Basic study for the controlling of the dispersion and the agglomeration of magnetic particles

The effective way of controlling the dispersion and the agglomeration of the magnetic particles is desired for the medical treatment such as magnetic hyperthermia and drug delivery system using magnetic particles. In this study, we propose the principle of a new method of controlling them. If we use the magnetic particles with magnetic anisotropy, the particles can be rotated by the magnetic torque generated by the rotational magnetic field. When the rotating agglomerated particles are subjected to the fluid pressure, the agglomeration is parted into pieces and dispersed due to the increase of the drug force from the fluid. We found that it is important to control the Coulomb force between the particles by surface coating. As a basic study using the two magnetic particles, we confirmed the condition that the aggregated two small magnets get isolated experimentally with changing the thickness of the coating layer and the rotational frequency.