Pulsatile micromixing using water-head-driven microfluidic oscillators

Abstract

This study presents a pulsatile micromixer which does not use any dynamic off-chip controllers to achieve homogeneous mixing. The micromixer system consists of oscillator and mixer units that include microfluidic valves and elastomeric membranes. The oscillator unit autonomously generates pulsatile pressure using the constant input of water head pressure. Driven by the pulsatile pressure, periodic fluidic bands are generated in the mixer unit and are mixed within a short channel length. In this way, the oscillator unit controls fluidic switching frequency and the mixer unit regulates flow rate, separately. The mixing performance for various channel widths, switching frequencies, and flow rates is analyzed. The micromixer shows homogenous mixing with a mixing index of ∼90% for a flow rate of up to 20μL/min and switching frequency in the range of 14–20Hz.