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Hydrodynamic guiding for addressing subsets of immobilized cells and molecules in microfluidic systems.

Brevig T, Krühne U, Kahn RA, Ahl T, Beyer M, Pedersen LH - BMC Biotechnol. (2003)

Bottom Line: The use of hydrodynamic guiding made multiple and dynamic experimental conditions on a small surface area possible.The ability to change the direction of flow and produce two-dimensional grids can increase the number of reactions per surface area even further.The described microfluidic system is widely applicable, and can take advantage of surfaces produced by current and future techniques for patterning in the micro- and nanometer scale.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Molecular Characterization, Biotechnological Institute, Kogle Allé 2, DK-2970 Hørsholm, Denmark. tbr@bioteknologisk.dk

ABSTRACT

Background: The interest in microfluidics and surface patterning is increasing as the use of these technologies in diverse biomedical applications is substantiated. Controlled molecular and cellular surface patterning is a costly and time-consuming process. Methods for keeping multiple separate experimental conditions on a patterned area are, therefore, needed to amplify the amount of biological information that can be retrieved from a patterned surface area. We describe, in three examples of biomedical applications, how this can be achieved in an open microfluidic system, by hydrodynamically guiding sample fluid over biological molecules and living cells immobilized on a surface.

Results: A microfluidic format of a standard assay for cell-membrane integrity showed a fast and dose-dependent toxicity of saponin on mammalian cells. A model of the interactions of human mononuclear leukocytes and endothelial cells was established. By contrast to static adhesion assays, cell-cell adhesion in this dynamic model depended on cytokine-mediated activation of both endothelial and blood cells. The microfluidic system allowed the use of unprocessed blood as sample material, and a specific and fast immunoassay for measuring the concentration of C-reactive protein in whole blood was demonstrated.

Conclusion: The use of hydrodynamic guiding made multiple and dynamic experimental conditions on a small surface area possible. The ability to change the direction of flow and produce two-dimensional grids can increase the number of reactions per surface area even further. The described microfluidic system is widely applicable, and can take advantage of surfaces produced by current and future techniques for patterning in the micro- and nanometer scale.

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Related in: MedlinePlus

Analysis of the lane variation using the streptavidin-biotin affinity reaction. A microfluidic chamber with the same design and dimensions as described in Figure 1, but etched into a silicon chip and closed by bonding, was coated with streptavidin. Fluorescein-labeled biotin was then hydrodynamically guided in 50-μm-wide lanes over an area of 1000 × 1000 μm (arrows indicate the directions of flow). Ten lanes were applied evenly, and the procedure was repeated in a perpendicular direction, resulting in a grid of 100 intersections. The bended shape of the lanes in the lower and left part of the photomicrograph resulted from the hydrodynamic bending of the flow due to the quadratic shape of the microfluidic chamber. Scale bar, 100 μm.
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Figure 2: Analysis of the lane variation using the streptavidin-biotin affinity reaction. A microfluidic chamber with the same design and dimensions as described in Figure 1, but etched into a silicon chip and closed by bonding, was coated with streptavidin. Fluorescein-labeled biotin was then hydrodynamically guided in 50-μm-wide lanes over an area of 1000 × 1000 μm (arrows indicate the directions of flow). Ten lanes were applied evenly, and the procedure was repeated in a perpendicular direction, resulting in a grid of 100 intersections. The bended shape of the lanes in the lower and left part of the photomicrograph resulted from the hydrodynamic bending of the flow due to the quadratic shape of the microfluidic chamber. Scale bar, 100 μm.

Mentions: Fluorescein-labeled biotin was guided sequentially in ten lanes over immobilized streptavidin. The flow direction was then changed, and another ten lanes were guided over the same area, but perpendicularly to the first set of lanes. The even shape of the resulting two-dimensional grid, shown in Figure 2, illustrates the small variation within and between lanes produced by hydrodynamic guiding. The fluorescence intensity decreased slightly along the length of the lanes.


