Master of Science in Polymer Engineering, University of Akron, 2013, Polymer Science

Poly(lactic acid) (PLA) is considered to be one of the most promising biodegradable materials in the family of aliphatic polyesters. PLA and its copolymers, such as poly(lactic acid)-co-(glycolic acid), are widely used as biomedical materials or alternatives to petrochemical-based polymers. PLA has the advantage that it is produced commercially by an efficient method at relatively low cost. However, there are some disadvantages to PLA. It is brittle and difficult to functionalize. Blending is an extremely promising approach to improve the properties of polymers. Blends may exhibit the physical and chemical properties of both individual polymers. The miscibility of the two polymers can be evaluated by the glass transition temperature (Tg) method. Different chemical properties, such as optimum hydrophilic/hydrophobic balance and the ability to act as a drug-carrier may be obtained by functionalization of our recently synthesized brominated PLA copolymers. Materials with good mechanical properties may be produced by blending functionalized PLA with high molecular weight commercialized PLA. This study investigates the miscibility of brominated PLA with high molecular weight PLA. The influence of different blends ratios, molecular weights of PLA and configurations of PLA on the miscibility is presented.

Committee: Coleen Pugh Dr. (Advisor); Li Jia Dr. (Committee Member) Subjects: Polymers

Doctor of Philosophy, University of Toledo, 2013, Biomedical Engineering

Current controlled release formulations has many drawbacks such as excess of initial burst release, low drug efficiency, non-degradability of the system and low reproducibility. The present project aims to offer an alternative by developing a technique to prepare uniform, biodegradable particles (~19 µm) that can sustainably release a drug for a specific period of time. Chitosan is a natural polysaccharide that has many characteristics to be used for biomedical applications. In the last two decades, there have been a considerable number of studies affirming that chitosan could be used for pharmaceutical applications. However, chitosan suffers from inherent weaknesses such as low mechanical stability and dissolution of the system in acidic media. In the present study, chitosan microparticles were prepared by emulsification process. The model drug chosen was acetylsalicylic acid as it is a small and challenging molecule. The maximum loading capacity obtained for the microparticles was approximately 96%. The parameters for the preparation of uniform particles with a narrow size distribution were identified in a triangular phase diagram. Moreover, chitosan particles were successfully coated with thin layers of poly lactic-co-glycolic acid (PLGA) and poly lactic acid (PLA). The performance of different layers was tested for in vitro drug release and degradation studies. Additionally, the degradability of the system was evaluated by measuring the weight loss of the system when exposed to enzyme and without enzyme. Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM) and inductively coupled plasma optical emission spectrometry (ICP-OES) were used to characterize the controlled release system. Additionally, the in vitro drug release was monitored by ultraviolet-visible spectrophotometry (UV-Vis) and liquid chromatography mass spectrometry (LC-MS). The results obtained from this project showed that it is pos (open full item for complete abstract)

Committee: Arunan Nadarajah PhD (Committee Chair) Subjects: Biomedical Engineering; Biomedical Research; Chemical Engineering; Materials Science

Doctor of Philosophy, The Ohio State University, 2022, Food Science and Technology

Waste streams from the food industry have been associated with severe environmental pollution and an economic burden for producers. The Food and Agricultural Organization from the United Nations has stated that one-third of the global food chain production ends up as food waste. The dairy and fish industry has significant roles in producing waste streams that threaten the ecosystem due to their high biological and chemical oxygen demand. The by-products from both industries have shown several complications for its proper treatment of disposal. Therefore, science-based approaches that can handle the treatment more efficiently or, otherwise, transform them to add value and include them as part of other foods. The increasing demand for acidified and fresh-like dairy products has made the handling of acid whey a disposal burden for this industry. Acid whey is the milk serum left after the removal of caseins after fermentation and acidification. On the other hand, the most valuable part of fisheries is the fillet that only represents 40-45% of a fish; this value means that more than 50% of this food chain becomes waste. However, both waste streams are considered nutrient-dense co-products with potential complementary nutritional advantages suitable for biotechnological technologies and valuable products' production. In this work, we hypothesized that under appropriate conditions, a semi-controlled fermentation of the mix of acid whey and minced fish waste can break down the complex proteins from fish; a close follows up to understand the microbiome and chemical changes would lead to a safe and nutritionally bioavailable product. To this end, the first objective was to find the optimum conditions and materials ratios that would deliver the best proteolysis, including the addition of a starter culture and a simple carbohydrate source. Additionally, the innate microbiota from the co-products and changes during the fermentation was closely monitored using 16S-v4 rRNA a (open full item for complete abstract)

