Low-dispersion electrokinetic flows for expanded separation channels in microfluidic systems:

Fiechtner, Gregory J.; Cummings, Eric B.

doi:10.1016/j.chroma.2003.08.050

Cited by 10 publications

(25 citation statements)

References 103 publications

(116 reference statements)

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“…Microfluidic devices with expansion microchannels are used for a variety of applications, including micromixers, microreactors, sample transportation, DNA analysis, and so on [37][38][39][40][41][42][43]. In the current study, experiments were conducted to investigate the EKI effects induced during the primary step of a pinched-flow electrokinetic injection process performed in cross-form expansion-channel microfluidic devices with various expansion ratios (D 2 /D 1 ) and sample stream/sheath flow conductivity ratios.…”

Section: Uncoated Cross-form Microfluidic Device With Expansion Confimentioning

confidence: 99%

“…Figure 2 presents a schematic illustration showing the basic steps in the fabrication procedure used to produce the current microfluidic devices [37][38][39][40]. The fabrication process commenced by annealing commercially available glass slides (76 Â 26 Â 1 mm 3 , Marienfeld, Germany) at a temperature of 4001C for 4 h in order to relieve any internal residual stresses.…”

Section: Micro-fabrication Processmentioning

confidence: 99%

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Electrokinetic instability effects in microchannels with and without nanofilm coatings

Hong

Wen

et al. 2008

Electrophoresis

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This paper presents a parametric experimental investigation into the electrokinetic instability (EKI) phenomenon within three different types of microfluidic device, namely T-type, cross-shaped, and cross-form with an expansion configuration. The critical electric field strength at which the EKI phenomenon is induced is examined as a function of the conductivity ratio, the microchannel width, the expansion ratio, and the surface treatment of the microchannel walls. It is found that the critical electric field strength associated with the onset of EKI is strongly dependent on the conductivity ratio of the two samples within the microfluidic device and reduces as the channel width increases. The surfaces of the microchannel walls are coated with hydrophilic or hydrophobic organic-based spin-on-glass (SOG) nanofilms for glass-based microchips. The experimental results indicate that no significant difference exists in the critical electric field strengths in the hydrophilic or hydrophobic SOG-coated microchannels, respectively. However, for a given conductivity ratio and microchannel width, the critical strength of the electric field is slightly lower in the SOG-coated microchannels than in the non-coated channels. In general, the results presented in this study demonstrate the potential for designing and controlling on-chip assays requiring the manipulation of samples with high conductivity gradients, and provide a useful general reference for avoiding EKI effects in capillary electrophoresis analysis applications.

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Section: Uncoated Cross-form Microfluidic Device With Expansion Confimentioning

confidence: 99%

Section: Micro-fabrication Processmentioning

confidence: 99%

Electrokinetic instability effects in microchannels with and without nanofilm coatings

Hong

Wen

et al. 2008

Electrophoresis

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“…A similar equation describes the motion of the interface along the outside of the turn. Equations (19)(20)(21)(22)(23)(24)(25)(26)(27) can be combined and integrated to obtain the interface position as a function of time. This simple analytical model yields significant insight into the development of the potential and the LB-TB interface motion.…”

Section: Simplified Analytical Model For Band Focusing Effectmentioning

confidence: 99%

“…We consider the solution of Eqs. (19)(20)(21)(22)(23)(24)(25)(26)(27) in a 1807 turn with R = 500 mm and w = 100 mm with a 10 V voltage drop in Fig. 4.…”

Section: Simplified Analytical Model For Band Focusing Effectmentioning

confidence: 99%

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Turn‐induced isotachophoretic focusing in microfluidic channels

Paschkewitz¹,

Molho²,

Xu³

et al. 2007

Electrophoresis

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Multifunctional microfluidic platforms that use ITP for sample stacking require the use of serpentine channels. When ITP is carried out in serpentine passages, the sample band shows dramatically different behavior than that observed in conventional on-chip CE. The band skew, defined as the distance between the leading and trailing edge of the band, is reduced and the sample is focused on the outside wall of the turn. This effect is explained using a simplified analytical model for the infinite Peclet number limit and the predicted trends are compared to full numerical simulations and experimental measurements. The outward focusing is driven by a wall-normal electric field that results from the skewed leading buffer-trailing buffer (LB-TB) interface. The results indicate that the degree of outward focusing is controlled by the ratio of the LB and TB conductivities, the ratio of the channel width to turn radius, and the Peclet number. Increasing the band skew, which shows a complex dependence on the nondimensional parameters, maximizes the outward focusing effect.

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Towards numerical prototyping of labs-on-chip: modeling for integrated microfluidic devices

Erickson

2005

Microfluid Nanofluid

151

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Low-dispersion electrokinetic flows for expanded separation channels in microfluidic systems:

Cited by 10 publications

References 103 publications

Electrokinetic instability effects in microchannels with and without nanofilm coatings

Electrokinetic instability effects in microchannels with and without nanofilm coatings

Turn‐induced isotachophoretic focusing in microfluidic channels

Towards numerical prototyping of labs-on-chip: modeling for integrated microfluidic devices

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