HK1018315B - Chromatography immunoassay device - Google Patents

Description

Device for immunochromatography analysis

Technical Field

The present invention relates to an immunochromatography device using a chromatographic strip. More specifically, the present invention relates to an immunochromatographic assay device in which one or more chromatographic strips are placed on a substrate, each chromatographic strip is sealed between the substrate and a sealing film that completely covers the chromatographic strip, and the sealing film and/or the substrate has a thin film containing a moisture-removing agent and a thin film containing an oxygen-absorbing agent.

Background

An immunochromatographic device using a chromatographic strip is a device for detecting or measuring the presence or amount of a substance to be measured contained in a sample according to an immunological principle, and has at least a sample addition site and a detection site. In some cases, the chromatographic test strip also has ｃA labeling site, and such devices are well known and widely used, for example, in JP-A-61-145459 (the term "JP-A" means an "unexamined published Japanese patent application"), JP-A-1-63865 and JP-W-1-503174 (the term "JP-W" means an "unexamined published Japanese patent application")

"unexamined published Japanese International patent application"), which is incorporated herein by reference.

Each chromatographic strip must be protected by an appropriate means such as packaging in order to prevent deterioration of antibodies and the like in the chromatographic strip due to oxygen, moisture, etc., and to protect the strip itself from contamination or deformation or the like due to contact. Protection by packaging or the like is generally achieved by adhering or placing one or more chromatographic strips to a substrate, placing the formed preform in a protective cartridge, and then sealing the cartridge in a bag. Alternatively, each chromatographic strip may be sealed with a thin membrane, as disclosed in WO 94/24563, which is incorporated herein by reference. When packaged in a bag, the chromatographic strip is sealed with a desiccant so that minimal moisture is absorbed by the chromatographic strip.

However, in the conventional immunochromatographic assay device, each chromatographic strip requires a protective cartridge, a desiccant, and a package in which the chromatographic strip is sealed, and therefore the cost for packaging is large. In a case where a plurality of chromatographic strips are adhered to one substrate, all the chromatographic strips are packed in a single bag together with a necessary amount of a desiccant, and sealed with a water-impermeable packing material. Although this method can reduce the cost required for packaging materials and desiccant, unsealing the pouch using the first chromatographic strip causes the remaining chromatographic strips to be exposed to air, or moisture and oxygen, thereby causing deterioration problems. Special protection and storage measures are therefore required, since the stored chromatographic test strips become unusable if not perfectly protected and stored. The chromatographic test strip used in the incorporated by reference application WO 94/24563 can be isolated from air without the need to provide additional measures to protect the chromatographic test strip from moisture and oxygen.

Summary of The Invention

The present invention solves the above-mentioned problems of the prior art immunochromatographic assay device, which is solved by the structural means and packaging, and therefore provides an immunochromatographic assay device which is easy to use, can be more effectively isolated from moisture and/or oxygen, can be stored for a long time, and can be produced at low cost.

An immunochromatographic assay device has been developed which is easy to use, more effectively protected from the action of moisture and/or oxygen, and is inexpensive to manufacture. In the immunochromatographic assay device of the present invention, one or more chromatographic strips are placed on a substrate, each chromatographic strip is sealed between the substrate and a sealing film completely covering the chromatographic strip, and the sealing film and/or the substrate has a film containing a moisture-removing agent and a film containing an oxygen-absorbing agent.

Accordingly, the gist of the present invention is to provide an immunochromatographic assay device in which (1) one or more chromatographic strips, which are placed at regular intervals on a substrate composed of a sheet, with or without a strip holding member, and have at least a sample addition site and a detection site, (2) a sealing film completely covering the chromatographic strips, with or without a protective sheet, is placed on the chromatographic strips, (3) each chromatographic strip is sealed by closely adhering the sealing film to a portion of the substrate surrounding each chromatographic strip, (4) the adhesion of the sealing film to the substrate is carried out in such a manner that the sealing film at least in the sample addition region can be easily peeled off from the substrate, (5) with respect to the sealing film and the substrate, (i) either the sealing film or the substrate has both a film containing a desiccant and a film containing an oxygen absorbent, (ii) (ii) either the sealing film or the substrate or the film containing a desiccant or the film containing an oxygen-absorbing agent; and the other way is to have both a film containing a desiccant and a film containing an oxygen absorbent, (iv) both the sealing film and the substrate include both a film containing a desiccant and a film containing an oxygen absorbent, (v) both the sealing film and the substrate include the same film, which is either a film containing a desiccant or a film containing an oxygen absorbent, or (iv) either the sealing film or the substrate or a film containing a desiccant or a film containing an oxygen absorbent, and (6) when the sealing film and/or the substrate has a film containing a desiccant, the sealing film and the substrate are water-impermeable at least at a portion where the sealing film is not tightly bonded to the substrate, and when the sealing film and/or the substrate has a film containing an oxygen absorbent, the sealing film and the substrate are oxygen-impermeable at least at a portion where the sealing film is not tightly bonded to the substrate.

The present invention also provides a device for immunochromatography capable of resisting environmental deterioration due to the action of water or oxygen, comprising a sheet-like material capable of maintaining capillary flow, on which a biological reagent capable of reacting with a specific reaction partner under environmental conditions is immobilized, the sheet-like material being packaged between two flat materials sealed together so that the flat materials can be easily and at least partially separated to expose at least a part of the capillary flow sheet-like material, wherein at least one of the two flat materials carries a film containing a drying agent or a film containing an oxygen-absorbing agent or both on its surface facing the capillary flow sheet-like material.

In a preferred immunochromatographic assay device of the present invention which is resistant to environmental deterioration due to the action of water or oxygen, at least one of the flat materials carries at least a desiccant-containing film, and the flat material is water-impermeable at least in the portions other than the portions bonded to each other.

Preferably, the labelled biological reagent capable of reacting with a specific reaction partner under a variety of environmental conditions is deposited on the capillary flow sheet material in such a way that the reagent is capable of moving with a liquid sample moving along the flow sheet material by capillary action.

More preferably, the labeled biological reagent contains a colored substance, the color of which becomes visible if the colored substance accumulates in a sufficient amount as a result of the analysis being performed.

