JP2000081409A - Enzyme electrode and biosensor or measuring instrument using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an enzyme electrode or the like that is excellent in long- term stability and usable under a wide range of measuring conditions. SOLUTION: This enzyme electrode has an electrode 2 provided on an insulating substrate 1 and functioning as a working electrode, and a bonding layer 3 composed chiefly of γ-aminopropyl triethoxysilane is formed thereover. Further, a fixed enzyme layer 4 in which an enzyme having a catalytic function is fixed in an organic high polymer and a limited permeation layer 5 made of a fluoroalcohol ester layer of a methacrylic acid resin are sequentially formed over the bonding layer 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an enzyme electrode for electrochemically measuring a specific chemical substance in a solution using an enzyme reaction, and to a biosensor and a measuring instrument using the same.

[0002]

2. Description of the Related Art As a method for measuring various components contained in a biological sample or the like, a measurement method combining an enzyme reaction and an electrochemical reaction is widely used. For example, a biosensor that converts a chemical substance in a solution into hydrogen peroxide by a catalytic function of an enzyme and measures the hydrogen peroxide by a redox reaction has been widely used. For example, a glucose biosensor
Glucose is oxidized by glucose oxidase (GOX) to form gluconolactone and hydrogen peroxide. Since the generated hydrogen peroxide is proportional to the glucose concentration,
By measuring the amount of generated hydrogen peroxide, the amount of glucose in the sample is determined.

In this type of sensor, a layer that restricts the transmission of a chemical substance to be measured (hereinafter referred to as a restricted transmission layer)
Is generally formed on the outermost layer of the sensor electrode portion. FIG. 9 shows an enzyme electrode having such a structure, in which an electrode 2 functioning as a working electrode is provided on an insulating substrate 1, and a bonding layer 3 and an enzyme having a catalytic function are placed on the electrode 2 in an organic polymer. Immobilized immobilized enzyme layer 4 and restricted permeation layer 5
Are sequentially formed. By providing such a restricted transmission layer, excessive diffusion of the chemical substance to be measured is restricted, and the measurement range can be expanded to a certain high concentration. Further, it is possible to prevent the immobilized enzyme layer from directly coming into contact with urine, blood, or the like, which is a subject, and to avoid a decrease in performance due to adhesion of proteins and the like and decomposition of enzymes. Here, as the material of the restricted transmission layer, conventionally, polyalkylsiloxane (JP-A-10-26601), silicone (JP-A-6-242068) and the like have been used.

As an example of providing a restricted transmission layer having a structure different from that described above, there is a technique described in Japanese Patent Application Laid-Open No. Sho 59-22620. In this case, a membrane made of Teflon (registered trademark, polytetrafluoroethylene) or a membrane made of polyvinylidene fluoride provided with pores as a restricted permeation layer is attached so as to cover the electrodes.

Further, US Pat. No. 5,696,314 discloses an enzyme electrode in which a porous restricted permeation layer containing Teflon particles or the like is formed on an immobilized enzyme layer. In this enzyme electrode, as shown in FIG. 11, an electrode 31 made of platinum or the like is formed on a substrate 30, and an immobilized enzyme layer 32 is formed thereon. Then, a polymer layer 34 containing the same enzyme as the enzyme contained in the immobilized enzyme layer 32 is formed thereon via an adhesive layer 33. Further on that,
A restricted transmission layer 35, an adhesive layer 36, and a protective layer 37 are formed.

[0006] In the above-mentioned US patent, there is disclosed an example in which the restricted permeation layer 35 is porous, and contains polymer particles, metal particles, and a polymer binder as essential components, and uses Teflon as a material of the polymer particles and the polymer binder. I have. The restricted transmission layer 35 is formed using a screen printing method. That is, first, a Teflon binder is dissolved in a fluorine-containing solvent, and then alumina particles, Teflon particles, and the like are mixed and kneaded with the ink (roll mil).
led). Screen printing of the prepared ink (stenciled)
By doing so, the restricted transmission layer 35 is formed.

[0007]

However, the above-mentioned prior art has the following problems.

First, the problem in the case where polyalkylsiloxane or silicone is used as the material of the restricted permeation layer will be described. When such a material is used, there is a problem that durability for long-term use is not always sufficient. This is due to the insufficient strength of the restricted transmission layer. The enzyme electrode has a structure in which organic materials that swell in a solution, such as an immobilized enzyme film, are stacked. Therefore, if the strength of the restricted transmission layer is insufficient, cracks or the like occur without being able to withstand such swelling of the thin film. For this reason, the enzyme electrode may be damaged when used for a long time.

Further, when measuring a sample containing a high concentration of contaminants, the sensor output may be significantly reduced when the measurement is performed over a long period of time. This is due to the fact that the contaminants adhere to the restricted permeation layer itself, and the original restricted permeability is reduced. Particularly, in the case of body fluid, since a substance such as a urea compound other than protein adheres to the limited permeation layer itself, the restricted permeability is significantly reduced.

Further, when the measurement density range is expanded to a high density, the response speed sometimes becomes slow. This is because when a sample containing a high concentration of a substance to be measured is analyzed, when a conventionally used restricted permeation layer is used, the thickness must be increased due to the limit of permselectivity. This is because it takes time for the diffusion speed in the inside to stabilize.

A technique using a membrane made of Teflon or a membrane made of polyvinylidene fluoride (JP-A-59-22620).
Had the following problems.

[0012] A method using a filter using Teflon or the like has been conventionally used, but it is usually used in such a manner that the filter is disposed outside the enzyme electrode so as to cover the enzyme electrode.
As is clear from the molecular structure, the fluorine compound has poor adhesion to other organic polymer layers such as the immobilized enzyme layer, so that it is difficult to form the fluorine compound integrally with the immobilized enzyme layer. is there. JP-A-59-22620 only discloses a configuration in which a membrane made of the above-mentioned fluorine compound is attached to the tip of an enzyme electrode, and also discloses a configuration in which the membrane is bonded to and integrated with the electrode surface. Not.

Therefore, in the above-mentioned prior art, a certain gap is generated between the restricted transmission layer and the electrode surface.
There is a problem that it takes a long time for the target substance to reach the electrode surface and the response speed is slow, and a long time is required for cleaning and a re-measurement time is long.

Further, in order to impart a limited permeability, the restricted permeation layer using the above-mentioned fluorine compound needs to be provided with a hole of 10 to 100 μm and to have a certain thickness. For this reason, there is a problem that the response speed is slow, and a long time is required for cleaning, and the re-measurement time is long.

[0015] Furthermore, since the restricted permeation layer using the fluorine compound lacks flexibility, there is a problem that when the layer disposed on the electrode side of the restricted permeation layer swells, it is easily broken. In particular, this problem becomes remarkable when it is arranged adjacent to the swellable enzyme-immobilized layer.

On the other hand, US Pat. No. 5,696,314 discloses a structure in which a restricted transmission layer containing Teflon particles and a Teflon binder is integrally formed on an electrode.

However, as described above, when a polymer having a high fluorine content such as Teflon is used for the restricted permeation layer, the adhesion to an adjacent polymer layer such as an immobilized enzyme layer is inferior as described above. Therefore, even if the restricted permeation layer is formed integrally with the immobilized enzyme layer and the like, the adhesive force at the interface between these layers is not sufficient. In addition, since the restricted transmission layer using Teflon lacks flexibility, when the adjacent layer swells, it cannot sufficiently follow the swelling. Therefore, there is a problem that peeling easily occurs between the restricted permeation layer and an adjacent layer such as the immobilized enzyme layer during use.
Once peeling occurs, a certain gap will be created between the restricted transmission layer and the electrode surface, and it takes time for the target substance to reach the electrode surface, and the response speed is reduced.
There is a problem that a long time is required for cleaning and a re-measurement time is prolonged.

When Teflon or the like disclosed in the above publication is used, it is difficult to adjust the solution because of insufficient solubility in a solvent. For this reason, it is difficult to form a layer by a technique such as spin coating, and it is difficult to reduce the thickness of the restricted transmission layer. In addition, since the restricted permeation layer using the above-mentioned fluorine compound expresses the restricted permeability by being porous, it is necessary to ensure a certain thickness of the film. The above-mentioned U.S. Patent Publication states that a thickness of 10 to 40 [mu] m is preferable. As described above, since the restricted transmission layer has to be thick, the response speed is slow, and
There was a problem that a long time was required for cleaning.

Further, as described above, since the restricted permeation layer using Teflon lacks flexibility, the restricted permeation layer is easily damaged by swelling of an adjacent layer, and there is still room for improvement in this respect. In particular, this problem becomes remarkable when it is arranged adjacent to the swellable enzyme-immobilized layer.

The present invention solves the above-mentioned problems of the prior art, and can measure under a wide range of use conditions, and has an enzyme electrode having good durability for long-term use, a biosensor using the same, and a measurement method. The purpose is to provide a vessel.

Incidentally, although it is not an example of use as a constituent material of the restricted permeation layer, there are the following conventional techniques using a fluorine compound.

The use of a fluorine compound film (Teflon film) having a thickness of about 10 to 50 μm as an oxygen permeable film has been widely used, and is disclosed in, for example, Japanese Patent Application Laid-Open No. 56-73342. However, this is usually disposed between the immobilized enzyme layer and the electrode, not disposed above the immobilized enzyme layer, and does not have the function of a restricted permeation layer.

It is also known to dispose a Nafion membrane, which is an ion exchange resin, above the immobilized enzyme layer, which is disclosed, for example, in JP-A-8-50112.
Nafion is a cation exchange resin and has a structure in which a perfluoropolyalkylene ether side chain having a terminal sulfonic acid group is bonded to a perfluoromethylene main chain (formula (1)).

[0024]

Embedded image By arranging the Nafion membrane on the upper part of the immobilized enzyme layer, the reverse diffusion of hydrogen peroxide can be suppressed, the change over time in the response value to glucose after reaching the peak value can be suppressed, and the response characteristics can be improved. . However, since it has a terminal sulfonic acid group, the function of the restricted permeation layer cannot be sufficiently obtained. The ion exchange resin is intended to prevent the permeation of ionic interfering substances that interfere with the electrode reaction, and has almost no function of restricting permeation of excessive glucose and the like.

[0025]

According to the present invention for solving the above-mentioned problems, an electrode provided on an insulating substrate, an immobilized enzyme layer formed on the electrode, and an immobilized enzyme layer Having a restricted permeation layer formed on the top, the restricted permeation layer,
There is provided an enzyme electrode mainly comprising a polymer in which a pendant group containing at least a fluoroalkylene block is bonded to a fluorine-free vinyl polymer.

That is, the enzyme electrode of the present invention comprises an electrode (electrode layer) provided on an insulating substrate and a plurality of layers having various functions provided on the electrode.

The polymer constituting the restricted permeation layer is a fluoroalkylene block (fluoroalkylene unit)
Has a pendant group containing Therefore, adhesion of contaminants such as proteins and urea compounds is suppressed, and an enzyme electrode exhibiting stable output characteristics even when used for a long time can be obtained. Further, since the fluoroalkylene does not dissolve in most non-fluorinated solvents and detergents such as surfactants, an enzyme electrode having good chemical resistance can be obtained.

Further, since the main chain of this polymer is a vinyl polymer containing no fluorine, it has good adhesion to other organic polymer layers such as an immobilized enzyme layer. Therefore, there is no gap between the immobilized enzyme layer or the like formed on the electrode surface and the restricted permeation layer. Therefore, the response speed can be increased and the time required for cleaning can be reduced. In addition, due to the good adhesion, the durability of the layer structure is improved, and an enzyme electrode that is less likely to be damaged even when used for a long time can be obtained. Here, in addition to the pendant group containing the fluoroalkylene block, another appropriate side chain or functional group may be bonded. For example, -OH group, -CO
By having a functional group having an appropriate polarity such as an OH group, the adhesion to another organic polymer layer such as an adjacent immobilized enzyme layer can be further enhanced.

Further, the polymer constituting the restricted permeation layer has a specific structure in which a pendant group containing at least a fluoroalkylene block is bonded to a fluorine-free vinyl polymer. When used for such purposes, it shows good limited permeability. For this reason, the measurement concentration range can be greatly expanded. Further, since the limited permeability is good, the thickness of the limited transmission layer can be reduced, for example, the layer thickness can be 0.1 μm or less. Therefore, the response speed can be increased and the time required for cleaning can be reduced.

The above-mentioned restricted transmission layer is capable of producing a uniform thin film by a simple process such as a dipping method, a spin coating method and a spraying method, and is excellent in mass productivity.

Further, according to the present invention, an electrode provided on an insulating substrate, an immobilized enzyme layer formed on the electrode, and a restricted permeation layer formed on the immobilized enzyme layer are included. An enzyme electrode is provided, wherein the restricted transmission layer mainly comprises a fluoroalcohol ester of polycarboxylic acid (A).

According to the present invention, an electrode provided on an insulating substrate, an immobilized enzyme layer formed on the electrode, and a restricted permeation layer formed on the immobilized enzyme layer The enzyme electrode, wherein the restricted permeation layer comprises a fluoroalcohol ester of polycarboxylic acid (A) and an alkyl alcohol ester of polycarboxylic acid (B).

Further, according to the present invention, there are provided an electrode provided on an insulating substrate, an immobilized enzyme layer formed on the electrode, and a restricted permeation layer formed on the immobilized enzyme layer. And an enzyme electrode, wherein the restricted permeation layer mainly comprises a polycarboxylic acid ester compound having an alkyl alcohol ester group and a fluoro alcohol ester group.

These enzyme electrodes are composed of an electrode (electrode layer) provided on an insulating substrate and a plurality of layers having various functions provided on the electrode.
It is characterized by being composed of a polymer having a specific structure.

The enzyme electrode of the present invention uses a fluoroalcohol ester of polycarboxylic acid as a constituent material of the restricted permeation layer. Here, the fluoroalcohol ester of polycarboxylic acid is obtained by esterifying a part or all of the carboxyl groups of polycarboxylic acid with fluoroalcohol. Fluoroalcohol is one in which all or at least one of the hydrogen atoms in the alcohol is replaced with fluorine.

Since the constituent material of the restricted permeation layer has a fluoroalcohol ester group, adhesion of contaminants such as proteins and urea compounds is suppressed, and an enzyme electrode showing stable output characteristics even when used for a long time can be obtained. Can be Also, because the fluoroalcohol ester groups are not soluble in most non-fluorinated solvents or detergents such as surfactants,
An enzyme electrode having good chemical resistance can be obtained.

