Electroosmotically Induced Hydraulic Pumping on Microchips: Differential Ion Transport

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• 作者：Christopher T. Culbertson ; Roswitha S. Ramsey ; and J. Michael Ramsey
• 刊名：Analytical Chemistry
• 出版年：2000
• 出版时间：May 15, 2000
• 年：2000
• 卷：72
• 期：10
• 页码：2285 - 2291
• 全文大小：207K
• 年卷期：v.72,no.10(May 15, 2000)
• ISSN：1520-6882

文摘

The theory behind and operation of an electroosmoticallyinduced hydraulic pump for microfluidic devices is reported. This microchip functional element consists of atee intersection with one inlet channel and two outletchannels. The inlet channel is maintained at high voltagewhile one outlet channel is kept at ground and the otherchannel has no electric potential applied. A pressure-induced flow of buffer is created in both outlet channelsof the tee by reducing electroosmosis in the groundchannel relative to that of the inlet channel. Spatiallyselective reduction of electroosmosis is accomplished bycoating the walls of the ground channel with a viscouspolymer. The pump is shown to differentially transportions down the two outlet channels. This ion discriminationability of the pump is examined as a function of ananalyte's electrophoretic velocity. In addition, we demonstrate that an anion can be rejected from the groundchannel and made to flow only into the field-free channelif the electrophoretic velocity of the anion is greater thanthe pressure-generated flow in the ground channel. Thevelocity threshold at which anion rejection occurs can beselectively tuned by changing the flow resistance in thefield-free channel relative to the ground channel.