Non-viral delivery vectors have potential advantages over the viral systems that currently are used extensively for delivering therapeutic genes of interest. However, non-viral gene therapy has low efficiencies in vivo, in part due to the aggregation of the particles in the delivery system associated with serum proteins and other components of the blood. An effective technique for overcoming this problem to use PluronicTM block copolymers to cover the surfaces of the particles in the delivery system with polyethylene oxide, which decreases their charge density and reduces their interactions with the serum proteins. The objectives of this project were to characterize a Pluronic-gemini surfactant system to be used as non-viral vectors for gene therapy. Five Pluronics (L44, F68, F87, F108, and F127) were evaluated by studying their physiochemical properties, including particle size and zeta potential. Also, these systems were evaluated in OVCAR-3 cell culture for gene expression and cell viability. The in vitro systems showed small particle sizes (approximately 200 nm) for all Pluronics. The particle sizes in the systems were increased dramatically (up to 2000 nm) by adding dioleylphosphatidylethanolamine (DOPE) to the systems. The zeta potential of these systems shifted the negative zeta potential of DNA (-43 mV) to a positive value (+35 mV). The addition of DOPE had very little effect on zeta potential. The in vitro transfection efficiency in OVCAR-3 showed that all of the Pluronics were able to transfect OVCAR-3 at various DNA/gemini surfactant ratios. The highest transfection efficiency was obtained with Pluronics L44, F87 and F108. PluronicF127 demonstrated the lowest transfection efficiency among the five Pluronics. Adding DOPE did not improve the transfection efficiency in any of the pluronic-gemini surfactant systems. The viabilities of the cells in these systems were high, and there were greater than the positive control (Lipofectamine 2000). The greatest cell viability (about 60%) was observed when the DNA to gemini surfactant ratio was 1:2. After adding DOPE, the cell viability decreased in all of the Pluronics except for Pluronic F68. The results of this investigation indicated that Pluronic block copolymers can transfect OVCAR-3 cell cultures in vitro and that they had a low level of cytotoxicity.

Glaucoma is a group of optic nerve degenerative diseases, which leads to gradual and permanent vision loss. Recent developments in the field of gene therapy have proposed increasingly promising treatments for glaucoma, in the form of delivery of neuro-protective or neuro-regenerative genes to the retina. Despite these developments, there are concerns related to the biocompatibility and invasiveness of common gene delivery systems, since they are commonly mediated by viral gene carriers and invasive administration methods. Non-viral gene delivery systems offer a safe and increasingly efficient alternative to deliver therapeutic genes to the retina. An example of these systems is gemini-phospholipid nanoparticles (GL-NPs), which have been successfully used to deliver genes in similarly challenging anatomical settings, such as the skin. The objective of this thesis is to demonstrate the potential of GL-NPs, as candidate gene delivery vehicles for topically administered genes, targeted to the retina. The dicationic gemini surfactant, 12-7NH-12 was used, along with the helper lipids, 1, 2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE), and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), to prepare various types of GL-NPs, and assess their transfection efficiency in the rat retinal ganglion cell line (RGC-5). The transfection efficiency was evaluated using flow cytometry, as a function of several physical and chemical parameters of GL-NPs. These include a range of charge ratios (5:1 to 15:1 ????), helper lipid composition (several DOPE: DPPC ratios), order of assembly (plasmid-gemini + lipid versus gemini-lipid + plasmid), and manufacturing method of helper lipid vesicles (thin film versus high pressure homogenization method). Size and zeta (??) potential characterization of