Characterisation and in vitro bioactivity of anodised titanium and hydroxyapatite as implants for biomedical application

Naturally, titanium (Ti) has bioinert surface which is a non-preferred nucleation site for bone-like apatite. Therefore, this study aimed to modify bioinert to bioactive Ti using anodic oxidation in different electrolytes and pair Ti with HAP in SBF (new approach SBF). Besides that, there are also other novelties including ultraviolet (UV) light treatment, UV irradiation during SBF (UV-SBF) and prediction of anodised titanium properties. The anodisation parameters such as type of electrolyte and it concentration, applied voltage, and current density were varied. Meanwhile, HAP was mixed with binders, polyvinyl alcohol (PVA) and polyethylene glycol (PEG), and sintered at 1000-1200°C. The anodised Ti films were characterised based on it colour, morphology, mineralogy, cross-section view, and wettability. Various SBF approaches were used such as traditional SBF, UV-SBF and new approach SBF (pairing). The selected anodised Ti has undergone other testing including UV treatment and bioactivity test. The conceptual models that explain the changes in the morphology as a function of the experimental parameters were developed using the data as well as the prediction of anodised Ti properties. For the anodisation in C2H4O2, there were three stages of oxide growth based on films properties. The data showed that the SP solution could produce better bioactive Ti, followed by SBC and SN. For HAP, the binders did not give any significant effect on HAP properties due to PVA and PEG were burnt off at high sintering temperature (> 700°C) Increasing the mechanical strength of HAP has led to low porosity. Anodised Ti with high crystalline of anatase and/or rutile, porous, and superhydrophilic enable better deposition of thick apatite on the Ti surface. Furthermore, the smooth Ti surface lacked nucleation sites for bone-like apatite growth. The new approach of pairing in SBF has produced weak bonding strength that bonded anodised Ti and HAP without fixation device. After 7 days in SBF, apatite bridge (thin layer) is formed between anodised Ti and HAP surfaces. The results are important to predict in vivo mechanism after completing the implementation process