As embalagens ativas têm ganhado destaque no mercado mundial, pois possibilitam a interação do alimento com o material da embalagem, permitindo a incorporação de compostos ativos. Dentre os compostos ativos, o extrato etanólico de cúrcuma (EEC) tem chamado atenção, devido suas propriedades antioxidante, antimicrobiana, dentre outras. Assim, os objetivos deste trabalho foram desenvolvimento, caracterização e aplicação de filmes à base de gelatina aditivados com EEC. Os filmes foram produzidos pela técnica de casting (2 g de gelatina/100 g de solução filmogênica (SF), 30 g de sorbitol/100 g de gelatina) e o EEC foi incorporado na SF, nas concentrações de 0, 5, 50, 100, 150 e 200 g EEC/100 g de gelatina. Os filmes foram caracterizados em relação às propriedades mecânicas, conteúdo de água, matéria solúvel, permeabilidade ao vapor de água, parâmetros de cor, opacidade, brilho, microestrutura, espectroscopia de infravermelho com transformada de Fourier (FTIR), barreira UV/Vis, transparência, teor de curcumina, atividade antioxidante e atividade antimicrobiana. O filme com os melhores resultados para as propriedades mecânicas, barreira UV/Vis e atividade antioxidante foi utilizado para embalar noz macadâmia e, as propriedades da noz foram avaliadas em função do tempo de estocagem. A incorporação do EEC melhorou as propriedades mecânicas dos filmes, a tensão de ruptura aumentou de 27,7 MPa (filme controle) para 35,1 MPa (filme com 200 g de EEC/100 g de gelatina) e a elongação na ruptura aumentou de 22,3 % (filme controle) para 36,5 % (filme com 200 g de EEC/100 g de gelatina). O conteúdo de água não foi influenciado pela adição do EEC, porém a matéria solúvel reduziu em relação ao filme controle. A permeabilidade ao vapor de água também reduziu em média 24,1 % para os filmes aditivados. Os parâmetros de cor, opacidade e brilho foram afetados pela incorporação do EEC. As análises de microestrutura indicaram alterações na rugosidade da superfície e um aumento na rugosidade da estrutura interna, em função do aumento da concentração de EEC nos filmes. A análise de FTIR mostrou deslocame ntos dos picos associados às amidas A, I e II para os filmes aditivados. Os filmes com EEC apresentaram reduzida transmitância na região UV/Vis e aumento da transparência. O teor de curcumina aumentou linearmente (y=0,6115x+6,6629, R2=0,9817) com o aumento da concentração do extrato. A capacidade antioxidante aumentou em função do aumento da concentração do EEC e a atividade antimicrobiana (Staphylococcus aureus) foi verificada para concentrações acima de 5 g de EEC/100 g de gelatina. Assim, o filme com concentração de EEC de 200 g de EEC/100 g de gelatina foi utilizado para embalar noz macadâmia. Em relação ao conteúdo de água da noz macadâmia foram observadas diferenças significativas em função do tipo de filme utilizado (com e sem ad ição de EEC) nos primeiros 30 dias de estocagem. Entretanto, para a atividade de água não foram observadas diferenças. Após 60 dias a dureza da noz macadâmia embalada com o filme aditivado foi superior e as substâncias reativas (ácido tiobarbitúrico) fora m inferiores. Pode-se concluir que é possível a utilização desse sistema como embalagem ativa para a noz macadâmia. / Active packaging has been receiving growing attention in the world market because it allows interaction between food and packaging material, thus enabling the incorporation of active compounds. Among active compounds, curcuma ethanol extract (CEE) has been highlighted mainly because its antioxidant and antimicrobial properties. The objectives of this study were the development, characterization and application of gelatin-based films added with CEE. The films were produced by casting technique (2 g gelatin/100 g filmogenic solution (FS), 30 g sorbitol/100 g gelatin) and CEE was added to FS at 6 concentrations (0, 5, 50, 100, 150 and 200 g CEE/100 g gelatin). The films were characterized regarding mechanical properties, water content, soluble matter, water vapor permeability, color parameters, opacity, gloss, microstructure, Fourier transform infrared spectroscopy (FTIR), light transmission, transparency, curcumin content, antioxidant activity, and antimicrobial activity. The film with the best results concerning mechanical properties, light transmission and antioxidant activity was selected to package macadamia nut, whose properties were evaluated during the storage time. The addition of CEE improved mechanical properties of the films: tensile strength increased fro m 27.7 MPa (control film) to 35.1 MPa (film with 200 g CEE/100 g gelatin) and the elongation at break increased from 22.3 % (control film) to 36.5 % (film with 200 g CEE/100 g gelatin). Water content was not affected by the addition of CEE, however soluble matter reduced compared to control film. The water vapor permeability for added films also reduced on average 24.1 %. Color parameters, opacity and gloss were affected by the incorporation of CEE. Microstructure analysis indicated changes in surface roughness and increase in roughness regarding the internal structure due to the growing concentration of CEE in the films. FTIR analysis showed peaks displacements associated to amides A, I and II for the added films. Films added CEE showed reduced transmittance for the UV/Vis region and increased transparency. The curcumin content increased linearly (y=0.6115x+6.6629, R2=0.9817) with increasing extract concentration. The antioxidant capacity increased was improved with the increase of extract concentration and antimicrobial activity (Staphylococcus aureus) was verified at concentrations above 5g CEE/100g gelatin. Thus, the film with CEE concentration of 200 g CEE/100 g gelatin was used for macadamia nut packaging. Regarding water content in the macadamia nut, significant differences in the first 30 day of storage were found according to the film (with or without CEE). However, no significant difference concerning water activity was found. After 60 days of storage nuts packaged with added film had their hardness increased and lower reactive substances (thiobarbituric acid). It can be concluded that the utilization of this system as active packaging for macadamia nut is possible.

