A mucopolissacaridose tipo I (MPS I) é uma doença autossômica recessiva causada pela deficiência da enzima α-L-iduronidade (IDUA). Essa deficiência resulta no acúmulo de glicosaminoglicanos levando a diversas manifestações clínicas. A microencapsulação de células recombinantes que superexpressam IDUA tem sido considerada uma estratégia promissora para o tratamento de MPS I. Neste contexto, o presente estudo teve por objetivo a otimização da encapsulação de células BHK (Baby Hamster Kidney) superexpressando IDUA em microcápsulas de alginato revestidas com poli-L-lisina (PLL) utilizando-se um extrusor eletrostático. Em uma primeira etapa, um estudo de otimização das microcápsulas de alginato (MC-A) foi realizado por meio de um desenho experimental do tipo Box-Behnken (software Mini-Tab®) que permitiu avaliar simultaneamente a influência da voltagem (kV), fluxo alginato/células (mL/h) e concentração de alginato (%) sobre o tamanho das microcápsulas e a atividade de IDUA. Após, as microcápsulas foram revestidas sequencialmente com PLL e alginato (MC-APA) com o objetivo de aumentar a sua estabilidade. Nas condições experimentais empregadas, MC-A e MC-APA apresentaram-se monodispersas (span < 1,22) com um diâmetro médio inferior a 350 μm, determinado por difração a laser. O revestimento alterou a morfologia das microcápsulas (microscopia eletrônica de varredura) e a sua resistência mecânica (analisador de textura), sendo observado um aumento de cerca de 6 vezes na força necessária para compressão das mesmas. O revestimento final pelo alginato (MC-APA) parece ter sido parcial de acordo com as análises de infravermelho por transformada de Fourier com refletância atenuada. Em uma última etapa, a atividade enzimática foi avaliada em modelo murino MPS I após implante subcutâneo de MC-APA. Foi observado um aumento significativo da atividade de IDUA na pele, após 30 dias de tratamento. Nas análises histológicas foi observado um infiltrado inflamatório no local da aplicação que não impediu a liberação da enzima nas condições avaliadas. No seu conjunto, esse estudo demonstra a potencialidade das MC-APA para a liberação local de IDUA. / Mucopolysaccharidosis type I (MPS I) is an autosomal recessive disorder caused by the deficiency of α-L-iduronidase (IDUA). This deficiency results in the accumulation of glycosaminoglycans leading to various clinical manifestations. The microencapsulation of recombinant cells overexpressing IDUA has been considered as a promising strategy for the treatment of MPS I. In this context, the present study aimed to optimize the encapsulation of BHK cells overexpressing IDUA in poly-L-lysine (PLL) coated alginate microcapsules using an electrostatic extruder. In a first step, a Box-Behnken experimental design (Mini-Tab® software) was carried out for the optimization of the alginate microcapsules (MC-A), which allowed to evaluate simultaneously the influence of voltage (kV), alginate/cell flow (mL/h) and alginate concentration (%) on the size of the microcapsules and IDUA activity. Thereafter, the microcapsules were sequentially coated with PLL and alginate (MC-APA) in order to increase their stability. In the experimental conditions used, MC-A and MC-APA were monodisperse (span <1.22) with an average diameter of less than 350 μm, determined by laser diffraction. The coating modified microcapsules morphology (scanning electron microscopy) and their mechanical resistance (texture analyzer), being observed a six-fold increase in the required force for their compression. The final alginate coating (MC-APA) appears to have only partially coated the microcapsules, according to the attenuated total reflectance Fourier transform infrared spectroscopy analyses. In a final step, the enzymatic activity was evaluated in a MPS I murine model after subcutaneous implantation of MC-APA. A significant increase in IDUA activity was observed in the skin at 30 days after treatment. Histological analszes revealed an inflammatory infiltrate at the application site, which did not prevent the release of the enzyme under the evaluated conditions. Overall, this study demonstrates the potentiality of MC-APA for the local release of IDUA.

