Electrochemical sensor

Abstract

An electrochemical sensor (10) includes a plate-shaped member (11) having a first face and a second face in a front-back relationship, a supply flow path (11a) of a test liquid formed on the first face side, and a liquid storage path (15) disposed on the second face side of the plate-shaped member (11) to allow a portion of the test liquid to flow over a downstream end portion (11c) of the plate-shaped member (11). The electrochemical sensor (10) is configured such that, when the plate-shaped member (11) is viewed in plan, a liquid sampling opening (15a) that is an inlet of the liquid storage path (15) is located at a position that is apart from the upstream side of the supply flow path (11a) from the downstream end portion (11c).

Description

Technical Field

[0001] This invention relates to an electrochemical sensor for detecting specific components in a test solution using an electrochemical method. Background Technology

[0002] In recent years, for the diagnosis and prevention of diseases in test subjects, operations have been conducted to determine the concentration of specific components in test fluids such as urine using electrochemical sensors. In particular, since urine can be collected without harming the body, it is less burdensome for the test subject, making it a preferred test fluid. In this case, it is desirable to collect urine extremely simply, i.e., simply by the test subject directly urinating into the electrochemical sensor. Therefore, as an electrochemical sensor supplied with a test fluid that is as fluid as urine, there exists an electrochemical sensor configured such that when it comes into contact with the flow of the test fluid, the test fluid is filled into a liquid accumulation path through capillary action, thereby collecting a certain amount of test fluid, and bringing the sensor electrode into contact with the test fluid in the liquid accumulation path (for example, see Patent Document 1).

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2011-007717 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] However, in the existing electrochemical sensors described above, even after the test liquid is stored in the liquid storage path via capillary action, if the test liquid in contact with the sensor flows, an attractive force will be generated due to the affinity between the test liquids. This could potentially draw out the test liquid from the liquid storage path due to the flow of the test liquid. If the test liquid in the liquid storage path is drawn out, the amount of contact between the test liquid and the sensor electrode cannot be guaranteed, which may adversely affect the sensing results using the sensor electrode.

[0008] The present invention provides the following technology: after the test liquid is stored by utilizing capillary phenomenon, even if the test liquid in contact with the sensor flows, the attractive force generated by the flow of the test liquid can be weakened, and the stored test liquid can be suppressed from being drawn out.

[0009] Methods for solving problems

[0010] According to one aspect of the present invention, an electrochemical sensor is provided, comprising:

[0011] A plate-shaped member having a first surface and a second surface in an inside-out relationship, with a supply flow path for the tested liquid formed on the first surface side; and

[0012] A liquid storage path is disposed on the second surface side of the plate-shaped member, allowing a portion of the test liquid to flow in from the downstream end of the plate-shaped member where the supply flow path is formed.

[0013] When viewed from above, the liquid sampling port, which serves as the inlet to the liquid storage path, is located at a position that moves away from the downstream end towards the upstream side of the supply path.

[0014] The effects of the invention

[0015] According to the present invention, after the test liquid is stored using capillary action, even if the test liquid in contact with the sensor flows, the attractive force generated by the flow of the test liquid can be weakened, and the stored test liquid can be suppressed from being drawn out. Attached Figure Description

[0016] Figure 1 This is a perspective view schematically illustrating a specific example of how the electrochemical sensor according to the first embodiment of the present invention is used.

[0017] Figure 2 This is an exploded perspective view schematically showing an example of the configuration of an electrochemical sensor according to the first embodiment of the present invention.

[0018] Figure 3 This is a side cross-sectional view schematically illustrating an example of the processing operation of the main part of the electrochemical sensor according to the first embodiment of the present invention.

[0019] Figure 4 This is a partially enlarged view showing an example of the main components of an electrochemical sensor according to the first embodiment of the present invention.

[0020] Figure 5 This is a side view showing an example of the main components of an electrochemical sensor according to a second embodiment of the present invention.

[0021] Figure 6 This is an exploded perspective view schematically showing an example of the configuration of an electrochemical sensor according to a third embodiment of the present invention. Detailed Implementation

[0022] Hereinafter, one embodiment of the present invention will be described with reference to the accompanying drawings.

[0023] <First Implementation Method>

[0024] First, the first embodiment of the present invention will be described.

[0025] (Overview of electrochemical sensors)

[0026] The electrochemical sensor of this embodiment detects specific components in the test solution using an electrochemical method. In this embodiment, the detection of uric acid contained in urine collected from a test subject is taken as an example. That is, in this embodiment, urine collected from a test subject is exemplified as the test solution, and uric acid contained in the urine is exemplified as the specific component to be detected.

[0027] The detection of uric acid concentration in urine can be achieved, for example, by electrolyzing substances contained in urine under specific conditions and utilizing the resulting electrochemical reactions (e.g., redox reactions). This embodiment illustrates the detection of uric acid concentration in urine using a three-electrode method. The three-electrode method refers to a method that combines a working electrode, a counter electrode, and a reference electrode for electrochemical measurement.

[0028] Figure 1 This is a perspective view schematically illustrating a specific example of how the electrochemical sensor 10 of this embodiment is used.

[0029] As shown in the figure, the electrochemical sensor 10 of this embodiment is formed in the shape of a strip, and one end of it is inserted into the insertion port (groove) 21 of the measuring device 20 for use (see arrow A in the figure).

