Culture sheet

Abstract

To provide a culture sheet that prevents a culture medium layer from being contaminated by microorganisms or foreign substances other than a specimen.SOLUTION: A culture sheet includes a base material, a culture medium layer, and a cover member. The culture sheet includes a culture space, which is formed such that it is surrounded by the base material and the cover member and in which the culture medium layer is disposed, and a supply hole configured to deliver a test liquid to the culture space.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a culture sheet used for culturing microorganisms. [Background technology]

[0002] It is known to use a culture sheet having a medium layer provided on a base sheet in order to easily perform microbial testing, etc. The culture sheet is provided with a cover sheet that covers the medium layer from the viewpoint of preventing the medium layer from being contaminated with microorganisms other than the specimen or foreign matter during culture (for example, Patent Documents 1 and 2). When culturing using such a culture sheet, the cover sheet is opened to expose the medium layer, the exposed medium layer is inoculated with a test liquid, and then the cover sheet is closed to cover the medium layer and culture is performed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2009-153501 A [Patent Document 2] Patent Publication No. 2022-29737 Summary of the Invention [Problem to be solved by the invention]

[0004] When the cover sheet is opened to expose the medium layer in inoculation of the test liquid into the medium layer, microorganisms or foreign matter attached to the examiner's gloves, etc. may fall onto the medium layer, causing contamination of the medium layer. If cultivation is performed on a culture sheet containing a contaminated medium layer, microorganisms other than the target specimen may be cultivated, which may cause erroneous judgment of the cultivation results.

[0005] An object of the present invention is to provide a culture sheet that can prevent the culture medium layer from being contaminated by microorganisms or foreign matter other than the specimen. [Means for solving the problem]

[0006] [1] A culture sheet having a substrate, a medium layer, and a cover member, A culture space formed so as to be surrounded by the base material and the cover member, and in which the culture medium layer is disposed; A culture sheet having a supply hole for supplying a test liquid to the culture space. [2] The substrate has a recess on a first surface, the cover member is provided on the first surface so as to cover the recess, The culture space is formed by the recess and the cover member, The culture sheet according to [1], wherein the culture medium layer is provided in the recess. [3] The culture sheet according to [2], wherein the base material has a convex shape corresponding to the shape of the concave portion on a second surface opposite to the first surface. [4] The culture sheet according to any one of [1] to [3], wherein the supply hole is provided in the cover member. [5] The culture sheet described in [4], wherein the supply hole is provided in a position of the cover member that does not face the culture medium layer in a planar view. [6] The culture sheet according to any one of [1] to [5], wherein the base material and the cover member are peelably laminated so that the medium layer is exposed. Effect of the Invention

[0007] According to the culture sheet of the present invention, it is possible to prevent the medium layer from being contaminated by microorganisms or foreign matter other than the specimen. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view showing a schematic diagram of a culture sheet according to one embodiment of the present invention. [Diagram 2] 2 is a cross-sectional view that illustrates a cross section taken along line II' in FIG. 1. [Diagram 3] FIG. 11 is a cross-sectional view showing a schematic diagram of a culture sheet according to another embodiment of the present invention. [Figure 4] FIG. 11 is a cross-sectional view showing a schematic diagram of a culture sheet according to another embodiment of the present invention. [Diagram 5] FIG. 11 is a cross-sectional view showing a schematic diagram of a culture sheet according to another embodiment of the present invention. [Figure 6] FIG. 11 is a cross-sectional view showing a schematic diagram of a culture sheet according to another embodiment of the present invention. [Figure 7] FIG. 11 is a perspective view showing a schematic diagram of a culture sheet according to another embodiment of the present invention. [Figure 8] FIG. 11 is a cross-sectional view showing a schematic diagram of a culture sheet according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The culture sheet described in the embodiment of the present invention has a substrate, a culture medium layer, and a cover member. The culture sheet is formed so as to be surrounded by the substrate and the cover member, and has a culture space in which the culture medium layer is placed. The culture sheet further has a supply hole for supplying a test liquid to the culture space. The test liquid usually contains a specimen and a liquid (e.g., water).

[0010] The culture medium layer of the culture sheet is the region in which the specimen, which is the microorganism to be cultured, is cultured. In the culture sheet, culture is carried out by inoculating the test liquid into the culture medium layer. In the culture sheet, the culture medium layer is disposed in a culture space surrounded by a base material and a cover member. Therefore, even before the culture sheet is used, the culture medium layer is less likely to be contaminated by microorganisms or foreign matter other than the specimen (hereinafter also referred to as "microorganisms other than the specimen, etc.").

[0011] On the other hand, when the culture sheet is in use, the test liquid is supplied to the culture space from the supply hole provided in the culture sheet, so that the test liquid is inoculated into the medium layer arranged in the culture space, and the specimen can be cultured in the medium layer. This makes it possible to keep the medium layer from being easily contaminated before and during use of the culture sheet, and is expected to reduce erroneous determination of the culture results using the culture sheet.

[0012] In the culture sheet, the medium layer may be provided on the substrate or on the cover member. The supply hole may be provided on the substrate or on the cover member as long as it can supply the test liquid to the culture space. From the viewpoint of suppressing contamination of the medium layer, it is preferable that the supply hole is provided at a position that does not face the medium layer in a plan view of the culture sheet.

