Improving the bioactivity and corrosion resistance properties of electrodeposited hydroxyapatite coating by dual doping of bivalent strontium and manganese ion

The key property in the preparation of a biomaterial is to facilitate the regeneration and/or replacement of injured organs and tissues. To obtain such a biomaterial, strontium and manganese co-substituted hydroxyapatite (SrMnHA) ceramic coatings on commercially pure titanium (CP-Ti) were successfully prepared by a cathodic electrodeposition method. The formation of SrMnHA coating was investigated using Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis and inductively coupled plasma. Co-doping of Sr2 + and Mn2 + ions decreased hydroxyapatite unit cell volume and grain sizes. Obtained coatings were crack-free and dense, which led to the decrease in the corrosion current densities of CP-Ti in physiological solutions. The dissolution tests performed on SrMnHA resulted in the leaching of Sr2 + and Mn2 + at low levels. SrMnHAs have moderately hydrophilic surfaces with a contact angle of 23.8°. Additionally, the MC3T3-E1 cells show better cell morphology, adhesion, spreading, proliferation and expression of alkaline phosphatase on SrMnHA than on HA. The excellent biocompatibility of SrMnHA is mainly attributed to a probable effect of a combination of good surface wettability and ion release (Sr2 + and Mn2 +). Results suggest that SrMnHA composite-coated CP-Ti can be a potential candidate for orthopaedic applications.