[0030] The measuring device 20 is, for example, a device called a potentiostat, configured to perform a predetermined voltage scanning operation while electrically connected to the electrodes of the electrochemical sensor 10 inserted into the insertion port 21. For this purpose, the measuring device 20 includes, for example, a voltage application section, a current measurement section, a potential difference measurement section, and a potential adjustment section. The voltage application section is configured to apply a voltage between the working electrode and the counter electrode in the electrochemical sensor 10 after a predetermined circuit is formed through connection with the electrochemical sensor 10. The current measurement section is configured to measure the current generated by the redox reaction of uric acid. The potential difference measurement section is configured to measure the potential difference between the working electrode and the reference electrode. The potential adjustment section is configured to maintain the potential of the working electrode constant based on the potential difference measured by the potential difference measurement section, using the potential of the reference electrode as a reference.

[0031] With the device 20 inserted into its insertion port 21, urine flowing due to the subject's urination is directly supplied to the electrochemical sensor 10 (see arrow B in the figure). As a result, at least the region near the end of the electrochemical sensor 10 opposite to the insertion end of the insertion port 21 comes into contact with the flow of urine, which is the test liquid.

[0032] When in contact with the flow of urine, the electrochemical sensor 10 collects a portion of the flowing urine using capillary action. The electrochemical sensor 10 then brings the collected urine into contact with the electrodes (i.e., the working electrode, the counter electrode, and the reference electrode). Thus, the concentration of uric acid in the collected urine can be detected using a three-electrode method.

[0033] (Example of an electrochemical sensor)

[0034] Here, a specific example of the configuration of the electrochemical sensor 10 of this embodiment will be described.

[0035] Figure 2 This is an exploded perspective view schematically showing an example of the configuration of the electrochemical sensor 10 of this embodiment. It should be noted that, for convenience, the constituent elements are shown in a separated state in the illustration.

[0036] The electrochemical sensor 10 of this embodiment includes a protective cover member 11, a flow path cover member 12, a spacer member 13, and a substrate 14, which are laminated together.

[0037] The protective cover member 11, used to cover and protect the electrodes 14a, 14b, and 14c on the substrate 14 (described later), is formed of a plate-like member having a first surface (e.g., a surface) and a second surface (e.g., a back surface) in an inside-out relationship. Furthermore, the protective cover member 11 is configured such that when urine (see arrow B in the diagram) is supplied to the electrochemical sensor 10 as the test liquid, the supplied urine flows along the first surface, thereby forming a urine supply flow path 11a on the first surface side.

[0038] The protective cover component 11 is formed of a water-resistant material, specifically any one of resin, ceramic, glass, paper, etc., preferably a resin material such as polyethylene (PE) or polyethylene terephthalate (PET). When the material is a resin material such as PE or PET, the thickness of the protective cover component 11 can be about 0.1 to 0.6 mm.

[0039] In the protective cover member 11, near the end opposite to the insertion end when the electrochemical sensor 10 is inserted into the insertion port 21 of the measuring device 20 (i.e., the downstream end of the supply flow path 11a), a through hole 11b extending through the thickness direction of the protective cover member 11 is provided. The planar shape of the through hole 11b is not particularly limited.

[0040] The flow path cover member 12 is configured to contact the second surface of the protective cover member 11, forming part of the wall surface of the liquid storage path 15, which will be described later. Furthermore, the flow path cover member 12 is provided with a slit groove 12a for forming a venting path connected to the liquid storage path 15. The end of the venting path formed by the slit groove 12a on the side opposite to the liquid storage path 15 is open to the atmosphere.

[0041] The flow path cover component 12 is formed of the same material as the protective cover component 11.

[0042] It should be noted that the flow path cover member 12 is laminated on the protective cover member 11 in the following manner: the downstream end 12b of the flow in the supply flow path 11a is located at a predetermined distance (see arrow C in the figure) upstream of the supply flow path 11a when viewed from above, compared to the position of the downstream end 11c in the protective cover member 11. Details of the predetermined distance are described later.

[0043] The spacer member 13 is disposed between the flow path cover member 12 and the substrate 14 to form the liquid storage path 15 described later. For this purpose, the spacer member 13 is provided with a cutout 13a for forming the liquid storage path 15.

[0044] The spacer member 13 is formed of the same material as the protective cover member 11 and the flow path cover member 12.

[0045] It should be noted that the spacer member 13 is also laminated on the flow path cover member 12 in the same manner as the flow path cover member 12, in the following state: the downstream end 13b of the flow in the supply flow path 11a is located at a predetermined distance (see arrow C in the figure) from the upstream side of the supply flow path 11a when viewed from above, compared to the position of the downstream end 11c in the cover member 11.

[0046] The substrate 14 supports a working electrode 14a, a counter electrode 14b, and a reference electrode 14c for detection based on the three-electrode method. The substrate 14 is configured such that each electrode 14a, 14b, and 14c is mounted in a region near the end 14e on the downstream side of the supply flow path 11a, and the side opposite to this end 14e becomes an insertion end into the insertion port 21 of the measuring device 20. Furthermore, the substrate 14 is provided with wiring 14d for individually connecting each electrode 14a, 14b, and 14c to the measuring device 20. For example, the working electrode 14a can be a chip-shaped electrode (diamond chip electrode) having a diamond film that generates a redox reaction corresponding to the applied voltage when urine is present. For the counter electrode 14b, for example, electrodes made of metals such as platinum (Pt), gold (Au), copper (Cu), palladium (Pd), nickel (Ni), and silver (Ag), diamond electrodes, boron-doped diamond (BDD) electrodes, carbon electrodes, etc., can be used. As the reference electrode 14c, for example, a silver / silver chloride (Ag / AgCl) electrode, a standard hydrogen electrode, a reversible hydrogen electrode, a palladium-hydrogen electrode, a saturated calomel electrode, a carbon electrode, a diamond electrode, or an electrode formed of metals such as Pt, Au, Cu, Pd, Ni, and Ag can be used. These electrodes 14a, 14b, and 14c, and the wiring 14d, can be constructed using known techniques, and detailed descriptions are omitted here.

