JP6749721B1 - Electrochemical sensor unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrochemical sensor unit capable of stably and accurately detecting the concentration of a specific component in a test sample. SOLUTION: A base material, a sensor electrode provided on one of two main surfaces of the base material, and an intake capable of taking in a liquid test sample are opened to cover the sensor electrode. A sheet provided on one surface of the base material is provided so that the peripheral edge of the sheet and the base material are adhered to each other, and the test sample taken in from the intake is stored and brought into contact with the sensor electrode. The structure is constructed, and the storage structure has an outlet for discharging a part of the test sample taken in through the intake. [Selection diagram] Figure 2

Description

The present disclosure relates to an electrochemical sensor unit that measures the concentration of a specific component contained in a liquid test sample.

In recent years, an electrochemical sensor unit including a base material, a sensor electrode mounted on the base material, and a sheet provided so as to cover the sensor electrode has been disclosed as a patented technology (Patent Document 1). reference). In this sensor unit, a liquid test sample (test substance solution) introduced from an inlet formed in a sheet is brought into contact with a sensor electrode, and the concentration of a specific component contained in the test sample is measured.

Japanese Patent No. 6653847

The above-mentioned patented technology widely contributes to the industry in that the concentration of a specific component in a test sample can be measured simply and reliably, but rarely, even though the concentration itself of the specific component does not change. Therefore, it was found that the concentration measurement result may not be stable. This is a novel problem that was first revealed by the inventors' earnest research. The present disclosure aims to provide an electrochemical sensor unit capable of more stably and accurately measuring the concentration of a specific component in a test sample.

According to one aspect of the present disclosure,
Base material,
A sensor electrode provided on any one of the two main surfaces of the base material;
An inlet capable of taking in a liquid test sample is opened, and a sheet provided on the one surface of the base material so as to cover the sensor electrode,
A peripheral structure of the sheet and the base material are adhered to each other, and a storage structure for storing a test sample taken in through the inlet and contacting the sensor electrode is formed,
The storage structure is provided with an electrochemical sensor unit having an outlet for ejecting a part of the test sample introduced via the inlet.

According to the present disclosure, it becomes possible to provide an electrochemical sensor unit capable of more stably and accurately measuring the concentration of a specific component in a test sample.

FIG. 3 is an exploded perspective view of an electrochemical sensor unit according to an aspect of the present disclosure. FIG. 3 is a schematic top view of an electrochemical sensor unit according to an aspect of the present disclosure. FIG. 3 is an enlarged schematic top view of a portion where a sensor electrode of an electrochemical sensor unit according to an aspect of the present disclosure is arranged. The respective cyclic voltammograms obtained by performing cyclic voltammetry with the amount of urine contacting the sensor electrode being high, medium, and low are shown. FIG. 8 is a schematic top view of an electrochemical sensor unit according to a modified example of one aspect of the present disclosure.

<Findings obtained by the inventor>
As described above, when a sensor unit with a structure with a sheet is used, the concentration measurement result may not be stable even though the concentration itself of the specific component in the test sample does not change. It was found that the concentration of the specific component may be measured as a concentration higher than the actual concentration or as a concentration lower than the actual concentration. The inventor has diligently studied the cause of this novel problem. As a result, in a sensor structure having a structure with a sheet that covers the sensor electrode, a sensor unit having another structure, for example, without the structure with a sheet, the electrode portion is immersed in the test sample stored in the container. We found that the amount of test sample that comes into contact with the sensor electrode tends to fluctuate more than that of a sensor unit of the type that makes it possible that this is one factor that affects the measurement result of concentration. .. The present invention has been made based on this finding.

<One aspect of the present disclosure>
Hereinafter, one aspect of the present disclosure will be described mainly with reference to FIGS. 1 to 3. In this embodiment, an electrochemical sensor unit that measures the concentration of a specific component contained in a liquid test sample by the three-electrode method will be described as an example.

(1) Configuration of Electrochemical Sensor Unit As shown in FIG. 1, the electrochemical sensor unit (hereinafter, unit) 100 according to this embodiment includes a base material 10, a sensor electrode 20, and a sheet 30. The unit 100 is configured to be disposable.

The unit 100 is used with a measuring instrument connected so as to be capable of performing a predetermined voltage sweep operation on the sensor electrode 20. In the unit 100, a liquid test sample (in this embodiment, urine collected from a subject, as an example) is brought into contact with the sensor electrode 20, and a predetermined voltage sweep operation is performed on the sensor electrode 20 from the measuring device to obtain urine. A specific component (uric acid in this embodiment, for example) contained therein is electrolyzed under specific conditions, and the concentration of uric acid is measured by a measuring instrument from the magnitude of an electrochemical reaction (for example, redox reaction) that occurs at that time. can do.

The base material 10 is configured to support the sensor electrode 20. The base material 10 is composed of a sheet-shaped (plate-shaped) member, and is formed in a longitudinal shape. The base material 10 has, for example, a long-shaped portion (main portion) 11 and a convex portion 12. The convex portion 12 is a portion that is clamped by a connecting portion of the measuring instrument described later or is inserted into the insertion port of the measuring instrument, that is, a portion that functions as a connecting terminal.

The length of the main part 11 is, for example, 90 mm or more and 150 mm or less, the width of the main part 11 is, for example, 6 mm or more and 12 mm or less, and the thickness of the main part 11 is, for example, 0.2 mm or more and 2 mm or less, preferably 0.3 mm or more and 1 mm or less. Can be In this specification, when the word "length" is used, it means the length of the base material 10 in the longitudinal direction, and when the word "width" is used, the length of the base material 10 in the width direction. Means

The length of the convex portion 12 is, for example, 5 mm or more and 15 mm or less, and the width of the convex portion 12 and the thickness of the convex portion 12 can be the same width and thickness as the main portion 11, respectively. When the convex portion 12 is inserted into the insertion opening of the measuring instrument, the width of the convex portion 12 is, for example, about 2 mm to 4 mm narrower than the width of the main portion 11, although it depends on the shape of the insertion opening. Can be width. The crank portion is formed by the difference between the width of the main portion 11 and the width of the convex portion 12, and this crank portion limits the insertion length when the convex portion 12 is inserted into the insertion port of the measuring instrument. Functions as a stopper. Further, for example, the thickness of the convex portion 12 may be smaller than that of the main portion 11, and the crank portion may be configured by the difference between the thickness of the main portion 11 and the thickness of the convex portion 12.

