Sheet-like structure

Abstract

This sheet-like structure has a porous structure layer including: a flow path having a porous structure through which a fluid can flow; and a non-flow path through which the fluid does not flow. The flow path has a fluid receiving part, a flow path part, and a detection part. The fluid receiving part, the flow path part, and the detection part can be connected in the stated order to circulate the fluid. A ratio (CFTd / CFTf) of a capillary flow time CFTd of the detection part to a capillary flow time CFTf of the flow path part is 1.2 or more.

Description

Sheet-like structure

[0001] The present invention relates to a sheet-like structure.

[0002] Development of testing devices that enable simple and rapid diagnosis in everyday life and clinical settings is progressing. Pregnancy tests are a typical example of such testing devices. When a test liquid containing a target substance such as an antigen is introduced into the testing device, the test liquid flows through a flow path within the testing device. Then, a labeling medium such as an antibody pre-loaded in the flow path reacts with the target substance in the test liquid, causing a color (color development), allowing the presence of the target substance to be confirmed.

[0003] Test chips, which are an example of test devices, are sometimes called "μ-PADs (microfluidic paper-based analytical devices)" and have many advantages, such as (1) low cost, (2) pumpless, (3) no need for large-scale equipment, and (4) easy disposal, and research into improving them is being conducted worldwide.

[0004] Various test chips (test devices) have already been reported, and for example, a test chip has been proposed in which a three-dimensional flow path is formed in a single sheet-like material in order to significantly suppress uneven color development (see Patent Document 1). Furthermore, for the purpose of producing a test chip simply and at low cost, a method has been reported in which the outer edges of the flow paths and reaction spots described above are printed on paper with ultraviolet-curable ink and then cured by irradiating the ink with ultraviolet light (see Patent Document 2).

[0005] JP 2021-175970 A International Publication No. 2012 / 160857

[0006] However, in the conventional test chip described in Patent Document 1, although the fluid flow rate is controlled by the flow path design, such as the width of the liquid flow path, the fluid flow rate is so fast that the flow rate cannot be suppressed by changing the flow direction due to the stacked three-dimensional flow paths, and color unevenness cannot be sufficiently suppressed, leaving room for improvement. Furthermore, in the conventional test chip described in Patent Document 2, color unevenness is likely to occur, which may result in variability in the test results (insufficient reproducibility). For example, there is a problem in which color development occurs near the edge of the detection area, making it difficult to visually observe.

[0007] The present invention aims to solve the above-mentioned problems in the prior art and to achieve the following object: That is, the present invention aims to provide a sheet-like structure that maintains the rapidity of the reaction, has uniform color development, and has improved quantitative accuracy.

[0008] The means for solving the above problems are as follows: <1> A porous structure layer having a flow path with a porous structure through which a fluid can flow and a non-flow path through which the fluid does not flow, wherein the flow path has a fluid receiving section, a flow path section, and a detection section, wherein the fluid receiving section, the flow path section, and the detection section are connected in this order to allow the fluid to flow, and wherein the capillary flow time (CFT) of the flow path section is ｆ The capillary flow time CFT of the detection unit ｄ Ratio to (CFT ｄ / CFT ｆ <2> The capillary flow time (CFT) of the flow channel portion is 1.2 or more. ｆ The capillary flow time CFT of the detection unit ｄ The ratio of (CFT ｄ / CFT ｆ <3> The sheet-like structure according to <1>, wherein the capillary flow time (CFT) of the flow channel portion is 1.2 or more and 2.9 or less. ｆ <4> The sheet-like structure according to <1> or <2>, wherein the capillary flow time (CFT) of the detection unit is 120 seconds / 4 cm or less. ｄThe sheet-like structure according to any one of <1> to <3>, wherein the non-channel is formed by impregnating the porous structure with a hydrophobic material. <5> The sheet-like structure according to any one of <1> to <4>, wherein the non-channel is formed by impregnating the porous structure with a hydrophobic material. <6> The sheet-like structure according to any one of <1> to <5>, wherein the channel has the fluid receiving section and the channel section communicating with the first surface and the second surface of the porous structure layer, and the detection section communicating with the first surface and not exposed on the second surface. <7> The sheet-like structure according to <6>, wherein the detection section has a support layer on the second surface, or the porous structure on the second surface of the detection section is impregnated with a hydrophobic material. <8> The sheet-like structure according to <6> or <3>, further having a support layer on the second surfaces of the fluid receiving section and the channel section. <9> The sheet-like structure according to <8>, wherein the support layer is water-impermeable. <10> The sheet-like structure according to any one of <1> to <9>, which is an inspection device.

[0009] According to the present invention, it is possible to provide a sheet-like structure that maintains the rapidity of the reaction, develops uniform color, and has improved quantitative accuracy.

[0010] FIG. 1 is a schematic perspective view showing a manufacturing process of a sheet-like structure of a first embodiment. FIG. 2 is a schematic plan view of the front and back surfaces of a sheet-like structure of the first embodiment. FIG. 3 is a schematic cross-sectional view of a sheet-like structure of the first embodiment. FIG. 4 is a schematic perspective view showing a manufacturing process of a sheet-like structure of a second embodiment. FIG. 5 is a schematic cross-sectional view of the front and back surfaces of a sheet-like structure of the second embodiment. FIG. 6 is a schematic cross-sectional view of a sheet-like structure of the second embodiment. FIG. 7 is a schematic cross-sectional view of a sheet-like structure of a third embodiment. FIG. 8 is a schematic perspective view showing a manufacturing process of a sheet-like structure of a fourth embodiment. FIG. 9 is a schematic plan view of the front and back surfaces of a sheet-like structure of the fourth embodiment. FIG. 10 is a schematic cross-sectional view of a sheet-like structure of the fourth embodiment. FIG. 11 is a schematic plan view of the front and back surfaces of a sheet-like structure of a fifth embodiment. FIG. 12 is a schematic plan view of the front and back surfaces of a sheet-like structure of a sixth embodiment. FIG. 13 is a schematic plan view of the front and back surfaces of a sheet-like structure of a seventh embodiment. Fig. 14 is a schematic plan view of the front and back surfaces of a sheet-like structure of an eighth embodiment. Fig. 15 is a schematic view showing a flow path pattern 1 in an example. Fig. 16 is a schematic view showing a non-flow path pattern 1 in an example. Fig. 17 is a schematic view showing a flow path pattern 2 in an example. Fig. 18 is a schematic view showing a non-flow path pattern 2 in an example. Fig. 19 is a schematic perspective view showing a manufacturing process of a sheet-like structure in comparative example 1.

[0011] (Sheet-like structure) The sheet-like structure of the present invention has a porous structure layer having a flow path with a porous structure through which a fluid can flow and a non-flow path through which the fluid does not flow, and the flow path has a fluid receiving section, a flow path section, and a detection section, and the fluid receiving section, the flow path section, and the detection section are connected in this order to allow the fluid to flow. ｆ The capillary flow time CFT of the detection unit ｄ Ratio to (CFT ｄ / CFT ｆ ) is 1.2 or more. The sheet-like structure can be suitably used as a testing device.

