Electrochemical methods and devices for amending urine samples for immunosensor detection

• US 9,488,663 B2
• Filed: 03/12/2014
• Issued: 11/08/2016
• Est. Priority Date: 03/14/2013
• Status: Active Grant

• Current Assignee: Abbott Point Of Care Incorporated (Abbott Laboratories)
• Original Assignee: Abbott Point Of Care Incorporated (Abbott Laboratories)
• Inventors: Di Tullio, Katrina, Collier, G. Bruce, Campbell, John Lewis Emerson
• Primary Examiner(s): Crawford, Erik B
• Application Number:
  US14/206,831
• Publication Number:
  US 20140273014A1
• Time in Patent Office: 972 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: C12Q 1/58 involving urea or urease
• CPC Class Codes: G01N 2333/47 Assays involving proteins of known structure or function as defined in the subgroups
• CPC Class Codes: G01N 2333/98 acting on amide bonds in linear amides (3.5.1)
• 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 33/54393 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 a urine sample, the device comprising:

a first region comprising reagents configured to amend the urine sample to remove or reduce a urea concentration in the urine sample below a preselected urea threshold, wherein the reagents comprise urease and a buffer; and

a second region comprising at least one electrode coated with a biolayer comprising an attached capture antibody configured to bind to the target analyte, which is different from that of the urea, wherein the second region is configured to determine a concentration of the target analyte in the amended urine sample,

wherein the first region is configured to provide a dissolved urease enzymatic activity within the amended urine sample in a range of about 10 to 10,000 IU/mL.

2. The device of claim 1, wherein the immunoassay is selected from the group consisting of a one-step immunoassay, a low wash immunoassay, and a homogenous immunoassay.

3. The device of claim 1, wherein:

the buffer is configured to adjust 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 reagents are a dissolvable solid matrix comprising a sugar and printed on the first region.

5. The device of claim 1, wherein the urine sample is undiluted.

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

7. The device of claim 1, wherein the target analyte is selected from the group consisting of:

human chorionic gonadotrophin, troponin I, troponin T, Chlamydia, Legionella, acetaminophen, amphetamines, methamphetamines, barbiturates, benzodiazepines, cocaine, methadone, opiates, phencyclidine, marijuana, and tricyclic antidepressants.

8. The device of claim 1, wherein the preselected urea threshold is 10 mM.

9. The device of claim 1, wherein the preselected urea threshold is 0.1 mM.

10. The device of claim 1, wherein the reagents further comprise glutamine synthetase or any other urea cycle enzyme configured to consume ammonium.

11. The device of claim 1, wherein:

the reagents further comprise a sequestering enzyme configured to reduce and sequester excess phosphate below a preselected phosphate threshold; and

the sequestering enzyme is adenylate kinase.

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

a first region comprising reagents configured to amend the urine sample to remove or reduce a urea concentration in the urine sample below a preselected urea threshold, wherein the reagents comprise urease and a buffer;

a second region comprising at least one electrode coated with a biolayer comprising an attached capture antibody configured to bind to the target analyte, which is different from that of the urea, wherein the second region is configured to determine a concentration of the target analyte in the amended urine sample; and

a third region configured to provide a limited wash solvent for the second region configured to wash the amended urine sample,

wherein the first region is configured to provide a dissolved urease enzymatic activity within the amended urine sample in a range of about 10 to 10,000 IU/ml.

13. The device of claim 12, wherein the limited wash is less than fifty times a volume of the amended urine sample and fewer than three independent sample additions of clean wash buffer.

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

a first region comprising reagents configured to amend the urine sample, wherein the reagents comprise urease and a buffer; and

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

wherein the first region is configured to provide a dissolved urease enzymatic activity within the amended urine sample in a range of about 10 to 10,000 IU/mL; and

wherein the reagents further comprise glutamine synthetase or any other urea cycle enzyme configured to consume ammonium.

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

a first region comprising reagents configured to amend the urine sample, wherein the reagents comprise urease and a buffer; and

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

wherein;

the first region is configured to provide a dissolved urease enzymatic activity within the amended urine sample in a range of about 10 to 10,000 IU/mL;

the reagents further comprise a sequestering enzyme configured to reduce and sequester excess phosphate below a preselected phosphate threshold; and

the sequestering enzyme is adenylate kinase.

16. A device configured to perform an enzyme based immunoassay for a target analyte in a urine sample, the device comprising:

a first region comprising reagents configured to amend the urine sample, wherein the reagents comprise urease and a buffer;

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

a third region configured to provide a limited wash solvent for the second region configured to wash the amended urine sample,

wherein the first region is configured to provide a dissolved urease enzymatic activity within the amended urine sample in a range of about 10 to 10,000 IU/ml; and

wherein the reagents further comprise glutamine synthetase or any other urea cycle enzyme configured to consume ammonium.

17. A device configured to perform an enzyme based immunoassay for a target analyte in a urine sample, the device comprising:

a first region comprising reagents configured to amend the urine sample, wherein the reagents comprise urease and a buffer;

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

a third region configured to provide a limited wash solvent for the second region configured to wash the amended urine sample,

wherein;

the first region is configured to provide a dissolved urease enzymatic activity within the amended urine sample in a range of about 10 to 10,000 IU/mL;

the reagents further comprise a sequestering enzyme configured to reduce and sequester excess phosphate below a preselected phosphate threshold; and

the sequestering enzyme is adenylate kinase.