Electrode with improved signal to noise ratio
First Claim
1. A method of measuring the amount or concentration of a chemical signal in a mammalian subject, the method comprising the steps of:
- contacting the skin of the mammalian subject with a first surface of a hydrogel medium through which a chemical signal can diffuse in response to a current, said hydrogel comprising water, electrolyte, and an enzyme, wherein the thickness of said hydrogel is in the range of 10 μ
m to 1,000 μ
m;
contacting an electrode assembly to a second surface of the medium, the assembly comprising a working electrode comprised of a plurality of substantially physically separated electrode surfaces and an electroosmotic electrode, wherein (i) the working electrode surfaces are separated by a gap having a width in a range of 10 μ
m to 1,000 μ
m, (ii) an electrically insulating material is positioned in each gap separating the electrode surfaces, (iii) the working electrode is characterized by a substantially planar configuration, and (iv) the working electrode has a thickness in a range of 0.25 μ
m to 250 μ
m;
providing current to the electroosmotic electrode sufficient to create diffusion of a chemical signal across the mammalian subject'"'"'s skin, through the medium and to the working electrode in a first dimension direction and a second dimension direction;
providing a voltage to each of the working electrode surfaces of the working electrode sufficient to drive electrochemical detection of chemical signal which generates an electrical current at the working electrode surfaces, wherein said electrical current is generated at the working electrode surfaces by electrochemical oxidation of hydrogen peroxide producing an electrical signal;
measuring the electrical current generated at the working electrode surfaces; and
correlating the measured current to the amount or concentration of chemical signal in the mammalian subject.
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Accused Products
Abstract
An electrode assembly for sensing an electrochemical signal diffused from a source to a working electrode which is comprised of a plurality of substantially separated working electrode surfaces is disclosed. The electrode of the invention is comprised of 1) a working electrode made up of a plurality of working electrode surfaces or components and 2) a electrically insulating gap defined by adjacent edges of 1) insulating the working electrode surfaces or components from each other. The working electrode components are configured to receive electrochemical signal from two or preferably three dimensions simultaneously. The working electrode components configured over the same surface as a single electrode provide (1) an improved signal to noise ratio as compared to a single electrode by reducing noise, and (2) provide an overall enhanced signal after sensing for a given period of time.
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Citations
24 Claims
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1. A method of measuring the amount or concentration of a chemical signal in a mammalian subject, the method comprising the steps of:
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contacting the skin of the mammalian subject with a first surface of a hydrogel medium through which a chemical signal can diffuse in response to a current, said hydrogel comprising water, electrolyte, and an enzyme, wherein the thickness of said hydrogel is in the range of 10 μ
m to 1,000 μ
m;contacting an electrode assembly to a second surface of the medium, the assembly comprising a working electrode comprised of a plurality of substantially physically separated electrode surfaces and an electroosmotic electrode, wherein (i) the working electrode surfaces are separated by a gap having a width in a range of 10 μ
m to 1,000 μ
m, (ii) an electrically insulating material is positioned in each gap separating the electrode surfaces, (iii) the working electrode is characterized by a substantially planar configuration, and (iv) the working electrode has a thickness in a range of 0.25 μ
m to 250 μ
m;providing current to the electroosmotic electrode sufficient to create diffusion of a chemical signal across the mammalian subject'"'"'s skin, through the medium and to the working electrode in a first dimension direction and a second dimension direction; providing a voltage to each of the working electrode surfaces of the working electrode sufficient to drive electrochemical detection of chemical signal which generates an electrical current at the working electrode surfaces, wherein said electrical current is generated at the working electrode surfaces by electrochemical oxidation of hydrogen peroxide producing an electrical signal; measuring the electrical current generated at the working electrode surfaces; and correlating the measured current to the amount or concentration of chemical signal in the mammalian subject. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method of measuring the amount or concentration of glucose in a human patient, comprising the steps of:
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contacting the skin of the patient with a first surface of a hydrogel medium through which glucose diffuses, said hydrogel comprising water, electrolyte and glucose oxidase, wherein (i) glucose oxidase catalyzes a reaction resulting in conversion of glucose to gluconic acid, (ii) the thickness of said hydrogel is in the range of 10 μ
m to 1,000 μ
m;contacting an electrode assembly to a second surface of the hydrogel medium, the assembly comprising a working electrode comprised of a plurality of substantially physically separated working electrode planar surfaces and an electroosmotic electrode, wherein (i) the working electrode surfaces are separated by a gap having a width in a range of 10 μ
m to 1,000 μ
m, (ii) an electrically insulating material is positioned in each gap separating the electrode surfaces, (iii) the working electrode is characterized by a substantially planar configuration, and (iv) the working electrode has a thickness in a range of 0.25 μ
