WO2008066123A1

WO2008066123A1 - Biosensor utilizing carbon nanotube

Info

Publication number: WO2008066123A1
Application number: PCT/JP2007/073076
Authority: WO
Inventors: Fumiyo Kurusu; Masao Gotoh; Isao Karube; Haruki Tsunoda; Asami Saito; Toshiaki Tsubone; Hiroshi Yamamoto; Takuya Kadowaki
Original assignee: National Institute Of Advanced Industrial Science And Technology; Kyowa Medex Co., Ltd.; Jfe Engineering Corporation
Priority date: 2006-11-30
Filing date: 2007-11-29
Publication date: 2008-06-05
Also published as: JP4863398B2; JP2008157930A

Abstract

Disclosed is a biosensor having a detection electrode, wherein the material for the detection electrode is a boron-containing carbon nanotube (CNT). In the biosensor, the detection electrode is formed, for example, by mixing the boron-containing CNT with a mineral oil, an ionic liquid or a polymeric binder resin to produce a paste-like material and filling the paste-like material into a cylindrical container. The biosensor can detect a substance contained in a sample without being affected by any electrochemically active substance including a reductive interfering substance, can improve the detection sensitivity for the substance, and has a simplified construction.

Description

Specification

Biosensor using carbon nanotubes

Technical field

[0001] The present invention relates to a biosensor using carbon nanotubes. More specifically, the present invention relates to a biosensor using carbon nanotubes that are suitably used as a biosensor excellent in selectivity for a measurement interfering substance having high catalyst activity.

Background art

[0002] When a liquid biological sample such as blood or urine is measured using a biosensor based on an electrochemical detection means, reducing interfering substances such as ascorbic acid, uric acid, and acetoaminophen coexist in the sample. Electrochemical or chemical interference is always a problem. Measures to avoid such problems include (1) interference substance permeation limiting membrane method, (2) electrolytic oxidation method, and (3) differential measurement method. In designing biosensors, reducing interference substances It is extremely important to take measures to eliminate the effects of

[0003] On the other hand, as a new countermeasure method in recent years, attention has been paid to the use of single-bonn nanotubes (CNTs) as a sensing electrode when constructing a biosensor. CNT is a new nanomaterial discovered in 1991. It is a hexagonal net-shaped dalafen sheet in which carbon atoms are regularly arranged in a hexagonal shape, rounded into a cylindrical shape. A single-layer CNT is a single-walled CNT, and a multi-walled CNT-type is a multi-walled CNT.

[0004] When an electric field is applied to CNTs, electric field concentration occurs at the end of the tube, and electrons can be easily extracted to the outside. When the extracted electrons are applied to the fluorescent screen, it emits light, so it can be used as a light source or display. Compared with conventional electron emission sources, CNTs have a smaller cross-sectional size, so electric field concentration is effectively generated. As a result, the voltage required for electron emission is small, and a high vacuum environment is unnecessary, so that it can be widely used as an electron emission source for electron emission devices. Furthermore, it has excellent mechanical strength, thermal conductivity, flexibility, thermal stability, chemical stability, etc., and can be used widely as a composite composite material. [0005] CNTs are expected to be applied to a wide range of fields from electronics to energy, and the application of CNTs to detection electrodes of biosensors is one of them.

[0006] To date, there have been many reports that it is possible to detect a test substance at a low potential that is not affected by reducing interference substances by using CNT as a detection electrode of a biosensor. However, the CNTs used are single-walled CNT and multi-walled CNT, CNTs with functional groups, hollow_type CNTs, bamboo-type CNTs, CNTs doped with nitrogen Etc. Even when these CNTs are used as detection electrodes for biosensors, for example, the potential for the oxidation reaction of ascorbic acid, uric acid, and acetaminophen is lower! However, it is difficult to increase the CNT content in electrode formation, and thus has a problem in further improving the conductivity.

Patent Document 1: JP 2006-317360

Disclosure of the invention

Problems to be solved by the invention

[0007] An object of the present invention is to detect a test substance contained in a sample without being affected by an electrochemically active substance such as a reducing interfering substance and to improve the detection sensitivity of the test substance. It is an object of the present invention to provide a biosensor that is improved and whose structure is simplified.

