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Title: THE EFFECTS OF ZINC NANOFERTILIZERS ON TOMATO PLANTS.
Creator: Pierre, Ketsira, Santra, Swadeshmukul, University of Central Florida
Abstract / Description: Farmers around the world aim to use soil with adequate nutrients to produce sufficient and quality crops to the world's ever-growing population. Unbalanced use of nutrients in the soil will lead to soil deficiency, which is usually seen in South and Southeast Asian countries. This soil deficiency is often due to loss of micronutrient(s) within the soil from farming practices. Micronutrient deficiency affects not only plant growth but human health. Plants grown in nutrient deficient soil...
Show moreFarmers around the world aim to use soil with adequate nutrients to produce sufficient and quality crops to the world's ever-growing population. Unbalanced use of nutrients in the soil will lead to soil deficiency, which is usually seen in South and Southeast Asian countries. This soil deficiency is often due to loss of micronutrient(s) within the soil from farming practices. Micronutrient deficiency affects not only plant growth but human health. Plants grown in nutrient deficient soil produce food with nutrient deficiencies, which affect people dependent on these foods for nutrients (Kathmandu, 2004). Nutrient deficient diseases and disorders like malnutrition are often seen in such cases. Current farming practices often involve leaching, mineralization, and bioconversion, which result in 50-70% loss of micronutrients. Smart practices from nanotechnology can lead conventional farming to more sustainable agriculture (Chhippa, 2016). This study aims to improve the dispersibility and uptake of zinc in plants different dual combination of ‘green' capping agents in zinc nanoparticles. The results of this study suggest tomato plants treated with urea coated with 3% Zn (w/w) using NAC-SAL ZnO showed a higher number of leaves and number of fruits set compared to controls.
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Date Issued: 2019
Identifier: CFH2000566, ucf:45665
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFH2000566

Title: ROOM TEMPERATURE SYNTHESIS AND SYSTEMATIC CHARACTERIZATION OF ULTRA-SMALL CERIA NANOPARTICLES.
Creator: Patel, Chetak, Santra, Swadeshmukul, University of Central Florida
Abstract / Description: Cerium oxide (ceria, CeO2) is a rare earth oxide that has attracted wide-spread research interest because of its unique properties such as high mechanical strength, oxygen ion conductivity, oxygen storage capacity and autocatalytic property. In recent years, researchers have discovered that ceria nanoparticles (NPs) are capable of protecting cells from free radical induced damage. Interestingly, it was found that nanometer size (~ 5 nm) ceria can scavenge free radicals quite efficiently, thus...
Show moreCerium oxide (ceria, CeO2) is a rare earth oxide that has attracted wide-spread research interest because of its unique properties such as high mechanical strength, oxygen ion conductivity, oxygen storage capacity and autocatalytic property. In recent years, researchers have discovered that ceria nanoparticles (NPs) are capable of protecting cells from free radical induced damage. Interestingly, it was found that nanometer size (~ 5 nm) ceria can scavenge free radicals quite efficiently, thus acting as an anti-oxidant. This phenomenon has been explained based on the autocatalytic property of ceria NPs. Several methods have been developed for the synthesis of ceria NPs that include flame combustion, hydroxide co-precipitation, hydrothermal/solvothermal, microemulsion, sonochemical and microwave-assisted heating methods and sol-gel method. Ceria NPs synthesized by these methods are often highly aggregated. Furthermore, large scale synthesis of monodispersed CeO2 NPs is quite challenging. Therefore it is desirable to synthesize ceria NPs in bulk quantity keeping its important properties intact, specifically free-radical scavenging property. The main goal of this study is therefore to synthesize ultra-small (< 5.0 nm), high quality monodispersed ceria NPs in large quantities. In this thesis work, I present a couple of room temperature techniques, dilute sodium hydroxide (NaOH) assisted and ethylenediamine (EN) assisted for the synthesis of nearly mono-dispersed, ultra-small (< 5 nm) and water-dispersible ceria NPs. Morphology and particle size of the ceria NPs were investigated through high resolution transmission electron microscopy (HRTEM). The HRTEM analysis confirmed the formation of 3.0 ± 0.5 nm size and 2.5 ± 0.2 nm size highly-crystalline ceria NPs when synthesized using dilute NaOH and EN as solvents, respectively. The nanostructures were characterized by X-ray diffraction (XRD) studies to determine the crystal structure and phase purity of the products. The samples were also thoroughly characterized by X-ray photoelectron spectroscopy (XPS) to determine the oxidation state of cerium ions. The presence of the +3 and +4 oxidation states in the samples was also confirmed from the XPS analysis. The co-existence of these two oxidation states is necessary for their applications as free radical scavenger. The autocatalytic behaviors of the ceria NPs were investigated through a hydrogen peroxide test and monitored by UV-visible transmission spectroscopy.
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Date Issued: 2009
Identifier: CFE0002883, ucf:48043
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0002883

Title: Nanoscale Functional Imaging by Tailoring Light-matter Interaction to Explore Organic and Biological Systems.
Creator: Otrooshi, Negar, Tetard, Laurene, Tatulian, Suren, Peale, Robert, Santra, Swadeshmukul, University of Central Florida
Abstract / Description: ABSTRACTProbing molecular systems with light has been critical to deepen our understanding of life sciences. However, conventional analytical methods fail to resolve small quantities of molecules or the heterogeneity in molecules assembled into complex systems. This bottleneck is mostly attributed to light diffraction limit. In recent years, the successful implementation of new approaches to achieve sub-wavelength chemical speciation with an Atomic Force Microscope (AFM) has paved the way to...
Show moreABSTRACTProbing molecular systems with light has been critical to deepen our understanding of life sciences. However, conventional analytical methods fail to resolve small quantities of molecules or the heterogeneity in molecules assembled into complex systems. This bottleneck is mostly attributed to light diffraction limit. In recent years, the successful implementation of new approaches to achieve sub-wavelength chemical speciation with an Atomic Force Microscope (AFM) has paved the way to a deeper understanding of the effect of local composition and structure on the functional properties of a larger scale system. The combination of infrared light, to excite the vibrational modes of a sample, and AFM detection to monitor the resulting local photothermal expansion has emerged as a powerful approach. In this work, we explore new applications of AFM-infrared (IR) to further the understanding of proteins and bacterial cells. We first consider the vibrational modes and secondary structure of proteins. We show that beyond the localized IR fingerprint of the system, light polarization could affect the response of the protein. To investigate this further, we combine the AFM-IR measurements with plasmonic substrates to tune the electromagnetic field. Using plasmonic structures, we map the electromagnetic field confinement using nanomechanical infrared spectroscopy. We detect and quantify, in the near field, the energy transferred to the lattice in the form of thermal expansion resulting from the heat generated. We compare the photothermal expansion patterns in the structures under linearly and circular polarized illumination. The results suggest the formation of hot spots, of great interest for biomolecules detection. Using a model system, poly-L-lysine, we show that the IR spectrum and the vibrational circular dichroism fingerprint of a chiral biological system can be probed at the nanoscale, far beyond the conventional limits of detection. The second part of the study focuses on utilizing the capabilities of AFM-IR to investigate bacterial cells and their responses to nanoparticle-based treatments. We highlight the potential of these new capabilities to further dive into the fundamental molecular mechanism of antibacterial activity and of development of drug resistance. We conclude this work by providing a perspective on the impact nanoscale functional imaging and spectroscopy can have on life sciences and beyond.
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Date Issued: 2019
Identifier: CFE0007897, ucf:52750
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007897