GL-NPs was carried out in parallel, using dynamic light scattering, to relate the physical parameters of GL-NPs to their respective transfection efficiency. A comprehensive toxicological evaluation was undertaken to assess the extent of GL-NP???s toxicity in RGC-5 cells, using the resazurin-based PrestoblueTM cell toxicity assay. Optimized GL-NPs were used to induce expression of the brain derived neurotrophic factor (BDNF) in RGC-5 cells, and were assessed in terms of their capacity to induce neurite outgrowth. Quantification of neurite outgrowth was carried out by measuring average neurite length in RGC-5 cells, by confocal microscopic imaging of immunostained neurites. Furthermore, confocal microscopic studies were carried out to assess the extent of GL-NP???s corneal permeation in a 3-D human corneal epithelial (HCE) model. A parallel toxicological evaluation was completed to ensure GL-NP???s biocompatibility with the corneal epithelial cells. Finally, GL-NP biodistribution pattern and gene transfer capacity was assessed in a mouse model, following topical and intravitreal administration. The transfection efficiency in RGC-5 cells, which ranged between 2.1 ?? 0.3% and 14.5 ?? 1.4%, was highly dependent on GL-NP???s charge ratio, helper lipid composition, order of assembly, and manufacturing technique. GL-NPs at 10:1 ???? charge ratio, assembled with homogenized DOPE (25%)-DPPC (75%) helper lipid vesicles, in the plasmid-gemini + lipid order, mediated the highest transfection efficiency in RGC-5 cells. These GL-NPs had a size of 222.8 ?? 4.2 nm and a ?? potential of +33.5??2.9 mV. Optimized GL-NPs were highly biocompatible with both RGC-5 and HCE model cells, with viability values ranging between 94.8 ?? 6 % to 100 ?? 3.4 %. Assessment of corneal permeation showed that GL-NPs were able to bind to the corneal epithelial surface and achieve a moderate permeation depth (35-40 ??m), following topical application in the HCE model. Intravitreal injection of the non-viral GL-NPs in mice has successfully led to their localization within the nerve fiber layer (NFL) of the retina. Finally, GL-NPs were non-invasively delivered to several anterior chamber tissues, including the limbus, the iris and conjunctiva, following topical administration. GL-NPs offer several advantageous features critical to topical and intravitreal ocular administration of gene carriers, including in vitro corneal binding and effective biodistribution following in vivo topical and intravitreal administration, high biocompatibility, and a highly tunable transfection efficiency. The current data presents 12-7NH-12 GL-NPs as a promising candidate for ocular gene therapy applications.

Monte Carlo simulations have been used in the past to investigate a variety of surfactant systems; however, there is little published literature for double-headed and gemini surfactants with asymmetric tails. We perform Larson-type Monte Carlo simulations of double-headed and gemini surfactant systems with asymmetric tails in two- and three-dimensions. The model predicts that the addition of a second head group to form a double-headed surfactant results in an increase in the critical micelle concentration (CMC) compared to a single-headed surfactant, in agreement with experiment. It also indicates that the placement of the second head group has an impact on the final CMC value. We study a series of gemini surfactants with asymmetric tails and find no change in the value of the CMC as the ratio of the lengths of the two tails increases. This is contrary to the only experimental study that found there was a slight decrease in the CMC as the ratio of the lengths of the two tails increases. We examine this difference in terms of the relatively small effect surfactant asymmetry has on value of the CMC and the fact that the model is capable of qualitatively reproducing the known dependence of the CMC on other architectural properties. This initial probe into systems of double-headed and gemini surfactants with asymmetric tails confirms many of the previously published findings and provides avenues for possible future research using Monte Carlo simulations.

