Active matter flows and self-organization inside of cells*

The organized movement of intracellular material is part of the functioning of cells and the development of organisms. These flows can arise from the action of molecular machines on the flexible, and often transitory, scaffoldings of the cell. That sounds complex and multiscaled, as is much of biology, but its study is also becoming a beautiful sub-branch of biophysical fluid dynamics characterized by geometric complexity, confinement, and microscale activity. Understanding phenomena in this realm has necessitated the development of new simulation tools, and of new coarse-grain mathematical models to analyze and simulate. In that context, I'll discuss how a symmetry-breaking "swirling" instability of a motor-laden cytoskeleton may be an important part of the development of an oocyte, and what models of active, immersed polymers tell us about chromatin dynamics in the nucleus.