Highly efficient dynamic modification of plastic microfluidic devices using proteins in microchip capillary electrophoresis

Naruishi, Nahoko; Tanaka, Yoshihide; Higashi, Tetsuji; Wakida, Shin‐ichi

doi:10.1016/j.chroma.2006.07.005

Cited by 17 publications

(12 citation statements)

References 28 publications

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“…Little work has been done on measuring EOF mobility and understanding the surface chemistry of PMMA coated with surfactants. Even though surface modification by polymers and surfactants have been investigated in PMMA microchips , a detailed explanation on the effect of surfactant on EOF at different concentrations has not been presented. Moreover, to the best of our knowledge, the effect of mixed surfactants (ionic/nonionic) or a surfactant and a neutral polymer on EOF has not been reported yet.…”

Section: Introductionmentioning

confidence: 99%

Surfactant‐induced electroosmotic flow in microfluidic capillaries

Azadi¹,

Tripathi

2012

Electrophoresis

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Control of EOF in microfluidic devices is essential in applications such as protein/DNA sizing and high-throughput drug screening. With the growing popularity of poly(methyl methacrylate) (PMMA) as the substrate for polymeric-based microfludics, it is important to understand the effect of surfactants on EOF in these devices. In this article, we present an extensive investigation exploring changes in EOF rate induced by SDS, polyoxyethylene lauryl ether (Brij35) and CTAB in PMMA microfluidic capillaries. In a standard protein buffer (Tris-Glycine), PMMA capillaries exhibited a cathodic EOF with measured mobility of 1.54 ± 0.1 (× 10⁻⁴ cm²/V.s). In the presence of surfactant below a critical concentration, EOF was independent of surfactant concentration. At high concentrations of surfactants, the electroosmotic mobility was found to linearly increase/decrease as the logarithm of concentration before reaching a constant value. With SDS, the EOF increased by 257% (compared to buffer), while it was decreased by 238% with CTAB. In the case of Brij35, the electroosmotic mobility was reduced by 70%. In a binary surfactant system of SDS/CTAB and SDS/Brij35, addition of oppositely charged CTAB reduced the SDS-induced EOF more effectively compared to nonionic Brij35. We propose possible mechanisms that explain the observed changes in EOF and zeta potential values. Use of neutral polymer coatings in combination with SDS resulted in 50% reduction in the electroosmotic mobility with 0.1% hydroxypropyl methyl cellulose (HPMC), while including 2% poly (N,N-dimethylacrylamide) (PDMA) had no effect. These results will potentially contribute to the development of PMMA-based microfluidic devices.

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Section: Introductionmentioning

confidence: 99%

Surfactant‐induced electroosmotic flow in microfluidic capillaries

Azadi¹,

Tripathi

2012

Electrophoresis

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“…However, little attention has been devoted to examining the reproducibility of the performance of fabricated plastic chips using a dynamic coating [23,24]. In a benchmark paper on numerous plastic materials for hot-embossed CE microchips, Soper et al demonstrated that several physicochemical properties and the associated operational performance must be considered to obtain reproducible electrophoretic separations [21].…”

Section: Introductionmentioning

confidence: 99%

Characterization and performance of injection molded poly(methylmethacrylate) microchips for capillary electrophoresis

Nikčević

Lee

Piruska

et al. 2007

Journal of Chromatography A

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Injection molded poly(methylmethacrylate) (IM-PMMA), chips were evaluated as potential candidates for capillary electrophoresis disposable chip applications. Mass production and usage of plastic microchips depends on chip-to-chip reproducibility and on analysis accuracy. Several important properties of IM-PMMA chips were considered: fabrication quality evaluated by environmental scanning electron microscope imaging, surface quality measurements, selected thermal/electrical properties as indicated by measurement of the current versus applied voltage (I-V) characteristic, and the influence of channel surface treatments. Electroosmotic flow was also evaluated for untreated and O 2 reactive ion etching (RIE) treated surface microchips. The performance characteristics of single lane plastic microchip capillary electrophoresis (MCE) separations were evaluated using a mixture of two dyes -fluorescein (FL) and fluorescein isothiocyanate (FITC). To overcome non-wettability of the native IM-PMMA surface, a modifier, polyethylene oxide was added to the buffer as a dynamic coating. Chip performance reproducibility was studied for chips with and without surface modification via the process of RIE with O 2 and by varying the hole position for the reservoir in the cover plate or on the pattern side of the chip. Additionally, the importance of reconditioning steps to achieve optimal performance reproducibility was also examined. It was found that more reproducible quantitative results were obtained when normalized values of migration time, peak area and peak height of FL and FITC were used instead of actual measured parameters

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“…To do so, 40 mg/mL lysozyme in PBS buffer [38] was flushed through the affinity monolith at 2 µL/min for 20 min after antibody immobilization. Then the affinity column was rinsed with deionized water at 5 µL/min for 10 min to wash out any unbound lysozyme.…”

Section: Methodsmentioning

confidence: 99%

Affinity monolith preconcentrators for polymer microchip capillary electrophoresis

2008

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Developments in biology are increasing demands for rapid, inexpensive, and sensitive biomolecular analysis. In this study, polymer microdevices with monolithic columns and electrophoretic channels were used for biological separations. Glycidyl methacrylate-co-ethylene dimethacrylate monolithic columns were formed within poly(methyl methacrylate) microchannels by in situ photopolymerization. Flow experiments in these columns demonstrated retention and then elution of amino acids under conditions optimized for sample preconcentration. To enhance analyte selectivity, antibodies were immobilized on monoliths, and subsequent lysozyme treatment blocked nonspecific adsorption. The enrichment capability and selectivity of these affinity monoliths were evaluated by purifying fluorescently tagged amino acids from a mixture containing green fluorescent protein (GFP). Twenty-fold enrichment and 91% recovery were achieved for the labeled amino acids, with a <25,000-fold reduction in GFP concentration, as indicated by microchip electrophoresis analysis. These devices should provide a simple, inexpensive, and effective platform for trace analysis in complex biological samples.

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Highly efficient dynamic modification of plastic microfluidic devices using proteins in microchip capillary electrophoresis

Cited by 17 publications

References 28 publications

Surfactant‐induced electroosmotic flow in microfluidic capillaries

Surfactant‐induced electroosmotic flow in microfluidic capillaries

Characterization and performance of injection molded poly(methylmethacrylate) microchips for capillary electrophoresis

Affinity monolith preconcentrators for polymer microchip capillary electrophoresis

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