Gravity-driven pulsatile micromixer without using dynamic off-chip controllers

This paper reports a pulsatile micromixer without using any dynamic off-chip controllers and only relies on constant water-head pressure. This significantly differs from other pulsatile micromixers that use expansive, bulky controllers including high-voltage power supplies and function generators. The device is composed of self-actuated oscillator and mixer units, both of which include microfluidic valves and flexible membranes, With a constant input of water-head pressure, the oscillator unit generates pulsatile pressure to drive the mixer unit, thereby producing narrow periodic fluidic bands of two solutions for rapid mixing. The micromixer achieves up to 95% mixing efficiency in the flow rate and flow switching frequency of 2-20 μL/min and 14-20 Hz, respectively.