Extrusion-based additive manufacturing of Mg-Zn/bioceramic composite scaffolds

Area of Science:

• Biomaterials Engineering
• Orthopedic Materials Science
• Additive Manufacturing

Background:

• Femoral nonunion with large segmental bone defects presents a significant clinical challenge.
• Magnesium alloys show promise for bone defect treatment but suffer from rapid degradation.
• Incorporating bioceramics into magnesium alloys can modulate degradation and enhance properties.

Purpose of the Study:

• To develop biodegradable Mg-Zn/bioceramic composite scaffolds using extrusion-based additive manufacturing.
• To optimize ink formulations for 3D printing of porous composite structures.
• To evaluate the biodegradation, mechanical properties, and cytocompatibility of the fabricated scaffolds.

Main Methods:

• Fabrication of Mg-Zn/β-TCP composite inks with varying β-TCP content (5%, 10%, 15%).
• Investigation of ink dispersion and viscoelastic properties for optimal printability.
• 3D printing of porous composite scaffolds and in vitro assessment of degradation, mechanical strength, and cell response.

Main Results:

• Optimized inks enabled the 3D printing of high-density (99% relative density) composite scaffolds.
• Scaffolds with 5% β-TCP exhibited a controlled biodegradation rate of 0.5 mm/y.
• Composite scaffolds showed enhanced elastic moduli and yield strength, mimicking cancellous bone, and improved biocompatibility with preosteoblasts.

Conclusions:

• Extrusion-based additive manufacturing successfully produced Mg-Zn/β-TCP composite scaffolds with tunable properties.
• The developed scaffolds demonstrate a promising combination of controlled biodegradability, bone-like mechanical performance, and enhanced bioactivity.
• These findings highlight the potential of 3D printed Mg-based composites as advanced biodegradable bone substitutes.