Advanced analytical techniques were utilized to investigate the intermolecular forces in several nanostructured materials. Techniques including, but not limited to, isothermal titration calorimetry (ITC), variable temperature Fourier transform infrared (FTIR) spectroscopy, and ultraviolet-visible (UV-Vis) thermal curves were used to study the fundamental interactions present in various nanomaterials, and to further probe the influence of these interactions on the overall behavior of the material. The areas of focus included self-assembly of surfactant micelles, polycation complexation of DNA, and temperature-dependent hydrogen bonding in polymeric systems. ITC was successfully used to determine the low critical micelle concentration (CMC) for a novel gemini surfactant with limited water solubility. CMCs were measured at decreasing methanol molar fractions (xMeOH) in water and the resulting linear relationship between CMC and methanol concentration was used to mathematically extrapolate to a predicted CMC at xMeOH = 0. Using this technique, the CMC value for the novel gemini surfactant was predicted to be 0.037 ± 0.004 mM. This extrapolation technique was also validated with surfactant standards. ITC was also used to investigate the binding thermodynamics of polyplex formation with polycations and DNA. The imidazolium-containing and trehalose-based polycations were both found to have endothermic, entropically driven binding with DNA, while the adenine-containing polycation exhibited exothermic DNA binding. In addition, ITC was also used to confirm the stoichiometric binding ratio of linear polyethylenimine and DNA polyplexes as determined by a novel NMR method. Dynamic light scattering (DLS) and zeta potential measurements were also performed to determine the size and surface charge of polyplexes. Circular dichroism (CD) and FTIR spectroscopies provided information regarding the structural changes that may occur in the DNA upon complexation with polymers. UV-Vis thermal curves indicated that polyplexes exhibit a greater thermal stability than DNA by itself. Variable temperature FTIR spectroscopy was used to quantitatively compare the hydrogen bonding behavior of multi-walled carbon nanotube (MWCNT)-polyurethane composites. Spectra were collected from 35 to 185 deg C for samples containing various weight percent loadings of MWCNTs with different hydrogen bonding surface functionalities. Peak fitting analysis was performed in the carbonyl-stretching region for each sample, and the hydrogen-bonding index (Rindex) was reported. Rindex values were used to quantitatively compare all of the composite samples in regards to temperature effects, weight percent loadings of MWCNTs, and the different functionalizations. In general, higher weight percent loadings of the MWCNTs resulted in greater Rindex values and increased hydrogen bond dissociation temperatures. In addition, at 5 and 10 wt% loadings the initial Rindex values displayed a trend that tracked well with the increasing hydrogen bonding capacity of the various surface functionalities. / Ph. D.

Non-covalent intermolecular interactions play a large role in determining the properties of a given system, from segmented copolymers to interactions of functionalized polymers with non-viral nucleic acids delivery vehicles. The ability to control the intermolecular interactions of a given system allow for tailoring of that system to yield a desired outcome, whether it is a copolymers mechanical properties or the colloidal stability of a pDNA-delivery vector complex. Each chemical system relies on one or more types of intermolecular interaction such as hydrogen bonding, cooperative À-À stacking, electrostatic interactions, van der waals forces, metal-ligand coordination, or hydrophobic/solvophobic effects. The following research describes the tailoring of specific intermolecular interactions aimed at altering the physical properties of segmented copolymers and non-viral gene delivery vectors. Amide containing segmented copolymers relies heavily on hydrogen bonding intermolecular interactions for physical crosslinking to impart the necessary microphase separated morphology responsible for a copolymers physical properties. Amide containing hard segments are composed of various chemical structures from crystalline aramids to amorphous alkyl amides with each structure possessing unique intermolecular interactions. Variations to either of the copolymer segments alters the copolymers physical properties allowing for tuning of a copolymers properties for a particular application. The synthetic strategies, structure-property relationships, and physical properties of amide containing segmented copolymers are thoroughly reported in the literature. Each class of segmented copolymer that contain amide hydrogen bonding groups exhibits a wide range of tunable properties desirable for many applications. The segmented copolymers discussed here include poly(ether-block-amide)s, poly(ether ester amide)s, poly(ester amide)s, poly(oxamide)s, PDMS polyamides, and polyamides containing urethane, urea, or imide groups. The structure-property relationships (SPR) of poly(oxamide) segmented copolymers is not well understood with only one report currently found in literature. The effects of oxamide spacing in the hard segment and molecular weight of the soft segments in PDMS poly(oxamide) segmented copolymers demonstrated the changes in physical properties associated with minor structural variations. The optically clear PDMS poly(oxamide) copolymers possessed good mechanical properties after bulk polymerization of ethyl oxalate terminated PDMS oligomers with alkyl diamines or varied length. FTIR spectroscopy experiments revealed an ordered hydrogen bonding carbonyl