O objetivo do presente trabalho foi testar a biocompatibilidade de um enxerto floculado de resina de mamona (AUG-EX, POLIQUIL ARARAQUARA POLÍMEROS QUÍMICOS LTDA, Araraquara, SP), utilizando-se como modelo experimental o reparo da ferida de extração dental de rato. Para tanto, foram realizadas a avaliação histológica da reação dos tecidos vizinhos ao implante e a análise histométrica da cronologia do reparo ósseo no terço alveolar contíguo ao do material implantado. Imediatamente após a extração dos incisivos superiores direitos, os animais do grupo Implantado tiveram o alvéolo parcialmente preenchido com o enxerto floculado da resina de mamona, misturado em quantidade mínima de soro fisiológico. Nos períodos de 1, 2, 3 e 6 semanas após a extração dental ou extração + implante, as hemi-maxilas direitas dos ratos controles e implantados foram coletadas, fixadas em solução de formol a 10%, a seguir descalcificadas, desidratadas, diafanizadas e incluídas em parafina para obtenção de cortes longitudinais semi-seriados de 6 µm de espessura, que foram corados com hematoxilina e eosina. A fração de volume dos componentes reparacionais da ferida de extração dental (coágulo sangüíneo, tecido conjuntivo e trabéculas ósseas) foi estimada por um método de contagem diferencial de pontos, em imagens histológicas analisadas ao microscópio óptico munido de uma ocular contendo um retículo com 100 pontos eqüidistantes, nos períodos de 2 e 6 semanas após a extração dental. As comparações entre os resultados dos grupos controles e implantados foram realizadas pelos testes estatísticos não-paramétricos de Kruskal-Wallis e Mann-Whitney. O exame histológico mostrou os flocos da resina de mamona, de forma irregular e tamanho variável, localizados entre os terços médio e cervical dos alvéolos dentais; o material mostrou-se biocompatível e capaz de certo grau de osseointegração direta, dentro do período da investigação. Os flocos foram inicialmente circundados por tecido de granulação, com a presença de trabéculas osteóides formando-se em suas proximidades. Com o progresso do reparo, quantidades gradativamente maiores de tecido ósseo em maturação foram observadas entre e ao redor dos flocos da resina, no geral com a presença de um tecido conjuntivo interposto, mas em algumas regiões estabelecendo um aparente contato direto com eles. Comparando com trabalhos anteriores do nosso laboratório, no entanto, parece que o formato irregular dos flocos não se mostrou tão favorável à aderência aos tecidos reparacionais, uma vez que ao redor das superfícies côncavas foram observadas, no geral, áreas sem preenchimento tissular. A presença do material não suscitou uma resposta inflamatória persistente, em que pese a ocorrência de uma quantidade discreta de células gigantes tipo corpo estranho aderidas a sua superfície, em todos os períodos experimentais. Embora apresentando o mesmo padrão de reparo alveolar descrito para os ratos controles, a análise histométrica do terço apical do alvéolo dos ratos implantados comprovou um atraso da ordem de 13% a 20% na neoformação óssea reparacional, com áreas mais extensas da cavidade de extração preenchidas por tecido conjuntivo e/ou remanescentes do coágulo sangüíneo, em todos os períodos experimentais. / The aim of the present study was to evaluate the biocompatibility of a natural resin made from fatty acids extracted from Ricinus communis (AUG-EX, POLIQUIL ARARAQUARA POLÍMEROS QUÍMICOS LTDA, Araraquara, SP), using as experimental model the rat alveolar healing following tooth extraction. The histological analysis of tissue reaction around the resin flakes and the histometric analysis of bone repair in the alveolar third next to the implanted material were carried out. Immediately after extraction of the upper right incisors, the alveoli of the implanted group were partially filled with the resin flakes mixed in a minimal amount of saline. The animals were killed 1, 2, 3, and 6 weeks after tooth extraction or extraction + implant, the right hemi–maxilla of the control and implanted groups were removed, fixed in 10% phormol, decalcified and processed for paraffin embedding. Longitudinal semi-serial 6 mm thick sections were stained with hematoxylin and eosin. The volume fraction of the alveolar healing components (blood clot, connective tissue and bone trabeculae) were estimated by a differential point-counting method, in histological images analyzed with an optical microscope containing a grid with 100 equidistant points, 2 and 6 weeks after tooth extraction. Results of the control and implanted groups were compared by the non-parametric Kruskal–Wallis and Mann–Whitney tests. Histological analysis showed that the material was biocompatible and capable of some degree of direct osteointegration. The resin flakes, exhibiting an irregular shape and a variable size, partially filled the middle/cervical thirds of the dental alveoli. No persistent inflammation was evoked, although a discreet foreign body reaction was observed in all the experimental periods. The material was initially encircled by granulation tissue, with the presence of delicate newly formed bone trabecula in its proximity. Progressive bone formation and maturation were noted among and around the flakes, in some areas establishing an apparent direct contact with its surface. However, it seems that the irregular shape of the flakes did not favor the adherence of biological tissues, since areas with no tissular filling were in general observed around their concave surfaces. The histometric analysis, used to quantify the healing process in the apical third from control and implanted rats, showed a small but significant delay in new bone formation in the later, which showed more extensive areas of the extraction socket filled with connective tissue and/or remaining of the blood clot, in all the experimental periods.