These enzyme electrodes use a polymer having a polycarboxylic acid main chain in the restricted permeation layer. Further, a fluoroalcohol is bonded to the main chain via an ester group. Therefore, the adhesiveness with other organic polymer layers such as the immobilized enzyme layer is good, and no gap is formed between the immobilized enzyme layer or the like formed on the electrode surface and the restricted permeation layer. Therefore, the response speed can be increased and the time required for cleaning can be reduced. In addition, due to the good adhesion, the durability of the layer structure is improved, and an enzyme electrode that is less likely to be damaged even when used for a long time can be obtained. Here, an appropriate functional group other than the fluoroalcohol ester group may be bonded to the main chain composed of the polycarboxylic acid. By having a functional group having an appropriate polarity, the adhesion to another organic polymer layer such as an adjacent immobilized enzyme layer can be further enhanced.

Furthermore, the polymer constituting the above-mentioned restricted permeation layer has a specific structure in which a part or all of the carboxyl group of the polycarboxylic acid is esterified with a fluoroalcohol. If so, the measurement concentration range can be greatly expanded. In addition, since the restricted permeability is good, it is possible to reduce the thickness of the restricted transmission layer. For example, the layer thickness can be 0.1 μm or less. Therefore, the response speed can be increased and the time required for cleaning can be reduced.

The above-mentioned restricted transmission layer is capable of producing a uniform thin film by a simple process such as a dipping method, a spin coating method and a spraying method, and is excellent in mass productivity.

Further, the restricted permeation layer is formed of a composition comprising a fluoroalcohol ester of polycarboxylic acid (A) and an alkyl alcohol ester of polycarboxylic acid (B), or an alkyl alcohol ester group and a fluoro alcohol ester group. When the composition is mainly composed of a polycarboxylic acid ester compound, the advantage that the stability at high temperatures is improved in addition to the above-described effects is obtained. Enzyme electrodes and biosensors containing them are sometimes stored and used at relatively high temperatures (eg, about 40 ° C.). After leaving a normal enzyme electrode at high temperature,
When used for measurement, the measurement sensitivity often fluctuated significantly compared to when measured before standing. On the other hand, the enzyme electrode and the biosensor provided with the restricted permeation layer having the above-described configuration have almost no change in the measurement sensitivity even when left at a high temperature,
Excellent stability.

In the enzyme electrode of the present invention described above, the electrode and the immobilized enzyme layer may be formed so as to be in direct contact with each other, or another layer may be interposed between them.
For example, an ion exchange resin mainly composed of an ion exchange resin having a perfluorocarbon skeleton between the electrode and the immobilized enzyme layer or between the electrode and the immobilized enzyme layer. A configuration having a resin layer may be employed. Similarly, the immobilized enzyme layer and the restricted permeation layer may be formed so as to be in direct contact with each other, or another layer may be interposed between them.

According to the present invention, there is provided a biosensor using the above enzyme electrode as a working electrode. Since this biosensor has a limited permeation layer made of a polymer having the above-mentioned specific structure on the surface of the enzyme electrode, it has excellent long-term stability and can be used under a wide range of measurement conditions.

Further, according to the present invention, there are provided various measuring instruments using the biosensor. That is, according to the present invention, there is provided a measuring instrument comprising: the biosensor; and a data notifying unit for notifying an electric signal obtained from the biosensor.

Also, the biosensor, an electrochemical measurement circuit for obtaining an electric signal from the biosensor, a data processing unit for calculating a measured value based on the electric signal, and a data notification for notifying the measured value And a measuring device comprising:

Since these measuring instruments have a biosensor having a working electrode of a specific structure, they have excellent long-term stability and can be used under a wide range of measuring conditions.
In addition, the operation method is simple, and even a person unfamiliar with the device can easily handle it.

Further, according to the present invention, a step of forming an electrode on an insulating substrate, and a step of applying a first liquid containing an enzyme to the electrode directly or via another layer, followed by drying and fixing A step of forming an immobilized enzyme layer, and a polymer in which a pendant group containing at least a fluoroalkylene block is bonded to a fluorine-free vinyl polymer directly or via another layer to the immobilized enzyme layer. Applying a second liquid containing the second liquid, followed by drying to form a restricted permeation layer.

In this method for producing an enzyme electrode, a restricted liquid layer is formed by applying and drying a second liquid containing a polymer having a specific structure as described above. For this reason, stability at the time of repeated measurement, adhesion to adjacent layers, durability,
It is possible to form a limited transmission layer having excellent limited permeability and the like with good film thickness controllability. Further, since the second liquid has a low viscosity, the restricted transmission layer can be easily formed with a small film thickness. Specifically, 0.01 to 3 after drying.
A limited transmission layer of μm can be formed satisfactorily.

[0048]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, "enzyme electrode" refers to an electrode provided with an immobilized enzyme layer. "Biosensor" refers to the element portion including the enzyme electrode,
A counter electrode and a reference electrode are included as necessary. Also,
The “measuring device” in the present invention refers to a system including the above-described biosensor, and includes various means for notifying and processing an electric signal obtained from the biosensor. Hereinafter, the enzyme electrode, the biosensor, and the measuring device according to the present invention will be described in detail.

The first enzyme electrode according to the present invention comprises an electrode provided on an insulating substrate, an immobilized enzyme layer formed on the electrode, and a restriction enzyme formed on the immobilized enzyme layer. And a permeable layer, wherein the restricted permeable layer is mainly composed of a polymer in which a pendant group containing at least a fluoroalkylene block is bonded to a fluorine-free vinyl polymer.

"Predominantly" means that the above-mentioned polymer is the main component constituting the restricted permeation layer. For example, when the content of the above polymer in the restricted permeation layer is 5%
0% by weight or more.

Here, the “vinyl polymer containing no fluorine” is a portion having a role of improving the adhesion to other organic polymer layers such as an immobilized enzyme layer, and therefore, particularly, the structure is restricted. But should not contain fluorine.
If fluorine is contained in the polymer portion excluding the pendant group, the adhesion to other organic polymer layers such as the immobilized enzyme layer will be reduced, and it will be difficult to adjust the solution. It becomes difficult.

The vinyl polymer containing no fluorine is a polymer having a main skeleton consisting of carbon-carbon bonds. Preferred examples thereof include unsaturated hydrocarbons, unsaturated carboxylic acids,
And a homopolymer or a copolymer of one or more monomers selected from the group consisting of unsaturated alcohols. Of these, polycarboxylic acids are particularly preferred. By selecting such a polymer, adhesion to other organic polymer layers such as an immobilized enzyme layer becomes particularly good, and a restricted permeation layer having excellent durability can be obtained. Further, it is preferable that a fluoroalkylene block is bonded to the vinyl polymer via an ester group. Since the ester group has an appropriate polarity, adhesion to other organic polymer layers such as an immobilized enzyme layer is further improved. Examples include 1H, 1H-perfluorooctyl polymethacrylate and 1H, 1H, 2H, 2H-perfluorodecyl polyacrylate.

The pendant group containing a fluoroalkylene block refers to a pendant group containing a fluoroalkylene as a constituent unit. Fluoroalkylene refers to an alkylene group in which some or all of the hydrogen atoms have been substituted with fluorine. The fluorine content of the pendant group, that is, x where the number of fluorine atoms contained in the pendant group is x and the number of hydrogen atoms contained in the pendant group is y
The value of / (x + y) is preferably from 0.3 to 1, more preferably from 0.8 to 1. By doing so, the adhesion of contaminants to the restricted permeation layer is suppressed, and good restricted permeability is obtained.

The number of carbon atoms of the pendant group is preferably 3 to
15, more preferably 5 to 10, most preferably 8 to 10. By doing so, the length of the pendant group becomes appropriate, good film-forming properties and limited permeability are obtained, and good adhesion to the adjacent polymer layer is maintained.

The binding ratio of the pendant group to the vinyl polymer, that is, the content of the pendant group is not particularly limited, and may be an appropriate value depending on other polymer layer materials and applications. For example, 0.1 to 30%. By setting the content ratio of the pendant group having water repellency in an appropriate range in this manner, good limited permeability and good adhesion to the adjacent polymer layer can be obtained. Here, the binding ratio of the pendant group means a ratio of the pendant group to all the groups bonded to the carbon-carbon bond serving as the main skeleton of the vinyl polymer. For example, when the vinyl polymer serving as the main chain is polyacrylic acid and 10% of the -COOH groups are esterified to form pendant groups, -COO
2.5% obtained by multiplying 25% of the bonding ratio of the H group by 10% of the esterification ratio is the bonding ratio of the pendant group.

The molecular weight of the polymer constituting the restricted permeation layer is preferably from 1,000 to 50,000, more preferably from 3,000 to 30,000. If the molecular weight is too large, it is difficult to adjust the solution, and it is difficult to make the restricted permeation layer thinner. If the molecular weight is too small, sufficient restricted permeability cannot be obtained. Here, the molecular weight refers to a number average molecular weight, which is measured by GPC (Gel Permiation Chromatography).

[0057] The second enzyme electrode according to the present invention comprises an electrode provided on an insulating substrate, an immobilized enzyme layer formed on the electrode, and a restriction enzyme formed on the immobilized enzyme layer. And a permeable layer, wherein the restricted permeable layer comprises a polycarboxylic acid (A)
Characterized by being mainly composed of a fluoroalcohol ester of Here, “mainly” means that the polymer is a main component constituting the restricted permeation layer, for example, that the content of the polymer with respect to the restricted permeation layer is 50% by weight or more.

Further, a third enzyme electrode according to the present invention comprises an electrode provided on an insulating substrate, an immobilized enzyme layer formed on the electrode, and an immobilized enzyme layer formed on the immobilized enzyme layer. Wherein the restricted transmission layer comprises a fluoroalcohol ester of the polycarboxylic acid (A) and an alkyl alcohol ester of the polycarboxylic acid (B).

The fourth enzyme electrode according to the present invention comprises an electrode provided on an insulating substrate, an immobilized enzyme layer formed on the electrode, and an immobilized enzyme layer formed on the immobilized enzyme layer. Characterized in that the restricted transmission layer mainly comprises a polycarboxylic acid ester compound having an alkyl alcohol ester group and a fluoro alcohol ester group. Here, “mainly” means that the polymer is a main component constituting the restricted permeation layer, for example, that the content of the polymer with respect to the restricted permeation layer is 50% by weight or more.

The polycarboxylic acids (A) and (B) and the polycarboxylic acid constituting the above polycarboxylic acid ester compound are polymers having a structural unit of a carboxylic acid such as acrylic acid, methacrylic acid, fumaric acid and itaconic acid. Say. For example, polymethacrylic acid, polyacrylic acid, a copolymer thereof, or the like can be given. The polycarboxylic acid (A) and the polycarboxylic acid (B) may be the same or different.

When the number of fluorine atoms contained in the fluoroalcohol ester group is x and the number of hydrogen atoms is y, x
The fluorine content of the fluoroalcohol ester group represented by / (x + y) is preferably 0.3 to 1, more preferably 0.8 to 1. By doing so, the adhesion of contaminants to the restricted permeation layer is suppressed, and good restricted permeability is obtained.

The number of carbon atoms of the fluoroalcohol constituting the fluoroalcohol ester is preferably 3 to 15, more preferably 5 to 10, and most preferably 8 to 10.
And By doing so, the length of the pendant group becomes appropriate, good film-forming properties and limited permeability are obtained, and good adhesion to the adjacent polymer layer is maintained.

The esterification rate of the fluoroalcohol ester of the polycarboxylic acid is not particularly limited, and can be an appropriate value according to other polymer layer materials and applications. For example, 0.1 to 30%. The esterification ratio refers to a ratio at which the carboxyl group of the main chain polyacrylic acid is esterified. By setting the esterification rate in the above range, the content of the fluoroalcohol ester group having water repellency becomes appropriate, and good restricted permeability and good adhesion to the adjacent polymer layer can be obtained.

In the present invention, the fluoroalcohol constituting the fluoroalcohol ester is preferably a primary alcohol. This is because adhesion of contaminants to the restricted transmission layer is effectively suppressed, and high chemical resistance to acids, alkalis, and various organic solvents can be obtained. For example, polymethacrylic acid 1H, 1H-perfluorooctyl or polyacrylic acid 1H, 1H, 2H, 2H-
Perfluorodecyl can be preferably used.

The restricted permeation layer has a structure containing a fluoroalcohol ester of polycarboxylic acid (A) and an alkyl alcohol ester of polycarboxylic acid (B), or has an alkyl alcohol ester group and a fluoro alcohol ester group. When the composition is mainly composed of a polycarboxylic acid ester compound, an enzyme electrode having good high-temperature stability can be obtained.

The preferred form of the “fluoroalcohol ester” is as described above.

The alkyl alcohol in the alkyl alcohol ester portion means a chain or cyclic alcohol represented by C _n H _{n + 2} OH (n is a natural number). n is an integer of 1 or more, preferably 2 to 10, more preferably 4
-8, most preferably 6. For example, a hexyl group, a cyclohexyl group and the like are preferably used. By doing so, the stability when the enzyme electrode is left at a high temperature is further improved.

In the case where the restricted permeation layer is composed of a fluoroalcohol ester of polycarboxylic acid (A) and an alkyl alcohol ester of polycarboxylic acid (B), the polycarboxylic acid (A) for the restricted permeation layer Is preferably 50 to 50%.
99% by weight, more preferably 75-99% by weight, most preferably 80-95% by weight. If the content is too low, the durability of the restricted transmission layer may decrease. On the other hand, if the content is too high, sufficient stability when left at high temperatures may not be obtained. On the other hand, the content of the alkyl alcohol ester of the polycarboxylic acid (B) in the restricted permeation layer is preferably 1 to 50% by weight, more preferably 1 to 2% by weight.
5% by weight, most preferably 5-20% by weight. If the content is too low, sufficient stability when left at high temperatures may not be obtained. If the content is too high, the durability of the restricted transmission layer may decrease. The alkyl alcohol ester of the polycarboxylic acid (B) is obtained by esterifying at least a part of the polycarboxylic acid (B) with the above-mentioned alkyl alcohol, and preferred examples include polyhexyl methacrylate. .

In the case where the restricted permeation layer is constituted by using a polycarboxylic acid ester compound having an alkyl alcohol ester group and a fluoro alcohol ester group, the preferred forms of each ester group are as described above, and various combinations of the ester groups are mentioned above. Things can be adopted. Although the ratio of the alkyl alcohol ester group to the fluoro alcohol ester group is not particularly limited, a / a where the number of fluoro alcohol ester groups in the ester compound is a and the number of alkyl alcohol ester groups is b.
The value of b is preferably 50 / 50-99 / 1, more preferably 75 / 25-99 / 1, most preferably 80/2.
0 to 95/5.

Examples of such polycarboxylic acid ester compounds include, for example, compounds having a repeating unit represented by the following formula (2). If the COO-R group is polyhexyl methacrylate, high-temperature stability is particularly improved. In addition, the limited permeability becomes good.

