Electrochemical sensor, multi-imposed sheet, and method of manufacturing electrochemical sensor

Abstract

To provide an electrochemical sensor that may offer improved sensitivity.SOLUTION: An electrochemical sensor is provided, comprising an insulative substrate 2, and an electrode 10 provided in a sensor area of the insulative substrate 2. The electrode 10 has an arithmetic mean roughness Ra of 0.3 or greater.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an electrochemical sensor, a multi-sided attachment sheet, and a method for manufacturing an electrochemical sensor.

Background Art

[0002] In recent years, biosensors have been widely used in fields such as medicine. A biosensor can detect an analyte in a sample by an electrochemical reaction. In a biosensor, a structure in which detection electrodes are formed on an insulating substrate is common. As the material of the electrodes, a carbon paste containing conductive carbon particles may be used from the viewpoint of suppressing manufacturing costs. However, a biosensor using carbon electrodes has a problem of low sensitivity.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present invention provides an electrochemical sensor, a multi-sided attachment sheet, and a method for manufacturing an electrochemical sensor capable of improving sensitivity.

Means for Solving the Problems

[0005] According to a first aspect of the present invention, there is provided an electrochemical sensor including an insulating substrate and an electrode provided in a sensor region of the insulating substrate, wherein an arithmetic mean roughness Ra of the electrode is 0.3 or more.

[0006] According to a second aspect of the present invention, there is provided an electrochemical sensor according to the first aspect, wherein the electrode has one or more particles having a particle diameter of 1.0 μm or more in a 40 μm square area.

[0007] According to a third aspect of the present invention, there is provided an electrochemical sensor according to the first aspect, wherein the electrode has one or more particles having a particle diameter of 2.5 μm or more in a 40 μm square area.

[0008] According to a fourth aspect of the present invention, there is provided an electrochemical sensor according to the first aspect, wherein the contact angle of the electrode is 25 degrees or less.

[0009] According to a fifth aspect of the present invention, there is provided an electrochemical sensor according to the first aspect, wherein the electrode is made of a conductive material mainly composed of carbon.

[0010] According to a sixth aspect of the present invention, there is provided an electrochemical sensor according to the first aspect, wherein the electrode includes a working electrode and a counter electrode disposed adjacent to the working electrode.

[0011] According to a seventh aspect of the present invention, there is provided an electrochemical sensor according to the sixth aspect, further including a first wiring and a second wiring provided on the insulating substrate and electrically connected to the working electrode and the counter electrode, respectively.

[0012] According to an eighth aspect of the present invention, there is provided an electrochemical sensor according to the sixth aspect, further including an insulating layer provided on the insulating substrate so as to insulate the working electrode and the counter electrode from each other.

[0013] According to a ninth aspect of the present invention, there is provided a multi-sided sheet including a plurality of electrode chips provided on a sheet-like insulating substrate, each of the plurality of electrode chips being an electrochemical sensor according to the first aspect.

[0014] According to the tenth aspect of the present invention, there is provided a method for manufacturing an electrochemical sensor, comprising: forming an electrode in a sensor region of an insulating substrate; polishing the electrode; and performing a surface treatment on the electrode so as to give roughness to the surface of the electrode after the step of polishing the electrode, wherein an arithmetic mean roughness Ra of the electrode is 0.3 or more.

[0015] According to the eleventh aspect of the present invention, there is provided a method for manufacturing an electrochemical sensor according to the tenth aspect, wherein in a 40 μm square area, there is at least one particle having a particle diameter of 1.0 μm or more on the electrode.

[0016] According to the twelfth aspect of the present invention, there is provided a method for manufacturing an electrochemical sensor according to the tenth aspect, wherein in a 40 μm square area, there is at least one particle having a particle diameter of 2.5 μm or more on the electrode.

[0017] According to the thirteenth aspect of the present invention, there is provided a method for manufacturing an electrochemical sensor according to the tenth aspect, wherein the electrode is made of a conductive material mainly composed of carbon.

[0018] According to the fourteenth aspect of the present invention, there is provided a method for manufacturing an electrochemical sensor according to the tenth aspect, wherein the electrode includes a working electrode and a counter electrode disposed adjacent to the working electrode.