A aplicação de uma ou mais camadas de tinta sobre as superfícies metálicas é a maneira mais comum e eficaz de proteger os substratos metálicos contra o fenômeno da corrosão. No entanto, os sistemas de pintura podem vir a falhar precocemente por diferentes motivos, causando um ataque corrosivo inesperado no metal a ser protegido. Por esta razão, o processo de repintura em estruturas metálicas é realizado frequentemente para garantir a integridade da estrutura pintada e aumentar sua vida útil. Como o processo de repintura gera impactos econômicos e ambientais, sistemas de pintura capazes de sofrerem uma reparação sem a necessidade de uma intervenção humana, precisam ser desenvolvidos. O encapsulamento de agentes de reparação, com propriedades de formação de filme, em microcápsulas poliméricas é uma excelente alternativa para que os sistemas de pintura se autorreparem, aumentando os intervalos de repintura. Após o processo de encapsulamento, as microcápsulas contendo o agente de reparação são incorporadas na preparação da tinta, para que o sistema de pintura seja aplicado sobre a estrutura metálica. Este tipo de aditivação confere ao revestimento a propriedade de autorreparação, pois quando o sistema de pintura é danificado as microcápsulas são rompidas e liberam o agente de reparação no local danificado, protegendo novamente o substrato metálico. Neste trabalho foi desenvolvido um sistema autorreparador monocomponente, através do microencapsulamento de uma resina a base de éster de epóxi, pelo método de polimerização in-situ. Também foi desenvolvido um sistema autorreparador bicomponente, através do microencapsulamento de uma resina a base de epóxi, pelo método de emulsão e polimerização in-situ de ureia-formaldeído-melamina e do seu endurecedor a base de poliamida, pelo método de extração de solvente em paredes de poliestireno. Foi realizado um planejamento estatístico para estudar a emulsão precursora das microcápsulas de poli(ureia-formaldeído-melamina) contendo o sistema monocomponente, onde foram estudados: o tipo e a velocidade de agitação, a presença de cloreto de sódio na formulação, o uso de uma sonda ultrassônica após a etapa de dispersão, a concentração de tensoativo na formulação e o tensoativo utilizado. Como variáveis de resposta foram determinadas: a estabilidade visual das emulsões e o diâmetro das gotículas formadas. A melhor condição de emulsificação determinada foi utilizada para a obtenção das microcápsulas de poli(ureia-formaldeídomelamina) contendo a resina éster de epóxi e das microcápsulas de poli(ureiaformaldeído-melamina) contento a resina epóxi. Entre as condições de emulsificação estudadas, apenas a condição utilizando o tensoativo goma arábica possibilitou a obtenção das microcápsulas de poli(ureia-formaldeído-melamina) na faixa de diâmetro desejada. O método escolhido para o encapsulamento do endurecedor possibilitou a obtenção de microcápsulas de poliestireno, porém com uma baixa capacidade de armazenamento. A liberação dos agentes de reparação encapsulados foi observada pela microscopia óptica e comprovada pela técnica de espectroscopia na região do infravermelho (FTIR) e pela técnica de espectroscopia Raman. Os aditivos autorreparadores desenvolvidos (mono e bicomponente) foram adicionados separadamente em uma tinta epóxi, nas proporções mássicas em base seca de 10 e 15 %. O sistema de pintura foi aplicado em um esquema de três camadas e o aditivo de autorreparação foi incorporado na primeira e/ou segunda camada aplicada. O sistema de pintura contendo o aditivo autorreparador monocomponente apresentou um aspecto visual melhor do que o sistema de pintura contendo o aditivo autorreparador bicomponente, porém o sistema bicomponente forneceu melhores propriedades de aderência, de impermeabilidade, anticorrosivas e de autorreparação à tinta aditivada. As medidas com as técnicas eletroquímicas de espectroscopia de impedância eletroquímica (EIE) e de varredura com eletrodo vibratório (SVET) comprovaram que os dois aditivos desenvolvidos proporcionaram o efeito autorreparador aos sistemas de pintura aditivados, quando estes foram danificados mecanicamente com uma microbroca ou com um estilete. Ensaios acelerados de corrosão em câmara de névoa salina e ensaios de exposição ao intemperismo natural mostraram que os aditivos desenvolvidos promoveram uma proteção adicional ao aço carbono, quando o sistema de pintura foi danificado mecanicamente. / The application of one or more coating layers on the metallic surfaces is the most common and effective way to protect metallic substrates against corrosion. Nevertheless, the coating layer may fail early for different reasons, leading to an unexpected corrosive attack on the protected metal. For this reason, the coating repair process is performed to ensure the integrity during the service life of the coated metallic structures. Due to the fact that coating repair process generates economic and environmental impacts; there is a great need for the development of systems capable to repair themselves, without human intervention. The encapsulation of repairing agents, with film forming properties, in polymeric microcapsules is an excellent alternative to the coating self-repair, decreasing