Ionic liquid‐assisted PDMS microchannel modification for efficiently resolving fluorescent dye and protein adsorption

Xu, Yuanhong; Jiang, Hong; Wang, Erkang

doi:10.1002/elps.200700261

Cited by 38 publications

(28 citation statements)

References 55 publications

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“…The enantiomeric separation had a resolution greater than 1.7. In the other report, ionic liquids were also used for reducing adsorption on PDMS channel surfaces (5). Using a buffer that contained a mixture of ionic liquids and the nonionic surfactant Triton X-100, the resolution and efficiency of Cy3-labeled proteins was improved relative to previous reports.…”

Section: Technique Developments Separation Schemesmentioning

confidence: 99%

Capillary Electrophoresis in Bioanalysis

2008

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Science reports ∼4800 hits on capillary electrophoresis (CE) including 410 reviews. Because of the prominence of CE techniques in bioanalysis, we decided make them the focus of this review and selected 200 hundred papers representing advances in this field. The selected papers cover advances in CE theory, instrumentation, and methodologies that are specific to various analytes of biological origin or relevance. The group of analytes includes nucleic acids, proteins and peptides, carbohydrates, lipids, single cells, and bioparticles. In addition, we have included advances in the use of CE to define functional assays or to investigate biomolecular interactions. The use of microfabricated devices for CE analysis was not included because this is already covered in other review. Technique Developments Separation SchemesDetermining the velocity of the electroosmotic flow (EOF) and how it changes during an electrophoretic separation is still an important research topic. A simple method for EOF measurements using so-called thermal marks was reported (1). Here, a tungsten filament caused punctual heating at the capillary wall and caused a perturbation in the electrolyte concentration. A sequence of these "thermal marks" then migrated with the EOF until each mark reached and was detected by a conductivity detector. The feasibility of using thermal marks as internal EOF standards in different separation systems was thereby demonstrated.Isoelectric focusing separates amphoteric analytes such as proteins or peptides by the differences in their isoelectric points. Most of the reports on capillary isoelectric focusing (cIEF) describe an initial focusing phase after which the focused zones are mobilized and detected. A dynamic cIEF method for protein analysis was reported (2). This technique made it possible to control each protein's position and focused width by moving the pH gradient within the capillary through manipulation of the electric fields. An important advantage of this approach is the capability of collecting focused analytes from the central section, suggesting that there may be great potential for introducing selectively focused proteins to a second separation dimension such as LC or CE.Micellar electrokinetic capillary chromatography (MEKC) is typically incompatible with electrospray mass spectrometry (ESI-MS) because the nonvolatile surfactants in the micellar phase result in complicated adduct formation and loss of sensitivity during the electrospray process and because the presence of the organic solvent needed for electrospray may cause instability in the micellar phase. These drawbacks were overcome by using synthetic polymeric surfactants that can work as a pseudostationary phase and provide stable electrospray (3). The polymeric surfactant was made by polymerizing three amino acidderived (L-leucinol, L-isoleucinol, L-valinol) sulfated chiral surfactants. These polymeric

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Section: Technique Developments Separation Schemesmentioning

confidence: 99%

Capillary Electrophoresis in Bioanalysis

2008

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“…Functionalized ionic liquids are an emerging new material for both surface treatment 167 and separation medium functions.…”

Section: Ionic Liquidmentioning

confidence: 99%

Polymer sieving matrices in microanalytical electrophoresis

Chung

Kim

Herr

2014

Analyst

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Microfluidic design has advanced existing protein separation capabilities and supported novel assays. Key metrics for successful protein separations include fast, robust, and sensitive analysis of complex mixtures of bio-macromolecules. Attaining high separation resolution is a chief concern. Here we review recent advances in polymer-based electrophoresis sieving materials that are impacting microfluidic bioanalytical applications. Looking forward, we comment on unmet needs for advanced separation media in microto-nanoscale devices.

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“…Among them, PDMS, first introduced by Kumar and Whitesides [10] for the creation of micropatterned objects, has been widely employed [11,12]. Studies on solvent compatibility [13] and different possibilities for surface modification [14,15] are available. Moreover, it can be sealed to a wide variety of substrates.…”

Section: Introductionmentioning

confidence: 99%

Multiple‐point electrochemical detection for a dual‐channel hybrid PDMS‐glass microchip electrophoresis device

et al. 2009

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A new PDMS-based dual-channel MCE with multiple-point amperometric detection has been evaluated. Electrophoresis has been optimised in a single-channel device. Pretreatment with 0.1 M NaOH is very important for increasing and stabilising the EOF. The precision is adequate for a day's work in terms of both peak current and migration time. The RSD of the peak current for five successive signals was 1.9, 2.4 and 3.1% for dopamine, p-aminophenol and hydroquinone. RSD for the migration time was always less than 1.3%, which demonstrates the stability of the EOF and the possibility of running multiple experiments in the same microchip. The adequate inter-microchip precision as well as the rapid and simple manufacturing procedure indicates the disposable nature of the PDMS microchips. A dual-channel device with very simple multiple-point amperometric detection is proposed here. Elasticity of the PDMS allows removing the polymer slightly and aligning gold wires working electrodes. Injection can be performed from each of the sample reservoirs or from both simultaneously. The distance between the separation channels is critical for obtaining adequate signals as well as the introduction of a high-voltage electrode in the buffer reservoir. Simultaneous measurement of the same analytes in both channels is possible by applying the same potential. Moreover, since no cross-separation is produced, different analytes or samples can be simultaneously measured.

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Ionic liquid‐assisted PDMS microchannel modification for efficiently resolving fluorescent dye and protein adsorption

Cited by 38 publications

References 55 publications

Capillary Electrophoresis in Bioanalysis

Capillary Electrophoresis in Bioanalysis

Polymer sieving matrices in microanalytical electrophoresis

Multiple‐point electrochemical detection for a dual‐channel hybrid PDMS‐glass microchip electrophoresis device

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