TW202109044A - Absorptive pad for immunochromatographic diagnosis kit and immunochromatographic diagnosis kit - Google Patents

Abstract

Provided is an absorptive pad for an immunochromatographic diagnosis kit. The absorptive pad demonstrates excellent reproducibility of test results and is configured not to cause a backward flow. The present invention relates to an absorptive pad for an immunochromatographic diagnosis kit. The absorptive pad includes carboxymethylated cellulose fibers and is characterized in that the average degree of substitution of hydroxyl group in a glucose unit constituting the carboxymethylated cellulose fibers is 0.05-1.5.

Description

Absorbent pad for immunochromatographic diagnostic kit and immunochromatographic diagnostic kit

The invention relates to an absorbent pad for an immunochromatographic diagnosis kit. In more detail, the present invention relates to an absorbent pad for an immunochromatographic diagnostic kit that has excellent reproducibility of test results and does not cause backflow.

In recent years, various simple inspection reagents or diagnostic reagents and diagnostic kits have been developed for various inspections in a short period of time for the presence of pathogen infections such as viruses or bacteria, pregnancy, cancer markers, specific raw materials in foods or residual pesticides and other hazardous substances. group. These are specific reactions performed by each test target substance and a substance that specifically reacts with the test target substance. In particular, with regard to immunological assays using antigen-antibody reactions between antigens and antibodies, immunochromatographic assays, turbidimetric immunoassays, enzyme immunoassays, chemiluminescence assays, radioimmunoassays, and surface electroporation have been developed. The measurement method of plasma resonance and many other measurement methods. And these measurement methods are used for inspections of diseases in hospitals, clinics, etc., or food inspections of food companies, etc. Among them, the immunochromatographic assay does not require special equipment, machinery, or knowledge, is easy to operate, low in price, and can be quickly diagnosed, and so many tests have been performed. In recent years, pregnancy test reagents or HIV (human immunodeficiency virus, human immunodeficiency virus) test reagents have been sold at ordinary pharmacies, and even ordinary consumers can perform the test. Furthermore, it is not only possible to perform qualitative tests for the presence or absence of test substances. , It can also carry out quantitative inspection of measured quantity.

As the measurement principle of the immunochromatographic assay, there is a method called a sandwich method or a method called a competition method. In addition, as a measurement method, there is a method called a percolation type or a lateral flow type. As the test target substance in the specimen, various substances can be detected, but as a typical example, there is a sandwich method to detect antigens, and the following operations are performed in order. (1) The antibody that specifically binds to the antigen of the test target substance is immobilized on a specific part of the chromatographic medium such as the membrane of the chromatographic medium, and a test line (hereinafter referred to as "TL") is formed at any position of the chromatographic medium. ") of the reaction site. (2) Prepare detection reagents made by loading labeling substances such as enzymes, labeling substances, fluorescent labeling substances, and magnetic particles with antibodies that specifically bind to the substance to be inspected, and apply the detection reagents to binding pads, etc., and then dry them to form The detection reagent containing part is combined with the above-mentioned chromatographic medium to form an immunochromatographic diagnosis kit. (3) Drop the sample containing the antigen itself or a solution diluted with any liquid to a specific position of the above immunochromatographic diagnostic kit, such as a sample pad, so that the antigen and the detection reagent are on the chromatography medium Unfold. Through these operations, in the reaction site, the antibody immobilized on the chromatographic medium captures the labeling substance through the antigen, and detects the signal of the labeling substance, thereby performing the diagnosis using the immunochromatographic diagnosis kit.

Since the previous, the use of the above-mentioned immunochromatographic examination has been particularly strongly required in the clinical scene to accurately determine the disease. For example, there are several examination items useful for the diagnosis of acute coronary syndrome. In acute coronary syndromes, acute myocardial infarction is a disease in which the coronary arteries are blocked by thrombus and myocardial tissue is trapped in necrosis. The success of reperfusion in the early stage of onset will have a great impact on the prognosis. Therefore, a highly accurate diagnosis is more important. In this case, the markers required for diagnosis must be quantitatively detected. Of course, the immunochromatographic diagnostic kit used in the diagnosis must have an infinitely small deviation in the color intensity between the products of the immunochromatographic diagnostic kit. Assuming the use of immunochromatographic diagnostic kits with large deviations in color rendering intensity, of course it will lead to misdiagnosis. In the case of the above diseases, there is even the possibility of life-threatening due to misdiagnosis. It can be seen from these that the infinite reduction of the deviation between the products of the immunochromatographic diagnostic kit is one of the larger issues in the development of the immunochromatographic diagnostic kit.

The reason for the deviation is considered to be the influence of the components that make up the set, but especially for the absorbent pad, since it is the part responsible for absorbing liquid, it leads to deviations in the color intensity due to abnormalities such as background coloring. Here, "background" refers to the phenomenon caused by the coloring of the chromatographic medium membrane due to clogging of the labeling reagent or non-specific adsorption on the pores of the chromatographic medium membrane. If the background is poor, the contrast between the chromatographic medium film and the test line (TL) becomes poor, and it is difficult to observe the color line of the TL, and it is difficult to determine it in the medical field. Furthermore, if the background is poor, the judgment of negative TL (that is, no color development) becomes difficult. Such phenomena may cause misdiagnosis.

In addition, as one of the causes of misdiagnosis in addition to the background coloring, there are cases where the background coloring is caused by the backflow of the labeling reagent after the determination. Usually the determination time of immunochromatographic diagnostic kits is determined by each immunochromatographic diagnostic kit, but in extremely busy clinical scenes, it is often impossible to make a determination within the determination time. Here, "counter-flow of labeling reagent" means that the drying of the chromatographic medium causes the labeling reagent that is temporarily absorbed by the absorbent pad to flow backward and spread in the opposite direction on the chromatographic medium. This backflow causes background coloration, or further contaminates the TL, which may cause misdiagnosis.

As the absorbent pad used in the test kit of immunochromatography, cotton, non-woven fabric, filter paper, etc. containing fibers such as cellulose fiber, glass fiber, and pulp were previously used. However, the absorbent pad made of only these materials is affected by its structure, constituent materials, and manufacturing method, and its water absorption is not sufficient, resulting in a deviation in the absorption amount or causing a problem of backflow. In order to solve these problems, the following Patent Document 1 studies the use of absorbent pads using superabsorbent polymer particles. In addition, the following Patent Document 2 studies the use of spraying silica particles to non-woven materials such as cellulose fibers. Chengzhi absorbent pad. However, in the case of these absorbent pads, it is difficult to homogenize the fiber density or the uniformity of the spray amount. Even if the water absorption is improved, the water absorption speed between products is likely to vary. Therefore, the current situation is that there is no variation between products. Improved.