the coating repair process frequency. After the encapsulation process, the microcapsules containing the repair agent are incorporated into the paint preparation and the coating system could be applied normally to the metallic surface. This kind of additivation confers to the coating the self-healing property, because when the coating system is damaged the microcapsules suffers a rupture and release the repair agent into the damaged site, protecting the metallic substrate from corrosion. In this work, a mono-component self-healing system was developed, through the microencapsulation of an epoxy ester resin, by the in-situ polymerization method. A bi-component self-healing system was also developed, by the microencapsulation of an epoxy resin, through the emulsion and in-situ polymerization method and by the microencapsulation of a polyamide hardener, by the double emulsion and solvent extraction method. A factorial design was developed to study the precursor emulsion of the poly (urea-formaldehyde-melamine) microcapsules containing the monocomponent system, where the studied factors were: the type and speed of the agitation, the presence of sodium chloride in the formulation, the use of an ultrasonic probe after the emulsification, the surfactant type and concentration. The analyzed response variables were: the visual stability of the emulsions and the mean diameter of the formed droplets. The best obtained emulsification conditions were employed to produce the poly(urea-formaldehyde-melamine) microcapsules containing the epoxy ester resin and poly(urea-formaldehyde-melamine) microcapsules containing the epoxy resin. Among the studied emulsification conditions, only using arabic gum surfactant the poly (urea-formaldehyde-melamine) microcapsules were obtained. The selected method for the hardener encapsulation was efficient to obtain polystyrene microcapsules, but with low loading capacity. The release of the encapsulated repair agents was observed by optical microscopy and confirmed by infrared spectroscopy (FTIR) technique and Raman spectroscopy technique. The developed self-healing additives (mono and bicomponent) were added separately in an epoxy commercial coating, using the dry mass ratios 10% and 15 %. The coating system was applied in a three layer coating system and the self-healing additive was incorporated into the first and/or second layer. The coated samples containing the mono-component additive had a better visual appearance than the bi-component additive system; nevertheless the bi-component system provided better adhesion, impermeability, anti-corrosion and self-healing properties to the doped coating. The electrochemical impedance spectroscopy (EIS) and scanning vibrating electrode technique (SVET) measurements proved that the two developed additives provided self-healing properties to the doped coating systems, when they were mechanically damaged with a micro drill or a blade. Accelerated corrosion tests in the salt spray chamber and natural atmospheric corrosion tests showed that the developed additives provided an additional protection to the carbon steel, when the coating system has been mechanically damaged.

Stimulus-responsive colloidosomes which completely dissolve upon a mild pH change are developed. pH-Responsive nanoparticles that dissolve upon a mild pH increase are synthesized by a nanoprecipitation method and are used as stabilizers for a double water-in-oil-in-water Pickering emulsion. These emulsions serve as templates for the production of pH-responsive colloidosomes. Removal of the middle oil phase produces water-core colloidosomes that have a shell made of pH-responsive nanoparticles, which rapidly dissolve above pH 7. The permeability of these capsules is assessed by FRAP, whereby the diffusion of a fluorescent tracer through the capsule shell is monitored. Three methods for tuning the permeability of the pH-responsive colloidosomes were developed: ethanol consolidation, layer-by-layer assembly and the generation of PLGA-pH-responsive nanoparticle hybrid colloidosomes. The resulting colloidosomes have different responses to the pH stimulus, as well as different pre-release permeability values. Additionally, fundamental studies regarding the role of particle surface roughness on Pickering emulsification are also shown. The pH-responsive nanoparticles were used as a coating for larger silica particles, producing rough raspberry-like particles. Partial dissolution of the nanoparticle coating allows tuning of the substrate surface roughness while retaining the same surface chemistry. The results obtained show that surface roughness increases the emulsion stability of decane-water systems (to almost twice), but only up to a certain point, where extremely rough particles produced less stable emulsions presumably due to a Cassie-Baxter wetting regime. Additionally, in an octanol-water system, surface roughness was shown to affect the type of emulsion generated. These results are of exceptional importance since they are the first controlled experimental evidence regarding the role of particle surface roughness on Pickering emulsification, thus clarifying some conflicting ideas that exist regarding this issue.

