Hydrodynamic synchronization of autonomously oscillating optically trapped particles

TL;DR

This study demonstrates how ellipsoidal colloidal particles trapped by lasers can spontaneously oscillate and synchronize through hydrodynamic interactions, providing insights into biological cilia synchronization.

Contribution

The paper presents experimental and modeling evidence of hydrodynamic synchronization in optically trapped ellipsoidal particles, highlighting their potential as a model for biological cilia.

Findings

Synchronization depends on particle distance and orientation.

Anisotropic hydrodynamic coupling leads to strongest synchronization along oscillation direction.

Experimental results are well reproduced by a phenomenological model.

Abstract

Ellipsoidal micron-sized colloidal particles can oscillate spontaneously when trapped in a focused laser beam. If two oscillating particles are held in proximity their oscillations synchronize through hydrodynamic interactions. The degree of synchronization depends on the distance between the oscillators and on their orientation. Due to the anisotropic nature of hydrodynamic coupling the synchronization is strongest when particles are arranged along the direction of oscillations. Similar behavior is observed for many oscillating particles arranged in a row. Experimental observations are well reproduced with a model that uses a phenomenological description of the optical force and hydrodynamic interactions. Our results show that oscillating ellipsoidal particles can serve as a model system for studying hydrodynamic synchronization between biological cilia.