Examination of Theoretical Models in External Voltage Control of Capillary Electrophoresis

Hartley, Nanette K.; Hayes, Mark A.

doi:10.1021/ac010816y

Cited by 15 publications

(13 citation statements)

References 45 publications

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“…Several other groups have demonstrated measurable flow control within microfluidic devices by using of 100-150 V/cm external electric field applied to closely-spaced multiple electrode architectures. [5][6][7][8][9] Although this technique is successful to electrophorese at low external voltages, it involves complex device architectures and instrumentation. To the best of our knowledge, no exploratory research has indicated the use of conducting separation matrices for low voltage capillary electrophoresis.…”

Section: Introductionmentioning

confidence: 99%

Low Voltage Capillary Electrophoresis Using High Conductivity Agarose Nano-Platinum Composites

Bhattacharya¹,

Gangopadhyay²,

Chanda³

et al. 2008

sens lett

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Micro-channel based electrophoretic separation systems are commonly used in gene sequencing and analysis. A significant amount of research has focused on the development of fast and high resolution separation systems as part of miniaturized genotyping platforms. These devices are not suitable for field deployment due to their high voltage requirements for micro-channel based electrophoresis. In order to address this issue, we have developed and tested a new agarose gel doped with nanoplatinum for conducting capillary electrophoresis in micro capillaries at low electric field values. The platinum nanoparticles reduce the gel resistance of the agarose gels by 3-4 fold. We have further observed a faster movement of DNA band in this novel gel material allowing a reduction of the fractionating electric field within Poly dimethyl Siloxane (PDMS) capillaries. Impedance studies performed on this new gel material indicate a 1.34 times increase in the dielectric constant of the medium as a result of doping by nano-particles and a 37% reduction in the resistance. We believe that the higher conductivity of the medium and an increased dielectric constant of the medium result in increased ionic mobility within this material. We have also compared the stain mobility values in glass PDMS capillaries of a 1 kbp ladder, and a 750 bp dS DNA segment and have successfully obtained electrophoresis within the micro-channels at a lower electric field (25 V/cm).

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Section: Introductionmentioning

confidence: 99%

Low Voltage Capillary Electrophoresis Using High Conductivity Agarose Nano-Platinum Composites

Bhattacharya¹,

Gangopadhyay²,

Chanda³

et al. 2008

sens lett

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“…The unpredictable EOF and strong wall adsorption of analyte may ruin the precision and limit the CE application in quantitative analysis. A number of methods have been developed for EOF control in a capillary, such as external electric field [14], physically adsorbed or covalent static coating [15], and dynamic coating [16]. Among them, the surfactant-based dynamic coating is a favorable method due to its versatility, stability, and facility.…”

Section: Introductionmentioning

confidence: 99%

Cationic gemini surfactant as dynamic coating in CE for the control of EOF and wall adsorption

Liu¹,

Li²,

Tang³

et al. 2007

Electrophoresis

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The cationic gemini surfactant ethylene bis(1-dodecyldimethylammonium) dibromide was used as a dynamic coating to control EOF and prevent wall adsorption of basic proteins in CE for the first time. This gemini surfactant shows a more powerful capability in EOF reversal than traditional single-chained surfactant. The gemini surfactant reverses the EOF at a concentration level even less than 0.01 mM, and the EOF magnitude is affected by surfactant concentration, pH, ionic strength, and ions added in buffer. Highly efficient and rapid protein separation (N > 300,000) was obtained with buffer containing 2 mM gemini surfactant under pH ranging from 3 to 6. The effects of surfactant and buffer concentration on protein separation were investigated in detail. Under the optimal conditions, good repeatability (RSD of migration time <0.6% for run-to-run and <2.5% for day-to-day assays) and recovery (>90%) of tested proteins were obtained. This new dynamic coating is also suitable for biosample analysis.

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“…Another means of controlling the EOF is by the application of an external electric field which forms a potential gradient with the usual internal electric field thereby creating a radial field; this adjustable gradient is perpendicular to the capillary wall and changes the density of electric charge on the inner capillary wall, thereby allowing for control of the EOF [19][20][21]. In addition to the EOF, all factors influencing the mobility would also need to be well controlled so as to maintain a constant m 0 since the desired EOF mobility depends upon this value.…”

Section: Discussionmentioning

confidence: 99%

A theoretical study of the possible use of electroosmotic flow to extend the read length of DNA sequencing by end‐labeled free solution electrophoresis

McCormick

Slater

2006

Electrophoresis

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End-labeled free solution electrophoresis (ELFSE) provides a means of separating DNA with free-solution CE, eliminating the need for gels and polymer solutions which increase the run time and can be difficult to load into a capillary. In free-solution electrophoresis, DNA is normally free-draining and all fragments reach the detector at the same time, whereas ELFSE uses an uncharged label molecule attached to each DNA fragment in order to render the electrophoretic mobility size-dependent. With ELFSE, however, the larger molecules are not separated enough (limiting the read length in the case of ssDNA sequencing) while the smaller ones are overseparated; the larger ones are too fast while the shorter ones are too slow, which is the opposite of traditional gel-based methods. In this article, we show how an EOF could be used to overcome these problems and extend the DNA sequencing read length of ELFSE. This counterflow would allow the larger, previously unresolved molecules more time to separate and thereby increase the read length. Through our theoretical investigation, we predict that an EOF mobility of approximately the same magnitude as that of unlabeled DNA would provide the best results for the regime where all molecules move in the same direction. Even better resolution would be possible for smaller values of EOF which allow different directions of migration; however, the migration times then would become too large. The flow would need to be well controlled since the gain in read length decreases as the magnitude of the counterflow increases; an EOF mobility double that of unlabeled DNA would no longer increase the read length, although ELFSE would still benefit from a reduction in migration time.

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Examination of Theoretical Models in External Voltage Control of Capillary Electrophoresis

Cited by 15 publications

References 45 publications

Low Voltage Capillary Electrophoresis Using High Conductivity Agarose Nano-Platinum Composites

Low Voltage Capillary Electrophoresis Using High Conductivity Agarose Nano-Platinum Composites

Cationic gemini surfactant as dynamic coating in CE for the control of EOF and wall adsorption

A theoretical study of the possible use of electroosmotic flow to extend the read length of DNA sequencing by end‐labeled free solution electrophoresis

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