Polyelectrolyte capsules fabricated by layer-by-layer (LbL) technique are introduced as a simple and efficient carrier system for spontaneous deposition of proteins and low molecular water soluble drug. The objective of the work was to investigate the applicability of polyelectrolyte capsules as vehicles for sustained or controlled delivery of drugs. Two different polymeric systems composed of weak and strong polyelectrolytes were chosen to study the loading and release behavior in order to meet the requirements of biomedical applications. In the first system, the wall permeability of weak polyelectrolyte (PAH/PMA) capsules could be readily manipulated from open to closed state by simply varying the pH. The open and closed state of the capsules could be attributed to the charge density variation of weak polyelectrolytes, which induces the capsule wall to undergo a transition from continuous to nanoporous morphology due to phase segregation. Bovine Serum Albumin (BSA) was spontaneously deposited in the hollow capsules and deposition was investigated by CLSM, SEM and AFM techniques. The driving force for spontaneous deposition was electrostatic interaction between the preloaded polystyrene sulfonate (PSS) and BSA. The deposition was uniform and concentration of BSA in the capsule interior reached a few hundred times greater than that of bulk. The amount of loading was significantly influenced by the loading pH, loading concentration and charge density of substance to be loaded at the corresponding pH. The deposition was successful up to the isoelectric point of BSA (pH = 4.8) and there was no loading observed above that, since the deposition is based on electrostatic attraction between PSS and BSA. During the release at physiological pH of 7.4, charge reversal of BSA occurred which induced electrostatic repulsion between PSS and BSA thereby triggering the movement of BSA from the interior to the bulk. Release continued up to 5 h in water and a total release of 63 % was observed which increased to 72 % when release was performed in PBS. Spontaneous deposition of low molecular weight, water soluble drug, ciprofloxacin hydrochloride was performed in the same manner and its release profile was studied. Controlling diffusion of smaller drug molecules is extremely difficult in drug delivery applications. Cross linking of capsule wall components could be used to control the release rates of smaller drug molecules. Cross linking density is dependent on the cross linking time and increases the stiffness of the capsule wall. Release of ciprofloxacin hydrochloride was possible even up to 6 h after cross linking. Antibacterial studies showed that the drug released even after 25 h has a significant effect on the bacterial pathogen E.coli. The second system included weak and strong polyelectrolytes (PAH & DS) and a novel route was employed to fabricate optically addressable capsules that could be laser activated for delivery of drugs. This approach involved a combination of LbL assembly and polyol reduction method wherein PEG was used to reduce AgNO3 to Ag nanoparticles (NPs). The capsules were prepared via LbL assembly of PAH and DS on silica template followed by synthesis of silver NPs in the layers and subsequent dissolution of the silica core. The sulfonate groups of DS present in the polyelectrolyte film act as binding sites for the adsorption of silver ions which are then reduced to silver NPs in the presence of PEG. The size of the silver NPs formed was influenced by the AgNO3 concentration used. At lower concentration, smaller particles of uniform distribution were observed which turned into larger particles of random distribution when the concentration of AgNO3 is increased. Silver NPs embedded capsules ruptured when exposed to laser and was significantly influenced by silver NPs size, their distribution, laser intensity and time of exposure. The synthesis of silver NPs increased the permeability of the capsules to higher molecular weight substances like dextran caused by the defects, discontinuities and pores created on the polymeric network due to the newly formed silver NPs. Encapsulation of FITC-dextran was performed using thermal encapsulation method by exploiting temperature induced shrinking of the capsules at elevated temperatures. During heat treatment the porous morphology transformed into smooth pore free structure which prevented the movement of dextran into the bulk and hence enrichment inside the capsules. The loaded dextran was readily released when exposed to laser and the release could be controlled from linear to burst release in order to meet practical requirements in biomedical applications.

A materials synthesis technique was recently developed to generate polymer/nanoparticles composite microcapsules in which synthetic polyamines such as polyallylamine and/or polylysine were crosslinked with multivalent anions to form polymer-salt aggregates, that then served as templates for deposition of nanoparticles (NPs) of various compositions to form micron-sized hollow spheres or "nanoparticle-assembled capsules" (NACs). This electrostatically-driven "polymer-salt aggregate" or "PSA" assembly route is attractive for encapsulation and scale-up because encapsulation and materials formation occur in water, at mild pH values, and at room temperature. NACs can potentially find wide-ranging applications in pharmaceutical, food, and consumer products. It is of crucial importance to address the physical property aspects of NACs in view of their use and applicability. While most applications may require that NACs not disassemble or deform under shear stress, some may require triggered release under specific conditions to release the encapsulated material (e.g., enzymes or drugs). Comparatively, little has been done to assess the physical properties of NACs. The behavior of NACs under varying p1-1 and ionic strength conditions were determined. The capsules were found to be structural intact in the pH range of 4-9 at an ionic strength of 10 mM. The pH range in which they were intact narrowed with increasing ionic strength; the capsules fragmented into smaller pieces at 500 mM. The NACs could be made stable at ionic strengths as high as 1M by the addition of multivalent anions to the suspending fluid. The structurally intact NACs were found to vary in compressive strength from 1 atm to > ∼25 atm, via osmotic pressure studies. The benign assembly conditions of NACs allowed for encapsulation studies of various molecules such as fluorescein, Gd[DOTP] 5- (MRI contrast agent), doxorubicin (an anticancer drug), and uracil (pharmaceutical drug with anticancer properties). X-ray irradiation was studied as a potential external trigger for cargo release. A thorough experimental analysis on diffusive release of a dye molecule (fluorescein) from NACs was carried out. Manipulation of the PSA assembly process was carried out in several studies to explore the generality of the synthesis method. Positively-charged aluminosilicate NPs were studied in place of negatively-charged silica NPs. Surprisingly, these led to solid microspheres instead of hollow microspheres. Following the diffusion-deposition model for microsphere formation, it is seems that the NPs, with positively charged alumina patches on top of a negatively charged silica surface, can fully penetrate into the polymer-salt aggregate to form the solid microspheres. The viscoelastic nature of polymer-salt aggregates was exploited to produce non-sphere-shaped NACs through the use of a high-shear flow instrument (Reynolds number of ∼21,000). A mathematical model was developed to understand the formation of elongated NACs, which indicated the shear and elongational stresses within the boundary layer zones along the flow channel walls were responsible for the observed formation of rod-like microparticles.

