Carrier for analysis, method for producing carrier for analysis, and analysis method

Abstract

This carrier for analysis (1) comprises a metal member (10) that includes a porous body (20). The porous body (20) includes a skeleton (22) that is formed by assembling a plurality of aluminum particles (21), and a plurality of voids (23) that are surrounded by the skeleton (22). The skeleton (22) has, on the surfaces of the aluminum particles (21), an outer shell (24) that includes an anodic oxide coating that contains aluminum oxide. The porosity of the porous body (20) is 30% by volume or more. The average particle diameter of the plurality of aluminum particles (21) is 0.1 µm to 20 µm. The organic acid concentration of the metal member (10) is 150 mg / m2 / 100 µm or less.

Description

Analytical carrier, method for producing analytical carrier, and analytical method

[0001] The present disclosure relates to an analytical carrier, a method for producing an analytical carrier, and an analytical method.

[0002] Immunochromatography is known as one type of analytical method for analyzing an analyte carried on an analytical carrier (see Patent Document 1). Lateral flow test kits using immunochromatography are also known. These test kits include a test strip in which a capture antibody that reacts with the analyte is immobilized at a predetermined site on the analytical carrier.

[0003] In this test kit, for example, a specimen containing an antigen to be analyzed is collected from a living organism, and a solution containing the specimen is dropped onto a predetermined position on a test strip. The antigen then reacts with a labeled antibody labeled with particles such as colloidal gold particles and latex particles to form a complex. The solution containing the complex then flows through the analytical carrier by capillary action. Furthermore, as the solution containing the complex is developed by the analytical carrier, the antigen contained in the complex is captured by the capture antibody on the analytical carrier, and the complex accumulates at the capture site, resulting in color development. In this way, the degree of color development at the capture site with the complex supported by the analytical carrier can be visually confirmed to determine whether the specimen contains the antigen.

[0004] Japanese Patent Application Laid-Open No. 2003-344406

[0005] In Patent Document 1, a nitrocellulose membrane filter is used as the analytical carrier. Nitrocellulose membrane filters generally have a high degree of whiteness, making it relatively easy to visually confirm the test line and control line, and have excellent development performance due to capillary action. For these reasons, they are used in many test kits.

[0006] Meanwhile, fluorescence measurement is one type of analytical technique that utilizes immunochromatography. In fluorescence measurement, for example, an analyte is reacted with an antibody labeled with fluorescent beads to form a complex, and the complex is then reacted with a capture antibody immobilized on an analytical carrier. Subsequently, excitation light of a specific wavelength is irradiated onto the analytical carrier carrying the analyte, and fluorescence emitted from the fluorescent beads is detected, thereby performing a fluorescent analysis of the analyte. In this case, the fluorescence emitted from the fluorescent beads bound to the capture antibody and the analyte serves as a signal, while fluorescence emitted from other sources serves as noise. However, when a nitrocellulose membrane filter is used as the analytical carrier, it itself emits high levels of autofluorescence, which hinders high sensitivity.

[0007] The present disclosure has been made in view of the problems inherent in the conventional techniques, and an object of the present disclosure is to provide an analytical carrier capable of suppressing autofluorescence, a method for manufacturing the analytical carrier, and an analytical method using the analytical carrier.

[0008] An analytical support according to a first aspect of the present disclosure is an analytical support comprising a metal member including a porous body. The porous body includes a skeleton formed by an assembly of a plurality of aluminum particles and a plurality of voids surrounded by the skeleton. The skeleton has an outer shell including an anodized film containing aluminum oxide on the surface of the aluminum particles. The porosity of the porous body is 30% by volume or more. The average particle diameter of the plurality of aluminum particles is 0.1 μm to 20 μm. The organic acid concentration of the metal member is 150 mg / m ２ / 100 μm or less.

[0009] A method for producing an analytical support according to a second aspect of the present disclosure is a method for producing an analytical support provided with a metal member including a porous body. The porous body includes a skeleton formed by an assembly of a plurality of aluminum particles and a plurality of voids surrounded by the skeleton. The skeleton has an outer shell including an anodized film containing aluminum oxide on the surface of the aluminum particles. The production method includes a sintering step of sintering a plurality of aluminum metal particles to obtain a sintered body, and an anodizing step of anodizing the sintered body to form an outer shell including an anodized film on the surface of the aluminum metal particles. The average particle diameter of the plurality of aluminum metal particles is 0.1 μm to 20 μm. The packing ratio of the sintered body is 20 vol % to 70 vol %. The organic acid concentration of the metal member is 150 mg / m ２ / 100 μm or less.

[0010] An analytical method according to a third aspect of the present disclosure is an analytical method for analyzing an analyte supported on an analytical carrier. The analytical carrier is an analytical carrier comprising a metal member including a porous body. The porous body includes a skeleton formed by an assembly of a plurality of aluminum particles and a plurality of voids surrounded by the skeleton. The skeleton has an outer shell including an anodized film containing aluminum oxide on the surface of the aluminum particles. The porosity of the porous body is 30% by volume or more. The average particle diameter of the plurality of aluminum particles is 0.1 μm to 20 μm. The organic acid concentration of the metal member is 150 mg / m ２ The analysis method includes an irradiation step of irradiating the analytical carrier carrying the analyte with light having at least one wavelength included in the ultraviolet to infrared region, and a detection step of detecting at least one type of light selected from the group consisting of reflected light, scattered light, transmitted light, fluorescence, and phosphorescence of the irradiated light.

[0011] FIG. 1 is a schematic cross-sectional view showing an enlarged structure of a portion of a porous body of an analytical carrier according to one embodiment. FIG. 2 is a cross-sectional view showing an example of a metal member according to one embodiment. FIG. 3 is a perspective view showing an example of a test strip using an analytical carrier according to one embodiment. FIG. 4 is a scanning image of a test strip for autofluorescence measurement according to Example 3 and Reference Example 1 at an excitation wavelength of 488 nm. FIG. 5 is a scanning image of a test strip for autofluorescence measurement according to Example 3 and Reference Example 1 at an excitation wavelength of 532 nm. FIG. 6 is a scanning image of a test strip on which antibodies according to Example 3 and Reference Example 1 are immobilized at an excitation wavelength of 488 nm. FIG. 7 is a scanning image of a test strip on which antibodies according to Example 3 and Reference Example 1 are immobilized at an excitation wavelength of 532 nm. FIG. 8 is a graph showing the relationship between total organic acid concentration and autofluorescence intensity. FIG. 9 is a graph showing the relationship between total inorganic acid concentration and autofluorescence intensity.

[0012] The analytical carrier, the manufacturing method of the analytical carrier, and the analytical method according to the present embodiment will be described in detail below with reference to the drawings. The present disclosure is not limited to the following embodiments. Furthermore, some or all of the components in the embodiments can be combined as appropriate. Note that the dimensional proportions in the drawings are exaggerated for the sake of explanation and may differ from the actual proportions.

[0013] [1. Analytical Carrier] First, the analytical carrier according to this embodiment will be described. Conventionally, when a nitrocellulose membrane filter is used as an analytical carrier, the filter itself emits high autofluorescence, which hinders high sensitivity. Therefore, in the analytical carrier according to this embodiment, the organic acid concentration of the metal member is reduced. As will be described in detail later, it has been discovered that the analytical carrier according to this embodiment can suppress the autofluorescence of the analytical carrier by reducing the organic acid concentration. Note that autofluorescence is also called autofluorescence or primary fluorescence, and refers to fluorescence generated by the inherent characteristics of the analytical carrier.

[0014] <Porous body> Fig. 1 is a schematic cross-sectional view showing an enlarged structure of a portion of the porous body 20 of the analytical carrier 1. As shown in Fig. 1, the analytical carrier 1 includes a metal member 10, which includes a porous body 20. The porous body 20 includes a plurality of aluminum particles 21. Furthermore, the porous body 20 includes a plurality of voids 23. More specifically, the porous body 20 includes a skeleton 22 formed by an aggregation of the plurality of aluminum particles 21, and the voids 23 surrounded by the skeleton 22. The skeleton 22 includes an outer shell 24, and the surface of the skeleton 22 is formed by the outer shell 24. In the porous body 20, the plurality of aluminum particles 21 are connected via the outer shell 24 to form the skeleton 22 with a three-dimensional network structure, and the outer shell 24 is disposed on the outer surface side of the analytical carrier 1.

[0015] In this way, the porous body 20 is a porous body having voids 23 therein that communicate with the outside. In this case, the voids 23 are surrounded by the outer shell 24. That is, the voids 23 are formed by being surrounded by the skeleton 22 inside the porous body 20 or the outer shell 24 formed on its surface. The voids 23 forming one cell structure surrounded by the outer shell 24 may be connected to the voids 23 forming another cell structure. Specifically, the porous body 20 may have an open-cell structure. Furthermore, the single void 23 or multiple voids 23 may or may not penetrate from one surface to the other surface of the porous body 20.

[0016] The analytical carrier 1 includes a porous body 20. The porous body 20 is obtained by sintering an aluminum powder containing a plurality of aluminum particles 21, or by compacting the aluminum powder to obtain a green compact, and then subjecting the sintered body to an anodizing process described below. The porous body 20 includes a skeleton 22 formed by an aggregation of the plurality of aluminum particles 21. The porous body 20 also includes voids 23 surrounded by the skeleton 22. The skeleton 22 has an outer shell 24 on the surface of the aluminum particles 21.

[0017] Here, in immunochromatography, labels such as fluorescent beads are used, as will be described later. When the analytical carrier 1 is used, for example, in an immunochromatographic test strip, the porous body 20 can absorb the solution in which the label is dispersed by capillary action. This is thought to occur as the solution in which the label is dispersed penetrates into the spaces in the voids 23 present inside the porous body 20, and a portion of it flows along the surface of the porous body 20.

[0018] The average particle diameter of the plurality of aluminum particles 21 is 0.1 μm to 20 μm. By setting the average particle diameter to 0.1 μm or more, the strength of the porous body 20 is improved, and breakage during transportation, etc. can be suppressed. By setting the average particle diameter to 20 μm or less, the flow rate of the analytical carrier 1 can be improved. The average particle diameter may be 1 μm or more, 3 μm or more, or 5 μm or more. The average particle diameter may be 18 μm or less, 15 μm or less, or 10 μm or less.

[0019] The average particle diameter of the plurality of aluminum particles 21 can be measured by observing the cross section of the porous body 20 with a scanning electron microscope. For example, after sintering, the aluminum particles 21 are partially melted and connected, but the portions having a substantially circular shape can be considered approximately circular. Therefore, in the above-mentioned cross-sectional observation, the maximum diameter (longest diameter) of each of the substantially circular aluminum particles 21 is defined as the particle diameter, and the particle diameters of 50 randomly selected aluminum particles 21 are measured. The arithmetic average of these is defined as the average particle diameter of the sintered aluminum particles 21. The average particle diameter of the plurality of aluminum metal particles before sintering is the D50 value obtained by measuring the particle size distribution on a volume basis using a laser diffraction method. Note that, within the range of 0.1 μm to 20 μm, almost no secondary particles are formed. Therefore, the average particle diameter of the sintered aluminum particles 21 observed with a scanning electron microscope is substantially the same as the average particle diameter of the aluminum metal particles before sintering measured with a laser diffraction method.

