Low-Voltage Electroosmosis Pump and Its Application to on-Chip Linear Stepping Pneumatic Pressure Source

Cheng

et al. 2009

Microfluid Nanofluid

302

202

Electroosmotic pumping is receiving increasing attention in recent years owing to the rapid development in micro total analytical systems. Compared with other micropumps, electroosmotic pumps (EOPs) offer a number of advantages such as creation of constant pulse-free flows and elimination of moving parts. The flow rates and pumping pressures of EOPs matches well with micro analysis systems. The common materials and fabrication technologies make it readily integrateable with lab-on-a-chip devices. This paper reviews the recent progress on EOP fabrications and applications in order to promote the awareness of EOPs to researchers interested in using micro-and nano-fluidic devices. The pros and cons of EOPs are also discussed, which helps these researchers in designing and constructing their micro platforms.

Section: Electroosmotic Pump Fabrications Techniquesmentioning

confidence: 99%

“…Figure 7 illustrates the working principle of a cascade open-channel EOP (Takamura et al 2001, 2003). A cascade open-channel EOP uses low voltages to generate large EOFs.…”

Section: Electroosmotic Pump Fabrications Techniquesmentioning

confidence: 99%

Electroosmotic pumps and their applications in microfluidic systems

Cheng

et al. 2009

Microfluid Nanofluid

302

202

“…Khandurina et al applied a porous silicate film as a salt bridge for electrophoresis . Takamura et al . and Brask et al developed a low-voltage cascade electroosmotic pump based on salt bridges.…”

mentioning

confidence: 99%

Cytometry and Velocimetry on a Microfluidic Chip Using Polyelectrolytic Salt Bridges

2005

This paper reports a polyelectrolytic salt bridge-based electrode (PSBE), which is a key embedded unit in a microchip device that can size-selectively count microparticles and measure their velocities. The construction of salt bridges at specific locations within a microfluidic chip enables dc-driven electrical detection to be performed successfully. This is expected to be a competitive alternative to the optical methods currently used in conventional cell sorters. The PSBEs were fabricated by irradiating ultraviolet light over a patterned mask on the parts of interest, which were filled with an aqueous monomer solution containing diallyldimethylammonium chloride. A pair of such PSBEs was easily formed at the two lateral branches perpendicular to the main microchannel and was found to be very useful for dc impedometry. The human blood cells as well as the fluorescent microbeads passing between the two PSBEs produced impedance signals in proportional to their size. The information about the velocity of a microparticle was extracted from a doublet of the dc impedance signals, which were generated when cells or microbeads sequentially passed through two PSBE pairs separated from each other by a fixed distance. The plot of peak amplitude versus velocity of the moving microbeads and cells indicated only a slight correlation between the size and the velocity, which means that the peak amplitude of the dc impedance signals alone can provide information about the size of the cells in a mixture. The experimental results showed a screening rate of over 1000 cells s(-1) and a velocity of the cells of over 100 mm s(-1). Compared with the previously suggested electrical detection system based on metal electrodes, the sensitivity and selectivity in cell detection were remarkably improved. In addition, the detection unit including the operating circuit became innovatively simple and the whole device could be miniaturized.

“…1, typically require the use of a high potential (sometimes > 1 kV) 4 and/or complex channel structures. 5,6 In previous research, Ajdari 7 had suggested that an ac electroosmosis flow (AC EOF) can be driven at a low ac potential without breaking the symmetrical electrode structures. Similarly, the pumping of fluid flow via asymmetric electrode arrays subjected to low-potential alternating electric fields had been reported with experimental demonstrations.…”

Section: Introductionmentioning

confidence: 99%

A novel microfluidic driver via AC electrokinetics

Kuo

Liu

2008

Lab Chip

A novel ac electrokinetic microfluidic driver based on alternating current electro-osmosis flow induced by asymmetrically capacitance/chemistry-modulated microelectrode arrays has been successfully developed and demonstrated. Asymmetric capacitance modulation (ACM) is made of comb electrode arrays and parts of individual electrode surfaces are modulated/deposited with a SiO(2) dielectric layer. This proposed design can be utilized to shift the optimal operation frequency of maximum velocity to a higher frequency to minimize electrolytic bubble generation and enhance micropumping performance. The pumping velocity, described in this paper, is measured via the tracing of microbeads and is a function of applied potential, signal frequency, buffer concentration, and dielectric layer thickness. A maximum pumping velocity up to 290 microm s(-1) in 5 mM buffer solution with the applied potential of 10 Vpp is observed in our prototype device, and the estimated maximum flow rate is up to 26.1 microl h(-1). This is the first successful demonstration regarding bubble-free ac electrokinetic micropumping via such asymmetrically capacitance-modulated electrode arrays. Design, simulation, microfabrication, experimental result, and theoretical model are described in this paper to characterize and exhibit the performance of the proposed novel bubble-free ac electrokinetic microfluidic driver.