Effects of the invention

The immunochromatographic assay device is easy to use, resistant to the action of moisture and/or oxygen, and low in manufacturing cost. In the immunochromatographic assay device of the present invention, one or more chromatographic strips are bonded to a substrate formed of a single sheet, and each chromatographic strip is sealed by closely bonding a portion of the substrate surrounding each chromatographic strip to a sealing film disposed on the chromatographic strip; and the sealing tape and/or the substrate has a film containing a moisture-removing agent and/or a film containing an oxygen-absorbing agent. Since the chromatographic test strip is isolated from moisture and/or oxygen by the sealing film and the substrate, it can be stored for a longer period of time. Further, even in the case where a plurality of chromatographic strips are bonded to a substrate, when one chromatographic strip is used, the remaining chromatographic strips are not exposed to air, unlike conventional devices of the type currently used. In addition, the chromatographic strip of the present invention can be separated from other strips on the substrate and not exposed to air before and after use. Further, the immunochromatographic assay device of the present invention does not require the packaging labor required for preparing a chromatographic strip as in the prior art. Thus, the test strips described herein can be prepared at low cost.

Detailed Description

In the chromatographic strip, at least a sample addition site and a detection site are disposed on a chromatographic carrier. When a sample solution is added to the sample addition site, the sample solution that may contain the substance to be measured moves through the chromatographic carrier due to capillary action; and a labeling substance previously added to the chromatographic strip at a labeling site provided on the chromatographic strip or together with the sample solution, so that the presence or amount of the substance to be determined in the sample solution can be derived by measuring the presence or amount of the labeling substance thus aggregated, since the progress of the immunoreaction is aggregated in proportion to or in inverse proportion to the amount of the substance to be determined in the sample solution. Various types of chromatographic test strips are known, and all of these known chromatographic test strips including those described later can be used in the present invention. The term "immunochromatographic device" used herein means a chromatographic test strip produced in this manner, which can be used in immunoassay and can be stored and transported.

A typical example of the chromatographic strip is described below. When a labeling site is present, the sample addition site may be located at the same position where the labeling site is present, or at an upstream position of the labeling site (hereinafter, the direction of movement of the sample solution due to capillary action is referred to as "downstream", and the opposite direction is referred to as "upstream"), preferably upstream of the labeling site. When a sample solution containing a substance to be measured is added to a sample addition site, the sample solution moves in a downstream direction along with the substance to be measured through a carrier for chromatography by capillary action. Usually, the substance to be measured is a compound which binds in a specific manner to the capturing substance immobilized on the detection site, or the substance to be measured is a compound which binds in a specific manner to a conjugate which binds specifically to the capturing substance. For example, when the capturing substance is an antigen or the conjugate contains an antigen, the substance to be measured is an antibody; when the capturing substance is an antibody or the conjugate contains an antibody, the substance to be measured is an antigen.

When the sample addition site is located at an upstream position of the marking site (in the case where the marking site is present), the marking site may be disposed adjacent to the sample addition site or at a position separated from the sample addition site. In general, a labeling substance that specifically binds to a substance to be measured or specifically binds to a capture substance that competes with the substance to be measured is disposed in a labeling site.

When the labeling site is not present, a labeling substance may be added to the sample addition site together with the sample solution, and the addition of the labeling substance may be carried out in various ways, for example, after the addition of the sample solution, it may be added to a position other than the binding site of the chromatographic strip.

The label may be a radioisotope, an enzyme or a colored substance such as gold colloid or the like. Such markers are also well known.

Since the labeling substance is disposed so as to move by capillary action of the sample solution, the labeling substance moves in the downstream direction when the sample solution is added to the sample addition site.

The detection site is typically located downstream from the labeling site and at a distance from the labeling site. In the detection site, only the capture substance specifically bound to the substance to be measured or the conjugate or specifically bound to each of the substance to be measured and the labeling substance is immobilized on the chromatographic carrier. Thus, in one embodiment, the substance to be measured (sometimes bound to a labeling substance) that moves by capillary action of the sample solution is bound to a capture substance, or to a conjugate that is bound to a collection substance. The binding of the labeling substance to the thus-bound substance to be measured realizes the aggregation of the labeling substance in the detecting part to reflect the presence or amount of the substance to be measured. In another method, the labeled substance and the substance to be measured, which move by capillary action, bind to the capturing substance or to the conjugate bound to the capturing substance in a competitive manner, and therefore, the aggregation of the labeled substance is achieved in a manner inversely proportional to the amount of the substance to be measured.

There is a case where a certain labeled substance is bound to both the capturing substance (or to the conjugate bound to the capturing substance) and the substance to be measured, but not simultaneously, and in that case, the substance to be measured is bound to the labeled substance first, and the remaining labeled substance not bound to the substance to be measured is bound to the capturing substance. The presence and amount of the substance to be determined can thus be analyzed by measuring the labeled substance accumulated in the detection site.

If necessary, various substances are placed upstream of the detection site. For example, the conjugate is movably positioned. The conjugate is a complex of a compound specifically binding to the substance to be measured or to the labeling substance and a complex with another compound specifically binding to the capturing substance, and the conjugate binds to both the substance to be measured and the capturing substance in a specific manner or to both the labeling substance and the capturing substance in a specific manner. Examples of combinations of compounds specifically bound to capture substances and corresponding capture substances include biotin and avidin (both of which can serve as capture substances), antibodies and their corresponding antigens (both of which are unrelated to the sample to be assayed), and others.

In some cases, one or more additional detection sites may be disposed downstream of the first detection site. In addition, a further extension of the support for spectroscopic analysis may be provided downstream of the detection site, so that the sample solution can be completely drained off, or the support may contain a material for absorbing the sample solution.

The carrier for chromatography is a carrier for a sample addition site, a labeling site and a detection site, and connects these parts in such a manner that a sample solution can move by capillary action. Many materials can be used as a carrier for chromatography, and these materials can also be used as a carrier for chromatography in the present invention. For example, cellulose, nitrocellulose, cellulose acetate and the like are very commonly used as carriers for chromatography.

Therefore, by measuring the presence and amount of the labeled substance accumulated in the detection site, the presence or amount of the substance to be measured in the sample solution can be measured. This can be done, for example, visually.

If desired, the chromatographic strip may be adhered to a strip holder in such a manner that one side of the strip contacts the holder (hereinafter, the side in contact with the strip holder is referred to as the "back side" of the chromatographic strip). The use of the test strip fixing member is mainly to prevent the movement of the sample addition site, the labeling site, and the like. The chromatographic test strip must be adhered to the test strip holding member in such a manner that the capillary action of the sample solution in the chromatographic carrier is not disturbed so that the detection sensitivity of the substance to be measured is not lowered. In some cases, the test strip holder can be used such that a portion of the sample addition site is uncovered.

