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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Imidazole-Containing Polymerized Ionic Liquids for Emerging Applications: From Gene Delivery to Thermoplastic Elastomers

Allen, Michael H. Jr. 07 January 2013 (has links)
Novel imidazole-containing polyelectrolytes based on poly(1-vinylimidazole) (poly(1VIM)) were functionalized with various hydroxyalkyl-substituents to investigate the influence of charge density and hydrogen bonding on nonviral DNA delivery.  Copolymers with higher charge densities exhibited increased cytotoxicity, whereas increased hydroxyl concentrations remained nontoxic.  DNA binding affinity increased with increased charge densities and increased hydroxyl content.  Dynamic light scattering determined the copolymers which delivered DNA most effectively maintained an intermediate binding affinity between copolymer and DNA.  Copolymers containing higher charge densities or hydroxyl concentrations bound DNA too tightly, preventing its release inside the cell.  Copolymers with lower charge densities failed to protect the DNA from enzymatic degradation.  Tuning hydrogen bonding concentration allowed for a less toxic and more effective alternative to conventional, highly charged polymers for the development of nonviral DNA delivery vehicles.  The synthesis of amine-containing imidazolium copolymers functionalized with low concentrations of folic acid enabled the investigation of additional polymer modifications on nonviral gene delivery.   Functionalization of 1VIM with various hydroxyalkyl and alkyl groups and subsequent conventional free radical polymerization afforded a series of imidazolium-containing polyelectrolytes.  Hydroxyl-containing homopolymers exhibited higher thermal stabilities and lower T<sub>g</sub>'s compared to the respective alkyl-analog.  X-ray scattering demonstrated the polarity of the hydroxyl group facilitated solvation of the electrostatic interactions disrupting the nanophase-separated morphology observed in the alkylated systems.  Impedance spectroscopy determined hydroxyl-containing imidazolium homopolymers displayed higher ionic conductivities compared to the alkyl-containing analogs which was attributed to increased solvation of electrostatic interactions in the hydroxyl analogs. Beyond functionalizing 1VIM monomers and homopolymers to tailor various properties, the synthesis of novel architectures in a controlled fashion remains difficult due to the radically unstable N-vinyl propagating radical.  The regioisomer 4-vinylimidazole (4VIM) contains two resonance structures affording increased radical stability of the propagating radical.  Nitroxide-mediated polymerization (NMP) and atom transfer radical polymerization (ATRP) failed to control 4VIM homopolymerizations; however, reversible addition-fragmentation chain transfer (RAFT) demonstrated unprecedented control.  Linear pseudo-first order kinetics were observed and successful chain extension with additional 4VIM suggested preservation of the trithiocarbonate functionality. Effectively controlling the polymerization of 4VIM enabled the design of amphoteric block copolymers for emerging applications.  The design of ABA triblock copolymers with 4VIM as a high T<sub>g</sub> supporting outer block and di(ethylene glycol) methyl ether methacrylate (DEGMEMA) as a low T<sub>g</sub>, inner block, required the development of a new difunctional RAFT chain transfer agent (CTA).  The difunctional CTA successfully mediated the synthesis of the ABA triblock copolymer, poly(4VIM-b-DEGMEMA-b-4VIM), which exhibited microphase separated morphologies.  The amphoteric nature of the imidazole ring required substantially lower concentrations of outer block incorporation compared to traditional triblock copolymers to achieve similar mechanical properties and microphase separated morphologies. / Ph. D.
42