[0012] [Capillary flow time] The ratio (CFT ｄ / CFT ｆ ) is 1.2 or more, and from the viewpoint of uniformity of color development, it is preferably 1.2 or more and 5 or less, more preferably 1.2 or more and 2.9 or less, and from the viewpoint of further improving the rapidity of the reaction, it is even more preferably 1.2 or more and 2.0 or less.

[0013] Capillary flow time (CFT) of the flow channel ｆ From the viewpoint of reaction speed, the speed is preferably 120 seconds / 4 cm or less, more preferably 110 seconds / 4 cm or less, and even more preferably 100 seconds / 4 cm or less. From the viewpoint of ensuring reaction time, the speed is preferably 80 seconds / 4 cm or more, more preferably 90 seconds / 4 cm or more, and even more preferably 100 seconds / 4 cm or more.

[0014] Here, the ratio (CFT ｄ / CFT ｆ The flow path portion for defining the flow path may be at least a part of the flow path portion in the sheet-like structure, or may be the entire flow path portion. For example, as in the sheet-like structure shown in FIGS. 1 to 3 described later, the sheet-like structure may have a plurality of flow paths B to D, and in addition, the CFT of each flow path may be ｆ If the CFT of the flow path is different, ｆ When the ratio (CFT ｄ / CFT ｆ ) is satisfied, and the entire flow path portion ｄ / CFT ｆ Among these, the entire flow path portion may satisfy the ratio (CFT ｄ / CFT ｆ ) is preferably satisfied.

[0015] Capillary flow time (CFT) of the detection section ｄFrom the viewpoint of reaction speed, the speed is preferably 300 seconds / 4 cm or less, more preferably 250 seconds / 4 cm or less, and even more preferably 200 seconds / 4 cm or less. From the viewpoint of color uniformity, the speed is preferably 100 seconds / 4 cm or more, more preferably 150 seconds / 4 cm or more, and even more preferably 200 seconds / 4 cm or more.

[0016] The capillary flow time (CFT) is the time it takes for 4 cm of pure water to be drawn up when one end of a sample such as a filter paper is placed in pure water. ｆ ), the capillary flow time (CFT) of the detection section ｄ ), CFT ｆ CFT for ｄ The ratio of (CFT ｄ / CFT ｆ ) can be evaluated.

[0017] (1) Prepare a test sheet-like structure in the shape of a strip of 1 cm x 6 cm for each of the flow path section and the detection section as a test specimen. (2) Immerse the end of the test sheet-like structure vertically in pure water, and measure the time required for the pure water to be absorbed by 4 cm. (3) Measure multiple specimens (e.g., n = 3) to calculate the average value, and use the average value obtained as the capillary flow time (CFT) of the flow path section. ｆ ), and the capillary flow time (CFT) of the detection section ｄ ) Also, CFT ｆ CFT for ｄ The ratio of (CFT ｄ / CFT ｆ ) is calculated.

[0018] The sheet-like structure is a desired CFT. ｆ , CFT ｄ , and the ratio (CFT ｄ / CFT ｆFrom the viewpoint of having a porous structure layer having a first surface and a second surface, it is preferable that the flow path has the fluid receiving portion and the flow path portion communicating with the first surface and the second surface of the porous structure layer, and the detection portion communicating with the first surface and not exposed on the second surface. Here, the detection portion may be (1) a support layer on the second surface of the detection portion, or (2) a porous structure on the second surface of the detection portion impregnated with a hydrophobic material (i.e., a non-flow path is formed on the second surface side of the detection portion), as long as it is communicated with the first surface of the porous structure layer and not exposed on the second surface. Either of these may be suitably selected. Note that one surface of the porous structure layer will be referred to as the "first surface" or "front surface," and the surface opposite the first surface will be referred to as the "second surface" or "rear surface." However, the use of these terms is intended to facilitate understanding of the invention with reference to the drawings, and the technical scope of the present invention is not limited by the meanings of these terms.

[0019] In addition, the flow path portion may be a desired CFT. ｆ In view of the above, the fluid receiving portion is preferably in communication with the first and second surfaces of the porous structure layer, and may be (1) in an embodiment in which a support layer is not provided and the first and second surfaces of the porous structure layer are exposed, or (2) in an embodiment in which a support layer is provided on the second surface of the flow path portion (i.e., the second surface of the flow path portion is not exposed), either of which can be suitably selected. Similarly to the flow path portion, the fluid receiving portion is preferably in communication with the first and second surfaces of the porous structure layer, and may be (1) in an embodiment in which a support layer is not provided and the first and second surfaces of the porous structure layer are exposed, or (2) in an embodiment in which a support layer is provided on the second surface of the fluid receiving portion (i.e., the second surface of the fluid receiving portion is not exposed), either of which can be suitably selected. The support layer is preferably impermeable.

[0020] The present invention will be described in detail below based on several embodiments, but the present invention is not limited to the following description in any way.

[0021] <First Aspect> A sheet-like structure 11 of the first aspect will be specifically described with reference to FIGS. 1 to 3. FIG. 1 is a schematic perspective view showing a manufacturing process for the sheet-like structure of the first aspect. FIG. 2 is a schematic plan view of the front and back surfaces of the sheet-like structure of the first aspect. FIG. 3 is a schematic cross-sectional view of the sheet-like structure of the first aspect. The sheet-like structure 11 of the first aspect shown in FIGS. 1 to 3 has a porous structure layer 101 having a flow path X having a porous structure through which a fluid can flow and a non-flow path Y through which a fluid does not flow. The flow path X has a fluid receiving section A, flow path sections B, C, and D, and a detection section E. The fluid receiving section A, the flow path sections B, C, and D, and the detection section E are connected in this order to allow the fluid to flow. The fluid receiving section A and the flow path sections B, C, and D are in communication with the front and back surfaces of the porous structure layer 101. The sheet-like structure 11 further has a support layer 301 so as to cover the back surface of the detection unit E, and the back surface side of the detection unit E is not exposed. By having such a configuration, the sheet-like structure 11 can maintain the flow rate of the fluid in the flow channel portion to maintain the rapidity of the reaction, while maintaining the ratio (CFT ｄ / CFT ｆ ) can be made 1.2 or more, the coloring can be made uniform, and the quantitative accuracy can be improved.

