Prospecção e síntese de poli(ácido láctico) para desenvolvimento de suportes na engenharia tecidual / Prospection and synthesis of poly (lactic acid) for scaffold development in tissue engineering

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

26/10/2011

RESUMO

The advances in modern medicine, dentistry and engineering, combined with the increase of life expectancy, have allowed the development of techniques for biomanufacturing and biomaterials that create a better life quality. These techniques should enable the mimicking of living structures, both in form and function, making it possible to replace defective or missing tissues. In this context the study and application of bioresorbable polyesters as scaffolds in tissue engineering has shown a very promising area of research. Poly(lactic acid), PLA, stands out among the commonly used bioresorbable polyesters due to its excellent biocompatibility and mechanical properties. PLA is a thermoplastic, high strength and is degraded in the body by simple hydrolysis of the ester at a rate that can be controlled. The most common way to obtain high molecular mass PLA is by ring-opening polymerization of the lactic acid cyclic dymer, lactide, and currently the widely used catalyst for biomedical purposes is Stannous Octoate or Sn(Oct)2. However, in order to enable the synthesis of a metal-free material, the use of enzymes as catalysts has attracted the interest of researchers. In addition to being considered non-toxic, the enzyme enables the polymerization under mild conditions with regard to pressure, temperature and pH. The aim of this work was to make a prospective study on the existing techniques for the synthesis of PLA and synthesize it from a chemical route, using Sn(Oct)2 as catalyst, and from a enzymatic route using the biocatalyst Lipase B for future development of biodevices to be used in tissue engineering. The polymer molecular mass was obtained by GPC and its chemical structure was confirmed by FTIR. Thermal properties were studied by DSC and TGA. PLA obtained from the chemical route reached molecular mass equivalent to 8353g.mol-1 after 7 hours of reaction at 160°C with 0,1% Sn(Oct)2. For the enzymatic route, it was found that the polycondensation was more effective compared to the technique of ring opening of lactide and polymer with a molecular mass of 1719g.mol-1 was obtained after 77 hours reaction time at 70°C with 0,5% of Lipase B. Comparing manufacturing costs, chemical route were more attractive at first, but it was proven that with Lipase reuse enzymatic polymerization can be economically viable

ASSUNTO(S)

síntese poli(ácido láctico) biopolímeros engenharia tecidual synthesis poly (lactic acid) biopolymers tissue engineering

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