Membrane-based assay devices

• US 20040043511A1
• Filed: 08/27/2002
• Published: 03/04/2004
• Est. Priority Date: 08/27/2002
• Status: Active Grant

• Current Assignee: Kimberly-Clark Worldwide Incorporated (Kimberly-Clark Corporation)
• Original Assignee: Kimberly-Clark Worldwide Incorporated (Kimberly-Clark Corporation)
• Inventors: Song, Xuedong, Kaylor, Rosann
• Granted Patent: US 7,285,424 B2
• Time in Patent Office: Days
• US Class Current: 436/526
• CPC Class Codes: G01N 2021/6439 with indicators, stains, dyes, tags, labels, marks
• CPC Class Codes: G01N 21/274 Calibration, base line adjustment, drift correction
• CPC Class Codes: G01N 21/6408 with measurement of decay time, time resolved fluorescence
• CPC Class Codes: G01N 33/525 Multi-layer analytical elements
• CPC Class Codes: G01N 33/54326 Magnetic particles
• CPC Class Codes: G01N 33/558 using diffusion or migration of antigen or antibody immunochromatographic test strips G01N33/54387
• CPC Class Codes: G01N 33/582 with fluorescent label
• CPC Class Codes: Y10S 435/803 Physical recovery methods, e.g. chromatography, grinding
• CPC Class Codes: Y10S 435/805 Test papers
• CPC Class Codes: Y10S 435/97 Test strip or test slide
• CPC Class Codes: Y10S 436/80 Fluorescent dyes, e.g. rhodamine
• CPC Class Codes: Y10S 436/806 Electrical property or magnetic property
• CPC Class Codes: Y10S 436/824 Immunological separation techniques
• CPC Class Codes: Y10T 436/13 Tracers or tags

Abstract

A membrane-based assay device for detecting the presence or quantity of an analyte residing in a test sample is provided. The device utilizes a self-calibrated magnetic binding assay format (e.g., sandwich, competitive, etc.) that includes detection probes capable of generating a detection signal (e.g., fluorescent non-magnetic particles) and calibration probes capable of generating a calibration signal (e.g., fluorescent magnetic particles). The amount of the analyte within the test sample is proportional (e.g., directly or inversely) to the intensity of the detection signal calibrated by the intensity of the calibration signal. It has been discovered that the fluidics-based device of the present invention provides an accurate, inexpensive, and readily controllable method of determining the presence of an analyte in a test sample.

Claims

14. A lateral flow membrane-based assay device for detecting the presence or quantity of an analyte residing in a test sample, said device comprising:

a porous membrane in fluid communication with detection probes capable of generating a detection signal, fluorescent magnetic calibration probes capable of generating a calibration signal, and optionally non-fluorescent magnetic particles, said porous membrane defining a detection zone; and

a magnetic device positioned adjacent to said detection zone, wherein said magnetic device is capable of separating said detection probes and said calibration probes from a test sample applied to said porous membrane, wherein the amount of the analyte within the test sample is proportional to the intensity of the detection signal generated by said separated detection probes at the detection zone calibrated by the intensity of the calibration signal generated by said separated calibration probes at the detection zone.

15. A device as defined in claim 14, further comprising one or more conjugate pads in fluid communication with said porous membrane, said detection probes and said calibration probes being applied to said one or more conjugate pads.

16. A device as defined in claim 14, wherein said porous membrane is in fluid communication with a sampling pad to which the test sample is applied.

17. A device as defined in claim 14, further comprising a wicking pad in fluid communication with said porous membrane to facilitate the flow of the test sample therethrough.

18. A device as defined in claim 14, wherein said detection probes are fluorescent non-magnetic compounds.

19. A device as defined in claim 14, wherein said separated detection probes include complexes formed by said detection probes.

20. A device as defined in claim 14, wherein said separated calibration probes include complexes formed by said calibration probes.

21. A device as defined in claim 14, wherein the amount of the analyte within the test sample is proportional to the intensity of the detection signal generated by said separated detection probes at said detection zone divided by the intensity of the calibration signal generated by said separated calibration probes at said detection zone.

22. A method for detecting the presence or quantity of an analyte residing in a test sample, said method comprising:

i) providing a membrane-based device, said device comprising;

a) a porous membrane in fluid communication with detection probes capable of generating a detection signal and magnetic calibration probes capable of generating a calibration signal, said porous membrane defining a detection zone; and

b) a magnetic device positioned adjacent to said detection zone;

ii) contacting said detection probes and said calibration probes with the test sample to form a solution;

iii) separating said detection probes and said calibration probes from said solution at said detection zone using said magnetic device;

iv) exciting said separated detection probes and said separated calibration probes, wherein said excitation causes said separated detection probes to emit said detection signal and said separated calibration probes to emit said calibration signal;

v) measuring the intensity of the detection signal at a first emission wavelength and the intensity of the calibration signal at a second emission wavelength; and

vi) comparing the intensity of the detection signal to the calibration signal, wherein the amount of the analyte within the test sample is proportional to the intensity of the detection signal calibrated by the intensity of the calibration signal.