Advantages of the Invention

[0019] According to the present invention, it is possible to provide an electrochemical sensor capable of improving sensitivity, a multi-sided attachment sheet, and a method for manufacturing an electrochemical sensor.

Brief Description of the Drawings

[0020]

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Embodiments for Carrying Out the Invention

[0021] Hereinafter, embodiments will be described with reference to the drawings. However, the drawings are schematic or conceptual, and dimensions, ratios, etc. of each drawing are not necessarily the same as those in reality. Also, even when representing the same part among the drawings, there may be cases where the dimensional relationships and ratios are different from each other. In particular, several embodiments shown below illustrate devices and methods for embodying the technical idea of the present invention, and the technical idea of the present invention is not specified by the shape, structure, arrangement, etc. of the components. In the following description, elements having the same function and configuration are denoted by the same reference numerals, and redundant descriptions are omitted.

[0022] In this embodiment, a biosensor will be described as an example of an electrochemical sensor. The biosensor can detect a specific substance in a biological sample, for example, by using an enzyme and utilizing an electrochemical reaction.

[0023] [1] Configuration of Biosensor 1 FIG. 1 is a plan view of a biosensor 1 according to an embodiment of the present invention. In FIG. 1, the X direction is a direction along one side of the biosensor 1, and the Y direction is a direction orthogonal to the X direction in the plane. FIG. 2 is a plan view of a plurality of layers constituting the biosensor 1 disassembled. FIG. 2(a) is a plan view of a first electrode pattern (including a working electrode 10 and a counter electrode 11). FIG. 2(b) is a plan view of an insulating layer pattern. FIG. 2(c) is a plan view of a second electrode pattern (including a reference electrode 30). The first electrode pattern in FIG. 2(a), the insulating layer pattern in FIG. 2(b), and the second electrode pattern in FIG. 2(c) are laminated in this order. FIG. 3 is a cross-sectional view of the biosensor 1 taken along the line A-A' in FIG. 1. FIG. 4 is a cross-sectional view of the biosensor 1 taken along the line B-B' in FIG. 1.

[0024] The biosensor 1 includes an insulating substrate 2, a working electrode 10, a counter electrode 11, a connection electrode 12, an insulating layer 20, and a reference electrode 30. Among the insulating substrate 2, the region where the working electrode 10 and the counter electrode are arranged is called the sensor region. The sensor region is the region where an electrochemical reaction occurs.

[0025] The insulating substrate 2 is made of an insulating material such as plastic, glass, or ceramic. Examples of the above-mentioned plastic include polyethylene terephthalate (PET), polyester, polystyrene, polypropylene, polycarbonate, polyimide, and acrylic resin.

[0026] The working electrode 10 is provided on the insulating substrate 2. The working electrode 10 is an electrode for detecting a measurement target. On the working electrode 10, a substance that causes an electrochemical reaction (oxidation and reduction) with the sample solution to be measured is fixed. The working electrode 10 has, for example, a circular shape. The working electrode 10 is made of a conductive material and is made of a metal or a carbon electrode, etc. The carbon electrode is made of a conductive material mainly composed of carbon. Carbon includes carbon black, graphite, and carbon nanotubes. Carbon may be composed of a mixture of carbon black and graphite. The working electrode 10 may be made of a conductive paste containing conductive particles and a binder (resin). From the viewpoints of corrosion resistance and cost, it is desirable that the working electrode 10 be made of a carbon paste. The carbon paste contains, for example, carbon, resin, a curing agent, and a solvent.

[0027] On the insulating substrate 2, a counter electrode 11 is provided. The counter electrode 11 is an electrode paired with the working electrode 10 and is an electrode for flowing the current generated at the working electrode 10. The counter electrode 11 is arranged with a space from the working electrode 10 so as to surround a part of the periphery of the working electrode 10. In the present embodiment, the counter electrode 11 is configured to extend along approximately half of the periphery of the working electrode 10. The counter electrode 11 can use the same conductive material as the working electrode 10. The counter electrode 11 may use a conductive material different from that of the working electrode 10.

[0028] On the insulating substrate 2, a connection electrode 12 is provided. The connection electrode 12 is an electrode electrically connected to the reference electrode 30. The connection electrode 12 is arranged adjacent to the working electrode 10 in a region other than the region where the counter electrode 11 is arranged. The connection electrode 12 has a rectangle extending in the X direction. The connection electrode 12 can use the same conductive material as the working electrode 10. The connection electrode 12 may use a conductive material different from that of the working electrode 10.

