Electrode, sensor, and method for manufacturing a sensor

Abstract

Provided is an electrode comprising a surface part that makes it possible to accurately form, on a prescribed region, a reagent layer having designed dimensions. An electrode (10) comprises: a surface part (11); a first region (110) that is formed on the surface part (11), that includes a first outer periphery part (111), and that has first surface free energy; a second region (120) that is formed on the surface part (11), that surrounds the first region (110), that includes a second inner periphery part (121) which is in contact with the first outer periphery part (111) of the first region (110) and a second outer periphery part (122) which is located more outward than the second inner periphery part (121), and that has second surface free energy higher than the first surface free energy; and a third region(130) that surrounds the second region (120), that includes a third inner periphery part (131) which is in contact with the second outer periphery part (122) of the second region (120), and that has third surface free energy lower than the second surface free energy.

Description

Technical Field

[0001] The present invention relates to, for example, electrodes, sensors, and methods for manufacturing sensors.

Background Art

[0002] Electrochemical sensors have been conventionally used to measure target substances in test samples such as cell culture solutions and blood samples. Such sensors typically include an insulating substrate and a working electrode disposed on the surface of the substrate. The working electrode typically includes an electrode and a reagent layer disposed on the electrode and containing a reagent (such as a redox enzyme and an electron transfer substance) involved in a redox reaction.

[0003] For example, Patent Document 1 describes a biosensor for detecting the presence of a target substance contained in a liquid sample, including an insulating substrate having a recess formed in a portion thinner than the surroundings, a working electrode and a counter electrode at least one of which is disposed in the recess, and a reaction reagent disposed in the recess and reacting with a specific substance in the liquid sample. In the example of Patent Document 1, it is described that a circular recess was formed on the surface of a polyethylene terephthalate substrate, the working electrode was formed in the recess, and then the reagent layer was formed.

Prior Art Documents

Patent Documents

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the above - mentioned conventional sensors including a working electrode containing an electrode and a reagent layer disposed in a recess of an insulating substrate have the following problems.

[0006] The detection sensitivity of a test substance by a sensor equipped with a working electrode depends on the amount and density of the reagent contained in the reagent layer on the working electrode, the contact area between the working electrode and the reagent layer, and so on. Therefore, in order to improve the accuracy of detecting a test substance by a sensor equipped with a working electrode, it is necessary to form a reagent layer with uniform dimensions (area, thickness, and shape) on the electrode. In the biosensor described in Patent Document 1, the dimensions of the reagent layer on the working electrode and the contact area between the working electrode and the reagent layer may vary depending on the position and shape of the electrode within the recess of the insulating substrate, making it difficult to accurately form a reagent layer of the designed dimensions on a predetermined area of ​​the electrode surface.

[0007] The object of the present invention is to provide an electrode having a surface portion capable of accurately forming a reagent layer of designed dimensions on a predetermined area, a sensor including the same, and a method for manufacturing the sensor. [Means for solving the problem]

[0008] The present invention An electrode placed on an insulating substrate, A surface portion located on the opposite side of the substrate when placed on the substrate, A first region formed on the surface, including a first outer peripheral edge, wherein at least a portion of it has a first surface free energy, A second region is formed on the surface, including a second inner peripheral edge that surrounds the first region and is in contact with the first outer peripheral edge of the first region, and a second outer peripheral edge located outside the second inner peripheral edge, and having a second surface free energy greater than the first surface free energy, A third region is formed on the surface, including a third inner peripheral edge that surrounds the second region and is in contact with the second outer peripheral edge of the second region, and having a third surface free energy smaller than the second surface free energy, Electrode inside, Regarding.

[0009] The present invention also, An electrode placed on an insulating substrate, A surface portion located on the opposite side of the substrate when placed on the substrate, A first region formed on the surface, including a first outer peripheral edge, wherein at least a portion of it has a first surface free energy, A second region is formed on the surface, including a second inner peripheral edge that surrounds the first region and is in contact with the first outer peripheral edge of the first region, and a second outer peripheral edge located outside the second inner peripheral edge, and having a second surface free energy greater than the first surface free energy, An insulating layer, at least a portion of which is disposed on the surface portion, is formed on the first region and the second region, has an inner peripheral edge that defines the second peripheral edge of the second region, and includes an opening that penetrates in the thickness direction, Electrode inside, Regarding.

[0010] The present invention also, The electrode and, A reagent layer comprising a reagent involved in a redox reaction, the first region and the second region of the electrode, the outer peripheral edge located on the second outer peripheral edge of the second region, and the reagent layer, A sensor equipped with Regarding.

[0011] The present invention also, The electrode and, A reagent layer comprising a reagent involved in a redox reaction, the first region and the second region of the electrode, the outer peripheral edge located on the second outer peripheral edge of the second region, and the reagent layer, A method for manufacturing a sensor comprising: The reagent layer is formed by applying a first liquid composition containing the reagent in a first solvent to the first and second regions of the electrode and then drying it. Methods including Regarding.

[0012] The present invention also, The electrode and, A reagent layer disposed on the first region and the second region of the electrode, including an outer peripheral edge portion located on the second outer peripheral edge portion of the second region and a reagent involved in a redox reaction. A protective film covering the reagent layer. A method for manufacturing a sensor comprising: Applying a first liquid composition containing the reagent in a first solvent onto the first region and the second region of the electrode and then drying to form the reagent layer, and Applying a second liquid composition containing a protective film component in a second solvent onto the surface portion of the electrode so as to cover the reagent layer and then drying to form the protective film. A method including the above steps. Relates to.

[0013] A preferred embodiment of the present invention is An electrode disposed on an insulating substrate, A surface portion located on the side opposite to the substrate when disposed on the substrate, A first region formed on the surface portion, including a first outer peripheral edge portion and having at least a part with a first surface free energy, A second region formed on the surface portion, surrounding the first region, including a second inner peripheral edge portion contacting the first outer peripheral edge portion of the first region and a second outer peripheral edge portion located outside the second inner peripheral edge portion, and having a second surface free energy larger than the first surface free energy, A third region formed on the surface portion, surrounding the second region, including a third inner peripheral edge portion contacting the second outer peripheral edge portion of the second region and a third outer peripheral edge portion located outside the third inner peripheral edge portion, and having a third surface free energy smaller than the second surface free energy, A fourth region formed on the surface portion, surrounding the third region, including a fourth inner peripheral edge portion contacting the third outer peripheral edge portion of the third region and a fourth outer peripheral edge portion located outside the fourth inner peripheral edge portion, and having a fourth surface free energy larger than the third surface free energy, An insulating layer is formed on the first, second, third, and fourth regions, at least a portion of which is disposed on the surface, and includes an opening that penetrates in the thickness direction and has an inner peripheral edge that contacts the fourth peripheral edge of the fourth region in a plan view from a direction perpendicular to the surface, Electrode inside, Regarding.

[0014] Another preferred embodiment of the present invention is, A method for manufacturing the electrode comprising the surface portion, the first region, the second region, the third region, the fourth region, and the insulating layer, To provide an untreated electrode comprising an untreated surface portion having an untreated area in part for forming the first, second, third, and fourth regions and having the first surface free energy, and an insulating layer having an opening formed on the untreated area and penetrating in the thickness direction, at least a portion of which is disposed on the untreated surface portion, and In the untreated electrode, within the untreated region of the untreated surface, a laser beam is irradiated onto an annular fourth untreated region located on the outer periphery of the untreated region, adjacent to the inner peripheral edge of the opening of the insulating layer, in a plan view from a direction perpendicular to the untreated surface, and an annular second untreated region located further inward than the fourth untreated region, thereby converting the fourth untreated region into the fourth region and converting the second untreated region into the second region. Methods including This relates to the electrode obtained by this method, preferably, the third surface free energy is the same as the first surface free energy, the first untreated region which is the part of the untreated region that is inside the second untreated region becomes the first region having the first surface free energy, and the third untreated region which is the part of the untreated region that is between the second untreated region and the fourth untreated region becomes the third region having the same third surface free energy as the first surface free energy. [Effects of the Invention]

[0015] The electrode according to the present invention can accurately form a reagent layer of a designed size on the first and second regions formed on its surface.

[0016] The sensor according to the present invention can detect the substance to be tested.

[0017] According to the sensor manufacturing method of the present invention, a sensor having reagent layers of designed dimensions on the first and second regions of an electrode can be efficiently manufactured.

[0018] An electrode according to a preferred embodiment of the present invention, comprising a surface portion, a first region, a second region, a third region, a fourth region, and an insulating layer, can accurately form a reagent layer of designed dimensions on the first region and the second region, and can also accurately form a protective film covering the reagent layer, the third region, and the fourth region.

[0019] According to another preferred embodiment of the present invention, a method for manufacturing an electrode comprising a surface portion, a first region, a second region, a third region, a fourth region, and an insulating layer, it is easy to accurately form each of the first region, the second region, the third region, and the fourth region at the designed position. [Brief explanation of the drawing]

[0020] [Figure 1] A plan view showing a substrate with two electrodes, a reference electrode conductive layer, a counter electrode, and wiring arranged on it. [Figure 2] A plan view showing a substrate in which a first region and a second region are formed on the surface of each of the two electrodes in Figure 1. [Figure 3] Figure 2 is a plan view showing a substrate with an additional insulating layer. [Figure 4] Figure 3 is a plan view showing a substrate on which a reagent layer is further arranged on the electrode. [Figure 5] Plan view of a sensor relating to one embodiment of the present invention. [Figure 6] Figure 5 is a schematic diagram illustrating a method for measuring a test substance by immersing the sensor shown in Figure 5 in a liquid sample containing cells. [Figure 7] Figure 2 shows a magnified view of the portion of the electrode according to one embodiment of the present invention, including the first and second regions, enclosed by a dashed line. [Figure 8] Cross-sectional view of the electrode shown in Figure 7 along the line D-D'. [Figure 9] A cross-sectional view showing a first liquid composition containing reagents involved in the oxidation-reduction reaction in the first solvent, coated on the first and second regions of the electrode shown in Figure 8. [Figure 10] A cross-sectional view showing the reagent layers placed on the first and second regions of the electrode, formed by drying the first liquid composition shown in Figure 9. [Figure 11] A cross-sectional view of the sensor shown in Figure 5, along the line A-A', of the portion including the working electrode (electrode, reagent layer, and protective film). [Figure 12] A cross-sectional view of the sensor shown in Figure 5, along the line B-B', of the portion including the reference electrode (including the reference electrode conductive layer, silver / silver chloride layer, and protective film). [Figure 13] A cross-sectional view of the sensor shown in Figure 5, along the C-C' line, including the counter electrode. [Figure 14] A plan view of a portion of an electrode according to another embodiment of the present invention, including a first region and a second region. [Figure 15] A plan view of a portion of an electrode according to yet another embodiment of the present invention, including a first region and a second region. [Figure 16] A plan view of a portion of an electrode according to yet another embodiment of the present invention, including a first region and a second region. [Figure 17] A plan view of a portion of an electrode according to yet another embodiment of the present invention, including a first region, a second region, a third region, and a fourth region. [Figure 18] A cross-sectional view of the electrode shown in Figure 17, along the E-E' line. [Figure 19] A cross-sectional view showing a first liquid composition containing reagents involved in the oxidation-reduction reaction in a first solvent, which is coated on the first and second regions of the electrode shown in Figure 18. [Figure 20] A cross-sectional view showing the reagent layers placed on the first and second regions of the electrode, formed by drying the first liquid composition shown in Figure 19. [Figure 21] A cross-sectional view showing a second liquid composition containing a protective film component in a second solvent, coated to form a reagent layer on the first, second, third, and fourth regions of the electrode shown in Figure 20. [Figure 22] A cross-sectional view showing a protective film formed by drying the second liquid composition shown in Figure 21, which is placed on the first, second, third, and fourth regions of the electrode to cover the reagent layer. [Figure 23] A plan view of a portion of an electrode according to yet another embodiment of the present invention, including an opening in the insulating layer, a first region, and a second region. [Figure 24] Cross-sectional view of the electrode shown in Figure 23 along the F-F' line. [Figure 25] A cross-sectional view of a sensor according to one embodiment of the present invention, in which a reagent layer and a protective film are arranged on the first and second regions within the opening of the insulating layer of the electrode shown in Figure 23. [Figure 26] Control block diagram of an analytical device including a sensor according to one embodiment of the present invention. [Figure 27] A photograph showing the results of Experiment 1. [Figure 28] A photograph showing the results of Experiment 3. [Figure 29A] Figure 29A shows the results of 12 days of continuous measurement of the current value of a sensor coated with 0.40 mg of the lactate oxidase-containing liquid composition used to prepare the reagent layer in Experiment 5. [Figure 29B] Figure 29B shows the results of 12 days of continuous measurement of the current value of a sensor coated with 0.45 mg of the lactate oxidase-containing liquid composition used to prepare the reagent layer in Experiment 5. [Figure 29C] Figure 29C shows the results of 12 days of continuous measurement of the current value of a sensor coated with 0.50 mg of the lactate oxidase-containing liquid composition used to prepare the reagent layer in Experiment 5. [Figure 29D] Figure 29D shows the results of 12 days of continuous measurement of the current value of a sensor coated with 0.55 mg of the lactate oxidase-containing liquid composition used to prepare the reagent layer in Experiment 5. [Figure 29E]Figure 29E shows the results of 12 days of continuous measurement of the current value of a sensor coated with 0.60 mg of the lactate oxidase-containing liquid composition used to prepare the reagent layer in Experiment 5. [Figure 30] A plan view of an electrode according to yet another embodiment of the present invention, including an opening in the insulating layer and a portion comprising a first region, a second region, a third region, and a fourth region. [Figure 31] Cross-sectional view of the electrode shown in Figure 30, along the G-G' line. [Figure 32] A cross-sectional view of an operating electrode (sensor) according to one embodiment of the present invention, in which a reagent layer is placed on the first and second regions within the opening of the insulating layer of the electrode shown in Figure 30, and a protective film is placed on the reagent layer, the third region and the fourth region. [Figure 33] Cross-sectional view of an untreated electrode for manufacturing the electrode shown in Figure 30. [Figure 34] A schematic diagram of a portion of the untreated electrode shown in Figure 33, in a plan view from a direction perpendicular to the untreated surface, including the boundary between the untreated area of ​​the untreated surface and the insulating layer around the opening. [Figure 35] A schematic diagram of a portion of the electrode obtained by converting the fourth untreated region of the untreated surface area of ​​the untreated electrode shown in Figure 34 to a fourth region, and converting the second untreated region of the untreated surface area to a second region. [Figure 36] A schematic diagram of a portion of the electrode obtained by converting the portion of the untreated surface exposed by destroying the area around the opening of the insulating layer with laser light irradiation into the fourth region, in addition to the fourth untreated region of the untreated area of ​​the untreated surface shown in Figure 34, and converting the second untreated region of the untreated area of ​​the untreated surface into the second region. [Figure 37]The upper left of Figure 37 shows a photograph of the electrode created in Experiment 6-2 (including a circular second region and a third region surrounding it within the opening of the insulating layer) after laser irradiation. The lower left of Figure 37 shows a photograph of the working electrode obtained by forming a reagent layer and a protective film on the electrode created in Experiment 6-2. The upper right of Figure 37 shows a photograph of the electrode created in Experiment 6-1 (including a circular second region, a third region surrounding it, and a fourth region surrounding it within the opening of the insulating layer) after laser irradiation. The lower right of Figure 37 shows a photograph of the working electrode obtained by forming a reagent layer and a protective film on the electrode created in Experiment 6-1. [Figure 38] Figure 38 (left) shows the measurement results of the thickness of the protective film on the working electrode obtained by forming a reagent layer and a protective film on the electrode prepared in Experiment 6-2. Figure 38 (right) shows the measurement results of the thickness of the protective film on the working electrode obtained by forming a reagent layer and a protective film on the electrode prepared in Experiment 6-1. [Modes for carrying out the invention]

[0021] The following describes embodiments of the electrode, sensor, and method for manufacturing the sensor according to the present invention. In these embodiments, unnecessary details may be omitted. For example, detailed explanations of already well-known matters and redundant explanations of substantially identical configurations may be omitted. This is to avoid the following explanation becoming unnecessarily verbose and to facilitate understanding by those skilled in the art.

