Spiral-type micro-machine for medical applications
K. Ishiyama;K. I. Arai;M. Sendoh;A. Yamazaki;
Spiral-type magnetic micro-machines, which are driven by a rotating magnetic field, are characterized by their wireless operation for swimming. The machines have to swim in a lower Reynolds number ( Re ) environment, when the machines are downsized, and work inside the human body. In this study, using various silicone oils whose kinematic viscosity ranged from 500 to 5 × 105 mm2/s, the swimming performance of the machine in an environment characterized by a low Reynolds number was examined. The machine, with a cylindrical NdFeB magnet as main component, could swim in the oils with Re = 10-7. This Reynolds number is same as that of a micro-machine with micron size swimming in the water. In addition, the machine could turn by controlling Neodymium Magnet the external rotational magnetic field, therefore the swimming direction of the machine could be controlled. Using these principles, a magnetic micro-machine, which can run in a gel, was also fabricated.
