Control of Flow Direction in Microfluidic Devices with Polyelectrolyte Multilayers

Barker, Susan L. R.; Ross, David; Tarlov, Michael J.; Gaitan, Michael; Locascio, Laurie E.

doi:10.1021/ac0008690

Cited by 185 publications

(164 citation statements)

References 18 publications

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“…To stabilize the EOF, it has been proposed to control the pH of the eluent, or to fix the zeta potential of the capillary either by chemical modification or by adsorption. In the latter case, adsorption of polyelectrolytes is rather an easy route to achieve this goal [6][7][8][9][10]. Except for modulating the EOF, these adsorption methods, both covalent and noncovalent, have also been used to prevent nonspecific adsorption, or as a means to attach active molecules (such as antibodies) to the surface.…”

Section: Introductionmentioning

confidence: 99%

Polyelectrolyte‐modified short microchannel for cation separation

2004

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Three alkali cations, potassium, sodium, and lithium, have been separated within 15 s in a 1 cm long polymer microchip. The separation microchannel is modified by a polycation, poly(allylammonium chloride), which makes the channel surfaces positively charged leading to a reversed electroosmotic flow (EOF) when compared to bare channels. Due to the decreased apparent mobility of the cations, the separation resolution is improved allowing the use of shorter channels.

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Section: Introductionmentioning

confidence: 99%

Polyelectrolyte‐modified short microchannel for cation separation

2004

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“…Kenis et al demonstrated inchannel surface patterning as small as 5 m using selective etching, surface reactions, and precipitation controlled by "fabrication using laminar flow", which the authors called FLO. 53 The FLO method is suitable for a wide range of chemical treatments, including polyelectrolyte adsorption, 54,55 various organic SAMs, 26 and inorganics. 33 Zhao et al used streams of octadecyltrichlorosilane ͑OTS͒ in an organic solvent and OTS-free streams to pattern glass microchannels with hydrophobic stripes, as shown in Fig.…”

Section: A Laminar Flow and Capillaritymentioning

confidence: 99%

Surface patterning of bonded microfluidic channels

Priest

2010

Biomicrofluidics

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Microfluidic channels in which multiple chemical and biological processes can be integrated into a single chip have provided a suitable platform for high throughput screening, chemical synthesis, detection, and alike. These microchips generally exhibit a homogeneous surface chemistry, which limits their functionality. Localized surface modification of microchannels can be challenging due to the nonplanar geometries involved. However, chip bonding remains the main hurdle, with many methods involving thermal or plasma treatment that, in most cases, neutralizes the desired chemical functionality. Postbonding modification of microchannels is subject to many limitations, some of which have been recently overcome. Novel techniques include solution-based modification using laminar or capillary flow, while conventional techniques such as photolithography remain popular. Nonetheless, new methods, including localized microplasma treatment, are emerging as effective postbonding alternatives. This Review focuses on postbonding methods for surface patterning of microchannels.

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“…Barker et al [41] used flow imaging to obtain a more precise characterization than that obtained by current-monitoring measurement in [42]. They imaged the flow in a PMMA channel half coated with bilayer PELs and half coated with a three-layer PELs in the channel direction.…”

Section: Spatially Resolved Eof Measurementsmentioning

confidence: 99%

Surface treatment and characterization: Perspectives to electrophoresis and lab‐on‐chips

et al. 2006

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The control and modification of surface state is a major challenge in bioanalytical sciences, and in particular in electrokinetic separation methods, due to the importance of electroosmosis. This topic has gained recently a renewed interest, associated with the development of "lab-on-chips" systems that extend the range of materials in which separation channels are fabricated. The surface science community has developed through the years a large toolbox of characterization tools and surface modification protocols, which is not yet fully exploited in the bioanalytical world. In this paper, we try and present an overview of these tools, in order to stimulate new ideas for improved and more controlled surface treatment strategies for separations in capillaries and microchannels. We briefly describe some physical and chemical aspects of electroosmosis (global and spatially resolved), streaming current, and streaming potential. We also review the main strategies for surface coating, and compare the advantages of physisorption, well-organized thin self-assembled monolayers, or conversely thick polymer "brushes". Examples of existing applications to electrophoresis in microchannel are also given.

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Control of Flow Direction in Microfluidic Devices with Polyelectrolyte Multilayers

Cited by 185 publications

References 18 publications

Polyelectrolyte‐modified short microchannel for cation separation

Polyelectrolyte‐modified short microchannel for cation separation

Surface patterning of bonded microfluidic channels

Surface treatment and characterization: Perspectives to electrophoresis and lab‐on‐chips

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