Search

Magnetic targeted-drug delivery system (MTDs) works as a promising cancer treatment approach, and is entering the mainstream. It applies an external magnetic field to attract and guide the magnetic nanoparticles (MNPs) carrying treatment agent and targeted antibodies to the lesion region. Its key factor is the high gradient magnet. Here three types of magnets are proposed, i.e., open circuit magnet, close circuit magnet with planar poles, and close circuit magnet with concave-convex poles. And then their magnet field distributions are calculated through the finite element method (FEM). The simulation results are compared with each other and the measurement of Gauss Meter for the manufactured magnet, and the primary experimental result is also reported. It is found the closed magnet circuit with concave-convex poles shows about 2.0 and 1.2 times higher magnetic field intensity (H) than the open magnet circuit and the close magnet circuit with planar poles, respectively. Most important is it owns largest Grad (H) (1.0 e6 A/m2) among three magnets. The simulation agrees well with the measurement, and the primary experimental results also show the magnet can attract MNPs efficiently. Hence the calculation enables provide with credible input for the further trajectory simulation for MNPs.

Magnetic nanoparticles (MNPs) have been considered as potential therapeutic agent carrier for the magnetic targeted-drug delivery in the fight against cancer. Trajectories of MNPs in the blood vessel determine the capture and retention ratio, and the final effectiveness of the treatment. In the present study, a theoretical model of MNPs trajectory is deduced at first. Then two kinds of magnets are proposed, and their magnetic field distributions are calculated through the finite element method software of ANSYS. Using the model and magnetic field inputs, the MNPs trajectories are determined, and the influences of the MNP diameter (Rp), the blood flow velocity (vf) and magnetic field intensity (H) on the trajectories are clarified finally. It is found that the proposed method combining the theoretical model and numerical simulation is feasible. The closed magnetic circuit with concave-convex poles has better MNPs retention ratio than that of the open magnetic circuit because it has higher H and Grad (H). LargeRp, lowvf, and high H are good to capture the MNPs. Especiallyvfand H are critical parameters for the retention ratio of MNPs, and highvfand low H may let MNPs escape the magnetic field region.