Meinig School of Biomedical Engineering, College of Engineering, Cornell University, 277 Kimball Hall, 134 Hollister Drive, Ithaca, NY, 14853, USA.
Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, 14853, USA.
Adv Mater. 2020 Oct;32(43):e2003761. doi: 10.1002/adma.202003761. Epub 2020 Sep 22.
Widely present in nature and in manufactured goods, elastomers are network polymers typically crosslinked by strong covalent bonds. Elastomers crosslinked by weak bonds usually exhibit more plastic deformation. Here, chelation as a mechanism to produce biodegradable elastomers is reported. Polycondensation of sebacic acid, 1,3-propanediol, and a Schiff-base (2-[[(2-hydroxyphenyl) methylene]amino]-1,3-propanediol) forms a block copolymer that binds several biologically relevant metal ions. Chelation offers a unique advantage unseen in conventional elastomer design because one ligand binds multiple metal ions, yielding bonds of different strengths. Therefore, one polymeric ligand coordinated with different metal ions produces elastomers with vastly different characteristics. Mixing different metal ions in one polymer offers another degree of control on material properties. The density of the ligands in the block copolymer further regulates the mechanical properties. Moreover, a murine model reveals that Fe crosslinked foam displays higher compatibility with subcutaneous tissues than the widely used biomaterial-polycaprolactone. The implantation sites restore to their normal architecture with little fibrosis upon degradation of the implants. The versatility of chelation-based design has already shown promise in hydrogels and highly stretchy nondegradable polymers. The biodegradable elastomers reported here would enable new materials and new possibilities in biomedicine and beyond.
弹性体广泛存在于天然产物和人工制品中，通常是通过强共价键交联的网络聚合物。通过弱键交联的弹性体通常表现出更多的塑性变形。在这里，报道了一种通过螯合作用制备可生物降解弹性体的方法。癸二酸、1,3-丙二醇和席夫碱（2-[[（2-羟基苯基）亚甲基]氨基]-1,3-丙二醇）的缩聚形成一种嵌段共聚物，可结合多种生物相关的金属离子。螯合作用提供了一种在传统弹性体设计中看不到的独特优势，因为一个配体可以结合多个金属离子，从而产生不同强度的键。因此，一种与不同金属离子配位的聚合物配体可以产生具有截然不同特性的弹性体。在一种聚合物中混合不同的金属离子可以提供对材料性能的另一种控制程度。嵌段共聚物中配体的密度进一步调节机械性能。此外，在一个鼠模型中，交联铁的泡沫显示出比广泛使用的生物材料聚己内酯更高的与皮下组织的相容性。在植入物降解后，植入部位的组织结构恢复正常，纤维化程度很小。基于螯合作用的设计的多功能性已经在水凝胶和高拉伸不可降解聚合物中显示出了前景。这里报道的可生物降解弹性体将在生物医学和其他领域为新材料和新可能性提供可能。