In addition, it is also reported that there are problems in the manufacturing steps of the kit caused by the previous absorbent pad. For example, absorbent pads made of long glass fibers are used in the production of immunochromatographic diagnostic kits, where the fibers that fall off during cutting are flying in the form of dust. If the dust of the long glass fiber is inhaled, it may cause bronchial inflammation. Therefore, from the viewpoint of endangering the health of manufacturing workers, it is not suitable for use. Furthermore, there are many reports of abnormalities such as blade defects in the cutting module. For these reasons, it is desirable to avoid the use of long glass fiber absorbent pads as much as possible. As mentioned above, there is a strong demand for an absorbent pad that minimizes deviation and does not cause backflow. [Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent No. 6134615 [Patent Document 2] Japanese Patent Laid-Open No. 2012-189346

[The problem to be solved by the invention]

In view of the above-mentioned level of the prior art, the problem to be solved by the present invention is to provide an absorbent pad for an immunochromatographic diagnostic kit that has excellent reproducibility of test results and does not cause backflow. [Technical means to solve the problem]

In order to solve the above-mentioned problems, the inventors have conducted intensive research and repeated experiments. As a result, they unexpectedly discovered that the reproducibility is improved by the absorbent pad containing specific carboxymethylated cellulose fibers, thereby suppressing backflow, thereby completing this invention.

That is, the present invention is as follows. [1] An absorbent pad for an immunochromatographic diagnostic kit, characterized in that it contains carboxymethylated cellulose fibers and constitutes the hydroxyl group in the glucose unit of the carboxymethylated cellulose fibers The average degree of substitution is above 0.05 and below 1.5. [2] The absorbent pad for an immunochromatographic diagnostic kit as described in [1] above, wherein the capture and release index of the pad is 0.5 or less. [3] The absorbent pad for an immunochromatographic diagnostic kit as described in [1] or [2] above, wherein the weight per unit area of the pad is 10 g/m ² or more and 400 g/m ² or less, and the thickness is 0.03 mm above 10.00 mm. [4] The absorbent pad for an immunochromatographic diagnostic kit as described in any one of [1] to [3] above, wherein the absorption amount of the pad when immersed in physiological saline is 5 g/100 cm ² or more 50 g/100 cm ² or less. [5] The absorbent pad for an immunochromatographic diagnostic kit as described in any one of [1] to [4] above, wherein the pad is in the form of a single-layer sheet or a laminated sheet. [6] An immunochromatographic diagnostic kit comprising the absorbent pad for the immunochromatographic diagnostic kit as described in any one of [1] to [5] above. [Effects of Invention]

The immunochromatographic diagnostic kit using the absorbent pad for the immunochromatographic diagnostic kit of the present invention has excellent reproducibility of inspection results and does not cause backflow.

Hereinafter, embodiments of the present invention will be described in detail. The absorbent pad for the immunochromatographic diagnostic kit of this embodiment is characterized in that it contains carboxymethylated cellulose fibers, and constitutes the hydroxyl group in the glucose unit of the carboxymethylated cellulose fibers The average degree of substitution is 0.05 or more and 1.5 or less.

Inspection methods using immunochromatography performed using the immunochromatography diagnostic kit usually include a percolation method in which a solution containing a analyte passes through the membrane in a vertical direction, and a lateral flow method in which it passes in a horizontal direction. Two types, the absorbent pad for the immunochromatographic diagnostic kit of this embodiment can be used in any of these methods, and the meaning of the system of the immunochromatographic diagnostic kit for water absorption is not limited to these.

The carboxymethylated cellulose fiber contained in the absorbent pad for the immunochromatographic diagnostic kit of this embodiment has an average degree of substitution of the hydroxyl group in the glucose unit of the cellulose constituting the carboxymethylated cellulose is 0.05 or more and 1.5 or less. If the average substitution is too high, a water barrier will be formed in the front part of the absorbent pad when absorbing the expanded liquid. As a result, it is impossible to absorb a sufficient amount of developing solution, which will cause poor deployment, which may result in inspection deviations. The upper limit of the average degree of substitution is preferably 1.3 or less, more preferably 0.9 or less. More preferably, it is 0.6 or less. If the average degree of substitution is above 0.05, sufficient liquid absorption can be ensured. The lower limit of the average degree of substitution is preferably 0.1 or more, more preferably 0.2 or more.

In addition, in the above-mentioned carboxymethylated cellulose fiber, at the time of carboxymethylation, the terminal of the carboxymethyl group becomes a sodium salt, and thereafter, a part of the carboxymethyl group can be treated with an acid to make a part of the carboxymethyl group into a proton type. The method of partially protonating the carboxymethylated cellulose fiber is not particularly limited, but it is preferably immersed in acetic acid, hydrochloric acid, and nitric acid adjusted to a specific concentration using an alcohol-containing solvent, and more preferably Protonation is performed by immersing in acetic acid adjusted to a specific concentration using an alcohol-containing solvent.

The absorbent pad for the immunochromatographic diagnostic kit containing carboxymethylated cellulose fibers of this embodiment preferably has a capture and release index of 0.5 or less. In this manual, the "capture and release index" is an index that indicates the balance between the characteristics of the absorbent pad to absorb the liquid imparted and the characteristics of the absorbent pad to maintain the imparted liquid, according to the following formula: Capture and release index = (100×C÷D )÷T {where, C: liquid absorption (g/100 cm ² ), D: weight per unit area (g/m ² ), T: release time (minutes)}. If the capture and release index is too large, the labeled reagent temporarily absorbed by the absorbent pad will flow backward on the chromatographic medium, or inspection deviation may occur. The upper limit of the capture and release index is more preferably 0.3 or less, and still more preferably 0.1 or less. The lower limit is preferably 0.0001 or more, more preferably 0.001 or more. The capture and release index can be controlled by controlling the average degree of substitution, average fiber diameter, fiber length, etc. of the above-mentioned carboxymethylated cellulose fibers and/or the shape of the absorbent pad containing the above-mentioned carboxymethylated cellulose fibers, etc. Make adjustments.

In addition, in this specification, "release time" means that an absorbent pad with a width of 4 mm × a length of 25 mm is placed on a chromatographic medium with a width of 4 mm × a length of 25 mm in an aligned manner, and the entire pad is statically placed on the absorbent pad. When 20 μL of physiological saline is added intravenously, the time required for the physiological saline to begin to transfer from the absorption pad to the chromatography medium is expressed in minutes. Furthermore, as for the measurement of "release time", as long as the relationship between the size of the absorbent pad and the volume of physiological saline is equivalent to the above method, the size of the absorbent pad and the volume of physiological saline that are different from the above method can also be used. .

The average fiber diameter of the carboxymethylated cellulose fiber is preferably 1 μm or more and 100 μm or less. If the average fiber diameter is too large, a water barrier will be formed in the front part of the absorbent pad when absorbing the expanded liquid. As a result, a sufficient amount of developing fluid cannot be absorbed, which leads to poor deployment, resulting in inspection deviations. The upper limit of the fiber diameter is preferably 80 μm or less, more preferably 70 μm or less. If the average fiber diameter is 1 μm or more, sufficient liquid absorption can be ensured. The lower limit of the average fiber diameter is preferably 3 μm or more, more preferably 5 μm or more. Furthermore, regarding the average fiber diameter, the average fiber diameter measured at N=10 using a scanning electron microscope (SEM, manufactured by JEOL) was used as the average fiber diameter.

