O presente trabalho apresenta a síntese e a caracterização de derivados de quitosana, bem como o preparo e caracterização de filmes de nanocompósitos à base de quitosana comercial (ou seus derivados), argila (MMT) e nanopartículas de prata (NPs-Ag), obtidas via Fotoquímica. Para tanto, foram preparados, a partir da quitosana comercial (QC), os derivados: quitosana desacetilada (Q30des), quitosana purificada (QP), quitosanas parcialmente despolimerizas (QD30, QD21 e QD5), quitosanas hidrofílicas (QD21-40DEAE e QD5-49DEAE) e quitosanas anfifílicas (QD21-40DEAE-6DD, QD21-40DEAE-18DD, QD5-49DEAE-6DD e QD5-49DEAE-17DD). O grau médio de desacetilação das QC, QP e Q30des e de substituição por grupos DEAE e dodecila foram determinados por Espectroscopia de Ressonância Magnética Nuclear de Hidrogênio (RMN de 1H). Ademais, os biopolímeros foram caracterizados por Espectroscopia no Infravermelho (FTIR-ATR), Viscosimetria, Análise Termogravimétrica e Microscopia Eletrônica de Varredura (MEV). Em seguida, foi estudada a síntese de nanopartículas de prata, sob radiação UV, em filmes de nanocompósitos de quitosana comercial ou seus derivados e argila. Em um primeiro momento, estudou-se a formação das NPs-Ag em filmes de QC com diferentes formulações e posteriormente em filmes de derivados de quitosana contendo 10% de MMT (m/m). A técnica de Difração de Raios-X (DRX) foi utilizada para a determinação do espaçamento interlamelar da argila montmorilonita pura e nos compósitos preparados. A síntese das NPs-Ag foi acompanhada por Espectrofotometria de Absorção Molecular no UV-vis, e monitorada após um ano de sua formação, sendo suas características morfológicas, bem como a dispersão da argila nos nanocompósitos examinados por Microscopia Eletrônica de Transmissão (MET). Por fim, a atividade antimicrobiana dos filmes de nanocompósitos foi avaliada pelo método de Disco de Difusão contra as bactérias Escherichia coli e Bacillus subtilis. / The present work presents the synthesis and characterization of chitosan derivatives, as well as the preparation and characterization of nanocomposite films based on commercial chitosan (or its derivatives), clay (MMT) and silver nanoparticles (NPs-Ag) obtained by photochemical method. Therefore, were prepared from commercial chitosan (QC): deacetylated chitosan (Q30des); purified chitosan (QP); partially depolymerized chitosans (QD30, QD21 and QD5); hydrophilic chitosans (QD21-40DEAE and QD5-QD5) and amphiphilic chitosans (QD21-40DEAE-6DD, QD21-40DEAE-18DD, QD5-49DEAE-6DD and QD5-49DEAE-17DD). The deacetylation degrees of QC, QP and Q30des were determined by Nuclear Magnetic Resonance Spectroscopy (1H-NMR). This technique also used to determine the degrees of substitution by DEAE and dodecyl groups. In addition, the biopolymers were characterized by Infrared Spectroscopy (FTIR-ATR), Viscosimetry, Thermogravimetry and Scanning Electron Microscopy. Moreover, the NPs-Ag synthesis under UV radiation was studied on nanocomposite films of commercial chitosan or its derivatives and clay. At first, the Ag-NPs formation was studied on QC films with different formulations and secondarily, on films of chitosan derivatives containing 10 wt % of MMT. The X-Ray Diffraction (XRD) was used to determine the interlamellar spacing of pure montmorillonite clay and in the nanocomposites prepared. The synthesis of the NP-Ag was accompanied by UV-vis Spectroscopy. Its morphological characteristics, as well as the clay dispersion in the nanocomposites were examined by Electron Transmission Electron Microscopy (TEM). Finally, the antimicrobial activities of materials were investigated by the disk diffusion method against the bacteria Escherichia coli e Bacillus subtilis.

