Biocompatible Shape Memory Blend for Self-Expandable Stents with Potential Biomedical Applications

Area of Science:

• Materials Science
• Biomedical Engineering
• Polymer Science

Background:

• Biocompatible polymers are crucial for medical devices.
• Shape memory polymers offer unique advantages for applications like stents.
• Poly(propylene carbonate) (PPC) and polycaprolactone (PCL) are known for their biocompatibility.

Purpose of the Study:

• To fabricate and characterize biocompatible poly(propylene carbonate)/polycaprolactone (PPC/PCL) shape memory blends.
• To optimize the shape memory performance of PPC/PCL blends for biomedical applications.
• To evaluate the potential of a specific blend (PL-25) for use in self-expanding stents.

Main Methods:

• Melt blending was used to fabricate PPC/PCL shape memory blends.
• Shape memory performance was assessed by measuring shape-fixing (Rf) and shape-recovery (Rr) ratios.
• The optimal blend (PL-25) was processed into a stent and its performance at 37 °C was evaluated.
• Blood compatibility, in vitro degradation, and drug release behavior were also assessed.

Main Results:

• The PL-25 blend, containing 25 vol % PCL, exhibited optimal shape memory properties.
• PL-25 showed significantly improved Rr (24.1% over PPC, 50.0% over PCL) due to crystal-induced chain restriction.
• After three cycles, Rf and Rr reached 97.0%.
• The PL-25 stent demonstrated fast response and self-expansion at body temperature (37 °C).

Conclusions:

• The PL-25 blend offers superior shape memory performance compared to pure PPC and PCL.
• The blend's excellent shape memory characteristics, biocompatibility, and degradation profile make it highly suitable for biomedical applications.
• The PL-25 blend shows significant promise for the development of advanced self-expanding stents.