The form of the absorbent pad for the immunochromatographic diagnostic reagent kit containing carboxymethylated cellulose fibers of this embodiment can be in the form of woven fabric, knitted fabric or non-woven fabric, for example, in the form of non-woven fabric In this case, the weight per unit area (g/m ² ) (ie, non-woven fabric weight (g)/non-woven fabric area (m ² )) is preferably 10 g/m ² or more and 400 g/m ² or less. If the weight per unit area is too low, the absorbent pad used as an immunochromatographic diagnostic reagent cannot obtain a sufficient amount of liquid absorption. The lower limit of the weight per unit area is more preferably 20 g/m ² or more, and still more preferably 30 g/m ² or more. On the other hand, if the weight per unit area is too high, the flexibility will be impaired, which will obviously affect the operation when manufacturing the immunochromatographic diagnostic kit, resulting in deviations in the diagnostic results. The upper limit of the weight per unit area is more preferably 350 g/m ² or less, still more preferably 300 g/m ² or less, still more preferably 250 g/m ² or less, still more preferably 200 g/m ² or less, and still more It is preferably 190 g/m ² or less, and more preferably 180 g/m ² or less.

The thickness of the absorbent pad for the immunochromatographic diagnostic kit containing carboxymethylated cellulose fibers of this embodiment, for example, when the absorbent pad is in the shape of a woven fabric or a sheet, is preferably 0.03 mm or more and 10.00 mm or less . If the thickness of the pad is too thick, for example, when it is used in an immunochromatographic diagnosis kit, it is difficult to store it in the outer shell, and as a result, the deviation of the diagnosis result will increase. The upper limit of the thickness of the pad is more preferably 9.00 mm or less, and still more preferably 8.00 mm or less. On the other hand, if the sheet is too thin, the absorbent pad used as an immunochromatographic diagnostic kit cannot ensure sufficient liquid absorption. The lower limit of the thickness of the pad is more preferably 0.05 mm or more, and still more preferably 0.10 mm or more. In this manual, the "thickness" of the pad refers to the value measured by the thickness test according to JIS-L1096 and the load is set to 1.96 kPa.

The absorbent pad for the immunochromatographic diagnostic kit of this embodiment preferably has a liquid absorption amount of 5 g/100 cm ² or more and 50 g/100 cm ² or less when immersed in physiological saline. If the suction volume is too large, when used in the immunochromatographic diagnostic kit, the structure will collapse after suction, causing poor deployment. The upper limit of the liquid absorption is preferably 50 g/100 cm ² or less, more preferably 30 g/100 cm ² or less. If the liquid absorption volume is less than 5 g/100 cm ² , the desired effect may not be exerted, which may cause backflow. The lower limit of the liquid absorption is preferably 5 g/100 cm ² or more, more preferably 10 g/100 cm ² or more.

The cellulose fiber (before carboxymethylation) used as the raw material of the above-mentioned carboxymethylated cellulose fiber is not particularly limited, and examples include cupramine rayon, mucous rayon, lyocell, Well-known cellulosic fibers such as cotton, pulp, multi-brain fibers, etc., preferably include cupramine and mucous rayon, more preferably cupramine rayon. Cellulosic fiber materials have a lower degree of polymerization. In this material, if the degree of substitution is increased, the fiber is easy to decompose, and the degree of substitution must be controlled as low as possible. In contrast, if cupra rayon is used, it will polymerize. It has the advantage that it is not easy to collapse even if it is a relatively high degree of substitution, and a wide range of substitution degrees can be selected.

The cellulose fibers may be either long fibers or short fibers. The long fiber is preferably a continuous long fiber. In this specification, long fibers refer to those having a fiber length of 10 mm or more, and the fiber length is preferably 20 mm or more, more preferably 50 mm or more, and more preferably continuous long fibers. Short-fiber cellulose sheets are short fibers. Therefore, if the degree of substitution is increased, the fibers are easy to separate. It must be controlled to a low degree of substitution as much as possible. On the other hand, if continuous long-fiber sheets are used, there may be relatively high The degree of substitution has the advantage that it is not easy to collapse, and a wide range of degrees of substitution can be selected.

As the form of the absorbent pad for the immunochromatographic diagnostic kit containing carboxymethylated cellulose fibers of this embodiment, the form of cotton, woven fabric, knitted fabric or non-woven fabric is preferred, and more preferably The form of the woven fabric or non-woven fabric of the carboxymethylated regenerated cellulose fiber is more preferably the form of the non-woven fabric of the carboxymethylated regenerated cellulose fiber. If it is in the form of a non-woven fabric, the fibers will also be intertwined in a gelled state when wet, so higher liquid absorption can be obtained while maintaining the strength when wet, and it can be used for immunochromatography well. Absorbent pad for diagnostic kit.

The absorbent pad for the immunochromatographic diagnostic kit containing carboxymethylated cellulose fibers of this embodiment may also include fibers other than natural or regenerated cellulose fibers within the range that does not impair the desired effect. , For example: synthetic fibers such as polyester fibers, polypropylene fibers, nylon fibers, or bioabsorbable fibers such as polyglycolic acid, polylactic acid, and polymalic acid. As a range that does not impair the desired effect, such a material is preferably 50% or less, and more preferably 30% or less. Such fibers may be long fibers or short fibers. As long fibers, continuous long fibers are preferred.

The absorbent pad for the immunochromatographic diagnostic kit of this embodiment may be further laminated with sheets depending on various applications. In the case of laminated non-woven fabrics, hot-melting methods such as hot embossing, ultrasonic fusion, mechanical interlacing methods such as needle punching and water spraying, hot-melt adhesives, urethane-based adhesives, and other adhesives can be used. Various well-known methods represented by methods, extrusion lamination, etc., are not particularly limited.

The sheet material used in the laminated layer of the sheet is not limited in any way, and can be cellulose, thermoplastic resin, or bioabsorbable polymers such as polyglycolic acid, polylactic acid, and polymalic acid. Among them, the thermoplastic resin may be polyolefin resin, polyester resin, polyamide resin, and specific examples include ethylene, propylene, 1-butene, 1-hexene, and 4-methyl-1 -Pentene, 1-octene and other α-olefin homopolymers or copolymers, namely high-pressure low-density polyethylene, linear low-density polyethylene (LLDPE), high-density polyethylene, polypropylene (propylene homopolymer) , Polypropylene random copolymer, poly-1-butene, poly-4-methyl-1-pentene, ethylene-propylene random copolymer, ethylene-1-butene random copolymer, propylene-1-butene Random copolymers and other polyolefins, polyesters (polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, etc.), polyamides (nylon-6, nylon-66, etc.) , Poly(hexamethylene adipamide, metaxylylenediamine, etc.), polyvinyl chloride, polyimide, ethylene-vinyl acetate copolymer, polyacrylonitrile, polycarbonate, polystyrene, ionic polymer, mixtures of these Wait. Particularly when used in the case of this embodiment, in terms of stability or versatility with respect to heat or moisture, polyethylene terephthalate, polybutylene terephthalate, and polybutylene terephthalate are preferred in terms of stability or versatility. Any one or mixture of propylene and polyethylene.