This work focused on the design of functional capsules made of chemically modified polysaccharides. The layer-by-layer capsules have attracted great interest due to their Indeed, as an advanced multifunctionality which can be advantageously used for pharmaceutical and biomedical applications. Polysaccharides, which are generally biocompatible and biodegradable, are very attractive materials for the construction of bio-related multilayer systems. Considering the intrinsic antibacterial properties of chitosan (CHI), this polysaccharide was selected and quaternized to prepare in physiological conditions contact-killing capsules by combination with hyaluronic acid (HA). The relationship between the antibacterial activity of the quaternized chitosan derivatives (QCHI) and that of QCHI-based capsules was investigated. Then, in order to encapsulate small hydrophobic drugs within the wall of capsules, alkylated derivatives of HA were used as the negatively charged partner of QCHI for the capsules formation. The encapsulation of the hydrophobic dye, nile red (NR), in the hydrophobic shell of capsules was determined. At last, to release the payload under mild conditions was studied by synthesizing rapidly degradable capsules composed of hydrolysable cationic dextran derivatives and HA. The degradation of the layer-by-layer assemblies, both multilayer films and microcapsules is discussed.

Un papier bioactif est obtenu par la modification d’un papier en y immobilisant une ou plusieurs biomolécules. La recherche et le développement de papiers bioactifs est en plein essor car le papier est un substrat peu dispendieux qui est déjà d’usage très répandu à travers le monde. Bien que les papiers bioactifs n’aient pas connus de succès commercial depuis la mise en marche de bandelettes mesurant le taux de glucose dans les années cinquante, de nombreux groupes de recherche travaillent à immobiliser des biomolécules sur le papier pour obtenir un papier bioactif qui est abordable et possède une bonne durée de vie. Contrairement à la glucose oxidase, l’enzyme utilisée sur ces bandelettes, la majorité des biomolécules sont très fragiles et perdent leur activité très rapidement lorsqu’immobilisées sur des papiers. Le développement de nouveaux papiers bioactifs pouvant détecter des substances d’intérêt ou même désactiver des pathogènes dépend donc de découverte de nouvelles techniques d’immobilisation des biomolécules permettant de maintenir leur activité tout en étant applicable dans la chaîne de production actuelle des papiers fins. Le but de cette thèse est de développer une technique d’immobilisation efficace et versatile, permettant de protéger l’activité de biomolécules incorporées sur des papiers. La microencapsulation a été choisie comme technique d’immobilisation car elle permet d’enfermer de grandes quantités de biomolécules à l’intérieur d’une sphère poreuse permettant leur protection. Pour cette étude, le polymère poly(éthylènediimine) a été choisi afin de générer la paroi des microcapsules. Les enzymes laccase et glucose oxidase, dont les propriétés sont bien établies, seront utilisées comme biomolécules test. Dans un premier temps, deux procédures d’encapsulation ont été développées puis étudiées. La méthode par émulsion produit des microcapsules de plus petits diamètres que la méthode par encapsulation utilisant un encapsulateur, bien que cette dernière offre une meilleure efficacité d’encapsulation. Par la suite, l’effet de la procédure d’encapsulation sur l’activité enzymatique et la stabilité thermique des enzymes a été étudié à cause de l’importance du maintien de l’activité sur le développement d’une plateforme d’immobilisation. L’effet de la nature du polymère utilisé pour la fabrication des capsules sur la conformation de l’enzyme a été étudié pour la première fois. Finalement, l’applicabilité des microcapsules de poly(éthylèneimine) dans la confection de papiers bioactifs a été démontré par le biais de trois prototypes. Un papier réagissant au glucose a été obtenu en immobilisant des microcapsules contenant l’enzyme glucose oxidase. Un papier sensible à l’enzyme neuraminidase pour la détection de la vaginose bactérienne avec une plus grande stabilité durant l’entreposage a été fait en encapsulant les réactifs colorimétriques dans des capsules de poly(éthylèneimine). L’utilisation de microcapsules pour l’immobilisation d’anticorps a également été étudiée. Les avancées au niveau de la plateforme d’immobilisation de biomolécules par microencapsulation qui ont été réalisées lors de cette thèse permettront de mieux comprendre l’effet des réactifs impliqués dans la procédure de microencapsulation sur la stabilité, l’activité et la conformation des biomolécules. Les résultats obtenus démontrent que la plateforme d’immobilisation développée peut être appliquée pour la confection de nouveaux papiers bioactifs. / Biosensing paper attracts increasing attention due to its benefits of being simple, visible, portable and useful for detecting various contaminants, pathogens and toxins. While there has been no bioactive paper commercialized since glucose paper strips developed in the fifties, many research groups are working to immobilize biomolecules on paper to achieve a bioactive paper that is affordable and has good shelf life. The goal of this research is to develop some highly useful bioactive paper that could, for example, measure