Title: Interplay of Molecular and Nanoscale Behaviors in Biological Soft Matter.
Creator: Ciaffone, Nicholas, Tetard, Laurene, Kang, Hyeran, Santra, Swadeshmukul, University of Central Florida
Abstract / Description: The complexity of biological soft matter at the sub-micrometer level is fundamentally correlated to the functionalities at the larger scale. Reflecting the level of heterogeneities in the properties of systems remains challenging when probing small scales, due to the mismatch between the area surveyed with the tools offering nanoscale resolution, such as atomic force microscopy (AFM), and the scale of natural variations inherent to biology. Hence, to understand the physiological and...
Show moreThe complexity of biological soft matter at the sub-micrometer level is fundamentally correlated to the functionalities at the larger scale. Reflecting the level of heterogeneities in the properties of systems remains challenging when probing small scales, due to the mismatch between the area surveyed with the tools offering nanoscale resolution, such as atomic force microscopy (AFM), and the scale of natural variations inherent to biology. Hence, to understand the physiological and mechanical alterations that occur within a single cell relative to a cell population, a multiscale approach is necessary. In this work we show that it is possible to observe molecular, chemical and physical alterations in both plant and human cells with a multiscale approach. Biophysical and biochemical traits of cell populations are studied with Fourier Transform infrared spectroscopy (FTIR) and in turn, guide higher resolution discovery with Raman spectroscopy and nanoscale infrared spectroscopy using AFM (NanoIR) to access finer details. We illustrate this with three examples of biological soft matter systems: 1) a preliminary study of cellular interactions with naturally occurring vehicles applicable to human health, 2) a qualitative examination of antibiotics and new pesticide treatments in food crop systems, and 3) a fundamental investigation of the deconstruction mechanisms of plant cells during pre-treatments in preparation for biofuel production.
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Date Issued: 2018
Identifier: CFE0007395, ucf:52058
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007395

Title: Development and Characterization of Solid-Contact Paper-Based and Micro Ion-Selective Electrodes for Environmental Analysis.
Creator: Armas, Stephanie, Chumbimuni Torres, Karin, Beazley, Melanie, Santra, Swadeshmukul, University of Central Florida
Abstract / Description: Ion-selective electrodes (ISEs) have extensively been used for food analysis, as medical diagnostic tools, and for some environmental applications. However, ISEs are hindered by the need of a bulky reference electrode and the pre-conditioning step of the sensor, which can often be lengthy. This work will discuss how the direct addition of target analyte into the cocktail sensing membrane can circumvent the pre-conditioning step. Furthermore, the work is presented in an optimized ready-to-use...
Show moreIon-selective electrodes (ISEs) have extensively been used for food analysis, as medical diagnostic tools, and for some environmental applications. However, ISEs are hindered by the need of a bulky reference electrode and the pre-conditioning step of the sensor, which can often be lengthy. This work will discuss how the direct addition of target analyte into the cocktail sensing membrane can circumvent the pre-conditioning step. Furthermore, the work is presented in an optimized ready-to-use single strip design, where the bulky glass reference electrode (RE) is no longer needed. The bulky RE was replaced by drop casting a simple two-component mixture consisting of the co-polymer methyl methacrylate-co-decyl methacrylate and the ionic liquid 1-Ethyl-3-methylimidazolium bis (trifluoromethane sulfonyl) amide. Furthermore, this work will also highlight the benefits of solid-contact ISEs, specifically focusing on two solid- contact platforms: 1) paper-based and 2) a micro-electrode platform. Paper-based based sensors were designed to be used as a possible diagnostic tool to be implemented in undeveloped countries to monitor low levels of potassium and iodide, as model ions. The micro((&)#181;) ISEs were applied for the in-situ analysis of zinc in citrus plants as a mean to monitor and assess disease progression or therapy.
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Date Issued: 2018
Identifier: CFE0007152, ucf:52316
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007152

Title: Nano-Biophysical Approaches for Assessing Nanoparticle Interactions with Biological Systems.
Creator: Untracht, Zachary, Kang, Ellen, Gesquiere, Andre, Santra, Swadeshmukul, University of Central Florida
Abstract / Description: Understanding interactions between nanoparticles and biological systems is fundamental for the development of emerging nano-biotechnology applications. In this thesis, I present an investigation of zinc oxide (ZnO) nanoparticles interactions with biomolecules in two separate studies. The first section of my thesis covers tracking and detection of ZnO nanoparticles using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). ZinkicideTM is a bactericidal ZnO nanoparticle which...
Show moreUnderstanding interactions between nanoparticles and biological systems is fundamental for the development of emerging nano-biotechnology applications. In this thesis, I present an investigation of zinc oxide (ZnO) nanoparticles interactions with biomolecules in two separate studies. The first section of my thesis covers tracking and detection of ZnO nanoparticles using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). ZinkicideTM is a bactericidal ZnO nanoparticle which has been developed for agriculture. The characterization of Zinkicide in biological media and in solution has been difficult due to its high dispersibility and ultra-small size. SDS-PAGE is considered a golden standard for protein qualitative interpretations. In this study, we have modified this typical protein assay and developed protocols for quantifying Zinkicide concentration, fluorescence intensity, and relative molecular weight changes in aqueous solutions. We found that SDS-PAGE is a novel and fundamental approach for assessing ZnO nanoparticles.The second part of my thesis is focused on investigating biological toxicity induced by nanoparticles. Recent studies have shown that nanoparticles have the capabilities to induce abnormalities on cellular networks including actin cytoskeleton. We have studied the effects of ZnO nanoparticles on filamentous actin assembly dynamics utilizing total internal reflection fluorescence (TIRF) microscopy imaging and biophysical analysis. The combination of these studies has provided pertinent information for the future development of nanoparticles designed for biological applications.
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Date Issued: 2019
Identifier: CFE0007738, ucf:52423
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007738

