-PCL shape memory polymer (SMP) scaffolds with tunable transition temperatures for enhanced utility.

Thermoresponsive shape memory polymers (SMPs) prepared from UV-curable poly(ε-caprolactone) (PCL) macromers have the potential to create self-fitting bone scaffolds, self-expanding vaginal stents, and other shape-shifting devices. To ensure tissue safety during deployment, the shape actuation temperature (, the melt transition temperature or of PCL) must be reduced from ∼55 °C that is observed for scaffolds prepared from -PCL-DA ( ∼ 10 kg mol). Moreover, increasing the rate of biodegradation would be advantageous, facilitating bone tissue healing and potentially eliminating the need for stent retrieval. Herein, a series of six UV-curable PCL macromers were prepared with or 4-arm architectures and with s of 10, 7.5, and 5 kg mol, and subsequently fabricated into six porous scaffold compositions (10k, 7.5k, 5k, 10k★, 7.5k★, and 5k★) solvent casting particulate leaching (SCPL). Scaffolds produced from -PCL-tetraacrylate (-PCL-TA) macromers produced pronounced reductions in with decreased those formed with the corresponding -PCL-diacrylate (-PCL-DA) macromers. Scaffolds were produced with the desired reduced profiles: 37 °C < < 55 °C (self-fitting bone scaffold), and ≤ 37 °C (self-expanding stent). As macromer decreased, crosslink density increased while % crystallinity decreased, particularly for scaffolds prepared from -PCL-TA macromers. While shape memory behavior was retained and radial expansion pressure increased, this imparted a reduction in modulus but with an increase in the rate of degradation.