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Electrodeposition of hydroxyapatite coating on Mg‐4.0Zn‐1.0Ca‐0.6Zr alloy and in vitro evaluation of degradation, hemolysis, and cytotoxicity
Author(s) -
Guan RenGuo,
Johnson Ian,
Cui Tong,
Zhao Tong,
Zhao ZhanYong,
Li Xue,
Liu Huinan
Publication year - 2012
Publication title -
journal of biomedical materials research part a
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.849
H-Index - 150
eISSN - 1552-4965
pISSN - 1549-3296
DOI - 10.1002/jbm.a.34042
Subject(s) - materials science , alloy , metallurgy , corrosion , microstructure , ultimate tensile strength , scanning electron microscope , coating , energy dispersive x ray spectroscopy , nuclear chemistry , composite material , chemistry
A novel biodegradable Mg‐4.0Zn‐1.0Ca‐0.6Zr (wt %) alloy was successfully produced using a series of metallurgical processes; including melting, casting, rolling, and heat treatment. The hardness and ultimate tensile strength of the alloy sheets increased to 71.2HV and 320 MPa after rolling and then aging for 12 h at 175°C. These mechanical properties were sufficient for load‐bearing orthopedic implants. A hydroxyapatite (HA) coating was deposited on the Mg‐4.0Zn‐1.0Ca‐0.6Zr (wt %) alloy using a novel coating process combining alkali heat pretreatment, electrodeposition, and alkali heat posttreatment. The microstructure, composition, and phases of the Mg‐4.0Zn‐1.0Ca‐0.6Zr (wt %) alloy and HA coating were characterized using scanning electron microscopy (SEM), energy dispersive X‐ray spectroscopy (EDS), and X‐ray diffraction (XRD). The degradation, hemolysis, and cytocompatibility of the HA‐coated and uncoated Mg‐4.0Zn‐1.0Ca‐0.6Zr (wt %) alloy were studied in vitro . The corrosion potential ( E corr ) of Mg‐4.0Zn‐1.0Ca‐0.6Zr alloy (−1.72 V) was higher than Mg (−1.95 V), Mg‐0.6Ca alloy (−1.91 V) and Mg‐1.0Ca alloy (−1.97 V), indicating the Mg‐Zn‐Ca‐Zr alloy would be more corrosion resistant. The initial corrosion potential of the HA‐coated Mg alloy sample (−1.51 V) was higher than the uncoated sample (−1.72 V). The hemolysis rates of the HA‐coated and uncoated Mg‐4.0Zn‐1.0Ca‐0.6Zr (wt %) alloy samples were both <5%, which met the requirements for implant materials. The HA‐coated and uncoated Mg‐4.0Zn‐1.0Ca‐0.6Zr (wt %) alloy samples demonstrated the same cytotoxicity score as the negative control. The HA‐coated samples showed a slightly greater relative growth rate (RGR%) of fibroblasts than the uncoated samples. Both the HA‐coated and uncoated Mg‐4.0Zn‐1.0Ca‐0.6Zr (wt %) alloy provided evidence of acceptable cytocompatibility for medical applications. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2012.