Electrochemical assay device

Abstract

This electrochemical assay device 1 has an inner flow passage 3 through which a liquid injected from an injection port 2 flows, and a first liquid absorbing material 4 which absorbs the liquid that has passed through the inner flow passage 3, and is configured to be capable of an electromechanical assay. The inner flow passage 3 includes: a micro flow passage 31 communicating with the injection port 2: and a separation flow passage 32 which is provided between the micro flow passage 31 and the first liquid absorbing material 4 and which when the injection of the liquid is stopped, separates the liquid inside the inner flow passage 3 so that a portion thereof remains in the micro flow passage 31 and the other portion thereof is absorbed into the first liquid absorbing material 4. The electromechanical assay device 1 has: an electrode part 51 disposed inside the micro flow passage 31; a connection part 52 connected to an external measurement device; and a conducting wire part 53 which electrically connects the electrode part 51 and the connection part 42.

Description

Technical Field

[0001] The present invention relates to an assay device, and more particularly to an electrochemical assay device that can use a trace amount of liquid and perform an assay by an electrochemical method.

Background Art

[0002] Patent Document 1 describes an example of a conventional assay device that performs an assay using a trace amount of liquid. The assay device described in Patent Document 1 includes a microchannel configured to allow a fluid to flow, an absorption porous medium disposed at a distance from one end of the microchannel located on one end side in the flow direction of the fluid, a separation space disposed between the one end of the microchannel and the absorption porous medium, and two side ventilation channels that are adjacent to both sides in the width direction orthogonal to the flow direction with respect to the microchannel so as to communicate with the microchannel and allow air to flow through.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The assay device described in Patent Document 1 detects an optical signal (such as color development or chemiluminescence) by an enzyme reaction or the like in the microchannel, and is not configured to be capable of performing an assay by an electrochemical method.

[0005] Generally, sensors and the like that utilize electrochemical methods are suitable for on-site measurement work because they enable rapid measurement, are relatively less affected by noise, and allow for miniaturization of the analyzer device. In fact, many sensor devices based on bioelectronics technology, such as semiconductor biosensors including small blood glucose sensors that measure blood glucose levels by collecting blood from fingertips like SMBG (self-monitoring of blood glucose), have been put into practical use using electrochemical methods. Therefore, it is desired that the assay device can also utilize electrochemical methods.

[0006] Therefore, an object of the present invention is to provide an electrochemical assay device that can perform an assay using a trace amount of liquid and by an electrochemical method.

Means for Solving the Problems

[0007] According to one aspect of the present invention, an electrochemical assay device has an internal flow path through which the liquid injected from the injection port flows, and a liquid absorbent that absorbs the liquid that has passed through the internal flow path, and is configured to enable an assay by an electrochemical method. The internal flow path includes a micro flow path that communicates with the injection port, and a separation flow path provided between the micro flow path and the liquid absorbent for separating the liquid in the internal flow path into a portion retained in the micro flow path and a portion absorbed by the liquid absorbent when the injection of the liquid is stopped. The internal flow path is formed by stacking an upper flow path forming member having an upper wall portion that constitutes the upper wall of the internal flow path, a lower flow path forming member having a lower wall portion that constitutes the lower wall of the internal flow path, and an intermediate member that functions as a spacer between the upper flow path forming member and the lower flow path forming member. On both sides of the micro flow path, a first lateral space communicating with the micro flow path is provided, and on both sides of the separation flow path, a second lateral space communicating with the separation flow path is provided. And, the electricity An electrode part, a connection part connected to an external measuring device, and a conducting wire part that electrically connects the electrode part and the connection part is formed on the lower flow path forming member. The electrode portion is formed at a portion of the lower flow path forming member that constitutes the lower wall of the micro flow path. The connection portion is formed at a protruding portion of the lower flow path forming member that protrudes outward of the device. The lead wire portion is formed on the lower flow path forming member so as to connect the electrode portion and the connection portion. Alternatively, an electrode portion, a connection portion connected to an external measuring device, and a lead wire portion that electrically connects the electrode portion and the connection portion are formed on the upper flow path forming member. The electrode portion is formed at a portion of the upper flow path forming member that constitutes the upper wall of the micro flow path. The connection portion is formed at a protruding portion of the upper flow path forming member that protrudes outward of the device. The lead wire portion is formed on the upper flow path forming member so as to connect the electrode portion and the connection portion. .

[0008] According to another aspect of the present invention, an electrochemical assay device has an internal flow path through which the liquid injected from the injection port flows, and a liquid absorbent that absorbs the liquid that has passed through the internal flow path, and is configured to enable an assay by an electrochemical method. The internal flow path includes a micro flow path that communicates with the injection port, and a separation flow path provided between the micro flow path and the liquid absorbent for separating the liquid in the internal flow path into a portion retained in the micro flow path and a portion absorbed by the liquid absorbent when the injection of the liquid is stopped. The internal flow path is formed by stacking an upper flow path forming member having an upper wall portion that constitutes the upper wall of the internal flow path, a lower flow path forming member having a lower wall portion that constitutes the lower wall of the internal flow path, and an intermediate member that functions as a spacer between the upper flow path forming member and the lower flow path forming member. On both sides of the micro flow path, a first lateral space communicating with the micro flow path is provided, and on both sides of the separation flow path, a second lateral space communicating with the separation flow path is provided. And, the formerA plurality of electrode portions spaced apart from each other in the flow direction of the recording liquid, a plurality of connection portions each provided spaced apart in the width direction orthogonal to the flow direction of the liquid with respect to any one of the plurality of electrode portions and connected to an external measuring device, and a plurality of conducting wire portions each electrically connecting a corresponding electrode portion and connection portion is formed on the lower channel forming member. The plurality of electrode portions are formed at a portion that constitutes the lower wall of the microchannel of the lower channel forming member. The plurality of connection portions are formed at a plurality of protruding portions of the lower channel forming member that protrude outward of the device. The plurality of lead portions are formed on the lower channel forming member so as to connect the corresponding electrode portions and connection portions. Alternatively, a plurality of electrode portions spaced apart from each other in the flow direction of the liquid, and a plurality of connection portions each provided spaced apart in the width direction orthogonal to the flow direction of the liquid with respect to any one of the plurality of electrode portions and connected to an external measuring device, and a plurality of lead portions each electrically connecting the corresponding electrode portion and connection portion are formed on the upper channel forming member. The plurality of electrode portions are formed at a portion that constitutes the upper wall of the microchannel of the upper channel forming member. The plurality of connection portions are formed at a plurality of protruding portions of the upper channel forming member that protrude outward of the device. The plurality of lead portions are formed on the upper channel forming member so as to connect the corresponding electrode portions and connection portions 。

Advantages of the Invention

[0009] According to the present invention, it is possible to provide an electrochemical assay device that can perform an assay by an electrochemical method while using a trace amount of liquid.

Brief Description of the Drawings

[0010]

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Best Mode for Carrying Out the Invention

[0011] Hereinafter, an electrochemical assay device according to an embodiment of the present invention will be described.

[0012] The electrochemical assay device according to the embodiment is configured to be able to perform an assay by an electrochemical method while using a trace amount of liquid. The electrochemical assay device may be capable of performing an assay by a method other than the electrochemical method. The liquid used in the electrochemical assay device may be any liquid that can flow through a flow path (internal flow path) in the device and is not particularly limited. Such a liquid is typically an aqueous solution.

[0013] The liquid used in the electrochemical assay device can be, for example, food, a suspension of food, an extract of food, drinking water, river water, soil suspension, industrial wastewater, or a liquid containing components collected from a living body. The liquid containing components collected from a living body can be, for example, a liquid derived from a living body such as whole blood, serum, plasma, urine, fecal dilution, saliva, or cerebrospinal fluid of a human or an animal, but is not limited thereto.

[0014] For example, when food, a suspension of food, an extract of food, drinking water, river water, soil suspension, or industrial wastewater is used, the electrochemical assay device can measure pathogens in food or drinking water, or contaminants in river water, soil, or wastewater. For example, when a liquid derived from a living body is used, the electrochemical assay device can measure diagnostically effective specimens in the liquid for applications such as pregnancy tests, urine tests, stool tests, adult disease tests, allergy tests, infectious disease tests, drug tests, and cancer tests.

[0015] As used herein, "sample" refers to a compound or composition that is mainly detected or measured using a liquid. "Samples" include, but are not limited to, saccharides (e.g., glucose), cells, proteins or peptides (e.g., serum proteins, hormones, enzymes, immunomodulatory factors, lymphokines, monokines, cytokines, glycoproteins, vaccine antigens, antibodies, growth factors, proliferation factors), fats, amino acids, nucleic acids, steroids, vitamins, pathogens or their antigens, natural or synthetic chemical substances, pollutants, therapeutic or illegal drugs, or metabolites or antibodies of these substances.

[0016] As used herein, "microchannel" refers to a channel in an assay device that enables the detection or measurement of a sample using a trace amount of liquid on the order of μl (microliters), i.e., a trace amount of liquid of 1 μl or more and less than 1000 μl.

[0017] As used herein, "assay reagent" refers to any substance that produces a detectable result by reacting with, for example, a liquid or a sample that may be contained therein. Detectable results include electrochemical signals, luminescence, fluorescence, etc. Here, in particular, when performing an assay by electrochemiluminescence, the assay reagent preferably contains an electrochemiluminescent label and a reducing agent. Examples of electrochemiluminescent labels include, but are not limited to, luminol, ruthenium (Ru) metal complexes, gold nanoparticles, adamantyldioxetane derivatives, and acridinium esters.

[0018] In this specification, the "porous body" refers to a member having a plurality (a large number) of fine pores and capable of absorbing liquid, and may include paper, a cellulose membrane, a non-woven fabric, plastic, etc. Here, although not particularly limited, the "porous body" preferably has hydrophilicity when the liquid is hydrophilic, and preferably has hydrophobicity when the liquid is hydrophobic. Preferably, the "porous body" has hydrophilicity and is paper. Further, the "porous body" can be one of cellulose, nitrocellulose, cellulose acetate, filter paper, tissue paper, toilet paper, paper towel, fabric, or a hydrophilic porous polymer that permeates water.

[0019] In the following description, the electrochemical assay device is simply referred to as the "assay device".

