Capillary transport device having means for increasing the viscosity of the transported liquid

• US 4,549,952 A
• Filed: 10/03/1983
• Issued: 10/29/1985
• Est. Priority Date: 11/22/1982
• Status: Expired due to Fees

• Current Assignee: Clinical Diagnostic Systems Inc.
• Original Assignee: Eastman Kodak Company
• Inventors: Columbus, Richard L.
• Primary Examiner(s): Turk, Arnold
• Application Number:
  US06/537,553
• Time in Patent Office: 757 Days
• Field of Search: 422/100, 422/58, 137/13, 137/D10, 137/251, 138/44, 138/45, 73/864.02, 73/864.72, 204/409, 204/416, 204/418, 204/435, 141/31, 141/99, 141/100
• US Class Current: 204/416
• CPC Class Codes: B01L 2300/0816 Cards, e.g. flat sample carriers usually with flow in two horizontal directions
• CPC Class Codes: B01L 2300/0887 Laminated structure
• CPC Class Codes: B01L 2400/0406 capillary forces
• CPC Class Codes: B01L 2400/0661 shape memory polymer valves
• CPC Class Codes: B01L 2400/084 Passive control of flow resistance
• CPC Class Codes: B01L 3/502746 characterised by the means for controlling flow resistance, e.g. flow controllers, baffles B01L3/502738 takes precedence
• CPC Class Codes: G01N 27/307 Disposable laminated or multilayered electrodes G01N27/3272 takes precedence
• CPC Class Codes: Y10T 137/0391 Affecting flow by the addition of material or energy

Abstract

A capillary transport device is disclosed, suitable for use as an ion bridge for potentiometric test elements. Such device has an internal capillary transport passage, and two access apertures for separate access of two different liquids to two spaced-apart regions of the passage. To control the liquid flow rate within the passage, there is disposed on at least a portion of at least one of the surfaces of the passage between the two regions, means for (a) increasing the viscosity of the liquid while it is flowing past at least one surface, and (b) at the same time maintaining such flow continuous within the passage.

Claims

1. In a liquid transport device for simultaneously transporting two different aqueous liquids within a capillary passage, said device comprising two opposed liquid transport surfaces spaced apart a distance effective to induce capillary flow between said surfaces of introduced liquid and to create the capillary passage;

and access means, including two apertures, for respectively admitting said different liquids to said passage from the exterior of the device to two spaced-apart regions of the passage;

the improvement wherein there is disposed on at least one of said surfaces, spaced a capillary distance from the other surface, control means for (a) increasing the viscosity of the liquid while it is flowing past said at least one surface, and (b) at the same time maintaining such flow continuous within said passage,

whereby the rate of flow within said passage is reduced and any displacement force created when two liquids with unequal surface tensions meet within said passage, is countered.

2. A device as defined in claim 1, wherein said control means comprises a water-swellable composition disposed on said at least one surface.

4. The invention defined in claim 2 or 3, wherein (1) said regions are spaced, and (2), said composition is water-swellable, by an amount and at a rate such that the liquid introduced at one region travels one-half the distance between said regions in a time of from 2 seconds to about 15 seconds.

3. In a liquid transport device for simultaneously transporting two different aqueous liquids within a capillary passage, said device comprising two opposed liquid transport surfaces spaced apart a distance effective to induce capillary flow between said surfaces of introduced liquid and to create the capillary passage;

and access means, including two apertures, for respectively admitting said different liquids to said passage from the exterior of the device to two spaced-apart regions of the passage;

the improvement wherein a water-swellable composition is disposed on at least one of said surfaces, between said regions so as to predeterminedly constrain, by swelling, liquid flow within said passage between said regions to a reduced, non-zero rate.

6. A device as defined in claim 3 or 5, wherein said composition comprises a material selected from the group consisting of gelatin, a gelatin derivative, starch, polysaccharide, hydrogel, gum arabic, agarose, zein, casein, pectin, a derivative of collagen, collodion, agar-agar, arrowroot, polyvinyl alcohol, polyvinyl pyrrolidone, a cellulose derivative, and a mixture of any of said materials.

5. In a liquid transport device for simultaneously transporting two different liquids within a capillary passage, said device comprising two opposed liquid transport surfaces spaced apart a distance effective to induce capillary flow between said surfaces of introduced liquid and to create the capillary passage;

and access means, including two apertures, for simultaneously admitting liquids to said passage from the exterior of the device, a portion of said passage between said apertures being constructed to bring together at a junction between the apertures, two such liquids introduced to said passage,

the improvement wherein a water-swellable composition is disposed on at least one of said surfaces, between said apertures to form an initial capillary spacing between said composition and the other of said surfaces,

said passage between said apertures having a predetermined length and said composition being water-swellable by an amount and at a predetermined rate such that said initial capillary spacing is reduced by at least about 25% by the time liquid introduced into one of said apertures flows to said junction.

7. In an ion bridge fluidly connecting at least two ion-selective electrodes comprising the reagents operative to provide a determination of the activity of an ionic analyte in a liquid having a surface tension between about 25 and about 75 dynes/cm², said bridge comprising

two opposed liquid transport surfaces spaced apart a distance effective to induce capillary flow between said surfaces of introduced liquid and to create a transport passage, said passage having portions that are in separate liquid communication with each of said electrodes;

and access means, including two apertures, for respectively admitting liquids from the exterior of said bridge to two spaced-apart regions of the passage;

the improvement wherein there is disposed on at least one of said surfaces, spaced a capillary distance from the other surface, control means for (a) increasing the viscosity of the liquid while it is flowing past said at least one surface, and (b) at the same time maintaining such flow continuous within said passage,

whereby the rate of flow within said passage is reduced and any displacement force created when two liquids with unequal surface tensions meet within said passage, is countered.

