CONICET | Buscador de Institutos y Recursos Humanos

An increasing number of investigations in the bone tissue engineering field demonstrate that bioactive silicate glasses (BG) may improve vascularisation and bone regeneration. The chemical composition of BG can be varied to tailor their rate of dissolution in the biological environment. The substitution of strontium (Sr) by calcium generates a local controlled release of Sr-ion to the media. Strontium is known to reduce bone resorption and stimulate bone formation. The protection of AISI 316L stainless steel used as permanent implant applying a hybrid organic-inorganic sol-gel coating is one way to modify the surface of metals, acting as a barrier for ion migration and being this coatings a potential holder for different kind of functional particles. This work presents coatings made by the sol-gel method containing tetraethoxysilane (TEOS), methyl-triethoxysilane (MTES) and 10% in mol of silica nanoparticles as precursors by dipping, and functionalized either with BG or Sr-substituted BG particles onto surgical grade stainless steel. The coatings were analyzed by terms of surface reaction and integrity in Simulated Body Fluid (SBF) solution with diffractive, spectroscopic, microscopic and electrochemical methods. The presence of apatite-related compounds was confirmed by Raman with characteristic phosphate peaks at 960 and 1050-70 cm-1. Electrochemical impedance spectroscopy and potentiodynamic curves were used to evaluate the protectiveness of the coatings in function of immersion time in SBF. The applied coating system provided an excellent protection of the bare metal to the aggressive fluids, even after 30 days of immersion were the dissolution and re-deposition of the BG and Sr-BG particles is taking place.