibits any intrinsic ferroelectricity. Using a theoretical deconvolution of the broad P-E loops based on the Langevin-type function, three contributions were identified. First, deformational polarization generated the linear dielectric constant of nanocomposites, from which the linear dielectric constant of BTO60 nanopartic (open full item for complete abstract)

Doctor of Philosophy, University of Akron, 2023, Polymer Science

Nanostructured hybrid materials can be formed using self-assembling side chains grafted to a polymer backbone. Small-angle X-ray and neutron scattering (SAXS & SANS) measurements on polyisobutylene graft copolymers with side chains containing β-alanine trimer have revealed that crystalline nanodomains form by self-assembly. Modifying the side chain chemistry allows one to tailor the β-alanine nanocrystal length from over 300nm down to approximately 10nm. The degree of crowding at the nanodomain interfaces impacts the temperature dependence of the microphase separation. Chemical variations in the side chains, such as removing C18 tails and adding C11 spacers between the backbone and β-alanine trimers have dramatic effects on nanocrystal size, domain spacings, order-disorder transition temperature and width of transition, crystal melting temperature, and bulk mechanical properties. The last chapter describes progress in defining the interface morphologies in blends modified with Interfacial Supramolecular Coupling Agents (ISCAs) containing β-alanine. Polyethylene (PE) and polypropylene (PP) constitute the majority of mixed plastic waste produced globally. In the approach studied, it is envisioned that a pair of ISCAs will populate the interfaces between PE-rich and PP-rich phases and anchor the phases together. From SAXS, SANS, Wide Angle X-ray Scattering (WAXS) and Atomic Force Microscopy (AFM) analysis it is evident that the presence of ISCAs alters the crystalline structure of the overall blend.

Master of Science (MS), Bowling Green State University, 2023, Physics

Over the past several decades, nanomaterials have undergone significant improvements and developments. Among these, infrared nanomaterials have potential applications in fiber optics communications, night vision, and sensing, with PbS nanomaterials standing out as a particularly promising option. In this work, we explored two distinct techniques to enhance the light-emitting efficiency of PbS nanosheets: organic ligand passivation and inorganic shell encapsulation. For the organic surface passivation, we utilized tributylphosphine as a ligand. Meanwhile, for inorganic passivation, we designed a core/shell structure using PbCl2. To achieve this inorganic core/shell structure, we pioneered a robust synthesis method capable of producing orange nanoplatelets. Notable, both strategies led to a substantial increase in the photoluminescence quantum yield. Such nanosheets with augmented quantum yield could be pivotal in the evolution of photonic devices, encompassing light-emitting diodes, solar cells, and lasers.

Master of Science in Materials Science and Engineering (MSMSE), Wright State University, 2023, Materials Science and Engineering

The persistent demand for flexible and wearable electronic components in healthcare, aerospace, media, and transit applications has led to a significant shift from traditional electronics processes to printed electronics. Printed electronics are anticipated to establish itself as the industry's dominant force due to their enhanced flexibility, rapid prototyping capabilities, and seamless integration with everyday objects. They are cost-effective and have the scalable option for large-scale production because additive manufacturing techniques are used. Among the various printing methods available, inkjet printing has recently gained popularity for printing electronics, especially capacitors that require precise and complex structures on different substrates. Inkjet printing relies on micro dispensing additive technology, where liquid phase materials are dispensed using the drop on demand (DOD) technique with conductive nanoparticle inks. Researchers have made several attempts to fabricate fully inkjet-printed composite capacitors and have discovered that the permittivity value of the composite increases compared to a polymer. This suggests that using composites as the dielectric material in a capacitor can potentially increase the capacitance value. However, despite the discussion on various composite dielectric materials, there is a scarcity of information on the use of BaTiO3/SU-8 dielectric materials for capacitor applications. To address this gap, the objective of this study is to formulate BaTiO3/SU-8 ink suitable for inkjet printing and develop a printing process for layered metal insulator metal (MIM) structures. The formulated BaTiO3/SU-8 ink is employed to print the dielectric material, while nano silver ink is used for the two electrodes, enabling the fabrication of the capacitor in a single step. The study takes into account volume and speed jetting parameters as well as waveform to achieve optimal and uniform liquid phase material inkjet printing on the s (open full item for complete abstract)