[0047] The substrate 14 is formed of the same material as the protective cover member 11, the flow path cover member 12 and the spacer member 13.

[0048] It should be noted that the substrate 14 is also laminated on the spacer 13 in the same manner as the flow path cover member 12 and the spacer member 13, in the following state: the downstream end 14e of the flow in the supply flow path 11a is located at a predetermined distance (see arrow C in the figure) from the upstream side of the supply flow path 11a when viewed from above, compared to the position of the downstream end 11c in the protective cover member 11.

[0049] When the protective cover member 11, the flow path cover member 12, the spacer member 13 and the substrate 14 as described above are laminated, on the second side of the protective cover member 11, the cutout portion 13a of the spacer member 13 is clamped by the flow path cover member 12 and the substrate 14, thereby forming a space surrounded by them. This space constitutes the liquid storage path 15.

[0050] The liquid storage path 15 is configured to store a certain amount of urine in the space that serves as the liquid storage path 15. A portion of the urine supplied to the supply flow path 11a of the protective cover member 11 (see arrow B in the figure) flows past the downstream end 11c of the protective cover member 11 and into the liquid storage path 15 (see arrow D in the figure). Specifically, in urine with fluctuating flow rate and fluid shape, several μL or more of urine flows past the downstream end 11c through a few seconds of urine injection. Through such urine inflow, the space that serves as the liquid storage path 15 is filled with urine, thereby storing a certain amount of urine in the liquid storage path 15. The urine flowing into the liquid storage path 15 may also include urine that has passed through the through hole 11b of the protective cover member 11.

[0051] In the liquid storage path 15, electrodes 14a, 14b, and 14c on the substrate 14 are arranged facing the space that constitutes the liquid storage path 15. Thus, when urine flows into the liquid storage path 15, the electrodes 14a, 14b, and 14c come into contact with the urine.

[0052] The inflow of urine into the liquid storage path 15 is generated by capillary action. Therefore, the dimensions of the liquid storage path 15 (the width of the cut portion 13a, the thickness of the spacer member 13, etc.) are shaped to generate capillary action. Furthermore, in order to generate capillary action, the slit groove 12a of the flow path cover member 12 communicates with the liquid storage path 15, thereby forming a venting path (i.e., an air passage) connected to the liquid storage path 15. Specifically, regarding the dimensions of the liquid storage path 15, for example, if the width of the cut portion 13a is about 1 to 7 mm and the thickness of the spacer member 13 is about 0.1 to 0.6 mm, capillary action can be generated.

[0053] Furthermore, the inflow of urine into the liquid storage path 15 occurs through a sampling port 15a, which serves as the inlet of the liquid storage path 15. The sampling port 15a is located at the inner and outer boundaries of the space that forms the liquid storage path 15, and is formed by the end 12b of the flow path cover member 12, the end 13b of the spacer member 13, and the end 14e of the substrate 14. That is, the sampling port 15a is formed such that it is surrounded on all sides by the end edges of the flow path cover member 12, the spacer member 13, and the substrate 14. It should be noted that this example exemplifies the case where the ends 12b, 13b, and 14e are aligned to form a square-shaped sampling port 15a, but it is not necessarily limited to this. That is, the sampling port 15a only needs to be located at the inner and outer boundaries of the space; it does not necessarily have to be square, for example, it can also be formed as a circle. In addition, the positions of each end 12b, 13b, and 14e may not be fully aligned. In this case, a space is formed by surrounding at least three sides to become a liquid storage path 15. Therefore, the boundary inside and outside the space is defined by the position of the ends surrounding the three sides, and the liquid collection port 15a is located at this boundary.

[0054] The ends 12b of the flow path cover member 12, 13b of the spacer member 13, and 14e of the substrate 14 forming the sampling port 15a are all located at a predetermined distance (see arrow C in the figure) upstream of the supply flow path 11a from the downstream end 11c of the protective cover member 11. Therefore, the sampling port 15a is also located at a predetermined distance (see arrow C in the figure) from the downstream end 11c upstream of the supply flow path 11a when viewed from above the protective cover member 11. Details of the predetermined distance will be described later.

[0055] It should be noted that, in order to facilitate the inflow of urine into the liquid storage path 15, the surfaces of the walls constituting the liquid storage path 15, i.e., the flow path cover member 12, the spacer member 13, and the substrate 14 that surround the space forming the liquid storage path 15, are preferably hydrophilic treated surfaces. A hydrophilic treated surface refers to a surface that has undergone treatment to improve its affinity (i.e., hydrophilicity or wettability) with a liquid (e.g., water). Treatment to improve hydrophilicity can be performed using known techniques such as plasma treatment, and its detailed description is omitted here.

[0056] Regarding the walls constituting the liquid storage path 15, it is preferable that all surfaces are hydrophilic, but this is not necessarily the case; it is sufficient if at least one surface constituting the walls of the liquid storage path 15 is hydrophilic. Even in this case, compared to the case where no hydrophilic surfaces are present, it is easier for urine to flow into the liquid storage path 15.