[0020] [First Embodiment] First, with reference to FIGS. 1 and 2, the basic configuration of the assay device according to the first embodiment will be described. FIG. 1 is a perspective view of the assay device 1 according to the first embodiment, and FIG. 2 is a schematic cross-sectional view of the assay device 1 according to the first embodiment.

[0021] As shown in FIG. 1, the assay device 1 is generally formed in a substantially rectangular parallelepiped shape and has an injection port 2 through which liquid is injected (mainly dropwise injection) on the upper surface. The injection port 2 is formed in a circular shape in a top view, and is open at one side in the longitudinal direction L on the upper surface of the assay device 1 and at a substantially central portion in the short side direction (hereinafter referred to as the "width direction") W orthogonal to the longitudinal direction L.

[0022] As shown in FIG. 2, the assay device 1 has an internal flow path 3 through which the liquid injected from the injection port 2 flows, and a first liquid absorbent 4 that absorbs the liquid that has passed through the internal flow path 3. The internal flow path 3 extends through the inside of the assay device 1 from the one side (the left side in FIG. 2) in the longitudinal direction L to the other side (the right side in FIG. 2). The first liquid absorbent 4 is formed in a block shape from a flexible porous material or the like that can absorb liquid, and is disposed on the other side in the longitudinal direction L within the assay device 1. That is, in the present embodiment, the longitudinal direction L is also the flow direction of the liquid within the assay device 1, and the one side in the longitudinal direction L where the injection port 2 is located can be referred to as the upstream side in the liquid flow direction, and the other side in the longitudinal direction L where the first liquid absorbent 4 is located can be referred to as the downstream side in the liquid flow direction.

[0023] In the present embodiment, as is also apparent from FIG. 2, the internal flow path 3 has an upper wall and a lower wall. Further, in the present embodiment, the internal flow path 3 is defined by the upper wall and the lower wall and does not have side walls. Also, the internal flow path 3 includes a micro flow path 31 and a separation flow path 32.

[0024] The micro flow path 31 constitutes the flow path on the side of the internal flow path 3 closer to the injection port 2, that is, the upstream flow path of the internal flow path 3. The micro flow path 31 communicates with the injection port 2 and is formed as a flow path that extends horizontally (it is not necessary to be strictly horizontal, and it may be generally horizontal. The same applies hereinafter) from the vicinity of the injection port 2, preferably directly below the injection port 2, to approximately the central portion in the longitudinal direction L of the assay device 1.

[0025] The separation flow path 32 constitutes the flow path on the side of the internal flow path 3 closer to the first liquid absorbent 4, that is, the downstream flow path of the internal flow path 3. The separation flow path 32 is formed as a flow path from the micro flow path 31 (the downstream end) to the first liquid absorbent 4.

[0026] That is, in the present embodiment, the first liquid absorbent 4 is provided at a distance from the micro flow path 31 (downstream end) in the longitudinal direction L, and the separation flow path 32 is provided between the micro flow path 31 and the first liquid absorbent 4.

[0027] The separation channel 32 is a channel for separating the liquid in the internal channel 3 when the injection of the liquid into the injection port 2 is stopped. Specifically, as will be described later, when the injection of the liquid into the injection port 2 is stopped, the liquid in the internal channel 3 is divided in the separation channel 32, and the liquid in the internal channel 3 is separated into a portion retained in the microchannel 31 and a portion absorbed by the first liquid absorbent 4.

[0028] Also, although not shown in FIGS. 1 and 2, as will be described later, in the assay device 1, on both sides in the width direction W of the microchannel 31, a pair of first side spaces 5, 5 are provided adjacent to the microchannel 31, and on both sides in the width direction W of the separation channel 32, a pair of second side spaces 6, 6 are provided adjacent to the separation channel 32 (see FIG. 6(a)). As described above, in the present embodiment, the internal channel 3 has no side walls. Therefore, the microchannel 31 communicates with the pair of first side spaces 5, 5, and the separation channel 32 communicates with the pair of second side spaces 6, 6.

[0029] In the present embodiment, the upper wall and the lower wall of the microchannel 31 extend horizontally. And the channel height of the microchannel 31, that is, the distance between the upper wall and the lower wall of the microchannel 31 in the height direction H is constant (it is not necessary to be exactly constant, and it may be approximately constant. The same applies hereinafter). Also, the channel height of the microchannel 31 is set so that the interfacial tension of the liquid that can prevent the leakage of the liquid into the pair of first side spaces 5, 5 when the liquid flows through the microchannel 31 can be generated.

[0030] Although not particularly limited, the channel height (dimension in the height direction H) of the microchannel 31 can be set, for example, in the range of 1 μm to 1 mm. Also, the width (dimension in the width direction W) of the microchannel 31 can be set, for example, in the range of 100 μm to 1 cm, and the length (dimension in the longitudinal direction L) of the microchannel 31 can be set, for example, in the range of 10 μm to 10 cm.

[0031] The lower wall of the separation channel 32 is configured by directly extending the lower wall of the microchannel 31 and extends horizontally. On the other hand, the upper wall of the separation channel 32 is inclined upward such that the height position increases as it moves away from the microchannel 31 (downstream end), in other words, as it approaches the first liquid absorbent 4.

[0032] Here, when the liquid is a test liquid in a biochemical test, the surface of the internal channel 3 (microchannel 31 and separation channel 32) that the liquid will contact is preferably subjected to a blocking treatment or a plasma treatment to prevent non-specific adsorption of biogenic substances, antigens, antibodies, etc. Commercially available blocking agents, bovine serum albumin, casein, skim milk, gelatin, surfactants, polyvinyl alcohol, globulin, serum (e.g., fetal bovine serum or normal rabbit serum), ethanol, MPC polymer, etc. are included in the blocking agents used for the blocking treatment. In addition, commercially available blocking agents include, but are not limited to, Immunoblock, Block Ace, Pierce Blocking Buffer, StartingBlock, StabilGuard, StabilBrock, StabilCoat, ChonBlock, etc.

[0033] Furthermore, in the present embodiment, the assay device 1 has an observation window 7 for observing the inside of the microchannel 31. The observation window 7 is formed in a rectangular shape in a top view and opens on the upper surface of the assay device 1. More specifically, the observation window 7 opens at a position above the electrode portion 51 (described later) disposed in the microchannel 31 on the upper surface of the assay device 1.

[0034] The internal channel 3 will be described in more detail.

[0035] In the present embodiment, the internal channel 3 is formed by stacking an upper channel forming member 11, a lower channel forming member 12, and an intermediate member 13 that functions as a spacer between them. Hereinafter, the upper channel forming member 11, the lower channel forming member 12, and the intermediate member 13 will be described in order.

[0036] Figure 3 shows the upper channel forming member 11. Fig. 3(a) is a top view of the upper channel forming member 11, Fig. 3(b) is a side view of the upper channel forming member 11, and Fig. 3(c) is a bottom view of the upper channel forming member 11.

[0037] In this embodiment, the upper channel forming member 11 is formed of a transparent synthetic resin so as to have flexibility. Preferably, the upper channel forming member 11 is composed of a molded product of a transparent synthetic resin. Such synthetic resins include, but are not limited to, PS (polystyrene), PMMA (acrylic), PC (polycarbonate), COP (cycloolefin polymer), COC (cycloolefin copolymer), ABS (acrylonitrile butadiene styrene), AS (acrylonitrile styrene), and silicone resin. Further, the contact angle of the surface of the upper channel forming member 11 with respect to water is preferably 90 degrees or less.

[0038] Referring to Figs. 3(a) to 3(c), the upper channel forming member 11 is formed as a flat plate member having a rectangular outer shape in a top view. In the upper channel forming member 11, a first circular hole 111 that is circular in a top view, a pair of first slit holes 112, 112 that are rectangular in a top view, and a first U-shaped hole 113 that is substantially U-shaped in a lateral direction in a top view are formed. The first circular hole 111, the pair of first slit holes 112, 112, and the first U-shaped hole 113 penetrate the upper channel forming member 11 in the height direction H.

[0039] The first circular hole 111 is formed at the one side in the longitudinal direction L of the upper channel forming member 11 and at substantially the central portion in the width direction W of the upper channel forming member 11. The first circular hole 111 constitutes a part of the injection port 2.

[0040] The pair of first slit holes 112, 112 are spaced apart from each other in the width direction W. Each of the pair of first slit holes 112, 112 extends from the vicinity of the first circular hole 111 to substantially the central portion in the longitudinal direction L of the upper channel forming member 11 toward the other side in the longitudinal direction L.

[0041] The first U-shaped hole 113 has the open part of the U facing the one side in the longitudinal direction L of the upper channel forming member 11. The first U-shaped hole 113 is formed on the other side in the longitudinal direction L of the upper channel forming member 11, above the pair of first slit holes 112, 112.

[0042] In this embodiment, the upper wall portion 117 that constitutes the upper wall of the internal flow path 3 is formed by the first slit intermediate portion 114 sandwiched between the pair of first slit holes 112, 112, the inner portion 115 inside the first U-shaped hole 113, and the first connection portion 116 that connects between the first slit intermediate portion 114 and the inner portion 115. That is, the upper channel forming member 11 has the upper wall portion 117 that constitutes the upper wall of the internal flow path 3. Further, the upper wall of the microchannel 31 is constituted by the first slit intermediate portion 114 and the first connection portion 116, and the upper wall of the separation channel 32 is constituted by the inner portion 115.

[0043] Here, in this embodiment, the width of the first slit intermediate portion 114 is constant, but the width of the inner portion 115 gradually decreases as it moves away from the first connection portion 116. Also, the distance d1 between the pair of first slit holes 112, 112 and the first U-shaped hole 113 in the longitudinal direction L is smaller than the width of the first slit intermediate portion 114. Specifically, it is set to 2 / 3 or less of the width of the first slit intermediate portion 114, preferably 1 / 2 or less of the width of the first slit intermediate portion 114.

[0044] FIG. 4 shows the lower channel forming member 12. FIG. 4(a) is a top view of the lower channel forming member 12, FIG. 4(b) is a side view of the lower channel forming member 12, and FIG. 4(c) is a bottom view of the lower channel forming member 12.