Further, if necessary, a protective sheet may be adhered to the reverse side of the chromatographic test strip to the side to which the test strip holder is adhered (hereinafter, this side or the reverse side to the side to which the substrate is adhered is referred to as the "front side" of the chromatographic test strip). The protective sheet is mainly used to ensure adhesion between the sample addition site and the labeling site to prevent contamination and other cracks from occurring in the chromatographic test strip when used. At least a part of the protective sheet covering the detection site needs to be transparent, and the sample addition site of the sample addition site does not need to be covered with the protective sheet. The attachment of the chromatographic test strip to the protective sheet must be carried out in such a manner that the capillary action of the sample solution in the chromatographic carrier is not disturbed or the detection sensitivity of the substance to be measured is not lowered.

Polyethylene terephthalate (hereinafter referred to as PET) is most often used as the test strip holder and protective sheet; polypropylene (hereinafter referred to as "PP"), polyvinyl chloride, etc. may also be used.

The chromatographic strip may be adhered to the strip holder or protective sheet or to the substrate by the use of a rubber, acrylic or vinyl ether polymer adhesive, as described below.

One or more chromatographic strips may be placed on the strip substrate with or without a strip holder. The term "disposed on" means that the chromatographic strip is simply placed on the substrate or, in another example, adhered to the strip holder when there is a strip holder or adhered to the substrate when there is no strip holder. The term "adhesive" means that either the entire surface of the chromatographic strip or only a portion thereof is adhered to the base surface. In summary, the adhesion of chromatographic strips is considered effective if it is not easily separated from the strip holder or substrate during the manufacturing process of the strip or when it is used. In some cases, the substrate may be pasted so that it can be easily peeled off from the chromatographic test strip or the test strip holder.

The substrate can function as a test strip holder when the test strip holder is not in use.

When a plurality of chromatographic strips are placed on the substrate, it is desirable from a manufacturing point of view to make the upstream end and the downstream end of each chromatographic strip coincident so that they are parallel. These chromatographic strips are disposed on a substrate and spaced apart from each other.

The substrate is comprised of a single piece and is adhered to the strip holder when present, or to the back of the chromatographic strip.

The chromatographic test strips are sealed by closely adhering a sealing film to be described later to the substrate at the peripheral region of the chromatographic test strips placed on the substrate, i.e., at the spacer region between the chromatographic test strips when a plurality of strips are placed on the substrate.

The sealing film may cover one sheet of the thin film of the entire portion of the chromatographic test strip and be placed on the chromatographic test strip with or without the protective sheet.

If the substrate is to be adhered tightly to the sealing film by heat sealing, the inner face of the substrate (the face of the chromatographic strip) and the inner face of the sealing film (the face of the chromatographic strip) must be heat-sealable, i.e., they must comprise a heat-sealable material. Examples of heat-sealable materials for sealing films and substrates include: a combination of a film having polyethylene (hereinafter referred to as "PE") or PP on the inside thereof and a film having a corresponding hot-melt adhesive on the inside thereof; or a combination of a film having PE on the inside and a film having PP-PE copolymer on the inside.

If the sealing film is bonded to the substrate by paste, the bonding is achieved by an alternative combination of the sealing film and substrate having a rubber, acrylic or vinyl ether polymer adhesive on the inside thereof.

The tight adhesion of the sealing film and the substrate can be achieved in such a manner that the substrate and the sealing film can be easily peeled off at least at the position of the sample addition site when used. In order to achieve easy peeling of the substrate and the sealing film and maintain excellent sealing performance, a peel strength of 1.5 to 2.0kg in the 15 th mm width is desirable.

With respect to the sealing film and the substrate, (i) either the sealing film or the substrate has both a film containing a moisture scavenger and a film containing an oxygen absorbent, (ii) either the sealing film or the substrate has a film containing a moisture scavenger or a film containing an oxygen absorbent; and the substrate has another film; (iii) or the sealing film or the substrate or the film containing a moisture-removing agent or the film containing an oxygen-absorbing agent, and the other of the sealing film and the substrate has both the film containing a moisture-removing agent and the film containing an oxygen-absorbing agent, (iv) both the sealing film and the substrate have both the film containing a moisture-removing agent and the film containing an oxygen-absorbing agent; (v) both the sealing film and the substrate comprise the same film, either a film containing a moisture scavenger or a film containing an oxygen getter; or (vi) either a sealing film or substrate or a film comprising a desiccant or a film comprising an oxygen getter. When the sealing film and/or the substrate has a film containing a moisture-removing agent, the sealing film and the substrate are substantially impermeable to water at least in a portion of the sealing film which is not closely adhered to the substrate, and when the sealing film and/or the substrate has a film containing an oxygen-absorbing agent, the sealing film and the substrate are substantially impermeable to oxygen at least in a portion of the sealing film which is not closely adhered to the substrate.

When the sealing film has a film containing a desiccant, a water-impermeable layer is provided on the outer surface of the sealing film. Further, when the sealing film has a film containing an oxygen absorbent, an oxygen impermeable layer is provided on the outer face of the sealing film. In the same manner, when the substrate has a film containing a moisture absorbent, there is a water impermeable layer on the outside of the substrate, and when the substrate has a film containing an oxygen absorbent, there is an oxygen impermeable layer on the outside of the substrate. In many cases, it is desirable that the outermost face of the sealing film be formed in a manner that allows printing to be performed thereon.

When the sealing film and/or the substrate does not have the film containing a moisture-removing agent and the film containing an oxygen-absorbing agent, the sealing film and/or the substrate may be a single-layer film or a multi-layer film obtained by selectively combining an oxygen-impermeable film, a water-impermeable film, a film suitable for heat sealing, an outermost PET film, and the like.

When both the substrate and the sealing film are free of the oxygen absorbent-containing film, the substrate and the sealing film are not necessarily impermeable to oxygen, and when both the substrate and the sealing film are free of the moisture absorbent-containing film, the substrate and the sealing film are not necessarily impermeable to water. That is, when the chromatographic test strip is not deteriorated by moisture, it is not necessary to use a film containing a desiccant or a water-impermeable sealing film and a substrate; or when the chromatographic strip is not deteriorated by oxygen, it is not necessary to use a film containing an oxygen absorbent or an oxygen-impermeable sealing film and substrate.