stretching band for each copolymer and as the spacing between oxamide groups increased, the temperature at which the hard segment order was disrupted decreased. The increased spacing between oxamide groups also led to a decrease in the flow temperature observed with dynamic mechanical analysis. Copolymer tensile properties decrease with increased oxamide spacing as well as the hysteresis. The structure-property investigations of PDMS poly(oxamide) segmented copolymers showed that the shortest oxamide spacing resulted in materials with optimal mechanical properties. A new class of non-chain extended segmented copolymers that contained both urea and oxamide hydrogen bonding groups in the hard segment were synthesized. PDMS poly(urea oxamide) (PDMS-UOx) copolymers displayed thermoplastic elastomer behavior with enhanced physical properties compared to PDMS polyurea (PDMS-U) controls. Synthesis of a difunctional oxamic hydrazide terminated PDMS oligomer through a two-step end capping procedure with diethyl oxalate and hydrazine proved highly efficient. Solution polymerization of the oxamic hydrazide PDMS oligomers with HMDI afforded the desired PDMS-UOx segmented copolymer, which yielded optically clear, tough elastomeric films. Dynamic mechanical analysis showed a large temperature insensitive rubbery plateau that extended up to 186 ÚC for PDMS-UOx copolymers and demonstrated increased rubbery plateau ranges of up to 120 ÚC when compared to the respective PDMS-U control. The increase in thermomechanical properties with the presence of oxamide groups in the hard segment was due to the increased hydrogen bonding, which resulted in a higher degree of microphase separation. DMA, SAXS, and AFM confirmed better phase separation of the PDMS-UOx copolymers compared to PDMS-U controls and DSC and WAXD verified the amorphous character of PDMS-UOx. Oxamide incorporation showed a profound effect on the physical properties of PDMS-UOx copolymers compared to the controls and demonstrated promise for potential commercial applications. Two novel segmented copolymers based on a poly(propylene glycol) (PPG) that contained two or three oxamide groups in the hard segment were synthesized. Synthesis of non-chain extended PPG poly(trioxamide) (PPG-TriOx) and PPG poly(urea oxamide) (PPG-UOx) segmented copolymers utilized the two-step end-capping procedure with diethyl oxalate and hydrazine then subsequent polymerization with oxalyl chloride or HMDI, respectively. The physical properties of the PPG-TriOx and PPG-UOx copolymers were compared to those of PPG poly(urea) (PPG-U) and poly(oxamide) (PPG-Ox) copolymers. FTIR studies suggested the presence of an ordered hydrogen bonded hard segment for PGG-TriOx and PPG-Ox copolymers with PPG-TriOx possessing a lower energy ordered hydrogen bonding structure. PPG-UOx copolymers exhibited a larger rubbery plateau and higher moduli compared to PPG-U copolymers and also a dramatic increase in the tensile properties with the increased hydrogen bonding. The described copolymers provided a good example of the utility of this new step-growth polymerization chemistry for producing segmented copolymers with strong hydrogen bonding capabilities. Non-viral nucleic acid delivery has become a hot field in the past 15 years due to increased safety, compared to viral vectors, and ability to synthetically alter the material properties. Altering a synthetic non-viral delivery vector allows for custom tailoring of a delivery vector for various therapeutic applications depending on the target disease. The types of non-viral delivery vectors are diverse, however the lack of understanding of the endocytic mechanisms, endosomal escape, and nucleic acid trafficking is not well understood. This lack of understanding into these complex processes limits the effective design of non-viral nucleic acid delivery vehicles to take advantage of the cellular machinery, as in the case of viral vectors. Mechanisms for cellular internalization of polymer-nucleic acid complexes are important for the future design of nucleic acid delivery vehicles. It is well known that the mammalian cell surface is covered with glycosaminoglycans (GAG) that carry a negative charge. In an effort to probe the effect of GAG charge density on the affinity of cationic poly(glcoamidoamine) (PGAA)-pDNA complexes, quartz crystal microbalance was employed to measure the mass of GAGs that associated with a polyplex monolayer. Affinity of six different GAGs that varied in the charge density were measured for polyplexes formed with poly(galactaramidopentaethylenetetramine) (G4) cationic polymers and pDNA. Results showed that the affinity of GAGs for G4 polyplexes was not completely dependent on the electrostatic interactions indicating that other factors contribute to the GAG-polyplex interactions. The results provided some insight into the interactions of polyplexes with cell surface GAGs and the role they play in cellular internalization. Two adamantane terminated polymers were investigated to study the non-covalent inclusion complexation with click cluster non-viral nucleic acid delivery vehicles for passive targeting of the click cluster-pDNA complexes (polyplex). Incorporation of adamantyl terminated poly(ethylene glycol) (Ad-PEG) and poly(2-deoxy-2-methacrylamido glucopyranose) (Ad-pMAG) polymers into the polyplex formulation revealed increased colloidal stability under physiological salt concentrations. Ad-pMAG polyplexes resulted in lower cellular uptake for HeLa cells and not two glioblastoma cell lines indicating the pMAG corona imparts some cell line specificity to the polyplexes. Ad-pMAG provided favorable biological properties when incorporated into the polyplexes as well as increased polyplex physical properties. / Ph. D.