[0057] In addition to the wall surface constituting the liquid storage path 15, a hydrophilic surface may also be disposed outside the wall surface. Specifically, the exposed portion of the second surface of the protective cover member 11 (the portion not covered by the flow path cover member 12, etc.), the end face of the downstream end 11c constituting the protective cover member 11, the end face of the downstream end 12b constituting the flow path cover member 12, the end face of the downstream end 13b constituting the spacer member 13, and the end face of the downstream end 14e constituting the substrate 14 may also be hydrophilic surfaces. If these surfaces are hydrophilic surfaces, urine can easily reach the liquid collection port 15a of the liquid storage path 15 from the supply flow path 11a.

[0058] (Example of processing actions in electrochemical sensors)

[0059] Next, an example of the processing operation of the electrochemical sensor 10 configured as described above in this embodiment will be explained.

[0060] Figure 3 This is a side cross-sectional view schematically showing an example of the processing operation of the main parts of the electrochemical sensor 10 of this embodiment.

[0061] When using the electrochemical sensor 10 of this embodiment to detect the uric acid concentration in a subject's urine, firstly, the electrochemical sensor 10 is connected to the measuring device 20. Then, the subject holds the measuring device 20, and simultaneously brings the electrochemical sensor 10, connected to the measuring device 20, into contact with the urine flowing from the subject's urination. Thus, a urine supply path 11a is formed in the electrochemical sensor 10 on the first surface side of the protective cover member 11.

[0062] When the urine supply path 11a is formed, a portion of the urine passing the downstream end 11c of the protective cover member 11 winds around to the second side of the protective cover member 11 and reaches the collection port 15a of the liquid storage path 15. Then, the urine reaching the collection port 15a flows into the space that serves as the liquid storage path 15 through capillary action and is filled into the space. Thus, in the liquid storage path 15, a certain amount of urine is stored and maintained in balance with the atmospheric pressure from the ventilation path formed by the slit groove 12a.

[0063] At this time, if a through hole 11b is provided in the protective cover component 11, the urine passing through the through hole 11b will also reach the liquid collection port 15a and flow into the liquid storage path 15. Therefore, the urine flowing in the supply flow path 11a can easily flow into the liquid storage path 15.

[0064] In addition, if the wall surface of the liquid storage path 15 is a hydrophilic surface, the resistance when urine flows into the liquid storage path 15 can be reduced, making it easier for urine to flow into the liquid storage path 15.

[0065] Furthermore, the ventilation passage formed by the slit groove 12a is connected to the liquid storage passage 15 into which urine flows. However, since the ventilation passage is covered by the protective cover member 11, urine will not flow into the liquid storage passage 15 from the ventilation passage side. That is, the ventilation passage is protected by the protective cover member 11, thereby maintaining a certain amount of urine in the liquid storage passage 15.

[0066] When a certain amount of urine accumulates in the liquid storage path 15, the working electrode 14a, counter electrode 14b, and reference electrode 14c on the substrate 14 come into contact with the urine within the liquid storage path 15. In this state, a predetermined voltage is applied from the measuring device 20 between the working electrode 14a and the counter electrode 14b. As a result, a redox reaction of uric acid occurs at the working electrode 14a, and a current (reaction current) flows within the working electrode 14a. The value of this reaction current is measured using the current measuring unit of the measuring device 20, for example, by cyclic voltammetry. The value of the reaction current can also be measured using methods such as square wave voltammetry (rectangular wave voltammetry), differential pulse voltammetry, conventional pulse voltammetry, and AC voltammetry. In addition, while in contact with urine, the potential difference (voltage difference) between the working electrode 14a and the reference electrode 14c is measured by the potential difference measuring unit of the measuring device 20.

[0067] Then, a cyclic voltammogram is constructed, for example, based on the value of the reaction current measured by the current measuring unit of the measuring instrument 20, to obtain the current value of the oxidation peak. Then, based on the obtained oxidation peak current value and the potential difference measured by the potential difference measuring unit of the measuring instrument 20, the concentration of uric acid in the urine is calculated (quantitatively). (See, for example, Anal.Methods, 2018.10, 991-996). Figure 3 , 4 The study disclosed a correlation between the value of the reaction current and the uric acid concentration. Therefore, if the relationship between the value of the reaction current and the uric acid concentration is determined in advance, the uric acid concentration can be quantified based on the measured value of the reaction current.

[0068] Through the above process, even when the urine, as the test solution, is supplied in a fluid state, the concentration of uric acid in the urine can be detected by electrochemical measurement.

[0069] However, urination from the subject usually continues for a certain period of time. Therefore, even after a certain amount of urine has accumulated in the liquid storage path 15, urine flow may still occur in the supply flow path 11a on the protective cover member 11.

[0070] In this case, since the urine flowing in the supply flow path 11a and the urine stored in the liquid storage path 15 are the same liquid, the liquid molecules attract each other through intermolecular forces, generating an attraction due to the affinity between the same liquids. That is, when urine flows in the supply flow path 11a, the attraction can act on the urine stored in the liquid storage path 15 through the flow of urine.

[0071] Therefore, for example, Figure 3 As shown in the reference example (b), when viewed from above, if the position of the downstream end 11c of the protective cover member 11 coincides with the position of the liquid collection port 15a of the liquid storage path 15, the urine in the liquid storage path 15 may be drawn out due to the suction force exerted by the flow of urine in the supply path 11a (see arrow E in the figure). If the urine in the liquid storage path 15 is drawn out, the amount of contact between the urine and the electrodes 14a, 14b, 14c on the substrate 14 cannot be guaranteed, which may adversely affect the sensing results using the electrodes 14a, 14b, 14c.

