Biosensor, and a method and a device for quantifying a substrate in a sample liquid using the same
First Claim
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1. A method for quantifying a substrate in a sample liquid by using a biosensor comprising:
- an electrically insulating substrate;
an electrode system formed on the substrate including a working electrode, a counter electrode and a third electrode used for detecting a liquid junction; and
a reaction layer that is formed over at least the working electrode and the counter electrode of the electrode system and includes an oxidoreductase;
wherein the method of quantifying the substrate comprises the steps of;
applying a voltage between the counter electrode and the third electrode;
supplying a sample liquid to the reaction layer;
detecting an electrical change between the counter electrode and the third electrode caused by supplying the sample liquid to the reaction layer;
applying a voltage between the working electrode and both of the third electrode and the counter electrode after detecting the electrical change; and
measuring a current flowing between the counter electrode and the working electrode after applying the voltage.
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Abstract
The biosensor of this invention can quantify a substrate in a sample liquid by electrochemically measuring the amount of an electron acceptor that has been reduced by electrons generated in a reaction between the substrate and an oxidoreductase. The biosensor has an electrically insulating substrate and an electrode system formed on the substrate including a working electrode, a counter electrode and a third electrode used for detecting a liquid junction. The third electrode can be used merely for detecting a liquid junction, or can be used as both a reference electrode and a liquid junction detecting electrode.
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Citations
13 Claims
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1. A method for quantifying a substrate in a sample liquid by using a biosensor comprising:
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an electrically insulating substrate; an electrode system formed on the substrate including a working electrode, a counter electrode and a third electrode used for detecting a liquid junction; and a reaction layer that is formed over at least the working electrode and the counter electrode of the electrode system and includes an oxidoreductase; wherein the method of quantifying the substrate comprises the steps of; applying a voltage between the counter electrode and the third electrode; supplying a sample liquid to the reaction layer; detecting an electrical change between the counter electrode and the third electrode caused by supplying the sample liquid to the reaction layer; applying a voltage between the working electrode and both of the third electrode and the counter electrode after detecting the electrical change; and measuring a current flowing between the counter electrode and the working electrode after applying the voltage. - View Dependent Claims (2)
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3. A method for quantifying a substrate in a sample liquid by using a biosensor comprising:
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an electrically insulating substrate; an electrode system formed on the substrate including a working electrode, a counter electrode and a third electrode used for detecting a liquid junction; and a reaction layer that is formed over at least the working electrode and the counter electrode of the electrode system and includes an oxidoreductase; wherein the method of quantifying the substrate comprises the steps of; applying a voltage between the counter electrode and the third electrode; supplying a sample liquid to the reaction layer; detecting an electrical change between the counter electrode and the third electrode caused by supplying the sample liquid to the reaction layer; applying a voltage between the working electrode and the counter electrode after detecting the electrical change; and measuring a current flowing between the counter electrode and the working electrode after applying the voltage. - View Dependent Claims (4)
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5. A quantifying device for a substrate contained in a sample liquid comprising:
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a biosensor comprising;
an electrically insulating substrate;an electrode system formed on the substrate including a working electrode, a counter electrode and a third electrode used for detecting a liquid junction; and a reaction layer that is formed over at least the working electrode and the counter electrode of the electrode system and includes an oxidoreductase; wherein the quantifying device additionally comprises; means for detecting an electrical change between the counter electrode and the third electrode caused by supplying a sample liquid to the reaction layer; means for applying a voltage between the working electrode and both of the third electrode and the counter electrode after detecting the electrical change; and means for measuring a current flowing between the working electrode and the counter electrode. - View Dependent Claims (6)
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7. A quantifying device for a substrate contained in a sample liquid comprising:
