Boffito Monica, Sirianni Paolo, Di Rienzo Anna Maria, Chiono Valeria
Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, Turin, Italy.
J Biomed Mater Res A. 2015 Mar;103(3):1276-90. doi: 10.1002/jbm.a.35253. Epub 2014 Jun 25.
This review focuses on the challenges associated with the design and development of injectable hydrogels of synthetic origin based on FDA approved blocks, such as polyethylene glycol (PEG) and poly(ɛ-caprolactone) (PCL). An overview of recent studies on inverse thermosensitive PEG/PCL hydrogels is provided. These systems have been proposed to overcome the limitations of previously introduced degradable thermosensitive hydrogels [e.g., PEG/poly(lactide-co-glycolic acid) hydrogels]. PEG/PCL hydrogels are advantageous due to their higher gel strength, slower degradation rate and availability in powder form. Particularly, triblock PEG/PCL copolymers have been widely investigated, with PCL-PEG-PCL (PCEC) hydrogels showing superior gel strength and slower degradation kinetics than PEG-PCL-PEG (PECE) hydrogels. Compared to triblock PEG/PCL copolymers, concentrated solutions of multiblock PEG/PCL copolymers were stable due to their slower crystallization rate. However, the resulting hydrogel gel strength was low. Inverse thermosensitive triblock PEG/PCL hydrogels have been mainly applied in tissue engineering, to decrease tissue adherence or, in combination with bioactive molecules, to promote tissue regeneration. They have also found application as in situ drug delivery carriers. On the other hand, the wide potentialities of multiblock PEG/PCL hydrogels, associated with the stability of their water-based solutions under storage, their higher degradation time compared to triblock copolymer hydrogels and the possibility to insert bioactive building blocks along the copolymer chains, have not been fully exploited yet. A critical discussion is provided to highlight advantages and limitations of currently developed themosensitive PEG/PCL hydrogels, suggesting future strategies for the realization of PEG/PCL-based copolymers with improved performance in the different application fields.
本综述聚焦于基于美国食品药品监督管理局（FDA）批准的嵌段（如聚乙二醇（PEG）和聚（ε-己内酯）（PCL））设计和开发合成来源可注射水凝胶所面临的挑战。提供了关于温敏性PEG/PCL水凝胶的近期研究概述。这些体系已被提出用于克服先前引入的可降解温敏性水凝胶（如PEG/聚（丙交酯-共-乙交酯）水凝胶）的局限性。PEG/PCL水凝胶具有优势，因为它们具有更高的凝胶强度、更慢的降解速率且有粉末形式。特别是，三嵌段PEG/PCL共聚物已得到广泛研究，PCL-PEG-PCL（PCEC）水凝胶比PEG-PCL-PEG（PECE）水凝胶表现出更高的凝胶强度和更慢的降解动力学。与三嵌段PEG/PCL共聚物相比，多嵌段PEG/PCL共聚物的浓溶液由于其较慢的结晶速率而稳定。然而，所得水凝胶的凝胶强度较低。温敏性三嵌段PEG/PCL水凝胶主要应用于组织工程，以减少组织粘连，或与生物活性分子结合以促进组织再生。它们还被用作原位药物递送载体。另一方面，多嵌段PEG/PCL水凝胶具有广泛的潜力，与其水基溶液在储存时的稳定性、与三嵌段共聚物水凝胶相比更长的降解时间以及沿共聚物链插入生物活性构建块的可能性相关，但尚未得到充分利用。本文进行了批判性讨论，以突出当前开发的温敏性PEG/PCL水凝胶的优点和局限性，提出未来策略以实现具有不同应用领域中改进性能的基于PEG/PCL的共聚物。