Title: Synthesis, Characterization And Antibacterial Activity Of Silver Embedded Silica Nanoparticle/Nanogel Formulation.
Creator: Menezes, Roseline, Santra, Swadeshmukul, Naser, Saleh, Self, William, University of Central Florida
Abstract / Description: The antibacterial property of silver (Ag) has been known since ancient time. It is reported in the literature that silver nanoparticles (AgNPs) exhibit improved antibacterial properties in comparison to silver ions of equivalent metallic Ag concentration. Such improvement in antibacterial activities is due to the high surface area to volume ratio of AgNPs (which facilitates interaction with the bacterial cells), increased release of silver ions and direct intra-cellular uptake of AgNPs...
Show moreThe antibacterial property of silver (Ag) has been known since ancient time. It is reported in the literature that silver nanoparticles (AgNPs) exhibit improved antibacterial properties in comparison to silver ions of equivalent metallic Ag concentration. Such improvement in antibacterial activities is due to the high surface area to volume ratio of AgNPs (which facilitates interaction with the bacterial cells), increased release of silver ions and direct intra-cellular uptake of AgNPs leading to localized release of Ag ions. To date, over 300 consumer products containing AgNPs are available in the market and the inventory is rapidly expanding. The antibacterial efficacy is related to the loading of AgNPs (which controls availability of active Ag ions). It is perhaps challenging to increase AgNPs loading in consumer products without compromising its aesthetic appearance. AgNPs exhibit yellow-brown color due to strong Surface Plasmon Resonance (SPR) absorption; and therefore, it is expected that an increase in loading would change the color of AgNP-containing materials. For applications, such as creating a fast-acting touch-safe surface, higher loading of AgNPs is desirable. It is also desirable to obtain a non-color forming surface. To meet the demands of desirable higher loading of AgNPs and non-color forming surface, the objective of this study is to minimize SPR by engineering Ag containing nanomaterials for potential fast-acting spray-based applications. Within this thesis several reports have been made including synthesis, characterization and antibacterial properties of Ag-loaded silica nanoparticle/nanogel (AgSiNP/NG) material containing nanoformulations. The effects of nanoformulation pH and metallic Ag content on the SPR absorption and antibacterial properties have been studied. The AgSiNP/NG materials were synthesized using silica sol-gel technique at room temperature in water. The color formation of the AgSiNP/NG material was found to be dependent on silver ion loading (15.4 wt% and 42.3 wt %) as well as on the pH (pH 4.0 and pH 7.0). A number of material characterization techniques such as HRTEM, SEM and AFM were used to characterize particle size, crystalline and surface morphology in dry state. Dynamic light scattering (DLS) technique was used to characterize particle size and size distribution in solution. UV-VIS spectroscopy technique was applied to characterize Ag ions and AgNPs in the AgSiNP/NG material. Antibacterial studies were conducted against gram negative E.coli and gram positive B.subtilis and S.aureus. A number of qualitative (well diffusion, BacLightTM live-dead(&)#174; viability) and quantitative (turbidity, resazurin viability) assays were used for antibacterial studies. It was observed that lower pH and low Ag loading minimized SPR absorption, resulting in no yellow-brown color formation. The HRTEM confirmed the formation of ~5-25 nm size highly crystalline AgNPs which were coated with dielectric silica layer (silica gel). AFM, SEM and DLS studies confirmed formation of AgSiNPs in the range between 100 nm (-) 200 nm. The AgSiNP/NG material was effective against both gram-negative and gram-positive bacteria. Based on this research it is suggested that by coating AgNPs with a dielectric material (such as silica); it is possible to suppress SPR absorption.
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Date Issued: 2011
Identifier: CFE0004483, ucf:49308
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0004483

Title: Novel copper loaded core-shell silica nanoparticles with improved copper bio-availability : Synthesis, characterization and study of antibacterial properties.
Creator: Maniprasad, Pavithra, Santra, Swadeshmukul, Self, William, Naser, Saleh, University of Central Florida
Abstract / Description: A novel core-shell silica based antimicrobial nanoparticle was synthesized. The St(&)#246;ber silica shell has been engineered to accommodate copper. Synthesis of the core-shell Cu-silica nanoparticle (C-S CuSiNP) involves preparation of base-hydrolyzed St(&)#246;ber silica (")seed(") particles first, followed by the acid-catalyzed seeded growth of the Cu-silica shell layer around the core. Scanning electron microscopy and transmission electron microscopy showed monodispersed, spherical...
Show moreA novel core-shell silica based antimicrobial nanoparticle was synthesized. The St(&)#246;ber silica shell has been engineered to accommodate copper. Synthesis of the core-shell Cu-silica nanoparticle (C-S CuSiNP) involves preparation of base-hydrolyzed St(&)#246;ber silica (")seed(") particles first, followed by the acid-catalyzed seeded growth of the Cu-silica shell layer around the core. Scanning electron microscopy and transmission electron microscopy showed monodispersed, spherical shaped nanoparticles with smooth surface morphology. Characterization of particle size distribution in solution by the Dynamic Light Scattering (DLS) technique was fairly consistent with the electron microscopy results. Loading of Cu to nanoparticles was confirmed by the SEM-Energy Dispersive X-Ray Spectroscopy (EDS) and Atomic Absorption Spectroscopy (AAS). Antibacterial efficacy of C-S CuSiNP was evaluated against E.coli and B.subtilis using Cu hydroxide ((")Insoluble(") Cu compound) and copper sulfate as positive control and silica (")seed(") particles (without Cu loading) as negative control. Minimum Inhibitory Concentration (MIC) of C-S CuSiNP was evaluated by measuring the fluorescent intensity of resorufin to determine the decrease in viable cells with increase in copper concentration in C-S CuSiNP. The MIC value of C-S CuSiNP against both E.coli and B.subtilis was estimated to be 4.9 ppm. Bac-light fluorescence microscopy based assay was used to count relative population of the live and dead bacteria cells. Antibacterial study clearly shows that C-S CuSiNP is more effective than insoluble Cu hydroxide particles and copper sulfate at equivalent metallic Cu concentration, suggesting more soluble Cu in C-S CuSiNP material due to its core-shell design.
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Date Issued: 2011
Identifier: CFE0004479, ucf:49300
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0004479

Title: Fate of Coated Zinc Oxide in Municipal Solid Waste Landfills.
Creator: Bolyard, Stephanie, Reinhart, Debra, Santra, Swadeshmukul, Randall, Andrew, University of Central Florida
Abstract / Description: Given the increase in nanomaterial (NM) use in consumer products and the large fraction of waste placed in landfills worldwide, the probability of these products reaching municipal solid waste (MSW) landfills at the end of their useful life is high. Since nanotechnology use is still in its early stages, there are currently no regulations pertaining to the disposal of NMs and their fate in MSW landfills is still unknown. Understanding the fate of NMs in MSW landfills is vital to ensure the...
Show moreGiven the increase in nanomaterial (NM) use in consumer products and the large fraction of waste placed in landfills worldwide, the probability of these products reaching municipal solid waste (MSW) landfills at the end of their useful life is high. Since nanotechnology use is still in its early stages, there are currently no regulations pertaining to the disposal of NMs and their fate in MSW landfills is still unknown. Understanding the fate of NMs in MSW landfills is vital to ensure the proper handling of these novel materials from cradle to grave; such research will provide information on how these NMs can be safely introduced into the environment. This research seeks to understand the fate of NMs within waste environments by examining the interactions between NMs and landfill leachate components. The primary focus of this thesis is the effect of Zinc Oxide (ZnO) on biological landfill processes, solids aggregation, and chemical speciation of Zn in landfill leachate following the addition of crystalline, nano-sized ZnO coated with triethoxycaprylylsilane. This research (1) observed the effects of coated ZnO on five-day biochemical oxygen demand (BOD5) and biochemical methane potential (BMP), (2) examined effects of solids aggregation on the fate of ZnO, (3) quantified the concentration of Zinc (Zn) by size fractions, and (4) modeled the chemical speciation of Zn in landfill leachate using Visual MINTEQ.No change in dissolved Zn was observed after coated ZnO was exposed to (")middle-aged(") leachate. Upon exposure to (")mature(") leachate there was an increase in dissolved Zn assumed to be a result of the dissociation of ZnO. Solids data supported the aggregation of particles in both middle aged and mature leachate. There was an increase in the Zn concentration in leachate fractions greater than 1500 nm presumably due to the dispersion of normally insoluble ZnO nanoparticles (NPs) following the interaction with humic acids (HA). ZnO did not inhibit anaerobic or aerobic processes in either middle aged or mature leachate, presumably due to the relatively low concentration of dissolved ionic Zn. Despite the observation of increased dissociation upon exposure to mature leachate, the presence of dissolved organic matter (DOM) may have hindered the ability for dissolved ionic Zn to become bioavailable. Fractionation, BOD5 and BMP tests, and chemical speciation modeling provided insight on the mobility of ZnO in landfills and the absence of inhibitory effects on landfill processes. Aggregation of ZnO NPs may prevent movement through traditional containment systems (i.e. geomembrane liners) due to the increased particle size. However, the increased dispersion suggests that ZnO NPs will be transported out of the landfill in the leachate, however biological treatment of leachate should be unaffected by the presence of ZnO. The bioavailability of Zn was not substantially affected by the presence of ZnO due to affinity of dissolved Zn for DOM. However, due to the heterogeneity of landfill leachate and the utilization of different NM coatings, it is challenging to predict the overall mobility of other NMs in a landfill.
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Date Issued: 2012
Identifier: CFE0004264, ucf:49509
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0004264

