Biodegradable WE43 Mg alloy/hydroxyapatite interpenetrating phase composites with reduced hydrogen evolution.

Area of Science:

• Biomaterials Science
• Orthopedic Engineering
• Materials Science

Background:

• Biodegradable magnesium implants offer bone repair advantages but suffer from gas accumulation, limiting clinical use.
• Reducing magnesium mass via porosity decreases strength and degradation resistance.
• Developing strategies to mitigate gas generation and maintain mechanical integrity is crucial.

Purpose of the Study:

• To create novel biodegradable magnesium/hydroxyapatite interpenetrating phase composites.
• To evaluate the gas generation, mechanical properties, and biocompatibility of these composites.
• To address the limitations of current porous magnesium implants for bone regeneration.

Main Methods:

• Additive manufacturing of WE43 Mg alloy scaffolds with 75% porosity.
• Infiltration with calcium phosphate cement and subsequent hydrothermal treatment.
• Degradation testing to measure hydrogen gas evolution and mechanical property assessment.

Main Results:

• The magnesium/hydroxyapatite composites generated an order of magnitude less hydrogen gas than pure WE43 scaffolds.
• Composites exhibited 1.8 times greater compressive strength than scaffolds, comparable to cancellous bone.
• Enhanced degradation resistance was observed due to magnesium passivation, supporting osteoblast proliferation.

Conclusions:

• The developed interpenetrating phase composites show significant potential for biodegradable osteosynthesis devices.
• Optimized hydrothermal processing is key to balancing strength and degradation rates.
• This approach offers a promising solution to overcome gas accumulation issues in magnesium implants.