[0045] In the present embodiment, the lower channel forming member 12 is formed of a synthetic resin and has flexibility. The lower channel forming member 12 is preferably composed of a molded product of a synthetic resin colored, for example, white or black. Although not particularly limited, the lower channel forming member 12 can be formed of, for example, a PEEK material (polyether ketone resin), PE (polyethylene), PET (polyethylene terephthalate), PMMA (acrylic), PS (polystyrene), PP (polypropylene), PC (polycarbonate), ABS (acrylonitrile butadiene styrene), PVC (polyvinyl chloride), COC (cyclic olefin copolymer), or COP (cyclic olefin polymer). Further, the contact angle of the surface of the lower channel forming member 12 with respect to water is preferably 90 degrees or less.

[0046] Referring to FIGS. 4(a) to 4(c), the lower channel forming member 12 includes a flat plate-like main body portion 121 having substantially the same outer shape as that of the upper channel forming member 11 in a top view. In the main body portion 121 of the lower channel forming member 12, a pair of second slit holes 122, 122 having a rectangular shape in a top view and a pair of third slit holes 123, 123 having a rectangular shape in a top view are formed. The pair of second slit holes 122, 122 and the pair of third slit holes 123, 123 penetrate the lower channel forming member 12 in the height direction H.

[0047] The pair of second slit holes 122, 122 are formed so as to correspond to the pair of first slit holes 112, 112 of the upper channel forming member 11. That is, the pair of second slit holes 122, 122 are formed so as to be positioned below the pair of first slit holes 112, 112 of the upper channel forming member 11 when the upper channel forming member 11, the lower channel forming member 12, and the intermediate member 13 are stacked.

[0048] The pair of third slit holes 123, 123 are formed so as to correspond to the pair of straight portions of the first U-shaped hole 113 of the upper flow path forming member 11. That is, the pair of third slit holes 123, 123 are formed so as to be positioned below the pair of straight portions of the first U-shaped hole 113 of the upper flow path forming member 11 when the upper flow path forming member 11, the lower flow path forming member 12, and the intermediate member 13 are stacked.

[0049] And in the present embodiment, a lower wall portion 127 that constitutes the lower wall of the internal flow path 3 is formed by a second slit between portion 124 sandwiched between the pair of second slit holes 122, 122, a third slit between portion 125 sandwiched between the pair of third slit holes 123, 123, and a second connection portion 126 that connects between the second slit between portion 124 and the third slit between portion 125. That is, the lower flow path forming member 12 has a lower wall portion 127 that constitutes the lower wall of the internal flow path 3. Further, the lower wall of the micro flow path 31 is constituted by the second slit between portion 124 and the second connection portion 126, and the lower wall of the separation flow path 32 is constituted by the third slit between portion 125.

[0050] Here, in the present embodiment, the width of the second slit between portion 124 and the width of the third slit between portion 125 are the same as the width of the first slit between portion 114 of the upper flow path forming member 11, and the distance d2 between the pair of second slit holes 122, 122 and the pair of third slit holes 123, 123 in the longitudinal direction L is the same as the distance d1 between the pair of first slit holes 112, 112 and the first U-shaped hole 113 in the longitudinal direction L of the upper flow path forming member 11.

[0051] Further, the lower flow path forming member 12 has a protruding portion 128 that protrudes outward from the other end of the main body portion 121 in the longitudinal direction L. The protruding portion 128 is formed in a rectangular shape in a top view. In the present embodiment, the protruding portion 128 has substantially the same width as the width of the third slit between portion 125 and is located on the extension of the third slit between portion 125 in the other direction in the longitudinal direction L.

[0052] Further, an electrode portion 51, a connection portion 52, and a conductive wire portion 53 are formed in the lower channel forming member 12. Specifically, in the present embodiment, the electrode portion 51, the connection portion 52, and the conductive wire portion 53 are integrally formed in the lower channel forming member 12 by printing a conductive material on the upper surface of the lower channel forming member 12. Examples of the conductive material include, but are not limited to, conductive carbon, gold, silver, silver chloride, platinum, nickel, graphite, palladium, iron, copper, zinc, carbon paste, mesh electrodes, diamond, ITO (Indium-Tin Oxide) electrodes, and the like. Also, the electrode portion, the connection portion, and the conductive wire portion are preferably printed with the same material, but may be printed with different materials respectively.

[0053] The electrode portion 51 is formed (printed) on the upper surface of the portion 124 between the second slits that constitute the lower wall of the microchannel 31. The electrode portion 51 includes a working electrode 51a, a counter electrode 51b, and a reference electrode 51c.

[0054] The connection part 52 is formed (printed) on the upper surface of the protruding part 128. The connection part 52 includes a first terminal part 52a corresponding to the working electrode 51a, a second terminal part 52b corresponding to the counter electrode 51b, and a third terminal part 52c corresponding to the reference electrode 51c. An external measuring device, specifically, an electrochemical analyzer capable of performing electrochemical measurement, an electrochemiluminescence analyzer capable of performing electrochemiluminescence measurement, etc. are mainly connected to the connection part 52. Here, the electrochemical measurements include, but are not limited to, cyclic voltammetry, linear sweep voltammetry, staircase voltammetry, Tafel plot, chronoamperometry, chronocoulometry, differential pulse voltammetry, normal pulse voltammetry, square wave voltammetry, alternating current voltammetry, amperometry, second harmonic voltammetry, Fourier transform alternating current voltammetry, differential pulse amperometry, double differential pulse amperometry, triple pulse amperometry, integrated pulse amperometry detection, bulk electrolysis / coulometry, hydrodynamic modulation voltammetry, alternating current impedance, impedance / time, impedance / potential, chronopotentiometry, chronopotentiometry / time potentiometric stripping analysis, Electrochemical Noise Measurement, Open Circuit Potential-Time, sweep step function, multi-potential step, multi-current step, etc. Also, the electrochemiluminescence measurement here refers to a measurement method for measuring a signal that electrochemiluminesces based on the aforementioned electrochemical measurement method. As devices for measuring electrochemiluminescence, there are, but are not limited to, a cooled CCD and a photomultiplier tube, etc.

[0055] The lead portion 53 electrically connects the electrode portion 51 and the connection portion 52. The lead portion 53 is formed (printed) on the upper surface of the portion between the electrode portion 51 and the connection portion 52 in the lower flow path forming member 12 so as to connect the electrode portion 51 and the connection portion 52. In the present embodiment, the lead portion 53 is formed so as to extend from the electrode portion 51 over the upper surface of the portion between the second slit portions 124, over the upper surface of the second connection portion 126, and over the upper surface of the third slit portion 125 to reach the connection portion 52. The lead portion 53 includes a first lead portion 53a that connects the working electrode 51a and the first terminal portion 52a, a second lead portion 53b that connects the counter electrode 51b and the second terminal portion 52b, and a third lead portion 53c that connects the reference electrode 51c and the third terminal portion 52c. Here, as indicated by the dashed-dotted line in FIGS. 4(a) and (b), most of the lead portion 53 (the first to third lead portions 53a to 53c) is covered with the electrical insulating material 54. Typically, polyimide can be used as the electrical insulating material 54, but it is not limited thereto. One of the functions of the electrical insulating material 54 is to determine the area of the liquid that directly touches the electrode portion 51 in order to perform stable electrochemical measurements at the electrode portion 51 every time. In the present embodiment, the portion located between the electrode portion 51 and the connection portion 52 in the lower flow path forming member 12 is covered with the electrical insulating material 54. As a coating method, for example, when polyimide is used as the electrical insulating material 54, there is a method of immersing the lower flow path forming member 12 in a polyimide solution. In this case, the portions that are not to be coated are masked in advance. In addition to this, there are also methods of printing the polyimide solution only on the portions that require coating or directly performing contact screen printing, but it is not limited thereto.

[0056] FIG. 5 shows the intermediate member 13. FIG. 5(a) is a top view of the intermediate member 13, and FIG. 5(b) is a cross-sectional view taken along line A-A of FIG. 5(a).

[0057] Referring to FIGS. 5(a) and 5(b), the intermediate member 13 has substantially the same outer shape as that of the upper flow path forming member 11 in a top view, and is formed in a frame shape having an opening 131 inside. The dimension in the height direction H (i.e., the thickness) of the intermediate member 13 is appropriately set according to the required flow path height of the micro flow path 31. When the upper flow path forming member 11, the lower flow path forming member 12, and the intermediate member 13 are stacked, the opening 131 is formed to have a size that can enclose the first circular hole 111, the pair of first slit holes 112, 112, and the first U-shaped hole 113 of the upper flow path forming member 11 in a top view.

[0058] Also, in the present embodiment, the upper surface and the lower surface of the intermediate member 13 are formed as adhesive surfaces. As an example, the intermediate member 13 can be formed by disposing double-sided adhesive sheets on the upper surface and the lower surface of a sheet material. In this case, by appropriately selecting a sheet material having an arbitrary thickness, the dimension of the intermediate member 13 in the height direction H, and thus the flow path height of the micro flow path 31, can be freely changed.

[0059] Then, the lower surface of the upper flow path forming member 11 is joined to the upper surface of the intermediate member 13, and the upper surface of the lower flow path forming member 12 is joined to the lower surface of the intermediate member 13, so that the upper flow path forming member 11, the lower flow path forming member 12, and the intermediate member 13 are stacked and integrated. At that time, the first liquid absorbent material 4 is disposed on the other side in the longitudinal direction L within the opening 131 of the intermediate member 13.

[0060] FIG. 6 shows a structure 20 (including the first liquid absorbent material 4) in which the upper flow path forming member 11, the lower flow path forming member 12, and the intermediate member 13 are stacked and integrated. FIG. 6(a) is a perspective view of the structure 20, and FIG. 6(b) is a cross-sectional view taken along line B-B of FIG. 6(a).

[0061] As described above, in the present embodiment, the portion 114 between the first slits and the first connection portion 116 of the upper channel forming member 11 constitute the upper wall of the microchannel 31, and the portion 124 between the second slits and the second connection portion 126 of the lower channel forming member 12 constitute the lower wall of the microchannel 31. Further, an electrode portion 51 is formed on the upper surface of the portion 124 between the second slits of the lower channel forming member 12. Therefore, when the upper channel forming member 11, the lower channel forming member 12, and the intermediate member 13 are stacked and integrated, as shown in FIGS. 2 and 6(b), a microchannel 31 is formed that extends horizontally in the longitudinal direction L, has a constant channel height, and in which the electrode portion 51 is disposed. Here, the electrode portion 51 disposed in the microchannel 31 is electrically connected to the connection portion 52 via the lead wire portion 53. The lead wire portion 53 extends along the bottom of the microchannel 31 and the bottom of the separation channel 32 (i.e., the bottom inside the internal channel 3), and then further extends under the first liquid absorbent material 4.

