An active flow focusing microfluidic chip utilizing controllable moving walls for the formation of micro-droplets in liquids

We have demonstrated a new microfluidic device for active sample flow focusing and the formation of micro-scale droplets in liquids application utilizing a novel controllable moving wall structure. The integration of two microfluidic components including the active microchannel width controller and micro chopper devices onto the chip device could be used to obtain the active flow focusing effect of the sample flow and micro-droplets formation. Three pneumatic side-chambers were placed next to the micro sample flow channel to construct the controllable moving wall structure, and the deformation of the moving wall structure can be used to control the sample stream width and cut the focused sample flow into micro-droplets. Experimental data show that the sample flow could be focused into smaller width and well-controlled micro-droplets with smaller diameter could be generated by utilizing low air pressure.