Title: Application of Landfill Treatment Approaches for the Stabilization of Municipal Solid Waste.
Creator: Bolyard, Stephanie, Reinhart, Debra, Santra, Swadeshmukul, Randall, Andrew, University of Central Florida
Abstract / Description: This research focused on the fundamental requirements of stabilizing a mature landfill using three treatment approaches as well as the implications of discharging leachate organic matter (LOM) to wastewater treatment plants (WWTPs). Three treatment approaches aimed at removing releasable carbon and nitrogen from mature landfills including flushing with clean water, leachate recirculation with ex-situ chemical oxidation, and leachate recirculation with ex-situ chemical oxidation and in-situ...
Show moreThis research focused on the fundamental requirements of stabilizing a mature landfill using three treatment approaches as well as the implications of discharging leachate organic matter (LOM) to wastewater treatment plants (WWTPs). Three treatment approaches aimed at removing releasable carbon and nitrogen from mature landfills including flushing with clean water, leachate recirculation with ex-situ chemical oxidation, and leachate recirculation with ex-situ chemical oxidation and in-situ aeration were evaluated. After extensive treatment of the waste in the flushing bioreactor (FB) scenarios, the overall biodegradable fraction was reduced relative to mature waste. Leachate quality improved for all FBs but through different mechanisms. Flushing was the most effective approach at removing biodegradable components and improving leachate quality. A mass balance on carbon and nitrogen revealed that a significant fraction still remained in the waste. Solid waste and leachate samples from the anaerobic bioreactors and FBs were characterized using Fourier Transform Infrared (FTIR) to provide a better understanding of changes in waste characteristics when waste transitions from mature to stabilized. Organic functional groups associated with aliphatic methylene were present in leachate and solid waste samples during the early stages of anaerobic degradation and disappeared once these wastes underwent treatment. Once the waste was stabilized, the FTIR spectra of leachate and solid waste were dominated by inorganic functional groups (carboxylic acid/carbonate group, carbonate, quartz, and clay minerals). Leachate is commonly co-treated with domestic wastewater due to the cost and complexity of on-site treatment. The organic constituents in leachate can be problematic for WWTPs as their recalcitrant components pass through conventional treatment processes, impacting effluent quality. Twelve leachates where characterized for total nitrogen (TN) and dissolved organic nitrogen (DON). The average concentration of TN and DON in leachate was 1,160 and 40.7 mg/L, respectively. Leachates were fractionated based on hydrophobic (recalcitrant; rDON) and hydrophilic (bioavailable; bDON) properties. The average concentrations of bDON and rDON were 16.5 and 18.4 mg/L, respectively. Multiple leachate and wastewater co-treatment simulations were carried out to assess the treatment of leachate nitrogen at historic nitrogen removal levels of four WWTPs and the effects on wastewater effluent quality for four WWTPs. The effluent quality exceeded typical TN limits of 3 to 10 mg/L at leachate volumetric contributions of 10%. The maximum calculated pass through concentrations of rDON and DON at 10% volumetric contribution for the twelve leachates was 4.77 and 9.71 mg/L, respectively. The effects of LOM on wastewater effluent quality was further evaluated in the field. Results showed that leachate detection for each field study could be determined using UV254 nm absorbance. DON and dissolved organic carbon (DOC) concentrations increased at significant levels in leachate-impacted wastewater samples. The DON decreased through the treatment train, suggesting that this parameter was effectively removed, while DOC persisted. DOC pass through coincided with an increase in color and UV254 nm absorption. In effluents, the UV254 nm transmittance was just below the minimum 65% disinfection requirement at dilutions greater than 1%. Leachate-impacted wastewater showed a higher concentration of humic-like peaks during fluorescence measurements than wastewater without leachate.
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Date Issued: 2016
Identifier: CFE0006076, ucf:50959
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006076

Title: Synthesis and Characterization of Core-Shell Zinc Silica Nanoparticles and Zinc Silica Nanogels for Agricultural Applications.
Creator: Berroth, Megan, Santra, Swadeshmukul, Moore, Sean, Jewett, Travis, University of Central Florida
Abstract / Description: Plant pathogens are a serious problem facing the agricultural industry today. Current methodologies use copper based biocides as the main form of defense. Unfortunately this can lead to damaging environmental effects and increased rates of antimicrobial resistance. In this study, antimicrobial activity of multiple alternative zinc-based nanoformulations were tested against three important plant pathogens: Xanthomonas alfalfae, Pseudomonas syringae, and Clavobacter michiganensis. Xanthomonas...
Show morePlant pathogens are a serious problem facing the agricultural industry today. Current methodologies use copper based biocides as the main form of defense. Unfortunately this can lead to damaging environmental effects and increased rates of antimicrobial resistance. In this study, antimicrobial activity of multiple alternative zinc-based nanoformulations were tested against three important plant pathogens: Xanthomonas alfalfae, Pseudomonas syringae, and Clavobacter michiganensis. Xanthomonas sub species cause Citrus canker, a devastating disease that affects millions of citrus trees worldwide while the latter two affect tomato crops. Materials synthesis was completed and the resulting nanoformulations were characterized by Atomic Absorption Spectroscopy, Scanning Electron Microscopy, High Resolution Transmission Electron Microscopy, and X-Ray Photoelectron Spectroscopy. The antimicrobial efficacy of the newly synthesized formulas and two commercially available products, Kocide 3000 (DuPont) and Nordox (Brandt), were determined by Minimum Inhibitory Concentration Assays followed by Bacterial Viability Assays. The subsequent data demonstrated a marketed difference in the way the antimicrobial agents acted upon the bacterial species. The core-shell zinc silica nanoparticles (C-SZnSiNP) proved to be ineffective, while the zinc silica nanogel (ZnSiNG) was as successful at killing the bacteria as the commercial products. This shows promise for a new alternative material with zinc at the forefront of the fight against plant pathogens.
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Date Issued: 2015
Identifier: CFE0006209, ucf:51099
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006209

