Device and Method for Detection of Analytes

• US 20080096189A1
• Filed: 11/23/2005
• Published: 04/24/2008
• Est. Priority Date: 11/24/2004
• Status: Active Grant

• Current Assignee: TECHLAB, Inc.
• Original Assignee: TECHLAB, Inc.
• Inventors: Boone, James, Lyerly, David, Wilkins, Tracy
• Granted Patent: US 8,343,726 B2
• Time in Patent Office: Days
• US Class Current: 435/5
• CPC Class Codes: G01N 2333/33 from Clostridium (G)
• CPC Class Codes: G01N 2333/79 Transferrins, e.g. lactoferrins, ovotransferrins
• CPC Class Codes: G01N 2333/906 acting on nitrogen containing compounds as donors (1.4, 1.5, 1.7)
• CPC Class Codes: G01N 2333/90611 with NAD or NADP as acceptor (1.4.1) in general
• CPC Class Codes: G01N 2333/90616 with a definite EC number (1.4.1.-)
• CPC Class Codes: G01N 2333/91097 Hexosyltransferases (general) (2.4.1)
• CPC Class Codes: G01N 33/54366 Apparatus specially adapted for solid-phase testing
• CPC Class Codes: G01N 33/573 for enzymes or isoenzymes
• CPC Class Codes: G01N 33/6803 General methods of protein analysis not limited to specific proteins or families of proteins
• CPC Class Codes: G01N 33/6845 Methods of identifying protein-protein interactions in protein mixtures

Abstract

The present invention provides assays and devices for detection of substances in liquid samples. The assays and devices utilize passive diffusion between a porous material and a porous membrane containing a specific binding pair member to enable detection of the substance of interest.

Claims

1. A method of detecting at least one substance of interest in a liquid sample, said method comprising:

providing a liquid sample comprising or suspected of comprising the substance(s) of interest;

applying the liquid sample to a porous material in a sufficient amount to at least partially wet the porous material;

contacting the porous material with a porous membrane comprising at least one specific binding pair member that is capable of binding, either directly or indirectly, the substance(s) of interest;

maintaining the porous material and porous membrane in contact for a sufficient amount of time for liquid present in the porous material to diffuse in, out, through, and/or about the porous membrane,

wherein diffusion of the liquid in, out, through, and/or about the porous membrane results in contact of the substance(s) of interest, if present, to be bound, either directly or indirectly, to the specific binding pair member(s); and

detecting the presence or absence of a complex comprising the specific binding pair member(s) and the substance(s) of interest,

wherein the presence of at least one complex indicates the presence of at least one of the substances of interest in the liquid sample.

2. The method of claim 1, further comprising:

providing a device comprising the porous material and porous membrane.

3. The method of claim 1, wherein the porous material filters the liquid sample to remove substances having a size greater than a pre-determined value.

4. The method of claim 3, wherein the filtering is by way of discontinuous wicking of liquid from the liquid sample through the porous material.

5. The method of claim 1, wherein the liquid comprises two or more substances of interest.

6. The method of claim 5, wherein each substance of interest is different than each other substance of interest.

7. The method of claim 5, wherein the liquid comprises feces, blood, food, or an environmental sample.

8. The method of claim 1, wherein the substance(s) of interest is Clostridium difficile toxin A, Clostridium difficile toxin B, or both.

9. The method of claim 1, wherein the substance(s) of interest is one or more toxin, bacteria, viruses, bacterial products, enzymes, or parasites.

10. The method of claim 1, wherein the substance(s) of interest is glutamate dehydrogenase.

11. The method of claim 1, wherein the substance is an animal or human product.

12. The method of claim 1, wherein the substance is an antibody or lactoferrin.

13. The method of claim 1, wherein one or more of the specific binding pair member(s) is an antibody, wherein each of the antibodies is either different or the same as one or more others.

14. The method of claim 1, further comprising washing the membrane prior to detecting the presence of the complex.

15. The method of claim 1, wherein applying the liquid sample to the porous material comprises applying the liquid sample at a location on the porous material that is spatially separated from the porous membrane, whereby at least the liquid of the liquid sample travels into the porous material and then the porous membrane.

16. The method of claim 15, wherein the liquid sample travels through the porous material to the porous membrane through a wicking process.

17. The method of claim 1, further comprising applying a physical force to the membrane, the porous material, or both.

18. The method of claim 1, wherein detecting comprises observing a signal emitted from a label bound to a substance of interest.

19. The method of claim 18, wherein the signal is produced by a colored precipitating product that forms in or around the specific binding pair member.

20. The method of claim 1, further comprising combining a labeled conjugate with the liquid sample prior to applying the liquid sample to the porous material.

21. The method of claim 20, wherein the labeled conjugate comprises a latex bead or other colored particle, a colloidal gold particle, or a reactive substance that binds to a substrate to create a detectable signal.

