Optimization of Field-Free Point Position, Gradient Field and Ferromagnetic Polymer Ratio for Enhanced Navigation of Magnetically Controlled Polymer-Based Microrobots in Blood Vessel

Microscale and nanoscale robots, frequently referred to as future cargo systems for targeted drug delivery, can effectively convert magnetic energy into locomotion. However, navigating and imaging them within a complex colloidal vascular system at a clinical scale is exigent. Hence, a more precise and enhanced hybrid control navigation and imaging system is necessary. Magnetic particle imaging (MPI) has been successfully applied to visualize the ensemble of superparamagnetic nanoparticles (MNPs) with high temporal sensitivity. MPI uses the concept of field-free point (FFP) mechanism in the principal magnetic field. The gradient magnetic field (| backward difference B|) of MPI scanners can generate sufficient magnetic force in MNPs; hence, it has been recently used to navigate nanosized particles and micron-sized swimmers. In this article, we present a simulation analysis of the optimized navigation of an ensemble of microsized polymer MNP-based drug carriers in blood vessels. Initially, an ideal two-dimensional FFP case is employed for the basic optimization of the FFP position to achieve efficient navigation. Thereafter, a nine-coil electromagnetic actuation simulation system is developed to generate and manipulate the FFP position and | backward difference B|. Under certain vessel and fluid conditions, the particle trajectories of different ferromagnetic polymer ratios and | backward difference B| were compared to optimize the FFP position.

Automated summary

Microscale and nanoscale robots, known as potential cargo systems for targeted drug delivery, can convert magnetic energy into locomotion effectively. Navigating and imaging these robots within a complex vascular system at a clinical scale is challenging, requiring a more precise hybrid control navigation and imaging system. Magnetic particle imaging (MPI) has been used to visualize superparamagnetic nanoparticles (MNPs) with high temporal sensitivity, using the field-free point (FFP) mechanism in the principal magnetic field and gradient magnetic field (| backward difference B|) of MPI scanners to navigate nanosized particles and micron-sized swimmers.