Les cellules dérivées de la moelle osseuse, principalement les cellules endothéliales progénitrices, sont réduites chez les patients souffrant de maladies cardiovasculaires. Leur mobilisation et leur incorporation aux sites de lésion vasculaire sont des évènements prépondérants dans l’accélération des processus de réendothélialisation. Dans un modèle murin, le 17β-estradiol favorise les processus de guérison vasculaire par la mobilisation et le recrutement des cellules endothéliales progénitrices dérivées de la moelle osseuse. Il existe présentement plusieurs stratégies afin d’augmenter la mobilisation des cellules progénitrices ainsi que leur incorporation à la paroi vasculaire. Cependant, peu d’études privilégient la livraison locale d’un nombre élevé de cellules progénitrices fonctionnelles par un véhicule biodégradable et leur maintien au site de lésion afin de favoriser la réendothélialisation ciblée. Un polymère d’intérêt pour cette application s’avère être le chitosan. Ce biopolymère non toxique et biodégradable est couramment utilisé dans l’ingénierie tissulaire et, depuis peu, est utilisé dans la guérison vasculaire. Le chitosan complexé à la phosphorylcholine voit sa solubilité s’accroître dans les solutions aqueuses ainsi que sa biocompatibilité cellulaire en condition physiologique. Le projet de ce mémoire visait donc : 1) à étudier in vitro, la capacité d’un polymère de chitosan complexé à la phosphorylcholine à influencer l’adhésion, la survie, la différenciation et la fonctionnalité cellulaire dans un modèle murin de culture mixte de cellules dérivées de la moelle osseuse et 2) de déterminer l’impact de la présence du 17β-estradiol sur ces mêmes comportements cellulaires. Nos travaux démontrent que la matrice de chitosan-phosphorylcholine s’avère compatible avec notre modèle de culture cellulaire. En effet, ce polymère est capable de promouvoir l’organisation et le développement des cellules dérivées de la moelle osseuse de façon comparable à la matrice normalement utilisée dans la croissance in vitro des cellules endothéliales progénitrices, la fibronectine. De plus, ce polymère n’a nullement compromis l’activité migratoire des cellules, laissant supposer qu’il pourrait éventuellement être un véhicule approprié pour effectuer une livraison cellulaire à un site de lésion. Il s’avère que le 17β-estradiol, lorsqu’ajouté au milieu de culture ou complexé au polymère de chitosan phosphorylcholine, est capable de moduler le comportement cellulaire, et ce, de façon différente. Le 17β-estradiol complexé au polymère de chitosan-phosphorylcholine démontre, par rapport à sa forme soluble, une plus grande aptitude à accroître le nombre de cellules hématopoïétiques ainsi que des cellules endothéliales progénitrices dérivées de la moelle osseuse in vitro. De plus, le 17β-estradiol complexé au polymère de chitosan-phosphorylcholine permet une amplification marquée des cellules endothéliales progénitrices et leur offre un support adéquat afin de favoriser la guérison vasculaire. L’ensemble de nos travaux suggère que le polymère de chitosan complexé à la phosphorylcholine en présence ou non de 17β-estradiol est une matrice compatible avec les cellules progénitrices dérivées de la moelle osseuse in vitro. Le 17β-estradiol complexé au polymère est toutefois plus efficace que sa forme soluble à promouvoir l’amplification du nombre de cellules progénitrices. Ce polymère représente un outil thérapeutique attrayant et une matrice de livraison d’agent bioactif prometteuse pour le recrutement cellulaire dans l’accélération de la guérison vasculaire. / Bone marrow derived cells, including endothelial progenitor cells, are reduced in numbers in patient with cardiovascular disease or risk factors. Mobilization and incorporation of these cells at the vascular lesion site are important events in the reendothelialization process. 