Flow path device

Abstract

The present invention addresses the problem such that, with respect to measurement using a flow channel device, it takes a long time to detect and quantify an analyte due to a low flow rate. In order to solve this problem, provided is a flow channel device for analyzing an analyte, the flow channel device having a flow channel region surrounded by a flow channel wall provided inside a porous substrate. The flow channel region includes: an addition section through which a liquid is added; a ligand section in which a ligand is provided; an absorption section into which the liquid flows; and a connection section for connecting any two selected from the group consisting of the addition section, the ligand section, and the absorption section. The ligand is a substance that specifically binds to the analyte. At least a portion of the inner wall of the flow channel wall has adhered thereto any selected from the group consisting of albumin, PEG, PVP, a PEG block copolymer, a PVP block copolymer, and a surfactant having a PEG chain.

Description

Fluid flow devices

[0001] This disclosure relates to a fluidic device.

[0002] Technologies have been developed to detect and quantify target substances in samples, such as immunoassays that utilize antibody-antigen reactions. Among these, immunochromatography is used as a simple method for testing target substances because it allows for rapid measurement with simple operation. A typical immunochromatographic test is as follows: A first site is formed on a chromatographic medium (e.g., a strip of nitrocellulose membrane) where a detection ligand labeled with colored particles is placed, and a second site is formed where a capture ligand for the target substance is immobilized on the medium. A liquid sample containing the target substance is supplied to the first site to react with the target substance and the detection ligand to form a complex. Then, using capillary action, the complex is moved to the second site, where a capture ligand-target substance-detection ligand complex is formed. The presence or amount of the target substance is measured based on the presence or absence or intensity of the signal of the labeled substance in the second site. In immunochromatography, it is customary to block the chromatographic medium to minimize nonspecific binding of antigens and antibodies.

[0003] In recent years, paper channel devices have attracted attention. Paper channel devices utilize inexpensive porous materials such as paper or cloth, and can drive samples using capillary action, similar to immunochromatography, thus enabling low-cost use. They are also easily portable, highly disposable, and can be used in non-electrical environments. Furthermore, they allow for the easy formation of microchannel patterns within the substrate, enabling the integration of a series of operations such as sample pretreatment, stirring, mixing, reaction, and detection. This allows for miniaturization of the testing system, rapid analysis, and reduction of samples, reagents, and waste liquids. Moreover, paper channel devices are disposable and require no external equipment, thus eliminating the need for device maintenance. Therefore, using paper channel devices makes it possible for anyone, anywhere, to easily and inexpensively perform point-of-care (POC) diagnostics.

[0004] Patent Document 1 proposes a paper microfluidic device using a nitrocellulose membrane as a substrate. A channel wall made of thermoplastic resin is formed on a nitrocellulose membrane blocked with albumin using a thermal transfer printer.

[0005] Patent Document 2 proposes a three-dimensional microfluidic device assembled from three parts: an upper part, an intermediate part, and a lower part. The upper part has a capture ligand fixed to it, the intermediate part connects the upper and lower parts and has a detection ligand installed, and the lower part divides the sample introduced from the inlet into multiple microfluidic pathways for flow. The walls of these pathways are formed by impregnation and curing with a photocurable resin. Only the lower part is blocked with bovine serum albumin.

[0006] Non-patent document 1 proposes a paper microfluidic device using a nitrocellulose membrane as a substrate. In this device, a solution containing acrylic resin is ejected onto the nitrocellulose membrane using an inkjet printer along a channel wall pattern to form channel walls, and then the device is blocked with casein to fabricate a paper microfluidic device for immunoassay.

[0007] Japanese Patent No. 6657556, International Publication No. 2012 / 105721

[0008] Lab Chip, 2013, 13, 126-135

[0009] Conventional technology had room for improvement regarding the flow velocity of the liquid flowing through the channels of fluidic devices used for analyzing test substances.

[0010] This disclosure provides a flow channel device for analyzing a test substance, having a flow channel region surrounded by a flow channel wall provided inside a porous substrate, wherein the flow channel region includes an addition section for adding liquid, a ligand section provided with a ligand, an absorption section into which the liquid flows, a connecting section connecting any two selected from the group consisting of the addition section, the ligand section, and the absorption section, the ligand being a substance that specifically binds to the test substance, and at least a portion of the inner wall of the flow channel wall having one of the group consisting of albumin, PEG, PVP, PEG block copolymer, PVP block copolymer, and a surfactant having a PEG chain attached to it.

[0011] An example of a flow channel device according to the first embodiment (top view) is shown. An example of a flow channel device according to the first embodiment (cross-sectional view) is shown. An example of a flow channel device according to the first embodiment (cross-sectional view) is shown. An example of a flow channel device according to the first embodiment (cross-sectional view) is shown. An example of a flow channel device according to the second embodiment (top view) is shown. An example of a flow channel device according to the third embodiment (top view) is shown. An example of a flow channel device according to the fourth embodiment (top view) is shown. An example of a flow channel device according to the fifth embodiment (top view) is shown. An example of a flow channel device before various ligands are placed (top view) is shown. An example of a flow channel device according to the seventh embodiment (top view) is shown. An example of a flow channel device according to the eighth embodiment (top view) is shown. An example of a flow channel device according to the eighth embodiment (each component) is shown. An example of a flow channel device according to the eighth embodiment (cross-sectional view) is shown. An example of a flow channel device according to the ninth embodiment (top view) is shown. An example of a flow channel device according to the ninth embodiment (each component) is shown. An example of a flow channel device according to the tenth embodiment (top view) is shown. An example of a flow channel device according to the tenth embodiment (cross-sectional view) is shown. An example of a flow channel device according to the eleventh embodiment (top view) is shown. An example of a flow channel device according to the eleventh embodiment (cross-sectional view) is shown. An example of a flow channel device according to Example 12 (top view) is shown. An example of a flow channel device according to Example 13 (top view) is shown.

[0012] (Problems with the prior art) In flow channels such as those described in Patent Documents 1 and 2, the entire or partial flow channel is surrounded by hydrophobic flow channel walls, which creates resistance between the flow channel walls and the sample, slowing down the sample flow velocity. In contrast, in flow channels like that described in Non-Patent Document 1, the substrate and flow channel walls are blocked by casein, which is poorly soluble in water under neutral conditions, resulting in resistance due to the hydrophobic flow channel walls and slowing down the sample flow velocity. In typical immunochromatographic flow channels cut into strips, there are no flow channel walls, and the flow channel is surrounded by hydrophobic air, resulting in resistance at the sample-air interface and slowing down the sample flow velocity. In other words, these flow channels have the problem that the slow flow velocity of the sample requires a lot of time to detect or quantify the target substance, thus impairing the speed of the test.

[0013] In a typical immunochromatograph with a flow channel, increasing the sample flow rate requires increasing the pore size and porosity of the chromatographic medium. However, as the medium becomes coarser, the intensity and accuracy of signals such as color development tend to decrease. On the other hand, in a paper flow channel device, hydrophilizing the flow channel wall surrounding the channel reduces resistance at the interface between the flow channel wall and the sample, thereby improving the flow rate. The inventors focused on providing hydrophilic groups or hydrophilic substances on the inner wall of the flow channel in a paper flow channel device, leading to this disclosure.

[0014] In other words, the present disclosure provides a flow channel device for analyzing a test substance, as a first embodiment, having a flow channel region surrounded by a flow channel wall provided inside a porous substrate, wherein the flow channel region includes an addition section for adding liquid, a ligand section provided with a ligand, an absorption section into which the liquid flows, a connecting section connecting any two selected from the group consisting of the addition section, the ligand section, and the absorption section, the ligand being a substance that specifically binds to the test substance, and at least a portion of the inner wall of the flow channel wall having one selected from the group consisting of albumin, PEG, PVP, PEG block copolymer, PVP block copolymer, and a surfactant having a PEG chain attached to it.

[0015] <Flowing Device> The flowing device 100 of this embodiment will be described using Figures 1A and 1B. Figure 1A is a top view of the flowing device 100 of this embodiment. Figure 1B shows a cross-section of the dashed line section B-B' shown in Figure 1A.

[0016] The flow channel device 100 of this embodiment is a flow channel device 100 using a porous substrate 11 and has a flow channel region 16 surrounded by a flow channel wall 12. The flow channel region 16 includes an addition section 14 for adding liquid, a ligand section 21 where a ligand is provided, an absorption section 15 into which the liquid flows, and a connecting section 23 that connects any two selected from the group consisting of the addition section 14, the ligand section 21, and the absorption section 15. In the figure, the thick line indicates the inner wall 17 of the flow channel wall 12, and at least a part of the inner wall 17 is attached to one selected from the group consisting of albumin, PEG, PVP, PEG block copolymer, PVP block copolymer, and a surfactant having a PEG chain. In the figure, the dotted arrow indicates the direction of liquid flow. The liquid flows from upstream to downstream. For convenience of explanation, the side expected to be the surface during use is shown as the top and the side expected to be the back is shown as the bottom, with the top and bottom indicated by arrows. The flow path device 100 of this embodiment can be used as a standalone device, or it can be installed on a support or inside a housing case. The support 921 can be made of film, seal, plastic, or other molded product.

[0017] The flow channel device 100 of this embodiment is used for the analysis of a test substance. Analysis refers to the analysis of the test substance and includes the detection of the presence or absence of the test substance and the quantitative determination of the test substance. When a typical immunochromatographic method is adopted as the method for analysis, preferably the ligand section 21 and the connecting section 23 satisfy the following. That is, the ligand section 21 preferably includes a detection ligand section 211 on which a detection ligand 3211 is placed, and a capture ligand section 212 on which a capture ligand 3212 is fixed inside the porous substrate 11. The connecting section 23 preferably includes a first connecting section 231 connecting the addition section 14 and the detection ligand section 211, a second connecting section 232 connecting the detection ligand section 211 and the capture ligand section 212, and a third connecting section 233 connecting the capture ligand section 212 and the absorption section 15.

[0018] According to the flow channel device 100 of this embodiment, the liquid added to the detection ligand section 211 or the addition section 14 reaches the capture ligand section 212 via the detection ligand section 211, utilizing the driving force of capillary action. In the detection ligand section 211, the test substance contained in the sample reacts with the detection ligand 3211 to form a test substance-detection ligand complex. Furthermore, this complex reacts with the capture ligand 3212 in the capture ligand section 212, forming a capture ligand-test substance-detection ligand complex in the capture ligand section 212. Then, the signal information emitted from the capture ligand section 212 makes it possible to analyze the test substance in the sample. Analysis refers to the detection, identification, qualitative analysis, quantitative analysis, and other methods of obtaining information about the target substance.

[0019] The flow path device 100 of this embodiment can be used alone or in combination with other devices. Examples of devices to be combined with it include automated clinical blood analyzers, automated immunoassay analyzers, simple medical testing equipment, and rapid diagnostic testing equipment.

[0020] <Porous Substrate> Examples of porous substrates 11 include paper and membranes such as filter paper, plain paper, fine paper, watercolor paper, Kent paper, synthetic paper, and filtration membranes, which have an appropriate porosity and exhibit liquid permeability. However, it is not limited to paper and membranes, and can also be synthetic resin porous film, fabric, textile products, etc. Examples of materials include glass fiber, cellulose, cellulose acetate, polyethersulfone, and polyvinylidene fluoride. The method for forming the channel wall 12 will be described later, but when heating to form the channel wall 12, it is preferable that the heat resistance temperature of the porous substrate 11 is 140°C or higher.

[0021] <Flow channel walls> One method for forming the flow channel walls 12 is to print using an electrophotographic method with a hydrophobic resin as toner, and then heat to melt and permeate the resin. Thermoplastic resins are used as the resin. By doing so, the voids inside the porous substrate 11 are filled with resin, thereby forming the flow channel walls 12 inside the porous substrate 11.

[0022] The thermoplastic resin is not particularly limited, and for example, the following known resins can be used: polyester resin, vinyl resin, acrylic resin, styrene-acrylic resin, polyethylene, polypropylene, polyolefin, ethylene-vinyl acetate copolymer resin, ethylene-acrylic acid copolymer resin, etc. Among the above resins, polyester resin or styrene-acrylic resin is preferred, and styrene-acrylic resin is more preferred. Because a robust channel wall 12 can be formed inside the porous substrate 11, even if any of the group consisting of albumin, PEG, PVP, PEG block copolymer, PVP block copolymer, and surfactant having a PEG chain is attached to the inner wall 17, the elution and damage of the channel wall 12 are suppressed, and the sample can be flowed into the channel region 16 without leakage to the outside of the channel wall 12.

[0023] As the polyester resin, known polyester resins can be used. Specific examples of methods for producing polyester resin include the following: a method of dehydration condensation using a dibasic acid or its derivative and a dihydric alcohol as essential, and optionally including a trihydric or higher polybasic acid and its derivatives (carboxylic acid halides, esters, acid anhydrides), a monobasic acid, a trihydric or higher alcohol, or a monohydric alcohol.