[0020] The shape of each aluminum particle 21 is not particularly limited and may be spherical, polygonal, irregular, scale-like, fibrous, or the like. Among these, it is preferable that each aluminum particle 21 contained in the plurality of aluminum particles has a spherical shape. When each aluminum particle 21 has a spherical shape, the size of the plurality of voids 23 becomes uniform. For example, in immunochromatography, as described below, labels such as fluorescent beads are used. If the size of the voids 23 is uniform, such labels are not captured within the voids 23 and can flow smoothly through the porous body 20. Note that the term "spherical" as used here does not only refer to a perfect sphere, but also to a particle having a slight unevenness on the surface. Furthermore, the term "spherical" as used here does not only refer to particles having an aspect ratio of 1, but also includes particles having an aspect ratio of 5 or less, 3 or less, or 2 or less. The aspect ratio is the ratio of the major axis to the minor axis of the aluminum particle 21, and is the average value of the plurality of aluminum particles 21.

[0021] The average pore diameter of the porous body 20 is preferably 2.5 μm to 20 μm. By setting the average pore diameter to 2.5 μm or more, the water wicking performance of the analytical carrier 1 can be improved. Here, the particle diameter of typical fluorescent beads used in immunochromatography is approximately 10 nm to 50 nm, and labels with larger particle diameters also exist. When the analytical carrier 1 is used, for example, in an immunochromatographic test strip, setting the average pore diameter to 2.5 μm or more prevents such labels from being trapped within the voids 23 and allows them to flow smoothly through the porous body 20. Furthermore, setting the average pore diameter to 20 μm or less can improve the water wicking performance of the analytical carrier 1. The average pore diameter may be 3 μm or more, or may be 4 μm or more. The average pore diameter may be 15 μm or less, or may be 10 μm or less. The average pore diameter can be measured by mercury intrusion porosimetry. In this specification, the average pore size means the median size on a volume basis.

[0022] The porosity of the porous body 20 is 30% by volume or more. The porosity of the porous body 20 may be 30% to 99% by volume. By setting the porosity of the porous body 20 to 30% by volume or more, the water absorbing performance can be improved. By setting the porosity to 99% by volume or less, peeling of the aluminum particles 21 from the porous body 20 can be suppressed, and the strength of the porous body 20 can be improved. The porosity may be 40% by volume or more, 50% by volume or more, 60% by volume or more, 70% by volume or more, 80% by volume or more, 90% by volume or more, or 92% by volume or more. The porosity may be 95% by volume or less, or 93% by volume or less. The porosity is the ratio of the volume of pores in the porous body 20 to the total volume of the porous body 20. The porosity can be obtained by dividing the pore volume occupied by the voids 23 contained in the porous body 20 portion, which is obtained by submerging the analytical carrier in water and evacuating it, by the apparent volume of the porous body 20 portion, as described in the Examples section below.

[0023] The thickness of the porous body 20 is preferably 20 μm to 10 cm. By making the thickness of the porous body 20 20 μm or more, it becomes easier to ensure a sufficient thickness for absorbing water by capillary action. By making the thickness of the porous body 20 10 cm or less, it is possible to prevent the porous body 20 from cracking even when it is wound on a roll for transportation, etc. The thickness of the porous body 20 is preferably 30 μm or more, more preferably 40 μm or more, and even more preferably 50 μm or more. The thickness of the porous body 20 is more preferably 1000 μm or less, even more preferably 200 μm or less, and particularly preferably 150 μm or less.

[0024] The porous body 20 may be composed of a single porous layer, or may include multiple porous layers. The porous body 20 may include, for example, a first porous layer and a second porous layer disposed on the surface of the first porous layer. The first porous layer and the second porous layer may differ in any of the average particle size, aspect ratio, or constituent material of the multiple aluminum particles 21, the porosity of the porous body 20, or the average pore size. For example, the average particle size of each aluminum particle 21 contained in the first porous layer may be larger than the average particle size of each aluminum particle 21 contained in the second porous layer. Furthermore, the thicknesses of the first porous layer and the second porous layer may be the same or different.

[0025] <Outer Shell> The outer shell 24 includes an anodized film containing aluminum oxide. The anodized film included in the outer shell 24 may be a barrier-type anodized film or a porous-type anodized film. The outer shell 24 may have only a barrier-type anodized film formed on the surface of the aluminum particle 21, or may have a two-layer structure in which a barrier-type anodized film is formed on the surface of the aluminum particle 21 and a porous-type anodized film is further formed on the outside. The outer shell 24 may have a hydrated film containing aluminum hydroxide. The hydrated film is formed in the hydration treatment step described below.

[0026] The outer shell 24 preferably has a thickness of 0.1 nm to 1000 nm. By setting the thickness of the outer shell 24 within this range, an analytical carrier 1 with sufficiently high corrosion resistance can be provided. The thickness of the outer shell 24 may be 1 nm or more, or 10 nm or more. The thickness of the outer shell 24 may be 200 nm or less, or 100 nm or less. The thickness of the outer shell 24 can be measured, for example, by observing a cross section of the outer shell 24 with a scanning electron microscope or the like.

[0027] <Metallic Member> As shown in Fig. 2, the metallic member 10 may further include a substrate 50. That is, the metallic member 10 may include only the porous body 20 and, optionally, the substrate 50. Alternatively, the metallic member 10 may include only the porous body 20 and the substrate 50. Alternatively, the metallic member 10 may include only the porous body 20. The substrate 50 can support the porous body 20 and can improve the rigidity of the analytical support 1. The substrate 50 may have a layered or plate-like shape.

[0028] The porous body 20 may be provided on at least one surface of the substrate 50. Specifically, the porous body 20 may be provided on only one surface of the substrate 50, or on both surfaces of the substrate 50. The porous body 20 is preferably disposed on the outermost surface of the analytical carrier 1.

[0029] The analytical carrier 1 does not necessarily have to include the substrate 50, and therefore the thickness of the substrate 50 is greater than 0 μm. The thickness of the substrate 50 depends on the application, but may be, for example, 1 mm or less, 100 μm or less, 10 μm or less, or 1 μm or less.

[0030] The substrate 50 can be made of the same material as the aluminum particles 21. Specifically, the substrate 50 may contain at least one of aluminum and an aluminum alloy. That is, the metal member 10 may be an aluminum member. The material constituting the substrate 50 may be the same as or different from the material constituting the aluminum particles 21.

[0031] The thickness of the metal member 10 may be, for example, 20 μm or more and 10 cm or less, depending on the application. By setting the thickness of the metal member 10 within this range, an analytical carrier 1 with good bending strength can be provided. The thickness of the metal member 10 may be 30 μm or more, 50 μm or more, 100 μm or more, or 150 μm or more. The thickness of the metal member 10 may be 1000 μm or less, 300 μm or less, or 200 μm or less.

[0032] The organic acid concentration of the metal member 10 is 150 mg / m ２ / 100 μm or less. By setting the organic acid concentration of the metal member 10 to the above value or less, it is possible to suppress the generation of autofluorescence from the porous body 20. Furthermore, by setting the organic acid concentration of the metal member 10 to the above value or less, when fluorescence measurement is performed on the analytical carrier 1 after a flow test in which a solution containing an analyte is passed through the analytical carrier 1, it is possible to reduce the background signal intensity and noise value emitted from areas other than the spot where the analyte is detected. In this way, the analytical carrier 1 makes it easier to detect signals from the spot derived from the analyte with high sensitivity when performing an analysis in which excitation light is irradiated onto the analytical carrier 1 and the emitted light is detected.

[0033] Although the analytical carrier 1 according to this embodiment is not limited to the following mechanism, it is believed that the suppression of autofluorescence by reducing the organic acid concentration is due to the low concentration of conjugated systems in the anodized film of the porous body 20. Generally, the presence of conjugated systems, such as double bonds and benzene rings, generates fluorescence. As described below, anodized films are produced by anodization in an electrolyte, and components contained in the electrolyte are incorporated into the anodized film during anodization. Since organic acids themselves do not emit fluorescence, it is believed that when an organic acid is contained in the electrolyte, the organic acid in the electrolyte undergoes oxidation, resulting in the formation of organic acid-derived compounds containing conjugated systems. That is, when anodization is performed in an electrolyte containing an organic acid, organic acid-derived compounds are generated from the organic acid incorporated into the anodized film, or organic acid-derived compounds generated in the electrolyte are incorporated into the anodized film, resulting in the porous body 20 containing organic acid-derived compounds. It is believed that when the organic acid concentration measured from the metal member 10 is high, the autofluorescence increases due to an increase in fluorescence generated from the conjugated system of the organic acid-derived substance contained in the porous body 20. Furthermore, when anodization is performed in an electrolyte containing an organic acid and the anodized film becomes thick, it is believed that the autofluorescence increases due to the incorporation of a large amount of organic acid or organic acid-derived substance into the anodized film.

[0034] As described in the Examples section below, the organic acid concentration is the total content of organic acids in an extract obtained by extracting the metal member 10 of the analytical carrier 1 with a liquid containing water. The organic acid concentration is calculated by the ratio of the total organic acid content of the metal member 10 having a thickness of 100 μm to the total organic acid content of the metal member 10 having a projected area of ​​1 m ２ The organic acid concentration refers to the content of organic acids contained per unit mass. The organic acid concentration can be calculated by ion analysis using the extract. The ion analysis can be performed by ion chromatography and ICP atomic emission spectrometry, as described in the Examples section below.

[0035] The anodized film may be an organic acid anodized film or an inorganic acid anodized film. An organic acid anodized film suppresses the denaturation of proteins such as antibodies bound to the analytical carrier 1, thereby suppressing a decrease in signal intensity from labels such as fluorescent substances. This improves the signal-to-noise ratio. The organic acid anodized film refers to an anodized film in which the concentration of organic acid eluted from the anodized film is higher than the concentration of inorganic acid. The organic acid anodized film may have an organic acid concentration of 60% or more, 70% or more, 80% or more, or 90% or more of the total of the organic acid concentration and the inorganic acid concentration. The inorganic acid anodized film refers to an anodized film in which the concentration of inorganic acid eluted from the anodized film is higher than the concentration of organic acid. The inorganic acid anodized film may have an inorganic acid concentration of 60% or more, 70% or more, 80% or more, or 90% or more of the total of the organic acid concentration and the inorganic acid concentration. The organic acid anodized film can be formed by anodizing with an electrolytic solution containing an organic acid. The inorganic acid anodized film can be formed by anodizing with an electrolytic solution containing an inorganic acid. The organic acid concentration can be measured by the method described above, and the inorganic acid concentration can be measured by a similar method. Anodization will be described later.