17β-estradiol was shown in a mouse model of injury, to favour this healing process through mechanisms which involve the mobilization and incorporation of endothelial progenitor cells derived from the bone marrow. At the moment, there are many strategies to increase endothelial progenitor cells mobilization as well as recruitment into the vascular wall. However, few studies favour local delivery of a large number of functional progenitor cells on a biodegradable scaffold and to maintain them at the lesion site in order to promote reendothelialization. An interesting biopolymer for this application is chitosan. This non toxic and biodegradable biopolymer is commonly used in tissue engineering and was recently used in vascular healing. Phosphorylcholine modified chitosan can increase the water solubility and cell biocompatibility of the biopolymer in physiological condition. This master project was thus designed to :1) evaluate, in vitro, the capacity of phosphorylcholine modified chitosan to influence cell adhesion, survival, differentiation and functionality in a mouse model of bone marrow mixed culture and 2) determine the impact of 17β-estradiol on these cell behaviours. Our results suggest an adequate biocompatibility of phosphorylcholine modified chitosan with our cell culture system. Indeed, this polymer was able to promote cell organization and development of bone marrow derived cells in the same way that fibronectin, the most commonly matrix used in the progenitor cells in vitro culture. Moreover, cell migratory activity was not compromised by the chitosan polymer. It appears that 17β-estradiol, when added to cell culture media or attached on phosphorylcholine modified chitosan is able to modulate differently cell behaviour. Our data suggest that 17β-estradiol coupled to the chitosan polymer was superior to increase the number of haematopoietic and endothelial progenitor cells derived from bone marrow in vitro compared to the soluble form. 17β-estradiol coupled to the polymer of phosphorylcholine modified chitosan allowed an increased amplification of progenitor cell number and provided adequate scaffold to favour vascular healing. We propose that phosphorylcholine modified chitosan in presence or not of 17β-estradiol is a compatible matrix with bone marrow derived progenitor cells in vitro. 17β-estradiol enhances the amplification of progenitor cell in vitro when associated to the polymer compared to its soluble form. This biopolymer may be an attractive matrix and a promising vehicle in a drug delivery therapeutic system for progenitor cells recruitment and to promote vascular healing.

Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-04-04T20:09:37Z No. of bitstreams: 1 GLÓRIA TAMIRIS FARIAS DA SILVA FURTADO - DISSERTAÇÃO PPG-CEMat 2014..pdf: 2828132 bytes, checksum: 5e63edac512ab6bfb0b360a80afb5927 (MD5) / Made available in DSpace on 2018-04-04T20:09:37Z (GMT). No. of bitstreams: 1 GLÓRIA TAMIRIS FARIAS DA SILVA FURTADO - DISSERTAÇÃO PPG-CEMat 2014..pdf: 2828132 bytes, checksum: 5e63edac512ab6bfb0b360a80afb5927 (MD5) Previous issue date: 2014-08-28 / O câncer vem crescendo nas estatísticas da saúde pública, e o melanona é um dos tipos mais letais. Tem-se pesquisado substâncias que sejam menos tóxicas e que possam ser liberadas de forma controlada através de sistemas farmacêuticos. Para desenvolver os sistemas farmacêuticos utilizam-se materiais polímeros, os quais serão responsáveis pelo o controle de liberação da droga in situ desejado. A quitosana tem sido estudada por apresentar propriedades como atividade antimicrobiana, analgésico, pode ser modificada químicamente, fácil acesso e de baixo custo. O objetivo deste trabalho foi desenvolver e avaliar membranas de quitosana para o uso em sistemas de liberação controlada da curcumina para o tratamento de melanoma. As amostras foram preparadas pelo método de evaporação de solvente, utilizando uma solução de ácido acético (1% v/v), para obter uma solução de quitosana a 2% (m/v). As membranas de quitosana/curcumina foram obtidas a partir da dissolução da curcumina em etanol (1,2 mg/ml), vertendo-a na solução de quitosana, As membranas de quitosana com e sem curcumina, foram caracterizadas por FTIR, DRX, MEV, TG, DSC, GI, biodegradação enzimática, citotoxicidade (MCF-7), e como também realizado o desenvolvimento e validação do método analítico, e determinação do teor de curcumina na membrana desenvolvida. A partir das caracterizações ficou evidenciado que o método de processamento usado na obtenção da membrana quitosana/curcumina é adequado, tendo em vista que não houve degradação da curcumina. As membranas de quitosana/curcumina apresentaram menor intumescimento e degradação, e maior estabilidade quando comparadas às membranas de quitosana. Para o ensaio de citotoxicidade as membranas de quitosana/curcumina apresentaram potencial para o tratamento de câncer. O método analítico desenvolvido está conforme a RE Nº 899/2003 da ANVISA. Logo, o método utilizado foi adequado para identificação e quantificação da curcumina na membrana de quitosana/curcumina. Diante dos resultados obtidos, o sistema desenvolvido apresenta potencial