m to 250 μ
m;providing current to the electroosmotic electrode sufficient to draw ions through the skin of the patient along with glucose wherein the working electrode planar surfaces are configured such that the glucose is drawn in a first direction normal to the planar surfaces and in a second direction substantially parallel to the planar surfaces; providing a voltage to each of the working electrode surfaces sufficient to drive electrochemical detection of a product of the reaction of glucose and glucose oxidase which generates an electrical current at the working electrode surfaces; measuring the electrical current at the working electrode surfaces; and correlating the measured current to the amount or concentration of glucose in the patient. - View Dependent Claims (13)
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14. A hydrogel and electrode assembly for use in a glucose monitoring device, comprising:
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a hydrogel comprised of water, electrolyte and glucose oxidase, wherein (a) glucose oxidase catalyzes a reaction resulting in conversion of glucose to gluconic acid, and (b) the thickness of said hydrogel is in the range of 10 μ
m to 1,000 μ
m; andan electrode assembly comprising a working electrode that comprises a plurality of substantially physically separated working electrode planar surfaces, wherein (i) each working electrode surface comprises a catalytic surface and is separated from adjacent working electrode surfaces by a gap, said gap having a width in a range of 10 μ
m to 1,000 μ
m, (ii) an electrically insulating material is positioned in each gap separating the electrode surfaces, (iii) the working electrode is characterized by a substantially planar configuration, (iv) the working electrode has a thickness in a range of 0.25 μ
m to 250 μ
m, and v) a voltage may be provided to each of the working electrode surfaces sufficient to drive electrochemical detection of a product of the reaction of glucose and glucose oxidase which generates an electrical current at the working electrode surfaces. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22)
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23. A method of measuring the amount or concentration of a chemical signal in a mammalian subject, the method comprising the steps of:
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contacting a first surface of an ionically conductive hydrogel with a skin surface of the mammalian subject, said hydrogel comprising water, electrolyte, and an enzyme, wherein the thickness of said hydrogel is in the range of 10 μ
m to 1,000 μ
m;contacting an electrode assembly to a second surface of the hydrogel, the assembly comprising an electroosmotic electrode, a working electrode comprised of a plurality of substantially physically separated working electrode planar surfaces, a counter electrode, and a reference electrode, wherein (i) the working electrode surfaces are separated by a gap having a width in a range of 10 μ
m to 1,000 μ
m, (ii) an electrically insulating material is positioned in each gap separating the electrode surfaces, (iii) the working electrode is characterized by a substantially planar configuration, and (iv) the working electrode has a thickness in a range of 0.25 μ
m to 250 μ
m;providing current to the electroosmotic electrode sufficient to draw the chemical signal across the mammalian subject'"'"'s skin, through the hydrogel and to the working electrode; providing a voltage to the working electrode planar surfaces sufficient to drive electrochemical detection of chemical signal which generates an electrical current at the working electrode surfaces, wherein said electrical current is generated at the working electrode surfaces by electrochemical oxidation of hydrogen peroxide producing an electrical signal; measuring the electrical current generated at the working electrode; and correlating the measured current to the amount or concentration of chemical signal in the mammalian subject.
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24. A method of measuring the amount or concentration of glucose in a mammalian subject, the method comprising the steps of:
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contacting a first surface of an ionically conductive hydrogel with a skin surface of the mammalian subject, said hydrogel comprising water, electrolyte and glucose oxidase, wherein (i) glucose oxidase catalyzes a reaction resulting in conversion of glucose to gluconic acid, and (ii) the thickness of said hydrogel is in the range of 10 μ
m to 1,000 μ
m;contacting an electrode assembly to a second surface of the hydrogel, the assembly comprising an electroosmotic electrode, a working electrode comprised of a plurality of substantially physically separated working electrode planar surfaces, a counter electrode, and a reference electrode, wherein (i) the working electrode surfaces are separated by a gap having a width in a range of 10 μ
m to 1,000 μ
m, (ii) an electrically insulating material is positioned in each gap separating the electrode surfaces, (iii) the working electrode is characterized by a substantially planar configuration, and (iv) the working electrode has a thickness in a range of 0.25 μ
m to 250 μ
m;providing current to the electroosmotic electrode sufficient to draw the glucose across the mammalian subject'"'"'s skin and into the hydrogel; providing a voltage to the working electrode planar surfaces sufficient to drive electrochemical detection of a product of the reaction of glucose and glucose oxidase which generates an electrical current at the working electrode surfaces; measuring the electrical current generated at the working electrode; and correlating the measured current to the amount or concentration of glucose in the mammalian subject.
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Specification