Design of Functional Polyesters for Electronic and Biological Applications

Nelson, Ashley M. 12 August 2015 (has links)
Melt polymerization and novel monomers enabled the synthesis of polyesters for electronic and biological applications. Inspiration from nature and a passion for environmental preservation instigated an emphasis on the incorporation of renewable resources into polymeric materials. Critical analysis of current research surrounding bisphenol-A replacements and ioncontaining segmented polyurethanes aided in identifying benchmark polymers, including limitations, challenges, and future needs. Structure-property-morphology relationships were investigated to evaluate the polymers for success in the proposed applications as well as to improve understanding of polyester compositions to further design and develop sophisticated polymers for emerging applications. Aiming to utilize the reported [2 + 2] cycloaddition of the known mesogen 4,4’-dimethyltrans-stilbene dicarboxylate (SDE) to overcome ultraviolet (UV) induced degradation issues in electronic encasings, the synthesis of copolyesters containing SDE ensued. 1,6-Hexanediol (HD) and 1,4-butanediol comonomers in varying weight ratios readily copolymerized with SDE under melt transesterification conditions to afford a systematic series of copolyesters. Differential scanning calorimetry revealed all copolyesters exhibited liquid crystalline transitions and melting temperatures ranged from 196 °C – 317 °C. Additionally, melt rheology displayed shear thinning to facilitate melt processing. Compression molded films exhibited high storage moduli, a glassy plateau until the onset of flow, and tensile testing revealed a Young’s iii modulus of ~900 MPa for poly(SDE-HD). These properties enable a wide range of working temperatures and environments for electronic applications. Adding complexity to linear liquid crystalline copolyesters, copolymerization with oligomeric hydroxyl-functionalized polyethers afforded segmented liquid crystalline copolyesters. 4,4’-Biphenyl dicarboxylate (BDE), commercially available diols containing 4, 5, 6, 8, or 10 methylene units, and introducing poly(tetramethylene oxide) or a Pluronic® triblock oligoethers in varying weight % were used to synthesize multiple series of segmented copolyesters. Comparing melting transitions as a function of methylene spacer length elucidated the expected even-odd effect and melting temperatures ranged from 150 °C to 300 °C. Furthermore, incorporating the flexible soft segment did not prevent formation of a liquid crystalline morphology. Complementary findings between differential scanning calorimetry and small-angle X-ray scattering confirmed a microphase-separated morphology. Thermomechanical analysis revealed tunable plateau moduli and temperature windows based on both soft segment content and methylene spacer length, and tensile testing showed the strain at break doubled from 75 weight % to 50 weight % hard segment content. The same compositions Young’s moduli decreased from 107 ± 12 MPa at 75 weight % hard segment to 19 ± 1 MPa with 50 weight % hard segment, demonstrating the mechanical trade-off and range of properties possible with small compositional changes. These segmented copolyesters could find use in high-performance applications including electronic and aerospace industries. A two-step synthesis transformed caffeine into a novel caffeine-containing methacrylate (CMA). Conventional free radical copolymerization with a comonomer known to provide a low glass transition temperature (Tg), 2-ethylhexyl methacrylate (EHMA), allowed the investigation of the effect of small amounts of pendant caffeine on polymer properties. Thermal and iv thermomechanical testing indicated CMA incorporation dramatically increased the storage modulus, however, a microphase-separated morphology was not attained. Association of the pendant caffeine groups through non-covalent π-π stacking could present opportunities for novel thermoplastics and it is proposed that placing the pendant group further from the backbone, and potentially increasing the concentration, could aid in promoting microphase-separation. Alkenes are reactive sites for placing functional groups, particularly those required for polyester synthesis. Methyl 9-decenoate (9-DAME), a plant-based fatty acid, provided a platform for novel biodegradable, renewable, polyesters. A formic acid hydration reaction generated an isomeric mixture of AB hydroxyester or AB hydroxyacid monomers for melt polymerization. Thermal analysis elucidated the plant-based polyesters exhibited a single transition, a Tg of about -60 °C. Aliphatic polyesters commonly crystallize, thus the isomeric mixture of secondary alcohols seemed to introduce enough irregularity to prevent crystallization. These polyesters offer an amorphous, biodegradable, sustainable replacement for applications currently using semi-crystalline poly(ε-caprolactone), which is not obtained from renewable monomers and also exhibits a -60 °C Tg. Additional applications requiring low-Tg polymers such as pressure sensitive adhesives or thermoplastic elastomers could also benefit from these novel polyesters. 9-DAME also was transformed into an ABB’ monomer after an epoxidation and subsequent hydrolysis. Successful gelation under melt transesterification conditions provided evidence that the multifunctional monomer could perform as a renewable, biodegradable, branching and/or crosslinking agent. Novel copolyesters comprised of a bromomethyl imidazolium diol and adipic acid demonstrated potential as non-viral gene delivery vectors. Melt polycondensation produced water dispersible polyesters which bound deoxyribonucleic acid at low N/P ratios. The v polyplexes showed stability in water over 24 h and no cytotoxic effect on human cervical cancer cells (HeLa). A luciferase transfection assay revealed the copolyesters successfully underwent endocytosis and released the nucleic acid better than controls. The copolyesters with pendant imidazolium functionality also provided tunable Tgs, -41 °C to 40 °C, and the ability to electrospin into fibers upon blending with poly(ethylene oxide). These additional properties furthered potential applications to include pressure sensitive adhesives and biocompatible antibacterial bandages. / Ph. D.
43