Generally, thermoplastic resins are mostly hydrophobic, and even if the structure is formed as a non-woven fabric, there are almost no water absorbers. In this embodiment, it can be seen that the variation in water absorption can be reduced by using a non-woven fabric containing fibers of a hydrophobic thermoplastic resin for hydrophilization treatment. The method of hydrophilization is not particularly limited. If it is a physical processing method, for example, corona treatment or plasma treatment may be used for hydrophilization, and the chemical processing method may include, for example, the introduction of surface functional groups, such as by oxidation treatment. Introduce sulfonic acid groups, carboxylic acid groups, etc.; or use water-soluble polymers such as polyvinyl alcohol (PVA), polyester resins, polystyrene sulfonic acid, or polyglutamine by dipping or spraying An acid and/or surfactant, for example, a treatment agent such as a nonionic surfactant, an anionic surfactant, a cationic surfactant, or an amphoteric surfactant, is impregnated with a treatment agent such as a nonwoven fabric, and is applied to a known method such as a method. Consider the necessary water absorption of the absorbent pad, and select the appropriate hydrophilization processing method and conditions, such as the amount of treatment agent used and the amount of functional group introduced.

When a non-woven fabric is used in the laminate of the sheet, the method of making the non-woven fabric is not particularly limited. Examples include: spunbonded non-woven fabric, melt-blown non-woven fabric, wet non-woven fabric, dry non-woven fabric, dry pulp non-woven fabric, flash spun non-woven fabric, open fiber Non-woven fabrics, etc., particularly as non-woven fabrics containing ultrafine fibers, melt-blown non-woven fabrics or flash-spun non-woven fabrics are preferred.

As a non-woven fabric used in the laminate of sheets, it can be used well with a basis weight of 20 g/m ² or more and 200 g/m ² or less, a thickness of 0.06 mm or more and 1.20 mm or less, and an average fiber diameter of 0.7 μm or more and 5.0 μm The following ones.

The manufacturing method of the absorbent pad for the immunochromatographic diagnostic kit containing the carboxymethylated cellulose fiber of this embodiment is illustrated below, but it is not limited to this method. While maintaining the structure of natural or regenerated cellulose fibers in an alkaline state in an alcohol-containing sodium hydroxide aqueous solution, stir at 35°C for 30 minutes. Thereafter, after draining the reagents in the reaction vessel, add alcohol-containing sodium monochloroacetate, and stir at 30°C to 55°C for 1 to 12 hours. At this time, the degree of substitution is controlled by the bath ratio, temperature, and time of the reaction liquid and the structure. In addition, other reaction conditions may be appropriately changed in consideration of production costs and the like. After adjusting the pH value of the obtained structure to 6.0-8.0 with an ethanol aqueous solution containing acetic acid, alcohol substitution was performed with 70 wt%, 90 wt%, and 100 wt% ethanol. Since it will harden even if the water content is small, by slowly increasing the alcohol concentration, it is possible to reliably perform alcohol substitution and maintain morphological stability. Then it was immersed in an acid-containing ethanol solution adjusted to a specific concentration, stirred for 1 hour, replaced by alcohol with 70 wt%, 90 wt%, and 100 wt% ethanol, and dried to obtain a protonated sheet structure . Then it was immersed in an ethanol aqueous solution containing calcium hydroxide adjusted to a specific concentration, stirred for 1 hour, replaced by alcohol with 70 wt%, 90 wt%, and 100 wt% ethanol, and dried to obtain the sheet form of the embodiment of the present case pad.

The "diagnosis method" implemented using the immunochromatographic diagnostic kit using the absorbent pad for the immunochromatographic diagnostic kit of this embodiment refers to various diagnoses performed in vitro using the immunochromatographic diagnostic kit. The diagnostic target is not particularly limited, and it can be used for inspections of various diagnostic targets such as human, animal, food, plant, and other environmental inspections. In a general diagnostic procedure, a specimen sample is collected from the inspection object, and pre-processed, such as extraction or filtration, if necessary, and then dropped into the sample pad. After the inspection starts, it waits for a certain time, depending on the presence or absence of the inspection object. The color development, judge the diagnosis result. Of course, it is not limited to this procedure, and can also be used for diagnosis with the same procedure and principle. Preferably, excess foreign objects or inclusions can be removed by pre-filtering the specimen sample, so that further rapid diagnosis or improvement of diagnosis accuracy can be expected.

The immunochromatographic diagnosis kit of this embodiment is used to easily detect the presence or absence of test target substances in various specimens. As the types of diagnostic kits, there are lateral flow type or percolation type. It is not particularly limited as long as it uses a labeling reagent or an absorbent pad, and a lateral flow type is preferred. In addition, there are a measuring rod type and a box type in the side flow type, and these types are not particularly limited. The composition of the diagnostic kit is not particularly limited, and it may be any composition as long as it is a composition commonly used in the field. The component is not particularly limited as long as it is a user in the field. Examples include (a) sample pads, (b) binding pads (including antibody sensitization labeling reagents), and (e) chromatography shown in Figure 1. Dielectric film, (f) absorbent pad, and (g) backing paper. In addition, a part of these components may be omitted if necessary. As shown in Fig. 1, (f) the absorption pad is the part that finally absorbs the specimen as the measurement object in the immunochromatography, (c) is the test line (TL), and (d) is the control line (CT). Furthermore, as described above, as conventional absorbent pads in the prior art, cellulose filter paper, paper, glass fiber, long glass fiber, etc. can be cited.

The sample pad is the part that initially receives the specimen as the measurement object in the immunochromatography. Examples of common sample pads include cellulose filter paper, paper, glass fiber, long glass fiber, acrylic fiber, nylon fiber, and various woven fabrics. In addition, pre-processing may be performed if necessary. For example, the following substances can also be processed in advance: buffers, surfactants, proteins, reagents for capturing inclusions in the specimen sample, preservatives, antibacterial agents, antioxidants, moisture absorbents, etc.

The binding pad is a part where labeled particles such as antibody sensitization labeling reagents are dried and fixed in advance. As a common bonding pad, glass fiber, long glass fiber, acrylic fiber, PET (polyethylene terephthalate, polyethylene terephthalate) fiber single component or non-woven fabric, woven fabric, etc. can be mentioned. In addition, pre-processing may be performed if necessary.