[0036] The anodized film may be at least one selected from the group consisting of a citric acid anodized film, an adipic acid anodized film, and an oxalic acid anodized film. These organic acid anodized films are less likely to denature proteins such as antibodies bound to the analytical carrier 1, thereby suppressing a decrease in signal intensity from labels such as fluorescent substances. This improves the signal-to-noise ratio. The citric acid anodized film refers to an anodized film in which the highest concentration of organic acids eluted from the anodized film is citric acid. The adipic acid anodized film refers to an anodized film in which the highest concentration of organic acids eluted from the anodized film is adipic acid. The oxalic acid anodized film refers to an anodized film in which the highest concentration of organic acids eluted from the anodized film is oxalic acid. The concentrations of these organic acids can be measured by ion analysis, similar to the method described above.

[0037] The anodized film may be at least one selected from the group consisting of a sulfuric acid anodized film, a phosphoric acid anodized film, and a boric acid anodized film. These inorganic acid anodized films have a low organic acid concentration in the metal component 10. This suppresses the generation of autofluorescence from the analytical carrier 1 and reduces the background signal intensity and noise value after a flow test. The sulfuric acid anodized film is an anodized film in which the inorganic acid eluted from the anodized film is sulfuric acid at the highest concentration. The phosphoric acid anodized film is an anodized film in which the inorganic acid eluted from the anodized film is phosphoric acid at the highest concentration. The boric acid anodized film is an anodized film in which the inorganic acid eluted from the anodized film is boric acid at the highest concentration. These inorganic acid concentrations can be measured by ion analysis, similar to the method described above.

[0038] The anodized film may be at least one selected from the group consisting of a citric acid anodized film, an adipic acid anodized film, an oxalic acid anodized film, a phosphoric acid anodized film, and a boric acid anodized film. Such anodized films are less likely to cause denaturation of proteins such as antibodies bound to the analytical carrier 1, and therefore can suppress a decrease in signal intensity from labels such as fluorescent substances. This can improve the signal-to-noise ratio.

[0039] The anodized film may be a weak acid anodized film. Such an anodized film is less likely to cause denaturation of proteins such as antibodies bound to the analytical carrier 1, thereby suppressing a decrease in signal intensity from labels such as fluorescent substances. This can improve the signal-to-noise ratio. The weak acid anodized film refers to an anodized film in which the acid eluted from the anodized film with the highest concentration is a weak acid. The weak acid anodized film may be at least one selected from the group consisting of citric acid anodized film, adipic acid anodized film, oxalic acid anodized film, phosphoric acid anodized film, and boric acid anodized film.

[0040] <Analytical Carrier> As described above, the analytical carrier 1 according to this embodiment is an analytical carrier 1 including a metal member 10 containing a porous body 20. The porous body 20 includes a skeleton 22 formed by an aggregation of a plurality of aluminum particles 21, and a plurality of voids 23 surrounded by the skeleton 22. The skeleton 22 has an outer shell 24 including an anodized film containing aluminum oxide on the surface of the aluminum particles 21. The porosity of the porous body 20 is 30% by volume or more. The average particle diameter of the plurality of aluminum particles 21 is 0.1 μm to 20 μm. The organic acid concentration of the metal member 10 is 150 mg / m ２ / 100 μm or less.

[0041] In the analytical carrier 1 according to this embodiment, the low organic acid concentration in the metal member 10 suppresses autofluorescence emitted from the porous body 20. Furthermore, the low organic acid concentration in the metal member 10 reduces the background signal intensity and noise value after a flow test. Therefore, the analytical carrier 1 can provide an analytical carrier 1 capable of detecting signals from spots derived from the analyte with high sensitivity.

[0042] The analytical carrier 1 may be an analytical carrier 1 for performing fluorescence analysis in which fluorescence emitted by irradiating the analytical carrier 1 with excitation light is measured. The analytical carrier 1 according to this embodiment can suppress autofluorescence, and therefore can be suitably used as a carrier for fluorescence analysis.

[0043] The wavelength of the irradiated excitation light may be 250 nm to 650 nm, and the wavelength of the measured fluorescence may be 350 nm to 700 nm. Such excitation wavelengths and fluorescence wavelengths are widely used in general fluorescence analysis, and therefore the analytical carrier 1 according to this embodiment can be widely used.

[0044] The analytical carrier 1 according to this embodiment allows analysis of the analyte while supporting the analyte. The analytical carrier 1 suppresses autofluorescence and can also suppress background signal intensity and noise, making it suitable for use as an immunochromatographic test strip. Note that immunochromatographic test strips are also referred to as immunochromatographic developing members, lateral flow assay test strips, or lateral flow assay developing members. Furthermore, the analytical carrier 1 is also preferably used in in vitro diagnostic pharmaceuticals such as test kits that utilize immunochromatography.

[0045] As described above, the analytical carrier 1 can absorb liquid by capillary action due to the porous body 20, and thus can be used in lateral flow assays. The flow rate, which represents the speed at which the analytical carrier 1 absorbs liquid in the longitudinal direction, is not particularly limited, but may be, for example, 1500 seconds or less. This makes it possible to provide an analytical carrier 1 suitable for, for example, chromatography. The flow rate may be 1000 seconds or less, 500 seconds or less, 300 seconds or less, 200 seconds or less, or 100 seconds or less. The flow rate can be obtained by immersing the analytical carrier 1 in pure water at room temperature (30°C) so that the planar direction of the analytical carrier 1 is perpendicular to the liquid surface and measuring the time required for the water to be absorbed by capillary action to a height of 4 cm. The pure water has a resistivity of 10 kΩ-m measured at 30°C.

[0046] [2. Manufacturing Method of Analytical Support] Next, a manufacturing method of the analytical support 1 according to this embodiment will be described. The manufacturing method of the analytical support 1 according to this embodiment includes a sintering step and an anodizing step. Furthermore, the manufacturing method of the analytical support 1 may include a hydration step, if necessary. A sintered material including a sintered body in which a plurality of aluminum metal particles are sintered is obtained by the sintering step. The sintered material may further include a base material. Furthermore, the sintered body is subjected to a hydration step and an anodizing step, if necessary. That is, the sintered material including the sintered body is subjected to a hydration step and an anodizing step, if necessary, to obtain a metal member 10 including a porous body 20. Each step will be described in detail below.

[0047] <Sintering Step> In the sintering step, a plurality of aluminum metal particles are sintered to obtain a sintered body. Each aluminum metal particle contains at least one of pure aluminum and an aluminum alloy.

[0048] The purity of pure aluminum may be 99.00% by mass or more, 99.50% by mass or more, 99.80% by mass or more, 99.99% by mass or more, or 99.995% by mass or more. Pure aluminum may contain elements other than aluminum (Al). The elements other than aluminum contained in pure aluminum may include one or more of silicon (Si), iron (Fe), copper (Cu), manganese (Mn), magnesium (Mg), chromium (Cr), zinc (Zn), titanium (Ti), vanadium (V), gallium (Ga), nickel (Ni), boron (B), zirconium (Zr), etc. The content of each element other than aluminum contained in pure aluminum may be less than 1% by mass, or less than 0.01% by mass.

[0049] An aluminum alloy contains aluminum and elements other than aluminum. The elements other than aluminum contained in the aluminum alloy may include one or more of silicon (Si), iron (Fe), copper (Cu), manganese (Mn), magnesium (Mg), chromium (Cr), zinc (Zn), titanium (Ti), vanadium (V), gallium (Ga), nickel (Ni), boron (B), zirconium (Zr), etc. The total content of the elements other than aluminum contained in the aluminum alloy may be more than 1 mass%. The total content of the elements other than aluminum contained in the aluminum alloy may be 10 mass% or less, or may be 5 mass% or less. The content of each of the elements other than aluminum contained in the aluminum alloy may be 10 mass% or less, or may be 1 mass% or less. Hereinafter, at least one of pure aluminum and an aluminum alloy will be simply referred to as aluminum.

[0050] The aluminum metal particles have an average particle size of 0.1 to 20 μm. The average particle size of the aluminum metal particles before sintering is the D50 value obtained by measuring the particle size distribution on a volume basis using a laser diffraction method. The shape of the particles is not particularly limited, and may be spherical, polygonal, irregular, scaly, fibrous, or the like.

[0051] The aluminum metal particles can be produced by a known method. The aluminum metal particles can be produced, for example, by an atomization method, a melt spinning method, a rotating disk method, a rotating electrode method, or other rapid solidification methods. Among these, from the viewpoint of industrial productivity, the aluminum metal particles are preferably produced by an atomization method, and more preferably by a gas atomization method. Specifically, the aluminum metal particles are preferably produced by atomizing a molten metal.

[0052] The plurality of aluminum metal particles may be disposed on at least one surface of the substrate and then sintered. On at least one surface of the substrate, aluminum powder containing a plurality of aluminum metal particles may be disposed, or a green compact obtained by compacting the aluminum powder may be disposed, or a liquid composition such as a slurry containing a plurality of aluminum metal particles may be disposed. The liquid composition may be applied to the surface of the substrate by a known method such as spray coating, brush coating, roller coating, air knife coating, bar coating, spin coating, dipping, or screen printing. The liquid composition may be applied to the surface of the substrate to achieve the desired thickness of the porous body 20, taking into account the composition.

[0053] Before disposing the aluminum metal particles on the surface of the substrate, the surface of the substrate may be pretreated. The pretreatment may include a step of roughening the surface of the substrate. The pretreatment is not particularly limited and may be cleaning, etching, blasting, or the like.

[0054] The substrate may contain resin or may contain metal. When the substrate contains resin, the resin is burned by sintering, and therefore the substrate can be removed from the analytical carrier 1 after sintering. On the other hand, when the substrate contains metal, the substrate 50 can be left on the analytical carrier 1. The thickness of the substrate is greater than 0 μm. The thickness of the substrate depends on the application, but may be, for example, 1 mm or less, 100 μm or less, 10 μm or less, or 1 μm or less. The metal substrate may be made of the same material as the substrate 50 described above.

[0055] The aluminum powder or composition may contain, in addition to a plurality of aluminum metal particles, a pore-forming material, a binder, a sintering aid, a surfactant, a solvent, etc., as necessary. Any of these may be known.

[0056] The content of aluminum metal particles in the composition is preferably 20% by mass or more, more preferably 30% by mass or more, and even more preferably 31% by mass or more, and is preferably 70% by mass or less, more preferably 60% by mass or less, and even more preferably 57% by mass or less.

[0057] The pore-forming material is a material that promotes the formation of voids in the sintered body. The pore-forming material may be, for example, particles containing a polymer material. The pore-forming material preferably has low solubility in the solvent described below. The polymer material may contain a polysaccharide or a resin. The polysaccharide may contain, for example, starch. The resin may contain a polyolefin such as polyethylene or polypropylene.