[0022] Furthermore, the applicant provides the accompanying drawings and the following description so that those skilled in the art may fully understand the present invention, and not intends to limit the subject matter described in the claims. This specification includes the disclosures of Japanese Patent Application No. 2022-124198, which forms the basis of the priority claim of this application. Furthermore, all publications, patents, and patent applications cited herein shall be incorporated herein by direct reference.

[0023] <Material> Examples of materials that can be used in electrodes and sensors disclosed herein are described below. The material of the insulating substrate on which the electrodes disclosed herein are placed is not particularly limited, but for example, resin materials such as polyethylene terephthalate, polycarbonate, polyimide, polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyoxymethylene, monomer cast nylon, cycloolefin polymer, polyethylene naphthalate, polybutylene terephthalate, methacrylic resin, ABS resin, or glass materials can be used. Preferably, polyethylene terephthalate, polycarbonate, and polyimide are used, and more preferably polyethylene terephthalate. The dimensions such as the thickness of the substrate are not particularly limited, but a substrate with a thickness of, for example, 0.05 mm or more and 2 mm or less, preferably 0.1 mm or more and 1 mm or less, can be used.

[0024] The electrodes disclosed herein can be formed from conductive materials such as carbon, gold, platinum, and palladium. Suitable carbon materials include glassy carbon, carbon black, graphite, diamond-like carbon, graphene, carbon nanotubes, and fullerenes. Preferably, the electrodes disclosed herein are layers of conductive material (conductive layers). The conductive layers can be formed from such conductive materials using methods such as sputtering, vapor deposition, and screen printing. The conductive layers can be processed into predetermined patterns using laser trimming, if necessary.

[0025] The reference electrode conductive layer, counter electrode, and wiring of the sensor disclosed herein may also be made of the same conductive material as described above.

[0026] The electrodes and sensors disclosed herein may include an insulating layer. The insulating layer preferably includes a water-repellent surface. Here, a water-repellent surface refers to a surface with a contact angle to water of, for example, 90° or more, more preferably 100° or more, and most preferably 110° or more. The upper limit of the contact angle to water of the water-repellent surface of the insulating layer is not particularly limited, but can be, for example, 160° or less. That is, the contact angle to water of the water-repellent surface of the insulating layer is, for example, 90° or more and 160° or less, and preferably can be within an even narrower range defined by the upper and / or lower limits. The contact angle to water of the surface of the insulating layer can be measured at 20°C. The contact angle to water of the surface of the insulating layer can be measured using a commercially available analytical device, for example, a KRUSS Handy Contact Angle / Surface Free Energy Analyzer MSA. Preferably, the contact angle to water of the surface is measured by dispensing 1 μL of water droplets onto the surface to be measured and measuring the contact angle between the droplet and the surface after 2 seconds.

[0027] The insulating layer of the electrodes and sensors disclosed herein preferably contains a fluororesin. As the fluororesin, polymer compounds of fluorinated hydrocarbons can be used, for example, polymer compounds containing one or more selected from vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene, and perfluoro(alkyl vinyl ether), and particularly preferably a copolymer containing two or more selected from vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene, and perfluoro(alkyl vinyl ether), and more preferably a copolymer containing vinylidene fluoride and hexafluoropropylene. The insulating layer can be entirely composed of a fluororesin.

[0028] Another preferred example of an insulating layer provided in the electrodes and sensors disclosed herein is an insulating layer comprising a compound containing a perfluoroalkyl group. Examples of compounds containing a perfluoroalkyl group include fluorine-based surface modifiers. An insulating layer comprising a compound containing a perfluoroalkyl group can be formed by coating a composition containing an insulating matrix resin and a compound containing a perfluoroalkyl group (fluorine-based surface modifier) ​​in a solvent and drying it. The insulating layer thus formed is preferably a layer of insulating matrix resin containing a compound containing a perfluoroalkyl group on its surface. The type of insulating matrix resin is not particularly limited, but may be, for example, a polyester resin. The number of carbon atoms in the perfluoroalkyl group is not particularly limited, but may be in the range of 2 to 20 carbon atoms, for example. The perfluoroalkyl group may contain a trifluoromethyl group at its terminus.

[0029] The insulating layer may have a single-layer structure consisting of one type of insulating layer, or it may have a laminated structure in which two or more insulating layers are stacked.

[0030] The sensors disclosed herein are used to detect a predetermined test substance in a liquid sample by immersion in the sample. The liquid sample is preferably a liquid sample containing water as a solvent. Examples of liquid samples include cell culture media and liquid samples prepared using blood obtained from living organisms. Examples of test substances include glucose, lactic acid, cholesterol, bilirubin, amino acids such as glutamine and glutamic acid, glycated amino acids, glycated peptides, ketone bodies (3-hydroxybutyric acid), and alcohols.

[0031] The sensor disclosed herein comprises a working electrode comprising an electrode disclosed herein and a reagent layer containing a reagent involved in the redox reaction. The reagent involved in the redox reaction may be any reagent involved in the redox reaction with the test substance, and can be appropriately selected depending on the test substance. The reagent involved in the redox reaction may be a combination of an oxidoreductase and a mediator (electron transfer substance), or may include an oxidoreductase. The oxidoreductase may include a coenzyme.

[0032] Oxidoreductases include oxidases and dehydrogenases. Specific examples of oxidoreductases include glucose oxidase, lactate oxidase, cholesterol oxidase, bilirubin oxidase, glucose dehydrogenase, lactate dehydrogenase, amino acid oxidase, amino acid dehydrogenase, glutamate oxidase, glutamate dehydrogenase, fructosyl amino acid oxidase, fructosyl peptide oxidase, 3-hydroxybutyrate dehydrogenase, alcohol oxidase, and alcohol dehydrogenase. These oxidoreductases can be used to detect the test substances exemplified above.

[0033] Furthermore, the mediator may be one or more selected from, but is not limited to, metal complexes (e.g., osmium complexes, ruthenium complexes, iron complexes, etc.), quinone compounds (e.g., benzoquinone, naphthoquinone, phenanthrenequinone, phenanthrolinequinone, anthraquinone, and their derivatives, etc.), phenazine compounds, viologen compounds, phenothiazine compounds, and phenol compounds. Specific examples of mediators include one or more selected from potassium ferricyanide, hexaammineruthenium, ferrocene, poly(1-vinylimidazole)-bis(bipyridine)chloroosmium, hydroquinone, 2-methyl-1,4-benzoquinone, 1,2-naphthoquinone-4-sulfonate, 9,10-phenanthrenequinone-2-sulfonate, 9,10-phenanthrenequinone-2,7-disulfonate, 1,10-phenanthroline-5,6-dione, anthraquinone-2-sulfonate, phenazine derivatives (such as 1-methoxy-5-methylphenadinium methyl sulfate and 1-methoxy-5-ethylphenadinium ethyl sulfate), methyl viologen, benzyl viologen, methylene blue, methylene green, 2-aminophenol, 2-amino-4-methylphenol, and 2,4-diaminophenol. Examples of the salts mentioned above, though not limited to them, include sodium salts, potassium salts, calcium salts, magnesium salts, and lithium salts.

[0034] From the viewpoint of sensor durability and suppression of leakage outside the sensor, it is desirable that the mediator be a polymerized mediator bonded to a polymer compound. The polymer compound to which the mediator is bonded can be a homopolymer, a random copolymer, a block copolymer, or a polymer compound to which these are bonded or mixed. The weight-average molecular weight of the polymer compound is, for example, 10,000 or more, preferably 50,000 or more, and more preferably 100,000 or more, and the upper limit of the weight-average molecular weight is, for example, less than 10,000,000, preferably less than 1,000,000. That is, the weight-average molecular weight of the polymer compound can be 10,000 or more and less than 10,000,000, and preferably even narrower than the upper and / or lower limits. Furthermore, the polymer compound is not particularly limited, but examples include those in which multiple atoms selected from at least one of carbon atoms, nitrogen atoms, oxygen atoms, and sulfur atoms are bonded in a chain to form the main chain. Specific examples include natural polymer compounds such as proteins, polypeptides, and polynucleotides, as well as synthetic polymer compounds such as polyamino acids, polyimines, polyallyl compounds, poly(meth)acrylates, polyalkylene oxides, and copolymers thereof. Examples of polyamino acids include poly(L-glutamic acid) and poly(L-lysine). Examples of polyimines include polyalkyleneimines such as polyethyleneimine and polypropyleneimine. Examples of polyallyl compounds include polyallylamine and polydiallylamine. Examples of polyalkylene oxides include polyethylene oxide and polypropylene oxide. It is preferable that the entire polymerized mediator be hydrophilic, and further preferable that the polymer compound to which the mediator is bound is hydrophilic.

[0035] The reagent layer of the sensor disclosed herein may further include, in addition to the reagent, components such as a buffer, a hydrophilic polymer compound, a conductive carbon filler, and a crosslinking agent. Examples of hydrophilic polymer compounds include cellulose derivatives, one or more of which are selected from methylcellulose, carboxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxyethylmethylcellulose, and hydroxypropylmethylcellulose. Examples of conductive carbon fillers include one or more of which are selected from carbon black, graphite powder, porous carbon, and nanocarbon.

[0036] The reagent layer of the sensor disclosed herein can be formed by coating a first liquid composition containing reagents involved in the redox reaction into a first solvent and drying it. The first liquid composition may further contain the components described above as components included in the reagent layer. The first solvent included in the first liquid composition may be a solvent capable of dissolving the reagent, and examples include a solvent containing one or more selected from water and alcohols, preferably one or more selected from water and alcohols, more preferably water or a mixed solvent of water and alcohol, and most preferably water. Examples of alcohols include monohydric alcohols having 1 to 5 carbon atoms, with methanol, ethanol, or isopropyl alcohol being particularly preferred, and ethanol being most preferred.

[0037] The sensors disclosed herein may further comprise a protective film covering the reagent layer. The protective film may prevent or suppress the leakage of the reagent contained in the reagent layer to the outside of the protective film, and may be permeable to the test substance present outside the protective film. A protective film having such properties preferably contains a polymer compound. Examples of polymer compounds contained in the protective film include polymer compounds containing 4-vinylpyridine as a constituent unit, and polymer compounds containing cation-exchange functional groups such as proton-conducting groups.

[0038] Polymer compounds containing 4-vinylpyridine as a constituent unit include poly(4-vinylpyridine), copolymers of 4-vinylpyridine and alkyl methacrylate (preferably block copolymers), and copolymers of styrene, 4-vinylpyridine, and oligopropylene glycol methyl ether methacrylate (preferably random copolymers). Examples of the alkyl methacrylate include tert-butyl methacrylate. Examples of the oligopropylene glycol methyl ether methacrylate include tripropylene glycol methyl ether methacrylate. Polymer compounds containing 4-vinylpyridine as a constituent unit are preferably crosslinked with a crosslinking agent such as polyethylene glycol diglycidyl ether (PEGDGE). As the crosslinking agent, a crosslinking agent containing two or more epoxy groups, such as PEGDGE, can be used. Polymer compounds containing 4-vinylpyridine as a constituent unit, crosslinked with a crosslinking agent containing two or more epoxy groups, contain a quaternary ammonium cation-containing functional group produced by the reaction of a pyridyl group (tertiary amine) derived from 4-vinylpyridine with an epoxy group.

[0039] Polymer compounds containing cation-exchange functional groups such as proton-conducting groups include polymer compounds containing structural units having sulfonic acid groups in their side chains, preferably polymer compounds containing perfluoro compounds having sulfonic acid groups in their side chains as structural units, more preferably copolymer compounds containing perfluoro compounds having sulfonic acid groups in their side chains and perfluoro compounds not having ionic functional groups in their side chains as structural units, particularly preferably copolymers of tetrafluoroethylene and perfluoro[2-(fluorosulfonylethoxy)propyl vinyl ether], and especially preferably Nafion®. The protective film containing the polymer compound containing cation-exchange functional groups is preferably provided on the reagent layer to transport cations such as protons between the reagent layer and the liquid sample.

[0040] The protective film can be a laminate of two or more protective films, for example, a laminate of a protective film containing a polymer compound with cation-exchange functional groups, provided on the side in contact with a reagent layer containing a reagent that generates protons by the oxidation-reduction reaction of the test substance, and a protective film provided on top of it, containing a polymer compound with 4-vinylpyridine as a constituent unit.

[0041] Another preferred example of a protective film is one comprising a polymer compound containing 4-vinylpyridine as a constituent unit.

[0042] The reference electrode of the sensor disclosed herein may be provided with a protective film. The protective film of the reference electrode may be made of the materials described above with respect to the protective film of the working electrode.

[0043] The protective film provided in the sensors disclosed herein can be formed by coating a second liquid composition containing a protective film component into a second solvent and then drying it. Examples of the second solvent include alcohols or mixed solvents of alcohol and water. Examples of alcohols include monohydric alcohols having 1 to 5 carbon atoms, with methanol, ethanol, or isopropyl alcohol being particularly preferred, and ethanol being the most preferred. The protective film component is a component that can form a protective film after drying. The protective film component is, for example, one or more selected from polymer compounds constituting the protective film, their monomers, and their prepolymers, and may further contain a crosslinking agent.

[0044] <Surface free energy> In this specification, the "surface free energy" of a predetermined portion of the electrode surface is the surface free energy determined by the Owens-Wendt method. This surface free energy γs (mN / m) is the sum of the polar component γsp (mN / m) and the dispersion component γsd (mN / m).

[0045] Specifically, the polar component γsp (mN / m), the dispersion component γsd (mN / m), and the surface free energy γs (mN / m) can be calculated by measuring the contact angle (1 μL, measured 2 seconds after dropping) of a predetermined part of the electrode surface with respect to water and diiodomethane using a contact angle meter at 20°C and 40% relative humidity, and then using the following simultaneous equations (1), (2), and (3). Equation (1): γs = γsd + γsp Equation (2): 72.8(1+cosθH)=2(21.8γsd) 1 / 2 +2 (51.0 γsp) 1 / 2 Equation (3): 50.8(1+cosθI)=2(48.5γsd) 1 / 2 +2 (2.3γsp) 1 / 2 γs: Surface free energy γsd: Dispersion component of surface free energy γsp: Polar component of surface free energy θH: Contact angle with respect to water θI: Contact angle with respect to diiodomethane

[0046] The contact angle of a predetermined area on the electrode surface with respect to water and diiodomethane can be measured using a commercially available analytical device, for example, a handheld contact angle / surface free energy analyzer (MSA) manufactured by KRUSS. Preferably, at 20°C and 40% relative humidity, 1 μL each of water and diiodomethane droplets are dispensed onto the surface of the area to be measured, and the contact angle between the droplets and the surface is measured after 2 seconds.

[0047] In this specification, the second surface free energy is greater than the first surface free energy, and the difference is not limited. For example, the second surface free energy is preferably 3.0 mN / m or greater, more preferably 5.0 mN / m or greater, more preferably 7.0 mN / m or greater, more preferably 10.0 mN / m or greater, more preferably 12.0 mN / m or greater, and most preferably 15.0 mN / m or greater than the first surface free energy. There is no particular upper limit to the difference between the second surface free energy and the first surface free energy, but the difference can be, for example, 50 mN / m or less, preferably 30 mN / m or less. That is, the difference between the second surface free energy and the first surface free energy is, for example, 3.0 mN / m or more and 50 mN / m or less, and preferably can be within an even narrower range defined by the upper and / or lower limits. In the case described in this paragraph, with respect to the first liquid composition containing reagents involved in the redox reaction in the first solvent, the region of the electrode surface having a first surface free energy has relatively low wettability, while the region having a second surface free energy has relatively high wettability. Therefore, the dimensionally stable reagent layer can be formed on the first and second regions of the electrode, as described later.

