Investigation of biocompatibility and surface properties of surface modified titanium material coated with HA-GO composite by electrophoretic deposition method

Titanium and its alloys are among the most frequently used substrates in biomedical coatings. In order to ensure a healthy osseointegration process, titanium substrates are often coated with hydroxyapatite (HA) material. The aim of this thesis is to improve the surface properties of titanium by different surface treatments and to investigate the effects of graphene oxide (GO) additive on HA-GO composite coating. Surface modification methods are sandblasting, acid etching and finally anodic spark oxidation (ASO) on the etched substrate. After the surface modification procedures, the titanium substrate was coated with HA-GO suspensions at different voltages and times (0, 2, 4 and 6 wt% GO) by electrophoretic deposition (EPD). An optimisation study was carried out in terms of voltage and time. As a result of the optimisation study, the optimum time and voltage were determined as 20 V and 5 min. Surface morphology and elemental content of all produced samples were analysed. Surface morphology, elemental content, contact angle, phase structures, biocompatibility and bioactivity of the coatings produced according to the optimum parameters were investigated. Citotoxicity test was performed on L929 (mouse fibroblast) cell cultures at 70% cell viability. Bioactivity analyses were performed in simulated body fluid (SBF) for 14 days. Contact angle measurements showed that all sample surfaces exhibited superhydrophilic behaviour as a result of the increased surface area due to the ASO treatment. While the contact angle measurement of the sanded substrate was 71.03°, the contact angle values of the HA-GO coatings after ASO and coating process were less than 5°. As a result of the bioactivity test, it was determined that the best result in apatite nucleation was seen in the surface morphology of HA-GO composite coating with 4% GO additive. In the biocompatibility examination with L929 cells, HA-GO (4%) composite coating was the most successful result among HA-GO composite coatings.