Funcionalização da liga Ti-6Al-4V com filmes finos de Nb2O5 para aplicações biomédicas

Abstract

The surgical implantation of artificial biomaterials is the most widespread solution to mitigate musculoskeletal problems, and the use of these materials depends on their synergy with the organism, as well as their degradation in the body environment. Therefore, the use of biomaterials that are not toxic to the body, that present stability and tissue compatibility, that have good mechanical properties and resistance to corrosion are some of the desired requirements in the biomedical sector for permanent implants. Since the deposition of films on the surface of biomaterials is a strategy that can be applied to improve mechanical properties and corrosion resistance, as well as to improve biological responses, the objective was to study the influence of thin Nb2O5 films deposited on the alloy surface. Ti-6Al-4V in resistance to corrosive processes and in the biofunctional properties of this alloy. The results showed that DC reactive sputtering was capable of producing thin films with a thickness in the range of 300 – 450 nm, composed of niobium oxides, mostly Nb2O5. It was verified, through different electrochemical tests in Hank's solution or NaF 0.01 mol L-1, that the film improved resistance to corrosion processes for Ti-6Al-4V/Nb2O5 compared to Ti-6Al- 4V uncoated. As interface processes are dependent on the solid state characteristics of oxide films, their optical, dielectric and electrical properties were determined through capacitance measurements, photoelectrochemical tests and multi-angle ellipsometric measurements. Furthermore, for the first time it was reported that coating with Nb2O5 thin films, obtained via DC reactive sputtering, provided antibacterial activities against S. aureus, as well as better cellular response for MC3T3 osteoblasts. All these findings corroborate the hypothesis that the Nb2O5-based coating provides protection against corrosive processes, in addition to improving bioactive properties relevant to the viability, adsorption and proliferation of cells cultured on the surface of the titanium alloy Ti-6Al-4V.