[0013] Hereinafter, the embodiments of the present invention will be described in more detail with reference to the drawings. In the following description, the same members are designated by the same reference numerals, and detailed description thereof will not be repeated. The embodiments shown in the drawings can be arbitrarily combined.

[0014] [Embodiment 1] Fig. 1 is a perspective view showing a culture sheet according to one embodiment of the present invention. Fig. 2 is a cross-sectional view showing a cross section taken along line II' in Fig. 1. Fig. 3 is a cross-sectional view showing a culture sheet according to another embodiment of the present invention.

[0015] (Culture sheet) As shown in Figs. 1 and 2, the culture sheet 1 of this embodiment has a substrate 10, a culture medium layer 20, and a cover member 30. The substrate 10 has a recess 15 on a first surface 11, and the cover member 30 is provided so as to cover the recess 15 on the first surface 11. As a result, a culture space 22 is formed so as to be surrounded by the recess 15 of the substrate 10 and the cover member 30 (Figs. 2 and 3). The substrate 10 and the cover member 30 are usually laminated to form the culture space 22. The culture medium layer 20 is provided in the recess 15, and is thereby disposed in the culture space 22. In the culture sheet 1, the entire culture medium layer 20 may be provided in the recess 15 as shown in Fig. 1.

[0016] As described above, in the culture sheet 1, the substrate 10 supports the medium layer 20, and the cover member 30 covers the surface of the medium layer 20. The cover member 30 contacts the substrate 10 in an area of ​​the first surface 11 of the substrate 10 where the recesses 15 are not formed. The substrate 10 and the cover member 30 may be fixed at the contact position by adhesion, heat welding, or the like. The contact position can be provided so as to surround the outer periphery of the medium layer 20.

[0017] The surface where the first surface 11 of the base material 10 and the first surface 11 of the cover member 30 come into contact may be subjected to a mirror finish treatment in order to improve adhesion between the first surface 11 and the cover member 30. Alternatively, as described below, when the base material 10 and the cover member 30 are formed of resin, the base material 10 and the cover member 30 may be heat-welded. This allows the first surface 11 and the cover member 30 to be in close contact with each other, so that even if the test liquid spreads outside the recess 15, it is easy to prevent the test liquid from leaking out from between the first surface 11 and the cover member 30.

[0018] The substrate 10 and the cover member 30 may be stacked in a peelable manner so that the medium layer 20 is exposed, or may be stacked in a non-peeling manner so that the culture space 22 is formed. When the substrate 10 and the cover member 30 are peeled off so that the medium layer 20 is exposed, the substrate 10 and the cover member 30 may be completely separated, or may be separated so that the medium layer 20 is exposed while a part of the substrate 10 is fixed. "Peeling" means that the substrate 10 and the cover member 30 can be separated by hand so that the medium layer 20 is exposed without damaging the substrate 10 and the cover member 30, and "non-peeling" means that at least one of the cover member 30 and the substrate 10 is damaged when the substrate 10 and the cover member 30 are separated by hand so that the medium layer 20 is exposed.

[0019] In the culture sheet 1, as shown in Fig. 2, a gap is preferably formed between the surface of the medium layer 20 and the cover member 30. The gap can be formed so that the distance between the surface of the medium layer 20 opposite the substrate 10 side and the surface of the cover member 30 facing the medium layer 20 is, for example, 0.1 to 3.0 mm, preferably 0.3 to 2.0 mm.

[0020] The culture sheet 1 has a supply hole 24 for supplying the test liquid to the culture space 22. The supply hole 24 can be provided so as to supply the test liquid to the culture space 22, and can be provided in at least one of the substrate 10 and the cover member 30. One or two or more supply holes 24 may be provided in the culture sheet 1, for example, two or more supply holes 24 may be provided in the cover member 30, or one or more supply holes 24 may be provided in each of the substrate 10 and the cover member 30.

[0021] In the culture sheet 1 shown in FIG. 1, the supply hole 24 is provided in the cover member 30. The supply hole 24 is provided so as to penetrate the cover member 30. The supply hole 24 is usually provided so that the test liquid supplied to the culture space 22 is inoculated into the culture medium layer 20. The supply hole 24 may be provided in a position of the cover member 30 that does not face the culture medium layer 20 in a plan view of the culture sheet 1, and may be provided, for example, outside the outer periphery of the culture medium layer 20. The supply hole 24 is preferably provided in a region surrounded by the above-mentioned contact position where the base material 10 and the cover member 30 contact each other in a plan view of the culture sheet 1. As shown in FIGS. 1 to 3, the supply hole 24 can be provided in a region of the cover member 30 that is outside the outer periphery of the culture medium layer 20 and faces the recess 15 provided in the base material 10 in a plan view of the culture sheet 1. An inclined portion 16 may be provided in a region of the first surface 11 of the base material 10 that faces the supply hole 24 in a plan view of the culture sheet 1. The inclined portion 16 can be formed in a recess 15 provided in the substrate 10. The inclined portion 16 is preferably formed in a tapered shape such that the height of the first surface 11 decreases from the region facing the supply hole 24 toward the culture medium layer 20 (FIG. 3). The height of the first surface 11 on the culture medium layer 20 side of the inclined portion 16 is preferably the same as the surface of the culture medium layer 20 (the surface opposite the substrate 10) or higher than the surface of the culture medium layer 20. This makes it easier for the test liquid supplied from the supply hole 24 to flow onto the surface of the culture medium layer 20.