THE DEVELOPMENT OF MICROFLUIDIC DEVICES FOR THE PRODUCTION OF SAFE AND EFFECTIVE NON-VIRAL GENE DELIVERY VECTORS

Absher, Jason Matthew 01 January 2018 (has links)
Including inherited genetic diseases, like lipoprotein lipase deficiency, and acquired diseases, such as cancer and HIV, gene therapy has the potential to treat or cure afflicted people by driving an affected cell to produce a therapeutic protein. Using primarily viral vectors, gene therapies are involved in a number of ongoing clinical trials and have already been approved by multiple international regulatory drug administrations for several diseases. However, viral vectors suffer from serious disadvantages including poor transduction of many cell types, immunogenicity, direct tissue toxicity and lack of targetability. Non-viral polymeric gene delivery vectors (polyplexes) provide an alternative solution but are limited by poor transfection efficiency and cytotoxicity. Microfluidic (MF) nano-precipitation is an emerging field in which researchers seek to tune the physicochemical properties of nanoparticles by controlling the flow regime during synthesis. Using this approach, several groups have demonstrated the successful production of enhanced polymeric gene delivery vectors. It has been shown that polyplexes created in the diffusive flow environment have a higher transfection efficiency and lower cytotoxicity. Other groups have demonstrated that charge-stabilizing polyplexes by sequentially adding polymers of alternating charges improves transfection efficiency and serum stability, also addressing major challenges to the clinical implementation of non-viral gene delivery vectors. To advance non-viral gene delivery towards clinical relevance, we have developed a microfluidic platform (MS) that produces conventional polyplexes with increased transfection efficiency and decreased toxicity and then extended this platform for the production of ternary polyplexes. This work involves first designing microfluidic devices using computational fluid dynamics (CFD), fabricating the devices, and validating the devices using fluorescence flow characterization and absorbance measurements of the resulting products. With an integrated separation mechanism, excess polyethylenimine (PEI) is removed from the outer regions of the stream leaving purified polyplexes that can go on to be used directly in transfections or be charge stabilized by addition of polyanions such as polyglutamic acid (PGA) for the creation of ternary polyplexes. Following the design portion of the research, the device was used to produce binary particle characterization was carried out and particle sizes, polydispersity and zeta potential of both conventional and MS polyplexes was compared. MS-produced polyplexes exhibited up to a 75% reduction in particle size compared to BM-produced polyplexes, while exhibiting little difference in zeta potential and polydispersity. A variety of standard biological assays were carried out to test the effects of the vectors on a variety of cell lines – and in this case the MS polyplexes proved to be both less toxic and have higher transfection efficiency in most cell lines. HeLa cells demonstrated the highest increase in transgene expression with a 150-fold increase when comparing to conventional bulk mixed polyplexes at the optimum formulation. A similar set of experiments were carried out with ternary polyplexes produced by the separation device. In this case it was shown that there were statistically significant increases in transfection efficiency for the MS-produced ternary polyplexes compared to BM-produced poyplexes, with a 23-fold increase in transfection activity at the optimum PEI/DNA ratio in MDAMB-231 cells. These MS-produced ternary polyplexes exhibited higher cell viability in many instances, a result that may be explained but the reduction in both free polymer and ghost particles.
44

Lipid Modified Polymers for Transfection of Human CRL Fibroblasts, and for siRNA Mediated MDR Reversal in Melanoma Cancer Therapy

Abbasi Dezfouli, Meysam Unknown Date
No description available.
45

Lipid Modified Polymers for Transfection of Human CRL Fibroblasts, and for siRNA Mediated MDR Reversal in Melanoma Cancer Therapy

