Biological evaluation of highly ordered TiO2 nanotubes produced on Ti6Al4V alloys manufactured via electron beam powder bed fusion (EB-PBF)

This experimental work evaluates the biological activity of highly ordered TiO2 nanotubes produced on Ti6Al4V samples manufactured via electron beam powder bed fusion (EB-PBF) in longitudinal and cross orientation. The in vitro cytotoxicity assay shows that TiO2 nanotubes produced on EB-PBF in longitudinal and cross orientation showed non-cytotoxic activity with viability percentages exceeding 85% in L929 and MG-63 cell lines. Additionally, moderate ROS and NO production from RAW 264.7 murine macrophages confirm TiO2 nanotubes cytocompatibility. In cell adhesion assays, active living MG-63 cells with a strong green fluorescence signal, lamellipodia structures and mitotic rounded-cells, were seen in both TiO2 nanotubes produced on EB-PBF in longitudinal and cross orientation. From the results of our experimental work, there are no significant differences in the cellular behavior of TiO2 nanotubes produced on Ti6Al4V samples manufactured via electron beam powder bed fusion (EB-PBF) in longitudinal or cross orientation. The significance of this work lies in clarifying how an important processing variable in additive manufacturing build orientation impacts the biological performance of nanostructured implant surfaces.