Colloidal processing as a successful alternative to produce PLA/Mg composites with tailored mechanical and...

Area of Science:

• Biomaterials Science
• Polymer Science
• Materials Engineering

Background:

• Polylactic acid/magnesium (PLA/Mg) composites show promise for biomedical applications.
• Processing challenges due to high reactivity and biodegradability limit PLA/Mg composite use.
• Surface modification via a colloidal approach with polyelectrolytes offers improved properties.

Purpose of the Study:

• To investigate the benefits of a colloidal processing route for PLA/Mg composites.
• To compare colloidal processing with traditional thermal extrusion.
• To evaluate the impact on mechanical, thermal, and biodegradation properties, and cytocompatibility.

Main Methods:

• Thermal analysis to determine processing parameters.
• Colloidal processing involving polyelectrolyte surface modification.
• Fourier-transform infrared spectroscopy with attenuated total reflectance (FTIR-ATR) to confirm bonding.
• Mechanical testing (compressive strength, elastic modulus).
• Biodegradation studies (hydrogen release, degradation time).
• Cell culture studies using ST2 bone marrow stromal cells.

Main Results:

• Colloidal processing created covalent bonds between PLA and Mg particles, enhancing dispersion.
• Achieved maximum compressive strength of 130 MPa and elastic modulus of 2150 MPa at 25 vol.% Mg loading.
• Reduced hydrogen release by 35%, increased degradation time, and promoted homogeneous degradation.
• Demonstrated cytocompatibility with ST2 cells, showing no adverse effects and promoting 3D cell spreading.

Conclusions:

• Colloidal processing significantly improves PLA/Mg composite properties compared to thermal extrusion.
• Enhanced mechanical strength, controlled biodegradation, and cytocompatibility make these composites suitable for biomedical applications.
• The strong polymer-metal interface formed via colloidal processing is key to improved material performance.