The methodologies utilised by pharmaceutical companies for the toxicity screening of developmental drugs are currently based on outdated two-dimensional (2D) plate-based assay systems. Although such methods provide high-throughput analysis, limitations surrounding the biomimicry of the culture environment reduces the accuracy of testing, making the process cost and time inefficient. To significantly enhance the current methods, a screening platform that is both flexible in its design and is amenable toward physiologically representative engineered tissue is required. Incorporating a flow environment within the system elicits a variety of advantages over standard static cultures, pertinently the ability to couple the flow path with automated analytical systems via the use of intuitive software. Musculoskeletal pathological conditions account for £4.76 billion of NHS spending as of 2011 (Department of Health), affecting one in four of the UK adult population. Skeletal muscle, a highly metabolic and regenerative tissue, is involved in a wide variety of functional, genetic, metabolic and degenerative pathological conditions such as muscular dystrophy, diabetes, osteoarthritis, motor neuron disease and pertinently muscular weakness associated with aging populations. Skeletal muscle tissue engineering is centred on the in vitro creation of in vivo-like tissue within laboratory environments and seeks to aid the development of future therapies, by reliably elucidating the molecular mechanisms that regulate such conditions. However, the translation of such models toward systems amenable to pharmaceutical companies has to date been limited. Microphysiological perfusion bioreactors for in vitro cell culture are a rapidly developing research niche, although state of the art systems are currently limited due to the biologically non-representative 2D culture environment, lack of adaptability toward different experimental requirements and confinement to offline analytical methods. Advancements in additive manufacture (AM), commonly known as three-dimensional (3D) printing has provided a method of production that enables researchers to hold complete design freedom and facilitate customisation of required parts. The low cost, rapid prototyping nature of AM further lends itself toward the development of such technology, with design iterations quickly and easily printed, tested and re-designed where appropriate. Issues do however, currently persist regarding the biological compatibility of printed polymers and functional material properties of parts created. As such, this thesis investigated the use of AM as a rapid and functional prototyping technique to design and develop microphysiological perfusion bioreactors. Here, biocompatibility of candidate polymers derived from commercially available 3D printing processes; fused deposition modelling (FDM), stereolithography (SL), selective laser sintering (LS) and PolyJet modelling (PJM) were elucidated. Following the biological evaluation of these polymers, their suitability, and the applicability of each process in function and manufacture of perfusion bioreactors were assessed alongside the research and development process of system designs. Specifically, attention was afforded to the homeostatic environment within bio-perfusion systems. Once finalised, the biological optimisation of designs; biocompatibility and rates of proliferation in response to the perfusion environment, was undertaken. Protocols were then established for the automated perfusion of skeletal muscle cells in both monolayer and tissue engineered 3D hydrogels. This research outlined significant contributions to the scientific literature in 3D printed polymer biocompatibility, in addition to creating bio-perfusion systems that are adaptable, analytical and facilitate the in situ phenotypic development of physiologically representative skeletal muscle tissue. Polymer biocompatibility elucidated in this work will help to facilitate the wide-ranging use of AM in biological settings. However, advancements in the chemical properties of liquid resins for advanced photo-curable processes remain necessitated for AM to be considered as a primary manufacturing technique in the biological sciences. Furthermore, although systems developed in this work have provided a base technology from which to develop and build upon, significant challenges remain in the integration of tissue engineered perfusion devices within pharmaceutical settings. Although it is plausible that the technology created in its current guise would facilitate the automated generation of skeletal muscle tissue, systems require further development to aid their usability and scale. Furthermore, work is also required to optimise the biological environment prior to mass manufacture. As such, to truly influence the pharmaceutical industry, which has invested so heavily in more traditional screening technology, a system that is all-encompassing in biology, technology and automated analytics is required.

