Nano-fibrous scaffolding promotes osteoblast differentiation and biomineralization
Nano-fibrous scaffolding promotes osteoblast differentiation and biomineralization
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DOI：
10.1016/j.biomaterials.2006.06.013
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发表时间：
2007-01-01
期刊：
影响因子：
14
通讯作者：
Ma, Peter X.
中科院分区：
文献类型：
--
作者：
Woo, Kyung Mi;Jun, Ji-Hae;Ma, Peter X.
纳米纤维聚乳酸（PLLA）支架具有相互连接的孔隙，其假设是纳米纤维支架可以模仿胶原原纤维的形态功能，为细胞创造比固体壁支架更有利的微环境。在这项研究中，利用体外系统比较纳米纤维支架与固体壁支架的生物学特性，以研究其在骨组织工程中的潜在应用。与固体壁支架相比，纳米纤维支架上的生物矿化作用明显增强，这一点通过von Kossa染色、钙含量测量和透射电镜证实。为了支持这一发现，与固体壁支架相比，在纳米纤维支架上培养的成骨细胞表现出更高的碱性磷酸酶活性和更早且增强的成骨细胞表型表达。与固体壁支架相比，纳米纤维支架培养的细胞中runx2蛋白和骨唾液蛋白mRNA的表达明显增加。在培养的第1天，α 2和β 1整合素以及α v和β 3整合素在纳米纤维支架上的细胞表面高表达，与此相关的是细胞裂解物中磷酸化paxillin和磷酸化fak的水平较高。相比之下，在固体壁支架上播种的细胞表达的这些整合素、phospho-Paxillin和phospho-FAK的水平显著降低。为了进一步研究纳米纤维结构的作用，我们通过在培养物中添加3,4-脱氢脯氨酸来抑制胶原原纤维的形成，然后检测细胞中α 2整合素的表达。在脱氢脯氨酸存在的情况下，纳米纤维支架上的细胞持续表达α 2整合素，而固体壁支架上的细胞明显抑制α 2整合素。这些结果提供了初步证据，表明合成纳米纤维可能表现出与天然胶原纤维相当的某些特性，因此，纳米纤维结构可能作为一种优于固体壁结构的支架，促进成骨细胞分化和生物矿化。(c) 2006 Elsevier Ltd.版权所有。
Nano-fibrous poly(L-lactic acid) (PLLA) scaffolds with interconnected pores were developed under the hypothesis that nano-fibrous scaffolding would mimic a morphological function of collagen fibrils to create a more favorable microenvironment for cells versus solid-walled scaffolds. In this study, an in vitro system was used to examine biological properties of the nano-fibrous scaffolds compared with those of solid-walled scaffolds for their potential use in bone tissue engineering. Biomineralization was enhanced substantially on the nano-fibous scaffolds compared to solid-walled scaffolds, and this was confirmed by von Kossa staining, measurement of calcium contents, and transmission electron microscopy. In support of this finding, osteoblasts cultured on the nano-fibrous scaffolds exhibited higher alkaline phosphatase activity and an earlier and enhanced expression of the osteoblast phenotype versus solid-walled scaffolds. Most notable were the increases in runx2 protein and in bone sialoprotein mRNA in cells cultured on nano-fibrous scaffolds versus solid-walled scaffolds. At the day 1 of culture, alpha 2 and beta 1 integrins as well as alpha v and beta 3 integrins were highly expressed on the surface of cells seeded on nano-fibrous scaffolds, and linked to this were higher levels of phospho-Paxillin and phospho-FAK in cell lysates. In contrast, cells seeded on solid-walled scaffolds expressed significantly lower levels of these integrins, phospho-Paxillin, and phospho-FAK. To further examine the role of nano-fibrous architecture, we inhibited the formation of collagen fibrils by adding 3,4-dehydroproline to cultures and then assayed cells for expression of alpha 2 integrin. Cells seeded on nano-fibrous scaffolds sustained expression of alpha 2 integrin in the presence of dehydroproline, while suppression of alpha 2 integrin was evident in cells seeded on solid-walled scaffolds. These results provide initial evidence that synthetic nano fibers may exhibit certain properties that are comparable to natural collagen fibers, and thus, the nano-fibrous architecture may serve as a superior scaffolding versus solid-walled architecture for promoting osteoblast differentiation and biomineralization. (c) 2006 Elsevier Ltd. All rights reserved.