Sensor and method for analyte determination

• US 4,919,767 A
• Filed: 08/04/1988
• Issued: 04/24/1990
• Est. Priority Date: 08/04/1987
• Status: Expired due to Fees

• Current Assignee: The Victoria University of Manchester
• Original Assignee: Imperial Chemical Industries PLC (IMPERIAL CHEMICAL INDUSTRIES)
• Inventors: Vadgama, Pankaj M., Tang, Lian X.
• Primary Examiner(s): NOT, DEFINED
• Application Number:
  US07/228,153
• Time in Patent Office: 628 Days
• Field of Search: 435/817, 435/291, 435/4, 435/288, 204/1 E, 204/403
• US Class Current: 205/778
• CPC Class Codes: C12Q 1/001 Enzyme electrodes
• CPC Class Codes: C12Q 1/002 Electrode membranes
• CPC Class Codes: Y10S 435/817 Enzyme or microbe electrode

Abstract

A sensor of the enzyme-electrode type comprising an electrode and a membrane permeable to liquids and solutes which is positioned between the electrode and a specimen containing the analyte to be determined, is characterized by the fact that a layer of a porous material, positioned in the membrane between the enzyme-containing layer and the specimen, has been treated to at least partially fill the pores with a liquid of limited volatility which is not significantly soluble in water and is to some degree a solvent for the analyte.

Claims

1. A sensor of the enzyme-electrode type for the determination of an analyte in a sample, which analyte is convertible in the presence of an enzyme into a species which is detectable by the sensor, which sensor comprises an electrode and a membrane permeable to liquids and solutes which is positioned between the electrode and a specimen containing the analyte, which membrane comprises a first layer containing at least one enzyme and a second layer positioned between the enzyme-containing layer and the specimen, wherein said second layer contains an area through which analyte can pass, in the form of a liquid membrane formed from a porous material of which the pores have been at least partially filled with a liquid having the ability to pass the analyte while rejecting other species in the sample.

2. A sensor according to claim 1, wherein said membrane further comprises a third layer of material disposed between the enzyme-containing layer and the electrode.

3. A sensor according to claim 2, wherein said third layer is formed from a material selected from the group consisting of polymethylmethacrylate, polyurethane and cellulose acetate.

4. A sensor according to claim 1, wherein the porous material is selected from the group consisting of polycarbonates, polyurethanes and modified celluloses.

5. A sensor according to claim 1, wherein the porous material has a porosity within the range from 0.05 to 20 percent.

6. A sensor of the enzyme-electrode type for the determination of an analyte in a specimen containing said analyte, said analyte being convertible in the presence of an enzyme into a species detectable by the sensor, which sensor comprises an electrode and a membrane permeable to liquids and solutes which is positioned between the electrode and the specimen, said membrane comprising an enzyme-containing layer, a layer of material disposed between said enzyme-containing layer and said electrode and a layer disposed between said enzyme-containing layer and said specimen and having an area of a porous material of average pore diameter less than 5 μ

m, said pores being at least partially filled with a non-aqueous liquid having the ability to pass the analyte while rejecting other species in the specimen.

7. A sensor according to claim 6, wherein the liquid comprises a lipid.

8. A sensor according to claim 7, wherein said lipid is selected from the group consisting of isopropyl myristate and lecithin.

9. A sensor according to claim 6, wherein the liquid comprises an ester of a fatty acid.

10. A sensor according to claim 9, wherein the fatty acid ester is selected from the group consisting of methyl oleate and methyl linoleate.

11. A sensor according to claim 6, wherein the membrane contains a layer formed from a polymeric material selected from the group consisting of polyarylsulphones and polyarylketones.

12. An enzyme-electrode sensor for determining an analyte in a specimen, which analyte is convertible in the presence of an enzyme into a species detectable by the sensor, which sensor comprises an electrode, a first layer of a material selected from polymethylmethacrylate, polyurethane and cellulose acetate, disposed between the electrode and the specimen, an enzyme-containing second layer overlying said first layer, and a porous third layer overlying said second layer, which porous layer comprises a material selected from polycarbonates, polyurethanes and modified celluloses, has an average pore diameter less than 5 μ

m and has said pores at least partially filled with a liquid comprising a lipid or a fatty acid ester.

13. A method for determining an analyte in a specimen which comprises contacting the specimen with the outer layer of a membrane, permeable to liquids and solutes and comprising one or more enzymes, in the presence of which the analyte is convertible into a species detectable by a sensor which incorporates the membrane, and one or more layers of material, and measuring the response of the sensor to the species, characterized in that a layer in the membrane between the enzyme and the specimen contains an area through which analyte can pass formed from a porous material which has been treated to fill its pores wholly or partially with a liquid which has the ability to pass the analyte while rejecting other species in the specimen.