Doctor of Philosophy, University of Akron, 2024, Polymer Science

Polymer-based coacervates can be prepared from a large variety of compositions. This provides versatility to coacervates as a material platform, but can also make them difficult to characterize, especially when other molecules or biologics are used in the same solution. The Joy lab has previously developed a platform to make thermoresponsive coacervating polyesters in a modular fashion. This allows us to make incremental changes to the coacervate structure and thus better observe how the structure affects the properties in various applications. In this work, we look at coacervates for hemostatic materials for non-compressible torso hemorrhage, and as sustained release drug delivery vehicles for colchicine release. Through a variety of experimental methods, our goal is to link structural changes in the coacervating polyester to the performance of the coacervate. The performance of our hemostatic coacervate was evaluated using clotting time tests, hemolysis tests, and rheology to determine how our materials interact with blood components. The trend in this data was further confirmed with in vivo mouse model studies which showed that the coacervates can perform well as hemostatic materials, and that the in vitro studies can effectively screen materials. We have also shown that amines in our coacervates are not effective and contrary to expectations and literature may increase bleeding times. To better predict coacervate properties on drug release, we employ NMR techniques such as STD and DOSY to better understand the strength of interactions between the coacervate and drug. The final drug release study confirms our NMR findings, and while the NMR techniques are not easily quantifiable, they do show an excellent relative predictability which can also be used to screen materials for an application. Ultimately, the tools employed for understanding coacervate performance enhance our understanding of their behavior in applications such as hemostasis and sustained (open full item for complete abstract)

Master of Science (M.S.), University of Dayton, 2023, Chemistry

Rare earth elements are found in relative ubiquity within the earth's crust and have a multitude of application to both everyday life and military defense. On the periodic table, rare earth elements consist of all 15 lanthanides, along with scandium and yttrium. These elements have a wide variety of application, spanning from private and public sector applications, all the way to military defense, thus making them highly desirable metals for eventual utilization. Current methods of rare earth element extraction and purification involve environmentally harmful processes, leading to North America's decision to not mine for rare earth elements within its territories. This decision has created a distinct lack of self-sufficiency in rare earth element production, currently resulting in a complete reliance of rare earth element imports from other countries, namely China. Due to the current processes of rare earth element extraction and purification posing large detriment to environmental stability along with a decrease in U.S. autonomy, determination of new, safer routes of rare earth element processing is of utmost priority. Specific proteins are known to bind metal ions, which has provided the scientific foundation for a protein-based extraction and purification method targeting rare earth elements. Previous research has identified a protein which is known to bind lanthanides, providing a high potential prospect for the solution to this problem. The protein of interest, named lanmodulin (LanM), contains four regions, denoted as EF hands, with three of which being involved in lanthanide binding. Building upon the previously mentioned solution is a thioredoxin protein found in the extremophile Pyrococcus furiosus. P. furiosus thioredoxin has shown the ability to stably accept newly introduced peptide sequences within its native amino acid sequence. The area of insertion possesses closely located cysteine residues which show p (open full item for complete abstract)

Master of Science (MS), Ohio University, 2023, Chemical Engineering (Engineering and Technology)

Phenolic-coal composites are a potential class of thermosetting composites that could offer enhanced thermal stability due to the similarity in aromatic macromolecular structures of the filler and polymer. Evaluating the curing kinetics of the composite can provide insight into the dynamics of bond formation in this composite during heat curing. This study employed Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA) to investigate the thermal properties and curing kinetics of phenolic resin and coal mixtures. The cured phenolic-coal composite samples were characterized using Fourier transform infrared spectroscopy (FTIR), to evaluate the interaction between coal filler and the polymer network and correlate coal structure and thermal behavior. The two ranks of coal studied were sub-bituminous coal (Powder River Basin) and bituminous coal (Itmann) at 10% and 40% weight content filler weight percentages. From the TGA, 60% Phenolic-PRB mix (Pmix) had the highest weight loss at 11-12%, while the 60% Phenolic-Itmann (Imix) records the least as 6%. DSC Isoconversional analyses indicated 60% Phenolic-PRB mix had the highest activation energy: 142±8 kJ/mol, while the 60% Phenolic- Itmann mix yielded the lowest range of activation energy values: 85±5 kJ/mol. In comparison, the pure phenolic resin has activation energies in the range of 128 – 135 kJ/mol. The difference in curing activation energy and post-cured vibrational spectroscopy between the composite systems could be attributed to more reactive functional end groups present in the PRB coal. The higher level of interaction observed in the sub-bituminous coal and phenolic mix confirms an enhanced polymeric behavior. Overall, the results from this study provide a basis for the fabrication of phenolic-coal thermoset composites tailored for different applications through modified end properties of cured phenolic resins based on the choice of coal ranks as fillers.