para aplicações em liberação controlada de drogas. / The cancer is growing in public health statistics, and the melanoma is one of the most lethal types. Research has focused on substances that are less toxic and can be released in a controlled way through the developoment of pharmaceutical systems. To develop pharmaceutical systems are used polymer materials, which will be responsible for the drug release control in situ. Chitosan has been studied for having properties such as antimicrobial, analgesic, may be chemically modified, easy and inexpensive. The aim of this study was to develop and evaluate chitosan membranes for curcumin controlled release systems for treating melanoma. Samples were prepared by solvent casting, using a solution of acetic acid (1% v/v) to obtain a chitosan solution at 2% (w/v). The membranes of chitosan/curcumin was obtained from the dissolution of curcumin in ethanol (1.2 mg / ml) pouring the solution of chitosan, chitosan membranes with and without curcumin were characterized by FTIR, XRD, SEM, TG, DSC, SD, enzymatic degradation, cytotoxicity (MCF-7), and also performed as the development and validation of the analytical method, and determination of curcumin in membrane developed. From the characterizations became evident that the processing method used in obtaining the chitosan membrane/curcumin is appropriate, considering there was no degradation of curcumin. The membranes of chitosan/curcumin showed lower swelling ratio and degradation, and increased stability as compared to the chitosan membranes. For the cytotoxicity assay the membranes of chitosan/curcumin showed potential for the treatment of cancer. The developed analytical method is accordint to the ANVISA resolution No. RE 899/2003. Therefore, the method was suitable for identification and quantification of curcumin in chitosan/curcumin membranes. Based on these results, the system developed has potential for applications in controlled release of drugs.

Chitosan is a cationic natural polymer that is widely used as a topical dressing in wound management. Temporary coatings of removable denture bases with chitosan might be useful as supportive treatment in oral medicine. The aim of this study was to analyze the thickness, uniformity, and adhesive strength of chitosan coatings on simulated denture bases made from polymethyl methacrylate (PMMA). According to a standardized protocol, 20 PMMA cylinders (13 mm diameter, 5 mm in height) as well as 20 cubes (a = 25 mm) with intaglio U-shaped profiles were manufactured to simulate average sized alveolar ridges. Cylinders as well as cubes were divided into four test series with n = 5 each. After sandblasting with silica-modified alumina, one frontal surface of the PMMA cylinders and the intaglio surfaces of the U-shaped profiles was coated with chitosan acetate solution according to the following protocols: one layer of 2% chitosan acetate solution (test series I), one layer of 4% chitosan acetate solution (test series II), two layers of 2% chitosan acetate solution (test series III), and two layers of 4% chitosan acetate solution (test series IV). After drying and neutralization with NaOH, each cube was cut transversely and the coating thickness across the U-shaped profile assessed with a light microscope. Adhesive strength was evaluated by simulated tooth brushing and the loss of chitosan coating was evaluated qualitatively. Statistical analysis used Friedman ANOVA test for dependent samples and Kruskal-Wallis test for independent samples, post-hoc Dunn’s test (p < 0.05), and binomial test (p = 0.05). The mean chitosan coating thicknesses in the depth of the U-profiles were 71 µm (test series I), 77 µm (test series II), 121 µm (test series III), and 517 µm (test series VI). The thickness continuously decreased with rising angulation of the U-profile side walls. In test series I, the chitosan coating thickness significantly dropped above a 30° angulation of the U-profile side walls. In test series II to IV, the chitosan thickness drop was not statistically significant at angulations of 30° and 60°, but was at 90° angulation of the U-profile side walls. Adhesion strength was rated fair to good and did not differ significantly among the four test series. The coating technique described revealed chitosan layers with overall good adhesion strength but differing thicknesses. Coatings with one or two layers of 4% chitosan acetate solution allowed a relatively uniform chitosan thickness and thus might be usable in oral medicine.