blood glucose, or immediately detect and simultaneously deactivate pathogens such as neuraminidase and E.coli. Previously, bioactive paper was produced either through physically absorbing biorecognition elements or printing bio-ink onto paper substrate. Our methodology for fabrication of bioactive paper strips is compatible with existing paper making process and includes three procedures: the fabrication of microcapsules, enzyme or antibody microencapsulation, immobilization of enzymes or antibody-entrapped microcapsules into paper pulp. The first step, in fabricating of bioactive paper strips is to produce biocompatible and inexpensive microcapsules with suitable parameters. To do so, two types of microencapsulation methods were compared; the emulsion method and the vibration nozzle method accomplished with an encapsulator. The parameters for producing optimal microcapsules with both methods were studied. Factors that affect their diameter, wall thickness, shell pore size, encapsulation efficiency and membrane compositions were also discussed. By comparison, microcapsules prepared with poly(ethyleneimine) (PEI) by the emulsion method exhibit properties that were more suitable for enzyme encapsulation and paper making process, whereas the microcapsules prepared by the vibration nozzle method were too big to be immobilized within paper pulp, and had lower encapsulation efficiency, enzymatic activity and productivity. Thus the emulsion method was chosen for subsequent experiments such as enzyme and antibody microencapsulation and bacterial vaginosis (BV) paper preparation. Microcapsules made by the emulsion method were semi-permeable in that the diffusion of substrate and product molecules were allowed freely across the membranes but the encapsulated enzymes would be retained inside. Glucose oxidase from Aspergillus niger (GOx) and laccase from Trametes versicolor (TvL) microcapsules showed high encapsulation efficiency, but the encapsulation process caused a severe decrease in the specific activities of both enzymes. Results from circular dichroism (CD) studies, fluorescence properties, enzymatic activities of free enzymes and Michaelis-Menten behavior demonstrated that the Vmax decrease for GOx was due to the restriction of diffusion across microcapsule membranes with pore size less than 5 nm. The microencapsulation process improved the thermal stability of GOx but decreased that of laccase. Bioactive papers were fabricated either by incorporating microcapsules containing different enzymes or empty microcapsules soaked in substrate and enhancer solution into the paper pulp during the sheet making process. Both the GOx and the BV paper strips underwent a color change in the presence of glucose and potassium iodide, and sialidase from Clostridium perfringens respectively. Some preliminary studies on antibody sensitized microcapsules, in which antibody was either encapsulated within the PEI microcapsules or conjugated to its membranes, were also performed. Our objective was to establish an enzyme immobilization platform based on microencapsulation techniques for paper based biosensors. Even though our current studies only focused on the microencapsulation of two enzymes, TvL and GOx, as well as the bioactive paper preparation, a similar approach can be applied to other enzymes. We believe that this immobilization method can potentially be employed for bioactive paper preparation on an industrial scale.

O consumo abusivo de embalagens plásticas tem causado diversos problemas ambientais, visto que as mesmas são produzidas a partir de fontes não renováveis de energia e são resistentes à degradação. Neste contexto, o desenvolvimento de filmes biodegradáveis ativos para aplicação em alimentos é de grande importância pois, além de serem produzidos a partir fontes renováveis e mais sustentáveis, os mesmos podem interagir com o produto embalado e proporcionar benefícios extras em relação aos filmes convencionais. Este trabalho utilizou o bagaço de uva proveniente do processo de vinificação como fonte de antocianinas para o desenvolvimento de filmes biodegradáveis com propriedades antioxidantes. A microencapsulação das antocianinas, realizada com a finalidade de aumentar sua estabilidade, utilizou maltodextrina e goma arábica como agentes encapsulantes. Diferentes formulações de filmes biodegradáveis foram desenvolvidas com as microcápsulas produzidas. Goma arábica, maltodextrina e a combinação das mesmas foram eficientes no processo de microencapsulação (>90% de retenção de antocianinas). Apesar de apresentarem o mesmo teor de antocianinas - quantificadas via cromatografia líquida de alta eficiência - a atividade antioxidante das microcápsulas de goma arábica foi maior. A diferença entre a atividade antioxidante das cápsulas foi atribuída às diferentes solubilidades destas em água, onde maiores solubilidades poderiam liberar mais facilmente as antocianinas encapsuladas. O filme desenvolvido a partir de antocianinas encapsuladas com maltodextrina apresentou melhores propriedades mecânicas e ofereceu maior proteção ao óleo de girassol frente às reações de oxidação, e portanto foi utilizado na produção de sachês de azeite de oliva extra-virgem. O filme desenvolvido apresentou biodegradabilidade comprovada e propiciou maior estabilidade oxidativa ao azeite de oliva nele embalado quando comparado a um azeite embalado em polipropileno