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

Working towards polymer sustainability is one of the key considerations in solving plastic pollution. Currently, thermosets and composites fabricated with the biobased seed oil polymer matrix have constraints of lower reactivity and overall mechanical strength. In this research, we tried to overcome this challenge by functionalization of seed oils (linseed and soybean oil). The reactivity of the conventional seed oils was increased by norbornylization technique. The functionalized seed oils were also epoxidized later and fabricated to thermosets and composites via both non-epoxide and epoxide curing routes. Next, thermally treated biomass sorghum fillers were incorporated into the system for increasing biobased content coupled with weight savings, cost-effectiveness, and better interface adhesion and mechanical properties. The recyclability of such thermosets was also investigated in lieu of the dynamic sulfur bonds incorporated via the curing agent. Finally, natural fiber-reinforced “green” composites were also fabricated and studied. Second, complex tire particles were subjected to abiotic weathering, and their degradation intermediates were investigated and quantified. Further, samples from roadside soil soils were collected, analyzed, and quantified to understand the tire additives prevailing for longer times in the environment. Thus the second part of the dissertation created a knowledge database on sustainable product development by concentrating on polymer degradation and common tire leachates in the environment.

Master of Science in Chemistry, Youngstown State University, 2023, Department of Biological Sciences and Chemistry

The enzyme β-galactosidase plays a role in the hydrolysis of lactose to galactose and glucose. Depending on the source, β-galactosidases can also carry out transglycosylation. This research was aimed at the biochemical characterization of β-galactosidase from Enterobacter sp. YSU. The enzyme is within the family of glycoside hydrolases. The Enterobacter sp. YSU β-galactosidase was overexpressed in E. coli. Subsequently, it was isolated using ammonium sulfate precipitation and a Q-Sepharose ion-exchange column. The single polypeptide chain protein contains 1056 amino acids with a molecular weight of 120 kDa. An in-gel activity test using 4-methylumbelliferyl-β-D-galactopyranoside established that the protein is active in its dimeric form. Dissociation of β-galactosidase into monomers in the presence of detergents like SDS results in the loss of enzymatic activity. The enzyme shows its optimal activity at pH 7.4 and a temperature of 40 °C. It has a limited substrate specificity of o-nitrophenyl-β-D-galactopyranoside (o-NPGal) and lactose. The catalytic parameters of the enzyme for o-NPGal were determined: KM is 0.3 mM, and kcat is 146 s-1. With respect to lactose, KM is 22 mM, and kcat is 3.86×103 min-1. Galactose competitively suppresses β-galactosidase activity, whereas glucose uncompetitively inhibits the enzyme. The enzymatic activity of β-galactosidase was affected by the presence of Mg2+ but not other divalent ions like calcium, zinc, or copper. Dimethyl sulfoxide caused a notable decrease in the activity of β-galactosidase while 2-mercaptoethanol had no effect on the activity of the enzyme. The β-galactosidase from Enterobacter sp. YSU showed a similar KM for lactose with most β-galactosidases isolated from other organisms but a higher kcat, and, therefore, there is a need to explore its applications in the hydrolysis of lactose.