The base material 10 has physical (mechanical) strength that can be used as the unit 100, for example, strength that does not bend or break even when urine adheres. The base material 10 is made of an insulating material. As the insulating material, plastic, glass epoxy resin, ceramic, glass or the like can be used. As the base material 10, for example, a rigid board or a flexible board can be used.

The sensor electrode 20 is provided on one of the two main surfaces of the base material 10. Hereinafter, the main surface of the base material 10 on which the sensor electrode 20 is provided is also referred to as “upper surface of the base material 10 ”. The sensor electrode 20 is provided on one end side in the longitudinal direction of the base material 10. Specifically, the sensor electrode 20 is provided on the main portion 11 of the base material 10 and in the vicinity of the end portion on the opposite side of the convex portion 12 in the longitudinal direction of the base material 10.

Three wirings (conductor wirings) 13, 14 and 15 (hereinafter also referred to as wirings 13 to 15) are provided on the upper surface of the base material 10 from the convex portion 12 of the base material 10 toward the sensor electrode 20. They are provided apart from each other without making contact with each other. From the viewpoint of surely connecting the unit 100 and a measuring device to be described later, it is preferable that the wirings 13 to 15 are respectively provided up to the end of the convex portion 12 opposite to the side adjacent to the main portion 11. ..

The wirings 13 to 15 can be formed using a metal such as copper (Cu) or aluminum (Al). The wirings 13 to 15 may be made of the same material or different materials.

The wirings 13 to 15 are formed by, for example, a subtractive method in which an unnecessary portion of the copper film previously attached to the base material 10 and not covered with the resist is removed by etching to form a necessary conductor pattern. Can be formed. The wirings 13 to 15 can also be formed using an additive method or the like. Further, for example, gold (Au) plating or silver (Ag) plating may be applied onto these conductor patterns formed by the subtractive method or the additive method. The wirings 13 to 15 can also be formed by a printing method such as screen printing, gravure printing, offset printing, inkjet printing, or a vapor deposition method.

The sensor electrode 20 has a working electrode 21, a counter electrode (counter electrode) 22, and a reference electrode 23. One end of the wiring 13 is connected to the working electrode 21, one end of the wiring 14 is connected to the counter electrode 22, and one end of the wiring 15 is connected to the reference electrode 23.

As the working electrode 21, for example, an electrode formed of a metal of Ag, Au, platinum (Pt) or Cu can be used. As the working electrode 21, a carbon electrode, a conductive diamond electrode doped with boron (B), or the like can be used. Further, as the working electrode 21, it is possible to use an electrode or the like made of various known materials according to the type of the specific component to be measured. The working electrode 21 can be formed by using a known method such as an additive method or a subtractive method. The working electrode 21 can be formed, for example, by applying a predetermined plating to a conductor pattern formed integrally with the wiring 13 by using a subtractive method. The working electrode 21 can also be formed by attaching a predetermined material to a conductor pattern formed integrally with the wiring 13 described later.

Further, on the surface of the working electrode 21, as a functional film that allows only a specific component (for example, uric acid) to permeate or a functional film that reacts only with this specific component, for example, a predetermined surface decoration film such as an enzyme-containing film or an ion exchange film is provided. It may be provided.

The counter electrode 22 is an electrode for flowing a current generated by an electrochemical reaction to the working electrode 21, and is provided so as to surround the working electrode 21 and a reference electrode 23 described later. The electrode area of the counter electrode 22 is preferably larger than the electrode area of the working electrode 21. As the counter electrode 22, an electrode formed of a metal such as Pt, Au, Cu, palladium (Pd), nickel (Ni), Ag, or a carbon electrode can be used. The counter electrode 22 can be formed integrally with the wiring 14 by a known method such as a subtractive method or an additive method.

The reference electrode 23 is an electrode serving as a reference when determining the potential of the working electrode 21, and is provided near the working electrode 21. As the reference electrode 23, a silver/silver chloride (Ag/AgCl) electrode or the like can be used. Further, as the reference electrode 23, a standard hydrogen electrode, a reversible hydrogen electrode, a palladium/hydrogen electrode, a saturated calomel electrode, a carbon electrode or the like can be used. Further, as the reference electrode 23, an electrode formed of a metal such as Pt, Au, Cu, Pd, Ni or Ag can be used. The reference electrode 23 can be formed by attaching a predetermined material (for example, AgCl) to a conductor pattern formed integrally with the wiring 15 by using a subtractive method or an additive method. Further, for example, a conductor pattern formed integrally with the wiring 15 may be plated with gold or the like and used as the reference electrode 23.

A sheet-like waterproof member 40 that prevents urine from adhering to the wirings 13 to 15 is provided on the upper surface of the base material 10. The waterproof member 40 is configured to cover (seal) the wirings 13 to 15 located on the main portion 11 and expose the wirings 13 to 15 and the sensor electrode 20 located on the convex portion 12. The waterproof member 40 can be formed using a material having impermeable and insulating properties such as plastic, silicon resin, Teflon (registered trademark) resin, and rubber.

A sheet (sheet-shaped member) 30 is provided on the upper surface of the base material 10 so as to cover the sensor electrode 20 and the waterproof member 40. The sheet 30 includes a water repellent member 31 that does not absorb urine and a water absorbing member 32 that absorbs urine.

