Microelectrodes in an ophthalmic electrochemical sensor
First Claim
1. An eye-mountable device, comprising:
- a transparent polymeric material having a concave surface and a convex surface, wherein the concave surface is configured to be removably mounted over a corneal surface and the convex surface is configured to be compatible with eyelid motion when the concave surface is so mounted, and wherein the transparent polymeric material includes a thinned region that defines an indentation in at least one of the concave or convex surfaces;
a substrate at least partially embedded within the polymeric material;
an antenna disposed on the substrate;
a two-electrode electrochemical sensor disposed on a surface of the substrate and including;
a working electrode having a width dimension equal to or less than 25 micrometers, wherein the width dimension is substantially parallel to the surface of the substrate; and
a reference electrode having an area at least five times greater than an area of the working electrode; and
a controller electrically connected to the electrochemical sensor and the antenna, wherein the controller is configured to;
(i) apply a voltage between the working electrode and the reference electrode sufficient to generate an amperometric current related to the concentration of an analyte in a fluid to which the eye-mountable device is exposed;
(ii) measure the amperometric current; and
(iii) use the antenna to indicate the measured amperometric current,wherein the working electrode and the reference electrode are disposed within the transparent polymeric material beneath the thinned region such that an electrical current conveyed between the working electrode and the reference electrode is passed through the thinned region of the transparent polymeric material.
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Accused Products
Abstract
An eye-mountable device includes an electrochemical sensor embedded in a polymeric material configured for mounting to a surface of an eye. The electrochemical sensor includes a working electrode, a reference electrode, and a reagent that selectively reacts with an analyte to generate a sensor measurement related to a concentration of the analyte in a fluid to which the eye-mountable device is exposed. The working electrode can have at least one dimension less than 25 micrometers. The reference electrode can have an area at least five times greater than an area of the working electrode. A portion of the polymeric material can surround the working electrode and the reference electrode such that an electrical current conveyed between the working electrode and the reference electrode is passed through the at least partially surrounding portion of the transparent polymeric material.
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Citations
20 Claims
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1. An eye-mountable device, comprising:
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a transparent polymeric material having a concave surface and a convex surface, wherein the concave surface is configured to be removably mounted over a corneal surface and the convex surface is configured to be compatible with eyelid motion when the concave surface is so mounted, and wherein the transparent polymeric material includes a thinned region that defines an indentation in at least one of the concave or convex surfaces; a substrate at least partially embedded within the polymeric material; an antenna disposed on the substrate; a two-electrode electrochemical sensor disposed on a surface of the substrate and including; a working electrode having a width dimension equal to or less than 25 micrometers, wherein the width dimension is substantially parallel to the surface of the substrate; and a reference electrode having an area at least five times greater than an area of the working electrode; and a controller electrically connected to the electrochemical sensor and the antenna, wherein the controller is configured to;
(i) apply a voltage between the working electrode and the reference electrode sufficient to generate an amperometric current related to the concentration of an analyte in a fluid to which the eye-mountable device is exposed;
(ii) measure the amperometric current; and
(iii) use the antenna to indicate the measured amperometric current,wherein the working electrode and the reference electrode are disposed within the transparent polymeric material beneath the thinned region such that an electrical current conveyed between the working electrode and the reference electrode is passed through the thinned region of the transparent polymeric material. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A system comprising:
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an eye-mountable device including; a transparent polymeric material having a concave surface and a convex surface, wherein the concave surface is configured to be removably mounted over a corneal surface and the convex surface is configured to be compatible with eyelid motion when the concave surface is so mounted, and wherein the transparent polymeric material includes a thinned region that defines an indentation in at least one of the concave or convex surfaces; a substrate at least partially embedded within the polymeric material; an antenna disposed on the substrate; a two-electrode electrochemical sensor disposed on a surface of the substrate and including; a working electrode having a width dimension equal to or less than 25 micrometers, wherein the width dimension is substantially parallel to the surface of the substrate; and a reference electrode having an area at least five times greater than an area of the working electrode; and a controller electrically connected to the electrochemical sensor and the antenna, wherein the controller is configured to;
(i) apply a voltage between the working electrode and the reference electrode sufficient to generate an amperometric current related to the concentration of an analyte in a fluid to which the eye-mountable device is exposed;
(ii) measure the amperometric current; and
(iii) use the antenna to indicate the measured amperometric current,wherein the working electrode and the reference electrode are disposed within the transparent polymeric material beneath the thinned region such that an electrical current conveyed between the working electrode and the reference electrode is passed through the thinned region of the transparent polymeric material; and a reader including; one or more antennae configured to; transmit radio frequency radiation to power the eye-mountable device, and receive indications of the measured amperometric current via backscatter radiation received at the one or more antennae; and a processing system configured to determine a tear film analyte concentration value based on the backscatter radiation. - View Dependent Claims (14, 15, 16, 17, 18)
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19. A method comprising:
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applying a voltage between a working electrode and a reference electrode sufficient to cause electrochemical reactions at the working electrode, wherein the working electrode and the reference electrode are disposed on a surface of a substrate embedded within an eye-mountable device having a concave surface and a convex surface, wherein the concave surface is configured to be removably mounted over a corneal surface and the convex surface is configured to be compatible with eyelid motion when the concave surface is so mounted, wherein the eye-mountable device includes a thinned region that defines an indentation in at least one of the concave or convex surfaces, wherein the working electrode has a width dimension equal to or less than 25 micrometers, wherein the width dimension is substantially parallel to the surface of the substrate, wherein the reference electrode has an area at least five times greater than an area of the working electrode, and wherein the working electrode and the reference electrode are arranged in the eye-mountable device such that the electrochemical reactions are related to a concentration of an analyte in a fluid to which the eye-mountable device is exposed; while applying the voltage, measuring an amperometric current through the working electrode, wherein the working electrode and the reference electrode are disposed within the polymeric material of the eye-mountable device beneath the thinned region such that an electrical current conveyed between the working electrode and the reference electrode is passed through the thinned region of the polymeric material; and wirelesly indicating the measured amperometric current via an antenna embedded within the eye-mountable device. - View Dependent Claims (20)
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Specification