Baker´s yeast (Saccharomyces cerevisiae) were magnetically modified by three different methods, namely, surface modification by magnetic fluid, entrapment of cells into alginate and covalent immobilization on particles of magnetic chitosan. The ability of H2O2 decomposition was tested for all types of modification. It is apparent that the most amount of hydrogen peroxid was degraded by magnetic fluid - modified cells (84-95%), while the efficiency of cell which were modified by other methods was much lower (40-60%). Thanks to immobilization on particles of magnetic chitosan, we made completely new type of magnetic material, which was tested for adsorption of Crystal violet and Safranin O. It was founded that magnetic chitosan adsorbs no dyes, so all adsorption belongs to immobilized yeast. The maximum adsorption capacities were determined using Langmuire isotherm at 69,4 mg/g for Crystal violet and 99,0 mg/g for Safranin O.

L’objectif de cette thèse est d’élaborer des nanohybrides à base des nanotubes de titanate (TiONts) dans le but de les utiliser comme nanovecteurs d’une molécule thérapeutique : un phénol stilbénique, le 4’ hydroxy 4 (3 aminopropoxy)-trans-stilbène (HAPtS), structurellement proche du trans-resvératrol.Les TiONts sont synthétisés par traitement hydrothermal à partir du dioxyde de titane sous sa forme rutile. Deux méthodes de synthèse hydrothermale (statique et dynamique) ont été étudiées. La deuxième méthode est originale car elle utilise un réacteur conduisant à une agitation mécanique forte par balancement où le temps d’agitation par heure de traitement peut-être contrôlé. Une étude paramétrique a été menée pour évaluer l’impact de la durée de traitement, de la température et du temps d’agitation appliqué par heure sur la morphologie des structures obtenues. Il a été montré que l’agitation par balancement, appliquée durant la synthèse, a un effet accélérateur sur la cinétique de formation des TiONts en mode dynamique. Par optimisation des paramètres de synthèse, il a été possible de réduire la durée de la synthèse des TiONts à 2h seulement, au lieu de 48 h en méthode statique. Des discussions sur la structure cristalline, le mécanisme de formation des TiONts et leur transformation en nanorubans ont également été développées en se basant sur différentes techniques de caractérisations (DRX, MET, ATG, XPS, spectroscopies UV visible, IR et Raman). La morphologie spéciale des TiONts, en spirale (diamètre externe de 10 nm, diamètre interne de 4 nm avec une longueur moyenne d’environ 190 nm) et multicouches (3 à 5 couches) leur confère une surface spécifique élevée (> 200 m²/g).Différentes préfonctionnalisations des TiONts par des ligands organiques biocompatibles ont été effectuées pour améliorer la stabilité des TiONts en suspension et greffer à leur surface des groupements fonctionnels réactifs. Les ligands étudiées sont : deux catéchols, le DHCA et la L-DOPA, l’acide citrique et deux organosilanes, l’APTES et le CPTES. Les paramètres optimaux de greffage ont été déterminés et la présence de liens covalents entre ces ligands et les TiONts ont été établis, principalement par XPS et IR.Après préfonctionnalisation avec le CPTES, le greffage du phénol stilbénique (HAPtS) a été un succès. Cette molécule a été accrochée à la surface des TiONts-CPTES par une réaction de condensation entre le HAPtS et le CPTES par substitution nucléophile et a conduit à un taux de greffage d’environ 20 mg/g de TiONts.Enfin, l’une des originalités de ce travail a consisté à améliorer la biocompatibilité des TiONts, à travers la modification de leur surface par un polymère naturel, le chitosan (CT). Ce dernier a été greffé à la surface des nanotubes par deux méthodes différentes via des liaisons covalentes (greffage étape par étape mettant en œuvre de l’APTES puis du glutaraldehyde) ou via des interactions électrostatiques (adsorption). Après comparaison entre les deux approches, les premiers tests d’évaluation de la toxicité, in vitro (test de cinétique de synthèse des ARN et test du rouge neutre) et in vivo (embryons de poisson zèbre), ont été réalisés et les résultats ont confirmé la biocompatibilité des nanohybrides synthétisés avec les systèmes biologiques. Une étude de la stabilité colloïdale des TiONts-CT dans différents milieux mimant des milieux biologiques a également été menée.Mots clés : Nanotubes de titanate, synthèse hydrothermale dynamique, nanovecteurs, nanohybrides, stabilité colloïdale, fonctionnalisation, greffage, ligands organiques, catéchols, organosilanes, phénol stilbénique, chitosan, biocompatibilité. / The aim of this PhD thesis is to develop new nanohybrids based on titanate nanotubes (TiONts) in