Committee: Rafael Jimenez-Flores (Advisor) Subjects: Food Science

Master of Science, The Ohio State University, 2020, Food Science and Technology

Milk phospholipids (MPLs) are valuable dairy components known for various health benefits, like reducing gastrointestinal infections and supporting neurological development. They are used as functional ingredients for food application and human consumption. Meanwhile, lactic acid bacteria (LAB) are also associated with beneficial effects on human health. They are commonly used in fermented dairy products, and many of them are regarded as probiotics. The possibility of using MPLs and LAB as a combination has great potential benefit and has shown some synergistic effects on the delivery of both ingredients. Little is known about the direct impact of MPLs on LAB, which contributes to the determination of MPLs supplementation strategies and LAB culture selection. Our first objective was to test the influence of MPLs on the growth and cryotolerance of LAB in MRS and acid whey-based dairy (AW) media. We screened 134 strains in our collection and selected 13 LAB strains using 0.5% MPLs supplemented modified minimal medium (MM) and another 14 strains using the AW medium. The growth curves of those 13 LAB in MRS and 0.5% MPLs supplemented MRS media were compared. The cell viability counts and acidification ability of those 14 strains cultivated in AW and 0.5% MPLs supplemented acid whey-based (AWM) media were evaluated using the plate counting method and skim milk fermentation test before and after three cycles of freeze-thawing treatment. We hypothesized that the addition of MPLs would impact the growth of LAB differently in diverse media, and MPLs supplementation could modify the cryotolerance of LAB. Results indicated that the addition of 0.5% MPLs showed a strong inhibitory impact on the growth of LAB in the MRS medium while promoting the growth and enhancing the cryotolerance of LAB significantly in the AWM medium. The second objective was to investigate the adhesion or interaction between MPLs and LAB using the sucrose gradient centrifugation test and further analyze t (open full item for complete abstract)

Committee: Rafael Jimenez-Flores (Advisor); Ahmed Yousef (Committee Member); Zhongtang Yu (Committee Member) Subjects: Food Science

Master of Arts, The Ohio State University, 1915, Graduate School

Committee: Not Provided (Other) Subjects:

Master of Science, The Ohio State University, 1971, Graduate School

Committee: Not Provided (Other) Subjects:

Doctor of Philosophy, The Ohio State University, 2024, Food Science and Technology

This dissertation investigates the enzymatic parameters of a β-galactosidase derived from the probiotic candidate, Lactobacillus helveticus OSU-PECh-4A (Lb. helveticus), with a focus on its potential for galacto-oligosaccharide (GOS) production. β-galactosidase is a hydrolytic enzyme that catalyzes the breakdown of lactose into its simpler sugar, glucose, and galactose. Simultaneously with lactose hydrolysis and under specific conditions, β-galactosidase can also produce highly demanded prebiotics known as galacto-oligosaccharides (GOS). In this dissertation, a thermostable β-galactosidase from Lb. helveticus has been isolated through diafiltration and size-exclusion chromatography and characterized through enzymatic assay and differential scanning fluorimetry (DSF). The isolated enzyme consists of a heterodimer with a molecular mass of 110 kDa, with a small and large subunit of 36 kDa and 74 kDa, respectively. The Km and Vmax values for lactose hydrolysis were 29.87 ± 1.05 mM and 1.88 ± 0.02 μmol D-glucose released per min per mg of protein, respectively. The enzyme is stable under a wide range of pH and high temperatures in terms of activity (≥ 40 °C). Once characterized, the enzyme capacity to produce GOS was evaluated through a 2x2 factorial design using substrate concentration and temperature as variables. The GOS produced were quantified and identified using high-performance liquid chromatography coupled with a charged aerosol detector (HPLC-CAD) and liquid chromatography with electrospray ionization mass spectroscopy (LC-ESI-MS/MS), respectively. To provide a perspective of the many possible applications of the enzyme, the enzyme's capacity to use different sugar acceptors to produce fucose-containing GOS was also evaluated by comparison. A maximum GOS yield of 12% was obtained at an initial lactose concentration of 200 g/L under 45 °C for 12 h. The GOS mixture consisted of 82% GOS, from which 6'galactosyl-lactose (trisaccharide), lactulose (disaccharides) (open full item for complete abstract)