[0062] Also, in the present embodiment, the inner portion 115 of the upper channel forming member 11 constitutes the upper wall of the separation channel 32, and the portion 125 between the third slits of the lower channel forming member 12 constitutes the lower wall of the separation channel 32. Here, as shown in FIGS. 6(a) and 6(b), when the upper channel forming member 11, the lower channel forming member 12, and the intermediate member 13 are stacked and integrated, the first liquid absorbent material 4 is disposed at the other end side in the longitudinal direction L within the opening 131 of the intermediate member 13. As a result, the tip side of the inner portion 115 of the upper channel forming member 11 abuts against the first liquid absorbent material 4. Thereby, the first liquid absorbent material 4 is deformed so as to be crushed, and the inner portion 115 of the upper channel forming member 11 is elastically deformed upward. For this reason, the separation channel 32 extends from the microchannel 31 toward the first liquid absorbent material 4, and is formed as a channel that inclines upward such that the upper wall becomes higher as it approaches the first liquid absorbent material 4 (as it moves away from the microchannel 31).

[0063] Furthermore, when the upper channel forming member 11, the lower channel forming member 12, and the intermediate member 13 are stacked and integrated, as shown in FIG. 6(a), a pair of first side spaces 5, 5 located on both sides in the width direction W of the microchannel 31 are formed, and a pair of second side spaces 6, 6 located on both sides in the width direction W of the separation channel 32 are formed. The pair of first side spaces 5, 5 are formed by a pair of first slit holes 112, 112 of the upper channel forming member 11, a pair of second slit holes 122, 122 of the lower channel forming member 12, and the opening 131 of the intermediate member 13. The pair of second side spaces 6, 6 are formed by a pair of straight portions of the first U-shaped hole 113 of the upper channel forming member 11, a pair of third slit holes 123, 123 of the lower channel forming member 12, and the opening 131 of the intermediate member 13.

[0064] Next, the configuration of the assay device 1 will be further described with reference to FIG. 7. FIG. 7 is an exploded perspective view of the assay device 1.

[0065] In addition to the above-described first liquid absorbent 4, upper channel forming member 11, lower channel forming member 12, and intermediate member 13, the assay device 1 further includes an upper housing 14, an upper cover 15, a pair of second liquid absorbents 16, 16, a third liquid absorbent 17, a lower housing 18, and a lower cover 19.

[0066] The upper housing 14 is composed of, for example, a molded product of synthetic resin. The upper housing 14 has substantially the same outer shape as the outer shape of the upper channel forming member 11 in a top view, and is attached to the upper surface of the upper channel forming member 11 using a double-sided adhesive sheet (not shown). In the upper housing 14, a second circular hole 141 having a circular shape in a top view, a first window hole 142 having a rectangular shape in a top view, and an opening hole 143 having a rectangular shape in a top view are formed. The second circular hole 141, the first window hole 142, and the opening hole 143 penetrate the upper housing 14 in the height direction H.

[0067] The second circular hole 141 is formed at a position corresponding to the first circular hole 111 of the upper flow path forming member 11. The second circular hole 141 has substantially the same size as the first circular hole 111 and, like the first circular hole 111, constitutes a part of the injection port 2.

[0068] The first window hole 142 is formed so as to be located above the electrode portion 51 of the lower flow path forming member 12. The first window hole 142 constitutes a part of the observation window 7.

[0069] The opening hole 143 is formed at a position corresponding to the first U-shaped hole 113 of the upper flow path forming member 11. The opening hole 143 has a size that can include the first U-shaped hole 113 of the upper flow path forming member 11 inside in a top view.

[0070] The upper cover 15 is constituted by, for example, a molded product of synthetic resin. The upper cover 15 is formed in a flat plate shape. The upper cover 15 has substantially the same outer shape as the outer shape of the upper housing 14 in a top view and is attached to the upper surface of the upper housing 14 using a double-sided adhesive sheet (not shown) or the like. A third circular hole 151 having a circular shape in a top view and a second window hole 152 having a rectangular shape in a top view are formed in the upper cover 15. The third circular hole 151 and the second window hole 152 penetrate the upper cover 15 in the height direction H.

[0071] The third circular hole 151 is formed at a position corresponding to the first circular hole 111 of the upper flow path forming member 11 and the second circular hole 141 of the upper housing 14. The third circular hole 151 has substantially the same size as the first circular hole 111 and the second circular hole 141 and, like the first circular hole 111 and the second circular hole 141, constitutes a part of the injection port 2. That is, in the present embodiment, the injection port 2 is formed by the first circular hole 111 of the upper flow path forming member 11, the second circular hole 141 of the upper housing 14, and the third circular hole 151 of the upper cover 15.

[0072] Similar to the first window hole 142 of the upper housing 14, the second window hole 152 is formed to be located above the electrode portion 51 of the lower channel forming member 12. The second window hole 152 has substantially the same size as the first window hole 142 and, like the first window hole 142, constitutes a part of the observation window 7. That is, in the present embodiment, the observation window 7 is formed by the first window hole 142 of the upper housing 14 and the second window hole 152 of the upper cover 15.

[0073] Similar to the first liquid absorbent 4, the pair of second liquid absorbents 16, 16 are formed of a porous material or the like capable of absorbing liquid. The pair of second liquid absorbents 16, 16 are arranged in contact with the first liquid absorbent 4 below the first liquid absorbent 4. In the present embodiment, the pair of second liquid absorbents 16, 16 are each formed in an elongated block shape and are arranged on the other side in the longitudinal direction L within the pair of third slit holes 123, 123 of the lower channel forming member 12.

[0074] Similar to the first liquid absorbent 4 and the pair of second liquid absorbents 16, 16, the third liquid absorbent 17 is formed of a porous material or the like capable of absorbing liquid. The third liquid absorbent 17 is formed in a block shape larger than the first liquid absorbent 4 and is arranged below the pair of second liquid absorbents 16, 16 in contact with the pair of second liquid absorbents 16, 16.

[0075] The lower housing 18 is composed of, for example, a molded product of synthetic resin. The lower housing 18 has substantially the same outer shape as the outer shapes of the upper channel forming member 11 and the upper housing 14 in a top view and is attached to the lower surface of the lower channel forming member 12 using a double-sided adhesive sheet (not shown) or the like. The lower housing 18 has a rectangular first accommodation hole 181 in a top view for accommodating the third liquid absorbent 17.

[0076] The lower cover 19 is composed of, for example, a molded product of synthetic resin. The lower cover 19 is formed in a flat plate shape. The lower cover 19 has substantially the same outer shape as the outer shape of the lower housing 18 in a top view and is attached to the lower surface of the lower housing 18 using a double-sided adhesive sheet (not shown) or the like.

[0077] Then, by assembling each member (component) shown in FIG. 7, the assay device 1 shown in FIGS. 1 and 2 is obtained. As described above, the obtained assay device 1 has an injection port 2 into which liquid is injected on the upper surface, an internal flow path 3 through which the liquid injected from the injection port 2 flows, and a first liquid absorbent 4 that absorbs the liquid that has passed through the internal flow path 3. The internal flow path 3 includes a micro flow path 31 communicating with the injection port 2 and a separation flow path 32 provided between the micro flow path 31 and the first liquid absorbent 4 for separating the liquid in the internal flow path 3 when the injection of the liquid is stopped.

[0078] Further, the assay device 1 has an electrode portion 51 disposed in the micro flow path 31, a connection portion 52 connected to an external measuring device, and a conducting wire portion 53 that electrically connects the electrode portion 51 and the connection portion 52. The connection portion 52 is provided on the opposite side of the electrode portion 51 with the first liquid absorbent 4 interposed therebetween in the longitudinal direction L (i.e., the liquid flow direction) and protrudes to the outside. Also, the conducting wire portion 53 extends in the internal flow path 3 from the electrode portion 51 toward the connection portion 52 in parallel with the longitudinal direction L (it is not necessary to be exactly parallel, and it is sufficient to be generally parallel. The same applies hereinafter).

[0079] Here, in the assay device 1, the assay reagent may be appropriately injected from the injection port 2 or may be disposed in advance in the micro flow path 31. When the assay reagent is disposed in the micro flow path 31, the assay reagent can be immobilized, for example, on the upper wall of the micro flow path 31, on the lower wall of the micro flow path 31, on the electrode portion 51, and / or in the vicinity of the electrode portion 51. The assay reagent to be immobilized can be, for example, an antibody, an antigen, a peptide, an electrochemically active substance, etc., but is not limited thereto.

[0080] Next, with reference to FIGS. 8 and 9, the movement of the liquid in the assay device 1 will be described.

[0081] FIG. 8 is a diagram for explaining the movement of the liquid (hereinafter referred to as "first liquid LQ1") injected into the assay device 1, and schematically shows the internal flow path 3 and the like when the assay device 1 is viewed from above. Note that FIG. 8 corresponds to a view from above of a state in which the upper flow path forming member 11 is removed from the structure 20 shown in FIGS. 6(a) and 6(b). In FIG. 8, the first liquid LQ1 is indicated by hatching.

[0082] FIG. 8(a) shows a state before the first liquid LQ1 is injected into the injection port 2. When the first liquid LQ1 is injected from the injection port 2, as shown in FIG. 8(b), the first liquid LQ1 is supplied (flows in) to the micro flow path 31. When the injection of the first liquid LQ1 is continued and an amount of the first liquid LQ1 exceeding its capacity is supplied to the micro flow path 31, the first liquid LQ1 flows into the separation flow path 32. The first liquid LQ1 that has flowed into the separation flow path 32 flows toward the first liquid absorbent 4 in the separation flow path 32 and contacts (is absorbed by) the first liquid absorbent 4. Then, a force that tries to stay in the micro flow path 31 due to surface tension and the capillary force of the first liquid absorbent 4 act on the first liquid LQ1 in the internal flow path 3, and a state in which the first liquid LQ1 is pulled between the micro flow path 31 and the first liquid absorbent 4 is formed as indicated by the arrow in FIG. 8(c). After that, when the injection of the first liquid LQ1 is stopped, as shown in FIG. 8(d), the first liquid LQ1 in the internal flow path 3 is divided in the separation flow path 32, a part of it is absorbed by the first liquid absorbent 4, and the rest remains in the micro flow path 31. That is, the first liquid LQ1 in the internal flow path 3 is separated into a part that remains in the micro flow path 31 and a part that is absorbed by the first liquid absorbent 4.

