Bio-micropump by using a flagellate propulsive force of Escherichia coli

This paper has demonstrated that a novel bio-pump is realized using a propulsive bacterium, which is Escherichia coli, in PDMS microchannel. The propulsive force of E. coli is applied successfully to generate a pump pressure in the microchannel. E. coli is retained in a position by using double optical laser tweezers for driving surrounding fluids to backward using a propulsive force. The optical tweezers stabilize a bacterium body horizontally and vertically in the center of channel for keeping a propulsive direction hence the microchannel with a bacterium has a pump effect geometrically. The generated flow ratio in the microchannel is measured by tracking of tracer particles suspended in surrounding fluids. The bacterial pump pressure is estimated from the measuring flow rate according with the theoretical analysis. As results present bio-pump utilized more than 6 times bacterium propulsive force with the energy efficiency of about 0.2% by trapping their body horizontally. This is the first report on a bio-micropump with a more effective way to utilize bacteriological propulsion. This finding would be useful for a bio-inspired design of micro devices, especially a flagellate bio-micropump.