Capillary stop-flow junction having improved stability against accidental fluid flow

• US 5,230,866 A
• Filed: 03/01/1991
• Issued: 07/27/1993
• Est. Priority Date: 03/01/1991
• Status: Expired due to Term

• Current Assignee: Roche Diagnostics Operations Incorporated (Roche Holding AG)
• Original Assignee: Biotrack, Inc. (Novartis Ag)
• Inventors: Gorin, Michael, Shartle, Robert, Besemer, Donald
• Primary Examiner(s): Warden, Robert J.
• Assistant Examiner(s): Kim, Christopher Y.
• Application Number:
  US07/663,217
• Time in Patent Office: 879 Days
• Field of Search: 422/100, 422/102, 422/103, 422/68.1, 422/81, 422/82, 436/45, 436/179, 436/180, 435/810, 435/301, 73/864.71, 73/865.71, 383/45, 383/100, 383/103
• US Class Current: 422/68.1
• CPC Class Codes: B01L 2200/0684 Venting, avoiding backpressure, avoid gas bubbles
• CPC Class Codes: B01L 2200/10 Integrating sample preparation and analysis in single entity, e.g. lab-on-a-chip concept
• CPC Class Codes: B01L 2300/0816 Cards, e.g. flat sample carriers usually with flow in two horizontal directions
• CPC Class Codes: B01L 2300/0867 Multiple inlets and one sample wells, e.g. mixing, dilution
• CPC Class Codes: B01L 2300/087 Multiple sequential chambers
• CPC Class Codes: B01L 2300/0887 Laminated structure
• CPC Class Codes: B01L 2400/0406 capillary forces
• CPC Class Codes: B01L 2400/0457 passive flow or gravitation
• CPC Class Codes: B01L 2400/0683 mechanically breaking a wall or membrane within a channel or chamber
• CPC Class Codes: B01L 2400/0688 surface tension valves, capillary stop, capillary break
• CPC Class Codes: B01L 2400/0694 vents used to stop and induce flow, backpressure valves
• CPC Class Codes: B01L 3/502723 characterised by venting arrangements
• CPC Class Codes: B01L 3/502738 characterised by integrated valves microvalves F16K99/0001
• CPC Class Codes: G01N 1/38 Diluting, dispersing or mixing samples
• CPC Class Codes: G01N 33/04 Dairy products
• CPC Class Codes: Y10T 436/111666 Utilizing a centrifuge or compartmented rotor
• CPC Class Codes: Y10T 436/25625 Dilution
• CPC Class Codes: Y10T 436/2575 Volumetric liquid transfer

Abstract

A capillary stop-flow junction located in a housing at an end of a capillary passageway used to transport a liquid and at the beginning of a non-capillary internal chamber in the housing, in which the stop-flow junction contains an improvement which comprises 1) means for selectively trapping a gas in the capillary passageway and non-capillary chamber, wherein when the means for trapping is activated and the liquid enters the capillary passageway, the gas is compressed by the liquid as the liquid flows through the capillary channel and stops flowing at the stop-flow junction; or 2) a stop-flow nozzle surrounding the capillary passageway and projecting into the chamber; or 3) the stop-flow junction being formed from a single housing body member; or 4) a rupture junction in the capillary pathway, wherein the rupture junction is a stop-flow junction providing less maximum available back pressure than the capillary stop-flow junction. Diluters capable of serial dilution that use the stop-flow junctions of the invention are also described.

Claims

1. In a device combination which comprises an electronic instrument and an analytical cartridge adapted to removably fit into said instrument for carrying out an analytical assay, wherein said cartridge comprises a housing containing a capillary stop-flow junction located at a junction where a capillary passageway used to transport a liquid in said housing enters a non-capillary internal chamber in said housing, an improvement which comprises:

means for selectively trapping gas in said capillary passageway and non-capillary chamber, whereby when said means for trapping is activated and said liquid enters said capillary passageway, said gas is compressed by said liquid as said liquid flows through said capillary channel and said liquid stops flowing at said stop-flow junction, wherein said means for selectively trapping gas comprises an vent opening in said housing, a vent passageway connecting said chamber to atmosphere surrounding said cartridge at said vent, and a sealing member located externally to said housing which is capable of selectively closing said vent opening, wherein said sealing member is located in and operated by said electronic instrument.

2. The device combination of claim 1, wherein said vent passageway comprises a capillary passageway and a non-capillary vent-surge chamber.

3. The device combination of claim 1, wherein said sealing member comprises a flexible pad that reversibly contacts said vent opening.

4. The device combination of claim 1, wherein internal pressure of said compressed gas balances head pressure of said sample at said stop-flow junction when sample has stopped flowing at said junction.

5. A vent-assisted capillary stop-flow junction comprising a housing surrounded by a gaseous atmosphere and an electronic instrument into which said housing removably fits, wherein (1) said housing comprising:

a. an internal chamber;

b. liquid receiving means for accepting a liquid;

c. a capillary channel connecting said liquid receiving means to said chamber; and

d. a channel leading out of said chamber and connecting said chamber to the atmosphere and surrounding said housing;

(2) said electronic instrument comprises means for selectively closing said channel and sealing said chamber from the atmosphere;

wherein when (1) said means for selectively closing is activated and gas is trapped in said capillary passageway and said chamber and (2) said liquid is concurrently applied to said means for accepting a liquid, said liquid flows through said capillary channel, compresses air trapped in said housing by said means for trapping, and stops flowing at said stop-flow junction.

6. The vent-assisted capillary stop-flow junction of claim 5 wherein said vent passageway comprises a capillary passageway and a non-capillary vent-surge chamber.

7. The vent-assisted capillary stop-flow junction of claim 5 wherein said sealing member comprises a flexible pad that reversibly contacts said vent opening.

8. The vent-assisted capillary stop-flow junction of claim 5, wherein internal pressure of said compressed gas balances head pressure of said sample at said stop-flow junction when sample has stopped flowing at said junction.

9. A method for increasing stability of a capillary stop-flow junction in a housing surrounded by a gaseous atmosphere, which comprises the steps of:

(1) providing a housing having;

i. an internal chamber of non-capillary dimensions;

ii. liquid receiving means for accepting a liquid;

iii. a capillary channel connecting said sample receiving means to said chamber;

iv. said stop-flow junction at the intersection of said capillary channel and said chamber; and

v. a venting channel leading out of said chamber and connecting said chamber to the atmosphere surrounding said housing;

(2) inserting said housing into a device having means for selectively closing said venting channel and sealing said chamber from the atmosphere; and

(3) closing said venting channel prior to applying said liquid to said means for accepting a liquid, whereby said liquid flows through said capillary channel and stops flowing at said stop-flow junction.

10. The method of claim 9, wherein said venting channel has a volume selected so that compression of air trapped in said capillary channel, said chamber, and said venting channel produces an internal pressure that opposes flow of said liquid that is no greater than hydrostatic pressure acting in the direction of said flow.