L’apparition de métastases est souvent le signe d’un mauvais pronostic vital pour les personnes atteintes d’un cancer. Ce processus de formation de métastase est un phénomène complexe dans lequel la migration cellulaire est un facteur clé.De récentes études ont montré que le canal SK3 (canal potassique de faible conductance dont l’activité dépend de la concentration cytosolique en calcium) était exprimé dans des cellules cancéreuses à fort pouvoir métastatique et leur conférait des capacités de migration accrues. Cette protéine constitue donc une nouvelle cible thérapeutique très intéressante pour agir sur la dissémination de cellules cancéreuses.Les objectifs de ces travaux de thèse ont permis de mettre en oeuvre deux stratégies visant à inhiber l’activité de ce canal potassique SK3.L’édelfosine, un glycérolipide à tête phosphocholine, a rapidement été reconnue comme étant un inhibiteur efficace de l’activité de ce canal. Cependant les effets secondaires induits par cette molécule ont conduit à rechercher des analogues moins toxiques et tout aussi efficaces. Des études structures-activité menées au sein du laboratoire ont permis de développer un nouveau glycérolipide à tête lactose, l’ohmline. Dans le but de compléter cette étude, nous avons réalisé la synthèse de glyco-glycérolipides et de glycophospho-glycérolipides et avons montré leur capacité à inhiber la protéine SK3 et à réduire la migration cellulaire SK3 dépendante.Une seconde stratégie vise à l’utilisation possible d’ARN interférents pour bloquer l’expression de la protéine SK3. Dans ce but, nous nous sommes intéressés à la synthèse et à l’incorporation, dans des formulations de lipides cationiques utilisés pour la transfection, de lipides neutres portant des motifs anisamides, ligands spécifiques des récepteurs sigma surexprimés dans des lignées cellulaires de tumeurs exprimant SK3. La synthèse de lipophosphoramides comportant un motif anisamide est présentée suivie de leur utilisation dans des expériences de transfection modèles (vectorisation d’ADN plasmidique) afin d’évaluer l’efficacité du ciblage engendré par le motif anisamide. / The occurrence of metastasis in a cancer is generally associated to a bad prognostic for the patient. The formation of metastasis is the result of a complex process in which cell migration plays a key role.Recent studies have shown that the potassium calcium-dependent channel SK3 is expressed in several highly metastatic cancerous cell lines and play a direct role in the migration process. Consequently, this protein is an interesting new therapeutic target to reduce metastasis formation.This PhD thesis work aimed investigating two strategies to reduce SK3 dependent cell migration.Edelfosine, a glycerolipid with a phosphocholine head, was identified as an efficient inhibitor of the SK3 channel activity. However the side effects induced by this molecule (toxicity) led to look for efficient and less toxic analogues. Accordingly, structure-activity studies carried out in our laboratory produced new glyco-glycerolipid including one with a lactose group (ohmline). With the aim of completing this study, we report the synthesis of glyco-glycerolipids and glycophospho-glycerolipids and shown their capacity to inhibit activity of SK3 channel.The second part of this work aims to act at an early stage by using RNAi to block the expression of the SK3 protein. In this way, we have synthesized and formulated, with a cationic lipid used for the transfection, neutral co-lipids functionalized with an anisamide moiety; this motif being recognize sigma receptors which are overexpressed in tumor cell lines that also expressed SK3. First, the synthesis of the lipophosphoramides with an anisamide moiety was described followed by their use in standard transfection experiments (plasmid DNA) to evaluate the effectiveness of the targeting strategy induced by the anisamide moiety.