The desiccant-containing film may be prepared by mixing a thermoplastic high molecular weight resin, preferably a polyolefin, more preferably selected from the group consisting of low density polyethylene, low linear density polyethylene, ethylene-ethoxy copolymers, ethylene acrylic acid copolymers, ethylene methacrylic acid copolymers, ethylene acrylic acid ester copolymers, and ionomers based on acrylic acid and methacrylic acid copolymers, with an appropriate amount of calcium chloride, silica gel, molecular sieves, silica, alumina, zeolite magnesium sulfate, calcium sulfate, and the like as a dehydrating agent. Examples of the Film containing a Moisture-removing agent include "Moisture Guard" (manufactured by Toyo Seikan Co., Ltd.) and "Histone Dry Film" (manufactured by Marutani Kakoki Co., Ltd.) disclosed in Japanese patent laid-open No. 08-026348(26348/96), which are incorporated herein by reference. A particularly preferred desiccant containing film is 110 microns thick and consists of about 10 microns of Low Density Pe (LDPE), about 90 microns of a dehydrated layer containing a variable amount of a high molecular weight resin such as LDPE and a dehydrating agent such as zeolite, molecular sieve, etc., and about 10 microns of LDPE. Suitable desiccant-containing films are preferably film layers having a desiccant content of about 0.1 to 50% by weight, preferably 10 to 50% by weight. A total dehydrating agent content of about 8 to 50g/m is particularly preferred. It is preferred to use a dehydrating agent having an average particle size of about 5 to 70 μm to prepare a film containing the dehydrating agent.

The oxygen getter containing film can be prepared by mixing a thermoplastic high molecular weight resin with appropriate amounts of active ionic oxide, pyrogallol and similar oxygen getters. An example of the oxygen absorbent-containing film is "Oxy Guard" (manufactured by Toyo Seikan corporation).

In some cases, the sealing film is a film containing both a moisture scavenger and an oxygen getter. This type of sealing film is referred to herein as a desiccant-containing film or an oxygen-absorbent-containing film. Also, the substrate may be a film containing both a moisture scavenger and an oxygen getter. This type of substrate may be referred to herein as a desiccant containing substrate or an oxygen getter containing substrate.

Illustrative examples of substantially water impermeable substrates include: 300 micron or thicker PE; PP of 300 microns or more; a multilayer film composed of [ PE or PP ] of 300 μm or more and polyvinylidene chloride (hereinafter referred to as "PVDC") of about 15 μm from the inner face; and a multilayer film consisting of about 70 microns [ PE or PP ], about 125 microns PET and about 15 microns PVDC from the inner face. Illustrative examples of substrates that are substantially impermeable to water and contain desiccant-containing films include: 300 micron "Moisture Guard" and its multilayer film consisting of about 110 micron "Moisture Guard" from the inside, about 125 micron PET and about 15 micron PVDC. Illustrative examples of substantially oxygen impermeable substrates include: which is a multilayer film composed of [ PE or PP ] of about 150 μm or more, a polyvinyl alcohol soap of about 15 μm, and [ PE or PP ] of 150 μm or more from the inner face. The above examples are all transparent.

Illustrative examples of substrates that are substantially impermeable to water and oxygen include: which is a multilayer film composed of [ PE or PP ] of 150 μm or more, PVDC of about 30 μm, and [ PE or PP ] of 50 μm or more from the inner face. Illustrative examples of substrates that are substantially impermeable to water and oxygen and opaque include: a multilayer film composed of [ PE or PP ] 200 μm or more, an aluminum foil (hereinafter referred to as "Al") of about 7 μm, and PET of about 15 μm from the inner face; a multilayer film consisting of, from the inner face, a multilayer film of [ PE or PP ] 70 microns, PET of about 125 microns, Al of about 7 microns and PET of 12 microns; it consists of a multilayer film, starting from the inner face, of about 70 microns [ PE or PP ], about 125 microns of polystyrene, about 7 microns of Al and about 12 microns of PET.

A preferred substrate consists of a layer of about 30 microns from the inside to facilitate removal of the sealing film, consisting of a mixed layer of PE and PP, white PET of about 188 microns (for color contrast), Al of about 7 microns (as an oxygen and moisture barrier) and PET of 12 microns. A particularly preferred substrate consists of a layer of about 30 micrometers from the inside, which facilitates the removal of the sealing film, consisting of a mixed layer of PE and PP, about 50 micrometers white PET, about 7 micrometers Al and about 188 micrometers PET.

A substrate which is substantially impermeable to water and oxygen and which contains a film comprising a Moisture scavenger and/or an oxygen getter may be obtained by replacing the inner film of the above-described multilayer film which is substantially impermeable to water and oxygen with a "motion Guard" of 110-.

If desired, a paste of a rubber, propylene ether or vinyl ether polymer may be applied to both sides, particularly the inner side, of the substrate. In that case, a releasable paper or a releasable film is stacked on the surface coated with the paste until use. Paper, PET, PP, or the like may be used as the releasable paper or the releasable film, and there is no particular limitation thereto.

Illustrative examples of the sealing film which is water-impermeable include a multilayer film thereof composed of about 70 μm of [ PE or PP ] and about 12 μm of PET from the inner face. Those sealing films that are substantially impermeable to oxygen include multilayer films from the inside of which are composed of about 70 microns of [ PE or PP ], about 15 microns of polyvinyl alcohol saponificate, about 12 microns of PP and about 12 microns of PET. The substantially water and oxygen impermeable sealing membrane comprises a multilayer film of about 70 microns [ PE or PP ], about 30 microns PVDC and about 12 microns PET from the inside. All of the above examples are transparent.

Illustrative examples of the sealing film which is substantially impermeable to water and contains a desiccant-containing film include a multilayer film composed of "Moisture Guard" of 110 μm and PET (transparent) of about 12 μm from the inner face thereof; and particularly preferred is a multilayer film which consists of, from the inner face, "Moisture Guard" of about 110 microns, Al of about 7 microns and PET (opaque) of about 12 microns. An illustrative example of a sealing film which is substantially impermeable to oxygen and contains an oxygen getter-containing film is a multilayer film which consists of, from the inside, "Oxy Guard" of 110 microns, Al of 7 microns and PET (opaque) of 12 microns. An illustrative example of the sealing film containing a desiccant-containing film and an oxygen-absorbent containing film which is substantially impermeable to water and oxygen is a multilayer film composed of, from the inner face, "Moisture Guard" of 110 micrometers, "OxyGuard" of 110 micrometers, Al of about 7 micrometers, and PET (opaque) of 12 micrometers.

