Three-dimensional mathematical modelling of magnetic bead interactions within a magnetic separation system

Magnetic separation relates to the ability to separate particles based on their magnetic mobilities. This is often limited by the formation of bead agglomerates. Bead agglomerates are formed as a result of attractive magnetic induced interactions among magnetic beads suspended in fluid. A three-dimensional model of the interactions among three equal sized super-paramagnetic beads suspended in a static fluid within a uniform magnetic field is presented here. The beads' trajectories were recorded on video while the relative axial displacement of the bead was obtained using the recorded off-focus images. A good agreement was obtained by comparing the beads' simulated trajectories with the video data. Therefore, the model is able to predict the behaviour of magnetic beads in immunoassays as well as magnetic separation system.