Shape memory thermoplastic polyurethane (TPU)/poly(ε-caprolactone) (PCL) blends as self-knotting sutures

Area of Science:

• Materials Science
• Polymer Science
• Biomedical Engineering

Background:

• Thermally responsive shape memory polymers are valuable for biomedical applications.
• Developing efficient methods to create these polymers is crucial.

Purpose of the Study:

• To prepare and characterize thermoplastic polyurethane (TPU)/poly(ε-caprolactone) (PCL) blends with shape memory properties.
• To investigate the underlying mechanisms of their shape memory behavior.
• To assess their suitability for biomedical applications.

Main Methods:

• Melt compounding of TPU and PCL using a twin-screw extruder.
• Injection molding of the polymer blends at various ratios.
• Characterization of shape memory properties using multiple test methods.
• Assessment of cell viability and interactions on the blends.

Main Results:

• The blend with 25% TPU and 75% PCL demonstrated optimal shape memory performance (98% shape fixing, 90% shape recovery).
• Good miscibility between TPU and PCL was observed, with enhanced PCL crystallinity in the blend.
• The blend exhibited potential for suture applications due to its ability to self-knot.
• High viability and active substrate-cell interactions were confirmed for 3T3 fibroblast cells on the blends.

Conclusions:

• TPU/PCL blends offer promising shape memory characteristics for biomedical uses.
• The hybrid crystalline/amorphous structure of the 25% TPU/75% PCL blend is key to its shape memory performance.
• The biocompatibility of these blends supports their potential in medical devices and sutures.