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

CERÉ, SILVIA; BALESTRIERE, MELINA; MERLO, JULIETA LETICIA; BALLARRE, JOSEFINA

Monitored from Belgrade, Serbia due to COVID-19 pandemic

Congreso; 71th. Anual meeting of the International Society of Electrochemistry; 2020

International Society of Electrochemistry

In developing countries, stainlesssteel is still a material that is employed for the fabrication of permanentimplants as fixation plates and hip prosthesis. The aim of these implants is toreplace the lost mechanical function of the damaged hard tissue, and togenerate a bond with the existing bone to avoid movement and loosening. Themain disadvantage of stainless steel is regarding its corrosion behaviour andthe release of potentially toxic ions to the surrounding tissues when implanted[1],[2]. Besides, stainlesssteel does not present bioactivity and it does not exhibit any antibacterialbehaviour [3].  In thiscontext a challenge to improve the material appears: to modify the surfaceimplant to improve the osseointegration process when cement-less implants areused to improve bone fixation and stabilization together with the searching forantibacterial properties of the material to be implanted.  Since corrosion is a surface phenomenon, theimplant surface and its engineering, play a key role in the performance inservice of the implant. In this work,stainless steel plane samples were coated with a hybrid organic inorganicsilica based layer made by sol-gel method. The system consists in a two- layercoating of tetraethylorthosilicate, (TEOS) and methyltrimethoxysilane (MTMS). The first layer is a protective one, and the second isa 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 surfaceas well as bioactivity. Surface behavior and corrosion resistance of thegenerated systems were analyzed by roughness measurements, adhesion of thecoatings, FTIR, SEM and corrosion tests in simulate body fluid solution at 37°C. Also antibacterial behavior was evaluated.All coatings with theaddition of silicate and borosilicate glasses showed bioactivity after 14 daysof 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 goodelectrochemical response, with high breaking potential and lower currentdensity than the bare material. Although the dissolution rate of the BS-Cu andBS particles was high, the  coatingspresented excellent corrosion resistance.