Research on self-assembling gemini surfactants and other amphiphiles for potential gene delivery applications in research as well as in clinical practice, and as alternatives to viral gene delivery vectors, is beginning to focus more on structureactivity relationships to address the current low gene delivery efficiencies of amphiphiles. Some underlying structureactivity relations are beginning to emerge. But, as a better understanding of the factors that govern the transfection abilities of amphiphile molecules emerges, development of improved non-viral vectors with clinical potential may also emerge.<p> The research conducted for this thesis was aimed at the design, synthesis and in vitro investigation of gemini surfactants as one of a family of novel amphiphiles being investigated for gene therapeutic applications. The properties of these compounds can be controlled as well as allowed to vary naturally. Gemini surfactant-based gene delivery systems were prepared and characterized for transfer of Luciferase plasmid (pMASIA.Luc) to both COS-7 and PAM 212 cells. Characterization was accomplished using microscopy, dynamic light scattering (DLS) and zeta (ζ) potential analysis. In vitro gene expression and toxicities were evaluated in COS-7 cell and PAM 212 keratinocyte cultures.<p> The level of in vitro transfection in general was found to correlate strongly with the structure of the gemini surfactants. Among the 12-spacer-12 surfactants, incorporation of a pH-sensitive aza (N-CH3) group, which is also steric hindrance-imposing, in the spacer chain yielded increased transfection, particularly for the 12-7N-12 surfactant. In comparison, the incorporation of the more pH-sensitive imino (N-H) group in the 12-7NH-12 surfactant yielded the highest increase in transfection among the 12-spacer-12 surfactants. The deleterious effect of steric hindrance due to the aza group is more evident when comparing the transfection efficiency of 12-5N-12 (1 × aza, higher) vs. 12-8N-12 (2 × aza, lower transfection). Another highlighted structural feature is provided by the fact that both the 12-7NH-12 and 12-7N-12 surfactants had higher transfection efficiencies than 12-5N-12 and 12-8N-12 surfactants; the first pair has trimethylene spacing, which constitutes an optimal separation between nitrogen centres, while the second pair has shorter dimethylene spacings.<p> After expanding the structure of surfactants, transfection efficiencies were found to increase in response to increase in hydrocarbon tail length, but were much lower for surfactants with no amino functional groups, those that lacked the optimal trimethylene spacing, or those having both of these limitations in the gemini surfactant spacer. The 18-7NH-18 surfactant had the highest overall transfection in both COS-7 and PAM 212 cells. Gemini surfactant-based gene delivery systems capable of adopting both polymorphic structural phases and which could undergo pH-induced structural transition demonstrated high transfection efficiencies. Gemini surfactants with both characteristics (e.g., 12-7NH-12-based complexes are both polymorphic and pH-sensitive) had higher transfection than gemini surfactants with only one (e.g., 12-3-12-based complexes are only polymorphic).<p> Overall, the m-7NH-m surfactants, the most efficient surfactants studied, had transfection efficiencies similar to that of the commercial Lipofectamine Plus reagent and imposed no higher toxicity on cells relative to the less efficient surfactants. Thus, the design of the m-7NH-m surfactants to enhance their transfection abilities also ensured that their toxicity to cells were kept minimal. Overall, the design, synthesis and in vitro transfection screening of gemini surfactant candidates has revealed that the m-7NH-m surfactants have the highest transfection efficiencies; they have emerged as suitable candidates for non-viral gene delivery in vivo or at higher levels. Gene delivery investigations for six of the gemini surfactant candidates are being reported for the first time.

Research on self-assembling gemini surfactants and other amphiphiles for potential gene delivery applications in research as well as in clinical practice, and as alternatives to viral gene delivery vectors, is beginning to focus more on structureactivity relationships to address the current low gene delivery efficiencies of amphiphiles. Some underlying structureactivity relations are beginning to emerge. But, as a better understanding of the factors that govern the transfection abilities of amphiphile molecules emerges, development of improved non-viral vectors with clinical potential may also emerge.<p> The research conducted for this thesis was aimed at the design, synthesis and in vitro investigation of gemini surfactants as one of a family of novel amphiphiles being investigated for gene therapeutic applications. The properties of these compounds can be controlled as well as allowed to vary naturally. Gemini surfactant-based gene delivery systems were prepared and characterized for transfer of Luciferase plasmid (pMASIA.Luc) to both COS-7 and PAM 212 cells. Characterization was accomplished using microscopy, dynamic light scattering (DLS) and zeta (ζ) potential analysis. In vitro gene expression and toxicities were evaluated in COS-7 cell and PAM 212 keratinocyte cultures.