Abbasi Dezfouli, Meysam 11 1900 (has links)
Gene delivery for therapeutic purposes is quickly emerging as the best potential treatment option for inherited genetic diseases and cancer. Viral gene carriers have been the choice for this purpose due to their high efficiency, but harmful immunogenic and oncogenic host reactions have limited their in vivo use. Cationic polymers provide a safe alternative to viral carriers as they can be engineered to reduce immunogenic and toxic responses and serve therapeutic purposes in the body. Due to their strong positive charge, they are able to compact the negatively charged nucleotides to small nano-sized particles appropriate for cellular uptake. Additionally, they efficiently encapsulate the highly sensitive nucleotides, and protect them against degradation by the nucleases present at the physiological milieu. In this thesis work, I have used a novel approach for gene delivery by combining the critical properties of a cationic polymer (i.e., nucleotide condensing ability) with that of a fatty acid (i.e., lipid membrane compatibility). The resulting lipid modified polymer increased delivery of our gene of interest into target cells and resulted in increased siRNA delivery for cancer gene therapy. / Biomedical Sciences
46

Evaluation of Immunogene Therapy Using a Plasmid Encoding IL-15 Delivered by Electroporation in a 3D Tumor Model and a Mouse Melanoma Model

Marrero, Bernadette 02 November 2010 (has links)
Melanoma is an aggressive disease with few effective treatment options. Non-toxic, anti-tumor therapies and prophylactic approaches are currently being investigated to identify treatment options that will control and remove late-stage melanoma. The overall goal of this project was to establish an effective delivery method for a plasmid encoding human interleukin (phIL-15) into mouse melanoma cells (B16.F10) using the gene transfer technique electroporation (EP)1. The EP delivery phIL-15 was optimized using an in vitro 3D tumor model. The purpose was to translate these IL-15 delivery conditions into an in vivo mouse melanoma model to study IL-15 signal transduction and stimulate immune cells to destroy tumor antigens as well as promote an anti-tumor immune memory response. The in vitro 3D tumor model and the mouse model demonstrated similar expression patterns when delivering phIL-15 with different EP conditions. Intra-tumoral delivery using 500V/cm 20ms enhanced gene delivery and increased IL-15 protein expression compared to 1300V/cm 100μs. There was also a visible increase in transfection efficacy between tumor cells compared to skin cells when delivering pmIL-12 and phIL-15 plasmid constructs in vivo. The plasmid+EP groups 1300V/cm and 500V/cm stimulated increased expression of cytokines IL-1β, IL-6, INFγ, MIP-1β and TNFα. These EP groups also promoted tumor regression by up-regulating CD8+ T cells and CD4+ T cells which targeted melanoma. Regression and survival studies demonstrated that 73.3% of mice cleared B16.F10 cells when treated with phIL-xi15+1300V/cm and pVax+500V/cm. In addition, 53% of the mice responded to the phIL-15+500V/cm treatment group. Furthermore, 75% of the mice from group phIL-15+500V/cm survived secondary inoculation and tumor challenge. In conclusion, plasmid with encoding gene insert phIL-15 delivered by EP has the potential to act as an anti-tumor therapy because it promotes melanoma regression and enhances mouse survival through innate and adaptive cell-mediated immune responses.
47