[0022] The shape of supply hole 24 in a plan view is not particularly limited, and may be, for example, a circle, a semicircle, or a polygon such as a triangle, a rectangle, or a square, or a combination of these. The size of supply hole 24 may be any size that allows the test liquid to be supplied by a pipette or the like, and when it is a circle as shown in Fig. 1, for example, the diameter may be 3 to 15 mm, or 5 to 10 mm.

[0023] In the culture sheet 1, since the substrate 10 has the recess 15, even if a cover member 30 having a flat third surface 33 facing the culture medium layer 20 is placed on the first surface 11 of the substrate 10 as shown in Figs. 2 and 3, a culture space 22 can be formed between the substrate 10 and the cover member 30. Therefore, in the culture sheet 1, the culture medium layer 20 supported by the substrate 10 can be placed in the culture space 22 surrounded by the recess 15 of the substrate 10 and the cover member 30. As a result, the culture medium layer 20 is covered by the cover member 30 even before the culture sheet 1 is used, so that the culture medium layer 20 can be prevented from being contaminated by microorganisms other than the specimen.

[0024] When the culture sheet 1 is used, the test liquid can be supplied to the culture space 22 from the supply hole 24 provided in the cover member 30 by a pipette or the like, so that the test liquid can be inoculated into the medium layer 20 covered by the cover member 30. This allows the test liquid to be inoculated into the medium layer 20 without opening the cover member 30 to expose the medium layer 20. As described above, the base material 10 has an inclined portion 16 that is tapered toward the medium layer 20 in the portion facing the supply hole 24 (FIG. 3), so that the test liquid supplied from the supply hole 24 easily flows onto the surface of the medium layer 20. After the test liquid is supplied, the cover member 30 may be lightly pressed from above as necessary to spread the test liquid over the entire medium layer 20. Thereafter, the culture sheet 1 is placed in an incubator or the like set at a temperature and humidity suitable for the growth of the specimen, and the specimen is cultured. Colonies generated in the medium layer 20 after the culture can be observed through the cover member 30. In this way, the culture sheet 1 can prevent the medium layer 20 from being contaminated by microorganisms other than the specimen even during use, and allows culture to be performed in a state where contamination is suppressed. In addition, in order to prevent water from evaporating from the medium layer 20 during culture, a film-like covering member that covers or exposes the supply hole 24 may be provided, a lid may be provided on the supply hole 24, or a valve structure may be added to the supply hole 24.

[0025] As described above, the culture sheet 1 can prevent the medium layer 20 from being contaminated with microorganisms other than the specimen both before and during use. In addition, since the supply hole 24 is provided at a position of the cover member 30 that does not face the medium layer 20, it is easy to prevent microorganisms other than the specimen from being mixed into the medium layer 20 through the supply hole 24 both before and during use of the culture sheet.

[0026] The substrate 10 has a recess 15, and the recess 15 forms the culture space 22, so that the test liquid is supplied into the recess 15 through the supply hole 24. In particular, when the supply hole 24 is provided in a region of the cover member 30 facing the recess 15 in a plan view of the culture sheet 1, the test liquid can be easily supplied into the recess 15. The recess 15 is formed such that the first surface 11 of the substrate 10 is partially recessed, so that the test liquid supplied to the culture space 22 remains within the recess 15, making it difficult for the test liquid to spread outside the culture space 22.

[0027] To facilitate management of the culture sheet 1, various information such as a manufacturing ID such as a manufacturing lot and a serial number, manufacturer information, various symbols indicating the type of product, and an expiration date may be provided to the culture sheet 1. Such information may be provided by directly printing on the base material 10 or the cover member 30 of the culture sheet 1, or by attaching a sticker or the like.

[0028] Each component of the culture sheet 1 will be described in more detail below. Figures 4 to 6 are cross-sectional views that typically show a culture sheet according to another embodiment of the present invention. Figure 7 is a perspective view that typically shows a culture sheet according to another embodiment of the present invention. (base material) The substrate 10 can be a member that is entirely sheet-like or flat in plan view, and has a first surface 11 and a second surface 12 that is the surface opposite to the first surface 11.

[0029] As described above, the base material 10 has a recess 15 on the first surface 11. The recess 15 may have a shape and size that can accommodate the entire medium layer 20 and has a region facing the supply hole 24 in a plan view of the culture sheet 1. In a plan view of the culture sheet 1, the plan view shape of the region of the recess 15 where the medium layer 20 is provided may or may not be similar to the plan view shape of the medium layer 20. In a plan view of the culture sheet 1, the region of the recess 15 facing the supply hole 24 can be provided outside the outer periphery of the medium layer 20.

[0030] For example, in a plan view of the culture sheet 1, the recess 15 may have a circular portion 15a and a protruding portion 15b in which a part of the circular portion 15a protrudes toward the outer periphery (FIG. 1). The shape of the protruding portion 15b in a plan view is not limited, and may be a circle, a semicircle, a polygon such as a rectangle or a hexagon, or a U-shape (FIG. 1). The circular portion 15a of the recess 15 may be an area where the medium layer 20 is placed, and the protruding portion 15b may be an area facing the supply hole 24 in a plan view of the culture sheet 1. The protruding portion 15b of the substrate 10 may have the above-mentioned inclined portion 16 (FIG. 3).