[0071]

Embedded image (N is an integer of 2 or more, X is an integer of 0 or more, Y is an integer of 1 or more.) As such a compound, a copolymer of 1H, 1H-perfluorooctyl methacrylate and cyclohexyl methacrylate, or , Acrylic acid 1H, 1H, 2H, 2H
-A copolymer of perfluorodecyl and cyclohexyl methacrylate. For example, a compound having a repeating unit of 1H, 1H, 2H, 2H-perfluorodecyl acrylate and cyclohexyl methacrylate, such as the following formula (3), is preferably used.

[0072]

Embedded image (N represents an integer of 2 or more.) The use of the above-described copolymer particularly improves high-temperature stability and also improves other characteristics such as a limited permeability layer.

As described above, the restricted permeation layer of the enzyme electrode of the present invention is composed of a polymer having a specific structure, but may be composed of a mixture of two or more polymers having different structures and different molecular weights.

In the enzyme electrode described above, the molecular weight of the polycarboxylic acid ester compound having a fluoroalcohol ester, an alkyl alcohol ester group and a fluoroalcohol ester group of the polycarboxylic acid (A) constituting the restricted permeation layer is preferably 1,000. ~ 500
00, more preferably 3000 to 30,000.
If the molecular weight is too large, it is difficult to adjust the solution, and it may be difficult to reduce the thickness of the restricted permeation layer. If the molecular weight is too small, sufficient restricted permeability may not be obtained. Here, the molecular weight refers to a number average molecular weight.

In the above-described enzyme electrode, the thickness of the restricted permeation layer is preferably 0.01 to 3 μm, more preferably 0.01 to 1 μm, and most preferably 0.01 to 0.1 μm.
1 μm. With such a thickness, the response speed can be improved and the cleaning time can be shortened.

FIG. 10 shows an example of a sensor using the enzyme electrode of the present invention. In this example, an enzyme electrode is used as the working electrode 7 and a counter electrode 8 and a reference electrode 9 are further provided on a quartz substrate. The working electrode 7 and the counter electrode 8 are platinum electrodes, and the reference electrode 9 is a silver / silver chloride electrode. Above the working electrode 7, a binding layer 3 mainly composed of γ-aminopropyltriethoxysilane, an immobilized enzyme layer 4 in which an enzyme having a catalytic function is immobilized in an organic polymer, a fluoroalcohol ester layer of methacrylic acid resin Are formed successively. The working electrode 7, the counter electrode 8, and the reference electrode 9 are each electrically connected to a measurement system.

Although the figure shows an example of an amperometric type sensor, it goes without saying that the enzyme electrode of the present invention can also be applied to an ion sensitive field effect transistor type sensor.

The biosensor of the present invention is particularly effective when used as a urine glucose sensor for measuring glucose (urine glucose) in urine.

Regarding the lower limit of measurement of urine sugar, the prior art
mg / dl, whereas the sensor according to the present invention
Detection is possible up to 5 mg / dl. Since the conventional biosensor has a high S / N ratio, when measuring low-concentration glucose in a region of 50 mg / dl or less, the sensor output is buried in noise, and quantitative measurement is difficult. On the other hand, since the sensor of the present invention has a low S / N ratio, highly accurate measurement is possible even in a low concentration region. The urine sugar level of a healthy person is 2
Since it is 10 mg / dl, the significance of the improvement of the measurement sensitivity as described above is very large. According to the biosensor of the present invention, urine sugar in a region of 50 mg / dl or less can be quantitatively measured. This is because it is possible to measure the urine sugar of a person who satisfies the above condition, and to collect data useful for preventing diabetes.

Further, by using the sensor of the present invention, the effects of urea, vitamin C and acetaminophen contained in a large amount in urine can be effectively eliminated. Therefore, accurate measurement is possible even when a soft drink containing vitamin C is ingested or a fever-reducing agent containing acetaminophen is taken.

The measuring instrument of the present invention is preferably provided with a biosensor detachably. This is because the electrode portion of the biosensor is consumed by use, and thus it is desirable to have a structure that can be easily replaced. Here, in addition to the form in which only the biosensor part is detachable, a form in which the wiring for connecting the biosensor to another part and the part including the biosensor are detachable may be used. . For example, in the measuring instrument having the configuration shown in FIG. 16, the wiring 54 between the biosensor 50 and the electrochemical measurement circuit section 51 may be detachable.
The portion consisting of the wire 0, the wiring 54, and the electrochemical measurement circuit section 51 may be detachable.

The data processing unit in the measuring instrument of the present invention
It has a function of calculating a measured value based on an electric signal obtained from a biosensor, and operates, for example, in a form of converting the electric signal into an analog signal and / or a digital signal and calculating a measured value. I do. The data processing unit may be configured to include various means, for example,
(A) clocking means, (b) time setting means for setting a measuring time, and time notifying means for notifying that the time set by the time setting means has come, and (c) operation explanation for explaining a method of operating the measuring instrument. Means, (d) a measured value storing means for storing the calculated measured value, (e) a password registering means for registering a password of a user of the measuring instrument, (f) a memo registering means for registering a memo, (g) Operation notification means for detecting a malfunction of the measuring instrument,
(H) calibration time notification means for detecting and reporting the calibration time of the enzyme electrode; (i) electrode replacement time notification means for detecting and reporting the replacement time of the enzyme electrode; and (j) detecting and reporting an abnormal current value. It may be configured to include a part or all of the abnormal current value notifying means and (k) the electrode calibrating means for calibrating the enzyme electrode. With such a configuration, the operability is further improved. Here, the processing results obtained by one or more of the above (a) to (k) are reported by, for example, a reporting unit.

The method for producing an enzyme electrode of the present invention comprises the steps of forming an electrode on an insulating substrate, applying a first solution containing an enzyme to the electrode directly or via another layer, and then drying the solution. And forming an immobilized enzyme layer, and a pendant group containing at least a fluoroalkylene block is bonded to the fluorine-free vinyl polymer directly or via another layer to the immobilized enzyme layer. After applying the second liquid containing the polymer, followed by drying to form a restricted permeation layer. Regarding preferred embodiments and the like of "a polymer in which a pendant group containing at least a fluoroalkylene block is bonded to a vinyl polymer containing no fluorine", the first to fourth enzyme electrodes according to the present invention are described. As described in the section, for example, a fluoroalcohol ester of polycarboxylic acid is exemplified, and polymethacrylic acid 1
H, 1H-perfluorooctyl, polyacrylic acid 1
H, 1H, 2H, 2H-perfluorodecyl, or a copolymer of 1H, 1H-perfluorooctyl methacrylate and cyclohexyl methacrylate, acrylic acid 1
A copolymer of H, 1H, 2H, 2H-perfluorodecyl and cyclohexyl methacrylate, etc., may be mentioned.

Hereinafter, embodiments of the present invention will be further described with reference to the drawings.

(First Embodiment) This embodiment will be described with reference to FIG. In the enzyme electrode of the present embodiment, an electrode 2 functioning as a working electrode is provided on an insulating substrate 1,
A bonding layer 3 mainly composed of γ-aminopropyltriethoxysilane is formed thereon. Further thereon, an immobilized enzyme layer 4 in which an enzyme having a catalytic function is immobilized in an organic polymer, and a restricted permeation layer 5 made of a methacrylic acid resin fluoroalcohol ester layer are sequentially formed.

As the material of the insulating substrate 1, a material mainly composed of a material having a high insulating property such as ceramics, glass, quartz and plastic can be used. water resistant,
It is preferable that the material is excellent in heat resistance, chemical resistance, and adhesion to electrodes.

The material of the electrode 2 is, for example, platinum,
Those mainly composed of gold, silver, carbon and the like can be used, and among them, platinum excellent in chemical resistance and hydrogen peroxide detection characteristics is preferably used. The electrode 2 on the insulating substrate 1 is formed by sputtering, ion plating, vacuum deposition, chemical vapor deposition,
It can be formed by an electrolytic method or the like, of which a sputtering method is preferable. This is because the adhesion to the insulating substrate 1 is good, and the platinum layer can be easily formed. In order to improve the adhesion between the insulating substrate 1 and the electrode 2,
A titanium layer or a chromium layer may be interposed between them.

The bonding layer 3 formed on the electrode 2 improves the adhesion (bonding force) between the immobilized enzyme layer 4 thereon, the insulating substrate 1 and the electrode 2. In addition, the immobilized enzyme layer 4 on which the surface of the insulating substrate 1 is improved in wettability and the enzyme is immobilized.
There is also an effect of improving the uniformity of the film thickness when forming the film.
Furthermore, there is also selective permeability to ascorbic acid, uric acid and acetaminophen which interfere with the reaction of hydrogen peroxide at the electrode 2. The bonding layer 3 is mainly composed of a silane coupling agent. As the type of silane coupling agent,
Amino silane, vinyl silane, and epoxy silane are mentioned. Among them, γ-aminopropyltriethoxy silane, which is a kind of amino silane, is preferable from the viewpoint of adhesion and permselectivity. The bonding layer 3 can be formed, for example, by spin-coating a silane coupling agent solution. At this time, the silane coupling agent concentration was 1
It is preferable to be about v / v% (volume / volume%). This is because the selectivity is significantly improved.

The immobilized enzyme layer 4 is formed by immobilizing an enzyme having a catalytic function using an organic polymer as a base material. The immobilized enzyme layer 4 is formed by spin coating, for example, by dropping a solution containing various enzymes, a protein cross-linking agent such as glutaraldehyde, and albumin onto the binding layer 3. Albumin protects various enzymes from the reaction of a cross-linking agent and serves as a substrate for proteins. Enzymes include lactate oxidase, glucose oxidase, urate oxidase, galactose oxidase, lactose oxidase, sucrose oxidase, ethanol oxidase, methanol oxidase, starch oxidase, amino acid oxidase, monoamine oxidase, and cholesterol oxidase. The products of the catalytic reaction include enzymes that produce hydrogen peroxide or consume oxygen, such as enzymes, choline oxidase, and pyruvate oxidase.

Here, hydrogen peroxide may be produced by using two or more enzymes simultaneously. For example, creatininase, creatinase, and sarcosine oxidase correspond to this. By using these enzymes, creatinine can be detected. Further, an enzyme and a coenzyme may be used simultaneously. For example, 3-hydroxybutyrate dehydrogenase and nicotinamide adenine dinucleotide (NA
D) corresponds to this. The use of these enzymes allows the detection of 3-hydroxybutyric acid. Further, an enzyme and an electron mediator may be used simultaneously. In this case, the electron mediator reduced by the enzyme is oxidized on the electrode surface, and an oxidation current value obtained at this time is measured. For example, glucose oxidase and potassium ferricyanide correspond to this. The use of these makes it possible to detect glucose.

As described above, the immobilized enzyme layer 4 is not particularly limited as long as it has at least an enzyme and has a function of converting a substance to be measured into hydrogen peroxide or the like which is an electrode sensitive substance.

The method of forming the immobilized enzyme layer 4 is not particularly limited as long as it can form a uniform film thickness, and a screen printing method or the like can be used other than the spin coating method.

The fluoroalcohol ester of the methacrylic acid resin constituting the restricted permeation layer 5 is obtained by esterifying a part or all of the methacrylic acid resin with a fluoroalcohol. At least one has been replaced with fluorine. For example, polymethacrylic acid 1H, 1H
-Perfluorooctyl or polyacrylic acid 1H, 1H,
2H, 2H-perfluorodecyl can be used. In the present invention, for example, 1H, 1H-perfluorooctyl methacrylate refers to a polymer in which part or all of methacrylic acid is esterified with 1H, 1H-perfluorooctyl alcohol.

The restricted permeation layer 5 is prepared by dropping a methacrylic acid resin fluoroalcohol ester solution diluted with a perfluorocarbon solvent such as perfluorohexane onto the immobilized enzyme layer 4 on which an enzyme having a catalytic function is immobilized. Can be formed by spin coating.

The methacrylic acid resin fluoroalcohol ester concentration in the solution depends on the substance to be measured.
It is preferably set to about 5% by weight, more preferably about 0.3% by weight. This is because, as described later, by setting the content in this range, a good restricted permeability is exhibited (FIG. 6).

The method for forming the restricted transmission layer 5 is as follows.
There is no limitation as long as a layer having a uniform thickness can be obtained, and a spray coating method, a dipping method, or the like can be used in addition to the spin coating method.

When the enzyme electrode of this embodiment is used as a glucose sensor, the outermost restricted permeation layer 5 restricts the diffusion rate of glucose, and the organic polymer membrane 4 using glucose oxidase diffuses glucose. Catalytic reaction with oxygen produces hydrogen peroxide and gluconolactone. Of these, the concentration of glucose can be known by measuring the oxidation current when hydrogen peroxide reaches the electrode 2. In the case of a two-electrode method, an existing reference electrode is used from outside as an electrode system at the time of measurement. In the case of a three-electrode method, both the counter electrode and the reference electrode are immersed in the measurement solution at the same time.

(Second Embodiment) Next, this embodiment will be described with reference to FIG. In the enzyme electrode of the present embodiment, an electrode 2 functioning as a working electrode is provided on an insulating substrate 1, and a bonding layer 3 mainly composed of γ-aminopropyltriethoxysilane is formed thereon. And
Further thereon, an ion-exchange resin layer 6 mainly composed of a perfluorocarbon sulfonic acid resin (Nafion), an immobilized enzyme layer 4 in which an enzyme having a catalytic function is immobilized in an organic polymer, a fluoroalcohol ester of methacrylic acid resin The restricted transmission layers 5 composed of layers are sequentially formed.

The electrode 2 and the γ-aminopropyltriethoxysilane film 3 formed on the insulating substrate 1 are sequentially formed by the same method as in the first embodiment.

The ion-exchange resin layer 6 containing a perfluorocarbon sulfonic acid resin (Nafion) as a main component is prepared by dissolving a perfluorocarbon sulfonic acid resin prepared by dissolving in ethanol diluted with pure water to 50% with γ-aminopropyl triethoxy. It is dropped on the bonding layer 3 made of silane and formed by spin coating. As the solvent, for example, alcohols such as isopropyl alcohol and ethyl alcohol are used. The concentration of the perfluorocarbon sulfonic acid resin to be dropped is preferably 1 to 10 w / v%, more preferably 5 to 7 w / v%. This is because the effect of eliminating the influence of ascorbic acid which interferes with the electrode reaction of hydrogen peroxide becomes remarkable by setting the content in such a range.

