Caracterização física do carbono pirolítico utilizado na produção de próteses valvulares cardiácas mecânicas

Abstract

In this work we study the mechanical end microestrutural proprieties of pyrolytic carbon (PyC) used in the fabrication of heart valves. This material has low corrosion and oxidation rates, high biocompatibility and chemical inertia. The mechanical strength was characterized by four points bending tests. Statistical analyses were performed using the Weibull theory to establish quality criteria for this biomaterial. High quality PyC is a result of a conjunction of several mechanical proprieties such as: high Weibull modulus, fracture stress and toughness. X-Ray Diffraction and Raman Spectroscopy show a nanostructured material with crystallite size around 20 to 50 nm. Scanning Electron Microscopy reveals differences in morphologies of fractured surface without relationship with mechanical proprieties. In this work, we also develop new process of surface modification to improve hemocompatibility by reducing the interaction between blood- substrate. Platelet aggregation and in-vivo tests was done with great improvements of the hemocompatibility of these modified surfaces.