[0031] In the above, the recess 15 has been described as having the circular portion 15a and the protruding portion 15b, but the shape of the recess 15 is not limited thereto. For example, the recess 15 may have a shape that has the circular portion 15a and does not have the protruding portion 15b. In this case, a region that faces the supply hole 24 in a plan view of the culture sheet 1 may be provided within the circular portion 15a and outside the outer periphery of the medium layer 20.

[0032] The depth of the recesses 15 may be adjusted depending on the thickness of the medium layer 20. It is preferable to set the depth of the recesses 15 so that when the medium layer 20 is provided in the recesses 15, the position of the surface of the medium layer 20 does not exceed the position of the first surface 11 in the region where the recesses 15 are not formed (so that the position is lower than the first surface 11) in the cross section of the culture sheet 1. The depth of the recesses 15 may be, for example, 0.1 to 5 mm, 0.2 to 3 mm, or 0.5 to 2 mm.

[0033] The recess 15 may be formed in a tapered shape such that the area in a plan view decreases from the first surface 11 toward the second surface 12 (FIG. 2).

[0034] In the above, a case where one recess 15 is provided in the base material 10 has been described, but the present invention is not limited to this. For example, when the culture sheet 1 has two or more medium layers 20, two or more recesses 15 may be formed, and one medium layer 20 may be disposed in one recess 15.

[0035] The recess 15 may be formed by three-dimensionally processing a sheet member or a plate-like member for forming the base material 10, or may be formed by cutting the sheet member or the plate-like member. As described later, when the base material 10 is formed using a resin, the recess 15 may be formed by resin molding using a mold, such as injection molding, blow molding, and press molding.

[0036] 2 and 3, the second surface 12 of the substrate 10 may have a convex shape corresponding to the shape of the recesses 15 formed on the first surface 11. The convex shape of the second surface 12 may be a deformation of the second surface 12 as a result of forming the recesses 15 on the first surface 11. The substrate 10 having the recesses 15 on the first surface 11 and the second surface 12 having a convex shape can be formed by three-dimensional processing of a sheet member or a plate-like member, resin molding, or the like.

[0037] In the above, the case where the second surface 12 of the substrate 10 has a convex shape has been described, but the second surface 12 may not have a convex shape and may be a flat surface.

[0038] The planar shape of the substrate 10 is not particularly limited, and may be, for example, a circle, a semicircle, or a polygon such as a rectangle or a hexagon, or may be a combination of these. The planar shape of the substrate 10 is preferably a quadrangle, more preferably a rectangle or a square. As shown in FIG. 1, the substrate 10 may have at least one side of the planar shape cut out, or at least one corner may be chamfered. The size of the substrate 10 in plan view is not particularly limited, but when the substrate 10 has a substantially quadrangular shape as shown in FIG. 1, each side is, for example, 40 to 100 mm, and preferably 70 to 90 mm. The thickness of the substrate 10 is not particularly limited, but is, for example, 0.1 to 3 mm, and preferably 0.5 to 2 mm.

[0039] The substrate 10 may have stacking ribs 8 to suppress misalignment when the culture sheets 1 are stacked (FIG. 1). The stacking ribs 8 can be provided in an area other than the medium layer 20 provided on the substrate 10. For example, when the substrate 10 is a polygon such as a square, the stacking ribs 8 can be provided at the corners. The stacking ribs 8 can be formed in a convex shape from the first surface 11 to the second surface 12 of the substrate 10, and are preferably formed in a tapered shape tapering toward the second surface 12. The stacking ribs 8 thus formed form a concave opening on the first surface 11 of the substrate 10, and the size of this opening in a plan view may be formed to a size that allows the tip of the stacking rib 8 on the second surface 12 side to be inserted. As a result, when the culture sheets 1 are stacked, the tip of the stacking rib 8 on the second surface 12 side of the upper culture sheet 1 is inserted and fixed into the opening on the first surface 11 side of the stacking rib 8 of the lower culture sheet 1, so that the position of the stacked culture sheets 1 can be suppressed from being misaligned in the horizontal direction.

[0040] The material constituting the substrate 10 is not particularly limited, and examples thereof include resin, paper, glass, metal, and ceramic, among which resin is preferable. Examples of the resin constituting the substrate include thermoplastic resin. Examples of the thermoplastic resin include at least one selected from the group consisting of polyolefins such as polyethylene, polypropylene, polymethylpentene, polybutene-1, ethylene-tetracyclododecene-copolymer, and ethylene-2-norbornene resin; polyesters such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycyclohexylene dimethylene terephthalate, and hydroxybenzoic acid polyester; polyacrylonitrile, acrylonitrile-styrene resin, butadiene resin, acrylonitrile-butadiene-styrene resin, polyphenylene ether, polyetherimide, polyacetal, polyarylate, polyarylsulfone, polystyrene, polyamide (nylon), polycarbonate, (meth)acrylic resin, poly(meth)acrylic styrene, polyester carbonate, polybutylene succinate, and 3-hydroxybutyric acid-3-hydroxyhexanoic acid copolymer. The substrate may contain additives such as plasticizers, lubricants, surface modifiers, pigments, dyes, and fillers in addition to the resin.

[0041] The substrate 10 may have a single-layer structure or a multi-layer structure of two or more layers. When the substrate 10 has a multi-layer structure, the materials of the layers may be the same or different.

[0042] (medium layer) The culture medium layer 20 is an area in which a specimen is cultured. In the culture sheet 1, the culture medium layer 20 is provided on the substrate 10. The culture medium layer 20 can be a culture medium in a dry state (dry culture medium). The dry culture medium can be made into a state in which a specimen can be cultured by adding water.

