Magnetic navigation and tracking of multiple ferromagnetic microrobots inside an arterial phantom setup for MRI guided drug therapy

Magnetic steering of ferromagnetic microrobots facilitates active drug targeting and minimally invasive treatment of deep seated tumour cells. Several techniques for magnetic steering of nanostructured single microrobot in human vasculature exist but literatures on multirobot navigation are scarce. In the current work, preliminary experimental validation of a novel magnetic navigation model for multiple ferromagnetic microrobots is performed inside a bifurcated arterial phantom apparatus. The proposed model includes the formation of a single linear assembly of ferromagnetic microrobots inside the arterial setup placed under a magnetic field. This field is intended to mimic the magnetic field generated by a Magnetic Resonance Imaging (MRI) device which finds application in targeted drug therapy. The linear assembly process was studied with the help of Newtonian dynamics simulation including dipole-dipole and near field forces. As, the assembly was found to be structurally intact in a pulsatile flow, its simulated trajectory was controlled by manipulating a single microrobot present in the middle of the assembly. The trajectory convergence algorithm used for this purpose includes a fuzzy logic based nonlinear “Proportional-Integral-Derivative” (PID) control scheme with magnetic field gradient as its control input. Since most of the modern MRI devices are based on PID controller for manipulation of magnetic gradients, the proposed fuzzy PID based control scheme can easily be interfaced with these devices for the intended application.