<p> The level of in vitro transfection in general was found to correlate strongly with the structure of the gemini surfactants. Among the 12-spacer-12 surfactants, incorporation of a pH-sensitive aza (N-CH3) group, which is also steric hindrance-imposing, in the spacer chain yielded increased transfection, particularly for the 12-7N-12 surfactant. In comparison, the incorporation of the more pH-sensitive imino (N-H) group in the 12-7NH-12 surfactant yielded the highest increase in transfection among the 12-spacer-12 surfactants. The deleterious effect of steric hindrance due to the aza group is more evident when comparing the transfection efficiency of 12-5N-12 (1 × aza, higher) vs. 12-8N-12 (2 × aza, lower transfection). Another highlighted structural feature is provided by the fact that both the 12-7NH-12 and 12-7N-12 surfactants had higher transfection efficiencies than 12-5N-12 and 12-8N-12 surfactants; the first pair has trimethylene spacing, which constitutes an optimal separation between nitrogen centres, while the second pair has shorter dimethylene spacings.<p> After expanding the structure of surfactants, transfection efficiencies were found to increase in response to increase in hydrocarbon tail length, but were much lower for surfactants with no amino functional groups, those that lacked the optimal trimethylene spacing, or those having both of these limitations in the gemini surfactant spacer. The 18-7NH-18 surfactant had the highest overall transfection in both COS-7 and PAM 212 cells. Gemini surfactant-based gene delivery systems capable of adopting both polymorphic structural phases and which could undergo pH-induced structural transition demonstrated high transfection efficiencies. Gemini surfactants with both characteristics (e.g., 12-7NH-12-based complexes are both polymorphic and pH-sensitive) had higher transfection than gemini surfactants with only one (e.g., 12-3-12-based complexes are only polymorphic).<p> Overall, the m-7NH-m surfactants, the most efficient surfactants studied, had transfection efficiencies similar to that of the commercial Lipofectamine Plus reagent and imposed no higher toxicity on cells relative to the less efficient surfactants. Thus, the design of the m-7NH-m surfactants to enhance their transfection abilities also ensured that their toxicity to cells were kept minimal. Overall, the design, synthesis and in vitro transfection screening of gemini surfactant candidates has revealed that the m-7NH-m surfactants have the highest transfection efficiencies; they have emerged as suitable candidates for non-viral gene delivery in vivo or at higher levels. Gene delivery investigations for six of the gemini surfactant candidates are being reported for the first time.

For over a decade, diquaternary ammonium gemini surfactants have shown promise as non-viral gene delivery agents in both in vitro and in vivo systems. Their continued development, however, requires an understanding of their biological fate. The absence of identification and quantification methods that can achieve that goal is what drove the development of simple and rapid mass spectrometry (MS)-based methods; the focus of my Ph.D. dissertation. Prior to the development of these MS-based methods, an understanding of the gas phase behavior of diquaternary ammonium gemini surfactants is required. The development of a universal fragmentation pathway for gemini surfactants was achieved using low resolution and high resolution MS instruments. Single stage (MS), tandem stage (MS/MS and quasi-multi-stage (quasi MS3) mass spectrometry analysis allowed for the confirmation of the molecular composition and structure of each gemini surfactant through the identification of common and unique mass to charge values. Understanding the fragmentation behavior allowed for the specific identification and/or quantification of gemini surfactants by MS-based methods; including liquid chromatography low resolution tandem mass spectrometry (LC-LR-MS/MS), fast chromatography low resolution tandem mass spectrometry, fast chromatography high resolution mass spectrometry, desorption electrospray ionization low resolution mass spectrometry and matrix assisted laser desorption ionization high resolution mass spectrometry. We hypothesized that a LC-LR-MS/MS method would be the most effective quantitative method for the quantification of N,N-bis(dimethylhexadecyl)-1,3-propane-diammonium dibromide (G16-3) within PAM212 cellular lysate; achieving the lowest lower limit of quantification (LLOQ). Although the LC-LR-MS/MS method achieved a LLOQ suitable for analysis of G16-3 within PAM212 cell lysate, its limitations made it an inefficient method. In comparison, the four alternative mass spectrometry methods were faster, more efficient and less expensive than a conventional LC-LR-MS/MS method for the post transfection quantification of G16-3 within PAM212 cell lysate to be determined; 1.45 ± 0.06 μM. Future application of the universal fragmentation pathway and each MS-based quantification method will be beneficial for the future development of diquaternary ammonium gemini surfactants to further understand their post transfection fate.

