Analysis and Design of a New Hybrid Array for Magnetic Drug Targeting

Magnetic drug targeting (MDT) is a method of remotely targeting drugs containing magnetic vehicles to the target area in the body through an external magnetic field. With a series of advantages of improving efficacy and reducing or eliminating the adverse effects, MDT shows great potential in clinical applications. The process of delivering magnetic drug particles by the magnetic field can be summarized into two steps. First, a static magnetic field is used to attract magnetic drug particles. Second, magnetic drug particles are delivered to accurately focus on the lesion site by changing the magnetic field. A number of studies have attempted to achieve the goals using permanent magnets (PMs) or electromagnets. For approaches using PMs, a mechanical system is necessary to realize the movement of PMs to obtain a changing magnetic field, which is usually inconvenient and difficult to operate. For electromagnets, generally a lot of energy is required to continuously generate a static magnetic field. In this study, a new hybrid array structure composed of PMs and electromagnets is introduced. The PMs in this array are mainly responsible for obtaining a continuous static magnetic field to attract magnetic drug particles; the changing magnetic field by electromagnets is used to deliver magnetic drug particles. The proposed hybrid array design has a simple structure, which is convenient to consume less energy. Methodologically, the design of the new hybrid array uses the methods of separating variables and charge models to calculate the magnetic field and magnetic force. Moreover, the results of the calculation and finite-element method (FEM) are compared with the measured values, which show good consistency. Finally, we investigated the change of the magnetic field above the array and the floating force. The results demonstrate that the new hybrid array can generate a variable magnetic field to concentrate magnetic drug particles to a specific location.