# Focusing and sorting of ellipsoidal magnetic particles in microchannels

## TL;DR

This paper introduces a method to control and sort ellipsoidal magnetic particles in microchannels using a static magnetic field, enabling precise particle positioning for lab-on-a-chip applications.

## Contribution

The study demonstrates a novel approach combining magnetic fields and hydrodynamic interactions for particle focusing and segregation in microfluidic devices.

## Key findings

- Magnetic fields can pin particle orientation effectively.
- Hydrodynamic interactions enable size and shape-based segregation.
- The method is applicable for particle manipulation in lab-on-a-chip systems.

## Abstract

We present a simple method to control the position of ellipsoidal magnetic particles in microchannel Poiseuille flow using a static uniform magnetic field. The magnetic field is utilized to pin the particle orientation, and the hydrodynamic interactions between ellipsoids and channel walls allow control of the transverse position of the particles. We employ a far-field hydrodynamic theory and simulations using the boundary element method and Brownian dynamics to show how magnetic particles can be focussed and segregated by size and shape. This is of importance for particle manipulation in lab-on-a-chip devices.