Hybrid Sol-Gel silica based coatings for enhancing osseointergation: the role of silicon.

JOSEFINA BALLARRE; RAÚL PROCACCINI; SERGIO PELLICE; SILVIA CERÉ

Madrid

Conferencia; XVII International Sol-Gel Conference; 2013

International Sol-Gel Society

Among the materials used as orthopaedic devices, metals are the most used due to their excellent mechanical properties. Nevertheless they are no able to make a natural bonding with the existing bone. The protection of AISI 316L stainless steel used as permanent implant applying a hybrid sol-gel organic-inorganic silica-based coating is one way to modify the surface of metals, acting as barrier for ion migration and being this coatings potential holders for different kind of functional particles. The effects of silicon in human health and more precisely in bone growth was been reported as essential for its catalyzed effect. This work presents coatings made by the sol-gel method containing tetraethoxysilane, methyl-triethoxysilane and silica nanoparticles as precursors by dipping. The coatings are made with a two layer system: the last film is also added with 5-10%w of glass-ceramic particles. The addition of SiO2 colloidal particles to the sol is thought to give films with bigger thickness than the ones without nanoparticles and the addition of bioactive glass-ceramic particles to the external layer generates the coatings the ability to bone with the existing bone. The behaviour of the silicon content in both cases was analyzed and compared by means of in vitro (Raman, FTIR spectroscopies) and in vivo (Raman, histology images) in tibia model of Wistar rats. The Si-OH presence in the reactive surface leads to a silica-rich layer that in vitro enhances the hydroxyapatite deposition (first insight of bioactivity). Also the in vivo reaction of the Si present in the coatings without bioactive particles presented a high amount of newly formed bone, with a comparable quality as with glass-ceramic bioactive particles.