Title: Synthesis and Characterization of Antimicrobial Non-Color Forming Silica-Silver Nanocomposite.
Creator: Bazata, Joshua, Santra, Swadeshmukul, Moore, Sean, Jewett, Travis, University of Central Florida
Abstract / Description: Silver has been utilized for its antimicrobial properties for thousands of years in a variety of fields, extending the shelf life of food and water, rendering eating utensils sanitary, and more recently in biomedical applications such as silver based antiseptic creams. While effective as an antimicrobial agent at very low concentrations ((&)#181;g/mL), silver imparts a strong color to objects it is incorporated into, due to its high plasmonic efficiency. The goal of this study was to...
Show moreSilver has been utilized for its antimicrobial properties for thousands of years in a variety of fields, extending the shelf life of food and water, rendering eating utensils sanitary, and more recently in biomedical applications such as silver based antiseptic creams. While effective as an antimicrobial agent at very low concentrations ((&)#181;g/mL), silver imparts a strong color to objects it is incorporated into, due to its high plasmonic efficiency. The goal of this study was to determine if incorporating silver nanoparticles into a silica matrix could reduce or eliminate the plasmonic signal, while retaining the antimicrobial effects of the silver nanoparticles.Citrate capped silver nanoparticles (AgNP) were synthesized using a borohydride reduction method as outlined by Zheng et. al., and incorporated into silica nanoparticles using a method adapted from Fleger et. al. To test the antimicrobial efficacy of these synthesized silica coated silver nanoparticles (SiAgNP), minimum inhibitory concentration testing at three time points, 1, 4, and 8 hours, was carried out against E. coli and S. aureus using broth microdilution and Alamar Blue as an indicator of microbial growth. Efficacy was judged against uncoated AgNP and aqueous silver nitrate (AgNO3) solutions at equivalent Ag concentrations. Silica nanoparticles (SiNP) were utilized as a negative control. Further antimicrobial characterization using a bacterial viability assay revealed a time dependent killing trend in the SiAgNP, suggesting a controlled release of Ag+ from within the silica matrix. Efficacy of the SiAgNP was determined to fall between the most effective antimicrobial form of silver tested, AgNO3, and least effective, AgNP. However, the SiAgNP material exhibited no visible plasmon peak when UV-Visible spectrophotometric readings were taken, as well as remaining colorless when coated onto a ceramic substrate. Zeta potential revealed a high degree of colloidal stability of the SiAgNP. TEM imaging studies were carried out, verifying the presence of Ag within and on the silica nanoparticles, as well as the crystalline structure of the uncoated AgNP. It was determined that coating AgNP synthesized through borohydride reduction with silica through a St(&)#246;ber synthesis mechanism yields a material with enhanced antimicrobial effects compared to AgNP, but with no detectable plasmon signal, effectively producing a non-color forming silver based antimicrobial.
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Date Issued: 2015
Identifier: CFE0006208, ucf:51097
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006208

Title: Screening of Quantum Dots for Toxicity on the Growth and Viability of Escherichia coli.
Creator: Tharkur, Jeremy, Santra, Swadeshmukul, Self, William, Moore, Sean, University of Central Florida
Abstract / Description: Heavy metal (HM) containing quantum dots (Qdots) are increasingly used in commercial products due to their unique electronic, optoelectronic, optical and magnetic properties. Once disposed to the landfill, environmental weathering is likely to compromise HM Qdot integrity, leading to release of heavy metal ions. To minimize any negative environmental impact of HM Qdots, there is an increasing demand for developing HM free or environmentally-friendly surface modified HM Qdot alternatives. In...
Show moreHeavy metal (HM) containing quantum dots (Qdots) are increasingly used in commercial products due to their unique electronic, optoelectronic, optical and magnetic properties. Once disposed to the landfill, environmental weathering is likely to compromise HM Qdot integrity, leading to release of heavy metal ions. To minimize any negative environmental impact of HM Qdots, there is an increasing demand for developing HM free or environmentally-friendly surface modified HM Qdot alternatives. In this study, synthesis of HM free ZnS:Mn/ZnS and surface modified HM CdS:Mn/ZnS Qdots (using N-acetylcysteine, NAC, and Dihydrolipoic acid, DHLA) and their potential toxicity assessment using E. coli as a model system is reported. NAC and DHLA are known antioxidants and therefore expected to reduce HM induced toxicity and improve colloidal stability of Qdots. All Qdots were synthesized at room temperature using a reverse micelle microemulsion method. Qdots were fully characterized using UV-visible absorption spectroscopy, fluorescence emission spectroscopy, zeta potential, Nuclear Magnetic Resonance spectroscopy (NMR) and High Resolution Transmission Electron Microscopy (HRTEM). Qdot environmental weathering was simulated by treating Qdots with concentrated acid (6N HCl). Qdot toxicity was evaluated on E. coli growth and viability using growth curves, turbidity and bactericidal assays (CFU). Results show that Zn based Qdots exhibit reduced toxicity on E.coli growth and viability when compared to Cd based Qdots. In addition, surface modification with NAC and DHLA minimized toxicity of Cd based Qdots. In summary, Zn based Qdots appear to be more environmental-friendly than Cd based Qdots.
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Date Issued: 2013
Identifier: CFE0005426, ucf:50416
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005426

Title: Mixed Valence Copper(Cu)/Silica Nanocomposite: Synthesis, Characterization and Systematic Antimicrobial Studies.
Creator: Young, Mikaeel, Santra, Swadeshmukul, Self, William, Moore, Sean, University of Central Florida
Abstract / Description: Copper (Cu) compounds are widely used as effective agricultural bactericides. Continuous use of these materials has led to Cu accumulation in soil over time. The United States Environmental Protection Agency (US EPA) is concerned about potential Cu contamination in the environment. Improving biocidal efficacy of Cu is an attractive alternative, allowing reduction of Cu amount per application. In this research, we focused on making water-soluble mixed-valence Copper/Silica composite nanogel ...
Show moreCopper (Cu) compounds are widely used as effective agricultural bactericides. Continuous use of these materials has led to Cu accumulation in soil over time. The United States Environmental Protection Agency (US EPA) is concerned about potential Cu contamination in the environment. Improving biocidal efficacy of Cu is an attractive alternative, allowing reduction of Cu amount per application. In this research, we focused on making water-soluble mixed-valence Copper/Silica composite nanogel (CuSiNG) material. The objective is to improve the efficacy of Cu by manipulating Cu valence states. It has been shown in the literature that Cu (0) and Cu (I) states are more potent that Cu (II) states in terms of their antimicrobial efficacy. It is hypothesized that mixed valence Cu will exhibit improved efficacy over Cu (II). A water-soluble mixed valence Cu/silica nanogel (MV-CuSiNG) composite has been synthesized and characterized. Structure, morphology, crystallinity and composition of the MV-CuSiNG material was characterized using High-Resolution Transmission Electron Microscopy (HRTEM), HRTEM Selected Area Electron Diffraction (SAED) and X-ray Photoelectron Spectroscopy (XPS). Amount of Cu loading in MV-CuSiNG composite material was estimated by Atomic Absorption Spectroscopy (AAS). To confirm presence of Cu (I) in the MV-CuSiNG material, Neocuproine (Nc, a Cu (I) specific chelator) assay was used. Antimicrobial efficacy of MV-CuSiNG and CuSiNG was evaluated against X.alfalfae, B.subtilis and E.coli using Kocide(&)#174; 3000 ((")Insoluble Cu (II)(") compound), Copper sulfate ((")Soluble Cu (II)(") compound) and Cuprous chloride (Copper (I) compound) as positive controls and silica (")seed(") particles (without Cu loading) as negative control. Antimicrobial studies included observing bacterial growth inhibition and determining the Minimum Inhibitory Concentration (MIC). Improved antimicrobial efficacy was observed in MV-CuSiNG when compared to CuSiNG and other controls. For the assessment of plant safety of MV-CuSiNG and CuSiNG materials, phytotoxicity studies were conducted using Vinca sp and Hamlin orange under environmental conditions. It was observed that MV-CuSiNG material was safe to plants at commercially used (standard) spray application rate.
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Date Issued: 2013
Identifier: CFE0005282, ucf:50550
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005282