[0022] The method for producing the sheet-like structure 11 is not particularly limited and can be appropriately selected depending on the purpose. For example, the sheet-like structure 11 can be suitably produced by the production process shown in FIG. 1 . As schematically shown in FIG. 1 , a material M having a porous structure is impregnated from both sides with a hydrophobic material m lacking a flow path pattern of a flow path X and having a non-flow path Y pattern. This produces a porous structure layer 101 having a non-flow path Y formed from a material M′ obtained by impregnating the material M with the hydrophobic material m. The flow paths A to E are formed from the material M having a porous structure, and the non-flow path Y is formed from a material M′ obtained by impregnating the material M with the hydrophobic material. Next, a support layer 301 is disposed on the back surface of the porous structure layer 101 so as to cover the back surface of the detection unit E, thereby producing the sheet-like structure 11 of the first embodiment.

[0023] -Porous Structure Layer- The porous structure layer 101 in the sheet-like structure 11 is provided with a flow path X having a porous structure through which a fluid can flow by capillary action or the like, and a non-flow path Y in an area other than the flow path X. The flow path X has a fluid receiving section A, flow path sections B, C, and D, and a detection section E, and the fluid receiving section A, the flow path sections B, C, and D, and the detection section E are connected in this order to allow the fluid to flow.

[0024] Here, the term "fluid" is not particularly limited as long as it can flow through the flow path of the porous structure by capillary action or the like, and can be appropriately selected depending on the purpose. When the sheet-like structure of the present invention is applied to a testing device, examples include a specimen suspected of containing a substance to be detected, and a solution containing a specimen and a reaction reagent. Examples of the reaction reagent include a medium that reacts with the substance to be detected, and a labeling medium that causes a color reaction due to the substance to be detected. The viscosity of the fluid is not particularly limited as long as it allows the fluid to flow through the flow path of the porous structure, and can be appropriately adjusted depending on the purpose.

[0025] The fluid receiving section A is a section into which the fluid is dropped. The detection section E is a section where the presence or absence of a detection target substance such as an antigen in the fluid dropped into the fluid receiving section A is confirmed by the presence or absence of color development. The reaction reagent may be contained in the fluid, or may be placed on the flow path of the sheet-like structure. For example, the reaction reagent can be placed in the flow path section C of the sheet-like structure 11. Note that although flow path sections B to D with different flow path widths and shapes are provided in FIGS. 1 to 3, an integrated flow path section with a constant flow path width may also be provided.

[0026] Here, the term "porous structure" refers to a structure having a plurality of interconnected pores, and is generally also referred to as a co-continuous structure or a monolith structure. The porous structure has continuously connected pores that spread three-dimensionally, allowing fluid to penetrate (i.e., capillary action). The cross-sectional shape of the pores in the porous structure can be appropriately set in consideration of the physical properties of the fluid, such as viscosity, and examples include a substantially circular shape, a substantially elliptical shape, and a substantially polygonal shape. The size of the pores in the porous structure is not particularly limited and can be appropriately selected depending on the purpose. The cross-sectional shape and size of the pores can be determined, for example, from a cross-sectional photograph taken with a scanning electron microscope (SEM) or the like.

[0027] The porosity of the porous structure can be appropriately set taking into account the physical properties such as the viscosity of the fluid. The method for measuring the porosity is not particularly limited, but for example, a method can be used in which the porous structure is filled with unsaturated fatty acid (commercially available butter), osmium stained, the internal cross-sectional structure is cut out with an FIB, and the porosity is measured using a scanning electron microscope (SEM) or the like. The distribution of pores in the porous structure can be appropriately set taking into account the physical properties such as the viscosity of the fluid as long as the fluid can flow through it, but it is preferable that the pores are distributed uniformly within the flow path region.

[0028] The shape of the flow channel X in a plan view is not particularly limited and can be selected appropriately depending on the purpose as long as it allows fluid to flow therethrough, and examples thereof include circular, elliptical, square, rectangular, etc. The diameter (or major axis) of the flow channel X is not particularly limited and can be selected appropriately depending on the purpose, and can be, for example, 3 mm or more and 10 mm or less. The flow channel width of the flow channel sections B to D is not particularly limited and can be selected appropriately depending on the purpose, and can be, for example, 1 mm or more and 5 mm or less.

[0029] The material M of the flow path X is not particularly limited as long as it has a porous structure that allows fluid to flow through it, and can be appropriately selected depending on the purpose, and examples thereof include paper such as filter paper, nonwoven fabric, nitrocellulose, polypropylene, etc. Among these, filter paper is more preferable from the viewpoint of simplicity and low cost.

[0030] The non-channel Y refers to the region other than the channel X in the porous structure layer, i.e., the region where fluid flow is not achieved. The material M' for the non-channel Y is not particularly limited and can be appropriately selected depending on the purpose as long as it does not achieve fluid flow. For example, it can be obtained by impregnating the material M with a hydrophobic material m. From the viewpoint of ease of manufacturing the porous structure layer, the hydrophobic material preferably has a melting point of 90°C or less, and examples thereof include wax or a composition containing the same. In addition to the hydrophobic material, the composition can appropriately contain viscosity adjusting components such as resins, dispersing aids, fillers, etc.

[0031] When the hydrophobic material is impregnated into the material M of the flow path, it is preferable to heat and melt the hydrophobic material. The heating temperature can be appropriately set taking into account the melting points of the hydrophobic material and the viscosity adjusting component. The viscosity of the hydrophobic material when melted can be appropriately set taking into account the average thickness and basis weight (density) of the porous structure layer so that the hydrophobic material can be impregnated into the porous structure layer as desired.

[0032] When the material M of the flow path is impregnated with a hydrophobic material, the impregnation rate of the hydrophobic material relative to the material M is preferably 14% or more and 32% or less. By manufacturing a porous structure layer so that the impregnation rate is 14% or more, the wall surface of the flow path (the interface between the material M and the material M') becomes sufficiently uniform, and for example, the flow of fluid from the flow path to the flow path can be made smoother. Furthermore, by manufacturing a porous structure layer so that the impregnation rate is 32% or less, problems such as blockages that occur when the hydrophobic material is impregnated into the material M can be sufficiently avoided, and a porous structure layer having a desired flow path structure can be more reliably obtained.

[0033] Here, "impregnation rate" refers to the proportion of material M' in the region containing material M' throughout the entire thickness direction of the porous structure layer, where 100% impregnation rate (maximum impregnation amount) is defined as the state in which material M is saturated with the hydrophobic material. The state in which material M is saturated with the hydrophobic material (maximum impregnation amount) is determined appropriately depending on the combination of material M and the hydrophobic material. For example, material M' obtained by impregnating material M with a hydrophobic material that has been heated to a sufficiently low viscosity (e.g., heated to 120°C), maintaining the temperature, and leaving it for a sufficient time (e.g., 3 minutes) can be considered to have a 100% impregnation rate. The impregnation rate can be adjusted, for example, by adjusting the amount of hydrophobic material to be impregnated (e.g., the thickness of the composition containing the hydrophobic material).