O objetivo do presente trabalho foi testar a biocompatibilidade de um enxerto floculado de resina de mamona (AUG-EX, POLIQUIL ARARAQUARA POLÍMEROS QUÍMICOS LTDA, Araraquara, SP), utilizando-se como modelo experimental o reparo da ferida de extração dental de rato. Para tanto, foram realizadas a avaliação histológica da reação dos tecidos vizinhos ao implante e a análise histométrica da cronologia do reparo ósseo no terço alveolar contíguo ao do material implantado. Imediatamente após a extração dos incisivos superiores direitos, os animais do grupo Implantado tiveram o alvéolo parcialmente preenchido com o enxerto floculado da resina de mamona, misturado em quantidade mínima de soro fisiológico. Nos períodos de 1, 2, 3 e 6 semanas após a extração dental ou extração + implante, as hemi-maxilas direitas dos ratos controles e implantados foram coletadas, fixadas em solução de formol a 10%, a seguir descalcificadas, desidratadas, diafanizadas e incluídas em parafina para obtenção de cortes longitudinais semi-seriados de 6 µm de espessura, que foram corados com hematoxilina e eosina. A fração de volume dos componentes reparacionais da ferida de extração dental (coágulo sangüíneo, tecido conjuntivo e trabéculas ósseas) foi estimada por um método de contagem diferencial de pontos, em imagens histológicas analisadas ao microscópio óptico munido de uma ocular contendo um retículo com 100 pontos eqüidistantes, nos períodos de 2 e 6 semanas após a extração dental. As comparações entre os resultados dos grupos controles e implantados foram realizadas pelos testes estatísticos não-paramétricos de Kruskal-Wallis e Mann-Whitney. O exame histológico mostrou os flocos da resina de mamona, de forma irregular e tamanho variável, localizados entre os terços médio e cervical dos alvéolos dentais; o material mostrou-se biocompatível e capaz de certo grau de osseointegração direta, dentro do período da investigação. Os flocos foram inicialmente circundados por tecido de granulação, com a presença de trabéculas osteóides formando-se em suas proximidades. Com o progresso do reparo, quantidades gradativamente maiores de tecido ósseo em maturação foram observadas entre e ao redor dos flocos da resina, no geral com a presença de um tecido conjuntivo interposto, mas em algumas regiões estabelecendo um aparente contato direto com eles. Comparando com trabalhos anteriores do nosso laboratório, no entanto, parece que o formato irregular dos flocos não se mostrou tão favorável à aderência aos tecidos reparacionais, uma vez que ao redor das superfícies côncavas foram observadas, no geral, áreas sem preenchimento tissular. A presença do material não suscitou uma resposta inflamatória persistente, em que pese a ocorrência de uma quantidade discreta de células gigantes tipo corpo estranho aderidas a sua superfície, em todos os períodos experimentais. Embora apresentando o mesmo padrão de reparo alveolar descrito para os ratos controles, a análise histométrica do terço apical do alvéolo dos ratos implantados comprovou um atraso da ordem de 13% a 20% na neoformação óssea reparacional, com áreas mais extensas da cavidade de extração preenchidas por tecido conjuntivo e/ou remanescentes do coágulo sangüíneo, em todos os períodos experimentais. / The aim of the present study was to evaluate the biocompatibility of a natural resin made from fatty acids extracted from Ricinus communis (AUG-EX, POLIQUIL ARARAQUARA POLÍMEROS QUÍMICOS LTDA, Araraquara, SP), using as experimental model the rat alveolar healing following tooth extraction. The histological analysis of tissue reaction around the resin flakes and the histometric analysis of bone repair in the alveolar third next to the implanted material were carried out. Immediately after extraction of the upper right incisors, the alveoli of the implanted group were partially filled with the resin flakes mixed in a minimal amount of saline. The animals were killed 1, 2, 3, and 6 weeks after tooth extraction or extraction + implant, the right hemi–maxilla of the control and implanted groups were removed, fixed in 10% phormol, decalcified and processed for paraffin embedding. Longitudinal semi-serial 6 mm thick sections were stained with hematoxylin and eosin. The volume fraction of the alveolar healing components (blood clot, connective tissue and bone trabeculae) were estimated by a differential point-counting method, in histological images analyzed with an optical microscope containing a grid with 100 equidistant points, 2 and 6 weeks after tooth extraction. Results of the control and implanted groups were compared by the non-parametric Kruskal–Wallis and Mann–Whitney tests. Histological analysis showed that the material was biocompatible and capable of some degree of direct osteointegration. The resin flakes, exhibiting an irregular shape and a variable size, partially filled the middle/cervical thirds of the dental alveoli. No persistent inflammation was evoked, although a discreet foreign body reaction was observed in all the experimental periods. The material was initially encircled by granulation tissue, with the presence of delicate newly formed bone trabecula in its proximity. Progressive bone formation and maturation were noted among and around the flakes, in some areas establishing an apparent direct contact with its surface. However, it seems that the irregular shape of the flakes did not favor the adherence of biological tissues, since areas with no tissular filling were in general observed around their concave surfaces. The histometric analysis, used to quantify the healing process in the apical third from control and implanted rats, showed a small but significant delay in new bone formation in the later, which showed more extensive areas of the extraction socket filled with connective tissue and/or remaining of the blood clot, in all the experimental periods.