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

Although impressive progress has been made to reduce the burden of heart disease, the illness remains the leading cause of death in the world. Notably, many types of persistent heart injury can cause pathological remodeling of the heart and progression to heart failure. The overall goal of my dissertation is to dissect novel molecular pathways responsible for such transition, since targeting them therapeutically presents an exciting opportunity to slow down heart remodeling and improve survival. While transcriptional regulators of progression to heart failure have been studied extensively, the importance of post-transcriptional regulation, such as chemical modification of messenger RNA, has been overlooked. Recent critical studies from our group and others demonstrated that methylation of mRNA in position N6 of adenosines (m6A) was essential for the heart's ability to adapt to stress, but the downstream regulators of this mechanism have remained elusive. Moreover, the field lacked a clear understanding of which cardiac m6A targets are most relevant and how they are regulated. After methylation, m6A-modified mRNAs are recognized by specific mRNA-binding proteins belonging to the YTH domain family (YTHDF), of which YTHDF1 and YTHDF2 are two key members expressed in the heart. In my work, I examine their specific contributions to the regulation of cardiomyocyte biology and their mechanistic effects on the distinct cardiac mRNA transcripts. First, I investigate the role of YTH N6-Methyladenosine RNA Binding Protein 2 (YTHDF2) in the heart using an inducible loss-of-function mouse model. I find that YTHDF2 protein is elevated in the failing mouse hearts and is essential for maintenance of cardiac homeostasis. Loss of YTHDF2 drives cardiac hypertrophy, fibrosis, and dysfunction in mice in the absence of any apparent stress. Furthermore, I detect that the proteome of YTHDF2-null cardiomyocytes is significantly remodeled, corroborating the importance of YTHDF2 in the re (open full item for complete abstract)

Doctor of Philosophy, Case Western Reserve University, 2023, Systems Biology and Bioinformatics

Recently, novel and unrecognized endogenous metabolites have been found to impact the risk of CVD not related to established risk factors (residual risk), including metabolites produced by gut microbes. Discovery platforms including metabolomics and metagenomics have identified new biomarkers associated with residual risk, but these platforms' usefulness is limited by the available methods of data analysis. This thesis aims to develop models of gut microbial metabolism using metagenomic data and new methods to identify unseparated structural isomers in metabolomics data. The gut microbial metabolism of trimethylamine-N-oxide, a metabolite associated with residual CVD risk, is used as a model system to develop predictive models of metabolism based on metagenomic information. An integrated analysis of metabolomics, metagenomics, and several other data types to predict circulating trimethylamine-N-oxide levels shows that while gut microbes play an essential role in trimethylamine-N-oxide synthesis, community composition does not quantitatively predict metabolism well enough to predict clinical risk. Analytical methods are developed to detect and identify structural isomers in metabolomics data. Two structural isomers, the terminal metabolites of niacin metabolism, are detected in human serum and characterized. Multiple clinical studies show these niacin metabolites are associated with residual CVD risk, and animal models show N1-methyl-4-pyridone-3-carboxamide (4PY) enhances vascular inflammation and thrombosis potential. Thus, new microbial and endogenous targets for therapy have been proposed, and new analytical methods have been introduced that may enable further study of residual CVD risk.

Master of Sciences, Case Western Reserve University, 0, EECS - Computer and Information Sciences

The ability to accurately predict molecular properties hinges on the quality of the molecular representations. Two common ways to depict molecules are through graphs or SMILES sequences. While Graph Neural Networks (GNNs) are often used for graphs, Transformer-encoder based architectures are typically used for SMILES sequences. However, few studies have explored the potential of combining these modalities and models. Current approaches for combining modalities often rely on basic methods like dot products for information integration. Inspired by recent progress in multimodal learning, we propose a more sophisticated approach that effectively combines the strengths of both modalities through cross-attention.