Um problema recorrente no desenvolvimento de vacinas de DNA e terapia gênica utilizando vetores não virais é a baixa eficiência de transfecção gênica. Isso ocorre devido às diversas barreiras físicas, enzimáticas e difusionais que o DNA precisa superar para chegar ao núcleo das células. Neste trabalho tem-se por objetivo o desenvolvimento de novos vetores não virais de entrega gênica, formados por DNA plasmidial (pDNA), proteínas (protamina ou T-Rp3) e nanopartículas de ouro (NPAu) na forma de complexos ternários. Para tal, NPAu\'s foram sintetizadas por redução com citrato de sódio, apresentando diâmetros entre 20,3 e 57,3 nm e potencial zeta entre -69,0 e +43,3 mV, dependendo das condições de síntese, a saber, das quantidades de citrato de sódio adicionadas e da ordem de adição dos reagentes. Em seguida, vetores compostos por pDNA-protamina/T-Rp3-NPAu foram formados, transfectados em células HeLa cultivadas in vitro, e a atividade da enzima repórter luciferase foi medida. Deste modo, a partir de variações em proporção mássica e tamanho de nanopartículas, foi possível obter complexos utilizando protamina e ouro com uma eficiência de transfecção 33 vezes melhor do que transfecções utilizando apenas protamina. Por outro lado, complexos contendo T-Rp3 e ouro se mostraram ainda mais eficazes na entrega, apresentando níveis de transfecção próximos ao do reagente comercial Lipofectamina. Ensaios de transfecção utilizando a droga nocodazol indicaram a importância dos microtúbulos no mecanismo de entrega gênica, e ensaios com a droga cloroquina evidenciaram que as nanopartículas de ouro atuam de maneira diferenciada no escape endossomal dos vetores não virais utilizados. Visando relacionar características físico-químicas com a eficiência de transfecção, alguns destes complexos foram caracterizados por espalhamento dinâmico de luz, em que complexos com protamina apresentaram tamanhos entre 116 e 363 nm e complexos com T-Rp3 apresentaram entre 135 e 307 nm e potenciais zeta entre +7,3 e +22,5 mV e +10,6 e +27,2 mV, respectivamente, dependendo das características das NPAu\'s. / A recurrent problem in the development of DNA vaccines and gene therapy using non-viral vectors is the low efficiency of transfection. That is due to the many physical, enzymatic and diffusional barriers that DNA must overcome to reach the cell nucleus. This work aims to develop novel non-viral vectors based on plasmid DNA (pDNA), proteins (protamine or recombinant T-Rp3) and gold nanoparticles (AuNP) as ternary complexes. For such, AuNP\'s were first synthesized via sodium citrate reduction, with diameters varying from 20,3 to 57,3 nm and zeta potentials between -69,0 and +43,3 mV, depending on synthesis conditions, changing the quantities of sodium citrate added and the order of addition of reagents. Vectors formed by pDNA-protamine/T-Rp3-AuNP were then formed, transfected and luciferase activity was measured. Thus, from variations on mass ratios and gold nanoparticle sizes, it was possible to obtain complexes with protamine and gold with a transfection efficiency 33 times higher than analog complexes using only protamine. Also, complexes containing T-Rp3 and gold showed an even higher delivery efficiency, with transfection efficiency close to Lipofectamine. Assays using nocodazole indicated the importance of microtubule in the gene delivery process and, whereas assays with chloroquine showed that gold nanoparticles act in a different way over endossomal escape of used non-viral vectors. Finally, some of these complexes were characterized with dynamic light scattering. Complexes with protamine were within the size ragne of 116 to 363 nm and complexes with T-Rp3 were within the size range of 135 to 307 nm. The zeta potential varied from +7,3 to +22,5 mV and from +10,6 to +27,2 mV, respectively, depending on the gold nanoparticles used.