Means for solving the problem

[0008] The object of the present invention is achieved by a biosensor having a detection electrode, wherein the detection electrode material is a carbon nanotube containing boron.

That is, the present invention specifically includes the following configurations (1) to (; 13).

(1)

A biosensor having a detection electrode, wherein the detection electrode material is a carbon nanotube containing boron.

(2)

The biosensor according to (1), wherein the carbon nanotube is a multi-walled carbon nanotube having a diameter of less than lOOnm. The biosensor according to (1) or (2), wherein carbon nanotubes containing boron are mixed with mineral oil, ionic liquid, or polymer binder resin and used in a paste form.

(Four)

The biosensor according to (1) or (2), wherein carbon nanotubes containing boron are dispersed in water or an organic solvent.

(Five)

The biosensor according to (3), wherein the detection electrode is a cylindrical electrode in which a carbon nanotube prepared in a paste form is filled in a cylindrical container.

(6)

The biosensor according to (3) or (4), wherein the detection electrode is a carbon nanotube containing boron on an insulating substrate.

(7)

The biosensor according to (3) or (4), wherein the detection electrode is a carbon electrode, platinum electrode, gold electrode, or silver electrode on which carbon nanotubes containing boron are arranged. (8)

The biosensor as set forth in (6), which is a carbon nanotube disposed on an insulating substrate by a carbon nanotube force screen printing method containing boron.

(9)

The biosensor according to any one of (1) to (8), wherein the detection electrode is an electrode having an enzyme immobilized on the electrode!

(Ten)

The biosensor according to (9), wherein the detection electrode is an electrode in which a single mediator molecule is held on the electrode.

(11)

The biosensor according to (0), wherein a mediator single molecular force S mediator molecular layer is formed (; L0). (12) By setting the inter-electrode voltage to a specific voltage, the effect of measurement interfering substances can be avoided, and the target substance can be selectively measured. (1) to (; 11)! / Sensor. (13)

(1) to (; 12)! A method for detecting or quantifying a test substance in a sample using the biosensor according to any one of the methods, wherein the electrode voltage is applied after contacting the sample with the detection electrode. Is set to a specific voltage and applied.

The invention's effect

[0010] According to the present invention, a biosensor having a simplified configuration is provided. With such a biosensor, a specific substance contained in a sample is affected by an electrochemically active substance such as a reducing interfering substance. It is possible to measure and detect accurately without receiving it. In addition, since the CNT content can be increased when forming the electrode, it has an excellent effect that the conductivity can be further improved as compared with the conventional biosensor using CNT. Such a biosensor can be effectively used as a biosensor for medical diagnosis or health diagnosis, particularly a biosensor for measuring a blood glucose level and a glycated protein that are indicators of diabetes.

Brief Description of Drawings

[0011] FIG. 1 is a graph showing the response to a hydrogen peroxide sample using a detection electrode using boron-containing CNT, graphite powder, or glassy carbon.

[Fig. 2] This is a graph of the response to a hydrogen peroxide sample using a sensing electrode that uses boron-containing CNTs and boron-free CNTs.

[Fig. 3] Another graph showing the response to a hydrogen peroxide sample using a detection electrode using boron-containing CNT, graphite powder, or glassy carbon.

[Fig. 4] A graph showing the response to hydrogen peroxide, ascorbic acid, uric acid, and acetaminophen samples when -0.2 V and +0.6 V are applied using a sensing electrode using boron-containing CNTs. is there.

BEST MODE FOR CARRYING OUT THE INVENTION

[0012] As the CNT in the present invention, a CNT containing boron (hereinafter referred to as "boron-containing CNT") is used. Boron-containing CNTs are composed of boron (B) in addition to carbon (C) Including For example, there are those in which boron atoms are incorporated into the skeleton (network) constituting CNT, such as those in which some carbon atoms are replaced by boron atoms, but are not limited to this, for example, in the CNT cavity and / or Alternatively, those having boron adsorbed on the surface are also included, and those having a boron content of 0.01 to 10% by weight, preferably 0.1 to 7% by weight are used.

