Multiple Open-Channel Electroosmotic Pumping System for Microfluidic Sample Handling

Abstract

The development of a novel, fully integrated, miniaturized pumping system for generation of pressure-driven flow in microfluidic platforms is described. The micropump, based on electroosmotic pumping principles, has a multiple open-channel configuration consisting of hundreds of parallel, small-diameter microchannels. Specifically, pumps with microchannels of 1-6 microm in depth, 4-50 mm in length, and an overall area of a few square millimeters, were constructed. Flow rates of 10-400 nL/min were generated in electric-field-free regions in a stable, reproducible and controllable manner. In addition, eluent gradients were created by simultaneously using two pumps. Pressures up to 80 psi were produced with the present pump configurations. The pump can be easily interfaced with other operational elements of a micrototal analysis system (micro-TAS) device with multiplexing capabilities. A new microfluidic valving system was also briefly evaluated in conjunction with these pumps. The micropump was utilized to deliver peptide samples for electrospray ionization-mass spectrometric (ESI-MS) detection.

Electroosmotic flow in vapor deposited silicon dioxide and nitride microchannels

“…Another important microfluidic structure is the multichannel EOF pump. 4,6,20 This is shown as the upper channel in Fig. 1͑a͒.…”

“…Microfluidic systems find increasing application in areas such as microelectromechanical systems ͑MEMS͒ sensors [1][2][3] and actuators, [4][5][6] biological analysis, [7][8][9] and microelectronic cooling systems. 10,11 This article considers an electrical-based fluid driving force, electrokinesis ͑also known as electroosmosis͒, that can be applied to these systems.…”

Electroosmotic Flow Pump

“…These pumps can be described as direct open-channel EOF pumps [20][21][22][23][24], which are usually used to perform onchip integratable control of sample reagents in microfluidic chip systems. The open channels in these pumps are usually fabricated with photolithographic microfabrication technologies.…”

Study of an electroosmotic pump for liquid delivery and its application in capillary column liquid chromatography

“…The state of the art of the thermal pump is for interrupted operation rather than continuously pumping. The open-channel electroosmotic pumps (EOPs) are widely used in capillary electrophoresis and in lab-on-a-chip system, and a novel multiple open-channel electroosmotic pumping system for microfluidic sample handling has been reported recently by Lizar and Karger [15]. The disadvantages of the open-channel pump are the unstable flow rate and low pumping output pressure, in most cases lower than 100 cm hydraulic pressure.…”

“…Previous study showed that the flow rate of different solvents was not only dependent on the applied voltage and the characteristics of EOP, but also dependent upon the properties of the solvent [9][10][11][12][13][14][15][16]. It had never been approved by experiment about the possible molecular discrimination effect of an EOP for a mixture of organic solvents or a water-organic solvent mixture commonly used in reversed-phase HPLC.…”