In recent years physicists have been developing models of non-equilibrium materials, like living cells, that can move and grow. These models typically include physical stresses in a highly stylised phenomenological manner as "direct inputs" to the growth mechanism. Biologists instead understand the decision making process of the cell as something like a chemical computer. A central biochemical oscillator, known as the cell cycle, determines how cells grow and when they divide. The physical stresses serve as input to this biochemical system and it is this that then decides on growth and division. Can these two viewpoints be reconciled?

In a collaboration with colleagues at University of Kyoto in Japan we have shown how the presence of such a biochemical processor has profound consequences for the growth of cells, including the appearance of non-monotonic profiles in the pressure and velocity in growing 2D cell colonies: both features that have been observed in experiment. In this way our work provides a bridge between the biology and physics communities working in this field.

In Mathematical terms our model corresponds to a non-volume conserving fluid in which the volume growth depends on a locally embedded oscillator-sensor, controlled by physical stress. These physical stress can then be self-consistently determined from the growth-induced flows.

This work is in press at Physical Review X as "Role of the cell cycle in collective cell dynamics" by J. Li, S. K. Schnyder, M. S. Turner,* and R. Yamamoto.

• Publication: https://arxiv.org/abs/2012.07647