[0048] In particular, it is preferable that the polar component of the second surface free energy is greater than the polar component of the first surface free energy. For example, the polar component of the second surface free energy is preferably 2.0 mN / m or more, more preferably 3.0 mN / m or more, more preferably 5.0 mN / m or more, more preferably 8.0 mN / m or more, and most preferably 11.0 mN / m or more, greater than the polar component of the first surface free energy. There is no particular upper limit to the difference between the polar component of the second surface free energy and the polar component of the first surface free energy, but the difference can be, for example, 40 mN / m or less, preferably 25 mN / m or less. That is, the difference between the polar component of the second surface free energy and the polar component of the first surface free energy is, for example, 2.0 mN / m or more and 40 mN / m or less, and preferably even narrower than the upper and / or lower limits defined above. In the case described in this paragraph, with respect to the first liquid composition containing reagents involved in the oxidation-reduction reaction in the first solvent, the region of the electrode surface having a first surface free energy has relatively low wettability, while the region having a second surface free energy has relatively high wettability. Therefore, the effect described later is particularly high, as it allows for the formation of a dimensionally stable reagent layer on the first and second regions of the electrode.

[0049] The value of the first surface free energy is not particularly limited, but for example it can be 20.0 mN / m or more, preferably 30.0 mN / m or more, more preferably 40.0 mN / m or more, and especially preferably 45.0 mN / m or more, and for example it can be 70.0 mN / m or less, preferably 60.0 mN / m or less, and more preferably 50.0 mN / m or less. That is, the value of the first surface free energy can be, for example, 20.0 mN / m or more and 70.0 mN / m or less, and preferably it can be in an even narrower range defined by the upper and / or lower limits. The value of the polar component of the first surface free energy is not particularly limited, but for example it can be 5.0 mN / m or less, preferably 3.0 mN / m or less, and for example it can be 0.0 mN / m or more, and preferably 2.0 mN / m or more. That is, the value of the polar component of the first surface free energy is 0.0 mN / m or more and 5.0 mN / m or less, and preferably can be in a narrower range defined by the upper and / or lower limits. The ratio of the dispersion component of the first surface free energy to the polar component (γsd / γsp) is, for example, 8.0 or more, preferably 10.0 or more, more preferably 12.0 or more, particularly preferably 15.0 or more, and can be, for example, 50.0 or less, preferably 30.0 or less. That is, the ratio of the dispersion component of the first surface free energy to the polar component is, for example, 8.0 or more and 50.0 or less, and preferably can be in a narrower range defined by the upper and / or lower limits. The surface region of the electrode having the first surface free energy described in this paragraph has high liquid repellency and low wettability to water and alcohol, especially water. Before the treatment to increase the surface free energy described later, an example of an electrode having the surface region having the first surface free energy described in this paragraph is a carbon electrode.

[0050] The value of the second surface free energy is not particularly limited, but for example it is 45.0 mN / m or more, preferably 50.0 mN / m or more, more preferably 55.0 mN / m or more, more preferably 59.0 mN / m or more, and especially preferably 60.0 mN / m or more, and can be, for example, 100.0 mN / m or less, preferably 80.0 mN / m or less, and more preferably 70.0 mN / m or less. That is, the value of the second surface free energy is, for example, 45.0 mN / m or more and 100.0 mN / m or less, and preferably it can be an even narrower range defined by the upper and / or lower limits. The value of the polar component of the second surface free energy is not particularly limited, but can be, for example, 5.0 mN / m or more, preferably 8.0 mN / m or more, more preferably 10.0 mN / m or more, and especially preferably 14.0 mN / m or more, and can be, for example, 50.0 mN / m or less, preferably 30.0 mN / m or less, and more preferably 20.0 mN / m or less. That is, the value of the polar component of the second surface free energy can be, for example, 5.0 mN / m or more and 50.0 mN / m or less, and preferably even narrower than the upper and / or lower limits defined above. The ratio of the dispersion component of the second surface free energy to the polar component (γsd / γsp) can be, for example, 10.0 or less, preferably 8.0 or less, more preferably 6.0 or less, and especially preferably 5.0 or less, and can be, for example, 1.0 or more. That is, the ratio of the dispersion component to the polar component of the second surface free energy is, for example, 1.0 or more and 10.0 or less, and preferably can be in an even narrower range defined by the upper and / or lower limits. The surface region of the electrode having the second surface free energy described in this paragraph has low liquid repellency and high wettability to water and alcohol, especially water.

[0051] In this specification, the third surface free energy is smaller than the second surface free energy. In other words, the second surface free energy is larger than the third surface free energy, and the specific difference can be selected from the same range as the difference between the second surface free energy and the first surface free energy described. In particular, it is preferable that the polar component of the second surface free energy is larger than the polar component of the third surface free energy, and the specific value of the difference can be selected from the same range as the value described for the difference between the polar component of the second surface free energy and the polar component of the first surface free energy. The value of the third surface free energy, the value of the polar component of the third surface free energy, and the ratio of the dispersion component of the third surface free energy to the polar component (γsd / γsp) can be selected from the range described for the value of the first surface free energy, the value of the polar component of the first surface free energy, and the ratio of the dispersion component of the first surface free energy to the polar component, respectively, and are particularly preferably the same as the value of the first surface free energy, the value of the polar component of the first surface free energy, and the ratio of the dispersion component of the first surface free energy to the polar component.

[0052] In this specification, the fourth surface free energy is greater than the third surface free energy. The fourth surface free energy may be the same as or different from the second surface free energy. The specific difference between the fourth surface free energy and the third surface free energy can be selected from the same range as the difference described for the difference between the second surface free energy and the first surface free energy. In particular, it is preferable that the polar component of the fourth surface free energy is greater than the polar component of the third surface free energy, and the specific value of this difference can be selected from the same range as the value described for the difference between the polar component of the second surface free energy and the polar component of the first surface free energy. The value of the fourth surface free energy, the value of the polar component of the fourth surface free energy, and the ratio of the dispersion component of the fourth surface free energy to the polar component (γsd / γsp) can be selected from the range described with respect to the value of the second surface free energy, the value of the polar component of the second surface free energy, and the ratio of the dispersion component of the second surface free energy to the polar component, respectively, and are particularly preferably the same as the value of the second surface free energy, the value of the polar component of the second surface free energy, and the ratio of the dispersion component of the second surface free energy to the polar component.

[0053] In this specification, the fifth surface free energy is smaller than the fourth surface free energy. In other words, the fourth surface free energy is larger than the fifth surface free energy, and the specific difference can be selected from the same range as the difference described for the difference between the second surface free energy and the first surface free energy. In particular, it is preferable that the polar component of the fourth surface free energy is larger than the polar component of the fifth surface free energy, and the specific value of the difference can be selected from the same range as the value described for the difference between the polar component of the second surface free energy and the polar component of the first surface free energy. The value of the fifth surface free energy, the value of the polar component of the fifth surface free energy, and the ratio of the dispersion component of the fifth surface free energy to the polar component (γsd / γsp) can be selected from the range described for the value of the first surface free energy, the value of the polar component of the first surface free energy, and the ratio of the dispersion component of the first surface free energy to the polar component, respectively, and are particularly preferably the same as the value of the first surface free energy, the value of the polar component of the first surface free energy, and the ratio of the dispersion component of the first surface free energy to the polar component.

[0054] In this specification, laser processing, plasma processing, corona discharge processing, and mask exposure are mentioned as treatments to increase the surface free energy of a specific region on the surface of an electrode, with laser processing being particularly preferred. These treatments are particularly preferred because they can form a region of the designed dimensions (outer shape and area) with high precision compared to printing methods, etc. Laser processing is a treatment that increases the surface free energy of a specific region on the surface of an electrode by scanning and irradiating it with laser light. Ultraviolet (UV) lasers and SHG (Second Harmonic Generation) lasers can be used as the laser light. UV lasers usually have a wavelength of 355 nm. Preferred examples of processing conditions with a UV laser are described in the examples. SHG lasers, for example, have a wavelength of 532 nm and have a green color in the visible light region. An example of processing conditions with an SHG laser is a wavelength of 532 nm, laser output of 450 mW, scan speed of 2000 mm / s, and frequency of 15 kHz.

[0055] <Electrode 10> An electrode 10 according to one embodiment of the present invention will be described with reference to Figures 2, 7, and 8. Figure 7 is an enlarged view of region X in Figure 2, and Figure 8 is a cross-sectional view along the line D-D' in Figure 7.

[0056] The electrode 10 is placed on an insulating substrate 20. Figures 2, 7, and 8 show the electrode 10 placed on the first surface 21 of the substrate 20.

[0057] The electrode 10 comprises a surface portion 11 located on the opposite side of the substrate 20 when placed on the substrate 20, and a first region 110 and a second region 120 formed on the surface portion 11.

[0058] The first region 110 includes the first outer peripheral edge 111. At least a portion of the first region 110 has a first surface free energy. In the electrode 10 according to the embodiment shown in Figures 2, 7, and 8, the entire first region 110 surrounded by the second region 120 has a first surface free energy. The portion of the first region 110 having a first surface free energy is not limited to the examples shown in Figures 2, 7, and 8. For example, all or part of the circumferential direction of the first outer peripheral edge 111 of the first region 110 may have a first surface free energy, and preferably, all or part of the circumferential direction of the first outer peripheral edge 111 and the portion adjacent to it on the inside may have a first surface free energy. Other preferred embodiments of the first region 110 will be described later with reference to Figures 14, 15, 16, etc.

[0059] The second region 120 is formed on the surface portion 11 and surrounds the first region 110. The second region 120 includes a second inner peripheral edge portion 121 that is in contact with the first outer peripheral edge portion 111 of the first region 110, and a second outer peripheral edge portion 122 that is located outside the second inner peripheral edge portion 121. The second region 120 has a second surface free energy that is greater than the first surface free energy.

[0060] The electrode 10 according to the embodiment shown in Figures 2, 7, and 8 further comprises a third region 130 formed on the surface portion 11, which includes a third inner peripheral portion 131 that surrounds the second region 120 and is in contact with the second outer peripheral portion 122 of the second region 120, and has a third surface free energy smaller than the second surface free energy.

[0061] The electrode 10 according to the embodiment shown in Figures 2, 7, and 8 can be manufactured by selectively applying a surface treatment to increase the surface free energy described in the <Surface Free Energy> column to the portion of the surface portion 11 (see Figures 7 and 8) of the electrode 10 that has a first surface free energy, thereby forming a second region 120 having a second surface free energy greater than the first surface free energy. At this time, the area outside the second region 120 becomes a third region 130 having a third surface free energy equal to the first surface free energy. In this embodiment, the entire first region 110 surrounded by the second region 120 has a first surface free energy.

[0062] In this embodiment, the first surface free energy, the second surface free energy, and the third surface free energy are as described in the <Surface Free Energy> column, respectively.

[0063] According to the embodiment shown in Figures 2, 7, and 8, by using an electrode 10 having a surface portion 11, a first region 110, a second region 120, and a third region 130, it is possible to accurately form a reagent layer 30 of the designed dimensions on the first region 110 and the second region 120. The contact area between the reagent layer 30 and the electrode 10 is defined by the first region 110 and the second region 120 of the electrode 10. This effect will be explained with reference to Figures 9 and 10.

[0064] As shown in Figure 9, a first liquid composition P containing reagents involved in the oxidation-reduction reaction in a first solvent is applied to the first region 110 and the second region 120 of the electrode 10. At this time, the electrode 10 may be placed on the first surface 21 of the substrate 20 beforehand. The first liquid composition P has relatively low wettability with respect to the first region 110, which has a first surface free energy, relatively high wettability with respect to the second region 120, which has a second surface free energy, and relatively low wettability with respect to the third region 130, which has a third surface free energy. Therefore, the first liquid composition P applied to the first region 110 and the second region 120 tends to remain on the central first region 110 and rises up, forming a droplet whose outer periphery is defined by the second outer edge 122 of the second region 120. The outward spreading of the first liquid composition P applied to the first region 110 and the second region 120 of the electrode 10 is prevented by the third inner edge 131 of the third region 130. Compared to solid circular regions with a second surface free energy formed in an island-like manner on a region of the electrode surface having a first surface free energy, as in the comparative example described later, the first region 110 and the second region 120 of such an electrode 10 can support a larger amount of the first liquid composition P as droplets, thus enabling the formation of a reagent layer 30 containing a larger amount of reagent. The greater the amount of reagent supported in the reagent layer 30, the longer the continuous measurement of the test substance can be performed (see Experiment 5).

[0065] Next, the first liquid composition P applied to the first region 110 and the second region 120 of the electrode 10 is dried to form a reagent layer 30 containing the reagent and an outer peripheral edge 31 located on the second outer peripheral edge 122 of the second region 120, which is positioned on the first region 110 and the second region 120 of the electrode 10, as shown in Figure 10. As shown in Figure 9, the outer periphery of the first liquid composition P applied to the first region 110 and the second region 120 of the electrode 10 is defined by the second outer peripheral edge 122 of the second region 120. Therefore, as shown in Figure 10, the outer peripheral edge 31 of the reagent layer 30 obtained by drying is also located on the second outer peripheral edge 122 of the second region 120. For this reason, the outer shape and area of ​​the reagent layer 30 can be adjusted by adjusting the outer shape and area of ​​the first region 110 and the second region 120. On the other hand, the thickness of the reagent layer 30 can be adjusted by adjusting the concentration of the reagent in the first liquid composition P and the amount of the first liquid composition P applied. In other words, according to the electrode 10 of this embodiment, it is possible to accurately form a reagent layer 30 of the designed dimensions on the first region 110 and the second region 120 formed on the surface portion 11 of the electrode 10. The contact area between the reagent layer 30 and the electrode 10 is defined by the first region 110 and the second region 120 of the electrode 10.

[0066] The first solvent contained in the first liquid composition P can be a solvent capable of dissolving the reagent, and examples include solvents containing one or more selected from water and alcohols. Preferred examples of the first solvent are as described in the <Materials> section.

[0067] As described above, the outward spreading of the first liquid composition P applied to the first region 110 and the second region 120 of the electrode 10 is prevented by the third inner peripheral edge 131 of the third region 130. The electrode 10 according to the embodiment shown in Figures 2, 7, and 8 has the advantage of being low cost, unlike the electrode 10 according to the embodiment shown in Figures 23 and 24, which will be described later, in which an insulating layer 50 is placed to prevent the outward spreading of the applied first liquid composition P.

[0068] In the electrode 10 according to the embodiment shown in Figures 2, 7, and 8, the maximum width M of the outer edge of the second region 120 (referring to the diameter in the illustrated example) can be appropriately adjusted according to the dimensions of the target reagent layer 30, for example, 300 μm or more and 5,000 μm or less, preferably 900 μm or more and 2,000 μm or less. The radial width N of the second region 120 can also be appropriately adjusted according to the dimensions of the target reagent layer 30, for example, 0.5% or more and 40% or less, preferably 5% or more and 30% or less of the maximum width M of the outer edge. The radial width N of the second region 120 can be, for example, 50 μm or more and 500 μm or less, preferably 90 μm or more and 400 μm or less.

[0069] <Sensor 1> Sensor 1 according to one embodiment of the present invention will be described with reference to the drawings. As shown in Figure 5 and its cross-sectional views in Figures 11, 12, and 13, the sensor 1 of this embodiment is Electrode 10 and, A reagent layer 30 containing a reagent involved in the oxidation-reduction reaction, which is located on the first region 110 and the second region 120 of the electrode 10, and is positioned on the second peripheral edge 31 located on the second peripheral edge 122 of the second region 120, It is equipped with.

[0070] In the sensor 1 of this embodiment, the electrode 10 and the reagent layer 30 constitute the working electrode 2. Preferably, the electrode 10 is placed on the first surface 21 of an insulating substrate 20.

[0071] Figure 11 is a cross-sectional view along the line A-A' of the portion of the sensor 1 including the working electrode 2 shown in Figure 5. A first region 110 and a second region 120 are formed on the surface portion 11 of the electrode 10 that is opposite to the substrate 20, and the reagent layer 30 is placed on the first region 110 and the second region 120. As shown in Figure 11, the sensor 1 further comprises a protective film 40 that covers the reagent layer 30. The protective film 40 prevents or suppresses leakage of the reagent contained in the reagent layer 30. The electrode 10 is connected to wiring 5 located on the first surface 21 of the substrate 20.