Malgré un large éventail d'applications de la gélatine et en dépit de son utilisation très ancienne, sa composition et sa structure ne sont pas encore entièrement connues et comprises. La gélatine est obtenue à partir de tissus animaux (peaux ou os) et est le résultat de l'hydrolyse partielle du collagène. La production de gélatine la plus abondante est celle de peau de porc qui représentait 46% de la production totale en 2007. Parmi les nombreuses applications, la gélatine de peau de porc est utilisée comme ingrédient principal des gélules dures pour l'industrie pharmaceutique. Une propriété importante de ces gélules est qu'elles fondent dans l'eau à une température au-dessus de 30° C et libèrent facilement les médicaments qu’elles contiennent dans le tube digestif. Les gélules dures doivent répondre à des spécifications de dissolution strictes tout au long de leur durée de conservation d'environ cinq ans. Ainsi, un test de dissolution dans l'eau est appliqué à la gélatine artificiellement vieillie dans des conditions de température et d'humidité élevées. Bien qu'avant le vieillissement le taux de dissolution de la gélatine corresponde toujours aux besoins de l'industrie pharmaceutique, une grande variabilité du taux de dissolution est observée après vieillissement. De plus, cette variabilité de dissolution dépend de l'origine de production de la gélatine. Dans ce contexte, un premier objectif était de comprendre les mécanismes sous-jacents impliqués dans la variabilité de la qualité de dissolution de la gélatine de peau de porc. Un deuxième objectif était d'identifier d'éventuels "marqueurs" de la dissolution de la gélatine afin de prédire son comportement au cours du vieillissement. Trois différents sites de production ont été choisis: deux en Europe et un aux USA. Au cours du vieillissement, la formation de cross-links a été mise en évidence et parmi ces cross-links, la dityrosine a été identifiée comme marqueur du vieillissement. En outre, les taux d'amines et d'aldéhydes ont diminué. Etant donné que ces deux fonctions sont connues pour réagir ensemble; ce résultat suggère qu'elles pourraient former d'autres cross-links au cours du vieillissement. Le processus d'oxydation dans la gélatine a été clairement démontré. De plus, la quantité de triple-hélices et leur stabilité au chauffage ont diminué alors que la quantité de conformation aléatoire et, probablement, de boucles-β augmente. Les résultats ont mis en évidence que l'origine de production affecte la composition chimique de la gélatine. Par exemple, la quantité de cross-links formés, comme la dityrosine, dans les gélatines fraîches et vieillies, différait selon l'origine de production. Nous avons également pu souligner que l'environnement physico-chimique de l'arginine permettait de distinguer l'origine de production de la gélatine. En ce qui concerne la dissolution de la gélatine, celles présentant des taux de dissolution non conformes avaient plus de phase amorphe après vieillissement que les gélatines conformes. L'implication des lipides dans la diminution de la dissolution de la gélatine a également été mise en évidence. La haute teneur en fer était également liée à la diminution de la dissolution mais seulement dans un site de production, ce qui suggère que la variabilité de dissolution a probablement des causes multifactorielles et dépendantes de l'origine de production.Avec le dichroïsme circulaire, nous avons pu discriminer les gélatines conformes des non-conformes avant même le vieillissement de ces gélatines. Cependant, l'interprétation des résultats reste très difficile en raison du manque d'information dans la littérature. Un tel résultat est important pour prédire le comportement de la gélatine avant le vieillissement. De manière générale, nos résultats ont mis en évidence qu’il serait pertinent de contrôler et de réduire le niveau d'oxydation et la teneur en lipides de la gélatine pour diminuer sa variabilité de dissolution. (...) / Despite a wide range of applications of gelatin and despite its very former use, gelatin composition and structure remains not fully known and understood. It is derived from animal tissue (skins or bones) and is the result of partial hydrolysis of collagen. The most abundant gelatin production, which is the focus of the present work, is pig skin gelatin which represented 46% of total production in 2007. Among numerous applications, gelatin is used as the main ingredient of the hard capsules for the pharmaceutical industry. An important property of hard capsules is that they melt in water at a temperature above 30°C and easily release drugs in the human digestive tract. Hard capsules have to meet strict dissolution specifications all along a shelf life of about five years. Thus, a dissolution test in water is applied to the gelatin constituting the hard capsules, after being artificially aged under high temperature and humidity conditions. While before aging the dissolution rate of gelatin always fit with requirement of pharmaceutical industry, a high variability in dissolution rate is observed after aging. Moreover, this dissolution variability was shown depending on the gelatin origin of production. In this context, a first objective of this work was to understand the underlying mechanisms involved in the variability of the dissolution quality of pig skin gelatin. A second