Preliminary investigation of the feasibility of magnetic propulsion for future microdevices in blood vessels.

The Magnetic Resonance Submarine (MR-Sub) project is a first attempt to validate a new propulsion method for future small magnetically controlled microdevices suited for minimally invasive applications in blood vessels. A Magnetic Resonance Imaging (MRI) system provides the driving force in three dimensions to a ferromagnetic core that could be embedded onto a specialised microdevice. The paper describes preliminary tests made to match the magnetic force induced by an MRI system on a ferromagnetic sphere with the drag force it encompasses in a cylindrical tube. These tests provide a proof of concept demonstrating that this new method of propulsion is very promising within the constraints of such types of operations. This conclusion is based on specific measurements showing that 1010/1020 carbon steel spheres (3.175 mm and 2.381 mm in diameter) can withstand a maximum flow of 0.370 +/- 0.0064 l/min (19.5 cm/s) and 0.311 +/- 0.01209 l/min (16.4 cm/s) respectively when placed inside a 6.35 mm diameter PMMA tube and subjected to a 18 mT/m magnetic field gradient.