Cell response and bone ingrowth to 3D printed Ti6Al4V scaffolds with Mg-incorporating sol-gel Ta₂O₅ coating

In recent years, additive manufacturing techniques have been used to fabricate 3D titanium (Ti)-based scaffolds for production of desirable complex shapes. However, insufficient osteointegration of porous Ti-based scaffolds can elicit long-term complications (e.g., aseptic loosening) and need further revision surgery. In this study, a magnesium (Mg)-incorporating tantalum (Ta) coating was deposited on a 3D Ti6Al4V scaffold using a sol-gel method for enhancing its osteogenic properties. To evaluate the biofunction of this surface, bone mesenchymal stem cells and rabbit femoral condyle were used to assess the cell response and bone ingrowth, respectively. Ta₂O₅ coatings and Mg-incorporating Ta₂O₅ coatings were both homogeneously deposited on porous scaffolds. In vitro studies revealed that both coatings exhibit enhanced cell proliferation, ALP activity, osteogenic gene expression and mineralization compared with the uncoated Ti6Al4V scaffold. Especially for Mg-incorporating Ta₂O₅ coatings, great improvements were observed. In vivo studies, including radiographic examination, fluorochrome labeling and histological evaluation also followed similar trends. Also, bone ingrowth to scaffolds with Mg-incorporating Ta₂O₅ coatings exhibited the most significant increase compared with uncoated and Ta₂O₅ coated scaffolds. All the above results indicate that Mg-doped Ta₂O₅ coatings are an effective tool for facilitating osteointegration of conventional porous Ti6Al4V scaffolds.