Flow control technique for assay devices

• US 20060246597A1
• Filed: 04/29/2005
• Published: 11/02/2006
• Est. Priority Date: 04/29/2005
• Status: Active Grant

• Current Assignee: Kimberly-Clark Worldwide Incorporated (Kimberly-Clark Corporation)
• Original Assignee: Kimberly-Clark Worldwide Incorporated (Kimberly-Clark Corporation)
• Inventors: Yang, Kaiyuan, Feaster, Shawn Ray
• Granted Patent: US 7,858,384 B2
• Time in Patent Office: Days
• US Class Current: 436/169
• CPC Class Codes: G01N 33/52 Use of compounds or compositions for colorimetric, spectrophotometric or fluorometric investigation, e.g. use of reagent paper and including single- and multilayer analytical elements immunological elements G01N33/54386; involving labelled immunochemicals G01N33/58; for haemoglobin or occult blood G01N33/72
• CPC Class Codes: G01N 33/54388 based on lateral flow
• CPC Class Codes: G01N 33/558 using diffusion or migration of antigen or antibody immunochromatographic test strips G01N33/54387

Abstract

A method for controlling fluid flow in an assay device that employs a membrane is provided. Specifically, one or more recessed regions are formed in the membrane by applying a solvent treatment thereto. The solvent treatment is selected based on its particular dissolving capacity for the material used to form the membrane. For example, an alcohol-based solvent, such as methanol, may be used as a solvent for nitrocellulose membranes. Upon contact with the solvent treatment, a recessed region is formed that may serve a variety of different functions relating to flow control. In one particular embodiment, the recessed region may function as a metering channel that is capable of delivering a controlled volume of the test sample to a detection zone upon initiation of the assay.

Claims

1. A method for forming an assay device, the method comprising:

applying a solvent treatment to a membrane, the solvent treatment having a sufficient dissolving capacity for the membrane so that at least one recessed region is formed therein; and

forming a detection zone on the membrane to facilitate detection of an analyte that is suspected to be present within a test sample.

2. The method of claim 1, wherein the solvent treatment comprises an active solvent.

3. The method of claim 2, wherein the solvent treatment further comprises a co-solvent selected from the group consisting of active solvents and latent solvents.

4. The method of claim 3, wherein the active solvent is present in the treatment composition in an amount greater than about 50 vol. %.

5. The method of claim 1, wherein the solvent treatment comprises a glycol, glycol ether, ether, alcohol, triglycerides, ketone, ester, amide, nitrile, sulfoxide, or sulfone.

6. The method of claim 1, wherein the solvent treatment comprises acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, butyl acetate, methoxy propyl acetate, methyl glycol ether, ethyl glycol ether, isopropyl glycol ether, methanol, or ethanol.

7. The method of claim 1, wherein the solvent treatment comprises methanol.

8. The method of claim 1, wherein the membrane is formed from a polymeric material selected from the group consisting of nitrocellulose, polyether sulfone, polyethylene, nylon, polyvinylidene fluoride, polyester, and polypropylene.

9. The method of claim 1, wherein the membrane is formed from nitrocellulose.

10. The method of claim 1, wherein the solvent treatment is applied by spraying, printing, using a pipette, air brushing, or metering with a dispensing pump.

11. The method of claim 1, wherein the solvent treatment is applied in an amount of from about 0.01 to about 10 microliters per centimeter in width of the membrane.

12. The method of claim 1, wherein the solvent treatment is applied in an amount of from about 0.5 to about 5 microliters per centimeter in width of the membrane.

13. The method of claim 1, wherein a plurality of discrete recessed regions are formed in the membrane.

14. The method of claim 1, wherein the recessed region is a metering channel having a width that is the same or substantially equal to the width of the membrane.

15. The method of claim 1, wherein the solvent treatment further comprises a hydrophilic wetting agent, an agglutinating agent, or combinations thereof.

16. The method of claim 1, wherein the detection zone is formed by immobilizing a receptive material on the membrane, the receptive material being capable of binding to detection probes or conjugates thereof.

17. The method of claim 1, wherein the detection zone is located downstream from the recessed region.

18. A method for determining the presence of an analyte within a test sample, the method comprising:

applying a solvent treatment to a membrane, the solvent treatment having a sufficient dissolving capacity for the membrane so that at least one recessed region is formed therein; and

thereafter, contacting the metering channel with the test sample.

19. The method of claim 18, wherein the solvent treatment comprises an active solvent.

20. The method of claim 18, wherein the solvent treatment comprises acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, butyl acetate, methoxy propyl acetate, methyl glycol ether, ethyl glycol ether, and isopropyl glycol ether, methanol, or ethanol.

21. The method of claim 18, wherein the solvent treatment comprises methanol.

22. The method of claim 18, wherein the membrane is formed from a polymeric material selected from the group consisting of nitrocellulose, polyether sulfone, polyethylene, nylon, polyvinylidene fluoride, polyester, and polypropylene.

23. The method of claim 18, wherein the membrane is formed from nitrocellulose.

24. The method of claim 18, wherein the metering channel has a width that is the same or substantially equal to the width of the membrane.

25. The method of claim 18, wherein the solvent treatment further comprises a wetting agent, an agglutinating agent, or combinations thereof.

26. The method of claim 18, wherein the test sample flows from the metering channel to a detection zone.

27. The method of claim 26, wherein the membrane defines the detection zone, and the detection zone is located downstream from the metering channel.

28. The method of claim 26, wherein a receptive material is immobilized on the membrane within the detection zone, the receptive material being capable of binding to detection probes or conjugates thereof.

29. The method of claim 26, further comprising placing a bridging member over the metering channel that is in fluid communication with the detection zone.

30. The method of claim 26, further comprising supplying a diluent to the membrane to facilitate flow of the test sample to the detection zone.

31. The method of claim 18, wherein the test sample is whole blood.

32. The method of claim 31, further comprising separating plasma, serum, or both from the whole blood for analysis.

33. The method of claim 18, wherein the volume of the test sample is from about 0.5 to about 25 microliters.

34. The method of claim 18, wherein the volume of the test sample is from about 1 to about 10 microliters.