[0043] The medium layer 20, which is a dry medium, contains one or more components selected from the group consisting of a binder, a gelling agent, a nutrient component, a color indicator, and a selection agent. The medium layer 20 can be formed by mixing these components in a solvent to prepare a medium liquid, applying the liquid to a member that forms the medium layer 20 (the first surface 11 of the substrate 10 in the culture sheet 1), and drying the liquid. Examples of methods for applying the medium liquid include screen printing and gravure printing, including a metal mask method, application with a dispenser, and spraying with a spray method.

[0044] The binder is used to adhere the culture medium layer 20 to the first surface 11 of the substrate 10. Examples of the binder include polymer compounds that dissolve in a solvent, and may be polymer compounds that dissolve in at least one of water and an organic solvent, or may be amphipathic polymer compounds that dissolve in both of these. Examples of the binder include polyvinylpyrrolidone, polyethylene oxide, hydroxypropyl cellulose, polyvinyl alcohol, polyethyleneimine, and polyacrylic acid. One or more types of binders may be used.

[0045] The gelling agent is used to absorb water in a test liquid containing a specimen, gelling it, and provide a necessary place for the growth of the specimen (microorganism). Examples of the gelling agent include thickening polysaccharides such as guar gum, xanthan gum, locust bean gum, tara gum, tamarind seed gum, and carrageenan; cellulose derivatives such as hydroxyethyl cellulose and carboxymethyl cellulose; sodium polyacrylate, alginic acid, and the like. One or more types of gelling agents can be used.

[0046] Nutrients are necessary for the growth of the specimen, and are used to provide nitrogen sources, carbon sources, inorganic salts, vitamins, etc. Examples of nitrogen and carbon sources include peptone (casein, meat, soybeans, etc.), and examples of inorganic salts and vitamins include extracts such as yeast extract, potassium monohydrogen phosphate, sodium chloride, etc.

[0047] Color indicators are used to make colonies more visible by coloring them, and are colored by changes in pH or enzymes produced by the sample. Examples of color indicators include tetrazolium salts such as triphenyltetrazolium chloride and tetrazolium violet; pH indicators such as neutral red, phenol red, and bromothymol blue; and enzyme substrates for color indicators such as 5-bromo-4-chloro-3-indolyl-β-D-galactopyranoside (X-Gal) and 5-bromo-4-chloro-3-indolyl phosphate.

[0048] The selective agent is used to suppress the growth of microorganisms other than the bacteria to be detected. Examples of the selective agent include surfactants such as bile salts, sodium deoxycholate, and sodium lauryl sulfate, dyes such as crystal violet and brilliant green, and inorganic salts such as sodium thiosulfate, lithium chloride, and sodium azide.

[0049] The solvent is used to mix the components contained in the medium layer, and includes water, organic solvents, and mixtures thereof. Examples of organic solvents include lower alcohols such as methanol, ethanol, 1-propanol, and 2-propanol. The solvent can be used alone or in combination of two or more.

[0050] The shape of the medium layer 20 in plan view is not particularly limited, and may be, for example, a circle, a semicircle, or a polygon such as a triangle, a rectangle, or a square, or may be a combination of these. The shape of the medium layer 20 in plan view is preferably a circle. The size of the medium layer 20 in plan view is not particularly limited, but when it is a circle as shown in Fig. 1, the diameter may be 40 to 80 mm, or 50 to 60 mm.

[0051] (Cover material) The cover member 30 may be in the form of a sheet or a plate. The cover member 30 has a third surface 33 which is the surface facing the culture medium layer 20, and a fourth surface 34 which is the surface opposite to the third surface 33. The cover member 30 is preferably transparent so that colonies occurring in the culture medium layer 20 can be easily observed. The cover member 30 preferably has gas permeability suitable for culturing a specimen.

[0052] As described above, the cover member 30 of the culture sheet 1 has the supply hole 24 for supplying the test liquid to the culture space 22. The supply hole 24 can be formed by punching, cutting, laser processing, or the like of the cover member 30.

[0053] The cover member 30 may be a separate member from the substrate 10, or may be formed by a part of the substrate 10. When the cover member 30 is a separate member from the substrate 10, it is preferable that the cover member 30 is attached to the substrate 10 in advance. For example, as shown in FIG. 1, one side of the cover member 30 may be attached to the substrate 10 by a fixing means such as adhesion or riveting. The fixing position of the cover member 30 may be the first surface 11 or the second surface 12 of the substrate 10. When the cover member 30 is formed by a part of the substrate 10, the substrate 10 may be folded in half, for example, to form the region of the substrate 10 where the medium layer 20 is not formed into the cover member 30 that covers the medium layer 20.

[0054] The planar shape of the cover member 30 is not particularly limited as long as it can cover the culture medium layer 20, and may be, for example, a circle, a semicircle, or a polygon such as a rectangle or a hexagon, or a combination of these. The size of the cover member 30 in a planar view may be any size that can cover the culture medium layer 20, but is preferably larger than the culture medium layer 20. The size of the cover member 30 in a planar view may be smaller than, the same as, or larger than the size of the substrate 10.

[0055] The thickness of the cover member 30 is not particularly limited, but is, for example, 0.01 to 3 mm, preferably 0.01 to 1 mm, may be 0.02 to 0.5 mm, or may be 0.02 to 0.1 mm.