Title: Zinc Sulfide:manganese doped Quantum rods for detection of metal ions and a business model for future sales.
Creator: Teblum, Andrew, Santra, Swadeshmukul, Gesquiere, Andre, Soskin, Mark, University of Central Florida
Abstract / Description: Hexavalent chromium is an extremely carcinogenic chemical that has been widely produced in the United States. This has led to major waste contamination and pollution throughout the country. According to the Environmental Working Group Hexavalent chromium has been found in 89% of city tap water. Most people believe they are safe using regular home filter systems however that is not true. A more expensive ion exchange water treatment unit is required. Therefore to protect yourselves from this...
Show moreHexavalent chromium is an extremely carcinogenic chemical that has been widely produced in the United States. This has led to major waste contamination and pollution throughout the country. According to the Environmental Working Group Hexavalent chromium has been found in 89% of city tap water. Most people believe they are safe using regular home filter systems however that is not true. A more expensive ion exchange water treatment unit is required. Therefore to protect yourselves from this carcinogenic metal a reliable test is required. In this study we have developed a Zinc Sulfide Manganese doped Quantum Rod technology to detect for presence of chromate and other harmful transitional metals in drinking water. Quantum Rods were synthesized using a hydrothermal reaction method. They were fully characterized using UV-visible absorption spectroscopy, fluorescence emission spectroscopy, X-ray Photoelectric Spectroscopy (XPS) and High Resolution Transmission Electron Microscopy (HRTEM). Quantum Rod metal detection studies were done with 28 different ions in a 96-well fluorescent plate reader. Results show that highest sensitivity to 8 ions including the toxic ions of chromate and mercury allowing us to create a sensor to detect these items.
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Date Issued: 2014
Identifier: CFE0005268, ucf:50569
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005268

Title: Metastable-State Photoacids: Synthesis, Properties, and Applications.
Creator: Patel, Parth, Chumbimuni Torres, Karin, Hernandez, Florencio, Santra, Swadeshmukul, Beazley, Melanie, Lee, Woo Hyoung, University of Central Florida
Abstract / Description: Reversible photochromic compounds have the ability to reversibly change its color when it absorbs photons of a particular wavelength. This process of color change is a consequence of structural changes within the compound, such as cis-trans photo-isomerization. Some examples of photochromic compounds are spiropyrans, spirooxazines, diarylethenes and azobenzenes. These compounds have been extensively studied for decades, and are used in various applications such as biomedicine, chemical...
Show moreReversible photochromic compounds have the ability to reversibly change its color when it absorbs photons of a particular wavelength. This process of color change is a consequence of structural changes within the compound, such as cis-trans photo-isomerization. Some examples of photochromic compounds are spiropyrans, spirooxazines, diarylethenes and azobenzenes. These compounds have been extensively studied for decades, and are used in various applications such as biomedicine, chemical sensors and harvesting solar energy. However, majority of photochromic compounds are initially activated by ultraviolet (UV) light. The use of UV light is harmful for biological applications and photo-degrade the compound over repeated use. To overcome these limitations, a new class of reversible photochromic compound was introduced, called metastable-state photoacid (mPAH). In brief, mPAH is a photochromic compound which can photo-dissociate its protons under visible light and can thermally re-capture the released protons efficiently in the dark. Based on this unique property, in this research, we (1) synthesized different mPAH, and (2) studied and characterized their physicochemical (acidity, kinetics, and optical) properties. Additionally, we (3) applied different visible light activated mPAHs towards light controllable polymeric-based ion-selective optodes for detection of calcium ions and sodium ions, and modulate fluorescence with pH. The research presented herein opens new avenues towards the synthesis of mPAH derivatives and could be applied to any proton-transfer process related applications which requires wireless controllability with high sensitivity.
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Date Issued: 2019
Identifier: CFE0007849, ucf:52769
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007849

Title: Coated Quantum Dots: Engineering of Surface Chemistry for Biomedical and Agricultural Applications.
Creator: Maxwell, Tyler, Santra, Swadeshmukul, Gesquiere, Andre, Harper, James, Zou, Shengli, Leon, Lorraine, University of Central Florida
Abstract / Description: Quantum dots (QDs) are crystalline nanoparticles made from semiconductor material with sizes ranging from 1 to 10 nm in diameter. QDs are attractive fluorophores for bioimaging and sensing due to their size-dependent optical properties, broad absorption bands, high extinction coefficients and superior photostability. The combination of imaging and drug delivery in a single particle can provide valuable information and improve the efficacy of existing treatments. This dissertation highlights...
Show moreQuantum dots (QDs) are crystalline nanoparticles made from semiconductor material with sizes ranging from 1 to 10 nm in diameter. QDs are attractive fluorophores for bioimaging and sensing due to their size-dependent optical properties, broad absorption bands, high extinction coefficients and superior photostability. The combination of imaging and drug delivery in a single particle can provide valuable information and improve the efficacy of existing treatments. This dissertation highlights the use of QDs for biomedical and agricultural applications. Chapter 1 of this dissertation presents a background of QDs and outlines the synthesis methods of producing and functionalizing QDs. A discussion of the advantages and limitations of each method for producing water-soluble QDs and the rationale for the proposed research is also presented. Chapter 2 describes an activatable QD design for tracking of drug delivery for cancer treatment. QDs synthesized by microemulsion (ME) were cross-linked in a one-step procedure. Enhanced binding affinity of the probe to cell lines overexpressing folate receptors was shown through fluorescence microscopy. However, this system is not practical for the large-scale synthesis due to its complexity and can not be translated for clinical development. Chapter 3 presents a sol-gel synthesis method for producing water-soluble QDs utilizing the thiol-based small molecule capping agent as the stabilizer as an alternative to ME technique. This method was designed to be a simple (one-step), cost-effective, and scalable for making both manganese doped CdS and ZnS QDs. QDs were synthesized through sol-gel method with a library of organic thiol coatings and characterized by size, surface charge, stability, and optical properties. These particles were compared to QDs produced from ME synthesis and were found to have similar properties. Chapter 4 reports the sol-gel QDs as slow-release antibiotic delivery system for application as agricultural bactericide. Utilizing electrostatic interactions, the QDs were shown to be capable of improving the leaf adhesion and slowing the rate of release of streptomycin. Chapter 5 presents a summary of the major findings of this research and discusses the future research directions.
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Date Issued: 2019
Identifier: CFE0007681, ucf:52476
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007681