[0013] The shape of the CNT is not particularly limited, and the force to use either a single layer or a multilayer is preferable. A multilayer CNT having a diameter of less than lOOnm, preferably formed by nesting a plurality of cylindrical darafen. Specifically, graphene having a diameter of less than lOOnm, preferably 5 to 50 nm, a length force of 1 to 100 ^ m, preferably 1 to 1001, and 2 to 100 layers, preferably 5 to 20 graphenes Sheets that overlap are used.

[0014] As such boron-containing CNTs, for example, known ones such as boron-containing CNTs described in Patent Documents 2 to 3 below can be used without particular limitation,

(1) Mix boron compounds such as boron oxide and boric acid with CNT and heat them under inert gas atmosphere at high temperature

(2) In addition to the above boron compounds, carbonaceous raw materials containing boron components such as simple boron, boron carbide, and compounds of boron and various metals are synthesized by an arc discharge method in a hydrogen gas atmosphere.

Any known method can be used without particular limitation.

Patent Document 2: JP 2006-240932 A

Patent Document 3: JP 2006-188384 A

[0015] Because CNTs containing boron and boron have high dispersibility in solvents, etc., when CNTs are mixed in a solution or resin, they have excellent properties when they can be dispersed uniformly.

[0016] Therefore, the state of the boron-containing CNT in the present invention at the time of electrode formation is not particularly limited. However, when powdered CNT is used, mineral oil, ionic liquid, or tetra It is used by appropriately mixing with a high molecular weight binder resin such as fluoroethylene or naphthion, and by dispersing it appropriately in a solvent such as water or organic solvent by acid treatment or ultrasonic treatment. Preferably Yes.

[0017] The method for producing a detection electrode using boron-containing CNTs in the present invention is not particularly limited. Force S, for example, a method of packing the paste in a cylindrical container such as a non-conductive substance such as plastic or a conductive metal, Method of placing paste or dispersion solution in the required size and shape on an insulating substrate such as silicon or polyethylene terephthalate (PET), paste or dispersion solution on the surface of commercially available electrodes such as carbon, platinum, gold, silver There is a method of applying and arranging, and there is !!, a method of forming electrodes of the required size and shape by screen printing on an insulating substrate such as PET using paste or dispersion solution. . When forming a detection electrode on an insulating substrate by screen printing using a dispersion solution, it is preferable to dissolve a resin such as ethyl cellulose in the dispersion solution.

[0018] The amount of the boron-containing CNT contained in the detection electrode is not particularly limited, but the content and the conductivity necessary for use as an electrode are ensured and the effect of the CNT is exhibited. In the case of detecting hydrogen peroxide, for example, in the total amount with the dispersion medium that is preferred, it is preferable to use about 10 to 99% by weight from the viewpoint of maintaining the conductivity of the electrode and ease of processing. . In addition, when hydrogen peroxide is detected using a paste electrode prepared by mixing with mineral oil, about 40 to 95% by weight is desirable. Also, conventional CNTs that do not contain boron (boron-free), such as hollow CNTs or bamboo CNTs, cannot retain their shape as detection electrodes if the content is increased to 10% by weight or more. On the other hand, the boron-containing CNT in the present invention can increase the content in the formation of the detection electrode and improve the conductivity as compared with the conventional boron-free CNT.

[0019] In addition to the detection electrode, a biosensor is constructed by providing a counter electrode and, if necessary, a reference electrode.

[0020] The biosensor of the present invention can be used for detection and quantification of a test substance in a sample. Detection of the test substance in the sample can be performed by bringing the sample into contact with the detection electrode and then applying the electrode with a specific voltage set. By using the biosensor of the present invention, it is possible to avoid the influence of measurement interfering substances and selectively detect a test substance. Can do. For example, when detecting sugar (glucose) in blood or urine, ascorbic acid, uric acid, acetoaminophene, etc., which are not obtained with hydrogen peroxide alone, react with the electrode when applied to the electrode. Electrodes containing CNTs can be set in a state where they react only with hydrogen peroxide by selecting a voltage (referred to here as a specific voltage) and are not easily affected by these contaminants, and have excellent selectivity. A biosensor can be formed. Such a specific voltage varies depending on the test substance, but is generally about -0.5 to +0.4 IV when a silver / silver chloride electrode is used as a reference.