Orientador: Luana Marotta Reis de Vasconcellos / Coorientador: Adriano Gonçalves dos Reis / Banca: Marianne Spalding / Banca: Newton Soares da Silva / Banca: Alexandre Luiz Souto Borges / Banca: Jonatas Rafael de Oliveira / Resumo: Neste estudo foram caracterizadas superfícies de titânio (Ti) obtidas após utilização de diferentes temperaturas pela técnica de implantação iônica por imersão em plasma de oxigênio (O-IIIP), bem como correlacionado o efeito deste tratamento com a osteogênese e formação de biofilmes microbianos monotípicos. As amostras foram caracterizadas por meio de análises de química de superfície, rugosidade e textura da superfície, molhabilidade e resistência à corrosão. Além disso, análises de biocompatibilidade por meio de interação e viabilidade celular, conteúdo de proteína total, atividade de fosfatase alcalina e quantificação de nódulos de mineralização foram realizadas sobre a linhagem celular MG-63 (osteoblato humano). Análise de formação de biofilmes de Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus mutans e Candida albicans sobre as superfícies também foi realizada. Os dados foram estatisticamente analisados por teste ANOVA e Tukey (p<0,05, p<0,001 e p<0,0001). Os resultados das análises de química de superfície demonstraram um aumento proporcional da quantidade de O conforme aumento da temperatura utilizada na técnica de O-IIIP, verificando ainda a presença de TiO2 nos grupos tratados a 500ºC e 600ºC. Foi observado que, em escala nanométrica, houve um aumento significativo da rugosidade e da área superficial nas amostras tratadas com O-IIIP conforme aumento da temperatura utilizada, apresentando ainda, um aumento significativo da hidrofobicidade e resistência à ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In this study, titanium surfaces were produced by the ion implantation technique, immersing samples in oxygen plasma (O-IIIP), at different temperatures. Therapeutic effects of the surface modification were evaluated for osteogenesis and formation of monotypic microbial biofilms. Roughness, texture, wettability, corrosion resistance and chemical composition of the samples were characterized. Moreover, biocompatibility of the produced materials was verified by cell interaction and viability, total protein content, alkaline phosphatase activity, and quantification of mineralization nodules assays were performed on MG-63 (human osteoblate) cells. Biofilm formation of Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus mutans and Candida albicans on surfaces was also evaluated. Data were statistically analyzed by ANOVA and Tukey test. A proportional intensification in the amount of oxygen was observed as the temperature used in the O-IIIP technique raised, also, TiO2 was observed in the groups treated at 500 ºC and 600 ºC. At nanoscale, there was a statistic increase in both roughness and surface area in samples treated with O-IIIP as a result of the increase of the temperature used. Hydrophobicity and corrosion resistance were also higher in samples treated with OIIIP. According to the performed biocompatibility analyzes, cell viability, total protein production, alkaline phosphatase activity and the formation of mineralized nodules were stimulated and increased in the group treated with O-IIIP at 600 ºC, compared to the other groups. In the assays performed with monotypic microbial biofilms, a statistic reduction of microorganisms was observed especially in the groups submitted to O-IIIP treatment at 500 ºC and 600 ºC. Therefore, we demonstrated here that O-IIIP technique was able to chemically and physically modify surfaces,... (Complete abstract click electronic access below) / Doutor

Doctor of Philosophy(PhD) / Biomedical materials are being extensively researched, and many different types such as metals, metal alloys, and polymers are being used. Currently used biomedical materials are not perfect in terms of corrosion resistance, biocompatibility, and surface properties. It is not easy to fabricate from scratch new materials that can fulfill all requirements and an alternative approach is to modify the surface properties of current materials to cater to the requirements. Plasma immersion ion implantation (PIII) is an effective and economical surface treatment technique and that can be used to enhance the surface properties of biomaterials. The unique advantage of plasma modification is that the surface properties and functionalities can be enhanced selectively while the favorable bulk attributes of the materials such as strength remain unchanged. In addition, the non-line of sight feature of PIII is appropriate for biomedical devices with complex geometries such as orthopedic implants. However, care must be exercised during the plasma treatment because low-temperature treatment is necessary for heat-sensitive