JP2010181346A - Sample pad for examination kit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide more inexpensively an examination kit utilizing immunochromatography, especially a sample pad used for a lateral flow method examination kit, which is a sample pad having an indicator function enabling a tester to determine easily sufficient liquid wettability, not blocking color development for diagnosis, and capable of determining easily by not only color development but also character display or the like whether a dropping amount is sufficient or not, and an examination kit using the sample pad. <P>SOLUTION: In the sample pad for the examination kit, which is a sample pad constituting an examination kit for an extracorporeal diagnostic agent, a coloring layer is arranged on the back side of an absorber, and ΔL1 of the absorber is 20 or less and ΔL2 thereof is 30 or more. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a sample pad for an in vitro diagnostic agent test kit and a test kit using the same.

  In an in vitro diagnostic kit (hereinafter simply referred to as a test kit), an immunological test using an antigen-antibody reaction is generally employed.

  Specifically, the kit is pre-impregnated with a labeled antibody labeled with a color-identifying substance such as an enzyme, metal colloid, or colored latex, and a sample such as blood, urine, sputum, nasal discharge, or cell is dropped. Later, the antigen in the sample and the labeled antibody form a specific complex that can be compared to a key and a keyhole by an antigen-antibody reaction, and then the complex is fixed in place by the immobilized antibody previously applied to the kit. Color. The presence / absence or degree of coloration is measured visually or as an optical change, and the qualitative analysis or quantitative analysis of the antigen in the sample is performed.

  By using the above test method, it is possible to easily and quickly inspect and diagnose the presence or absence of virus infection, pregnancy determination, disease confirmation, presence or absence of harmful substances, and presence or absence of allergens in food. These are developed and marketed as test kits (see Patent Document 1).

  In such a test kit, the sample pad arranged at the bottom of the collection hole absorbs a sufficient amount of sample for the measurement when the sample such as urine is dropped first, and promptly performs later steps (downstream). Side)). As the sample pad, glass fiber, filter paper, water absorbent paper, felt-like fiber body, non-woven fabric, absorbent cotton and the like are used.

In an inspection using such a test kit, it is necessary to collect a sufficient amount of sample for measurement, but it is difficult to grasp the amount of sample collected at first glance. There was a problem that the measurer could not easily determine whether it was sufficient.
In a test kit, a method that allows the measurer to easily determine the state of sample collection (hereinafter referred to as an indicator function) by using chemicals to cause the sample pad portion to develop color with water in the sample such as urine Is being considered.

Specifically, examples of the reagent that causes color change upon contact with moisture absorption and aqueous solution include dehydrated transition metal salts such as CuSO ₄ and Co (NO ₃ ) ₂ , pH indicators, and the like. There is a method in which the sample pad portion is impregnated and the sample pad portion is colored by a sufficient liquid collection.

  However, a reagent that changes color due to moisture absorption is difficult to handle during normal temperature and normal pressure manufacturing processes and storage. Also, pH indicators are often unsuitable for use because the urine pH is weakly acidic to weakly basic in the normal range. Furthermore, there is one that utilizes the property that fluorescein or sodium fluorescein (uranin) changes in color tone from orange red to fluorescent green when wetted with water (for example, see Patent Document 2). The process of impregnating and drying the resin on the test paper is necessary, which is costly, because it uses chemicals, it is necessary to thoroughly examine whether it will affect the subsequent judgment, and the color of the indicator will be specified. There was a problem.

No. 7-14892 JP-A-6-300751

  The present invention is a sample pad used in a test kit utilizing immunochromatography, particularly a lateral flow method test kit, in which a tester can easily determine sufficient liquid wettability, and coloration for diagnosis. A sample pad with an indicator function that can easily determine whether the amount of dripping is sufficient not only by color development but also by displaying characters, etc., and a test kit using the same The purpose is to provide in.

  As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved if the sample pad constituting the test kit has a structure in which a colored layer is disposed on the back side of the absorber. The present invention has been made.

  The sample pad of the present invention uses a specific absorber that allows the state of the colored layer to be seen through by collecting the collected liquid, so that the absorber hides the colored layer in the dry state, and develops color due to water absorption in the water absorption state. You can easily determine whether or not you are wet.

That is, the present invention is as follows.
1. A test pad sample pad comprising a test kit for an in-vitro diagnostic agent, wherein a colored layer is disposed on the back side of the absorber, and ΔL1 of the absorber is 20 or less and ΔL2 is 30 or more.