Gene transfer represents an important advance in the treatment of both genetic and acquired diseases. Topical gene therapy involves administration of the genetic material onto the surface of skin and mucosal membranes. Cationic gemini surfactants (m-s-m, where m represents the carbon atoms in the alkyl tail and s represents the carbon atoms in the spacer) are a novel category of delivery agents with especially high potential for polynucleotides. This is due to their structural versatility, ability to bind and condense DNA, and relatively low toxicity. <p>The objectives were to design, construct and characterize a cationic, non-viral gemini surfactant-based delivery system for an IFN-ã coding plasmid suitable for cutaneous gene therapy and to evaluate this novel therapeutic approach in a Tsk (tight-skin scleroderma) mouse model to determine its clinical feasibility. <p>The delivery systems were characterized by microscopy, dynamic light scattering (DLS), circular dichroism (CD) and small angle X-ray scattering (SAXS). <i>In vitro</i> gene expression was evaluated in PAM 212 keratinocyte culture. The extent of topical delivery of the plasmid using nanoparticle and nanoemulsion formulations was evaluated by measuring IFN-ã levels in CD1, IFN-ã-deficient and Tsk mice. The effect of transgene expression on collagen synthesis was evaluated in Tsk animals by real-time PCR.<p>The <i>in vitro</i> plasmidgeminilipid (PGL) system showed heterogeneous particle size (100-200 nm small particles and 300-600 nm aggregates). Electrostatic interactions between the DNA and PGL systems shifted the negative æ-potential of the DNA (-47 mV) to positive values (30-50 mV). At the same time, condensation of the DNA, and formation of Ø DNA was indicated by the increase of the overall negative signal in the CD spectra, due to the flattening of the 290 nm peak and shift of the 260 nm peak into the negative region in a structure-dependent manner. Lipid organization of the DNADOPE system, in the absence of gemini surfactants, shows hexagonal structure, while addition of gemini surfactant at +/- charge ratio of 10 caused lamellar phase organization. For short spacers (n=3-6), additional Pn3m cubic phase also appear to be present. <p><i> In vitro</i> transfection efficiency in the 12-n-12 series was found to be dependent on the length of the spacer between the two positively charged head groups, with the n=3 spacer showing the highest activity. The PGL systems with 12-3-12 and 12-4-12 led to significantly higher transgene expression compared to the other surfactants of the series. The transfection efficiency significantly correlated with the surface area occupied by one molecule (a). The effect of the tail length influenced the transfection efficiency, with longer tails being associated with higher protein expression. The highest <i>in vitro</i> transfection efficiency was recorded with the 18:1-3-18:1 surfactant (1.4±0.3 ng/5x10E4 cells). <p><i>In vivo</i>, high levels of IFN-ã expression were detected in the skin of animals treated with both nanoparticle (359±239 pg/cm2) and nanoemulsion (607±411 pg/cm2) formulations compared to topical naked DNA (136±125 pg/cm2). IFN-ã levels in the skin of animals injected with 5 ìg DNA were 256±130 pg/cm2. IFN-ã levels in the lymph nodes were higher for the nanoparticle formulation (433±456 pg/animal) compared to nanoemulsion (131±136 pg/animal) suggesting different delivery pathway of the two formulations.<p>IFN-ã expression was at high levels in the skin of Tsk mice after 4-day and 20-day treatments (472±171 and 345±276 pg/cm2). Both 4-day and 20-day treatments reduced the procollagen type I á1 mRNA levels for the topical treatment (64 and 70% reduction) and intradermal injection (58 and 72% reduction). Intercellular adhesion molecule-1 (ICAM-1) was upregulated by 50% in both topically treated and injected animals after 20-day treatment. <p>Here, it has been demonstrated that cationic gemini surfactant-based delivery systems are able to transfect epidermal cells <i>in vivo</i>, and the transgene IFN-ã expression is sufficient to cause significant reduction of collagen in an animal model of scleroderma. It has been shown for the first time that topical gene therapy is a feasible approach for the modulation of excessive collagen synthesis in scleroderma-affected skin.