Master of Science, University of Akron, 2023, Polymer Science

The concept of “locked degradability” can address the trade-off between polymer degradability and stability by mechanophore installation. However, the limited mechanical activation due to uneven force distribution on polymers will inevitably lead to incomplete degradation. To overcome the limitation, we envision that self-immolative polymers (SIPs), which depolymerize spontaneously upon cleavage of the end group or backbone, can be used to amplify the mechanochemical response from an incorporated mechanophore. Here, a poly(7-phenyl-2,6-dimethylquinone methide) with a chain-centered [4.2.0] bicyclooctene (BCOE) mechanophore is designed and synthesized. Upon mechanochemical activation, the force-induced lactonization of BCOE is anticipated to trigger end-to-end depolymerization of the SIP backbone from the centered mechanophore to both chain ends.

Doctor of Philosophy, The Ohio State University, 2023, Molecular, Cellular and Developmental Biology

Triple negative breast cancer (TNBC) is an aggressive subtype of breast cancer that lacks expression of estrogen, progesterone, and human epidermal growth factor 2 receptors. TNBC is associated with an aggressive phenotype, poor prognosis, and limited treatment options. To date, the genetic drivers of TNBC pathogenesis are unknown. However, enlarged nucleoli, increased ribosome biogenesis and genetic alterations of positive and negative regulators of protein translation are widely observed in TNBC. To better understand the biology of TNBC and identify potential therapeutic targets, we have developed novel auxin inducible degron system to study the function of Nucleolin (NCL), a very abundant nucleolar protein involved in ribosomal biogenesis and nucleolar organization. Using this system, we observed that NCL is essential for proper cell division and prevention of tetraploidy formation via cytokinetic failure, a process in which cancer cells replicate their DNA without undergoing a physical division originating two distinct daughter cells. These findings confirm that NCL is a promising target for the treatment of TNBC, as inhibiting its function could potentially halt the proliferation of cancer cells. Overall, we show here how the use of the auxin inducible degron system provides unique insights into the role of NCL in TNBC.

Doctor of Philosophy, The Ohio State University, 2022, Chemistry

Numerous biological processes are carried out by the detection and interaction of small organic molecules, which assemble to form larger macrostructures. In Nature these processes are highly controlled, as small deformities can have deadly implications. Amino acids, peptides, nucleic acids, and proteins arrange with remarkable specificity into distinct structures that adapt, reorganize, and interact with their surroundings to enable the biological functions that characterize life. To truly duplicate the complexity, specificity, and operation of natural systems, however, it is essential to comprehend and design synthetic building blocks with controllable assembly properties and interactions. As an approach for creating responsive and adaptive materials, the self-assembly of organic peptide-based molecules into nanostructures was examined in the following studies. It is hoped that the advancements reported here in pH-controllable self-assembly, pathway control, and hierarchical structures can be further used to create nanomaterials for biomedical and optoelectronic applications.

Master of Science in Engineering, University of Akron, 2022, Civil Engineering

Cyanobacteria can produce cyanotoxins such as microcystin, saxitoxin, and anatoxin-a. These toxins are harmful to humans and other animals. This project focused on the removal efficiency of saxitoxin and anatoxin-a alone, as well as in the presence of microcystin-LR, by either powdered activated carbon (PAC) or chlorine. Furthermore, removal efficiency of these toxins by PAC was also determined in the presence of added active cyanobacterial cells in source water. PAC experiments were performed using distilled water and source water from the City of Akron Drinking Water Treatment Plant, located in northeast Ohio. pH had a significant impact on PAC results. Saxitoxin showed increased removal at higher pH levels in both distilled and source water. For instance, at pH 9 the removal was 48% in distilled water and 46-76% in source water, whereas it was 0-21% at pH 6 in distilled water and 23-47% in source water. Conversely, anatoxin-a showed increased removal at lower pH levels in distilled water, with 30-37% removal at pH 6 compared to 10-26% at pH 9 in distilled water. However, anatoxin-a removal increased at higher pH in source water with microcystin-LR added. For example, there was 31% removal at pH 6 compared to 65% and 59% removal at pH 7and 9, respectively. Microcystin-LR, when combined with either toxin, showed increased removal at higher pH levels in source water. pH 6 resulted in 9-45% removal and pH 9 resulted in 54-91% removal of microcystin-LR. Furthermore, the initial concentration of saxitoxin was a major factor, with the larger concentration (1.6 μg/L) resulting in 39% more removal in distilled water. On the other hand, in source water, the smaller STX concentration (0.3 μg/L) had 30% more removal. Finally, for PAC, the addition of cyanobacterial cells did not affect saxitoxin removal, however microcystin-LR removal decreased, with at least 14% reduction in removal efficiency across all pH levels. Chlorine experiments were performe (open full item for complete abstract)