(Third Embodiment) Next, this embodiment will be described with reference to the drawings. As shown in FIG. 3, the enzyme electrode of the present embodiment is provided with a working electrode 7, a counter electrode 8, and a reference electrode 9 on an insulating substrate 1, on which a bonding layer 3 mainly composed of γ-aminopropyltriethoxysilane is provided. Are formed. Further thereon, an immobilized enzyme layer 4 in which an enzyme having a catalytic function is immobilized in an organic polymer, and a restricted permeation layer 5 made of a methacrylic acid resin fluoroalcohol ester layer are sequentially formed. The material of the working electrode 7 and the counter electrode 8 is the electrode 2 in the first and second embodiments.
What is necessary is just the same as. The material of the reference electrode 9 is silver / silver chloride.

With such a configuration, the working electrode, the counter electrode,
Since the reference electrode is formed on one insulating substrate, the solution can be exchanged while driving the sensor. This is because, as long as the sensor surface is wet with the electrolyte or the like, the electrodes of the working electrode, the counter electrode, and the reference electrode are electrically connected, so that the measurement can be continued even if the sensor temporarily comes into contact with air.
In addition, accurate electrochemical measurement by the three-electrode method becomes possible,
In particular, it is possible to realize a minute current detection type enzyme electrode. Further, similarly to the second embodiment, γ-
It is also possible to form an ion exchange resin layer made of a perfluorocarbon sulfonic acid resin between the aminopropyltriethoxysilane membrane 3 and the immobilized enzyme layer 4.

(Fourth Embodiment) Next, this embodiment will be described with reference to the drawings. As shown in FIG. 4, the enzyme electrode of the present embodiment is provided with two working electrodes 7, one counter electrode 8 and one reference electrode 9 on an insulating substrate 1, and γ-aminopropyl on it. The bonding layer 3 mainly composed of triethoxysilane is formed. On the two working electrodes 7, immobilized enzyme layers 4 and 10 in which different types of enzymes are immobilized, respectively, are provided. Further, a restricted transmission layer 5 made of a methacrylic acid resin fluoroalcohol ester layer is further formed thereon. The materials of the working electrode 7 and the counter electrode 8 may be the same as those of the electrode 2 in the first and second embodiments. The material of the reference electrode 9 is preferably silver / silver chloride.

With such a configuration, a layer in which enzymes having different catalytic functions are immobilized on the two working electrodes is formed, and it is possible to simultaneously measure a plurality of specific sample components in the measurement sample.

(Fifth Embodiment) This embodiment shows an example of the method for producing an enzyme electrode according to the present invention.

First, a working electrode and a counter electrode made of platinum and a reference electrode made of silver / silver chloride are formed on a substrate made of quartz.

Next, the surface of each electrode and the surface of the substrate are cleaned. As a washing method, a method of washing with an organic solvent, an acid, or the like, a method of washing with an ultrasonic cleaner, and the like can be used in combination. As the organic solvent and the acid, those that do not damage the electrode material are used. As the organic solvent, a polar solvent is preferably used, and a ketone-based solvent such as acetone and an alcohol-based solvent such as isopropyl alcohol can be used. In addition, dilute sulfuric acid or the like is used as the acid. In addition, electrolytic cathode water can be used. Electrolytic cathode water refers to a liquid generated on the cathode side when pure water or the like is electrolyzed. Electrolytic cathode water has a high reducing property while being neutral to weakly alkaline, so that the potential of both the substrate surface and the surface of the adhered particles can be set to a negative potential while suppressing damage to the substrate and electrodes, and the desorbed particles Can be prevented from re-adhering. Of the above, for example, a method of sequentially washing with acetone and dilute sulfuric acid is preferably used.

Next, a coupling layer is formed on the surfaces of the working electrode, the counter electrode, and the reference electrode. As described above, a silane coupling agent such as γ-aminopropyltriethoxysilane is preferably used as a material constituting the bonding layer.

As a method of applying the coupling agent solution or the like,
A spin coating method, a spray method, a dipping method, a heated air flow method, or the like is used. The spin coating method is a method in which a liquid in which a constituent material of a bonding layer such as a coupling agent is dissolved or dispersed is applied by a spin coater. According to this method, a thin coupling layer can be formed with good film thickness controllability. The spray method is a method of spraying a coupling agent liquid or the like toward a substrate, and the dipping method is a method of dipping the substrate in the coupling agent liquid or the like. According to these methods, the bonding layer can be formed by a simple process without requiring a special device. The heated air flow method is a method in which a substrate is placed in a heated atmosphere and a vapor such as a coupling agent liquid flows through the substrate. According to this method as well, a thin coupling layer can be formed with good film thickness controllability.

After the application of the coupling agent solution or the like, drying is performed. The drying temperature is not particularly limited, but is usually room temperature (25
C) to 170C. The drying time is usually 0.5 to 24 hours, depending on the temperature. Drying may be performed in air, but may be performed in an inert gas such as nitrogen. For example, a nitrogen blowing method in which nitrogen is dried while spraying the substrate may be used.

After forming the binding layer, an enzyme solution is applied to form an immobilized enzyme layer. As a method for applying the enzyme solution, a spin coating method, a dipping method (immersion method) or the like is used, and among them, a spin coating method having excellent film thickness controllability is preferably used. After the application of the enzyme solution, drying is performed. The drying temperature is a temperature at which the activity of the enzyme is not impaired. Room temperature (25
C) to 40C. The drying time is 0.5 to 24 hours, depending on the temperature. Drying may be performed in air, but may be performed in an inert gas such as nitrogen. For example, a nitrogen blowing method in which nitrogen is dried while spraying the substrate may be used.

Next, a fluoroalcohol ester solution of polycarboxylic acid or the like is applied to form a restricted permeation layer. As a method of applying the solution, a spin coating method, a dipping method, a spray method, a brush coating method, or the like is used, and among them, a spin coating method having excellent controllability of the film thickness is preferably used. When the spin coating method is used, a restricted transmission layer composed of a thin film having a thickness of about 0.01 to 3 μm can be formed with good controllability. Alternatively, a method may be used in which coating is performed by a dipping method in which the substrate is immersed in the above volume, and then drying is performed while blowing nitrogen gas. According to this method, the restricted transmission layer can be formed by a simple method.

After the application of the above solution, drying is performed. The drying temperature is desirably in a range that does not impair the activity of the enzyme in the immobilized enzyme layer, and is preferably in the range of room temperature (25 ° C) to 40 ° C. The drying time is usually 0.5 to 24 hours, depending on the temperature. Drying may be performed in air, but may be performed in an inert gas such as nitrogen. For example, a nitrogen blowing method in which nitrogen is dried while spraying the substrate may be used.

As described above, an enzyme electrode having various layers having specific functions formed on the electrode is manufactured. In the present embodiment, for the working electrode, the counter electrode, and the reference electrode,
Although an example in which a binding layer, an immobilized enzyme layer, and a restricted permeation layer are provided has been described, the configuration of the present invention is not limited thereto. For example, a binding layer, an immobilized enzyme layer on a working electrode and a counter electrode, Provide a limited transmission layer, a binding layer on the reference electrode,
A protective layer for protecting the reference electrode can be sequentially laminated. In this embodiment, a biosensor including three working electrodes, a working electrode, a counter electrode, and a reference electrode, has been described. However, a working electrode made of platinum and a reference electrode may be provided on a quartz substrate.

(Sixth Embodiment) This embodiment shows an example of the measuring instrument of the present invention provided with a biosensor, an electrochemical measurement circuit section, a data processing section, and a data notification section. Hereinafter, description will be made with reference to FIGS. 16 and 17.

As shown in FIG. 16, this measuring instrument has a configuration in which a biosensor 50, an electrochemical measuring circuit section 51, a data processing section 52, and a data notifying section 53 are connected by a wiring 54.

As the biosensor 50, for example, one having the enzyme electrode described in the first to fourth embodiments can be used. Since the biosensor 50 is a consumable item, it is preferable that the biosensor 50 be a detachable type that can be easily replaced.

The electrochemical measurement circuit section 51 uses a potentiostat in this embodiment, but is not particularly limited as long as it can apply a constant potential to the biosensor 50 and measure a current value.

The data processing section 52 has the configuration shown in FIG. 17, and includes a clock section 60, a time setting section 61, a time notifying section 62, an operation explanation section 63, a measured value storage section 64,
PIN registering means 65, memo registering means 66, operation notifying means 67, calibration time notifying means 68, electrode replacement time notifying means 69, abnormal current value notifying means 70, and electrode calibrating means 71
Contains. Since the configuration includes the above-described units, the user of the measuring instrument can smoothly perform calibration, measurement, storage of measurement data, and the like of the electrodes. In the present embodiment, a personal computer (hereinafter, referred to as a personal computer) is used as the data processing unit 52. However, any data processing unit such as a microprocessor that can process signals from the electrochemical measurement circuit unit 51 is used. There is no particular limitation. The signal processed by the data processing unit 52 is converted into a measured value, and displayed by the data notifying unit 53 as the measured value.

Although the data notification unit 53 uses a display for a personal computer in this embodiment, the data processing unit 5
2 is not particularly limited as long as it has a function of notifying the data processed by step 2. The data processed by the data processing unit 52 includes the measurement value calculated by the data processing unit 52, the operation check and malfunction check of the biosensor 50, the abnormal current value detection result, the replacement time of the biosensor 50, the biosensor 50 calibration time and calibration procedure, date, time, clock, signal from the electrochemical measurement circuit unit 51 processed by the calculation unit of the data processing unit 52, operation means at the time of initial setting, and operation advice at the time of performing operation advice It is an operation explanation and the like. The means for informing is digital numerical value, analog numerical value, and voice. Other notification means include sound,
Light, vibration, color, light, graphics, and heat may be used, but digital numerical values and analog numerical values are preferably used.

The wiring 54 may be any electric wire that can connect them.

Next, each means (FIG. 17) included in the data processing section 52 will be described.

In this embodiment, the clock means 60 uses a clock built in the personal computer. However, the clock means is not particularly limited as long as it has a function of indicating time to the arithmetic unit.

The time setting means 61 is a function for setting the time to be measured using the time keeping means 60. In the present embodiment, a part of the function of a clock built in the personal computer is used similarly to the time measuring means 60, but the arithmetic unit has a function of indicating time and a function of setting a time to be measured further. If so, there is no particular limitation. It is preferable that a plurality of times can be set. This is convenient when it is desired to perform a plurality of measurements a day.
It is more convenient if the use of the time setting means 61 can be selected.

The time notifying means 62 has a function of notifying at the time set by the time setting means 61. For example, if the setting is made by the time setting means 61 to notify every 12 hours, the measurer can know the measurement time from the time notifying means 62 every 12 hours.

The operation explanation means 63 has a function for explaining the method of operating the measuring instrument of the present invention and the points to be noted when performing the operation. Whether or not the operation explanation means 63 is used can be appropriately selected by setting.

The measurement value storage means 64 is a means for storing the measurement values obtained by the measuring device and other information, and a RAM (random access memory) is preferably used as a semiconductor storage element. Preferably, the measurement value storage means 64 can store a plurality of measurements. The measured value storage means 64 can store not only measured values but also various information processed in the data processing unit 52. Information to be stored is appropriately limited by setting.

The personal identification number registration means 65 has a function of restricting the use of a measuring device other than a specific person and the information of the measured value, and having this function can protect the privacy of the user. Becomes The setting of the personal identification number is preferably a numerical value of four or more digits or an alphanumeric character in that high security can be secured. It is desirable that the password registration means 65 can register a plurality of passwords. In this way, the privacy of a plurality of users can be protected. In this embodiment, all information cannot be input / output unless a 4-digit password is entered. The use or non-use of the personal identification number registration means 65 can be appropriately changed by setting.

The memo registration means 66 includes a memo registration means capable of registering a memo, a memo item means for calling a registered memo group, a memo selection means for selecting a memo item to be registered from the called memo group, and a memo selection means. It is preferable to provide a memo calling means for calling the selected memo. In the present embodiment, such a configuration is employed, and for example, the weight, blood pressure, and body temperature at the time of measurement are registered as information of the measurer using the memo registration unit. Note that the memo registration means 6
6 can be changed as needed by setting.

The operation notifying means 67 is provided when the wiring 54 between the biosensor 50, the electrochemical measurement circuit section 51 and the data processing section 52 is disconnected or at least one of them is not connected. Has a function of notifying this. The use or non-use of the operation notifying means 67 can be appropriately changed by setting.

The calibration time notifying means 68 is provided for the biosensor 5.
This is a means for notifying the zero calibration time. When the enzyme electrode is used to a certain extent, calibration is required.
8 has a function of notifying the calibration time. The determination of the calibration time can be made based on the measurement time or the number of measurements. In the present embodiment, both or one of these can be set as a reference by setting.

The electrode replacement time notifying means 69 has a function of notifying the replacement time of the electrodes included in the biosensor 50. The determination of the replacement time can be made based on the measurement time, the number of measurements, the voltage drop of the battery, and the like. In this embodiment,
Depending on the setting, all or any one of them can be used as a reference.

The abnormal current value notifying means 70 outputs an abnormal current to the biosensor 50, the electrochemical measurement circuit section 51, the data processing section 52, and the wiring 54 connecting these elements, causing an unmeasurable state. This is a means for notifying that a part has been damaged.

The "notification" in the operation notifying means 67, the calibration time notifying means 68, the electrode replacement time notifying means 69, and the abnormal current value notifying means 70 is performed, for example, through the above-described data notifying section. The predetermined information is transmitted to the user of the measuring instrument.

The electrode calibrating means 71 is used at the time of initial use or at the time of calibration, and has a function of explaining a procedure for calibrating the biosensor 50 and calibrating the biosensor 50. The explanation of the calibration procedure and the like is performed via the calibration time notification means 68.

When the measuring instrument of the present embodiment is used, the service life of the biosensor, the calibration time, the operation procedure of the measuring instrument, and the like are displayed, so that even a person unfamiliar with the handling of the apparatus can easily measure with high accuracy. It can be carried out.

In this embodiment, as shown in FIG. 16, the biosensor 50, the electrochemical measurement circuit section 51, the data processing section 52, and the data notification section 53 are connected by the wiring 54. A configuration in which the electrochemical measurement circuit section 51 and the data notification section 53 are directly connected without providing the measurement circuit section 51 can also be employed. In this case, the analog signal obtained from the biosensor 50 is sent to the data notification unit 53 as it is, and the measured value is displayed by a display method using a scale and a needle. In this case, it is convenient to attach a table or the like for converting the displayed value into a urine sugar level or a blood sugar level.

(Seventh Embodiment) This embodiment is different from the embodiment shown in FIG.
6 shows an example of a measuring instrument further provided with a temperature sensor 56 and a pH sensor 57 in addition to the measuring instrument No. 6. Hereinafter, FIG.
This will be described with reference to FIG.