The water repellent member 31 may be in the form of a sheet (plate), for example. The length of the water repellent member 31 is, for example, about 15 mm to 25 mm longer than the length of the base material 10 (the total length of the length of the main portion 11 and the length of the convex portion 12). It is preferable that the protrusions 12 are arranged so as to protrude from the side of the convex portion 12. Thus, when the unit 100 is connected to the measuring instrument, the portion of the water repellent member 31 protruding from the convex portion 12 (hereinafter, also referred to as “protruding portion of the water repellent member 31 (or the sheet 30)”) is pinched. It can be turned over, and a part of the upper surface of the base material 10, for example, the convex portion 12 functioning as a connection terminal can be easily exposed. Further, when the unit 100 is connected to the measuring instrument, the connecting portion (insertion port, pinching portion, etc.) of the measuring instrument can be covered with the water repellent member 31. As a result, it is possible to avoid the infiltration of urine into the measuring instrument, and it is possible to improve the reliability of the measurement and the like. In addition, when performing the measurement, the finger of the subject who holds (holds) the unit (measuring device connected to the unit) can be covered with the water-repellent member 31, so that urine adheres to the finger of the subject. It is also possible to prevent The length of the water repellent member 31 may be the same as the length of the base material 10. The width of the water repellent member 31 can be the same as the width of the base material 10 (main part 11). The thickness of the water repellent member 31 can be, for example, 0.01 mm or more and 0.3 mm or less.

The water repellent member 31 can be formed by using paper whose surface is coated with a water repellent material such as plastic, silicon resin, or Teflon (registered trademark) resin. For the water repellent member 31, a sheet-shaped resin formed of the above water repellent material can be used.

The water repellent member 31 is provided with an intake port (opening) 33 capable of taking in urine. The intake port 33 is opened so as to be located on the sensor electrode 20 when the sheet 30 is arranged. The intake 33 can be, for example, a circular shape having a diameter of 2 mm or more and 5 mm or less. The inlet 33 is not limited to a circular shape and may be a rectangular shape or the like.

A water absorbing member 32 is provided (attached) to the water repellent member 31 so as to close the intake port 33. The water absorbing member 32 is formed in a sheet shape, for example, and is configured to absorb the urine supplied to the unit 100 and bring it into contact with the surface of the sensor electrode 20. The water absorbing member 32 has a size that covers at least a part of the surface of the sensor electrode 20 (working electrode 21, counter electrode 22, and reference electrode 23). Although the water absorbing member 32 may be provided on the front surface side of the water repellent member 31, it is preferably provided on the back surface (the surface facing the base material 10) of the water repellent member 31, as shown in FIG. In this case, the water absorbing member 32 is arranged inside the storage structure described later, and functions to reliably store urine in the storage structure.

By adjusting the plane area and the thickness of the water absorbing member 32, it becomes possible to easily appropriately control the amount of urine stored in the storage structure, that is, the amount of urine to be brought into contact with the sensor electrode 20. .. As shown in FIG. 1 and the like, the plane area of the water absorbing member 32 is preferably larger than the plane area of the sensor electrode 20. The plane area of the water absorbing member 32 can be, for example, 10 mm ² or more and 50 mm ² or less. As a result, urine can be surely brought into contact with the entire surface of the sensor electrode 20 and the sensitivity of concentration measurement can be increased. The plane area of the water absorbing member 32 may be smaller than the plane area of the sensor electrode 20. The thickness of the water absorbing member 32 can be, for example, 0.01 mm or more and 1.0 mm or less.

When the water absorbing member 32 is attached to the water repellent member 31 using an adhesive, the position where the adhesive is applied is preferably a position that does not face the sensor electrode 20. Further, the water absorbing member 32 may be attached to the water repellent member 31 without using an adhesive. For example, the water absorbing member 32 may be attached to the water repellent member 31 by providing the water repellent member 31 with a cut portion, inserting the water absorbing member 32 into the cut portion, and sandwiching the water absorbing member 32 with the water repellent member 31. .. By doing so, it is possible to reduce the adverse effect of the substance contained in the adhesive on the measurement result.

The water absorbing member 32 can be formed using natural fibers, pulp fibers, regenerated fibers, synthetic fibers, or the like. Specifically, the water absorbing member 32 can be formed by using a filter paper, a membrane filter, a glass filter, a filter cloth, or the like. The water absorbing member 32 can also be formed by adding water absorbing polymer particles or the like to the above-mentioned aggregate composed of one or more fibers. The water absorbing member 32 may be formed using a member made of a porous material such as sponge or diatomaceous earth, or a fibrous material such as nonwoven fabric.

As shown in FIGS. 2 and 3, the peripheral edge of the sheet 30 (that is, the water repellent member 31) and the base material 10 are bonded to each other with an adhesive 51 or the like. Specifically, the peripheral edge of the sheet 30 and the peripheral edge of the central portion in the longitudinal direction of the base material 10 and the peripheral edge on the side where the sensor electrode 20 is provided are adhered to each other with an adhesive 51. .. As a result, the urine taken in through the intake port 33 is stored in the space between the base material 10 and the sheet 30 (between the waterproof member 40 and the sheet 30 where the waterproof member 40 is provided). A storage structure (bag-shaped structure) that is brought into contact with the sensor electrode 20 is configured. The bonding between the sheet 30 and the base material 10 is not limited to the case where the adhesive 51 is used, and various methods such as heat fusion, sewing, and fitting can be used. Note that the sheet 30 and the waterproof member 40 are omitted in FIG. 3 for the sake of clarity.

The storage structure has a discharge port 52 for discharging a part of urine taken into the storage structure via the intake port 33. The outlet 52 is configured so that the amount of urine that contacts the sensor electrode 20 can be adjusted. The discharge port 52 stores excess urine, which has been taken into the storage structure via the intake port 33 and could not be completely absorbed by the water absorbing member 32, outside the storage structure (unit 100) to be stored in the storage structure. The amount of urine to be discharged, that is, the amount of urine to be brought into contact with the sensor electrode 20 is made constant (to a predetermined amount). As a result, it is possible to prevent fluctuations in the measurement result of uric acid concentration in urine and to accurately and stably measure the uric acid concentration in urine. That is, it is possible to stabilize the measurement accuracy of the uric acid concentration by the unit 100.