[0083] As a result, a predetermined amount of the first liquid LQ1 remains in the micro flow path 31, in other words, on the electrode portion 51. Therefore, in the assay device 1 according to the first embodiment, by connecting a measurement device related to electrochemistry, that is, the electrochemistry analyzer, the electrochemiluminescence analyzer, etc. to the connection portion 52, it is possible to stably perform an assay by an electrochemistry method on the first liquid LQ1.

[0084] FIG. 9 is a diagram for explaining the movement of the first liquid LQ1 and the second liquid LQ2 (hereinafter referred to as "second liquid LQ2") when a new liquid is injected after the injection of the first liquid LQ1 into the assay device 1, and schematically shows the internal flow path 3 and the like when the assay device 1 is viewed from above. Note that FIG. 9 is also equivalent to a view from above of a state in which the upper flow path forming member 11 is removed from the structure 20 shown in FIGS. 6(a) and 6(b), similar to FIG. 8. Further, in FIG. 9, the first liquid LQ1 is shown with the same hatching as in FIG. 8, and the second liquid LQ2 is shown with hatching different from that of the first liquid LQ1.

[0085] After the injection of the first liquid LQ1 is stopped and the second liquid LQ2 is injected, as shown in FIG. 9(a), the second liquid LQ2 is supplied to the micro flow path 31. Here, as described above, the first liquid LQ1 remains in the micro flow path 31, but the first liquid LQ1 remaining in the micro flow path 31 is pushed out of the micro flow path 31 by the newly supplied second liquid LQ2 and flows through the separation flow path 32 and is absorbed by the first liquid absorbent 4.

[0086] When the injection of the second liquid LQ2 continues and an amount of the second liquid LQ2 exceeding its capacity is supplied to the microchannel 31, in other words, an amount of the second liquid LQ2 exceeding the amount of the first liquid LQ1 retained in the microchannel 31, as shown in FIG. 9(b), the first liquid LQ1 retained in the microchannel 31 is pushed out from the microchannel 31. Then, when the second liquid LQ2 is further injected, the second liquid LQ2 flows into the separation channel 32 from the microchannel 31. The second liquid LQ2 that has flowed into the separation channel 32 flows through the separation channel 32 toward the first liquid absorbent 4 and contacts (is absorbed by) the first liquid absorbent 4. Then, a force to stay in the microchannel 31 due to surface tension and the capillary force of the first liquid absorbent 4 act on the second liquid LQ2 in the internal channel 3, and a state where the second liquid LQ2 is pulled between the microchannel 31 and the first liquid absorbent 4 is formed as indicated by the arrow in FIG. 9(c). After that, when the injection of the second liquid LQ2 is stopped, as shown in FIG. 9(d), the second liquid LQ2 in the internal channel 3 is divided in the separation channel 32, a part of which is absorbed by the first liquid absorbent 4 and the rest remains in the microchannel 31. That is, the second liquid LQ2 in the internal channel 3 is separated into the part retained in the microchannel 31 and the part absorbed by the first liquid absorbent 4.

[0087] As a result, the first liquid LQ1 in the microchannel 31 is replaced by the second liquid LQ2, and a predetermined amount of the second liquid LQ2 remains in the microchannel 31, in other words, on the electrode portion 51. Therefore, in the assay device 1 according to the first embodiment, it is possible to clean the microchannel 31 by continuously injecting, for example, distilled water as the second liquid LQ2. Further, in the assay device 1 according to the first embodiment, it is possible to easily replace the liquid in the microchannel 31 and stably perform an assay by an electrochemical method on the new liquid after replacement.

[0088] Note that the assay device 1 according to the above-described first embodiment has an observation window 7 for observing the vicinity of the electrode portion 51 in the microchannel 31. However, it is not limited to this. For example, when it is not necessary to observe the vicinity of the electrode portion 51 in the microchannel 31, the observation window 7 can be omitted. In this case, the upper channel forming member 11 does not necessarily have to be formed of a transparent synthetic resin.

[0089] Also, in the assay device 1 according to the above-described first embodiment, the electrode portion 51, the connection portion 52, and the conducting wire portion 53 are integrally formed with the lower channel forming member 12. However, it is not limited to this. The electrode portion 51, the connection portion 52, and the conducting wire portion 53 may be integrally formed with the upper channel forming member 11 instead of the lower channel forming member 12. In this case, for example, the upper channel forming member 11 is formed of a synthetic resin colored white, black, or the like, a protruding portion where the connection portion 52 is formed is provided on the upper channel forming member 11, the lower channel forming member 12 is formed of a transparent synthetic resin, and an observation window 7 for observing the vicinity of the electrode portion 51 in the microchannel 31 may be formed to open on the lower surface of the assay device 1.

[0090] Furthermore, as shown in FIG. 10, a plurality (here, three) of the assay devices 1 according to the first embodiment may be arranged side by side in the width direction and integrated to form one assay device 1'. In this way, it is convenient because assays can be performed simultaneously and in parallel for a plurality of liquids.

[0091] [Second Embodiment] FIGS. 11 to 13 show an assay device 10 according to the second embodiment. FIG. 11 is a perspective view of the assay device 10 according to the second embodiment, FIG. 12 is a cross-sectional view of the assay device 10 according to the second embodiment, and FIG. 13 is an exploded perspective view of the assay device 10 according to the second embodiment. In FIGS. 11 to 13, the same reference numerals are used for elements common to the assay device 1 according to the first embodiment. Hereinafter, mainly the configurations different from those of the assay device 1 according to the first embodiment will be described.

[0092] The main differences between the assay device 1 according to the first embodiment and the assay device 10 according to the second embodiment are as follows.

[0093] In the assay device 1 according to the first embodiment, the lower flow path forming member 12 has a protruding portion 128 that protrudes outward from the other end of the main body portion 121 in the longitudinal direction L, and a connection portion 52 is formed (printed) on the upper surface of the protruding portion 128. Therefore, in the assay device 1 according to the first embodiment, the connection portion 52 is disposed on the side opposite to the electrode portion 51 with the first liquid absorbent 4 interposed therebetween in the longitudinal direction L (i.e., the liquid flow direction), and protrudes to the outside. Further, the lead wire portion 53 extends parallel to the longitudinal direction L from the electrode portion 51 toward the connection portion 52. Specifically, the lead wire portion 53 is formed to extend from the electrode portion 51 over the upper surface of the portion between the second slits 124 of the main body portion 121, over the upper surface of the second connection portion 126, and over the upper surface of the portion between the third slits 125 to reach the connection portion 52.

[0094] On the other hand, in the assay device 10 according to the second embodiment, the lower flow path forming member 12 is provided with a protruding portion 129 that protrudes outward from the one end of the main body portion 121 in the longitudinal direction L, instead of the protruding portion 128 that protrudes outward from the other end of the main body portion 121 in the longitudinal direction L, and a connection portion 52 is formed (printed) on the upper surface of the protruding portion 129. Therefore, in the assay device 10 according to the second embodiment, the connection portion 52 is disposed on the side opposite to the electrode portion 51 with the injection port 2 interposed therebetween in the longitudinal direction L (i.e., the liquid flow direction), and protrudes to the outside. Further, the lead wire portion 53 extends parallel to the longitudinal direction L from the electrode portion 51 toward the connection portion 52. Specifically, the lead wire portion 53 is formed to extend from the electrode portion 51 over the upper surface of the one side portion of the main body portion 121 in the longitudinal direction L including the portion below the injection port 2 to reach the connection portion 52.

[0095] The other configurations of the assay device 10 according to the second embodiment are basically the same as those of the assay device 1 according to the first embodiment.

[0096] In the assay device 10 according to the second embodiment, the same effects as those of the assay device 1 according to the first embodiment can be obtained. That is, it is possible to stably perform an assay by an electrochemical method on the injected liquid, and it is also possible to clean the microchannel 31. Further, the liquid in the microchannel 31 can be easily replaced, and it is also possible to stably perform an assay by an electrochemical method on the new liquid after replacement.

[0097] In addition, the modifications applicable to the assay device 1 according to the first embodiment are also applicable to the assay device 10 according to the second embodiment. Further, as shown in FIG. 14, a plurality (here, three) of the assay devices 10 according to the second embodiment may be arranged side by side in the width direction and integrated to form one assay device 10'.

[0098] [Third Embodiment] FIGS. 15 and 16 show an assay device 100 according to the third embodiment. FIG. 15 is a perspective view of the assay device 100 according to the third embodiment, and FIG. 16 is an exploded perspective view of the assay device 100 according to the third embodiment. In FIGS. 15 and 16, the same reference numerals are used for the elements common to the assay device 1 according to the first embodiment. Hereinafter, the configurations mainly different from those of the assay device 1 according to the first embodiment will be described.

[0099] The main differences between the assay device 1 according to the first embodiment and the assay device 100 according to the third embodiment are as follows. The assay device 1 according to the first embodiment has one observation window 7, electrode portion 51, connection portion 52, and lead wire portion 53, respectively. In contrast, the assay device 100 according to the third embodiment has a plurality (here, three each) of the observation window 7, electrode portion 51, connection portion 52, and lead wire portion 53. For this reason, the lower channel forming member 12, upper housing 14, and upper cover 15 of the assay device 100 according to the third embodiment are different from those of the assay device 1 according to the first embodiment. Hereinafter, a specific description will be given.

[0100] FIG. 17 shows the lower flow path forming member 12 of the assay device 100 according to the third embodiment. FIG. 17(a) is a top view of the lower flow path forming member 12, FIG. 17(b) is a side view of the lower flow path forming member 12, and FIG. 17(c) is a bottom view of the lower flow path forming member 12.