[0058] The average particle diameter of the pore-forming material is preferably 0.1 μm or more and 20 μm or less. By setting the average particle diameter of the pore-forming material to 0.1 μm or more, the average pore diameter can easily be set to 2.5 μm or more. By setting the average particle diameter of the pore-forming material to 20 μm or less, the average pore diameter can easily be set to 20 μm or less. The average particle diameter of the pore-forming material is more preferably 0.5 μm or more, and even more preferably 1 μm or more. Furthermore, the average particle diameter of the pore-forming material is preferably 10 μm or less, and more preferably 8 μm or less. The average particle diameter of the pore-forming material is the D50 value determined by measuring the particle size distribution on a volume basis by laser diffraction.

[0059] The content of the pore-forming material in the composition is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 12% by mass or more. The content of the pore-forming material in the composition is preferably 30% by mass or less, more preferably 25% by mass or less, and even more preferably 23% by mass or less. When the content of the pore-forming material is equal to or greater than the lower limit of the above range, the formation of voids in the sintered body is promoted, and the packing rate of the sintered body is reduced, making it easier to obtain a sintered body having a desired packing rate and a porous body 20 having a desired porosity. Furthermore, when the content of the pore-forming material is equal to or less than the upper limit of the above range, an excessive decrease in the packing rate of the sintered body is prevented, making it easier to suppress a decrease in the strength of the porous body 20.

[0060] The binder preferably has high solubility in the solvent described below. The binder may contain, for example, a synthetic resin such as a carboxy-modified polyolefin resin, a vinyl acetate resin, a vinyl chloride resin, a vinyl chloride-vinyl acetate copolymer resin, a vinyl alcohol resin, a butyral resin, a vinyl fluoride resin, an acrylic resin, a polyester resin, a urethane resin, an epoxy resin, a urea resin, a phenolic resin, an acrylonitrile resin, a nitrocellulose resin, paraffin wax, or polyethylene wax, or a natural resin such as wax, tar, glue, urushi, rosin, or beeswax. The content of the binder in the composition is preferably 0.5% by mass or more, and more preferably 1% by mass or more. The content of the binder in the composition is preferably 30% by mass or less, and more preferably 20% by mass or less.

[0061] The solvent may contain an organic solvent such as water, ethanol, toluene, ketones, esters, etc. To volatilize the solvent, the laminate formed by applying the composition to the substrate may be dried at a temperature of 20°C or higher and 300°C or lower for 1 minute to 30 minutes, if necessary.

[0062] The sintering temperature is not particularly limited, but is preferably 560°C or higher and 660°C or lower. By setting the sintering temperature to 560°C or higher, the strength of the porous body 20 can be improved. By setting the sintering temperature to 660°C or lower, melting of the aluminum metal particles can be suppressed. The sintering temperature is more preferably 570°C or higher, and even more preferably 580°C or higher. Furthermore, the sintering temperature is more preferably 650°C or lower, and even more preferably 620°C or lower.

[0063] The sintering time depends on the sintering temperature, etc., but may be, for example, about 5 to 24 hours. The sintering atmosphere is not particularly limited and may be, for example, a vacuum atmosphere, an inert gas atmosphere, an oxidizing gas atmosphere (air), or a reducing gas atmosphere. Among these, the sintering atmosphere is preferably a vacuum atmosphere or a reducing gas atmosphere. Furthermore, the sintering conditions may be any pressure condition of normal pressure, reduced pressure, or increased pressure.

[0064] When the composition contains a pore-forming material, it is preferable to heat the composition at a temperature of 200°C or higher and 500°C or lower before sintering. By heating the composition at 200°C or higher, the pore-forming material is burned slowly, and more uniformly dispersed voids can be formed in the sintered body. By heating the composition at 500°C or lower, oxidation of the surfaces of the aluminum metal particles during heating can be suppressed, and the strength of the porous body 20 can be improved. The heating temperature is preferably 250°C or higher, more preferably 280°C or higher. The heating temperature is preferably 460°C or lower, more preferably 430°C or lower.

[0065] The heating time is preferably 5 hours or more and 20 hours or less. By setting the heating time to 5 hours or more, more uniformly dispersed voids can be formed in the sintered body. By setting the heating time to 20 hours or less, sintering between the aluminum metal particles can be prevented from progressing, and more uniformly dispersed voids can be formed in the sintered body. The heating time is more preferably 7 hours or more, and more preferably 15 hours or less. The sintering atmosphere may be any of a vacuum atmosphere, an inert gas atmosphere, and an oxidizing gas atmosphere. Furthermore, the sintering conditions may be any of atmospheric pressure, reduced pressure, and increased pressure.

[0066] The sintering step may include a first sintered layer forming step for obtaining a first sintered layer and a second sintered layer forming step for obtaining a second sintered layer. In the first sintered layer forming step, a plurality of aluminum metal particles may be sintered to obtain the first sintered layer. As described above, the plurality of aluminum metal particles may be arranged on at least one surface of the substrate and then sintered. In the second sintered layer forming step, a laminate in which a plurality of aluminum metal particles are arranged on the surface of the first sintered layer may be sintered. In the first sintered layer forming step and the second sintered layer forming step, at least one of the average particle size, aspect ratio, constituent materials, composition of the composition, or type or average particle size of the pore-forming material used of the plurality of aluminum metal particles may be different.

[0067] The filling rate of the sintered body is 20% to 70% by volume. By setting the filling rate of the sintered body to 20% by volume or more, it becomes easier to obtain a porous body 20 having a porosity below the upper limit of the desired range after the anodizing process. This prevents aluminum metal particles from peeling off from the porous body 20, improving the strength of the porous body 20. Furthermore, by setting the filling rate of the sintered body to 70% by volume or less, it becomes easier to obtain a porous body 20 having a porosity above the lower limit of the desired range after the anodizing process. This improves the wicking performance of the porous body 20. The filling rate may be 30% by volume or more, 40% by volume or more, or 50% by volume or more. The filling rate may be 65% by volume or less, 60% by volume or less, or 55% by volume or less. As described in the Examples section below, the filling rate can be obtained by dividing the mass of the sintered body portion, obtained by subtracting the mass of the substrate portion from the mass of the entire sintered material, by the mass of the sintered body portion assuming a filling rate of 100%.

[0068] <Hydration Step> The manufacturing method of the analytical carrier 1 according to this embodiment may include a hydration step prior to the anodization step. The hydration step forms a hydrated film on the surface of aluminum metal particles, which is then converted into an oxide film during the subsequent anodization step, thereby efficiently forming an anodized film. At the same time, the hydration step also has the effect of lifting and cleaning contaminants present on the aluminum surface prior to anodization, thereby reducing the occurrence of uneven appearance when an anodized film is subsequently applied. It also suppresses the generation of fluorescence derived from organic matter adhering to the aluminum surface. The hydration step involves heat-treating the sintered body in warm water, such as boiling water. The warm water may be pure water or an aqueous phosphoric acid solution containing dissolved phosphoric acid. The concentration of the aqueous phosphoric acid solution may be, for example, 0.001 mL / L to 5 mL / L. A phosphoric acid solution of this concentration can be obtained, for example, by adjusting an 85% by weight aqueous phosphoric acid solution with pure water to the desired concentration. The addition of phosphoric acid enhances the surface cleaning effect. When the sintered body is subjected to a hydration treatment, a hydrated film of aluminum hydroxide is formed on the surface of the aluminum, and as described above, the outer shell 24 may contain the hydrated film, but the outer shell 24 may also contain the hydrated film.

[0069] <Anodizing Process> In the anodizing process, the sintered body is anodized to form an outer shell 24 including an anodized film on the surface of the aluminum metal particle. In the anodizing process, for example, an anode on which the sintered body is placed and a cathode on which stainless steel (SUS) is placed are immersed in an electrolytic solution to perform electrolysis.

[0070] In the anodization step, the sintered body may be anodized using an electrolyte containing an organic acid. By anodizing the sintered body using an electrolyte containing an organic acid, the above-mentioned organic acid anodized film can be formed. In the anodization step, the sintered body may be anodized using an electrolyte containing at least one selected from the group consisting of citric acid, adipic acid, oxalic acid, and salts thereof. Examples of these salts include ammonium salts, sodium salts, potassium salts, and silicates. By anodizing the sintered body using an electrolyte containing at least one of citric acid and a citrate salt, the above-mentioned citric acid anodized film can be formed. By anodizing the sintered body using an electrolyte containing at least one of adipic acid and an adipate salt, the above-mentioned adipic acid anodized film can be formed. By anodizing the sintered body using an electrolyte containing at least one of oxalic acid and an oxalate salt, the above-mentioned oxalic acid anodized film can be formed.

[0071] In the anodizing step, the sintered body may be anodized using an electrolyte containing an inorganic acid. By anodizing the sintered body using an electrolyte containing an inorganic acid, the above-mentioned inorganic acid anodized film can be formed. In the anodizing step, the sintered body may be anodized using an electrolyte containing at least one selected from the group consisting of sulfuric acid, phosphoric acid, boric acid, and salts thereof. Examples of these salts include ammonium salts, sodium salts, potassium salts, and silicates. By anodizing the sintered body using an electrolyte containing at least one of sulfuric acid and a sulfate, the above-mentioned sulfuric acid anodized film can be formed. By anodizing the sintered body using an electrolyte containing at least one of phosphoric acid and a phosphate, the above-mentioned phosphoric acid anodized film can be formed. By anodizing the sintered body using an electrolyte containing at least one of boric acid and a borate, the above-mentioned boric acid anodized film can be formed.

[0072] In the anodization process, an electrolyte containing a weak acid may be used for anodization. When a strong acid such as sulfuric acid is used, if the strong acid remains in the porous body 20, the strong acid may cause the protein to denature by losing its binding sites (functional groups) or changing its three-dimensional structure. In such cases, the signal intensity from labels such as fluorescent substances may decrease, resulting in a decreased signal-to-noise ratio. Therefore, the signal-to-noise ratio can be improved by using an electrolyte containing a weak acid. In this specification, a weak acid has an acid dissociation constant pKa of greater than 1.2, preferably greater than 1.8, and more preferably greater than 3.0, measured at 25°C.

[0073] In the anodization step, an electrolyte containing at least one acid selected from the group consisting of citric acid, adipic acid, oxalic acid, phosphoric acid, and boric acid may be used for the anodization. Electrolytes containing such weak acids are less likely to denature proteins, and therefore can suppress a decrease in signal intensity from labels such as fluorescent substances. This can improve the signal-to-noise ratio.

[0074] The conditions for anodization are not particularly limited. For example, the electrolysis temperature may be 0°C or higher, 10°C or higher, 20°C or higher, 30°C or higher, 40°C or higher, or 50°C or higher. The electrolysis temperature may be 70°C or lower, 60°C or lower, or 50°C or lower. The electrolysis voltage may be 0.1V or higher or 1V or higher, depending on the type of electrolyte. The electrolysis voltage may be 500V or lower or 400V or lower, depending on the type of electrolyte. The electrolysis time may be 0.1 minutes or longer or 1 minute or longer. The electrolysis time may be 60 minutes or shorter or 20 minutes or shorter. Anodization may be performed in a single step or may be performed in multiple separate steps.