[0029] On the insulating substrate 2, wirings 13 to 15 are provided. The wirings 13 to 15 are each configured to extend in the Y direction. The wiring 13 is electrically connected to the working electrode 10. The wiring 13 is made of the same conductive material as the working electrode 10. The wiring 14 is electrically connected to the connection electrode 12. The wiring 14 is made of the same conductive material as the connection electrode 12. The wiring 15 is electrically connected to the counter electrode 11. The wiring 15 is made of the same conductive material as the counter electrode 11.

[0030] On the insulating substrate 2, the connection electrode 12, and the wirings 13 to 15, an insulating layer 20 is provided. The insulating layer 20 is made of an insulating material, for example, resin. Examples of the above resin include epoxy resin and phenolic resin. The insulating layer 20 is preferably made of a resin that can be formed in a printing process, and preferably made of a thermosetting resin or a UV (ultraviolet) curable resin. The insulating layer 20 includes a first portion 21 for insulating the working electrode 10 and the counter electrode 11, a second portion 22 for covering the wiring, and a plurality of openings 23 to 26.

[0031] The first part 21 of the insulating layer 20 is configured to surround the working electrode 10 and is formed in an annular shape. The first part 21 is disposed between the working electrode 10 and the counter electrode 11 and insulates the working electrode 10 from the counter electrode 11. The first part 21 has a function of preventing a substance fixed on the working electrode 10 from coming into contact with the counter electrode 11.

[0032] The second part 22 of the insulating layer 20 is configured to cover the connection electrode 12 and the wirings 13 - 15. The second part 22 is provided to insulate the wirings 13 - 15.

[0033] The opening 23 partially exposes the connection electrode 12. The opening 24 partially exposes the end of the wiring 13. The opening 25 partially exposes the end of the wiring 14. The opening 26 partially exposes the end of the wiring 15. The three wiring portions respectively exposed by the openings 24 - 26 among the wirings 13 - 15 are used as the three terminals T1 - T3 of the biosensor 1.

[0034] A reference electrode 30 is provided on the connection electrode 12. The reference electrode 30 has a rectangle extending in the X direction in a plan view. The reference electrode 30 is provided in the opening 23 and on the connection electrode 12 so as to partially overlap the insulating layer 20. In other words, the reference electrode 30 is provided in the opening 23 and on the connection electrode 12 such that both ends in the X direction overlap the insulating layer 20. The reference electrode 30 is an electrode that generates a reference potential. The reference electrode 30 is preferably made of a conductive material and a material with a stable potential when current flows. The reference electrode 30 is composed of, for example, a silver / silver chloride electrode.

[0035] The biosensor 1 is configured as described above. The terminals T1 - T3 of the biosensor 1 are connected to the connector of the electrochemical detection device.

[0036] As a method of using the biosensor 1, a mediator layer is deposited on the working electrode 10. The mediator layer functions as an electron transfer substance. On the mediator layer, a reactant such as a biological material, for example, a redox enzyme, is deposited. On the redox enzyme, a protective film (not shown) is formed, for example. When using the biosensor 1, a predetermined potential difference is applied between the counter electrode 11 and the working electrode 10 with reference to the potential of the reference electrode 30. The sample solution that has penetrated the protective film reacts with the redox enzyme to generate a target substance. As a result, a current corresponding to the concentration of the target substance flows between the working electrode 10 and the counter electrode 11. The electrochemical detection device can measure the current value flowing between the working electrode 10 and the counter electrode 11 and measure the concentration of the target substance in the sample solution based on the measurement result.

[0037] The biosensor 1 of the present embodiment can measure, for example, the blood glucose level or the lactic acid level in a biological sample.

[0038] [2] Manufacturing method Next, the manufacturing method of the biosensor 1 will be described with reference to the drawings. FIG. 5 is a flowchart for explaining the manufacturing method of the biosensor 1.

