Epithelial cell monolayers show remarkable displacement and velocity
correlations over distances of ten or more cell sizes that are reminiscent of
supercooled liquids and active nematics. We show that many observed features
can be described within the framework of dense active matter, and argue that
persistent uncoordinated cell motility coupled to the collective elastic modes
of the cell sheet is sufficient to produce swirl-like correlations. We obtain
this result using both continuum active linear elasticity and a normal modes
formalism, and validate analytical predictions with numerical simulations of
two agent-based cell models, soft elastic particles and the self-propelled
Voronoi model together with in-vitro experiments of confluent corneal
epithelial cell sheets. Simulations and normal mode analysis perfectly match
when tissue-level reorganisation occurs on times longer than the persistence
time of cell motility. Our analytical model quantitatively matches measured
velocity correlation functions over more than a decade with a single fitting
parameter.

研究表明，上皮细胞单层在长度超过十个细胞大小的距离上表现出类似于超冷液体和活性向列相的位移和速度相关性，这可以在密集活性物质的框架下进行描述，并且通过连续活性线性弹性学和模态分析证实，模拟和模态分析在组织层次时空重组时间大于细胞运动持续时间时是完美匹配的。