The stiffness and topography of a cell's extracellular matrix are physical cues that play a key role in regulating processes that determine cellular fate and function. While substrate stiffness can dictate cell differentiation lineage, migration, and self-organization, topographical features can change the cell's differentiation profile or migration ability. Although both physical cues are present and intrinsic to the native tissuesin vivo,in vitrostudies have been hampered by the lack of technological set-ups that would be compatible with cell culture and characterization.In vitrostudies therefore either focused on screening stiffness effects in cells cultured on flat substrates or on determining topography effects in cells cultured onto hard materials. Here, we present a reliable, microfabrication method to obtain well defined topographical structures of micrometer size (5-10 µm) on soft polyacrylamide hydrogels with tunable mechanical stiffness (3-145 kPa) that closely mimic thein vivosituation. Topographically microstructured polyacrylamide hydrogels are polymerized by capillary force lithography using flexible materials as molds. The topographical microstructures are resistant to swelling, can be conformally functionalized by extracellular matrix proteins and sustain the growth of cell lines (fibroblasts and myoblasts) and primary cells (mouse intestinal epithelial cells). Our method can independently control stiffness and topography, which allows to individually assess the contribution of each physical cue to cell response or to explore potential synergistic effects. We anticipate that our fabrication method will be of great utility in tissue engineering and biophysics, especially for applications where the use of complexin vivo-likeenvironments is of paramount importance.

中文翻译：

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具有独立控制的形貌和刚度的聚丙烯酰胺水凝胶的微细加工。

细胞的细胞外基质的硬度和形貌是物理线索，在调节决定细胞命运和功能的过程中起着关键作用。虽然基质刚度可以决定细胞分化的谱系，迁移和自组织，但地形特征可以改变细胞的分化特征或迁移能力。尽管体内存在着物理线索和天然组织固有的两种物理线索，但由于缺乏与细胞培养和表征兼容的技术设置，体外研究受到了阻碍。因此，体外研究要么着重于筛选培养在其上的细胞的僵硬效应。平坦的基材或确定在硬质材料上培养的细胞中的形貌影响。在这里，我们提出一个可靠的 的微细加工方法，可在具有可调节机械刚度（3-145 kPa）的软聚丙烯酰胺水凝胶上获得精确定义的微米大小（5-10 µm）的形貌结构，该结构紧密模拟体内情况。微观结构的聚丙烯酰胺水凝胶通过毛细管力光刻技术，使用柔性材料作为模具进行聚合。地形微结构可抵抗肿胀，可通过细胞外基质蛋白进行共形功能化，并维持细胞系（成纤维细胞和成肌细胞）和原代细胞（小鼠肠上皮细胞）的生长。我们的方法可以独立控制刚度和地形，从而可以单独评估每种物理提示对细胞反应的贡献或探索潜在的协同效应。