If the storage structure is not provided with the discharge port 52, it becomes difficult to adjust the amount of urine that contacts the sensor electrode 20, and the amount of urine that contacts the sensor electrode 20 becomes excessive (a predetermined amount Be exceeded). In this case, although the actual uric acid concentration in the urine does not change (the concentration does not increase), the output of the detection signal of the unit 100 becomes larger than expected, and the uric acid concentration is measured higher than the actual concentration. It may be done. On the other hand, in this aspect, since the amount of urine that contacts the sensor electrode 20 can be adjusted to a constant amount using the outlet 52, the uric acid concentration in urine can be measured accurately and accurately. It becomes possible to carry out stably.

The discharge port 52 can be configured by using various known check valves, but as shown in FIGS. 1 to 3, the discharge port 52 is based on a part of the peripheral edge of the sheet 30 that constitutes the storage structure. It can be configured by not adhering to the material 10. With such a configuration, the discharge port 52 can be easily provided, and the unit 100 can be prevented from becoming complicated, large-sized, and expensive.

The discharge port 52 is preferably arranged at a position where the sensor electrode 20 is arranged on the urine flow path from the intake port 33 to the discharge port 52. That is, it is preferable that the sensor electrode 20 is arranged on the flow path of urine from the intake port 33 to the discharge port 52. As a result, the amount of urine in contact with the sensor electrode 20 can be reliably kept constant, and the uric acid concentration in urine can be measured accurately and stably.

If the sensor electrode 20 is not arranged in the urine flow path, the urine taken in through the intake port 33 will not reach the sensor electrode 20 easily, and the amount of urine contacting the sensor electrode 20 will be too small (predetermined amount). Less than). In this case, although the actual uric acid concentration in the urine does not change (the concentration does not decrease), the output of the detection signal of the unit 100 is smaller than expected, and the uric acid concentration is lower than the actual concentration. It may be done. If the sensor electrode 20 is not arranged on the flow path of urine, the excess urine that should pass over the sensor electrode 20 becomes difficult to be discharged from the discharge port 52, and a large amount of urine remains on the sensor electrode 20. As a result, the amount of urine contacting the sensor electrode 20 may become excessive. In this case, although the actual uric acid concentration in the urine does not change (the concentration does not increase), the output of the detection signal of the unit 100 becomes larger than expected, and the uric acid concentration is measured higher than the actual concentration. It may be done. If the sensor electrode 20 is not arranged on the urine flow path as described above, the accuracy of measurement of the uric acid concentration by the unit 100 may become unstable. On the other hand, in this aspect, since the sensor electrode 20 is arranged on the urine flow path, the amount of urine contacting the sensor electrode 20 can be ensured to be a constant amount, and the uric acid concentration in urine can be measured. Can be performed accurately and stably.

The position and size of the discharge port 52 are such that the discharge port 52 overlaps at least a part of the sensor electrode 20 when the unit 100 is viewed from the side (when the unit 100 is viewed from the side). It is preferable that the outlet 52 be located and sized so as to include all of the sensor electrodes 20.

Further, the discharge ports 52 are preferably provided at a plurality of positions so that excess urine in the storage space can be discharged smoothly regardless of the posture of the unit 100. For example, as in the present embodiment, when the unit 100 is viewed from the sheet 30 side (when the unit 100 is viewed in plan), the discharge port 52 is in a direction orthogonal to the longitudinal direction of the base material 10 (width of the base material 10). It is preferably provided on both sides of the (direction). That is, it is preferable that the discharge ports 52 are provided on both sides in the width direction of the base material 10 with the sensor electrode 20 interposed therebetween when the unit 100 is viewed in plan.

By adopting at least one of these configurations, the excess urine taken in the storage structure can be discharged without tilting or shaking the unit 100 after applying the urine, Further, it can be performed more reliably regardless of the posture of the unit 100. That is, the above-described action and effect that the amount of urine brought into contact with the sensor electrode 20 by the discharge using the discharge port 52 is made constant and the uric acid concentration in the urine is measured accurately and stably can be applied to an artificial operation of a subject or the like. It will come out more reliably and naturally without relying on it.

The size of the discharge port 52 can be appropriately set according to the size (planar area) of the water absorbing member 32, the water absorbing capacity (capacity of urine that can be absorbed), and the like. For example, when the surplus space in the storage structure is large, the plane area of the water absorbing member 32 is small, or the water absorbing capacity of the water absorbing member 32 is low, that is, excess urine is likely to remain in the storage structure and the sensor electrode 20 is contacted. When the amount of urine to be discharged is likely to be excessive, the size of the discharge port 52 (the length of the non-adhesive portion) may be made longer than the length of the water absorbing member 32 in the longitudinal direction of the base material 10. Further, when the surplus space in the storage structure is small, the plane area of the water absorbing member 32 is large, or the water absorbing capacity of the water absorbing member 32 is high, that is, excess urine is unlikely to remain in the storage structure and contacts the sensor electrode 20. When the amount of urine to be discharged is likely to be too small, the size of the discharge port 52 may be shorter than the length of the water absorbing member 32 in the longitudinal direction of the base material 10. As a result, the amount of urine to be brought into contact with the sensor electrode 20 is likely to be appropriate and constant, and the uric acid concentration can be measured more accurately and stably.

The periphery of the sheet 30 and the base material 10 may have a non-adhesive portion in addition to the portion forming the discharge port 52.