[0075] As described above, the method for producing an analytical support 1 according to this embodiment is a method for producing an analytical support 1 including a metal member 10 containing a porous body 20. The porous body 20 includes a skeleton 22 formed by an assembly of a plurality of aluminum particles 21, and a plurality of voids 23 surrounded by the skeleton 22. The skeleton 22 has an outer shell 24 including an anodized film containing aluminum oxide on the surface of the aluminum particles 21. The production method includes a sintering step of sintering a plurality of aluminum metal particles to obtain a sintered body, and an anodizing step of anodizing the sintered body to form an outer shell 24 including an anodized film on the surface of the aluminum metal particles. The average particle diameter of the plurality of aluminum metal particles is 0.1 μm to 20 μm. The packing ratio of the sintered body is 20% to 70% by volume. The organic acid concentration of the metal member 10 is 150 mg / m ２ / 100 μm or less.

[0076] [3. Analysis Method] The analysis method according to this embodiment is an analysis method for analyzing an analyte carried on an analytical carrier 1. Examples of the analyte include amino acids, peptides, proteins, genes, sugars, lipids, cells, and complexes thereof. More specifically, examples of the analyte include peptides such as PCT (procalcitonin); proteins such as urinary albumin; hormones such as HCG (human chorionic gonadotropin) and LH (luteinizing hormone); HBs antigen, rotavirus antigen, adenovirus antigen, RSV (Respiratory Syndrome) antigen, and the like. viral infections such as HBs antibody, HCV (hepatitis C virus) antibody, HIV antibody, EBV antibody, RSV antibody, rubella virus antibody, measles virus antibody, enterovirus antibody, dengue virus antibody, and SARS antibody. antigens or antibodies of bacterial infections such as pneumococcal antigens, mycoplasma antigens, group A hemolytic streptococcus antigens, legionella antigens, mycobacterium tuberculosis antigens, gonococcus antigens, tetanus antigens, mycoplasma antibodies, Helicobacter pylori antibodies, and mycobacterium tuberculosis antibodies; antigens or antibodies of chlamydia infections such as chlamydia antigens; antigens or antibodies of spirochete infections such as Treponema pallidum antibodies; antigens or antibodies of protozoal diseases such as malaria antibodies and toxoplasma antibodies.

[0077] The analysis method includes an irradiation step of irradiating light and a detection step of detecting the light.

[0078] <Irradiation Step> In the irradiation step of irradiating light, the analytical carrier 1 carrying the analyte is irradiated with light having at least one wavelength ranging from the ultraviolet region to the infrared region. The irradiated light is also referred to as incident light incident on the analytical carrier 1. The irradiated light may include light rays or may be light rays. The irradiated light may have a continuous wavelength, a discontinuous wavelength, or a single wavelength.

[0079] The irradiated light may have a wavelength included in at least one region selected from the group consisting of the ultraviolet region, the visible region, and the infrared region. The wavelength in the ultraviolet region may be 10 nm or more and less than 380 nm, the wavelength in the visible region may be 380 nm or more and less than 780 nm, and the wavelength in the infrared region may be 780 nm or more and less than 1 mm. That is, the irradiated light may have any wavelength within the range of 10 nm or more and less than 1 mm. The excitation light may have a continuous wavelength, a discontinuous wavelength, or a single wavelength.

[0080] The light in the ultraviolet region may include at least one of near ultraviolet light and vacuum ultraviolet light. The near ultraviolet light may include light having a wavelength of 200 nm or more and less than 380 nm. The vacuum ultraviolet light may include light having a wavelength of 10 nm or more and less than 200 nm. The near ultraviolet light may include at least one light selected from the group consisting of UVA, UVB, and UVC. UVA may include light having a wavelength of 315 nm or more and less than 380 nm. UVB may include light having a wavelength of 280 nm or more and less than 315 nm. UVC may include light having a wavelength of 200 nm or more and less than 280 nm.

[0081] The light in the infrared region may include at least one selected from the group consisting of near-infrared, mid-infrared, and far-infrared. The near-infrared may include light having a wavelength of 780 nm or more and less than 2.5 μm. The mid-infrared may include light having a wavelength of 2.5 μm or more and less than 4 μm. The far-infrared may include light having a wavelength of 4 μm or more and less than 1 mm.

[0082] The light can be emitted by a light source, which may include, for example, an LED, a laser diode, an incandescent lamp, a halogen lamp, a tungsten lamp, a xenon lamp, a halogen lamp, a metal halide lamp, or a high-pressure mercury lamp.

[0083] <Detection Step> The detection step of detecting light is a step of detecting at least one type of emitted light selected from the group consisting of reflected light, scattered light, transmitted light, fluorescence, and phosphorescence of irradiated light. By detecting the intensity of such light with a detector, information on the analytical carrier 1 in a state in which the analyte is supported can be obtained. The detector may obtain one-dimensional information (point information), two-dimensional information (line information), or three-dimensional information (stereoscopic spatial information) on the analytical carrier 1 in a state in which the analyte is supported. The detector may be capable of detecting the wavelength to be detected, and may detect light by filtering out unnecessary light using a filter or the like. The detection of the emitted light may be performed visually by observing the emitted light emitted from the analytical carrier 1 with the naked eye.

[0084] The detector may be a detector having a light receiving element such as a photomultiplier tube (PMT), a photodiode (PD), a complementary metal oxide semiconductor (CMOS) sensor, or a charge coupled device (CCD) sensor. The detector may output the detection result of the detected light to an output unit. The output unit may be, for example, a liquid crystal display, a CRT, or a printer.

[0085] [4. Test Kit] Next, an example of a test kit using the analytical carrier 1 will be described. Note that the test kit is also sometimes called a diagnostic kit. As shown in FIG. 3 , the test kit includes a test strip 100 having the analytical carrier 1. Specifically, the test strip 100 includes the analytical carrier 1, a specimen supply section 110, and an absorption section 130. The analytical carrier 1 is provided with a determination section 120. The test kit further includes a case (not shown) for storing the test strip 100.

[0086] The specimen supply unit 110 may contain, for example, a labeled antibody that specifically binds to an antigen, which is the analyte. Examples of analytes used in test kits include those similar to the analytes described above. A specimen collected from a living organism or the like is supplied to the specimen supply unit 110 and mixed with the labeled antibody to form a liquid mixture. The liquid mixture is developed to the determination unit 120 by capillary action in the analytical carrier 1, and excess specimen is absorbed by the absorption unit 130.

[0087] The determination unit 120 has, for example, a test line and a control line. For example, a capture antibody that specifically binds to the analyte is immobilized on the test line. When the analyte is contained in the sample, a labeled antibody is immobilized on the capture antibody on the test line via the analyte. For example, an antibody that specifically binds to the labeled antibody is immobilized on the control line. When the mixture containing the sample and the labeled antibody is developed up to the control line, the labeled antibody binds to the antibody immobilized on the control line.

[0088] The labeled antibody contains a label containing particles such as fluorescent beads and an antibody that binds to the label to form a complex and specifically binds to the analyte. Therefore, if there is a location where the concentration or density of the labeled antibody is high, the fluorescence of that location can be confirmed by the dense label. Therefore, if the test kit detects fluorescence from both the test line and the control line, it is a positive result, and if fluorescence is detected only from the control line, it is a negative result.

[0089] The fluorescent beads can emit fluorescence in response to excitation light. As described above, the excitation light may be light having at least one wavelength included in the ultraviolet to infrared regions. The average particle diameter of the particles may be 10 nm or more and 100 nm or less. When the average particle diameter is within the above range, the particles can flow smoothly through the porous body 20. The average particle diameter may be 70 nm or less, or may be 50 nm or less. The average particle diameter of the particles is the D50 value obtained by measuring the particle size distribution on a volume basis using a laser diffraction method.

[0090] The fluorescence can be detected by a fluorescence detector such as a fluorescence scanner, which irradiates the analytical support 1 carrying the analyte with excitation light and detects the fluorescence of the fluorescent beads excited by the excitation light.

[0091] The test kit can be used for, for example, infectious disease testing; genetic analysis; pregnancy testing; livestock testing; and allergen testing for food, animals, plants, metals, house dust, etc.

[0092] [5. Other] In the above-described embodiment, the analytical carrier 1 is used in a test strip 100 and a test kit that utilize immunochromatography. The analytical carrier 1 can be used as appropriate for any application that involves an analytical method for analyzing an analyte supported on the analytical carrier 1, in which incident light is irradiated onto the analytical carrier 1 and light emitted from the analytical carrier 1 is detected. In this case, lateral flow on the analytical carrier 1 is not essential.

[0093] In the above-described embodiment, an example in which the analyte includes an antigen and the label is bound to an antibody has been described, but the present invention is not limited to such an example. For example, the analyte may include an antibody and the label may be bound to the antigen. Furthermore, an example in which a complex is formed by utilizing an antigen-antibody reaction between an antigen and an antibody has been described, but the present invention is not limited to such an example. For example, a complex formed by the interaction of biological substances, such as the bond between biotin and avidin, can be used.

[0094] The analytical carrier 1 can also be used as, for example, a gas or liquid separation membrane; a moisture-absorbing material; a water-absorbing material; an adsorbent material for adsorbing foreign substances such as pollen, particulate matter, bacteria, odor components, and heavy metals; a wiping sheet; a test sheet for chemicals such as concentrated sulfuric acid, urinalysis, and pH testing; a disinfecting and sterilizing material; a reflective material (standard white board); a separator for batteries and electric double-layer capacitors; a catalyst carrier; a reaction site for synthetic reactions; or a heat-insulating material. Examples of the separation membrane include a reverse osmosis membrane, an ion exchange membrane, and a gas separation membrane. Examples of the adsorbent material include a mask, a filtration membrane, and a filter.

[0095] Hereinafter, the present embodiment will be described in more detail with reference to examples, comparative examples and reference examples, but the present embodiment is not limited to these.

[0096] Example 1 (Slurry Preparation) First, a slurry was prepared by uniformly dispersing 34 parts by mass of aluminum metal particles, 19 parts by mass of a pore-forming material, and 1 part by mass of a binder in 46 parts by mass of a solvent. The aluminum metal particles (AHZL58FN manufactured by Toyo Aluminum K.K.) were pure aluminum (JIS A1080) with a purity of 99.80% by mass or more. The aluminum metal particles were approximately spherical and had an average particle diameter of 3 μm. Starch (Nikka Co., Ltd., Nikka ...

[0097] (Sintering) The slurry was applied to one surface of an aluminum substrate having a thickness of 30 μm using a Comma Coater (registered trademark) manufactured by Hirano Tecseed Co., Ltd., so that the thickness of the porous body was 50 μm. The slurry was dried at 100°C for 1.5 minutes, then heated at 350°C for 5 hours in an air atmosphere, and further sintered at 620°C to 640°C for 10 hours in an argon gas atmosphere. In this way, a sintered material was produced in which a sintered body was provided on an aluminum substrate.