objective was to identify possible “markers” of gelatin dissolution in order to predict the behaviour of gelatin through aging. Three different sites of production were chosen: two in Europe and one in USA. Cross-links formation was evidenced during aging, and among them, dityrosine was expressly identified as a marker of aging. In addition the levels of amines and aldehydes were decreased. Given that these two functions could react together; this result suggests that they could form other cross-links. Oxidation process in gelatin was clearly demonstrated. Furthermore, the quantity of triple-helices and their stability to heating decreased while the quantity of random coil and, probably, β-turns conformations increased. The results highlighted that origin of production impacts the chemical composition of gelatin. For instance, the extent of cross-link formation, such as dityrosine, in both fresh and aged gelatins, differed according to the origin of production. It was also pointed out that the physico-chemical environment of arginine allowed the distinction of production origin of gelatin. Regarding the gelatin dissolution, those showing non-compliant dissolution rates exhibited higher content of amorphous phase after aging than compliant ones. The implication of lipids in the decrease of gelatin dissolution rate was also evidenced. The decrease in dissolution was linked to the iron content only in one production site supporting the fact that dissolution variability has probably multifactorial causes, depending on the origin of production. The compliant and non-compliant dissolution rates were discriminate even before aging of gelatins by circular dichroism. However, the results interpretation remains quite difficult due to lack of literature information.Such a result is of importance in a view of predicting the behavior of gelatin before aging. To display a general overview, our results highlighted that, in order to reduce variability in the dissolution of gelatin, controlling and reducing the oxidation level and the lipid content will be relevant levers. To study the structural conformation thoroughgoing small angles neutrons would be an interesting tool. To complete the characterization of gelatin composition, quantifying and profiling lipids and sugars would be useful to better understand the gelatin oxidative instability.

Peripheral vascular diseases such as peripheral artery disease (PAD) and critical limb ischemia (CLI) are growing at an ever-increasing rate in the Western world due to an aging population and the incidence of type II diabetes. A growing economic burden continues because these diseases are common indicators of future heart attack or stroke. Common therapies are generally limited to pharmacologic agents or endovascular therapies which have had mixed results still ending in necrosis or limb loss. Therapeutic angiogenic strategies have become welcome options for patients suffering from PAD due to the restoration of blood flow in the extremities. Capillary sprouting and a return to normoxic tissue states are also demonstrated by the use of angiogenic cytokines in conjunction with bone marrow cell populations. To this point, it has been determined that spatial and temporal controlled release of growth factors from vehicles provides a greater therapeutic and angiogenic effect than growth factors delivered intramuscularly, intravenously, or intraarterialy due to rapid metabolization of the cytokine, and non-targeted release. Furthermore, bone marrow cells have been implicated to enhance angiogenesis in numerous ischemic diseases due to their ability to secrete angiogenic cytokines and their numerous cell fractions present which are implicated to promote mature vessel formation. Use of angiogenic peptides, in conjunction with bone marrow cells, has been hypothesized in EPC mobilization from the periphery and marrow tissues to facilitate neovessel formation. For this purpose, controlled release of angiogenic peptides basic fibroblast growth factor (FGF-2) and granulocyte-colony stimulating factor (G-CSF) was performed using tunable ionic gelatin hydrogels or fibrin scaffolds with ionic albumin microspheres. The proliferation of endothelial cell culture was determined to have an enhanced effect based on altering concentrations of growth factors and method of release: co-delivery versus sequential. Scaffolds with these angiogenic peptides were implanted in young balb/c mice that underwent unilateral hindlimb ischemia by ligation and excision of the femoral artery. Endpoints for hindlimb reperfusion and angiogenesis were determined by Laser Doppler Perfusion Imaging and immunohistochemical staining for capillaries (CD-31) and smooth muscle cells (alpha-SMA). In addition to controlled release of angiogenic peptides, further studies combined the use of a fibrin co-delivery scaffold with FGF-2 and G-CSF with bone marrow stem cell transplantation to enhance vessel formation following CLI. Endpoints also included lipophilic vascular painting to evaluate the extent of angiogenesis and arteriogenesis in an ischemic hindlimb. Tissue engineering strategies utilizing bone marrow cells and angiogenic peptides demonstrate improved hindlimb blood flow compared to BM cells or cytokines alone, as well as enhanced angiogenesis based on immunohistochemical staining and vessel densities.