order to use them as nanocarrier of a therapeutic molecule: a stilbene phenol, 4'-hydroxy-4-(3-aminopropoxy)-trans-stilbene (HAPtS), which is a transresveratrol derivative.TiONts are synthesized by a hydrothermal treatment from a precursor of rutile titanium dioxide. Two methods of hydrothermal synthesis have been studied (the static and dynamic ones): the second approach uses an original hydrothermal device which provides a vigorous mechanical stirring during the hydrothermal process with controllable stirring time par hour. A parametric study was carried out to evaluate the effect of reaction time, temperature and stirring time during the hydrothermal treatment on the morphology of the obtained products. It has been proved that the mechanical stirring has a great accelerating effect on the kinetics of the TiONts formation during the dynamic hydrothermal synthesis. After optimization of the experimental parameters of the dynamic hydrothermal treatment, it was possible to reduce the time of TiONts synthesis to only 2 hours, instead of 48 hours obtained by the static method. Discussions about the crystal structure of TiONts, about their formation mechanism and their transformation into nanoribbons have been also developed based on different characterization techniques (XRD, TEM, TGA, XPS, UV visible, IR and Raman spectroscopies). Their special hollow morphology (10 nm in outer diameter, inner diameter of 4 nm, average length of about 190 nm) and multilayered structure (3 to 5 layers) impart them a high specific surface area (>200 m²/g). Different prefunctionalizations of TiONts by biocompatible organic ligands have been carried out to improve their colloidal stability and to graft reactive functional groups on their surface. The studied ligands are: two catechols (DHCA and L-DOPA), citric acid and two organosilanes (APTES and CPTES). Optimal grafting parameters were determined and the presence of covalent bonds between these ligands and TiONts was highlighted especially by XPS and IR. After prefunctionalization with CPTES, the stilbenic phenol (HAPtS) was successfully grafted onto TiONts-CPTES surface using a condensation reaction between HAPtS and CPTES through nucleophilic substitution. The resulting grafting rate was of about 20 mg/g of TiONts. Finally, one of the originalities of this work was the improvement of TiONts biocompatibility by surface modification with a natural polymer, chitosan (CT). The latter was grafted by two different approaches via covalent bonds (step by step grafting using APTES then glutaraldehyde as two intermediate molecules) or via electrostatic interactions (adsorption). After comparing the two elaborated nanohybrids, obtained by the two grafting approaches, the first cytotoxicity assessment tests were carried out, in vitro (RNA synthesis test and neutral red test) and in vivo (zebrafish test), and the obtained results confirmed the biocompatibility of these nanohybrids towards biological systems. A colloidal stability study of TiONts-CT in various mimicked biological media was also carried out.Keywords: Titanate nanotubes, dynamic hydrothermal synthesis, nanocarriers, nanohybrids, colloidal stability, functionalization, grafting, organic ligands, catechols, organosilanes, stilbenic phenol, chitosan, biocompatibility.

Chitosan is known for its hemostatic and antimicrobial properties and might be useful for temporary coating of removable dentures or intraoral splints to control bleeding after oral surgery or as a supportive treatment in denture stomatitis. This study investigated a new method to adhere chitosan to polymethyl methacrylate (PMMA) and polyethylene terephthalate (PET). There were 70 cylindrical specimens made from PMMA and 70 from PET (13 mm diameter, 6 mm thickness). The materials with ten specimens each were sandblasted at 2.8 or 4.0 bar with aluminum oxide 110 μm or/and aluminum oxide coated with silica. After sandblasting, all specimens were coated with a 2% or 4% acetic chitosan solution with a thickness of 1 mm. Then the specimens were dried for 120 min at 45 °C. The precipitated chitosan was neutralized with 1 mol NaOH. After neutralization, all specimens underwent abrasion tests using the tooth-brushing simulator with soft brushes (load 2N, 2 cycles/s, 32 °C, 3000 and 30,000 cycles). After each run, the specimen surfaces were analyzed for areas of remaining chitosan by digital planimetry under a light microscope. The best chitosan adhesion was found after sandblasting with aluminum oxide coated with silica (U-Test, p < 0.05) in both the PMMA and the PET groups. Hence, with relatively simple technology, a reliable bond of chitosan to PMMA and PET could be achieved.

