Increased osteoblast adhesion on titanium-coated hydroxylapatite that forms CaTiO₃

CaTiO₃ is a strong candidate to form at the interface between hydroxylapatite (HA) and titanium implants during many coating procedures. However, few studies have compared the cytocompatibility properties of CaTiO₃ to HA pertinent for bone-cell function. For this reason, the objective of the present in vitro study was to determine the ability of bone-forming cells (osteoblasts) to adhere on titanium coated with HA that resulted in the formation of CaTiO₃. To accomplish the formation of CaTiO₃, titanium was coated on HA discs and annealed either under air or a N₂+H₂ environment. Materials were characterized by X-ray diffraction (XRD), Rutherford back-scattering spectroscopy (RBS), and atomic force microscopy (AFM). These characterization techniques demonstrated the formation of a nanometer rough CaTiO₃ layer as a consequence of interactions between HA and titanium during coating conditions. Results from cytocompatibility tests revealed increased osteoblast adhesion on materials that contained CaTiO₃ compared to both pure HA and uncoated titanium. The greatest osteoblast adhesion was observed on titanium-coated HA annealed under air conditions. Because adhesion is a crucial prerequisite to subsequent functions of osteoblasts (such as the deposition of calcium containing mineral), the present in vitro results imply that orthopedic coatings that form CaTiO₃ could increase osseointegration with juxtaposed bone needed for increased implant efficacy.