A Soft Magnetic Core can Enhance Navigation Performance of Magnetic Nanoparticles in Targeted Drug Delivery

Magnetic nanoparticles (MNPs) are a promising candidate for use as carriers in drug delivery systems. A navigation system with real-time actuation and monitoring of MNPs is inevitably required for more precise targeting and diagnosis. In this paper, we propose a novel electromagnetic navigation system with a coil combined with a soft magnetic core. This system can be used for magnetic particle imaging (MPI) and electromagnetic actuator functions with a higher steering force and enhanced monitoring resolution. A soft magnetic core with coils can increase the magnetic gradient field. However, this also generates harmonic noise, which makes it difficult to acquire MNP monitoring signals with MPI. Therefore, the use of amplitude modulation magnetic particle imaging (AM MPI) is suggested. AM MPI uses a low-amplitude excitation field combined with a low-frequency drive field. Using this system, the measured signal becomes less sensitive to the soft magnetic core. Based on the new MPI scheme and the combination of the coil with the magnetic cores, the proposed navigation system can implement one-dimensional (1-D) MNP navigation and 2-D MPI. The proposed navigation system can shorten the 1-D guidance time by about 25% for MNPs in the size range of 45-60 nm and give an improved 2-D imaging resolution of 43%, compared with an air-coil structure.