[0024] Examples of dibasic acids include: aliphatic dibasic acids such as maleic acid, fumaric acid, itaconic acid, oxalic acid, malonic acid, succinic acid, dodecylsuccinic acid, dodecenylsuccinic acid, adipic acid, azelaic acid, sebacic acid, and decane-1,10-dicarboxylic acid; aromatic dibasic acids such as phthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, tetrabromophthalic acid, tetrachlorophthalic acid, hetic acid, hymic acid, isophthalic acid, terephthalic acid, and 2,6-naphthalenedicarboxylic acid; and so on.

[0025] Furthermore, examples of dibasic acid derivatives include carboxylic acid halides, esters, and acid anhydrides of the above-mentioned aliphatic dibasic acids and aromatic dibasic acids.

[0026] On the other hand, examples of dihydric alcohols include the following: acyclic aliphatic diols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, and neopentyl glycol; bisphenols such as bisphenol A and bisphenol F; alkylene oxide adducts of bisphenol A such as ethylene oxide adducts of bisphenol A and propylene oxide adducts of bisphenol A; aralkylene glycols such as xylylene diglycol; and so on.

[0027] Examples of polybasic acids with a valency of 3 or higher, and their anhydrides, include trimellitic acid, trimellitic anhydride, pyromellitic acid, and pyromellitic anhydride.

[0028] Examples of polymerizable monomers that can form styrene-acrylic resins include: styrene monomers such as styrene, α-methylstyrene, and divinylbenzene; unsaturated carboxylic acid esters such as methyl acrylate, butyl acrylate, methyl methacrylate, 2-hydroxyethyl methacrylate, t-butyl methacrylate, and 2-ethylhexyl methacrylate; unsaturated carboxylic acids such as acrylic acid and methacrylic acid; unsaturated dicarboxylic acids such as maleic acid; unsaturated dicarboxylic acid anhydrides such as maleic anhydride; nitrile vinyl monomers such as acrylonitrile; halogen-containing vinyl monomers such as vinyl chloride; nitro vinyl monomers such as nitrostyrene; and others. These can be used individually or in combination.

[0029] Styrene-acrylic resins may, if necessary, have crosslinking agents added when forming copolymers of styrene-based polymerizable monomers with acrylic acid esters or methacrylic acid esters. Examples include the following:

[0030] Divinylbenzene, bis(4-acryloxypolyethoxyphenyl)propane, ethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4-butanediol diacrylate, 1,5-pentanediol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol #200 diacrylate (CH ２ =CHCOO(CH ２ CH ２ O) ｎ OCCH=CH ２ , n = 4, molecular weight 308), polyethylene glycol #400 diacrylate (CH ２ =CHCOO(CH ２ CH ２ O) ｎ OCCH=CH ２ , n = 9, molecular weight 508), each diacrylate of polyethylene glycol #600 (CH ２ =CHCOO(CH ２ CH ２ O) ｎ OCCH=CH ２ , n = 14, molecular weight 708), dipropylene glycol diacrylate, polypropylene glycol diacrylate, polyester type diacrylate (MAND A, Nippon Kayaku Co., Ltd.), and those obtained by changing the above acrylates to methacrylates.

[0031] Examples of the polyfunctional crosslinkable monomers include the following. Pentaerythritol triacrylate, trimethylolethane triacrylate, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, oligoester acrylate and its methacrylate, 2,2-bis(4-methacryloxy-polyethoxyphenyl)propane, diacryl phthalate, triallyl cyanurate, triallyl isocyanurate, triallyl trimellitate, diaryl chlorendate.

[0032] The preferred range for the weight-average molecular weight (Mw) of the binder resin is 3,000 to 500,000, more preferably 5,000 to 300,000, and even more preferably 7,500 to 100,000.

[0033] A material containing a thermoplastic resin and wax (oil) may be used to form the channel wall. The material used as the wax is not particularly limited, and known waxes used in toners such as the following can be used: Esters of monohydric alcohols and aliphatic carboxylic acids, or esters of monohydric carboxylic acids and aliphatic alcohols, such as behenyl behenate, stearyl stearate, and palmityl palmitate; esters of dihydric alcohols and aliphatic carboxylic acids, such as ethylene glycol dibehenate and hexanediol dibehenate; esters of dihydric carboxylic acids and aliphatic alcohols, such as dibehenyl sebacate; esters of trihydric alcohols and aliphatic carboxylic acids, or esters of trihydric carboxylic acids and aliphatic alcohols, such as glycerol tripehenate; esters of tetrahydric alcohols and aliphatic carboxylic acids, or esters of tetrahydric carboxylic acids and aliphatic alcohols, such as pentaerythritol tetrastearate and pentaerythritol tetrapalmitate; dipentaerythritol Esters of hexavalent alcohols and aliphatic carboxylic acids, such as xastearate and dipentaerythritol hexapalmitate, or esters of hexavalent carboxylic acids and aliphatic alcohols; esters of polyhydric alcohols and aliphatic carboxylic acids, such as polyglycerin behenate, or esters of polyhydric carboxylic acids and aliphatic alcohols; natural ester waxes, such as carnauba wax and rice wax; hydrocarbon waxes (petroleum-based waxes such as paraffin wax, microcrystalline wax, and petrolatum and their derivatives; waxes produced by the Fischer-Tropsch process and their derivatives; polyolefin waxes such as polyethylene wax and polypropylene wax and their derivatives); higher aliphatic alcohols; fatty acids such as stearic acid and palmitic acid; acid amide waxes. These waxes may be used individually or in combination.

[0034] Furthermore, the method for forming the channel wall 12 is not limited to heating, melting, and impregnating the resin; other methods such as impregnating with wax using a wax printer, screen printing, inkjet printing, photolithography, thermal transfer, or stamping are also acceptable.

[0035] The inner wall 17 of the channel wall 12 refers to the channel wall 12 located inside the porous substrate 11 at the interface between the channel region 16 and the region where the channel wall 12 is formed. The channel wall 12 is installed inside the porous substrate 11 and has a contact angle of 111° or less with respect to water droplets on its surface. In this embodiment, the inner wall 17 of the channel wall 12 is coated with one of the following: albumin, polyethylene glycol (PEG), polyvinylpyrrolidone (PVP), PEG block copolymer, PVP block copolymer, or a surfactant having a PEG chain. Examples of albumin include albumin derived from the serum of vertebrates such as cattle, ovalbumin, and milk albumin. By binding to the inner wall 17 through hydrophobic interactions, the albumin adheres to the inner wall 17 so that its hydrophilic structure faces the channel region 16, and the channel wall becomes hydrophilic. As a result, the interface between the channel region 16 and the channel wall 12 becomes more compatible with water, and the flow velocity of the liquid flowing through the channel region 16 is improved. PEG and PVP of various molecular weights can be used as long as they can adhere to the channel wall 12 and hydrophilize the inner wall 17. To increase the adhesion to the channel wall 12, block copolymers containing PEG chains or PVP chains can be used. Copolymers with polyethylene, polylactide, etc., can be used. Examples of surfactants having PEG chains include Tween 20, Tween 80, Triron X-100, Brij-35, NP-40, acetylenol, tocopherolane, etc. In surfactants having PEG chains, the hydrophobic structure is bonded to the inner wall 17 by hydrophobic interactions, so that the PEG chains adhere to the inner wall 17 so that they face the channel region 16, and the channel wall becomes hydrophilic. As a result, the interface between the channel region 16 and the channel wall 12 becomes more compatible with water, and the flow velocity of the liquid flowing through the channel region 16 is improved.

[0036] As the flow velocity of the liquid flowing through the flow path region 16 increases, substances such as the analyte, detection ligand, washing solution, signal generation material or signal amplification material can reach the ligand part more quickly. Thereby, within a certain time after the addition of the sample, the formation of the capture ligand-analyte-detection ligand complex can be rapidly carried out. Also, since the signal generation reaction and the signal amplification reaction can be started earlier, a higher signal generation amount and signal amplification amount can be obtained during a certain time until the measurement of the test substance. That is, by increasing the flow velocity of the liquid flowing through the flow path region 16, a sufficient signal amount for determining or quantifying the presence of the analyte can be obtained in a short time, so that the rapid measurement of the analyte can be carried out.

[0037] The method of adhering these substances is not particularly limited, and examples include immersing the flow path device in a solution of these substances for a certain time or filling the flow path region 16 with this solution and wetting it for a certain time. The presence or absence of the adhesion of the substance can be confirmed by general analysis methods such as protein staining with Coomassie Brilliant Blue, staining by immunological methods, and mass spectrometry including pyrolysis GC / MS.

[0038] <Flow Path Region> The flow path region 16 is surrounded or sandwiched by the flow path wall 12 and is a portion where the pores of the porous substrate 11 are not filled by the flow path wall 12. Thereby, the pores can form the flow path 18 in the porous substrate 11, and the liquid can flow along the flow path 18 by capillary action without leaking out of the outside of the flow path wall 12.

[0039] The flow path 18 refers to the path of the liquid flow generated in the flow path region 16 or a part thereof. By adding a liquid to the addition part 14, a flow occurs from the addition part 14 toward the absorption part 15 through the connection part 23 and the ligand part 21. By appropriately determining the flow path region 16, the target flow path 18 can be formed.

[0040] The shape of the flow path region 16 in this embodiment is not particularly limited, and for example, a straight shape, dumbbell shape, L-shape, T-shape, U-shape, U-shape, Y-shape, or cross shape can be used. Branching points and merging points may also be provided to connect these shapes.

[0041] The width of the flow path region 16 may be uniform, or it may be made wider or narrower at any point. The flow path region 16 may be provided with a flow path shape or material that suppresses or prevents backflow. The flow path shape or material provided in the flow path region 16 that suppresses or prevents backflow can also be called a backflow suppression structure. The entire or a part of the flow path region 16 may be surrounded by a flow path wall 12 so as to have a shape that suppresses backflow, such as a venous valve structure or a Tesla valve structure. In addition, materials may be arranged to reduce fluid permeability by filling voids inside the flow path at any point in the flow path region 16. The material is not particularly limited, but water-soluble materials such as inorganic salts, organic salts, sugars, water-soluble polymers or compositions containing them, and non-water-soluble materials such as resins can be used. The backflow suppression structure has a hydrophobic resin attached to it and can be said to have fluid permeability. More specifically, the backflow suppression mechanism contains a hydrophobic resin and allows liquids such as specimens to pass through, but it is a region where fluid permeability is reduced compared to the region of the flow path region 16 outside the backflow suppression structure. From the perspective of reducing the permeability of any part of the flow path, the backflow suppression structure can also be called a flow velocity control unit. For example, when a washing solution or a liquid containing signal generating material or signal amplifying agent is added upstream of the location where the flow path shape and material are installed, and a sample is added downstream of that location, it is possible to suppress the backflow of some of the sample upstream and prevent it from mixing with the liquid added upstream, allowing it to flow downstream in an orderly manner. As a result, after the sample is flowed first to generate the antigen-antibody reaction, the washing solution, the liquid containing signal generating material or signal amplifying agent flows in, allowing the washing process, signal generation reaction, and signal amplification reaction to occur in an orderly manner. In other words, multi-stage reactions and multi-stage processes can be carried out efficiently.

[0042] As described later in the second to sixth embodiments, the flow path may be branched. Multiple flow paths 18 branched from the same flow path 18 may be called parallel flow paths or branching sections 402. The branching section 402 is provided so that the liquid distributed at the branching point 401 can flow through it. By providing branching points and branching sections in the flow path 18, liquid distribution and merging can be performed. Samples, washing solutions, liquids containing signal generating materials and signal amplifying agents can be distributed to multiple flow paths branched from a single addition section, or they can be dropped into multiple addition sections and merged or flowed sequentially. By providing branching sections, a single liquid can be arbitrarily divided into a liquid used for reaction with a ligand, a liquid used for reaction with another ligand, a liquid for washing the ligand section after the reaction, a liquid containing signal generating materials and signal amplifying agents, etc. Flow path washing materials, signal generating materials, signal amplifying agents, reaction auxiliary materials, pH adjusting materials, reaction stopping materials, etc., may be placed in the branching section. For example, by placing signal generating materials or signal amplifying agents inside some of the parallel channels among multiple parallel channels, the sample liquid can be distributed, and a liquid without signal generating materials or signal amplifying agents and a liquid containing signal generating materials or signal amplifying agents can be prepared inside the channels. To ensure that the flow velocity of the sample is relatively faster than the flow velocity of the parallel channels containing the signal generating materials or signal amplifying agents, albumin, PEG, PVP, PEG block copolymer, PVP block copolymer, and surfactants having PEG chains can be attached to the inner walls 17 of the channel walls 12 of the sample channels, and gelatin, PVA, PVA block copolymer, etc. can be attached to the inner walls 17' of the channel walls 12 in the parallel channel section, thereby delaying the flow of the sample containing signal generating materials or signal amplifying agents.