[0034] The method for measuring the impregnation rate of the hydrophobic material into the material M is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include the following methods. [Method for measuring impregnation rate] A filter paper was cut into a size of 5 cm x 2 cm, dried at 120°C for 3 minutes, and then the dry mass M ０ Next, the dried filter paper is immersed in a hydrophobic material and left at 120°C for 3 minutes. After immersion, the filter paper is sandwiched between the same type of filter paper and a slide glass, and left at 120°C for 1 minute under a load of 100 gf to remove excess hydrophobic material. After that, the mass M of the filter paper is measured. １ (g) was measured, and the maximum impregnation amount per unit area P was calculated using the following formula (1). ｍａｘ (g / m ２ ) is calculated. ｍａｘ (g / m ２ ) = (M １ -M ０ )×1000...Formula (1)

[0035] Next, the amount of hydrophobic material impregnated in the material M (g / m) was measured. ２ ) is calculated, and the impregnation rate is calculated by the following formula (2): Impregnation rate (%) = (P / P ｍａｘ )×100...Formula (2)

[0036] The viscosity of the composition containing the hydrophobic material is not particularly limited and can be appropriately selected depending on the purpose. For example, from the viewpoint of sufficiently avoiding problems such as clogging when impregnating the material M, the viscosity of the composition containing the hydrophobic material may be selected at 140° C. and a shear rate of 3000 s －１ The viscosity is preferably 100 mPa s or less, more preferably 50 mPa s or less, and even more preferably 30 mPa s or less. There are no particular limitations on the method for measuring the viscosity, and the viscosity can be measured using, for example, a rheometer (for example, AR-G2 Rheometer, product name, manufactured by TA Instruments).

[0037] Material M' is preferably colored to allow easy visual confirmation of the flow of fluid, but may be white, transparent, or uncolored. Coloring of material M' can be achieved, for example, by impregnating material M with a colorant in addition to the hydrophobic material. Examples of the colorant include pigments such as carbon black (black pigment), and are preferably hydrophobic. Furthermore, it is preferable to select a colorant that does not adversely affect reagents used in testing, etc.

[0038] The shape of the porous structure layer 101 in plan view is not particularly limited and can be appropriately selected depending on the purpose. Examples include a rectangle, a substantially circle, a substantially oval, and a substantially rectangle.

[0039] - Support Layer - The sheet-like structure 11 has a support layer 301. The support layer 301 is provided so as to cover the second surface of the detection unit E of the sheet-like structure 11. Since the second surface of the detection unit E is not exposed, the capillary flow time CFT of the detection unit ｄ The capillary flow time CFT of the flow channel sections B to D ｆ , and the desired ratio (CFT ｄ / CFT ｆ The support layer 301 also has the function of reinforcing the physical strength of the sheet-like structure 11 itself.

[0040] The material of the support layer 301 is not particularly limited and can be set appropriately depending on the purpose, but is preferably non-permeable, such as polypropylene, etc. The size, structure, and shape of the support layer 301 are not particularly limited as long as they can cover the flow path in the porous structure layer, and can be set appropriately depending on the purpose.

[0041] A commercially available product can also be used as the support layer 301. An example of such a commercially available product is 660-PF (manufactured by Nichiban Co., Ltd.).

[0042] The average thickness of the sheet-like structure 11 is not particularly limited and can be appropriately selected depending on the purpose, and can be, for example, 100 μm or more and 300 μm or less. The average thickness can be measured using a thickness meter (e.g., ID-C112BS, manufactured by Mitutoyo Corporation). The size of the sheet-like structure 11 is not particularly limited and can be appropriately selected depending on the purpose.

[0043] <Second Aspect> In the first aspect, the detection unit E that is not exposed on the second surface is covered with the support layer 301. However, as in the second to fourth aspects described below, the porous structure on the second surface of the detection unit E may be impregnated with a hydrophobic material. In other words, the sheet-like structure may have a non-flow path on the second surface side of the detection unit E. The following mainly describes configurations that differ from the first aspect. Regarding matters common to the first aspect, matters described in the first aspect can be selected as appropriate.

[0044] Here, the sheet-like structure 12 of the second embodiment will be specifically described with reference to FIGS. 4 to 6. FIG. 4 is a schematic perspective view showing a manufacturing process of the sheet-like structure of the second embodiment. FIG. 5 is a schematic plan view of the front and back surfaces of the sheet-like structure of the second embodiment. FIG. 6 is a schematic cross-sectional view of the sheet-like structure of the second embodiment. The sheet-like structure 12 of the second embodiment shown in FIGS. 4 to 6 has a porous structure layer 102 having a flow path X with a porous structure through which a fluid can flow and a non-flow path Y through which a fluid does not flow. The flow path X has a fluid receiving section A, flow path sections B, C, and D, and a detection section E. The fluid receiving section A, the flow path sections B, C, and D, and the detection section E are connected in this order to allow the fluid to flow. The fluid receiving section A and the flow path sections B, C, and D are in communication with the front and back surfaces of the porous structure layer 102. The sheet-like structure 12 further has a porous structure 20 on the back surface of the detection unit E impregnated with a hydrophobic material, has a non-flow path on the second surface side of the detection unit E, and the back surface side of the detection unit E is not exposed. By having such a configuration, the sheet-like structure 12 can maintain the flow rate of the fluid in the flow path part and maintain the rapidity of the reaction while reducing the ratio (CFT ｄ / CFT ｆ ) can be made 1.2 or more, the coloring can be made uniform, and the quantitative accuracy can be improved.

[0045] The method for manufacturing the sheet-like structure 12 is not particularly limited and can be appropriately selected depending on the purpose. For example, the sheet-like structure 12 can be suitably manufactured by the manufacturing process shown in FIG. 4 . As schematically shown in FIG. 4 , a material M having a porous structure is impregnated from both sides of the material M with a hydrophobic material m lacking a flow path pattern of flow path X and having a non-flow path Y pattern, thereby obtaining a porous structure layer 102 having a non-flow path Y formed thereon, which is made of a material M′ impregnated with the hydrophobic material m. Here, the shape of the hydrophobic material m for the front surface is different from the shape of the hydrophobic material m for the back surface. The hydrophobic material m for the front surface has a non-flow path pattern lacking the flow path patterns of flow paths A to E, while the hydrophobic material m for the back surface has a non-flow path pattern lacking only the flow path patterns of flow paths A to D. This allows the porous structure 20 on the back surface of the detection unit E to be impregnated with the hydrophobic material, thereby manufacturing a sheet-like structure 12 of a second embodiment having a non-flow path on the second surface side of the detection unit E.

[0046] 6, the tip region when the hydrophobic material is impregnated from the front surface of the porous structure layer 102 is depicted by a dotted imaginary line. This imaginary line is also the tip region when the hydrophobic material is impregnated from the back surface of the porous structure layer 102, and is also the boundary between the two. The front surface side of the porous structure layer 102, separated by this imaginary line, is referred to as the porous structure 10, and the back surface side of the porous structure layer 102 is referred to as the porous structure 20. The imaginary line is depicted in the same way in other drawings.