Um dos principais limitantes do desenvolvimento de protocolos eficientes de terapia gênica e vacinação com DNA provém da baixa eficiência de transferência gênica por parte dos vetores não-virais. Isso surge, principalmente, pela dificuldade de transporte de DNA estrangeiro do exterior para o núcleo das células alvo, devido à presença de inúmeras barreiras. O principal objetivo do trabalho realizado foi o desenvolvimento e caracterização de novos vetores não virais multifuncionais, capazes de realizar eficientemente a entrega de material genético (DNA plasmidial, pDNA) ao núcleo de células de mamífero (HeLa). Para esse fim, complexos binários (CBs) foram formados combinando-se pDNA à protamina ou proteínas recombinantes (TRP3) anteriormente desenvolvidas por nosso grupo. Foi também estudado o encapsulamento destes CBs em lipossomas catiônicos, formados pelos lipídios EPC:DOPE:DOTAP, gerando então complexos pseudo-ternários (CPTs). Os estudos com a protamina revelaram que os CPTs formados apresentavam tamanhos relativamente pequenos (< 123 nm) e com valores de potencial zeta, variando de +22,8 mV a +36,3 mV, nas várias relações mássicas (pDNA:protamina) estudadas (1:0,5; 1:0,7, 1:0,9 e 1:1). Os ensaios de transfecção mostraram que o CPT na relação 1:0,5 (CB) obteve o melhor nível de transfecção das células (17,1%) com um nível de viabilidade celular de 73,2%. Os ensaios utilizando a TRP3 mostraram que os CPTs formados adquiriram tamanhos pequenos (< 134 nm) e valores de potencial zeta entre +36,8 mV e +11,9 mV dependendo da relação mássica do CB (1:1, 1:30 e 1:60). Os ensaios de transfecção mostram que os CPTs formados com a TRP3 aumentaram o nível de transfecção em todas as relações de pDNA-TRP3 usadas (1:1; 1:30 e 1:60). Vale ressaltar que nas relações mássicas 1:30 e 1:60 houve um aumento significativo na transfecção (25,2% e 24,5%, respectivamente). Os ensaios de citotoxicidade mostram que os CBs não afetaram a viabilidade célular, entretanto quando combinada ao lipossoma foi observado aumento da citotoxicidade. Finalmente, os resultados indicam que a TRP3 associada ao lipossoma (CPTs) aumenta a eficiência de entrega de pDNA sugerindo um efeito sinérgico entre essas duas moléculas na superação das várias barreiras físicas, químicas e difusionais encontradas na célula. / One of the major challenges on the development of efficient protocols for gene therapy and DNA vaccination is the low efficiency of gene transfer by non viral vectors. This is mainly attributed to the fact that, during the traffic to target cells nuclei, plasmid vectors must overcome a series of physical, enzymatic and diffusional barriers. The objective of this work was the development and characterization of new multifunctional non-viral vectors, based on lipids and proteins, able to delivery efficiently the foreign pDNA (plasmid DNA) to the nucleus of mammalian cells. A model pDNA containing the reporter gene GFP was complexed to protamine or the recombinant protein (TRP3), forming binary complexes (BC). In addition, we studied the ability of the cationic liposomes (EPC:DOPE:DOTAP) to encapsulate this binary complexes to form pseudo-ternary complexes (PTCs). The studies of size (DLS) and zeta potential revealed that both proteins were able to condense pDNA to form small complexes (BCS and PTCs) (~100 nm) and positively charged (+11,9 mV a +36,8 mV), both interesting characteristics for transfections. However, the CPTs formed by TRP3 was that showed the highest transfections level (25,3%). The cytotoxicity assays indicated the BCs had a low effect on the cell viability. On the other hand, the biggest effect on cell death was found when PTCs were used. The results indicated the TRP3 associated to liposomes (PTCs) increased the delivery efficiency due to differences in the intracellular trafficking, suggesting a synergic effect between these different molecules in the vector in order to overcome the barriers found inside the cell.

Em estudos de terapia gênica e vacinação por DNA, a eficiência e a segurança dos vetores que transportam o material genético terapêutico possuem papel fundamental. Vetores não virais são considerados mais seguros, mas menos eficientes em relação aos vetores virais. Em parte, isso se deve à falta de estudos sistemáticos e comparativos no que diz respeito às características físico-químicas desses vetores quando em soluções biológicas e o efeito delas sobre a eficiência de entrega gênica. O objetivo deste trabalho é avaliar o efeito do pH, da força iônica e do tipo tampão de complexação sobre as características físico-químicas de nanopartículas pDNA-protamina e pDNA-protamina-lipofectamina, visando à entrega gênica para diferentes linhagens celulares. Para isso, nanopartículas formadas em diferentes condições foram caracterizadas através de ensaios de espalhamento dinâmico de luz (DLS) e potencial zeta. Os estudos indicaram que o pH, a força iônica, o tipo de tampão e a presença de meio de cultura e soro no ambiente de complexação alteram significativamente o tamanho, a polidispersidade e o potencial zeta das partículas formadas. Finalmente, buscou-se avaliar o efeito dessas características sobre a eficiência de transfecção in vitro de células de macrófagos IC21 e células HeLa. Os estudos de transfecção em células Hela indicam que tanto a composição como as condições de formação das partículas influenciam significativamente a eficiência de transfecção. / In gene therapy and DNA vaccination studies, the efficiency and safety of the vector carrying the therapeutic gene play a fundamental role. Non-viral vectors are considered safer but less effective when compared to viral vectors. In part, this is due to the lack of systematic and comparative studies regarding the physicochemical characteristics of these vectors when prepared in biological solutions and their effect on gene delivery efficiency. The objective of this study was to evaluate the effect of pH, ionic strength and type of complexation buffer on pDNA-protamine and pDNAprotamine- lipofectamine nanoparticles aiming at gene delivery to different cell lines. In order to achieve this goal, nanoparticles formed under different conditions were characterized by dynamic light scattering test (DLS) and zeta potential. Our studies indicated that the pH, the ionic strength, buffer type, and the presence of culture medium and serum in the complexation environment all significantly affect the size, polydispersity, and zeta potential of the particles formed. Finally, we evaluated the effect of these characteristics on the efficiency of transfection in vitro using HeLa cells and macrophages IC21. The transfection studies, especially using Hela cells, indicated that both, nanoparticle composition and the conditions of complex formation, significantly affect the efficiency of the transfections.

