One-step modification of nano-hydroxyapatite coating on titanium surface by hydrothermal method

Since metallic biomaterials used for orthopedic and dental implants possess a paucity of reactive functional groups, bioactivity modification of these materials is challenging. To enhance osteoconductivity, sandblasted and acid etched titanium (SLA-Ti) discs were hydrothermally treated in simple suspension of hydroxyapatite (HA) by a one-step method in the present work. Change of surface chemistry, surface morphology of samples, and structure of formed nano-HA were investigated by X-ray photoelectron spectrometry (XPS), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray powder diffraction (XRD). The results demonstrated that the concentration of hydroxyl groups increased after hydrothermal treatment. The ability of the titanium surface to form nano-HA was enhanced by increasing the hydrothermal treatment temperature and time. The bonding strength of the formed nano-HA coating, examined by an ultrasonic cleaning process, was higher than that of HA coating generated directly by HA suspension deposition. Culturing of MC3T3-E1 cells on the SLA-Ti and HT-Ti discs in vitro showed that HT-Ti was more favorable for cell attachment and differentiation than SLA-Ti. Hence the one-step hydrothermal treatment with HA suspension was a simple, effective and promising method for HA coating modification of titanium implants.