[0072] Specific examples of the materials for the electrode 10, substrate 20, reagent layer 30, and protective film 40 are as described in the <Materials> section.

[0073] The sensor 1 of this embodiment includes two working electrodes 2, but in another embodiment not shown, there may be only one working electrode or three or more. In a sensor 1 having two or more working electrodes 2, each reagent layer 30 of the two or more working electrodes 2 may contain reagents that are involved in the redox reaction of different test substances. For example, some of the two or more working electrodes 2 may have a reagent layer 30 containing a reagent that is involved in the redox reaction of lactic acid, and another part may have a reagent layer 30 containing a reagent that is involved in the redox reaction of glucose.

[0074] In the sensor 1 of this embodiment, the electrode 10 further comprises an insulating layer 50, at least a portion of which is disposed on the surface portion 11. The insulating layer 50 has openings 52 formed on the first region 110, the second region 120, and the third region 130 of the surface portion 11 of the electrode 10. In this embodiment, as shown in Figure 11, the reagent layer 30 and the protective film 40 are disposed within the openings 52. In addition to the surface portion 11 of the electrode 10, the insulating layer 50 also covers other portions of the first surface 21 of the substrate 20.

[0075] The sensor 1 of this embodiment may further include a reference pole 3 and / or a counter pole 4 disposed on the substrate 20, and preferably further includes a reference pole 3 and a counter pole 4 as shown in the illustrated example.

[0076] Figure 12 is a cross-sectional view along the line B-B' of the portion of the sensor 1 shown in Figure 5 that includes the reference electrode 3. The reference electrode 3 includes a reference electrode conductive layer 301 disposed on the first surface 21 of the substrate 20 and a silver / silver chloride layer 302 disposed on the reference electrode conductive layer 301. Preferably, the reference electrode 3 further includes a reference electrode protective film 303 disposed on the silver / silver chloride layer 302 as shown. Preferred embodiments of the materials for the reference electrode conductive layer 301 and the reference electrode protective film 303 are as described in the <Materials> section. Wiring 5 is connected to the reference electrode conductive layer 301 of the reference electrode 3. The insulating layer 50 has a reference electrode opening 53 formed in a position that overlaps with the reference electrode 3 in a plan view. The reference electrode conductive layer 301, the silver / silver chloride layer 302 and the reference electrode protective film 303 of the reference electrode 3 are arranged within the reference electrode opening 53 as shown in Figure 12.

[0077] Figure 13 is a cross-sectional view along the C-C' line of the portion of the sensor 1 shown in Figure 5 that includes the counter electrode 4. The counter electrode 4 is a conductive layer disposed on the first surface 21 of the substrate 20. Preferred embodiments of the material of the conductive layer constituting the counter electrode 4 are as described in the <Material> section. Wiring 5 is connected to the counter electrode 4. The insulating layer 50 has a counter electrode opening 54 formed in a position that overlaps with a portion of the upper surface 4a of the counter electrode 4 in a plan view. As shown in Figure 13, the counter electrode 4 is positioned within the counter electrode opening 54, and a portion of the upper surface 4a of the counter electrode 4 is exposed through the counter electrode opening 54.

[0078] As shown in Figure 6, Sensor 1 is used to detect a predetermined test substance in the liquid sample L by immersing it in the liquid sample L. Specific examples of the liquid sample and test substance are as described in the <Materials> section. In Figure 6, a cell culture medium containing cell C is shown as an example of the liquid sample L.

[0079] When the reagent layer 30 of the working electrode 2 of sensor 1 contains a reagent that oxidizes the test substance in the liquid sample L, electrons move from the test substance to the electrode 10 of the working electrode 2 under conditions where a predetermined voltage is applied to the working electrode 2, reference electrode 3, and counter electrode 4 of sensor 1. Similarly, when the reagent layer 30 contains a reagent that reduces the test substance in the liquid sample L, electrons move from the electrode 10 of the working electrode 2 to the test substance. Since the amount of electrons moved depends on the concentration of the test substance, the concentration or change in concentration of the test substance in the liquid sample L can be measured based on the current value or change in current value flowing through the electrode 10 of the working electrode 2 of sensor 1.

[0080] An example of an analytical apparatus 200 for analyzing a test substance in a liquid sample, equipped with a sensor 1, will be described with reference to Figure 26.

[0081] As shown in Figure 26, the analysis device 200 comprises a sensor 1, an analysis unit 202, and a control unit 204. The working pole 2, reference pole 3, and counter pole 4 of the sensor 1 are each connected to the analysis unit 202 via wiring 5. The analysis unit 202 can communicate with the control unit 204.

[0082] The analysis unit 202 includes an electrochemical measurement unit 211, a control unit 212, a storage unit 213, and a communication unit 214.

[0083] The electrochemical measurement unit 211 is a potentiostat that measures the concentration of a substance to be tested by applying a predetermined voltage to the working electrode 2, reference electrode 3, and counter electrode 4 of the sensor 1, and includes a voltage application unit 211a and a current measurement unit 211b, and preferably further includes a voltage measurement unit (counter electrode terminal voltage measurement unit) 211c.

[0084] The voltage application unit 211a applies a predetermined voltage to the working electrode 2, reference electrode 3, and counter electrode 4 of the sensor 1 in order to measure the concentration of the substance to be tested contained in the liquid sample L.

[0085] The current measuring unit 211b detects the current value or change thereof flowing between the working electrode 2 and the counter electrode 4 of the sensor 1, measured when a voltage is applied from the voltage application unit 211a to the working electrode 2, reference electrode 3, and counter electrode 4 of the sensor 1. As described above, the current value or change in current value detected by the current measuring unit 211b serves as an indicator of the concentration or change in concentration of the test substance in the liquid sample L.

[0086] The voltage measuring unit 211c measures the terminal voltage of the counter electrode 4 of the sensor 1.

[0087] The control unit 212 is connected to the voltage application unit 211a, the current measurement unit 211b, the voltage measurement unit 211c, the storage unit 213, and the communication unit 214. The control unit 212 controls the voltage application unit 211a to apply a predetermined voltage to the working pole 2, the reference pole 3, and the counter pole 4 of the sensor 1, and controls the communication unit 214 to transmit the measurement results from the current measurement unit 211b and the voltage measurement unit 211c to the control unit 204.

[0088] The memory unit 213 is connected to the control unit 212 and stores data such as the applied voltage value preset for each measurement target, the measured values ​​from the current measurement unit 211b and the voltage measurement unit 211c, and a pre-measured calibration curve.

[0089] The communication unit 214 is controlled by the control unit 212 and transmits data such as measurement results from the current measurement unit 211b and the voltage measurement unit 211c to the analysis unit 242 of the control unit 204.

[0090] The control unit 204 is capable of communicating with the analysis unit 202 via the communication unit 214 and includes a display unit 241 and an analysis unit 242.

[0091] The display unit 241 displays, for example, the concentration of the test substance in the liquid sample L, based on the current value detected by the current measurement unit 211b, as a result of the analysis performed by the analysis unit 242.

[0092] The analysis unit 242 is, for example, a PC (Personal Computer) that calculates the concentration of the test substance based on the current value flowing between the working electrode 2 and the counter electrode 4, which is measured in the current measurement unit 211b.

[0093] <Manufacturing method for sensor 1> An example of a method for manufacturing the sensor 1 according to the embodiment shown in Figure 5 will be described with reference to the drawings, particularly Figures 1 to 5. First, as shown in Figure 1, an electrode (working electrode conductive layer) 10, a reference electrode conductive layer 301, a counter electrode (counter electrode conductive layer) 4, and wiring 5 electrically connected to each of them are placed on the first surface 21 of an insulating substrate 20.

[0094] Next, as shown in Figure 2, a first region 110, a second region 120, and a third region 130 are formed on the surface portion 11 of the electrode 10 located on the side opposite to the substrate 20. If the entire surface portion 11 of the electrode 10 before processing has a first surface free energy, a portion of the surface portion 11 is designated as the first region 110, and the annular region surrounding the first region 110 is selectively subjected to the above-described process to increase the surface free energy, thereby forming a first region 110 having a first surface free energy, a second region 120 having a second surface free energy greater than the first surface free energy, and a third region 130 having a third surface free energy equal to the first surface free energy.

[0095] Next, as shown in Figure 3, an insulating layer 50 is laminated on the first surface 21 of the substrate 20 on which the electrode 10, reference electrode conductive layer 301, counter electrode 4, and wiring 5 are arranged. The insulating layer 50 has openings 52 formed on the first region 110, second region 120, and third region 130 of the surface portion 11 of the electrode 10, a reference electrode opening 53 formed on the reference electrode conductive layer 301, and a counter electrode opening 54 formed on the counter electrode 4.

[0096] Next, as shown in Figures 4 and 10, a reagent layer 30 is formed on the first region 110 and the second region 120 of the electrode 10 within the opening 52 of the insulating layer 50, including an outer peripheral edge 31 located on the second outer peripheral edge 122 of the second region 120 and a reagent involved in the oxidation-reduction reaction. The reagent layer 30 can be formed by applying a first liquid composition P containing the reagent in a first solvent to the first region 110 and the second region 120 of the electrode 10, as described above with reference to Figures 9 and 10, and then drying it. The preferred embodiment of the method for forming the reagent layer 30, the first solvent, the first liquid composition P, and the electrode 10 on which the reagent layer 30 is formed is as described above. The reagent layer 30 formed on the electrode 10 by this method contains many reagents. For this reason, the sensor 1 manufactured by the method according to this embodiment is suitable for a method of continuously detecting a test substance by immersing it in a liquid sample L for a long period of time.

[0097] Next, as shown in Figures 5 and 11, a protective film 40 is formed to cover the reagent layer 30. The protective film 40 can be formed by applying a second liquid composition containing a protective film component in a second solvent to the surface portion 11 of the electrode 10 so as to cover the reagent layer 30, and then drying it. In the example shown in Figures 5 and 11, the protective film 40 can be formed by applying the second liquid composition to the opening 52 of the insulating layer 50, which includes the reagent layer 30 formed on the surface portion 11 of the electrode 10, and then drying it. Alcohol can be used as an example of the second solvent. Specific examples of the second solvent, protective film component, polymer compound constituting the protective film, and crosslinking agent are as described in the <Materials> section.

[0098] Furthermore, as shown in Figures 5 and 12, the silver / silver chloride layer 302 and the reference electrode protective film 303 are laminated on the reference electrode conductive layer 301 within the reference electrode opening 53 of the insulating layer 50 to complete the reference electrode 3. The reference electrode protective film 303 can be formed in the same manner as the protective film 40 of the working electrode 2.

[0099] <Embodiment of electrode 10 shown in Figure 14> Another embodiment of the electrode 10 will be described with reference to Figure 14. Figure 14 is an enlarged view of the region of the electrode 10 according to this embodiment that corresponds to region X in the electrode 10 shown in Figure 2. The electrode 10 according to this embodiment, shown in Figure 14, comprises a surface portion 11, a first region 110 formed on the surface portion 11 having the following characteristics, and a second region 120 formed on the surface portion 11 having a second surface free energy greater than the first surface free energy. The electrode 10 according to this embodiment further comprises a third region 130 formed on the surface portion 11 having a third surface free energy less than the second surface free energy.

[0100] In the electrode 10 according to this embodiment, the first region 110 is Including the first outer peripheral edge 111, further, A central region 112 is located within the first region 110, includes an outer peripheral edge 113 that is located inside the first outer peripheral edge 111 of the first region 110, and has a surface free energy greater than the first surface free energy, A surrounding region 115 having a first surface free energy includes an inner peripheral edge 114 that surrounds the central region 112 and is in contact with the outer peripheral edge 113 of the central region 112, and a first outer peripheral edge 111, Includes.

[0101] In the electrode 10 according to this embodiment shown in Figure 14, the peripheral region 115 is the region of the first region 110 other than the central region 112, and includes the inner peripheral edge 114 that surrounds the central region 112 and is in contact with the entire outer peripheral edge 113 of the central region 112, and the entire first outer peripheral edge 111. Preferably, the central region 112 is positioned to include the centroid of the first region 110, and more preferably, the centroid of the central region 112 and the centroid of the first region 110 coincide.

[0102] In the electrode 10 according to this embodiment shown in Figure 14, the surface free energy of the central region 112 is greater than the first surface free energy. The specific difference between the surface free energy of the central region 112 and the first surface free energy can be selected from the same range as the difference described for the difference between the second surface free energy and the first surface free energy. In particular, it is preferable that the polar component of the surface free energy of the central region 112 is greater than the polar component of the first surface free energy, and the specific value of this difference can be selected from the same range as the value described for the difference between the polar component of the second surface free energy and the polar component of the first surface free energy. The value of the surface free energy of the central region 112, the value of the polar component of the surface free energy of the central region 112, and the ratio of the dispersion component of the surface free energy of the central region 112 to the polar component (γsd / γsp) can be selected from the range described for the second surface free energy, and are particularly preferably the same as the second surface free energy.

[0103] The electrode 10 according to this embodiment, shown in Figure 14, provides the following effects.

[0104] Unlike Figure 14, in the embodiment of the electrode 10 shown in Figure 7, where the entire first region 110 has a first surface free energy and the surrounding second region 120 has a second surface free energy, when applying the first liquid composition P to the first region 110 and the second region 120 as shown in Figure 9, a nozzle (not shown) is usually brought close to the first region 110, the first liquid composition P is dropped from the nozzle and applied, and then the nozzle is moved away from the electrode 10. At this time, in the electrode 10 according to the embodiment of Figure 7, the entire first region 110 has low wettability with respect to the first liquid composition P, so when the first liquid composition P is dropped, the height of the droplet of the first liquid composition P formed on the first region 110 becomes high and does not detach from the tip of the nozzle, and when the nozzle is moved away from the electrode 10, the first liquid composition P adhering to the nozzle may also detach from the electrode 10.

[0105] In the electrode 10 according to this embodiment shown in Figure 14, the first region 110 includes a central region 112 having a surface free energy greater than the first surface free energy, and a surrounding region 115 having the first surface free energy. The central region 112 has relatively higher wettability to the first liquid composition P compared to the surrounding region 115 of the first region 110. Therefore, when a nozzle is brought close to the central region 112 of the first region 110 and the first liquid composition P is dropped from the nozzle, the height of the droplet of the first liquid composition P on the central region 112 is low and it easily separates from the tip of the nozzle, and when the nozzle is moved away from the electrode 10, the possibility of the first liquid composition P separating from the electrode 10 together is low. Therefore, with the electrode 10 according to this embodiment shown in Figure 14, it is easy to apply the intended amount of the first liquid composition P to the first region 110 and the second region 120.

[0106] In the electrode 10 according to this embodiment shown in Figure 14, the maximum width M of the outer edge of the second region 120 (referring to the diameter in the illustrated example) and the radial width N of the second region 120 can be the same values ​​as M and N in the electrode 10 according to the embodiments shown in Figures 2, 7, and 8. The maximum width W of the central region 112 (referring to the diameter in the illustrated example) can be, for example, 0.5% or more and 30% or less, preferably 5% or more and 25% or less of the maximum width M of the outer edge of the second region 120. The maximum width W of the central region 112 can be, for example, 50 μm or more and 500 μm or less, preferably 90 μm or more and 300 μm or less.

[0107] <Embodiment of electrode 10 shown in Figure 15> Another embodiment of electrode 10 will be described with reference to Figure 15. The embodiment shown in Figure 15 is a modified example of the embodiment shown in Figure 14, and features common to the embodiment shown in Figure 14 will not be described.

[0108] In the electrode 10 according to this embodiment, the first region 110 is Including the first outer peripheral edge 111, further, A central region 112 is located within the first region 110, includes an outer peripheral edge 113 that is located inside the first outer peripheral edge 111 of the first region 110, and has a surface free energy greater than the first surface free energy, A surrounding region 115 having a first surface free energy includes an inner peripheral edge 114 that surrounds the central region 112 and is in contact with the outer peripheral edge 113 of the central region 112, and a first outer peripheral edge 111, A connecting region 116 having a surface free energy greater than the first surface free energy extends through the surrounding region 115, from a part of the outer peripheral edge 113 of the central region 112 to a part of the second inner peripheral edge 121 of the second region 120, which is opposite via the surrounding region 115. Includes.