Chitosan is known for its hemostatic and antimicrobial properties and might be useful for temporary coating of removable dentures or intraoral splints to control bleeding after oral surgery or as a supportive treatment in denture stomatitis. This study investigated a new method to adhere chitosan to polymethyl methacrylate (PMMA) and polyethylene terephthalate (PET). There were 70 cylindrical specimens made from PMMA and 70 from PET (13 mm diameter, 6 mm thickness). The materials with ten specimens each were sandblasted at 2.8 or 4.0 bar with aluminum oxide 110 μm or/and aluminum oxide coated with silica. After sandblasting, all specimens were coated with a 2% or 4% acetic chitosan solution with a thickness of 1 mm. Then the specimens were dried for 120 min at 45 °C. The precipitated chitosan was neutralized with 1 mol NaOH. After neutralization, all specimens underwent abrasion tests using the tooth-brushing simulator with soft brushes (load 2N, 2 cycles/s, 32 °C, 3000 and 30,000 cycles). After each run, the specimen surfaces were analyzed for areas of remaining chitosan by digital planimetry under a light microscope. The best chitosan adhesion was found after sandblasting with aluminum oxide coated with silica (U-Test, p < 0.05) in both the PMMA and the PET groups. Hence, with relatively simple technology, a reliable bond of chitosan to PMMA and PET could be achieved.

Chitosan is a cationic natural polymer that is widely used as a topical dressing in wound management. Temporary coatings of removable denture bases with chitosan might be useful as supportive treatment in oral medicine. The aim of this study was to analyze the thickness, uniformity, and adhesive strength of chitosan coatings on simulated denture bases made from polymethyl methacrylate (PMMA). According to a standardized protocol, 20 PMMA cylinders (13 mm diameter, 5 mm in height) as well as 20 cubes (a = 25 mm) with intaglio U-shaped profiles were manufactured to simulate average sized alveolar ridges. Cylinders as well as cubes were divided into four test series with n = 5 each. After sandblasting with silica-modified alumina, one frontal surface of the PMMA cylinders and the intaglio surfaces of the U-shaped profiles was coated with chitosan acetate solution according to the following protocols: one layer of 2% chitosan acetate solution (test series I), one layer of 4% chitosan acetate solution (test series II), two layers of 2% chitosan acetate solution (test series III), and two layers of 4% chitosan acetate solution (test series IV). After drying and neutralization with NaOH, each cube was cut transversely and the coating thickness across the U-shaped profile assessed with a light microscope. Adhesive strength was evaluated by simulated tooth brushing and the loss of chitosan coating was evaluated qualitatively. Statistical analysis used Friedman ANOVA test for dependent samples and Kruskal-Wallis test for independent samples, post-hoc Dunn’s test (p < 0.05), and binomial test (p = 0.05). The mean chitosan coating thicknesses in the depth of the U-profiles were 71 µm (test series I), 77 µm (test series II), 121 µm (test series III), and 517 µm (test series VI). The thickness continuously decreased with rising angulation of the U-profile side walls. In test series I, the chitosan coating thickness significantly dropped above a 30° angulation of the U-profile side walls. In test series II to IV, the chitosan thickness drop was not statistically significant at angulations of 30° and 60°, but was at 90° angulation of the U-profile side walls. Adhesion strength was rated fair to good and did not differ significantly among the four test series. The coating technique described revealed chitosan layers with overall good adhesion strength but differing thicknesses. Coatings with one or two layers of 4% chitosan acetate solution allowed a relatively uniform chitosan thickness and thus might be usable in oral medicine.

