Metering arrangement in a capillary driven fluid system and method for the same
Inventors
Assignees
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Publication Number
US-11618020-B2
Publication Date
2023-04-04
Expiration Date
Abstract
The disclosure relates to an arrangement (100) in a capillary driven fluid system for metering a predetermined volume of sample fluid. The arrangement comprises a sample reservoir (SR) arranged to receive a sample fluid, a first channel (C1) which is in fluid communication with the sample reservoir (SR) and which branches off into a second channel (C2) ending at a first valve (V1) and a third channel (C3) ending at a second valve (V2). The second channel (C2) and the third channel (C3) together have a predetermined volume, and the first channel (C1) is arranged to draw sample fluid from the sample reservoir (SR) by use of capillary forces to fill the second channel (C2) and the third channel (C3) with the predetermined volume of sample fluid. By selectively opening the first valve (V1) and the second valve (V2), a capillary driven flow may be formed, thereby causing the predetermined volume of sample fluid to flow out through the first valve (V1).
Core Innovation
The invention provides an arrangement in a capillary driven fluid system for metering a predetermined volume of sample fluid using capillary forces. A sample reservoir (SR) receives the sample fluid and a first channel (C1) in fluid communication with the sample reservoir (SR) branches into a second channel (C2) ending at a first valve (V1) and a third channel (C3) ending at a second valve (V2), wherein the second channel (C2) and the third channel (C3) together have a predetermined volume that is filled with sample fluid drawn from the sample reservoir (SR) by capillary forces.
The arrangement further includes a capillary pump (CP1) arranged to empty the sample reservoir (SR) after the second channel (C2) and the third channel (C3) have been filled with sample fluid, and before the buffer fluid in the fourth channel (C4) reaches the second valve (V2). After the sample reservoir (SR) has been emptied, a buffer reservoir (BR) provides buffer fluid via a fourth channel (C4) fluidically connected to the second valve (V2), wherein the fourth channel (C4) draws buffer fluid by capillary forces and is arranged to open the second valve (V2) as the buffer fluid reaches the second valve (V2).
A first control circuit (T1) comprising a first fluidic circuit connects the first valve (V1) to the buffer reservoir (BR), wherein the first fluidic circuit draws buffer fluid from the buffer reservoir (BR) and opens the first valve (V1) as buffer fluid reaches the first valve (V1). The first control circuit (T1) is arranged to open the first valve (V1) after the sample reservoir (SR) has been emptied, whereby a capillary driven flow arises in said fluid path and causes the predetermined volume of sample fluid in the second (C2) and third (C3) channels to flow out through the first valve (V1).
Claims Coverage
One independent claim defines the core arrangement. The inventive features centered in the independent claim are four in number, with dependent claims adding additional valves, control circuits, venting features, downstream dilution and mixing, and other capillary-pressure or flow-control elements.
Capillary metering of predetermined sample volume in branched channels
A sample reservoir (SR) receives a sample fluid and a first channel (C1) branches into a second channel (C2) ending at a first valve (V1) and a third channel (C3) ending at a second valve (V2), wherein the second channel (C2) and the third channel (C3) together have a predetermined volume; the first channel (C1) draws sample fluid from the sample reservoir (SR) by capillary forces to fill the second channel (C2) and the third channel (C3) with the predetermined volume.
Timed capillary emptying of sample reservoir before buffer reaches second valve
A capillary pump (CP1) empties the sample reservoir (SR) after the second channel (C2) and the third channel (C3) have been filled with sample fluid, and before the buffer fluid in the fourth channel (C4) reaches the second valve (V2).
Capillary-triggered opening of fluid path via buffer and second valve
A buffer reservoir (BR) receives a buffer fluid and a fourth channel (C4) connects the buffer reservoir (BR) to the second valve (V2), wherein the fourth channel (C4) draws buffer fluid by capillary forces after the sample reservoir (SR) has been emptied, and opens the second valve (V2) as buffer fluid in the fourth channel (C4) reaches the second valve (V2), thereby opening a fluid path including the fourth channel (C4), the third channel (C3), and the second channel (C2) from the buffer reservoir (BR) to the first valve (V1).
Control-circuit opening of first valve after sample emptying to drive outflow
A first control circuit (T1) comprising a first fluidic circuit connects the first valve (V1) to the buffer reservoir (BR), the first fluidic circuit being arranged to draw buffer fluid and open the first valve (V1) as buffer fluid reaches the first valve (V1); the first control circuit is arranged to open the first valve (V1) after the sample reservoir (SR) has been emptied, whereby a capillary driven flow arises in the fluid path and causes the predetermined volume of sample fluid in the second (C2) and third (C3) channels to flow out through the first valve (V1).
Across the independent claim, the coverage centers on capillary-force filling of a predetermined sample volume in branched channels, timed capillary emptying of the sample reservoir via CP1, capillary-force buffer delivery that opens the second valve to establish a fluid path, and control-circuit timing that opens the first valve to drive outflow of the metered sample volume.
Stated Advantages
Precise metering of a predetermined volume of sample fluid using capillary forces and capillary pump timing without active power, as reflected in the described capillary driven flow and sequencing.
Documented Applications
Downstream dilution and mixing for assays including cell counting/diagnostics, as described with a detection/counting detector and diagnostic system/cartidge concepts.
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