Committee: Rafael Jiménez-Flores (Advisor); Valente Álvarez (Committee Member); Monica Giusti (Committee Member); Osvaldo Campanella (Committee Member) Subjects: Food Science

Doctor of Philosophy in Clinical-Bioanalytical Chemistry, Cleveland State University, 2022, College of Sciences and Health Professions

Poly-l-lactic acid has been of great interest to the medical profession in recent years because of its biodegradability and biocompatibility. The biodegradation rate can be controlled by its crystallinity content. One method to modify its crystallinity content is by cold drawing. Raman spectroscopy is utilized to distinguish between the different crystalline content on the sample. However, a chemical imaging method is needed to characterize the polymer on the macro level. Chemical imaging using Raman spectroscopy is an important method of characterization that is non-invasive and non-destructive. The emphasis of my research has been to develop a method to characterize the crystalline content of poly-l-lactic acid using Raman chemical imaging and multivariate analysis to construct a robust image of the crystalline map. No Technique exists for this purpose. Multivariate analysis has been beneficial for reducing the time spent on finding correlations in a vast amount of data. Principal component analysis has been one of the most common methods for reducing the data dimensions to those that are the most responsible for the observed variation in the data. However, the method is scale variant and blends qualitative and quantitative information in a way that can render misleading results. Classical least squares has also been used in chemical imaging, but it requires substantial training data. In this document, we introduce a modified version of reduction of spectral images (ROSI), a multivariate analysis method that heavily modifies principal component analysis to reduce the amount of data while still prioritizing the minority pixel population on the image data to retain more of the analytically meaningful characters of the data. Preprocessing of the data is an important step to obtaining robust results and can involve multiple steps depending on the application. It often serves as an essential step for removing irrelevant information from the raw data. One important pr (open full item for complete abstract)

Committee: John Turner II (Advisor); Warren Boyd (Committee Member); Baochuan Guo (Committee Member); Xue-Long Sun (Committee Member); Petru Fodor (Committee Member) Subjects: Biomedical Engineering; Chemistry; Materials Science; Plastics

Doctor of Philosophy (PhD), Ohio University, 2023, Chemical Engineering (Engineering and Technology)

Nanofibers and nanocomposites are one method used to enhance the properties of existing polymers. Commercially produced, practical grade chitin from shrimp shells was processed using pulsed ultrasonication and then incorporated into the PLA matrix using a two-roll mill as composites. Composites of 1, 3, and 5 wt% chitin in PLA were analyzed by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and isoconversional kinetic analysis. Tensile and izod impact tests were done on injection molded test specimens for the same range of composites. Pure PLA samples were prepared in the same manner. Field emission electron microscopy (FESEM) of the chitin and PLA-ultrasonicated chitin composites showed that the nanostructured microfibrous chitin material incorporated into the composites retained much of its natural structure. In general, the thermal properties of the composites were similar to those of pure PLA. The melting point measured for the composites with DSC for the range of 0-5 wt% chitin-loading demonstrated a melting point decrease of 5°C, from 151.1 to 146.5°C. The glass transition temperature decreased from 52.6 to 47.3°C. The cold crystallization temperature decreased by 10°C from 109.9 to 99.9°C over the same range of chitin loading. The effective activation energy measured by isoconversional kinetic analysis using the Ozawa-Flynn-Wall model indicated a single step reaction consistent with the random bond scission process for all of the PLA and composite samples. The analysis was performed in air using TGA. Activation energies of 170 ± 11, 234 ± 12, 251 ± 11 kJ/mol were measured for 1, 3, and 5 wt% chitin in PLA, respectively. The value for PLA was 191 ± 9 kJ/mol consistent with published values. The increase in activation energy from 1 wt% to 5 wt% chitin loading is almost 50%. This is a dramatic increase in thermal stability, possibly due to the protection of PLA by a surface coating of chitin. The mechanical (open full item for complete abstract)

Committee: Marc Singer (Advisor); Rebecca Barlag (Committee Member); Jason Trembly (Committee Member); Martin Kordesch (Committee Member); John Staser (Committee Member); Monica Burdick (Committee Member) Subjects: Chemical Engineering; Plastics