materials such as polymers which typically have a low melting point and glass transition temperature. Two kinds of biomedical materials will be discussed in this thesis. One is nickel titanium (NiTi) alloy which is a promising orthopedic implant material due to its unique shape memory and superelastic properties. However, harmful ions may diffuse from the surface causing safety hazards. In this study, we investigate the properties and performance of NiTi after nitrogen and oxygen PIII in terms of the chemical composition, corrosion resistance, and biocompatibility. The XPS results show that barrier layers mainly containing TiN and TiOx are produced after nitrogen and oxygen PIII, respectively. Based on the simulated in vitro and electrochemical corrosion tests, greatly reduced ion leaching and improved corrosion resistance are accomplished by PIII. Porous NiTi is also studied because the porous structure possesses better bone ingrowth capability and compatible elastic modulus with human bones. These advantages promote better recovery in patients. However, higher risks of Ni leaching are expected due to the increased exposed surface area and rougher topography than dense and smooth finished NiTi. We successfully apply PIII to porous NiTi and in vitro tests confirm good cytocompatibility of the materials. The other type of biomedical materials studied here is ultra-high molecular weight polyethylene (UHMWPE) which is a potential material for use in immunoassay plates and biosensors. In these applications, active antibodies or enzymes attached to a surface to detect molecules of interests by means of specific interactions are required. Moreover, the retention of enzyme activity is crucial in these applications. Therefore, the aim of this study is to investigate the use of PIII to prepare UHMWPE surfaces for binding of active proteins in terms of the binding density and ‘shelf life’ of the treated surfaces. Argon and nitrogen PIII treatments are attempted to modify the surface of UHMWPE. Horseradish peroxidase (HRP) is selected to conduct the protein binding test since it is a convenient protein to assay. Experimental results show that both PIII treated surfaces significantly improve the density of active HRP bound to the surface after incubation in buffer containing HRP. Furthermore, the PIII treated surfaces are found to perform better than a commercially available protein binding surface and the shelf life of the PIII treated surfaces under ambient conditions is at least six months. In conclusion, a biocompatible barrier layer on NiTi and a protein binding surface on UHMWPE is synthesized by PIII. The surface properties such as corrosion resistance and functionality on these two different types of substrates are improved by PIII.

Typescript. Bibliography: leaves 131-167.

The aims of this study were to prepare poly (ethylcyanoacrylate) (PECA) nanoparticles on the basis of different types of microemulsions, to investigate the entrapment within and release of a bioactive from these particles and to establish a set of delivery systems with varying entrapment and release characteristics, thereby giving the formulator the opportunity of a more tailor-made approach in the development of a delivery system. Furthermore the scale up of particle preparation and the possible enhancement of the immunogenic properties of PECA particles by incorporation of the adjuvant Quil A was investigated. Methods: Four phase triangles were established and microemulsion samples, used as a template to prepare nanoparticles, were characterised by viscosity and conductivity measurements, polarising light microscopy, freeze fracture transmission electron microscopy (TEM), cryo field emission electron microscopy (cryo FESEM) and self-diffusion NMR to determine their microemulsion type (droplet, bicontinuous, solution type). PECA nanoparticles were prepared from different types of microemulsions by interfacial polymerisation. Particle size, polydispersity index (PI) and [zeta]-potential were measured by photon correlation spectroscopy and electrophoretic mobility respectively. Normal scanning electron microscopy (SEM) and cryo FESEM were used to visualise particles. Fluorescently labelled ovalbumin (FITC-OVA) was used as a model protein/antigen and entrapment within and release from nanoparticles was investigated. To scale up nanoparticle preparation an instrumental set-up with reactor, peristaltic pump and stirrer was used. A 2⁷ fractional factorial study was designed to observe possible factors or their interactions that could influence particle formation under scale up conditions. For an immunological study freeze dried formulations of PECA nanoparticles, having FITC-OVA and Quil A entrapped, were prepared, and activation and uptake of formulations by murine bone marrow derived dendritic cells (DCs) and T cells in vitro were monitored. Results: Results obtained from the measurements described above, for formulations from the four different phase triangles, indicated that microemulsions of w/o droplet, bicontinuous or solution type could be formed. It was possible to prepare PECA nanoparticles from all of the different types of microemulsions. Particles had an average size of 265 nm � 24, with an average PI of 0.18 � 0.05 and an average negative [zeta]-potential of -17 mV � -5. Particle size, PI and [zeta]-potential were not influenced by the type of microemulsion that was used as a polymerisation template. Entrapment and release were however influenced by the type of microemulsion and although entrapment of FITC-OVA was generally high for PECA particles, it was highest for particles prepared from a droplet type microemulsion. Entrapment could also be increased by increasing amounts of monomer. The rate of release was dependent on the amount of monomer used for polymerisation and the type of microemulsion used for particle preparation, with nanoparticles prepared from a w/o droplet type microemulsion showing the slowest release. Furthermore it was shown that particle preparation could be scaled-up with the instrumental set-up used in this study, but conditions need to be refined as the average particle size and polydispersity index were considerably larger (441 nm � 101, 0.68 � 0.14) when compared to particles prepared by the beaker-pipette method (see above). The adjuvant Quil A could efficiently be entrapped into PECA nanoparticles together with FITC-OVA. Incubation of DCs and T cells with the various formulations did, however, not result in increased uptake or activation. Conclusions: PECA nanoparticles with high entrapment efficiency of antigen and adjuvant can be prepared from different types of microemulsions. Particles show different rates of entrapment and release depending on the type of microemulsion used as a polymerisation template, possibly because two different types of nanoparticles form. Nanocapsules are believed to form on the basis of droplet type microemulsions and nanospheres form on the basis of bicontinuous and solution type microemulsions. Freeze dried formulations of PECA nanoparticles, containing Quil A and FITC-OVA, were not able to induce an immune response, which might be due to charge repulsion effects between the negatively charged PECA nanoparticles and the negatively charged surface of dendritic cells. Moreover, no adjuvant effect of Quil A was apparent, perhaps caused by total encapsulation of the compound into the particle matrix with no active groups extending out displaying adjuvanticity.

El objetivo principal de esta tesis ha sido el desarrollo de nuevos poliuretanos a partir de ácidos grasos como fuentes renovables, utilizando química “click” en la síntesis de los dioles y polioles correspondientes. La primera parte del trabajo describe la preparación de los monómeros “vía” acoplamiento tiol-eno ó tiol-ino, su caracterización y las propiedades de los poliuretanos sintetizados. Como los polímeros a partir de ácidos grasos provienen de macromoléculas biológicas y pueden ser potencialmente biocompatibles, la segunda parte del trabajo está dirigida a incrementar la biocompatibilidad de los poliuretanos a través de diversas estrategias de funcionalización con moléculas bioactivas, para su implementación en ingeniería de tejidos. Tres metodologías fueron investigadas: mezclas con gelatina; inmovilización covalente de colágeno sobre la superficie mediante plasma; e inmovilización iónica de sulfato de condroitina sobre la superficie mediante aminólisis. / The main objective of this thesis has been the development of new polyurethanes from renewable sources such as fatty acids, using "click" chemistry in the synthesis of the corresponding diols and polyols. The first part of this study describes the preparation of monomers "via" thiol-ene or thiol-yne coupling, characterization and properties of the synthesized polyurethanes. As the polymers from fatty acids derived from biological macromolecules and can be potentially biocompatible, the second part of this work is focused on the enhancement of polyurethanes biocompatibility through bioactive molecules functionalization strategies, for tissue engineering purposes. Three approaches have been investigated: blends of polyurethanes and gelatin; covalent surface modification of polyurethanes with collagen by plasma treatment; and ionic surface modification of polyurethanes with chondroitin sulfate by aminolysis treatment.

Thesis (M. Phil.)--University of Hong Kong, 2010. / Includes bibliographical references (leaves 116-130). Also available online.

Thesis (M. Phil.)--University of Hong Kong, 2010. / Includes bibliographical references (leaves 116-130). Also available in print.