Glucose sensitive FET sensor and method of making same

• US 5,543,024 A
• Filed: 09/25/1990
• Issued: 08/06/1996
• Est. Priority Date: 03/03/1987
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Shiono, Satoru, Nakako, Mamiko, Inatomi, Kenichi, Hanazato, Yoshio
• Primary Examiner(s): TUNG, TA HSUNG
• Application Number:
  US07/587,660
• Time in Patent Office: 2,142 Days
• Field of Search: 204/153.12, 204/403, 204/418, 435/14, 435/817, 436/806, 436/531, 427/58, 427/385.5, 427/430.1, 427/443.2
• US Class Current: 257/253
• CPC Class Codes: C12Q 1/006 for glucose
• CPC Class Codes: G01N 27/4145 specially adapted for biomolecules, e.g. gate electrode with immobilised receptors
• CPC Class Codes: Y10S 435/817 Enzyme or microbe electrode
• CPC Class Codes: Y10S 436/806 Electrical property or magnetic property

Abstract

A glucose sensitive FET sensor is provided which includes a substrate, a source electrode formed in the substrate, a drain electrode formed in the substrate, a hydrogen ion sensitive film formed on the substrate to cover the source electrode and the drain electrode, and a thin enzyme immobilized membrane formed on the hydrogen ion sensitive film and containing glucose oxidase and gluconolactonase. Also provided is a method of producing a glucose sensitive FET sensor which includes the steps of preparing an enzyme immobilized membrane as a thin film containing glucose oxidase and gluconolactonase and forming the membrane on a hydrogen ion sensitive film which is formed on a substrate to cover a source electrode and a drain electrode, both of which are formed in the substrate.

Claims

1. A glucose sensitive FET sensor, comprising:

a substrate;

a source electrode formed in said substrate;

a drain electrode formed in said substrate;

a hydrogen ion sensitive film formed on said substrate to cover said source electrode and said drain electrode; and

a thin enzyme immobilized membrane formed on said hydrogen ion sensitive film and containing glucose oxidase and gluconolactonase.

2. A glucose sensitive FET sensor as claimed in claim 1, wherein the activity ratio of said glucose oxidase to said gluconolactonase is in the range of from 1:

0.5 to 1;

10.

3. A glucose sensitive FET sensor as claimed in claim 1, wherein the activity ratio of said glucose oxidase to said gluconolactonase is in the range of from 1:

2 to 1;

3.

4. A glucose sensitive FET sensor as claimed in claim 1 wherein the thickness of said thin enzyme immobilized membrane is about 1 μ

m.

5. A glucose sensitive FET sensor as claimed in claim 1 wherein said film enzyme immobilized membrane is formed from 2,5-bis (4'"'"'-azide-2'"'"'-sulfobenzal) cyclopentanone sodium salt and a water soluble resin of polyvinyl pyrrolidone in addition to said glucose oxidase and gluconolactonase.

6. A glucose sensitive FET sensor as claimed in claim 5 wherein said polyvinyl pyrrolidone has a molecular weight of 360,000.

7. A method of producing a glucose sensitive FET sensor, comprising the steps of:

preparing an enzyme immobilized membrane as a thin film containing glucose oxidase and gluconolactonase; and

forming said membrane on a hydrogen ion sensitive film which is formed on a substrate to cover a source electrode and a drain electrode both of which are formed in said substrate.

8. A method of producing a glucose sensitive FET sensor as claimed in claim 7, wherein said preparation step of said membrane further comprises the steps of:

preparing an aqueous solution of a water soluble photosensitive resin which contains glucose oxidase and gluconolactonase;

coating said aqueous solution of said water soluble photosensitive resin on said hydrogen ion sensitive film formed on said substrate to cover said source electrode and said drain electrode thereon; and

irradiating a predetermined portion of said aqueous solution coated on said substrate with light, thereby forming an enzyme immobilized membrane as a thin film.

9. A method of producing a glucose sensitive FET sensor as claimed in claim 7, wherein the activity ratio of said glucose oxidase to said gluconolactonase is in the range of from 1:

0.5 to 1;

10.

10. A method of producing a glucose sensitive FET sensor as claimed in claim 7, wherein the activity ratio of said glucose oxidase to said gluconolactonase is in the range of from 1:

2 to 1;

3.

11. A method of producing a glucose sensitive FET sensor as claimed in claim 7, wherein the thickness of said enzyme immobilized membrane is in the micron order.