Gene transfer represents an important advance in the treatment of both genetic and acquired diseases. Topical gene therapy involves administration of the genetic material onto the surface of skin and mucosal membranes. Cationic gemini surfactants (m-s-m, where m represents the carbon atoms in the alkyl tail and s represents the carbon atoms in the spacer) are a novel category of delivery agents with especially high potential for polynucleotides. This is due to their structural versatility, ability to bind and condense DNA, and relatively low toxicity. <p>The objectives were to design, construct and characterize a cationic, non-viral gemini surfactant-based delivery system for an IFN-ã coding plasmid suitable for cutaneous gene therapy and to evaluate this novel therapeutic approach in a Tsk (tight-skin scleroderma) mouse model to determine its clinical feasibility. <p>The delivery systems were characterized by microscopy, dynamic light scattering (DLS), circular dichroism (CD) and small angle X-ray scattering (SAXS). <i>In vitro</i> gene expression was evaluated in PAM 212 keratinocyte culture. The extent of topical delivery of the plasmid using nanoparticle and nanoemulsion formulations was evaluated by measuring IFN-ã levels in CD1, IFN-ã-deficient and Tsk mice. The effect of transgene expression on collagen synthesis was evaluated in Tsk animals by real-time PCR.<p>The <i>in vitro</i> plasmidgeminilipid (PGL) system showed heterogeneous particle size (100-200 nm small particles and 300-600 nm aggregates). Electrostatic interactions between the DNA and PGL systems shifted the negative æ-potential of the DNA (-47 mV) to positive values (30-50 mV). At the same time, condensation of the DNA, and formation of Ø DNA was indicated by the increase of the overall negative signal in the CD spectra, due to the flattening of the 290 nm peak and shift of the 260 nm peak into the negative region in a structure-dependent manner. Lipid organization of the DNADOPE system, in the absence of gemini surfactants, shows hexagonal structure, while addition of gemini surfactant at +/- charge ratio of 10 caused lamellar phase organization. For short spacers (n=3-6), additional Pn3m cubic phase also appear to be present. <p><i> In vitro</i> transfection efficiency in the 12-n-12 series was found to be dependent on the length of the spacer between the two positively charged head groups, with the n=3 spacer showing the highest activity. The PGL systems with 12-3-12 and 12-4-12 led to significantly higher transgene expression compared to the other surfactants of the series. The transfection efficiency significantly correlated with the surface area occupied by one molecule (a). The effect of the tail length influenced the transfection efficiency, with longer tails being associated with higher protein expression. The highest <i>in vitro</i> transfection efficiency was recorded with the 18:1-3-18:1 surfactant (1.4±0.3 ng/5x10E4 cells). <p><i>In vivo</i>, high levels of IFN-ã expression were detected in the skin of animals treated with both nanoparticle (359±239 pg/cm2) and nanoemulsion (607±411 pg/cm2) formulations compared to topical naked DNA (136±125 pg/cm2). IFN-ã levels in the skin of animals injected with 5 ìg DNA were 256±130 pg/cm2. IFN-ã levels in the lymph nodes were higher for the nanoparticle formulation (433±456 pg/animal) compared to nanoemulsion (131±136 pg/animal) suggesting different delivery pathway of the two formulations.<p>IFN-ã expression was at high levels in the skin of Tsk mice after 4-day and 20-day treatments (472±171 and 345±276 pg/cm2). Both 4-day and 20-day treatments reduced the procollagen type I á1 mRNA levels for the topical treatment (64 and 70% reduction) and intradermal injection (58 and 72% reduction). Intercellular adhesion molecule-1 (ICAM-1) was upregulated by 50% in both topically treated and injected animals after 20-day treatment. <p>Here, it has been demonstrated that cationic gemini surfactant-based delivery systems are able to transfect epidermal cells <i>in vivo</i>, and the transgene IFN-ã expression is sufficient to cause significant reduction of collagen in an animal model of scleroderma. It has been shown for the first time that topical gene therapy is a feasible approach for the modulation of excessive collagen synthesis in scleroderma-affected skin.