[0072] In contrast, the electrochemical sensor 10 of this embodiment is as follows: Figure 3 As shown in (a), the sampling port 15a of the liquid storage path 15 is located at a predetermined distance from the downstream end 11c of the protective cover member 11 towards the upstream side of the supply flow path 11a (see arrow C in the figure). That is, when viewed from the sampling port 15a of the liquid storage path 15, the flow of urine in the supply flow path 11a is blocked in accordance with the amount by which the downstream end 11c of the protective cover member 11 protrudes towards the downstream side of the supply flow path 11a. Therefore, even when urine flows into the liquid storage path 15 and urine is accumulated in the liquid storage path 15, the attraction of urine in the liquid storage path 15 caused by the flow of urine can be reduced in accordance with the amount by which the sampling port 15a moves away from the downstream end 11c (see dashed arrow E in the figure). Therefore, the electrochemical sensor 10 of this embodiment can suppress the situation where urine in the liquid storage path 15 is drawn out due to the flow of urine in the supply flow path 11a.

[0073] The specified distance between the downstream end 11c and the sampling port 15a (i.e., the amount of protrusion of the downstream end 11c as observed from the sampling port 15a) is set as follows.

[0074] The distance between the downstream end 11c and the collection port 15a is set such that urine passing through the downstream end 11c can bypass and reach the collection port 15a. Specifically, the distance that urine can reach the collection port 15a is set by taking into account the surface tension of urine, the wettability of the second surface of the protective cover member 11, etc.

[0075] Furthermore, the distance between the downstream end 11c and the collection port 15a is set to reduce the attraction of the urine flow in the supply flow path 11a to the urine in the liquid storage path 15. Specifically, the distance to reduce the attraction is set by taking into account the flow rate of the urine in the supply flow path 11a, the surface tension of the urine, etc. More specifically, this distance is a distance where the relationship is that the holding force of the urine in the liquid storage path 15 is greater than the attraction of the urine in the liquid storage path 15.

[0076] That is, the distance between the downstream end 11c and the collection port 15a is set such that when there is no urine in the liquid storage path 15, urine is routed to the collection port 15a, and when there is urine in the liquid storage path 15, the attraction of the urine flowing in the supply flow path 11a is reduced.

[0077] Regarding a specific example of this distance (protrusion amount), when the tested liquid is urine excreted from the human body, it is, for example, about 0.3 to 1.5 mm, preferably about 0.5 to 1.0 mm, and more preferably about 0.6 to 0.8 mm.

[0078] It should be noted that when the protective cover component 11 is provided with a through hole 11b, the diameter of the through hole 11b can be taken into account to set the distance between the downstream end 11c and the liquid collection port 15a.

[0079] However, even with the through hole 11b provided, the area of ​​the protective cover member 11 used to block the flow of urine in the supply flow path 11a can be ensured.

[0080] Figure 4 This is a partially enlarged view showing an example of the main components of the electrochemical sensor according to this embodiment.

[0081] Specifically, such as Figure 4 As shown in (a), even when the through hole 11b is provided, at least one of the following regions in the protective cover member 11—the region between the end 13b of the spacer member 13 and the upstream end of the through hole 11b, the region between the downstream end of the through hole 11b and the downstream end 11c of the protective cover member 11, and the regions located on both sides of the through hole 11b when viewed from the flow direction of urine in the liquid storage path 15—functions as a region for blocking the flow of urine in the supply flow path 11a. Therefore, even with the through hole 11b provided, the attraction to urine in the liquid storage path 15 can be reduced by this region of the protective cover member 11.

[0082] As described above, the electrochemical sensor 10 of this embodiment, through the positional relationship between the downstream end 11c of the protective cover member 11 and the liquid collection port 15a of the liquid storage path 15, can prevent urine in the liquid storage path 15 from being drawn out due to the flow of urine in the supply flow path 11a. Therefore, even when urine is supplied in a fluid state, a certain amount of urine can be maintained in the liquid storage path 15, thereby ensuring the amount of contact between the urine and the electrodes 14a, 14b, and 14c on the substrate 14.

[0083] (Effect)

[0084] According to this embodiment, one or more of the following effects are achieved.

[0085] (a) In this embodiment, when urine, which is the test liquid, is supplied to the first side of the protective cover member 11, a supply flow path 11a is formed on the first side, and the supplied urine flows in the supply flow path 11a. Then, a portion of the urine flowing in the supply flow path 11a goes around to the second side of the protective cover member 11, flows from the sampling port 15a into the liquid storage path 15 by capillary action, and accumulates in the liquid storage path 15. Therefore, by contacting the urine accumulated in the liquid storage path 15 with the electrodes 14a, 14b, and 14c on the substrate 14, the concentration of uric acid in the urine can be detected even when the urine, which is the test liquid, is supplied in a fluid state.

[0086] Furthermore, according to this embodiment, the sampling port 15a of the liquid storage path 15 is located at a position away from the downstream end 11c of the protective cover member 11 and upstream of the supply flow path 11a. Therefore, when urine is stored in the liquid storage path 15, even if urine flows in the supply flow path 11a, the amount of separation between the downstream end 11c and the sampling port 15a can correspondingly reduce the attraction of the urine flow to the urine in the liquid storage path 15, thereby preventing the urine in the liquid storage path 15 from being drawn out by the flow of urine in the supply flow path 11a. Therefore, even when urine is supplied in a fluid state, a certain amount of urine can be maintained in the liquid storage path 15. Thus, the contact amount between the urine and each electrode 14a, 14b, 14c on the substrate 14 is guaranteed, and the uric acid concentration in the urine can be detected with good accuracy using each electrode 14a, 14b, 14c.