For example, in FIG. 2, when the vertical and horizontal directions of the paper surface are defined as the vertical and horizontal directions when the unit 100 is viewed in plan, the peripheral edge of the sheet 30 and the left end of the base material 10 may be non-bonded. It should be noted that in the following, in FIG. 2, the left and right directions of the plane of the drawing are simply referred to as "left side end of the base material 10" when the left and right directions of the unit 100 are defined as the vertical and horizontal directions when the unit 100 is viewed in plan. ". However, as shown in FIG. 2, by adhering this portion, it is possible to avoid the exposure of the sensor electrode 20 due to the curling of the edge of the sheet 30, and as a result, the sebum of the subject adheres to the sensor electrode 20 and its sensitivity It is possible to avoid such a situation that the power consumption is lowered or the sensor electrode 20 is damaged.

Further, for example, as shown in FIG. 2, the peripheral portion of the sheet 30 and the peripheral portion of the convex portion 12 of the base material 10 and the peripheral portion of the peripheral portion of the main portion 11 on the convex portion 12 side are mutually formed. It may be non-adhesive. This makes it easier to flip the water repellent member 31 and expose the convex portion 12.

Note that, as in the present embodiment, the sheet 30 and the base material 10 are bonded to each other at least at any one of the locations (preferably at two or more locations), so that the relative displacement of the sheet 30 with respect to the base material 10 is prevented. It goes without saying that the reliability can be maintained and the unit 100 can be suppressed.

(2) Method of Measuring Uric Acid Concentration Using Electrochemical Sensor Unit Next, an example of a method of measuring uric acid concentration in urine by electrochemical measurement using the unit 100 will be described.

In the uric acid concentration measuring method using the unit 100,
Electrically connecting the unit 100 and the measuring device (step 1),
Supplying urine to the unit 100 and bringing the urine into contact with the sensor electrode 20 (step 2),
When urine is in contact with the surface of the sensor electrode 20, a predetermined voltage sweep operation is performed on the sensor electrode 20 from the measuring device to electrolyze uric acid contained in urine under specific conditions, which occurs at that time. The step of measuring the uric acid concentration in urine from the magnitude of the electrochemical reaction (step 3) is performed in this order. In this aspect, step 2, step 1, and step 3 may be performed in this order.

(Step 1)
In this step, the unit 100 and a measuring device (not shown) formed separately from the unit 100 are connected to each other. For example, the test subject holds the unit 100, and pinches the protruding portion of the sheet 30 covering the base material 10 to turn it over to expose the convex portion 12 of the base material 10 that functions as a connection terminal (see FIG. 2 ). A measuring device is connected to the convex portion 12. The measuring device is configured so that the connecting portion of the measuring device and the wirings 13 to 15 can be electrically connected only by sandwiching the convex portion 12 together with the wirings 13 to 15. The measuring instrument has an insertion opening (slot) into which the convex portion 12 is inserted, and by simply inserting the convex portion 12 into this insertion opening, the connecting portion of the measuring instrument and the wirings 13 to 15 are electrically connected. It may be configured to be connectable.

The measuring device is configured to be capable of performing a predetermined voltage sweep operation on the sensor electrode 20, and includes a voltage sweep operation unit, a current measuring unit, a potential adjusting unit, a display unit, a wireless communication unit, and the like. ing. The above-mentioned respective parts of the measuring device are connected to each other so that data can be exchanged. The measuring device can transmit the data indicating the concentration of uric acid obtained by the measurement to an external device (smartphone, tablet, PC, etc.) configured as a computer through a wireless communication means (wireless communication unit) or the like. Is configured.

(Step 2)
After connecting the unit 100 and the measuring device, for example, the subject holds the measuring device and applies urine toward the intake port 33 of the unit 100. As a result, urine is supplied to the unit 100. The urine supplied to the unit 100 is taken into the storage structure from the intake 33 and is absorbed by the water absorbing member 32. The urine absorbed by the water absorbing member 32 passes through the water absorbing member 32 and reaches the surface of the sensor electrode 20. As a result, urine comes into contact with the surface of the sensor electrode 20. Excess urine that cannot be completely absorbed by the water absorbing member 32 is discharged to the outside of the storage structure (unit 100) through the discharge port 52 of the storage structure. As described above, in the present embodiment, the position and size of the discharge port 52 are set such that the discharge port 52 includes all of the sensor electrodes 20 when the unit 100 is viewed from the side. Further, when the unit 100 is viewed in a plan view, the discharge ports 52 are provided on both sides of the base material 10 in the width direction with the sensor electrode 20 interposed therebetween. As a result, the excess urine taken into the storage structure can be discharged more reliably without resorting to manual operation.

Since the wirings 13 to 15 are covered with the waterproof member 40, even if urine flows toward the wirings 13 to 15 depending on the posture of the unit 100, the urine will not be absorbed by the sheet 30 and the waterproof member. It will flow between 40 and. Therefore, urine hardly adheres to the wirings 13 to 15.

(Step 3)
When urine is in contact with the surface of the sensor electrode 20, a predetermined voltage sweep operation is performed on the sensor electrode 20 from the measuring device to electrolyze uric acid contained in urine under specific conditions. The magnitude of the electrochemical reaction (for example, redox reaction) that occurs in 1. is measured.

For example, when urine is in contact with the surface of the sensor electrode 20 (working electrode 21) and is applied while sweeping a voltage in a predetermined range between the working electrode 21 and the reference electrode 23, under certain conditions (specific voltage Uric acid is electrolyzed on the surface of the working electrode 21 (when the voltage is applied). When uric acid is electrolyzed, a current flows between the working electrode 21 and the counter electrode 22. The value of this current is measured, for example, continuously by a measuring device. The value of this electric current varies depending on the magnitude of the electrochemical reaction that occurs when uric acid is electrolyzed, and the larger the electrochemical reaction, the larger the value of the electric current.

Then, the uric acid concentration is calculated based on the maximum value (peak value) of the current values measured by the measuring device. Since the current value has a correlation with the uric acid concentration, if the relationship between the current value and the uric acid concentration is obtained in advance, the uric acid concentration can be quantified based on the measured current value. The measuring device displays the measured uric acid concentration on the display unit. The measuring device can also transmit the uric acid concentration data obtained by the measurement to an external device via a wireless communication means or the like. After the measurement of the uric acid concentration by the measuring device is completed, the subject removes (removes) the unit 100 from the measuring device and discards the unit 100.

