Biosensor

• US 5,512,159 A
• Filed: 08/19/1994
• Issued: 04/30/1996
• Est. Priority Date: 01/21/1992
• Status: Expired due to Term

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Tsutsumi, Haruhiro, Tokuno, Yoshinobu, Miyazaki, Shoji, Yoshioka, Toshihiko, Nankai, Shiro, Baba, Hideyuki, Kawaguri, Mariko
• Primary Examiner(s): TUNG, TA HSUNG
• Application Number:
  US08/293,131
• Time in Patent Office: 620 Days
• Field of Search: 204/403, 204/412
• US Class Current: 204/403.08
• CPC Class Codes: C12Q 1/001 Enzyme electrodes

Abstract

A biosensor of the present invention is provided with an insulating base plate, an electrode system mainly consisting of a working electrode and a counter electrode formed on the insulating base plate, and a reaction layer on the electrode system. The counter electrode is partially a circular arc. A manufacturing method of the biosensor of the present invention is comprised of a step to form a base by arranging leads, an electrode system, and an insulating layer on an insulating base plate, and a step to form a reaction layer mainly composed of an enzyme on the electrode system. Since the counter electrode is partially in the shape of a circular arc, the reaction layer is easily formed and prevented from delaminating, whereby the measuring accuracy, preservative properties and reliability of the biosensor are improved. The present invention enables highly efficient biosensors to be mass produced at low cost.

Claims

1. A biosensor for measuring a substrate in a liquid sample, comprising:

an insulating base plate having a principle surface,

an electrode system including a working electrode and a counter electrode formed spaced apart on said principle surface of said base plate, and first and second leads respectively connected to said working electrode and said counter electrode, and

a reaction layer formed on said electrode system so as to contact said working electrode and said counter electrode and including an enzyme, a hydrophilic polymer and an electron acceptor,

wherein the electron acceptor is reduced by means of a reaction between the enzyme and the substrate in the liquid sample and is subsequently electrochemically oxidized and a resulting value of oxidation current between the working electrode and the counter electrode is indicative of a concentration of the substrate, and

wherein said counter electrode has a substantially circular outer peripheral edge, a substantially square inner peripheral edge defining a square opening therein having four corners, and opposing generally radial edges defining a gap therebetween extending from a side of said square opening to said outer peripheral edge,

wherein said working electrode has a substantially square outer periphery and is centrally located and aligned within said square opening of counter electrode, and

wherein said first lead extends through said gap of said counter electrode to contact said working electrode.

2. A biosensor for measuring a substrate in a liquid sample, comprising:

an insulating base plate having a principle surface,

an electrode system including a working electrode and a counter electrode formed spaced apart on said principle surface of said base plate, and first and second leads respectively connected to said working electrode and said counter electrode, and

a reaction layer formed on said electrode system so as to contact said working electrode and said counter electrode and including an enzyme, a hydrophilic polymer and an electron acceptor,

wherein the electron acceptor is reduced by means of a reaction between the enzyme and the substrate in the liquid sample and is subsequently electrochemically oxidized and a resulting value of oxidation current between the working electrode and the counter electrode is indicative of a concentration of the substrate, and

wherein said counter electrode has a substantially circular outer peripheral edge, and an inner peripheral edge defining a rectangular opening therein having two inner corners and opposing generally radial edges extending from said two inner corners to said outer peripheral edge,

wherein said working electrode has a substantially rectangular outer periphery and is centrally located and aligned within said rectangular opening of said counter electrode, and

wherein an outer edge of said working electrode has an arc configuration aligned with the outer peripheral edge of said counter electrode, and wherein said first lead contacts said working electrode at said outer edge.

3. A biosensor for measuring a substrate in a liquid sample, comprising:

an insulating base plate having a principle surface,

an electrode system including a working electrode and a counter electrode formed spaced apart on said principle surface of said base plate, and first and second leads respectively connected to said working electrode and said counter electrode, and

a reaction layer formed on said electrode system so as to contact said working electrode and said counter electrode and including an enzyme, a hydrophilic polymer and an electron acceptor,

wherein the electron acceptor is reduced by means of a reaction between the enzyme and the substrate in the liquid sample and is subsequently electrochemically oxidized and a resulting value of oxidation current between the working electrode and the counter electrode is indicative of a concentration of the substrate, and

wherein said counter electrode has a substantially circular outer peripheral edge, and an inner peripheral edge defining an elongate opening therein which is devoid of inner corners and includes opposing generally radial edges defining a gap therebetween extending from a side of said elongate opening to said outer peripheral edge,

wherein said working electrode has a substantially elongate outer periphery devoid of inner corners and is centrally located and aligned within said elongate opening of said counter electrode, and

wherein an outer edge of said working electrode has an arc configuration aligned with the outer peripheral edge of said counter electrode, and wherein said first lead contacts said working electrode at said outer edge.

4. A biosensor as claimed in claim 3, wherein said base plate is elongate and wherein said elongate opening of said counter electrode and said working electrode extending longitudinally along said base plate.

5. A biosensor as claimed in claim 3, wherein said base plate is elongate and wherein said elongate opening of said counter electrode and said working electrode extending laterally along said base plate.

6. A biosensor for measuring a substrate in a liquid sample, comprising:

an insulating base plate having a principle surface,

an electrode system including a working electrode, a counter electrode and a reference electrode formed spaced apart on said principle surface of said base plate, and first, second and third leads respectively connected to said working electrode, said counter electrode and said reference electrode at an outer edge of each electrode, and

a reaction layer formed on said electrode system so as to contact said working electrode and said counter electrode and including an enzyme, a hydrophilic polymer and an electron acceptor,

wherein the electron acceptor is reduced by means of a reaction between the enzyme and the substrate in the liquid sample and is subsequently electrochemically oxidized and a resulting value of oxidation current between the working electrode and the counter electrode is indicative of a concentration of the substrate, and

wherein said working electrode is located between said reference electrode and said counter electrode with parallel extending gaps therebetween, and wherein said outer edges of said working electrode and said counter electrode and said reference electrode extend along a same circular configuration.