Title: Cerium oxide nanoparticles act as a unique catalyst and scavenge nitric oxide and peroxynitrite and decrease RNS in vitro and in vivo.
Creator: Dowding, Janet, Self, William, Bossy-Wetzel, Ella, Zervos, Antonis, Seal, Sudipta, Santra, Swadeshmukul, University of Central Florida
Abstract / Description: Cerium oxide nanoparticles (CeO2 NPs)(nanoceria) have been shown to possess a substantial oxygen storage capacity via the interchangeable surface reduction and oxidation of cerium atoms, cycling between the Ce4+ and Ce3+ redox states. Reduction of Ce4+ to Ce3+ causes oxygen vacancies or defects on the surface of the crystalline lattice structure of the particles, generating a cage for redox reactions to occur. The study of the chemical and biological properties of CeO2 NPs has expanded...
Show moreCerium oxide nanoparticles (CeO2 NPs)(nanoceria) have been shown to possess a substantial oxygen storage capacity via the interchangeable surface reduction and oxidation of cerium atoms, cycling between the Ce4+ and Ce3+ redox states. Reduction of Ce4+ to Ce3+ causes oxygen vacancies or defects on the surface of the crystalline lattice structure of the particles, generating a cage for redox reactions to occur. The study of the chemical and biological properties of CeO2 NPs has expanded recently, and the methods used to synthesize these materials are also quite diverse. This has led to a plethora of studies describing various preparations of CeO2 NPs for potential use in both industry and for biomedical research. Our own work has centered on studies that measure the ability of water-based CeO2 NPs materials to reduce reactive oxygen and nitrogen species in biological systems, and correlating changes in surface chemistry and charge to the catalytic nature of the particles. The application in experimental and biomedical research of CeO2 NPs began with the discovery that water-based cerium oxide nanoparticles could act as superoxide dismutase mimetics followed by their ability to reduce hydrogen dioxide similar to catalase. While their ROS scavenging ability was well established, their ability to interact with specific RNS species, specifically nitric oxide (NO) or peroxynitrite (ONOO-) was not known. The studies described in this dissertation focus on the study of RNS and cerium oxide nanoparticles.Our in vitro work revealed that CeO2 NPs that have higher levels of reduced cerium sites (3+) at the surface (which are effective SOD mimetics) are also capable of accelerating the decay of peroxynitrite in vitro. In contrast, CeO2 NPs that have fewer reduced cerium sites at the particle surface (which also exhibit better catalase mimetic activity) have NO scavenging capabilities as well as some reactivity with peroxynitrite. Our studies and many others have shown cerium oxide nanoparticles can reduce ROS and RNS in cell culture or animal models. The accumulation of ROS and RNS is a common feature of many diseases including Alzheimer's disease (AD). Testing our CeO2 NPS in cortical neurons, we used addition of A? peptide as an AD model system. CeO2 NPs delayed A?-induced mitochondrial fragmentation and neuronal cell death. When mitochondrial ROS levels are increased, mitochondrial fission is activated by DRP1 S616 phosphorylation. Specifically, our studies showed the reduction of phosphorylated DRP1 S616 in the presence of CeO2 NPs. Results from our studies have begun to unravel the molecule mechanism behind the catalytic nature of how CeO2 NPs reduce ROS/RNS in biological systems and represents an important step forward to test the potential neuroprotective effects of CeO2 NPs in model systems of AD.A plethora of studies describing various preparations of CeO2 NPs for potential use in both industry and for biomedical research have been described in the past five years. It has become apparent that the outcomes of CeO2 NPs exposure can vary as much as the synthesis methods and cell types tested. In an effort to understand the disparity in reports describing the toxicity or protective effects of exposure to CeO2 NPs, we compared CeO2 NPs synthesized by three different methods; H2O2 (CNP1), NH4OH (CNP2) or hexamethylenetetramine (HMT-CNP1). Exposure to HMT-CNP1 led to reduced metabolic activity (MTT) at a 10-fold lower concentration than CNP1 or CNP2 and surprisingly, exposure to HMT-CNP1 led to substantial decreases in the ATP levels. Mechanistic studies revealed that HMT-CNP1 and CNP2 exhibited robust ATPase (phosphatase) activity, whereas CNP1 lacked ATPase activity. HMT-CNP1 were taken up into HUVECs far more efficiently than the other preparations of CeO2 NPs. Taken together, these results suggest the combination of increased uptake and ATPase activity of HMT-CNP1 may underlie the mechanism of the toxicity of this preparation of CeO2 NPs, and may suggest ATPase activity should be considered when synthesizing CeO2 NPs for use in biomedical applications. Overall the studies have uncovered two new catalytic activities for water-based CeO2 NPs (NO scavenging and accelerated decay of peroxynitrite), demonstrated their ability to reduce RNS in an AD cell culture model as well as identifying a catalytic activity (phosphatase) that may underlie the observed toxicity of CeO2 NPs reported in other studies.
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Date Issued: 2012
Identifier: CFE0004782, ucf:49783
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0004782

Title: Preparation, Characterization, and Delivery of Antibodies Binding to a Model Oncogenic RNA, Human Initiator tRNA.
Creator: Archer, Jennifer, Santra, Swadeshmukul, Ye, Jingdong, Ye, Jingdong, Self, William, Khaled, Annette, University of Central Florida
Abstract / Description: Non-coding RNAs (ncRNAs) account for a higher percent of the genome than coding mRNAs, and are implicated in human disease such as cancer, neurological, cardiac and many others. While the majority of ncRNAs involved in disease were originally attributed to a class of RNAs called micro RNAs (miRNAs) with a small size of only about 19 -24 base pairs, emerging research has now demonstrated a class of long non-coding RNAs (lncRNAs) that have a size of over 200 base pairs to be responsible for...
Show moreNon-coding RNAs (ncRNAs) account for a higher percent of the genome than coding mRNAs, and are implicated in human disease such as cancer, neurological, cardiac and many others. While the majority of ncRNAs involved in disease were originally attributed to a class of RNAs called micro RNAs (miRNAs) with a small size of only about 19 -24 base pairs, emerging research has now demonstrated a class of long non-coding RNAs (lncRNAs) that have a size of over 200 base pairs to be responsible for gene regulation and other functional roles and have also found to contribute to pathogenesis in humans. The increased size and structural complexity require novel tools to study their interactions beyond RNA interference. Synthetic antibodies are classic tools and therapeutics utilized to study and treat proteins involved in human disease. Likewise we hypothesize that structured RNAs can also take advantage of synthetic antibodies to probe their functions and be utilized as therapeutics.Currently, antibodies have been raised against microbial riboswitches and other structured RNAs of single-celled organisms, and only one human structured RNA to the best of our knowledge. However, no one has yet to create a synthetic antibody capable of behaving as a therapeutic against a structured RNA. We therefore sought to raise an antibody Fab against a structured RNA, human initiator tRNA, a model oncogenic non-coding RNA and demonstrate its efficacy in vitro. We then characterized the antibody and explored delivery options in cancer cells including the use of nanoparticle delivery systems. With the emerging transcriptome revealing new ncRNAs implicated in human disease, our research has begun to address a new therapeutic strategy, laying down the foundation for the future of structured RNA-targeted therapies.
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Date Issued: 2014
Identifier: CFE0005756, ucf:50072
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005756