(3) Effects According to this aspect, one or more of the following effects are exhibited.

(A) The unit 100 has a storage structure in which the peripheral portion of the sheet 30 and the base material 10 are bonded to each other, and stores urine taken in through the intake port 33 and contacts the sensor electrode 20. Further, the storage structure includes a discharge port 52 that discharges a part of the urine taken in through the intake port 33. With these structures, the amount of urine brought into contact with the sensor electrode 20 can be kept constant (predetermined amount), and the uric acid concentration can be accurately and stably measured by the unit 100.

The inventor has confirmed that the accuracy of measurement of the uric acid concentration by the unit 100 may become unstable if the amount of urine contacted with the sensor electrode 20 is not constant. The following is an experiment conducted to support this fact and its results.

This experiment was performed in a state where the sheet 30 was peeled from the unit 100 described above and the surface of the sensor electrode 20 was exposed. First, using a dropper, a predetermined amount of urine was applied (dripped) to the exposed sensor electrode 20. At this time, the amount of urine dripping (supplied) to the sensor electrode 20 was made different from high, medium, and low. In the case of “many”, each of the surface and the side surface of the sensor electrode 20 was brought into contact with urine entirely. In the case of "medium", 90% or more of the surface of the sensor electrode 20 was in contact with urine, but the rest was exposed including the side surface. In the case of “small”, about 50% of the surface of the sensor electrode 20 was in contact with urine, but the rest was exposed including the side surface. Then, cyclic voltammetry was performed in each of the cases of "high", "medium", and "low" to obtain the cyclic voltammogram shown in FIG. In addition, all the measurements were performed using the same unit 100. The measurement conditions other than the contact amount of urine (uric acid concentration in urine, sweep speed, sweep voltage range, measurement temperature, etc.) were all the same.

In FIG. 4, the solid line shows the cyclic voltammogram when the contact amount is “large”, the broken line shows the cyclic voltammogram when the contact amount is “medium”, and the dotted line shows the cyclic voltammogram when the contact amount is “small”. There is. It can be seen from FIG. 4 that although the actual uric acid concentration does not change (the actual uric acid concentration is the same), if the amount of urine contacted with the surface of the sensor electrode 20 changes, the measurement results vary. .. That is, when the amount of urine to be brought into contact with the sensor electrode 20 is not constant, it is found that the measurement accuracy of the concentration of the specific component in the test sample (for example, the uric acid concentration in urine) by the unit 100 becomes unstable.

The above experimental results show that the uric acid concentration can be measured accurately and stably by making the amount of urine brought into contact with the sensor electrode 20 constant using the outlet 52. It is a proof.

(B) When urine is poured into the unit 100 to be taken into the storage structure from the intake port 33, urine excessively taken into the storage structure is promptly (in real time) discharged using the discharge port 52. It becomes possible. As a result, it is possible to reduce stress applied to various members such as the sheet 30 that configures the storage structure, avoid deformation of the sheet 30 and peeling from the base material 10, and as a result, change in the internal volume of the storage structure. Can be suppressed. This makes it possible to more reliably obtain the above-described effect that the amount of urine to be brought into contact with the sensor electrode 20 is fixed and the measurement of the uric acid concentration by the unit 100 is performed accurately and stably.

(C) By arranging the sensor electrode 20 on the urine flow path from the inlet 33 to the outlet 52, the amount of urine that contacts the sensor electrode 20 can be reliably made constant. As a result, it becomes possible to measure the concentration of uric acid in urine more accurately and stably.

(D) The position and size of the discharge port 52 are set such that the discharge port 52 includes all of the sensor electrodes 20 when the unit 100 is viewed from the side. By providing the sensor electrode 20 on both sides in the width direction when sandwiching the sensor electrode 20 in a plan view, the excess urine taken in the storage structure is discharged without relying on an artificial operation. It becomes possible to perform surely. As a result, the amount of urine to be brought into contact with the sensor electrode 20 can be reliably kept constant, and the uric acid concentration in urine can be measured more accurately and stably.

(E) The water repellent member 31 and the water absorbing member 32 are provided on the sheet 30, and the water absorbing member 32 is provided inside the storage structure. Then, the urine absorbed by the water absorbing member 32 is brought into contact with the surface of the sensor electrode 20. As a result, urine can be reliably stored in the storage structure, and the amount of urine brought into contact with the sensor electrode 20 can be more reliably made constant. Further, by absorbing and holding urine in the water absorbing member 32, the amount of urine to be brought into contact with the sensor electrode 20 can be reliably made constant regardless of the posture of the unit 100 when measuring the uric acid concentration. .. As a result, it becomes possible to measure the uric acid concentration by the unit 100 more accurately and stably.

(F) By adhering the peripheral edge of the sheet 30 and the left end of the base material 10 to each other, the sensor electrode 20 is prevented from being exposed due to the edge of the sheet 30 being curled, and the sensitivity is lowered due to the oil stain on the sensor electrode 20. It is possible to avoid a situation such as damage.

(G) The discharge port 52 is not a check valve, but has a simple structure in which a part of the peripheral edge of the seat 30 and the base material 10 are not adhered, thereby making the unit 100 complicated, large, and high. It becomes possible to avoid cost reduction.

(4) Modifications This aspect can be modified as in the following modifications. Further, these modified examples can be arbitrarily combined.