[0039] First, an insulating substrate 2 is prepared. The insulating substrate 2 is composed of, for example, a PET film. Subsequently, a pretreatment is performed on the PET film as the insulating substrate 2 (step S100). Specifically, the insulating substrate 2 is heat-treated (annealed). In this heat treatment, heat equal to or higher than the heat treatment temperature in the subsequent process is applied to the insulating substrate 2 so that the insulating substrate 2 does not change in dimensions due to the heat history in the subsequent process. Subsequently, using a die-cutting blade, holes for printing stage positioning and printing alignment are formed in the insulating substrate 2.

[0040] Subsequently, a screen printing machine for performing screen printing is prepared. Alignment pins are provided on the stage of the screen printing machine. Subsequently, the insulating substrate 2 is set on the stage by inserting the holes of the insulating substrate 2 into the pins of the stage, and the insulating substrate 2 is vacuum-sucked on the stage.

[0041] Subsequently, an electrode pattern is formed on the insulating substrate 2 using a screen printing method (step S101). FIG. 6 is a plan view for explaining the process of forming the electrode pattern. FIG. 7 is a cross-sectional view taken along line B-B' of FIG. 6. The electrode pattern includes a working electrode 10, a counter electrode 11, a connection electrode 12, and wirings 13 to 15. Specifically, a screen printing plate with a pattern for the electrode is prepared. Using the screen printing plate and the squeegee of the screen printing machine, a conductive paste is screen printed onto the insulating substrate 2. As the conductive paste, a carbon paste is used. Subsequently, the carbon paste is cured. In this curing process, it is cured by heating or UV irradiation.

[0042] Subsequently, the electrode pattern is polished (step S102). The polishing process is performed using a polishing device. As the polishing device, for example, a device that performs polishing using a polishing film is used. By performing the polishing process on the electrode, the electrode surface can be activated.

[0043] Subsequently, an insulating layer 20 is formed using a screen printing method (step S103). FIG. 8 is a plan view for explaining the process of forming the insulating layer 20. FIG. 9 is a cross-sectional view taken along line B-B' of FIG. 8. The insulating layer 20 includes a first portion 21 for insulating the working electrode 10 and the counter electrode 11, a second portion 22 for covering the wiring, and a plurality of openings 23 to 26. Specifically, using a screen printing plate with a pattern for the insulating layer 20, an insulating paste is screen printed onto the insulating substrate 2 and the electrodes. As the insulating paste, a thermosetting resin or a UV curable resin is used. The insulating paste is preferably a thermosetting type insulating paste that does not contain the main solvent of the carbon paste, or a solvent-free UV curable type insulating paste. As the thermosetting type insulating paste, a material containing an epoxy resin and a curing agent is used. As the UV curable type insulating paste, a material containing an epoxy resin and a photoinitiator is used. Subsequently, the insulating paste is cured. In this curing process, it is cured by heating or UV irradiation.

[0044] Subsequently, as shown in FIGS. 1, 3, and 4, a reference electrode 30 is formed on the connection electrode 12 using a screen printing method. Specifically, using a screen printing plate with a pattern for the reference electrode, a conductive paste is screen printed onto the connection electrode 12 and within the opening 23 of the insulating layer 20. As the conductive paste, a paste mainly composed of silver silver chloride (referred to as a silver silver chloride paste) is used. Subsequently, the silver silver chloride paste is thermally cured.

[0045] Subsequently, surface treatment is performed on the exposed electrodes (mainly the working electrode 10 and the counter electrode 11) (step S105). The surface treatment in this embodiment is mainly performed for the purpose of giving roughness to the surface of the electrodes. As methods for surface treatment of the electrodes, ultraviolet irradiation, vacuum plasma, and atmospheric pressure plasma are used, and further, they are performed in a combined process combining two or more of these. By this surface treatment, roughness is formed on the surface of the electrodes, and a plurality of particles are formed on the surface of the electrodes. The state of the surface of the electrodes will be described later.

[0046] In this embodiment, the plurality of biosensors 1 are formed on a common sheet in a multi-sided attachment manner. A sheet on which the plurality of biosensors 1 are multi-sidedly attached is called a multi-sided attachment sheet. FIG. 10 is a plan view of the multi-sided attachment sheet 40. The multi-sided attachment sheet 40 includes a plurality of electrode chips 41. In FIG. 10, 56 (= 8 × 7) electrode chips 41 are shown as an example. The electrode chip 41 corresponds to the biosensor 1 described above. In FIG. 10, one electrode chip 41 is shown in a simplified rectangular shape.