[0098] (Hydration Treatment) Next, the sintered material was washed with pure water at room temperature for 10 seconds. After that, the sintered material was immersed in an aqueous solution prepared by adjusting the concentration of 85% phosphoric acid aqueous solution with pure water to 0.5 mL / L at 85°C for 3 minutes to perform hydration treatment. Next, the hydrated sintered material was washed with pure water at room temperature for 30 seconds.

[0099] (Anodic oxidation) Next, the hydrated sintered material was anodized to form an outer shell containing aluminum oxide on the surface of the aluminum metal particles. Specifically, the sintered material placed on the anode and stainless steel (SUS) placed on the cathode were immersed in an electrolyte at 50°C prepared with pure water to give 4 g / L of citric acid and 0.2 g / L of triammonium citrate. Then, anodization was performed at a voltage of 1 V for 5 minutes.

[0100] After the anodization treatment, the obtained metal member was washed with pure water at room temperature for 30 seconds and dried for 15 minutes at 50° C. In this way, an analytical support according to this example was obtained.

[0101] Example 2 An analytical carrier was prepared in the same manner as in Example 1, except that the electrolysis voltage for anodization was changed to 5V.

[0102] Example 3 An analytical carrier was prepared in the same manner as in Example 1, except that the electrolysis voltage for anodization was changed to 60V.

[0103] [Example 4] An analytical carrier was prepared in the same manner as in Example 3, except that a slurry was prepared by uniformly dispersing 34 parts by mass of aluminum metal particles, 17 parts by mass of a pore-forming material, and 1 part by mass of a binder in 48 parts by mass of a solvent.

[0104] [Example 5] An analytical carrier was prepared in the same manner as in Example 3, except that 54 parts by mass of aluminum metal particles and 19 parts by mass of binder were uniformly dispersed in 27 parts by mass of solvent to prepare a slurry.

[0105] [Example 6] An analytical carrier was prepared in the same manner as in Example 3, except that 64 parts by mass of aluminum metal particles and 1 part by mass of binder were uniformly dispersed in 35 parts by mass of solvent to prepare a slurry.

[0106] Example 7 An analytical carrier was prepared in the same manner as in Example 3, except that AHU091 (trade name) manufactured by Toyo Aluminum KK, having an average particle size of 1.8 μm, was used as the aluminum metal particles.

[0107] Example 8 An analytical carrier was prepared in the same manner as in Example 3, except that aluminum metal particles manufactured by Toyo Aluminum K.K. under the trade name AHZ58CN and having an average particle size of 5 μm were used.

[0108] [Example 9] An analytical carrier was prepared in the same manner as in Example 3, except that aluminum metal particles having an average particle size of 15 μm and trade name AHZ530C manufactured by Toyo Aluminum K.K. were used, and the electrolysis voltage for anodization was set to 15 V.

[0109] Example 10 An analytical carrier was prepared in the same manner as in Example 8, except that the slurry was applied to one surface of the aluminum substrate so that the thickness of the porous body was 100 μm.

[0110] Example 11 An analytical support was prepared in the same manner as in Example 1, except that the electrolyte for anodization was prepared with pure water so that the concentration of ammonium dihydrogen phosphate was 1 g / L.

[0111] Example 12 An analytical carrier was prepared in the same manner as in Example 11, except that the electrolysis voltage for anodization was changed to 5V.

[0112] Example 13 An analytical carrier was prepared in the same manner as in Example 11, except that the electrolysis voltage for anodization was changed to 60V.

[0113] Example 14 An analytical carrier was prepared in the same manner as in Example 11, except that the electrolysis voltage for anodization was changed to 150V.

[0114] Example 15 An analytical carrier was prepared in the same manner as in Example 11, except that the electrolysis voltage for anodization was changed to 400V.

[0115] Example 16 An analytical carrier was prepared in the same manner as in Example 14, except that the electrolyte for anodization was prepared with pure water so that the concentrations of adipic acid and ammonium adipate were 5 g / L and 100 g / L, respectively.

[0116] Example 17 An analytical carrier was prepared in the same manner as in Example 14, except that the electrolyte for anodization was prepared with pure water so that the boric acid concentration was 80 g / L and the ammonium pentaborate octahydrate concentration was 0.7 g / L.

[0117] [Example 18] An analytical carrier was prepared in the same manner as in Example 1, except that the electrolyte for anodization was prepared with pure water so that the sulfuric acid concentration was 150 g / L, the electrolysis temperature was 10°C, the electrolysis voltage was 10 V, and the electrolysis time was 6 minutes.

[0118] Example 19 An analytical carrier was prepared in the same manner as in Example 18, except that the electrolysis time for anodic oxidation was set to 1 minute.

[0119] Example 20 An analytical carrier was prepared in the same manner as in Example 18, except that the electrolysis time for anodic oxidation was set to 20 minutes.

[0120] [Example 21] An analytical carrier was prepared in the same manner as in Example 1, except that the electrolyte for anodization was prepared by adding 85% by mass phosphoric acid aqueous solution to pure water to make a concentration of 40 mL / L, and the electrolysis temperature was set to 25°C, the electrolysis voltage to 10 V, and the electrolysis time to 6 minutes.

[0121] [Example 22] An analytical carrier was prepared in the same manner as in Example 1, except that the electrolyte for anodization was prepared with pure water to have an oxalic acid concentration of 50 g / L, the electrolysis temperature was 25°C, the electrolysis voltage was 10 V, and the electrolysis time was 8 minutes.

[0122] Comparative Example 1 An analytical carrier was prepared in the same manner as in Example 1, except that the electrolysis voltage for anodization was changed to 150V.

[0123] Comparative Example 2 An analytical carrier was prepared in the same manner as in Example 1, except that the electrolysis voltage for anodization was changed to 400V.

[0124] Comparative Example 3 An analytical carrier was prepared in the same manner as in Example 22, except that the electrolysis time for anodization was changed to 23 minutes.

[0125] Comparative Example 4 An analytical carrier was prepared in the same manner as in Example 22, except that the electrolysis voltage for anodization was changed to 30 V and the electrolysis time to 1 minute.

[0126] Reference Example 1 A nitrocellulose membrane filter FF80HP manufactured by Cytiva was used as the analytical carrier in this example.

[0127] [Evaluation] The analytical carriers of the examples were evaluated as follows.

[0128] (Packaging ratio) The packing ratio of the sintered body was measured by the following procedure for the sintered material before hydration treatment: ２A measurement sample of 1000 mm was cut out. Measurements and calculations were then carried out on the measurement sample. (Note that in this specification, the projected area refers to the horizontally projected area of ​​a sintered material, sintered body, porous body, metal member, analytical carrier, measurement sample, etc. when viewed in a plane in the same direction as the thickness direction.) - The mass Ma (g) of the entire sintered material, which is the combination of the sintered body and the substrate, was measured. - The thickness Wa (cm) of the entire sintered body was measured with a micrometer. - The thickness Wb (cm) of the substrate portion was measured with a micrometer. - The mass Mb (g) of the substrate portion was calculated by Mb = density of substrate × Wb × 100. In this example, the density of the material of the substrate and sintered body portion made of aluminum material was 2.7 g / cm ３ The calculation was made as follows. - The mass Mc (g) of the sintered body portion was calculated as Mc = Ma - Mb. - The mass Md (g) of the sintered body portion assuming a packing rate of 100% was calculated as Md = density of material of sintered body portion x (Wa - Wb) x projected area of ​​sintered body portion = 2.7 x (Wa - Wb) x 100. - The packing rate of the sintered body contained in the measurement sample was calculated as packing rate (%) = (Mc / Md) x 100.

[0129] (Structure of anodic oxide film) After cutting the analytical support, the cut surface was mirror-finished using a Cross Section Polisher (registered trademark) manufactured by JEOL Ltd., and the cross section was observed using an ULTRA plus scanning electron microscope manufactured by Carl Zeiss K.K. to confirm the structure of the anodic oxide film.

[0130] (Porosity) The porosity of the porous body was obtained by measuring the analytical carrier according to the following procedure. All operations were carried out at room temperature. Vacuum grease was applied to the cock of the burette to be used beforehand. 5 mL of pure water (room temperature) was placed in a 10 mL burette (±0.02 mL) with a minimum scale interval of 0.05 mL. The total thickness W1 (cm) of the analytical carrier, which is the combination of the porous body and the substrate, was measured with a micrometer. The thickness W2 (cm) of the portion of the analytical carrier other than the porous body (substrate) was measured with a micrometer. The thickness W3 of the porous body portion was calculated as W1 - W2 (cm). The apparent volume of the porous body portion was calculated by the formula W3 (cm) x projected area A (cm ２ ) = 1.00 cm３ A measurement sample with a projected area of ​​A was cut out so that the projected area of ​​A was approximately 5 mm square. The measurement sample with a projected area of ​​A was cut into pieces of approximately 5 mm square. All of the cut measurement samples were gently placed in a burette containing water and the entire sample was submerged. A rubber hose was connected to the opening of the burette, and a vacuum was applied with a vacuum pump for 1 minute to expel air from the voids contained in the porous body of the sample. The rubber hose was removed, and the liquid level after vacuuming was read (to 1 / 10 of the minimum scale). The volume of water V1 (cm), which corresponds to the volume of the solid portion contained in the entire measurement sample, was calculated from the difference between the height of the liquid level after vacuuming and the liquid level before submerging the sample. ３ The volume of the substrate portion other than the porous body portion was calculated as V2 = A × W2 (cm ３ The volume V3 (cm) of the solid portion contained in the porous body portion, excluding the void portion, was calculated. ３ The pore volume V4 occupied by the voids contained in the porous body portion was calculated as V4 = 1.00 cm ３ -V3 (cm ３ The porosity of the porous body contained in the measurement sample was calculated as follows: Porosity (%) = (V4 / 1.00) x 100.

[0131] (Thickness of anodic oxide film) After cutting the support for analysis, the cut surface was mirror-finished with a Cross Section Polisher (registered trademark) manufactured by JEOL Ltd. to obtain a sample for film thickness measurement. The cross section of this sample for film thickness measurement was observed with an ULTRA plus scanning electron microscope manufactured by Carl Zeiss K.K., and the film thickness of the anodic oxide film was measured.

[0132] (Flow Rate) The flow rate was measured as follows. First, the analytical carrier was immersed in pure water so that the plane direction of the analytical carrier was perpendicular to the liquid surface. Then, the time it took for the water to be drawn up to a height of 4 cm from the liquid surface by capillary action after immersion of the analytical carrier in pure water was measured and evaluated as the flow rate.

