A system for treating a fluid obstruction through remote physical manipulation of free magnetic nanoparticles introduced within vasculature of a subject, the system comprising: one or two motors (120, 324, 402, 442, 1240, 1245); a permanent magnet (102, 302, 436, 1205) having a magnetic field (618, 712, 812, 2450) and a directed magnetic gradient (814, 2480) that, in use, forms and controls magnetic rotors in a circulatory system; wherein the one or two motors (120, 324, 402, 442, 1240, 1245) are adapted to rotate the magnet (102, 302, 436, 1205); and a controller that, in use, causes the one or two motors (120, 324, 402, 442, 1240, 1245) (a) to control the position, rotation plane and rotation frequency of the magnetic field (618, 712, 812, 2450) of the magnet (102, 302, 436, 1205) to create a rotating and therefore time-varying magnetic field and (b) to control the direction of the magnetic gradient (814, 2480) of the magnet (102, 302, 436, 1205), wherein, in use, the controller positions and rotates the magnetic field (618, 712, 812, 2450) and directs the magnetic gradient (814, 2480) in a manner sufficient to cause magnetic nanoparticles introduced within vasculature to agglomerate into a plurality of magnetic nanoparticle rods (1525, 1805, 1806, 1807, 2030, 2055, 2122, 2275, 2310), wherein, in use, the time-varying magnetic field and the directed magnetic gradient cause the magnetic nanoparticle rods (1525, 1805, 1806, 1807, 2030, 2055, 2122, 2275, 2310) to generate flow patterns within a blood vessel (828, 1400, 1465, 2120, 2255, 2300, 2305, 2510, 2605, 2705, 2810, 2820) proximal to a fluid obstruction, wherein the flow patterns facilitate contact of a therapeutic agent introduced within the blood vessel (828, 1400, 1465, 2120, 2255, 2300, 2305, 2510, 2605, 2705, 2810, 2820) with the fluid obstruction. one or two motors (120, 324, 402, 442, 1240, 1245); a permanent magnet (102, 302, 436, 1205) having a magnetic field (618, 712, 812, 2450) and a directed magnetic gradient (814, 2480) that, in use, forms and controls magnetic rotors in a circulatory system; wherein the one or two motors (120, 324, 402, 442, 1240, 1245) are adapted to rotate the magnet (102, 302, 436, 1205); and a controller that, in use, causes the one or two motors (120, 324, 402, 442, 1240, 1245) (a) to control the position, rotation plane and rotation frequency of the magnetic field (618, 712, 812, 2450) of the magnet (102, 302, 436, 1205) to create a rotating and therefore time-varying magnetic field and (b) to control the direction of the magnetic gradient (814, 2480) of the magnet (102, 302, 436, 1205), wherein, in use, the controller positions and rotates the magnetic field (618, 712, 812, 2450) and directs the magnetic gradient (814, 2480) in a manner sufficient to cause magnetic nanoparticles introduced within vasculature to agglomerate into a plurality of magnetic nanoparticle rods (1525, 1805, 1806, 1807, 2030, 2055, 2122, 2275, 2310), wherein, in use, the time-varying magnetic field and the directed magnetic gradient cause the magnetic nanoparticle rods (1525, 1805, 1806, 1807, 2030, 2055, 2122, 2275, 2310) to generate flow patterns within a blood vessel (828, 1400, 1465, 2120, 2255, 2300, 2305, 2510, 2605, 2705, 2810, 2820) proximal to a fluid obstruction, wherein the flow patterns facilitate contact of a therapeutic agent introduced within the blood vessel (828, 1400, 1465, 2120, 2255, 2300, 2305, 2510, 2605, 2705, 2810, 2820) with the fluid obstruction.