Multiple layer gel

• US 10,281,425 B2
• Filed: 05/18/2016
• Issued: 05/07/2019
• Est. Priority Date: 04/19/2012
• Status: Active Grant

• Current Assignee: Caerus Biotechnologies
• Original Assignee: Aytu Bioscience, Inc.
• Inventors: Bar-Or, Raphael, Bar-Or, David, Rael, Leonard T.
• Primary Examiner(s): Bowman, Andrew J
• Application Number:
  US15/157,538
• Publication Number:
  US 20160341693A1
• Time in Patent Office: 1,084 Days
• Field of Search: 20440304, 435 792, 427 21
• CPC Class Codes: G01N 27/301 Reference electrodes
• CPC Class Codes: G01N 27/3272 Test elements therefor, i.e. disposable laminated substrates with electrodes, reagent and channels optical biosensors G01N33/52
• CPC Class Codes: G01N 27/403 Cells and electrode assemblies
• CPC Class Codes: G01N 27/406 Cells and probes with solid electrolytes
• CPC Class Codes: G01N 27/4168 Oxidation-reduction potential, e.g. for chlorination of water water analysis G01N33/18
• CPC Class Codes: G01N 33/48707 by electrical means G01N33/49, G01N33/493 take precedence

Abstract

A multiple layer gel and method for forming a multiple layer gel are provided. The multiple layer gel includes an isolation layer and an electrolyte layer. The isolation layer provides a molecular weight screen, to prevent proteins or other molecules from contacting a reference cell covered by the isolation layer. The electrolyte layer covers the isolation layer, and provides a source of ions that place the reference cell in ionic and/or electrical contact with a fluid sample. The multiple layer gel can be used to maintain a reliable reference voltage from an associated reference cell while an electrical potential or other electrical characteristic of a sample fluid is being determined.

Claims

1. A method for forming a multiple layer gel on a test strip, comprising:

providing a test strip, wherein the test strip includes;

a substrate at least partially defining a sample chamber, and the substrate having a readout region;

a reference cell positioned on the substrate outside of the sample chamber;

a working electrode extending from the readout region of the substrate to the sample chamber;

a counter electrode extending from the readout region of the substrate to the sample chamber;

a reference electrode extending from the readout region of the substrate to the reference cell;

applying an isolation layer over the reference cell, wherein the isolation layer covers portions of the reference cell not in contact with a surface of the substrate or the reference electrode;

applying an electrolyte layer over the isolation layer; and

providing a bridge extending between the electrolyte layer and the sample chamber.

2. The method of claim 1, wherein applying an isolation layer includes applying a gel containing agarose and hydroxyethyl cellulose (HEC) over the reference cell.

3. The method of claim 2, wherein the isolation layer is applied using a heat block technique.

4. The method of claim 3, wherein applying an electrolyte layer includes applying a gel containing 3% HEC in 3M KCl over the isolation layer.

5. The method of claim 3, wherein after applying the isolation layer the test strip is allowed to dry at ambient temperature, and wherein after applying the electrolyte layer the test strip is placed in a pre-heated vacuum oven at 0.02 MPa below atmospheric pressure.

6. The method of claim 1, wherein applying an isolation layer includes applying a molecular screening layer.

7. The method of claim 1, wherein applying the electrolyte layer includes applying a source of chloride ions.

8. The method of claim 1, wherein applying the isolation layer includes applying an agarose and hydroxyethyl cellulose layer, and applying the electrolyte layer comprises applying an agarose and KCl layer.

9. The method of claim 1, wherein applying the isolation layer includes applying a water based gel containing about 4% agarose and about 1% hydroxyethyl cellulose, and applying the electrolyte layer comprises applying a water based gel containing about 4% agarose and about a 3M concentration of KCl.

10. The method of claim 1, wherein the isolation layer covers all portions of the reference cell that are not in contact with the surface of the substrate or the reference electrode.

11. A method for forming a multiple layer gel, comprising:

providing a test strip substrate that includes a plurality of test leads and a reference cell;

applying an isolation layer over the reference cell, wherein applying an isolation layer includes applying a gel containing agarose and hydroxyethyl cellulose (HEC) over the reference cell, and wherein the isolation layer is applied using a heat block technique; and

applying an electrolyte layer over the isolation layer, wherein applying an electrolyte layer includes applying a gel containing 3% HEC in 3M KCl over the isolation layer.

12. A method for forming a multiple layer gel, comprising:

providing a test strip substrate that includes a plurality of test leads and a reference cell;

applying an isolation layer over the reference cell, wherein applying the isolation layer includes applying a water based gel containing about 4% agarose and about 1% hydroxyethyl cellulose; and

applying an electrolyte layer over the isolation layer, wherein applying the electrolyte layer comprises applying a water based gel containing about 4% agarose and about a 3M concentration of KCl.