2. ^2. The test kit according to 1 above, wherein the absorbent has a cellulose fiber mixing ratio of 50% or more, a basis weight of 75 to 200 g / m ² , and a density of 0.05 to 0.5 g / cm ³ . Sample pad.

3. ^3. The test kit sample pad according to 2 above, wherein the absorbent has a basis weight of 90 to 150 g / m ² and a density of 0.1 to 0.3 g / cm ³ .
4). A test kit for an in vitro diagnostic agent in which the sample pad according to any one of 1 to 3 is disposed.

  The sample pad for the test kit of the present invention should have an indicator function of coloring by a sufficient amount of liquid absorption by arranging a colored layer on the back side of a specific absorber that has different see-through performance when dried and when moisture is absorbed. Can do. Therefore, at the time of the inspection using the inspection kit, the measurer can easily determine whether or not the liquid absorption amount is sufficient for the measurement.

It is a figure (perspective view before an assembly) which shows the structure roughly about an example of a test kit.

The present invention will be described in detail below.
In the present invention, the test kit is a test kit using an in vitro diagnostic agent. Specifically, a liquid sample (such as urine) is collected, the sample is brought into contact with a labeled antibody in the kit, and the presence or degree of coloration due to the reaction can be measured visually or as an optical change. For example, it has the structure shown in FIG.

  In the present invention, other members such as the shape of the test kit, the membrane carrier, the labeled antibody, the conjugate pad forming the inner sheet, the water absorbing pad, etc. can be used and are not limited. In addition, the method of using the test kit is generally when the specimen is directly applied to the sample pad portion, but other methods, for example, a method of measuring after collecting the specimen in a cup or the like may be used.

  Hereinafter, a typical configuration of the test kit will be described with reference to FIG. In the inspection kit, an inner sheet 4 having a function of collecting and coloring is disposed inside the housing 1. The inner sheet is composed of a liquid collection part (sample pad 5), a reagent containing part (conjugate pad 6), a determination display part (membrane 7), and a water absorption part / drying part (water absorption pad 8) from the upstream of the liquid flow. Each has the following functions.

(1) Liquid collection part This is the part where the specimen is supplied from the liquid collection hole to the liquid collection part (sample pad), and the method of liquid collection is not particularly limited. For example, the liquid is collected by directly applying a sample (such as urine), dropping the sample once collected with a dropper, or attaching the sample to the collected sample. The specimen collected on the sample pad is immediately moved downstream.

(2) Reagent-containing part A labeled first reagent that specifically binds to a test substance (for example, hCG) that may be present in a specimen (for example, a first anti-hCG that is labeled with gold colloid) Antibody) and lyophilized. When a test substance is contained in the sample absorbed by the sample pad, this test substance is combined with the labeled first reagent and developed on the next determination display section (membrane).

(3) Determination display unit The determination display unit (membrane) is formed from a chromatographic medium such as nonwoven fabric, filter paper, glass fiber filter paper, nylon, or nitrocellulose, and is a second reagent that specifically binds to a test substance ( For example, a second anti-hCG antibody) is applied and fixed in advance. Therefore, in the determination display unit, when the test substance is contained in the specimen, the test substance bound to the labeled first reagent is captured, and the labeling substance (for example, gold colloid) is attached. It turns reddish purple.

  If necessary, a reaction end display part may be provided. For example, if a water-absorbing filter paper coated with a pH indicator such as phenolphthalein or Congo red is placed, when the specimen penetrates to the reaction end indicator, it reacts with the pH indicator and becomes colored, Indicates that the reaction is complete.

(4) Water absorption part / drying part The water absorption part is provided for the purpose of absorbing the sample liquid from the upstream. Without the water absorption part, when there is a large amount of sample liquid, there is a possibility that normal inspection cannot be performed due to rewetting.

  The drying section is formed of, for example, a desiccant processed into a sheet shape with calcium chloride or silica gel and pulp. This drying section is also provided for the purpose of maintaining the ability of each reagent. Although a drying part is not necessarily required, it is preferable to provide a drying part for the purpose of preventing inactivation due to moisture absorption of the reagent in the kit.

  The immunochromatographic assay that constitutes such an inner sheet is made of a double-sided tape or a spray paste, etc., for the materials constituting the liquid collection part, reagent-containing part, determination display part, reaction end display part, and water absorption part / drying part. It is possible to manufacture by cutting on a base material, or after sticking on a base material that has been adhesively processed using various adhesives.