The labeling reagent fixed on the binding pad refers to a particulate substance that is insoluble in water, buffer, etc., and is loaded with pigments or dyes. The materials constituting the particles are not particularly limited. Examples of such labeling reagents include metal colloidal particles such as gold colloid, platinum colloid, silver colloid, and selenium colloid; and styrene-based latex such as polystyrene latex or acrylic acid-based Colored latex particles made by coloring latex, etc.; Colored silica particles made by coloring silicon dioxide containing a three-dimensional structure containing silicon atoms and oxygen atoms; Colored cellulose particles made by coloring cellulose; Marking reagents made of carbon black and other colored components granulated; magnetic particles, etc. In addition, the above-mentioned labeling reagent may be fluorescent particles.

The labeling reagent must carry a substance that specifically binds to the test substance, such as an antibody, and the method of carrying it is not particularly limited. For example, it can include: support by physical adsorption, support by covalent bonding, support by combination of these, and the like. The type or amount of the material carried is also not particularly limited. As the type of material carried, antibodies are the most common and preferred. In addition, as a method of loading, from the viewpoint of ease, it is preferable to use physical adsorption, and from the viewpoint of stability, performance, etc., it is preferable to use covalent bonding.

The objects that can be diagnosed using the immunochromatographic diagnostic kit of this embodiment are not particularly limited. Specific examples include the following: cancer markers, hormones, infectious diseases, autoimmunity, plasma proteins, and TDM (Therapeutic Drug Monitoring, Drug therapy monitoring), coagulation/fibrinolysis, amino acids, peptides, proteins, genes, cells, etc. More specifically, include: CEA (Carcinoembryonic antigen), AFP (Alpha fetoprotein), ferritin, β2 microglobulin, PSA (Prostate Specific Antigen) , CA19-9 (Cancer antigen 19-9, cancer antigen 19-9), CA125, BFP (Basic fetoprotein, basic fetoprotein), elastase 1, pepsinogen 1/2, fecal occult blood, urine β2 microspheres Protein, PIVKA-2 (Protein Induced by Vitamin K Absence or Antagonist-II, protein induced by vitamin K deficiency or antagonist-II), urine BTA (Bladder tumor antigen), insulin, E3, HCG (Human Chorionic Gonadotropin, human chorionic gonadotropin), HPL (Human placental lactogen, human placental lactogen), LH (Leuteinizing hormone, luteinizing hormone), HCV (Hepatitis C Virus, C virus) antigen, HBs antigen (hepatitis) B surface antigen, HBs antibody, HBc antibody (Hepatitis B core antibody), HBe antigen (hepatitis B e antigen, hepatitis B e antigen), HBe antibody, HTLV-1 (Human T-lymphotropic Virus 1, type 1 human T lymphotropic virus) antibody, HIV antibody, Toxoplasma antibody, syphilis, ASO (Anti-Streptolysin O, anti-streptococcal hemolysin O), influenza A antigen , Influenza A antibody, Influenza B antigen, Influenza B antibody, Rotavirus antigen, Adenovirus antigen, Rotavirus/Adenovirus antigen, Group A streptococcus, Group B streptococcus, Candida Bacterial antigen, CD bacteria (Clostridium difficile, Clostridium difficile), cryptococcal antigen, cholera, meningococcal antigen, granule elastase, Helicobacter pylori antibody, O157 antibody, O157 antigen, Leptospira antibody, koji Bacterial antigen, MRSA (methicillin-resistant staphyllococcus aureus, methicillin-resistant Staphylococcus aureus), RF (rheumatoid factor, Rheumatoid factor), total Ig (Immunoglobulin, immunoglobulin) E, LE (lupus erythematosus, lupus erythematosus) test, CRP (C-Reactive Protein, C-reactive protein), IgG/A/M, IgD, transferrin , Urinary albumin, urinary transferrin, myoglobin, C3/C4, SAA (serum amyloid A), LP(a) (Lipoprotein(a), lipoprotein (a)), α1-AC (α1-antichymotrypsin, α1-antichymotrypsin), α1-M (α1-microglobulin, α1-microglobulin), binding globulin, microtransferrin, APR (Acute Phase Reactants, acute phase reaction) Protein) score, FDP (Fibrin degradation product), D dimer, plasminogen, AT3 (antithrombin III, antithrombin 3), α2PI (α2-plasmin inhibitor, α2-fibrinolysis) Enzyme inhibitor), PIC (plasmin-alpha 2-plasmin inhibitor complex, plasma plasmin-α2 plasmin inhibitor complex), PAI-1 (plasminogen activator inhibitor-1, plasminogen activator first Type inhibitor), protein C, coagulation factor X3, type IV collagen, hyaluronic acid, GHb (Glycated hemoglobin) A1c, other various antigens, various antibodies, various viruses, various bacteria, various amino acids, various Peptides, various proteins, various DNA (Deoxyribonucleic Acid, deoxyribonucleic acid), various cells, various allergens, various residual pesticides, various harmful substances.

The chromatography media used in the immunochromatography diagnostic kit is not particularly limited, and various commonly used chromatography media can be used. Specifically, a nitrocellulose film can be mentioned.

Hereinafter, an example of the method of making the immunochromatographic diagnostic kit will be described. Prepare a dispersion solution of the labeling reagent adjusted to a specific concentration, add buffer and antibody, and stir for a certain period of time while adjusting the temperature to make the antibody adsorb to the labeling reagent. After stirring for a certain period of time, a binding agent is further added, and the temperature is adjusted while stirring for a certain period of time, thereby performing the adhesion of the colored cellulose particles. As the adhesive, various adhesives can be used according to the composition of the inspection target substance or specimen or the solution to dilute it. In order to wash the labeling reagent after antibody adsorption and adhesion, centrifugal separation is performed, and the supernatant liquid containing the remaining antibody and the adhesion agent is separated from the precipitated particles, and the supernatant liquid is removed by decantation. Add a liquid such as a buffer to the precipitated particles, and perform dispersion treatment with ultrasonic waves, etc., if necessary. The washing by a series of operations such as precipitation by centrifugal separation, supernatant removal, and liquid addition is performed the necessary number of times to prepare a dispersion containing a specific concentration of particles that have undergone antibody adsorption and adhesion. If necessary, protein, surfactant, sugars such as sucrose or trehalose are added to the dispersion liquid, and the obtained solution is applied to a bonding pad made of long glass fibers in a certain amount and dried to prepare a detection reagent containing portion. In addition, if necessary, apply buffer, surfactant, protein, reagents to capture inclusions in the specimen sample, preservatives, antibacterial agents, antioxidants, moisture absorbents, etc., on the regenerated cellulose continuous filament nonwoven fabric, and It is dried to prepare a sample pad. Furthermore, a chromatographic medium made of a chromatographic medium membrane to fix the antibody at a specific position, and an absorbent pad made of cellulose filter paper for absorbing the sample are prepared. It is fixed to a sheet with an adhesive part called a backing sheet, and cut to a specific size, thereby making an immunochromatographic diagnosis kit. [Example]

Hereinafter, the present invention will be explained more specifically with examples and comparative examples, but the present invention is not limited to the examples.