Um dos principais limitantes ao desenvolvimento e aprovação para utilização em humanos das vacinas de DNA é a falta de um vetor ideal de entrega gênica, que seja ao mesmo tempo eficiente e seguro. Embora mais seguros, os vetores não virais enfrentam uma série de barreiras físicas, enzimáticas e difusionais que limitam a chegada do transgene ao núcleo das células alvo. Dando continuidade ao trabalho desenvolvido em nosso grupo de pesquisa, o principal objetivo desta dissertação de mestrado foi avaliar o desempenho do vetor não viral comercial Lipofectamina e da proteína multifuncional T-Rp3 na entrega do gene da glicoproteína do vírus da raiva (RVGP) a células BHK-21. Primeiramente, o gene RVGP foi inserido no plasmídeo modelo pVAX1. Foram então realizados estudos de transfecção em células BHK-21 (Baby Hamster Kidney), utilizando-se Lipofectamina como agente de transfecção, no sentido de constatar a correta expressão do gene RVGP contido no novo plasmídeo. Como controle positivo, foi utilizado o plasmídeo pCMV-RVGP. Os estudos de PCR quantitativo da transcrição reversa (qRT-PCR) e imunofluorescência indicaram a expressão da glicoproteína pelo pVAX1RVGP, ainda que em valores de expressão menores se comparados com o plasmídeo controle pCMV-RVGP. Foi também desenvolvido com sucesso um método quantitativo de determinação da expressão da RVGP em células utilizando-se citometria de fluxo, que confirmou os resultados anteriores. Devido ao plasmídeo pVAX1RVGP ter apresentado baixa eficiência de expressão da RVGP, buscou-se a elevação da eficiência a partir da adição da sequência de KOZAK no plasmídeo pVAX1RVGP. Nesse caso, ainda que os resultados indiquem um aumento na expressão, não houve confirmação estatística (p<0,05). Os estudos de entrega com a proteína T-Rp3 foram realizados com um lote da T-Rp3 armazenada em ultrafreezer. A proteína demonstrou-se não ser estável após o congelamento em nitrogênio líquido e armazenamento em ultrafreezer pelo tempo de 10 meses. Apesar de ser capaz de complexar o pDNA após esse tempo, não foi eficiente em ensaios de transfecção, tendendo a agregar em relações molares altas e ausência de soro fetal bovino. / One of the major bottlenecks on the development and approval of DNA vaccines in humans is the lack of an ideal gene delivery vector, which must be safe and efficient at the same time. Although safer, the non-viral vectors face a series of physical, enzymatic and diffusion barriers that limits the arrival of the endogenous gene in the nuclei of the target cells. The main goal of this work was the evaluation of the performances of the commercial non-viral vector Lipofectamine, and the recombinant protein T-Rp3, a multifunctional protein, on the delivery of the rabies virus glycoprotein (RVGP) gene to BHK-21 cells. First, the RVGP gene was inserted into the pVAX1 plasmid, and transfections using BHK-21 (Baby Hamster Kidney) cells were performed using the Lipofectamine reagent to verify the correct expression of the RVGP gene present in the new plasmid. As a positive control, the plasmid pCMV-RVGP was used. The quantitative reverse transcription (qRT-PCR) and immunofluorescence studies indicated the expression of RVGP from pVAX1RVGP, although in lower expression values in comparison to the control plasmid. In addition, a flow cytometry quantitative method to quantify and compare the expression of the RVGP in the membrane of the transfected cells was developed, confirming the previous results. With the purpose of increase, the expression of RVGP, the KOZAK consensus sequence was added to the new pVAX1RVGP plasmid, and despite of the apparent increase of RVGP expression, this could not be confirmed statistically. The experiments of gene delivery using the T-Rp3 protein were performed using a protein batch storaged in ultrafreezer for 10 months. However, the protein has shown not being stable after storage for this long period. Moreover, despite of being capable to complex pDNA after this time, T-Rp3 was not efficient in the transfection assays and tended to aggregate in high molar ratios.

