Department of Polymer Materials, Shanghai University, 99 Shangda Road, Shanghai 200444, P. R. China.
Biomater Sci. 2018 Sep 25;6(10):2738-2749. doi: 10.1039/c8bm00705e.
Shape memory scaffolds are minimally invasive cell carriers that are promising biomaterials for tissue regeneration. Since cell fate is critical for successful regeneration, the influence of mechanostructural stimuli induced by shape memory on cell fate is worthy of investigation. In this study, we developed a poly(l-glutamic acid)-based (PLGA-based) shape memory porous scaffold by cross-linking PLGA with poly(ε-caprolactone)-diols (PCL-diols) and by using the particle leaching method. After regulating the cross-linking density and molecular weight of the PCL-diols, the scaffolds exhibited excellent shape memory properties around physiological temperatures. The interconnected porous structure not only enabled the scaffold to be deformed to 20% of its original size but also supported tissue invasion. In vivo results demonstrated that the PLGA-based scaffold degraded within 6 months. Cell fate studies indicated that large dimensional deformation of the porous structure during the shape memory process induced significant death, detachment and reorganization of stem cells but had negligible effects on stemness and proliferation. These results indicate that the PLGA-based shape memory porous scaffold is a potential cell carrier for tissue regeneration, and they are also meaningful to investigate the effects of mechanostructural stimuli on stem cell fate in porous structures.
形状记忆支架是微创细胞载体，是组织再生有前途的生物材料。由于细胞命运对成功再生至关重要，因此值得研究由形状记忆引起的机械结构刺激对细胞命运的影响。在这项研究中，我们通过用聚（ε-己内酯）-二醇（PCL-二醇）交联聚（L-谷氨酸）-（PLGA）并使用颗粒溶出法开发了一种基于聚（L-谷氨酸）的（基于 PLGA 的）形状记忆多孔支架。通过调节 PCL-二醇的交联密度和分子量，支架在生理温度下表现出出色的形状记忆性能。互连成孔结构不仅使支架能够变形为原始尺寸的 20%，而且还支持组织侵入。体内结果表明，PLGA 基支架在 6 个月内降解。细胞命运研究表明，多孔结构在形状记忆过程中的大尺寸变形会导致干细胞的大量死亡、脱落和重组，但对干细胞特性和增殖几乎没有影响。这些结果表明，基于 PLGA 的形状记忆多孔支架是组织再生的潜在细胞载体，对于研究机械结构刺激对多孔结构中干细胞命运的影响也具有重要意义。