[0043] The inner walls 17 and 17' may both be coated with albumin, PEG, PVP, PEG block copolymer, PVP block copolymer, and surfactants having PEG chains. By arranging materials to fill the voids inside the channel surrounded by the inner wall 17', thereby reducing the permeability, samples containing signal generating materials and signal amplifying agents can be flowed with a delay. By using non-water-soluble materials such as resins, samples flowing into the channel surrounded by the inner wall 17' will have their flow obstructed, reducing their flow velocity and causing them to flow with a delay. Furthermore, by using water-soluble materials such as inorganic salts, organic salts, sugars, signal generating materials and signal amplifying agents, and water-soluble polymers, or compositions containing these, samples flowing into the channel surrounded by the inner wall 17' will similarly flow with a delay, but the flow velocity will gradually increase as the filling material dissolves, allowing the delayed samples to flow quickly. When using these materials, they may be placed in the same position as the signal generating materials and signal amplifying agents, or they may be placed upstream, downstream, or both upstream and downstream of the location where the signal generating materials and signal amplifying agents are placed.

[0044] Furthermore, a liquid-holding member such as absorbent cotton may be placed above the flow path enclosed by the inner wall 17'. The liquid-holding member may contain a signal-generating material or a signal-amplifying agent beforehand, or if it does not, it may be placed upstream, downstream, or both upstream and downstream of the location where the signal-generating material or signal-amplifying agent is placed. This allows a sample without the signal-generating material or signal-amplifying agent to flow first to generate an antigen-antibody reaction, after which a sample containing the signal-generating material or signal-amplifying agent flows in to generate a signal-generating reaction or a signal-amplifying reaction. Even if the signal-generating material or signal-amplifying agent is not placed, the sample liquid can be distributed to divide the sample into one that flows first toward the ligand section and another that merges later. After the sample that flows first generates an antigen-antibody reaction, the sample that merges later flows into the ligand section and can wash the ligand section. In other words, multi-stage reactions and multi-stage processes can be carried out simply by adding a sample.

[0045] The flow channel region 16 may be formed on a single porous substrate 11, or it may be formed by overlapping or connecting multiple porous substrates 11. For example, the flow channel regions 16 can be formed by overlapping porous substrates 11 so that the flow channel regions of each porous substrate 16 are in contact with each other. This allows for the transfer of liquid between multiple porous substrates and enables the formation of more complex flow channel regions 16.

[0046] For example, a porous substrate 11 containing an additive section 14, a channel 18, a ligand section 21, and an absorption section 15 can be superimposed to form a channel region 16. Alternatively, a porous substrate 11'' may be sandwiched between the channels 18 and 18', having a connecting section 801 that can separate the channels 18 and 18' and connect the additive section 14 and 14', and a connecting section 802 that can connect the channels 18 and 18'. This allows for the distribution and merging of liquids in the direction perpendicular to the substrate surface. The porous substrates 11' and 11'' may have the same or different liquid permeability as the porous substrate 11. Using a porous substrate 11' with low liquid permeability can lower the flow velocity of the liquid passing through the channel 18'. The flow velocity of the liquid passing through the channel 18' can also be lowered by attaching gelatin, PVA, PVA block copolymer, etc., to the inner wall 17' of the channel 18'. By allowing the liquid that has passed through channel 18 to flow first and generate an antigen-antibody reaction, the liquid that has passed through channel 18' flows into channel 18, thereby cleaning channel 18 downstream of the connection point. Furthermore, if signal generating material or signal amplifying agent is placed inside channel 18', liquid containing the signal generating material or signal amplifying agent will flow from channel 18' to channel 18. By providing a connection point upstream of the ligand section, cleaning, signal generating reactions, and signal amplification reactions can be generated in a sequential manner. In other words, multi-stage reactions and multi-stage processes can be easily implemented. It is also possible to form a channel region 16 by connecting a single porous substrate 11 containing an additive section 14, channel 18, ligand section 21, and absorption section 15, and a single porous substrate 11' containing an additive section 14' and channel 18'. By connecting only the additive section 14 and the additive section 14', the liquid added to the additive section can be distributed to channel 18 and channel 18'. After distribution, the porous substrate 11' is moved to separate the additive section 14 and the additive section 14', and the flow path 18 and the flow path 18' are connected, allowing the liquid that has passed through the flow path 18' to flow into the flow path 18. In other words, after the liquid that has flowed in from the flow path 18 is allowed to flow to generate an antigen-antibody reaction, the flow path 18 can be cleaned by letting the liquid that has flowed in from the flow path 18' flow through it.Furthermore, by placing signal generating material and signal amplifying agent inside the channel 18', a liquid containing the signal generating material and signal amplifying agent will flow from channel 18' to channel 18. By moving the porous substrate 11', cleaning processes, signal generating reactions, and signal amplification reactions can be carried out in a sequential manner. In other words, multi-stage reactions and multi-stage processes can be easily implemented.

[0047] Similarly, a porous substrate 11 containing a ligand portion 21 and an absorption portion 15, and a porous substrate 11' containing an additive portion 14 and a branching portion 402 can be connected to form a flow channel region 16. By connecting the flow channel 18 and the branching portion 402 so that they are in communication, the liquid added to the additive portion 14 is distributed at the branching point, and after the liquid that has passed through the branching portion 402, which is in communication with the flow channel 18, flows into the flow channel 18, the porous substrate 11' can be moved so that the branching portion 402', which was not previously in communication, is newly connected to the flow channel 18. After the liquid that has flowed in from the branching portion 402 is allowed to flow and an antigen-antibody reaction is generated, the flow channel 18 can be cleaned by letting the liquid that has flowed in from the branching portion 402' flow. Furthermore, if a signal generating material or a signal amplifying agent is placed inside the branching portion 402', a liquid containing the signal generating material or signal amplifying agent will flow from the branching portion 402' into the flow channel 18. By moving the porous substrate 11', cleaning processes, signal generating reactions, and signal amplification reactions can be generated in a sequential manner. In other words, multi-step reactions and multi-step processes can be easily implemented.

[0048] <Addition section> The addition section 14 is located within the flow path region 16 and is for adding liquid to the flow path 18.

[0049] The detection ligand section 211 communicates with the capture ligand section 212 downstream. The addition section 14 may include a connecting section 23, a ligand section 21, and an absorption section 15 that communicate downstream; that is, the connecting section 23, the ligand section 21, and the absorption section 15 may constitute the addition section 14. The addition section 14 may communicate with multiple ligand sections 21. By arranging and immobilizing a detection ligand 3211 and a capture ligand 3212 for a specific test substance in each of the multiple detection ligand sections 211 and multiple capture ligand sections 212 that communicate with each other, multiple test substances can be detected simultaneously by simply dropping one type of sample into the addition section 14.

[0050] The liquid added to the addition section 14 can be a sample, a sample containing a detection ligand, a flow channel cleaning solution, a liquid containing a signal amplification reagent, an auxiliary solution for the signal amplification reaction, a liquid containing signal generating materials such as a chromogenic agent, a liquid containing a secondary antibody against the detection ligand 3211, a reaction stop solution for the signal amplification reaction, a sample containing an additive that promotes the release of the detection ligand, or a mixture thereof, or any liquid containing these. These liquids may be used individually or in combination. These liquids may be added to the addition section 14 sequentially. In the case of a flow channel device having multiple addition sections, each of these liquids may be added to each of the multiple addition sections. The liquid can be added to the flow channel device by methods such as dropping or spraying, or the addition section 14 of the flow channel device may be brought into contact with the liquid. Alternatively, a liquid-holding member containing the liquid may be brought into contact, or the liquid may be added via a liquid-holding member provided on the flow channel. By bringing the liquid into contact via a liquid-holding member, the liquid can be directed only into the flow channel by the capillary action of the porous substrate, suppressing unintended liquid spread such as liquid running along the surface of the flow channel. Furthermore, it is possible to add more liquid to the flow channel device than the amount of liquid that can be contained within the flow channel.

[0051] The flow channel device may be deformed to bring it into contact with a liquid-containing liquid-holding member. For example, if a material or member that expands or contracts when it absorbs liquid is provided in the flow channel, the flow of the sample can cause deformation of the flow channel device. That is, by arranging the flow channel device and liquid-holding member so that the flow channel comes into contact with the liquid-holding member after deformation, the flow channel device deforms after the sample has flowed through the flow channel, causing the flow channel to come into contact with the liquid-holding member, and allowing the liquid to flow from the liquid-holding member into the flow channel. Instead of a flow channel device, deformation of a permeable member equipped with a material or member that expands or contracts with respect to liquid can also be used. If that member is brought into contact with the flow channel, the flow of the sample can cause deformation of the member. That is, by arranging the flow channel device and liquid-holding member so that the member comes into contact with the liquid-holding member after deformation, the liquid can flow from the liquid-holding member through the member into the flow channel after the sample has flowed through the flow channel.

[0052] Furthermore, the additive section 14 may contain materials such as a detection ligand, a channel cleaning material, a signal generating material, a signal amplifier, a reaction auxiliary material, a pH adjusting material, a reaction stopping material, and an additive that promotes the release of the detection ligand. By adding a solvent or sample to the additive section 14, a complex of the test substance and detection ligand, a channel cleaning solution, a liquid containing a signal generating material and a signal amplifier, a reaction auxiliary solution, a pH adjusting solution, a reaction stopping solution, a detection ligand release solution, etc., can be generated inside the additive section 14 and released into the channel.

[0053] The flow channel device 100 may be provided with a storage section 1101 that is not in communication with the flow channel 18 but is surrounded by a flow channel wall 12 and has open pores in the porous substrate 11. The storage section 1101 can contain a flow channel cleaning solution, a liquid containing a signal amplification reagent, an auxiliary solution for the signal amplification reaction, a liquid containing signal generating materials such as a chromogenic agent, a liquid containing a secondary antibody against the detection ligand 3211, a reaction stop solution for the signal amplification reaction, or a mixture thereof. Alternatively, by adding any solvent to the storage section 1101, materials such as flow channel cleaning materials, signal generating materials, signal amplification agents, reaction auxiliary materials, secondary antibodies against the detection ligand 3211, pH adjusting materials, and reaction stop materials can be pre-included to prepare these solutions. By bringing a permeable member such as a porous substrate into contact with the storage section 1101 so that it connects to the flow channel 18, liquid can be flowed from the storage section 1101 to the flow channel 18.

[0054] By flowing the fluid channel cleaning solution, the liquid containing the signal amplification reagent, the auxiliary solution for the signal amplification reaction, the liquid containing signal generating materials such as a chromogenic agent, and the liquid containing the secondary antibody against the detection ligand 3211 downstream from the addition section 14, any residual detection ligand 3211 or test substance that has not reached the capture ligand section 212 or absorption section 15 after the sample has been added can be washed away, thereby suppressing background signals.

[0055] The flow path cleaning solution can be a buffer solution or a buffer solution containing a surfactant. Examples of signal amplification reagents include fluorescent dye-modified tyramide, hapten-labeled tyramide, biotin-labeled tyramide, silver ions, silver ion reducing agents, 2-fluoromethylphenyl phosphate-fluorescent dye conjugate, 2-(fluoromethyl)phenyl phosphate-fluorescent dye conjugate, 2-(fluoromethyl)phenyl phosphate-biotin conjugate, 2-(fluoromethyl)phenyl phosphate-hapten conjugate, 2-(difluoromethyl)phenyl phosphate-fluorescent dye conjugate, 2-(difluoromethyl)phenyl phosphate-biotin conjugate, and 2-(difluoromethyl)phenyl phosphate-hapten conjugate.

[0056] Examples of signal-generating materials include dyes, pigments, colored particles, magnetic particles, gold nanoparticles, gold colloids, silver nanoparticles, silver colloids, fluorescent particles, luminescent particles, fluorescent dyes, chemiluminescent substrates, enzymes, and materials that generate signals through enzymatic reactions. These materials may be modified with antibodies against biotin, avidin, streptavidin, or haptens. By labeling the detection ligand 3211 with molecules that specifically bind to these materials, the signal-generating materials can be labeled to the detection ligand 3211 via a binding reaction. Alternatively, a liquid containing the signal-amplifying reagent can be flowed through the system, followed by a liquid containing the signal-generating materials. These signal-generating materials may be used individually or in combination.

[0057] Furthermore, as materials that exhibit signal generation by enzymatic reactions, the following are used: 2,2'-azinobis[3-ethylbenzothiazoline-6-sulfonic acid]-diammonium salt, o-phenylenediamine dihydrochloride, 3,3',5,5'-tetramethylbenzidine, 3,3'-diaminobenzidine tetrahydrochloride, Amplex® Red, 3-p-hydroxyphenylpropionic acid, fluorescent dye tyramide, luminol, lucigenin derivative / reducing compound, p-nitrophosphate, 5-bromo-4-chloro-3-indolyl phosphate / nitrobluetetrazolium (BCIP / NBT), 4-methylumbelliferyl phosphate, and fluorescent dye. Examples of surfactants include diphosphonate, 7-hydroxy-9H-(1,3-dichloro-9,9-dimethylacridin-2-one), AMPPD®, CSPD®, CDP-Star®, etc. These can be selected according to the type of enzyme to be labeled with detection ligand 3211. Examples of surfactants include Tween® 20, Tween 80, Triron® X-100, SDS, CHAPS, Brij-35, NP-40, Octyl Glucoside, acetylenol, etc. These solutions may contain surfactants, metal ions, coenzymes, etc., to promote signal generation and signal amplification reactions. From the viewpoint of promoting enzymatic reactions, the concentration of the surfactant is preferably 5% or less.

