Design of microfluidic impellers capable of bi-directional pumping under a single rotating magnetic actuation

In this paper, we advance our previous dynamic microfluidic micropumps by designing and developing nickel (Ni) impellers that pump and recirculate fluid in both forward and reverse directions, while being driven by a single external rotating magnetic stirrer rotating in the same direction. Liquid-phase photopolymerization and Ni electroforming are leveraged and integrated together to fabricate polymerbased micropumps with different Ni impeller geometries. Experiments were conducted to determine the effect of magnetic stirrer frequency on the average flowrate achieved by the different Ni impeller geometries. The forces that dictate the direction of the fluid flow is also discussed.