Master of Science, The Ohio State University, 2021, Food Science and Technology

Lactic acid bacteria (LAB) are rarely found in single species in naturally occurring food fermentations such as yoghurt, kefir wine, etc. This is because synergistic microbial communities promote positive interactions between species thus promoting better growth, metabolite regulation, and antimicrobials production. These positive interactions can be facilitated by nutrient and metabolite exchange, changes in the extracellular environment (pH, ionic strength), quorum sensing, or the exchange of enzymes. In general, properties of LAB in monocultures have been extensively studied in different growth media, however, synthetic co-cultures are less explored and are gaining increasing research attention. Enzymatic activities such as proteolytic, lipolytic, and β-galactosidase can be correlated to nutrient exchange between LAB, flavor, and texture in food fermentations. Changes in these enzymatic and antimicrobial activities in co-cultures, and their impact on the growth of individual species remain unexplored. Here in this study, we present a comparison of growth of LAB in multiple co-cultures (consortia) over 20 h of growth, while also tracking the enzymatic and antimicrobial activities (bioactivities) of the co-cultures over time. Lactobacillus plantarum OSU-PECh-BB (Lp), Lactobacillus reuteri OSU-PECh-48 (Lr), and Pediococcus acidilactici OSU-PECh-3A (Pa) were chosen for this study and seven combinations were made from them (Lr, Lp, Pa, Lr-Lp, Lp-Pa, Lr-Pa, Lr-Lp-Pa). The growth of individual species was tracked in every combination using iv Real Time-qPCR and was compared across the combinations. Case of commensalism was observed between Lr and Lp, where Lp grew in higher counts with no impact on Lr. This result was attributed to the high proteolytic activity of Lr during the initial stages of growth. On the other hand, amensalism was observed between Lp and Pa, where Lp grew in significantly lower counts as compared to its monocu (open full item for complete abstract)

Committee: Rafael Jiménez-Flores (Advisor); Matthias Klein (Committee Member); Osvaldo Campanella (Committee Member) Subjects: Food Science; Microbiology; Molecular Biology

Master of Science, The Ohio State University, 2020, Food Science and Technology

Kefir is a fermented dairy beverage that has been shown to successfully treat recurrent Clostridioides difficile infection (CDI) when consumed in conjunction with antibiotic treatment. Unfortunately, kefir has limited patient acceptance due to its strong acidic and fermented flavors produced during fermentation. To improve the flavor of kefir, further processing could be utilized, such as high heat spray drying, which can reduce undesirable volatile organic compounds (VOCs). To protect live microorganisms from high heat, encapsulating agents may be added to the mixture. In this study, the effect of spray drying with and without an encapsulating agent on commercial kefir's water activity, moisture content, VOCs concentration, microbial viability and activity, microstructure, and sensory quality was analyzed. Kefir was spray dried in the pilot plant either without an encapsulating agent, with whey permeate, or with whey protein isolate. Water activity and moisture content of powder samples were obtained; volatile compounds concentration was measured using selected-ion flow-tube mass spectrometry (SIFT-MS); microbial viability was assessed by enumeration on selective media for Lactobacillus species and Lactococcus species, and bacteria were identified by 16S ribosomal DNA (rDNA) sequencing; microbial activity was assessed by inoculating kefir into milk and measuring change in pH over time; microstructure was examined using scanning electron microscopy (SEM) images, and sensory quality was determined by untrained panelists ranking samples and answering acceptability/likeability questions on kefir attributes. All three spray-dried kefir powder samples had water activity below 0.25 and water content below 5%, indicating high storage stability products. The total concentration for 29 VOCs in all spray-dried products was reduced significantly, with spray-dried kefir without encapsulating agent having the highest reduction of 61.2%, followed by kefir with whey permea (open full item for complete abstract)

Committee: Valente Alvarez (Advisor); Rafael Jimenez-Flores (Committee Member); Ahmed Yousef (Committee Member) Subjects: Food Science