[0021] The determination of the test substance in the sample can also be performed according to the detection method of the test substance. In other words, after the sample is brought into contact with the detection electrode, the voltage between the electrodes is set to a specific voltage and applied, and the obtained information amount (for example, current value) is calculated based on the test substance prepared in advance and the information amount. The force S is used to quantify the test substance in the sample by comparing it with a calibration curve showing the relationship between and.

[0022] Further, for detection or quantification of a test substance! /, An enzyme that can convert the test substance into a substance that can be oxidized or reduced on an electrode, an enzyme substrate, etc. Enzymes and enzyme substrates that can generate substances that can be oxidized or reduced on the electrode from the test substance are used. Here, examples of the substance that can be oxidized or reduced on the electrode include hydrogen peroxide, potassium ferricyanide, potassium ferrocyanide, and the like. Specific examples are shown below.

[0023] When the test substance is glucose, for example, glucose oxidase is allowed to act on glucose in the sample, and the generated hydrogen peroxide is reduced or oxidized on the electrode to detect or quantify glucose. Can do.

[0024] When the test substance is a glycated protein such as glycated hemoglobin or glycated albumin, for example, a glycated peptide and / or glycated amino acid is released by allowing a protease to act on the glycated protein in the sample, and then the glycated peptide generated. By allowing glycated peptide oxidase and / or glycated amino acid oxidase to act on the glycated amino acid and reducing or oxidizing the generated hydrogen peroxide on the electrode, the glycated protein can be detected or quantified.

[0025] When the test substance is lactic acid, for example, lactic acid is allowed to act on lactic acid in the sample, and the generated hydrogen peroxide is reduced or oxidized on the electrode to detect or quantify lactic acid. The power S to do.

[0026] When the test substance is uric acid, for example, uricase is allowed to act on uric acid in the sample, and the generated hydrogen peroxide is reduced or oxidized on the electrode, whereby uric acid can be detected or quantified.

[0027] When the test substance is urea nitrogen, for example, urease is allowed to act on urea in the sample, and the resulting ammonia is further added in the presence of α_ketoglutarate, NADH (reduced coenzyme) and potassium ferricyanide. By reacting glutamate dehydrogenase and oxidizing the produced potassium ferrocyanide on the electrode, urea nitrogen can be detected or quantified.

[0028] When the test substance is creatine, for example, creatininase, creatinase, and sarcosine oxidase are sequentially acted on creatine in the sample, and the generated hydrogen peroxide is reduced or oxidized on the electrode. Creathun can be detected or quantified.

[0029] When the test substance is sulfate-conjugated bile acid, for example, the sulfate-conjugated bile acid in the sample was produced by sequentially reacting bile acid sulfate sulfatase and β-hydroxysteroid dehydrogenase in the presence of NAD ⁺ and potassium ferricyanide. By oxidizing potassium ferrocyanide on the electrode, sulfate-conjugated bile acids can be detected or quantified.

[0030] When the test substance is glutamate oxalate acetate transaminase, for example, the glutamate oxalate acetate transaminase in the sample is allowed to act on α-ketoglutarate and aspartate, and the resulting glutamate is further reacted with glutamate oxidase. By reducing or oxidizing hydrogen oxide on the electrode, glutamate oxalate acetic acid transaminase can be detected or quantified.

[0031] When the test substance is glutamate pyruvate transaminase, for example, it was generated by allowing α-ketoglutarate and alanine to act on glutamate pyruvate transaminase in the sample, and further causing glutamate oxidase to act on the resulting glutamate By reducing or oxidizing hydrogen peroxide on the electrode, glutamate pyruvate transaminase can be detected or quantified.

