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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

(Top) schematic representation of slug generator. Two chambers (A and B) are separated by microvalve V5. Each chamber has a reagent inlet port and valve, and a vent outlet channel and valve in an adjacent chamber. Carrier (pressurized nitrogen) enters at the left, controlled by valve V1, to merge chamber contents and to push slugs to the outlet. (Bottom) detailed sequence of valve states for slug generation with duration shown in parentheses beside the name of the step. A micrograph of the actual chip generating slugs from colored liquids (water with food dye) is also shown for each step. The purpose of the sealing steps is to ensure that valves have sufficient time to close completely before other valves are opened (tseal = 100 ms)
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Fig2: (Top) schematic representation of slug generator. Two chambers (A and B) are separated by microvalve V5. Each chamber has a reagent inlet port and valve, and a vent outlet channel and valve in an adjacent chamber. Carrier (pressurized nitrogen) enters at the left, controlled by valve V1, to merge chamber contents and to push slugs to the outlet. (Bottom) detailed sequence of valve states for slug generation with duration shown in parentheses beside the name of the step. A micrograph of the actual chip generating slugs from colored liquids (water with food dye) is also shown for each step. The purpose of the sealing steps is to ensure that valves have sufficient time to close completely before other valves are opened (tseal = 100 ms)

Mentions: Fluids were delivered to the chip through PTFE microbore tubing, connected via short stainless steel tubes inserted directly into the chip. Liquids A and B were manually primed up to the valves V4 and V6 on the chip (Fig. 2) using the vent channels. Microvalve control lines were filled with water. On-chip valves were actuated by pressurizing the corresponding control channel to 410 kPag via electronic solenoid valves (Series S070, SMC, Japan). The corresponding valve burst pressure was measured to be about 280 kPag, suggesting that fluid driving pressures up to about 210 kPag could be reliably used in the chip. All valves were automatically controlled through a data acquisition module (USB-4750, Advantech, USA) driven by a custom software program written in LabView (National Instruments, USA).Fig. 2


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)

(Top) schematic representation of slug generator. Two chambers (A and B) are separated by microvalve V5. Each chamber has a reagent inlet port and valve, and a vent outlet channel and valve in an adjacent chamber. Carrier (pressurized nitrogen) enters at the left, controlled by valve V1, to merge chamber contents and to push slugs to the outlet. (Bottom) detailed sequence of valve states for slug generation with duration shown in parentheses beside the name of the step. A micrograph of the actual chip generating slugs from colored liquids (water with food dye) is also shown for each step. The purpose of the sealing steps is to ensure that valves have sufficient time to close completely before other valves are opened (tseal = 100 ms)
© Copyright Policy
Related In: Results  -  Collection

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

Fig2: (Top) schematic representation of slug generator. Two chambers (A and B) are separated by microvalve V5. Each chamber has a reagent inlet port and valve, and a vent outlet channel and valve in an adjacent chamber. Carrier (pressurized nitrogen) enters at the left, controlled by valve V1, to merge chamber contents and to push slugs to the outlet. (Bottom) detailed sequence of valve states for slug generation with duration shown in parentheses beside the name of the step. A micrograph of the actual chip generating slugs from colored liquids (water with food dye) is also shown for each step. The purpose of the sealing steps is to ensure that valves have sufficient time to close completely before other valves are opened (tseal = 100 ms)
Mentions: Fluids were delivered to the chip through PTFE microbore tubing, connected via short stainless steel tubes inserted directly into the chip. Liquids A and B were manually primed up to the valves V4 and V6 on the chip (Fig. 2) using the vent channels. Microvalve control lines were filled with water. On-chip valves were actuated by pressurizing the corresponding control channel to 410 kPag via electronic solenoid valves (Series S070, SMC, Japan). The corresponding valve burst pressure was measured to be about 280 kPag, suggesting that fluid driving pressures up to about 210 kPag could be reliably used in the chip. All valves were automatically controlled through a data acquisition module (USB-4750, Advantech, USA) driven by a custom software program written in LabView (National Instruments, USA).Fig. 2

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