[0056] The third surface 33 and the fourth surface 34 of the cover member 30 may be flat as shown in Figs. 1 to 3. Alternatively, as shown in Figs. 4 to 6, the cover member 30 may have a protrusion 31 protruding from the third surface 33, and the protrusion 31 may surround the outer periphery of the medium layer 20 provided on the substrate 10 and contact the substrate 10 to form the culture space 22. When the supply hole 24 is provided in the cover member 30, the supply hole 24 is disposed in a region surrounded by the protrusion 31 in a plan view of the cover member 30. It is preferable that the protrusion 31 contacts a region of the first surface 11 of the substrate 10 that is outside the recess 15. Thereby, even if the test liquid leaks outside the recess 15, the test liquid can be prevented from spreading outside the culture space 22 by the protrusion 31.

[0057] The protrusions 31 may be provided intermittently in a plan view of the cover member 30, but are preferably provided continuously, and more preferably provided in an annular shape. The annular shape formed by the protrusions 31 is not limited to a circular shape, and may be a polygonal shape or any other shape, as long as it can surround the entire outer periphery of the culture medium layer 20. The protrusions 31 may be provided inside the outer edge of the cover member, as shown in Figs. 4 to 6.

[0058] The cross-sectional shape of the convex portion 31 in the cross section of the culture sheet 1 (cross section passing through the medium layer 20) may be a semicircular shape (FIG. 4), a polygonal shape such as a triangular shape (FIG. 5) or a rectangular shape (FIG. 6), or a combination of these. As shown in FIGS. 4 and 5, etc., the cross-sectional shape of the convex portion 31 is preferably such that the width of the convex portion 31 narrows toward the tip, and the height of the surface of the convex portion 31 gradually increases toward the tip. When the convex portion 31 is provided in a ring shape, the cross-sectional shape of the convex portion 31 may be the same around the entire circumference, or different shapes may be combined.

[0059] The cross-sectional shape of the protrusion 31 has at least one vertex, and preferably, in the covered state, at least the vertex contacts the first surface 11 of the substrate 10. The vertex of the protrusion 31 that contacts the first surface 11 may be one or more. Examples of a shape having at least one vertex include a circular arc shape as shown in FIG. 4, a triangular shape (FIG. 5) formed so as to contact the first surface 11 of the substrate 10 at the vertex, a sawtooth shape, and a sine wave shape. The protrusion 31 only needs to have a vertex on the surface facing the first surface 11 in the covered state of the cover member 30, and for example, as shown in FIG. 6, an uneven surface having a vertex may be formed on the surface of the rectangular protrusion 31 that faces the first surface 11.

[0060] As described above, the convex portion 31 comes into contact with the first surface 11 at its apex, so that the convex portion 31 and the first surface 11 are in point contact in the cross section. This makes it easier to suppress seepage of the test liquid due to capillary action when the test liquid reaches the contact position between the convex portion 31 and the first surface 11. Therefore, it is possible to further suppress the test liquid from spreading outside the culture space 22. On the other hand, as shown in FIG. 6, when the convex portion 31 and the first surface 11 are in surface contact in the cross section, the test liquid is more likely to seep out due to capillary action at the contact portion between the convex portion 31 and the first surface 11, so that when the test liquid spreads outside the recess 15, the test liquid is more likely to spread outside the culture space 22 due to capillary action.

[0061] The cover member 30 having the convex portion 31 may be formed by three-dimensionally processing a sheet member or a plate-like member for forming the cover member 30, or may be formed by cutting the sheet member or the plate-like member. Alternatively, the cover member 30 may be formed by attaching the convex portion 31 to a sheet member or a plate-like member by adhesion or the like, or by forming the convex portion 31 by pattern formation, printing, or coating. As described later, when the cover member 30 is formed using a resin, the convex portion 31 may be formed by resin molding using a mold such as injection molding, blow molding, and press molding. When the cover member 30 is obtained by resin molding, it is expected that the occurrence of warping in the cover member 30 during molding can be suppressed by having the convex portion 31.

[0062] The surface of the cover member 30 opposite to the surface on which the convex portions 31 are formed may be a flat surface as shown in Figs. 4 to 6, or may have a concave shape corresponding to the shape of the convex portions 31. This concave shape may be formed by deformation of the surface on the opposite side to the surface on which the convex portions 31 are formed as a result of forming the convex portions 31. The cover member 30 having such a shape can be formed by three-dimensional processing of a sheet member or a plate-like member, resin molding, or the like.

[0063] In order to facilitate the operation of opening the cover member 30 so as to expose the medium layer 20, as shown in FIG. 7, the cover member 30 may have a gripping portion 36. For example, the gripping portion 36 may be a portion of one side of the cover member 30 that protrudes from the substrate 10 in a plan view of the culture sheet 1. The gripping portion 36 may be provided on a portion that is lifted when the cover member 30 is opened. In a plan view of the culture sheet 1, for example, when the cover member 30 is fixed to one side of the substrate 10, the gripping portion 36 may be provided on one side opposite to the one side. By having the gripping portion 36 on the cover member 30, only the cover member 30 can be gripped without gripping the substrate 10, and the cover member 30 can be in an uncovered state.

