Computational analysis of magnetic field induced deposition of magnetic particles in lung alveolus in comparison to deposition produced with viscous drag and gravitational force

• Study of dynamics of magnetic particles in the single alveolus during breathing in external magnetic field.
• Described physical model combining aerodynamic, gravitational and magnetic force exerted on magnetite microparticles as well as aerosol droplets containing SPIONs.
• Magnetic force on particles in studied source of magnetic field can overcome both, sedimentation and aerodynamic force during breathing, and induce their deposition in lung alveolus.
• Magnetically induced deposition in distal and proximal alveolus during rhythmical breathing is even possible for aerosol droplets with SPIONs.

Magnetic targeting of drugs attached to magnetic nanoparticles with diameter ≈100nm after their intravenous administration is an interesting method of drug delivery widely investigated both theoretically as well as experimentally. Our aim in this study is theoretical analysis of a magnetic aerosol targeting to the lung. Due to lung anatomy magnetic particles up to 5μm can be safely used, therefore the magnetic force would be stronger, moreover drag force exerted on the particle is according to Stokes law linearly dependent on the viscosity, would be weaker, because the viscosity of the air in the lung is approximately 200 fold smaller than viscosity of the blood. Lung therefore represents unique opportunity for magnetic drug targeting, as we have shown in this study by the analysis of magnetic particle dynamics in a rhythmically expanding and contracting distal and proximal alveolus subjected to high-gradient magnetic field generated by quadrupolar permanent Halbach magnet array.