[0087] (b) According to this embodiment, by providing a through hole 11b in the protective cover member 11, urine flowing in the supply flow path 11a can easily flow into the liquid storage path 15. That is, even if the downstream end 11c of the protective cover member 11 protrudes when viewed from the liquid collection port 15a of the liquid storage path 15, by utilizing the through hole 11b to allow urine to easily flow into the liquid storage path 15, it is possible to easily and reliably achieve a state in which a certain amount of urine is stored in the liquid storage path 15.

[0088] (c) According to this embodiment, by making the wall surface constituting the liquid storage path 15 a hydrophilic surface, the resistance when urine flows into the liquid storage path 15 can be reduced compared to the case where it is not a hydrophilic surface. Therefore, it is easy for urine to flow into the liquid storage path 15, thereby making it easy and reliable to achieve a state in which a certain amount of urine is stored in the liquid storage path 15.

[0089] (d) According to this embodiment, the slit groove 12a provided on the flow path cover member 12 constitutes a venting passage connected to the liquid storage passage 15, whereby urine flows from the collection port 15a into the liquid storage passage 15, where a certain amount of urine is stored. However, the venting passage is covered and protected by the protective cover member 11. Therefore, urine will not flow into the liquid storage passage 15 from the venting passage side, and a certain amount of urine can be reliably maintained in the liquid storage passage 15.

[0090] (Modified Example)

[0091] The first embodiment of the present invention has been described above, but the first embodiment is not necessarily limited to the above content and various changes can be made without departing from its spirit.

[0092] For example, in the first embodiment, urine was described as the test fluid, but the present invention is not limited to this method. For example, any test fluid supplied in a fluid state can be used, and in addition to urine, it can also be bodily fluids such as blood, saliva, nasal mucus, sweat, and tears. Furthermore, the test fluid is not limited to those from humans, and can also come from animals such as dogs and cats.

[0093] Furthermore, in the first embodiment, an example of uric acid being a specific substance contained in the test solution was described, but the present invention is not limited to this approach. For example, in addition to uric acid, other specific substances contained in the test solution may include urinary glucose, arginine, albumin, etc.

[0094] Furthermore, while the first embodiment described an example of determining the concentration of a specific component in the test solution using a three-electrode method, the present invention is not limited to this method. For example, the concentration of a specific substance in the test solution can also be determined using a two-electrode method. In this case, the sensor electrode only needs to have two electrodes: a working electrode and a counter electrode (or a reference electrode).

[0095] Furthermore, in the first embodiment, an example in which a through hole 11b is provided in the protective cover member 11 was described, but the present invention is not limited to this method. For example, as Figure 4 As shown in (b), a cutout 11d can be provided on the protective cover member 11 instead of the through hole 11b. When the cutout 11d is provided, similarly to the case of the through hole 11b, urine flowing in the supply flow path 11a can easily flow into the liquid storage path 15, and the attraction of urine in the liquid storage path 15 can be reduced by the area portion used to block the flow of urine in the supply flow path 11a.

[0096] Furthermore, in the first embodiment, an example was given where a slit groove 12a is provided on the flow path cover member 12, thereby forming a venting passage connected to the liquid storage passage 15. However, the present invention is not limited to this method. For example, the venting passage may also be formed by a slit-processed portion (not shown) formed on the spacer member 13, in which case the flow path cover member 12 may not be present. In addition, the venting passage connected to the liquid storage passage 15 may be formed by at least one of a groove-processed portion (not shown) formed on the substrate 14, or a through hole (not shown) formed in the substrate 14. Even when the through hole formed in the substrate 14 functions as a venting passage, since the through hole is located on the side opposite to the urine supply flow path 11a, urine can be prevented from flowing in from the venting passage side.

[0097] The length of the protective shield member 11 can be limited as long as it can prevent urine from flowing in from the ventilation path side. Specifically, for example, if the flow path shield member 12 has a slit groove 12a, the protective shield member 11 only needs to be long enough to protect the ventilation path. Alternatively, instead of the downstream end 11c of the protective shield member 11, the downstream end 12b of the flow path shield member 12 can be positioned to protrude beyond the spacer member 13. Even in this case, by making the end 12b of the flow path shield member 12 protrude beyond the spacer member 13, a portion of the urine can be guided into the liquid storage path 15, and the attraction of the urine in the liquid storage path 15 caused by the flow of the urine can be reduced. That is, with the configuration of the protective shield member 11 and the flow path shield member 12, their laminated body can function as a "plate-like member," and the effect described in the first embodiment can be achieved as long as at least one of the respective ends 11c and 12b is located away from the liquid collection port 15a of the liquid storage path 15.

[0098] Furthermore, in the first embodiment, the example given was of applying voltage during the pouring process to measure the concentration; however, the present invention is not limited to this method. For example, the same effect can be obtained even when voltage is applied to measure the concentration after the pouring is completed.

[0099] <Second Implementation Method>

[0100] Next, the second embodiment of the present invention will be described. Here, the differences from the first embodiment will be mainly explained.

[0101] Figure 5 This is a side view showing an example of the main components of the electrochemical sensor according to this embodiment.

[0102] As shown in the figure, in the electrochemical sensor of this embodiment, a bent portion 14f is provided on the substrate 14, which is one of the laminated components laminated with the protective cover component 11.

[0103] The bending portion 14f is a portion in which one side of the substrate 14 on which each electrode 14a, 14b, 14c is mounted (i.e., the side of the laminated protective cover member 11, etc.) is connected to the insertion side of the substrate 14 toward the measuring device 20 in a non-parallel manner. Non-parallel means that the sides are not parallel but intersect at a specified bending angle α.