[0058] The flow channel device 100 may further include a liquid-holding member. The liquid-holding member can hold liquid and release it into the flow channel when it comes into contact with the addition part. The liquid-holding member may have functions such as blood cell separation, plasma separation, filtration, material support, and adsorption of specific materials. Although not particularly limited, materials such as detection ligands, flow channel cleaning materials, signal generating materials, signal amplifiers, reaction auxiliary materials, pH adjusting materials, and reaction stopping materials may be pre-filled inside the liquid-holding member. By simply adding a solvent to the liquid-holding member, detection ligand solution, flow channel cleaning solution, liquid containing signal generating material or signal amplifier, reaction auxiliary solution, pH adjusting solution, reaction stopping solution, etc., can be generated inside the liquid-holding member and released into the flow channel. Examples of liquid-holding members include paper and membranes such as filter paper, plain paper, fine paper, watercolor paper, Kent paper, synthetic paper, and filtration membranes that have an appropriate porosity and can hold liquid, but are not limited to paper and membranes, and may also be synthetic resin porous films, cloth, absorbent cotton, cotton, gauze, textile products, etc. Examples of materials include glass fiber, cellulose, cellulose acetate, polyethersulfone, and polyvinylidene fluoride.

[0059] <Ligand section> The ligand section 21 refers to the portion within the flow channel region 16 where the ligand is provided. "Provided with a ligand" means that the ligand is present at the time of measurement. This could mean the ligand is positioned, fixed, or, for example, a ligand held on another substrate that moves during measurement. "Fixed" means that the ligand is fixed within the flow channel region 16 to the extent that it does not move due to the liquid flow. "Placed" means that the ligand is movable within the flow channel region 16 due to the liquid flow. However, when the ligand is said to be placed, a portion of the ligand may be fixed, or even if the ligand is fixed, a portion of the ligand may be movable. The ligand only needs to be able to specifically bind to the test substance. An example of specific binding is the antigen-antibody reaction. When the test substance is an antigen, the ligand can be an antibody; when the test substance is an antibody, the ligand can be an antigen.

[0060] When employing a typical immunochromatographic method, the fluid device 100 includes a detection ligand unit 211 and a capture ligand unit 212 as the ligand unit 21. The detection ligand unit 211 and the capture ligand unit 212 will be described below.

[0061] <Detection Ligand Section> The detection ligand section 211 is provided within the flow channel region 16. The detection ligand 3211 may be arranged inside the porous substrate 11 as shown in Figure 2, or, as shown in Figure 3, the detection ligand 3211 may be provided above the substrate surface in the direction perpendicular to the substrate surface before measurement. The detection ligand section 211 communicates with the addition section 14 upstream and with the capture ligand section 212 downstream. The detection ligand 3211 arranged in the detection ligand section 211 may contain additives composed of surfactants, sugars, water-soluble polymer compounds, etc. When a sample is added, the detection ligand 3211 is efficiently released, improving the sensitivity and accuracy of the detection of the test substance. Examples of surfactants include Tween 20, Tween 80, Triron X-100, SDS, CHAPS, Brij-35, NP-40, Octyl Glucoside, acetylenol, etc. Surfactants can increase the solubility of the detection ligand 3211. The sugar can be a monosaccharide, oligosaccharide, or polysaccharide, such as sucrose, trehalose, lactose, mannose, glucose, arabinose, xylose, maltose, dextran, or amylose starch. Sugars can suppress the denaturation of the detection ligand 3211. Examples of water-soluble polymer compounds include polyethylene glycol (PEG), polyvinyl alcohol (PVA), polyglutamic acid, polyvinylpyrrolidone (PVP), polyaspartic acid, polylactic acid, polyethyleneimine, casein, alkali-treated casein, albumin, ovalbumin, and gelatin. Water-soluble polymers can suppress the nonspecific adsorption and aggregation of the detection ligand 3211. Surfactants, sugars, and water-soluble polymer compounds can be of various molecular weights as long as they are water-soluble compounds. It is preferable to use a mixture of sugar and surfactant, a mixture of sugar, surfactant and albumin, albumin, a mixture of albumin and surfactant, or a mixture of albumin and sugar as an additive. This allows for efficient release of the detection ligand 3211 placed in the detection ligand section 211. It is preferable to dry the detection ligand 3211 placed in the detection ligand section 211 at 0°C to 50°C or by freeze-drying.

[0062] The detection ligand 3211 and the capture ligand 3212 both specifically bind to the test substance, but preferably their binding sites are different. It is preferable that the detection ligand 3211 is modified with a labeling molecule. The ligand only needs to be able to specifically bind to the target substance, and the specific binding is preferably an antigen-antibody reaction. The ligand is preferably a monoclonal antibody, a polyclonal antibody, or an antibody fragment (Fab fragment, F(ab')). ２ Fragments, etc., and antigens (if the test substance is an antibody) can be used. As for the labeling molecule, it is preferable to use a molecule that emits a signal that provides information about the presence and concentration of the test substance, as will be described later.

[0063] When using detection ligand 3211 that is not modified with a labeling molecule, a secondary antibody against detection ligand 3211 can be used in combination, and it is preferable that the secondary antibody is modified with a labeling molecule. For example, by adding a sample to form a capture ligand-test substance-detection ligand complex, and then deploying a secondary antibody modified with a labeling molecule, the labeling molecule can be supported on the capture ligand-test substance-detection ligand complex via binding between detection ligand 3211 and the secondary antibody. Since secondary antibodies modified with various labeling molecules are commercially available, a highly versatile fluid device 100 can be constructed.

[0064] In detection in this embodiment, the sample may be directly added to the detection ligand section 211 where the detection ligand 3211 is placed. The test substance contained in the sample can be uniformly mixed with the detection ligand 3211, efficiently forming a test substance-detection ligand complex and increasing detection sensitivity. Alternatively, the sample may be added to the first connecting section 231. For example, if a liquid different from the sample is added to the addition section 14 immediately after adding the sample to the first connecting section 231, the sample and the liquid will flow continuously, allowing the sample to flow downstream efficiently while suppressing backflow. The sample can be added by methods such as dropping or spraying, or by contacting the desired location. Alternatively, a liquid-holding member containing the sample may be brought into contact, or the sample may be added to the detection ligand 3211 or a liquid-holding member provided on the upper part of the first connecting section 231. By contacting via a liquid-holding member, the sample can be directed only into the flow path due to the capillary action of the porous substrate, suppressing unintended spread of the sample, such as the sample spreading along the surface of the flow path. Furthermore, it is possible to add a sample to the flow channel device in a volume exceeding the amount of liquid that can be contained within the flow channel.

[0065] As mentioned above, as shown in Figure 2, the detection ligand 3211 can be placed inside the detection ligand section 211. In this way, the sample flows through a single porous substrate 11, preventing leakage of the sample and ensuring uniform flow. Alternatively, as shown in Figure 3, the detection ligand 3211 may be placed on top of the detection ligand section 211 in the direction of gravity. That is, another porous substrate 301 in which the detection ligand 3211 is placed may be placed on top of the detection ligand section 211. If a porous substrate with high elution properties of the detection ligand 3211 is used as the other porous substrate 301, the detection ligand 3211 can be mixed more uniformly. Furthermore, if a blood cell separation membrane is used as the other porous substrate 301, blood cell separation and the reaction between the test substance and the detection ligand 3211 can be performed simultaneously, and the test substance-detection ligand complex can be deployed in the flow channel device 100.

[0066] <Labeling Molecules> As labeling molecules, molecules that emit a signal to obtain information about the presence and concentration of the test substance, signal generating materials that can produce such signal-emitting molecules, or molecules for binding these molecules to the detection ligand 3211 can be used. For example, dyes, pigments, colored particles, magnetic particles, gold nanoparticles, gold colloids, silver nanoparticles, silver colloids, fluorescent particles, luminescent particles, fluorescent dyes, chemiluminescent substrates, ruthenium complexes, horseradish peroxidase, alkaline phosphatase, glucose oxidase, biotin, avidin, streptavidin, haptens, etc. can be used. From the viewpoint of highly sensitive detection, it is preferable to use enzymes. Enzymatic reactions can catalytically generate molecules that emit signals such as color development, fluorescence, and luminescence, and by allowing the reaction to proceed for a certain period of time, the signal can be amplified. In the flow channel device 100 of this embodiment, because the flow rate is high, the signal-emitting reaction can be started quickly, and the flow rate of the signal-generating material and signal amplifier can be increased, and as a result, the detection sensitivity can be increased. When horseradish peroxidase is used as the labeling molecule, for example, 2,2'-azinobis[3-ethylbenzothiazoline-6-sulfonic acid]-diammonium salt, o-phenylenediamine dihydrochloride, 3,3',5,5'-tetramethylbenzidine, 3,3'-diaminobenzidine tetrahydrochloride, AmplexRed, 3-p-hydroxyphenylpropionic acid, fluorescent dyes such as tyramide, luminol, and lucigenin derivatives / reducing compounds can be used as signal generating materials, and these signal generating materials are used in combination with hydrogen peroxide. When alkaline phosphatase is used as the labeling molecule, for example, p-nitrphentlphosphatate, 5-bromo-4-chloro-3-indolyl phosphate / nitrobluetetrazolium (BCIP / NBT), 4-methylumbelliferyl phosphate, fluorescein diphosphatate, 7-hydroxy-9H-(1,3-dichloro-9,9-dimethylacridin-2-one), AMPPD, CSPD, CDP-Star, etc. can be used as signal generating materials.

[0067] <Capture Ligand Section> The capture ligand section 212 is provided within the flow channel region 16, and the capture ligand 3212 is fixed inside the substrate. The capture ligand section 212 communicates with the detection ligand section 211 upstream and with the absorption section 15 downstream.

[0068] The detection ligand 3211 and the capture ligand 3212 both specifically bind to the test substance, but preferably their binding sites are different. The ligand only needs to be able to specifically bind to the target substance, and specific binding is preferably an antigen-antibody reaction. The ligand is preferably a monoclonal antibody, a polyclonal antibody, or an antibody fragment (Fab fragment, F(ab')). ２ Fragments, antigens (if the test substance is an antibody) can be used. The capture ligand 3212 can be immobilized by adding it to the porous substrate 11 and drying it. The capture ligand 3212 added to the capture ligand section 212 is preferably dried at 0°C to 50°C or by freeze-drying. Before adding the capture ligand 3212, a nitrocellulose solution, PVDF solution, etc., may be added to the capture ligand section 212 and dried. By incorporating protein-adsorbing nitrocellulose, PVDF, etc., into the porous substrate 11 of the capture ligand section 212, the immobilization of the capture ligand 3212 can be promoted. If nitrocellulose, PVDF, etc., are not used, the amount and concentration of the capture ligand 3212 can be increased. Increasing the amount can promote adsorption by aggregation inside the porous substrate 11.

[0069] <Absorption Section> The absorption section 15 is provided within the flow path region 16 and is for absorbing and retaining the liquid that has passed through the detection ligand section 211 and the capture ligand section 212. The absorption section 15 communicates with the capture ligand section 212 upstream of it. Preferably, the absorption section 15 has a water absorption capacity that can absorb all the liquid used for detection in the flow path device 100. If the absorption section 15 has a small water absorption capacity, another absorbent material may be stacked on top of the absorption section 15. This allows for miniaturization of the device, making handling and transportation easier.

[0070] <Connecting Section> The connecting section 23 is provided within the flow path region 16 and is for connecting the additive section 14, the ligand section 21, and the absorption section 15, respectively. The width of the connecting section 23 is not particularly limited, but it is preferably 4 mm or less. By narrowing the flow path width, the cross-sectional area of ​​the flow path becomes smaller, and the flow velocity can be increased.

[0071] <Test Substances> The test substances used in this disclosure are substances corresponding to the target of the immunoassay. There are no particular limitations, but examples include HBs antigen, influenza antigen, rotavirus antigen, adenovirus antigen, norovirus antigen, mumps virus antigen, cytomegalovirus antigen, herpes simplex virus antigen, herpes zoster virus antigen, SARS antigen, coronavirus antigen, HBs antibody, HCV antibody, HTLV-1 antibody, HIV antibody, EBV antibody, RSV antibody, rubella virus antibody, measles virus antibody, SARS antibody, coronavirus antibody, enterovirus antibody, dengue virus antibody, pneumococcal antigen, group A and B hemolytic streptococcal antigen, gonorrhea antigen, Legionella antigen, Mycobacterium tuberculosis antigen, Escherichia coli O157 antigen, Neisseria tetanus antigen, Mycoplasma antibody, Helicobacter pylori antibody, E. coli verotoxin, Clostridium difficile These include infectious disease antigens and antibodies such as physyl toxin, Chlamydia antigen, Treponema pallidum antibody, Hepatitis C virus antibody, Hepatitis B virus surface antigen, Human immunodeficiency virus antigen, Human immunodeficiency virus antibody, Malaria antibody, Toxoplasma antibody, and Candida mannan antigen; inflammation and infection markers such as C-reactive protein (CRP) and procalcitonin; low molecular weight antigens such as calcitonin, thyroxine, estrogen, and elastoradiol; tumor-associated antigens such as AFP, CEA, ferritin, CA19-9, CA125, and PIVKA; high molecular weight hormones such as TSH and insulin; cytokines such as IL-1, IL-2, and IL-6; growth factors such as EGF and PDGF; and cardiomyopathy and thrombosis markers such as FDP, D-dimer, CK-MB, BNP, NT-proBNP, myoglobin, troponin I, and troponin T.