(Modification 1)
In the above-described aspect, the example in which the peripheral portion of the sheet 30 and the base material 10 are adhered to each other via the adhesive 51 or the like has been described, but the present disclosure is not limited to such an aspect. For example, as shown in FIG. 5, the sheet 30 and the base material 10 may be bonded to each other via an adhesive 51 or the like. For example, in FIG. 5, when the up, down, left, and right directions of the paper surface are defined as the up, down, left, and right directions when the unit 100 is viewed in plan, the peripheral edge of the sheet 30 and the left side of the base material 10 (on the side where the sensor electrode 20 is provided) ) The ends may be bonded to each other via the adhesive 51 or the like, and the sheet 30 and the central part of the substrate 10 may be bonded to each other via the adhesive 51 or the like. Also according to this modification, the same effect as the above-described aspect can be obtained. Further, in this modification, since the sheet 30 and the central portion of the base material 10 are bonded to each other, the urine taken into the storage structure from the intake 33 has a convex shape depending on the posture of the unit 100. It is also possible to prevent the flow toward the portion 12 side. As a result, the adhesion of urine to the wirings 13 to 15 can be surely avoided, and the uric acid concentration can be measured more accurately and stably. In addition, it is possible to reliably avoid the infiltration of urine into the measuring instrument, and it is possible to avoid malfunction or damage of the measuring instrument.

(Modification 2)
Further, for example, the discharge port 52 may be provided on either side in the width direction of the base material 10 with the sensor electrode 20 interposed therebetween when the unit 100 is viewed in a plan view. Also in this modification, the same effect as the above-described aspect can be obtained. However, when the discharge ports 52 are provided on both sides in the width direction of the base material 10 with the sensor electrode 20 interposed therebetween, as in the above-described aspect, the discharge of the excess urine taken into the storage structure is artificially performed. It is preferable in that it can be performed more reliably without depending on the manual operation.

(Modification 3)
Further, for example, the discharge port 52 is a position facing the sensor electrode 20 when the unit 100 is viewed in a plan view, and is located on one end side (the side where the sensor electrode 20 is provided) in the longitudinal direction of the base material 10. It may be provided. That is, it may be provided at the left end of the base material 10. Also in this modification, the same effect as the above-described aspect can be obtained.

(Modification 4)
Further, for example, the discharge port 52 is provided on at least one side in the width direction of the base material 10 with the sensor electrode 20 interposed therebetween and the left end portion of the base material 10 when the unit 100 is viewed in plan. May be. Also in this modification, the same effect as the above-described aspect can be obtained.

(Modification 5)
Further, for example, the discharge port 52 may be formed by a cut provided in the sheet 30 (water repellent member 31) that forms the storage structure. The cut may be provided at a position where a part of the urine taken into the storage structure from the intake 33 can be discharged. For example, the notch can be provided in a part of the peripheral portion of the sheet 30. Further, it is preferable that the notch is provided at at least one position in the width direction of the base material 10 and/or at the left end portion of the base material 10. Also in this modification, the same effect as the above-described aspect can be obtained.

(Modification 6)
Further, for example, the discharge port 52 may be configured by providing a through hole in the base material 10. In this case, it is preferable that the through hole is provided at a position of the base material 10 where the sensor electrode 20 is not provided. Also in this modification, it is possible to obtain substantially the same effects as those of the above-described aspect.

(Modification 7)
Further, for example, the sheet 30 may not have the water absorbing member 32. That is, the sheet 30 is composed of the water-repellent member 31 having the intake port 33 opened, and the urine taken in from the intake port 33 may be configured to come into direct contact with the surface of the sensor electrode 20. Also in this modification, it is possible to obtain substantially the same effects as those of the above-described aspect. However, when the urine supplied to the unit 100 is configured to come into contact with the surface of the sensor electrode 20 through the water absorbing member 32 as in the above-described aspect, the urine that comes into contact with the surface of the sensor electrode 20 This is preferable in that the amount can be ensured to be a constant amount and the uric acid concentration in urine can be measured accurately and stably.

(Modification 8)
In the above-described embodiment, the example in which the working electrode 21 and the wiring 13 are integrally formed, the counter electrode 22 and the wiring 14 are integrally formed, and the reference electrode 23 and the wiring 15 are integrally formed has been described. The present disclosure is not limited to such an aspect. The working electrode 21 may be formed separately from the wiring 13, and the working electrode 21 and the wiring 13 may be connected via a conductive adhesive. Similarly, the counter electrode 22 may be formed separately from the wiring 14, the counter electrode 22 and the wiring 14 may be connected via a conductive adhesive, and the reference electrode 23 may be formed separately from the wiring 15. The reference electrode 23 and the wiring 15 may be electrically connected to each other.

<Other aspects of the present disclosure>
The embodiments of the present invention have been specifically described above. However, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention.

In the above-described aspect, the example in which the liquid test sample is urine collected from the subject has been described, but the present disclosure is not limited to such an aspect. For example, the liquid test sample may be body fluid such as saliva, runny nose, sweat, tears, and blood in addition to urine. Further, in the above-described aspect, an example in which the specific component contained in the test sample is uric acid has been described, but the present disclosure is not limited to such an aspect. For example, the specific component contained in the test sample may be uric acid, urine sugar, sodium, potassium, nitrite, arginine, albumin, creatinine and the like. Further, the liquid test sample is not limited to a human-derived one, and may be an animal-derived one such as a dog or a cat.

In the above-described aspect, an example has been described in which the subject supplies urine to the unit 100 by pouring urine toward the intake 33 of the unit 100, but the present invention is not limited to this. For example, the test sample is supplied to the unit 100 by immersing the side of the unit 100 on which the sensor electrode 20 is provided in a container or the like containing the test sample, and the test sample is introduced into the storage structure from the intake port 33. Good. In this case, it is preferable to use a flexible substrate as the base material 10. Thereby, the base material 10 can be easily bent. As a result, for example, even when the amount of the test sample in the container is small, the test sample can be easily taken in from the intake port 33 by bending the base material 10.

In the above-described aspect, an example in which the concentration of the specific component in the test sample is measured by the three-electrode method has been described, but the present disclosure is not limited to such an aspect. For example, the concentration of the specific component in the test sample may be measured by the two-electrode method. In this case, the sensor electrode 20 only needs to have two electrodes, a working electrode 21 and a counter electrode 22 (or a reference electrode 23).

