Ultrafast active mixer using polyelectrolytic ion extractor

Chun, Honggu; Kim, Hee Chan; Chung, Taek Dong

doi:10.1039/b715229a

Cited by 33 publications

(25 citation statements)

References 53 publications

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“…Chun et al employed ion bridges to make an ultrafast micromixer that operates by AC inputs (Chun et al 2008). Due to the AC current across a pair of ion bridges facing each other, ion depletion regions developed in the vicinity of the interfaces between the ion bridges and liquid phase alternatively shifted.…”

Section: Other Applicationsmentioning

confidence: 99%

Ion bridges in microfluidic systems

Park

Chung

Kim

2009

Microfluid Nanofluid

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Recently many microfluidic systems are increasingly equipped with functional units for ionic controls for various applications. In this review article, we define an ion bridge as a structure that controls current or distribution of ions in a microfluidic system, and summarize the ion bridges in the literature in terms of characteristics, fabrication methods, advantages and disadvantages. The ion bridges play two basic roles, namely to ensure electrical contact in a microfluidic network and mechanically separate a liquid phase from another. More interestingly, the charged surfaces of ion bridges, which can be chemically modified, create new characteristics such as permselectivity and concentration polarization. Asymmetric ion transport as well as ionic conductivity through the ion bridges suggests a variety of applications including sample preconcentration, electroosmotic pump, electrospray ionization, electrically driven valve and many others. This review categorizes the ion bridges into several classes and describes the structures, materials, fundamental functions and applications. In Perspectives, new opportunities of microfluidics and nanofluidics provided by the ion bridges are discussed.

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Section: Other Applicationsmentioning

confidence: 99%

Ion bridges in microfluidic systems

Park

Chung

Kim

2009

Microfluid Nanofluid

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“…This need is accentuated in microfluidic devices due to the low Reynolds number (Re 2 1) inhibiting mixing of heterogeneous flow streams. Thus, for example, assortment of methods (Nguyen and Wu 2005;Hessel et al 2005)-passive (Howell et al 2004) and active (Ahmed et al 2009;Bottausci et al 2007;Chun et al 2008)-have been proposed and have provided many advances in their application in microfluidics.…”

Section: Introductionmentioning

confidence: 98%

Micromixing via recirculatory flow generated by an oscillatory microplate

Lin

Liu

Lai

et al. 2011

Microfluid Nanofluid

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Mixing in micro-environment has been explored in a number of studies. This study presents a unique approach of efficient mixing of two heterogeneous streams via two counter-rotating recirculatory streams induced by in-plane resonance of a rectangular microplate actuated via Lorentz force. The generated time-mean flow structure was interrogated for mixing efficacy over a range of excitation voltage, Reynolds number, and Pèclet number, along with numerical analysis to probe the time-mean flow physics. Results show that the recirculatory flow is generated at the plate's edges due to local flow non-linearity, characteristic of acoustic streaming. The percentage of mixing, at one device length-scale downstream, attains 93% at a low Reynolds number of 0.0037 (based on mean velocity of 0.078 mm/s and channel height of 50 lm) at 8 V excitation. Further characterization via enhanced diffusivity shows a maximum of 80.7-fold increase. Comparison with other active mixers shows the current device achieves mixing in one of the shortest distances. The proposed approach is robust, tunable to attain desired mixing characteristics and essentially independent of the properties of the fluid medium, which should be useful in a number of microfluidic applications requiring fast mixing.

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“…When an electric field is applied across a pair of PGEs spaced the width of the microchannel apart, the counter ions of the polyelectrolytes carry the charge. This unique system has been utilized to implement cytometry and velocimetry in a microfluidic chip [14], and an effective micro-mixer has been constructed based on the ion depletion between PGEs [26]. The PGEs located between the microchannel and the electrode chamber prohibit not only direct contact between metal electrodes and diluted blood, but also aggregation of the blood cells or bubbles at the electrode surface.…”

Section: Introductionmentioning

confidence: 99%

Red blood cell quantification microfluidic chip using polyelectrolytic gel electrodes

Kim¹,

Chun²,

Kim³

et al. 2009

Electrophoresis

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This paper reports on a novel microfluidic chip with polyelectrolytic gel electrodes (PGEs) used to rapidly count the number of red blood cells (RBCs) in diluted whole blood. The proposed microdevice is based on the principle that the impedance across a microchannel between two PGEs varies sensitively as RBCs pass through it. The number and amplitude of impedance peaks provide the information about the number and size of RBCs, respectively. This system features a low-voltage dc detection method and non-contact condition between cells and metal electrodes. Major advantages include stable detection under varying cellular flow rate and position in the microchannel, little chance of cell damage due to high electric field gradient and no surface fouling of the metal electrodes. The performance of this PGEs-based system was evaluated in three steps. First, in order to observe the size-only dependence of the impedance signal, three different sizes of fluorescent microbeads (7.2, 10.0, and 15.0 mum; Bangs laboratories, USA) were used in the experiment. Second, the cell counting performance was evaluated by using 7.2 mum fluorescent microbeads, similar in size to RBCs, in various concentrations and comparing the results with an animal hematoanalyzer (MS 9-5; Melet schloesing laboratories, France). Finally, in human blood sample tests, intravenously collected whole blood was just diluted in a PBS without centrifuge or other pretreatments. The PGE-based system produced almost identical number of RBCs in over 800-fold diluted samples to the results from a commercialized human hematoanalyzer (HST-N402XE; Sysmex, Japan).

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Ultrafast active mixer using polyelectrolytic ion extractor

Cited by 33 publications

References 53 publications

Ion bridges in microfluidic systems

Ion bridges in microfluidic systems

Micromixing via recirculatory flow generated by an oscillatory microplate

Red blood cell quantification microfluidic chip using polyelectrolytic gel electrodes

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