comercial. Os resultados obtidos neste trabalho comprovam a potencialidade da utilização de maltodextrina como encapsulante de antocianinas e como ingrediente na produção de filmes biodegradáveis, aplicados principalmente em produtos gordurosos. / The abuse of plastic packaging has caused various environmental problems, since they are produced from non-renewable sources of energy and are resistant to degradation. In this context, the development of active biodegradable films for application in foods is of great importance, since they are produced from renewable and sustainable sources, besides they may interact with the packaged product and provide additional benefits over conventional films. This study used the wine grape pomace as a source of anthocyanins for the development of biodegradable films with antioxidant properties. Microencapsulation of anthocyanins, which was carried out with the purpose of increasing its stability, used maltodextrin and gum arabic as wall materials. Different formulations of biodegradable films were developed with the obtained microcapsules. Gum arabic, maltodextrin and their combination were effective in the microencapsulation process (> 90% retention of anthocyanins). Despite being provided with the same anthocyanins content - quantified by highperformance liquid chromatography - the antioxidant activity of gum arabic microcapsules was greater. The difference between the antioxidant activity of the capsules was attributed to their different solubility in water, so that capsules with higher solubility could release more easily the encapsulated anthocyanins. The film containing anthocyanins encapsulated with maltodextrin showed better mechanical properties and offered greater protection to sunflower oil against oxidation reactions, and so was used in the production of extra-virgin olive oil pouches. The developed film, which was proven to be biodegradable, increased the oxidative stability of the olive oil when compared to olive oil packaged in a commercial polypropylene. The results of this study demonstrate the potential usage of maltodextrin as wall material on encapsulation of anthocyanins and as an ingredient in the production of biodegradable films, mainly applied in fatty products.

Espumas de assentos personalizados para cadeiras de rodas se adaptam a anatomia do usuário, no entanto, ao passo que melhoram o posicionamento, podem influenciar negativamente no conforto térmico por aumentar a superfície de contato. O conforto térmico pode ser melhorado com materiais de mudança de fase (PCM), que devem ser aplicados protegidos por um invólucro para impedir seu escape na fase líquida. O invólucro mais comum são as microcápsulas. Assim, o objetivo dessa pesquisa é obter, aplicar e caracterizar microcápsulas com núcleo de material de mudança de fase, mais especificamente o eicosano, em espumas de PU flexível após sua expansão e tecido que recobre o assento, ampliando o efeito termorregulador desse material, reduzindo o tempo de aplicação e desperdício das microcápsulas. Essa é uma pesquisa de natureza aplicada, com técnica de pesquisa de documentação direta através de pesquisa em laboratório, objetivo descritivo e explicativo, com procedimento técnico experimental e abordagem quantitativa. Foram obtidas microcápsulas de eicosano com a variação de diferentes parâmetros e caracterizadas através de MEV, FTIR, granulometria, TGA e DSC. As microcápsulas foram inseridas em amostras de espuma com duas técnicas diferentes (filtração e aerografia) e essas amostras foram analisadas com um termógrafo para verificação do efeito termorregulador gerado. Pode-se concluir que a aerografia proporciona melhor aproveitamento de tempo e de material, ampliando os efeitos térmicos gerados na espuma flexível de PU. Também, o efeito térmico depende não apenas do tipo de microcápsula, mas da quantidade aplicada e sua distribuição pelo material. / Wheelchair custom seats foams can be adapt to the user’s anatomy nonetheless, although it can improve positioning, it influences negatively in thermal comfort as it increases the contact surface. Thermal comfort can be improved with phase change materials (PCM) that must be applied in a casing to prevent its escape in the liquid phase. The most common casing is the microcapsules. The main objective of this research is to obtain, apply and characterize PCM microcapsules, more specifically eicosane, into flexible PU foams after expansion and fabric that recovers the seat, enlarging the thermoregulatory effect of this material, reducing application time and microcapsule waste. It is a study of applied nature, research technique of direct documentation through laboratory investigation, descriptive and explanatory objective, and experimental technical procedure generating quantifiable data. Eicosane microcapsules were obtained varying different parameters and characterizes through SEM, FTIR, granulometry, TGA and DSC. The microcapsules were inserted into foam samples with two different techniques (filtration and aerography). These samples were analyzed through a thermographer to verify its thermoregulatory effect. It can be concluded that aerography has better use of time and material, improving the overall thermal effect in PU foam. Additionally, the thermal effect depends not only in the type of microcapsule, but also in quantity applied and distribution through out the material.

