A valveless micro impedance pump driven by electromagnetic actuation
Over the past two decades, a variety of micropumps have been explored for various applications in microfluidics such as control of pico- and nanoliter flows for drug delivery as well as chemical mixing and analysis. We present the fabrication and preliminary experimental studies of flow performance on the micro impedance pump, a previously unexplored method of pumping fluid on the microscale. The micro impedance pump was constructed of a simple thin-walled tube coupled at either end to glass capillary tubing and actuated electromagnetically. Through the cumulative effects of wave propagation and reflection originating from an excitation located asymmetrically along the length of the elastic tube, a pressure head can be established to drive flow. Flow rates were observed to be reversible and highly dependent on the profile of the excitation. Micro impedance pump flow studies were conducted in open and closed circuit flow configurations. Maximum flow rates of 16 ml min-1 have been achieved under closed loop flow conditions with an elastic tube diameter of 2 mm. Two size scales with channel diameters of 2 mm and 250 µm were also examined in open circuit flow, resulting in flow rates of 191 µl min-1 and 17 µl min-1, respectively.
© 2005 IOP Publishing Ltd. Received 25 October 2004, in final form 21 January 2005, Published 11 March 2005. We would like to give special thanks to the Gordon and Betty Moore Fellowship, Benjamin J. Rosen Fellowship, the Grubstake Fund and the Fehrer Fellowship for providing support for this project. Additionally, we would like to thank Professor Mladen Barbic for his advice on electromagnetic actuation as well as Apex Microtechnology for their generous contribution of electronic components.