[0032] When the test substance is cholesterol, for example, cholesterol in the sample is allowed to act on cholesterol, and the generated hydrogen peroxide is reduced or oxidized on the electrode. Thus, cholesterol can be detected or quantified.

[0033] When the test substance is neutral fat, for example, lipoprotein lipase, glycerol kinase and glyce-3-phosphate oxidase are allowed to act on the neutral fat in the sample, and the generated hydrogen peroxide is reduced on the electrode. Alternatively, it can be detected by the ability S to detect or quantify neutral fat by oxidation.

[0034] When the test substance is a fatty acid, for example, a fatty acid in a sample is allowed to act on a fatty acid in a sample in the presence of adenosine-5'-triphosphate (ATP) and coenzyme A (CoA) to further generate a acyl-CoA synthase. Fatty acid can be detected or quantified by reacting the acyl-CoA with acyl-CoA oxidase and reducing or oxidizing the generated hydrogen peroxide on the electrode.

[0035] When the test substance is ammonia, for example, glutamate dehydrogenase is allowed to act on ammonia in the sample in the presence of α_ketoglutarate, NADH and potassium ferricyanide, and the generated potassium ferrocyanide is oxidized on the electrode. With force S to detect or quantify ammonia.

[0036] When the test substance is bilirubin, for example, bilirubin can be obtained by oxidizing potassium ferrocyanide generated by, for example, acting bilirubin oxidase in the presence of potassium ferricyanide on the bilirubin in the sample on the electrode. Can be detected or quantified.

[0037] The enzymes described above are immobilized on the detection electrode and the force mixed in the boron-containing CNT. The method for immobilizing the enzyme on the detection electrode is not particularly limited. For example, the detection electrode is immersed in water or a buffer solution in which the enzyme is dissolved, or the enzyme or the water is dissolved in the electrode. A method of physically or chemically immobilizing enzymes, etc. by dropping them, etc., introducing functional groups such as carboxyl groups and amino groups into CNTs by acid treatment, etc., and then immobilizing them by reacting them. A method, for example, a method of immobilizing an enzyme or the like on a detection electrode using a cross-linking reagent such as dartalaldehyde or bovine serum albumin, or after forming a gel film of a hydrophilic polymer or the like on the detection electrode. Examples thereof include a method of immobilizing an enzyme or the like, or a method of immobilizing an enzyme or the like in the membrane after a conductive polymer membrane such as polythiophene is formed on the detection electrode.

[0038] In the detection or quantification of the test substance, for example, the reaction may be performed using a dissolved enzyme concentration. It is effective to use a single molecule of mediator for the purpose of expanding the detection range when the rate is limited and only a high concentration sample can be measured. When using a single mediator molecule, it is preferable to hold the single mediator molecule on the detection electrode in the immobilized membrane of the physiologically active substance of the enzyme formed on the detection electrode or separately from this. . The kind of mediator molecule is not particularly limited, and for example, at least one kind such as potassium ferricyanide, potassium ferrocyanide, pheucose and derivatives thereof, viologens and methylene blue is used.

[0039] The sample is not particularly limited as long as it contains a test substance indicating a disease or a health condition, and examples thereof include blood, urine, saliva, sweat, and tears. In detection or quantification of a test substance in a sample, the sample itself may be collected or diluted with water or a buffer solution.

[0040] As a measuring method using the sensor of the present invention, a potential step chronoamperometry or coulometry, a cyclic voltammetry method for measuring an oxidation current or a reduction current is used. As the measurement method, a disposable (disposable) method is desirable, but other methods such as FIA (Flow Injection Analysis) and batch methods may be used.

Example

Next, the present invention will be described with reference to examples.

[0042] Example 1

With the hollow carbon anode and the carbon cathode facing each other, the arc welding power source applies a voltage between the carbon electrodes to perform arc discharge, and the discharge part of the carbon cathode (spots the opposite side of the hollow carbon anode hollow hole). CNT was obtained in (Part). Next, 200 mg of the obtained CNT and 5.0 g of boron oxide (B 0) were reacted in a nitrogen atmosphere containing about 2% hydrogen at about 1000 ° C. for several tens of seconds to synthesize boron-containing CNT. This boron-containing CNT was a multi-wall CNT having a diameter of 5 to 35 nm and a length of 1 m or more, and contained about 5% by weight of boron.

