Biodegradable and Bioactive Orthopedic Magnesium Implants with Multilayered Protective Coating

Area of Science:

• Biomaterials Science
• Orthopedic Engineering
• Materials Science

Background:

• Magnesium (Mg) and its alloys are promising biodegradable orthopedic implant materials.
• Rapid corrosion of Mg implants limits their functional lifespan in vivo.
• Effective corrosion protection is crucial for Mg-based orthopedic applications.

Purpose of the Study:

• To develop a multilayered coating for magnesium implants to reduce corrosion rates.
• To evaluate the biocompatibility and bone growth promotion of coated Mg implants.
• To investigate the effect of coating composition and thickness on Mg corrosion.

Main Methods:

• Fabrication of a composite material with a Mg substrate and a multilayered coating (chemical conversion layer, adhesion layer, polylactic acid).
• Corrosion testing in simulated body fluid (SBF) to measure weight loss and Mg2+ ion release.
• In vivo implantation in Sprague-Dawley rats for bone defect repair, followed by X-ray, micro-CT, and histological analysis.

Main Results:

• The multilayered coating reduced the corrosion rate of Mg implants to 1/10th of bare Mg.
• Corrosion rate was tunable by altering the chemical conversion layer type and polylactic acid thickness.
• In vivo studies demonstrated improved anticorrosion and enhanced bone growth with the coated implants.

Conclusions:

• The innovative multilayered coating effectively protects biodegradable magnesium implants against rapid corrosion.
• The coated Mg implants exhibit excellent biocompatibility and promote bone growth.
• This technology offers a viable solution for developing functional biodegradable orthopedic implants.