A stepper micropump for ferrofluid driven microfluidic systems

We demonstrate a novel stepper micropump for ferrofluid driven microfluidic systems. The rotor is a ferrofluid plug that works as a piston pushing another liquid in a circular microchannel. The actuation concept is similar to that of a stepper motor, where the angular velocity can be precisely controlled by a series of actuating solenoids. The actuation force is adjusted by the driving voltage or current. Thus fluids with different viscosities can be handled in the pump. The pump can be used for a circular ferrofluid driven microchip for rapid polymerase chain reaction (PCR), where the sample is continuously pumped in a closed loop over three temperature zones to realize thermal cycling.