Size-dependent particle migration and trapping in 3D microbubble streaming flows

TL;DR

This study demonstrates that acoustically actuated microbubbles can selectively manipulate microparticles in 3D flows, enabling size-dependent migration and trapping useful for particle separation and sorting.

Contribution

It provides experimental evidence and a flow-based model showing size-sensitive particle migration in 3D microbubble streaming flows, a novel approach for particle manipulation.

Findings

Particles exhibit size-dependent migration and trapping.

Flow modeling reproduces particle trajectories accurately.

Three regimes of migratory behavior based on particle size.

Abstract

Acoustically actuated sessile bubbles can be used as a tool to manipulate microparticles, vesicles and cells. In this work, using acoustically actuated sessile semi-cylindrical microbubbles, we demonstrate experimentally that finite-sized microparticles undergo size-sensitive migration and trapping towards specific spatial positions in three dimensions with high reproducibility. The particle trajectories are successfully reproduced by passive advection of the particles in a steady three-dimensional streaming flow field augmented with volume exclusion from the confining boundaries. For different particle sizes, this volume exclusion mechanism leads to three regimes of qualitatively different migratory behavior, suggesting applications for separating, trapping, and sorting of particles in three dimensions.