Development of local environmental control system by combination of microfluidic chip and pipette

Bio-actuated, especially flagellated bacteria-driven, micro/nanorobots have been actively studied to develop novel technologies such as drug delivery systems (DDS), though the characteristics of the actuator (flagellar motor) have not been sufficiently investigated. For analysis or control of the bacterial flagellar motor, we previously proposed the local environmental control system with nano/micro dual pipettes to dynamically generate arbitrary local ion/reagent concentration change. In the result, transient-state and steady-state of local Na⁺ concentration were manipulated with high facultativity. However, in this system, over time, the local ion/reagent could not be fully flushed out due to the increase of the diffusion rate caused by high external (in the bath) ion/reagent concentration. Therefore, in this paper, to achieve more arbitrary local environmental control, we propose the local environmental control system by combination of microfluidic chip with world-to-chip interface (WtCI) and pipette. We fabricate the WtCI microfluidic chip by two-step photolithography, and develop the system by using precisely controllable syringe pump. And, we demonstrate the basic feasibility of the local environmental control system by combination of WtCI microfluidic chip and pipette.