[0109] The connecting region 116 extends radially from the first region 110. Preferably, the connecting region 116 includes a plurality of regions, for example, 3 to 10, as shown in the figure. Preferably, the plurality of connecting regions 116 are arranged at equal intervals in the circumferential direction of the first outer edge 111.

[0110] In the electrode 10 according to this embodiment shown in Figure 15, the peripheral region 115 is divided into multiple connection regions 116, each having a first surface free energy. In the electrode 10 according to this embodiment shown in Figure 15, the first outer peripheral edge 111 and the inner peripheral edge 114 are also divided into multiple connection regions 116.

[0111] The surface free energy of the central region 112 and the surface free energy of the connecting region 116 are each greater than the first surface free energy. The surface free energy of the central region 112 and the surface free energy of the connecting region 116 may be the same or different, but are preferably the same. The surface free energy of the central region 112 and the surface free energy of the connecting region 116 may be the same or different as the second surface free energy of the second region 120, but are preferably both the same as the second surface free energy of the second region 120. The preferred range for the surface free energy of the central region 112 is as described with respect to the embodiment shown in Figure 14. The specific difference between the surface free energy of the connecting region 116 and the first surface free energy can be selected from the same range as the difference described for the difference between the second surface free energy and the first surface free energy. In particular, it is preferable that the polar component of the surface free energy of the connecting region 116 is greater than the polar component of the first surface free energy, and the specific value of this difference can be selected from the same range as the value described for the difference between the polar component of the second surface free energy and the polar component of the first surface free energy. The surface free energy value of the connection region 116, the value of the polar component of the surface free energy of the connection region 116, and the ratio of the dispersion component of the surface free energy of the connection region 116 to the polar component (γsd / γsp) can be selected from the range described with respect to the second surface free energy, and are particularly preferably the same as the second surface free energy.

[0112] The electrode 10 according to this embodiment, shown in Figure 15, has the following effects. Compared to the surrounding region 115 of the first region 110, which has a first surface free energy, the central region 112, connecting region 116, and second region 120, which have higher surface free energy, have relatively high wettability to the first liquid composition P. Therefore, the first liquid composition P dropped from the nozzle onto the central region 112 of the first region 110 can easily spread from the central region 112, through the connecting region 116, to the second region 120. Therefore, with the electrode 10 according to this embodiment, when the nozzle is brought close to the central region 112 of the first region 110, the first liquid composition P is dropped from the nozzle, and then the nozzle is moved away from the electrode 10, the possibility of the first liquid composition P adhering to the nozzle and separating from the electrode 10 is even lower than with the electrode 10 according to the embodiment shown in Figure 14.

[0113] <Embodiment of electrode 10 shown in Figure 16> In the electrode 10 according to the embodiment shown in Figures 7, 14, and 15, the plan view shapes of the first outer peripheral edge 111 of the first region 110, the second inner peripheral edge 121 of the second region 120, the second outer peripheral edge 122 of the second region 120, and the third inner peripheral edge 131 of the third region 130 are all circular. Also, in the electrode 10 according to the embodiment shown in Figures 14 and 15, the plan view shapes of the outer peripheral edge 113 of the central region 112 and the inner peripheral edge 114 of the surrounding region 115 of the first region 110 are all circular. However, these are not limited to circles and may be other shapes such as polygons (triangles, quadrilaterals, hexagons, etc.).

[0114] For example, the electrode 10 according to the embodiment shown in Figure 16 is an example in which the plan view shapes of the first outer peripheral edge 111 of the first region 110, the second inner peripheral edge 121 of the second region 120, the second outer peripheral edge 122 of the second region 120, and the third inner peripheral edge 131 of the third region 130 are all rectangular. In the electrode 10 according to the embodiment shown in Figure 16, the central region 112 of the first region 110 outer edge portion 113 and the inner peripheral edge 11 of the surrounding region 115 4 flatThe surface view shape is circular, but it is not limited to this, and other shapes such as polygons may also be used. Other features of the electrode 10 according to the embodiment shown in Figure 16 are the same as those of the electrode 10 according to the embodiment shown in Figure 14, so their description is omitted.

[0115] <Embodiment of electrode 10 shown in Figures 17 and 18> Further embodiments of the electrode 10 will be described with reference to Figures 17 and 18. Figure 18 is a cross-sectional view along the line E-E' in Figure 17. Figure 17 is an enlarged view of the region of the electrode 10 according to this embodiment that corresponds to region X in the electrode 10 shown in Figure 2. The electrode 10 shown in Figures 17 and 18 according to this embodiment is When placed on an insulating substrate 20, the surface portion 11 is located on the opposite side of the substrate 20, A first region 110 is formed on the surface portion 11, including a first outer peripheral edge portion 111, and at least a portion of it has a first surface free energy, A second region 120 is formed on the surface portion 11, including a second inner peripheral edge portion 121 that surrounds the first region 110 and is in contact with the first outer peripheral edge portion 111 of the first region 110, and a second outer peripheral edge portion 122 that is located outside the second inner peripheral edge portion 121, and having a second surface free energy greater than the first surface free energy, A third region 130 formed on the surface portion 11, which includes a third inner peripheral edge portion 131 that surrounds the second region 120 and is in contact with the second outer peripheral edge portion 122 of the second region 120, and a third outer peripheral edge portion 132 that is located outside the third inner peripheral edge portion 131, and having a third surface free energy smaller than the second surface free energy, A fourth region 140 is formed on the surface portion 11, and includes a fourth inner peripheral edge portion 141 that surrounds the third region 130 and is in contact with the third outer peripheral edge portion 132 of the third region 130, and a fourth outer peripheral edge portion 142 that is located outside the fourth inner peripheral edge portion 141, and has a fourth surface free energy greater than the third surface free energy, It is equipped with.

[0116] The features of the first region 110 and the second region 120 in this embodiment shown in Figures 17 and 18 are the same as those described with respect to the electrode 10 in other embodiments, and therefore will not be described further. In this embodiment shown in Figures 17 and 18, the first region 110 includes a central region 112 having a surface free energy greater than the first surface free energy and a surrounding region 115 having the first surface free energy, similar to the embodiment shown in Figure 14.

[0117] The third surface free energy of the third region 130 only needs to be relatively smaller than the second surface free energy of the second region 120, and may be the same as or different from the first surface free energy of the surrounding region 115 of the first region 110. Preferably, the third surface free energy of the third region 130 is the same as the first surface free energy of the surrounding region 115 of the first region 110. The difference between the third surface free energy of the third region 130 and the second surface free energy, and the preferred range of the third surface free energy are as described in the <Surface Free Energy> section.

[0118] The fourth surface free energy of the fourth region 140 only needs to be relatively larger than the third surface free energy of the third region 130, and may be the same as or different from the second surface free energy of the second region 120. The difference between the fourth surface free energy and the third surface free energy, and specific examples of the value of the fourth surface free energy are as described in the <Surface Free Energy> column.

[0119] By using an electrode 10 equipped with such a surface portion 11, a first region 110, a second region 120, a third region 130, and a fourth region 140, it is possible to accurately form the reagent layer 30 and the protective film 40. This mechanism will be explained with reference to Figures 19 to 22.

[0120] As shown in Figure 19, a first liquid composition P containing a reagent involved in the oxidation-reduction reaction in a first solvent is applied to the first region 110 and the second region 120 of the electrode 10, and then dried to form a reagent layer 30 including an outer peripheral edge 31 located on the second outer peripheral edge 122 of the second region 120, as shown in Figure 20. This step is the same as the step described with reference to Figures 9 and 10 for forming the reagent layer 30 on the electrode 10 according to the embodiment shown in Figures 7 and 8, and therefore no further explanation is given. According to the electrode 10 of this embodiment shown in Figures 17 and 18, it is possible to accurately form a reagent layer 30 of the designed dimensions on the first region 110 and the second region 120 of the surface portion 11. The contact area between the reagent layer 30 and the electrode 10 is defined by the first region 110 and the second region 120 of the electrode 10.

[0121] The electrode 10 according to this embodiment, shown in Figures 17 and 18, includes a third region 130 having a third surface free energy, which has lower wettability with the first liquid composition P compared to the second region 120 having a second surface free energy. Therefore, as shown in Figure 19, the outward spreading of the first liquid composition P applied to the first region 110 and the second region 120 is prevented by the third inner peripheral edge 131 of the third region 130, and the outer periphery is defined by the second outer peripheral edge 122 of the second region 120.

[0122] Next, as shown in Figure 21, the second liquid composition Q, which contains a protective film component in the second solvent, is applied to the first region 110, second region 120, third region 130, and fourth region 140 of the electrode 10 so as to cover the reagent layer 30. Examples of the second solvent and protective film component of the second liquid composition Q are as previously described. The applied second liquid composition Q forms droplets whose outer periphery is defined by the fourth outer edge 142 of the fourth region 140.

[0123] Next, the applied second liquid composition Q is dried to form a protective film 40, as shown in Figure 22. The formed protective film 40 is positioned on the first region 110, second region 120, third region 130, and fourth region 140 of the electrode 10 so as to cover the reagent layer 30, and includes an outer edge portion 41 located on the fourth outer edge portion 142 of the fourth region 140. The area of ​​the protective film 40 is defined by the fourth outer edge portion 142 of the fourth region 140. In this way, the outer shape and area of ​​the protective film 40 can be adjusted by adjusting the outer shape and area of ​​the first region 110, second region 120, third region 130, and fourth region 140. On the other hand, the thickness of the protective film 40 can be adjusted by adjusting the concentration of the protective film component in the second liquid composition Q and the amount of the second liquid composition Q applied. According to the electrode 10 of this embodiment, it is possible to accurately form protective films of the designed dimensions on the first region 110, the second region 120, the third region 130, and the fourth region 140.

[0124] The electrode 10 according to this embodiment, shown in Figures 17 and 18, further comprises a fifth region 150 formed on the surface portion 11, which includes a fifth inner peripheral portion 151 surrounding the fourth region 140 and in contact with the fourth outer peripheral portion 142 of the fourth region 140, and having a fifth surface free energy smaller than the fourth surface free energy. The second liquid composition Q has lower wettability in the fifth region 150 having a fifth surface free energy compared to the fourth region 140 having a fourth surface free energy. Therefore, the outward spreading of the second liquid composition Q, which is applied to cover the reagent layer 30 on the first region 110, second region 120, third region 130, and fourth region 140 of the electrode 10, is prevented by the fifth inner peripheral portion 151 of the fifth region 150, thus further facilitating the realization of the above-mentioned effect in which the outer circumference of the droplet is defined by the fourth outer peripheral portion 142 of the fourth region 140. The difference between the fourth surface free energy and the fifth surface free energy, and specific examples of the value of the fifth surface free energy, are as described in the <Surface Free Energy> column. In an embodiment in which the surface portion 11 of an electrode 10 having a uniform surface free energy is partially treated to increase the surface free energy, thereby forming a second region 120 having a second surface free energy and a fourth region 140 having a fourth surface free energy, the first region 110, the third region 130, and the fifth region 150 have the same surface free energy.

[0125] <Embodiment of electrode 10 shown in Figures 23 and 24> In the electrode 10 according to the embodiment shown in Figures 7, 8, 14, 15, 16, 17, and 18, the second outer peripheral edge 122 of the second region 120 is defined by the third inner peripheral edge 131 of the third region 130. However, the embodiment is not limited to this, and as in the electrode 10 according to the embodiment shown in Figures 23 and 24, the second outer peripheral edge 122 of the second region 120 may be defined by the insulating layer 50. Figure 23 is an enlarged view of the region of the electrode 10 according to this embodiment that corresponds to region X in the electrode 10 shown in Figure 2. Figure 24 is a cross-sectional view along the line F-F' in Figure 23.

[0126] The electrode 10 according to this embodiment, shown in Figures 23 and 24, comprises a surface portion 11, a first region 110, a second region 120, and an insulating layer 50, at least a portion of which is disposed on the surface portion 11. The insulating layer 50 has openings 52 that penetrate in the thickness direction and are formed on the first region 110 and the second region 120. The openings 52 of the insulating layer 50 include an inner peripheral edge portion 55 that defines the second outer peripheral edge portion 122 of the second region 120 in a plan view. The electrode 10 according to this embodiment, shown in Figures 23 and 24, having this configuration, provides the following effects. That is, when a first liquid composition containing a reagent involved in the oxidation-reduction reaction in a first solvent is applied to the recess surrounded by the openings 52 of the insulating layer 50 with the first region 110 and the second region 120 of the electrode 10 as its bottom surface, the outward spreading of the first liquid composition is prevented by the inner peripheral edge portion 55 of the insulating layer 50, and it is applied only on the first region 110 and the second region 120. The reagent layer 30 formed by drying the thus coated first liquid composition includes an outer peripheral edge 31 located on the second outer peripheral edge 122 of the second region 120 defined by the inner peripheral edge 55 of the insulating layer 50, and is positioned only on the first region 110 and the second region 120 (see Figure 25). Therefore, according to the electrode 10 of this embodiment shown in Figures 23 and 24, it is possible to form the reagent layer 30 of the designed dimensions on the first region 110 and the second region 120 with even greater precision. Specific examples of the materials constituting the insulating layer 50 are as described in the <Materials> section above. The insulating layer 50 preferably has a water-repellent surface, and more preferably has a water-repellent surface containing a fluororesin.

[0127] The electrode 10 according to this embodiment, shown in Figures 23 and 24, can be manufactured by laminating an insulating layer 50 on the surface portion 11 of the electrode 10, which has a surface portion 11 on which a first region 110 and a second region 120 are formed, with an opening 52 in which the inner peripheral edge 55 is located outside the second inner peripheral edge 121 of the second region 120 and on the second region 120. In this case, the inner peripheral edge 55 of the opening 52 of the insulating layer 50 defines the second outer peripheral edge 122 of the second region 120 within the opening 52. The features of other components (e.g., the first region 110 and the second region 120) in the electrode 10 according to this embodiment shown in Figures 23 and 24 are the same as the features of each component in the electrode 10 according to the embodiments shown in Figures 7, 8, 14, 15, 16, 17 and 18.

[0128] In this embodiment, as shown in Figures 23 and 24, a reagent layer 30 can be placed on the first region 110 and the second region 120 of the electrode 10, and a protective film 40 can be placed on top of it (see Figure 25). The protective film 40 can be formed by applying a second liquid composition containing a protective film component in a second solvent to a recess surrounded by the opening 52 of the insulating layer 50, where the reagent layer 30 is placed and the first region 110 and the second region 120 of the electrode 10 are the bottom surfaces, and then drying it. In this case as well, the outward spreading of the applied second liquid composition is prevented by the inner peripheral edge 55 of the insulating layer 50, so after drying, the protective film 40 is placed covering only the first region 110 and the second region 120 with the reagent layer 30.

[0129] <Embodiment of electrode 10 shown in Figures 30 and 31> Another embodiment of the electrode 10 will be described with reference to Figures 30 and 31. Figure 30 is an enlarged view of the region of the electrode 10 according to this embodiment that corresponds to region X in the electrode 10 shown in Figure 2. Figure 31 is a cross-sectional view along the line G-G' in the figure. This embodiment is a modified example of the embodiment of the electrode 10 shown in Figures 17 and 18.