[0101] Referring to FIGS. 17(a) to 17(c), the lower flow path forming member 12 of the assay device 100 according to the third embodiment has a main body portion 221 having substantially the same outer shape as the outer shape of the upper flow path forming member 11 in a top view. Further, in the main body portion 221 of the lower flow path forming member 12, a rectangular fourth slit hole 222, first to third rectangular holes 223 to 225, and a rectangular fifth slit hole 226 are formed in a top view. The fourth slit hole 222, the first to third rectangular holes 223 to 225, and the fifth slit hole 226 penetrate the lower flow path forming member 12 in the height direction H.

[0102] The fourth slit hole 222 is formed so as to correspond to one of the pair of first slit holes 112, 112 of the upper flow path forming member 11 and one of the pair of straight portions of the first U-shaped hole 113 of the upper flow path forming member 11. That is, the fourth slit hole 222 is formed so as to be located below one of the pair of first slit holes 112, 112 of the upper flow path forming member 11 and below one of the pair of straight portions of the first U-shaped hole 113 of the upper flow path forming member 11 when the upper flow path forming member 11, the lower flow path forming member 12, and the intermediate member 13 are stacked.

[0103] The first to third rectangular holes 223 to 225 and the fifth slit hole 226 are arranged at intervals in this order from the one side to the other side in the longitudinal direction L, and are formed so as to correspond to the other of the pair of first slit holes 112, 112 of the upper flow path forming member 11 and the other of the pair of straight portions of the first U-shaped hole 113 of the upper flow path forming member 11.

[0104] Specifically, when the upper channel forming member 11, the lower channel forming member 12, and the intermediate member 13 are stacked, the first to third rectangular holes 223 to 225 are formed so as to be located below the other of the pair of first slit holes 112, 112 of the upper channel forming member 11. The fifth slit hole 226 is formed such that when the upper channel forming member 11, the lower channel forming member 12, and the intermediate member 13 are stacked, a part of the one side in the longitudinal direction L is located below the other of the pair of first slit holes 112, 112 of the upper channel forming member 11, and most of the remainder is located below the other of the pair of straight portions of the first U-shaped hole 113 of the upper channel forming member 11.

[0105] And in the present embodiment, a lower wall portion 227 that constitutes the lower wall of the internal channel 3 is formed by a portion sandwiched between the fourth slit hole 222, the first to third rectangular holes 223 to 225, and the fifth slit hole 226. That is, the lower channel forming member 12 has a lower wall portion 227 that constitutes the lower wall of the internal channel 3.

[0106] Also, the lower wall of the microchannel 31 is constituted by a portion sandwiched between the portion on the one side in the longitudinal direction L of the fourth slit hole 222 and the part on the one side in the longitudinal direction L of the first to third rectangular holes 223 to 225 and the fifth slit hole 226, that is, the one side portion 228 which is the portion on the one side in the longitudinal direction L of the lower wall portion 227, and the lower wall of the separation channel 32 is constituted by a portion sandwiched between the portion on the other side in the longitudinal direction L of the fourth slit hole 222 and the most of the remainder of the fifth slit hole 226, that is, the other side portion 229 which is the portion on the other side in the longitudinal direction of the lower wall portion 227.

[0107] Here, the width of the lower wall portion 227 that constitutes the lower wall of the internal flow path 3 is the same as the width of the portion 114 between the first slits of the upper flow path forming member 11. Also, the dimension in the longitudinal direction L of the first inter-hole portion 230 between the first rectangular hole 223 and the second rectangular hole 224, the dimension in the longitudinal direction L of the second inter-hole portion 231 between the second rectangular hole 224 and the third rectangular hole 225, and the dimension in the longitudinal direction L of the third inter-hole portion 232 between the third rectangular hole 225 and the fifth slit hole 226 are smaller than the width of the lower wall portion 227. Specifically, they are set to be 2 / 3 or less of the width of the lower wall portion 227, preferably 1 / 2 or less of the width of the lower wall portion 227.

[0108] Also, the lower flow path forming member 12 has three protruding portions 233 that protrude outward from one end of the main body portion 221 in the width direction W. The protruding portions 233 are formed in a rectangular shape in a top view and are located laterally of one side portion 228 that constitutes the lower wall of the micro flow path 31.

[0109] Furthermore, the lower flow path forming member 12 is formed with the same number (i.e., three) of electrode portions 51, connection portions 52, and lead wire portions 53 as the protruding portions 233. The electrode portions 51, connection portions 52, and lead wire portions 53 are integrally formed on the lower flow path forming member 12 by printing the conductive material on the lower flow path forming member 12.

[0110] The three electrode portions 51 are formed at intervals in the longitudinal direction L on the upper surface of one side portion 228 that constitutes the lower wall of the micro flow path 31. Each electrode portion 51 is formed at a position corresponding to one of the three protruding portions 233 and includes a working electrode 51a, a counter electrode 51b, and a reference electrode 51c.

[0111] The three connection portions 52 are respectively formed on the upper surfaces of any one of the three protruding portions 233. Each connection portion 52 is provided at a position spaced apart in the width direction W from any one of the three electrode portions 51 and includes a first terminal portion 52a corresponding to the working electrode 51a, a second terminal portion 52b corresponding to the counter electrode 51b, and a third terminal portion 52c corresponding to the reference electrode 51c.

[0112] The three lead portions 53 are formed so as to electrically connect each of the three electrode portions 51 to the corresponding connection portion 52. In the present embodiment, the three lead portions 53 are formed to extend on the upper surface of the first inter-hole portion 230, on the upper surface of the second inter-hole portion 231, or on the upper surface of the third inter-hole portion 232 to connect to the corresponding connection portion 52 of each of the three electrode portions 51. Each lead portion 53 includes a first lead portion 53a that connects the working electrode 51a and the first terminal portion 52a, a second lead portion 53b that connects the counter electrode 51b and the second terminal portion 52b, and a third lead portion 53c that connects the reference electrode 51c and the third terminal portion 52c. Here, as indicated by the dashed-dotted line in FIGS. 17(a) and (b), most of each lead portion 53 (the first to third lead portions 53a to 53c) is covered by the electrical insulating material 54.

[0113] Also, as shown in FIG. 16, in the assay device 100 according to the third embodiment, in the upper housing 14, three first window holes 142 are formed above the three electrode portions 51 of the lower flow path forming member 12 and each of them constitutes the observation window 7. In the upper cover 15, three second window holes 152 are formed above the three electrode portions 51 of the lower flow path forming member 12 and each of them constitutes the observation window 7.

[0114] In the assay device 100 according to the third embodiment, the three electrode portions 51 are formed at intervals in the longitudinal direction L on the upper surface of one side portion 228 that constitutes the lower wall of the micro flow path 31. That is, the three electrode portions 51 are arranged in the micro flow path 31 and are provided apart from each other in the longitudinal direction L (that is, the liquid flow direction). Also, the three connection portions 52 are provided apart from each other in the width direction W orthogonal to the longitudinal direction L with respect to any one of the three electrode portions 51. Here, the three connection portions 52 are formed on the upper surfaces of three protruding portions 233 that protrude outward from the one-side end portion in the width direction W of the main body portion 221 of the lower flow path forming member 12 and protrude to the outside. And the three lead portions 53 extend in parallel with the width direction W respectively to electrically connect the corresponding electrode portion 51 and the connection portion 52.

[0115] Regarding the configurations of the assay device 100 according to the third embodiment other than the above, they are basically the same as those of the assay device 1 according to the first embodiment.

[0116] Also in the assay device 100 according to the third embodiment, the same effects as those of the assay device 1 according to the first embodiment can be obtained. Further, according to the assay device 100 according to the third embodiment, it is possible to perform an assay by an electrochemical method for a maximum of three items on the injected liquid.

[0117] Note that the assay device 100 according to the above-described third embodiment has three electrode portions 51, connection portions 52, and conductor portions 53, respectively. However, it is not limited thereto. The assay device 100 according to the third embodiment may have one electrode portion 51, connection portion 52, and conductor portion 53, respectively, two of each, or four or more of each, similar to the assay device 1 according to the first embodiment and the assay device 10 according to the second embodiment. Also, the modifications applicable to the assay device 1 according to the first embodiment are also applicable to the assay device 100 according to the third embodiment. Further, as shown in FIG. 18, two assay devices 100 according to the third embodiment in which the arrangements of the connection portions 52 are opposite to each other may be arranged side by side in the width direction and integrated into one assay device 100'.

[0118] [Fourth Embodiment] FIGS. 19 to 21 show an assay device 200 according to the fourth embodiment. FIG. 19 is a perspective view of the assay device 200 according to the fourth embodiment, FIG. 20 is a cross-sectional view of the assay device 200 according to the fourth embodiment, and FIG. 21 is an exploded perspective view of the assay device 200 according to the fourth embodiment. In FIGS. 19 to 21, the same reference numerals are used for the elements common to the assay device 1 according to the first embodiment. Hereinafter, the configurations mainly different from those of the assay device 1 according to the first embodiment will be described.

[0119] The main differences between the assay device 1 according to the first embodiment and the assay device 200 according to the fourth embodiment are as follows. In the assay device 200 according to the fourth embodiment, a pair of second liquid absorbents 16, 16 and the lower housing 18 are omitted from the assay device 1 according to the first embodiment, and instead, a second upper housing 201 and a spacer member 202 are provided (see FIGS. 7 and 21). Further, the upper flow path forming member 11, the lower flow path forming member 12, the third liquid absorbent 17, and the lower cover 19 of the assay device 200 according to the fourth embodiment are different in shape from those of the assay device 1 according to the first embodiment. Hereinafter, the second upper housing 201, the third liquid absorbent 17, the upper flow path forming member 11, the lower flow path forming member 12, the spacer member 202, and the lower cover 19 will be described in this order.

[0120] The second upper housing 201 is disposed between the upper cover 15 and the upper housing 14. The outer shape of the second upper housing 201 in a top view is substantially the same as that of the upper housing 14. However, the dimension of the second upper housing 201 in the height direction H is larger than that of the upper housing 14. In the second upper housing 201, a fourth circular hole 2011 and a third window hole 2012 corresponding to the second circular hole 141 and the first window hole 142 of the upper housing 14 are formed. The fourth circular hole 2011 and the third window hole 2012 penetrate the second upper housing 201 in the height direction H. The fourth circular hole 2011 constitutes a part of the injection port 2, and the third window hole 2012 constitutes a part of the observation window 7.

