Abstract

Motile cilia are slender, flexible organelles used by cells across eukaryotic life to move and manipulate surrounding fluids. In this talk, I will describe and use two modelling approaches to probe cilia dynamics at both the individual and collective levels. At the individual level, I will present a study where we make of use the follower-force model to explore the internal structural properties of cilia. I will show how even modest values of bending modulus anisotropy can eliminate 3D states, allowing only 2D planar beating to emerge.

At the collective level, I will present results examining the emergence and coordination of cilia on a spherical surface using a model ciliate akin to the well-studied algae colony Volvox. Here, we make use of a modelling framework that we refer to as the filament oscillator model. Its defining feature is that the cilia are governed by just two dynamic variables, but retain their filament-like shape. We find that for sufficiently flexible cilia, there is bistability between symplectic and diaplectic metachronal waves. I will discuss this result, as well as characterise the resulting propulsive capabilities of these emergent states.