Calcium-deficient hydroxyapatite-PLGA composites: mechanical and microstructural investigation

Area of Science:

• Biomaterials Science
• Materials Engineering
• Composite Materials

Background:

• Calcium deficient hydroxyapatite (CDHAp) and poly(lactide-co-glycolide) (PLGA) composites are promising for biomedical applications.
• Understanding their microstructural and mechanical properties is crucial for optimizing performance.

Purpose of the Study:

• To investigate the microstructural and mechanical properties of CDHAp-PLGA composites.
• To analyze the effect of composition and hydrolysis temperature on composite properties.

Main Methods:

• Composites were synthesized via hydrolysis of alpha-tricalcium phosphate (alpha-TCP) to CDHAp in alpha-TCP-PLGA-NaCl precomposites.
• Isothermal calorimetry and X-ray diffraction monitored hydrolysis.
• Scanning electron microscopy examined microstructural evolution.

Main Results:

• Composites with 80:10:10 wt% alpha-TCP-PLGA-NaCl at 37°C showed tensile strength of 13.3 MPa, flexural strength of 24.8 MPa, and Young's modulus of 2.8 GPa.
• Composites with 60:20:20 wt% showed higher flexural strength (36.1 MPa) and Young's modulus (5.5 GPa), with lower tensile strength (12.0 MPa).
• Mechanical properties varied significantly with both hydrolysis temperature and precomposite composition.

Conclusions:

• The mechanical properties of CDHAp-PLGA composites are strongly influenced by their final microstructure.
• Microstructure is governed by polymer morphology changes around its glass transition temperature and CDHAp formation during hydrolysis.
• Optimizing composition and hydrolysis conditions is key to tailoring the mechanical performance of these biomaterials.