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|Title:||Obtenção, caracterização e estudo da adsorção de proteinas na blenda biorreabsorvivel poli(Beta-hidroxibutirato) (PHB)/poli(L-acido lactico) (PLLA)|
|Advisor:||Santana, Cesar Costapinto, 1948-|
|Abstract:||Resumo: A utilização de materiais poliméricos biodegradáveis na área médica foi um importante avanço biotecnológico, esses materiais podem ser utilizados como implantes temporários substituindo uma função particular do organismo por um período prédeterminado e degradar "in vivo" evitando cirurgia para a retirada do implante. O material a ser escolhido depende das necessidades da aplicação e da biocompatibilidade do material com o organismo vivo. O presente trabalho teve por objetivo estudar blendas de poli(Lácido láctico) (PLLA) / polihidroxibutirato (PHB) para aplicação na área médica. As blendas foram preparadas por dois métodos: evaporação do solvente e por fusão, obtendose amostras nas formas de filmes e pinos, respectivamente. Os filmes foram caracterizados por: análise termogravimétrica (TGA), calorimetria diferencial de varredura modulada (l|
Abstract: The use of polymeric biodegradable materials in medicine is an important progress in biotechnology. These materials can be used like temporary implants as substitute a specific function of the organism for a pre-determined period, and its degradation "in vivo", so that there is no need for subsequent surgery to remove the implant The choice of the material will depend on the needs demanded for a certain application and the biocompatibility material/organism The aim of this work was to study poly(ß-hydroxybuyrate) (PHB) I poly(L-lactic acid) (PLLA) blends for medical area application. The blends were prepared from two different methods: casting and melting, obtaining samples in the forms of films and pins, respectively. The films were characterized by thermogravimetric analysis (TGA), modulated dynamical scanning calorimetry (MDSC), dynamical mechanical analysis (DMA), scanning electron microscopy (SEM), wide-angle X-ray scattering (W AXS), small-angle X-ray scattering (SAXS), and the pins, besides the techniques mentioned above, were characterized by flexural mechanical test. The "in vitro" study of the PHBIPLLA blends was accomplished and their hydrolytic degradation was evaluated. Experiments of human protein adsorption (albumin - HSA, imunoglobulin G HIgG, fibrinogen - HFg) onto biomaterials surfaces (PHB, PLLA PHBIPLLA) were made. These experiments used the Fourier transform intrared spectroscopy (FT-IR) coupled with attenuated total reflectance (ATR) in a continuous flow system, and simulated the physiological conditions in real time to study the biomaterials biocompatibility. The biocompatibility study was complemented using capillary electrophoresis analysis. The results showed that the PHB/PLLA are immiscible, with phase separation; however, with some interaction among the phases. Pins showed dense fracture surfaces, like films of pure PHB and PLLA, while the blends of films showed porous fracture surface. The PHBIPLLA blends revealed better thermal and mechanical properties than pure PHB. It is suggested that the PLLA presence promoted these results. In the degradation study we could observe that PLLA is more susceptible to biological environrnent than PHB and blends, because it presents a faster degradation in a comparison for films and pins. The results also showed that the PHB got to maintain its mechanical properties for more time than PLLA, despite of PHB has mechanical properties inferior than PLLA. During the degradation the samples disclosed tendency to crystallize, probably increasing the crystal lamellar thickness. The biocompatibility study showed density adsorption protein values, HSA and HIgG, onto biomaterials surfaces very similar to those reported in the literature. lt is suggested that the PHBIPLLA blends have potentiality to be used as bioreabsorbables polymers in the medical area
|Subject:||Fourier, Espectroscopia de infravermelho por transformada de|
|Appears in Collections:||FEQ - Dissertação e Tese|
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