Rotational speed control of Na+-driven flagellar motor by local ion concentration changes with multiple nano/micro pipettes

Nano/micro robots have been actively studied toward the realization. Now, the micro living organisms are used as the driving forces for the micro objects. To achieve the fine control of bio driven micro objects, it is needed to establish the control method. Therefore, the local environmental control technique is desired to manipulate a single cell or to analyze the properties. We have constructed the local environmental control system with nano/micro dual pipettes, and achieved the quick-response and iterative rotational speed control of Na⁺-driven flagellar motor, which is a rotary molecular machine, by switching the local spout between Na⁺-containing and Na⁺-free solutions. In this paper, we upgrade our local environmental control system with nano/micro dual pipettes to achieve the quantitative and long-time-stable control of the rotational speed of the Na⁺-driven flagellar motor. We demonstrate fine and long-time-stable rotational speed control of Na⁺-driven flagellar motor by simultaneous local spouts of Na⁺-containing and Na⁺-free solutions with changing the spouting velocities independently.