# US 2014/0190839 A1 · Contact lenses having two-electrode electrochemical sensors > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0190839 A1 - Document ID: US20140190839A1 - Status: Published application - Kind: A1 - Application number: 13/568,078 - Filed: 2012-08-06 - Published: 2014-07-10 - Earliest claimed: 2012-08-06 - Assignees: Google Inc. - Inventors: Zenghe Liu - Web page: https://patentgrep.com/patent/US20140190839A1 ## CPC - A61B 5/1486: using enzyme electrodes, e.g. with immobilised oxidase - A61B 5/0004: {characterised by the type of physiological signal transmitted} - A61B 5/14507: {specially adapted for measuring characteristics of body fluids other than blood (devices for taking samples of body liquids A61B10/0045)} - A61B 5/14532: {for measuring glucose, e.g. by tissue impedance measurement} - A61B 5/6821: {Eye} - A61B 5/002: {Monitoring the patient using a local or closed circuit, e.g. in a room or building (A61B5/0017 takes precedence)} - A61B 5/14546: {for measuring analytes not otherwise provided for, e.g. ions, cytochromes} - A61B 5/1495: Calibrating or testing of in-vivo probes - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) ## Abstract Apparatus, systems and methods employing contact lenses with two-electrode electrochemical sensors are provided. In some aspects, the contact lens includes: a substrate that forms at least part of a body of the contact lens; and a circuit, disposed on or within the substrate, and including a two-electrode electrochemical sensor. The two-electrode electrochemical sensor can include: a working electrode; and a combination reference-counter electrode. The electrochemical sensor can be an amperometric sensor that senses a biological feature of a wearer of the contact lens. The working electrode can generate a signal indicative of the sensed analyte, and the combination reference-counter electrode can pass the signal generated from the working electrode. The signal can be employed to determine the analyte concentration of a solution in contact with the contact lens. ## Claims ### Claim 1 A contact lens, comprising: a substrate that forms at least part of a body of the contact lens; and a circuit, disposed on or within the substrate, and comprising a two-electrode electrochemical sensor, wherein the two-electrode electrochemical sensor comprises: a working electrode; and a combination reference-counter electrode. ### Claim 2 (depends on 1) The contact lens of claim 1, wherein the working electrode generates a signal indicative of a sensed analyte. ### Claim 3 (depends on 2) The contact lens of claim 2, wherein the combination reference-counter electrode passes the signal generated from the working electrode. ### Claim 4 (depends on 1) The contact lens of claim 1, wherein the working electrode and the combination reference-counter electrode are comprised of a same material. ### Claim 5 (depends on 1) The contact lens of claim 1, wherein the working electrode is comprised of platinum and the combination reference-counter electrode is comprised of a noble metal. ### Claim 6 (depends on 1) The contact lens of claim 1, wherein the combination reference-counter electrode is comprised of at least one of carbon or silver/silver chloride. ### Claim 7 (depends on 1) The contact lens of claim 1, wherein the two-electrode electrochemical sensor comprises a hydrogen peroxide sensor with two platinum electrodes. ### Claim 8 (depends on 1) The contact lens of claim 1, wherein the two-electrode electrochemical sensor is an amperometric sensor. ### Claim 9 (depends on 8) The contact lens of claim 8, wherein the amperometric sensor is a biosensor that senses a level of at least one of glucose, protein, triglycerides, urea or lactate in a body of a wearer of the contact lens. ### Claim 10 (depends on 8) The contact lens of claim 8, wherein the amperometric sensor comprises a working electrode having glucose oxidase deposited on the working electrode. ### Claim 11 (depends on 1) The contact lens of claim 1, wherein the working electrode is smaller than the combination reference-counter electrode. ### Claim 12 (depends on 11) The contact lens of claim 11, wherein a ratio of an area of the combination reference-counter electrode and an area of the working electrode is between 2 and 10000. ### Claim 13 A contact lens, comprising: a substrate that forms at least part of a body of the contact lens; and a circuit, disposed on or within the substrate, and comprising a two-electrode electrochemical sensor. ### Claim 14 (depends on 13) The contact lens of claim 13, wherein the two-electrode electrochemical sensor comprises a hydrogen peroxide sensor with two platinum electrodes. ### Claim 15 (depends on 13) The contact lens of claim 13, wherein the two-electrode electrochemical sensor is an amperometric sensor. ### Claim 16 (depends on 15) The contact lens of claim 15, wherein the amperometric sensor is a biosensor that senses at least one of glucose, protein, triglycerides, urea or lactate. ### Claim 17 (depends on 15) The contact lens of claim 15, wherein the amperometric sensor comprises a working electrode having glucose oxidase deposited on the working electrode. ### Claim 18 (depends on 13) The contact lens of claim 13, wherein components of the two-electrode electrochemical sensor are comprised of a same material. ### Claim 19 A method, comprising: determining a diffusion controlled region on a voltammogram; and determining a potential to be applied to a two-electrode electrochemical sensor of a contact lens, wherein the potential is substantially equivalent to a potential to be applied to a three-electrode electrochemical sensor of a contact lens, and the determining the potential being based on the diffusion controlled region. ### Claim 20 (depends on 19) The method of claim 19, wherein the determining the diffusion controlled region comprises performing one or more voltammetry experiments to determine the diffusion controlled region.