This work presents the development of entropy-elastic gelatin based networks in the form of films or scaffolds. The materials have good prospects for biomedical applications, especially in the context of bone regeneration. Entropy-elastic gelatin based hydrogel films with varying crosslinking densities were prepared with tailored mechanical properties. Gelatin was covalently crosslinked above its sol gel transition, which suppressed the gelatin chain helicity. Hexamethylene diisocyanate (HDI) or ethyl ester lysine diisocyanate (LDI) were applied as chemical crosslinkers, and the reaction was conducted either in dimethyl sulfoxide (DMSO) or water. Amorphous films were prepared as measured by Wide Angle X-ray Scattering (WAXS), with tailorable degrees of swelling (Q: 300-800 vol. %) and wet state Young’s modulus (E: 70 740 kPa). Model reactions showed that the crosslinking reaction resulted in a combination of direct crosslinks (3-13 mol.-%), grafting (5-40 mol.-%), and blending of oligoureas (16-67 mol.-%). The knowledge gained with this bulk material was transferred to the integrated process of foaming and crosslinking to obtain porous 3-D gelatin-based scaffolds. For this purpose, a gelatin solution was foamed in the presence of a surfactant, Saponin, and the resulting foam was fixed by chemical crosslinking with a diisocyanate. The amorphous crosslinked scaffolds were synthesized with varied gelatin and HDI concentrations, and analyzed in the dry state by micro computed tomography (µCT, porosity: 65±11–73±14 vol.-%), and scanning electron microscopy (SEM, pore size: 117±28–166±32 µm). Subsequently, the work focused on the characterization of the gelatin scaffolds in conditions relevant to biomedical applications. Scaffolds showed high water uptake (H: 630-1680 wt.-%) with minimal changes in outer dimension. Since a decreased scaffold pore size (115±47–130±49 µm) was revealed using confocal laser scanning microscopy (CLSM) upon wetting, the form stability could be explained. Shape recoverability was observed after removal of stress when compressing wet scaffolds, while dry scaffolds maintained the compressed shape. This was explained by a reduction of the glass transition temperature upon equilibration with water (dynamic mechanical analysis at varied temperature (DMTA)). The composition dependent compression moduli (Ec: 10 50 kPa) were comparable to the bulk micromechanical Young’s moduli, which were measured by atomic force microscopy (AFM). The hydrolytic degradation profile could be adjusted, and a controlled decrease of mechanical properties was observed. Partially-degraded scaffolds displayed an increase of pore size. This was likely due to the pore wall disintegration during degradation, which caused the pores to merge. The scaffold cytotoxicity and immunologic responses were analyzed. The porous scaffolds enabled proliferation of human dermal fibroblasts within the implants (up to 90 µm depth). Furthermore, indirect eluate tests were carried out with L929 cells to quantify the material cytotoxic response. Here, the effect of the sterilization method (Ethylene oxide sterilization), crosslinker, and surfactant were analyzed. Fully cytocompatible scaffolds were obtained by using LDI as crosslinker and PEO40 PPO20-PEO40 as surfactant. These investigations were accompanied by a study of the endotoxin material contamination. The formation of medical-grade materials was successfully obtained (<0.5 EU/mL) by using low-endotoxin gelatin and performing all synthetic steps in a laminar flow hood. / Diese Arbeit beschreibt die Entwicklung Entropie-elastischer Gelatine-basierter Netzwerke als Filme und Scaffolds. Mögliche Anwendungen für die entwickelten Materialien liegen im biomedizinischen Bereich, insbesondere der Knochenregeneration. Im ersten Schritt der Arbeit wurden Entropie-elastische, Gelatine-basierte Hydrogel-Filme entwickelt, deren mechanische Eigenschaften durch die Veränderung der Quervernetzungsdichte eingestellt werden konnten. Dazu wurde Gelatine in Lösung oberhalb der Gel-Sol-Übergangstemperatur kovalent quervernetzt, wodurch die Ausbildung helikaler Konformationen unterdrückt wurde. Als Quervernetzer wurden Hexamethylendiisocyanat (HDI) oder Lysindiisocyanat ethylester (LDI) verwendet, und die Reaktionen wurden in Dimethylsulfoxid (DMSO) oder Wasser durchgeführt. Weitwinkel Röntgenstreuungs Spektroskopie (WAXS) zeigte, dass die Netzwerke amorph waren. Der Quellungsgrad (Q: 300-800 vol. %) und der Elastizitätsmodul (E: 70 740 kPa) konnten dabei durch die systematische Veränderung der Quervernetzungsdichte eingestellt werden. Die Analyse der Quervernetzungsreaktion durch Modellreaktionen zeigte, dass die Stabilisierung der Hydrogele sowohl auf kovalente Quervernetzungen (3-13 mol.-%) als auch auf Grafting von (5-40 mol.