[0072] The flow channel device 100 of this disclosure can be used for the diagnosis of infectious diseases, thrombosis, cardiomyopathy, cerebral infarction, etc., as it enables rapid analysis of the substance being tested.

[0073] The types of samples that may contain the test substance are not particularly limited and include biological samples such as urine, blood, sweat, tears, saliva, and mucus, environmental samples, food and beverage samples, and liquid samples derived from these, or diluted or concentrated solutions with increased or decreased amounts of water. The test substance can be used not only for medical diagnosis, but also for testing and analysis in fields such as healthcare, life sciences, agriculture and livestock farming, food, environmental conditions such as soil and water quality, and drug testing.

[0074] <Second Embodiment> The second embodiment provides a flow channel device having a plurality of detection ligand units, capture ligand units, absorption units, second connecting units, and third connecting units, wherein the first connecting unit includes a plurality of branching units branching downstream from a branching point, each of the plurality of branching units is connected to each of the plurality of detection ligand units, each of the plurality of detection ligand units is connected to each of the plurality of capture ligand units via the plurality of second connecting units, and each of the plurality of capture ligand units is connected to each of the plurality of absorption units via the plurality of third connecting units.

[0075] An example of a flow channel device 100 according to the second embodiment is shown in Figure 4. The liquid such as a sample added to the addition section 14 flows through a part 231a of the first connecting section, and from the branching point 401, it divides and flows through a plurality of branching sections 402, allowing the sample to be distributed to a plurality of detection ligand sections 211. Each of the plurality of detection ligand sections 211 is provided with a plurality of second connecting sections 232 that connect each of the plurality of capture ligand sections 212, and each of the plurality of capture ligand sections 212 is provided with a plurality of third connecting sections 233 that connect each of the plurality of absorption sections 15, so that multiple test substances can be detected simultaneously by dropping only one sample into the addition section 14.

[0076] This embodiment may include a backflow suppression structure, as will be described later as a seventh embodiment. A backflow suppression structure 701 may be included in a part 231a of the first connecting section. The backflow suppression structure 701 is provided so as to suppress backflow of liquid added downstream to the addition section 14 upstream. The sample added between the branching point 401 and the backflow suppression structure 701, or to the branching point 401, can be distributed to multiple parts through the branching section as described above. Subsequently, by adding a washing solution, or a liquid containing a signal generating material or signal amplifying agent, to the addition section 14, the washing solution, or the signal generating material or signal amplifying agent can be flowed into the multiple flow paths while pushing the sample flowing ahead in the multiple flow paths to the absorption section. In this way, while suppressing backflow of the sample to the upstream side, washing processes, signal generating reactions, and signal amplification reactions can be carried out sequentially and simultaneously in multiple flow paths. In other words, multi-stage reactions and multi-stage processes can be easily carried out simultaneously in multiple flow paths. The additive section 14 may have pre-placed channel cleaning material, signal generating material, signal amplifier, reaction auxiliary material, pH adjusting material, reaction stopping material, etc. By adding any solvent to dissolve these materials to the additive section 14, channel cleaning liquid, liquid containing signal generating material and signal amplifier, reaction auxiliary liquid, pH adjusting liquid, reaction stopping liquid, etc. can be generated inside the additive section 14 and flowed downstream. The backflow suppression structure 701 is not particularly limited and may have a channel shape such as a venous valve structure or a Tesla valve structure as shown in Figure 9, or materials may be arranged so as to reduce liquid permeability by filling a part of the void inside the channel. The materials are not particularly limited, but water-soluble materials such as inorganic salts, organic salts, sugars, water-soluble polymers, compositions containing them, and non-water-soluble materials such as resins can be used.

[0077] <Third Embodiment> The third embodiment provides a flow channel device having a plurality of additive portions, wherein the first connecting portion includes a plurality of branch portions that branch upstream from the branching point, and each of the plurality of additive portions is connected to each of the plurality of branch portions.

[0078] An example of a flow channel device 100 according to the third embodiment is shown in Figure 5. In Figure 5, the first connecting section 231 includes a plurality of branching sections 502 that branch upstream from the branching point 501 (in the opposite direction to the flow direction arrow), and each of the plurality of addition sections 14 is connected to each of the plurality of branching sections 502. For example, by adding a sample to the first addition section 142 and simultaneously or after a certain period of time adding a flow channel cleaning solution to the second addition section 141, the flow channel cleaning solution can be passed through the flow channel through which the sample has passed. This suppresses background signals and enables detection with high detection accuracy. When a solution containing a signal generating material is added to the third addition section 143, the signal generating reaction can be carried out in parallel or subsequently while the antigen-antibody reaction of the test substance is progressing. The inner walls 17 of some of the channel walls 12 in the branched section 502 may be coated with one of the following selected from the group consisting of albumin, PEG, PVP, PEG block copolymer, PVP block copolymer, and surfactants having PEG chains, while the inner walls 17' of the channel walls 12 in another branched section 502 may be coated with one of the following selected from the group consisting of gelatin, PVA, and PVA block copolymer. Both inner walls 17 and 17' may be coated with one of the following selected from the group consisting of albumin, PEG, PVP, PEG block copolymer, PVP block copolymer, and surfactants having PEG chains. Water-soluble materials such as inorganic salts, organic salts, sugars, water-soluble polymers or compositions containing them, and water-insoluble materials such as resins may be arranged to fill the voids inside the channel surrounded by the inner walls 17'. In this way, the speed of liquid flow can be controlled in each of the multiple branched sections 502.

[0079] <Fourth Embodiment> The fourth embodiment provides a flow path device in which the first connecting section has a first branching point and a second branching point, and multiple branching sections that branch downstream at the first branching point merge at the second branching point.

[0080] An example of a flow channel device 100 according to the fourth embodiment is shown in Figure 6. The first connecting section has a first branching point 611 and a second branching point 612, and a plurality of branching sections (branched flow channels) that branch downstream at the first branching point 611 merge at the second branching point 612. For example, by placing signal generating material or signal amplifying agent inside some of the branching sections, the liquid of the sample can be distributed, and a sample without signal generating material or signal amplifying agent and a sample containing signal generating material or signal amplifying agent can be prepared inside the flow channel, respectively. The inner wall 17 of the flow channel wall 12 of some of the branching sections is attached to one of the group consisting of albumin, PEG, PVP, PEG block copolymer, PVP block copolymer, and surfactant having a PEG chain, and the inner wall 17' of the flow channel wall 12 of another part of the branching section may be attached to one of the group consisting of gelatin, PVA, and PVA block copolymer. Both inner walls 17 and 17' may have any of the following materials attached to them: albumin, PEG, PVP, PEG block copolymer, PVP block copolymer, and surfactants having PEG chains. Water-soluble materials such as inorganic salts, organic salts, sugars, water-soluble polymers, or compositions containing them, or water-insoluble materials such as resins may be placed to fill the voids inside the flow channel surrounded by inner wall 17'. In this way, the rate of liquid flow can be controlled in each of the multiple branching sections 602.

[0081] <Fifth Embodiment> The fifth embodiment provides a flow channel device having a plurality of detection ligand units, capture ligand units, absorption units, second connecting units, and third connecting units, wherein the first connecting unit includes a plurality of branching units that branch downstream from a branching point, each of the plurality of branching units is connected to each of the plurality of detection ligand units, each of the plurality of detection ligand units is connected to each of the plurality of capture ligand units via the plurality of second connecting units, and each of the plurality of capture ligand units is connected to each of the plurality of absorption units via the plurality of third connecting units.

[0082] Figure 7 shows an example of a flow channel device 100 according to the fifth embodiment. Of the flow channels that penetrate from one of the plurality of first connecting portions 231 to one of the plurality of absorption portions 15, the inner wall 17 of the flow channel wall 12 surrounding the first flow channel 181 may be coated with any of the following: albumin, PEG, PVP, PEG block copolymer, PVP block copolymer, and surfactant having a PEG chain. The inner wall 17' of the flow channel wall 12 surrounding the second flow channel 182 may be coated with any of the following: gelatin, PVA, and PVA block copolymer. Both inner walls 17 and 17' may be coated with any of the following: albumin, PEG, PVP, PEG block copolymer, PVP block copolymer, and surfactant having a PEG chain. Water-soluble materials such as inorganic salts, organic salts, sugars, water-soluble polymers, or compositions containing them, or water-insoluble materials such as resins may be arranged to fill the voids inside the flow channels surrounded by the inner wall 17'. In this way, the flow rate of the liquid can be controlled in each of the multiple flow channels 18.

[0083] <Sixth Embodiment> The sixth embodiment provides a flow channel device in which a portion of the inner wall of the flow channel wall is attached to one selected from the group consisting of gelatin, PVA, and PVA block copolymer, and another portion is attached to one selected from the group consisting of albumin, PEG, PVP, PEG block copolymer, PVP block copolymer, and surfactant having a PEG chain.

[0084] <Seventh Embodiment> The seventh embodiment provides a flow channel device in which the first connecting portion has a backflow suppression structure. An example of the flow channel device 100 according to the seventh embodiment is shown in Figure 9. The first connecting portion has a backflow suppression structure 701 and a second additive portion 142, and the backflow suppression structure 701 is connected to the first additive portion 141 and the second additive portion 142 on the upstream side of the second additive portion 142. The inner wall 17 of the flow channel wall 12 is coated with one of the following selected from the group consisting of albumin, PEG, PVP, PEG block copolymer, PVP block copolymer, and surfactant having PEG chains. Liquid such as a sample added to the second additive portion 142 flows more in part 231b of the first connecting portion than in part 231a of the first connecting portion, thereby suppressing backflow to the upstream side. Subsequently, by adding a washing solution or a liquid containing a signal generating material or signal amplifying agent to the first additive portion 141, the sample that has flowed through the flow channel ahead can be pushed to the absorption portion. In this way, backflow to the upstream side can be suppressed while the washing process, signal generation reaction, and signal amplification reaction can be carried out in a sequential manner. In other words, multi-stage reactions and multi-stage processes can be easily implemented.

[0085] The first additive section 141 may have pre-placed flow path cleaning material, signal generating material, signal amplifier, reaction auxiliary material, pH adjusting material, reaction stopping material, etc. By adding any solvent to dissolve these materials to the first additive section 141, flow path cleaning liquid, liquid containing signal generating material and signal amplifier, reaction auxiliary liquid, pH adjusting liquid, reaction stopping liquid, etc. can be generated inside the first additive section 141 and flowed downstream. The backflow suppression structure 701 is not particularly limited and may have a flow path shape such as a venous valve structure or a Tesla valve structure as shown in Figure 9, or materials may be arranged so as to reduce liquid permeability by filling a part of the void inside the flow path. The material is not particularly limited, but water-soluble materials such as inorganic salts, organic salts, sugars, water-soluble polymers, compositions containing them, and non-water-soluble materials such as resins can be used.

[0086] <Eighth Embodiment> The flow path device may be a combination of multiple parts. The multiple parts may be stacked, or parts may be overlapped and joined together. The eighth embodiment provides a flow path device in which a second flow path device having a connecting part for connecting the flow paths of multiple flow path devices, and a third flow path device having an additive part and a flow path, are connected to the first flow path device. An example of the flow path device 100 according to the eighth embodiment is shown in Figures 10A to 10C. Figure 10A is a top view of the flow path device 100, Figure 10B is a view of each device constituting the flow path device 100, and Figure 10C is a cross-section of the dashed line section C-C' shown in Figure 10A. In Figures 10A to 10C, in the flow path device 1002, the connecting part 801 and the connecting part 802 are provided separately, and the flow path device 1003 has an additive part 14' and a flow path 18'. The connecting portion 801 connects the additive portion 14 and the additive portion 14', and the connecting portion 802 connects the flow path 18 and the flow path 18'. The flow path device 1002 is placed between the flow path device 1001 and the flow path device 1003 and superimposed to form the flow path device 100. The liquid added to the additive portion is distributed and flows through the connecting portion into the flow path 18 of the flow path device 1001 and the flow path 18' of the flow path device 1003, and merges at the point where the connecting portion 802 connects them. In other words, the liquid can be distributed and merged perpendicular to the substrate surface.

