论文标题
自由体积理论解释了形态发生过程中粘度的异常行为
Free volume theory explains the unusual behavior of viscosity in a non-confluent tissue during morphogenesis
论文作者
论文摘要
斑马鱼囊胚层形态发生的最新实验表明，非相关胚胎组织的粘度（η）急剧生长，直到临界细胞堆积分数（ϕs）。 η到ϕs的增加与几种玻璃形成材料中观察到的行为相似，这表明细胞动力学是缓慢或类似玻璃的。令人惊讶的是，η是ϕs上方的常数。为了确定η对ϕ的这种不寻常依赖性的机制，我们使用基于代理的密集非对立二维组织进行了广泛的模拟。我们表明，细胞大小中的多分散性以及细胞变形的倾向，导致每个细胞可用区域的饱和度超出关键堆积分数。自由空间中的饱和度不仅解释了上方的粘度高原，而且还提供了平衡几何填料与弛豫动力学急剧增加之间的关系。
A recent experiment on zebrafish blastoderm morphogenesis showed that the viscosity (η) of a non-confluent embryonic tissue grows sharply until a critical cell packing fraction (ϕS). The increase in η up to ϕS is similar to the behavior observed in several glass-forming materials, which suggests that the cell dynamics is sluggish or glass-like. Surprisingly, η is a constant above ϕS. To determine the mechanism of this unusual dependence of η on ϕ, we performed extensive simulations using an agent-based model of a dense non-confluent two-dimensional tissue. We show that polydispersity in the cell size, and the propensity of the cells to deform, results in the saturation of the available free area per cell beyond a critical packing fraction. Saturation in the free space not only explains the viscosity plateau above ϕS but also provides a relationship between equilibrium geometrical packing to the dramatic increase in the relaxation dynamics.