a biosensor comprising; an electrically insulating substrate; an electrode system formed on the substrate including a working electrode, a counter electrode and a third electrode used for detecting a liquid junction; and a reaction layer that is formed over at least the working electrode and the counter electrode of the electrode system and includes an oxidoreductase; wherein the quantifying device additionally comprises; means for detecting an electrical change between the counter electrode and the third electrode caused by supplying a sample liquid to the reaction layer; means for applying a voltage between the working electrode and the counter electrode after detecting the electrical change; and means for measuring a current flowing between the working electrode and the counter electrode. - View Dependent Claims (8)
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9. A quantifying device for a substrate contained in a sample liquid, comprising a biosensor comprising:
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an electrically insulating substrate; an electrode system formed on the substrate including a working electrode, a counter electrode and a third electrode used for detecting a liquid junction; and a reaction layer that is formed over at least the working electrode and the counter electrode of the electrode system and includes an oxidoreductase; wherein the quantifying device additionally comprises a measuring device to which the biosensor is removably connected, wherein the measuring device includes; current/voltage converting circuits connected to the third electrode of the biosensor;
A/D converting circuits connected to the current/voltage converting circuits;
current/voltage converting circuits which connects the working electrode of the biosensor via a switch;
A/D converting circuits connected to the current/voltage converting circuits; and
a controller connected to the respective A/D converting circuits, the switch being turned ON or OFF with respect to the working electrode by a control of the controller, andwherein an electrical change between the counter electrode and the third electrode, caused by a supply of a sample liquid to the reactive layer, is detected by the control portion under a condition that the switch is insulated from the working electrode, and then a voltage is applied between the working electrode and both of the third electrode and the counter electrode under a condition that the switch is connected to the working electrode and a current flowing between the working electrode and the counter electrode is measured. - View Dependent Claims (10)
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11. A quantifying device for a substrate contained in a sample liquid, comprising a biosensor comprising:
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an electrically insulating substrate; an electrode system formed on the substrate including a working electrode, a counter electrode and a third electrode used for detecting a liquid junction; and a reaction layer that is formed over at least the working electrode and the counter electrode of the electrode system and includes an oxidoreductase; wherein the quantifying device additionally comprises a measuring device to which the biosensor is removably connected, wherein the measuring device includes; current/voltage converting circuits connected to the third electrode of the biosensor;
A/D converting circuits connected to the current/voltage converting circuits;
current/voltage converting circuits which connects the working electrode of the biosensor via a switch;
A/D converting circuits connected to the current/voltage converting circuits; and
a controller connected to the respective A/D converting circuits, the switch being turned ON or OFF with respect to the working electrode by a control of the controller, andwherein an electrical change between the counter electrode and the third electrode, caused by a supply of a sample liquid to the reactive layer, is detected by the control portion under a condition that the switch is insulated from the working electrode, and then a voltage is applied between the working electrode and the counter electrode under a condition that the switch is connected to the working electrode and a current flowing between the working electrode and the counter electrode is measured. - View Dependent Claims (12)
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13. A quantifying device for a substrate contained in a sample liquid, comprising a biosensor comprising:
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an electrically insulating substrate; an electrode system formed on the substrate including a working electrode, a counter electrode and a third electrode used for detecting a liquid junction; and a reaction layer that is formed over at least the working electrode and the counter electrode of the electrode system and includes an oxidoreductase; wherein the quantifying device additionally comprises a measuring device to which the biosensor is removably connected, wherein the measuring device includes; current/voltage converting circuits switchably connected to the third electrode of the biosensor and the working electrode;
A/D converting circuits connected to the current/voltage converting circuits;
a controller connected to the respective A/D converting circuits, the switch being alternatively connected to the working electrode and the third electrode by a control of the controller, andwherein an electrical change between the counter electrode and the third electrode, caused by a supply of a sample liquid to the reactive layer, is detected by the control portion under a condition that the switch is connected to the third electrode, and then a voltage is applied between the working electrode and the counter electrode under a condition that the switch is connected to the working electrode and a current flowing between the working electrode and the counter electrode is measured.
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Specification