[0130] The electrode 10 according to this embodiment, shown in Figures 30 and 31, When placed on an insulating substrate 20, the surface portion 11 is located on the opposite side of the substrate 20, A first region 110 is formed on the surface portion 11, including a first outer peripheral edge portion 111, and having a first surface free energy. A second region 120 is formed on the surface portion 11, including a second inner peripheral edge portion 121 that surrounds the first region 110 and is in contact with the first outer peripheral edge portion 111 of the first region 110, and a second outer peripheral edge portion 122 that is located outside the second inner peripheral edge portion 121, and having a second surface free energy greater than the first surface free energy, A third region 130 formed on the surface portion 11, which includes a third inner peripheral edge portion 131 that surrounds the second region 120 and is in contact with the second outer peripheral edge portion 122 of the second region 120, and a third outer peripheral edge portion 132 that is located outside the third inner peripheral edge portion 131, and having a third surface free energy smaller than the second surface free energy, A fourth region 140 is formed on the surface portion 11, and includes a fourth inner peripheral edge portion 141 that surrounds the third region 130 and is in contact with the third outer peripheral edge portion 132 of the third region 130, and a fourth outer peripheral edge portion 142 that is located outside the fourth inner peripheral edge portion 141, and has a fourth surface free energy greater than the third surface free energy, An insulating layer 50 is formed on the first region 110, second region 120, third region 130, and fourth region 140, at least a portion of which is located on the surface portion 11, and includes an opening 52 that penetrates in the thickness direction and has an inner peripheral edge 55 that contacts the fourth outer peripheral edge 142 of the fourth region 140 in a plan view from a direction perpendicular to the surface portion 11, It is equipped with.

[0131] The features of the surface portion 11, the first region 110, the second region 120, the third region 130, the fourth region 140, and the insulating layer 50 in this embodiment shown in Figures 30 and 31, other than those described below, are the same as those described for the electrode 10 in other embodiments, and therefore will not be described further. Note that the first region 110 in this embodiment shown in Figures 30 and 31 has a first surface free energy as a whole, similar to the embodiment shown in Figure 7.

[0132] Figure 32 shows a cross-sectional view of a sensor 1 equipped with a working electrode 2 including the electrode 10 shown in Figures 30 and 31 according to this embodiment. The working electrode 2 (sensor 1) shown in Figure 32 comprises a substrate 20, the electrode 10 shown in Figures 30 and 31 according to this embodiment disposed on the substrate 20, a reagent layer 30 disposed on a first region 110 and a second region 120 within an opening 52 of an insulating layer 50, and a protective film 40 disposed on the first region 110, the second region 120, the third region 130 and the fourth region 140 within an opening 52 of an insulating layer 50 so as to cover the reagent layer 30.

[0133] In the working electrode 2 (sensor 1) shown in Figure 32, the reagent layer 30 includes an outer peripheral edge 31 located on the second outer peripheral edge 122 of the second region 120, and a reagent involved in the redox reaction. The reagent layer 30 can be formed by the method described with reference to Figures 9 and 19.

[0134] In the working electrode 2 (sensor 1) shown in Figure 32, the protective film 40 is located on the fourth outer peripheral edge 142 of the fourth region 140 and includes an outer peripheral edge 41 defined by the inner peripheral edge 55 of the insulating layer 50. The protective film 40 is formed by coating the reagent layer 30 with a second liquid composition containing the protective film component in a second solvent within the opening 52 of the insulating layer 50, on the first region 110, the second region 120, the third region 130, and the fourth region 140, and then drying it, as described with reference to Figures 11 and 21. Using the electrode 10 shown in Figures 30 and 31 is advantageous in the following respects.

[0135] Because the outward spreading of the applied second liquid composition is prevented by the inner peripheral edge 55 of the insulating layer 50, the peripheral edge 41 of the dried protective film 40 can be located on the fourth peripheral edge 142 of the fourth region 140.

[0136] On the other hand, when an insulating layer 50 having an opening 52 is formed on the surface portion 11 of the electrode 10 using a printing method such as screen printing, the inner peripheral edge 55 of the opening 52 may have fine irregularities when viewed in plan from a direction perpendicular to the surface portion 11 due to processing accuracy constraints. If the electrode 10 equipped with such an insulating layer 50 is such that, as shown in Figure 11, the outer peripheral edge of the bottom surface of the recess formed by the opening 52 of the insulating layer 50 and the surface portion 11 of the electrode 10 is a third region 130 having a third surface free energy with low wettability to the second liquid composition, the following problem may occur. That is, the applied second liquid composition cannot adhere to the inner peripheral edge 55 of the opening 52 of the insulating layer 50 and does not spread and wet the entire opening 52 of the insulating layer 50, so the area of ​​the protective film 40 formed after drying is smaller than designed, and the protective film 40 may be prone to peeling. Furthermore, within the opening 52 of the insulating layer 50, the outer peripheral edge 41 of the dried protective film 40 may not adhere sufficiently to the third region 130 of the surface portion 11 of the electrode 10, which can lead to the problem of the protective film 40 being easily peeled off. In the electrode 10 shown in Figures 30 and 31, the outer peripheral edge of the bottom surface of the recess formed by the opening 52 of the insulating layer 50 and the surface portion 11 of the electrode 10 is a fourth region 140 having a fourth surface free energy that is highly wettable to the second liquid composition. Therefore, even if the inner peripheral edge 55 of the opening 52 of the insulating layer 50 has fine irregularities, the applied second liquid composition can wet and spread to the fourth outer peripheral edge 142 of the fourth region 140, and adhere closely to the inner peripheral edge 55 of the opening 52 of the insulating layer 50 that is in contact with the fourth outer peripheral edge 142 in a plan view. As a result, the protective film 40 after drying is formed over the entire opening 52 of the insulating layer 50 with the area as designed, and the outer peripheral edge 41 of the protective film 40 can adhere closely to the fourth outer peripheral edge 142 of the fourth region 140, making it less likely to peel off, which is preferable.

[0137] Next, the manufacturing method of the electrode 10 according to this embodiment, as shown in Figures 30 and 31, will be described with reference to Figures 33 to 36.

[0138] The method for manufacturing the electrode 10 according to this embodiment includes preparing an untreated electrode 10A as shown in Figure 33. Here, the untreated electrode 10A comprises an untreated surface portion 11A having a first surface free energy and having an untreated region 500 in part for forming a first region 110, a second region 120, a third region 130, and a fourth region 140, and an insulating layer 50 having an opening 52 formed on the untreated region 500 and penetrating in the thickness direction, at least a portion of which is disposed on the untreated surface portion 11A. Here, the materials constituting the untreated electrode 10A and the insulating layer 50 can be selected from the same range as the materials constituting the electrode 10 and insulating layer 50 in the electrode 10 and sensor 1 of each embodiment disclosed herein.

[0139] The manufacturing method of the electrode 10 according to this embodiment further includes irradiating a laser beam onto an annular fourth untreated region 540 located on the outer periphery of the untreated region 500 of the untreated surface portion 11A of the untreated electrode 10A, which is adjacent to the inner peripheral edge 55 of the opening 52 of the insulating layer 50 in a plan view from a direction perpendicular to the untreated surface portion 11A, and an annular second untreated region 520 located further inward from the fourth untreated region 540, thereby converting the fourth untreated region 540 into the fourth region 140 and the second untreated region 520 into the second region 120.

[0140] Figure 34 schematically shows an enlarged view of a portion of the untreated electrode 10A shown in Figure 33, including the boundary between the untreated region 500 of the untreated surface portion 11A and the insulating layer 50 surrounding the opening 52 in a plan view. In the illustrated example, the fine irregularities of the inner peripheral edge 55 of the opening 52 in the insulating layer 50 are emphasized. Of the untreated region 500, the portion contained within the second untreated region 520 is the first untreated region 510, and the portion between the second untreated region 520 and the fourth untreated region 540 is the third untreated region 530. In other words, the untreated region 500 consists of a first untreated region 510, a ring-shaped second untreated region 520 surrounding the first untreated region 510, a ring-shaped third untreated region 530 surrounding the second untreated region 520, and a ring-shaped fourth untreated region 540 surrounding the third untreated region 530, and the entire untreated region 500 has a first surface free energy.

[0141] Figure 35 schematically shows a portion of the electrode 10 obtained by irradiating it with laser light, corresponding to a part of the untreated electrode 10A shown in Figure 34, to convert the fourth untreated region 540 into the fourth region 140 and the second untreated region 520 into the second region 120. Here, the laser light irradiation is a process in which the surface free energy of the second untreated region 520 and the fourth untreated region 540 is increased by, for example, scanning the laser light, converting them into the second region 120 having a second surface free energy and the fourth region 140 having a fourth surface free energy, respectively. Preferably, the first untreated region 510 and the third untreated region 530 of the untreated region 500 in the untreated electrode 10A are not irradiated with laser light and become the first region 110 and the third region 130 of the electrode 10 having a first surface free energy. In this case, the third region 130 has a third surface free energy that is the same as the first surface free energy. The preferred mode of the irradiated laser light is as described above.

[0142] When irradiating the fourth untreated region 540 of the untreated region 500 of the untreated surface portion 11A shown in Figure 34 with laser light, it is preferable to irradiate not only the fourth untreated region 540 but also the surrounding region 58 of the insulating layer 50 that surrounds the opening 52, which is adjacent to the outside of the fourth untreated region 540 in a plan view from a direction perpendicular to the untreated surface portion 11A. According to this embodiment, as shown in the figure, even if the inner peripheral edge 55 of the opening 52 of the insulating layer 50 has fine irregularities that are intricately arranged inward, the laser light can be irradiated up to the inner peripheral edge 55 of the fourth untreated region 540 of the untreated region 500, converting it into the fourth region 140. According to the electrode 10 manufactured in this manner, as shown in the embodiments of Figures 30 and 31, the second liquid composition applied to the opening 52 of the insulating layer 50 can wet and spread to the fourth outer peripheral edge 142 of the fourth region 140, and the protective film 40 obtained after drying can have the area as designed and is less prone to peeling, which is a particularly good way to achieve the above-mentioned effects.

[0143] In a more preferred embodiment of the untreated surface portion 11A shown in Figure 34, in addition to the fourth untreated region 540, the laser beam is also irradiated to the aperture peripheral region 58 of the insulating layer 50. This further includes irradiating the aperture peripheral region 58 of the insulating layer 50 with the laser beam to destroy the insulating layer 50 in the aperture peripheral region 58, and converting the portion of the untreated surface portion 11A exposed by the destruction into the fourth region 140. Figure 36 schematically shows a portion of the electrode 10 manufactured by this preferred embodiment. The fourth region 140 of the electrode 10 manufactured by this preferred embodiment is a region in which the surface free energy of the untreated surface portion 11A, consisting of the fourth untreated region 540 of the untreated region 500 and the portion of the aperture peripheral region 58 of the insulating layer 50 that has been destroyed and exposed, has been increased to the fourth surface free energy by laser irradiation. In this preferred embodiment, since the fourth outer peripheral edge 142 of the fourth region 140 defining the outer periphery of the protective film 40 and the inner peripheral edge 55 of the opening 52 of the insulating layer 50 are formed by laser irradiation, it is possible to define the outer periphery of the protective film 40 with higher precision compared to the case where the insulating layer 50 having the opening 52 is formed by printing. Furthermore, in this preferred embodiment, since the second outer peripheral edge 122 of the second region 120 defining the outer periphery of the reagent layer 30 and the fourth outer peripheral edge 142 of the fourth region 140 defining the outer periphery of the protective film 40 and the inner peripheral edge 55 of the opening 52 of the insulating layer 50 are both formed by laser irradiation, it is possible to manufacture an electrode 10 in which the reagent layer 30 and the protective film 40 can be formed more accurately and coaxially. [Examples]

[0144] In the following experiments, operations where the temperature is not specifically mentioned were performed at room temperature (21°C ± 3°C). <Experiment 1> As shown in Figure 7, the annular portion of the surface 11 of the electrode 10 was laser-processed to increase the surface free energy and form a second region 120. The interior of the second region 120 was designated as the first region 110, and the exterior as the third region 130. A reagent layer 30 was formed on the first region 110 and the second region 120 of the obtained electrode 10 to manufacture a sensor 1 equipped with a working electrode 2.

[0145] (substrate) As the insulating substrate 20, a 188 μm thick substrate made of polyethylene terephthalate with the shape shown in Figure 1, etc., was used.

[0146] (electrode) By applying carbon paste to the first surface 21 of an insulating substrate 20 and heating it at 140°C for 1 hour, two electrodes 10, 10, a reference electrode conductive layer 301, a counter electrode 4, and wiring 5 electrically connected to each of them were formed from a 5 μm thick carbon conductive layer, as shown in Figure 1.

[0147] (Laser processing) A second region 120 was formed by laser processing on the annular portion of the surface 11 of the electrode 10 placed on the substrate 20 to increase the surface free energy. As shown in Figure 7, annular portions with a diameter M of 1.2 mm and a width N of 0.1 mm, 0.2 mm, or 0.3 mm were laser processed under the following conditions to form the second region 120 of the electrode 10 in the example. As a comparative example, a circular region with a diameter of 1.2 mm on the surface 11 of the electrode 10 placed on the substrate 20 was laser processed under the same conditions.

[0148] [Table 1]

[0149] The surface free energy (dispersion component, polar component) of the surface portion 11 of the electrode 10 was determined before laser processing and after a predetermined time had elapsed after laser processing. The surface free energy was calculated using a system of equations (1), (2), and (3) above, after measuring the contact angle with respect to water and diiodomethane (1 μL drop, measured 2 seconds after dropping) using a contact angle meter at 20°C and 40% relative humidity.

[0150] The table below shows the surface free energy (dispersion component, polar component) at each elapsed time after laser processing for the second region 120 of the electrode 10 in the example and the circular region of the electrode in the comparative example, which were formed by laser processing. The surface free energy at elapsed time 0 minutes is the surface free energy of the surface portion 11 of the electrode 10 before laser processing and is considered to be the surface free energy of the first region 110 and the third region 130.

[0151] [Table 2]

[0152] (First liquid composition) As a first liquid composition for forming the reagent layer, an aqueous solution was prepared containing a carbon black dispersion, hydroxypropyl cellulose, a polymer-bound mediator, lactate oxidase, polyimidazole, poly-L-lysine, and a crosslinking agent in water.

[0153] (Formation of the reagent layer) Twenty-four hours after laser processing, 0.65 mg of the first liquid composition was dropped onto the center of the first region 110 of the electrode 10 of the embodiment, which has a first region 110 and laser-processed annular second regions 120 of various widths surrounding it, to form a droplet. After drying, a reagent layer 30 containing lactate oxidase and a mediator was formed to manufacture a sensor 1 equipped with a working electrode 2.

[0154] On the other hand, 24 hours after laser processing, 0.65 mg of the first liquid composition was dropped onto the center of the circular region of the electrode of the comparative example having a laser-processed circular region to form a droplet, which was then dried to form a reagent layer containing lactate oxidase and a mediator.

[0155] Photographs of the reagent layers formed on each electrode are shown in Figure 27. In all of the electrodes 10 of the examples, the reagent layer 30 was formed only on the first region 110 and the second region 120, and the outer peripheral edge 31 of the reagent layer 30 was located on the second outer peripheral edge 122 of the second region 120.

[0156] On the other hand, in the comparative example, in 8 out of 12 samples on the electrode, the first liquid composition applied to the circular region overflowed from the circular region, resulting in an irregularly shaped reagent layer after drying.

[0157] <Experiment 2> Using the same materials as in Experiment 1, laser processing was performed using the same procedure to form a second annular region 120 with a diameter M of 1.2 mm and a width N of 0.3 mm on the surface 11 of the electrode 10, as shown in Figure 7. The area inside this region was designated as the first region 110, and the area outside of it as the third region 130.

[0158] The nozzle was brought close to the center of the first region 110 of the electrode 10 to a distance of 0.5 mm, and 0.65 mg of the same first liquid composition as in Experiment 1 was dropped from the nozzle. The nozzle was then moved away and allowed to dry, forming a reagent layer 30 containing lactate oxidase and a mediator.

[0159] When the reagent layer 30 was formed 10 times, in 5 of those attempts, the first liquid composition that adhered to the nozzle separated from the electrode 10 when the nozzle was moved away, making it impossible to coat.

[0160] <Experiment 3> Using the same materials as in Experiment 1 and following the same procedure, an electrode 10 was created that includes a first region 110 with the shape shown in Figure 14, comprising a central region 112 (laser-processed portion) and a peripheral region 115 (unprocessed portion), a ring-shaped second region 120 (laser-processed portion), and a third region 130 outside the second region 120. As shown in Figure 14, the diameter W of the central region 112 was 0.25 mm, the diameter M of the second region 120 was 1.2 mm, and the width N of the second region 120 was 0.25 mm.