[0047] The plurality of electrode chips 41 are provided on a sheet-like insulating substrate 2. The plurality of electrode chips 41 are manufactured using the same screen printing process. Thereby, the manufacturing cost of the electrode chips 41 can be reduced.

[0048] Subsequently, a plurality of multi-sidedly attached biosensors 1 are chip-formed (step S106). Specifically, for example, by dicing, the insulating substrate 2 is divided for each biosensor 1. In this way, a plurality of biosensors 1 are manufactured.

[0049] [3] Detailed configuration of the electrodes of the biosensor 1 Next, the detailed configuration of the electrodes of the biosensor 1 will be described. The electrodes of the biosensor 1 mean the electrodes exposed from the insulating layer 20 and include the working electrode 10 and the counter electrode 11.

[0050] FIG. 11 is a diagram for explaining the surface state of the electrodes of the biosensor 1. FIG. 11(a) is a diagram showing the surface state of the electrodes subjected to the surface treatment of the present embodiment. FIG. 11(b) is a comparative example and shows the surface state of the electrodes without surface treatment. FIG. 11 is an SEM image obtained by a scanning electron microscope (SEM). The dashed square in FIG. 11 indicates a 40 μm square area.

[0051] From FIG. 11, it can be understood that the electrodes with surface treatment have roughness on the surface. It can be understood that the electrodes without surface treatment do not have roughness on the surface.

[0052] The electrodes with surface treatment have a plurality of particles provided on the surface. The particles are particles made of carbon. In the present embodiment, the size of the particles is defined by the particle diameter. The particle diameter is the maximum length when the particle is projected onto a plane.

[0053] In FIG. 11(a), particles with a particle diameter of 1.0 μm and particles with a particle diameter of 2.5 μm are indicated by arrows. In the present embodiment, in the electrodes (working electrode 10 and counter electrode 11), there is at least one particle with a particle diameter of 1.0 μm or more in the 40 μm square area. Also, in the electrodes (working electrode 10 and counter electrode 11), there is at least one particle with a particle diameter of 2.5 μm or more in the 40 μm square area.

[0054] Next, the results of evaluating the surface roughness of the electrode will be described. The surface roughness was measured using an atomic force microscope (AFM). The surface roughness was evaluated using the arithmetic mean roughness Ra and the maximum height Rz. The arithmetic mean roughness Ra follows the definition according to the JIS standard "JIS B 0601:2013". The maximum height Rz is represented by the difference between the highest part and the lowest part within the reference length.

[0055] Figure 12 is a diagram showing the measurement results of the surface roughness of the electrode. Figure 12 shows the results of fabricating and evaluating five biosensors (samples) for each with and without surface treatment. Figure 12 shows the arithmetic mean roughness Ra and the maximum height Rz on the electrode surface of the biosensor. Also, Figure 12 shows the average value (Ave) of Ra and Rz, and the range (Range) of Ra and Rz.

[0056] From Figure 12, it can be understood that the arithmetic mean roughness Ra and the maximum height Rz of the biosensor with surface treatment are larger than those of the biosensor without surface treatment, respectively. Therefore, it can be understood that by performing the surface treatment of this embodiment, the surface roughness of the electrode of the biosensor increases. From the average value of the arithmetic mean roughness Ra in Figure 12, it is desirable that the arithmetic mean roughness Ra of the electrode is 0.3 or more. From the average value of the maximum height Rz in Figure 12, it is desirable that the maximum height Rz of the electrode is 3 or more. By providing roughness on the surface of the electrode, the surface area of the electrode can be increased.

[0057] Next, the results of evaluating the electrochemical characteristics of the biosensor 1 will be described. The electrochemical characteristics of the biosensor 1 can be evaluated using the cyclic voltammetry (CV) method. The CV method is performed using a potentiostat. The potentiostat controls the voltage between the working electrode 10 and the reference electrode 30 and measures the current flowing between the working electrode 10 and the counter electrode 11 in a three-electrode system consisting of the working electrode 10, the counter electrode 11, and the reference electrode 30. That is, the potential of the working electrode 10 is changed with reference to the potential of the reference electrode 30. When the potential is swept to the negative side, a reduction reaction occurs, and when the potential is swept to the positive side, an oxidation reaction occurs.