[0087] The inner wall 17 of the channel wall 12 of the channel device 1001 is attached to any of the group consisting of albumin, PEG, PVP, PEG block copolymer, PVP block copolymer, and surfactant having PEG chains. The inner wall 17'' of the channel wall 12'' of the channel device 1002 and the inner wall 17' of the channel wall 12' of the channel device 1003 may be attached to any of the group consisting of gelatin, PVA, and PVA block copolymer. The inner walls 17, 17', and 17'' may all be attached to any of the group consisting of albumin, PEG, PVP, PEG block copolymer, PVP block copolymer, and surfactant having PEG chains. Water-soluble materials such as inorganic salts, organic salts, sugars, water-soluble polymers, compositions containing them, and water-insoluble materials such as resins may be arranged to fill the voids inside the channel surrounded by the inner wall 17'. In this way, the flow rate of the liquid can be controlled in both channel 18 and channel 18'. The liquid passing first through channel 18 allows the antigen-antibody reaction to proceed first, while the liquid delayed through channel 18' can wash the ligand portion. Furthermore, by placing signal generating material or signal amplifying agent in channel 18', a solution containing the signal generating material or signal amplifying agent can be prepared inside channel 18' and then flowed to the ligand portion. By providing a connection point upstream of the ligand portion, washing, signal generating reactions, and signal amplification reactions can be carried out in a sequential manner. In other words, multi-stage reactions and multi-stage processes can be easily implemented.

[0088] <Ninth Embodiment> The ninth embodiment provides a flow channel device in which a first flow channel device having a flow channel and an absorption section is connected to a second flow channel device having an additive section, a branching point, and a branching section. An example of the flow channel device 100 according to the ninth embodiment is shown in Figures 11A and 11B. Figure 11A is a top view of the flow channel device 100, and Figure 11B shows each device (part) that constitutes the flow channel device 100. In Figures 11A and 11B, the flow channel device 1001 has a flow channel 18 and an absorption section 15, and the flow channel device 1002 has an additive section 14, a branching point 401, and a plurality of branching sections 402. The flow channel device 100 is formed by connecting them so that one branching section 402 is in contact with the flow channel 18.

[0089] The liquid added to the additive section 14 is distributed and flows into multiple branch sections 402 through the branching point. After flowing from the branch section 402 connected to the flow path 18 into the flow path 18, the connection between the flow path 18 and the branch section 402 is disconnected, and the flow path device 1002 is moved to reconnect so that the branch section 402' is in contact with the flow path 18, thereby allowing the liquid to flow from the branch section 402' into the flow path 18. In other words, by connecting the flow paths of multiple flow path devices, the flow paths can be switched by moving the flow path device. The inner wall 17 of the flow path wall 12 of the flow path device 1001 is attached to one of the group consisting of albumin, PEG, PVP, PEG block copolymer, PVP block copolymer, and surfactant having PEG chains, and the inner wall 17' of the flow path wall 12' of the flow path device 1002 may be attached to one of the group consisting of gelatin, PVA, and PVA block copolymer. Both the inner wall 17 and the inner wall 17' may have any of the following adhering to it: albumin, PEG, PVP, PEG block copolymer, PVP block copolymer, and surfactants having PEG chains. Water-soluble materials such as inorganic salts, organic salts, sugars, water-soluble polymers, or compositions containing them, or water-insoluble materials such as resins may be placed to fill the voids in the branched section 402'. After the liquid flowing in from the branched section 402 is passed through to generate an antigen-antibody reaction, the flow path 18 can be cleaned by passing the liquid flowing in from the branched section 402'. Furthermore, if a signal generating material or a signal amplifying agent is placed inside the branched section 402', a liquid containing the signal generating material or signal amplifying agent will flow from the branched section 402' into the flow path 18. By moving the flow path device, cleaning processes, signal generating reactions, and signal amplification reactions can be generated in a sequential manner. In other words, multi-stage reactions and multi-stage processes can be easily implemented.

[0090] <Tenth Embodiment> The flow path device may also include other parts. The tenth embodiment provides a flow path device having a liquid holding member, a member that expands when it absorbs liquid, and a support 921. An example of the flow path device 100 according to the tenth embodiment is shown in Figures 12A and 12B. Figure 12A is a top view of the flow path device 100, and Figure 12B is a cross-sectional view showing the cross section B-B' shown by the dashed line in Figure 12A. In Figures 12A and 12B, the member that expands when it absorbs water is in contact with the back of the flow path 18 of the flow path device, and the liquid holding member 901 is positioned above the flow path device, away from the flow path device, using the support 921. When a portion of the liquid added to the additive section 14 flows through the flow path 18, it is absorbed by the member 911 on the back of the flow path 18. The member expands, and the entire or a part of the flow path device 1001 deforms, causing the flow path device to come into contact with the liquid holding member. In other words, after the sample is introduced into the flow path, the flow path device comes into contact with the liquid-holding member as the components and flow path device deform, allowing the liquid held in the liquid-holding member to flow into the flow path. The inner wall 17 of the flow path wall 12 is coated with one of the following selected from the group consisting of albumin, PEG, PVP, PEG block copolymer, PVP block copolymer, and surfactant having PEG chains. The sample and the liquid held in the liquid-holding member can be introduced sequentially and quickly, allowing for easy implementation of multi-stage reactions and multi-stage processes. The liquid-holding member may contain materials such as flow path cleaning material, signal generating material, signal amplifying agent, reaction auxiliary material, pH adjusting material, and reaction stopping material. The liquid-holding member may also contain a flow path cleaning solution, a liquid containing a signal generating material or signal amplifying agent, a reaction auxiliary solution, a pH adjusting solution, and a reaction stopping solution.

[0091] <Eleventh Embodiment> The eleventh embodiment provides a flow channel device having a storage section and a liquid-permeable member. An example of the flow channel device 100 according to the eleventh embodiment is shown in Figures 13A and 13B. Figure 13A is a top view of the flow channel device 100, and Figure 13B shows a cross-section of the dashed line section B-B' shown in Figure 13A. In Figures 13A and 13B, the flow channel device 1004 has a storage section 1101 separated from the flow channel 16. It also has a liquid-permeable member 931 separate from the flow channel device 1004. A flow channel cleaning solution, a liquid containing a signal generating material or signal amplifying agent, a reaction auxiliary solution, a pH adjusting solution, a reaction stopping solution, etc. are added to the storage section 1101, and a sample is added to the addition section 14. After that, the liquid-permeable member 931 is placed in contact with the storage section 1101 and the addition section 14, so that the liquid added to the storage section flows into the flow channel 18. The inner wall 17 of the flow channel wall 12 is coated with one of the following selected from the group consisting of albumin, PEG, PVP, PEG block copolymer, PVP block copolymer, and surfactant having PEG chains. The sample and the liquid held in the liquid holding member can be flowed sequentially and quickly, and multi-stage reactions and multi-stage processes can be easily carried out. The inner wall 17 may be coated with one of the following selected from the group consisting of albumin, PEG, PVP, PEG block copolymer, PVP block copolymer, and surfactant having PEG chains, or it may be coated with one of the following selected from the group consisting of gelatin, PVA, and PVA block copolymer.

[0092] The present disclosure will be described in further detail below using examples and comparative examples, but the disclosure is not limited to these.

[0093] [Example 1] <Substrate / Flow Channel> The substrate of the flow channel device 100 will be described using Figure 8. Figure 8 is a simplified top view of the flow channel device 100 before the arrangement of various ligands.

[0094] In this embodiment, qualitative filtration cellulose filter paper (Whatman® Grade 1) was used as the porous substrate 11. The fine voids between the cellulose fibers allow for capillary action and also possess good hydrophilicity, functioning as a channel through which liquids can penetrate smoothly. A hydrophobic resin was impregnated into a portion of this porous substrate 11 to form a channel wall 12 with a height H1 = 16 mm and a width L1 = 45 mm. The channel wall 12 was formed by printing a hydrophobic resin (a styrene-acrylic resin obtained by polymerizing a composition containing styrene, n-butyl acrylate, and divinylbenzene) as a toner onto qualitative filtration cellulose filter paper using an electrophotographic method, and then melting and impregnating the resin by heating, as described in Japanese Patent Application Publication No. 2021-37612. The hydrophobic resin in Example 1 is as described above, but the hydrophobic resin is not limited to this.

[0095] Furthermore, within the inner region of the channel wall 12, there is an area where the hydrophobic resin that forms the channel wall has not permeated, and this region becomes the channel region 16 using the porosity of the porous substrate 11. The channel region 16 consists of an absorption section 15, an additive section 14, and a channel 18 with a width of 4 mm and a length of 24 mm that connects the absorption section 15 to the additive section 14.

[0096] In the flow path 18, a detection ligand 3211 was positioned 2 mm from the addition section 14 to form a detection ligand section 211, and a capture ligand 3212 was fixed 10 mm from the addition section 14 to form a capture ligand section 212. This formed a first connecting section 231 connecting the addition section 14 and the detection ligand section 211, a second connecting section 232 connecting the detection ligand section 211 and the capture ligand section 212, and a third connecting section 233 connecting the capture ligand section 212 and the absorption section 15. The absorption section 15 was a 12 mm square, and the addition section 14 was a 5 mm square. The size and shape of the flow path 18 in Example 1 are as described above, but the size and shape of the flow path 18 are not limited to these.

[0097] <Capture Ligand Section> 1 μL of a 0.025% nitrocellulose solution with ethyl acetate as the solvent was applied to the capture ligand section 212 using a pen (DAISO, DIY pen kit) and dried.

[0098] As the capture ligand 3212, we used the Mouse Anti-Human CRP Capture Antibody included with Human C-Reactive Protein / CRP DuoSet ELISA, 15 Plate (manufactured by R&D Systems, Inc., DY1707).

[0099] In the coating step for the capture ligand 3212, a Mouse Anti-Human CRP Capture Antibody solution, adjusted to a concentration of 360 μg / mL by dissolving it in Tris-buffered saline (pH 7.6, hereafter TBS), was applied to the capture ligand portion 212 using a pen (DAISO, handmade pen kit) and dried. This was repeated twice. The resulting fluidic device 100 was designated as fluidic device M1, and it was immersed in TBS containing 0.05% Tween 20 for 5 minutes (twice), and then immersed in TBS for 5 minutes. This immobilized the capture ligand 3212 on the capture ligand portion 212.

[0100] Furthermore, although the capture ligand 3212 was applied using a pen-based application method in this embodiment, the method is not limited to this, and may also be performed using an inkjet method, a dispenser, or a stamp. Compared to the pen-based application method, the inkjet method, dispenser, and stamp can apply the solution quantitatively and uniformly in a line, so the capture ligand 3212 can be applied to the capture ligand section 212 with high precision, and the capture ligand section 212, which serves as the judgment line, can be accurately positioned as in a typical immunochromatographic method.

[0101] <Albumin Adhesion> Fluid device M1 was immersed in TBS containing 1% bovine serum albumin (Sigma-Aldrich, A9418) at 25°C for 75 minutes. After immersion in TBS for 5 minutes, it was dried at room temperature. This allowed albumin to adhere to the inner wall 17 of the fluid channel wall 12. Note that immersion of fluid device M1 is not essential; albumin can also be adhered to the inner wall 17 of the fluid channel wall 12 by wetting the entire fluid channel with albumin solution, or by applying it to the interface between the fluid channel wall 12 and the fluid channel using an inkjet method or dispenser. Fluid device M1 was immersed in Coomassie brilliant blue solution for 10 minutes and then washed overnight with pure water, which resulted in staining of fluid device M1 and confirmation of albumin adhesion to the inner wall 17 of the fluid channel wall 12.

[0102] <Flow Rate> 20 μL of TBS was added to the addition section 14 of the flow channel device M1, which had albumin attached, and the time it took for the TBS to reach the absorption section 15 was measured. The flow rate of TBS was calculated from the length of the flow channel 18. The flow rate of TBS was 13.6 mm / min.

[0103] <Detection Ligand Section> 1 μL of TBS solution containing 20% ​​sucrose and 0.25% Tween 20 was applied to the detection ligand section 211 and dried. This was repeated twice. As the detection ligand 3211, Mouse Anti-human C-reactive Protein Monoclonal Antibody (manufactured by Oriental Yeast Co., Ltd., 47858000), which was modified with alkaline phosphatase using Alkaline Phosphatase Labeling Kit-NH2 (Dojin Chemical Laboratories Co., Ltd., LK12), was used. In the application step for the detection ligand 3211, 1 μL of a detection ligand solution, adjusted to a concentration of 14 μg / mL using a TBS solution containing 20% ​​sucrose and 0.25% Tween 20, was applied to the detection ligand section 211 using a micropipette and dried. This placed the detection ligand 3211 on the detection ligand section 211. In this embodiment, the detection ligand 3211 was applied using a micropipette, but the method is not limited to this, and other methods such as an inkjet method, dispenser, or stamp may also be used. Inkjet methods, dispensers, and stamps can apply the solution faster and more quantitatively than the micropipette method, so the detection ligand 3211 can be applied to the detection ligand section 211 with high accuracy.

[0104] <Detection> Recombinant Human C-reactive Protein (manufactured by Oriental Yeast Co., Ltd., 47191000, hereinafter referred to as rhCRP) was used as the test substance to detect rhCRP.