By bonding the component films together using a suitable adhesive, or by laminating portions of the component films using coextrusion; the multilayer film can be made by bonding the remaining constituent materials together, if desired, using a suitable adhesive.

By first preparing the above chromatographic strip and, if necessary, using the strip holder and/or the protective sheet in the above manner; alternatively, the immunochromatographic assay device can be manufactured by preparing a chromatographic strip, simultaneously bonding the sample addition site and the like, and sealing the chromatographic strip by tightly bonding the substrate to a sealing film.

The immunochromatographic assay device of the present invention is used as follows. Only a single chromatographic strip to be used is cut out together with the substrate. The sealing film is peeled off at least a portion of the film covering the sample addition site, and the sample solution is added to the exposed sample addition site. In the case of a shaped sealing film, it may be necessary to peel off the entire portion of the sealing film covering the chromatographic test strip. When a plurality of chromatographic strips are placed on a substrate and one chromatographic strip is used while it is not first cut out, it is generally cut out after its use. In some cases, the device can be used by detaching the substrate from the test strip holder.

The invention is further described with reference to the accompanying drawings. FIG. 1 is a schematic view of an example of the immunochromatographic assay device of the present invention. In the drawings, a is a plan view, b is a sectional view, and c is another sectional view. Fig. 2 is a schematic diagram showing an example of a chromatographic strip. FIG. 3 is a schematic view of another example of the immunochromatographic assay device of the present invention. In these drawings, 1 represents a chromatographic strip, 2 represents a substrate, 3 represents a sealing film, 4 represents a chromatographic carrier, 5 represents a sample addition site, 6 represents a labeling site, 7 represents a detection site, 8 represents a strip fixing member, 9 represents a protective sheet, 10 represents a punched cut line, and 11 (hatched portion) represents a tightly bonded portion of the substrate and the sealing film.

The chromatographic strip 1 is placed on the substrate 2 and sealed from air together with the desiccant-and/or oxygen absorbent-containing film by closely adhering the sealing film 3 to the area 11 around the chromatographic strip on the substrate 2 (fig. 1).

When the comb-shaped substrate shown in FIG. 3 is used, the sample addition site in each chromatographic strip is completely isolated, so that there is no risk that a sample solution flows into an adjacent chromatographic strip due to an erroneous operation when a sample is added.

A chromatographic test strip 1 (FIG. 2) is constituted by arranging a sample addition site 5, a labeling site 6 and a detection site 7 on a chromatographic carrier 4. The chromatographic strip is fixed and protected by a strip fixing member 8 and a protective sheet 9, as necessary.

The punch line 10 may also be provided when necessary so that when a plurality of chromatographic strips are placed on the base surface, the cutting of a single chromatographic strip from the immunochromatographic device can be easily achieved. The punch cutting line 10 may be used in such a manner that a single chromatographic strip may be cut out, or several chromatographic strips may be cut out at the same time.

Brief Description of Drawings

FIG. 1 is a schematic view showing an example of the immunochromatographic device of the present invention, in which a is a plan view, b is a side view, and c is a front view.

Fig. 2 is a schematic diagram showing an example of a chromatographic strip.

FIG. 3 is a schematic view showing another example of the immunochromatographic assay device of the present invention.

Description of the reference symbols

1 chromatographic test strip

2 substrate

3 sealing film

4 chromatographic carrier

5 sample addition site

6 marking site

7 detection site

8 test strip fixing part

9 protective sheet

10 punch a hole cutting line

11 tight adhesion part of substrate and sealing film

Examples of the invention

EXAMPLE 1 Properties of sealing film and substrate combinations

A combination of a sealing film and a substrate as shown in table 1 was produced. The multilayer film is produced by bonding the individual single-layer films together with an adhesive.

TABLE 1

Sample number	Sealing film	Substrate
			1234567 (control)	MG/Al/PET12MG/PVDC/PET12MG/Al/PET12MG/OG/Al/PET12OG/Al/PET12MGPP70/Al/PET12	PP70/PET125/Al/PET12PP300MG/PET125/Al/PET12PP70/PET125/Al/PET12MG/PET125/Al/PET12PP300PP70/PET125/Al/PET12

MG: 110 μm "Moisture Guard" (manufactured by Toyo Seikan Co., Ltd.)

OG: 110 μm "Oxy Guard" (manufactured by Toyo Seikan Co., Ltd.)

Al: 7 micron Al

PET₁₂: 12 micron PET

PET₁₂₅: 125 micrometer PET

PP₇₀: 70 micron PP

PP₃₀₀: 300 micron PP

PVDC: 12 micron PVDC

A Dewetting Performance test 1

The sealing films of samples 1, 2, 3, 4 and 7, the substrates of samples 3 and 5, and commercially available encapsulated granular silica gel were stored at room temperature (23 ℃ C., humidity 40%) or in an incubator (40 ℃ C.) for 3 days in the respective amounts shown in Table 2. Then, the weight of each sample was measured, and the weight gain from the initial weight was taken as the weight of absorbed moisture. The results are shown in Table 2.

From these results, it is apparent that those films containing a desiccant have a high dehumidifying ability.

TABLE 2

Absorbed moisture (mg)

23℃ 40℃

Sample size

Seal film 300cm of sample 1² 84.2 79.7

Sealing film 300cm of sample 2² 84.0 79.5

Seal film 300cm of sample 3² 83.5 78.9

Seal film 300cm of sample 4² 83.7 78.6

Substrate 300cm of sample 3² 84.9 80.3

Substrate 300cm of sample 5² 84.1 79.9

Encapsulated granular silica gel (control) 5g 892288

Sealing film (control) of sample 7 by 30cm² 0.1 -0.1

The above study was repeated to determine the absorption capacity of silica gel (5g encapsulation) and the amount of dehydrating agent contained (0.75 g/300 cm)²(sealing film A) or containing 1.50 dehydrating agent/300 cm²(sealing film B) in comparison with the sealing film of sample 1 or 3. Storage conditions were 24 ℃ at 50% relative humidity, 40 ℃ at 20% relative humidity, or 2-8 ℃ at 90% relative humidity for 6 days, and samples were also stored at 2-8 ℃ at 90% relative humidity for 19 days. The results were calculated as above (mg of absorbed water) and as% (g of absorbed water/g of desiccant)% (Table 3). From these results, it can be seen that each film had high moisture absorption and removal capabilities. Further, film B, which contains twice as much dehydrating agent as film a, has about twice as much ability to absorb moisture as film a.

