Method and apparatus for electrochemical detection

Patent metadata

Field	Value
Publication number	US-9678070-B2
Application number	US-201514699063-A
Country	US
Kind code	B2
Filing date	Apr 29, 2015
Priority date	Apr 29, 2015
Publication date	Jun 13, 2017
Grant date	Jun 13, 2017

Abstract

The invention provides an apparatus and methods for the electrochemical detection and/or quantitation of an analyte in a sample, wherein the device comprises a substrate and a detector, wherein the substrate comprises a labeled binding agent, wherein the label is an enteric material particle that encapsulates a ferrocene methanol redox species.

First claim

What is claimed is:

1. A diagnostic lateral flow assay device for detection of analyte in a sample, the device comprising:
a substrate comprising:
a first region comprising labeled antibodies specific for the analyte deposited thereon, wherein the labels of the labeled antibodies comprise enteric material particles comprising a copolymer of methyl methacrylate and methacrylic acid with ferrocene methanol embedded therein;
a second region comprising avidin or antibodies specific for the analyte immobilized thereon and an enzyme deposited thereon, wherein the enzyme interacts with an enzyme substrate in or added to the sample during the detection process to cause the release of ferrocene methanol from enteric material particles bound in the second region; and

a detector comprising at least one electrode surface to detect released ferrocene methanol.

2. The device of claim 1 , wherein the enzyme substrate is naturally present in the sample.

3. The device of claim 1 , wherein the enzyme is urease.

4. The device of claim 1 , wherein the substrate comprises a material selected from the group consisting of cellulose, nitrocellulose, cellulose acetate, polyacrylamide, agarose polyacrylamide, copolymer, agarose, starch, nylon, nylon polyesters, dextran, cross-linked dextran, dextran acrylamide copolymer, cross-linked hydroxymethylmethacrylate, substituted cross-linked polystyrenes, polyvinylalcohol, wool, metal oxides, porous ceramics coated with hydrophilic organic polymers, and glass.

5. The device of claim 1 , wherein the labels of the labeled antibodies have a diameter of between 40 nm and 300 nm.

6. The device of claim 1 , wherein the at least one electrode surface is embedded in the substrate.

7. The device of claim 1 , wherein the at least one electrode surface is formed by one or more wires extending transversely through the substrate perpendicular to the major faces of the substrate.

8. The device of claim 1 , further comprising a current measurement circuit to convert the detection of the ferrocene methanol by the detector into a measurement indicative of concentration of analyte in the sample.

9. the device of claim 1 , wherein if avidin is immobilized in the second region the substrate further comprises a third region between the first and second regions, and wherein the third region comprises biotinylated antibodies specific for the analyte deposited thereon.

10. A method of making a lateral flow assay device comprising:
mixing an entric material comprising a copolymer of methyl methacrylate and methacrylic acid with ferrocene methanol in a solvent;
removing the solvent to form particles of the enteric material having ferrocene methanol embedded therein;
attaching antibodies to the particles to produce labeled antibodies;
depositing the labeled antibodies onto a first region of solid matrix; and
immobilizing avidin or antibodies specific for the analyte and depositing enzyme onto a second region of the solid matrix that reacts with an enzyme substrate in or added to an assay sample to release the embedded ferrocene methanol.

11. The method of claim 10 , if avidin is immobilized in the second region, further comprising attaching biotin to antibodies specific for the analyte to produce biotinylated antibodies, and depositing the biotinylated antibodies onto a third region of the solid matrix.

12. A lateral flow assay method for determining the presence and quantity of analyte in a urine sample, the method comprising:
applying urine to the first region of the device in claim 1 ;
solubilizing labeled antibodies at a first region of the substrate with the urine, wherein the label of the labeled antibodies comprises an enteric material particle comprising a copolymer of methyl methacrylate and methacrylic acid having ferrocene methanol embedded therein;
solubilizing urease at a second region of the substrate with the urine to react with urea in the urine to raise the pH and release ferrocene methanol into the urine from labeled antibodies bound at the second region of the substrate;
detecting the released ferrocene methanol at the second region of the substrate; and
determining the presence and amount of analyte in the sample based on the detected ferrocene methanol.

13. The method of claim 12 , wherein the labeled antibodies bind to a first epitope of hCG, wherein the method additionally comprises solubilizing biotinylated antibodies with the urine at a third region of the substrate between the first region and the second region, wherein the biotinylated antibodies bind to a second different epitope of the hCG than the labeled antibodies, and wherein the second region of the substrate has avidin deposited thereon.

14. The method of claim 12 , wherein the second region further comprises antibodies specific for the analyte immobilized thereon.

Assignees

• Church & Dwight Co Inc
• Church & Dwight Co Inc

Inventors

• Nazareth Albert R
• Li Shang
• Sanders Giles H W
• Cass Anthony Edward George
• Rehak Marian

Classifications

• G01N33/543

  with an insoluble carrier for immobilising immunochemicals · CPC title

• C12Q1/001

  Enzyme electrodes · CPC title

• G01N33/558 Primary

  using diffusion or migration of antigen or antibody {(immunochromatographic test strips G01N33/54387)} · CPC title

• C12Q1/58

  involving urea or urease · CPC title

• G01N2458/30

  Electrochemically active labels · CPC title