As shown in FIG. 18, the measuring device includes a biosensor 50, an electrochemical measurement circuit section 51, a data processing section 52, a data notification section 53, a temperature sensor 56,
The pH sensor 57 is connected with the wiring 54.

In the data processing section 52, the temperature sensor 56 and p
The electric signal from the H sensor 57 is processed, and the temperature and pH are processed.
Is calculated. Then, the measured values of the specific components in the measurement sample calculated in the data processing unit 52 are the temperature and the pH.
And is displayed on the data notification unit 53.

The temperature sensor 56 is not particularly limited as long as it can obtain data in a format that can be processed by the data processing section 52, but a thermocouple thermometer or a resistance thermometer is preferable. The temperature sensor 56 measures the temperature of the measurement sample or the temperature of the measurement environment. When measuring the temperature of the measurement sample, for example, the temperature sensor 56 is formed on a substrate provided with a biosensor including an enzyme electrode. In this way, the temperature of the measurement sample can be measured with high accuracy, and accurate correction can be performed when measuring a specific component in the measurement sample. Alternatively, a configuration may be adopted in which a temperature sensor independent of the biosensor is provided, and the biosensor and the temperature sensor 56 are simultaneously immersed in the measurement sample. With this configuration, it is not necessary to replace the temperature sensor at the same time as the replacement of the biosensor, and the cost can be reduced. When measuring the temperature of the measurement environment, a configuration is provided in which a temperature sensor independent of the biosensor is provided, and the temperature sensor 56 is installed in the measurement environment. The temperature sensor 56 is installed inside the data notification unit 53 and the electrochemical measurement circuit unit 51, for example. This makes it possible to easily check whether the measurement environment is within the measurable temperature condition.

FIG. 15 shows an example of a measuring instrument in which a temperature sensor 56 is formed on a substrate provided with a biosensor. This measuring instrument has a working electrode 7, a counter electrode 8, and a reference electrode 9 formed on an insulating substrate 1.
Is provided. On the working electrode 7, the counter electrode 8, and the temperature sensor 56, the binding layer 3, the immobilized enzyme layer 4, and the restricted permeation layer 5 are formed in this order, and on the reference electrode 9,
The bonding layer 3 and the protective layer 20 are formed. With such a configuration, it is possible to accurately correct the measured value based on the temperature.

As the pH sensor 57, a glass electrode or an ion-sensitive field effect transistor can be preferably used, but it is not limited to these. For calibration of the pH sensor 57, a solution in which a pH indicator is previously dissolved in a calibration liquid used when configuring the biosensor 50 can be used. By doing so, the biosensor 50
And the calibration of the pH sensor 57 can be performed simultaneously. The pH indicator is preferably an oxalate solution or a phthalate solution used in a usual glass pH meter.

By using the measuring instrument of the present embodiment, it becomes possible to accurately measure a specific component in a measurement sample having a wide temperature range and a wide pH range. The temperature of each measured sample,
This is because the measured value of the enzyme electrode can be corrected using the pH.

Although the temperature sensor 56 and the pH sensor 57 are connected to the data processing section 52 in this embodiment, they may be connected to the electrochemical measurement circuit section 51.

(Eighth Embodiment) This embodiment is different from the embodiment shown in FIG.
8, a communication processing unit connected to the data processing unit is further provided for the measuring device, and the communication processing unit
The data obtained by the data processing unit is transferred outside the measuring instrument. Hereinafter, description will be made with reference to FIG.

As shown in FIG. 19, the measuring instrument of this embodiment has a configuration in which a data processing section 52 and a communication processing section 58 are connected by a wiring 54. The communication processing unit 58 is a means for transmitting information on measured values to the outside. Usually, a modem is used, but it is not limited as long as it has a communication processing function. Communication lines used for transmission include, but are not limited to, telephone lines, infrared, wireless, and the like. Examples of the information transmitted include information processed by the data processing unit 52 and information displayed by the data notification unit 53. For example, the current value of the biosensor 50, password, measurement time, pH, temperature, memo content,
The measured value calculated by the data processing unit 52, the biosensor 5
0 replacement time, biosensor 50 calibration time, biosensor 50 operation check and malfunction check, abnormal current value,
The signal from the electrochemical measurement circuit unit 51 processed by the calculation unit of the data processing unit 52 is transmitted to the outside of the measuring instrument by the communication processing unit 58. The transmission destination is a server or a computer connected through a communication line or the like. The information to be transmitted can be appropriately selected by setting.

By using the measuring device of this embodiment, it becomes possible for a diabetic patient at home to measure his or her own urine sugar and transmit the measurement result to a medical institution such as a hospital through a telephone line. As a result, appropriate advice such as diet management and exercise management can be received from a medical institution, and the condition management of a diabetic patient at home becomes possible. Further, since data such as a malfunction of the biosensor can also be transmitted, it is possible to appropriately receive services such as repair and maintenance of the device from a manufacturer, for example.

(Ninth Embodiment) This embodiment is different from the ninth embodiment shown in FIG.
9 shows an example of a measuring instrument further including a printing unit 59 in the measuring instrument 9. Hereinafter, description will be made with reference to FIG.

As shown in FIG. 20, the measuring instrument of this embodiment has a configuration in which a data processing section 52 and a printing section 59 are connected by a wiring 54. The printing unit 59 may be a thermal type, a thermal transfer type, a dot impact type, an ink jet type, or a laser beam dry type, but is not particularly limited. Desirably, a low-cost, simple thermal structure is preferred. Printing unit 5
The wiring 54 connected to the printing unit 5 is not limited to an electric wire,
Infrared rays may be used in consideration of a usage pattern when 9 is not used. The printing unit 59 only needs to be able to print the data displayed on the data notification unit 53, but it is also possible to limit the data to be printed by setting.

The use of the measuring device of the present embodiment not only makes it possible to print and save data such as measured values on paper, but also allows a diabetic patient to print a measurement result using a printing function. The doctor can bring the completed paper to the hospital and show the result to the doctor, and receive appropriate advice from the doctor who has watched the measurement result.

(Embodiment 10) This embodiment shows an example of a measuring device provided with an external storage unit 55 in addition to the measuring device shown in FIG. Hereinafter, description will be made with reference to FIG.

As shown in FIG. 21, the measuring instrument of this embodiment has a configuration in which a data processing section 52 and an external storage section 55 are connected by a wiring 54. As the external storage unit 55, a normal storage medium can be used, and a magnetic storage medium such as a floppy disk, a semiconductor storage medium such as a memory card, and an optical storage medium such as an optical disk are preferably used. This is because it can be easily attached and detached and can be obtained at a low price.

By using the measuring instrument of the present embodiment, measured data can be stored in a storage medium, so that a user can bring this storage medium to a hospital as needed. Then, the doctor at the hospital can analyze the stored measurement data and take appropriate medical measures for the diabetic patient or the like. Further, a large amount of measurement data can be stored for a long period of time. Further, since the management is performed by the password, the privacy of the patient can be protected, and one apparatus can be used by a plurality of persons. The contents to be stored can be appropriately selected by setting.

[0155]

The present invention will be described in more detail with reference to the following examples.

Example 1 First, a working electrode (area of 7 mm ² ) made of platinum and a counter electrode (area of 4 mm ² ) and a reference electrode made of silver / silver chloride (area of 1 mm) were placed on a 10 mm × 6 mm quartz substrate.
mm ² ).

Subsequently, a 1 v / v% γ-aminopropyltriethoxysilane solution was spin-coated on the entire surface to form a binding layer. Thereafter, a 22.5 w / v% albumin solution containing glucose oxidase and 1 v / v% glutaraldehyde was spin-coated to form an immobilized enzyme layer.

After that, the following two types of enzyme electrodes were prepared by changing the structure of the outermost layer (restricted transmission layer). (1) The entire surface of the immobilized enzyme layer was spin-coated with a fluoroalcohol ester of methacrylic acid resin adjusted to 0.3% by weight using perfluorohexane, and then dried to form a restricted permeation layer. The first enzyme electrode was produced. Spin coating conditions were 3000 rpm for 30 seconds. As the fluoroalcohol ester of the methacrylic acid resin, Florad 722 manufactured by Sumitomo 3M Limited was used. Florard 722 is a polymethacrylic acid 1H, 1H
-Perfluorooctyl, having an average molecular weight (Mn) of about 7000 (GPC measurement). As a diluent, perfluorohexane, Florad 726 manufactured by Sumitomo 3M Limited was used. In the same manner, the film thickness of a sample obtained by directly spin-coating a fluoroalcohol ester of methacrylic acid resin on a quartz substrate was measured.
After the film was formed, a part of the film was peeled off with an ultrasonic cutter to form irregularities, and then the film thickness was measured by measuring the irregularities with an atomic force microscope. The thickness of the fluoroalcohol ester film of the methacrylic acid resin was about 50 nm.

(2) The entire surface of the immobilized enzyme layer was spin-coated with polyalkylsiloxane prepared at 10 w / v% using toluene, and then dried to form a restricted permeation layer. An enzyme electrode was prepared. The polyalkylsiloxane used was Pergan Z manufactured by Dow Corning.

The two types of sensors provided with either the first or second enzyme electrode manufactured as described above were
PH 7 TES containing 0 mM sodium chloride
It is immersed in Tris (hydroxymethyl) methyl 2-aminoethanesulfonic acid) buffer and stored, and a glucose standard solution of 200 mg / dl is given once a day.
It was measured for 20 days. FIG. 5 shows the sensor outputs of the two sensors with respect to glucose as relative output values when the output value on the first day is 100%. Table 1 shows data obtained by observing the surface of the restricted transmission layer with a scanning electron microscope after a certain period of use and comparing the frequency of occurrence of cracks.

The sensor using polyalkylsiloxane is 7
After a period of days, the sensor output began to increase (FIG. 5). In addition, cracks were formed in the film from the initial state, and the cracks tended to increase with time (Table 1). On the other hand, a sensor using a fluoroalcohol ester of methacrylic acid resin gives a stable sensor output for at least 20 days,
No cracks were observed.

[0162]

[Table 1]

The frequency of occurrence was determined by dividing the frequency of cracks observed in an area of 1 cm × 1 cm into five levels. 1 ... not detectable 2 ... slight occurrence (several places) 3 ... occurrence (several dozen places or one large crack) 4 ... many occurrences (several hundred places or several large cracks) 5 ... very many occurrences (large Based on the results in Table 1, it is considered that the cause of the increase in the output of the relative sensor is a crack in the restricted transmission layer. It is considered that the cracks in the restricted permeation layer occurred because the lower immobilized enzyme layer could not withstand swelling. The results of this example show that the restricted permeation layer composed of a fluoroalcohol ester of methacrylic acid resin can maintain a sufficient membrane strength to allow swelling even if an enzyme film is provided below.

In this embodiment, a sensor having a working electrode, a counter electrode, and a reference electrode is used, and a binding layer, an immobilized enzyme layer, and a restricted permeation layer are formed on all of these electrodes. May be formed only on the working electrode.

Example 2 First, a working electrode (area of 7 mm ² ) made of platinum and a counter electrode (area of 4 mm ² ) and a reference electrode made of silver / silver chloride (area of 1 mm) were placed on a 10 mm × 6 mm quartz substrate.
mm ² ).

Subsequently, a 1 v / v% γ-aminopropyltriethoxysilane solution was spin-coated on the entire surface to form a binding layer. Thereafter, a 22.5 w / v% albumin solution containing glucose oxidase and 1 v / v% glutaraldehyde was spin-coated to form an immobilized enzyme layer.

Thereafter, a fluoroalcohol ester of an acrylic acid resin adjusted to 0.3% by weight using xylene hexafluoride was applied on the immobilized enzyme layer by spin coating, followed by drying, followed by drying. Was formed. Thus, an enzyme electrode was produced. Spin coating conditions were 3000 rpm for 30 seconds. The coating solution was a xylene hexafluoride solution of polyacrylic acid 1H, 1H, 2H, 2H-perfluorodecyl (acrylic resin content 17%, xylene hexafluoride content 83%).
%, And a viscosity of 20 cps (25 ° C.) whose concentration was adjusted by further adding xylene hexafluoride as described above.

The sensor provided with the enzyme electrode prepared as described above was used for a pH 7 containing 150 mM sodium chloride.
TES (N-tris (hydroxymethyl) .methyl-2-aminoethanesulfonic acid) buffer solution and stored, and a 200 mg / dl glucose standard solution was measured once a day for 20 days. In addition, the surface of the restricted transmission layer was observed with a scanning electron microscope to confirm the state of crack generation. As a result, the sensor of this example gave a stable sensor output for at least 20 days, similarly to the sensor using the fluoroalcohol ester of the acrylic resin of Example 1, and the occurrence of cracks on the surface of the restricted transmission layer was also observed. Did not.

Example 3 First, a working electrode (area of 7 mm ² ) made of platinum and a counter electrode (area of 4 mm ² ) and a reference electrode made of silver / silver chloride (area of 1 mm) were placed on a 10 mm × 6 mm quartz substrate.
mm ² ).

Subsequently, a 1 v / v% γ-aminopropyltriethoxysilane solution was spin-coated on the entire surface to form a bonding layer, and then a 5 w / v% perfluorocarbon sulfonic acid resin solution was spin-coated to form a perfluorocarbon An ion exchange resin layer containing a sulfonic acid resin (Nafion) as a main component was formed. Next, 22.5 w / v% containing glucose oxidase and 0.5 v / v% glutaraldehyde
The albumin solution was spin-coated to form an immobilized enzyme layer.

Then, 0, 0.02, 0.06,
Methacrylic acid resin fluoroalcohol ester solutions having a concentration of 0.1 or 0.3% by weight were formed by spin coating. Spin coating conditions were 3000 rpm for 30 seconds.

As the fluoroalcohol ester of the methacrylic acid resin, Florad 722 manufactured by Sumitomo 3M Ltd. was used. The undiluted solution of Florad 722 is 2% by weight in terms of fluoroalcohol ester of methacrylic acid resin. As a diluent, perfluorohexane, Florad 726 manufactured by Sumitomo 3M Limited was used. The conditions for forming the fluoroalcohol ester of the methacrylic acid resin are concentrations appropriately diluted with Florade 726.

As shown in FIG. 6, the relative output value of each sensor indicates that the limited permeability of glucose was observed when the fluoroalcohol ester concentration of the methacrylic acid resin was 0.02% by weight or more. .1% by weight enables a wide range of measurements. Especially 0.3
In the case of the weight% or more, the current output value showed linearity up to a concentration of 3000 mg / dl, and a high-concentration glucose solution could be measured. The response time of the sensor at this time was about 15 seconds or less on average. Such a high response speed is obtained because the restricted transmission layer can be formed as a very thin uniform thin film. When spin coating is performed at 3000 rpm for 30 seconds as in the present embodiment, a uniform thin film of about 0.01 μm to 0.1 μm can be obtained.

