Three-dimensional (3D) multicellular cell spheroids (MCSs) are excellent in vitro cell models, in which, e.g., the in vivo cell–cell interaction processes are much better mimicked than in conventional two-dimensional (2D) cell layers. However, the difficulties in the generation of well-defined MCSs with controlled size severely limit their application. Herein, low-adhesive poly(vinyl alcohol) (PVA) hydrogels structured with inverted pyramid-shaped microwells were used to guide the aggregation of cells into MCSs. The cells settling down into the microwells by gravity accumulated at the central tip of the wells and then gradually grew into spheroids. The size of cell spheroids can be straightforwardly controlled by the culture time and initially seeded cell number. The MCSs generated in a parallel microarray format were further used for drug testing. Our results suggest in agreement with complementary literature data that the cell culture format plays a critical role in the cellular response to drugs, and also confirms that spheroids possess a much higher drug resistance than cells in 2D layers. This novel microstructured PVA hydrogel is expected to offer a potential platform for the facile preparation of spheroids for various applications in the biomedical field.

中文翻译：

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三维微结构化聚乙烯醇水凝胶平台，用于多细胞细胞球体的受控形成

三维（3D）多细胞球体（MCS）是出色的体外细胞模型，例如在体内与传统的二维（2D）细胞层相比，细胞间相互作用的过程要好得多。但是，在生成大小可控且定义明确的MCS时遇到的困难严重限制了它们的应用。在本文中，使用具有倒金字塔形微孔的低粘附力聚乙烯醇（PVA）水凝胶来指导细胞向MCSs的聚集。细胞由于重力聚集在孔的中心尖端而沉降到微孔中，然后逐渐长成球形。细胞球体的大小可以通过培养时间和最初接种的细胞数直接控制。以平行微阵列形式产生的MCS被进一步用于药物测试。我们的结果与补充的文献数据相一致，表明细胞培养形式在细胞对药物的反应中起着至关重要的作用，并且还证实了球状体比2D层中的细胞具有更高的耐药性。这种新颖的微结构化PVA水凝胶有望为生物医学领域中各种应用的球体的简便制备提供潜在的平台。