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

Biocompatible poly(propylene carbonate) (PPC)/polycaprolactone (PCL) shape memory blends were fabricated using melt blending. The shape memory performance of these blends was found to depend remarkably on their components. On addition of 25 vol % PCL, one blend (PL-25) achieved an optimal shape-fixing ratio (Rf) and -recovery ratio (Rr). Specifically, its Rr considerably increased by 24.1 and 50.0% compared with those of pure PPC and PCL, respectively, because of the restricted irreversible deformation of the amorphous chains cross-linked by tiny crystals. After undergoing three thermomechanical cycles, Rf and Rr reached 97.0%. The PL-25 blend was further melt-processed into a stent, which showed a fast response and self-expansion at 37 °C. These results, along with those obtained from evaluating the material's blood compatibility, in vitro degradation and drug release behavior, demonstrated the great potential of PL-25 for biomedical applications.