Doctor of Philosophy, Case Western Reserve University, 0, Macromolecular Science and Engineering

Gene therapy is a highly promising disease treatment and prevention strategy through addition, inhibition, editing, or functional replacement of a gene, aiming to address the root cause of a disease. One critical issue in gene therapy is effective delivery of the therapeutic DNA into target cells through a viral or non-viral vector. About 70 % of vectors in clinical trials are recombinant viral vectors. The commonly used viral vectors, such as lentivirus and rAAV, are highly efficient in carrying DNA into many cell types and enable long-term expression of the cargo gene. However, viral vectors are of limited gene carrying capacities and very difficult and extremely costly to produce in therapeutic quantities, and they induce immune responses and often carry long-term cancer risks. These serious caveats associated with viral vectors are largely absent for non-viral vectors. However, non-viral vectors have their own shortcomings, one of which is the very poor cell entry by naked non-viral DNA vectors, necessitating the assistance of a DNA delivery agent. My research focuses on developing effective and adjustable polyethylenimine (PEI)-based DNA delivery agents for in vitro and validating their performance in vivo for future applications in gene therapy. PEIs are inexpensive and have shown good DNA delivery capacities in vitro. I first utilized GFP reporter plasmid DNAs and muscular and neuronal cell lines to identify the most promising PEI forms, then I subjected the select PEIs to systematic optimizations using the same cell culture systems. Finally, I applied the optimized PEIs, in comparison with a popular commercial DNA delivery agent, to deliver a few therapeutic genes carried on naked plasmid DNA vectors into cultured cells in vitro or into muscle or brain tissues in mice. The results show that the optimized PEIs are highly effective and significantly superior to the commercial reagent, especially in in vivo experiments, demonstrating the huge potential of our o (open full item for complete abstract)

Doctor of Philosophy, The Ohio State University, 2021, Chemistry

Host-guest chemistry is an expanding field within supramolecular chemistry, filling voids created by the need for novel ways to manipulate small molecules – such as removing pollutants or delivering drugs. The field is defined by study of the specific interactions between two or more molecules or ions and how they can be controlled. While there are many cavitands that can potentially be exploited in host-guest chemistry, it is their utility as applications that make the field ripe for advancement. A few such cavitands that are of interest to the Badjic group include a family of benzocyclotrimers known as baskets. These baskets have been used to sequester nerve-agent simulants and bind anti-cancer pharmaceuticals. To study these applications efficiently, copious amounts of basket is required and, therefore, an efficient synthesis is required. Past syntheses have led to minor amounts of syn small basket with long lag times and significant selectivity problems. Here we report the development of a stereoselective synthesis of small basket to both increase scalability and overall yield. To achieve this, a synthesis consisting of three key steps–including a stereoselective Diels-Alder reaction, a neighboring-group-assisted bromination, and a selective elimination–was utilized to create bromo-monomer 2.12 and bromo/tin-monomer 2.6. These monomers were then used in a copper catalyzed Stille-like reaction to create basket in increased quantities. With the ability to synthesize sufficient amounts of small basket, we turned our attention to synthesizing more complex poly-differentiated baskets. We utilize a stepwise coupling of three distinct monomers followed by aromatization to create these baskets. Both Stille and Suzuki cross-couplings were used to build the cavitands. Once an effective strategy was developed, we created a tBu-Me-Et ester basket syn-5.23 and naphthalene-benzene-anthracene basket syn-5.26; both are inherently chiral. Using this coupling strategy we also c (open full item for complete abstract)

Doctor of Philosophy, The Ohio State University, 2021, Comparative and Veterinary Medicine