TABLE 3

Storage conditions the amount of water absorbed at the storage time

Sample (temperature/relative (days) (mg) (g/g%)

Humidity)

Sealing film A40 deg.C/20% 612917.26

Sealing film A24 deg.C/50% 614118.78

Sealing film A2-8 deg.C/90% 67610.17

Sealing film A2-8 deg.C/90% 1914419.13

Sealing film B40 deg.C/20% 626817.84

Sealing film B24 deg.C/50% 629219.45

Sealing film B2-8 deg.C/90% 61218.06

Sealing film B2-8 deg.C/90% 1927718.47

Silica gel 40 deg.C/20% 64959.9

Silica gel 24 deg.C/50% 6147229.44

Silica gel 2-8 deg.C/90% 6185737.15

Silica gel 2-8 deg.C/90% 19193738.74

B Dewetting Performance test 2

Each bag (inner surface area 600 cm) was made from the sealing films of samples 1, 2, 3, 4 and 6 and the substrates of samples 3 and 5 (see Table 1)²) And three sides of the bag are heat sealed. A strip of wetness indicating paper manufactured by Humidial corporation, USA, was then placed in each bag, and the remaining side was heat sealed. Similar bags (inner surface area 600 cm) were made with the sealing film of sample 7²). The humidity indicator strip described above and 2g of encapsulated granular silica gel were placed in a bag and the remaining side was heat-sealed. As a control, a similar bag (inner surface area 600 cm) was made of the sealing film of sample 7²) The humidity indicator strip is placed in a bag and the remaining side is heat sealed. The bags thus made were maintained at room temperature for 3 days and then opened, and the humidity was immediately read using a humidity indicator paper strip when the bags were opened.

Humidity was indicated to be 45% in the control bag and 15% or less in all other bags. The minimum moisture measurable with such a moisture indicating paper strip is 15%.

C Oxygen uptake Performance test

Bags (inner surface area 600 cm) were made from the sealing films of samples 4 and 5²) (see table 1), and heat sealing the four sides of each bag. A piece of natural rubber 1X 1cm in size was adhered to the surface of the bag with an adhesive. The air in the bag was completely evacuated through the natural rubber sheet using a syringe, and then 20ml of air was precisely injected. After 3 days at room temperature, a portion of the air in the bag was taken out through the natural rubber sheet to measure the oxygen concentration using a gas chromatograph equipped with a molecular sieve packed column.

No oxygen was detected in any of the tested bags. The limit value for the detection of the oxygen concentration in such an analytical system is 0.01%. It is apparent from the test results that the multilayer film having the oxygen absorbent-containing film has oxygen absorbing ability.

Based on the above results, it can be expected that the immunochromatographic assay device produced by the method described in example 2 below using the sealing film and the substrate of sample 1, 2, 3, 4, 5 or 6 will have a high dehumidifying ability. It is expected that the immunochromatographic device produced using the sealing film and the substrate of sample 4 or 5 also has high oxygen-absorbing ability.

EXAMPLE 2 stability of devices for immunochromatography analysis

Fabrication of A device

A labeled substance consisting of an antibody against human hemoglobin labeled with selenium colloid was prepared as follows. First, 1mM sodium L-ascorbate and 32mM selenium oxide were stirred at about 4 ℃ for 15 minutes, and then at about 42 ℃ for about 70 hours. The selenium colloid thus obtained was diluted with 10mM of pH 7.0 binary-ternary buffer to reach an optical density of 15 at 550 nm. The resulting dilution was mixed with murine monoclonal anti-human hemoglobin antibody (0.02%) and stirred at room temperature for 1 hour. The selenium colloid-labeled anti-human hemoglobin antibody thus obtained was washed with 10mM of ternary HCl buffer solution having pH 7.2 and used as a labeling substance.

The labeling sites were prepared as follows: the labeling substance was added to 10mM of a ternary HCl buffer solution containing 1% casein at pH 7.2, and the optical density at 550nm was adjusted to 1.0, so as to obtain a suspension of the labeling substance. A glass fiber membrane (Lypore 9524, manufactured by LYDALL, USA) was immersed in the obtained suspension liquid and sufficiently soaked, and then the glass fiber membrane was dried to be used as a marking site.

The detection site was prepared as follows: a murine monoclonal anti-human hemoglobin antibody, which binds to human hemoglobin at a different binding site than the above anti-human hemoglobin antibody, was added to 30mM of a pH 7.4 ternary HCl buffer containing 150mM sodium chloride at a final concentration of 2 mg/ml. Further, as a carrier for chromatography, a rectangular nitrocellulose membrane sheet (manufactured by Schleicher & Schuell, usa) having a size of 0.4 × 4.5cm and a pore diameter of 5 μm was bonded to a rectangular test strip fixing member (PE PET 100 PE LR 007A, manufactured by linetech, inc.) having a size of 0.4 × 6.0cm and a thickness of 100 μm in such a manner that the downstream end portions of the two sheets were aligned with each other when the long side was arranged in the longitudinal direction. The solution mixed with the antibody (anti-human hemoglobin antibody) was added dropwise to the nitrocellulose membrane sheet adhered to the test strip holder, forming a line at about 1cm from the upstream end of the membrane sheet. The antibody was sufficiently dried to fix the anti-human hemoglobin antibody to nitrocellulose.

Chromatographic strips were prepared as follows: the above-mentioned labeled portion was cut into a 0.4X 0.4cm square piece and adhered to the upstream side of the test strip holder containing the detection portion of the nitrocellulose membrane to which anti-human hemoglobin was fixed in such a manner that it slightly touched the nitrocellulose membrane. As the sample addition site, a nonwoven fabric (Sontara 8801, manufactured by dupont) cut to a size of 0.4 × 1.3cm was adhered to the upstream side of the test strip fixing member of the labeling site in such a manner as to slightly touch the labeling site. A rectangular protective film (PET25 PE LR 007A, manufactured by Lintech Co.) having a size of 0.4X 5.1cm was further bonded thereto in such a manner that the upper end of the protective film was aligned with the upper end of the nitrocellulose membrane sheet when the long sides were arranged in the longitudinal direction, thereby obtaining the chromatographic test strip.