Master of Science, The Ohio State University, 2019, Food Science and Technology

Buttermilk is rich in milk fat globule membrane (MFGM), which consist of a well-defined group of milk phospholipids (MP). MP play an important role in brain and nervous system development. However, intact MP are also known for its low absorption in the intestine when compared with glycerolipids. Lactic acid bacteria (LAB) is one of the most common bacteria used in dairy products. Many of the LAB are beneficial for health, improving gut function, and regulating immune response. Moreover, the metabolites: the lipases and proteases produced by them can hydrolysate lipids and proteins, which can lead to better absorption of nutrients. Studies showed that metabolites produced by LAB are associated with increased absorption of sphingomyelin and potentially all the MP. The hypothesis is that LAB with lipolytic activity resulting from buttermilk fermentation with MP enriched can increase the presence of enzymes that can modify phospholipid and produce phospholipid hydrolysates with presumptive higher absorption. Bacteria characterization, classification and isolation were performed from the collection at OSU in Jimenez' laboratory using 16S rDNA sequencing. Quantitative lipolysis and proteolytic activity were tested using α -naphthyl acetate, 4-nitrophenyl derivatives of C2-C14 and azocasien. Seven promising strains, one negative control, Staphylococcus warneri, and one positive control, Enterococcus faecalis were tested to screen their functional characteristics. Testing includes resistance to digestion including resisting low pH and bile salts, high values in auto-aggregation and hydrophobicity, and antimicrobial activity against indicator pathogenic strains: Escherichia coli ATCC 25922 and Listeria innocua ATCC 51742. Furthermore, antibiotics resistance was tested using eight antibiotics: chloramphenicol, vancomycin, tetracycline, erythromycin, ampicillin, kanamycin, clindamycin, and streptomycin. Virulence factors (agg, ace, asa1, fbp, cbp, mazm, eFaA, hdc, odc, tdc, ge (open full item for complete abstract)

Committee: Rafael Jimenez-Flores (Advisor); Sheila Jacobi (Committee Member); Ahmed Yousef (Committee Member); Hua Wang (Committee Member) Subjects: Food Science

Doctor of Philosophy, The Ohio State University, 2019, Food, Agricultural and Biological Engineering

Lactic acid is a platform chemical that can be utilized for a variety of applications in food, medical, packaging, and cosmetics industries. The global market for lactic acid is expected to grow substantially from $2.1 billion in 2016 to $9.8 billion in 2025. Lactic acid can be produced from both petroleum and biobased sources; however, the demand for lactic acid produced from biobased feedstock sources is expected to increase due to growing consumer awareness of the need for sustainability, biodegradability, recyclability and green packaging in different industries. Biobased lactic acid can be produced from starch-rich feedstocks, such as corn grain, and lignocellulosic feedstocks, such as corn stover and miscanthus. Lactic acid produced from biobased feedstocks can yield lactic acid isomers suitable for applications in the food and medical industries. Despite huge growth potential, the techno-economics and environmental impacts of different pathways for biobased lactic acid production are not well studied. Thus, the objective of this dissertation was to analyze the techno-economics and life cycle environmental impacts of producing lactic acid from biobased feedstocks, including corn grain, corn stover and miscanthus. These feedstocks were selected based on their current availability and future potential for biorefinery use in the U.S. The study evaluated different logistics and conversion pathways by developing comprehensive techno-economic and life cycle assessment models. The models incorporated data collected from the literature related to biomass production, harvest, post-harvest logistics and conversion to lactic acid. Three grain logistics scenarios were defined based on intermediate grain storage at 1) farm storage structure, 2) country elevator, and 3) both, before the grain delivery to the biorefinery. The 90% central range (CR) for the grain logistics cost, including costs for grain harvest, hauling, and storage, was $36-50 per metric ton (t). The grai (open full item for complete abstract)

Committee: Ajay Shah (Advisor); Erdal Ozkan (Committee Member); Harold M. Keener (Committee Member); Katrina Cornish (Committee Member) Subjects: Agricultural Engineering; Engineering

Master of Science, The Ohio State University, 2018, Comparative and Veterinary Medicine

