Diagnostic detection device and method

• US 20040171174A1
• Filed: 03/05/2004
• Published: 09/02/2004
• Est. Priority Date: 05/02/1995
• Status: Active Grant

• Current Assignee: Church & Dwight Company Incorporated
• Original Assignee: Church & Dwight Company Incorporated
• Inventors: Nazareth, Albert, Boyle, Mary Beth, Cheng, Yea-Shun
• Granted Patent: US 7,045,342 B2
• Time in Patent Office: Days
• US Class Current: 436/514
• 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
• CPC Class Codes: Y10S 435/805 Test papers
• CPC Class Codes: Y10S 435/81 Packaged device or kit
• CPC Class Codes: Y10S 435/97 Test strip or test slide
• CPC Class Codes: Y10S 436/81 Tube, bottle, or dipstick

Abstract

The invention provides an improved test cell for detecting the presence of an analyte in a liquid sample. The device has an elongate casing defining a liquid sample inlet, a reservoir volume, a test volume, and a window through the casing at the test volume. Disposed within the cell is a sample absorbent, a novel biphasic substrate and a reservoir, together capable of transporting an aqueous solution within the casing along a flow path extending from the sample inlet through the test volume and into the reservoir volume. The invention further comprises a method for detecting the presence of an analyte in a liquid sample using the device and a biphasic chromatographic material for carrying out the method.

Claims

1. A method for determining the presence in a liquid sample of an analyte comprising one member of a binding pair, said method comprising:

a. providing a biphasic substrate comprising a release medium near a proximal end of said substrate in liquid flow communication with capture medium located downstream of said release medium and near a distal end of said substrate, wherein said release and capture media together form a single liquid flow path, wherein, releasably disposed

on said release medium is

(i) a conjugate comprising a binding member reactive with a first epitope of said analyte labeled with a detectable marker; and

(ii) a capturable component which is reactive with a second epitope of the analyte thereby to form a complex of the binding member, the analyte and the capturable component; and

located on said capture material is

a capture site for capturing said complex, said capture site having immobilized by adsorption thereon a capture component having an affinity for said capturable component;

b. contacting said proximal end with a liquid sample such that the liquid flow sample travels by sorption along said liquid path to the distal end thereby inducing sequential reaction of the analyte with the binding member and the capturable component to form said complex, followed by reaction of the complex with the immobilized capture component; and

c. determining the presence of the analyte by observing the presence of the detectable marker at the capture site.

2. The method of claim 1 wherein said capturable component is disposed downstream of said conjugate on said release medium.

3. The method of claim 1 wherein said analyte is human chorionic gonadotropin.

4. The method of claim 1 wherein said analyte is luteinizing hormone.

5. The method of claim 1 wherein said release material is absorbent paper.

6. The method of claim 1 wherein said capture material is microporous nitrocellulose or nylon.

7. The method of claim 1 wherein said capture material is laminated to a transparent polymer layer.

8. The method of claim 1 wherein said detectable marker is a colored particle.

9. The method of claim 8 wherein said colored particle comprises gold sol particles.

10. The method of claim 1 wherein said capturable component is a biotinylated binding protein.

11. The method of claim 1 wherein said immobilized capture component is avidin.

12. The method of claim 1 wherein said capture material further comprises a control site located downstream of said capture site having immobilized thereon an agent which captures the conjugate.

13. A device for determining the presence in a liquid sample of an analyte comprising one member of a binding pair, wherein a liquid sample deposited at a proximal end of the device travels by sorption along a liquid path to a distal end of the device, said device comprising:

a. a biphasic substrate comprising a release medium near the proximal end of said device in liquid communication with a capture material located downstream of said release medium and near the distal end of said device, wherein located on said release medium of said substrate is

(i) a conjugate comprising a binding member reactive with a first epitope of said analyte labeled with a detectable marker; and

(ii) a capturable component which is reactive with a second epitope of the analyte thereby to form a complex of the binding member, the analyte and the capturable component; and

located on said capture material of said substrate is

a capture site for capturing said complex, said capture site having immobilized thereon a capture component having an affinity for said capturable component.

14. The device of claim 13 wherein said release material comprises absorbent paper and said capture material comprises microporous nitrocellulose or nylon.

15. The device of claim 13 further comprising a control site located downstream of said capture site on said capture material, said control site having immobilized thereon an agent which captures said conjugate.

16. The device of claim 13 wherein said analyte is human chorionic gonadotropin.

17. The device of claim 13 wherein said analyte is luteinizing hormone.

18. The device of claim 13 wherein said capturable component is a biotinylated antibody.

19. The device of claim 13 wherein said immobilized capture component comprises avidin or an antibiotin antibody.

20. The device of claim 13 wherein said capturable component is disposed downstream of said conjugate on said release medium.

21. The device of claim 13 further comprising a transparent, analyte-impermeable sheet material on a face of said capture material.

22. The device of claim 21 comprising a casing housing said substrate and defining a window near the distal end of said device to permit viewing of said capture site, and a liquid sample inlet near the proximal end of said device, said window and inlet being disposed on opposite sides of said casing.

23. A device for determining the presence in a liquid sample of an analyte comprising one member of a binding pair, wherein a liquid sample deposited on a proximal end of the device travels by capillary action along a liquid path to a distal end of the device, said device comprising:

a. a biphasic substrate comprising a release medium near the proximal end of said device in liquid communication with a capture medium located downstream of said release medium and near the distal end of said device;

wherein located on said release medium of said substrate is

(i) a conjugate comprising a binding member reactive with a first epitope of said analyte and labeled with a detectable marker; and

(ii) a capturable component located downstream of said binding member, which is reactive with a second epitope of the analyte thereby to form a complex of the binding member, the analyte and the capturable component; and

located on said capture material of said substrate is

a capture site for capturing said complex, said capture site having immobilized thereon a capture component having an affinity for said capturable component; and

b. a casing enclosing said substrate, said casing defining a sample inlet located at the proximal end of said device upstream of (i), and a detection opening located near the distal end of said device and positioned either opposite or on the same side as the capture site.

24. The device of claim 23 further comprising a control site located downstream of said capture site, said control site having immobilized thereon an agent capable of capturing said binding member.

25. The device of claim 24 wherein said casing further defines a control opening located downstream of the detection opening which control opening is positioned opposite said control site.

26. The device of claim 23 wherein said detection opening is located on a side of said casing opposite said sample inlet.

27. The device of claim 23 wherein said substrate element is in the shape of a flat sheet, and wherein said binding member, capturable component and capture site are located on a surface of said sheet.

28. The device of claim 23 wherein said release material is an absorbent paper and wherein said capture material is nitrocellulose or nylon.

29. The device of claim 23 wherein said capture material is laminated to or cast on a transparent polymeric material.

30. The device of claim 23 further comprising a sample absorbent located upstream of said substrate element at said proximal end of said device.

31. The device of claim 23 further comprising a residual absorbent located downstream of said substrate element at said distal end, which residual absorbent absorbs the liquid sample remaining after traversing said liquid path.

32. A method for producing a biphasic chromatographic substrate comprising:

a. providing a first phase comprising a release medium and a second phase comprising a capture medium;

b. joining said first and second phases by overlapping an end of said first phase and an end of said second phase such that said first and second phases form a single liquid flow path.

33. The method of claim 32 wherein said first phase is a hydrophilic porous material.

34. The method of claim 32 wherein said second phase is nitrocellulose or nylon.

35. The method of claim 32 wherein said second phase is laminated to or cast onto a transparent polymeric material.