-%) und Verblendung mit Oligoharnstoffen (16-67 mol.-%) zurückgeführt werden kann. Die Erkenntnisse aus dem Umgang mit dem Bulk-Material wurden dann auf einen integrierten Prozess der Verschäumung und chemischen Quervernetzung transferiert, so dass poröse, dreidimensionale Scaffolds erhalten wurden. Dafür wurde eine wässrige Gelatinelösung in Gegenwart eines Tensids, Saponin, verschäumt, und durch chemische Quervernetzung mit einem Diisocyanat zu einem Scaffold fixiert. Die Scaffolds hergestellt mit unterschiedlichen Mengen HDI und Gelatine, wurden im trockenen Zustand mittels Mikro Computertomographie (µCT, Porosität: 65±11–73±14 vol.-%) und Rasterelektronenmikroskopie (SEM, Porengröße: 117±28–166±32) charakterisiert. Anschließend wurden die Scaffolds unter Bedingungen charakterisiert, die für biomedizinische Anwendungen relevant sind. Die Scaffolds nahmen große Mengen Wasser auf (H: 630 1680 wt.-%) bei nur minimalen Änderungen der äußeren Dimensionen. Konfokale Laser Scanning Mikroskopie zeigte, dass die Wasseraufnahme zu einer verminderten Porengröße führte (115±47–130±49 µm), wodurch die Formstabilität erklärbar ist. Eine Formrückstellung der Scaffolds wurde beobachtet, wenn Scaffolds im nassen Zustand komprimiert wurden und dann entlastet wurden, während trockene Proben in der komprimierten Formen blieben (kalte Deformation). Dieses Entropie-elastische Verhalten der nassen Scaffolds konnte durch die Verminderung der Glasübergangstemperatur des Netzwerks nach Wasseraufnahme erklärt werden (DMTA). Die zusammensetzungsabhängigen Kompressionsmoduli (Ec: 10 50 kPa) waren mit den mikromechanischen Young’s moduli vergleichbar, die mittels Rasterkraftmikroskopie (AFM) gemessen wurden. Das hydrolytische Degradationsprofil konnte variiert werden, und während des Abbaus kam es nur zu kontrolliert-graduellen Änderungen der mechanischen Eigenschaften. Während der Degradation konnte ein Anstieg der mittleren Porengröße beobachtet werden, was durch das Verschmelzen von Poren durch den Abbau der Wände erklärt werden kann. Die Endotoxinbelastung und die Zytotoxizität der Scaffolds wurden untersucht. Humane Haut-Fibroblasten wuchsen auf und innerhalb der Scaffolds (bis zu einer Tiefe von 90 µm). Indirekte Eluat-Tests mit L929 Mausfibroblasten wurden genutzt, um die Zytotoxizität der Materialien, insbesondere den Einfluss des Quervernetzertyps und des Tensids, zu bestimmen. Vollständig biokompatible Materialien wurden erzielt, wenn LDI als Quervernetzer und PEO40 PPO20-PEO40 als Tensid verwendet wurden. Durch den Einsatz von Gelatine mit geringem Endotoxin-Gehalt, und die Synthese in einer Sterilarbeitsblank konnten Materialien für medizinische Anwendungen (Endotoxin-Gehalt < 0.5 EU/mL) hergestellt werden.

The derivation of embryonic stem cells (ESCs) has created an invaluable resource for scientific study and discovery. Further improvement in differentiation protocols is necessary to generate the large number of cells needed for clinical relevance. The goal of this work was to develop a method to incorporate biomaterial microparticles (MPs) within stem cell aggregates and to evaluate their use for local control of the cellular microenvironment for directed differentiation. The effects of unloaded MPs on ESC differentiation were first determined by controlled incorporation of poly(lactic-co-glycolic acid) (PLGA), agarose and gelatin MPs. Embryoid body (EB) formation, cell viability, and gross morphology were not affected by the presence of the MPs. Further analysis of gene expression and patterns of phenotypic marker expression revealed alterations in the differentiation profile in response to material incorporation. The ability of MPs to direct ESC differentiation was investigated by incorporation of growth factor loaded MPs within EBs. MPs were loaded with bone morphogenetic protein-4 (BMP-4). BMP-4 loaded MPs incorporated within EBs induced mesoderm gene expression while inhibiting expression of an ectoderm marker compared to untreated EBs. Finally, magnetic MPs (magMPs) were incorporated within EBs to induce magnetic sensitivity. The responsiveness of EBs to applied magnetic fields was controlled by the number of magMPs incorporated within the aggregates. Magnetic guidance was then used to control the precise location of single EBs or populations of EBs for bioreactor culture and for construction of heterogeneous cell constructs. Overall, the results indicated that PSC differentiation within spheroids is sensitive to various types of biomaterials. Incorporation of MPs within EBs can be used to direct ESC differentiation by control of the cellular environment from microscale interactions, by delivery of soluble factors, to macroscale interactions, by control of EB position in static and suspension cultures.

