Stagnation point control by pressure balancing in microchannel for high speed and high purity separation of microobject

Abstract

We developed a new system for random separation of a single microorganism, such as a living cell and a microbe, in a micro fluidic device under the microscope using laser manipulation and microchannel flow. The main flow in the microchannel splits at the exit of the sample chamber. One flow goes to the extraction port with high speed to take out the target. Another flow goes to the drain. The target was transported by laser manipulation from the sample chamber to put on the main flow. Since the force balance of the laser-trapped object is important for stable manipulation of the target, we propose the stagnation point control around the sample chamber exit. Pressure balance was adjusted and the stagnation point was controlled. Some preliminary experiments are conducted to show the effectiveness. The target was trapped by the laser transported to put on the main flow around the split area through the stagnation, and was taken out from the extraction port. Separation time was reduced less than 10 seconds.