  Examples of the base material include moisture-impermeable materials such as polyvinyl chloride, polyethylene, polypropylene, polyester, polystyrene, and acrylic polymer, and paper coated with the moisture-impermeable material.

  The above immunochromatographic assay is generally housed in a housing in consideration of handling. The material of the housing is not particularly limited. For example, polyvinyl chloride, polypropylene, polyethylene, polystyrene, acrylic acid polymer, or the like is used.

  In the sample pad for the test kit of the present invention, the specimen is urine, stool suspension, and other body fluids, and the test substance is hCG, LH, FSH (follicle stimulating hormone), TSH (thyroid stimulating hormone), hemoglobin, It is particularly effective for sugars and other proteins, and the type of reagent, the material containing the reagent in advance, its position, the method of inclusion, etc. can be arbitrarily selected depending on each test substance.

The sample pad for a test kit of the present invention has a structure that provides water absorption characteristics as a sample pad and an indicator function that can easily determine sufficient liquid wetting during measurement.
In order to develop water absorption characteristics, it is preferable to use a fiber structure as the absorbent body. The water absorption characteristics of an absorbent body made of a fiber structure are determined by the weight of the structure, the density, the fiber material, and the like. However, as the performance of the sample pad, an appropriate amount of temporary water retention and liquid delivery are important.

Basis weight is preferably 75~200g / ^{m 2,} more preferably 90~150g / ^{m 2.} If the basis weight is too large, the temporary water retention amount becomes too large relative to the amount of the dropped liquid, and the sample pad holds the liquid, and the subsequent (downstream) process (antibody release at the conjugate pad, antigen-antibody complex) The liquid passing to (formation) becomes insufficient, and as a result, the amount of liquid sufficient for measurement is insufficient. Also, if the basis weight is too small, the temporary water retention amount will be too small, and when wet with the liquid at the time of measurement, the liquid will overflow from the sample pad and it will not be possible to secure a sufficient liquid volume. The amount of liquid is insufficient.

The density is preferably 0.05 to 0.5 g / cm ^3, more preferably 0.1 to 0.3 g / cm ^3. If the density becomes too high, the fibers are in a dense state, which makes it difficult for the test liquid to flow, resulting in poor liquid flow to the next process. When wetted with liquid during measurement, the liquid overflows from the pad. As a result, a sufficient amount of liquid cannot be secured.

The material of the sample pad needs to be hydrophilized, but the hydrophilization method may be a conventional method such as impregnation with a surfactant. If the material is hydrophobic, it repels moisture when the liquid is dropped, and the member cannot absorb liquid smoothly.
The indicator function is exhibited by setting the state of arrangement of the absorber and the colored layer, and ΔL1 and ΔL2 of the absorber within an appropriate range.

  The sample pad for a test kit of the present invention is characterized in that a colored layer is disposed on the back side of the absorber. The back side of the absorber is the surface opposite to the surface (usually facing the liquid collection hole) of the inspection kit. In the case where the specimen is collected from the upper liquid collection hole in the state where the test kit having the structure shown in FIG. 1 is laid, an absorber is disposed on the upper surface of the sample pad, and a colored layer is disposed therebelow. good.

  The absorber constituting the sample pad of the present invention is characterized in that ΔL1 and ΔL2 described later are in a specific range.

  ΔL1 is calculated by the following formula (1) using a spectrophotometer, and the difference between the L1 value obtained by measuring the color with the absorber superimposed on the white plate and the L2 value obtained by measuring the color with the absorber superimposed on the black plate. As ΔL1 is smaller, the colored layer on the backside of the absorber is less transparent during drying. In the present invention, ΔL1 of the absorber needs to be 20 or less, and preferably 15 or less. If ΔL1 is too large, the absorbent body is transparent before being wetted with the liquid, so that it is difficult to determine the liquid wettability when wetted with the liquid.

  ΔL2 is calculated by the following equation (2): the difference (ΔL2 value) between the L3 value measured by superposing the absorber on the white plate after water absorption and the L4 value measured by superposing the absorber on the black plate To do. As ΔL2 is larger, it means that the colored layer on the back surface of the absorber after water absorption is transparent. In the present invention, ΔL2 of the absorber needs to be 30 or more, and preferably 34 or more. If ΔL2 is too small, the color will be insufficient when wet with the liquid, making it difficult to determine the liquid wettability.