22. The method of claim 18, wherein the signal is a non-visual signal.

23. The method of claim 1, wherein the method detects one or more nucleic acids or wherein one or more nucleic acids are specific binding pair members.

24. A device for detecting at least one substance of interest in a liquid sample, the device comprising:

(a) a receptacle comprising a porous material for receiving the liquid sample,

wherein the porous material is capable of absorbing and transmitting at least a portion of the liquid sample, and

(b) a porous membrane that comprises a specific binding pair member that is specific for the substance of interest or a substance bound to the substance of interest,

wherein the receptacle and porous membrane are each shaped to permit the porous membrane to be in direct contact with the porous material over at least a portion of the porous membrane that comprises the specific binding pair member.

25. The device of claim 24, further comprising a container containing the receptacle.

26. The device of claim 24, further comprising a holder for the porous membrane.

27. The device of claim 24, further comprising a wash solution receiving pad.

28. The device of claim 24, further comprising a liquid sample application pad.

29. The device of claim 24, further comprising a filtration pad.

30. The device of claim 24, wherein the device comprises a container containing a reaction pad comprising the porous material and the porous membrane, the container comprising a holder for the porous membrane,

wherein the container causes pressure to be exerted on the porous membrane and/or the porous material such that at least a portion of the porous material is compressed.

31. The device of claim 30, wherein the pressure causes the porous membrane and the porous material to be in direct contact over at least a portion of the porous membrane.

32. The device of claim 30, wherein the pressure permits liquids to pass between the porous membrane and the porous material by passive diffusion.

33. A device for detecting at least one substance of interest in a liquid sample, the device comprising:

(a) a receptacle comprising a porous material for receiving the liquid sample,

wherein the porous material is capable of absorbing and transmitting at least a portion of the liquid sample, and

(b) a porous membrane that comprises a specific binding pair member that is specific for the substance of interest or a substance bound to the substance of interest,

wherein the receptacle and porous membrane are each shaped to permit the porous membrane to be in direct contact with the porous material over at least a portion of the porous membrane that comprises the specific binding pair member,

wherein the porous membrane and porous material are different elements having a different chemical constitution.

34. The device of claim 33, wherein the porous membrane and porous material are in physical contact such that liquid sample applied to the porous material diffuses in, out, through, and about the porous membrane.

35. The device of claim 33, wherein a physical contact between the porous membrane and porous material is created such that sensitivity of the device is improved.

36. The device of claim 33, wherein the porous material and porous membrane are configured in contact with each other such that the substance of interest does not need to traverse the porous membrane in a unidirectional manner for the device to detect the substance of interest.

37. The device of claim 33, wherein the porous material and porous membrane are in contact with each other in such a way to permit simple, non-directional diffusion of a liquid between the two to occur.

38. A device for detecting the presence or amount of a substance of interest in a liquid sample, the device comprising:

a sample receiving zone for receiving the liquid sample,

wherein the sample receiving zone is present on a porous material;

a sample filter zone for filtering the liquid sample received at the sample receiving zone,

wherein the sample filtering zone is present on a porous material;

a porous membrane comprising a specific binding pair member at a detection zone that specifically binds to the substance of interest or a substance bound to the substance of interest,

wherein the porous membrane is not the same element as any of the porous materials, and

wherein the porous material and porous membrane are in physical contact over at least an area comprising a portion of the detection zone, and

wherein the porous material and porous membrane are in physical contact in a configuration that permits liquid present in the liquid sample to diffuse in, out, through, and about the porous membrane in a substantially random, non-directional manner in an area comprising at least a portion of the detection zone.

39. The device of claim 38, further comprising a container that contains at least a portion of the porous material(s) and porous membrane.

40. The device of claim 39, further comprising a porous material comprising a wash solution receiving zone.

41. A device comprising:

a receptacle; and

a porous membrane comprising at least one specific binding pair member that specifically binds to at least one substance of interest or a substance bound to that substance;

wherein the receptacle comprises an application zone, a filtration zone, and a reaction zone; and

wherein the receptacle and the porous membrane are in physical contact over at least a portion of the porous membrane comprising the specific binding pair member(s) and at least a portion of the reaction zone.

42. The device of claim 41, further comprising a wash solution receiving pad in physical contact with either the receptacle or the porous membrane.

43. The device of claim 41, further comprising a wash solution receiving pad and a liquid-impermeable membrane,

wherein the wash solution receiving pad is adjacent the receptacle, and the liquid impermeable membrane is interposed between, and in physical contact with both of, the receptacle and wash solution receiving pad.

44. The device of claim 42, wherein removal of the impermeable membrane results in physical contact between at least a portion of the receptacle and wash solution receiving pads.