Evaluating Polylactic Acid and Basalt Fibre Composites as a Potential Bioabsorbable Stent Material

Area of Science:

• Biomaterials Engineering
• Polymer Science
• Medical Device Development

Background:

• Permanent metallic stents pose long-term clinical risks.
• Bioabsorbable polymer stents (BPSs) offer a solution but have lower mechanical properties.
• Polylactic acid (PLA) based BPSs require larger struts, risking delayed healing and thrombosis.

Purpose of the Study:

• To enhance the mechanical performance of PLA by incorporating basalt fibers.
• To optimize twin-screw extrusion processing conditions for PLA/basalt fiber composites.
• To achieve significant mechanical improvements at minimal fiber loadings.

Main Methods:

• PLA/basalt fiber composites were prepared using twin-screw extrusion at varying screw speeds (50, 200, 350 RPM).
• Composites underwent single and double extrusion runs to assess processing effects.
• Characterization included ash content, tensile testing, Scanning Electron Microscopy (SEM), and rheometry.

Main Results:

• Lower screw speeds (50 RPM) improved fiber dispersion and minimized molecular weight reduction.
• A second extrusion run enhanced dispersion, increasing tensile strength and modulus.
• Optimal conditions (10% fiber loading, 50 RPM, double extrusion) yielded a 20.23% increase in tensile strength and 27.52% increase in modulus.
• Processing conditions critically influenced fiber dispersion, matrix adhesion, and molecular weight retention.

Conclusions:

• Optimized processing of PLA/basalt fiber composites can significantly enhance mechanical properties for BPS applications.
• Careful control of extrusion parameters is crucial for balancing mechanical enhancement with material integrity.
• This approach offers a promising strategy to overcome the mechanical limitations of current bioabsorbable polymer stents.