Effects of thermal oxidation of gamma titanium aluminide on human osteoblast adhesion

Abstract

The corrosion resistance of gamma titanium aluminide (gamma-TiAl), a potential implant material, is increased in vitro by thermal oxidation. Although the biocompatibility of autoclaved gamma-TiAl was previously demonstrated, the osteoblast response to thermally oxidized gamma-TiAl has not been addressed to date. Thus, the adhesion of human osteoblasts to oxidized gamma-TiAl surfaces was examined in vitro. Cell adhesion on thermally oxidized Ti6Al-4V was evaluated for comparison. hFOB 1.19 cells were seeded on autoclaved (GTi, TiV), thermally oxidized at 500ºC (GTi5, TiV5), and at 800ºC (GTi8, TiV8) gamma-TiAl and Ti-6Al4V disks, respectively. A hexosaminidase assay, Scanning Electron Microscopy (SEM) and immunofluorescent labeling of β1 integrin and vinculin were used to evaluate cell adhesion on the different surfaces. Hexosaminidase assay showed no differences in cell attachment on all surfaces 1 day postseeding, but fewer cells were attached on TiV8 compared to those attached on the other surfaces, 7 and 14 days postseeding. Expression of β1 integrin and vinculin in cells cultured for 7 days on all the surfaces, except on TiV8, was demonstrated by immunofluorescent labeling. SEM images showed that cells adhered on all but TiV8 surfaces, 14 days postseeding. Taken together, the results indicate that hFOB 1.19 cells were able to attach and proliferate on autoclaved and both thermally oxidized gamma-TiAl surfaces in a similar manner, suggesting its biocompatibility. On the contrary, TiV8 surfaces exhibit cytotoxic effects on hFOB 1.19 cells in a time dependent manner.