Dans ce travail, nous nous sommes concentrés sur la création de nanostructures chirales optiquement actives en fabriquant des nanohélices de silice fluorescente afin d’obtenir des matériaux souple, nanométriques, optiquement actifs pour des applications en tant que matériaux nanophotoniques. Dans cette optique, des nanohélices de silice chirales ont été utilisées pour greffer et organiser des nanocristaux inorganiques fluorescents achiraux tels que des quantums dots, des chromophores, des molécules et des polymères fluorescents selon différentes approches. Ces hélices inorganiques ont été formées par procédé sol-gel en utilisant des auto-assemblages hélicoïdaux organiques de molécules amphiphiles (amphiphile gemini cationique, avec un contre-ion chiral le tartrate) en tant que modèles. Tout d'abord, la surface de la silice hélicoïdale a été fonctionnalisée par l’APTES afin de greffer des quantum dots inorganiques ZnS-AgInS2 possédant divers ligands. Dans la deuxième partie, le polymère de dérivé anthracénique fluorescent a été organisé par dépôt et adsorption à la surface de silice hélicoïdale. Afin d’étudier les propriétés chiroptiques, différentes caractérisations ont été réalisées telle que la spectroscopie du dichroïsme circulaire (CD) et celle de la luminescence circulairement polarisée (CPL).Le premier chapitre présente l’étude bibliographique sur différents systèmes d’auto-assemblage organiques chiraux et leurs propriétés chiroptiques. Les études sur la formation de systèmes auto-assemblés chiraux dans différentes conditions, leur morphologie structurale, les techniques de fabrication et leurs applications sont discutées suivies de l'utilisation de nanocristaux fluorescents, à savoir, les quantums dots (QD) et les polymères fluorescents achiraux sur lesquels les propriétés chiroptiques peuvent être obtenues et leurs applications dans les nanodispositifs optiques, les capteurs et la nano-photonique.Dans la première partie du deuxième chapitre, différentes techniques de caractérisation telles que le microscope électronique en transmission (TEM), le microscope électronique en transmission haute résolution (HRTEM), la microscopie confocale, la spectroscopie UV-Vis, celle de la fluorescence, du dichroïsme circulaire (CD) et de la luminescence circulairement polarisée (CPL) sont décrites. Dans la deuxième partie, la synthèse du gemini 16-2-16 ainsi que son mécanisme d'auto-assemblage, et sa transformation en réplica de silice par l'intermédiaire de la chimie sol-gel sont décrits. Ces nanohélices de silice sont fonctionnalisées par le 3-aminopropyltriéthoxysilane (APTES). Leur analyse est effectuée par analyse thermogravimétrique (TGA) et analyse élémentaire (EA).Dans le troisième chapitre, nous nous sommes concentrés sur la synthèse de QDs inorganiques ((ZnS)x-1(AgInS2)x) avec différentes compositions rapport molaire et leurs caractérisations par TEM, TGA, EA, spectroscopie infrarouge à transformée de Fourier (FTIR), mesures de potentiel zêta, spectroscopie d'absorption et d'émission. Quatre types de ligands ont été utilisés, par échange de ligand, pour recouvrir les QDs : sulfure d'ammonium (AS), acide 3-mercaptopropionique (MPA), l-cystéine (L-Cys) et l'oleylamine (OLA). Ces QDs sont greffés à la surface des hélices de silice modifiée par de l’amine suite à des interactions ioniques. Diverses techniques ont été utilisées pour confirmer leur greffage à la surface des hélices de silice, et les propriétés optiques ont été étudiées par spectroscopie d'absorption et d'émission. Après le greffage, différents résultats ont été observés selon le ligand utilisé : la caractérisation par TEM montre que les QDs sont greffés à la surface des hélices de silice. [...] / In this work, we focused on the creation of optically active chiral nanostructures by fabricating fluorescent silica nanohelices in order to obtain optically active nanoscale soft materials for applications as nanophotonics materials. For this purpose, silica chiral nanohelices were used for grafting and organizing achiral fluorescent inorganic nanocrystals, dyes, molecules, and fluorescent polymers through different approaches. These inorganic helices were formed via sol-gel method using organic helical self–assemblies of surfactant molecules (achiral and cationic gemini surfactant, with chiral counterion, tartrate) as templates. First, the surface of helical silica was functionalized by APTES in order to graft inorganic quantum dots ZnS-AgInS2 with different capping ligands. In the second part, fluorescent anthracene derivative polymer was organized via deposition and absorption on the surface of helical silica. To investigate the chiroptical properties, circular dichroism and circularly polarised luminescence characterization were performed.In the first chapter, the bibliographic study on different chiral organic self-assembling systems and