＜Determination of average degree of substitution＞ (i) Acidity, alkalinity Accurately weigh about 1 g of the sample (anhydrous) into a 300 mL conical flask, and add about 200 mL of water to dissolve it. Add 5 mL of 0.05 mol/L sulfuric acid to it with a pipette, boil for 10 minutes and then cool, add a phenolphthalein indicator, and titrate with 0.1 mol/L potassium hydroxide (S mL). Simultaneously carry out a blank test (B mL), using the following formula (1): Alkalinity={(B－S)×f}/weight of sample anhydrous (g)...Equation (1) {Where, f: 0.1 mol/L potassium hydroxide power price} calculated. Here, when the value of (B-S)×f is (-), the alkalinity is replaced with acidity. (ii) Average degree of substitution Accurately weigh 0.5-0.7 g of the sample (anhydrous), wrap it in filter paper, and ash in a magnetic crucible. After cooling, move it to a 500 mL beaker, add about 250 mL of water, and then add 35 mL of 0.05 mol/L sulfuric acid with a pipette, and boil for 30 minutes. Cool it, add phenolphthalein indicator, back titrate the excess acid with 0.1 mol/L potassium hydroxide, by the following formulas (2) and (3): A=(a×f－b×f1)/sample anhydrous weight (g)－alkalinity (or +acidity)...Equation (2) Degree of substitution=(162×A)/(10000－80×A)...Equation (3) {In the formula, A: the amount of 0.05 mol/L sulfuric acid (mL) consumed by the bound alkali in 1 g of the sample, a: 0.05 mol/L sulfuric acid consumption (mL), f: 0.05 mol/ The price of L sulfuric acid, b: 0.1 mol/L potassium hydroxide titration (mL), f1: 0.1 mol/L potassium hydroxide) Calculate the degree of substitution, and calculate the average value (N=3 or more) ) As the average degree of substitution.

<Liquid absorption C (g/100 cm ² ))> The liquid absorption of the sheet structure is measured under the conditions that allow free morphological changes. Specifically, the sheet structure was cut into 5 cm×5 cm and placed in a petri dish. Thereafter, physiological saline of 50 times the weight of the sample was heated to 37°C, then added to it, and allowed to stand in a constant temperature machine at 37°C for 30 minutes. Then, according to the weight before and after the culture, use the following formula (4): Liquid uptake C(g/100 cm ² )=(B－A)×4… formula (4) {where, A: drying before immersion The weight in the state (g), B: the weight (g) after 30 minutes of incubation} Calculate the liquid uptake.

<Weight per unit area D (g/m ² )> ^{After drying the non-woven fabric with an area of 0.5 m 2} or more at 105°C to reach a certain weight, place it in a constant temperature room at 20°C and 65% RH (Relative humidity) 16 Measure the weight for more than hours, and measure the weight per unit area of the non-woven fabric.

＜Thickness＞ The thickness refers to the value obtained by the thickness test in accordance with JIS-L1096, and the load is set to 1.96 kPa.

＜Release time (minutes)＞ Prepare a complex array of test strips with 4 mm wide x 25 mm long absorbent pads stacked on a chromatographic medium containing nitrocellulose with a width of 4 mm x 25 mm in an aligned manner. A group of 20 μL was added to the entire pad of the absorbent pad of each test piece. After the time T1 (minutes) has elapsed since the end of the dripping of the physiological saline, remove the absorption pad from the chromatographic medium for a group of test pieces, and visually observe the surface state of the chromatographic medium. At this time, when it is confirmed that there is a part of the chromatographic medium whose color changes due to being wetted by physiological saline, the release time of the absorbent pad is set to T1 (minutes). On the other hand, when it is not confirmed that there is a part where the color changes, when the time T2 (minutes) (where T1<T2) has elapsed since the end of the dripping of the physiological saline, it is different from the elapsed time T1 (minutes). One set of test pieces of the later confirmed test piece, the color change of the chromatographic medium surface is judged by the same method as the above. Repeat the above operations until the color change caused by wetting is confirmed on the surface of the chromatography medium, thereby determining the release time. However, when the color change of the chromatographic medium surface caused by the wetting of the liquid is not confirmed at any time from the end of adding the physiological saline to the 900 minutes, the release time of the absorbent pad is set to 900 minutes .

＜Background of immunochromatographic diagnosis kit (BG coloring)＞ Place the immunochromatographic diagnostic kit cut to an appropriate width into the plastic case. Next, PBS (Phosphate Buffered Saline) containing 1% by weight of BSA (Bovine Serum Albumin) 66 mM and pH 7.4 was prepared as a negative specimen. Using the obtained diagnostic kit put in the outer casing, drop 100 μL of the negative sample into the sample dropping part of the diagnostic kit. After 5 minutes, use the immunochromatography reader C10066-10 manufactured by Hamamatsu Photonics. , Measure the color intensity at one point between TL and CL (unit: mABS). Here, the case where the color development intensity is 20 mABS or more is judged to be BG coloring. The reason why it is set to 20 mABS or more here is that if it is 20 mABS or more, the coloring can be confirmed visually.

＜Confirmation of countercurrent of immunochromatographic diagnosis kit＞ Regarding the confirmation of the countercurrent, it is carried out by the same method as the above-mentioned background confirmation experiment. Put the immunochromatographic diagnostic kit cut to an appropriate width into the plastic case. Next, prepare 66 mM PBS with a pH of 7.4 containing 1% by weight BSA as a negative specimen. Using the obtained diagnostic kit put in the outer casing, drop 100 μL of the negative sample into the sample dropping part of the diagnostic kit, and after 20 minutes, measure the color intensity at 1 point between TL and CL ( The unit is mABS). Here, the case where the color development intensity is 20 mABS or more is judged to be BG coloring (determination is marked as ×). The uncolored case is recorded as ○.

＜Deviation of color intensity of test line (TL)＞ For the measurement of the TL color intensity, 100 μL of the positive sample was dropped into the sample dropping part of the diagnostic kit in the same manner as above, and the color intensity of the test line after 5 minutes was measured by the immunochromatographic reader (mABS). ). This measurement was performed 30 times in total, and the average color development intensity (mABS) was taken as the TL color development intensity. At the same time, the standard deviation of the TL color intensity is obtained at the same time, and the index %CV representing the reproducibility is given by the following formula (5): %CV=(standard deviation of TL color intensity/TL color intensity)×100……Equation (5) Figure out.

