Magnetic drug targeting by ferromagnetic microwires implanted within blood vessels

Purpose: The targeting of ferromagnetic drug carrier nanoparticles (DCNPs) by dilute microferro-magnetic wires implanted within blood vessels and subjected to an externally applied uniform magnetic field of 0.1-0.8 T was evaluated to determine their effectiveness in increasing the concentration of the DCNPs around the target wires. Methods: The transport of DCNPs under the influences of diffusion, blood convection, and magnetic force was simulated by solving the continuity equation using the finite difference method. Then the spatial distribution and time evolution of the particle concentration was determined. The effectiveness of implant-assisted magnetic drug targeting was evaluated from the average concentration of DCNPs around the representative target wire. Results: The average concentration of DCNPs of an average radius larger than 80 nm carried by blood flow with an average inlet flow rate of 1.1 cm s(-1) was increased to more than 60% of the injected concentration by using an externally applied magnetic field strength of 0.1 T. Conclusions: The effectiveness of concentrating DCNPs of an average radius not larger than 100 nm around the target wire within a small vein was significantly improved using an externally applied magnetic field strength of not greater than 0.8 T. (c) 2013 American Association of Physicists in Medicine.