A study on the development of a continuous peristaltic micropump using magnetic fluids

This paper presents the development of a peristaltic MF (magnetic fluid) micropump for the purpose of applications of ‘lab on a chip’, which is the core technology of the medical & biological fields.In the device, magnetic fluids are gathered in the round-shaped channel by the magnetic force, which is applied from the external permanent magnet controlled by stepping motor. The gathered MF lump deforms the silicone rubber diaphragm and then the deformed diaphragm pushes the sample liquid in the microchannel. The micropump was fabricated through the conventional MEMS (micromachining) technology. It doesn’t have any complicated moving part, but uses magnetic fluids as a driving source. Thus, the proposed micropump can realize more reliability and durability. In addition, the driving method of our ‘continuous peristaltic’ micropump is different from that of other pumps using cavity sequence. Consequently, it brings out significant improvements in the performance. Furthermore, it cannot only pump in forward and backward directions, but also can control flow rate by adjusting the external permanent magnet. The MF lump also serves as a valve when the stepping motor of micropump stands still. The maximum flow rate of the micropump was 2.8 μl/min at 4 rpm and 3.8 μl/min at 8 rpm.