Complex Tissue Regeneration Department, MERLN Institute for Technology Inspired Regenerative Medicine, Maastricht University, Universiteitssingel 40, 6229 ER Maastricht, The Netherlands.
Aachen-Maastricht Institute for Biobased Materials (AMIBM), Maastricht University, P.O. Box 616, 6200 MD Maastricht, The Netherlands.
Biomacromolecules. 2022 Mar 14;23(3):1083-1100. doi: 10.1021/acs.biomac.1c01417. Epub 2022 Jan 20.
α-Amino acid based polyester amides (PEAs) are promising candidates for additive manufacturing (AM), as they unite the flexibility and degradability of polyesters and good thermomechanical properties of polyamides in one structure. Introducing α-amino acids in the PEA structure brings additional advantages such as (i) good cytocompatibility and biodegradability, (ii) providing strong amide bonds, enhancing the hydrogen-bonding network, (iii) the introduction of pendant reactive functional groups, and (iv) providing good cell-polymer interactions. However, the application of α-amino acid based PEAs for AM via fused deposition modeling (FDM), an important manufacturing technique with unique processing characteristics and requirements, is still lacking. With the aim to exploit the combination of these advantages in the creation, design, and function of additively manufactured scaffolds using FDM, we report the structure-function relationship of a series of α-amino acid based PEAs. The PEAs with three different molecular weights were synthesized via the active solution polycondensation, and their performance for AM applications was studied in comparison with a commercial biomedical grade copolymer of l-lactide and glycolide (PLGA). The PEAs, in addition to good thermal stability, showed semicrystalline behavior with proper mechanical properties, which were different depending on their molecular weight and crystallinity. They showed more ductility due to their lower glass transition temperature (; 18-20 °C) compared with PLGA (57 °C). The rheology studies revealed that the end-capping of PEAs is of high importance for preventing cross-linking and further polymerization during the melt extrusion and for the steadiness and reproducibility of FDM. Furthermore, our data regarding the steady 3D printing performance, good polymer-cell interactions, and low cytotoxicity suggest that α-amino acid based PEAs can be introduced as favorable polymers for future AM applications in tissue engineering. In addition, their ability for formation of bonelike apatite in the simulated body fluid (SBF) indicates their potential for bone tissue engineering applications.
基于α-氨基酸的聚酯酰胺（PEAs）是增材制造（AM）的有前途的候选材料，因为它们将聚酯的柔韧性和可降解性以及聚酰胺的良好热机械性能结合在一个结构中。在 PEA 结构中引入α-氨基酸带来了额外的优势，例如（i）良好的细胞相容性和生物降解性，（ii）提供强酰胺键，增强氢键网络，（iii）引入侧挂反应性官能团，以及（iv）提供良好的细胞-聚合物相互作用。然而，基于α-氨基酸的 PEAs 通过熔融沉积建模（FDM）用于 AM 的应用仍然缺乏，FDM 是一种具有独特加工特性和要求的重要制造技术。为了利用 FDM 在增材制造支架的创建、设计和功能方面的这些优势，我们报告了一系列基于α-氨基酸的 PEAs 的结构-功能关系。通过活性溶液缩聚合成了三种不同分子量的 PEAs，并与商业生物医学级左旋乳酸和乙交酯共聚物（PLGA）进行了比较，研究了它们在 AM 应用中的性能。除了良好的热稳定性外，PEAs 还表现出半结晶行为，具有适当的机械性能，其性能取决于分子量和结晶度。与 PLGA（57°C）相比，它们的玻璃化转变温度（18-20°C）较低，因此具有更高的延展性。流变学研究表明，PEAs 的端基封端对于防止熔融挤出过程中的交联和进一步聚合以及 FDM 的稳定性和可重复性非常重要。此外，我们关于稳定的 3D 打印性能、良好的聚合物-细胞相互作用和低细胞毒性的数据表明，基于α-氨基酸的 PEAs 可以作为组织工程中未来 AM 应用的有利聚合物引入。此外，它们在模拟体液（SBF）中形成类骨磷灰石的能力表明它们具有用于骨组织工程应用的潜力。
