Human Osteoblast Response to Porous Titanium with Biomimetic Coating

Objectives: The experiment aimed to evaluate in vitro osteogenesis comparing cell behavior after contact with titanium samples of different porosities with/without biomimetic treatment. Methods: Porous Ti discs were fabricated by the powder metallurgy process and divided into seven groups: a)Control: well's plate (C), b)dense titanium sample (Ti), c)sample with 33% of porosity (33%), d)samples with 41% of porosity (41%), e)dense Ti-sample with biomimetic treatment (TiB), f)sample with 33% of porosity with biomimetic treatment (30%B) and g)samples with 41% of porosity with biomimetic treatment (41%B). The biomimetic coating was done with alkali (NaOH) treatment, followed by heat treatment at 200°C and submersion of samples in modified simulated body fluid, changed every 48h, for 14 days. Osteoblastic cells were isolated, by sequential enzymatic digestion of explants, from healthy human alveolar bone. It was done in accordance to Ethical Principles, in triplicate and cells grew until subconfluence with supplemented a-Minimum Essential Medium. Then, cells were subcultured in 24-well culture plates on each group sample at a cell density of 2x10⁴ cells/sample, for periods of up to 14 days. Adhesion test was done after 24 hours with count in Newbauer chamber. The cell viability was determinated by [(bromide 3-4.5-dimethylthiazol-2-yl)-2,5-difeniltetrazoliol] colorimetric assay. Total protein content was obtained by modified method of Lowry and alkaline phosphatase activity was accessed using a commercial kit. Results:  ANOVA and Tukey tests showed that adherent cells percentage and alkaline phosphatase activity were similar in titanium samples apart of porosity and presence of biomimetic coating (Graphic). However, phosphate hydroxide deposition in samples with biomimetic treatment reduced the total protein content and the viability of the tested cells. Conclusion: Analyzing the behavior of cells based on the results it was concluded that biomimetic treatment impaired the biocompatibility of titanium.

Graphic – In vitro effects of porosity and biomimetic treatment in titanium samples