Smith Laura A, Liu Xiaohua, Hu Jiang, Ma Peter X
Department of Biomedical Engineering, The University of Michigan, Ann Arbor, MI 48109-1078, USA.
Biomaterials. 2009 May;30(13):2516-22. doi: 10.1016/j.biomaterials.2009.01.009. Epub 2009 Jan 26.
Embryonic stem cells represent a potentially unlimited cell source for tissue engineering applications. However, in order to be used for such applications, embryonic stem cells' differentiation must be controlled to only the desired lineages. In this study, we examine the effects of nanofibrous architecture and biochemical cues on the osteogenic differentiation of embryonic stem cells compared to the more traditional architecture without the nanofibrous features in two dimensions (thin matrix or flat films) and three dimensions (scaffolds) in vitro. After three weeks of culture the nanofibrous thin matrices were capable of supporting mRNA expression of osteogenic differentiation markers in embryonic stem cells without osteogenic supplements, while solid films required osteogenic supplements and growth factors to achieve mRNA expression of osteogenic differentiation markers. Nanofibrous scaffolds substantially enhanced mRNA expression of osteogenic differentiation markers compared to solid-walled scaffolds, nanofibrous thin matrices or solid films. After 4 weeks of culture, nanofibrous scaffolds were found to contain 3 times more calcium and stronger osteocalcin stain throughout the scaffolds than the solid-walled scaffolds. Overall, the nanofibrous architecture enhanced the osteogenic differentiation and mineralization of embryonic stem cells compared to the solid-walled architecture in both two and three-dimensional cultures.
胚胎干细胞是组织工程应用中一种潜在的无限细胞来源。然而，为了用于此类应用，必须将胚胎干细胞的分化控制在仅所需的谱系。在本研究中，我们在体外二维（薄基质或平膜）和三维（支架）条件下，研究了纳米纤维结构和生化信号对胚胎干细胞成骨分化的影响，并与没有纳米纤维特征的更传统结构进行了比较。培养三周后，纳米纤维薄基质能够在无成骨补充剂的情况下支持胚胎干细胞中成骨分化标志物的mRNA表达，而固体膜则需要成骨补充剂和生长因子才能实现成骨分化标志物的mRNA表达。与实心壁支架、纳米纤维薄基质或固体膜相比，纳米纤维支架显著增强了成骨分化标志物的mRNA表达。培养4周后，发现纳米纤维支架中的钙含量比实心壁支架多3倍，且整个支架中的骨钙素染色更强。总体而言，在二维和三维培养中，与实心壁结构相比，纳米纤维结构增强了胚胎干细胞的成骨分化和矿化。
