Test strip for lateral flow assays

• US 20080038759A1
• Filed: 08/10/2006
• Published: 02/14/2008
• Est. Priority Date: 08/10/2006
• Status: Active Grant

• Current Assignee: Inverness Medical Switzerland GmbH (Abbott Laboratories Incorporated)
• Original Assignee: Inverness Medical Switzerland GmbH (Abbott Laboratories Incorporated)
• Inventors: Keren, Tomer, Dwir, Oren Shraga
• Granted Patent: US 7,704,702 B2
• Time in Patent Office: Days
• US Class Current: 435/7.92
• CPC Class Codes: G01N 33/525 Multi-layer analytical elements
• 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 436/808 Automated or kit
• CPC Class Codes: Y10S 436/81 Tube, bottle, or dipstick

Abstract

A test strip configured for the detection of an analyte in a fluid sample and methods for manufacturing and for using the same. The test strip comprises a first flow matrix and a second flow matrix sequentially arranged to form an interface therebetween. The first flow matrix comprises a detection composition movably bound thereto, wherein the detection composition when exposed to the analyte produces at least one detectable product and wherein the first and second solid matrices are selected so as to accumulate the at least one detectable product at the interface between the two matrices, when the fluid sample travels from the first flow matrix to the second flow matrix.

Claims

1. A test strip configured for the detection of an analyte in a fluid sample, the strip comprising a first flow matrix and a second flow matrix sequentially arranged to form an interface therebetween, said first flow matrix comprises a detection composition movably bound thereto, wherein the detection composition in the presence of the analyte produces at least one detectable product and wherein the first and second solid matrices are selected so as to accumulate said at least one detectable product at said interface when the fluid sample travels from the first flow matrix to the second flow matrix.

2. The strip of claim 1 wherein at least one component of said detection composition is deposited on said first matrix in a re-dissolvable dry form.

3. The strip of claim 1 wherein said first matrix is of higher porosity than said second matrix.

4. The strip of claim 1 wherein the transport rate of said at least one detectable product through the first matrix is higher than the transport rate of said at least one detectable product through the second matrix.

5. The strip of claim 1 wherein the first matrix is a glass fiber or a filter paper and wherein the second matrix is a nitrocellulose or a nylon membrane.

6. The strip of claim 1 wherein said at least one product is insoluble in the sample fluid.

7. The strip of claim 1 wherein said detection composition is dissolvable in the sample fluid.

8. The strip of claim 1 wherein said first and second matrices are sandwiched between a backing and a top impermeable laminates.

9. The strip of claim 8 wherein at least one of said backing and top laminate is transparent or translucent.

10. The strip of claim 1 wherein said analyte is an enzyme and wherein said detection composition comprises a chromogenic substrate reagent system specific to said enzyme.

19. A method for detecting an analyte in a fluid sample, the method comprising the steps of:

providing the test device as defined in claim 1;

exposing said test device to said fluid sample; and

observing appearance of a color change;

wherein appearance of a distinguished color change indicates presence of the analyte in said fluid sample.

11. A strip for the detection of an enzyme in a fluid sample, the strip comprising a first matrix and a second matrix sequentially arranged on a non-absorbing solid support forming a junction therebetween, wherein the first matrix is provided with a movably bound enzyme detection composition,

the composition comprises a combination of components which upon exposure to said enzyme produces at least one detectable product;

and

wherein said first and second matrices are selected so as to accumulate said at least one detectable product at said junction when the fluid sample travels from the first flow matrix to the second flow matrix.

12. The strip of claim 11 wherein said detectable product is insoluble in the sample fluid.

13. The strip of claim 11 wherein said enzyme detection composition comprises a chromogenic substrate of said enzyme.

14. The strip of claim 13 wherein said enzyme detection composition further comprises a color intensifier.

15. The strip of claim 13 wherein said substrate comprises an indoxyl group.

16. The strip of claim 15 wherein the enzyme detection composition further comprises a tetrazolium salt.

17. The strip of claim 11 wherein said enzyme detection composition comprises a substrate of said enzyme and a chromogenic reagent, wherein said chromogenic reagent yields a detectable colored product in the presence of enzymatic reaction between the enzyme and the enzyme substrate.

18. The strip of claim 17 wherein said chromogen reagent is an electron donor or an electron acceptor.

20. A method for fabricating a test device adapted for the detection of an analyte in a fluid sample, the method comprising the steps of:

selecting a detection composition for the detection of said analyte, said detection composition is selected so as to produce at least one detectable product upon exposure to said analyte;

selecting a first and a second flow matrices of different characteristics, said first and second flow matrices are selected so as retain said at least one detectable product at an interface between said first and second matrices when said sample travels from the first matrix to the second matrix;

arranging said first and second matrices in a sequential order on a non-absorbing support so as to form an interface therebetween; and

providing the first matrix with a predetermined amount of said detection composition.