[0064] The cover member 30 may have an auxiliary layer formed thereon, which contains, for example, one or more selected from the group consisting of binders, gelling agents, nutritional components, and color indicators, so as to include an area facing the culture medium layer 20 (for example, an area facing the recess 15 in a plan view of the culture sheet 1). The auxiliary layer may contain a component that cannot be mixed with the culture medium layer 20 formed on the substrate 10. The auxiliary layer may be formed on the entire third surface 33 of the cover member 30. Examples of the binder, gelling agent, nutritional component, and color indicator include those described above.

[0065] The cover member 30 may have a grid pattern (scale) printed by gravure printing or the like to make it easier to check the size of the colonies and to count the colonies. The ink used for printing is preferably insoluble in water and does not affect the growth of the specimen. The grid pattern may be, for example, 10 mm square.

[0066] The material constituting the cover member 30 is not particularly limited, and examples thereof include resin, paper, glass, metal, and ceramic, but is preferably resin. Examples of the resin constituting the cover member 30 include one or more types selected from the group consisting of polyolefins such as polyethylene and polypropylene; polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polystyrene, polycarbonate, polyacrylic resins, polyamide, polyvinyl chloride, and the like. From the viewpoints of transparency, water vapor permeability, and oxygen permeability, the cover member 30 is preferably one or more types of resin selected from the group consisting of polystyrene and polyolefins.

[0067] The cover member 30 may have a single-layer structure or a multi-layer structure of two or more layers. When the base material 10 has a multi-layer structure, the materials of the layers may be the same or different. When the cover member 30 has a protrusion 31, the protrusion 31 and the portion other than the protrusion 31 may be made of the same material or different materials.

[0068] [Embodiment 2] Fig. 8 is a cross-sectional view showing a culture sheet according to another embodiment of the present invention. In Fig. 1 to Fig. 7, the culture sheet 1 in which the culture medium layer 20 is disposed in the recess 15 provided in the base material 10 has been described. However, in the culture sheet 5 of this embodiment, the base material 17 does not have a recess, and the cover member 37 has a recess 35, as shown in Fig. 8.

[0069] The culture sheet 5 has a base material 17, a culture medium layer 20, and a cover member 37. The base material 17 has a first surface 11 that is flat, and the second surface 12 may also be flat. The cover member 37 has a recess 35 on a third surface 33 that faces the culture medium layer 20, and the base material 17 covers the recess 35 provided on the third surface 33 of the cover member 37. This forms a culture space 22 surrounded by the first surface 11 of the base material 17 and the recess 35 of the cover member 37. The culture medium layer 20 can be provided on the first surface 11 of the base material 17 so as to be disposed in the culture space 22.

[0070] As described above, in the culture sheet 5, the base material 17 supports the medium layer 20, and the cover member 37 covers the surface of the medium layer 20 at the recessed portion 35. The cover member 37 can be in contact with the base material 17 in an area of ​​the third surface 33 where the recessed portion 35 is not formed. The base material 17 and the cover member 30 may be fixed at the contact position by adhesion, heat welding, or the like. The base material 17 and the cover member 37 may be stacked releasably so that the medium layer 20 is exposed, or may be stacked unreleasably so as to form the culture space 22.

[0071] In the culture sheet 5, in order to prevent the test liquid from spreading outside the culture space 22, it is preferable that the surfaces where the first surface 11 of the substrate 17 and the first surface 11 of the cover member 30 contact each other are in close contact with each other, and for example, these surfaces may be subjected to a mirror finish treatment.

[0072] In the culture sheet 5, a gap is preferably formed between the surface of the medium layer 20 and the recesses 35. This gap may be formed so that the distance between the surface of the medium layer 20 opposite the base material 17 and the surface of the recesses 35 of the cover member 37 facing the medium layer 20 is 0.1 to 3.0 mm, preferably 0.3 to 2.0 mm.

[0073] The culture sheet 5 has a supply hole 24 for supplying the test liquid to the culture space 22. The supply hole 24 may be provided in at least one of the base material 17 and the cover member 37 as long as it can supply the test liquid to the culture space 22. In the culture sheet 5 shown in FIG. 8, the supply hole 24 is provided in the cover member 37. The supply hole 24 is provided so as to penetrate the cover member 37. The supply hole 24 is usually provided so that the test liquid supplied to the culture space 22 is inoculated into the medium layer 20. The supply hole 24 may be provided, for example, in the recess 35 of the cover member 37, or may be provided in a position of the recess 35 that does not face the medium layer 20 in a plan view of the culture sheet 5. The supply hole 24 may be provided in the bottom surface of the recess 35 or may be provided in the side surface of the recess 35. For example, as shown in FIG. 8, the supply hole 24 may be provided in the recess 35 outside the outer periphery of the medium layer 20 in a plan view of the culture sheet 1. In a plan view of the culture sheet 5, the first surface 11 of the base material 17 may have an inclined portion in an area facing the supply hole 24, as described in the previous embodiment with reference to Fig. 3. The shape of the inclined portion may be the shape described for the inclined portion 16 shown in Fig. 3. By providing the base material 17 with an inclined portion, the test liquid supplied from the supply hole 24 is more likely to flow onto the surface of the culture medium layer 20.

[0074] In the culture sheet 5, since the cover member 37 has the recess 35, even if the cover member 37 is placed on the flat first surface of the substrate 17, the culture space 22 can be formed between the substrate 17 and the cover member 37. Therefore, even if a step is formed between the surface of the medium layer 20 supported by the substrate 17 (the surface opposite to the substrate 17 side) and the first surface 11 of the substrate 17, the medium layer 20 can be placed in the culture space 22 surrounded by the substrate 17 and the recess 35 of the cover member 37. As a result, the medium layer 20 is covered by the recess 35 of the cover member 37 even before the culture sheet 5 is used, so that the medium layer 20 can be prevented from being contaminated by microorganisms other than the specimen.