Hydrodynamic guiding for addressing subsets of immobilized cells and molecules in microfluidic systems.

Brevig T, Krühne U, Kahn RA, Ahl T, Beyer M, Pedersen LH - BMC Biotechnol. (2003)

Analysis of the lane variation using the streptavidin-biotin affinity reaction. A microfluidic chamber with the same design and dimensions as described in Figure 1, but etched into a silicon chip and closed by bonding, was coated with streptavidin. Fluorescein-labeled biotin was then hydrodynamically guided in 50-μm-wide lanes over an area of 1000 × 1000 μm (arrows indicate the directions of flow). Ten lanes were applied evenly, and the procedure was repeated in a perpendicular direction, resulting in a grid of 100 intersections. The bended shape of the lanes in the lower and left part of the photomicrograph resulted from the hydrodynamic bending of the flow due to the quadratic shape of the microfluidic chamber. Scale bar, 100 μm.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC183863&req=5

Figure 2: Analysis of the lane variation using the streptavidin-biotin affinity reaction. A microfluidic chamber with the same design and dimensions as described in Figure 1, but etched into a silicon chip and closed by bonding, was coated with streptavidin. Fluorescein-labeled biotin was then hydrodynamically guided in 50-μm-wide lanes over an area of 1000 × 1000 μm (arrows indicate the directions of flow). Ten lanes were applied evenly, and the procedure was repeated in a perpendicular direction, resulting in a grid of 100 intersections. The bended shape of the lanes in the lower and left part of the photomicrograph resulted from the hydrodynamic bending of the flow due to the quadratic shape of the microfluidic chamber. Scale bar, 100 μm.
Mentions: Fluorescein-labeled biotin was guided sequentially in ten lanes over immobilized streptavidin. The flow direction was then changed, and another ten lanes were guided over the same area, but perpendicularly to the first set of lanes. The even shape of the resulting two-dimensional grid, shown in Figure 2, illustrates the small variation within and between lanes produced by hydrodynamic guiding. The fluorescence intensity decreased slightly along the length of the lanes.

Bottom Line: The use of hydrodynamic guiding made multiple and dynamic experimental conditions on a small surface area possible.The ability to change the direction of flow and produce two-dimensional grids can increase the number of reactions per surface area even further.The described microfluidic system is widely applicable, and can take advantage of surfaces produced by current and future techniques for patterning in the micro- and nanometer scale.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Molecular Characterization, Biotechnological Institute, Kogle Allé 2, DK-2970 Hørsholm, Denmark. tbr@bioteknologisk.dk

ABSTRACT

Background: The interest in microfluidics and surface patterning is increasing as the use of these technologies in diverse biomedical applications is substantiated. Controlled molecular and cellular surface patterning is a costly and time-consuming process. Methods for keeping multiple separate experimental conditions on a patterned area are, therefore, needed to amplify the amount of biological information that can be retrieved from a patterned surface area. We describe, in three examples of biomedical applications, how this can be achieved in an open microfluidic system, by hydrodynamically guiding sample fluid over biological molecules and living cells immobilized on a surface.

Results: A microfluidic format of a standard assay for cell-membrane integrity showed a fast and dose-dependent toxicity of saponin on mammalian cells. A model of the interactions of human mononuclear leukocytes and endothelial cells was established. By contrast to static adhesion assays, cell-cell adhesion in this dynamic model depended on cytokine-mediated activation of both endothelial and blood cells. The microfluidic system allowed the use of unprocessed blood as sample material, and a specific and fast immunoassay for measuring the concentration of C-reactive protein in whole blood was demonstrated.

Conclusion: The use of hydrodynamic guiding made multiple and dynamic experimental conditions on a small surface area possible. The ability to change the direction of flow and produce two-dimensional grids can increase the number of reactions per surface area even further. The described microfluidic system is widely applicable, and can take advantage of surfaces produced by current and future techniques for patterning in the micro- and nanometer scale.

Show MeSH
Related in: MedlinePlus