Putting hydrodynamic interactions to work: tagged particle separation

TL;DR

This paper proposes a novel method for separating magnetically tagged cells by actively using hydrodynamic interactions induced by a rotating magnetic field, enabling large-scale sorting.

Contribution

It introduces a new approach where hydrodynamic interactions are harnessed actively for cell separation, contrasting with previous passive roles.

Findings

Hydrodynamic interactions can be used actively for particle separation.

The method is theoretically modeled and supported by numerical simulations.

Suitable for large-scale cell sorting applications.

Abstract

Separation of magnetically tagged cells is performed by attaching markers to a subset of cells in suspension and applying fields to pull from them in a variety of ways. The magnetic force is proportional to the field gradient, and the hydrodynamic interactions play only a passive, adverse role. Here we propose using a homogeneous rotating magnetic field only to make tagged particles rotate, and then performing the actual separation by means of hydrodynamic interactions, which thus play an active role. The method, which we explore here theoretically and by means of numerical simulations, lends itself naturally to sorting on large scales.