[0105] 20 μL of rhCRP solution, adjusted to a concentration of 50 ng / mL using TBS containing 1% by mass BSA, was added dropwise to the detection ligand section 211 using a micropipette and allowed to stand at room temperature for 5 minutes. A cotton ball (5 mm square) soaked in a BCIP / NBT-containing buffer solution (pH 9.5) prepared using SIGMAFAST® BCIP® / NBT (Sigma-Aldrich, B5655) was brought into contact with the addition section 14. After standing at room temperature for 15 minutes, the flow channel device M1 was washed with pure water.

[0106] After drying the flow channel device M1, a color image of the flow channel device M1 was acquired using a scanner (CanoScan LiDE400, Canon Inc.). The color intensity emitted from the capture ligand section 212 was quantified using Image J software. Seven flow channel devices M1 were fabricated and evaluated similarly, and the average color intensity of the capture ligand section 212 was calculated. The color intensity of the capture ligand section 212 was 62.5. The coefficient of variation for the color intensity of the capture ligand section 212 was 6.1%.

[0107] [Example 2] The TBS solution containing 20% ​​sucrose and 0.25% Tween 20 used in the <detection ligand portion> of Example 1 was replaced with a TBS solution containing 20% ​​sucrose, 0.25% Tween 20, and 2% BSA, and the procedure was carried out in the same manner as in Example 1. The color intensity of the capture ligand portion 212 was 60.4. The coefficient of variation of the color intensity of the capture ligand portion 212 was 6.1%.

[0108] [Example 3] The TBS solution containing 20% ​​sucrose and 0.25% Tween 20 used in the <detection ligand portion> of Example 1 was replaced with a TBS solution containing 2% Tween 20 and 10% BSA, and the procedure was carried out in the same manner as in Example 1. The color intensity of the capture ligand portion 212 was 76.0. The coefficient of variation for the color intensity of the capture ligand portion 212 was 3.0%.

[0109] [Example 4] The TBS solution containing 20% ​​sucrose and 0.25% Tween 20 used in the <detection ligand portion> of Example 1 was replaced with a TBS solution containing 0.5% Tween 20 and 10% BSA, and the procedure was carried out in the same manner as in Example 1. The color intensity of the capture ligand portion 212 was 79.2. The coefficient of variation of the color intensity of the capture ligand portion 212 was 1.6%.

[0110] [Example 5] The TBS solution containing 20% ​​sucrose and 0.25% Tween 20 used in the <detection ligand portion> of Example 1 was replaced with a TBS solution containing 2% Tween 80 and 10% BSA, and the procedure was carried out in the same manner as in Example 1. The color intensity of the capture ligand portion 212 was 80.6. The coefficient of variation for the color intensity of the capture ligand portion 212 was 9.0%.

[0111] [Example 6] The TBS solution containing 20% ​​sucrose and 0.25% Tween 20 used in the <detection ligand portion> of Example 1 was replaced with a TBS solution containing 2% Triton X-100 and 10% BSA, and the procedure was carried out in the same manner as in Example 1. The color intensity of the capture ligand portion 212 was 75.7. The coefficient of variation for the color intensity of the capture ligand portion 212 was 4.4%.

[0112] [Example 7] The TBS solution containing 20% ​​sucrose and 0.25% Tween 20 used in the <detection ligand portion> of Example 1 was replaced with a TBS solution containing 2% Brij 35 and 10% BSA, and the procedure was carried out in the same manner as in Example 1. The color intensity of the capture ligand portion 212 was 82.4. The coefficient of variation for the color intensity of the capture ligand portion 212 was 3.6%.

[0113] [Example 8] The TBS solution containing 20% ​​sucrose and 0.25% Tween 20 used in the <detection ligand portion> of Example 1 was replaced with a TBS solution containing 2% CHAPS and 10% BSA, and the procedure was carried out in the same manner as in Example 1. The color intensity of the capture ligand portion 212 was 72.6. The coefficient of variation of the color intensity of the capture ligand portion 212 was 7.3%.

[0114] [Example 9] The TBS solution containing 20% ​​sucrose and 0.25% Tween 20 used in the <detection ligand portion> of Example 1 was replaced with a TBS solution containing 0.25% Tween 20 and 10% PVP K30, and the procedure was carried out in the same manner as in Example 1. The color intensity of the capture ligand portion 212 was 72.1. The coefficient of variation of the color intensity of the capture ligand portion 212 was 6.3%.

[0115] [Example 10] The TBS containing 1% bovine serum albumin used in <Albumin Adhesion> of Example 1 was replaced with a TBS containing 1% Triton X-100, and the procedure was carried out in the same manner as in Example 1. The TBS flow rate was 12.6 mm / min. The color intensity of the capture ligand portion 212 was 75.5. The coefficient of variation of the color intensity of the capture ligand portion 212 was 3.1%.

[0116] [Example 11] The TBS solution containing 20% ​​sucrose and 0.25% Tween 20, which was used in the <detection ligand portion> of Example 1, was replaced with the TBS solution, and the procedure was carried out in the same manner as in Example 1. The color intensity of the capture ligand portion 212 was 36.7. The coefficient of variation of the color intensity of the capture ligand portion 212 was 23.4%.

[0117] [Reference Example 1] The detection in Example 1 was performed using the same method as in Example 1, but with the concentration of 50 ng / mL replaced with 0 ng / mL. The color intensity of the capture ligand portion 212 was 6.5. The coefficient of variation for the color intensity of the capture ligand portion 212 was 22.3%. It was possible to rapidly detect that the sample did not contain the test substance.

[0118] [Comparative Example 1] The same procedure as in Example 1 was used, but with casein instead of albumin. The TBS flow rate was 11.8 mm / min. The color intensity of the captured ligand portion 212 was 50.9. The coefficient of variation of the color intensity of the captured ligand portion 212 was 8.9%.

[0119] [Comparative Example 2] The procedure was carried out in the same manner as in Example 1, but without performing the albumin attachment step. The flow rate of TBS was 10.9 mm / min. The color intensity of the captured ligand portion 212 was 54.5. The coefficient of variation of the color intensity of the captured ligand portion 212 was 5.9%.

[0120] [Comparative Example 3] <Substrate / Flow Channel> In this comparative example, qualitative filtration cellulose filter paper (Whatman Grade 1) cut to a size of 4 mm in width and 41 mm in length was used without forming the flow channel wall 12.

[0121] To position the detection ligand 3211 and the capture ligand 3212 at the same location as in the flow channel device M1, the detection ligand section was set 7 mm from one end and the capture ligand section 212 was set 15 mm from one end, creating a flow channel device without a flow channel wall 12, which was designated as the flow channel device M2.

[0122] The procedure was carried out in the same manner as in Example 1, but with the flow channel device M1 of Example 1 replaced with the flow channel device M2. The flow velocity of the TBS was 11.4 mm / min. The color intensity of the capture ligand portion 212 was 35.3. The coefficient of variation of the color intensity of the capture ligand portion 212 was 9.7%.

[0123] [Comparative Example 4] The flow path device M1 of Example 1 was replaced with the flow path device M2, and the albumin deposition step was omitted, and the procedure was carried out in the same manner as in Example 1. The flow velocity of the TBS was 11.6 mm / min.

[0124] Table 1 shows the results for the above examples, comparative examples, and reference examples, as well as the examples, comparative examples, and reference examples described later, including the presence or absence of flow path walls in each device, the adhering material, the additives, and the flow velocity, color intensity, and coefficient of variation.

[0125] As described above, when using the flow channel device according to the embodiment of this disclosure, a high color intensity was obtained after a certain period of time. This is because the test substance and signal generating material flowed rapidly, and the antigen-antibody reaction and color reaction started early. The higher the color intensity after a certain period of time, the sooner the color intensity necessary for detecting the test substance can be obtained, and thus the test substance can be measured rapidly. In other words, it was found that when using the flow channel device according to the embodiment of this disclosure, the flow velocity in the flow channel region can be promoted, the antigen-antibody reaction and color reaction can be performed rapidly, and the target object can be measured rapidly.

[0126] [Example 12] <Substrate / Flow Channel> The substrate of the flow channel device 100 will be described using Figure 14. Figure 14 is a simplified top view of the flow channel device 100 before the arrangement of various ligands.

[0127] In this embodiment, a cellulose filter paper for qualitative filtration (Whatman® Grade 4) was used as the porous substrate 11. A hydrophobic resin was impregnated into a portion of this porous substrate 11 to form a channel wall 12 with a height H1 = 16 mm and a width L1 = 45 mm. The channel wall 12 was formed by printing a hydrophobic resin (a styrene-acrylic resin obtained by polymerizing a composition containing styrene, n-butyl acrylate, and divinylbenzene) as a toner onto the cellulose filter paper for qualitative filtration using an electrophotographic method, and then melting and impregnating the resin by heating, as described in Japanese Patent Application Publication No. 2021-37612. The hydrophobic resin in Example 12 is as described above, but the hydrophobic resin is not limited to this.

[0128] Furthermore, within the region inside the channel wall 12, there is an area where the hydrophobic resin that forms the channel wall has not permeated, and this region becomes the channel region 16 using the porous material 11. The channel region 16 consists of an absorption section 15, a first branching point 611, a second branching point 612, a branching section 602, an additive section 14, and a channel 18 with a width of 3 mm and a length of 16 mm that connects the absorption section 15 to the second branching point 612.

[0129] The branch section 602 is a flow path with a width of 6 mm and a length of 7 mm, and consists of a branch section 602a with a width of 2 mm and a length of 7 mm that is coaxial with the absorption section 15, two flow path walls 12' with a width of 1 mm and a length of 7 mm that sandwich the branch section 602a, and a branch section 602b that is sandwiched between flow path walls 12 and 12' and is parallel to the two branch sections 602a with a width of 1 mm and a length of 7 mm. The branch section 602a and the two branch sections 602b connect from the first branch point 611 to the second branch point 612. In the flow path 18, a detection ligand 3211 is placed at a position 12 mm from the absorption section 15 to set up a detection ligand section 211, and a capture ligand 3212 is fixed at a position 4 mm from the absorption section 15 to set up a capture ligand section 212. A first connecting portion 231 is formed to connect the detection ligand portion 211, a second connecting portion 232 is formed to connect the detection ligand portion 211 and the capture ligand portion 212, and a third connecting portion 233 is formed to connect the capture ligand portion 212 and the absorption portion 15.

[0130] In other words, the first connecting section 231 has a connecting section 231a that connects to a first branching point 611, branching sections (branching channels) 602a and 602b, a second branching point 612, and a ligand section 211. The branching sections that branch downstream from the first branching point 611, which is connected to the absorption section, merge at the second branching point 612, and connect to the connecting section 231a, the detection ligand section 211, and the capture ligand section 212. The absorption section 15 was a 12 mm square, and the addition section 14 was a rectangle with a width of 6 mm and a length of 4 mm. Although the size and shape of the channel 18 in Example 4 are as described above, the size and shape of the channel 18 are not limited to these.

[0131] <Capture Ligand Section> The fluid channel device 100 fabricated using the same method as in Example 1 was designated as fluid channel device M3.

[0132] <Albumin attachment> This was carried out using the same method as in Example 1.

[0133] <Detection Ligand Section> This was carried out using the same method as in Example 1.

[0134] <Signal Generating Material Coating> 10 mg of SIGMAFAST® BCIP® / NBT (Sigma-Aldrich, B5655) was dissolved in 75 μL of 0.25% Tween 20 aqueous solution. 0.5 μL of the prepared BCIP / NBT-containing buffer solution was applied to the branch section 602a and dried. This was repeated five times.

[0135] <Detection> 50 μL of rhCRP solution, adjusted to a concentration of 1 μg / mL using TBS containing 1% by mass BSA, was added dropwise to a cotton ball (3 mm square) placed on top of the addition section 14 using a micropipette. The liquid that passed through the branch section 602b, which was not coated with BCIP / NBT, reached the branch point 612 earlier than the liquid that passed through the branch section 602a, which was coated with BCIP / NBT. After standing at room temperature for 20 minutes following the addition of the rhCRP solution, the flow channel device M3 was washed with pure water. After drying the flow channel device M3, a color image of the flow channel device M3 was acquired using a scanner (CanoScan LiDE400, Canon Inc.). The color intensity emitted from the capture ligand section 212 was quantified using Image J software. Three flow channel devices M3 were fabricated and each was evaluated in the same manner, and the average color intensity of the capture ligand portion 212 was calculated. The color intensity of the capture ligand portion 212 was 64.2. The coefficient of variation for the color intensity of the capture ligand portion 212 was 8.6%.

[0136] [Comparative Example 5] The procedure was carried out in the same manner as in Example 12, but without performing the albumin attachment step. The color intensity of the captured ligand portion 212 was 55.8.

[0137] [Reference Example 2] The rhCRP solution adjusted to a concentration of 1 μg / mL used in the detection step of Example 12 was replaced with an rhCRP solution adjusted to a concentration of 0 μg / mL, and the procedure was carried out in the same manner as in Example 1. The color intensity of the capture ligand portion 212 was 7.8. The coefficient of variation for the color intensity of the capture ligand portion 212 was 63.9%. It was possible to rapidly detect that the sample did not contain the test substance.

