DNA separation by EFFF in a microchannel

Chen, Zhi; Chauhan, Anuj

doi:10.1016/j.jcis.2004.11.061

Cited by 30 publications

(27 citation statements)

References 41 publications

(51 reference statements)

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“…13) and the effective dispersion coefficient (Eq. 15), one may execute an analysis similar to that outlined in Chen and Chauhan [10] …”

Section: Calculation Of the Separation Efficiencymentioning

confidence: 99%

“…Particular attention is devoted to investigate these influences as a transitional behavior from microchannels to nanochannels. Following a method of regular perturbation analysis [10], detailed analytical expressions are derived for the dimensionless macromolecular band velocity and also for the dimensionless dispersion coefficient. Our attention is devoted to address the following queries: (i) how are the influences of transverse electromigrative mechanisms altered with the considerations of finite sizes of the separating species in nanoscopic confinements with strong EDL interactions, without necessarily incurring an EDL overlap and (ii) does any nontrivial effect exist with regard to the influences of macromolecular size disparities and the corresponding separation efficiencies in nanochannels?…”

Section: Introductionmentioning

confidence: 99%

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Electrokinetic separation of charged macromolecules in nanochannels within the continuum regime: Effects of wall interactions and hydrodynamic confinements

Das

Chakraborty

2008

Electrophoresis

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In this paper, a detailed continuum-based theoretical model is proposed to investigate the effects of near-wall potentials and hydrodynamic confinement on separation of charged macromolecules in channels of nanoscale dimensions. These wall effects are primarily confined within a few nanometers from the channel wall, and hence have negligible influences in the conventional electrokinetic separation methods that are routinely performed in microchannels. However, in nanochannels, their zone of influence becomes significant in comparison to the channel height, thereby inducing certain nontrivial effects on the resultant separation characteristics. By executing a regular perturbation analysis, it is established that depending on the macromolecular size relative to the channel height and the extent of electrical double layer (EDL) interactions, the wall forces decide the speed of traverse and the extent of spreading (dispersion) of the macromolecular bands. These factors combine together to finally decide the separation characteristics (quantified by the resolution of separation) of the charged macromolecules in nanochannels. It is demonstrated that because of the near-wall effects, macromolecular pairs with less disparities in sizes give rise to higher values of resolution. Moreover, the wall-induced influences are shown to magnify the resolution for any given pair of macromolecules in the nanofluidic systems, thereby signifying greater separation efficiency.

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“…13) and the effective dispersion coefficient (Eq. 15), one may execute an analysis similar to that outlined in Chen and Chauhan [10] …”

Section: Calculation Of the Separation Efficiencymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Electrokinetic separation of charged macromolecules in nanochannels within the continuum regime: Effects of wall interactions and hydrodynamic confinements

Das

Chakraborty

2008

Electrophoresis

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“…Figure 8 also shows that for small O, the curves exhibit a maximum at a value of PeR e that becomes small with increasing frequency. The origin of this maximum is described in detail by Chen and Chauhan [23].…”

Section: Dispersion Coefficientmentioning

confidence: 88%

Electrochemical response and separation in cyclic electric field‐flow fractionation

Chen

Chauhan

2007

Electrophoresis

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Electric field-flow fractionation (EFFF) is a separation technique that couples a lateral electric field with axial Poiseuille flow to separate particles on the basis of size and/or mobility. In unidirectional EFFF, the field rapidly decreases in time due to charging of the double layer. The field strength could be increased by performing EFFF with cyclic electric fields. In cyclic electric field-flow fractionation (CEFFF), a periodic voltage, which can be either sinusoidal or square-wave, is applied in the lateral direction. In this paper, we measure the electrochemical response of CEFFF, i.e., the current-time response for a given time-dependent voltage and then utilize this electrochemical response in a transport model to predict separation. The CEFFF device studied here comprises two gold-coated glass plates separated by a spacer. The transient current profiles are measured for a step change and cyclic square-shaped voltage. The current profile is compared with the equivalent circuit model, and is fitted to a sum of two decaying exponentials. The dependence of the electrochemical response on voltage, frequency, channel thickness, and salt concentration is studied. Next, the electrochemical data are utilized in the convection-diffusion equation to develop a model for separation by CEFFF. The equations are solved by using a combination of analytical and numerical techniques to determine the mean velocity and the dispersion coefficient of molecules, and to determine the effect of various parameters on the separation efficiency of the EFFF device. Also, the model predictions are compared with experimental data available in the literature.

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“…For particle retention in the channel, the node of a standing ultrasound wave should be formed near the channel wall, where slow streamlines occur. Equation (6) predicts that the node should be formed near the top of the channel at Δϕ = 90˚, and near the bottom of the channel at Δϕ = 260˚ under an ideal condition, as shown in the inset of Fig. 2.…”

Section: Effect Of a Phase Shift On Particle Retentionmentioning

confidence: 99%

“…[1][2][3][4][5][6] In this method, analytes distribute across the separation channel according to their hydrodynamic sizes and other physical properties, depending on the utilized field, and are then carried by an orthogonal laminar flow down to the outlet of the channel. The selection of a physical field is essential for the successful application of FFF; sedimentation, cross-flow, and electric fields are often employed in FFF.…”

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confidence: 99%

Microparticle Separation with an Acoustic-gravity Field Controlled by Phase-shift Operation

Masudo

Okada

2007

ANAL. SCI.

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The elution of particles from a coupled acoustic-gravity channel has been controlled by a phase-shift operation. Two ultrasound transducers pasted onto the top and bottom walls of a separation channel were driven at the same frequency, but with different phases. Changing the phases of the ultrasounds has allowed the formation of a node near the channel wall, and particles are retained in the channel. Two types of particles are separated under an appropriate condition.

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DNA separation by EFFF in a microchannel

Cited by 30 publications

References 41 publications

Electrokinetic separation of charged macromolecules in nanochannels within the continuum regime: Effects of wall interactions and hydrodynamic confinements

Electrokinetic separation of charged macromolecules in nanochannels within the continuum regime: Effects of wall interactions and hydrodynamic confinements

Electrochemical response and separation in cyclic electric field‐flow fractionation

Microparticle Separation with an Acoustic-gravity Field Controlled by Phase-shift Operation

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