Lymph node metastasis is a critical prognostic factor for lung cancer. Effective therapy to control lymphatic metastasis may improve survival. The work described in this thesis focuses on the development of a microparticulate lymphatic targeting system, which can be applied as an adjuvant therapy in the control of lymphatic metastasis in lung cancer. The study shows that intrapleural administered colloidal particulates are predominantly taken up by regional lymphatic tissue in rat models including healthy rats, rats bearing orthotopic lung tumours and rats following pneumonectomy. The effect of particle size on lymphatic particle distribution was examined by intrapleural administration of 111In-aminopolystyrene beads. Approximately 2 µm is a suitable size for intrapleural lymphatic targeting. Biodegradable polylactide-co-glycolide (PLGA) microparticles containing the anticancer agent paclitaxel (PTX) were subsequently formulated in the desired size by spray drying. PLGA-PTX microspheres were incorporated into a biodegradable and biocompatible gelatin sponge matrix to form an implantable lymphatic targeted drug delivery system. The system was characterized in vitro and its lymphatic targeting ability was examined in vivo. Fluorescence labeled microspheres embedded within the sponge were selectively taken up by regional lymphatics as the sponge matrix disintegrated following intrapleural implantation. A pharmacokinetic study showed that the total PTX exposure in lymphatic tissue was dramatically higher than that achieved through intravenous administration. The peak plasma drug concentration, which governs systemic toxicity, was significantly reduced. The low but persistent detection of plasma PTX indicates that PTX was control released from the system after intrapleural implantation. In a therapeutic efficacy study performed in the H460 orthotopic lung cancer model, gelatin sponges containing PLGA-PTX microspheres were placed in the pleural cavity as an adjuvant treatment after surgical resection of the primary lung tumour. Trans-lymphatic chemotherapy resulted in a significantly lower incidence of lymphatic tumour recurrence (20%) compared to no treatment and placebo control animals (100%). PLGA-PTX microspheres were seen in regional lymphatic tissue over 4 weeks after the sponge placement. It is concluded that the trans-lymphatic targeting drug delivery system described in this thesis may improve the control of lymphatic metastasis in lung cancer.

Lymph node metastasis is a critical prognostic factor for lung cancer. Effective therapy to control lymphatic metastasis may improve survival. The work described in this thesis focuses on the development of a microparticulate lymphatic targeting system, which can be applied as an adjuvant therapy in the control of lymphatic metastasis in lung cancer. The study shows that intrapleural administered colloidal particulates are predominantly taken up by regional lymphatic tissue in rat models including healthy rats, rats bearing orthotopic lung tumours and rats following pneumonectomy. The effect of particle size on lymphatic particle distribution was examined by intrapleural administration of 111In-aminopolystyrene beads. Approximately 2 µm is a suitable size for intrapleural lymphatic targeting. Biodegradable polylactide-co-glycolide (PLGA) microparticles containing the anticancer agent paclitaxel (PTX) were subsequently formulated in the desired size by spray drying. PLGA-PTX microspheres were incorporated into a biodegradable and biocompatible gelatin sponge matrix to form an implantable lymphatic targeted drug delivery system. The system was characterized in vitro and its lymphatic targeting ability was examined in vivo. Fluorescence labeled microspheres embedded within the sponge were selectively taken up by regional lymphatics as the sponge matrix disintegrated following intrapleural implantation. A pharmacokinetic study showed that the total PTX exposure in lymphatic tissue was dramatically higher than that achieved through intravenous administration. The peak plasma drug concentration, which governs systemic toxicity, was significantly reduced. The low but persistent detection of plasma PTX indicates that PTX was control released from the system after intrapleural implantation. In a therapeutic efficacy study performed in the H460 orthotopic lung cancer model, gelatin sponges containing PLGA-PTX microspheres were placed in the pleural cavity as an adjuvant treatment after surgical resection of the primary lung tumour. Trans-lymphatic chemotherapy resulted in a significantly lower incidence of lymphatic tumour recurrence (20%) compared to no treatment and placebo control animals (100%). PLGA-PTX microspheres were seen in regional lymphatic tissue over 4 weeks after the sponge placement. It is concluded that the trans-lymphatic targeting drug delivery system described in this thesis may improve the control of lymphatic metastasis in lung cancer.

