Flow Batteries for Microfluidic Networks: Configuring An Electroosmotic Pump for Nonterminal Positions

摘要

ABSTRACT: A micropump provides flow and pressure for a lab-on-chipndevice, just as a battery supplies current and voltage for an electronicnsystem. Numerous micropumps have been developed, but none is asnversatile as a battery. One cannot easily insert a micropump into annonterminal position of a fluidic line without affecting the rest of thenfluidic system, and one cannot simply connect severalmicropumps in seriesnto enhance the pressure output, etc. In this work we develop a flow batteryn(or pressure power supply) to address this issue. A flow battery consists of anþEOP (in which the liquid flows in the same direction as the field gradient)nand a -EOP (in which the liquid flows opposite to the electric fieldngradient), and the outlet of the þEOP is directly connected to the inlet of the -EOP. An external high voltage is applied to thisnoutlet-inlet joint via a short gel-filled capillary that allows ions but not bulk liquid flow, while the þEOP’s inlet and the -EOP’snoutlet (the flow battery’s inlet and outlet) are grounded. This flow battery can be deployed anywhere in a fluidic network withoutnelectrically affecting the rest of the system. Several flow batteries can be connected in series to enhance the pressure output to drivenHPLC separations. In a fluidic system powered by flow batteries, a hydraulic equivalent of Ohm’s law can be applied to analyzensystem pressures and flow rates.