[0047] In the sheet-like structure 12, the ratio (t2 / t1) of the average thickness (t2) of the porous structure 20 to the average thickness (t1) of the porous structure 10 is approximately 1. The sheet-like structure 12 having such a configuration can be suitably manufactured by making the average thickness of the hydrophobic material m for the front surface and the average thickness of the hydrophobic material m for the back surface approximately equal in the manufacturing process shown in FIG.

[0048] <Third Aspect> In the second aspect, the ratio (t2 / t1) of the average thickness (t2) of the porous structure 20 to the average thickness (t1) of the porous structure 10 is approximately 1. However, as in the third aspect described below, the ratio (t2 / t1) may be changed. The following mainly describes configurations that differ from the second aspect. Regarding matters common to the first and second aspects, the matters described above can be selected as appropriate.

[0049] The sheet-like structure 13 of the third embodiment will be specifically described with reference to Figures 4 to 5 and Figure 7. The sheet-like structure 13 of the third embodiment shown in Figure 7 differs from the sheet-like structure 12 of the second embodiment in that the ratio (t2 / t1) of the average thickness (t2) of the porous structure 20 to the average thickness (t1) of the porous structure 10 is less than 1. Note that the schematic plan views of the front and back surfaces of the sheet-like structure of the third embodiment are the same as those of the second embodiment shown in Figure 5.

[0050] The method for manufacturing the sheet-like structure 13 is not particularly limited and can be appropriately selected depending on the purpose. For example, in the manufacturing process of the second embodiment shown in Figure 4, the sheet-like structure 13 can be suitably manufactured by adjusting the ratio between the average thickness of the hydrophobic material m for the front surface and the average thickness of the hydrophobic material m for the back surface.

[0051] The ratio (t2 / t1) is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 0.56 or more and 2.2 or less. By manufacturing a sheet-like structure so that the ratio (t2 / t1) is 0.56 or more and 2.2 or less, problems such as clogging when impregnating the material M with the hydrophobic material m can be sufficiently avoided, and for example, the flow rate and / or rate stability of the liquid from the flow channel A to the flow channel D can be effectively increased. Furthermore, in the second and third aspects, the ratio (CFT ｄ / CFT ｆ From the viewpoint of increasing the ratio (t2 / t1) to improve the uniformity of color development, the ratio (t2 / t1) is preferably 0.6 or more, more preferably 0.8 or more, and even more preferably 1.0 or more. The ratio (t2 / t1) is not particularly limited, and can be 3.0 or less.

[0052] <Fourth Aspect> As shown in the sheet-like structure 14 of the fourth aspect, the sheet-like structure 12 of the second aspect may further have a support layer 304 on the entire back surface of the porous structure layer 104. The following mainly describes the configuration different from the second aspect. Regarding the matters common to the first to third aspects, the matters described above can be appropriately selected.

[0053] The sheet-like structure 14 of the fourth embodiment will be specifically described with reference to FIGS. 8 to 10 . FIG. 8 is a schematic perspective view showing a manufacturing process for the sheet-like structure of the fourth embodiment. FIG. 9 is a schematic plan view of the front and back surfaces of the sheet-like structure of the fourth embodiment. FIG. 10 is a schematic cross-sectional view of the sheet-like structure of the fourth embodiment. The sheet-like structure 14 of the fourth embodiment shown in FIGS. 8 to 10 has a porous structure layer 104 having a flow path X with a porous structure through which a fluid can flow and a non-flow path Y through which a fluid does not flow. The flow path X has a fluid receiving section A, flow path sections B, C, and D, and a detection section E. The fluid receiving section A, the flow path sections B, C, and D, and the detection section E are connected in this order to allow the fluid to flow. The fluid receiving section A and the flow path sections B, C, and D are in communication with the front and back surfaces of the porous structure layer 104. The sheet-like structure 14 has a porous structure 20 on the back surface of the detection unit E impregnated with a hydrophobic material, and has a non-flow path on the second surface side of the detection unit E. The sheet-like structure 14 further has a support layer 304 on the entire back surface of the porous structure layer 104, and the back surfaces of the fluid receiving unit A and flow path units B, C, and D are not exposed. By having such a configuration, the sheet-like structure 14 can maintain the rapidity of the reaction while ensuring the reaction time of the fluid in the fluid receiving unit A and flow path units B, C, and D, and can achieve a ratio (CFT ｄ / CFT ｆ ) can be set to 1.2 or more, which makes the color development uniform and improves the accuracy of quantification. Furthermore, the support layer 304 can reinforce the physical strength of the sheet-like structure 14 itself. Furthermore, contamination of the fluid flowing through the flow channel can be prevented. For example, when the fluid is a specimen and a reagent (e.g., an antigen and an antibody, etc.), this is preferable because it can prevent reaction inhibition due to contamination.

[0054] The method for manufacturing the sheet-like structure 14 is not particularly limited and can be appropriately selected depending on the purpose. For example, the sheet-like structure 14 can be suitably manufactured by the manufacturing process shown in FIG. 8 . As schematically shown in FIG. 8 , a material M having a porous structure is impregnated from both sides of the material M with a hydrophobic material m having a different pattern of non-channel Y for the front surface and a pattern of non-channel Y for the back surface. This impregnates the porous structure 20 on the back surface of the detection unit E with the hydrophobic material, thereby obtaining a porous structure layer 104 having non-channels on the second surface side of the detection unit E. The channels A to E are formed from the material M having a porous structure, and the non-channel Y is formed from a material M′ obtained by impregnating the material M with the hydrophobic material. Next, a support layer 304 is disposed on the back surface of the porous structure layer 104 so as to cover the back surfaces of the fluid receiving unit A and the channel units B, C, and D, thereby manufacturing the sheet-like structure 14 of the fourth embodiment.

[0055] In the fourth embodiment, the support layer 304 is disposed on the entire back surface of the porous structure layer 104, but this embodiment is not limited to this. The region where the support layer 304 is disposed is not particularly limited and can be appropriately selected depending on the purpose. It may be only the back surface of the fluid receiving portion A, only the back surfaces of the flow path portions B, C, and D, or the back surface of all or any part of the flow path. In addition, the ratio (CFT ｄ / CFT ｆ ) 1.2 or more is satisfied, an additional support layer 304' may be placed on the surface of the porous structure layer 104, and the region where the support layer 304' is placed may be a non-channel surface so that the channels A to D are exposed, or may include the surface of any of the channel portions B, C, and D.

[0056] <Fifth Aspect to Eighth Aspect> A plurality of flow paths may be provided as in the fifth to eighth aspects described below. Below, the fifth to eighth aspects in which a plurality of flow paths are provided based on the second aspect will be described, but in each of the first aspect and the third to fourth aspects, a plurality of flow paths may be provided instead of a single flow path, and the features common to the first to fourth aspects can be selected as appropriate from the features described above.