[0161] Similar to Experiment 2, the nozzle was brought close to the central region 112 of the first region 110 of the electrode 10 to a distance of 0.5 mm, 0.65 mg of the same first liquid composition as in Experiments 1 and 2 was dropped from the nozzle, and then the nozzle was moved away and dried to form a reagent layer 30 containing lactate oxidase and mediator.

[0162] When the first liquid composition was applied and dried approximately 200 times, the first liquid composition was applied normally each time. The reagent layer 30 obtained by drying the applied first liquid composition was formed only on the first region 110 and the second region 120, and the outer edge 31 of the reagent layer 30 was precisely located on the second outer edge 122 of the second region 120. A photograph of a part of the formed reagent layer 30 is shown in Figure 28.

[0163] <Experiment 4> Using the same materials as in Experiment 1, laser processing was performed under the same conditions. Similar to Experiment 1, a second annular region 120 with a diameter M of 1.2 mm and a width N of 0.1 mm or 0.3 mm, as shown in Figure 7, was formed on the surface 11 of the electrode 10 placed on the first surface 21 of the insulating substrate 20. The area inside this region was designated as the first region 110, and the area outside it as the third region 130. As a comparative example, similar to Experiment 1, laser processing was performed under the same conditions on a circular region with a diameter of 1.2 mm on the surface 11 of the electrode 10 placed on the substrate 20.

[0164] As a first liquid composition for forming the reagent layer, a solution containing a carbon black dispersion, a polymer-bound mediator, lactate oxidase, polyimidazole, and ε-poly-L-lysine was prepared in ultrapure water (Milli-Q® water).

[0165] Twenty-four hours after laser processing, the electrode 10 of the example, which has a first region 110 and laser-processed annular second regions 120 of varying widths surrounding it, was subjected to a drop of the first liquid composition in an amount described later to form a droplet, which was then dried to form a reagent layer 30 for lactic acid detection. On the other hand, 24 hours after laser processing, the electrode of the comparative example, which has a laser-processed circular region, was subjected to a drop of the first liquid composition in an amount described later to form a droplet, which was then dried to form a reagent layer for lactic acid detection.

[0166] In this test, the amount of the first liquid composition used to dropwise form the reagent layer described above was gradually increased from 0.40 g to 0.05 g increments. The maximum amount of the first liquid composition that could be loaded without overflowing to form a perfectly circular reagent layer on the first region 110 and the second region 120 of the electrode 10 of each example, or on the circular region of the electrode of the comparative example, was determined (the maximum amount that could be loaded in 10 tests to form a perfectly circular reagent layer without overflowing). As a result, it was confirmed that the maximum amount of the first liquid composition was 0.75 mg for the electrode 10 of the example having an annular second region 120 with a diameter M of 1.2 mm and a width N of 0.1 mm as shown in Figure 7, 0.70 mg for the electrode 10 of the example having an annular second region 120 with a diameter M of 1.2 mm and a width N of 0.3 mm, and 0.60 mg for the electrode of the comparative example having a circular region with a diameter of 1.2 mm. In other words, it was confirmed that a larger amount of the first liquid composition can be supported by forming a first region 110 in the center having a first surface free energy with low wettability to the first liquid composition, and forming a second region 120 around it having a second surface free energy with high wettability to the first liquid composition, and that the smaller the width N of the second region 120, the larger the amount of the first liquid composition can be supported.

[0167] <Experiment 5> A sensor 1 with the configuration shown in Figure 5 was manufactured. The materials and manufacturing method used for sensor 1 with the configuration shown in Figure 5 are outlined below. Of the two working electrodes 2, one was used as the working electrode for lactate detection, and the other as the working electrode for glucose detection. Since lactate was measured in the measurement test described later, only the manufacturing method for the working electrode for lactate detection will be described below.

[0168] (substrate) As the insulating substrate 20, a 188 μm thick substrate made of polyethylene terephthalate with the shape shown in Figure 1, etc., was used.

[0169] (Conductive layer) By applying carbon paste to the first surface 21 of an insulating substrate 20 and heating it at 140°C for 1 hour, an electrode 10, a reference electrode conductive layer 301, a counter electrode 4, and wiring 5 electrically connected to each of them, as shown in Figure 1, were formed from a carbon conductive layer with a thickness of 5 μm.

[0170] (Laser processing) Under the conditions described in Experiment 1, a laser process was applied to the annular portion of the surface 11 of the electrode 10 placed on the substrate 20, with a diameter M of 1.4 mm and a width N of 0.3 mm as shown in Figure 7, to increase the surface free energy and form a second region 120. The portion of the surface 11 of the electrode 10 inside the second region 120 is the first region 110, and the portion outside the second region 120 is the third region 130.

[0171] (Insulating layer) Next, an insulating layer 50 made of fluororesin was laminated onto the first surface 21 of the substrate 20 on which the carbon conductive layer was placed, as shown in Figure 3.

[0172] The openings 52 formed on the first region 110, second region 120, and third region 130 of the insulating layer 50 were circular with a diameter of 2.0 mm. The reference electrode opening 53 was circular with a diameter of 1.0 mm, and the counter electrode opening 54 was rectangular with dimensions of 2.7 mm × 2.65 mm.

[0173] (Reagent layer) 24 hours after laser processing, 0.40 mg, 0.45 mg, 0.50 mg, 0.55 mg, and 0.60 mg of the first liquid composition containing lactate oxidase, as described in Experiment 4, were dropped onto the center of the first region 110 within the opening 52 of the insulating layer 50 to form droplets on the first and second regions, and then dried to form a reagent layer 30 for lactate detection (see Figure 4).

[0174] (protective film) To a Nafion® dispersion (manufactured by Sigma-Aldrich), ethanol (manufactured by Fujifilm Wako Pure Chemical Industries) and an aqueous sodium hydroxide solution (manufactured by Fujifilm Wako Pure Chemical Industries) were added to adjust the pH of the dispersion (neutralization of cation exchange groups). The precipitate was dissolved in a vortex mixer and the solution was adjusted to 9 wt% to prepare the second liquid composition A.

[0175] The following reagents were mixed with ethanol to the final concentrations shown below and reacted for approximately 1 hour to prepare the second liquid composition B. P4VP-tBuMA (Mn: 74,000 for poly-4-vinylpyridine, Mn: 87,000 for poly-tert-butyl methacrylate, Mw / Mn: 1.16, manufactured by NARD), final concentration 3.55 wt% • Random copolymer of tripropylene glycol methyl ether methacrylate-styrene-4-vinylpyridine (NARD), final concentration 4.45 wt% • PEGDGE (poly(ethylene glycol) diglycidyl ether, Mn: ~1,000, manufactured by Sigma-Aldrich), 0.9 wt%

[0176] After the reagent layer 30 was formed, 0.6 mg of the second liquid composition A was dropped into the opening 52 of the insulating layer 50 to form a droplet, which was then dried to form the first layer of the protective film 40. Next, 0.6 mg of the second liquid composition B was dropped into the opening 52 to form a droplet, which was then dried to form the second layer of the protective film 40, thereby creating a two-layer protective film 40. In this way, the working electrode 2 with the cross-sectional structure shown in Figure 11 (although not shown, the protective film 40 has a two-layer structure) was completed.

[0177] (Reference pole) A silver / silver chloride paste was applied to the reference electrode conductive layer 301 within the reference electrode opening 53 of the insulating layer 50, and heated at 140°C for 1 hour to form a silver / silver chloride layer 302. Subsequently, a reference electrode protective film 303 was placed on the silver / silver chloride layer 302 to form a reference electrode 3 with the cross-sectional structure shown in Figure 12.

[0178] (Storage under high-temperature conditions) Sensor 1, manufactured as described above, was stored at 60°C for two weeks after manufacturing and then used to measure lactic acid concentration.

[0179] (Continuous measurement of lactate concentration) culture medium for measurement DMEM, no glucose(Gibco 11966025) Penicillin-Streptomycin-Amphotericin B suspension (x100) (Antibiotic-Antifungal solution) (Fujifilm Wako Pure Chemical Industries 161-23181) Sodium Pyruvate (100mM) (Gibco 11360070) Using the reagents described above, DMEM medium containing a penicillin-streptomycin-amphotericin B suspension at a final concentration of 1% (v / v) and sodium pyruvate at a final concentration of 1 mM was prepared.

[0180] The measurement media were prepared using DMEM medium as shown below. Medium 1: DMEM medium adjusted to a final lactate concentration of 6 mM. Medium 2: DMEM medium adjusted to a final lactate concentration of 12 mM. Medium 3: DMEM medium adjusted to a final concentration of approximately 9% (v / v) of FBS (Fetal Bovine Serum Gibco 16140071) and a final lactate concentration of 16 mM. Blank medium: DMEM medium adjusted to a final lactate concentration of 10 mM.

[0181] A voltage of 100mV was applied to the working electrode 2, which was immersed in the measurement culture medium, relative to the reference electrode 3 (Ag / AgCl). The current value between the working electrode 2 and the counter electrode 4 was measured continuously for approximately 12 days (approximately 288 hours). The measurements were performed in a CO2 incubator with CO2 5% and a temperature of 37°C.

[0182] Measurement test (N=3): The above measurements were performed using media 1 to 3 as measurement media, replacing them over time in the following order. Medium 1: approx. 24 hours → Medium 2: approx. 24 hours → Medium 3: approx. 72 hours → Medium 1: approx. 9 hours → Medium 2: approx. 15 hours → Medium 3: approx. 72 hours → Medium 3: approx. 72 hours

[0183] Blank test (N=1): The blank culture medium was used as the measurement medium, and the above measurements were performed for approximately 288 hours, replacing it with a new one at the same time as in the measurement test above.

[0184] Figures 29A to 29E show the measurement results of the current values ​​between the working electrode 2 and the counter electrode 4 for lactic acid measurement. Figure 29A shows the current value of sensor 1 with a coating amount of 0.40 mg of the lactate oxidase-containing first liquid composition described in Experiment 4 used to prepare the reagent layer 30, Figure 29B shows the current value of sensor 1 with 0.45 mg, Figure 29C shows the current value of sensor 1 with 0.50 mg, Figure 29D shows the current value of sensor 1 with 0.55 mg, and Figure 29E shows the current value of sensor 1 with 0.60 mg.

[0185] The decay rate of the current value of sensor 1 after 12 days was 37.8% when the amount of lactate oxidase-containing first liquid composition with the composition described in Experiment 4 used to prepare the reagent layer 30 was 0.40 mg (Figure 29A), 29.0% when it was 0.45 mg (Figure 29B), 20.0% when it was 0.50 mg (Figure 29C), 17.0% when it was 0.55 mg (Figure 29D), and 11.0% when it was 0.60 mg (Figure 29E). This result indicates that the larger the amount of reagent loaded in the reagent layer 30, the longer the continuous measurement of the test substance can be performed. It was suggested that sensor 1 equipped with the electrode 10 disclosed herein is suitable for long-term continuous measurement of the test substance because it can load a large amount of reagent into the reagent layer 30.

[0186] <Experiment 6> An electrode 10 with the configuration shown in Figures 30 and 31 was manufactured, and a reagent layer 30 and a protective film 40 were further formed to manufacture the working electrode 2 shown in Figure 32. However, in this experiment 6, unlike the examples shown in Figures 30 to 32, instead of an annular second region 120 containing a circular first region 110, the first region 110 was omitted, and a circular second region 120 having a second surface free energy was formed as a whole, and the reagent layer 30 was placed on the circular second region 120.

[0187] An untreated electrode 10A was formed by applying carbon paste to the first surface 21 of an insulating substrate 20 made of polyethylene terephthalate with a thickness of 188 μm and heating it at 140°C for 1 hour, thereby creating a carbon conductive layer with a thickness of 5 μm.

[0188] Next, an insulating layer 50 made of fluororesin was laminated onto the first surface 21 of the substrate 20 on which the untreated electrode 10A was placed, by screen printing. The thickness of the insulating layer 50 on the untreated electrode 10A was 5 μm. In addition, the opening 52 formed on the untreated region 500 of the untreated surface portion 11A of the untreated electrode 10A in the insulating layer 50 was circular with a diameter (inner diameter) of 2.0 mm.

[0189] In Experiment 6-1, under the conditions described in Experiment 1, laser light was irradiated onto a circular untreated region 500 of the untreated surface portion 11A of the untreated electrode 10A within the opening 52 of the insulating layer 50. Specifically, a second circular untreated region 520 with a diameter of 1.4 mm from the center of the untreated region 500, and an annular fourth untreated region 540 located on the outer circumference of the untreated region 500, 1.75 mm from the center, adjacent to the inner peripheral edge 55 of the opening 52 of the insulating layer 50. This transformed the circular second untreated region 520 into a circular second region 120, and the annular fourth untreated region 540 into an annular fourth region 140. At this time, laser light was also irradiated onto the area 58 surrounding the opening of the insulating layer 50, which is adjacent to the outside of the fourth untreated region 540. The area between the second region 120 and the fourth region 140 after laser light irradiation is the third region 130. Since laser irradiation was performed under the same conditions as in Experiment 1, the surface free energy γs of the untreated region 500 of the untreated surface portion 11A of the untreated electrode 10A and the third region 130 of electrode 10 is 47.82 mN / m (dispersion component γsd is 44.92 mN / m, polar component γsp is 2.90 mN / m). The surface free energy γs of the second region 120 and the fourth region 140 of electrode 10 24 hours after laser irradiation is 60.28 mN / m (dispersion component γsd is 48.48 mN / m, polar component γsp is 11.80 mN / m). A photograph of electrode 10 after laser irradiation in Experiment 6-1 is shown in the upper right of Figure 37.

[0190] In Experiment 6-2, under the conditions described in Experiment 1, laser light was irradiated only to a circular second untreated region 520 with a diameter of 1.4 mm from the center of the circular untreated region 500 of the untreated surface portion 11A of the untreated electrode 10A within the opening 52 of the insulating layer 50, converting it into a circular second region 120. The portion outside the second region 120 within the opening 52 of the insulating layer 50 after laser light irradiation is the third region 130. The surface free energies of the second region 120 and the third region 130 after laser light irradiation are the same as in Experiment 6-1. A photograph of the electrode 10 after laser light irradiation in Experiment 6-2 is shown in the upper left of Figure 37.

[0191] (Reagent layer) 24 hours after laser processing, 0.5 mg of the first liquid composition containing lactate oxidase, with the composition described in Experiment 4, was dropped onto the center of the second region 120 within the opening 52 of the insulating layer 50 of the electrode 10 in Experiment 6-1 or Experiment 6-2 to form a droplet on the second region 120. After drying, the droplet was dried to form a reagent layer 30 for lactate detection (see Figure 32).

[0192] (protective film) In Experiment 6-1 or Experiment 6-2, after the formation of the reagent layer 30, 0.6 mg of the second liquid composition A described in Experiment 5 was dropped into the opening 52 of the insulating layer 50 of the electrode 10 to form a droplet, which was then dried to form the first layer of the protective film 40. Subsequently, 0.6 mg of the second liquid composition B described in Experiment 5 was dropped to form a droplet, which was then dried to form the second layer of the protective film 40, thereby creating a two-layer protective film 40. In this way, the working electrode 2 with the cross-sectional structure shown in Figure 32 (although the protective film 40 has a two-layer structure, it is not shown) was completed. The thickness of the dried protective film 40 on the electrode 10 of Experiment 6-1 or Experiment 6-2 was measured using a white light interferometer based on the difference in height measured before and after the formation of the protective film 40. The thickness measurement results are shown in Figure 38.

