Control of Osmotic-Engine-Driven Liposomes Using Biological Nanopores

Liposome-based molecular robots that molecular systems are integrated into a giant liposome have been proposed; they are expected to be applied in the fields of medicine, environmental science, food science, and energy science. However, the performance of these molecular robotic components, including intelligence, sensors, and actuators, still hinders their practical use. In particular, the actuators used in the molecular robots, such as molecular motors, do not provide sufficient performance to move the giant liposomes. Hence, we propose an osmotic-engine-driven liposome and demonstrate the migration of liposomes in a microfluidic channel by applying a salt concentration difference between the front and rear of the liposome. Although the migration mechanism is simple and has the potential to provide sufficient mobility performance, control techniques for the movement speed and on/off switching are not established. Herein, we describe a speed control method of osmotic-engine-driven liposomes using pore-forming membrane proteins. In this study, we evaluated the effect of reconstituted α-hemolysin (αHL) nanopores on the water permeability through lipid bilayers. Thereafter, we demonstrated the change in displacement speeds of liposomes with and without nanopores. We expect the speed control method using nanopores to be applied to the liposome-based molecular robots.