8. A bridge as defined in claim 7, wherein said control means comprises a water-swellable composition disposed on said at least one surface.

10. A bridge as defined in claim 8 or 9, wherein (1) said regions are spaced, and (2), said composition is water-swellable, by an amount and at a rate such that the liquid introduced at one region travels one-half the distance between said regions in a time of from 2 seconds to about 15 seconds.

9. In an ion bridge fluidly connecting at least two ion-selective electrodes comprising the reagents operative to provide a determination of the activity of an ionic analyte in a liquid having a surface tension between about 25 and about 75 dynes/cm², said bridge comprising

two opposed liquid transport surfaces spaced apart a distance effective to induce capillary flow between said surfaces of introduced liquid and to create a transport passage, said passage having portions that are in separate liquid communication with each of said electrodes;

and access means, including two apertures, for respectively admitting liquids from the exterior of said bridge to two spaced-apart regions of the passage;

the improvement wherein a water-swellable composition is disposed on at least one of said surfaces, between said regions so as to predeterminedly constrain, by swelling, liquid flow within said passage between said regions to a reduced, non-zero rate.

11. A bridge as defined in claim 9, wherein said composition swells at a rate such that there is a reduction of about 50% in said initial capillary spacing by the time the liquid has traveled said one-half distance.

12. In an ion bridge fluidly connecting at least two ion-selective electrodes comprising the reagents operative to provide a determination of the activity of an ionic analyte in a liquid having a surface tension between about 25 and about 75 dynes/cm², said bridge comprising

two opposed liquid transport surfaces spaced apart a distance effective to induce capillary flow between said surfaces of introduced liquid and to create a transport passage, said passage having portions that are in separate liquid communication with each of said electrodes;

access means, including two apertures, for admitting liquids to said passage from the exterior of said bridge, a portion of said passage between said apertures being constructed to bring together at a junction two such liquids introduced to said passage each through a respective separate one of said apertures,

the improvement wherein a water-swellable composition is disposed on at least one of said surfaces, between said apertures to form an initial capillary spacing between said composition and the other of said surfaces,

said passage between said apertures having a predetermined length and said composition being water-swellable by an amount and at a predetermined rate such that said initial capillary spacing is reduced by at least about 25% by the time liquid introduced into one of said apertures flows to said junction.

13. A bridge as defined in claim 9 or 12, wherein said passage portions providing liquid communication with said each electrode include means in said surfaces defining a diverting aperture terminated by one of said electrodes, said composition being disposed on at least that part of one of said surfaces that is opposite to said diverting aperture,

whereby said composition of said passage portion, when contacted with an aqueous liquid, acts to drive the liquid towards the respective electrode.

14. A bridge as defined in claim 9 or 12, wherein said passage portions providing liquid communication with said each electrode are characterized by a spaced-apart distance having a value that increases with increased liquid-flow distance from said access aperture, said composition being disposed on at least one of said surfaces that provides said increasing spaced-apart distance.

15. A bridge as defined in claim 9 or 12, wherein said composition comprises a material selected from the group consisting of gelatin, a gelatin derivative, starch, polysaccharide, hydrogel, gum arabic, agarose, zein, casein, pectin, a derivative of collagen, collodion, agar-agar, arrowroot, polyvinyl alcohol, polyvinylpyrrolidone, a cellulose derivative, and a mixture of any of said materials.

16. A bridge as defined in claim 15, and further including a surfactant admixed with said material.

17. A bridge as defined in claim 9 or 12, wherein, over a period of about 3 minutes, said composition is swellable by an amount no greater than that which reduces the volume of said passage in the vicinity of said composition, by 50%,

whereby whole blood is capable of flowing within said passage without being blocked by composition swell.

18. In a liquid transport device for simultaneously transporting two different aqueous liquids within a capillary passage, said device comprising two opposed liquid transport surfaces spaced apart a distance effective to induce capillary flow between said surfaces of introduced liquid and to create the capillary passage;

and access means, including two apertures, for respectively admitting said different liquids to said passage from the exterior of the device to two spaced-apart regions of the passage;

the improvement wherein there is disposed on at least one of said surfaces, spaced a capillary distance from the other surface, control means for (a) increasing the viscosity of the liquid while it is flowing past said at least one surface, and (b) at the same time maintaining such flow continuous within said passage, said control means being effective to increase said viscosity during liquid flow by at least an amount sufficient, over a time period of about 3 minutes, to prevent displacement of the junction formed between two liquids, having a difference in surface tension of about 4 dynes/cm, that are introduced into said passage via said apertures.

19. A device as defined in claim 18, wherein said control means comprises a water-swellable composition disposed on said at least one surface.

20. In an ion bridge fluidly connecting at least two ion-selective electrodes comprising the reagents operative to provide a determination of the activity of an ionic analyte in a liquid having a surface tension between about 25 and about 75 dynes/cm², said bridge comprising

two opposed liquid transport surfaces spaced apart a distance effective to induce capillary flow between said surfaces of introduced liquid and to create a transport passage, said passage having portions that are in separate liquid communication with each of said electrodes;

and access means, including two apertures, for respectively admitting liquids from the exterior of said bridge to two spaced-apart regions of the passage;

the improvement wherein there is disposed on at least one of said surfaces, spaced a capillary distance from the other surface, control means for (a) increasing the viscosity of the liquid while it is flowing past said at least one surface, and (b) at the same time maintaining such flow continuous within said passage, said control means being effective to increase said viscosity during liquid flow by at least an amount sufficient, over a time period of about 3 minutes, to prevent displacement of the junction formed between two liquids, having a difference in surface tension of about 4 dynes/cm, that are introduced into said passage via said apertures.

21. A bridge as defined in claim 20, wherein said control means comprises a water-swellable composition disposed on said at least one surface.