Improvement of biomedical functionality of titanium by ultrasound-assisted electrophoretic deposition of hydroxyapatite-graphene oxide nanocomposites

Herein, we improved the biomedical functionality of titanium by deposition of hydroxyapatite (HA)-graphene oxide (GO) nanocomposites using the ultrasound-assisted electrophoretic technique. Ti sheets were anodized in a well-optimized condition and subsequently were coated in suspensions of HA-GO with various compositions (0, 1, and 3 wt% of GO). Hardness, crack resistance, adhesion, hydrophilicity, corrosion, and bioactivity of the coatings were evaluated. The results showed that the addition of GO substantially improves the mechanical properties, particularly coating with 1 wt% GO demonstrated the best-reported adhesion strength so far (3.65 +/- 0.33Gpa). The integration of GO in the coatings also leads to an enhancement in the hydrophilicity of the Ti, with 3 wt% GO coating reaching a very low contact angle of 31 degrees. The corrosion resistance of the sample coated with 1 wt% GO was higher than that of sample without GO. However, further addition of GO (3 wt%) deteriorated the corrosion resistance. Finally, the coating with 1 wt% GO presented excellent bioactivity behavior, as its Ca/P ratio (1.62) was very close to that of natural bone (1.67).