研究论文
Biodegradable Magnesium-Zinc-Calcium Alloys with Hydroxyapatite Coating for Load-Bearing Orthopedic Implants
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摘要
Biodegradable metallic implants offer the promise of eliminating secondary removal surgeries. This study develops a Mg-4Zn-0.5Ca (wt%) alloy with a micro-arc oxidation (MAO) / electrodeposited hydroxyapatite (HA) bilayer coating to simultaneously control degradation rate and promote osteointegration. The bilayer-coated alloy exhibits a corrosion rate of 0.42 mm/year in simulated body fluid — a 78% reduction compared to the bare alloy — while maintaining a compressive yield strength of 215 MPa suitable for cancellous bone fixation. In vivo rabbit femoral condyle implantation over 24 weeks demonstrates complete bone bridging with 92% new bone contact ratio and no hydrogen-gas-induced cavities. Serum Mg²⁺ levels remain within the physiological range throughout the degradation period.