Theoretical comparison of magnetic and hydrodynamic interactions between magnetically tagged particles in microfluidic systems

Magnetic and hydrodynamic interactions between magnetic beads in microfluidic magnetic field gradient filters are compared theoretically and we find that the hydrodynamic interactions are of a longer range and dominate the magnetic ones. Hydrodynamic interactions aid the capturing of particles tagged with magnetic beads as the particles drag each other along, possibly easing requirements on magnetic parameters.