Avian pathogenic E. coli (APEC), an extra-intestinal pathogenic E. coli (ExPEC), is one of the most common bacterial pathogens affecting poultry, including broilers, layers, breeders, turkeys and many other avian species. It causes high morbidity and mortality (up to 20%), decrease in production and increase in condemnation of carcasses (up to 43%) during slaughter, thus resulting in substantial economic losses to the poultry industry worldwide. Recent reports have suggested APEC as a source of human extra-intestinal infections, including urinary tract infections and sometimes meningitis. Further, APEC is also considered as a source of antibiotic resistance genes (ARGs) to human pathogens. Therefore, APEC is a pathogen of significant importance to both animal and human health. Currently, antibiotics are commonly used to control APEC infections; however, the increasing emergence of resistance to antibiotics and FDA (Food and Drug Administration) restrictions on using antibiotics in food-producing animals necessitate the development of new and effective antibacterials that can circumvent the resistance problem. Antibacterials targeting the outer membrane (OM) of bacteria can evade the problem of resistance in Gram-negative bacteria such as APEC. To this end, we discovered and evaluated small molecule (SM) growth inhibitors (GIs) and antimicrobial peptides (AMPs) affecting OM of APEC. We uncovered their antibacterial targets in the OM of APEC and assessed their impact on gut microbiome. We further demonstrated the potential of GIs as adjuvants to current antibiotics, including one of the last-resort antibiotics, colistin. A total of 11 GIs (GI1 – GI11) with bactericidal activity against APEC were identified through high throughput screening of pre-selected enriched small molecule library. Eight GIs that were effective and showed low toxicity in vitro in cultured epithelial and macrophage cells, red blood cells, and in vivo in wax moth (Galleria mellonella) larva mode (open full item for complete abstract)

Doctor of Philosophy, University of Akron, 2021, Polymer Science

Wound dressings play a pivotal role in providing favorable wound healing outcomes. Active dressings which incorporate bioactive agents such as anti-inflammatory drugs, antimicrobial compounds or peptides and proteins can help to alleviate patient pain and reduce healing times. This is especially true for diabetic ulcers, which are wounds that are stuck in the inflammatory stage of wound healing and are often associated with bacterial infection. This work describes the development of wound dressings capable of improving healing outcomes. To do so, a series of functional polyesters derived from a modular N-substituted diol monomer platform were synthesized. Wound dressings comprising these polyesters were fabricated using the 3D printing and electrospinning techniques. Dyes serving as model drug compounds were released from electrospun dressings to show the ability of these dressings to deliver drugs. The two fabrication techniques were used to create dressings comprised of varying polyester compositions. An in vivo acute wound rat model showed that despite their varying compositions and thread sizes, none of them were detrimental to normal healing processes. Electrospun dressings showed broad spectrum antimicrobial activity in an acute infected wound mouse model when an antimicrobial poly(ester urethane) was incorporated. Finally, 3D printed scaffolds were conjugated with peptides capable of recruiting keratinocytes and fibroblasts in an attempt to improve healing outcomes in an acute wound rat model. These studies seek to guide future researchers in the design and implementation of active wound dressings, especially by showing the utility of functionality within those dressing systems.

Master of Science in Chemistry, Youngstown State University, 2020, Department of Chemistry

This thesis deals with an attempted “one-pot”azidation of carbohydrate secondary alcohols using arylsulfonyl azides. It also deals with the investigation of the reaction mechanism through which the attempted azidation process takes place. The results showed that the attempted azidation did not occur. Instead, the reactions led to the isolation of different sulfonate ester intermediates. A combination of steric (and stereoelectronic) problems were suspected to be the probable cause shutting down the substitution pathway.