L'utilisation du plutonium (Pu(IV) pour des applications militaires et civiles peut engendrer des contaminations internes chez les personnes exposées. Plusieurs voies de contamination sont possibles : par ingestion, par inhalation ou par blessure. En cas d'inhalation, le plutonium se présente le plus souvent sous forme de particules d'oxyde de plutonium qui vont se localiser au sein des alvéoles pulmonaires. Par un mécanisme de phagocytose, les particules sont internalisées par les macrophages de l'épithélium pulmonaire. Actuellement, le seul agent de décorporation administré en cas de contamination au plutonium est le DTPA (l'acide diethylenetriaminepentaacetique). Il est administré en France sous forme de CaNa3-DTPA par injection intraveineuse et est efficace pour les contaminations par ingestion et par blessure. Les nanoparticules fonctionnalisées à base de polymères naturels sont un concept innovant de décorporation du Pu(IV) solubilisé dans les macrophages pulmonaires et ouvrent la voie au développement de nouvelles familles de décorporants. C'est dans ce contexte que deux stratégies ont été développées : des nanoparticules à base de N-trimethyl chitosan fonctionnalisées par le ligand DTPMP (l'acide diéthylènetriaminepentamethylene phosphonique) qui est l'analogue phosphonique du DTPA et des nanoparticules chélatantes à base de -cyclodextrines amphiphiles anioniques. Ce travail a consisté en la synthèse et la caractérisation des nano-objets puis de l'étude de leur complexation avec les actinides (Th/Pu) en utilisant la spectroscopie EXAFS. Et enfin, des tests préliminaires biologiques in vitro ont été réalisés. Les résultats obtenus, avec les nanoparticules à base de chitosan et de DTPMP montrent que les nanoparticules présentent des tailles et une stabilité compatible avec l’application visée. D’autre part, leur affinité pour les actinides (IV) (Th,Pu) est comparable à celle du chélatant de référence, le DTPA. Enfin, les tests, effectués sur deux lignées de macrophages montrent que les nanoparticules sont internalisées très rapidement et que la matrice polysaccharidique semble se dégrader, permettant le relargage du chélateur DTPMP au niveau des sites de rétention du Pu(IV). Cette thèse constitue un travail préliminaire au développement d'une nouvelle famille d’agents décorporants plus ciblés pour une contamination au plutonium par inhalation. / The use of plutonium (Pu(IV) for military and civil applications can lead to internal contamination. There are several possible routes of contamination: ingestion, inhalation or injury. In case of plutonium inhalation, the plutonium forms oxide particles that reach the pulmonary alveoli. Through a phagocytosis mechanism, the particles are internalized by the macrophages of the pulmonary epithelium and continue to exert their toxicity. Currently, the only decorporating agent administered in the event of contamination with plutonium is DTPA (diethylenetriaminepentaacetic acid). in France, it is administered as CaNa3-DTPA by intravenous injection. This standard is effective for contamination by ingestion and injury. However, it is not effective in case of contamination by inhalation. Functionalized nanoparticles based on natural polymers constitute an innovative concept for decorporating Pu(IV) solubilized in pulmonary macrophages and open the way for the development of new families of decorporants. We investigated two strategies: chitosan-based nanoparticles functionalized by the DTPMP (diethylenetriaminepentamethylene phosphonic acid) which is the phosphonic analog of DTPA and self-organized chelating β-cyclodextrin-based nanoparticles. This work was first focused on the synthesis and characterization of the nano-objects and then on the study of their complexation abilities with actinides (Th/Pu) using EXAFS spectroscopy. Finally, preliminary in vitro biological tests were carried out. Our obtained results with DTPMP and chitosan based nanoparticles showed that these aggregates exhibit size and stability compatible with the application. Furthermore, we demonstrate their affinity for the actinides(IV) (Th, Pu) is comparable to the reference DTPA. Finally, in vitro tests realized onto macrophages show that our nanoparticles are rapidly internalized through phagocytosis and that the polysaccharide matrix seems to undergo degradation which allows the DTPMP to be released and targeted right into the sequestration sites of Pu(IV). This work constitutes a first step in the development of new family of decorporating agents with a higher efficiency in case of plutonium contamination through inhalation.