[0058] In this embodiment, the peak current value was measured by the CV method, and the electrochemical characteristics of the biosensor 1 were evaluated based on the peak current value. As the peak current value, the peak current value in the oxidation reaction (referred to as the oxidation peak current value) was measured. In the CV measurement, an electrolytic solution containing 0.3 M sodium sulfate and 2 mM potassium ferricyanide was used as the measurement sample solution. This solution was dropped onto the working electrode 10 and the counter electrode 11.

[0059] FIG. 13 is a diagram for explaining the results of measuring the oxidation peak current value in the biosensor 1. FIG. 13 shows the results of fabricating and evaluating four biosensors (samples). That is, the four biosensors consist of (1) a sample without surface treatment of the electrode (without treatment in the figure), (2) a sample subjected to a specific first surface treatment (treatment A in the figure), (3) a sample subjected to a specific second surface treatment (treatment B in the figure), and (4) a sample subjected to a specific third surface treatment (treatment C in the figure). The surface treatments of treatments A to C include each of the above-described plurality of surface treatments alone and combinations of two or more of the plurality of surface treatments. The surface treatments of treatments A to C are different from each other.

[0060] In FIG. 13, (1) the oxidation peak current value in the biosensor without treatment is 11.5 μA, (2) the oxidation peak current value in the biosensor of treatment A is 19.2 μA, (3) the oxidation peak current value in the biosensor of treatment B is 21.8 μA, and (4) the oxidation peak current value in the biosensor of treatment C is 27.5 μA. By performing a specific surface treatment (treatment C), the oxidation peak current value can be increased to 27.5 μA.

[0061] Next, the results of evaluating the background current in the electrochemical characteristics of the biosensor 1 will be described. In the CV measurement, among the currents flowing through the electrode, in addition to the target Faraday current, a charging current (non-Faraday current) that flows to charge the electric double layer on the electrode surface also flows. The background current is an unwanted current that flows among the currents flowing through the electrode in addition to the target Faraday current. It is desirable that the background current be smaller. In this embodiment, the background current in the oxidation reaction was measured.

[0062] FIG. 14 is a diagram for explaining the results of measuring the background current in the biosensor 1. FIG. 14 shows the measurement results of samples subjected to treatment B and treatment C as the surface treatment of the electrode.

[0063] Depending on the content of the surface treatment, the value of the background current also differs. The background current of treatment B is 2.93 μA, and the background current of treatment C is 1.56 μA. By performing a specific surface treatment (treatment C), the background current can be reduced to 1.56 μA.

[0064] Next, the results of evaluating the wettability of the electrode surface of the biosensor 1 will be described. In the evaluation of the wettability of the electrode surface, the contact angle of the solution was measured. The solution is the same as the sample solution described above. The contact angle is the angle formed between the surface of the electrode and the tangent of the liquid droplet. It can be evaluated that the lower the contact angle, the higher the hydrophilicity of the electrode. In this embodiment, the wettability and the contact angle are evaluated using pure water.

[0065] Figure 15 is a diagram showing the relationship between the contact angle and the oxidation peak current value. The horizontal axis of Figure 15 represents the contact angle (degrees), and the vertical axis represents the oxidation peak current value (μA). Figure 15 shows the results of evaluating the wettability using five biosensors (samples) with a specific surface treatment on the electrodes.

[0066] In Figure 15, the regression line is represented by "y = -0.8145x + 38.708", and the coefficient of determination is represented by "R 2 = 0.9913". It can be understood from Figure 15 that there is a relationship between the contact angle and the oxidation peak current value. In the present embodiment, by performing a specific surface treatment on the electrode, the contact angle at the electrode (including the working electrode 10) can be made 25 degrees or less.

[0067] [4] Effects of the Embodiment In the present embodiment, by performing a specific surface treatment on the electrode (including the working electrode 10 and the counter electrode 11), the surface of the electrode is made rough. According to the present embodiment, the electrode surface of the biosensor 1 can be activated. Thereby, the electrochemical characteristics of the biosensor 1 can be improved. In addition, the sensitivity of the biosensor 1 can be improved. Furthermore, the rate of the electrochemical reaction in the biosensor 1 can be improved.

[0068] Also, in the CV measurement, the oxidation peak current value can be increased. Thereby, the sensitivity of the biosensor 1 can be improved.

