Department of Pediatrics, Qilu Hospital of Shandong University , Jinan, Shandong 250100, China.
Institute for Advanced Interdisciplinary Research, Jinan University , Jinan, Shandong 250100, China.
ACS Appl Mater Interfaces. 2017 Oct 4;9(39):33717-33727. doi: 10.1021/acsami.7b13313. Epub 2017 Sep 22.
It is well-accepted that most osteogenic differentiation processes do need growth factors assistance to improve efficiency. As a material cue, hydroxyapatite (HAp) can promote osteogenic differentiation of stem cells only in a way. Up to now, rare work related to the relationship between HAp nanostructures and stem cells in osteogenic differentiation process without the assistance of growth factors has been reported. In this study, one-dimensional (1D) HAp nanostructures with tunable length were synthesized by an oleic acid assisted solvothermal method by adjusting the alcohol/water ratio (η). The morphology of 1D HAp nanostructures can be changed from long nanowires into nanorods with the η value change. Different substrates constructed by 1D HAp nanostructures were prepared to investigate the effect of morphology of nanostructured HAp on stem cell fate without any growth factors or differentiation induce media. Human adipose-derived stem cells (hADSCs), a kind of promising stem cell for autologous stem cell tissue engineering, were used as the stem cell model. The experiments prove that HAp morphology can determine the performance of hADSCs cultured on different substrates. Substrate constructed by HAp nanorods (100 nm) is of little benefit to osteogenic differentiations. Substrate constructed on HAp long nanowires (50 μm) causes growth and spread inhibition of hADSCs, which even causes most cells death after 7 days of culture. However, substrate constructed by HAp short nanowires (5 μm) can destine the hADSCs differentiation to osteoblasts efficiently in normal medium (after 3 weeks) without any growth factors. It is surprise that hADSCs have changed to polyhedral morphology and exhibited the tendency to osteogenic differentiation after only 24 h culture. Hydroxyapatite nanostructures mediated stem cell osteogenic differentiation excluding growth factors provides a powerful cue to design biomaterials with special nanostructures, and helps to elucidate the interaction of stem cell and biomaterials nanostructures. The results from this study are promising for application in bone tissue engineering.
人们普遍认为，大多数成骨分化过程确实需要生长因子的辅助来提高效率。作为一种材料线索，羟基磷灰石（HAp）只能以一种方式促进干细胞的成骨分化。到目前为止，很少有关于在没有生长因子辅助的情况下，HAp 纳米结构与成骨分化过程中的干细胞之间关系的相关工作被报道。在这项研究中，通过调节醇/水比（η），使用油酸辅助的溶剂热法合成了具有可调长度的一维（1D）HAp 纳米结构。1D HAp 纳米结构的形态可以从长纳米线通过η 值的变化转变为纳米棒。通过 1D HAp 纳米结构制备了不同的基底，以研究纳米结构 HAp 的形态对没有任何生长因子或分化诱导介质的干细胞命运的影响。人脂肪来源的干细胞（hADSCs）是一种很有前途的自体干细胞组织工程用干细胞，被用作干细胞模型。实验证明，HAp 形态可以决定在不同基底上培养的 hADSCs 的性能。由 HAp 纳米棒（100nm）构建的基底对成骨分化没有好处。在 HAp 长纳米线（50μm）上构建的基底会抑制 hADSCs 的生长和扩散，甚至会导致培养 7 天后大部分细胞死亡。然而，在正常培养基（3 周后）中，由 HAp 短纳米线（5μm）构建的基底可以有效地将 hADSCs 分化为成骨细胞，而无需任何生长因子。令人惊讶的是，在仅培养 24 小时后，hADSCs 就变成了多面体形，并表现出向成骨细胞分化的趋势。不添加生长因子的情况下，HAp 纳米结构介导的干细胞成骨分化为设计具有特殊纳米结构的生物材料提供了一个强大的线索，并有助于阐明干细胞与生物材料纳米结构的相互作用。这项研究的结果有望应用于骨组织工程。