Title: Synthesis and Study of Chemo-Hydrothermally Derived Water-Soluble Chitosan and Chiosan-Metal Oxide Composites.
Creator: Basumallick, Srijita, Santra, Swadeshmukul, Kolpashchikov, Dmitry, Zou, Shengli, Ye, Jingdong, Seal, Sudipta, University of Central Florida
Abstract / Description: Chitosan (CS) is a man-made sugar based biopolymer derived from chitin, the second most abundant natural polymer after cellulose. Chitin is sourced from crustacean species such as shrimps and crabs. The chemical structure of chitin contains N-Acetyl D-glucosamine monomer units which forms CS upon deacetylation. In CS, ?-(1-4) linked D-glucosamine units are randomly distributed. Approximately 75% - 80% sugar units contains primary amine groups in commercially available low molecular weight CS....
Show moreChitosan (CS) is a man-made sugar based biopolymer derived from chitin, the second most abundant natural polymer after cellulose. Chitin is sourced from crustacean species such as shrimps and crabs. The chemical structure of chitin contains N-Acetyl D-glucosamine monomer units which forms CS upon deacetylation. In CS, ?-(1-4) linked D-glucosamine units are randomly distributed. Approximately 75% - 80% sugar units contains primary amine groups in commercially available low molecular weight CS. Biodegradability, low toxicity, mucoadhesive and transfecting properties of CS polymer are attractive for applications as oral and nasal drug delivery systems. Chitosan polymer is water insoluble at neutral pH. To solubilize CS, dilute mineral acid (such as hydrochloric acid and nitric acid) or organic acid (such as acetic acid) is often used. CS contains both hydroxyl and primary amine groups in its structure. In acidic solution, the amine functional groups become protonated (positively charged). Positively charged CS remains stable only in low pH condition due to electrostatic repulsion of charged polymer segments. Therefore, by using a suitable anionic (negatively charged) cross-linker, stable CS particles (such as nanoparticles and microspheres) can be prepared. This is popularly known as ionic gelation method. Extensive studies have been done on the synthesis of drug loaded CS particles where particle integrity is maintained by ionic gelation using tripolyphosphate (TPP, an anionic cross-linker). Drug encapsulated CS-TPP composite particles are shown to maintain biodegradability and biocompatibility. The CS-TPP composite particles exhibits very limited dispersibility at neutral pH conditions specifically in neutral buffered conditions. A number of biomedical applications (including systemic drug formulations) however demands buffer-stable CS composite particles for achieving optimal therapeutic outcome.To overcome the above dispersibility issues, CS polymer and CS particles units have been chemically modified using water soluble motifs (such as water soluble polymer or ligands). This approach is very cumbersome and usually involves multiple purification steps. Chemical modification of natural CS chain introduces risks of compromising biodegradability and biocompatibility. Therefore, there is a strong need for developing a straightforward method of making water soluble CS and CS particles.Chapter 1 of this dissertation presents an overview of the CS polymer, various applications of CS polymers, methods of making CS polymers and CS particles, current limitations of synthesis methods for preparing stable chitosan particles at neutral pH conditions and finally delineates the scope of the proposed research work.Chapter 2 describes development of chemo-hydrothermal synthesis method for producing water soluble CS polymer and water dispersible CS composite particles. In this method, a chemical (depolymerizing agent) is used to treat CS polymer in a hydrothermal (high temperature and high pressure) condition. Two types of depolymerizing agents have been used, an inorganic acid (e.g. hydrochloric acid, HCl) and a bicarboxylic organic acid (e.g. tartaric acid, TA). In both cases, 100% depolymerized CS polymer was obtained. Chemical characteristics of the depolymerized CS were comparable to acid solubilized CS. CS polymer exhibits weak fluorescence. Interestingly, hydrothermally depolymerized CS shows strong fluorescence properties irrespective of the nature of depolymerizing agent used. TA not only depolymerized CS but also formed CS-TA composite particulate structures in solution via self-assembly. The CS-TA composite particles are stable in a wide pH range from 5 to 11. Detailed spectroscopic and microscopic studies have been done to understand the basic mechanism of particle formation and increase in fluorescence properties (i.e. structure-property relationship). Usefulness of CS-TA in solubilizing water-insoluble cargos (such as fluorescein isothiocyanate, FITC) has been demonstrated.Chapter 3 is focused on hydrothermal synthesis of mixed-valence copper (Cu) oxide loaded CS-TA composite particles and their characterization. Crystalline Cu oxide nanoparticles were coated with the CS-TA layer. Water dispersibility of Cu oxide greatly improved upon coating with CS-TA material. To demonstrate catalytic activity of Cu-oxide loaded CS-TA film in sequestering carbon dioxide (CO2), an electrochemical setup was used. Electrochemical reduction of CO2 was successfully demonstrated. It was observed that CS-TA environment not only maintained catalytic properties of Cu oxide but also allowed solution processing of Cu-oxide film onto the electrode surface.Chapter 4 discusses a convenient method of making monodispersed water dispersible Cu loaded chitosan nanoparticles (Cu-CS) using HCl depolymerized CS polymer. The purpose of this study was to investigate if there was any improvement in antibacterial properties of Cu-CS nanoparticles prepared using hydrothermally treated CS polymer. Interestingly, it was observed that the antibacterial efficacy of Cu was not compromised in Cu-CS nanoparticles. Moreover, the materials exhibited improvement in antibacterial efficacy against both Gram-negative and Gram-positive bacteria species. A plausible mechanism has been proposed to explain antibacterial results.Chapter 5 summarizes major findings of this dissertation research and presents future research directions.
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Date Issued: 2014
Identifier: CFE0005461, ucf:50395
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005461

nanoparticles (3)	+ -
Antimicrobial (2)	+ -
Atomic Force Microscopy (2)	+ -
Raman Spectroscopy (2)	+ -
Silica (2)	+ -

nanoparticle (2)	+ -
AFM (1)	+ -
AFM-IR (1)	+ -
Actin (1)	+ -
Alzheimer's disease (1)	+ -
Antibacterial studies (1)	+ -
Antibody (1)	+ -
Biocide (1)	+ -
Cerium oxide nanoparticles (1)	+ -
Chemo Hydrothermally Treated (1)	+ -
Chitin (1)	+ -
Chitosan (1)	+ -
Chromate (1)	+ -
Clavobacter michiganensis (1)	+ -
Confocal Raman Microscopy (1)	+ -
Copper (1)	+ -
Copper-Chitosan (1)	+ -
DHLA (1)	+ -
Dissolved Organic Nitrogen (1)	+ -
E.coli (1)	+ -
Electron Microscopy (1)	+ -
FTIR (1)	+ -
Fab (1)	+ -
Fluorescence (1)	+ -
Gel Electrophoresis (1)	+ -

ETD Collection (22)	+ -
Honors Collection (1)	+ -

Santra, Swadeshmukul (23)	+ -
University of Central Florida (23)	+ -
Self, William (6)	+ -
Chumbimuni Torres, Karin (4)	+ -
Gesquiere, Andre (4)	+ -

Moore, Sean (4)	+ -
Ye, Jingdong (4)	+ -
Tetard, Laurene (3)	+ -
Beazley, Melanie (2)	+ -
Bolyard, Stephanie (2)	+ -
Hernandez, Florencio (2)	+ -
Jewett, Travis (2)	+ -
Kang, Hyeran (2)	+ -
Kolpashchikov, Dmitry (2)	+ -
Naser, Saleh (2)	+ -
Randall, Andrew (2)	+ -
Reinhart, Debra (2)	+ -
Seal, Sudipta (2)	+ -
Zhai, Lei (2)	+ -
Zou, Shengli (2)	+ -
Archer, Jennifer (1)	+ -
Armas, Stephanie (1)	+ -
Basumallick, Srijita (1)	+ -
Bazata, Joshua (1)	+ -
Berroth, Megan (1)	+ -
Bonner, Maxwell (1)	+ -
Bossy-Wetzel, Ella (1)	+ -
Campiglia, Andres (1)	+ -
Ciaffone, Nicholas (1)	+ -
Dowding, Janet (1)	+ -

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