[0069] Also, in the CV measurement, the background current can be decreased. Thereby, the sensitivity of the biosensor 1 can be improved.

[0070] Also, the wettability and hydrophilicity of the electrode in the biosensor 1 can be improved. Thereby, the sensitivity of the biosensor 1 can be improved.

[0071] In addition, the biosensor 1 can be manufactured using a screen printing process. Thereby, the manufacturing cost of the biosensor 1 can be reduced.

[0072] In addition, a plurality of biosensors 1 can be formed in a multi-sided manner using a screen printing process. Thereby, the manufacturing cost of the biosensor 1 can be reduced. In addition, mass production of the biosensor 1 becomes possible, and an inexpensive and disposable biosensor 1 can be manufactured.

[0073] In the above embodiment, a biosensor is exemplified and described as an electrochemical sensor. However, the present invention is not limited to this, and the electrochemical sensor of the present embodiment is also applicable to gas sensors, water quality inspection sensors, soil inspection sensors, residual pesticide detection sensors, and the like.

[0074] The present invention is not limited to the above embodiments, and various modifications can be made without departing from the gist thereof at the implementation stage. In addition, each embodiment may be implemented in appropriate combination, and in that case, the combined effects can be obtained. Furthermore, the above embodiments include various inventions, and various inventions can be extracted by combinations selected from a plurality of disclosed constituent elements. For example, even if some constituent elements are deleted from all the constituent elements shown in the embodiment, if the problem can be solved and the effect can be obtained, the configuration from which these constituent elements are deleted can be extracted as an invention.

Explanation of Reference Numerals

[0075] 1... Biosensor, 2... Insulating substrate, 10... Working electrode, 11... Counter electrode, 12... Connection electrode, 13 - 15... Wiring, 20... Insulating layer, 23 - 26... Opening, 30... Reference electrode, 40... Multi-sided attachment sheet, 41... Electrode chip, T1 - T3... Terminal.

Claims

1. An insulating substrate, An electrode provided in a sensor region of the insulating substrate, Comprising, The arithmetic mean roughness Ra of the electrode is 0.3 or more Electrochemical sensor.

2. In a 40 μm square area of the electrode, there is at least one particle having a particle diameter of 1.0 μm or more The electrochemical sensor according to Claim 1.

3. In a 40 μm square area of the electrode, there is at least one particle having a particle diameter of 2.5 μm or more The electrochemical sensor according to Claim 1.

4. The contact angle of the electrode is 25 degrees or less The electrochemical sensor according to Claim 1.

5. The electrode is made of a conductive material mainly composed of carbon The electrochemical sensor according to Claim 1.

6. The electrode includes a working electrode and a counter electrode disposed adjacent to the working electrode The electrochemical sensor according to Claim 1.

7. Further comprising a first wiring and a second wiring provided on the insulating substrate and electrically connected to the working electrode and the counter electrode respectively The electrochemical sensor according to Claim 6.

8. Further comprising an insulating layer provided on the insulating substrate so as to insulate the working electrode and the counter electrode from each other The electrochemical sensor according to Claim 6.

9. Comprising a plurality of electrode chips provided on a sheet-shaped insulating substrate, Each of the plurality of electrode chips is the electrochemical sensor according to Claim 1 Multi-sided attached sheet.

10. A step of forming an electrode in a sensor region of an insulating substrate, A step of polishing the electrode, After the step of polishing the electrode, a step of performing a surface treatment on the electrode so as to give roughness to the surface of the electrode, Comprising, The arithmetic mean roughness Ra of the electrode is 0.3 or more Method for manufacturing an electrochemical sensor.

11. In a 40 μm square area of the electrode, there is at least one particle having a particle diameter of 1.0 μm or more The method for manufacturing an electrochemical sensor according to Claim 10.

12. In a 40 μm square area of the electrode, there is at least one particle having a particle diameter of 2.5 μm or more The method for manufacturing an electrochemical sensor according to Claim 10.

13. The electrode is made of a conductive material mainly composed of carbon The method for manufacturing an electrochemical sensor according to Claim 10.

14. The electrode includes a working electrode and a counter electrode disposed adjacent to the working electrode The method for manufacturing an electrochemical sensor according to Claim 10.

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