[0104] When the subject holds the measuring device 20, which is inserted into the substrate 14 with this configuration, and is supplied with urine flowing from the subject's urination, the urine is incident at an angle β relative to the first surface of the protective cover member 11 deposited on the substrate 14, forming a supply flow path 11a on the first surface. The bending angle α of the bend 14f is set taking into account the urine's angle of incidence β, as will be explained below.

[0105] For example, the bending angle α of the bend 14f is set such that the incident angle β of the urine is as small as possible. Setting the bending angle α in this way suppresses the bounce of urine when it hits the first surface of the protective cover member 11, thus ensuring a sufficient flow rate of urine in the supply flow path 11a. Correspondingly, the amount of urine flowing around the second surface of the protective cover member 11 is also sufficiently ensured, which is highly preferable in terms of filling the liquid storage path 15 from the collection port 15a.

[0106] Furthermore, for example, the bending angle α of the bend 14f is set to be as large as possible according to the incident angle β of the urine. If the bending angle α is set in this way, the vector component along the supply flow path 11a becomes smaller, thus suppressing the flow velocity of urine flowing in the supply flow path 11a after it is incident on the first surface of the protective cover member 11. Therefore, due to the low flow velocity of the urine, even without increasing the amount of protrusion of the downstream end 11c of the protective cover member 11 from the liquid collection port 15a of the liquid storage path 15, the attraction to urine within the liquid storage path 15 can be reduced. That is, the amount of protrusion of the downstream end 11c can be suppressed to a small extent.

[0107] The other parts are configured in the same way as in the first embodiment.

[0108] According to the configuration in this embodiment as described above, in addition to one or more effects described in the first embodiment, the following effects are also achieved.

[0109] (e) According to this embodiment, a bend 14f is provided on the substrate 14. By setting the bending angle α of this bend 14f, the angle of incidence β of urine relative to the supply flow path 11a can be reduced or increased. Reducing the angle of incidence β is highly preferable for filling urine from the collection port 15a into the liquid storage path 15. Conversely, increasing the angle of incidence β reduces the attraction of urine to the liquid storage path 15 even without increasing the protrusion of the downstream end 11c of the protective cover member 11. Therefore, in either case, the ease of use for the subject using the electrochemical sensor is improved, resulting in excellent convenience for the subject.

[0110] The second embodiment of the present invention has been described above, but the second embodiment is not necessarily limited to the above content and various changes can be made without departing from its spirit.

[0111] For example, in the second embodiment, an example of having a bend 14f on the substrate 14 was described, but the present invention is not limited to this method. That is, the bend 14f can be provided on at least one of, for example, the protective cover member 11 or a laminated member (specifically, the flow path cover member 12, the spacer member 13, the substrate 14, etc.) that is laminated with the protective cover member 11. If it is provided on at least one of them, it is very convenient for the test subject.

[0112] <Third Implementation Method>

[0113] Next, the third embodiment of the present invention will be described. Here, the differences from the first or second embodiment will also be mainly described.

[0114] Figure 6 This is an exploded perspective view schematically showing an example of the configuration of the electrochemical sensor 10a according to this embodiment. It should be noted that, in the illustration, it is also related to... Figure 2 Similarly, for convenience, the constituent elements are shown in a separate state.

[0115] The electrode configuration of the electrochemical sensor 10a in this embodiment differs from that in the first or second embodiment.

[0116] In this embodiment, each electrode 14a, 14b, 14c on the substrate 14, especially at least the working electrode 14a, is covered by an enzyme membrane 14g.

[0117] The 14g enzyme membrane consists of an enzyme, an electron transporter, and a hydrophilic polymer. Known substances can be used for the enzyme, electron transporter, and hydrophilic polymer; detailed descriptions are omitted here.

[0118] This electrochemical sensor 10a, constructed with electrodes, utilizes electrons generated by the reaction of the substrate contained in the test solution with an enzyme to reduce an electron transporter. The measuring device 20 electrochemically measures the amount of electron transporter reduced, thereby performing quantitative analysis of the analyte. In other words, the electrochemical sensor 10a functions as an enzyme sensor that uses an enzyme as a molecular recognition element that specifically reacts with a particular substance in the test solution. It is equivalent to a sensor utilizing the molecular recognition capabilities of biomolecules such as microorganisms, enzymes, and antibodies—that is, a type of biosensor.

[0119] The other parts are configured in the same way as in the first or second embodiment. That is, the test liquid is supplied to the electrochemical sensor 10a in a fluid state, and the test liquid is stored in the liquid storage path 15 by capillary action. Furthermore, even if the test liquid flows in the supply flow path 11a in this state, since the downstream end 11c is separated from the sampling port 15a, it is possible to prevent the test liquid in the liquid storage path 15 from being drawn out by the flow of the test liquid in the supply flow path 11a, and to maintain a certain amount of test liquid stored in the liquid storage path 15.

[0120] As described above, this embodiment also achieves one or more of the effects described in the first or second embodiment.

[0121] This means that as long as the test solution is supplied in a fluid state, the characteristic configuration of the present invention is applicable not only to electrochemical sensors utilizing electrochemical reactions (e.g., redox reactions) but also to sensors utilizing the molecular recognition capabilities of biomolecules, i.e., biosensors. Furthermore, if the test solution is supplied in a fluid state, it is also possible to consider, for example, ion sensors utilizing ion-selective membranes capable of measuring ion components such as sodium and potassium ions in urine, which are the test solution. In the case of an ion sensor, an ion-selective membrane is used instead of an enzyme membrane (14g).