[0121] Further, a second upper housing 201 is formed with a second accommodation hole 2013. The second accommodation hole 2013 is provided at a position corresponding to the opening hole 143 of the upper housing 14 and penetrates the second upper housing 201 in the height direction H. The second accommodation hole 2013 of the second upper housing 201 corresponds to the first accommodation hole 181 provided in the lower housing 18 of the assay device 1 according to the first embodiment for accommodating the third liquid absorbent 17. The second upper housing 201 is composed of, for example, a molded product of synthetic resin and is attached to the upper surface of the upper housing 14 and the lower surface of the upper cover 15 using a double-sided adhesive sheet (not shown).

[0122] In the assay device 200 according to the fourth embodiment, the third liquid absorbent 17 has a protruding portion 17a that protrudes downward on the other side in the longitudinal direction L. The third liquid absorbent 17 is accommodated in the second accommodation hole 2013 of the second upper housing 201 in a state where the protruding portion 17a is in contact with the upper surface of the first liquid absorbent 4. That is, in the assay device 200 according to the fourth embodiment, the third liquid absorbent 17 is disposed above the first liquid absorbent 4.

[0123] In the assay device 200 according to the fourth embodiment, the upper flow path forming member 11 is formed with a first circular hole 111 and a second U-shaped hole 2014 that is substantially U-shaped in a lateral direction in a top view. The second U-shaped hole 2014 is formed on the other side in the longitudinal direction L of the upper flow path forming member 11 above the first circular hole 111, and the open portion of the U-shape faces the one side in the longitudinal direction L of the upper flow path forming member 11. The second U-shaped hole 2014 has a shape that combines the pair of first slit holes 112, 112 and the first U-shaped hole 113 of the upper flow path forming member 11 of the assay device 1 according to the first embodiment. That is, the second U-shaped hole 2014 penetrates the upper flow path forming member 11 in the height direction H. And in the assay device 200 according to the fourth embodiment, an upper wall portion 117 that constitutes the upper wall of the internal flow path 3 is formed by a portion inside the second U-shaped hole 2014 in the upper flow path forming member 11.

[0124] The upper wall portion 117 has, in order from the one side in the longitudinal direction L, that is, the side closer to the first circular hole 111 (inlet 2), a first straight portion 117a, a narrow-width portion 117b, and a second straight portion 117c.

[0125] The first straight portion 117a extends linearly from the first circular hole 111 (inlet 2) toward the other side in the longitudinal direction L. The width of the first straight portion 117a is smaller than the diameter of the first circular hole 111 (inlet 2) and is constant. The narrow-width portion 117b is a portion where the width of the upper wall portion 117 becomes narrow. The narrow-width portion 117b is provided between the first straight portion 117a and the second straight portion 117c and connects the two. In the present embodiment, the narrow-width portion 117b is formed in a tapered shape in which its width gradually narrows from the width of the first straight portion 117a toward the other side in the longitudinal direction L. The second straight portion 117c extends linearly from the narrow-width portion 117b toward the other side in the longitudinal direction L. The width of the second straight portion 117c is smaller than the width of the first straight portion 117a and is constant. The narrow-width portion 117b only needs to be a portion where the width of the upper wall portion 117 becomes narrow, and is not limited to the tapered shape. For example, the narrow-width portion 117b may be formed in a stepped shape that changes in one step or multiple steps from the width of the first straight portion 117a to the width of the second straight portion 117c.

[0126] In the assay device 200 according to the fourth embodiment, a pair of sixth slit holes 2015, 2015 are formed in the main body portion 121 of the lower flow path forming member 12. The pair of sixth slit holes 2015, 2015 are formed so as to be located below the pair of straight portions of the second U-shaped hole 2014 of the upper flow path forming member 11 when the upper flow path forming member 11, the lower flow path forming member 12, and the intermediate member 13 are stacked. And in the assay device 200 according to the fourth embodiment, a lower wall portion 127 that constitutes the lower wall of the internal flow path 3 is formed by the portion sandwiched between the pair of sixth slit holes 2015, 2015 in the lower flow path forming member 12. Further, the electrode portion 51 and the lead wire portion 53 are formed on the upper surface of the portion sandwiched between the pair of sixth slit holes 2015, 2015, and the connection portion 52 is formed on the upper surface of the protruding portion 128.

[0127] The spacer member 202 is disposed between the lower flow path forming member 12 and the lower cover 19. The outer shape of the spacer member 202 in a top view is substantially the same as that of the main body portion 121 of the lower flow path forming member 12. Further, a pair of seventh slit holes 2016, 2016 corresponding to the pair of sixth slit holes 2015, 2015 of the lower flow path forming member 12 are formed in the spacer member 202. The dimension of the spacer member 202 in the height direction H can be arbitrarily set. That is, the dimension of the spacer member 202 in the height direction H may be the same as or different from that of the main body portion 121 of the lower flow path forming member 12. The spacer member 202 is composed of, for example, a molded product of synthetic resin, and is attached to the lower surface of the lower flow path forming member 12 using a double-sided adhesive sheet (not shown). When the dimension of the spacer member 202 in the height direction H is the same as that of the main body portion 121 of the lower flow path forming member 12, the component that becomes the main body portion 121 of the lower flow path forming member 12 can be used as the spacer member 202.

[0128] In the assay device 200 according to the fourth embodiment, a pair of slit grooves 2017, 2017 corresponding to the pair of sixth slit holes 2015, 2015 of the lower flow path forming member 12 and the pair of seventh slit holes 2016, 2016 of the spacer member 202 are formed in the lower cover 19. In the assay device 200 according to the fourth embodiment, the lower cover 19 is attached to the lower surface of the spacer member 202 using a double-sided adhesive sheet (not shown). Note that the pair of slit grooves 2017, 2017 may be a pair of slit holes.

[0129] In the assay device 200 according to the fourth embodiment, the upper wall of the microchannel 31 is formed by the first straight portion 117a and the narrow portion 117b of the upper wall portion 117, and the upper wall of the separation channel 32 is formed by the second straight portion 117c of the upper wall portion 117. Also, the lower wall of the microchannel 31 is formed by the portion of the lower wall portion 127 corresponding to the first straight portion 117a and the narrow portion 117b of the upper wall portion 117, and the lower wall of the separation channel 32 is formed by the portion of the lower wall portion 127 corresponding to the second straight portion 117c of the upper wall portion 117. Further, a pair of first lateral spaces 5, 5 and a pair of second lateral spaces 6, 6 are formed by a pair of straight portions of the second U-shaped hole 2014 of the upper channel forming member 11, a pair of sixth slit holes 2015, 2015 of the lower channel forming member 12, a pair of seventh slit holes 2016, 2016 of the spacer member 202, and a pair of slit grooves 2017, 2017 of the lower cover 19.

[0130] Regarding the configurations of the assay device 200 according to the fourth embodiment other than the above, they are basically the same as those of the assay device 1 according to the first embodiment.

[0131] In the assay device 200 according to the fourth embodiment, the same effects as those of the assay device 1 according to the first embodiment can be obtained. In the assay device 200 according to the fourth embodiment, it is also possible to omit the spacer member 202 by appropriately adjusting the dimension in the height direction H of the lower channel forming member 12 and / or the dimension in the height direction of the lower cover 19. Also, the modifications applicable to the assay device 1 according to the first embodiment are also applicable to the assay device 200 according to the fourth embodiment. Further, although not shown, a plurality of assay devices 200 according to the fourth embodiment may be arranged side by side in the width direction and integrated into one assay device.

[0132] [Fifth Embodiment] Figs. 22 to 24 show the assay device 210 according to the fifth embodiment. Fig. 22 is a perspective view of the assay device 210 according to the fifth embodiment, Fig. 23 is a cross-sectional view of the assay device 210 according to the fifth embodiment, and Fig. 24 is an exploded perspective view of the assay device 210 according to the fifth embodiment. Hereinafter, mainly the configuration different from the assay device 200 according to the fourth embodiment will be described.

[0133] The main difference between the assay device 200 according to the fourth embodiment and the assay device 210 according to the fifth embodiment is that in the assay device 210 according to the fifth embodiment, instead of the second upper housing 201 and the upper cover 15 of the assay device 200 according to the fourth embodiment, an absorbent housing 211 for accommodating the third liquid absorbent 17 and its cover member 212 are provided (see Figs. 21 and 24).

[0134] The absorbent housing 211 is formed in a rectangular shape in a top view. The dimension of the absorbent housing 211 in the longitudinal direction L is not particularly limited, but can be about 1 / 2 of that of the upper housing 14. The dimension of the absorbent housing 211 in the width direction is substantially equal to that of the upper housing 14, and the dimension of the absorbent housing 211 in the height direction is larger than that of the upper housing 14. In the absorbent housing 211, a third accommodation hole 2111 corresponding to the second accommodation hole 2013 of the second upper housing 201 of the assay device 200 according to the fourth embodiment is formed. That is, in the assay device 210 according to the fifth embodiment, the third liquid absorbent 17 is accommodated in the third accommodation hole 2111 of the absorbent housing 211 with the protruding portion 17a in contact with the upper surface of the first liquid absorbent 4. The absorbent housing 211 is composed of, for example, a molded product of a synthetic resin, and is attached to the upper housing 14 using a double-sided adhesive sheet (not shown) so that the third accommodation hole 2111 is located above the opening hole 143 of the upper housing 14.

[0135] The cover member 212 is composed of, for example, a molded product of synthetic resin. The cover member 212 is formed in a flat plate shape and has substantially the same outer shape as the outer shape of the housing 211 for the absorbent material in a top view. The cover member 212 is attached to the upper surface of the housing 211 for the absorbent material so as to cover the third accommodation hole 2111 by using a double-sided adhesive sheet (not shown) or the like.

[0136] Regarding the other configurations of the assay device 210 according to the fifth embodiment, they are basically the same as those of the assay device 200 according to the fourth embodiment.