Um dos principais limitantes ao desenvolvimento e aprovação para utilização em humanos das vacinas de DNA é a falta de um vetor ideal de entrega gênica, que seja ao mesmo tempo eficiente e seguro. Embora mais seguros, os vetores não virais enfrentam uma série de barreiras físicas, enzimáticas e difusionais que limitam a chegada do transgene ao núcleo das células alvo. Dando continuidade ao trabalho desenvolvido em nosso grupo de pesquisa, o principal objetivo desta dissertação de mestrado foi avaliar o desempenho do vetor não viral comercial Lipofectamina e da proteína multifuncional T-Rp3 na entrega do gene da glicoproteína do vírus da raiva (RVGP) a células BHK-21. Primeiramente, o gene RVGP foi inserido no plasmídeo modelo pVAX1. Foram então realizados estudos de transfecção em células BHK-21 (Baby Hamster Kidney), utilizando-se Lipofectamina como agente de transfecção, no sentido de constatar a correta expressão do gene RVGP contido no novo plasmídeo. Como controle positivo, foi utilizado o plasmídeo pCMV-RVGP. Os estudos de PCR quantitativo da transcrição reversa (qRT-PCR) e imunofluorescência indicaram a expressão da glicoproteína pelo pVAX1RVGP, ainda que em valores de expressão menores se comparados com o plasmídeo controle pCMV-RVGP. Foi também desenvolvido com sucesso um método quantitativo de determinação da expressão da RVGP em células utilizando-se citometria de fluxo, que confirmou os resultados anteriores. Devido ao plasmídeo pVAX1RVGP ter apresentado baixa eficiência de expressão da RVGP, buscou-se a elevação da eficiência a partir da adição da sequência de KOZAK no plasmídeo pVAX1RVGP. Nesse caso, ainda que os resultados indiquem um aumento na expressão, não houve confirmação estatística (p<0,05). Os estudos de entrega com a proteína T-Rp3 foram realizados com um lote da T-Rp3 armazenada em ultrafreezer. A proteína demonstrou-se não ser estável após o congelamento em nitrogênio líquido e armazenamento em ultrafreezer pelo tempo de 10 meses. Apesar de ser capaz de complexar o pDNA após esse tempo, não foi eficiente em ensaios de transfecção, tendendo a agregar em relações molares altas e ausência de soro fetal bovino. / One of the major bottlenecks on the development and approval of DNA vaccines in humans is the lack of an ideal gene delivery vector, which must be safe and efficient at the same time. Although safer, the non-viral vectors face a series of physical, enzymatic and diffusion barriers that limits the arrival of the endogenous gene in the nuclei of the target cells. The main goal of this work was the evaluation of the performances of the commercial non-viral vector Lipofectamine, and the recombinant protein T-Rp3, a multifunctional protein, on the delivery of the rabies virus glycoprotein (RVGP) gene to BHK-21 cells. First, the RVGP gene was inserted into the pVAX1 plasmid, and transfections using BHK-21 (Baby Hamster Kidney) cells were performed using the Lipofectamine reagent to verify the correct expression of the RVGP gene present in the new plasmid. As a positive control, the plasmid pCMV-RVGP was used. The quantitative reverse transcription (qRT-PCR) and immunofluorescence studies indicated the expression of RVGP from pVAX1RVGP, although in lower expression values in comparison to the control plasmid. In addition, a flow cytometry quantitative method to quantify and compare the expression of the RVGP in the membrane of the transfected cells was developed, confirming the previous results. With the purpose of increase, the expression of RVGP, the KOZAK consensus sequence was added to the new pVAX1RVGP plasmid, and despite of the apparent increase of RVGP expression, this could not be confirmed statistically. The experiments of gene delivery using the T-Rp3 protein were performed using a protein batch storaged in ultrafreezer for 10 months. However, the protein has shown not being stable after storage for this long period. Moreover, despite of being capable to complex pDNA after this time, T-Rp3 was not efficient in the transfection assays and tended to aggregate in high molar ratios.