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

Solute-vacancy interactions and grain boundary structure and dynamics in an MgO crystal are investigated through molecular dynamics simulations. For the first time using molecular dynamics simulations, the binding entropy and enthalpy are determined directly for a solute-vacancy system in a single crystal of magnesium oxide, with a binding entropy of 13±5 (95% CI) J/mol K. The binding energy is also shown as a function of pressure. The method of (Sastry, Debenedetti, Stillinger, et al.) to quantify structure in glasses is applied to simulations of MgO grain boundary structures to identify equilibrium grain boundary structure and grain composition. The dynamical exchange of atoms within the grain boundary is demonstrated. The grain boundary diffusion coefficient is obtained as a function of temperature and pressure, and implications for grain boundary diffusion and transport through the inner earth are presented, with the result that the characteristic grain boundary diffusion length is constrained to be less than about 100 m for magnesium and oxygen at the core-mantle boundary. Finally, the transition between effective volume diffusion and effective grain boundary diffusion is obtained as a function of temperature and pressure.

Doctor of Philosophy, The Ohio State University, 2020, Chemistry

Self-assembling nanostructures provide a unique class of materials for uses in medicine, diagnostics, engineering and fabrications, and other `smart' systems. By exploring dynamic assemblies, research has brought forth insight into self-healing, biological machinery, and morphological changes induced through multiple stimuli. Within dynamic assembly is a subset called dissipative assembly, where a state of assembly is induced through constant energy input. Failure to adequately provide the system with such a `fuel' causes the system to revert back into a thermodynamically preferable state. This idea is far reaching, from energy storage to life itself and is deserving of more exploration. Herein, we have designed two such kinds of dynamic assemblies: one static and one dissipative. The former utilizes dithienylethene (DTE) bola-amphiphile derivatives capable of reversible photocyclization through exposure to UV or visible light respectively. UV light changes the rigidity of the monomers leading to 1D nanofibers from kinetically trapped aggregates with input from ultrasonication. Once uncyclized via visible light, the nanofibers revert to spherical micelles. These DTE-bolaamphiphiles show differing levels of photoisomerization dependent upon the solvent environment. Thus, we have developed a dynamic system that will reversibly change with additional energy but will remain in a kinetically trapped state until more energy is applied to cause further change/reversion. The latter dynamic assembly utilizes spiropyran (SP)- modified tetrapeptide derivatives in an acidic aqueous environment. Visible light causes the SP units to remain in a hydrophobic form, while thermal energy and acid causes an isomerization to a hydrophilic protonated merocyanine (MC) form. Thus, a competitive environment was designed where these tetrapeptides were held at elevated temperatures with an LED visible light source that could be turned on or off. While ON, the hydrophobic SP units caused (open full item for complete abstract)

Bachelor of Science (BS), Ohio University, 2020, Chemistry

Throughout the world, pollutants in water have become commonplace, largely as the result of human activities. Environmental organizations test waterways all over the United States for a wide array of polluting agents, from organic materials found in pesticides, to harmful bacteria, to heavy metals. The standard instrument used to measure the quantity of metals in water samples is an inductively coupled plasma spectroscopy. This specialized instrument requires extensive training and is expensive to purchase, operate, and maintain. As a result, it places a burden on the testing of water samples and can prohibit water from being tested in a timely manner. Therefore, there is a current need for a faster process to evaluate water samples. The overall objective of this study was to assess the viability of utilizing functionalized silver nanoparticles to economically determine the concentrations of cations, specifically barium and strontium ions, in contaminated water samples. The ligands on the nanoparticles selectively bind the ions, which induce a color change in the nanoparticles that is detectable by a UV-Vis spectrophotometer, a relatively cheap analytical instrument. Significant progress towards the practical application of functionalized nanoparticles with environmental samples was made. After the addition of high concentrations of barium and strontium ions, nanoparticle samples shifted color from yellow to pink, signifying the feasibility of bare-eyed detection. Creating samples with a range of ions from 1 mM to 100 mM, a rough detection range for barium and strontium ions were determined. Regression analysis indicated a strong trend between plasmonic resonance absorbance wavelengths and the concentrations of metal ions in water. With these findings, there are many avenues for future work. To name a few, different nanoparticles could be used, the possibility of interfering factors common in water samples should be investigated, and further data at dif (open full item for complete abstract)