In tissue engineering applications, use of biodegradable and biocompatible materials are essential. As the tissue regenerate itself on the material surface, the material degrades with enzymatic or hydrolytic reactions. After a certain time, natural tissue takes the place of the artificial support. Poly(&epsilon / -caprolactone) (PCL) is one of the preferable polymers used in the restoration of the bone defects due to its desirable mechanical properties and biocompatibility. Addition of inorganic calcium phosphate particles in PCL structures can improve the mechanical properties as well as osteoconductivity / and presence of an antibiotic can prevent infection that may occur at the defect site. In this study, three forms of biodegradable hard tissue supports which are bone fillers, bone regenerative membranes and 3D scaffolds were designed and prepared. As biodegradable bone fillers, composite microspheres containing gelatin and &beta / -tricalcium phosphate (&beta / -TCP) were prepared and characterized. Synthesized &beta / -TCP particles were coated with gelatin at different weight ratios and the effects of &beta / -TCP/Gelatin ratio on the morphology of the microspheres were evaluated. Also, a model antibiotic, gentamicin, was loaded to these microspheres and release behaviours of the drug and its antibacterial effect on E.Coli was determined. The selected composition of these microspherical bone fillers were used as additives in the preparation of bone regenerative membranes and scaffolds. For this purpose, microspheres were added into PCL solution and processed by either solvent casting or freeze-drying in order to prepare bone regenerative membranes or scaffolds, respectively. For every material, the ratio of constituents (microsphere and PCL) was altered in order to obtain optimum properties in the resulted hard tissue support structure. The effects of the ratio of the microspheres to PCL in terms of morphological, mechanical and degradation properties of composite films, as well as in vitro antibiotic release and antibacterial activities against E.Coli and S.Aureus were investigated. For scaffolds, the effects of the ratio of the microspheres to PCL on the morphological, mechanical, pore size distribution, degradation properties and in vitro antibiotic release were examined.

Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Nesta dissertação, foram estudadas a preparação e a caracterização debionanocompósitos à base de gelatina e magnetita. Sacarose foi empregada comoagente de reticulação e gelatina tipo A e gelatina tipo B foram comparadas nautilização para a preparação das microesferas por meio de emulsão água-em-óleo.As microesferas foram caracterizadas por VSM, DSC, TGA, FTIR, testes deinchamento, espectroscopia de absorção atômica, microscopia ótica e microscopiaeletrônica de varredura. Um planejamento de experimentos variando-se aconcentração de gelatina e de sacarose, a temperatura e a velocidade de agitaçãofoi realizado a fim de encontrar quais parâmetros influenciam o diâmetro dasmicroesferas. A concentração de gelatina e velocidade de agitação foram osparâmetros diretamente associados com os tamanhos de partículas. A distribuiçãode tamanho das partículas revelou que o diâmetro das microesferas variou de 5 a 60micrômetros, com predominância na faixa de 11 a 30 micrômetros. A extensão dareticulação foi aumentada com o aumento do tempo de aquecimento na etapa depreparação das microesferas. Todos os bionanocompósitos apresentaramsuperparamagnetismo. Os resultados mostraram que não há diferença significativa entre a utilização de gelatina do tipo A e gelatina do tipo B. Além disso, o estudo de reticulação degelatina revelou que, ao contrário do que diz a literatura, a sacarose não é umagente de reticulação para as cadeias proteicas, pois não foram encontradasevidências de uma reação química entre a sacarose e gelatina / The preparation and characterization of microbeads based on gelatin and magnetite are reported. Sucrose was employed as crosslinking agent and type A gelatin and type B gelatin were compared for preparation of microspheres by water-in-oil emulsion. The microbeads were characterized by VSM, DSC, FTIR, swelling ratio, atomic absorption spectroscopy and optical and scanning electronic microscopy. The influence of gelatin and sucrose concentration, temperature and stirring speed on the microbeads characteristics was studied. The gelatin concentration and stirring speed were the parameters directly associated with the particle sizes. The particle size distribution revealed that the diameter of the microspheres ranged from 5 to 60 micrometers, with predominance in the range from 11 to 30 micrometers. The extent of cross linking increased as a function of preparation heating time periods. The microbeads presented superparamagnetism. The results show that have no significant difference between the utilization of type A gelatin and type B gelatin. In addition, the gelatin crosslinking study revealed that sucrose is not a crosslinking agent because there was no evidence of chemical reaction between sucrose and gelatin

