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Microfluidic device for robust generation of two-component liquid-in-air slugs with individually controlled composition.

Liu K, Chen YC, Tseng HR, Shen CK, van Dam RM - Microfluid Nanofluidics (2010)

Bottom Line: The use of microvalves in this approach enables robust operation with different liquids, and also enables one to work with extremely small samples, even down to a few slug volumes.The latter is important for applications involving precious reagents such as optimizing the reaction conditions for radiolabeling biological molecules as tracers for positron emission tomography.ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s10404-010-0617-0) contains supplementary material, which is available to authorized users.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular & Medical Pharmacology, Crump Institute for Molecular Imaging, California NanoSystems Institute, David Geffen School of Medicine, University of California, Los Angeles, 570 Westwood Plaza, Los Angeles, CA 90095 USA.

ABSTRACT
Using liquid slugs as microreactors and microvessels enable precise control over the conditions of their contents on short-time scales for a wide variety of applications. Particularly for screening applications, there is a need for control of slug parameters such as size and composition. We describe a new microfluidic approach for creating slugs in air, each comprising a size and composition that can be selected individually for each slug. Two-component slugs are formed by first metering the desired volume of each reagent, merging the two volumes into an end-to-end slug, and propelling the slug to induce mixing. Volume control is achieved by a novel mechanism: two closed chambers on the chip are initially filled with air, and a valve in each is briefly opened to admit one of the reagents. The pressure of each reagent can be individually selected and determines the amount of air compression, and thus the amount of liquid that is admitted into each chamber. We describe the theory of operation, characterize the slug generation chip, and demonstrate the creation of slugs of different compositions. The use of microvalves in this approach enables robust operation with different liquids, and also enables one to work with extremely small samples, even down to a few slug volumes. The latter is important for applications involving precious reagents such as optimizing the reaction conditions for radiolabeling biological molecules as tracers for positron emission tomography. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s10404-010-0617-0) contains supplementary material, which is available to authorized users.

No MeSH data available.


Related in: MedlinePlus

a Photograph of PDMS microfluidic slug-generator. Tubing is connected to inlets and valve control channels via a custom connector developed in our laboratory. b Detail of slug generator. Control channels and microvalves have been filled with red food dye. Yellow food dye has been used to visualize the filling chambers (A and B) and associated reagent inlets. In this image, a slug of 1:1 ratio of liquids A and B is being prepared. Each filling chamber is about 1400-μm long, 300-μm wide, and 60-μm tall. Vent ports are shown in green. The slug generator is coupled to an outlet port in this chip, but would be directly coupled with other on-chip components for many applications
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Fig1: a Photograph of PDMS microfluidic slug-generator. Tubing is connected to inlets and valve control channels via a custom connector developed in our laboratory. b Detail of slug generator. Control channels and microvalves have been filled with red food dye. Yellow food dye has been used to visualize the filling chambers (A and B) and associated reagent inlets. In this image, a slug of 1:1 ratio of liquids A and B is being prepared. Each filling chamber is about 1400-μm long, 300-μm wide, and 60-μm tall. Vent ports are shown in green. The slug generator is coupled to an outlet port in this chip, but would be directly coupled with other on-chip components for many applications

Mentions: The microfluidic slug generator (Fig. 1) was implemented as a two-layer polydimethylsiloxane (PDMS) chip according to common design and fabrication practices (Melin and Quake 2007). The upper layer of channels contains the fluidic channel network, consisting of reagent inlets, filling chambers, and slug output, while the lower layer contains microvalve control channels. Integrated “pinch valves” are created at each location where a control channel crosses directly below a fluid channel (Studer et al. 2004; Unger et al. 2000). The thin, elastic, PDMS membrane between the two channels can be actuated by applying pressure to the control channel, thus locally pinching off (closing) the fluid channel.Fig. 1


Microfluidic device for robust generation of two-component liquid-in-air slugs with individually controlled composition.

Liu K, Chen YC, Tseng HR, Shen CK, van Dam RM - Microfluid Nanofluidics (2010)

a Photograph of PDMS microfluidic slug-generator. Tubing is connected to inlets and valve control channels via a custom connector developed in our laboratory. b Detail of slug generator. Control channels and microvalves have been filled with red food dye. Yellow food dye has been used to visualize the filling chambers (A and B) and associated reagent inlets. In this image, a slug of 1:1 ratio of liquids A and B is being prepared. Each filling chamber is about 1400-μm long, 300-μm wide, and 60-μm tall. Vent ports are shown in green. The slug generator is coupled to an outlet port in this chip, but would be directly coupled with other on-chip components for many applications
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2944379&req=5

Fig1: a Photograph of PDMS microfluidic slug-generator. Tubing is connected to inlets and valve control channels via a custom connector developed in our laboratory. b Detail of slug generator. Control channels and microvalves have been filled with red food dye. Yellow food dye has been used to visualize the filling chambers (A and B) and associated reagent inlets. In this image, a slug of 1:1 ratio of liquids A and B is being prepared. Each filling chamber is about 1400-μm long, 300-μm wide, and 60-μm tall. Vent ports are shown in green. The slug generator is coupled to an outlet port in this chip, but would be directly coupled with other on-chip components for many applications
Mentions: The microfluidic slug generator (Fig. 1) was implemented as a two-layer polydimethylsiloxane (PDMS) chip according to common design and fabrication practices (Melin and Quake 2007). The upper layer of channels contains the fluidic channel network, consisting of reagent inlets, filling chambers, and slug output, while the lower layer contains microvalve control channels. Integrated “pinch valves” are created at each location where a control channel crosses directly below a fluid channel (Studer et al. 2004; Unger et al. 2000). The thin, elastic, PDMS membrane between the two channels can be actuated by applying pressure to the control channel, thus locally pinching off (closing) the fluid channel.Fig. 1

Bottom Line: The use of microvalves in this approach enables robust operation with different liquids, and also enables one to work with extremely small samples, even down to a few slug volumes.The latter is important for applications involving precious reagents such as optimizing the reaction conditions for radiolabeling biological molecules as tracers for positron emission tomography.ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s10404-010-0617-0) contains supplementary material, which is available to authorized users.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular & Medical Pharmacology, Crump Institute for Molecular Imaging, California NanoSystems Institute, David Geffen School of Medicine, University of California, Los Angeles, 570 Westwood Plaza, Los Angeles, CA 90095 USA.

ABSTRACT
Using liquid slugs as microreactors and microvessels enable precise control over the conditions of their contents on short-time scales for a wide variety of applications. Particularly for screening applications, there is a need for control of slug parameters such as size and composition. We describe a new microfluidic approach for creating slugs in air, each comprising a size and composition that can be selected individually for each slug. Two-component slugs are formed by first metering the desired volume of each reagent, merging the two volumes into an end-to-end slug, and propelling the slug to induce mixing. Volume control is achieved by a novel mechanism: two closed chambers on the chip are initially filled with air, and a valve in each is briefly opened to admit one of the reagents. The pressure of each reagent can be individually selected and determines the amount of air compression, and thus the amount of liquid that is admitted into each chamber. We describe the theory of operation, characterize the slug generation chip, and demonstrate the creation of slugs of different compositions. The use of microvalves in this approach enables robust operation with different liquids, and also enables one to work with extremely small samples, even down to a few slug volumes. The latter is important for applications involving precious reagents such as optimizing the reaction conditions for radiolabeling biological molecules as tracers for positron emission tomography. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s10404-010-0617-0) contains supplementary material, which is available to authorized users.

No MeSH data available.


Related in: MedlinePlus