Department of Biomedical Engineering, Texas A&M University, College Station, Texas 77843, USA.
Department of Materials Science and Engineering, Texas A&M University, College Station, Texas 77843, USA.
J Mater Chem B. 2024 Apr 17;12(15):3694-3702. doi: 10.1039/d4tb00050a.
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.
由可紫外光固化的聚（ε-己内酯）（PCL）大分子单体制备的温敏形状记忆聚合物（SMPs）具有制备自贴合骨支架、自扩张阴道支架和其他形状变化装置的潜力。为了确保在展开过程中的组织安全性，形状致动温度（，即 PCL 的熔融转变温度或 ）必须从由 -PCL-DA（～10kgmol）制备的支架中观察到的约 55°C 降低。此外，提高生物降解速率将是有利的，有助于骨组织愈合，并有可能消除对支架取回的需求。在此，制备了一系列的六种可紫外光固化的 PCL 大分子单体，具有 或 4 臂 结构， s 分别为 10、7.5 和 5kgmol，随后将其制备成六种多孔支架组合物（10k、7.5k、5k、10k★、7.5k★和 5k★）溶剂浇铸颗粒沥滤（SCPL）。由 -PCL-四丙烯酸酯（-PCL-TA）大分子单体制备的支架在降低 时表现出明显的 降低，而用相应的 -PCL-二丙烯酸酯（-PCL-DA）大分子单体制备的支架则降低了 。制备了具有所需降低的 分布的支架：37°C< <55°C（自贴合骨支架）和 ≤37°C（自扩张支架）。随着大分子单体 降低，交联密度增加，而 %结晶度降低，特别是用 -PCL-TA 大分子单体制备的支架。尽管保留了形状记忆行为并增加了径向扩张压力，但这导致了模量的降低，但同时也提高了降解速率。