[0122] In other words, the electrochemical sensor of the present invention is applicable to a wide range of fields, including medical / pharmaceutical development, food, and environmental fields. Specifically, the electrochemical sensor of the present invention includes sensors that detect specific components in bodily fluids by utilizing electrochemical reactions (e.g., redox reactions), biosensors that utilize the molecular recognition capabilities of biomolecules, and ion sensors that use ion-selective membranes. With such an electrochemical sensor, by applying the characteristic structure of the present invention, even if the sample liquid in contact with the sensor flows after being accumulated using capillary action, the accumulated sample liquid can be suppressed from being drawn out.

[0123] <Preferred embodiments of the present invention>

[0124] The preferred embodiments of the present invention are described below.

[0125] (Postscript 1)

[0126] According to one aspect of the present invention, an electrochemical sensor is provided, comprising:

[0127] A plate-shaped member having a first surface and a second surface in an inside-out relationship, with a supply flow path for the tested liquid formed on the first surface side; and

[0128] A liquid storage path is disposed on the second surface side of the plate-shaped member, allowing a portion of the test liquid to flow in from the downstream end of the plate-shaped member where the supply flow path is formed.

[0129] When viewed from above, the liquid sampling port, which serves as the inlet to the liquid storage path, is located at a position that moves away from the downstream end towards the upstream side of the supply path.

[0130] (Postscript 2)

[0131] Preferably, the electrochemical sensor described in Appendix 1 is provided, wherein,

[0132] A through hole or cutout is provided near the downstream end of the aforementioned plate-shaped member.

[0133] (Note 3)

[0134] Preferably, the electrochemical sensor described in Appendix 1 or 2 is provided, wherein,

[0135] The walls that form the liquid storage path described above are hydrophilic.

[0136] (Postscript 4)

[0137] Preferably, an electrochemical sensor as described in any of Appendices 1 to 3 is provided, wherein,

[0138] It has a venting passage connected to the aforementioned liquid storage passage.

[0139] (Note 5)

[0140] Preferably, an electrochemical sensor as described in any of the embodiments in Appendix 1 to 4 is provided, wherein,

[0141] A bend is provided on at least one of the above-mentioned plate-shaped member or the laminated member laminated with the above-mentioned plate-shaped member.

[0142] (Note 6)

[0143] Preferably, an electrochemical sensor as described in any of the embodiments in Appendix 1 to 5 is provided, wherein,

[0144] It comprises spacer members and a substrate laminated on the aforementioned plate-shaped member.

[0145] The aforementioned spacer member is provided with a cutout for forming the aforementioned liquid storage path.

[0146] An electrode disposed within the liquid storage path is mounted on the aforementioned substrate.

[0147] The electrochemical sensor is configured to detect specific components in the test liquid by contacting the aforementioned electrodes with the test liquid flowing into the aforementioned liquid storage path.

[0148] (Note 7)

[0149] Preferably, an electrochemical sensor as described in any of the embodiments in Appendix 1 to 6 is provided, wherein,

[0150] The distance between the downstream end and the sampling port is set to a distance at which the relationship between the holding force of the tested liquid in the liquid storage path and the attraction force on the tested liquid in the liquid storage path holds true.

[0151] Symbol Explanation

[0152] 10, 10a electrochemical sensor

[0153] 11 Protective cover components

[0154] 11a Supply Flow Path

[0155] 11b Through hole

[0156] 11c Downstream end

[0157] 11d incision site

[0158] 12 Flow path hood components

[0159] 12a Slit Groove

[0160] 12b end

[0161] 13 Spacing Members

[0162] 13a Incision site

[0163] 13b end

[0164] 14 Substrate

[0165] 14a Working electrode

[0166] 14b Counter electrode

[0167] 14C reference electrode

[0168] 14d wiring

[0169] 14f Bend

[0170] 14g enzyme membrane (ion-selective membrane)

[0171] 15 Liquid storage path

[0172] 15a Liquid collection port

[0173] 20 Measuring Instrument

Claims

1. An electrochemical sensor comprising: A plate-shaped member having a first surface and a second surface that are in an inside-out relationship, with a supply flow path for the tested liquid formed on the first surface side; and A liquid accumulation path is disposed on the second surface side of the plate-shaped member, allowing a portion of the test liquid to flow in over the downstream end of the plate-shaped member where the supply flow path is formed. When viewed from above, the sampling port, which becomes the inlet of the liquid storage path, is located away from the downstream end towards the upstream side of the supply path.

2. The electrochemical sensor as described in claim 1, wherein, A through hole or cutout is provided near the downstream end of the plate-shaped member.

3. The electrochemical sensor as described in claim 1 or 2, wherein, At least one surface of the wall constituting the liquid storage path is a hydrophilic surface.

4. The electrochemical sensor as described in claim 1 or 2, wherein, It has a venting passage connected to the liquid storage passage.

5. The electrochemical sensor as described in claim 1 or 2, wherein, A bend is provided on at least one of the plate-shaped member or the laminated member laminated with the plate-shaped member.

6. The electrochemical sensor as described in claim 1 or 2, wherein, It comprises spacers and a substrate laminated on the plate-shaped member. The spacer member has a cutout for forming the liquid storage path. An electrode disposed within the liquid storage channel is mounted on the substrate. The electrochemical sensor is configured to detect specific components in the test liquid by contacting the electrode with the test liquid flowing into the liquid storage path.

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