Enhanced osteogenesis properties of titanium implant materials by highly uniform mesoporous thin films of hydroxyapatite and titania intermediate layer.

Titanium (Ti) has been widely used for medical and dental applications; however, bare Ti cannot be properly connected to a living bone, and hence some modifications are needed for this purpose. The present study describes the synthesis of mesoporous hydroxyapatite thin films (MHF) on titanium implant materials for speeding up and shortening the processes of osteointegration. The uniform MHF was coated on a Ti substrate following the insertion of intermediate titania (TiO) film via the sol-gel dip-coating method. The intermediate titania layer improved the bonding strength between the MHF and Ti substrate. MHFs were synthesized using a precursor solution containing phosphoric acid, calcium nitrate tetrahydrate, and a nonionic surfactant (CE) as the phosphate source, calcium source, and structure-directing agent, respectively. The effect of calcination temperature on phase composition, morphology, microstructure, roughness, and wettability of the MHFs was investigated using XRD, FE-SEM, COM, AFM, and contact angle measurement. The XRD results revealed the crystalline hydroxyapatite phase, which was improved with an increase in the calcination temperature. Moreover, the FE-SEM images showed the crack-free MHFs, uniform thickness of the layer, and mesoporous surface morphology. In addition, it was found that the roughness and wettability of the samples change upon the alteration of calcination temperature. The biological studies demonstrated that MHFs support the adhesion and proliferation of the mesenchymal stem cells (MSCs) and guid them toward osteogenic differentiation. Therefore, the MHFs prepared in this study may be useful in a wide range of applications, particularly in bone regeneration medicine.