their chiroptical properties are shown. The studies on the formation of chiral self-assembled systems in different conditions, structural morphology, fabrication techniques and their applications are discussed followed by the use of fluorescent nanocrystals, i.e., quantum dots (QDs) and achiral fluorescent polymers on which chiroptical properties can be obtained and their applications in optical nanodevices, sensors, and nano-photonics.In the first part of the second chapter, different characterisation techniques such as transmission electron microscope (TEM) , high resolution transmission electron microscope (HRTEM), and confocal microscopy, UV-Vis spectroscopy and fluorescence spectroscopies, as well as circular dichroism (CD) and circularly polarised luminescence (CPL) spectroscopies are described. In the second part, the synthesis of Gemini 16-2-16 as well as their self-assemblies mechanism, and their transformation to silica replica via sol-gel chemistry are described. These silica nanohelices are functionalized by 3-aminopropyltriethoxysilane (APTES). Their analysis is performed by Thermogravimetric analysis (TGA) and elementary analysis (EA).In the third Chapter, we focused on the synthesis of inorganic ((ZnS)x-1(AgInS2)x) QDs with different compositions molar ratio and its characterizations by TEM, TGA, EA, Fourier-transform infrared spectroscopy (FTIR), zeta potential measurements, absorption, and emission spectroscopy. Four types of ligands were used to cap the QDs via phase ligand exchange as follows: ammonium sulphide (AS), 3-mercaptopropionic acid (MPA), l-cysteine (L-Cys) and the fourth one is oleylamine (OLA). These QDs are grafted on the surface of amine-modified silica helices through ionic interaction. Various techniques were used to show the grafting of QDs on the surface of silica helix, and their optical properties were studied using absorption and emission spectroscopy. After grafting, in each case of ligands, different results were observed as follows: The TEM characterization shows that QDs are grafted on the surface of silica helices. In the case of AS-capped QDs, the helical morphology of silica helices after grafting is destroyed; therefore the further ananlysis was not possible. While, in the cases of QDs with three other ligands MPA, OLA and L-cys, dense and homogeneous grafting of the QDs were observed by TEM and the helical morphology was preserved after their grafting. The HRTEM images were taken on the MPA-QDs@silica helices and energy-dispersive x-ray (EDX) analysis was performed in STEM mode, confirming the QDs elements present on the silica surfaces. [...]

En raison de leurs propriétés physiques uniques, les matériaux chiraux trouvent des applications aussi bien en physique, qu’en chimie ou biologie. Ici, nous nous intéressons à la synthèse de nanoobjets inorganiques chiraux et à leur utilisation en tant que systèmes nano-électromécaniques.Différents auto-assemblages à base de surfactants Gemini et de contre-ions chiraux (nucleotide ou tartrate) formant dans l’eau des hélices micrométriques et nanométriques sont étudiés. Ces auto-assemblages sont ensuite utilisés comme structures directrices pour la formation d’hélices de silice par transcription inorganique. Le contrôle de la réactivité du précurseur inorganique est crucial pour parvenir aux caractéristiques mécaniques souhaitées.Enfin, une minéralisation secondaire des nano-hélices avec du TiO2 et du ZnO a lieu afin de créer des matériaux fonctionnels aux propriétés électroniques ou piézoélectriques. Différentes approches de synthèse et l’optimisation des procédés sont présentées. / Due to their unique physical properties chiral materials are used in a wide range of applications in chemistry, physics and biology. In this work we focus on the fabrication of chiral functional materials for NanoElectroMechanical systems based on the inorganic transcription of self-assembled surfactants.At first we introduce a new Nucleoamphiphile based system that self-assembles into micrometer sized helical fibers in aqueous medium. The effect of a wide range of chemical and physical parameters on the morphology of the aggregates was investigated. Then the synthesis of chiral silica structures based on the organic micro- and nanohelices as templates was studied to achieve the required mechanical properties of the material. Control over the precursor reactivity is crucial for the transcription of the morphology of the template into the silica replica. Secondary mineralization with TiO2 or ZnO was performed to provide the necessary electrical properties and functionality to the chiral material. Different approaches and the optimization parameters are described in detail. Finally the measurement of the mechanical properties of the silica nanotubes and nanohelices by AFM as the first step of the NEMS development will be described.