The load-response of the flagellar beat

TL;DR

This study quantifies the force-velocity relationship of flagellar beating in Chlamydomonas, linking mechanical efficiency to synchronization ability, using experiments and a theoretical model.

Contribution

It introduces a quantitative measurement of flagellar force-velocity dynamics and connects mechanical efficiency with synchronization in oscillatory flows.

Findings

Force-velocity relationship characterized experimentally.

A theoretical model accurately reproduces the observed relationship.

Link established between mechanical efficiency and flow synchronization.

Abstract

Cilia and flagella exhibit regular bending waves that perform mechanical work on the surrounding fluid, to propel cellular swimmers and pump fluids inside organisms. Here, we quantify a force-velocity relationship of the beating flagellum, by exposing flagellated \emph{Chlamydomonas} cells to controlled microfluidic flows. A simple theory of flagellar limit-cycle oscillations, calibrated by measurements in the absence of flow, reproduces this relationship quantitatively. We derive a link between the chemo-mechanical efficiency of the flagellar beat and its ability to synchronize to oscillatory flows.