The chromatographic strip was adhered to the substrate as follows: the back surface of the test strip holder of each of the total 10 chromatographic test strips was adhered in parallel at 1.8cm intervals to the substrate of sample 1 or 7 (see fig. 1) by uniformly arranging their upper ends.

The sealing film was tightly adhered to the substrate by heat-sealing in the following manner: the substrate to which the chromatographic strips had been adhered was divided into two equal parts, one part of which was heat-sealed to the sealing film of sample 1 in such a manner that a 0.25cm peripheral region around each chromatographic strip was not heat-sealed. Sealing temperature of 120 deg.C, sealing time of 1.5 s and sealing pressure of 3.0kg/cm². The heat seal is subdivided into two portions, one of which is die cut to form a punch cut as shown in FIG. 1. This can be used as device a. The remaining part is made into a device B with a chromatographic strip using another cutting device.

As a control, the remaining portion of the substrate having 5 test strips for chromatography adhered thereto was placed in a bag (size of 25 × 15cm) obtained by heat-sealing three sides of sample 7 together with 5g of commercially available packaged granular silicone rubber, and the bag thus formed was heat-sealed. It was used as device C.

As a control, the substrate of sample 6 to which the chromatographic strip had been adhered was heat-sealed with the sealing film of sample 7 in the same manner as described above. It was used as device D.

B Storage under harsh conditions

The prepared devices A, B, C and D were held at 25 ℃ and 60% relative humidity for 1 day and then at 40 ℃ and 70% relative humidity for 28 days. After storage of devices A, B, C and D under such harsh conditions, at 25 ℃ for 2 hours, then devices A, B and D remained so, while device C was held at 25 ℃ and 60% relative humidity for additional 24, 48, and 96 hours after opening while exposing the devices to outdoor air.

Sample solutions were prepared by dissolving 0, 5, 10, 25, 50, 100, 200, or 500ng/ml of human hemoglobin (manufactured by Sigma company, usa), 0.1% of bovine serum albumin (manufactured by Seikagaku Kogyo company), 0.9% of sodium chloride, and 0.1% of sodium azide in 0.1M of ternary HCl buffer solution having pH 7.6. To the chromatographic strip sample addition sites of each of the devices A, B, C and D, 25. mu.l of the prepared sample solution was added for 24, 48, and 96 hours before, just after, or after storage of the devices under severe conditions. The result is judged by reading the original "red" of the selenium colloid, and if the sample is detected with the naked eye 7 minutes after the addition of the sample solution, the result is obtained if the test strip is positive at the detection site. The sensitivity is based on the minimum hemoglobin concentration at which "redness" can be observed with the naked eye. The results are shown in Table 4.

TABLE 4

Before/after storage under severe conditions

Just before the device 24 hours later and after 48 hours later and after 96 hours later

A 25ng/ml 25ng/ml 25ng/ml 25ng/ml 25ng/ml

B 25ng/ml 25ng/ml 25ng/ml 25ng/ml 25ng/ml

C 25ng/ml 25ng/ml 25ng/ml 50ng/ml 100ng/ml

D 25ng/ml 200ng/ml 200ng/ml 500ng/ml 500ng/ml

As is apparent from table 4, the chromatographic strips of devices A, B and C after storage just under harsh conditions showed the same sensitivity as the chromatographic strips before storage under harsh conditions, and stability during storage under harsh conditions was good. When the storage time reached 24 hours, 48 hours, and then 96 hours under severe conditions, the sensitivity of the devices a and B was unchanged, but the sensitivity of the device C gradually decreased. This indicates that the stability of the unsealed device C is poor. Tests under severe conditions showed that the stability of device D, which contained neither desiccant nor desiccant films, was significantly reduced.

As can be appreciated from this test, conventional products cannot be stored at room temperature after certain chromatographic strips have been used and therefore need to be stored in a refrigerated compartment. Devices made in a conventional manner cannot be operated quickly, for example when emergency testing is required after storage in a cold room, because the devices first need to be warmed to room temperature in order to perform the profiling. However, device a may be emergency compliant, as it can be stored at room temperature. In addition, it can be used reliably because the stability of the chromatographic strip is assured until the sealing film is peeled off. The use of the device a requires no effort, since the sealing film can be easily peeled off.

With respect to product cost, the prior art products require packaging and sealing of the finished device together with desiccant in a substantially moisture-tight or the like bag, while device a does not require such handling so that the product cost can be greatly reduced, compensating for the slight increase in substrate and sealing film costs. The labor required to make device a and the costs associated therewith should also be lower than those of existing products.

Stability of C one month

In the manner described in example 2.A. abovePreparing chromatographic strips for detecting human hemoglobin, and packing 13 strips in aluminum bags (A) without drying; with a coating of 110 micron MG (defined by 10 micron PE/PS (PS is defined herein as polystyrene), 90 micron coating of 11.9g/m²And a desiccant layer of 10 micron PE/PS composition)/15 micron Al/12 micromole PET 67.8cm²Sealing the film package (B); from 678.6cm²The same sealed film package of (C); or packed in an aluminum bag of a conventional desiccant consisting of 1.3g of silica gel (D). All strips were exposed overnight at 25 ℃ and 65% relative humidity before packaging and heat sealing. The silica gel and sealing film were exposed to 25c and 65% relative humidity for 6 hours prior to use.

After the test bars were heat sealed under the packaging conditions described above, they were stored in an incubator at 25 ℃ and tested after 16 and 29 days (25 ℃ storage), or stored in an incubator at 25 ℃ for one day and then moved to an incubator at 37 ℃ and tested after 15 and 28 days after moving to an incubator at 37 ℃ (37 ℃ storage).

The test was performed as in B using a sample containing 0 (negative control), 10, 25, 50, 100 or 500ng/ml of human hemoglobin. The results were read 7 minutes after the addition of the sample and are listed in table 5 as the minimum hemoglobin concentration at which the signal can be observed by eye.

TABLE 5

Conditions of packaging	Test sensitivity (ng/ml)
					Storage at 25 deg.C		Storage at 37 deg.C
	16 days	29 days	16 days	29 days
					A (no desiccant) B (1X seal film) C (10X seal film) D (silica gel)	25252525	50252525	100252525	500252525

The packaged bars without any desiccant showed low sensitivity and therefore poor stability after one month storage at 25 ℃ or 37 ℃. No reduction in test sensitivity was seen with either storage condition when the test strip package was packed with desiccant. The test strip packaged with the desiccant-containing sealing film maintained the same performance as the test strip packaged with silica gel, as well as the same performance as the sealing film when 10 times more sealing film was used, as 1 time more sealing film was used. Therefore, the desiccant containing sealing film maintains test sensitivity and has good stability up to one month under various storage conditions.