Doctor of Philosophy, University of Toledo, 2023, Chemistry

Monolayer-protected clusters (MPCs) are a class of metal-organic compounds that typically contain dozens of metal atoms yet retain their molecularity. The MPCs have two main structural components, the inner metallic core, and the outer ligand shell. Therefore, the modifications of these MPCs can be done by altering either the metal core or the outer protecting ligand shell through metal/ligand exchange reactions. Significant progress has been made toward understanding the transformational chemistry of gold MPCs through metal and ligand exchange reactions. But comparatively, only a little information is known on the transformational chemistry of silver MPCs so far. In this study, we used the all-silver M4Ag44(p-MBA)30 MPC as a model system to study post-synthetic ligand exchange reactions, where M is a mono-cationic counterion and p-MBA is para-mercaptobenzoic acid. Different para-substituted aryl thiols were used as heteroligands, varying both electronically and sterically. The fundamental investigations were focused on revealing the nature of these reactions, reaction extent, exchange sites and kinetics to gain mechanistic insights into the ligand exchange reactions. The product distributions of the ligand exchange process were monitored by electrospray ionization mass spectrometry (ESI-MS) and UV-vis spectroscopy. Using these techniques, we identified a few trends in ligand exchange on silver MPCs concerning the electronic and steric nature of the heteroligand. Our investigations revealed that the ligand exchange on silver MPCs is electrophilic in nature and the electronic structure of the ligand plays a strong role in the exchange compared to the steric effects. Also, product distributions of ligand exchange on silver MPCs were found to be random with no evidence of site specificity. The stabilities of M4Ag44(p-MBA)30-x (SR)x (SR are thiol ligands such as 4-bromothiophenol (4-BTP), 4-fluorothiophenol (4-FTP), benzenethiol (BT), 4-methylbenzethiol (4-MBT), 4 (open full item for complete abstract)

Doctor of Philosophy, The Ohio State University, 2023, Biomedical Engineering

Micro- and nanoscale technologies can be engineered to modulate the biochemical cues expressed by adipose tissue, thereby influencing their fate and reprogramming cascade. By leveraging these revolutionary platforms, regenerative therapies can be tailored to the unmet specific needs of patients, amplifying controlled tissue repair, wound healing, and immunomodulation. Adipose tissue-related abnormalities are characteristic of a disease state but engineering of in vitro or in vivo models can be an optimistic avenue to study, explore, and mitigate such irregularity. This could potentially be achieved by mimicking the surface energy and topography of the extracellular matrix (ECM). The presented research highlights promising micro/nanotechnology-based contrivances for augmenting adipose tissue-related cellular and reconstructive therapies. Micro/nanotechnology-based platforms hold immense, yet still untapped potential of adipose tissue-derived stem cells to advance personalized treatments. Thus, the technologies described here in the research and their future derivatives could usher in a new era of regenerative medicine by lending intelligent solutions for more effective patient outcomes. The first chapter therefore provides an overview of adipose tissues intricacies and how micro- and nanotechnology can empower our understanding of the same to perform in-situ cell transformation or develop biomaterials which could bolster cellular microenvironment. The second chapter introduces promising direct reprogramming of one cell to another cell type using implantable micro- and nano-channel based gene reprogramming therapy (TNT) device. Such a device offers cellular reprogramming with precision and can transform a fibroblast into brown adipose tissue. The third chapter focusses on a different route using injectable electrospun biopolymer for tissue reconstructive purposes. The last chapter brings a holistic viewpoint highlighting the potential of micro/nanotechnologies fo (open full item for complete abstract)

Doctor of Philosophy (PhD), Ohio University, 2023, Physics and Astronomy (Arts and Sciences)

For over several decades, research on plasmonics has been of great interest due to its applicability in many fields. The use of metallic nanoparticles to manipulate incident light allows the advancement of sensing, cloaking, heat transfer and chemical reactions. This dissertation presents the study of the light-matter interaction corresponding to a variety of nanostructures due to the excitation of plasmons. Included, is the computation of optical properties of single nanoparticles and periodic arrays of nanoparticles in the visible spectrum with the purpose of understanding and describing the different processes that occur due to the absorption of light. These processes include interband and intraband transitions and surface scattering, all of which occur from the absorption of light. The last process mentioned is of great interest in the generation of hot electrons, which could be capable of overcoming an energy barrier and get transferred to another materials. This transfer of hot electrons could be used to accelerate chemical processes like photocatalysis. Additionally, the optical properties of nanofluids containing nanobars are presented to manipulate the response to light in the infrared. The main objective is to block specific ranges of wavelengths by combining nanobars of different lengths. We additionally studied multiple materials to find a cheaper alternative to gold. The combination of theoretical and computational methods were used throughout this study and in some cases, they are complemented by experimental results in the literature. The final objective of this dissertation is to describe and propose novel methods and approaches to further understand the plasmonic response of these nanostructures.

Master of Science, Miami University, 2023, Mechanical and Manufacturing Engineering

Microorganisms, particularly flagellated bacteria, have inspired the development of microswimmers, which are microscale robots designed for fluid environments. They can be self-propelled or externally controlled and find applications in biomedicine, including drug delivery, biosensing, and microsurgery. At the microscale, where inertial forces are negligible, viscous forces become dominant, requiring specialized simulation methods. Molecular Dynamics (MD) simulations offer a suitable approach by representing complex systems as particle interactions and have been extensively used for studying various systems. In our research, we employ a 3D model of a swimmer-channel system, departing from previous 2D representations, to analyze the intricate dynamics between microswimmers and their fluidic environment. Our analysis provides valuable insights into microswimmer behavior and enables us to recommend optimal design strategies. Additionally, we utilize interaction networks as a Machine Learning technique to predict microswimmer behavior based on MD simulation results. This work paves the way for further advancements in the study and application of microswimmers, contributing to scientific progress in this field.