Dr. Sylvain Martel explains at the last issue of the Spectrum (the journal of the Institute of Electrica nd Electronic Engineers) the research his team is doing at the École Polytechnique de Montréal.
The article describes how they use an MRI machine for robotic navigation. Using the extremely high and uniform field, they strongly magnetize the bead. As the field is uniform, the bead doesn’t move. Then, the gradient coils are activated and the bead pushed forward. By changing the direction of the gradient field, the bead moves through the artery.
The group of Dr. Martel plans to use as microbot the MC-1, a 2 µm diameter magnetotactic bacteria with a chain of iron oxide nanocrystals (magnetosomes). They can attach the drugs to the surface and, as the magnetic charge is big enough, use electromagnetic coils for orienting the magneic field by varying the current. The magnetostatic bacteria then navigates the twists and turns of the vascular network.
An online version of the article, with the title “Magnetic Microbots to Fight Cancer” can be found at the spectrum site http://spectrum.ieee.org/robotics/medical-robots/magnetic-microbots-to-fight-cancer