Effect of inflammatory conditions on bare and coated Ti-6Al-4V surfaces

Abstract

Event Abstract Back to Event Effect of inflammatory conditions on bare and coated Ti-6Al-4V surfaces Sarah Höhn1 and Sannakaisa Virtanen1 1 University of Erlangen-Nürnberg, Materials Science, Germany Introduction: The calcium-phosphate (Ca-P) formation during long-term immersion in biological environment play an important role for the biocompatibility of the implant. Hence, Ti-6Al-4V was coated with different nano sized structures to evaluate corrosion resistance and Ca-P formation in DMEM under physiological (pH7) and inflammatory con-ditions (pH5 + H2O2). Methods: The samples were pretreated and afterwards coated with TiO2 and incorporated hydroxylapatite nanoparticles, according to Höhn et al[1]. The influence of the coatings on Ca-P formation was investigated with XPS and SEM after immersion in DMEM at pH7 and in comparison under simulated inflammatory conditions at pH5 and in presence of H2O2. The long-term immersion tests at pH5 were performed for 14 days followed by a pH change to pH7 indicating the end of the inflammatory reactions. The effect on corrosion resistance was investigated by electrochemical impedance measurements (EIS). Results: Fig. 1. SEM images of TiO2-NP (~ 30nm; (A)) and HA incorporated TiO2 (~ 700nm (B)) samples and after three months immersion in DMEM at pH5 + H2O2 (C) and (D). Fig. 2. EIS of TiO2-NP (A) and HA incorporated TiO2 coating (B) at pH5 + H2O2 after long-term immersion tests in DMEM. Discussion and Conclusion: The SEM images (Fig. 1) showed that the formation of Ca-P is possible on the different coatings on Ti-6Al-4V in general. However for the pH5 the formation is time-delayed (Fig. 1D). EIS measurements at pH5 showed no effect of the additional Ca-P layer after 14 days immersion. Already after 28d (Fig. 2) and the end of the inflammatory conditions both coatings showed two time constants according to the barrier layer and outer porous layer and thus the Ca-P formation[2]. Compared to the measurements at pH7 the formation is also time-delayed.