Elastomer-glass micropump employing active throttles

Abstract

We report a reciprocating microfluidic pump, the Micro Throttle Pump (MTP), constructed in a relatively uncomplicated manner from glass and microstructured poly(dimethylsiloxane) (PDMS). Unconventionally, the MTP employs throttling of fluid flow as distinct from fully-closing valve structures. Accordingly, this technique offers the prospect of solid-phase suspension tolerance. The reported MTP employs piezoelectrically (PZT) actuated deformation of flow constrictions (throttles) fabricated from PDMS at the two ports of a central, PZT actuated pump chamber. By appropriate time-sequencing of the individual PZTs' actuation, pumping can be induced in either direction. PDMS' elasticity further facilitates throttle operation by virtue of allowing significant PZT flexure that is substantially independent of the underlying PDMS microstructure. In contrast, in a rigid substrate such as silicon, deformation is constrained to where underlying microstructured cavities exist and this restricts design options. We describe the construction and performance of a prototype MTP capable of pumping 300 µl min⁻¹ or alternatively generating a back-pressure of 5.5 kPa. Preliminary modelling of MTP operation is also presented.