[0133] (Ion analysis) Using a calibration curve prepared in advance, the anions and cations extracted from the analytical carrier were quantified by ion analysis as follows. Specifically, acetate ions, formate ions, citrate ions, adipate ions, oxalate ions, phosphate ions, and sulfate ions were quantified as anions by ion chromatography. Furthermore, boron ions were quantified as a cation by ICP emission spectrometry.

[0134] Calibration curves used in ion chromatography When measuring the anions listed in Table 1 by ion chromatography, each reagent (standard solution) was diluted to prepare solutions of multiple concentrations, and a calibration curve for each anion was created.

[0135]

[0136] Extraction First, 40 analytical carriers cut into approximately 10 mm squares were prepared. ２ (0.0040m ２ ) was cut into approximately 10 mm square pieces to prepare samples for measurement. These analytical supports were placed in a 100 mL screw cock bottle, and then approximately 50 mL of 10 mM KOH aqueous solution was added. This bottle was placed in an ultrasonic cleaner (US CLEANER (US-2R) manufactured by AS ONE Corporation), and the ultrasonic cleaner was operated at high output for 20 minutes. The extract thus obtained was transferred to a measuring flask, and the solution was made up to 100 mL with 10 mM KOH aqueous solution, and this was used as the analytical sample.

[0137] Measurement of Anions Anions in the analytical sample were quantified by ion chromatography. The apparatus and conditions used for ion chromatography are as follows. Measurement sample: analytical sample obtained as described above Apparatus: Dionex (registered trademark) Integration (registered trademark) (Thermo Fisher Scientific Inc.) Column: IonPac (registered trademark) AG-11 (Thermo Fisher Scientific Inc.) Suppressor: Thermo Scientific Dionex AERS500e (Thermo Fisher Scientific Inc.) Eluent: KOH Separation conditions: Gradient Column temperature: 40°C Suppressor temperature: 20°C

[0138] Calculation of anion concentration The measured value of anion (mg / L) obtained by ion chromatography was calculated by ２ The anion concentration was calculated using the following formula (1): When the measured value was equal to or less than the lower limit of quantitation, the measured value of the anion was calculated as 0 mg / L.

[0139] Concentration of anion (mg / m ２ / 100 μm) = measured value (mg / L) × amount of sample for analysis (0.100 L) / {projected area of ​​porous body of analytical support (0.0040 m) ２ ) × <thickness of porous body (μm) / 100>} (1)

[0140] Measurement of cations The cations in the analytical sample were quantified by ICP optical emission spectroscopy. The equipment and conditions used for ICP optical emission spectroscopy are as follows: Measurement sample: A solution obtained by diluting the analytical sample used for anions twice with pure water. Equipment: High-resolution ICP analyzer SPS3100 (SII Nanotechnology Inc.) High-frequency output: 1.2 kW PMT voltage: High Wavelength: 249.774 nm BG position: 249.787 nm Number of integrations: 3 Integration time: 1 second

[0141] Calculation of cation concentration The measured value (mg / L) of the cation obtained by ICP emission spectroscopy was calculated by ２The cation concentration was calculated using the following formula (2): where the molar mass of boric acid was 61.83 g / mol and the molar mass of boron was 10.811 g / mol. When the measured value was below the lower limit of quantitation, the measured value of the cation was calculated as 0 mg / L.

[0142] Boric acid equivalent concentration (mg / m ２ / 100 μm) = (measured boron concentration (mg / L) × 61.83 / 10.811) × amount of sample for analysis (0.100 L) × 2 / {projected area of ​​porous body of analytical support (0.0040 m ２ ) × <thickness of porous body (μm) / 100>} (2)

[0143] Calibration curves used in ICP atomic emission spectrometry When measuring the cations listed in Table 2 by ICP atomic emission spectrometry, reagents (standard solutions) were diluted to prepare solutions of multiple concentrations, and calibration curves for the cations were created.

[0144]

[0145] (Autofluorescence and S / N ratio) (1) Preparation of reagents and materials First, the following reagents and materials were prepared: 1x PB (1x Phosphate Buffer) Na ２ HPO ４ ・12H ２ O (Wako Pure Chemical Industries, #197-02865) 2.9g KH ２ P.O. ４ (Wako Pure Chemical Industries, #169-04245) 0.2g Na ２ HPO ４ ・12H ２ O and KH ２ P.O. ４ Mix and dilute to 1 L with purified water. 1x PBS (1x Phosphate Buffered Saline) NaCl (Wako Pure Chemical Industries, #191-01665) 8.0 g Na ２ HPO ４ ・12H ２ O (Wako Pure Chemical Industries, #197-02865) 2.9 g KCl (Wako Pure Chemical Industries, #163-03545) 0.2 g KH ２ P.O. ４(Wako Pure Chemical Industries, #169-04245) 0.2g NaCl and Na ２ HPO ４ ・12H ２ O, KCl, and KH ２ P.O. ４ Mix the above and make up to 1 L with pure water. 1x TBS-T (1x Tris-Buffered Saline with Tween 20) Tris(hydroxymethyl)aminomethane (Dojindo Laboratories, #35401-25) 6.1 g NaCl (Wako Pure Chemical Industries, #191-01665) 8.1 g KCl (Wako Pure Chemical Industries, #163-03545) 0.2 g Mix tris(hydroxymethyl)aminomethane, NaCl, and KCl and dissolve in 900 mL of pure water, then add HCl to adjust the pH to 8.0 to prepare the first preparation solution. Add 0.5 mL of Tween 20 to the first preparation solution to prepare the second preparation solution. Make up to 1 L with pure water with the second preparation solution. Pseudo serum (1x PBS with 2% BSA and 0.05% Tween 20 dissolved in it) Antibody for membrane fixation: Human IgG derived from human serum (Sigma-Aldrich, I4506) Fluorescently labeled antibody for 488 nm: Goat Anti-Human IgG (H+L) Alexa Fluor 488 (Thermo Scientific, A11013) Fluorescently labeled antibody for 532 nm: Goat Anti-Human IgG (H+L) Alexa Fluor 555 (Thermo Scientific, A21433) Absorbent pad: Cellulose Fiber Sample Pads 20 x 300 mm 100PK (Merck Millipore, CFSP203000) Backing sheet: Pre-cut backing sheet (Nippon Engineering, 34042 / 11GL-56338)

[0146] (2) Preparation of Test Strips with Immobilized Antibodies Next, test strips with immobilized antibodies were prepared as follows. This test strip was a test piece for measuring the S / N ratio described below. The analytical carrier was cut with scissors to a size of 25 mm in length and 5 mm in width and used as a membrane for evaluation. Furthermore, the membrane immobilization antibody was diluted with 1x PBS to a concentration of 1 mg / mL to prepare an antibody immobilization solution. Using a syringe pump, 0.5 μL of the antibody immobilization solution was dripped at positions 12 mm (first spot) and 20 mm (second spot) from the bottom end of the membrane using a 2 μL microsyringe at a constant discharge rate of 0.2 μL / min. The dripped antibody immobilization solution was allowed to air dry. The membrane was placed in a glass Petri dish and placed in a thermostatic bath set at 50°C for 30 minutes to immobilize the antibody to the membrane. The membrane was attached to a backing sheet cut to a size of 60 mm in length and 5 mm in width. The absorbent pad was attached to the backing sheet so that the upper end of the membrane overlapped the lower end of the absorbent pad, which had been cut to a size of 20 mm in length and 5 mm in width, by about 2 mm. The remaining part of the backing sheet was cut off, leaving a length of about 43 mm, which was used as a test strip.

[0147] (3) Flow Test Next, a flow test was performed according to the following procedure. A fluorescently labeled antibody corresponding to the wavelength to be measured was diluted with pseudoserum to a predetermined amount to a concentration of 1 μg / mL to prepare a fluorescently labeled antibody solution. 100 μL of the fluorescently labeled antibody solution was placed into each well of a module plate. The test strip was held upright for 15 minutes, with the lower end of the test strip membrane immersed approximately 2 mm into the fluorescently labeled antibody solution in the well and the absorbent pad facing upward. The test strip was removed from the well, and a 4-well plate containing 5 mL each of 1x TBS-T, 1x TBS-T, 1x PB, and pure water was placed on a shaker. The test strip was washed in the order of the previous liquids, shaking for 5 minutes each. After washing, the test strip was air-dried on a JK Wiper 150-S (Nippon Paper Crecia Co., Ltd.) while shielded from light.

[0148] (4) Preparation of test strips for measuring autofluorescence Next, test strips for measuring autofluorescence were prepared. Test strips for measuring autofluorescence were prepared in the same manner as test strips for measuring S / N ratios, except that antibody immobilization and flow testing were not performed. That is, test strips for measuring autofluorescence were prepared using evaluation membranes prepared by cutting the analytical carrier to a predetermined size, and were directly used for measuring autofluorescence.

[0149] (5) Measurement of autofluorescence Using a fluorescence scanner (Cytiva, Amersham Typhoon scanner RGB system), excitation light was irradiated onto a test strip for measuring autofluorescence, and the fluorescence intensity (count number) of the test strip was measured. The voltage applied to the photomultiplier tube (PMT) was set to 400 V, and scanning was performed under the condition of a pixel size of 100 μm. In addition, fluorescence intensity was measured when two excitation wavelength patterns of 488 nm and 532 nm were used. When the wavelength of the excitation light was 488 nm, the wavelength of the fluorescence measured was 525 nm. When the wavelength of the excitation light was 532 nm, the wavelength of the fluorescence measured was 570 nm. The autofluorescence measurement region was a central 3 mm square region located at the midpoint between the first spot portion and the second spot portion in the length direction of the membrane, and spaced 1 mm from both ends of the membrane in the width direction. The intensity of autofluorescence was obtained by calculating the average value of the intensities of all pixels in this measurement area. As examples, scanned images of the test strips for measuring autofluorescence according to Example 3 and Reference Example 1 at an excitation wavelength of 488 nm are shown in Figure 4. Scanned images of the test strips for measuring autofluorescence according to Example 3 and Reference Example 1 at an excitation wavelength of 532 nm are shown in Figure 5.

[0150] (6) Measurement of Autofluorescence of Standard Reflector The autofluorescence of the standard reflector was measured under the same conditions as those for measuring the autofluorescence of the test strip for measuring autofluorescence (Reference Example 2). As the standard reflector, an Al standard reflector (product name: Φ20 reference plate (2 pieces), model: FAV02) (Lot No. Al-S-29) manufactured by Otsuka Electronics Co., Ltd. was used. The autofluorescence of the analytical carrier in each example was calculated as a relative value based on the measured value of the autofluorescence of the standard reflector. The pass criterion was a relative value of 2.0 or less.

[0151] (7) Measurement of S / N Ratio Using a fluorescent scanner under the same conditions as above, the fluorescence intensity (count number) of the test strip after the flow test was measured to obtain the spot intensity Isp, and the signal intensity S was calculated. The S / N ratio was then calculated by dividing the signal intensity S by the noise value Nrms as follows. As an example, scanning images of test strips on which the antibodies of Example 3 and Reference Example 1 were immobilized at an excitation wavelength of 488 nm are shown in FIG. 6. Scanning images of test strips on which the antibodies of Example 3 and Reference Example 1 were immobilized at an excitation wavelength of 532 nm are shown in FIG. 7.

