Conditions of hydrodynamic synchronization in models of beating cilia

Motile cilia are highly conserved structures in the evolution of organisms, generating the transport of fluid by periodic beating, through remarkably organized behavior in space and time. It is not known how these spatiotemporal patterns emerge and what sets their properties.

Individual cilia are nonequilibrium systems with many degrees of freedom. However, their description can be represented by simpler effective force laws that drive oscillations, and paralleled with nonlinear phase oscillators studied in physics.

Here I will describe synthetic model phase oscillators, where colloidal particles are driven by optical traps. The complex structural details of the cilia are coarse-grained into the details of how the colloidal particles are driven. We explore experimentally two types of colloidal model, finding in each case the conditions for optimal coupling. The applicability of this approach to biological data is illustrated by successfully mapping the behavior of cilia in the alga Chlamydomonas onto one of the coarse-grained models.