1. A membrane-based assay device for detecting the presence or quantity of an analyte residing in a test sample, said device comprising:

a porous membrane in fluid communication with detection probes capable of generating a detection signal and magnetic calibration probes capable of generating a calibration signal, said porous membrane defining a detection zone; and

a magnetic device positioned adjacent to said detection zone, wherein said magnetic device is capable of separating said detection probes and said calibration probes from a test sample applied to said porous membrane, wherein the amount of the analyte within the test sample is proportional to the intensity of the detection signal generated by said separated detection probes at the detection zone calibrated by the intensity of the calibration signal generated by said separated calibration probes at the detection zone.

2. A device as defined in claim 1, further comprising one or more conjugate pads in fluid communication with said porous membrane, said detection probes and said calibration probes being applied to said one or more conjugate pads.

3. A device as defined in claim 1, wherein said porous membrane is in fluid communication with a sampling pad to which the test sample is applied.

4. A device as defined in claim 1, further comprising a wicking pad in fluid communication with said porous membrane to facilitate the flow of the test sample therethrough.

5. A device as defined in claim 1, wherein said detection probes and said calibration probes are fluorescent compounds, chemiluminescent compounds, phosphorescent compounds, or combinations thereof.

6. A device as defined in claim 1, wherein said detection probes are fluorescent non-magnetic compounds.

7. A device as defined in claim 1, wherein said calibration probes are fluorescent magnetic particles.

8. A device as defined in claim 1, wherein said detection probes are capable of binding to the analyte.

9. A device as defined in claim 1, further comprising non-fluorescent magnetic particles.

10. A device as defined in claim 9, wherein said non-fluorescent magnetic particles are capable of binding to the analyte.

11. A device as defined in claim 1, wherein said separated detection probes include complexes formed by said detection probes.

12. A device as defined in claim 1, wherein said separated calibration probes include complexes formed by said calibration probes.

13. A device as defined in claim 1, wherein the amount of the analyte within the test sample is proportional to the intensity of the detection signal generated by said separated detection probes at said detection zone divided by the intensity of the calibration signal generated by said separated calibration probes at said detection zone.

23. A method as defined in claim 22, wherein said membrane-based device further comprises one or more conjugate pads in fluid communication with said porous membrane, said detection probes and said calibration probes being applied to said one or more conjugate pads.

24. A method as defined in claim 22, wherein said porous membrane is in fluid communication with a sampling pad to which the test sample is applied.

25. A method as defined in claim 22, further comprising a wicking pad in fluid communication with said porous membrane to facilitate the flow of the test sample therethrough.

26. A method as defined in claim 22, wherein said detection probes are non-magnetic.

27. A method as defined in claim 22, wherein said separated detection probes include complexes formed by said detection probes.

28. A method as defined in claim 27, wherein said complexes are formed with the analyte.

29. A method as defined in claim 28, wherein said complexes are formed with the analyte.

30. A method as defined in claim 22, wherein said first emission wavelength is different than said second emission wavelength.

31. A method as defined in claim 22, further comprising generating a calibration curve by plotting the intensity of the detection signal calibrated by the intensity of the calibration signal for a plurality of predetermined analyte concentrations.

32. A method as defined in claim 22, wherein said separated detection probes and said separated calibration probes are excited simultaneously.

33. A method as defined in claim 22, wherein said separated detection probes and said separated calibration probes are excited separately.

34. A method as defined in claim 22, wherein the intensity of the detection signal and the calibration signal are measured simultaneously.

35. A method as defined in claim 22, wherein the intensity of the detection signal and the calibration signal are measured separately.

36. A method as defined in claim 22, wherein said detection and calibration probes are chemiluminescent.

37. A method as defined in claim 22, wherein said detection and calibration probes are phosphorescent.

38. A method as defined in claim 22, wherein said detection and calibration probes are fluorescent.

39. A method as defined in claim 38, wherein a fluorescence reader is used to measure the intensity of said detection signal and said calibration signal.

40. A method as defined in claim 39, wherein said fluorescence reader uses time-resolved fluorescence spectroscopy to measure said detection and said calibration signals.

28-1. A method as defined in claim 22, wherein said separated calibration probes include complexes formed by said calibration probes.