Example 4 First, a working electrode (area of 7 mm ² ) made of platinum and a counter electrode (area of 4 mm ² ) and a reference electrode made of silver / silver chloride (area of 1 mm) were placed on a 10 mm × 6 mm quartz substrate.
mm ² ).

Subsequently, a 1 v / v% γ-aminopropyltriethoxysilane solution was spin-coated to form a bonding layer, and then a 5 w / v% perfluorocarbon sulfonic acid resin solution was spin-coated to form a perfluorocarbon sulfonic acid solution. An ion exchange resin layer containing resin (Nafion) as a main component was formed. Next, it contains glucose oxidase and contains 1 v /
A 22.5 w / v% albumin solution containing v% glutaraldehyde was spin-coated to form an immobilized enzyme layer.

Thereafter, two types of enzyme electrodes were produced by changing the structure of the outermost layer.

For one, a fluoroalcohol ester of methacrylic acid resin adjusted to 0.3% by weight with perfluorohexane was spin-coated. Spin coating conditions were 3000 rpm for 30 seconds. As the fluoroalcohol ester of the methacrylic acid resin, Florad 722 manufactured by Sumitomo 3M Limited was used. The average molecular weight (Mn) is about 7000. Perfluorohexane, a diluent, was manufactured by Sumitomo 3M Co., Ltd.
26 was used.

On the other hand, a polyalkylsiloxane prepared at 10 w / v% using toluene was spin-coated on the immobilized enzyme layer. The polyalkylsiloxane used was Pergan Z manufactured by Dow Corning.

The two kinds of sensors provided with the enzyme electrodes prepared as described above were subjected to a pH 7 buffer containing 150 mM sodium chloride (N-tris (hydroxymethyl) methyl 2-aminoethanesulfonic acid). The sample was immersed in the solution and stored, and a 200 mg / dl glucose standard solution containing 400 mg / dl urea was continuously measured 10 times. FIG. 7 shows the sensor output for glucose of the two types of sensors as a relative output value when the initial output value is 100%.

As a result, the sensor output of the polyalkylsiloxane sensor began to decrease after the second measurement, and the sensor output decreased to 86% at the tenth measurement. On the other hand, a sensor using a fluoroalcohol ester of a methacrylic acid resin showed a stable output in ten repeated measurements. The reason why the output of the sensor using fluoro alcohol ester of methacrylic acid resin was stable is that
This is probably because urea is unlikely to adhere because the surface free energy of the fluoroalcohol ester of the methacrylic acid resin is lower than that of the polyalkylsiloxane.

Example 5 First, a working electrode (area of 7 mm ² ) made of platinum and a counter electrode (area of 4 mm ² ) and a reference electrode made of silver / silver chloride (area of 1 mm) were placed on a 10 mm × 6 mm quartz substrate.
mm ² ).

Subsequently, a 1 v / v% γ-aminopropyltriethoxysilane solution was spin-coated to form a bonding layer, and then a 5 w / v% perfluorocarbon sulfonic acid resin solution was spin-coated to form a perfluorocarbon sulfonic acid solution. An ion exchange resin layer containing resin (Nafion) as a main component was formed. Next, it contains glucose oxidase and contains 1 v /
A 22.5 w / v% albumin solution containing v% glutaraldehyde was spin-coated to form an immobilized enzyme layer.

Thereafter, two kinds of enzyme electrodes were produced by changing the structure of the outermost layer.

For one, a fluoroalcohol ester of methacrylic acid resin adjusted to 0.3% by weight using perfluorohexane was spin-coated. Spin coating conditions were 3000 rpm for 30 seconds. As the fluoroalcohol ester of the methacrylic acid resin, Florad 722 manufactured by Sumitomo 3M Limited was used. The average molecular weight (Mn) is about 7000. Perfluorohexane, a diluent, was manufactured by Sumitomo 3M Co., Ltd.
26 was used.

On the other hand, a polyalkylsiloxane prepared at 10 w / v% with toluene was spin-coated on the immobilized enzyme layer. The polyalkylsiloxane used was Pergan Z manufactured by Dow Corning.

The two types of sensors provided with the enzyme electrodes prepared as described above were subjected to a pH 7 TES (N-tris (hydroxymethyl) -methyl-2-aminoethanesulfonic acid) buffer containing 150 mM sodium chloride. The sample was immersed in the solution and stored, and a normal urine control (Lifocheck) manufactured by Bio-Rad Inc. containing about 20 mg / dl of glucose was measured 10 times in succession. FIG. 8 shows the sensor outputs for glucose of the two types of sensors as relative output values when the initial output value is 100%.

As a result, the sensor output of the polyalkylsiloxane sensor began to decrease after the second measurement, and the sensor output decreased to 28% at the tenth measurement. On the other hand, a sensor using a fluoroalcohol ester of a methacrylic acid resin showed a stable output in ten repeated measurements. This indicates that the fluoroalcohol ester of methacrylic acid resin can practically sufficiently prevent the attachment of a substance that causes a decrease in sensor output contained in urine.

The reason why the output of the sensor using the fluoroalcohol ester of methacrylic acid resin was stable is that the surface tension of the sensor is lower than that of the polyalkylsiloxane, so that the sensor reacts with urea and other interfering substances which cause a decrease in the sensor output. It seems to be not.

Example 6 One counter electrode was placed on a quartz substrate.
One reference electrode and three working electrodes (electrode area 3 mm ² )
Was formed. Subsequently, a 1 v / v% γ-aminopropyltriethoxysilane solution was spin-coated on the entire surface. Next, using photolithography technology, a 22.5 w / v% albumin solution containing glucose oxidase and 1 v / v% glutaraldehyde on each of the three working electrodes, lactate oxidase and 0.5 v / v% glutar 22.5w / v% containing aldehyde
Albumin solution and ethanol oxidase and 1 v /
A 22.5 w / v% albumin solution containing v% glutaraldehyde was spin coated.

After the immobilized enzyme layer was formed in this manner, two types of enzyme electrodes were produced by changing the structure of the outermost layer.

For one, a fluoroalcohol ester of methacrylic acid resin adjusted to 0.3% by weight using perfluorohexane was spin-coated. Spin coating conditions were 3000 rpm for 30 seconds. As the fluoroalcohol ester of the methacrylic acid resin, Florad 722 manufactured by Sumitomo 3M Limited was used. The average molecular weight (Mn) is about 7000. Perfluorohexane, a diluent, was manufactured by Sumitomo 3M Co., Ltd.
26 was used.

As for the other, 5 μm was placed on the immobilized enzyme layer.
A w / v% perfluorocarbon sulfonic acid resin solution was spin-coated to form an ion-exchange resin layer containing a perfluorocarbon sulfonic acid resin (Nafion) as a main component.

Using the sensor provided with the enzyme electrode prepared as described above, the fluctuation of the measured value at the time of repeated measurement was evaluated. A mixed solution containing 100 mg / dl glucose, 20 mM lactic acid and 20 mM ethanol was repeatedly measured 11 times, and the coefficient of variation (CV value) of the measured value was determined. The coefficient of variation indicates a value represented by standard deviation / mean value × 100.

In the case where an enzyme electrode having a methacrylic acid resin fluoroalcohol ester layer as the outermost layer was used, as shown in Table 2, stable measurement values were obtained regardless of the measurement components. The reason for this is that the resin layer has no charge and therefore has a small interaction with an electrolytic substance such as lactic acid, the resin layer has excellent chemical resistance to a measurement substance such as ethanol, and is formed on the same insulating substrate. Two or more working electrodes and two or more enzymes do not affect each other's component measurement.

On the other hand, when the perfluorocarbon sulfonic acid resin layer is formed as the outermost layer, this resin film dissolves in ethanol, so that the limiting permeability decreases when measuring ethanol. In addition, since this resin film has a charge, the fluctuation becomes large when an electrolytic substance such as lactic acid is measured.

[0196]

[Table 2]

Example 7 First, a working electrode (area of 7 mm ² ) made of platinum and a counter electrode (area of 4 mm ² ) and a reference electrode made of silver / silver chloride (area of 1 mm) were placed on a 10 mm × 6 mm quartz substrate.
mm ² ).

Subsequently, a 1 v / v% γ-aminopropyltriethoxysilane solution was spin-coated on the entire surface to form a binding layer. Thereafter, a 22.5 w / v% albumin solution containing glucose oxidase and 1 v / v% glutaraldehyde was spin-coated to form an immobilized enzyme layer. Thereafter, the following two types of enzyme electrodes were produced by changing the configuration of the outermost layer.

(1) The first enzyme electrode was prepared by spin-coating the entire surface of the immobilized enzyme layer with a fluoroalcohol ester of methacrylic acid resin adjusted to 0.3% by weight using perfluorohexane. did. Spin coating conditions were 3000 rpm for 30 seconds. As the fluoroalcohol ester of the methacrylic acid resin, Florad 722 manufactured by Sumitomo 3M Limited was used. Florard 722,
It is polymethacrylic acid 1H, 1H-perfluorooctyl, and has an average molecular weight (Mn) of about 7000. As a diluent, perfluorohexane, Florad 726 manufactured by Sumitomo 3M Limited was used.

(2) A xylene hexafluoride solution containing 1.7% by weight of a copolymer of 1H, 1H, 2H, 2H-perfluorodecyl acrylate and cyclohexyl methacrylate was entirely coated on the immobilized enzyme layer. This was prepared and the solution was spin-coated to produce a second enzyme electrode. The copolymerization ratio of 1H, 1H, 2H, 2H-perfluorodecyl acrylate to cyclohexyl methacrylate is about 8: 2, the number a of 1H, 1H, 2H, 2H-perfluorodecyl acrylate and the number of methacrylic acid The ratio a / b of the number b of the cyclohexyl groups was about 8/2.

The two types of sensors provided with either the first or second enzyme electrode manufactured as described above were
PH 7 TES containing 0 mM sodium chloride
It was immersed and stored in a Tris (hydroxymethyl) methyl 2-aminoethanesulfonic acid) buffer at 40 ° C, and a glucose standard solution of 0 to 2000 mg / dl was measured after 48 hours. The applied potential was 700 mV at the working electrode with respect to the reference electrode.

As described above, the stability of the sensor output at 40 ° C. was evaluated. FIG. 12 shows the measurement results of the sensor output before immersion and 48 hours after immersion. FIG. 12 (a)
Is a measurement result using a sensor provided with the first enzyme electrode. FIG. 12 (b) shows a measurement result using a sensor provided with the second enzyme electrode. In the sensor equipped with the first enzyme electrode, sufficient stability was not always obtained, whereas in the sensor equipped with the second enzyme electrode, the sensor before immersion (0 hour in the figure) and after 48 hours had elapsed. It was found that the outputs were almost the same and showed excellent stability.

Example 8 First, a working electrode (area of 7 mm ² ) made of platinum and a counter electrode (area of 4 mm ² ) and a reference electrode made of silver / silver chloride (area of 1 mm) were placed on a 10 mm × 6 mm quartz substrate.
mm ² ).

Subsequently, a 1 v / v% γ-aminopropyltriethoxysilane solution was spin-coated on the entire surface to form a binding layer. Thereafter, a 22.5 w / v% albumin solution containing glucose oxidase and 1 v / v% glutaraldehyde was spin-coated to form an immobilized enzyme layer.

Thereafter, polyacrylic acid 1H, 1H, 2
A xylene hexafluoride solution in which 0.85% by weight of H, 2H-perfluorodecyl and 0.085% by weight of cyclohexyl polymethacrylate are prepared,
This solution was spin-coated to produce a second enzyme electrode.

With respect to the sensor provided with the enzyme electrode prepared as described above, a calibration curve was prepared for a glucose standard solution of 0 to 2000 mg / dl. The applied potential was 700 mV at the working electrode with respect to the reference electrode. The obtained calibration curves are shown in FIGS. 13 (a) and (b). Note that these calibration curves are obtained for the same sensor. As can be seen, the sensor of this example shows good sensitivity over a wide range from 0 to 2000 mg / dl. In particular, 2-50m
It shows a sufficient current value even for glucose of g / dlmg / dl. For this reason, if the sensor of this embodiment is used, it is possible to measure urine sugar of a person whose urinary sugar level is within a normal range or a person who falls under the reserve army of diabetes, and it is possible to collect data useful for prevention of diabetes. Becomes

Next, the urine of a healthy person containing about 2 mg / dl of glucose was measured ten times in succession. FIG. 14 shows the results. The reproducibility was about 3%, and low-concentration glucose contained in urine could be measured with good reproducibility.

(Embodiment 9) This embodiment shows an example of a measuring instrument having the configuration shown in FIG.

First, a procedure for manufacturing the biosensor portion of the measuring instrument according to the present embodiment will be described. First 10mm x 6
Working electrode made of platinum (area 7 m)
m ² ), a counter electrode (area 4 mm ² ), and a reference electrode (area 1 mm ² ) composed of silver / silver chloride. Next, 1v / v on the whole surface
% Γ-aminopropyltriethoxysilane solution was spin coated to form a tie layer. After that, 56.5U /
An immobilized enzyme layer was formed by spin-coating a 22.5 w / v% albumin solution containing μl glucose oxidase and 1 v / v% glutaraldehyde. Then, a 1.7% by weight polyfluoro alcohol ester solution of an acrylic acid resin was spin-coated thereon to form a restricted permeation layer. As the polyfluoroalcohol ester of the acrylic acid resin, polyacrylic acid 1H, 1H, 2H, 2H-perfluorodecyl was used. The diluent used was xylene hexafluoride. Spin coating condition is 3000rpm
m and 30 seconds.

Using the biosensor having the electrode portions formed as described above, a measuring instrument having the structure shown in FIG. 16 was manufactured.
The electrode portion and the flexible substrate were connected by wire bonding, and the flexible substrate and the electrochemical measurement circuit portion were connected using a pin jack type electric wire.

The electrochemical measurement circuit is a potentiostat HOKUTODENKOPOTENTIOSTAT / GALVANOSTATH manufactured by Hokuto Denko.
A150G was used. As a data processing device, a personal computer PC-9821RaII23 manufactured by NEC Corporation was used. As the data notification unit 53, a display PC-KP531 manufactured by NEC Corporation was used. The electrochemical measurement circuit, the data processing device, and the data notification unit 53 were connected by a pin jack type electric wire.