[0043] 90 mg of this boron-containing CNT and 10 mg of mineral oil (product of Aldrich) were kneaded in a mortar for 15 minutes and then packed into a carbon paste electrode (product of BAS, diameter 3 mm) to form a detection electrode. A platinum wire (BAS product) was used as the counter electrode, and a silver / silver chloride electrode (BAS product) was used as the reference electrode. Hydrogen peroxide 0 mmol / L, 1 mmol / L, 5 mmol / L, 10 mmo A 50 mmol / L phosphate buffer solution (pH 7.4) dissolved to a concentration of 1 / L, 25 mmol / L, or 50 mmol / L was used as a measurement sample. A calibration curve was created by applying -0.2 V to the working electrode with the reference electrode immersed, and plotting the current value obtained after 90 seconds against the hydrogen peroxide concentration.

[0044] Comparative Example 1

In Example 1, a detection electrode produced using the same amount of graphite powder instead of boron-containing CNTs was used.

[0045] Comparative Example 2

In Example 1, a detection electrode produced using the same amount of glassy carbon instead of boron-containing CNTs was used.

[0046] The results obtained in Example 1 and Comparative Examples 1 and 2 are shown in FIG. In Example 1 (1 · 1), it is shown that a calibration curve with a high correlation coefficient of .992 can be created at a potential lower than the potential at which ascorbic acid, uric acid, and acetaminophen undergo oxidation. It was. On the other hand, the graphite paste electrode (101) of Comparative Example 1 can only obtain a current value of about 1/30 compared to the detection electrode produced using the boron-containing CNT of Example 1, and Compared with the detection electrode produced using the boron-containing CNT of Example 1, the glassy carbon electrode (1 △ 1) of Comparative Example 2 has a force that can obtain only a current value of about 1/50. .

[0047] From the above results, the detection electrode fabricated using the boron-containing CNT of Example 1 can perform more accurate measurement than the case of using a graphite paste electrode or a glassy carbon electrode. It was suggested that the use of boron-containing CNTs as a material for the detection electrode for constructing a biosensor was extremely effective.

[0048] Comparative Example 3

In Example 1, instead of boron-containing CNTs, a detection electrode produced using the same amount of CNT synthesized by arc discharge without using boron oxide (B 0) was used.

[0049] The results obtained in Comparative Example 3 are shown in Fig. 2 together with the measurement results of Example 1. Compared to the detection electrode made using the boron-containing CNT of Example 1, the detection electrode using boron-free CNT of Comparative Example 3 (one bite) can only obtain a current value of about 1/30. It was very good. Thus, the detection electrode fabricated using the boron-containing CNT of Example 1 is It was suggested that more accurate measurement would be possible compared to the case of using paste electrodes made using CNTs without containing silicon. Therefore, it was shown that it is extremely effective to use boron-containing CNT as the material of the detection electrode for constructing the biosensor.

[0050] Example 2

In Example 1, the detection electrode was produced by changing the amount of boron-containing CNTs to 60 mg and the amount of mineral oil to 40 mg.

[0051] Comparative Example 4

In Example 2, a detection electrode produced using the same amount of graphite powder instead of boron-containing CNTs was used.

[0052] Comparative Example 5

In Example 2, a detection electrode produced using the same amount of glassy carbon instead of boron-containing CNTs was used.

[0053] The results obtained in Example 2 and Comparative Examples 4 to 5 are shown in FIG. In Example 2 (— • 1), it was shown that a linear calibration curve with a correlation coefficient of 0.95 could be created at a potential lower than the potential at which ascorbic acid, uric acid, and acetaminophen undergo oxidation reactions. . On the other hand, the graphite paste electrode (101) of Comparative Example 4 or the glassy carbon electrode (1 △ 1) of Comparative Example 5 is compared with the detection electrode prepared using the boron-containing CNT of Example 2. The slope of the calibration curve was about the same. Based on the above, it is suggested that the detection electrode fabricated using the boron-containing CNT of Example 2 can perform more accurate measurement than when using a graphite paste electrode or a glassy carbon electrode. As in Example 1, it was shown that the use of boron-containing CNTs as a material for the detection electrode for constructing the biosensor was extremely effective.

