Passive flow switching valves on a centrifugal microfluidic platform

Kim, Ji-Tae; Kido, Horacio; Rangel, R. H.; Madou, Marc

doi:10.1016/j.snb.2007.07.079

Cited by 63 publications

(54 citation statements)

References 21 publications

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“…For example, through the actuation of wax valves by a mobile laser system, Cho et al (2007) were able to achieve the multiple valving steps necessary to perform DNA extraction from whole blood. The wax plugs, which acted as physical gating mechanisms, were critical to the assay processing, as the high speeds required for plasma separation from whole blood would have broken any passive valving schemes presented to date in the literature (viz., hydrophobic, hydrophilic, siphon, and Coriolis) (Ducrée et al 2007;Kim et al 2008;Madou et al 2006;Siegrist et al 2010b). We envision the TPP as an alternative technique to using wax plugs or other active valving techniques (Garcia-Cordero et al 2010c;Abi-Samra et al 2011) for the controlled release of fluids due its simplicity.…”

Section: Discussionmentioning

confidence: 99%

Thermo-pneumatic pumping in centrifugal microfluidic platforms

Abi-Samra

Clime

Kong

et al. 2011

Microfluid Nanofluid

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The pumping of fluids in microfluidic discs by centrifugal forces has several advantages, however, centrifugal pumping only permits unidirectional fluid flow, restricting the number of processing steps that can be integrated before fluids reach the edge of the disc. As a solution to this critical limitation, we present a novel pumping technique for the centrifugal microfluidic disc platform, termed the thermo-pneumatic pump (TPP), that enables fluids to be transferred the center of a rotating disc by the thermal expansion of air. The TPP is easy to fabricate as it is a structural feature with no moving components and thermal energy is delivered to the pump via peripheral infrared (IR) equipment, enabling pumping while the disc is in rotation. In this report, an analytical model for the operation of the TPP is presented and experimentally validated. We demonstrate that the experimental behavior of the pump agrees well with theory and that flow rates can be controlled by changing how well the pump absorbs IR energy. Overall, the TPP enables for fluids to be stored near the edge of the disc and transferred to the center on demand, offering significant advantages to the microfluidic disc platform in terms of the handling and storage of liquids.

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Section: Discussionmentioning

confidence: 99%

Thermo-pneumatic pumping in centrifugal microfluidic platforms

Abi-Samra

Clime

Kong

et al. 2011

Microfluid Nanofluid

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“…To date, techniques such as the melting of wax plugs, deposited hydrophobic patches, passive pneumatic valves and capillary force-based valves have been used to control flow in centrifugal microfluidics Kim et al 2008;Mark et al 2009). Among these, capillary valves are among the most commonly used approaches.…”

Section: Introductionmentioning

confidence: 99%

Behavior of capillary valves in centrifugal microfluidic devices prepared by three-dimensional printing

Moore

McCuiston

Mittendorf

et al. 2010

Microfluid Nanofluid

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This paper details the behavior of capillary valves in centrifugal microfluidic devices prepared by three-dimensional (3D), or solid-object, printing. Microfluidic structures containing valve channels with different widths, heights, and radial distances from the center of rotation were studied and compared with extant capillary valve theories. Due to the printing process, the produced valve channels possessed a ridged or ''scalloped'' pattern. Hence, actual channel widths at the widest and narrowest points of the ridged pattern were determined, and used in comparisons between theoretical and empirical values. In addition, variations in contact angle resulting from the ridged pattern were measured and employed in theoretical calculations. For 1-mm high valve channels, the critical angular frequency (rpm) required to overcome capillary valve pressure was found to be independent of width. However, as the height of the valve channel was reduced, the critical rpm was found to become progressively more width-dependent increasing more rapidly for narrower channels. Both of these observations point to a role for feature sharpness, as well as the geometry of the valve channel opening, in valve behavior. Otherwise, valves followed a predictable trend of increasing critical rpm with decreased valve height and decreased radial distance from the rotation center. Using these results as a guide, then, it is possible to prepare centrifugal microfluidic devices by 3D printing with operability comparable to devices prepared by other microfabrication techniques.

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“…This limits the number of sequential operations (e.g., mixing, reagent addition) that can be carried out before the liquid reaches the edge of the platform. There is need for the development of passive pumping methods that do not require moving parts, as these are difficult to integrate on disk and can be complex to fabricate [5]. Both Gorkin [6] and a patent by Lee [7] demonstrate the ability to move liquid from the outer edge of the disk back towards the center in order to overcome this limitation.…”

Section: Open Accessmentioning

confidence: 99%

Displacement Pumping of Liquids Radially Inward on Centrifugal Microfluidic Platforms in Motion

2011

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Abstract:We describe two novel centrifugal microfluidic platform designs that enable passive pumping of liquids radially inward while the platform is in motion. The first design uses an immiscible liquid to displace an aqueous solution back towards the center of the platform, while the second design uses an arbitrary pumping liquid with a volume of air between it and the solution being pumped. Both designs demonstrated the ability to effectively pump 55% to 60% of the solution radially inward at rotational frequencies as low as 400 rpm (6.7 Hz) to 700 rpm (11.7 Hz). The pumping operations reached completion within 120 s and 400 s respectively. These platform designs for passive pumping of liquids do not require moving parts or complex fabrication techniques. They offer great potential for increasing the number of sequential operations that can be performed on centrifugal microfluidic platforms, thereby reducing a fundamental limitation often associated with these platforms.

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Passive flow switching valves on a centrifugal microfluidic platform

Cited by 63 publications

References 21 publications

Thermo-pneumatic pumping in centrifugal microfluidic platforms

Thermo-pneumatic pumping in centrifugal microfluidic platforms

Behavior of capillary valves in centrifugal microfluidic devices prepared by three-dimensional printing

Displacement Pumping of Liquids Radially Inward on Centrifugal Microfluidic Platforms in Motion

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