Computational Simulations of Magnetic Particle Capture in Arterial Flows

The aim of Magnetic Drug Targeting (MDT) is to concentrate drugs, attached to magnetic particles, in a specific part of the human body by applying a magnetic field. Computational simulations are performed of blood flow and magnetic particle motion in a left coronary artery and a carotid artery, using the properties of presently available magnetic carriers and strong superconducting magnets (up to B $\approx$ 2 T). For simple tube geometries it is deduced theoretically that the particle capture efficiency scales as $\eta \sim \sqrt{\textrm{Mn}_p}$ , with $\textrm{Mn}_p$ the characteristic ratio of the particle magnetization force and the drag force. This relation is found to hold quite well for the carotid artery. For the coronary artery, the presence of side branches and domain curvature causes deviations from this scaling rule, viz. $\eta \sim \textrm{Mn}_p ^ {\beta}$, with $\beta>1/2$. The simulations demonstrate that approximately a quarter of the inserted 4 $\mu$m particles can be captured from the bloodstream of the left coronary artery, when the magnet is placed at a distance of 4.25 cm. When the same magnet is placed at a distance of 1 cm from a carotid artery, almost all of the inserted 4 $\mu$m particles are captured. The performed simulations, therefore, reveal significant potential for the application of MDT to the treatment of atherosclerosis