REGENERATION OF DAMAGED GROWTH PLATE USING IGF-I PLASMID-RELEASING POROUS PLGA SCAFFOLDS

Ravi, Nirmal 01 January 2009 (has links)
Growth plate injuries account for 15-30% of long bone fractures in children. About 10% of these result in significant growth disturbances due to formation of a boney bar. If not treated correctly, this can lead to life-lasting consequences of limb length inequalities and angular deformities. Current treatments for growth plate injuries include removal of boney bar and insertion of fat, silicone, bone cement, etc.. This treatment y is inadequate, leaving almost half of these patients with continued deformities. This dissertation reports characterization of a DNA–containing porous poly(lactic-co-glycolic acid) (PLGA) scaffold system, chondrogenesis using insulin-like growth factor I (IGF-I) plasmid-releasing scaffolds in vitro, and in vivo testing of IGF-I plasmid-releasing scaffolds to regenerate growth plate . Controlled release of naked and DNA complexed with polyethylenimine (PEI) was achieved from porous PLGA scaffolds. PEI affected release of complexes from PLGA scaffolds, as PEI:DNA complexes were released at a lower rate compared to naked DNA encapsulated in low molecular weight (LMW) and high molecular weight PLGA scaffolds, as well as hydrophilic and hydrophobic PLGA scaffolds. Hydrophilicity and molecular weight of PLGA affected the release profiles of both naked DNA and PEI:DNA complexes from the scaffolds, as evidenced by later peak DNA and PEI:DNA release with increasing hydrophilicity and molecular weight. LMW hydrophilic PLGA scaffolds supported growth and chondrogenic differentiation of mesenchymal multipotent D1 cells, chondrocytes, and bone marrow cells (BMCs) in vitro. Culturing BMCs on IGF-I plasmid-encapsulated scaffolds resulted in elevated expression of IGF-I compared to blank scaffolds. Removal of boney bar and implantation of IGF-I plasmid-releasing LMW PLGA scaffolds in a rabbit model of growth plate injury resulted in some improvement of leg angular deformity compared to no scaffold implantation. Histological analysis of the newly developed cartilage showed growth plate-like columnar arrangement of chondrocytes in a defect that received IGF-I plasmid encapsulated scaffold, although the level of organization of newly formed cartilage was inferior to that of native growth plate. This appears to be the first report of the regeneration of growth plate-like structure without the use of stem cells in an animal model of physeal injury.
48

Propriétés structurales et associations en solution des dendrimères polyamidoamine (Pamam) / Structural properties of pamam dendrimers and their interactions in solution

Zerrad, Louiza 13 January 2010 (has links)
Nouveaux polymères avec une structure arborescente unique, les dendrimères suscitent un grand intérêt auprès des chercheurs de tous les domaines scientifiques confondus et spécialement auprès des biologistes. Théoriquement synthétisés de façon à ce qu’ils soient parfaitement mono disperses en taille et en masse et de forme sphérique, les dendrimères PAMAM ont des propriétés structurales qui pourraient donner de bons résultats lors de leur utilisation comme vecteurs de médicaments ou d’acides nucléiques.De récentes études biologiques ont montré que les dendrimères PAMAM pouvaient transfecter un grand nombre de cellules de différente nature. Les propriétés structurales et physicochimiques du dendrimère joueraient un rôle essentiel dans l’efficacité de cette transfection et pouvoir prédire ces propriétés permettraient de mieux contrôler le comportement de ces«vecteurs-médicaments» dans l’organisme / In the context of securing clinical gene transfer, new strategies are developed with the creationof synthetic gene vectors based on cationic polymers to replace commonly used viral vectors ingene therapy. PAMAM dendrimers are highly branched macromolecules with controlled nearmonodisperse three-dimensional architecture emanating from a central core. Polymer growthstarts from a central core molecule and growth occurs in an outward direction by a series ofpolymerisation reactions. Hence, precise control over size can be achieved by the extent ofpolymerisation, starting from a few nanometers. Cavities in the core structure and folding of thebranches create cages and channels. The surface groups of dendrimers are amenable tomodification and can be tailored for specific applications. Therapeutic and diagnostic agents areusually attached to surface groups on dendrimers by chemical modification.Recent biological studies have shown that PAMAM dendrimers could transfect a large numberof cells of different nature. The structural properties and physico-chemical properties ofdendrimer play a key role in the efficiency of transfection and to predict these properties wouldbetter control the behavior of these "drug delivery systems in the body.
49