ΔL1 = L1-L2 (1)
ΔL2 = L3-L4 (2)

  An absorber in which ΔL1 and ΔL2 are in the above ranges can be obtained by appropriately adjusting the structure of the absorber and the type of fiber constituting the absorber. That is, the basis weight and density of the absorber can be appropriately changed depending on the amount of liquid absorbed, the housing size of the kit, and the like.

  The fibers forming the absorber may be short fibers or long fibers, and cellulose fibers are particularly preferably used, and examples thereof include cotton, pulp, hemp, cupra, viscose rayon, polynosic rayon, and lyocell. Moreover, the absorber may be comprised only by the cellulose fiber, and may contain hydrophobic fibers, such as a polyamide-type fiber, a polyolefin-type fiber, a polyester-type fiber, an acrylic fiber, and a polyurethane-type fiber.

  The cellulose mixing ratio of the absorber is preferably 50% or more, more preferably 80% or more. As a method for mixing cellulose, the cellulose fiber and the hydrophobic fiber are mixed in advance, and can be formed into a sheet by a known method such as a needle punch method, a water punch method, an air raid method, a papermaking method, or a binder method.

  Further, it may contain an agent for preventing the adsorption of a specific substance, a surfactant for controlling hydrophilicity, a fiber fixing resin, a pigment, a dye, and the like. Moreover, if an absorber part has hydrophilic property, a form will not be specifically limited, For example, a fabric, a woven fabric, a knitted fabric, a nonwoven fabric etc. are mentioned.

  The colored layer is not particularly limited as long as it is a colored material or a material on which characters or symbols are printed. Examples of the material of the colored layer include cellulose fiber, a combination of cellulose fiber and hydrophobic fiber, a hydrophilic fiber fabric subjected to hydrophilic treatment, woven fabric, knitted fabric, non-woven fabric, colored paper, film, and the like. It is good also as a colored layer by coloring the absorber bottom face in a housing. The coloring method is not particularly limited, and examples thereof include coloring with dyes, coloring with pigments, coloring by kneading dyes, and the like. As the dye or the like, a dye that does not adversely affect the subsequent process due to contact with the specimen or the like and does not dissolve the color of the colored layer may be selected. When the colored layer is hydrophobic, the conjugate pad must not be disposed below the colored layer in order to send the solution to the subsequent step.

  The structure in which the absorber and the colored layer are arranged includes not only the case where the absorber is bonded, but also a structure in which the absorber and the colored layer are overlapped and integrated in the inspection kit when the kit is configured. The bonding method is not particularly limited, but it is necessary to carry out by a method that does not impair liquid permeability and water absorption, and a method of heat bonding using hot melt powder such as polyethylene or ethylene vinyl acetate, or a net-like sheet And a method of partially adhering acrylic resin, PVA resin or the like as an adhesive, a method of physically entanglement and integration with a needle punch, a water punch, or the like.

  Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto. Moreover, the measurement method, evaluation method, etc. in the examples are as follows.

(1) Thickness (mm)
The thickness under a pressure of 1.96 N / mm ² was measured using a thickness meter.

(2) Weight per unit (g / m ² )
After drying 0.05 m ² or more fibrous structures of the area to constant weight at 105 ° C., 20 ° C., allowed to stand in a thermostatic chamber of RH 65% 16 hours or more and the weight thereof was measured, the weight per 1 m ² Asked.

(3) Density (g / cm ³ )
It calculated from said thickness and basis weight.

(4) ΔL1, ΔL2
Using a spectrophotometer (manufactured by Gretag Macbeth: Color-Eye 7000A), it was measured and calculated by the method described above.

(5) Evaluation of indicator function Copy paper on which characters of 9-point, black, Mincho font are printed is used as a colored layer, and the absorber is bonded to the colored layer using a commercially available spray paste, 10 mm x 40 mm sample pad And water was dropped from the absorber side with a 400 μl micropipette.

  By visual judgment of five inspectors engaged in fiber research, determine how the letters look before and after water absorption (the letters are not seen through before water absorption, and the letters are visible through water absorption) The indicator function was evaluated.

○: Characters are not visible before water absorption, characters are visible after water absorption △: Characters are visible before water absorption, characters are not visible after water absorption ×: Characters are visible before water absorption, or even after water absorption I can't see the letters

(6) Temporary water retention A 10 mm × 40 mm sample pad prepared in advance is placed in the housing of a commercial inspection kit having the structure shown in FIG. 1, and 400 μl of water colored with blue ink is dropped into the center of the sample pad with a micropipette. At this time, it was visually judged whether the liquid overflowed.