[0152] The signal intensity S was calculated by subtracting the background average intensity Ib from the spot intensity Isp.

[0153] The spot intensity Isp was obtained by calculating the average value of the maximum intensity of the first spot and the maximum intensity of the second spot.

[0154] The background average intensity Ib was obtained by calculating the average intensity of all pixels in the background area of ​​the test strip after the flow test. The background area was a 3 mm square region in the center of the background area, located midway between the first and second spot areas in the length direction of the membrane and 1 mm apart from both ends of the membrane in the width direction. The background average intensity Ib was obtained by calculating the average intensity of all pixels in this measurement area.

[0155] The noise value Nrms was obtained by calculating the standard deviation of the intensities Ibi of all pixels in the background area (i is the intensity of each pixel) as shown in the following formula (3): In other words, the noise value Nrms was determined as the root mean square of the deviation between the intensity Ibi of each pixel and the average background intensity Ib. Here, n represents the total number of pixels in the background area, and i represents an integer from 1 to n.

[0156]

[0157] The preparation conditions and evaluation results of the analytical carriers for each example are shown in Tables 3 to 6.

[0158]

[0159]

[0160]

[0161]

[0162] [Discussion] Fig. 8 is a graph showing the relationship between total organic acid concentration and autofluorescence intensity. Fig. 9 is a graph showing the relationship between total inorganic acid concentration and autofluorescence intensity when irradiated with 488 nm excitation light. As shown in Fig. 8, it can be confirmed that there is a strong correlation between total organic acid concentration and autofluorescence intensity. On the other hand, as shown in Fig. 9, it can be confirmed that there is a weak correlation between total inorganic acid concentration and autofluorescence intensity when irradiated with 488 nm excitation light.

[0163] As shown in Table 4, the analytical carrier according to the example had an organic acid concentration of 150 mg / m ２ / 100 μm or less, and the analytical carrier according to the comparative example has an organic acid concentration of 150 mg / m ２ / 100 μm. Furthermore, as shown in Table 4, the analytical carriers according to the Examples had relative autofluorescence values ​​compared to an aluminum standard reflector plate of less than 2.0. On the other hand, the analytical carriers according to the Comparative Examples had relative autofluorescence values ​​compared to an aluminum standard reflector plate of greater than 2.0. Furthermore, as shown in Table 6, the analytical carriers according to the Examples had lower average background intensity and noise values ​​compared to the analytical carriers according to the Comparative Examples. Thus, it can be seen that the analytical carriers according to the Examples suppress autofluorescence signals derived from components contained in the analytical carrier, and also suppress signals emitted from areas other than the spot portion. Therefore, it can be seen that the analytical carriers according to the Examples facilitate highly sensitive detection of signals from the spot portion derived from the analyte when irradiating the analytical carrier with excitation light and detecting emitted light.

[0164] The analytical supports according to Comparative Examples 1 and 2 had a higher electrolysis voltage for anodization than the analytical supports according to Examples 1 to 3. This is thought to have resulted in the formation of a thick barrier layer in the anodized film, and the incorporation of a large amount of organic acid or organic acid-derived substance into the anodized film. ２ It is thought that the diameter exceeded 100 μm and the autofluorescence increased.

[0165] The analytical support of Comparative Example 3 had a longer electrolysis time for anodization than the analytical support of Example 22. This is thought to have resulted in a thicker porous layer of the anodized film, causing a large amount of organic acid or organic acid-derived substance to be incorporated into the anodized film. Furthermore, the analytical support of Comparative Example 4 had a shorter electrolysis time for anodization than the analytical support of Example 22, but a higher electrolysis voltage. This is thought to have resulted in a thicker barrier layer of the anodized film, causing a large amount of organic acid or organic acid-derived substance to be incorporated into the anodized film. As a result, the organic acid concentration of the metal member was 150 mg / m ２ It is thought that the diameter exceeded 100 μm and the autofluorescence increased.

[0166] Furthermore, a comparison of Examples 14, 16, and 17 with Comparative Example 1 revealed that when inorganic acids such as phosphoric acid and boric acid were used in the electrolyte, and when adipic acid was used, the organic acid concentration was lower than when citric acid was used. Furthermore, the results of Examples 18 to 21 revealed that when inorganic acids such as sulfuric acid and phosphoric acid were used, the organic acid concentration was also lower.

[0167] Furthermore, when 488 nm excitation light was irradiated onto the analytical carriers according to Examples 1 to 22, it was found that all of them exhibited low autofluorescence and low noise values ​​Nrms, thereby exhibiting an excellent S / N ratio, compared with the nitrocellulose membrane filter of Reference Example 1. Furthermore, when 532 nm excitation light was irradiated onto the analytical carriers according to Examples 1 to 16 and Example 22, it was found that all of them exhibited low autofluorescence and low noise values ​​Nrms, thereby exhibiting an excellent S / N ratio, compared with the nitrocellulose membrane filter of Reference Example 1.

[0168] When irradiated with 532 nm excitation light, the analytical supports of Examples 1 to 16 and 22 tended to have higher S / N ratios than the analytical supports of Examples 17 to 21. Here, it is possible that components of the electrolyte remaining on the anodized film could cause an increase in noise due to increased nonspecific adsorption to the analytical support, or a decrease in signal intensity due to denaturation of antibodies or fluorophores adsorbed to the anodized film. The analytical supports of Examples 1 to 10, 16, and 22, which used electrolytes containing organic acids such as citric acid, adipic acid, and oxalic acid, likely had higher S / N ratios because they suppressed the increase in noise and decrease in signal intensity that could be caused by the influence of components of the electrolyte remaining on the anodized film. The analytical supports of Examples 11 to 15, which used ammonium dihydrogen phosphate electrolytes, also likely had higher S / N ratios for the same reason.

[0169] The entire contents of Japanese Patent Application No. 2023-096908 (filing date: June 13, 2023) are incorporated herein by reference.

[0170] Although the present embodiment has been described above using examples and comparative examples, the present embodiment is not limited to these examples and comparative examples, and various modifications are possible within the scope of the gist of the present embodiment.

[0171] According to the present disclosure, it is possible to provide an analytical carrier capable of suppressing autofluorescence, a method for manufacturing the analytical carrier, and an analytical method using the analytical carrier.

[0172] REFERENCE SIGNS LIST 1 analytical carrier 10 metal member 20 porous body 21 aluminum particle 22 skeleton 23 void 24 outer shell

Claims

1. An analytical carrier comprising a metal member including a porous body, the porous body including a skeleton formed by an assembly of a plurality of aluminum particles and a plurality of voids surrounded by the skeleton, the skeleton having an outer shell including an anodized film containing aluminum oxide on the surface of the aluminum particles, the porosity of the porous body being 30 volume % or more, the average particle diameter of the plurality of aluminum particles being 0.1 μm to 20 μm, and the organic acid concentration of the metal member being 150 mg / m ２ An analytical carrier having a particle size of 100 μm or less.

2. The analytical support according to claim 1, wherein the anodic oxide film is an organic acid anodic oxide film.

3. The analytical support according to claim 1 or 2, wherein the anodic oxide film is at least one selected from the group consisting of a citric acid anodic oxide film, an adipic acid anodic oxide film, and an oxalic acid anodic oxide film.

4. The analytical support according to claim 1, wherein the anodic oxide film is at least one selected from the group consisting of a sulfuric acid anodic oxide film, a phosphoric acid anodic oxide film, and a boric acid anodic oxide film.

5. The analytical support according to claim 1, wherein the anodized film is at least one selected from the group consisting of a citric acid anodized film, an adipic acid anodized film, an oxalic acid anodized film, a phosphoric acid anodized film, and a boric acid anodized film.

6. The analytical support according to any one of claims 1 to 3 and 5, wherein the anodic oxide film is a weak acid anodic oxide film.

7. The analytical carrier according to any one of claims 1 to 6, wherein the analytical carrier is an analytical carrier for performing fluorescence analysis in which fluorescence emitted by irradiating the analytical carrier with excitation light is measured.

8. The analytical carrier according to claim 7, wherein the wavelength of the irradiated excitation light is 250 nm to 650 nm, and the wavelength of the measured fluorescence is 350 nm to 700 nm.

9. A method for producing an analytical support having a metal member including a porous body, wherein the porous body includes a skeleton formed by an assembly of a plurality of aluminum particles and a plurality of voids surrounded by the skeleton, the skeleton having an outer shell including an anodized film including aluminum oxide on the surface of the aluminum particles, the production method includes a sintering step of sintering a plurality of aluminum metal particles to obtain a sintered body, and an anodizing step of anodizing the sintered body to form the outer shell including the anodized film on the surface of the aluminum metal particles, the average particle diameter of the plurality of aluminum metal particles is 0.1 μm to 20 μm, the packing rate of the sintered body is 20 vol % to 70 vol %, and the organic acid concentration of the metal member is 150 mg / m ２ A method for producing an analytical carrier, wherein the particle size is 100 μm or less.

10. The method for producing an analytical support according to claim 9, wherein in the anodizing step, the sintered body is anodized using an electrolyte containing an organic acid.

11. A method for producing an analytical support as described in claim 9 or 10, wherein in the anodizing step, the sintered body is anodized using an electrolyte containing at least one selected from the group consisting of citric acid, adipic acid, oxalic acid, and salts thereof.

12. The method for producing an analytical support according to claim 9, wherein in the anodizing step, the sintered body is anodized using an electrolyte containing at least one selected from the group consisting of sulfuric acid, phosphoric acid, boric acid, and salts thereof.

13. The method for producing an analytical support according to claim 9, wherein the anodization step is performed using an electrolyte containing at least one acid selected from the group consisting of citric acid, adipic acid, oxalic acid, phosphoric acid, and boric acid.

14. The method for producing an analytical support according to any one of claims 9 to 11 and 13, wherein the anodization step is performed using an electrolyte containing a weak acid.

15. An analytical method for analyzing an analyte supported on an analytical support, the analytical support comprising: an analytical support having a metal member including a porous body, the porous body including a skeleton formed by an assembly of a plurality of aluminum particles and a plurality of voids surrounded by the skeleton, the skeleton having an outer shell including an anodized film containing aluminum oxide on the surface of the aluminum particle, the porosity of the porous body being 30 volume % or more, the average particle diameter of the plurality of aluminum particles being 0.1 μm to 20 μm, and the organic acid concentration of the metal member being 150 mg / m ２ / 100 μm or less, the analysis method comprising: an irradiation step of irradiating the analytical support carrying the analyte with light having at least any one of wavelengths included in the ultraviolet region to the infrared region; and a detection step of detecting at least one type of light selected from the group consisting of reflected light, scattered light, transmitted light, fluorescence, and phosphorescence of the irradiated light.

Images