Polylactic acid/hydroxyapatite composite filaments: Balancing printability, mechanical integrity, and osteogenic...

Area of Science:

• Biomaterials Science
• Additive Manufacturing
• Tissue Engineering

Background:

• Biomedical devices for bone repair necessitate materials with balanced printability, structural integrity, and biological performance.
• Additive manufacturing is increasingly utilized for fabricating these devices, often employing poly(lactic acid) (PLA) as a biodegradable polymer matrix.

Purpose of the Study:

• To fabricate and evaluate poly(lactic acid) (PLA) composite filaments with varying hydroxyapatite (HAp) contents for extrusion-based bone tissue engineering.
• To determine the optimal HAp loading for achieving a balance between processability, structural integrity, and osteogenic performance.

Main Methods:

• PLA composite filaments with 0, 5, 10, 20, and 30 wt% HAp were fabricated using a solvent-assisted non-solvent-induced precipitation method.
• Physicochemical, rheological, mechanical, and biological properties were evaluated.
• Thermal analysis (glass transition and cold crystallization temperatures) was performed.

Main Results:

• Increasing HAp content negatively impacted filler dispersion homogeneity, leading to agglomeration and microvoids at 30 wt%.
• Intermediate HAp incorporation (5-10 wt%) demonstrated the most favorable balance of properties.
• PLA-HAp10 composites exhibited enhanced alkaline phosphatase (ALP) activity and osteogenic gene expression, alongside reliable filament formation and scaffold printability.

Conclusions:

• Hydroxyapatite (HAp) content significantly influences the performance of PLA composites for bone tissue engineering.
• Optimal HAp loading (5-10 wt%) is critical for achieving desired printability, mechanical reinforcement, and osteogenic response.
• Careful control of HAp concentration is essential for developing effective PLA-based biomaterials for bone repair applications.