A pesquisa na área de microencapsulação tem enorme potencial para proporcionar aos produtos características únicas que resultam em produtos de qualidade superior, nesse ponto de vista, incorporar a aplicação de microcápsulas em tecido se torna uma alternativa a ser utilizada pelo designer, desenvolvendo assim produtos inovadores que agregam características únicas e qualidade superior aos produtos. Portanto, este trabalho desenvolve um estudo de métodos de aplicação de microcápsulas: cerâmicas e poliméricas, com material ativo, aromático e luminescente em suportes têxteis, utilizando-se das técnicas de serigrafia e impregnação, que confiram durabilidade aliada a um bom acabamento para o emprego no design de produtos, pois estes são alguns dos desafios encontrados quando se trata de aplicar microcápsulas. Foi utilizada a técnica da documentação indireta usando a fundamentação teórica como ferramenta. Os procedimentos experimentais consistiram em aplicação de microcápsulas em suportes têxteis com diferentes métodos. Foram utilizados dois tipos de microcápsulas, de casca cerâmica e polimérica, produzidas no Laboratório de Design e Seleção de Materiais da Universidade Federal do Rio Grande do Sul, e microcápsulas industriais, para avaliar aspectos como eficiência da aplicação, acabamento e durabilidade. Os métodos de aplicação selecionados foram serigrafia e impregnação, o teste de durabilidade foi feito baseado na norma da Associação Brasileira de Normas Técnicas NBR ISO 105-C06:2010, que se propõe a testar a resistência da cor em suportes têxteis. Como resultado geral das aplicações e testes de durabilidade, pode-se concluir que os resultados mais satisfatórios, que combinam método de aplicação, microcápsulas, suporte e substâncias combinadas (vernizes e resinas) e ainda se mostraram resistentes a 30 lavagens foram: serigrafia, microcápsulas de casca cerâmica de frutas vermelhas, combinadas com verniz serigráfico à base d´água, em tecido algodão; serigrafia, microcápsulas de casca cerâmica de frutas vermelhas, combinadas com verniz solvente, tanto em tecido algodão como em poliéster; serigrafia, microcápsulas poliméricas de frutas vermelhas combinadas com verniz à base d´água impressas em tecido algodão e poliéster; serigrafia, verniz industrial fosfocrômico, essa combinação tanto em poliéster quanto em algodão, apresentou boa resposta à luz UV; impregnação em meio aquoso durante 4 h, microcápsulas de casca cerâmica de frutas vermelhas, com adição de resina em algodão; impregnação em meio aquoso durante 1 h, microcápsulas de casca polimérica de erva-doce, com a adição de resina acrílica em algodão e poliéster. / The research in the field of microencapsulation has enormous potential to provide unique characteristics to products, resulting in superior products, in that point view, incorporate the application of microcapsules in fabric becomes an alternative to be used by the designer, developing this way innovative products that add unique features and superior quality to products. Therefore, this study develop a study of methods of application of microcapsules: ceramic and polymeric with active material, aromatic and luminescent in textile supports, using the techniques of silkscreen and impregnation, conferring durability combined to with a good finish for employment in the design of products, because these are some of the challenges encountered when it comes to applying microcapsules. We used the technique of indirect documentation using the theoretical framework as a tool. The experimental procedure consisted in applying to microcapsules in textile supports with different methods. We used two types of microcapsules, ceramic and polymeric shell, produced at the Laboratório de Design e Seleção de Materiais da Universidade Federal do Rio Grande do Sul, and industrial microcapsules, to assess aspects such as application efficiency, workmanship and durability. The application methods that were selected was silkscreen and impregnation, the durability test was done based on the standard of the Associação Brasileira de Normas Técnicas NBR ISO 105-C06: 2010, which proposes to test the strength of color in textile products. As a general result of the applications and durability tests, it can be concluded that more satisfactory results, that combine method of application, microcapsules, supports and substances combined (varnishes and resins) and also was resistant to 30 washings were: silkscreen, ceramic shell microcapsules of the red fruit, combined with varnish water-based in cotton fabric; silkscreen, ceramic shell microcapsules of the red fruit, combined with varnish solvent, on cotton fabric and polyester; silkscreen, polymeric shell microcapsules of the red fruit, combined with varnish water-based printed on cotton and polyester fabric; silkscreen printing, varnish industrial fosfocrômico, this combination both polyester and cotton, had a good response to UV light; impregnation for 4 hours, ceramic shell microcapsules, with the addition of resin on cotton; and impregnation for 1 hour, polymeric shell microcapsule, with the addition of acrylic resin at polyester and cotton.