In the above-described aspect, an example in which one sensor electrode 20 is provided on the upper surface of the base material 10 has been described, but the present disclosure is not limited to such an aspect. A plurality (two or more) of sensor electrodes 20 may be provided on the upper surface of the base material 10. In this case, it becomes possible to measure the concentrations of a plurality of types of specific components in urine. For example, it is possible to measure the uric acid concentration in urine and the concentration of a specific component (for example, urine sugar) different from uric acid in urine with one unit 100.

According to this aspect, substantially the same effect as that of the above aspect can be obtained. It should be noted that this aspect can be implemented in combination with the various aspects and modified examples described above in any form.

<Preferred embodiment of the present disclosure>
Hereinafter, a preferable aspect of the present disclosure will be additionally described.

(Appendix 1)
According to one aspect of the present disclosure,
Base material,
A sensor electrode provided on any one of the two main surfaces of the base material;
An inlet capable of taking in a liquid test sample is opened, and a sheet provided on the one surface of the base material so as to cover the sensor electrode,
A peripheral structure of the sheet and the base material are adhered to each other, and a storage structure for storing a test sample taken in through the inlet and contacting the sensor electrode is formed,
The storage structure is provided with an electrochemical sensor unit having an outlet for ejecting a part of the test sample introduced via the inlet. The discharge port functions to adjust the amount of the test sample in contact with the sensor electrode by discharging a part of the test sample.

(Appendix 2)
The sensor unit according to attachment 1, preferably,
The discharge port is configured such that a part of the peripheral portion of the sheet is not adhered to the base material.

(Appendix 3)
The sensor unit according to attachment 1 or 2, preferably,
The discharge port is formed by a cut provided in a part of the peripheral portion of the sheet.

(Appendix 4)
The sensor unit according to any one of appendices 1 to 3, preferably,
The sensor electrode is arranged on the flow path of the test sample from the intake port to the exhaust port.

(Appendix 5)
The sensor unit according to any one of appendices 1 to 4, preferably,
The outlet is provided at a position overlapping at least a part of the sensor electrode when the sensor unit is viewed from the side.

(Appendix 6)
The sensor unit according to attachment 5, preferably,
The base material has a longitudinal shape,
The discharge port is provided on at least one side in a direction orthogonal to the longitudinal direction of the base material.

(Appendix 7)
The sensor unit according to attachment 5, preferably,
The base material has a longitudinal shape,
The outlets are provided at positions on both sides in a direction orthogonal to the longitudinal direction of the base material.

(Appendix 8)
The sensor unit according to any one of appendices 5 to 8, preferably:
The base material has a longitudinal shape,
The sensor electrode is provided on one end side in the longitudinal direction of the base material,
The discharge port is provided on the one end side of the base material.

(Appendix 9)
The sensor unit according to any one of appendices 1 to 8, preferably:
The outlet has a size overlapping at least a part of the sensor electrode when the sensor unit is viewed from the side.

(Appendix 10)
The sensor unit according to any one of appendices 1 to 9, preferably,
The sheet has a water repellent member that does not absorb a test sample, and a water absorbing member that is provided so as to close the intake port and that absorbs the test sample,
The water absorbing member is arranged so as to cover at least a part of the sensor electrode,
The test sample taken in through the inlet is absorbed by the water absorbing member and permeates to the surface of the sensor electrode to bring the test sample into contact with the sensor electrode, and the test sample not absorbed by the water absorbing member is exhausted. It is configured to be discharged from the outlet.

(Appendix 11)
The sensor unit according to attachment 10, preferably,
The water absorbing member is provided on the back surface side of the water repellent member.

100 Electrochemical Sensor Unit 10 Base Material 20 Sensor Electrode 30 Sheet 33 Inlet 52 Outlet

Claims (10)

Base material,
A sensor electrode provided on any one of the two main surfaces of the base material;
An inlet capable of taking in a liquid test sample is opened, and a sheet provided on the one surface of the base material so as to cover the sensor electrode,
A peripheral structure of the sheet and the base material are adhered to each other, and a storage structure for storing a test sample taken in through the inlet and contacting the sensor electrode is formed,
The said storage structure is an electrochemical sensor unit which has an outlet which discharges a part of test sample taken in through the said inlet. The electrochemical sensor unit according to claim 1, wherein a part of the peripheral portion of the sheet is not adhered to the base material in the discharge port. The electrochemical sensor unit according to claim 1 or 2, wherein the discharge port is formed by a cut provided in a part of the peripheral portion of the sheet. The electrochemical sensor unit according to any one of claims 1 to 3, wherein the sensor electrode is arranged on a flow path of a test sample extending from the intake port to the exhaust port. The electrochemical sensor unit according to claim 1, wherein the discharge port is provided at a position overlapping at least a part of the sensor electrode when the sensor unit is viewed from the side. The base material has a longitudinal shape,
The electrochemical sensor unit according to claim 5, wherein the discharge port is provided on at least one side in a direction orthogonal to the longitudinal direction of the base material. The base material has a longitudinal shape,
The electrochemical sensor unit according to claim 5, wherein the discharge ports are provided on both sides in a direction orthogonal to the longitudinal direction of the base material. The base material has a longitudinal shape,
The sensor electrode is provided on one end side in the longitudinal direction of the base material,
The electrochemical sensor unit according to claim 5, wherein the outlet is provided on the one end side of the base material. The electrochemical sensor unit according to any one of claims 1 to 8, wherein the outlet has a size overlapping at least a part of the sensor electrode when the sensor unit is viewed from the side. The sheet has a water repellent member that does not absorb a test sample, and a water absorbing member that is provided so as to close the intake port and that absorbs the test sample,
The water absorbing member is arranged so as to cover at least a part of the sensor electrode,
The test sample taken in through the inlet is absorbed by the water absorbing member and permeates to the surface of the sensor electrode to bring the test sample into contact with the sensor electrode, and the test sample not absorbed by the water absorbing member is exhausted. The electrochemical sensor unit according to any one of claims 1 to 9, which is configured to be discharged from an outlet.

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