title: Electrodeposition of Ca-P coatings on biodegradable Mg alloy: in vitro biomineralization behavior.
abstract: Preparing stabilized apatite on biodegradable Mg alloy may improve biocompatibility and promote osteointegration. In the present work, three kinds of Ca-P coatings, brushite (DCPD, CaHPO(4).2H(2)O), hydroxyapatite (HA, Ca(10)(PO(4))(6)(OH)(2)) and fluoridated hydroxyapatite (FHA, Ca(5)(PO(4))(3)(OH)(1-)(x)F(x)) are fabricated by electrodeposition on a biodegradable Mg-Zn alloy. The crystalline structures, morphologies and compositions of these Ca-P coatings have been characterized by X-ray diffrection, scanning electron microscopy and energy-dispersive spectoscopy. The effects of these coatings on the degradation behavior and mineralization activity of the Mg-Zn alloy have also been investigated. The experimental results showed that these coatings decreased the degradation rate of Mg-Zn alloy, while the precipitates on the uncoated and DCPD-coated Mg-Zn alloy in modified simulated biological fluid had low Ca/P molar ratios, which delayed bone-like apatite formation. Both the HA and FHA coating could promote the nucleation of osteoconductive minerals (bone-like apatite or beta-TCP) for 1month. However, the HA coating transformed from DCPD through alkali heat treatment was fragile and less stable, and therefore its long-term corrosion resistance was not satisfactory. Instead, the FHA was more stable and had better corrosion resistance, and thus it should be better suited as a coating of Mg implants for orthopedic applications.
authors.affiliation: State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Song
authors.forename: Shaoxiang
authors.initials: S
authors.lastname: Zhang
authors.forename: Jianan
authors.initials: J
authors.lastname: Li
authors.forename: Changli
authors.initials: C
authors.lastname: Zhao
authors.forename: Xiaonong
authors.initials: X
authors.lastname: Zhang
mesh_terms: D000497:Alloys / Q000494:pharmacology*; D002113:Calcification, Physiologic / Q000187:drug effects*; D002130:Calcium Phosphates / Q000494:pharmacology*; D020099:Coated Materials, Biocompatible / Q000494:pharmacology*; D004595:Electroplating / Q000379:methods*; D006859:Hydrogen / Q000032:analysis; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D008274:Magnesium / Q000494:pharmacology*; D008855:Microscopy, Electron, Scanning; D014961:X-Ray Diffraction; D015032:Zinc / Q000494:pharmacology
chemical_list: D000497:Alloys; D002130:Calcium Phosphates; D020099:Coated Materials, Biocompatible; D006859:Hydrogen; C020243:calcium phosphate; D008274:Magnesium; D015032:Zinc