Miniaturized Electroosmotic Pump Capable of Generating Pressures of More than 1200 Bar

Abstract

The pressure output of a pump cannot be increased simply by connecting several of them in series. This barrier is eliminated with the micropump developed in this work. The pump is actually an assembly of a number of fundamental pump units connected in series. The maximum pressure output of this pump assembly is directly proportional to the number of serially connected pump units. Theoretically, one can always enhance the pressure output by adding more pump units in the assembly, but in reality the upper pressure is constrained by the microtees or microunions joining the pump components. With commercially available microtees and microunions, pressures of more than 1200 bar have been achieved. We have recently experimented using open capillaries to build this pump, but many capillaries have to be utilized in parallel to produce an adequate flow to drive HPLC separations. In this paper, we synthesize polymer monoliths inside 75 μm i.d. capillaries, use these monoliths to assemble miniaturized pumps, characterize the performance of these pumps, and employ these pumps for HPLC separations of intact proteins. By tuning the experimental parameters for monolith preparations, we obtain both negatively and positively charged submicrometer capillary channels conveniently. Each monolith in a 75 μm i.d. capillary is equivalent to several thousands of open capillaries.

Electroosmotic Flow Pump

“…Packed porous media EOF pumps [29][30][31][32], highly miniaturized and integrated microfluidic pumps, can drive high-pressure or flow-rate fluids. Similar to the porous membrane EOF pumps, the packed porous media EOF pumps have a large number of sub-micro-or nanopump channels inside.…”

“…Other noncontact microelectrodes, such as fused silica capillary microelectrodes [31,44], polyaniline-wrapped aminated graphene microelectrodes [45], and Ag/Ag2O microelectrodes [46], have been successfully fabricated to work as noncontact electrodes for bubble-free EOF pumps. In fabrication, three noncontact microelectrodes can be made from the chemical synthesis or assembly method in the laboratory.…”

“…The open capillary has the ability to deliver a wide range of sample reagents such as pure liquid drug reagents and aqueous solutions containing cells, particles, or biochemical macromolecules. The porous media EOF pumps [25][26][27][28][29][30][31][32] can also be used to drive pure liquid sample reagents for the injection purpose. For on-chip microfluidic delivery, open-channel EOF pumps [20][21][22][23][24] are the most popular pumping devices.…”

Induced charge electroosmosis micropumps using arrays of Janus micropillars

“…62 Several creative solutions have been developed to overcome these problems and enhance long-term pump stability. 56,58,63 Recently, new designs of electroosmotic pumps have continued to optimize designs for high flow rate or pressure 64 or low voltage. 59,65 Nonlinear electrokinetic flows represent an alternative solution; the capacitive AC current used to drive such flows alleviates Faradaic reactions.…”

Combining selection valve and mixing chamber for nanoflow gradient generation: Toward developing a liquid chromatography cartridge coupled with mass spectrometer for protein and peptide analysis

“…We have recently developed a high-pressure EOP [5e8] and incorporated it into a miniaturized HPLC system for protein and peptide separations [6,7,9,10]. Implementing a gradient elution using this EOP has been a challenge, because its pump rate becomes unstable when we use it to pump a highorganic-content solvent [9,10].…”