Next, the operation of the measuring instrument of this embodiment will be described. The user immerses the biosensor equipped with the enzyme electrode in 1 mM TES (N-tris (hydroxyl) -methyl-2-aminoethanesulfonic acid) buffer at pH 7 containing 150 mM sodium chloride, and then immerses the device in the device. Turned on. Then, [Time is set in the data notification section. Please enter the current time. ] Was displayed. When the user operates the keys based on this display and inputs the current time, the data notification section displays the message "The current time has been input. ] Was displayed. If the time is not entered correctly, select [Set time again. Please enter the current time. ] Is displayed. Thus, the input current time is stored in the data processing unit.

[0213] Next, the data notification section displays [Preparing. Please wait for a little while. ] Was displayed. When the current value sent from the enzyme electrode stabilizes, the data notification section displays [Calibrate. Immerse the electrode in the calibration solution. ] Was displayed. Based on this display, the user can
Calibration was performed by immersion in a calibration solution of 200 mg / dl glucose.
Then, the data notification section displays [Calibration completed successfully.
After washing, return to buffer. ] Was displayed. The data processing unit determines whether or not calibration has been performed normally, and the result is displayed on the data notification unit. If the calibration was not performed successfully, the message [Calibration cannot be performed. Wash the electrode and immerse it in the calibration solution again. ] Or [The electrode is broken. Please replace. Is displayed. After the calibration was completed, the user dipped the enzyme electrode in the buffer to prepare for the measurement. If the electrode is not returned to the buffer for more than 10 seconds after the calibration is completed, a warning sound is generated.

Subsequently, the user selected the item "start measurement" displayed on the data notification section. Then, the data notification section displays [Start measurement. Immerse the electrode in urine. ] Was displayed. Based on this display, the user dipped the electrode in urine and started measurement. After 10 seconds from the start of measurement, the data notification section displays [Measurement completed successfully. The urine sugar level is XXmg / dl. ] Was displayed. The data processing unit determines whether or not the measurement has been performed normally, and the result is displayed on the data notification unit. If the calibration was not performed properly, [Measurement is not possible. Wash the electrode and immerse it again in urine. ] Or [The electrode is broken. Please replace. ] Is displayed on the data notification unit.

[0215] After the measurement is completed, the data notification section displays [Wash electrode and return to buffer. ] Was displayed. If the electrode is not returned to the buffer for more than 10 seconds after the end of the measurement, a warning sound is generated. After that, the user selected the item of “measurement end” in the data notification unit to end the measurement.

In the measuring instrument of this embodiment, the time to be measured can be set in advance. At the set time,
When the notification sound is generated, the data notification section displays [Start measurement. Immerse the electrode in urine. Is displayed. The set time can be set arbitrarily, and a plurality of times can be set.

In inputting to the data processing unit in the measuring instrument of this embodiment, a notification sound is emitted when the input is accepted and when the input is not accepted. The notification light may be emitted instead of the notification sound. If an abnormal current occurs between the enzyme electrode, the electrochemical measurement circuit, the data processing device, and the wires, the abnormal current notification means [An abnormal current was detected. ] Is displayed on the data notification unit. This display can prevent the device from being damaged.

Further, since the biosensor, the electrochemical measurement circuit, and the data processing device are all connected by pin-jack type electric wires, they can be easily attached and detached between them, and can be replaced as necessary. is there.

As described above, by using the measuring instrument of the present embodiment, measurement can be performed at a regular time, and furthermore, anyone can easily handle the apparatus without causing any operation error.

(Embodiment 10) This embodiment shows an example of a measuring instrument having the configuration shown in FIG. This measuring device is obtained by adding a pH sensor and a temperature sensor to the measuring device of the ninth embodiment.

As a temperature sensor and a pH sensor, a thermocouple type temperature sensor and an ion-sensitive field effect transistor type pH sensor were used, respectively. pH sensor, temperature sensor, electrochemical measurement circuit, data processing device,
And the data notification unit were connected by electric wires.

Hereinafter, the operation of the measuring instrument of this embodiment will be described. The user first immersed the enzyme electrode in a 1 mM TES (N-tris (hydroxyl) -methyl-2-aminoethanesulfonic acid) buffer solution containing 150 mM sodium chloride at pH 7, and then turned on the apparatus. About 1
After a minute, the base current value of the enzyme electrode stabilized. In this state, the enzyme electrode was immersed in a 200 mg / dl glucose standard solution to calibrate the enzyme electrode. Since the glucose standard solution also contains a pH indicator, calibration of the pH sensor can be performed at the same time. The power of the apparatus is not turned off while the enzyme electrode is connected except when the electrode is replaced.

Subsequently, the user selected the [start measurement] item displayed on the data notification section. Then, [Start measurement. Immerse the electrode in urine. ] Was displayed on the data notification unit.

[0224] Based on the display, the user continuously measured urine glucose of two diabetic patients as subjects each time.
In addition, the blood pressure and the body temperature of the subject were simultaneously input using the memo registration means at the time of measurement. As a result, 10 seconds after the first patient immersed the enzyme electrode in the urine, the data notification section displayed [The measurement was completed successfully. The urine sugar level is 80mg / dl. Is displayed, and at the same time, the message [Measurement is completed successfully. The urine sugar level is 80mg / dl. ] Was displayed. Then, about 20 seconds later, the second patient immersed the enzyme electrode in urine, and 10 seconds later, the data notification section displayed [The measurement was completed successfully. The urine sugar level is 180mg / dl. Is displayed, and at the same time, the message [Measurement is completed successfully. The urine sugar level is 180mg / dl. ] Was displayed. At this time, the existing clinical test equipment (Hitachi automatic analyzer 7050, glucose dehydrogenase method)
As a result of comparing the measured values with, the measured values almost match,
It showed high correlation.

As described above, by using the measuring instrument of this embodiment, it was possible to continuously measure urine sugar of two persons. In addition, it was possible for even a person with poor visual acuity to know his / her urine sugar level reliably. Furthermore, the body temperature and blood pressure that have been input using the memo registration means can be called and compared with the urinary sugar level, thereby enabling detailed disease state management. Also,
Since temperature and pH corrections were performed on the obtained measured values, it was possible to perform a measurement with high measurement accuracy comparable to that of an existing clinical test device.

(Embodiment 11) This embodiment shows an example of a measuring instrument having the configuration shown in FIG. This measuring device is obtained by adding a communication processing unit 58 to the measuring device of the tenth embodiment. The communication processing unit 58
NEC Corporation Modem Terminal Adapter PC-IT6
5S1P was used. The pH sensor, the temperature sensor, the electrochemical measurement circuit, the data processing device, the data notification unit, and the communication processing unit were all connected by electric wires.

Using this device, urine sugar of one diabetic patient was twice daily for 30 days (after breakfast and after dinner, respectively).
After the time), the measurement was continuously performed, and the data after the measurement was transmitted to the hospital one by one using a telephone line.

As a result, the patient adhered to the measurement time of urine sugar, and the hospital was able to graph and analyze the urine sugar value sent and manage the patient's condition appropriately.

(Embodiment 12) This embodiment shows an example of a measuring instrument having the configuration shown in FIG. This measuring device is different from the measuring device of Example 11 in that a printing unit 59 is further provided.
Has been added. As the printing unit 59, a laser printer Multiwriter2000X manufactured by NEC Corporation was used. Data processing unit and printing unit are printer cables
Connected with PC-CA202. Hereinafter, a result of measurement using the measuring device of the present embodiment will be described.

Using this device, urine glucose of 100 diabetic patients was continuously measured. Calibration was performed only once when the instrument was started. The same sample was also measured using an existing clinical test device, and the measurement results of the measuring device of this example and the existing clinical test device (Hitachi Automatic Analyzer 7050, glucose dehydrogenase method) were compared. As a result, the correlation coefficient was 0.96, and the regression equation was Y = 1.09X + 8.
It was 8. It has been clarified that the measuring device of the present embodiment can obtain the same measurement accuracy as that of the clinical test device. In addition, the measurement time when the measuring instrument of the present example was used was about 90 seconds per sample, and quick measurement was possible. Further, since the measuring instrument of the present example was provided with the printing section 59, the measurement result was printed quickly and could be confirmed. Patients could also bring a printed version of the measurements to the hospital for advice from a physician.

(Embodiment 13) This embodiment shows an example of a measuring instrument having the configuration shown in FIG. This measuring instrument is obtained by adding an external storage unit 55 to the measuring instrument of Example 12. As an external storage unit,
3.5 inch optical disk unit PC manufactured by NEC Corporation
-OD302R was used. The external storage device and the data processing unit were connected by an electric wire. Hereinafter, the operation of the measuring instrument of the present embodiment will be described.

The user first dipped the enzyme electrode in a 1 mM TES (N-tris (hydroxyl) -methyl-2-aminoethanesulfonic acid) buffer solution containing 150 mM sodium chloride at pH 7, and then turned on the power supply of the apparatus. I put it.
After about one minute, the base current value of the enzyme electrode was stabilized. In this state, immerse the enzyme electrode in 200 mg / dl glucose standard solution,
Calibration of the enzyme electrode was performed.

Next, the user selects the item of "input of the number of persons to be measured" displayed on the data notification unit, and inputs the number of persons to be measured. ] Was displayed. When the user inputs the number of people to be measured based on this display, the data notification section will perform [Measurement of ○ people. (Yes, Y / No, N)]. If [Yes, Y] is selected, [Measurement of ○○ is possible. ] Was displayed. If [No, N], click [Enter the number of people to be measured again]. ] Is displayed,
The above procedure is repeated until [Yes, Y] is selected.

Next, the user selected the item of [PIN] displayed on the data notification section, and then selected [Registration of PIN]. The data processing unit recognizes that the password input button has been pressed, and then registers the password in the data notification unit. Please enter a 4-digit number. ] Is displayed. When the user operates the keys based on this display and inputs a four-digit number, the data notification section displays "Please enter the same password. ] Was displayed. When the user enters the same number again, [Password accepted. ] Was displayed. The registration of the personal identification number is registered for the measurement person. Thus, the registered personal identification number is stored in the memory in the data processing unit.

[0235] Next, the data notification section displays [Start measurement. Enter your PIN and immerse the electrode in urine. ] Was displayed. Based on this display, the user entered the password and then dipped the electrode in urine to start the measurement. Then, the data notification section displays [Measurement completed successfully. The urine sugar level is XXmg / dl. ] Was displayed. If the measurement is not performed normally, [Cannot measure.
Wash the electrode and immerse it again in urine. ] Or [The electrode is broken. Please replace. ] Is displayed. If the correct password is not entered, [Start measurement again. Enter your PIN and immerse the electrode in urine. ] Is displayed. If the passwords do not match three times in a row, all the measurement data up to the previous time are erased and the setting returns to the initial setting.

[0236] After the measurement is completed normally, the data notification section displays [Wash the electrode and return to the buffer. ] Was displayed.

Next, the user clicks [Memo Registration] in the data notification section.
And select [Register memo? (Yes, Y / No, N)]. When [Y] was selected, the message [Enter your PIN] was displayed. After entering the PIN and entering the memo content, [Register memo? (Yes, Y / No, N)]. Enter [Y], enter a memo, and then select [Register memo again. (Yes, Y / No, N)]. The user entered [Y] and registered the memo. To stop these inputs, enter [N].
Also, when recalling, modifying, or deleting the registered memo, select [Enter the PIN and then specify the memo number. ] Is displayed. When the user inputs the personal identification number based on this display, the user can recall, modify, or delete the memo. If the security code is not entered correctly, [The security code does not match. Please enter your PIN again. ] Is displayed. If the passwords do not match three consecutive times, all the memo contents up to the previous time are erased and the settings are returned to the initial settings.

Next, the result of measurement using the measuring instrument of this embodiment will be described. Urine glucose of two diabetic patients was repeatedly measured twice a day for one week using the measuring instrument of this example. Calibration was performed only once when the instrument was started. The same sample was also measured using an existing clinical test device (Hitachi Automatic Analyzer 7050, glucose dehydrogenase method), and the measurement results of the measurement device of this example and the existing clinical test device were compared. As a result, the correlation coefficient was 0.955 (n = 28). It has been clarified that the measuring device of the present embodiment can obtain the same measurement accuracy as that of the clinical test device. In addition, since the patient name was input using the memo function, the data of the measured value was not confused, and furthermore, since the data was managed by the password, the privacy at the time of the measurement could be protected. In addition, the measured data could be displayed in a bar graph. Further, since the optical disk storing the data is portable, it was possible to manage the data with another personal computer and to analyze the data.

[0239]

As described above, the enzyme electrode of the present invention and the biosensor using the same are mainly composed of a polymer in which a pendant group containing a fluoroalkylene block is bonded to a fluorine-free vinyl polymer. The following effects are exhibited by having the limited transmission layer.

The first effect is that adhesion of contaminants such as proteins and urea compounds is suppressed, and stable output characteristics can be obtained even after long-term use. This is because a pendant group containing a fluoroalkylene block such as a fluoroalcohol ester group is hardly soluble in most non-fluorinated solvents and detergents such as surfactants. Therefore, a stable repeated measurement result can be obtained even in a component system containing various chemical substances such as a body fluid.

The second effect is that good adhesion to other organic polymer layers such as the immobilized enzyme layer can be obtained, the response speed can be increased, and the time required for washing can be shortened. The durability of the structure is improved, and an enzyme electrode which is less likely to be damaged even when used for a long time is obtained. The reason why good adhesion is obtained is that the polymer has a main chain composed of a vinyl polymer containing no fluorine. In addition, by adopting a structure in which the pendant group is bonded to the main chain via the ester group, the adhesion is further improved.

The third effect is that good limited permeability can be obtained, and the measurement density range can be greatly expanded. The reason why good restricted permeability can be obtained is that the polymer constituting the restricted permeation layer is a fluorine-free vinyl polymer,
It has a unique structure in which a pendant group containing at least a fluoroalkylene block is bonded.

The fourth effect is that since the restricted permeability is good, the thickness of the restricted transmission layer can be reduced, and the response speed and the time required for cleaning can be shortened. .

The fifth effect is that stable measurement can be performed even for ionized substances such as lactic acid. this is,
This is because the interaction with the ionized substance such as lactic acid is small because the limited permeation layer has no charge.

According to the present invention, an enzyme electrode and a biosensor excellent in mass productivity can be obtained. Since the enzyme electrode of the present invention can form its layer structure by applying various solutions by a spin coating method or the like, it is possible to divert most of the existing planar manufacturing process, and to use a large amount and low This is because production can be performed at a cost.

By incorporating the counter electrode and the reference electrode together with the working electrode on the insulating substrate, the size of the sensor itself can be reduced. Thereby, a sensor excellent in portability and the like can be obtained.