EXAMPLE 3 device for Human Immunodeficiency Virus (HIV) immunochromatography Stability of (2)

A chromatographic strip is prepared in a manner similar to that described in example 2A above, except that there are appropriate modifications to enable detection of HIV antibodies, for example, a polyclonal or monoclonal antibody whose labeling site is a commercially available heavy and/or light chain of anti-human IgG, and a detection agent which is an HIV antigen is used. 22 bars are packed with 5g of silica gel as a packingAn aluminum bag of desiccant (a); packed in an aluminum bag (B) containing 2.2g of silica gel as a desiccant; putting the mixture into an aluminum bag without a drying agent (C); using a substrate consisting of 12 micron PET, 7 micron A1, 188 micron PET, 12 micron PET and a peelable layer consisting of a blend of PE, and using a pressure sensitive adhesive containing either 25g/m²(D) Or 50g/m²(E) The desiccant of (1) or (3) (table 1) was placed in the bag after the sealing film was covered. Each test strip, silica gel and sealing film used were exposed to 27 ℃ and 65% relative humidity for 6 hours prior to use. The 5-state packaged bars were then heat sealed.

After heat-sealing the test strips in the above-described packaging conditions, they were stored in an incubator at 25 ℃ for one day and then transferred to an incubator at 30 ℃, an incubator at 45 ℃ or a controlled incubator at 45 ℃ having a relative humidity of 65%. The strips were removed for testing after storage for 0.5, 1, 3 and 6 months.

Using normal human serum/plasma as a negative control, human serum/plasma from individuals infected with HIV-1 and HIV-2 as a positive sample containing HIV-1 or HIV-2 antibodies, the test was repeated as described in example 2, B above. Double serial dilutions made from HIV-1 and HIV-2 samples were prepared, along with 5 for HIV-1 ranging from 211-2¹⁵For HIV-2 is 2¹⁰-2¹¹Double dilutions of (a) were tested. The results were read 15 minutes after sample addition and the highest HIV sample dilution at which a signal could be observed visually is listed in tables 6, 7 and 8. All negative control samples gave negative results for all strips in all packaging and storage conditions.

TABLE 6

Sensitivity of the assay after storage at 30 ℃ (2)xDilution)
											HIV-1						HIV-2
Time (humidity):	0	0.5	1	3	6	0	0.5	1	3	6
											package (I)ABCDE	1313131313	13131313/1413	1313/14121313	13NDND1313	13/14NDND13/1414	1212121212	1212121212	1212111212	12NDND1212	12NDND1212

(ND is not found)

TABLE 7

Sensitivity was tested after storage at 45 ℃ (2)xDilution)
											HIV-1						HIV-2
Time (humidity): 0		0.5	1	3	6	0	0.5	1	3	6
											Package (I)ABCDE	1313131313	1313＜111313	1313＜111313	13NDND1313	13NDND1313	1212121212	1212＜101212	1211＜101212	12NDND1212	12NDND1212

(ND is not measured)

TABLE 8

Test sensitivity after storage at 45 ℃/65% relative temperature (2)xDilution)
											HIV-1						HIV-2
Time (humidity): 0		0.5	1	3	6	0	0.5	1	3	6
											Package (I)ABCDE	1313ND1313	1313ND1313	1313ND1313	13NDND1313	13NDND1313	1212ND1212	1212ND1212	1212ND1212	12NDND1212	12NDND1212

(ND is not found)

Chromatographic test strips (C) without desiccant packaging showed the worst performance under all test conditions, losing sensitivity over storage time. The packaged bars containing higher amounts of silica gel desiccant (5g) or a sealed membrane containing desiccant retained performance for 6 months under all test conditions. Both amounts of desiccant used in the sealing membrane are equally effective. Therefore, the desiccant-containing sealing film can maintain the test sensitivity of the device for chromatography stored therein, and still exhibit good performance and stability in a state of long-term storage.

While the invention has been described in terms of each embodiment, certain modifications can be made by one skilled in the art without departing from the spirit and scope of the invention as described in the specification and claims.

Claims (8)

1. An immunochromatographic assay device, wherein:

(1) one or more chromatographic strips having at least a sample addition site and a detection site, each of which is spaced apart from each other and disposed on a substrate comprising a flat sheet with or without a strip fixing member disposed therebetween;

(2) a sealing film is placed on the chromatographic test strips to cover all the chromatographic test strips with or without a protective sheet interposed therebetween;

(3) the substrate and the sealing film are bonded together at a portion surrounding each chromatographic strip to seal each chromatographic strip;

(4) the adhesion between the sealing film and the substrate is such that the sealing film can be easily peeled off from the substrate at least at the sample addition site;

(5) (ii) one of the sealing film and the substrate comprises one of a desiccant-containing film and an oxygen-absorbent-containing film, and the substrate comprises the other of the desiccant-containing film and the oxygen-absorbent-containing film, (iii) one of the sealing film and the substrate comprises one of a desiccant-containing film and an oxygen-absorbent-containing film, and the other of the sealing film and the substrate comprises both of a desiccant-containing film and an oxygen-absorbent-containing film, or (iv) both of the sealing film and the substrate comprise one or both of a desiccant-containing film and an oxygen-absorbent-containing film, and

(6) when the sealing film and/or the substrate includes a desiccant-containing film, the sealing film and the substrate are water-impermeable at least at a portion other than the bonding portion; when the sealing film and/or the substrate comprises a film containing an oxygen absorbent, the sealing film and the substrate are impermeable to oxygen at least in a portion other than the bonding portion.

2. The immunochromatographic assay device according to claim 1, wherein the chromatographic strip further has a labeling site.

3. The immunochromatographic assay device according to claim 1 or 2, wherein the sealing film is a multilayer film comprising a metal film.

4. The immunochromatographic assay device according to claim 1, wherein the substrate is a multilayer film comprising a metal film.

5. The immunochromatographic assay device according to claim 3, wherein the metal film is an aluminum foil.

6. The immunochromatographic assay device according to claim 4, wherein the metal film is an aluminum foil.

7. The immunochromatographic assay device of claim 1, in which 5 to 12 strips for chromatography are placed on a substrate.

8. The immunochromatographic assay device according to claim 1, wherein the sealing film and the substrate are bonded by heat sealing.