Electrodeposition of Ca–P coatings on biodegradable Mg alloy: In vitro biomineralization behavior

✍ Scribed by Yang Song; Shaoxiang Zhang; Jianan Li; Changli Zhao; Xiaonong Zhang

• Publisher: Elsevier Science
• Year: 2010
• Tongue: English
• Weight: 726 KB
• Volume: 6
• Category: Article
• ISSN: 1742-7061
• DOI: 10.1016/j.actbio.2009.12.020

✦ Synopsis

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 Á2H 2 O), hydroxyapatite (HA, Ca 10 (PO 4 ) 6 (OH) 2 ) and fluoridated hydroxyapatite (FHA, Ca 5 (PO 4 ) 3 (OH) 1Àx 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 b-TCP) for 1 month. 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.