Scheme: Newton International Fellowships
Organisation: University of Cambridge
Dates: Mar 2013-Mar 2015
Summary: I joined the Cavendish Laboratory in 2013 thanks to a Newton International Fellowship awarded by the Royal Society to work in the area of biological and soft matter, with a focus on the role of the synchronization in biological flows. This research project focused in the hydrodynamic coupling of ciliated epithelial cells and the emergence of “metachronal waves”.
The coordinated cyclic beating of eukaryotic cilia and flagella is responsible for vital functions such as motility of microorganisms and fluid transport close to various epithelial tissues. Synchronization induced by hydrodynamic interactions is a possible and potentially general mechanism behind this coordinated beating of cilia that generates complex wave-like patterns called metachronal waves. These dynamical states are essential in life, transporting nutrients and clearing pathogens. How these collective states arise is not fully understood, but it is clear that individual cilia are interacting mechanically, with a strong and long-range component of the coupling mediated by the viscosity or viscoelasticity of the fluid, and resulting in the transport of fluid by periodic beating, through remarkably organized behaviour in space and time. Nevertheless, up to date, it is not known how these spatiotemporal patterns emerge and what sets their properties. At the relevant scales and temperatures, coupling has the same magnitude as the random thermal forces; yet the synchronised states of cilia are very stable, implying that a robust physical mechanism must exist to allow this. Here, rather than a realistic beating filament description, I used a simple model with a minimal number of degrees of freedom, based on optically driven colloidal particles that can act as micron-scale phase rotors, elucidating the role of spatial distribution of cilia, fluid viscoelasticity and external flows, aiming to understand the parameters that result in collective beating.