Human noroviruses (HuNoVs) are responsible for more than 95% of the non-bacterial acute gastroenteritis epidemics in the world. The CDC estimates that every year 21 million individuals suffer from HuNoV-induced gastroenteritis in the U.S. Currently, there is no FDA-approved vaccine for HuNoVs. Development of an effective vaccine has been seriously hampered by the lack of an efficient cell culture system for HuNoVs and a suitable small animal model. The goal of this study is to develop lactic acid bacteria (LAB) as a vector to deliver HuNoV antigen. To do this, a LAB bacteria strain (Lactococcus lactis) carrying VP1 gene of a HuNoV GII.4 virus (LAB-VP1) was constructed. It was found that HuNoV VP1 protein was highly expressed by LAB vector. Subsequently, a novel microencapsulation technology was developed to enhance the stability of LABs in low and high pH environments. To test whether LAB-based HuNoV vaccine is immunogenic, 4-day-old gnotobiotic piglets were orally inoculated with various doses of LAB-VP1 either with or without microencapsulation. It was found that LABs were persistent in the small intestine of piglets and shed in pig feces for at least 25 days post inoculation. Live LABs or LAB DNA were found in mesenteric lymph nodes and spleen tissue in LAB-VP1 inoculated groups. HuNoV-specific IgG and IgA were detectable in serum and feces at day 13 post-inoculation, respectively, and further increased at late time points. After challenge with HuNoV GII.4 strain, a large amount of HuNoV antigens were observed in the duodenum, jejunum, and ileum sections of the intestine in the LAB control group. In contrast, significantly less or no HuNoV antigens were detected in the LAB-VP1 immunized groups. Collectively, these results demonstrate that LAB-based HuNoV vaccine induces protective immunity in gnotobiotic piglets.

Committee: Jianrong Li (Advisor); Prosper Boyaka (Committee Member); Melvin Pascall (Committee Member) Subjects: Microbiology; Virology

Doctor of Philosophy, The Ohio State University, 1986, Graduate School

Committee: Not Provided (Other) Subjects: Chemistry

Doctor of Philosophy, The Ohio State University, 1974, Graduate School

Committee: Not Provided (Other) Subjects: Health Sciences

Doctor of Philosophy, The Ohio State University, 1954, Graduate School

Committee: Not Provided (Other) Subjects: Engineering

Doctor of Philosophy, The Ohio State University, 1970, Graduate School

Committee: Not Provided (Other) Subjects: Agriculture

Doctor of Philosophy, The Ohio State University, 1960, Graduate School

Committee: Not Provided (Other) Subjects: Biology

Doctor of Philosophy in Clinical-Bioanalytical Chemistry, Cleveland State University, 2016, College of Sciences and Health Professions

The development of high fidelity Raman imaging systems is important for a number of application areas including material science, bio-imaging, bioscience and healthcare, pharmaceutical analysis, and semiconductor characterization. The use of Raman imaging as a characterization tool for detecting the amorphous and crystalline regions in the biopolymer poly-L-lactic acid (PLLA) is the precis of my thesis. In the first chapter, a brief insight about the basics of Raman spectroscopy, Raman chemical imaging, Raman mapping, and Raman imaging techniques has been provided. The second chapter contains details about the successful development of tailored sample of PLLA. Biodegradable polymers are used in areas of tissue engineering, agriculture, packaging, and in medical field for drug delivery, implant devices, and surgical sutures. Detailed information about the sample preparation and characterization of these cold-drawn PLLA polymer substrates has been provided. Wide-field Raman hyperspectral imaging using an acousto-optic tunable filter (AOTF) was demonstrated in the early 1990s. The AOTF contributed challenges such as image walk, distortion, and image blur. A wide-field AOTF Raman imaging system has been developed as part of my research and methods to overcome some of the challenges in performing AOTF wide-field Raman imaging are discussed in the third chapter. This imaging system has been used for studying the crystalline and amorphous regions on the cold-drawn sample of PLLA. Of all the different modalities that are available for performing Raman imaging, Raman point-mapping is the most extensively used method. The ease of obtaining the Raman hyperspectral cube dataset with a high spectral and spatial resolution is the main motive of performing this technique. As a part of my research, I have constructed a Raman point-mapping system and used it for obtaining Raman hyperspectral image data of various minerals, pharmaceuticals, and p (open full item for complete abstract)

Committee: John F. Turner II Ph.D. (Committee Chair); Xue-Long Sun Ph.D. (Committee Member); Aimin Zhou Ph.D. (Committee Member); Anthony J. Berdis Ph.D. (Committee Member); Petru S. Fodor Ph.D. (Committee Member) Subjects: Analytical Chemistry; Biomedical Engineering; Chemistry; Physics