○: Absorbed quickly without overflowing △: Although liquid does not overflow, liquid is hard to be absorbed ×: Liquid overflows when dropped

(7) Liquid permeability A 10 mm × 40 mm sample pad prepared in advance is placed in the housing of a commercial inspection kit having the structure shown in FIG. 1, and 400 μl of water colored with blue ink is dropped with a micropipette at the center of the sample pad. Thereafter, whether or not the liquid smoothly moved to the subsequent step (conjugate pad) was determined by the time until the entire conjugate pad was colored.

○: The liquid moves within 5 seconds. Δ: The liquid moves within 10 seconds. X: It takes longer than 10 seconds for the liquid to move.

(8) Comprehensive judgment as a sample pad with indicator function ○: When there is no x among the indicator function, temporary water retention, and liquid permeability x: There is one x among the indicator function, temporary water retention, liquid permeability When

Next, members and test solutions used for evaluation of the examples of the present invention will be described.
In the examples, the measurement was performed using each member of the commercial ovulation day test kit having the structure shown in FIG. The inspection kit includes a liquid collection part (sample pad), a reagent containing part (conjugate pad), a determination display part (membrane), and a water absorption part / drying part (water absorption pad) from the upstream of the liquid flow.

[Example 1]
A cellulose non-woven fabric (made by Asahi Kasei Fibers: trade name “Benlyse”) having a basis weight of 110 g / m ² , a density of 0.11 g / cm ³ , a density of 0.11 g / cm ³ , ΔL1 = 13, ΔL2 = 37, and a cellulose mixture ratio of 100% is used. A commercially available copy paper on which 9 points, black, and Mincho font were printed was used.

The absorbent body and the colored layer were bonded together with a commercially available spray paste (trade name “Spray paste 55 color” manufactured by 3M) and cut into (10 mm × 40 mm) to obtain a sample pad.
The obtained sample pad was set in the above-mentioned commercial inspection kit from which the sample pad portion was removed in advance and evaluated. As a result, the indicator function, temporary water retention, and liquid permeability were both good and excellent as a sample pad with an indicator function.

[Examples 2 to 8]
A sample pad was prepared by integrating the absorbent body and the colored layer in the same manner as in Example 1 except that an absorbent body having a basis weight, density, ΔL1, ΔL2, and cellulose mixture ratio adjusted as shown in Table 1 was used. ,evaluated. The results were as shown in Table 1. That is, the indicator function, temporary water retention, and liquid permeability were ○ to Δ, which was excellent as a sample pad with an indicator function.

Example 9
A sample pad prepared by a conventional method using a circular knitting machine (FRS / L, 21 inch, 20G, manufactured by Fukuhara Seiki Seisakusho Co., Ltd.) as an absorber was excellent as a sample pad with an indicator function.

[Comparative Examples 1-6]
A sample pad was prepared by integrating the absorbent body and the colored layer in the same manner as in Example 1 except that an absorbent body having a basis weight, density, ΔL1, ΔL2, and cellulose mixture ratio adjusted as shown in Table 1 was used. ,evaluated. The results are as shown in Table 1, and were unsuitable as a sample pad with an indicator function. That is, either the indicator function, or temporary water retention or liquid permeability is x, and it cannot be used as a sample pad with an indicator function.

  By using the sample pad for a test kit of the present invention for a test kit, it can have an indicator function of color development with a sufficient amount of liquid absorption. Therefore, the measurer can easily determine whether the amount of liquid absorption is sufficient for measurement.

DESCRIPTION OF SYMBOLS 1 Housing 2 Collecting hole 3 Judgment window 4 Inner sheet 5 Sample pad 6 Reagent containing part (conjugate pad)
7 Judgment display (membrane)
8 Water absorption / drying section (water absorption pad)

Claims (4)

  A test pad sample pad comprising a test kit for an in-vitro diagnostic agent, wherein a colored layer is disposed on the back side of the absorber, and ΔL1 of the absorber is 20 or less and ΔL2 is 30 or more. ^2. The test kit according to claim 1, wherein the absorbent has a cellulose fiber mixture ratio of 50% or more, a basis weight of 75 to 200 g / m ² , and a density of 0.05 to 0.5 g / cm ³ . Sample pad. The sample pad for a test kit according to claim ² , wherein the absorbent has a basis weight of 90 to 150 g / m ² and a density of 0.1 to 0.3 g / cm ³ .   A test kit for an in vitro diagnostic agent in which the sample pad according to claim 1 is arranged.

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