Electrode assembly for assaying glucose
First Claim
1. An electrode assembly for use in assaying glucose in a solution, the electrode assembly comprising:
- a sensor electrode; and
a membrane assembly overlaying the sensor electrode the membrane assembly includingan outer, diffusion-barrier layer positioned to contact the solution, the outer layer having a substantially uniform thickness and having a distribution of pores of a specific density and of a size in the range of 0.0125 to 0.0200 microns.an inner, interference-barrier layer contacting a face of the sensor electrode and having a substantially uniform thickness, wherein the inner layer includes a relatively thick, porous backing film and a relatively thin, porous overlaying film that overlays the backing film, andan immobilized glucose oxidase layer interposed between the outer and inner layers and having a substantially uniform thickness,wherein the outer layer is configured to allow glucose and oxygen to diffuse through it to reach the glucose oxidase layer, where the glucose and oxygen react to form reaction products that include hydrogen peroxide,and wherein the inner layer is configured to have a permeability sufficient to pass hydrogen peroxide from the glucose oxidase layer to the face of the sensor electrode.
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Accused Products
Abstract
An improved electrode assembly is disclosed for use in assaying glucose in solution, e.g., in undiluted whole blood. The assembly includes a sensor electrode and a special overlaying multi-layer membrane that can be sterilized by gamma radiation without reducing the activity of a glucose oxidase enzyme located in an intermediate layer of the membrane. An outer layer of the membrane is formed with microscopic pores having a predetermined density and predetermined size, for reliably controlling the flux of glucose and oxygen from the solution to the intermediate layer, where they react in the presence of the glucose oxidase enzyme to form reactions products that include hydrogen peroxide. The outer layer thus functions as a diffusion barrier, to eliminate the adverse effects of any oxygen deficit that might be present. In addition, an inner layer of the membrane functions as an interference barrier, for controlling the permeation of the hydrogen peroxide reaction product to the underlying electrode. The inner layer includes a relatively thick, porous backing film, formed for example of porous polyester, and a relatively thin, porous overlaying film, formed for example of polysulfone.
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Citations
17 Claims
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1. An electrode assembly for use in assaying glucose in a solution, the electrode assembly comprising:
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a sensor electrode; and a membrane assembly overlaying the sensor electrode the membrane assembly including an outer, diffusion-barrier layer positioned to contact the solution, the outer layer having a substantially uniform thickness and having a distribution of pores of a specific density and of a size in the range of 0.0125 to 0.0200 microns. an inner, interference-barrier layer contacting a face of the sensor electrode and having a substantially uniform thickness, wherein the inner layer includes a relatively thick, porous backing film and a relatively thin, porous overlaying film that overlays the backing film, and an immobilized glucose oxidase layer interposed between the outer and inner layers and having a substantially uniform thickness, wherein the outer layer is configured to allow glucose and oxygen to diffuse through it to reach the glucose oxidase layer, where the glucose and oxygen react to form reaction products that include hydrogen peroxide, and wherein the inner layer is configured to have a permeability sufficient to pass hydrogen peroxide from the glucose oxidase layer to the face of the sensor electrode. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. An electrode assembly for use in assaying glucose in a solution, the electrode assembly comprising:
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a sensor electrode; and a membrane assembly overlaying the sensor electrode, the membrane assembly including an outer, diffusion-barrier layer positioned to contact the solution, the outer layer having a uniform thickness and a distribution of pores of a specific density and a specific size, an inner, interference-barrier layer contacting a face of the sensor electrode and including a relatively thick, porous backing film and a relatively thin, porous overlaying film that overlays the backing film, the two films together having a uniform thickness, and an immobilized glucose oxidase layer interposed between the outer and inner layers, wherein the outer layer is configured to allow glucose and oxygen to diffuse through it to reach the glucose oxidase layer, where the glucose and oxygen react to form reaction products that include hydrogen peroxide, and wherein the inner layer is configured to have a permeability sufficient to pass hydrogen peroxide from the glucose oxidase layer to the face of the sensor electrode. - View Dependent Claims (13, 14, 15, 16, 17)
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Specification