ENGINEERING OF POLYAMIDOAMINE (PAMAM) DENDRIMERS FOR GENE AND DRUG DELIVERY

Yuan, Quan 30 April 2012 (has links)
Dendrimers are a class of polymers with a highly branched, three-dimensional architecture composed of an initiator core, several interior layers of repeating units and multiple surface groups. They have been recognized as the most versatile compositionally and structurally controlled nanoscale building blocks throughout the fields of engineering, materials science, chemistry, and biology, and they have been widely investigated for drug and gene delivery. Polyamidoamine (PAMAM) dendrimers have inherent properties for gene delivery because of their high buffering capacity, polycationic surface and numerous surface groups for biofunctionlization. This dissertation is organized into four independent sections. The first section investigates a series of polyamidoamine-polyethylene glycol-poly (D,L-lactide) (G3.0- PEG1500-PDLLA, G3.0-PEG6000-PDLLA, and G3.0-PEG12000-PDLLA) for gene delivery. Western Blot, fluorescence microscopy and flow cytometry were used as analysis methods. According to gene transfection studies, G3.0-PEG1500-PDLLA has been shown to be capable of inducing higher gene expression than the parent dendrimer compared to unmodified dendrimer, G3.0-PEG6000-PDLLA and G3.0-PEG12000- PDLLA. The second section aims to evaluate an epidermal growth factor (EGF)-containing PAMAM G4.0 dendrimer vector labeled with quantum dots for targeted imaging and nucleic acid delivery. Targeting efficiency, cell viability, proliferation, and intracellular signal transduction were evaluated. We found that EGF-conjugated dendrimers did not stimulate growth of epidermal growth factor receptor (EGFR)-expressing cells at the selected concentration. Consistent with this, minimal stimulation of post-receptor signaling pathways was observed. These nanoparticles can localize within cells that express the EGFR in a receptor-dependent manner, whereas uptake into cells lacking the receptor was low. Vimentin short hairpin RNA (shVIM) and yellow fluorescent protein (YFP) small interfering RNA (siRNA) were used to test the delivery and transfection efficiency of the constructed targeted vector. Significant knockdown of expression was observed, indicating that this vector is useful for introduction of nucleic acids or drugs into cells by a receptor-targeted mechanism. The third section introduces PEGylated polyamidoamine (PAMAM) dendrimer G4.0 conjugates with a novel bis-aryl hydrazone (BAH) linkage for gene delivery. It was found that the incorporation of BAH linkages into the vector significantly enhanced the buffering capacity of the vector with a high degree of PEGylation. According to gene transfection studies, this new vector has been shown to be capable of both transfecting more cells and inducing higher gene expression than the parent dendrimer. This work demonstrates that the use of the BAH linkage in coupling of PEG to the dendrimer helps maintain or increase the buffering capacity of the functionalized dendrimer and results in enhanced transfection. In the fourth section, we explored PAMAM dendrimer G4.5 as the underlying carrier to construct central nervous system (CNS) therapeutic nanoparticles and tested the buccal mucosa as an alternative absorption site for administration of the dendritic nanoparticles. Opioid peptide DPDPE was chosen as a model CNS drug. It was coupled to PAMAM dendrimer G4.5 with PEG or with PEG and transferrin receptor monoclonal antibody OX26. The therapeutic dendritic nanoparticles labeled with 5-(aminoacetamido) fluorescein (AAF) or fluorescein isothiocyanate (FITC) were studied for transbuccal transport using a vertical Franz diffusion cell system mounted with porcine buccal mucosa. Coadministration of bile salt sodium glycodeoxycholate (NaGDC) or application of mucoadhesive gelatin/PEG semi-interpenetrating network (sIPN) enhanced the permeability of dendritic nanoparticles by multiple folds. These results indicate that transbuccal delivery is a possible route for administration of CNS therapeutic nanoparticles. In summary, enhanced nucleic acids delivery by biofunctionalized PAMAM dendrimers was demonstrated. Transbuccal delivery of CNS therapeutic dendritic nanoparticles was demonstrated. These vectors will be useful in gene and drug delivery and could be extended to covalently conjugate other functional moieties for gene and drug delivery.
50

