Corrosion resistance and bioactivity of silica-based coatings with borosilicate/copper glasses on stainless steel implants

CERE, SILVIA; BALESTRIERE, M.A.; MERLO JULIETA; BALLARRE, JOSEFINA

evento on line por COVID

Congreso; 71st Annual ISE Meeting Belgrade Online; 2020

international society of electrochesmistry

In developing countries, stainless steel is still a material that is employed for the fabrication of permanent implants as fixation plates and hip prosthesis. The aim of these implants is to replace the lost mechanical function of the damaged hard tissue, and to generate a bond with the existing bone to avoid movement and loosening. The main disadvantage of stainless steel is regarding its corrosion behaviour and the release of potentially toxic ions to the surrounding tissues when implanted [1], [2]. Besides, stainless steel does not present bioactivity and it does not exhibit any antibacterial behaviour [3]. In this context a challenge to improve the material appears: to modify the surface implant to improve the osseointegration process when cement-less implants are used to improve bone fixation and stabilization together with the searching for antibacterial properties of the material to be implanted. Since corrosion is a surface phenomenon, the implant surface and its engineering, play a key role in the performance in service of the implant.In this work, stainless steel plane samples were coated with a hybrid organic inorganic silica based layer made by sol-gel method. The system consists in a two- layer coating of tetraethylorthosilicate, (TEOS) and methyl trimethoxysilane (MTMS). The first layer is a protective one, and the second is a functionalized one: this is achieved by the incorporation of silicate (13-93) and borosilicate (BS) glasses as a bioactive phase. Also a copper-borosilicate (BS-Cu) glass was used as an attempt of giving antibacterial properties to the surface as well as bioactivity. Surface behavior and corrosion resistance of the generated systems were analyzed by roughness measurements, adhesion of the coatings, FTIR, SEM and corrosion tests in simulate body fluid solution at 37 °C. Also antibacterial behavior was evaluated.All coatings with the addition of silicate and borosilicate glasses showed bioactivity after 14 days of immersion in SBF. Also 13-93 glass presented the faster rate of dissolution, generating pits or holes in the coatings surface.The coatings presented a good electrochemical response, with high breaking potential and lower current density than the bare material. Although the dissolution rate of the BS-Cu and BS particles was high, the coatings presented excellent corrosion resistance.