Stem cells are adherent cells whose multipotency and differentiation can be regulated by numerous microenvironmental signals including soluble growth factors and surface topography. This study describes a simple method for creating distinct micropatterns via microphase separation resulting from polymer demixing of poly(desaminotyrosyl-tyrosine carbonate) (PDTEC) and polystyrene (PS). Substrates with co-continuous (ribbons) or discontinuous (islands and pits) PDTEC regions were obtained by varying the ratio of PDTEC and sacrificial PS. Human mesenchymal stem cells (MSCs) cultured on co-continuous PDTEC substrates for 3 days in bipotential adipogenic/osteogenic (AD/OS) induction medium showed no change in cell morphology but exhibited increased anisotropic cytoskeletal organization and larger focal adhesions when compared to MSCs cultured on discontinuous micropatterns. After 14 days in bipotential AD/OS induction medium, MSCs cultured on co-continuous micropatterns exhibited increased expression of osteogenic markers, whereas MSCs on discontinuous PDTEC substrates showed a low expression of adipogenic and osteogenic differentiation markers. Substrates with graded micropatterns were able to reproduce the influence of local underlying topography on MSC differentiation, thus demonstrating their potential for high throughput analysis. This work presents polymer demixing as a simple, non-lithographic technique to produce a wide range of micropatterns on surfaces with complex geometries to influence cellular and tissue regenerative responses.

Statement of Significance

Gaining a better understanding of how engineered microenvironments influence stem cell differentiation is integral to increasing the use of stem cells and materials in a wide range of tissue engineering applications. In this study, we show the range of topography obtained by polymer demixing is sufficient for investigating how surface topography affects stem cell morphology and differentiation. Our findings show that co-continuous topographies favor early (3-day) cytoskeletal anisotropy and focal adhesion maturation as well as long-term (14-day) expression of osteogenic differentiation markers. Taken together, this study presents a simple approach to pattern topographies that induce divergent responses in stem cell morphology and differentiation.

中文翻译：

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通过聚合物混合产生的基质微图案可调节粘着斑，肌动蛋白各向异性和干细胞的谱系分化

干细胞是贴壁细胞，其多能性和分化可通过多种微环境信号（包括可溶性生长因子和表面形貌）进行调节。这项研究描述了一种通过微相分离来创建独特的微图案的简单方法，该微相分离是由聚（脱氨基酪氨酰酪氨酸碳酸酯）（PDTEC）和聚苯乙烯（PS）的聚合物混合产生的。通过改变PDTEC和牺牲性PS的比例，可以得到具有连续区域（色带）或不连续区域（岛和凹坑）的PDTEC基板。与培养的MSC相比，在双电位成脂/成骨（AD / OS）诱导培养基中在共连续PDTEC底物上培养3天的人间充质干细胞（MSC）的细胞形态没有变化，但表现出各向异性的细胞骨架组织增加和更大的粘着力在不连续的微图案上。在双电势AD / OS诱导培养基中培养14天后，在连续连续的微模式上培养的MSC的成骨标记物表达增加，而在不连续的PDTEC底物上的MSC则显示成脂和成骨分化标记物的低表达。具有渐变微图案的基质能够重现局部基础形貌对MSC分化的影响，从而证明了其在高通量分析中的潜力。这项工作提出了一种简单的聚合物分解方法，

重要声明

更好地了解工程微环境如何影响干细胞分化，这对于在各种组织工程应用中增加干细胞和材料的使用必不可少。在这项研究中，我们显示了通过聚合物混合获得的形貌范围足以研究表面形貌如何影响干细胞的形态和分化。我们的发现表明，共同连续的地形有利于早期（3天）细胞骨架各向异性和粘着斑成熟以及成骨分化标记物的长期（14天）表达。综上所述，这项研究提出了一种简单的方法来绘制图案形貌，从而在干细胞的形态和分化中诱导出不同的反应。