Made available in DSpace on 2014-12-17T14:06:55Z (GMT). No. of bitstreams: 1 AnaPP.pdf: 5176837 bytes, checksum: 9d8890c4a2dd055dfe7d581f34a7f4e8 (MD5) Previous issue date: 2011-01-07 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Nickel-based catalysts supported on alumina have been widely used in various reactions to obtain synthesis gas or hydrogen. Usually, higher conversion levels are obtained by these catalysts, however, the deactivation by coke formation and sintering of metal particles are still problems to be solved. Several approaches have been employed in order to minimize these problems, among which stands out in recent years the use of additives such as oxides of alkali metals and rare earths. Similarly, the use of methodologies for the synthesis faster, easier, applicable on an industrial scale and to allow control of the microstructural characteristics of these catalysts, can together provide the solution to this problem. In this work, oxides with spinel type structure AB2O4, where A represents divalent cation and B represents trivalent cations are an important class of ceramic materials investigated worldwide in different fields of applications. The nickel cobaltite (NiCo2O4) was oxides of spinel type which has attracted considerable interest due to its applicability in several areas, such as chemical sensors, flat panel displays, optical limiters, electrode materials, pigments, electrocatalysis, electronic ceramics, among others. The catalyst precursor NiCo2O4 was prepared by a new chemical synthesis route using gelatine as directing agent. The polymer resin obtained was calcined at 350?C. The samples were calcined at different temperatures (550, 750 and 950?C) and characterized by X ray diffraction, measurements of specific surface area, temperature programmed reduction and scanning electron microscopy. The materials heat treated at 550 and 750?C were tested in the partial oxidation of methane. The set of techniques revealed, for solid preparations, the presence of the phase of spinel-type structure with the NiCo2O4 NixCo1-xO solid solution. This solid solution was identified by Rietveld refinement at all temperatures of heat treatment. The catalyst precursors calcined at 550 and 750?C showed conversion levels around 25 and 75%, respectively. The reason H2/CO was around 2 to the precursor treated at 750?C, proposed reason for the reaction of partial oxidation of methane, one can conclude that this material can be shown to produce synthesis gas suitable for use in the synthesis Fischer-Tropsch process / Catalisadores a base de n?quel suportados em alumina, t?m sido amplamente empregados nas diversas rea??es para obten??o de g?s de s?ntese ou hidrog?nio. Normalmente, altos n?veis de convers?o s?o obtidos por estes catalisadores, entretanto, a desativa??o por forma??o de coque e sinteriza??o das part?culas met?licas s?o ainda problemas a serem solucionados. Diversas abordagens t?m sido empregadas com a finalidade de minimizar estes problemas, dentre as quais tem se destacado nos ?ltimos anos a utiliza??o de aditivos como ?xidos de metais alcalinos e metais terras raras. Paralelamente, o uso de metodologias de s?nteses mais r?pidas, f?ceis, aplic?veis em escala industrial e que permitam o controle das caracter?sticas microestruturais destes catalisadores, pode em conjunto, prover a solu??o para este problema. Neste trabalho, ?xidos com estrutura tipo espin?lio AB2O4, onde A representa c?tions divalentes e B representa c?tions trivalentes, s?o uma classe importante de materiais cer?micos mundialmente investigados em diferentes campos de aplica??es. As cobaltitas de n?quel (NiCo2O4) s?o ?xidos do tipo espin?lio que tem atra?do consider?vel interesse devido a sua aplicabilidade em diversas ?reas, como em sensores qu?micos, monitores de tela plana, limitadores ?pticos, materiais para eletrodos, pigmentos, eletrocat?lise, cer?micas eletr?nicas, entre outras. O precursor catal?tico NiCo2O4 foi preparado por uma nova rota de s?ntese qu?mica usando a gelatina como agente direcionador. A resina polim?rica obtida foi tratada termicamente a 350?C. As amostras foram calcinadas em diferentes temperaturas 550, 750 e 950?C e caracterizadas por difra??o de raios X, medidas de ?rea superficial espec?fica, redu??o a temperatura programada e microscopia eletr?nica de varredura. Os materiais tratados termicamente a 550 e 750?C foram testados na oxida??o parcial do metano. O conjunto de t?cnicas revelaram, nos s?lidos preparados, a presen?a da fase de estrutura espin?lio do tipo NiCo2O4 juntamente com a solu??o s?lida NixCo1-xO. Esta solu??o s?lida foi identificada atrav?s do refinamento Rietveld em todas as temperaturas de tratamento t?rmico. Os precursores catal?ticos calcinados a 550 e 750?C apresentaram n?veis de convers?o em torno de 25 e 75%, respectivamente. A raz?o H2/CO foi em torno de 2 para o precursor tratado a 750?C, raz?o proposta pela rea??o de oxida??o parcial do metano, pode-se concluir que este material pode ser indicado para produzir g?s de s?ntese adequado para ser utilizado na s?ntese de Fischer-Tropsch