Improving the osteointegration and bone-implant interface by incorporation of bioactive particles in sol-gel coatings of stainless steel implants

J. BALLARRE; INDERCHAND MANJUBALA; WIDO H. SCHREINER; JUAN C. ORELLANO; PETER FRATZL; SILVIA CERÉ

Acta Biomaterialia

Elsevier

Año: 2010 vol. 9 p. 1601 - 1609

1742-7061

In this study, we report a hybrid TEOS-MTES sol-gel made coatings as a potential solution to improve the corrosion protection of AISI 316L stainless steel which is used as permanent bone implant material. These coatings act as a barrier for ion migration thus enhancing corrosion resistance and increasing the bioactivity of the implant surface. The addition of SiO2 colloidal particles to the TEOS-MTES sol (10 or 30 mol. %) leads to thicker films and also act as a film reinforcement. Also, the addition of bioactive glass ceramic (GC) particles is considered responsible for enhancing osseointegration. In vitro assays for bioactivity in simulated body fluid (SBF) showed the presence of crystalline hydroxyapatite (HA) crystals on the surface of the 10 mol % SiO2 coated stainless steel samples after 30 days of immersion. The HA crystal lattice parameters are slightly different from compared to stoichiometric HA. In vivo implantation experiments were carried out in a rat model to observe the osteointegration of the coated implants. The coatings promote the development of newly-formed bone in the periphery of the implant, both in remodellation zone and in the marrow zone. The quality of the newly-formed bone was assessed for mechanical and structural integrity by nanoindentation and small angle X-ray scattering (SAXS) experiments. The different amount of colloidal silica present in the coating slightly affects the material quality of the newly formed bone but the nanoindentation results reveal that the lower amount of silica in the coating leads to mechanical properties similar to cortical bone.