title: Fabrication and characterization of bioactive composite coatings on Mg-Zn-Ca alloy by MAO/sol-gel.
abstract: High corrosion rate and accumulation of hydrogen gas upon degradation impede magnesium alloys' clinical application as implants. In this work, micro-arc oxidation (MAO) was used to fabricate a porous coating on magnesium alloys as an intermediate layer to enhance the bonding strength of propolis layer. Then the composite coatings were fabricated using sol-gel method by dipping sample into the solution containing propolis and polylactic acid at 40 °C. The corrosion resistance of the samples was determined based on potentiodynamic polarization experiments and immersion tests. Biocompatibility was designed by observing the attachment and growth of wharton's jelly-derived mesenchymal stem cells (WJCs) on substrates with MAO coating and substrates with composite coatings. The results showed that, compared with that of Mg-Zn-Ca alloy, the corrosion current density of the samples with composite coatings decreased from 5.37 × 10⁻⁵ to 1.10 × 10⁻⁶ A/cm² and the corrosion potential increased by 240 mV. Composite coatings exhibit homogeneous corrosion behavior and can promote WJCs cell adhesion and proliferation. In the meantime, pH value was relatively stable during the immersion tests, which may be significant for cellular survival. In conclusion, our results indicate that composite coatings on Mg-Zn-Ca alloy fabricated by MAO/sol-gel method provide a new type bioactive material.
authors.affiliation: Materials Research Center, School of Materials Science and Engineering, Zhengzhou University, Zhenzhou 450002, People's Republic of China.
authors.forename: J H
authors.initials: JH
authors.lastname: Gao
authors.forename: X Y
authors.initials: XY
authors.lastname: Shi
authors.forename: B
authors.initials: B
authors.lastname: Yang
authors.forename: S S
authors.initials: SS
authors.lastname: Hou
authors.forename: E C
authors.initials: EC
authors.lastname: Meng
authors.forename: F X
authors.initials: FX
authors.lastname: Guan
authors.forename: S K
authors.initials: SK
authors.lastname: Guan
mesh_terms: D000497:Alloys / Q000737:chemistry*; D001672:Biocompatible Materials; D002118:Calcium / Q000737:chemistry*; D018929:Cell Culture Techniques; D049109:Cell Proliferation; D055664:Electrochemical Techniques; D006801:Humans; D008274:Magnesium / Q000737:chemistry*; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000502:physiology; D008855:Microscopy, Electron, Scanning; D010084:Oxidation-Reduction; D013499:Surface Properties; D015032:Zinc / Q000737:chemistry*
chemical_list: D000497:Alloys; D001672:Biocompatible Materials; D008274:Magnesium; D015032:Zinc; D002118:Calcium