A Magnetic Particle Imaging-Based Navigation Platform for Magnetic Nanoparticles Using Interactive Manipulation of a Virtual Field Free Point to Ensure Targeted Drug Delivery

Magnetic nanoparticles (MNPs) exhibiting certain superparamagnetic properties are optimal for drug delivery because they facilitate imaging and targeting of biological interactions at the cellular and molecular levels. In terms of monitoring, magnetic particle imaging (MPI) yields real-time MNPs position and concentration data, and guides MNPs to desired positions if an actuation function is available. Here, we describe a new, user-driven steering scheme for MNPs based on a virtual field free point (FFP). The scheme utilizes a general MPI system, with no need for additional hardware. The scheme facilitates interactive user manipulation with real-time imaging and MNPs actuation within the body. An FFP with four coils is used to model the resultant magnetic force and a virtual FFP to linearize that force with respect to the relative positions of the MNPs and the real FFP. Simulations and experiments confirm that the direction and magnitude of the forces exerted on MNPs via manipulation of the virtual FFP are controllable. An intuitive guidance system featuring real-time MPI at 2 Hz and user-driven virtual FFP manipulation (via a computer mouse) is employed to show that MNPs trajectories can be controlled. Our MPI-based navigation platform allows the user to effectively guide MNPs using real-time visual feedback, facilitating targeted drug delivery.