Delivery and Scavenging of Nucleic Acids by Polycationic Polymers

Jackman, Jennifer Gamboa January 2016 (has links)
<p>Electrostatic interaction is a strong force that attracts positively and negatively charged molecules to each other. Such an interaction is formed between positively charged polycationic polymers and negatively charged nucleic acids. In this dissertation, the electrostatic attraction between polycationic polymers and nucleic acids is exploited for applications in oral gene delivery and nucleic acid scavenging. An enhanced nanoparticle for oral gene delivery of a human Factor IX (hFIX) plasmid is developed using the polycationic polysaccharide, chitosan (Ch), in combination with protamine sulfate (PS) to treat hemophilia B. For nucleic acid scavenging purposes, the development of an effective nucleic acid scavenging nanofiber platform is described for dampening hyper-inflammation and reducing the formation of biofilms.</p><p>Non-viral gene therapy may be an attractive alternative to chronic protein replacement therapy. Orally administered non-viral gene vectors have been investigated for more than one decade with little progress made beyond the initial studies. Oral administration has many benefits over intravenous injection including patient compliance and overall cost; however, effective oral gene delivery systems remain elusive. To date, only chitosan carriers have demonstrated successful oral gene delivery due to chitosan’s stability via the oral route. In this study, we increase the transfection efficiency of the chitosan gene carrier by adding protamine sulfate to the nanoparticle formulation. The addition of protamine sulfate to the chitosan nanoparticles results in up to 42x higher in vitro transfection efficiency than chitosan nanoparticles without protamine sulfate. Therapeutic levels of hFIX protein are detected after oral delivery of Ch/PS/phFIX nanoparticles in 5/12 mice in vivo, ranging from 3 -132 ng/mL, as compared to levels below 4 ng/mL in 1/12 mice given Ch/phFIX nanoparticles. These results indicate the protamine sulfate enhances the transfection efficiency of chitosan and should be considered as an effective ternary component for applications in oral gene delivery.</p><p>Dying cells release nucleic acids (NA) and NA-complexes that activate the inflammatory pathways of immune cells. Sustained activation of these pathways contributes to chronic inflammation related to autoimmune diseases including systemic lupus erythematosus, rheumatoid arthritis, and inflammatory bowel disease. Studies have shown that certain soluble, cationic polymers can scavenge extracellular nucleic acids and inhibit RNA-and DNA-mediated activation of Toll-like receptors (TLRs) and inflammation. In this study, the cationic polymers are incorporated onto insoluble nanofibers, enabling local scavenging of negatively charged pro-inflammatory species such as damage-associated molecular pattern (DAMP) molecules in the extracellular space, reducing cytotoxicity related to unwanted internalization of soluble cationic polymers. In vitro data show that electrospun nanofibers grafted with cationic polymers, termed nucleic acid scavenging nanofibers (NASFs), can scavenge nucleic acid-based agonists of TLR 3 and TLR 9 directly from serum and prevent the production of NF-ĸB, an immune system activating transcription factor while also demonstrating low cytotoxicity. NASFs formed from poly (styrene-alt-maleic anhydride) conjugated with 1.8 kDa branched polyethylenimine (bPEI) resulted in randomly aligned fibers with diameters of 486±9 nm. NASFs effectively eliminate the immune stimulating response of NA based agonists CpG (TLR 9) and poly (I:C) (TLR 3) while not affecting the activation caused by the non-nucleic acid TLR agonist pam3CSK4. Results in a more biologically relevant context of doxorubicin-induced cell death in RAW cells demonstrates that NASFs block ~25-40% of NF-ĸβ response in Ramos-Blue cells treated with RAW extracellular debris, ie DAMPs, following doxorubicin treatment. Together, these data demonstrate that the formation of cationic NASFs by a simple, replicable, modular technique is effective and that such NASFs are capable of modulating localized inflammatory responses. </p><p>An understandable way to clinically apply the NASF is as a wound bandage. Chronic wounds are a serious clinical problem that is attributed to an extended period of inflammation as well as the presence of biofilms. An NASF bandage can potentially have two benefits in the treatment of chronic wounds by reducing the inflammation and preventing biofilm formation. NASF can prevent biofilm formation by reducing the NA present in the wound bed, therefore removing large components of what the bacteria use to develop their biofilm matrix, the extracellular polymeric substance, without which the biofilm cannot develop. The NASF described above is used to show the effect of the nucleic acid scavenging technology on in vitro and in vivo biofilm formation of P. aeruginosa, S. aureus, and S. epidermidis biofilms. The in vitro studies demonstrated that the NASFs were able to significantly reduce the biofilm formation in all three bacterial strains. In vivo studies of the NASF on mouse wounds infected with biofilm show that the NASF retain their functionality and are able to scavenge DNA, RNA, and protein from the wound bed. The NASF remove DNA that are maintaining the inflammatory state of the open wound and contributing to the extracellular polymeric substance (EPS), such as mtDNA, and also removing proteins that are required for bacteria/biofilm formation and maintenance such as chaperonin, ribosomal proteins, succinyl CoA-ligase, and polymerases. However, the NASF are not successful at decreasing the wound healing time because their repeated application and removal disrupts the wound bed and removes proteins required for wound healing such as fibronectin, vibronectin, keratin, and plasminogen. Further optimization of NASF treatment duration and potential combination treatments should be tested to reduce the unwanted side effects of increased wound healing time.</p> / Dissertation

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