Magnetic nanoparticles (MNPs) are effective drug carriers. By using electromagnetic actuated systems, MNPs can be controlled noninvasively in a vascular network for targeted drug delivery (TDD). Although drugs can reach their target location through capturing schemes of MNPs by permanent magnets, drugs delivered to non-target regions can affect healthy tissues and cause undesirable side effects. Real-time monitoring of MNPs can improve the targeting efficiency of TDD systems. In this paper, a two-dimensional (2D) real-time monitoring scheme has been developed for an MNP guidance system. Resovist particles 45 to 65 nm in diameter (5 nm core) can be monitored in real-time (update rate = 2 Hz) in 2D. The proposed 2D monitoring system allows dynamic tracking of MNPs during TDD and renders magnetic particle imaging-based navigation more feasible.

Magnetic nanoparticles (MNPs) are a promising candidate for carriers in drug delivery systems, and a navigation system with real-time actuation and monitoring of MNPs is inevitably required for more precise targeting and diagnosis. The major challenge for MNP navigation is achieving a high magnetic field gradient, which can provide a higher steering force with enhanced monitoring resolution. A soft magnetic core with coils can increase the magnetic gradient field; however, this also generates harmonic noise, which makes obtaining MNP monitoring signals with magnetic particle imaging (MPI) difficult. To allow both MPI and electromagnetic actuator functions with magnetic cores in real time, a novel navigation system with a coil-core structure for an MPI scheme is suggested, which is less sensitive to the core and has a higher magnetic steering force. Based on the new MPI scheme and soft magnetic cores, the proposed navigation system can implement one-dimensional MNP navigation and two-dimensional MPI with a higher steering force and enhanced image resolution.

The ability to focus spherical particles (SPPs) to a deep tumor region remains one of the major challenges in magnetic drug targeting (MDT). A number of studies have attempted to overcome this problem using fast magnetic pulses and ferromagnetic rods. However, focusing of the SPPs in the deep body organs remains unsolved using existing schemes. In this paper, we propose a novel electro-magnetic actuation scheme for pushing and focusing SPPs. The simulation results demonstrate that the newly proposed actuation scheme can focus SPPs to a target surface region, inside of a block filled with an environment that has the characteristics of blood. We then investigated the effects of the proposed focusing scheme in realistic blood vessels with a maximum length of about 10–12 cm. The results show that SPPs of 500 nm can be concentrated onto a target tumor region with up to 97.9% efficiency. The proposed electromagnetic actuation scheme can maximize the efficiency of MDT, while minimizing the side effects of drugs in other tissues.

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