Method for detecting or assaying target substance by utilizing oxygen electrode
First Claim
1. A method for detecting or assaying target substance A capable of specifically binding to specific substance B, comprising:
- (1) feeding a sample solution expected to contain a target substance A to a porous support to allow the target substance A to react with a specific substance B labeled with a redox catalyst;
(2) allowing the sample solution from step (1) to migrate to a member composing a part of the porous support where a third substance A′
capable of specifically binding to specific substance B is immobilized, thereby immobilizing the specific substance B in a free state;
(3) allowing the sample solution from step (2) to migrate to a sensing surface of an oxygen electrode in contact with a part of the porous support to bring the solution and a substrate of the redox catalyst into contact with the sensing surface of the oxygen electrode, and detecting or measuring an activity of the redox catalyst contained in the solution as a change of an electric current of the oxygen electrode due to consumption of the oxygen in the solution, wherein the area of the sensing surface of the oxygen electrode is 1 mm2 or less, and the thickness of the member on the oxygen electrode is 0.1 to 5 mm; and
(4) detecting the presence or concentration of said target substance A based on the change of the electric current.
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Accused Products
Abstract
A method for detecting or assaying one constituting member in a specific binding pair, for example, the antigen in an antigen/antibody pair, by utilizing specific binding such as binding between an antigen and an antibody, together with redox reaction for detecting a label, wherein an oxygen micro-electrode with a sensing surface area of 1 mm2 or less is used; and an apparatus to which the method is applicable. According to the method and by using the apparatus, redox reaction for assaying the label can be completed in such a short time as several minutes. Therefore, an inexpensive disposable apparatus for household use can be realized.
22 Citations
25 Claims
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1. A method for detecting or assaying target substance A capable of specifically binding to specific substance B, comprising:
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(1) feeding a sample solution expected to contain a target substance A to a porous support to allow the target substance A to react with a specific substance B labeled with a redox catalyst;
(2) allowing the sample solution from step (1) to migrate to a member composing a part of the porous support where a third substance A′
capable of specifically binding to specific substance B is immobilized, thereby immobilizing the specific substance B in a free state;
(3) allowing the sample solution from step (2) to migrate to a sensing surface of an oxygen electrode in contact with a part of the porous support to bring the solution and a substrate of the redox catalyst into contact with the sensing surface of the oxygen electrode, and detecting or measuring an activity of the redox catalyst contained in the solution as a change of an electric current of the oxygen electrode due to consumption of the oxygen in the solution, wherein the area of the sensing surface of the oxygen electrode is 1 mm2 or less, and the thickness of the member on the oxygen electrode is 0.1 to 5 mm; and
(4) detecting the presence or concentration of said target substance A based on the change of the electric current. - View Dependent Claims (17, 21, 22, 23, 24, 25)
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2. A method for detecting or assaying target substance A capable of specifically binding to a specific substance B, comprising:
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(1) feeding a sample solution expected to contain a target substance A to a porous support to allow the target substance A to react with a specific substance B labeled with a redox catalyst;
(2) allowing the sample solution from step (1) to migrate to a member composing a part of the porous support where a third substance B′
capable of specifically binding to specific substance A is immobilized, thereby immobilizing the specific substance B bound to the target substance A;
(3) bringing the part of the porous support to which the specific substance B is immobilized in step (2) and a substrate of the redox catalyst into contact with the sensing surface of the oxygen electrode, and detecting or measuring an activity of the redox catalyst as a change of an electric current of the oxygen electrode due to consumption of the oxygen in the solution, wherein the area of the sensing surface of the oxygen electrode is 1 mm2 or less, and the thickness of the member on the oxygen electrode is 0.1 to 5 mm; and
(4) detecting the presence or concentration of said target substance A based on the change of the electric current. - View Dependent Claims (5, 8, 11, 14, 18)
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3. A method for detecting or assaying target substance A capable of specifically binding to specific substance B, comprising:
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(1) adding a known amount of third substance A′
to a sample solution expected to contain a target substance A, said third substance A′
being capable of specifically binding to specific substance B and labeled with a redox catalyst;
(2) feeding the sample solution from step (1) to a member composing a part of a porous support where a specific substance B is immobilized, thereby allowing the target substance A and the third substance A′
to competitively react with and immobilize to the specific substance B;
(3) bringing the part of the porous support to which the third substance A′
is immobilized in step (2) and a substrate of the redox catalyst into contact with the sensing surface of the oxygen electrode, and detecting or measuring an activity of the redox catalyst as a change of an electric current of the oxygen electrode due to consumption of the oxygen in the solution, wherein the area of the sensing surface of the oxygen electrode is 1 mm2 or less, and the thickness of the member on the oxygen electrode is 0.1 to 5 mm, and(4) detecting the presence or the concentration of the target substance A based on the change of the electric current. - View Dependent Claims (6, 9, 12, 15, 19)
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4. A method for detecting or assaying target substance A capable of specifically binding to specific substance B, comprising:
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(1) allowing a third substance A′
capable of specifically binding to specific substance B and labeled with a redox catalyst to react with a specific substance B immobilized to a member composing a part of a porous support to immobilize a known amount of the third substance A′
;
(2) feeding a sample solution expected to contain a target substance A to said member composing a part of the porous support, and allowing the target substance A and the immobilized third substance A′
to compete with each other and to partially free the third substance A′
in an amount depending on the amount of the target substance A;
(3) bringing the part of the porous support containing the still immobilized third substance A′
after step (2) and a substrate of the redox catalyst into contact with a sensing surface of an oxygen electrode, and detecting or measuring an activity of the redox catalyst as a change of an electric current of the oxygen electrode due to consumption of the oxygen in the solution, or(3′
) allowing the sample solution from step (2) containing the freed third substance A′
to migrate to a sensing surface of an oxygen electrode in contact with a part of the porous support to bring the solution and a substrate of the redox catalyst into contact with the sensing surface of the oxygen electrode, and detecting or measuring an activity of the redox catalyst contained in the solution as a change of an electric current of the oxygen electrode due to consumption of the oxygen in the solution, wherein the area of the sensing surface of the oxygen electrode is 1 mm2 or less, and the thickness of the member on the oxygen electrode is 0.1 to 5 mm; and
(4) detecting the presence or the concentration of the target substance A based on the change of the electric current. - View Dependent Claims (7, 10, 13, 16, 20)
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Specification