[Reference example 1 (Sample 1-15)] The regenerated cellulose continuous fiber sheet structure (copper ammonia sheet structure) (samples 1-12), cupra short fiber nonwoven fabric (sample 13), lyocell short fiber nonwoven fabric (sample 14), and rayon Short-fiber non-woven fabric (sample 15) (width 20 cm, weight per unit area, thickness 0.2 ~ 7.0 mm): 100 g is placed in the reaction vessel, after which, sodium hydroxide-containing ethanol aqueous solution (water: 875 g, After ethanol 875 g, NaOH: 162.5 g), the mixture was stirred at 35°C for 30 minutes. Secondly, after the reagents in the reaction vessel are discharged, an ethanol aqueous solution containing sodium monochloroacetate (water 300 g, ethanol 960 g, sodium monochloroacetate 122.5 g) is added, and the mixture is stirred at 30 or 50°C for 1-12 hours. Thereafter, drying is performed to obtain a carboxymethylated sheet-like structure. After adjusting the pH of the sheet-like structure obtained above to 6.0-8.0 with an aqueous ethanol solution containing acetic acid (acetic acid: 37.5 g, distilled water: 375 g, ethanol: 875 g), 1375 g of 70 wt% ethanol aqueous solution was used It was washed once, washed once with 1250 g of 90 wt% ethanol aqueous solution, and replaced with alcohol twice with 1250 g of 100 wt% ethanol. Then, immerse in 1250 g (1-100 wt%) ethanol solution containing acetic acid or aqueous ethanol solution (2-5 wt%) containing hydrochloric acid. After stirring for 1 hour, wash with 1375 g 70 wt% ethanol aqueous solution. Wash once with 1250 g of 90 wt% ethanol aqueous solution, and perform alcohol replacement twice with 1250 g of 100 wt% ethanol, dry, and then put it at 105°C, 6 h or 120°C, 3 h Hot air dryer to obtain sheet structure. The average degree of substitution, capture and release index, weight per unit area, thickness, and liquid absorption of the obtained sheet structures (samples 1 to 15) are shown in Table 1 below. These samples 1-15 were used as absorbent pads.

[Preparation of Antibody Sensitized Gold Colloidal Particles] Add 600 μL of phosphate buffer (50 mM, pH 7.0) to 2500 μL of gold colloidal particle suspension (manufactured by Tanaka Precious Metals, average particle size 40 nm, particle concentration 0.006 wt%, average particle size 40 nm), and then add 200 μL of 0.1% aqueous solution of anti-hCG-α mouse antibody (manufactured by Fitzgerald, monoclonal antibody) was stirred with a vortex mixer. Then, stirring was performed for 10 minutes while adjusting the temperature at 25°C. Add 300 μL of 1% PEG (Polyethylene Glycol) aqueous solution and 600 μL of 10% BSA aqueous solution (pH 9.0, containing 50 mM boric acid) to the above suspension, and stir with a vortex stirrer. After that, a centrifugal separation operation (10000 g, 30 minutes) was performed, and the supernatant was removed. 1% BSA aqueous solution (containing 0.05% PEG, 150 mM NaCl, pH 8.2 and 20 mM trimethylolaminomethane) 11000 μL was added to the residue, and stirred with a vortex stirrer. After that, a centrifugal separation operation (10000 g, 30 minutes) was performed, and the supernatant was removed. To the residue, 900 μL of 1% BSA aqueous solution (containing 0.05% PEG, 150 mM NaCl, pH 8.2 and 20 mM trimethylolaminomethane) was added, and ultrasonic treatment was performed for 30 seconds.

[Impregnation and drying of the labeling reagent of the bonding pad] Cut the long glass fiber bonding pad (#8951 manufactured by Ahlstrom) into a shape with a height of 10 mm and a length of 300 mm. Thereafter, 1020 μL of the antibody-sensitized gold colloidal particle dispersion was uniformly applied, and dried at 50°C for 60 minutes.

[Pretreatment of sample pad] The sample pad (C048 manufactured by Millipore) was immersed in a large excess of PBS buffer (66 mM) containing 2.0% by weight of BSA (A7906 manufactured by Sigma-Aldrich) and 2.0% by weight of Tween-20 (registered trademark) , PH 7.4), remove excess liquid and dry at 50°C for 60 minutes. Then cut into a shape with a height of 18 mm and a length of 300 mm.

[Preparation of nitrocellulose membrane coated with capture antibody] The nitrocellulose membrane (SHF0900425 manufactured by Millipore) was cut into a shape with a height of 25 mm and a length of 300 mm. Using a liquid coating device (300DS manufactured by Wu Zou High-Tech Co., Ltd.), a PBS solution (66 mM, pH 7.4) containing 0.1% by weight of anti-hCG-β mouse antibody (6601 manufactured by MedixBiochemica) was added to 0.1 μL/ The ratio of mm is applied to the part with a height of 7 mm. Then, a PBS solution (66 mM, pH 7.4) containing 0.1% by weight of an anti-mouse-rabbit antibody (Z0259 manufactured by Daco) was applied to a portion with a height of 12 mm at a rate of 0.1 μL/mm. Then, it was dried at 37°C for 30 minutes.

[Preparation of immunochromatographic diagnostic kit] Laminate the prepared nitrocellulose membrane coated with capture antibody on the backing card (AR9020 manufactured by Adhesives Reserch), the absorbent pad (samples 1-15) manufactured in Reference Example 1, and the binding pad containing labeling reagent , Sample pad. Then use a cutting machine to cut into a width of 5 mm to obtain an immunochromatographic diagnostic kit with a width of 5 mm and a height of 60 mm.

[Examples 1-15] [Performance evaluation of immunochromatographic diagnostic kit] Each of the samples 1 to 15 shown in Table 1 below was used as an absorbent pad for evaluation. In the performance evaluation of the immunochromatographic diagnostic kit with a width of 5 mm and an absorbent pad with a thickness of 0.2 mm or more, the expandable volume of the developing solution is about 80-120 μL, so 100 μL is actually expanded Evaluation. In addition, if the set width is set to 2.5 mm, or the absorbent pad with a thickness of less than 0.2 mm is used, the expandable amount of the developing solution is about 30 to 80 μL, so 50 μL is actually expanded for evaluation. The evaluation results are shown in Table 2 below. The deviations in any diagnostic kit were small and did not cause backflow. In addition, there are fewer detached fibers in any diagnostic kit, which ensures the safety of the procedure.

