Electrochemical methods and devices for amending urine samples for immunosensor detection

• US 9,651,547 B2
• Filed: 03/12/2014
• Issued: 05/16/2017
• Est. Priority Date: 03/14/2013
• Status: Expired due to Fees

• Current Assignee: Abbott Point Of Care Incorporated (Abbott Laboratories)
• Original Assignee: Abbott Point Of Care Incorporated (Abbott Laboratories)
• Inventors: Collier, G. Bruce, Campbell, John Lewis Emerson, Di Tullio, Katrina
• Primary Examiner(s): Crawford, Erik B
• Application Number:
  US14/206,532
• Publication Number:
  US 20140273034A1
• Time in Patent Office: 1,161 Days
• Field of Search: None
• CPC Class Codes: C12Q 1/58 involving urea or urease
• CPC Class Codes: G01N 2800/347 Renal failures; Glomerular diseases; Tubulointerstitial diseases, e.g. nephritic syndrome, glomerulonephritis; Renovascular diseases, e.g. renal artery occlusion, nephropathy
• CPC Class Codes: G01N 33/54306 Solid-phase reaction mechanisms
• CPC Class Codes: G01N 33/5438 Electrodes
• CPC Class Codes: G01N 33/54393 Improving reaction conditions or stability, e.g. by coating or irradiation of surface, by reduction of non-specific binding, by promotion of specific binding
• CPC Class Codes: G01N 33/62 involving urea
• CPC Class Codes: G01N 33/6893 related to diseases not provided for elsewhere

Abstract

The present invention is directed to methods and devices for amending undiluted and partially diluted urine samples in a manner suitable for performing immunoassays for target analytes, for example NGAL. Generally, the urine sample is treated with reagents including at least one of buffer materials, water soluble proteins, urease, and other interferent mitigants. These reagents control the pH of the urine sample in a manner suitable for immuno-binding reactions and ameliorate interferences, particularly during the detection step.

Claims

1. A device configured to perform an immunoassay for a target analyte in an amended urine sample, the device comprising:

a first region comprising reagents for of amending a urine sample, wherein the reagents comprise a water soluble protein for blocking non-specific binding of immunoglobulins at a sensor and a buffer; and

a second region comprising;

(i) a capture molecule capable of binding to the target analyte bound to a conjugate molecule labeled with an enzyme to form an immunocomplex, and (ii) the sensor comprising at least one electrode configured to detect the immunocomplex and determine a concentration of the target analyte in the amended urine sample,

wherein the first region is configured to provide a dissolved concentration of the water soluble protein within the amended urine sample in a range of about 0.02 to 225 mg/mL; and

wherein the reagents further comprise a scavenger for reducing non-specific current generation from electroactive species at the at least one electrode.

2. The device of claim 1, wherein the water soluble protein is recombinant or non-recombinant human serum albumin, porcine serum albumin, castor bean albumin, salmon serum albumin, bovine serum albumin, or a mixture thereof.

3. The device of claim 1, wherein:

the buffer adjusts a pH of the urine sample to within a preselected range; and

the buffer is selected from the group consisting of;

glycine, 3-(N-morpholino) propanesulfonic acid (MOPS), tris(hydroxymethyl)aminomethane (Tris), tricine, acetate, borate, 2-(N-morpholino)ethanesulfonic acid (MES), and 2-[[1,3-dihydroxy-2-(hydroxymethyl)propan -2-yl]amino]ethanesulfonic acid (TES).

4. The device of claim 1, wherein:

the first region is located in a first conduit comprising a wall;

the first conduit is configured to receive the urine sample;

the reagents are located on a portion of the wall and dissolvable in the urine sample;

the second region is located in a second conduit of the device;

the first conduit is connected to the second conduit; and

the second conduit is configured to receive the target analyte bound to the conjugate molecule in the amended urine sample.

5. The device of claim 1, wherein the target analyte is neutrophil gelatinase-associated lipocalin (NGAL).

6. The device of claim 1, wherein the reagents further comprise urease for reducing a urea concentration of the urine sample below a preselected urea threshold.

7. The device of claim 6, wherein the reagents further comprise glutamine synthetase or any other urea cycle enzyme capable of consuming ammonium.

8. The device of claim 6, wherein the reagents further comprise a sequestering enzyme capable of reducing and sequestering excess phosphate below a preselected phosphate threshold.