Em estudos de terapia gênica e vacinação por DNA, a eficiência e a segurança dos vetores que transportam o material genético terapêutico possuem papel fundamental. Vetores não virais são considerados mais seguros, mas menos eficientes em relação aos vetores virais. Em parte, isso se deve à falta de estudos sistemáticos e comparativos no que diz respeito às características físico-químicas desses vetores quando em soluções biológicas e o efeito delas sobre a eficiência de entrega gênica. O objetivo deste trabalho é avaliar o efeito do pH, da força iônica e do tipo tampão de complexação sobre as características físico-químicas de nanopartículas pDNA-protamina e pDNA-protamina-lipofectamina, visando à entrega gênica para diferentes linhagens celulares. Para isso, nanopartículas formadas em diferentes condições foram caracterizadas através de ensaios de espalhamento dinâmico de luz (DLS) e potencial zeta. Os estudos indicaram que o pH, a força iônica, o tipo de tampão e a presença de meio de cultura e soro no ambiente de complexação alteram significativamente o tamanho, a polidispersidade e o potencial zeta das partículas formadas. Finalmente, buscou-se avaliar o efeito dessas características sobre a eficiência de transfecção in vitro de células de macrófagos IC21 e células HeLa. Os estudos de transfecção em células Hela indicam que tanto a composição como as condições de formação das partículas influenciam significativamente a eficiência de transfecção. / In gene therapy and DNA vaccination studies, the efficiency and safety of the vector carrying the therapeutic gene play a fundamental role. Non-viral vectors are considered safer but less effective when compared to viral vectors. In part, this is due to the lack of systematic and comparative studies regarding the physicochemical characteristics of these vectors when prepared in biological solutions and their effect on gene delivery efficiency. The objective of this study was to evaluate the effect of pH, ionic strength and type of complexation buffer on pDNA-protamine and pDNAprotamine- lipofectamine nanoparticles aiming at gene delivery to different cell lines. In order to achieve this goal, nanoparticles formed under different conditions were characterized by dynamic light scattering test (DLS) and zeta potential. Our studies indicated that the pH, the ionic strength, buffer type, and the presence of culture medium and serum in the complexation environment all significantly affect the size, polydispersity, and zeta potential of the particles formed. Finally, we evaluated the effect of these characteristics on the efficiency of transfection in vitro using HeLa cells and macrophages IC21. The transfection studies, especially using Hela cells, indicated that both, nanoparticle composition and the conditions of complex formation, significantly affect the efficiency of the transfections.

There exists a dire need for improved therapeutics to achieve predictable and effective bone regeneration. Non-viral gene therapy is a safe method that can efficiently transfect target cells, therefore is a promising approach to overcoming the drawbacks of protein delivery of growth factors. The goal of this study was to employ cost-effective biomaterials to deliver genetic materials (DNA or RNA) in a controlled manner in order to address the high cost issues, safety concerns, and lower transfection efficiencies that exist with protein and gene therapeutic approaches. To achieve our goal, we set several aims: 1) To assess the bone regeneration capacity of polyethylenimine (PEI)-chemically modified ribonucleic acid (cmRNA) (encoding bone morphogenetic protein-2 (BMP-2)) activated matrices, compared to PEI-plasmid DNA (BMP-2)-activated matrices. 2) To explore the osteogenic potential of cmRNA-encoding BMP-9, in comparison to cmRNA-encoding BMP-2. 3) To use collagen membranes as integral components of a guided bone regeneration protocol and to enhance the bioactivity of collagen membranes by incorporating plasmid DNA (pDNA) or cmRNA encoding bone morphogenetic protein-9 (BMP-9). 4) To test whether the delivery of pDNA encoding BMP-2 (pBMP-2) and fibroblast growth factor-2 (pFGF-2) together can synergistically promote bone repair in a leporine model of diabetes mellitus, a condition that is known to be detrimental to union. 5) To investigated whether there is a synergistic effect on bone regeneration following delivery of pBMP-2 and pFGF-2, insulin and/or vitamin D. These investigations together provided new insights regarding the appropriate treatment methods for patients with fractures. Here we develop and test a non-viral gene delivery system for bone regeneration in challenging animal models utilizing a scaffold carrying PEI-nucleic acid complexes. We utilized three kinds of pDNA encoding either BMP-2, BMP-9 or FGF-2 as well as two kinds of cmRNA encoding either BMP-2 or BMP-9 formulated into PEI complexes. The fabricated nanoplexes were assessed for their size, charge, in vitro cytotoxicity, and capacity to transfect human bone marrow stromal cells (BMSCs). The in vivo functional potency of different nanoplexes embedded in scaffolds was evaluated using a calvarial bone defect model in rats, diaphyseal long bone radial defects in a diabetic rabbit model and intramuscular implantation in a diabetic rat. The results indicate that our non-viral gene delivery system induced migration and differentiation of resident cells to enhance bone regeneration. Together these findings suggest that scaffolds loaded with non-viral vectors harboring cmRNA or pDNA encoding osteogenic proteins may be a powerful tool for stimulating bone regeneration with significant potential for clinical translation.