[0057] Fig. 11 is a schematic plan view of the front and back surfaces of a sheet-like structure of the fifth embodiment. As shown in Fig. 11, the sheet-like structure 15 of the fifth embodiment is similar to the second embodiment shown in Figs. 4 to 6 except that it has a plurality of flow path sections F (two flow path sections F1 and F2 in Fig. 11). Here, in Fig. 11, flow path sections F having a substantially constant flow path width are provided, but flow path sections B to D having different flow path widths and shapes may be provided instead of each flow path section F, as in the first to fourth embodiments.

[0058] Fig. 12 is a schematic plan view of the front and back surfaces of a sheet-like structure according to a sixth embodiment. As shown in Fig. 12, the sheet-like structure 16 according to the sixth embodiment is generally similar to Fig. 11 except that it has a structure having three flow path sections F (F3 in addition to F1 and F2). In the sheet-like structure 16 shown in Fig. 12, the three flow path sections F are connected to the detection section E so as to face each other.

[0059] Fig. 13 is a schematic plan view of the front and back surfaces of a sheet-like structure 17 of the seventh embodiment. As shown in Fig. 13, the sheet-like structure 17 of the seventh embodiment is generally similar to Fig. 12 except that the flow path section F3 is branched into two (F31 and F32) and connected to the detection section E.

[0060] Fig. 14 is a schematic plan view of the front and back surfaces of a sheet-like structure of the eighth embodiment. As shown in Fig. 14, the sheet-like structure 18 of the eighth embodiment is generally similar to Fig. 11 except that it has a structure including two flow path sections F (F3 and F4) in addition to flow path section F1 and flow path section F2. In this case, in the sheet-like structure 18 shown in Fig. 14, the four flow path sections F are connected to the detection section E so as to face each other.

[0061] In the sheet-like structures shown in Figures 11 to 14, the number of flow path sections F is preferably four or less, more preferably three or less, and even more preferably two, from the viewpoint of suppressing an increase in the amount of liquid. Furthermore, the number of connection points of the flow path sections F to the detection section E is preferably four or less, more preferably three or less, and even more preferably two. It is preferable that at least two of the multiple flow path sections F are connected to the detection section E so as to face each other. It is also preferable that at least two of the multiple flow path sections F have approximately the same shape.

[0062] The sheet-like structure can be manufactured, for example, by forming flow paths and non-flow paths corresponding to the front surface in a sheet-like material corresponding to the front surface to manufacture a first porous structure layer, and forming flow paths and non-flow paths corresponding to the back surface in a sheet-like material corresponding to the back surface to manufacture a second porous structure layer, and then laminating these layers together. Alternatively, the sheet-like structure can be manufactured by forming flow paths and non-flow paths corresponding to the front surface in a portion of a single sheet-like material to manufacture a first porous structure layer, and forming flow paths and non-flow paths corresponding to the back surface in another portion of the single sheet-like material to manufacture a second porous structure layer, and then folding the single sheet-like material while adjusting the positions of the first porous structure layer and the second porous structure layer.

[0063] The sheet-like structure of the present invention is preferably produced by forming a first porous structure layer on one surface (front side) of a single sheet-like material and a second porous structure layer on the other surface (back side). Such a sheet-like structure, in which a first porous structure layer and a second porous structure layer are formed on both surfaces of a single sheet-like material, respectively, has various advantages, such as (1) avoiding the labor and cost of stacking (or folding), (2) ensuring fluid flow between the first porous structure layer and the second porous structure layer by capillary action, and (3) eliminating the need for a jig or the like for maintaining the stacked (or folded) sheet-like material, and therefore facilitating disposal.

[0064] Specific methods for producing sheet-like structures include, for example, the following. [Method for producing sheet-like structures] First, a hydrophobic material, a colorant, and a resin are blended and melt-mixed, for example, at 100°C or higher and 140°C or lower, to prepare a wax ink. The resulting wax ink is applied to a substrate such as a polyethylene terephthalate film to produce an ink ribbon. Next, a specific flow path pattern is printed on high-quality paper using a thermal transfer printer (for example, device name: Resprit R412v-ex, manufactured by Sato Holdings Corporation), thereby forming a non-flow path pattern in which the flow path pattern is omitted from the printed portion of the ink ribbon. The ink ribbon with the non-flow path pattern formed is fixed to the front and back of filter paper, and then passed through a laminator (for example, device name: GL535ML, manufactured by GBG) set at a predetermined temperature and line speed, whereby the wax ink is transferred and penetrated into the filter paper to form three-dimensional flow paths, thereby producing a sheet-like structure. The filter paper is not particularly limited and can be appropriately selected depending on the purpose. For example, the filter paper may have an average thickness of 220 μm and a basis weight of 85 g / m ３ A filter paper having a capillary flow time (CFT) of 95.1 seconds / 4 cm can be used. Here, the "predetermined temperature and line speed" are not particularly limited as long as the conditions are such that the wax ink can penetrate and be transferred to the filter paper, but for transfer, a line speed of 10 mm / second at 85°C can be used, and for penetration, a line speed of 5 mm / second at 85°C can be used.

[0065] A blocking agent may be applied in advance to the fluid receiving unit A and the detection unit E in order to prevent fluids (such as specimens such as antigens and reagents such as antibodies) from flowing through and being adsorbed thereto. Examples of the blocking agent include an aqueous albumin solution, but it is preferable to select an appropriate agent depending on the type of fluid and its physical properties such as viscosity.

[0066] (Test Device) The sheet-like structure of the present invention can be suitably used as a test device, such as a pregnancy test kit or a test device that uses a measurement method called immunochromatography, which combines the principles of sandwich ELISA and chromatography.

[0067] Next, the present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0068] <Preparation of Ink Ribbon> A wax ink was prepared by blending the following materials and melt-mixing them at 100°C. Paraffin wax (product name: ParaffinWax-135, manufactured by Nippon Seiro Co., Ltd.) as a hydrophobic material: 72.0 parts by mass Synthetic wax (product name: Diacarna (registered trademark) 30, manufactured by Mitsubishi Chemical Corporation) as a hydrophobic material: 18.0 parts by mass Carbon black (product name: MA-100, manufactured by Mitsubishi Chemical Corporation) as a colorant: 1.8 parts by mass Resin (product name: Ultrathene (registered trademark) 722, manufactured by Tosoh Corporation) 11.25 parts by mass The viscosity of the obtained wax ink was 140°C and a shear rate of 3000 s －１ The viscosity was measured using a rheometer AR-G2 (manufactured by TA Instruments Co., Ltd.).

[0069] The obtained wax ink was applied to a polyethylene terephthalate film (trade name: Lumirror (registered trademark) #6C F531, manufactured by Toray Industries, Inc.) having an average thickness of 6 μm as a substrate to an average thickness of 10 μm, thereby producing an ink ribbon.

