Manipulation of flagellar driving force by local environmental control system with multiple nanoprobes

Micro/nano robots have been actively studied toward the realization. Now, the micro living organisms have been used as the driving forces for the micro objects. To achieve the fine manipulation of bio driven micro objects, the manipulation methods have to be established. Therefore, the local environmental control technique is desired to manipulate a single cell and to analyze the detailed properties. We have developed the local environmental control system with nano/micro dual pipettes, and achieved the quick-response and iterative rotational speed manipulation of Na⁺-driven flagellar motor, which is a rotary molecular machine, by switching the local spout between Na⁺-containing and Na⁺-free solutions with dual pipettes. In this paper, we upgrade our local environmental control system with nano/micro dual pipettes to achieve the quantitative and long-time-stable manipulation of the rotational speed of the Na⁺-driven flagellar motor. We demonstrate fine and long-time-stable rotational speed manipulation of Na⁺-driven flagellar motor by simultaneous local spouts of Na⁺-containing and Na⁺-free solutions using dual pipettes with controlling the spouting velocities independently. And, as the driving force, the rotational torque generated by the flagellar motor is estimated at the range from ~2.3×10³ to ~2.8×10³ pN·nm.