Furthermore, if the enzyme electrode of the present invention is provided with an immobilized enzyme layer on which a plurality of enzymes having different catalytic functions are immobilized, there is an advantage that a plurality of specific sample components in a measurement sample can be measured simultaneously. Can be

Further, if the biosensor of the present invention is used as a urine glucose sensor for measuring glucose (urine glucose) in urine, it is impossible for a human having a urine glucose value within a normal range, which was impossible with a conventional sensor. In addition, it is possible to measure urinary glucose of a person who falls under the reserve army of diabetes, and to collect data useful for preventing diabetes. In addition, by appropriately designing the layer configuration, it is possible to effectively eliminate the influence of urea, vitamin C, and acetaminophen contained in a large amount in urine on measured values.

Further, since the measuring instrument of the present invention has a biosensor having a working electrode of a specific structure, it has excellent long-term stability and can be used under a wide range of measuring conditions. In addition, the operation method is simple, and even a person unfamiliar with the device can easily handle it.

Further, in the method for producing an enzyme electrode of the present invention, a liquid containing a polymer component having a specific structure is applied and dried to form a restricted permeation layer. A restricted transmission layer having excellent adhesion, durability, and restricted permeability can be formed with good film thickness controllability.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of an enzyme electrode of the present invention.

FIG. 2 is a sectional view showing an example of the enzyme electrode of the present invention.

FIG. 3 is a sectional view showing an example of the enzyme electrode of the present invention.

FIG. 4 is a sectional view showing an example of the enzyme electrode of the present invention.

FIG. 5 is a diagram showing the stability of a glucose sensor (urine sugar sensor) of the present invention.

FIG. 6 is a diagram showing a relationship between a sensor output and a concentration of a fluoroalcohol ester of a methacrylic acid resin in the sensor of the present invention.

FIG. 7 is a diagram showing the stability of the glucose sensor (urine sugar sensor) of the present invention.

FIG. 8 is a diagram showing the stability of the glucose sensor (urine sugar sensor) of the present invention.

FIG. 9 is a cross-sectional view of a conventional enzyme electrode.

FIG. 10 is a schematic diagram of a biosensor of the present invention.

FIG. 11 is a sectional view of a conventional enzyme electrode.

FIG. 12 is a diagram showing the results of evaluating the sensor output stability at 40 ° C. of the glucose sensor (urine sugar sensor) according to the present invention.

FIG. 13 is a diagram showing measurement sensitivity of a glucose sensor (urine sugar sensor) according to the present invention.

FIG. 14 is a diagram showing the stability of a glucose sensor (urine sugar sensor) according to the present invention.

FIG. 15 is a diagram showing an example of a sensor part of the measuring instrument of the present invention.

FIG. 16 is a diagram showing an example of the configuration of a measuring instrument of the present invention.

FIG. 17 is a diagram showing an example of a configuration of a data processing unit included in the measuring device of the present invention.

FIG. 18 is a diagram illustrating an example of a configuration of a measuring instrument according to the present invention.

FIG. 19 is a diagram showing an example of the configuration of a measuring instrument of the present invention.

FIG. 20 is a diagram showing an example of the configuration of a measuring instrument of the present invention.

FIG. 21 is a diagram illustrating an example of a configuration of a measuring instrument according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Insulating substrate 2 Electrode 3 Binding layer 4 Immobilized enzyme layer 5 Restriction permeation layer 6 Ion exchange resin layer 7 Working electrode 8 Counter electrode 9 Reference electrode 10 Immobilized enzyme layer 20 Protective layer 30 Substrate 31 Electrode 32 Immobilized enzyme layer 33 Adhesive layer 34 Polymer layer 35 Restricted transmission layer 36 Adhesive layer 37 Protective layer 50 Biosensor 51 Electrochemical measurement circuit section 52 Data processing section 53 Data notification section 54 Wiring 55 External storage section 56 Temperature sensor 57 pH sensor 58 Communication processing section 60 Clocking means 61 time setting means 62 time notification means 63 operation explanation means 64 measured value storage means 65 password registration means 66 memo registration means 67 operation notification means 68 calibration time notification means 69 electrode replacement time notification means 70 abnormal current value notification means 71 electrode calibration means

Claims (55)

[Claims] An electrode provided on an insulating substrate, an immobilized enzyme layer formed on the electrode, and a restricted permeation layer formed on the immobilized enzyme layer. The enzyme electrode, wherein the permeable layer is mainly composed of a polymer in which a pendant group containing at least a fluoroalkylene block is bonded to a fluorine-free vinyl polymer. 2. The method according to claim 1, wherein the vinyl polymer is a homopolymer or a copolymer of one or more monomers selected from the group consisting of unsaturated hydrocarbons, unsaturated carboxylic acids, and unsaturated alcohols. The enzyme electrode according to claim 1, wherein 3. The enzyme electrode according to claim 1, wherein the vinyl polymer is a polycarboxylic acid. 4. The enzyme electrode according to claim 1, wherein the fluoroalkylene block is bonded to the vinyl polymer via an ester group. 5. The fluorine-containing pendant group represented by x / (x + y), where x is the number of fluorine atoms contained in the pendant group and y is the number of hydrogen atoms contained in the pendant group. The enzyme electrode according to any one of claims 1 to 4, wherein the ratio is 0.3 to 1. 6. The enzyme electrode according to claim 1, wherein the pendant group has 3 to 15 carbon atoms. 7. The polymer having a molecular weight of 1,000 to 5,
The enzyme electrode according to any one of claims 1 to 6, wherein the enzyme electrode is 0000. 8. An electrode provided on an insulating substrate, an immobilized enzyme layer formed on the electrode, and a restricted permeation layer formed on the immobilized enzyme layer. An enzyme electrode, wherein the permeable layer is mainly composed of a fluoroalcohol ester of polycarboxylic acid (A). 9. An electrode provided on an insulating substrate, an immobilized enzyme layer formed on the electrode, and a restricted permeation layer formed on the immobilized enzyme layer. An enzyme electrode, wherein the permeable layer comprises a fluoroalcohol ester of polycarboxylic acid (A) and an alkyl alcohol ester of polycarboxylic acid (B). 10. The enzyme electrode according to claim 9, wherein the polycarboxylic acid (B) is polymethacrylic acid, polyacrylic acid, or a copolymer of acrylic acid and methacrylic acid. 11. The alkyl alcohol ester of the polycarboxylic acid (B) is an ester compound in which at least a part of a carboxyl group of the polycarboxylic acid (B) is esterified with an alkyl alcohol having 2 to 10 carbon atoms. The enzyme electrode according to claim 9 or 10, wherein the enzyme electrode is provided. 12. The enzyme electrode according to claim 11, wherein the alkyl alcohol ester of the polycarboxylic acid (B) is polyhexyl methacrylate. 13. The enzyme according to claim 8, wherein the polycarboxylic acid (A) is polymethacrylic acid, polyacrylic acid, or a copolymer of acrylic acid and methacrylic acid. electrode. 14. When the number of fluorine atoms in the fluoroalcohol ester group contained in the fluoroalcohol ester of the polycarboxylic acid (A) is x and the number of hydrogen atoms is y, it is represented by x / (x + y). The enzyme electrode according to any one of claims 8 to 13, wherein the fluoroalcohol ester group has a fluorine content of 0.3 to 1. 15. The fluoroalcohol ester group contained in the fluoroalcohol ester of the polycarboxylic acid (A) has a fluoroalcohol ester group having 3 to 1 carbon atoms.
The enzyme electrode according to any one of claims 8 to 14, wherein the enzyme electrode is 5. 16. The enzyme according to claim 8, wherein the fluoroalcohol constituting the fluoroalcohol ester group contained in the fluoroalcohol ester of the polycarboxylic acid (A) is a primary alcohol. electrode. 17. The fluoroalcohol ester of the polycarboxylic acid (A) is polymethacrylic acid 1H, 1H-
2. The composition according to claim 1, which is perfluorooctyl.
7. The enzyme electrode according to 6. 18. The fluoroalcohol ester of the polycarboxylic acid (A) is polyacrylic acid 1H, 1H, 2
The enzyme electrode according to claim 16, wherein the enzyme electrode is H, 2H-perfluorodecyl. 19. The fluoroalcohol ester of the polycarboxylic acid (A) has a molecular weight of 1,000 to 50,000.
The enzyme electrode according to any one of claims 8 to 18, wherein 20. An electrode comprising: an electrode provided on an insulating substrate; an immobilized enzyme layer formed on the electrode; and a restricted permeation layer formed on the immobilized enzyme layer. An enzyme electrode, wherein the permeable layer is mainly composed of a polycarboxylic acid ester compound having an alkyl alcohol ester group and a fluoro alcohol ester group. 21. When the number of fluorine atoms in the fluoroalcohol ester group is x and the number of hydrogen atoms is y, x
21. The enzyme electrode according to claim 20, wherein a fluorine content of the fluoroalcohol ester group represented by / (x + y) is 0.3 to 1. 22. The enzyme electrode according to claim 20, wherein the fluoroalcohol constituting the fluoroalcohol ester group has 3 to 15 carbon atoms. 23. The enzyme electrode according to claim 20, wherein the fluoroalcohol constituting the fluoroalcohol ester group is a primary alcohol. 24. The enzyme electrode according to claim 23, wherein the fluoro alcohol ester group is polymethacrylic acid 1H, 1H-perfluorooctyl. 25. The enzyme electrode according to claim 23, wherein the fluoroalcohol ester group is a polyacrylic acid 1H, 1H, 2H, 2H-perfluorodecyl group. 26. The enzyme electrode according to claim 20, wherein the alkyl alcohol ester group has 2 to 10 carbon atoms. 27. The enzyme electrode according to claim 26, wherein the alkyl alcohol ester group is polyhexyl methacrylate. 28. The thickness of the restricted permeation layer is from 0.01 to
The enzyme electrode according to any one of claims 1 to 27, wherein the thickness is 3 µm. 29. The enzyme electrode according to claim 1, further comprising a bonding layer mainly composed of a silane coupling agent between the electrode and the immobilized enzyme layer. 30. The enzyme electrode according to claim 29, wherein the silane coupling agent is γ-aminopropyltriethoxysilane. 31. The enzyme according to claim 29, further comprising an ion exchange resin layer mainly composed of an ion exchange resin having a perfluorocarbon skeleton between the binding layer and the immobilized enzyme layer. electrode. 32. A biosensor using the enzyme electrode according to claim 1 as a working electrode. 33. The biosensor according to claim 32, which is used for measuring glucose in urine. 34. A measuring device, comprising: the biosensor according to claim 32; and a data reporting unit that reports an electric signal obtained from the biosensor. 35. The biosensor according to claim 32 or 33, an electrochemical measurement circuit unit that obtains an electric signal from the biosensor, a data processing unit that calculates a measurement value based on the electric signal, A measuring device comprising: a data notifying unit for notifying a measured value. 36. The data processing section comprises: (a) clocking means; (b) time setting means for setting a measurement time; and time notifying means for notifying that the time set by the time setting means has come. ) Operation explanation means for explaining the operation method of the measuring instrument; (d) measured value storing means for storing the calculated measured value; (e) password registration means for registering the password of the user of the measuring instrument; (f) Memo registration means for registering memos,
(G) operation notifying means for detecting malfunction of the measuring instrument, (h)
A calibration time notifying means for detecting and notifying the calibration time of the enzyme electrode, (i) an electrode replacement time notifying means for detecting and notifying the replacement time of the enzyme electrode, and (j) an abnormal current value for detecting and notifying the abnormal current value 36. The measuring instrument according to claim 35, further comprising a part or all of the notifying means and (k) an electrode calibrating means for calibrating the enzyme electrode. 37. The data notifying unit may further include (a) to (d) in addition to the measurement value calculated by the data processing unit.
37. The measuring device according to claim 36, wherein a processing result obtained by one or more of (k) means is notified. 38. The measuring instrument according to claim 36, wherein a plurality of times can be set by the time setting means. 39. The measuring instrument according to claim 36, wherein said password registration means can register a plurality of passwords. 40. The measuring device according to claim 36, wherein said measured value storage means can store a plurality of measured values. 41. A memo registration means for calling a memo group registered in advance, a memo selection means for selecting a memo item to be registered from the called memo group, and a memo for calling the memo selected by the memo selection means. 41. The measuring device according to claim 36, further comprising a calling unit, wherein a plurality of memos can be registered. 42. The apparatus according to claim 3, further comprising a temperature sensor, wherein the measured value is corrected using the temperature of the measurement sample or the measurement environment measured by the temperature sensor.
42. The measuring device according to any one of 6 to 41. 43. The measurement according to claim 36, further comprising a pH sensor, wherein the measurement value is corrected using a pH value of a measurement sample measured by the pH sensor. vessel. 44. A data processing apparatus further comprising a communication processing unit connected to the data processing unit, wherein the data obtained by the data processing unit is transferred to the outside of the measuring device by the communication processing unit. A measuring device according to any one of claims 36 to 43. 45. The printing apparatus according to claim 36, further comprising a printing unit connected to the data processing unit, wherein the printing unit prints data obtained by the data processing unit.
45. The measuring instrument according to any one of to 44. 46. An external storage unit connected to the data processing unit, wherein the data obtained by the data processing unit is stored by the external storage unit. The measuring device according to any one of the above. 47. The measuring device according to claim 46, wherein the external storage unit uses a removable storage medium. 48. The measuring instrument according to claim 47, wherein the storage medium is a semiconductor storage medium, a magnetic storage medium, or an optical storage medium. 49. A method of notifying the data notifying unit includes a digital value, an analog value, a graphic, a voice, a sound, a vibration, a heat,
49. The measuring device according to claim 34, wherein the measuring device is light. 50. The measuring instrument according to claim 34, wherein said biosensor is detachably provided. 51. forming an electrode on an insulating substrate;
A step of applying a first solution containing an enzyme directly onto the electrode or through another layer, followed by drying to form an immobilized enzyme layer; and directly or on another layer of the immobilized enzyme layer. A second liquid containing a polymer in which a pendant group containing at least a fluoroalkylene block is bonded to a fluorine-free vinyl polymer, followed by drying to form a restricted permeation layer. A method for producing an enzyme electrode, comprising: 52. The method for manufacturing an enzyme electrode according to claim 51, wherein after forming the electrode, a bonding layer mainly composed of a silane coupling agent is formed, and then the immobilized enzyme layer is formed. . 53. The method for producing an enzyme electrode according to claim 51, wherein the second liquid is applied by a spin coating method. 54. The method for producing an enzyme electrode according to claim 51, wherein after applying the second liquid by a dipping method, drying is performed while blowing nitrogen gas. 55. The method according to claim 5, wherein the thickness of the restricted transmission layer is 0.01 to 3 μm after drying.
55. The method for producing an enzyme electrode according to any one of 1 to 54.