Microwell arrays have emerged as three-dimensional substrates for cell culture due to their simplicity of fabrication and promise for high-throughput applications such as 3D cell-based assays for drug screening. To date, most microwells have had cylindrical geometries. Motivated by our previous findings that cells display 3D physiological characteristics when grown in the spherical micropores of monodisperse foam scaffolds (Lee et al 2013 Integr. Biol. 5 1447-55 and Lin et al 2011 Soft Matter 7 10010-6), here we engineered novel microwells shaped as spherical caps with obtuse polar angles, yielding narrow apertures. When used as bare substrates, these microwells were suitable for culturing cell spheroids; the narrow apertures sterically hindered unattached cultured cells from rolling out of microwells under agitation. When only the walls of the microwell were conjugated with extracellular matrix proteins, cells remained confined in the microwells. Epithelial cells proliferated and burst out of the aperture, and cell polarity was oriented based on the distribution of extracellular matrix proteins in the microwells. Surprisingly, single fibroblast cells in spherical wells of various diameters (40-100 μm) underwent cell-cycle arrest, while cells in circular cylindrical microwells continued to proliferate. Spatial confinement was not sufficient to cause cell-cycle arrest; however, confinement in a constant negative-curvature microenvironment led to cell-cycle arrest. Overall, these investigations demonstrate that this spherical microwell substrate constitutes a novel basic research tool for elucidating how cells respond to dimensionality and microenvironment with radii of curvature at the cellular length scale.

中文翻译：

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球形微孔阵列，用于在3D限制条件下研究单个细胞和微组织。

由于微孔阵列的制造简单性，并有望用于高通量应用，例如用于药物筛选的基于3D细胞的测定法，微孔阵列已成为用于细胞培养的三维基质。迄今为止，大多数微孔具有圆柱形几何形状。根据我们先前的发现，当细胞在单分散泡沫支架的球形微孔中生长时，其细胞具有3D生理特性（Lee等人2013 Integr。Biol。5 1447-55和Lin等人2011 Soft Matter 7 10010-6），在此我们进行了设计新颖的微孔形状呈球形，帽盖具有极角钝角，产生狭窄的孔径。当用作裸底物时，这些微孔适用于培养细胞球体。狭窄的孔在空间上阻碍了未附着的培养细胞在搅拌下滚出微孔。当仅微孔的壁与细胞外基质蛋白偶联时，细胞仍被限制在微孔中。上皮细胞增殖并从孔中爆出，并且根据微孔中细胞外基质蛋白的分布确定细胞极性。出人意料的是，各种直径（40-100μm）的球形孔中的单个成纤维细胞都经历了细胞周期停滞，而圆柱形微孔中的细胞继续增殖。空间限制不足以引起细胞周期停滞。然而，限制在恒定的负曲率微环境中会导致细胞周期停滞。总体，