[0138] As described above, when using the flow path device according to the embodiment of this disclosure, by placing the signal generating material inside a part of the branch section 602b, the flow velocity of the liquid passing through the branch section 602b was reduced compared to the flow velocity of the liquid passing through the branch section 602a. As a result, the sample passing through the branch section 602a passed through the detection ligand section and the capture ligand section first, allowing the antigen-antibody reaction to be carried out rapidly. Subsequently, the sample passing through the branch section 602b rapidly transferred the signal generating material to the capture ligand section, and the color reaction was carried out. In other words, the antigen-antibody reaction and the color reaction could be carried out continuously and rapidly simply by adding the sample. Furthermore, a high color intensity was obtained after a certain period of time. The higher the color intensity after a certain period of time, the faster the color intensity necessary for detecting the test substance can be obtained, thus enabling rapid measurement of the test substance. In other words, it was found that when using the flow channel device according to the embodiment of this disclosure, the flow velocity in the flow channel region can be increased, and by adjusting the flow velocity in a part of the flow channel region, antigen-antibody reactions and color reactions can be performed continuously simply by adding a sample, and the target object can be measured rapidly.

[0139] [Example 13] <Substrate / Flow Channel> The substrate of the flow channel device 100 will be described using Figure 15. Figure 15 is a simplified top view of the flow channel device 100 before the arrangement of various ligands. In this example, qualitative filtration cellulose filter paper (Whatman® Grade 1) was used as the porous substrate 11. A hydrophobic resin was impregnated into a part of this porous substrate 11 to form a flow channel wall 12 with a height H1 = 16 mm and a width L1 = 55 mm. The flow channel wall 12 was formed by printing a hydrophobic resin (styrene-acrylic resin obtained by polymerizing a composition containing styrene, n-butyl acrylate, and divinylbenzene) as a toner onto qualitative filtration cellulose filter paper using an electrophotographic method, and then heating to melt and impregnate the resin, as described in Japanese Patent Application Publication No. 2021-37612. The hydrophobic resin in Example 13 is as described above, but the hydrophobic resin is not limited to this.

[0140] Furthermore, within the region inside the channel wall 12, there is a region where no channel wall is formed, and this region becomes a channel region 16 using the porous material 11. The channel region 16 consists of an absorption section 15, an additive section 14, and a channel 18 with a width of 4 mm and a length of 33 mm that connects the absorption section 15 to the additive section 14.

[0141] A backflow suppression structure 701 was set in the flow path 18 at a position adjacent to the additive section 14. Although liquids such as samples can pass through the backflow suppression structure 701, the permeability is reduced. A backflow suppression structure 701 with a width of 4 mm and a length of 1.5 mm was formed by printing a smaller amount of resin per unit area than that used to form the flow path wall 12, and then heating to melt and permeate the resin.

[0142] The detection ligand 3211 was positioned 2 mm from the addition section 14 to form the detection ligand section 211, and the capture ligand 3212 was fixed 10 mm from the addition section 14 to form the capture ligand section 212. This formed a first connecting section 231 connecting the addition section 14 and the detection ligand section 211, a second connecting section 232 connecting the detection ligand section 211 and the capture ligand section 212, and a third connecting section 233 connecting the capture ligand section 212 and the absorption section 15. The backflow suppression structure 701 was positioned in the area of ​​the first connecting section 231. The absorption section 15 was a 12 mm square, and the addition section 14 was a 5 mm square. Although the size and shape of the flow path 18 in Example 13 are as described above, the size and shape of the flow path 18 are not limited to these.

[0143] <Capture Ligand Section> The fluid channel device 100 fabricated using the same method as in Example 1 was designated as the fluid channel device M4.

[0144] <Albumin Adhesion> The procedure was carried out in the same manner as in Example 1, but with the concentration of bovine serum albumin set to 3%.

[0145] <Detection Ligand Section> This was carried out using the same method as in Example 4.

[0146] <Detection> 20 μL of rhCRP solution, adjusted to a concentration of 50 ng / mL using TBS containing 1% by mass BSA, was added dropwise to the detection ligand section 211 using a micropipette. After 3 seconds, a cotton ball (5 mm square) soaked in BCIP / NBT-containing buffer solution (pH 9.5) was brought into contact with the addition section 14. After standing at room temperature for 20 minutes, the flow channel device M4 was washed with pure water. The color intensity emitted from the capture ligand section 212 was quantified in the same manner as in Example 1. Seven flow channel devices M4 were prepared and evaluated in the same manner, and the average value of the color intensity of the capture ligand section 212 was calculated. The color intensity of the capture ligand section 212 was 77.8. The coefficient of variation for the color intensity of the capture ligand section 212 was 4.4%.

[0147] [Reference Example 3] The rhCRP solution used in the detection step of Example 13 was changed from a concentration of 50 ng / mL to 0 ng / mL, and the procedure was carried out in the same manner as in Example 13. The color intensity of the capture ligand portion 212 was 7.6. The coefficient of variation for the color intensity of the capture ligand portion 212 was 14.9%. It was possible to rapidly detect that the sample did not contain the test substance.

[0148] [Reference Example 4] The flow channel device M4 of Example 13 was replaced with M1, and the procedure was carried out in the same manner as in Example 13. The color intensity of the capture ligand portion 212 was 51.4. The coefficient of variation of the color intensity of the capture ligand portion 212 was 17.5%.

[0149] [Reference Example 5] The flow channel device M4 of Example 13 was replaced with M1, and the 50 ng / mL concentration used for detection in Example 13 was replaced with a 0 ng / mL concentration, and the procedure was carried out in the same manner as in Example 13. The color intensity of the capture ligand portion 212 was 4.7. The coefficient of variation of the color intensity of the capture ligand portion 212 was 11.8%.

[0150] [Example 14] The <substrate / channel>, <capture ligand section>, <albumin attachment>, and <detection ligand section> were carried out in the same manner as in Example 13. <Signal generating material coating> 10 mg of SIGMAFAST® BCIP® / NBT (Sigma-Aldrich, B5655) was dissolved in 75 μL of pure water. 1 μL of the prepared BCIP / NBT-containing buffer solution was coated onto the addition section 14 of the channel device M4 of Example 13 and dried. This was repeated 6 times.

[0151] <Detection> The procedure of contacting the addition section 14 with cotton wool (5 mm square) soaked in the BCIP / NBT-containing buffer solution (pH 9.5) of Example 13 was replaced with the procedure of dropping 20 μL of pure water onto the addition section 14 using a micropipette, and the procedure was carried out in the same manner as in Example 13. The color intensity of the capture ligand section 212 was 70.1. The coefficient of variation of the color intensity of the capture ligand section 212 was 5.9%.

[0152] Thus, when using the flow channel device according to the embodiment of this disclosure, high color intensity was obtained even when a liquid containing the signal generating material, or a solvent for dissolving the signal generating material placed in the device, was added without delay after the sample was added, thanks to the arrangement of the backflow suppression structure. This is because the added sample flowed rapidly downstream with backflow to the upstream side suppressed, and was pushed from upstream to the absorption section by the liquid containing the signal generating material, allowing the antigen-antibody reaction and the color reaction to occur in a sequential and rapid manner.

[0153] Furthermore, the higher the color intensity after a certain period of time, the faster the color intensity necessary for detecting the test substance can be obtained, thus enabling rapid measurement of the test substance. In other words, it has been found that when using the flow channel device according to the embodiment of this disclosure, the flow velocity in the flow channel region can be promoted, and the test substance and signal generating material can be flowed in a sequential and rapid manner, allowing the antigen-antibody reaction and color reaction to be performed simply and continuously, and enabling rapid measurement of the object to be measured.

[0154] According to this disclosure, the flow velocity of the liquid flowing through the channel of a fluid channel device for analyzing a test substance can be improved.

[0155] This disclosure is not limited to the embodiments described above, and various modifications and alterations are possible without departing from the spirit and scope of this disclosure. Accordingly, the following claims are attached to make the scope of this disclosure public.

[0156] This application claims priority based on Japanese Patent Application No. 2024-168101, filed on 27 September 2024, and Japanese Patent Application No. 2025-031763, filed on 28 February 2025, and all of the contents of those applications are incorporated herein by reference.

[0157] 100 Flow channel device 11 Porous substrate 12 Flow channel wall 15 Absorption section 14 Addition section 17 Inner wall 16 Flow channel region 18 Flow channel 21 Ligand section 211 Detection ligand section 212 Capture ligand section 23 Connecting section 231 First connecting section 232 Second connecting section 233 Third connecting section

Claims

1. A flow channel device for analyzing a test substance, having a flow channel region surrounded by a flow channel wall provided inside a porous substrate, wherein the flow channel region includes an addition section for adding liquid, a ligand section for which a ligand is provided, an absorption section into which the liquid flows, and a connecting section connecting any two selected from the group consisting of the addition section, the ligand section, and the absorption section, the ligand is a substance that specifically binds to the test substance, and at least a part of the inner wall of the flow channel wall is attached to any one selected from the group consisting of albumin, PEG, PVP, PEG block copolymer, PVP block copolymer, and a surfactant having a PEG chain.

2. The channel device according to claim 1, wherein the channel wall comprises a thermoplastic resin.

3. The flow channel device according to claim 1 or 2, wherein the porous substrate has a heat resistance temperature of 140°C or higher.

4. The flow channel device according to any one of claims 1 to 3, wherein albumin is attached to at least a portion of the inner wall of the flow channel wall.

5. The flow path device according to any one of claims 1 to 4, further comprising a liquid-holding member that can hold liquid and release the liquid into the flow path when brought into contact with the additive portion.

6. The flow channel device according to any one of claims 1 to 5, wherein the test substance is selected from the group consisting of syphilis treponema antibody, hepatitis C virus antibody, hepatitis B virus surface antigen, human immunodeficiency virus antigen, human immunodeficiency virus antibody, influenza antigen, and C-reactive protein.

7. The flow channel device according to any one of claims 1 to 6, wherein the flow channel region includes a backflow suppression structure.

8. The flow path device according to claim 7, wherein the backflow suppression structure has a hydrophobic resin attached to it and is permeable to liquid.

9. The flow channel device according to claim 7, characterized in that the backflow suppression mechanism includes a hydrophobic resin, and the fluid permeability of the flow channel region is lower than that of the region outside the backflow suppression mechanism.

10. The flow channel device according to any one of claims 1 to 9, wherein the ligand portion includes a detection ligand portion for which a detection ligand is arranged, and a capture ligand portion in which a capture ligand is fixed inside a porous substrate, and the connecting portion includes a first connecting portion connecting the addition portion and the detection ligand portion, a second connecting portion connecting the detection ligand portion and the capture ligand portion, and a third connecting portion connecting the capture ligand portion and the absorption portion.

11. The flow channel device according to claim 10, wherein the detection ligand is disposed inside or on top of the detection ligand portion.

12. The flow channel device according to claim 10, wherein the detection ligand is disposed in the ligand portion together with any of the following: a mixture of sugar and surfactant, a mixture of sugar, surfactant and albumin, a mixture of albumin and surfactant, and a mixture of albumin and sugar.

13. The flow channel device according to claim 10, wherein the detection ligand is modified with a labeled molecule.

14. The flow channel device according to claim 13, wherein the labeled molecule is an enzyme and the liquid contains a substrate for the enzyme.

15. A flow channel device having a plurality of detection ligand units, capture ligand units, absorption units, second connecting units, and third connecting units, wherein the first connecting unit includes a plurality of branching units branching downstream from a branching point, each of the plurality of branching units is connected to each of the plurality of detection ligand units, each of the plurality of detection ligand units is connected to each of the plurality of capture ligand units via the plurality of second connecting units, and each of the plurality of capture ligand units is connected to each of the plurality of absorption units via the plurality of third connecting units, as described in claim 10.

16. A flow channel device having a plurality of additive portions, wherein the first connecting portion includes a plurality of branch portions branching upstream from a branching point, and each of the plurality of additive portions is connected to each of the plurality of branch portions, as described in claim 10.

17. The flow path device according to claim 10, wherein the first connecting portion has a first branching point and a second branching point, and a plurality of branching portions that branch downstream at the first branching point merge at the second branching point.

18. The flow channel device according to claim 17, wherein the plurality of branching sections include branching sections on which any of the following are disposed: a flow channel cleaning material, a signal generating material, a signal amplifying agent, a reaction assisting material, a pH adjusting material, and a reaction stopping material.

19. The flow channel device according to any one of claims 15 to 18, characterized in that one of the following is attached to the inner wall of the flow channel wall of some of the branching sections among the plurality of branching sections: gelatin, PVA, and PVA block copolymer.

20. A flow channel device having a plurality of detection ligand units, capture ligand units, absorption units, first connecting units, second connecting units, and third connecting units, wherein the addition unit is connected to the plurality of detection ligand units via the plurality of first connecting units, each of the plurality of detection ligand units is connected to each of the plurality of capture ligand units via the plurality of second connecting units, and each of the plurality of capture ligand units is connected to each of the plurality of absorption units via the plurality of third connecting units, as described in claim 10.

21. A flow channel device according to any one of claims 1 to 20, comprising a plurality of parts.

22. The flow channel device according to claim 21, wherein the plurality of parts are stacked.

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