Microchannels electrokinetic transport

Griffiths, S.K., Nilson, R.H., Modeling electrokinetic transport for the design and optimization of microchannel systems. Micro Total Analysis Systems, Proceedings 5th [lTAS Symposium, Monterey, CA, Oct. 21-25, 2001, 456 158. 

Almost at the same time, Ermakov et al. [3] presented a numerical model for electrokinetic transport in a simple cross-linked microchannel and a T-intersection microchannel. This model considered two sample species and was numerically solved using the finite difference method, where an intermediate velocity was introduced to generate an equation for the pressure and the continuity equation was used as a condition to ensure the mass conservation is satisfied. Sample focusing in the cross microchannel and sample mixing in the T-intersection channel were studied, and the effects of the electroosmotic mobility, electrophoretic mobihty, and apphed... 

Hu YD, Werner C, Li DQ (2003) Electrokinetic transport through rough microchannels. Anal Chem 75(21) 5747-5758... 

Tang GY, Yan DG, Yang C et al (2007) Joule heating and its effects on electrokinetic transport of solutes in rectangular microchannels. Sens Actuator A Phys 139 221-232... 

Li and Harrison carried out the first cell assay in microchannels [2]. This seminal work made use of electrokinetically driven flow (electroosmosis and electrophoresis) to transport bacteria, yeast, and mammalian cells in channels and to implement low-volume chemical lysis (cell death). This theme of microfluidics-based cell transport, sorting, and lysis has continued to be a popular application, as well as related work in using microfluidics to culture cells and to pattern them into structures. The utility of these methods is acknowledged (and that they are featured in several good reviews [1] and other entries in the encyclopedia) but focuses here on describing microfluidics-based cell assays that fit the definition described above - application of a stimulus and measurement of a response. 

Both the theoretical studies and the experimental studies have demonstrated that the loading and dispensing of sub-nanoliter samples using a microfluidic-crossing microchannel chip can be well controlled electrokinetically. The abiUty to inject and transport large axial extent. 

Electrokinetics is currently the preferred method for moving and transporting fluids in microchannels due to the ease of electrode fabrication and since electrokinetic mechanisms involve no moving mechanical parts which are... 

As the usual parabolic velocity profile of pressure-driven Poiseuille flow leads to the flow rate scaling as R whereas the flat velocity profile obtained in pure electroosmotic flow gives rise to a flow rate that scales as R, it can be seen that it is more efficient to drive microchannel flows where R becomes very small using electrokinetic flows as opposed to pressure-driven flow. However, there are some design issues to be considered in electrokinetic bubble transport. 

Comparable utilization of the tools of microfabrication for liquid-phase analyses came a decade later, when electrokinetic phenomena were proposed to separate dissolved species on chips the application of a high electric field between the ends of a smaU-diameter column or channel can both transport and separate dissolved species in conductive solution without moving mechanical parts. The concept of chip-CE (capillary electrophoresis) was first described in the patent literature in 1990, wherein CE separations are performed in microfabricated columns or microchannels on planar substrates. At the... 

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