[0193] (Shape of protective film) A photograph of the working electrode 2 using electrode 10 from Experiment 6-2 is shown in the lower left of Figure 37. In the working electrode 2 using electrode 10 from Experiment 6-2, the outer diameter of the protective film 40 was 1.88 mm, which was smaller than the design value of the inner diameter of the opening 52 of the insulating layer 50. Furthermore, as shown in Figure 38, the thickness of the protective film 40 in the working electrode 2 using electrode 10 from Experiment 6-2 was approximately 22 μm, which was thicker than when electrode 10 was used in Experiment 6-1, and the standard deviation was confirmed to be about twice as large. These results suggest that the inner peripheral edge 55 of the opening 52 of the insulating layer 50 formed by screen printing has fine irregularities in a plan view, and that in the electrode 10 of Experiment 6-2, the second liquid compositions A and B used to create the protective film 40 applied to the opening 52 of the insulating layer 50 could not adhere sufficiently to the inner peripheral edge 55 of the opening 52 of the insulating layer 50 and the third outer peripheral edge 132 of the third region 130.

[0194] A photograph of the working electrode 2 using electrode 10 from Experiment 6-1 is shown in the lower right of Figure 37. In the working electrode 2 using electrode 10 from Experiment 6-1, the outer diameter of the protective film 40 matched the design value of 2.0 mm for the inner diameter of the opening 52 of the insulating layer 50. Furthermore, as shown in Figure 38, the thickness of the protective film 40 in the working electrode 2 using electrode 10 from Experiment 6-1 was approximately 18 μm, which was thinner and had a smaller standard deviation than when electrode 10 was used in Experiment 6-2. In the electrode 10 of Experiment 6-1, the outer peripheral edge of the bottom of the opening 52 of the insulating layer 50 is a fourth region 140 having a fourth surface free energy, which suggests that the second liquid compositions A and B for creating the protective film 40 were able to spread over the entire opening 52 of the insulating layer 50. Furthermore, a portion of the insulating layer 50 corresponding to the fine irregularities of the inner peripheral edge 55 of the opening 52 was destroyed by laser irradiation, and the exposed untreated surface portion 11A was converted into the fourth region 140. This allowed the second liquid compositions A and B to adhere sufficiently to the inner peripheral edge 55 of the opening 52 of the insulating layer 50, thus enabling the formation of a protective film 40 over the entire opening 52 of the insulating layer 50.

[0195] This specification includes disclosures relating to the following appendices 1 to 20. <Note 1> An electrode placed on an insulating substrate, A surface portion located on the opposite side of the substrate when placed on the substrate, A first region formed on the surface, including a first outer peripheral edge, wherein at least a portion of it has a first surface free energy, A second region is formed on the surface, including a second inner peripheral edge that surrounds the first region and is in contact with the first outer peripheral edge of the first region, and a second outer peripheral edge located outside the second inner peripheral edge, and having a second surface free energy greater than the first surface free energy, A third region is formed on the surface, including a third inner peripheral edge that surrounds the second region and is in contact with the second outer peripheral edge of the second region, and having a third surface free energy smaller than the second surface free energy, Equipped with electrodes.

[0196] <Note 2> The entire first region has the first surface free energy, The electrodes described in Appendix 1.

[0197] <Note 3> The first region is, A central region is located within the first region, including an outer peripheral edge that is located inside the first outer peripheral edge of the first region, and having a surface free energy greater than the first surface free energy, A surrounding region having the first surface free energy, including an inner peripheral edge that surrounds the central region and is in contact with the outer peripheral edge of the central region, and the first outer peripheral edge, including, The electrodes described in Appendix 1.

[0198] <Note 4> The first region is, The region further includes a connecting region having a surface free energy greater than the first surface free energy, extending through the surrounding region from a part of the outer peripheral edge of the central region to a part of the second inner peripheral edge of the second region, which is opposite through the surrounding region. The electrodes described in Appendix 3.

[0199] <Note 5> The third region further includes a third outer peripheral edge located outside the third inner peripheral edge, The surface further comprises a fourth region having a fourth surface free energy greater than the third surface free energy, which includes a fourth inner peripheral edge formed on the surface that surrounds the third region and is in contact with the third outer peripheral edge of the third region, and a fourth outer peripheral edge located outside the fourth inner peripheral edge. The electrode described in any one of the appendices 1 to 4.

[0200] <Note 6> The present invention further comprises an insulating layer formed on the first, second, third, and fourth regions, at least a portion of which is disposed on the surface, having an inner peripheral edge that contacts the fourth peripheral edge of the fourth region in a plan view from a direction perpendicular to the surface, and including an opening that penetrates in the thickness direction. The electrodes described in Appendix 5.

[0201] <Note 7> The present invention further comprises an insulating layer, at least a portion of which is disposed on the surface portion, and which includes openings formed on the first region, the second region, and the third region and extending through in the thickness direction. The electrode described in any one of the appendices 1 to 5.

[0202] <Note 8> An electrode placed on an insulating substrate, A surface portion located on the opposite side of the substrate when placed on the substrate, A first region formed on the surface, including a first outer peripheral edge, wherein at least a portion of it has a first surface free energy, A second region is formed on the surface, including a second inner peripheral edge that surrounds the first region and is in contact with the first outer peripheral edge of the first region, and a second outer peripheral edge located outside the second inner peripheral edge, and having a second surface free energy greater than the first surface free energy, An insulating layer including an opening that penetrates in the thickness direction and has an inner peripheral edge that defines the second outer peripheral edge of the second region and is formed on the first region and the second region, with at least a part thereof disposed on the surface portion. An electrode provided with .

[0203] <Appendix 9> The entire first region has the first surface free energy. The electrode according to Appendix 8.

[0204] <Appendix 10> The first region includes a central region that is disposed inside the first region, is located inside the first outer peripheral edge of the first region, and has a surface free energy greater than the first surface free energy; a peripheral region that surrounds the central region, includes an inner peripheral edge that contacts the outer peripheral edge of the central region, and the first outer peripheral edge, and has the first surface free energy; and includes The electrode according to Appendix 8.

[0205] <000​​​​​​​​​​​​​​​​​​​​​​​ The sensor described in Appendix 12.

[0208] <Note 14> The device further comprises an insulating substrate on which the electrodes are arranged. The sensor described in Appendix 12 or 13.

[0209] <Note 15> The electrode described in any one of the appendices 1 to 11, A reagent layer comprising a reagent involved in a redox reaction, the first region and the second region of the electrode, the outer peripheral edge located on the second outer peripheral edge of the second region, and the reagent layer, A method for manufacturing a sensor comprising: The reagent layer is formed by applying a first liquid composition containing the reagent in a first solvent to the first and second regions of the electrode and then drying it. A method that includes this.

[0210] <Note 16> The first solvent comprises one or more selected from water and alcohols. The method described in Appendix 15.

[0211] <Note 17> The electrode described in any one of the appendices 1 to 11, A reagent layer comprising a reagent involved in a redox reaction, the first region and the second region of the electrode, the outer peripheral edge located on the second outer peripheral edge of the second region, and the reagent layer, A protective film covering the reagent layer, A method for manufacturing a sensor comprising: The reagent layer is formed by applying a first liquid composition containing the reagent in a first solvent to the first and second regions of the electrode and then drying it, and A second liquid composition containing a protective film component in a second solvent is applied to the surface portion of the electrode so as to cover the reagent layer, and then dried to form the protective film. A method that includes this.

[0212] <Appended Note 18> The electrode is the electrode described in Appended Note 5 or 6, The protective film is disposed so as to cover the reagent layer on the first region, the second region, the third region, and the fourth region of the electrode, and includes an outer peripheral edge portion located on the fourth outer peripheral edge portion of the fourth region, The formation of the protective film, includes applying the second liquid composition so as to cover the reagent layer on the first region, the second region, the third region, and the fourth region of the electrode and then drying it, The method described in Appended Note 17.

[0213] <Appended Note 19> A method for manufacturing the electrode described in Appended Note 6, having a partially untreated region for forming the first region, the second region, the third region, and the fourth region, and an untreated surface portion having the first surface free energy, and an insulating layer including an opening formed through the thickness direction on the untreated region, at least a part of which is disposed on the untreated surface portion, preparing an untreated electrode, and irradiating a laser beam onto an annular fourth untreated region disposed on the outer periphery of the untreated region adjacent to the inner peripheral edge portion of the opening of the insulating layer and an annular second untreated region disposed farther inside than the fourth untreated region in a plan view from a direction perpendicular to the untreated surface portion among the untreated regions of the untreated surface portion of the untreated electrode to convert the fourth untreated region into the fourth region and the second untreated region into the second region, A method including this.

[0214] <Appended Note 20> The method described in Appended Note 19, wherein irradiating the laser beam onto the fourth untreated region of the untreated region further includes irradiating the laser beam onto an opening peripheral region of the insulating layer surrounding the opening, which is adjacent to the outside of the fourth untreated region in a plan view from a direction perpendicular to the untreated surface portion.

[0215] <Appended Note 21> The method according to Appendix 20, further comprising irradiating the surrounding region of the aperture of the insulating layer with the laser light to destroy the insulating layer in the surrounding region of the aperture, and converting the portion of the untreated surface exposed by the destruction into the fourth region.

[0216] <Note 22> In the electrodes described in appendices 1 to 11, preferably, the first outer peripheral edge of the first region, and the second inner peripheral edge and second outer peripheral edge of the second region are circular. In the electrodes described in appendices 1 to 10, more preferably, if there is one or more selected from the third inner peripheral edge and third outer peripheral edge of the third region, and the fourth inner peripheral edge and fourth outer peripheral edge of the fourth region, they are circular. [Explanation of symbols]

[0217] 1: Sensor 2: Working electrode 3 :Reference pole 4: Opposite 5: Wiring 10: Electrode 10A: Untreated electrode 11: Surface part 11A: Untreated surface area 20: Circuit board 21: First side of the circuit board 30: Reagent layer 31: Peripheral edge of the reagent layer 40:Protective film 41: Peripheral edge of the protective film 50: Insulating layer 52: Opening 53:Reference pole opening 54: Counter electrode opening 55: Inner peripheral edge of the opening in the insulating layer 58: Area around the opening 110: 1st area 111: First outer edge 112: Central area 113: Peripheral edge of the central region 114: Inner peripheral edge of the surrounding region 115: Surrounding area 116: Connection area 120:Second area 121: Second inner peripheral edge 122: Second outer edge 130: Third area 131: Third inner peripheral edge 132: Third outer edge 140: 4th area 141: Fourth inner peripheral edge 142: Fourth outer edge 150: 5th area 151: Fifth inner peripheral area 500: Unprocessed area 510: First unprocessed area 520: Second unprocessed area 530: Third Unprocessed Area 540: Fourth unprocessed area C: Cell L: Liquid sample P: First liquid composition Q:Second liquid composition

Claims

1. An electrode placed on an insulating substrate, The surface portion of the electrode located on the opposite side of the substrate when placed on the substrate, A portion of the surface, including a first peripheral edge formed on the surface, and having a first surface free energy, A portion of the surface, comprising a second inner peripheral edge formed on the surface, surrounding the first region and in contact with the first outer peripheral edge of the first region, and a second outer peripheral edge located outside the second inner peripheral edge, the second region having a second surface free energy greater than the first surface free energy, A third region is a part of the surface portion, which is formed on the surface portion, surrounds the second region, includes a third inner peripheral edge that is in contact with the second outer peripheral edge of the second region, and has a third surface free energy smaller than the second surface free energy. Equipped with electrodes.

2. The third region further includes a third outer peripheral edge located outside the third inner peripheral edge, The surface further comprises a fourth region having a fourth surface free energy greater than the third surface free energy, which includes a fourth inner peripheral edge formed on the surface that surrounds the third region and is in contact with the third outer peripheral edge of the third region, and a fourth outer peripheral edge located outside the fourth inner peripheral edge. The electrode according to claim 1.

3. The present invention further comprises an insulating layer formed on the first, second, third, and fourth regions, at least a portion of which is disposed on the surface, and having an inner peripheral edge that contacts the fourth peripheral edge of the fourth region in a plan view from a direction perpendicular to the surface, and including an opening that penetrates in the thickness direction. The electrode according to claim 2.

4. The material further comprises an insulating layer, at least a portion of which is disposed on the surface portion, and which includes openings formed on the first region, the second region, and the third region and penetrating in the thickness direction. The electrode according to claim 1.

5. An electrode placed on an insulating substrate, The surface portion of the electrode located on the opposite side of the substrate when placed on the substrate, A portion of the surface, including a first peripheral edge formed on the surface, and having a first surface free energy, A portion of the surface, comprising a second inner peripheral edge formed on the surface, surrounding the first region and in contact with the first outer peripheral edge of the first region, and a second outer peripheral edge located outside the second inner peripheral edge, the second region having a second surface free energy greater than the first surface free energy, An insulating layer, at least a portion of which is disposed on the surface portion, is formed on the first region and the second region, has an inner peripheral edge that defines the second peripheral edge of the second region, and includes an opening that penetrates in the thickness direction, Equipped with electrodes.

6. An electrode according to any one of claims 1 to 5, A reagent layer comprising a reagent involved in the oxidation-reduction reaction, the first region and the second region of the electrode, the outer peripheral edge located on the second outer peripheral edge of the second region, and the reagent layer, A sensor equipped with the following features.

7. The reagent layer further comprises a protective film covering the reagent layer. The sensor according to claim 6.

8. The device further comprises an insulating substrate on which the electrodes are arranged. The sensor according to claim 6.

9. An electrode according to any one of claims 1 to 5, A reagent layer comprising a reagent involved in the oxidation-reduction reaction, the first region and the second region of the electrode, the outer peripheral edge located on the second outer peripheral edge of the second region, and the reagent layer, A method for manufacturing a sensor comprising: The reagent layer is formed by applying a first liquid composition containing the reagent in a first solvent to the first and second regions of the electrode, and then drying it. A method that includes this.

10. The first solvent comprises one or more selected from water and alcohols. The method according to claim 9.

11. An electrode according to any one of claims 1 to 5, A reagent layer comprising a reagent involved in the oxidation-reduction reaction, the first region and the second region of the electrode, the outer peripheral edge located on the second outer peripheral edge of the second region, and the reagent layer, A protective film covering the reagent layer, A method for manufacturing a sensor comprising: The reagent layer is formed by applying a first liquid composition containing the reagent in a first solvent to the first and second regions of the electrode and then drying it, and A second liquid composition containing a protective film component in a second solvent is applied to the surface portion of the electrode so as to cover the reagent layer, and then dried to form the protective film. A method that includes this.

12. The electrode according to claim 2 or 3, A reagent layer comprising a reagent involved in the oxidation-reduction reaction, the first region and the second region of the electrode, the outer peripheral edge located on the second outer peripheral edge of the second region, and the reagent layer, A protective film covering the reagent layer, which is arranged on the first, second, third, and fourth regions of the electrode to cover the reagent layer, and includes an outer peripheral edge located on the fourth outer peripheral edge of the fourth region, A method for manufacturing a sensor comprising: The reagent layer is formed by applying a first liquid composition containing the reagent in a first solvent to the first and second regions of the electrode and then drying it, and The first, second, third, and fourth regions of the electrode are coated with a second liquid composition containing a protective film component in a second solvent, and then dried to form the protective film. A method that includes this.

13. A method for manufacturing the electrode described in claim 3, To provide an untreated electrode comprising an untreated surface portion having an untreated area in part for forming the first, second, third, and fourth regions and having the first surface free energy, and an insulating layer having an opening formed on the untreated area and penetrating in the thickness direction, at least a portion of which is disposed on the untreated surface portion, and In the untreated electrode, within the untreated region of the untreated surface, in a plan view from a direction perpendicular to the untreated surface, a laser beam is irradiated onto an annular fourth untreated region located on the outer periphery of the untreated region adjacent to the inner peripheral edge of the opening of the insulating layer, and an annular second untreated region located further inward than the fourth untreated region, thereby converting the fourth untreated region into the fourth region and converting the second untreated region into the second region. A method that includes this.

14. The method according to claim 13, wherein irradiating the fourth untreated region of the untreated region with the laser light further includes irradiating the surrounding region of the insulating layer that surrounds the opening, which is adjacent to the outside of the fourth untreated region in a plan view from a direction perpendicular to the untreated surface.

15. The method according to claim 14, further comprising irradiating the surrounding region of the aperture of the insulating layer with the laser light to destroy the insulating layer in the surrounding region of the aperture, and converting the portion of the untreated surface exposed by the destruction into the fourth region.

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