[0070] <Formation of non-flow path pattern 1> Using a thermal transfer printer (device name: Resprit R412v-ex, manufactured by Sato Holdings Corporation) and an ink ribbon, flow path pattern 1 (a set of a flow path pattern for the front surface and a flow path pattern for the back surface) shown in FIG. 15 was printed on high-quality paper, thereby forming non-flow path pattern 1 (a set of a non-flow path pattern for the front surface and a non-flow path pattern for the back surface) in which flow path pattern 1 was omitted from the printed portion of the ink ribbon (see FIG. 16).

[0071] <Formation of non-flow path pattern 2> Using a thermal transfer printer (device name: Resprit R412v-ex, manufactured by Sato Holdings Corporation) and an ink ribbon, flow path pattern 2 (a set of a flow path pattern for the front surface and a flow path pattern for the back surface) shown in FIG. 17 was printed on high-quality paper, thereby forming non-flow path pattern 2 (a set of a non-flow path pattern for the front surface and a non-flow path pattern for the back surface) in which flow path pattern 1 was omitted from the printed portion of the ink ribbon (see FIG. 18).

[0072] Example 1 Formation of Flow Channels Using a laminator (device name: GL535ML, manufactured by GBC), ink ribbons having a non-flow channel pattern 1 shown in FIG. 16 were fixed to the front and back surfaces of filter paper (product name: Whatman (registered trademark) quantitative filter paper #41, manufactured by Global Life Science Technologies Japan, Inc.) as a material M having a porous structure, and wax ink was printed on the ink ribbons. The filter paper was passed through a laminator set to a predetermined temperature, and the following lamination conditions (1) to (3) were sequentially carried out, whereby wax ink having a predetermined shape was allowed to penetrate into the filter paper from the front and back surfaces of the filter paper, forming three-dimensional flow channels in the filter paper, and an intermediate sheet-like structure was produced.

[0073] -Lamination conditions- (1) Lamination was performed at a set temperature of 85°C and a line speed of 10 mm / sec to transfer the ink to the filter paper. (2) Next, lamination was performed at a set temperature of 85°C and a line speed of 5 mm / sec to allow the ink to penetrate into the filter paper. (3) Further, lamination was performed at a set temperature of 85°C and a line speed of 5 mm / sec to allow the ink to penetrate into the filter paper.

[0074] (Example 1) <Formation of Support Layer> An adhesive tape (product name: 660PF, manufactured by Nichiban Co., Ltd.) was superposed as a support layer so as to cover the back surface of the detection section of the obtained sheet-like structure intermediate, and laminated using a hand roller at room temperature. A sheet-like structure of Example 1 was produced in which a support layer was formed on the back surface of the detection section.

[0075] The sheet-like structure of Example 1 corresponds to the sheet-like structure of the first embodiment shown in Figures 1 to 3. As shown in Figures 1 to 3, the sheet-like structure 11 of Example 1 has a porous structure layer 101 having a flow path X with a porous structure that allows fluid to flow through it and a non-flow path Y that does not allow fluid to flow through it. The flow path X has a fluid receiving section A, flow path sections B, C, and D, and a detection section E. The fluid receiving section A, flow path sections B, C, and D, and detection section E are connected in this order to allow the fluid to flow through them. The fluid receiving section A and flow path sections B, C, and D are connected to the front and back surfaces of the porous structure layer 101. The sheet-like structure 11 further has a support layer 301 that covers the back surface of the detection section E, and the porous structure layer on the back surface of the detection section E is not exposed. A configuration overview of the sheet-like structure is shown in Table 1.

[0076] <Evaluation> Evaluation of capillary flow time and evaluation of color unevenness at the detection area were carried out according to the following procedures. The evaluation results are shown in Table 2.

[0077] <<Capillary flow time evaluation>> Capillary flow time (CFT) refers to the time it takes for 4 cm of pure water to be absorbed when one end of a test sample such as filter paper is placed in pure water. The capillary flow time (CFT) of the flow channel was measured by the following procedure. ｆ ), the capillary flow time (CFT) of the detection section ｄ ), CFT ｆ CFT for ｄ The ratio of (CFT ｄ / CFT ｆ ) was evaluated.

[0078] (1) As specimens, strip-shaped test sheet structures measuring 1 cm x 6 cm were prepared for each of the flow path section and the detection section. Here, the test sheet structure for the flow path section of the sheet structure of Example 1 was filter paper itself, and the test sheet structure for the detection section of the sheet structure of Example 1 was filter paper with a support layer laminated on the back surface. (2) The end of the test sheet structure was immersed vertically in pure water, and the time required for 4 cm of pure water to be absorbed was measured using a stopwatch. (3) Measurements were made with n = 6 and the average value was calculated, and the obtained average value was used as the capillary flow time (CFT) of the flow path section. ｆ), and the capillary flow time (CFT) of the detection section ｄ ) respectively. ｆ CFT for ｄ The ratio of (CFT ｄ / CFT ｆ ) was calculated.

[0079] In Examples 2 to 4, when the detection unit had a backside barrier, wax ink was transferred and impregnated onto the backside of the filter paper, and a test sheet-like structure for the detection unit was prepared in which a hydrophobic material was impregnated onto the backside of the detection unit to form a non-flow path portion, and evaluation was similarly performed using this structure according to the procedures (1) to (3) above.

[0080] <<Evaluation of Color Unevenness in the Detection Section>> Evaluation of color unevenness in the detection section was performed using the following procedure. (1) Using a micropipette, 1 μL of aqueous fluorescent ink (Fluorescent Coat 96 Sky Blue, manufactured by Tombow Pencil Co., Ltd.) was dripped into the flow path section C. (2) Next, 12 μL of distilled water was dripped into the fluid receiving section A. (3) By capillary action, the distilled water moved to the fluid receiving section A, flow path sections B, C, and D, and the detection section E, and the aqueous fluorescent ink moved to the detection section E along with the distilled water. (4) 10 minutes after the distilled water was added, the surface of the detection section E was photographed with a scanner. (5) Using image processing software ImageJ (https: / / imagej.net / ij / ), the cyan color intensity was quantified from the cyan color information on the entire surface of the detection section E as the target region, and the average value of the cyan color intensity for the evaluation number n = 12 was expressed as the "color intensity." (6) For each target area, the coefficient of variation (%) was calculated from the average value and standard deviation of the cyan color distribution. The average value of the coefficient of variation for the evaluation number n = 12 was shown as "color unevenness." The smaller the "color unevenness" value, the less color unevenness there was.

[0081] (Comparative Example 1) A sheet-like structure of Comparative Example 1 was produced and evaluated in the same manner as in Example 1, except that a support layer was not formed and an intermediate sheet-like structure was used as the sheet-like structure of Comparative Example 1. A schematic plan view of the production process of the sheet-like structure of Comparative Example 1 is shown in Figure 19. The configuration of the sheet-like structure and the evaluation results are shown in Tables 1 and 2.

