Contribution of the dipole–dipole interaction to targeting efficiency of magnetite nanoparticles inside the blood vessel: A computational modeling analysis with different magnet geometries

Abstract

The widespread use of magnetite nanoparticles inside the bloodstream for diagnostic and therapeutic purposes has made the influence of the interaction forces between these nanoparticles an important issue for predicting their behavior for improving the effectiveness of the protocols. Magnets with various geometries have been used in different biomedical applications, such as targeted drug delivery, to guide drugs carrying magnetite nanoparticles to specific areas. In this regard, using computational modeling, we have employed a multiphysics modeling approach using the particle tracing module in the COMSOL software environment to investigate the behavior of magnetite nanoparticles considering not only the magnetophoretic force, but also the dipole–dipole interaction forces between the nanoparticles. The effects of different geometries of magnets on the induced magnetic flux density and the laminar flow velocity inside the bloodstream were studied as well. The results of our study show that each geometry of the magnet induces different magnetic flux density profile and laminar velocity inside the blood flow. The behavior of ferrofluid flow is dependent on the geometry of the magnet and its remanent flux density. By increasing the size of magnetic nanoparticles, the magnetophoretic force enhances the particle velocity in the direction perpendicular to the vessel's walls, which could result in pull out. The results also reveal that the magnetic dipole–dipole interactions between nanoparticles could lead to the induction of higher dipole–dipole interaction forces in regions close to the magnet, especially on the upper wall of the blood vessel.