[Table 1] material Average degree of substitution Capture and release index Weight per unit area (g/m ² ) Thickness(mm) Liquid absorption (g/100 cm ² ) Sample 1 Regenerated cellulose continuous filament 0.40 0.06 100 0.9 18 Sample 2 0.40 0.25 20 0.2 6 Sample 3 0.40 0.23 50 0.4 14 Sample 4 0.40 0.07 80 0.5 16 Sample 5 0.40 0.02 150 1.5 31 Sample 6 0.40 0.03 180 2.0 42 Sample 7 0.07 0.47 100 0.9 7 Sample 8 0.20 0.08 100 0.9 10 Sample 9 1.30 0.04 100 0.9 39 Sample 10 0.40 0.01 200 0.4 twenty four Sample 11 0.40 0.01 300 0.7 39 Sample 12 0.40 0.01 370 1.1 48 Sample 13 Cupra short fiber 0.40 0.26 180 2.0 38 Sample 14 Lyocell staple fiber 0.40 0.07 180 5.0 12 Sample 15 Rayon staple fiber 0.40 0.05 180 7.0 11

[Table 2] Immunochromatographic evaluation results BG coloring (after 5 minutes, mABS) With or without countercurrent TL strength (mABS) Deviation (%CV) Example 1 Sample 1 2.3 ○ 323 2.5 Example 2 Sample 2 1.7 ○ 325 2.4 Example 3 Sample 3 2.5 ○ 308 3.5 Example 4 Sample 4 1.3 ○ 315 3.3 Example 5 Sample 5 1.5 ○ 312 3.2 Example 6 Sample 6 3.4 ○ 264 2.5 Example 7 Sample 7 6.0 ○ 270 1.9 Example 8 Sample 8 1.7 ○ 316 2.5 Example 9 Sample 9 8.8 ○ 250 2.2 Example 10 Sample 10 2.1 ○ 306 2.9 Example 11 Sample 11 1.9 ○ 296 2.2 Example 12 Sample 12 2.4 ○ 327 3.1 Example 13 Sample 13 12.5 ○ 328 3.3 Example 14 Sample 14 16.3 ○ 333 2.2 Example 15 Sample 15 18.5 ○ 322 2.5

[Sample 16] A continuous long-fiber regenerated cellulose sheet structure (copper ammonia sheet structure) (width 20 cm, ^{weight per unit area of 100 g/m 2} and thickness 0.9 mm) was prepared.

[Sample 17] Prepare regenerated cellulose continuous fiber sheet structure (copper ammonia sheet structure) (width 20 cm, 100 g/m ² unit area weight, thickness 1.0 mm), and increase the amount of monochloroacetic acid used The amount of use was adjusted so that the degree of substitution was increased, and except for that, the treatment was performed in the same manner as in Reference Example 1 to obtain a sheet-like structure.

[Sample 18] Prepare regenerated cellulose continuous long fiber sheet structure (copper ammonia sheet structure) (width 20 cm, 300 g/m ² unit area weight, thickness 4.0 mm). In addition, with reference to The same method as in Example 1 was carried out to obtain a sheet-like structure.

[Sample 19] A rayon staple fiber sheet structure (width 20 cm, 300 g/m ² weight per unit area, thickness 12.0 mm) was prepared, and except for this, the same treatment as in Reference Example 1 was performed to obtain a sheet structure .

[Sample 20] A rayon staple fiber sheet structure (width 20 cm, 430 g/m ² weight per unit area, thickness 6.7 mm) was prepared, and except for this, the same treatment as in Reference Example 1 was performed to obtain a sheet structure .

[Comparative Examples 1-7] [Performance Evaluation of Immunochromatographic Diagnostic Kit] The samples 16-20 shown in Table 3 below were used for evaluation. Use the above-mentioned samples 16-20 and long glass fiber absorbent pads (74 g/m ² unit area weight, thickness 0.5 mm), cellulose absorbent pads (180 g/m ² unit area weight, thickness 0.51 mm), except for this Otherwise, the evaluation was carried out by the same method as in Example 1. The evaluation results are shown in Table 4 below. As a result, the sample 16 without carboxymethylation caused a backflow, and the gel of the absorbent pad collapsed during the unfolding process of the sample 17 with an average degree of substitution exceeding the scope of this case, and the deviation became larger. The deviation of the inspection results of the sample 18 due to the excessively high capture and release index. Sample 19 was too thick and its flexibility was impaired, and it could not be firmly attached, and the deviation became large. The sample 20 had too much weight per unit area, so its flexibility was impaired, its operability was significantly reduced, it could not be firmly attached, and its deviation increased. The long glass fiber absorbent pad and the previously used cellulose absorbent pad produce countercurrent flow. In addition, if the long glass fiber is used, there are many detached fibers, and it is difficult to ensure the safety in the process.

[table 3] material Average degree of substitution Capture and release index Weight per unit area (g/m ² ) Thickness(mm) Liquid absorption (g/100 cm ² ) Sample 16 Regenerated cellulose continuous filament - 6.00 100 0.9 6 Sample 17 1.80 0.14 100 1.0 41 Sample 18 0.40 1.07 300 4.0 48 Sample 19 Rayon staple fiber 0.40 0.33 300 12.0 45 Sample 20 0.40 0.30 430 6.7 39

[Table 4] Immunochromatographic evaluation results BG coloring (after 5 minutes, mABS) With or without countercurrent TL strength (mABS) Deviation (%CV) Comparative example 1 Sample 16 28.8 X 110 18.3 Comparative example 2 Sample 17 3.5 ○ 340 20.4 Comparative example 3 Sample 18 5.5 ○ 298 22.5 Comparative example 4 Sample 19 3.5 ○ 380 19.9 Comparative example 5 Sample 20 8.7 ○ 334 17.2 Comparative example 6 Made of long glass fiber 3.4 X 340 18.9 Comparative example 7 Cellulose pad 25.6 X 130 31.0 [Industrial availability]

The immunochromatographic diagnostic kit using the absorbent pad for the immunochromatographic diagnostic kit of the present invention has less deviation in color development intensity and is excellent in reproducibility. Furthermore, backflow can also be prevented, and therefore, it can be used as an absorbent pad for various immunochromatographic diagnostic kits.

(a): Sample pad (b): Binding pad (including antibody sensitization labeling reagent) (c): Test line (TL) (d): Control line (CT) (e): Chromatography medium membrane sample pad (f): Absorbent pad (g): Backing paper

Fig. 1 is a cross-sectional view of an immunochromatographic diagnostic kit as an embodiment of the present invention.

(a): Sample pad

(b): Binding pad (including antibody sensitization labeling reagent)

(c): Test line (TL)

(d): Control line (CT)

(e): Chromatography medium membrane sample pad

(f): Absorbent pad

(g): Backing paper

Claims (6)

An absorbent pad for an immunochromatographic diagnostic kit, characterized in that it contains carboxymethylated cellulose fibers, and the average substitution of hydroxyl groups in the glucose units constituting the carboxymethylated cellulose fibers The degree is 0.05 or more and 1.5 or less. The absorbent pad for the immunochromatographic diagnostic kit of claim 1, wherein the capture and release index of the pad is 0.5 or less. Such as claim 1 or 2 of the absorbent pad for immunochromatographic diagnostic kits, wherein the weight per unit area of the pad is 10 g/m ² or more and 400 g/m ² or less, and the thickness is 0.03 mm or more and 10.00 mm or less. The absorbent pad for an immunochromatographic diagnostic kit according to any one of claims 1 to 3, wherein the absorbent pad when the pad is immersed in physiological saline is 5 g/100 cm ² or more and 50 g/100 cm ² or less. The absorbent pad for an immunochromatographic diagnostic kit according to any one of claims 1 to 4, wherein the pad is in the form of a single-layer sheet or a laminated sheet. An immunochromatographic diagnostic kit comprising the absorbent pad for the immunochromatographic diagnostic kit according to any one of claims 1 to 5.

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