[0082] Example 2 A sheet-like structure of Example 2 was manufactured and evaluated in the same manner as in Example 1, except that a non-channel pattern 2 shown in FIG. 18 was used to form a channel instead of non-channel pattern 1 in Example 1, thereby providing a non-channel on the back side of the detection unit, and no support layer was formed; and further, the average thickness of the wax ink for the back side in non-channel pattern 2 was changed from 10 μm to 6 μm to form a channel, thereby reducing the thickness of the non-channel on the back side of the detection unit and setting the ratio (t2 / t1) to 6 / 10. The configuration of the sheet-like structure and the evaluation results are shown in Tables 1 and 2. The sheet-like structure of Example 2 corresponds to the sheet-like structure of the third embodiment shown in FIGS. 7 and 4 and 5.

[0083] Example 3 A sheet-like structure of Example 3 was manufactured and evaluated in the same manner as in Example 2, except that in Example 2, the average thickness of the wax ink for the back surface in the non-flow path pattern 2 was changed from 6 μm to 10 μm to form a flow path, thereby increasing the thickness of the non-flow path on the back surface side of the detection unit and setting the ratio (t2 / t1) to 1 / 1. The configuration of the sheet-like structure and the evaluation results are shown in Tables 1 and 2. The sheet-like structure of Example 3 corresponds to the sheet-like structure of the second embodiment shown in Figures 4 to 6.

[0084] Example 4 A sheet-like structure of Example 4 was produced and evaluated in the same manner as in Example 3, except that a support layer was formed on the entire back surface of the sheet-like structure by the following procedure. The configuration of the sheet-like structure and the evaluation results are shown in Tables 1 and 2. The sheet-like structure of Example 4 corresponds to the sheet-like structure of the fourth embodiment shown in Figures 8 to 10.

[0085] <Formation of Support Layer> An adhesive tape (product name: 660PF, manufactured by Nichiban Co., Ltd.) was superposed as a support layer so as to cover the entire back surface of the sheet-like structure of Example 3, and laminated using a hand roller at room temperature to produce a sheet-like structure of Example 4 in which a support layer was formed on the entire back surface.

[0086]

[0087]

[0088] As is clear from Table 2, the capillary flow time (CFT) of the flow channel portion in the sheet-like structure of Example 1 was ｆ The capillary flow time (CFT) of the detection section is 95.1 seconds / 4 cm, and the flow rate of the fluid is fast at 120 seconds / 4 cm or less, so the reaction speed is maintained. ｄ ) is 116.5 [sec / 4cm], 300 sec / 4cm or less, and CFT ｆ <CFT ｄ It was. ｆ CFT for ｄ The ratio of (CFT ｄ / CFT ｆ ) was 1.2, which satisfied the preferable range of 1.2 or more and 2.9 or less, and the color unevenness was 16.0% (16.0% or less). ｄ / CFT ｆ It was found that the coloring was more uniform than in Comparative Example 1 in which the ratio of the coloring rate to the total coloring rate was 1, and the quantitative accuracy was improved.

[0089] In Examples 2 and 3, a non-flow channel is provided on the back side of the detection unit, thereby reducing the capillary flow time (CFT) of the detection unit. ｄ ) slows down, and the ratio (CFT ｄ / CFT ｆ ) increased, and the color unevenness was further reduced. Therefore, it was found that the color was made more uniform and the quantitative accuracy was improved while maintaining the rapidity of the reaction.

[0090] In Example 4, a support layer is provided on the entire back surface of the porous structure layer, thereby reducing the capillary flow time (CFT) of the flow channel. ｆ Although the reaction time was slower, the flow rate of the fluid was fast at 120 [sec / 4 cm] or less, and the rapidity of the reaction was maintained.

[0091] This international application claims priority based on Japanese Patent Application No. 2023-217596, filed on December 25, 2023, the entire contents of which are incorporated herein by reference.

[0092] DESCRIPTION OF SYMBOLS 11 Sheet-like structure of first embodiment 12 Sheet-like structure of second embodiment 13 Sheet-like structure of third embodiment 14 Sheet-like structure of fourth embodiment 15 Sheet-like structure of fifth embodiment 16 Sheet-like structure of sixth embodiment 17 Sheet-like structure of seventh embodiment 18 Sheet-like structure of eighth embodiment 11A Sheet-like structure (Comparative Example 1) 101 Porous structure layer 102 Porous structure layer 103 Porous structure layer 104 Porous structure layer 301 Support layer 304 Support layer 306 Support layer A Fluid receiving section (flow path) B Flow path section (flow path) C Flow path section (flow path) D Flow path section (flow path) E Detection section (flow path) X Flow path Y Non-flow path m Hydrophobic material M Material M' Material

Claims

1. A porous structure layer having a flow path with a porous structure through which a fluid can flow and a non-flow path through which the fluid does not flow, the flow path having a fluid receiving portion, a flow path portion, and a detection portion, the fluid receiving portion, the flow path portion, and the detection portion being connected in this order to allow the fluid to flow, and the capillary flow time CFT of the flow path portion ｆ with respect to the capillary flow time CFT of the detection portion ｄ and the ratio (CFT ｄ / CFT ｆ ) is 1.2 or more. A sheet-like structure characterized by this.

2. The capillary flow time CFT of the flow path portion ｆ The ratio of the capillary flow time CFT of the detection portion ｄ to that (CFT ｄ / CFT ｆ ) is 1.2 or more and 2.9 or less. The sheet-like structure according to claim 1 3. The capillary flow time CFT of the flow path portion ｆ The sheet-like structure according to any one of claims 1 to 3, wherein the capillary flow time CFT is 120 seconds / 4 cm or less.

4. Capillary flow time CFT of the detection unit ｄ The sheet-like structure according to any one of claims 1 to 4, wherein the capillary flow time CFT is 300 seconds / 4 cm or less.

5. The sheet-like structure according to any one of claims 1 to 5, wherein the non-channel is impregnated with a hydrophobic material in the porous structure.

6. The sheet-like structure according to any one of claims 1 to 6, wherein the channel has the fluid receiving portion and the channel portion communicating with the first surface and the second surface of the porous structure layer, and the detection portion communicating with the first surface and not exposed on the second surface.

7. The sheet-like structure according to claim 6, wherein a support layer is provided on the second surface of the detection portion, or the porous structure on the second surface of the detection portion is impregnated with a hydrophobic material.

8. The sheet-like structure according to claim 3 or 6, further having a support layer on the second surface of the fluid receiving portion and the channel portion.

9. The sheet-like structure according to claim 8, wherein the support layer is water-impermeable.

10. The sheet-like structure according to any one of claims 1 to 9, which is an inspection device.

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