Johns Hopkins University, Dept. Physics and Astronomy, Baltimore, USA.
Johns Hopkins University, Dept. Mechanical Engineering, Baltimore, USA.
Soft Matter. 2021 Jun 28;17(24):5878-5887. doi: 10.1039/d1sm00100k. Epub 2021 Mar 12.
Many cell types spontaneously order like nematic liquid crystals, and, as such, they form topological defects, which influence the cell organization. While defects with topological charge ±1/2 are common in cell monolayers, defects with charge ±1, which are thought to be relevant in the formation of protrusions in living systems, are more elusive. We use topographical patterns to impose topological charge of ±1 in controlled locations in cell monolayers. We study two types of cells, 3T6 fibroblasts and EpH-4 epithelial cells, and we compare their behavior on such patterns, characterizing the degree of alignment, the cell density near the defects, and their behavior at the defect core. We observe density variation in the 3T6 monolayers near both types of defects over the same length-scale. By choosing appropriate geometrical parameters of our topographical features, we identify a new behavior of 3T6 cells near the defects with topological charge +1, leading to a change in the cells' preferred shape. Our strategy allows a fine control of cell alignment near defects as a platform to study liquid crystalline properties of cells.
许多细胞类型会自发地有序排列，类似于向列型液晶，因此它们会形成拓扑缺陷，从而影响细胞组织。虽然具有拓扑电荷 ±1/2 的缺陷在细胞单层中很常见，但具有电荷 ±1 的缺陷（被认为与活系统中突起的形成有关）则更为难以捉摸。我们使用拓扑图案在细胞单层的受控位置施加 ±1 的拓扑电荷。我们研究了两种类型的细胞，即 3T6 成纤维细胞和 EpH-4 上皮细胞，并比较了它们在这些图案上的行为，特征在于对齐程度、缺陷附近的细胞密度以及它们在缺陷核心处的行为。我们观察到在具有相同长度尺度的两种类型缺陷附近的 3T6 单层中存在密度变化。通过选择我们拓扑特征的适当几何参数，我们在具有拓扑电荷 +1 的缺陷附近识别出 3T6 细胞的一种新行为，导致细胞的首选形状发生变化。我们的策略允许在缺陷附近精细控制细胞对齐，作为研究细胞向列液晶性质的平台。