9. The device of claim 8, wherein the sequestering enzyme is adenylate kinase.

10. The device of claim 8, wherein the immunocomplex is formed on or substantially near the at least one electrode and the enzyme is alkaline phosphatase.

11. The device of claim 10, wherein the preselected phosphate threshold is 1/10 a number of alkaline phosphatase molecules.

12. A device configured to perform an immunoassay for a target analyte in an amemded urine sample, the device comprising:

a first region comprising reagents for amending a urine sample, wherein the reagents comprise a water soluble protein for blocking non-specific binding of immunoglobulins at a sensor and a buffer;

a capture molecule capable of binding to the target analyte to form an immunocomplex;

a second region comprising the sensor comprising at least one electrode configured to detect the immunocomplex and determine a concentration of the target analyte in the amended urine sample; and

a third region comprising a limited wash solvent capable of being delivered to the second region to wash the amended urine sample from the second region,

wherein the first region is configured to provide a dissolved concentration of the water soluble protein within the amended urine sample in a range of about 0.02 to 225 mg/mL; and

wherein the reagents further comprise a scavenger for reducing non-specific current generation from electroactive species at the at least one electrode.

13. A device configured to perform an immunoassay for a target analyte in an amended urine sample, the device comprising:

a first region comprising reagents for amending a urine sample, wherein the reagents comprise a water soluble protein for blocking non-specific binding of immunoglobulins at a sensor and a buffer;

a capture molecule capable of binding to the target analyte to form an immunocomplex; and

a second region comprising the sensor comprising at least one electrode configured to detect the immunocomplex and determine a concentration of the target analyte in the amended urine sample,

wherein the first region is configured to provide a dissolved concentration of the water soluble protein within the amended urine sample in a range of about 0.02 to 225 mg/mL; and

wherein the reagents further comprise urease for reducing a urea concentration of the urine sample below a preselected urea threshold.

14. The device of claim 13, wherein the reagents further comprise glutamine synthetase or any other urea cycle enzyme capable of consuming ammonium.

15. The device of claim 13, wherein the reagents further comprise a sequestering enzyme capable of reducing and sequestering excess phosphate below a preselected phosphate threshold.

16. The device of claim 15, wherein the sequestering enzyme is adenylate kinase.

17. The device of claim 15, further comprising a conjugate molecule labeled with an enzyme capable of binding to the target analyte, wherein the capture molecule is capable of binding to the target analyte bound to the conjugate molecule labeled with the enzyme to form the immunocomplex, the immunocomplex is formed on or substantially near the at least one electrode, and the enzyme is alkaline phosphatase.

18. The device of claim 17, wherein the preselected phosphate threshold is 1/10 a number of alkaline phosphatase molecules.

19. A device configured to perform an immunoassay for a target analyte in an amended urine sample, the device comprising:

a first region comprising reagents for amending a urine sample, wherein the reagents comprise a water soluble protein for blocking non-specific binding of immunoglobulins at a sensor and a buffer;

a second region comprising the sensor comprising;

(i) a capture molecule capable of binding to the target analyte to form an immunocomplex, and (ii) at least one electrode configured to detect the immunocomplex and determine a concentration of the target analyte in the amended urine sample; and

a third region comprising a limited wash solvent capable of being delivered to the second region to wash the amended urine sample from the second region,

wherein the first region is configured to provide a dissolved concentration of the water soluble protein within the amended urine sample in a range of about 0.02 to 225 mg/mL; and

wherein the reagents further comprise urease for reducing a urea concentration of the urine sample below a preselected urea threshold.

20. The device of claim 19, wherein the reagents further comprise glutamine synthetase or any other urea cycle enzyme capable of consuming ammonium.

21. The device of claim 19, wherein the reagents further comprise a sequestering enzyme capable of reducing and sequestering excess phosphate below a preselected phosphate threshold.

22. The device of claim 21, wherein the sequestering enzyme is adenylate kinase.

23. The device of claim 21, further comprising a conjugate molecule labeled with an enzyme capable of binding to the target analyte, wherein the capture molecule is capable of binding to the target analyte bound to the conjugate molecule labeled with the enzyme to form the immunocomplex, the immunocomplex is formed on or substantially near the at least one electrode, and the enzyme is alkaline phosphatase.

24. The device of claim 23, wherein the preselected phosphate threshold is 1/10 a number of alkaline phosphatase molecules.