Flow-through sampling for electrophoresis-based microfluidic chips using hydrodynamic pumping

Lin, Yi Hung; Lee, Gwo‐Bin; Li, Chun Wei; Huang, Guo‐Shing; Chen, Shu Hui

doi:10.1016/s0021-9673(01)01326-7

Cited by 58 publications

(48 citation statements)

References 16 publications

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“…The operation of the M6N EOF switching device differs from that of the 16N EOF device only in the increase in number of potential control points which are involved. Figure 2 illustrates the fabrication process [21][22][23][24][25][26][27][28] adopted in the present study. The microchips were fabricated upon substrates of commercially available polished soda lime glass of dimensions 4465061 mm 3 .…”

Section: Formulation and Numerical Methodsmentioning

confidence: 99%

Multiple injection techniques for microfluidic sample handling

Yang

Lee

et al. 2003

Electrophoresis

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This paper presents an experimental and numerical investigation into electrokinetic focusing flow injection for bioanalytical applications on 1 x N (i.e., 1 sample inlet port and N outlet ports) and M x N (i.e., M sample inlet ports and N outlet ports) microfluidic chips. A novel device is presented which integrates two important microfluidic phenomena, namely electrokinetic focusing and valveless flow switching within multiported microchannels. The study proposes a voltage control model which achieves electrokinetic focusing in a prefocusing sample injection system and which allows the volume of the sample to be controlled. Using the developed methods, the study shows how the sample may be prefocused electrokinetically into a narrow stream prior to being injected continuously into specified outlet ports. The microfluidic chips presented within this paper possess an exciting potential for use in a variety of techniques, including high-throughput chemical analysis, cell fusion, fraction collection, fast sample mixing, and many other applications within the micrototalanalysis systems field.

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Section: Formulation and Numerical Methodsmentioning

confidence: 99%

Multiple injection techniques for microfluidic sample handling

Yang

Lee

et al. 2003

Electrophoresis

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“…After the microchannels were formed, thermal fusion bonding and hydrofluoric acid (HF) bonding were used to seal the glass-based and quartz microfluidic channels, respectively. The fabrication process details for the glass-based and quartz chips can be found in the current authors' previous works [33,34].…”

Section: Microchip Preparationmentioning

confidence: 99%

On the surface modification of microchannels for microcapillary electrophoresis chips

et al. 2005

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This paper presents systematic investigation of the microchannel surface properties in microCE chips. Three popular materials for microCE chips, polydimethylsiloxane (PDMS), quartz, and glass, are used. The zeta potentials of these microchannels are calculated by measuring the EOF velocity to evaluate the surface properties after surface modification. The hydrophobic PDMS is usually plasma-treated for microCE applications. In this study, a new method using a high-throughput atmospheric plasma generator is adopted to treat the PDMS surface under atmospheric conditions. In this approach, the cost and time for surface treatment can be significantly reduced compared with the conventional vacuum plasma generator method. Experimental results indicate that new functional groups could be formed on the PDMS surface after treatment, resulting in a change in the surface property. The time-dependent surface property of the plasma-treated PDMS is then measured in terms of the zeta potential. Results show that the surface property will reach a stable condition after 1 h of plasma treatment. For glass CE chips, two new methods for changing the microchannel surface properties are developed. Instead of using complicated and time-consuming chemical silanization procedures for CE channel surface modification, two simple and reliable methods utilizing organic-based spin-on-glass and water-soluble acrylic resin are reported. The proposed method provides a fast batch process for controlling the surface properties of glass-based CE channels. The proposed methods are evaluated using PhiX-174 DNA maker separation. The experimental data show that the surface property is modified and separation efficiency greatly improved. In addition, the long-term stability of both coatings is verified in this study. The methods proposed in this study show potential as an excellent solution for glass-based microCE chip surface modification.

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“…The voltage switching scheme for flow-through sampling was similar to that described previously [1] with some modifications for electrospray. The inlet of the microchip was connected to a syringe pump (Series 74900; Cole Parmer Instrumental, Vernon Hills, IL, USA) and an injection valve with a 10 mL sampling loop using connecting capillaries (200 mm ID and 365 mm OD) for continuous sample loading [25]. For the analysis of protein samples, a digestion cartridge (25 mL) packed with trypsin-immobilized beads, an injection valve with a 25 mL sampling loop packed with Oligo R3 beads (Applied Biosystems, Foster City, CA, USA) were connected in series to the inlet of the microchip.…”

Section: Sample Processing Schemementioning

confidence: 99%

“…We previously demonstrated that the flow-through sampling could be coupled to the inlet of the glass microchip to achieve continuous hydrodynamic sampling via voltage gating [25]. Since the EOF generated on the modified PDMS microchip was relatively small compared to that generated by the glass chip, the feasibility of the fabricated PDMS microchip for flow-through sampling was examined by CCD taken near the cross region during sampling.…”

Section: Flow-through Samplingmentioning

confidence: 99%

Poly(dimethylsiloxane)‐based microfluidic device with electrospray ionization‐mass spectrometry interface for protein identification

Sung¹,

Huang²,

Liao³

et al. 2003

Electrophoresis

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An easy method to fabricate poly(dimethylsiloxane) (PDMS)-based microfluidic chips for protein identification by tandem mass spectrometry is presented. This microchip has typical electrophoretic microchannels, a flow-through sampling inlet, and a sheathless nanoelectrospray ionization (ESI) interface. The surface of the microchannel was modified with 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) and the generated electroosmotic flow under acidic buffer condition used for the separation was found to be more stable compared to that generated by the microchannel without modification. The feasibility of the device for flow-through sampling, separation, and ESI-MS/MS analysis was demonstrated by the analysis of a standard mixture composed of three tryptic peptides. Results show that four peaks corresponding to three peptide standards and acetylated products of the standard peptide were well resolved and the deduced sequences were consistent with those expected. Furthermore, the compatibility of this device with other miniaturized devices to integrate the whole process was also explored by connecting a miniaturized enzymatic digestion cartridge and a desalting cartridge in series to the sampling inlet of the microchip for the identification of a model protein, beta-casein.

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Flow-through sampling for electrophoresis-based microfluidic chips using hydrodynamic pumping

Cited by 58 publications

References 16 publications

Multiple injection techniques for microfluidic sample handling

Multiple injection techniques for microfluidic sample handling

On the surface modification of microchannels for microcapillary electrophoresis chips

Poly(dimethylsiloxane)‐based microfluidic device with electrospray ionization‐mass spectrometry interface for protein identification

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