[0137] Also in the assay device 210 according to the fifth embodiment, the same effects as those of the assay device 200 according to the fourth embodiment can be obtained, and further, the same effects as those of the assay device 1 according to the first embodiment can be obtained. Note that the modifications applicable to the assay device 1 according to the first embodiment and / or the assay device 200 according to the fourth embodiment are also applicable to the assay device 210 according to the fifth embodiment. Although not shown, a plurality of assay devices 210 according to the fifth embodiment may be arranged side by side in the width direction and integrated into one assay device.

[0138] As described above, the embodiments of the present invention and their modified examples have been described. However, the present invention is not limited to the above-described embodiments, and it goes without saying that modifications and changes can be made based on the technical idea of the present invention.

Example

[0139] [Example 1] In Example 1, the assay device according to the embodiment was connected to a potentiostat, and measurements were performed on K3[Fe(CN)6] (potassium ferricyanide) solution by cyclic voltammetry. When K3[Fe(CN)6] solution was dripped into the inlet 2, a current value associated with an oxidation-reduction reaction was observed. After that, when a solvent not containing K3[Fe(CN)6] solution was dripped into the inlet 2 instead of the K3[Fe(CN)6] solution, the characteristic peak current of the K3[Fe(CN)6] solution was no longer observed. From these results, it was confirmed that the assay device according to the embodiment can perform an assay by cyclic voltammetry, and that the liquid in the assay device can be replaced and left to stand.

[0140] [Example 2] In Example 2, the assay device according to the embodiment was incorporated into an electrochemiluminescence measuring device, and electrochemiluminescence of luminol was measured by cyclic voltammetry. Luminol was oxidized on the electrode surface at around 0.2 to 0.3 V to become radicals and diazoquinone, and the oxidized luminol (radicals and diazoquinone) was converted to reactive oxygen species (H2O2 and O2) generated by electrochemical reduction reaction from dissolved oxygen by applying a negative charge (-0.5 to -1.0 V). - ) and emits light. Here, the antioxidant level (antioxidant effect) of apple juice, orange juice, grape juice, and tomato juice was measured by taking advantage of the competitive reaction between luminol and antioxidants caused by reactive oxygen species. It was confirmed that the antioxidant level could be measured for each type of juice.

[0141] [Example 3] In Example 3, the assay device according to the embodiment was incorporated into an electrochemiluminescence measurement device, and the electrochemiluminescence of luminol using gold nanoparticles was measured. Specifically, in Example 3, a 10 mM luminol solution was adjusted to a 0.2 mM luminol solution with a Tris-HCl buffer (pH 8, 200 mM), and a gold nanoparticle solution and a Tris-HCl buffer (pH 8, 200 mM) were mixed at a ratio of 1:4, and a mixture of these at a ratio of 1:1 was used. As a result, it was confirmed that the electrochemiluminescence of luminol could be measured without problems. In this case, since the gold nanoparticles in the Tris-HCl buffer react with dissolved oxygen to generate reactive oxygen species, unlike Example 2, the generation of reactive oxygen species by an electrochemical reaction is not necessary.

Explanation of symbols

[0142] 1, 1´, 10, 10´, 100, 100´, 200, 210… assay device, 2… injection port, 3… internal flow path, 4… first liquid absorbent, 11… upper flow path forming member, 12… lower flow path forming member, 13… intermediate member, 31… micro flow path, 32… separation flow path, 51… electrode part, 52… connection part, 53… conductor part, 54… electrical insulating material, 117… upper wall part, 127, 227… lower wall part, LQ1… first liquid, LQ2… second liquid

Claims

1. An electrochemical assay device having an internal flow path through which a liquid injected from an injection port flows and a liquid absorbent that absorbs the liquid that has passed through the internal flow path, and configured to enable an assay by an electrochemical method, wherein the internal flow path includes a micro flow path communicating with the injection port and a separation flow path provided between the micro flow path and the liquid absorbent for separating the liquid in the internal flow path into a portion retained in the micro flow path and a portion absorbed by the liquid absorbent when the injection of the liquid is stopped, wherein the internal flow path is formed by stacking an upper flow path forming member having an upper wall portion constituting an upper wall of the internal flow path, a lower flow path forming member having a lower wall portion constituting a lower wall of the internal flow path, and an intermediate member functioning as a spacer between the upper flow path forming member and the lower flow path forming member, wherein first lateral spaces communicating with the micro flow path are provided on both sides of the micro flow path, and second lateral spaces communicating with the separation flow path are provided on both sides of the separation flow path, wherein an electrode portion, a connection portion connected to an external measuring device, and a conductor portion electrically connecting the electrode portion and the connection portion are formed on the lower flow path forming member, wherein the electrode portion is formed at a site constituting a lower wall of the micro flow path of the lower flow path forming member, the connection portion is formed at a protruding portion of the lower flow path forming member protruding outward of the device, and the conductor portion is formed on the lower flow path forming member so as to connect the electrode portion and the connection portion, An electrochemical assay device.

2. An electrochemical assay device having an internal flow path through which a liquid injected from an injection port flows and a liquid absorbent that absorbs the liquid that has passed through the internal flow path, and configured to enable an assay by an electrochemical method, wherein the internal flow path includes a micro flow path communicating with the injection port and a separation flow path provided between the micro flow path and the liquid absorbent for separating the liquid in the internal flow path into a portion retained in the micro flow path and a portion absorbed by the liquid absorbent when the injection of the liquid is stopped, wherein the internal flow path is formed by stacking an upper flow path forming member having an upper wall portion constituting an upper wall of the internal flow path, a lower flow path forming member having a lower wall portion constituting a lower wall of the internal flow path, and an intermediate member functioning as a spacer between the upper flow path forming member and the lower flow path forming member, On both sides of the microchannel, a first lateral space communicating with the microchannel is provided, and on both sides of the separation channel, a second lateral space communicating with the separation channel is provided. An electrode portion, a connection portion connected to an external measuring device, and a conducting wire portion electrically connecting the electrode portion and the connection portion are formed on the upper flow path forming member. The electrode portion is formed at a portion constituting the upper wall of the microchannel of the upper flow path forming member, the connection portion is formed at a protruding portion of the upper flow path forming member protruding outward of the device, and the conducting wire portion is formed on the upper flow path forming member so as to connect the electrode portion and the connection portion. Electrochemical assay device.

3. The electrochemical assay device according to claim 1 or 2, wherein the electrode portion, the connection portion, and the conducting wire portion are formed by printing a conductive material on the lower flow path forming member or on the upper flow path forming member.

4. The electrode portion includes a working electrode, a counter electrode, and a reference electrode. It has an observation window that opens to the outside of the device and observes the vicinity of the electrode portion from the outside. The electrochemical assay device according to claim 1 or 2.

5. The electrochemical assay device according to claim 1 or 2, wherein the connection portion is provided on the side opposite to the electrode portion with the liquid absorbent interposed therebetween in the liquid flow direction.

6. The electrochemical assay device according to claim 1 or 2, wherein the connection portion is provided on the side opposite to the electrode portion with the injection port interposed therebetween in the liquid flow direction.

7. The electrochemical assay device according to claim 1 or 2, wherein the connection portion is provided at a distance from the electrode portion in the width direction orthogonal to the liquid flow direction.

8. An electrochemical assay device having an internal flow path through which a liquid injected from an injection port flows and a liquid absorbent that absorbs the liquid that has passed through the internal flow path, and configured to be capable of assay by an electrochemical method. The internal flow path includes a microchannel communicating with the injection port and a separation channel provided between the microchannel and the liquid absorbent for separating the liquid in the internal flow path into a portion retained in the microchannel and a portion absorbed by the liquid absorbent when the injection of the liquid is stopped. The internal flow path is formed by stacking an upper flow path forming member having an upper wall portion that constitutes the upper wall of the internal flow path, a lower flow path forming member having a lower wall portion that constitutes the lower wall of the internal flow path, and an intermediate member that functions as a spacer between the upper flow path forming member and the lower flow path forming member. On both sides of the micro flow path, a first lateral space communicating with the micro flow path is provided, and on both sides of the separation flow path, a second lateral space communicating with the separation flow path is provided. A plurality of electrode portions spaced apart from each other in the flow direction of the liquid, a plurality of connection portions each provided spaced apart in the width direction orthogonal to the flow direction of the liquid with respect to any one of the plurality of electrode portions and connected to an external measuring device, and a plurality of conducting wire portions each electrically connecting a corresponding electrode portion and connection portion are formed on the lower flow path forming member. The plurality of electrode portions are formed at a portion of the lower flow path forming member that constitutes the lower wall of the micro flow path, the plurality of connection portions are formed at a plurality of protruding portions of the lower flow path forming member that protrude outward of the device, and the plurality of conducting wire portions are formed on the lower flow path forming member so as to connect the corresponding electrode portion and connection portion. Electrochemical assay device. **Claim 9**: An electrochemical assay device having an internal flow path through which a liquid injected from an injection port flows and a liquid absorbent that absorbs the liquid that has passed through the internal flow path, and configured to enable an assay by an electrochemical method. The internal flow path includes a micro flow path communicating with the injection port and a separation flow path provided between the micro flow path and the liquid absorbent for separating the liquid in the internal flow path into a portion retained in the micro flow path and a portion absorbed by the liquid absorbent when the injection of the liquid is stopped. The internal flow path is formed by stacking an upper flow path forming member having an upper wall portion that constitutes the upper wall of the internal flow path, a lower flow path forming member having a lower wall portion that constitutes the lower wall of the internal flow path, and an intermediate member that functions as a spacer between the upper flow path forming member and the lower flow path forming member. On both sides of the micro flow path, a first lateral space communicating with the micro flow path is provided, and on both sides of the separation flow path, a second lateral space communicating with the separation flow path is provided. A plurality of electrode portions spaced apart from each other in the flow direction of the liquid, a plurality of connection portions each provided spaced apart in the width direction orthogonal to the flow direction of the liquid with respect to any one of the plurality of electrode portions and connected to an external measuring device, and a plurality of wire portions each electrically connecting a corresponding electrode portion and connection portion are formed in the upper flow path forming member, The plurality of electrode portions are formed at portions constituting the upper wall of the micro flow path of the upper flow path forming member, the plurality of connection portions are formed at a plurality of protruding portions of the upper flow path forming member protruding outward of the device, and the plurality of wire portions are formed in the upper flow path forming member so as to connect the corresponding electrode portions and connection portions, Electrochemical assay device.

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