[0054] Example 3

In Example 1, -0.2 V was applied to the detection electrode with the detection electrode, counter electrode, and reference electrode immersed in 50 mmol / L phosphate buffer (pH 7.4), and after 300 seconds, 5 mmol / L Hydrogen peroxide was added to a concentration of L. Furthermore, ascorbic acid was added after 480 seconds, uric acid was added after 660 seconds, and acetaminophen was added at a concentration of 0.5 mmol / L after 840 seconds. In addition, the current value change at that time was measured.

[0055] Comparative Example 6

In Example 3, the change in current when +0.6 V was applied to the detection electrode was measured.

[0056] The results obtained in Example 3 and Comparative Example 6 are shown in FIG. In Example 3 (solid line), by applying a potential lower than the potential at which oxidation of ascorbic acid, uric acid, and acetaminophen occurs, a large current value change based on the reduction reaction of hydrogen peroxide on the electrode takes precedence. Was observed. On the other hand, when +0.6 V in Comparative Example 6 was applied (dotted line), the interfering substances ascorbic acid, uric acid, and the like were more effective than the change in the current value based on the oxidation reaction of the target hydrogen peroxide on the electrode. The change in current value due to the oxidation reaction of acetoaminophen was more prominently observed.

[0057] This is because fluorine can be used as a detection electrode material for constructing a biosensor capable of selectively measuring a test substance by simply selecting and applying an appropriate potential and avoiding the influence of interfering substances. It shows that the use of contained CNTs is extremely effective.

Industrial applicability

[0058] The biosensor of the present invention detects or detects a test substance contained in a sample without being affected by an electrochemically active substance such as a reducing interfering substance, as compared with a conventional biosensor. Since it can be quantified and has excellent detection sensitivity, it can be used as a biosensor for medical diagnosis or health diagnosis.

Claims

The scope of the claims

[I] A biosensor having a detection electrode, wherein the detection electrode material is a carbon nanotube containing boron.

[2] The carbon nanotube is a multi-walled carbon nanotube having a diameter of less than lOOnm.

The biosensor according to 1.

[3] The biosensor according to claim 1 or 2, wherein the biosensor is used in the form of a paste mixed with boron-containing carbon nanotube force S mineral oil, ionic liquid, or polymer binder resin.

[4] The biosensor according to claim 1 or 2, wherein the carbon nanotube containing boron is used in a state dispersed in water or an organic solvent.

5. The biosensor according to claim 3, wherein the detection electrode is a cylindrical electrode filled with a carbon nanotube prepared in a paste form in a cylindrical container.

6. The biosensor according to claim 3 or 4, wherein the detection electrode comprises a carbon nanotube containing boron on an insulating substrate.

7. The biosensor according to claim 3 or 4, wherein the detection electrode is a carbon electrode, platinum electrode, gold electrode or silver electrode on which carbon nanotubes containing boron are arranged.

[8] The biosensor according to [6], which is a carbon nanotube disposed on an insulating substrate by S-screen printing using boron-containing carbon nanotube force.

9. The biosensor according to any one of claims 1 to 8, wherein the detection electrode is an electrode in which an enzyme is immobilized on the electrode.

10. The biosensor according to claim 9, wherein the detection electrode is an electrode in which a single mediator molecule is held on the electrode.

11. The biosensor according to claim 10, wherein [I I] is a mediator monomolecular molecule monolayer.

[12] Claims;! To 11 of! / 11, which avoid the influence of measurement interfering substances by setting the interelectrode voltage to a specific voltage, and enable selective measurement of the target substance. Biosensor.

[13] A method for detecting or quantifying a test substance in a sample using the biosensor according to any one of claims 1 to 12, wherein the electrode voltage is applied after the sample is brought into contact with the detection electrode. specific A method characterized in that the voltage is set and applied.