Fine Positioning of Micro-Tubular-Tools for Investigating the Stimulus Response of Swimming Paramecium

We propose a new driving method for actuating micro-tubular-tool inside the fluidic environment to apply local stimulation to a freely swimming Paramecium. The hydrodynamic drag force acting on the very thin tool is significant and the resultant deflection was compensated by utilizing permanent magnets. The positioning accuracy of the microtools were enhanced more than ten times compared to normal actuation without magnets. The microtools can be integrated as robotic arms in a robotic platform that can track a single motile cell inside a microfluidic chip for a long-time. The specific design of the stimulation system using microtools was described and the effectiveness of the new driving method was confirmed through the basic experiments. Finally, the microtools were used to apply mechanical and electrical stimulation to a freely swimming Paramecium. The microtools can be used to achieve simultaneous multi-stimulation which can induce new behaviors of the motile cells and lead for unprecedented discoveries in biological fields.