[0075] When the culture sheet 5 is in use, the test liquid can be supplied from the supply hole 24 provided in the recess 35 of the cover member 37, so that the test liquid can be inoculated into the medium layer 20 arranged in the culture space 22. This allows the medium layer 20 to be inoculated with the test liquid without opening the cover member 37 to expose the medium layer 20, so that the medium layer 20 can be prevented from being contaminated by microorganisms other than the specimen even during use.

[0076] In this way, the culture sheet 5 can prevent the medium layer 20 from being contaminated with microorganisms other than the specimen both before and during use. In addition, since the supply hole 24 is provided at a position of the recess 35 of the cover member 37 that does not face the medium layer 20, it is easier to prevent microorganisms other than the specimen from being mixed into the medium layer 20 through the supply hole 24 both before and during use of the culture sheet.

[0077] The recesses 35 of the cover member 37 may have any shape and size that can cover the entire culture medium layer 20. In a plan view of the culture sheet 5, the plan view shape of the recesses 35 may or may not be similar to the plan view shape of the culture medium layer 20.

[0078] The depth of the recess 35 may be adjusted according to the thickness of the culture medium layer 20, and is preferably adjusted so that the above-mentioned gap is formed between the surface of the culture medium layer 20 and the recess 35. The recess 35 may be formed in a tapered shape so that the area in a plan view decreases from the third surface 33 side toward the fourth surface 34 side, as shown in Fig. 8.

[0079] In the above, a case where one recess 35 is provided in the cover member 37 has been described, but this is not limited thereto. For example, when the culture sheet 5 has two or more medium layers 20, two or more recesses 35 may be formed, and one medium layer 20 may be covered with one recess 35.

[0080] The recess 35 may be formed by three-dimensionally processing a sheet member or a plate-like member for forming the cover member 37, or may be formed by cutting the sheet member or the plate-like member. When the cover member 37 is formed using a resin, the recess 35 may be formed by resin molding using a mold, such as injection molding, blow molding, and press molding.

[0081] 8, the fourth surface 34 of the cover member 37 may have a convex shape corresponding to the shape of the recess 35 formed on the third surface 33. The convex shape of the fourth surface 34 may be a deformation of the fourth surface 34 as a result of forming the recess 35 on the third surface 33. The cover member 37 having the recess 35 on the third surface 33 and the fourth surface 34 having a convex shape can be formed by three-dimensional processing of a sheet member or a plate-like member, resin molding, or the like.

[0082] In the above, a case has been described in which the fourth surface 34 of the cover member 37 has a convex shape, but the fourth surface 34 may not have a convex shape and may be a flat surface.

[0083] As described in the previous embodiment, the cover member 37 may have a convex portion on the third surface 33. In this case, the convex portion may be provided in an area of ​​the third surface 33 of the cover member 37 where the concave portion 35 is not formed, and may be in contact with the first surface 11 of the base material 17 so as to surround the outer periphery of the culture medium layer 20.

[0084] The substrate 17 may be similar to the substrate 10 described in the previous embodiment, except that it does not have the recessed portion described above. The cover member 37 may be similar to the cover member 30 described in the previous embodiment, except that it has the recessed portion described above. The culture medium layer 20 and the supply hole 24 may also be similar to the culture medium layer 20 and the supply hole 24 described in the previous embodiment, except that it does not have the recessed portion described above.

[0085] [Embodiment 3] 1 to 8, the culture sheet 1 in which the medium layer 20 is provided on the base material 10, 17 has been described, but the culture sheet may have the medium layer 20 provided on the cover member 30, 37. Alternatively, the medium layer 20 may be provided on the base material 10, 17, and the medium layer 20 may also be provided on the cover member 30, 37. [Explanation of symbols]

[0086] 1 culture sheet, 5 culture sheet, 8 stack rib, 10 substrate, 11 first surface, 12 second surface, 15 recess, 15a circular portion, 15b protruding portion, 16 inclined portion, 17 substrate, 20 culture medium layer, 22 culture space, 24 supply hole, 30 cover member, 31 convex portion, 33 third surface, 34 fourth surface, 35 recess, 36 gripping portion, 37 cover member.

Claims

1. A culture sheet having a substrate, a culture medium layer, and a cover member, A culture space formed so as to be surrounded by the base material and the cover member, and in which the culture medium layer is disposed; A culture sheet having a supply hole for supplying a test liquid to the culture space.

2. the substrate has a recess on a first surface; the cover member is provided on the first surface so as to cover the recess, The culture space is formed by the recess and the cover member, The culture sheet according to claim 1 , wherein the culture medium layer is provided in the recess.

3. The culture sheet according to claim 2 , wherein the base material has a convex shape corresponding to a shape of the concave portion on a second surface opposite to the first surface.

4. The culture sheet according to any one of claims 1 to 3, wherein the supply hole is provided in the cover member.

5. The culture sheet according to claim 4 , wherein the supply hole is provided in a position of the cover member that does not face the culture medium layer in a plan view.

6. The culture sheet according to any one of claims 1 to 3, wherein the base material and the cover member are peelably laminated so that the culture medium layer is exposed.

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