JP6542997B2 - Blood cell separation membrane for immunochromatography and strip for immunochromatography - Google Patents

Description

  The present disclosure relates to an immunochromatographic blood cell separation membrane and an immunochromatographic strip.

  In recent years, the need for Point of Care Testing (POCT) has been increasing due to the shortening of examination time and the advantages of examination items, locations, and measurers. The immunochromatography method is useful for POCT, and it is possible to detect the target substance in the test sample simply and quickly only by a simple operation such as dropping the test sample such as blood or urine directly onto the test strip. it can.

  In this method, it is possible to detect a substance to be detected consisting of a specific antigen or antibody by utilizing a specific reaction between the antigen and the antibody to this. An immunochromatographic test strip generally comprises a sample pad, a conjugate pad, a chromatography medium, and an absorbent pad. When a test sample is added to the sample pad, the substance to be detected in the test sample specifically binds with the labeled antibody contained in the conjugate pad to form a complex, and the test strip is developed downstream. I will. The complex is captured by a detection antibody immobilized on a chromatography medium, and the color reaction enables detection.

  When the test sample is whole blood, when whole blood is added to the test strip as it is, the entire test strip is dyed red, which makes it very difficult to determine the color reaction. For this reason, it is necessary to separate blood cell components from whole blood before testing and use plasma or serum as a test sample, but in order to separate blood cell components, an operation such as centrifugation is necessary, and simplicity and Unfavorable from the viewpoint of quickness.

  Recently, a method of installing a blood cell separation membrane on a test strip has been developed, and a fiber-based sheet made of glass fiber, carboxymethyl cellulose (CMC) fiber or the like has been used as a blood cell separation membrane (for example, patent document 1: 2013-181870, Patent Document 2: Japanese Patent Application Publication No. 2002-350428, Patent Document 3: Japanese Patent Application Publication No. 11-248708, Patent Document 4: Japanese Patent Application Publication No. 2002-214236 and Patent Document 5: Japanese Patent Application Publication No. 2015- 72181)).

  However, in the blood cell separation membrane using a conventional fiber-based sheet, suppression of hemolysis was insufficient. When hemolysis occurs, hemoglobin is released from red blood cells, which makes it very difficult to determine the color reaction.

  Therefore, in order to solve the above-described problems, an embodiment of the present invention aims to provide an immunochromatographic blood cell separation membrane with less hemolysis and an immunochromatographic strip including the same.

The present invention includes the following aspects.
[1] A first base material having an average flow pore diameter of more than 0.06 μm and less than 1 μm and made of a hydrophilic polyolefin microporous membrane is overlapped and connected to at least a part of the first base material, a mean flow pore size x ₂ satisfying the following formula (1) when the mean flow pore size of the first base material was changed to x _1, and a second substrate comprising a hydrophilic microporous polyolefin film Hemoglobin separation membrane for immunochromatography, equipped with.
x ₁ <x ₂ <5 μm Formula (1)
[2] The blood cell separation membrane for immunochromatography according to the above [1], wherein the contact angle of the surface 1 second after dripping is 0 to 30 degrees when water is dropped onto the first base material.
[3] The blood cell separation membrane for immunochromatography according to the above [1] or [2], wherein the contact angle of the surface 1 second after dripping is 0 to 30 degrees when water is dropped onto the second base material .
[4] The immunochromatography according to any one of the above [1] to [3], wherein the length in the short direction of the overlapping portion of the first base and the second base is 1 mm or more and 5 mm or less Blood cell separation membrane for graph.
[5] In any one of the above-mentioned [1] to [4], further comprising a third base material composed of a hydrophilic fiber-based sheet, being overlapped and connected to at least a part of the second base material. The blood cell separation membrane for immunochromatography as described.
[6] The blood cell separation membrane for immunochromatography according to the above [5], wherein the length in the short direction of the overlapping portion of the third base and the second base is 1 mm or more and 5 mm or less.
[7] The immunochromatography according to any one of the above [1] to [6], wherein the film thickness of the first base material is 1 μm or more and less than 150 μm, and the porosity is 50% or more and less than 95%. Blood cell separation membrane for graph.
[8] A strip for immunochromatography, comprising the hemochromatography membrane for immunochromatography according to any one of the above [1] to [7].

  According to one embodiment of the present invention, an immunochromatographic blood cell separation membrane with less hemolysis can be provided.

FIG. 1 is a schematic view showing a schematic configuration of a blood cell separation membrane for immunochromatography according to an embodiment of the present invention. FIG. 6 is a schematic view showing a schematic configuration of a blood cell separation membrane for immunochromatography according to another embodiment of the present invention. FIG. 6 is a schematic view showing a schematic configuration of a blood cell separation membrane for immunochromatography according to still another embodiment of the present invention. FIG. 1 is a schematic view showing a schematic configuration of an immunochromatographic strip according to an embodiment of the present invention. It is the figure which showed typically the cross section of the strip for immuno chromatographs which concerns on one Embodiment of this invention. It is the figure which showed typically the cross section of the strip for immuno chromatographs which concerns on one Embodiment of this invention.

  Hereinafter, the embodiments of the present invention will be sequentially described, but these descriptions and examples illustrate the present invention and do not limit the scope of the present invention. In addition, when "-" is used in a numerical range in the whole of this specification, the upper limit and the lower limit shall be included in each numerical range.

[Hematocyte separation membrane for immunochromatography]
In one embodiment of the present invention, a first base material having an average flow pore diameter of more than 0.06 μm and less than 1 μm and made of a hydrophilic polyolefin microporous membrane, and at least a part of the first base material A _second microporous microporous membrane having an average flow pore diameter x ₂ satisfying the following formula (1), which is overlapped and connected, when the average flow pore diameter of the first base material is x ₁ , is formed of a hydrophilic polyolefin microporous membrane And a base material of 2. The blood cell separation membrane for immunochromatography, comprising:
x ₁ <x ₂ <5 μm Formula (1)

  According to one embodiment of the present invention, an immunochromatographic blood cell separation membrane with less hemolysis can be provided. Specifically, in one embodiment of the present invention, since two types of hydrophilic polyolefin microporous membranes having specific pore sizes are used in combination, blood is dropped onto the second base material, and the second In the process in which the blood penetrates from the base material to the first base material, the blood cells can be efficiently separated while sufficiently suppressing the hemolysis. And in the liquid which passed the 1st substrate, blood cells are almost completely separated, and high quality plasma can be extracted. In addition, according to the separation membrane of one embodiment of the present invention, blood cells can be separated in a short time. Therefore, it is possible to carry out the examination by the immunochromatography method simply and quickly without any special operation such as centrifugation. Furthermore, since the separation membrane of one embodiment of the present invention is configured using a microporous polyolefin membrane, the amount of elution is small, and a highly accurate inspection is also possible.

  Hereinafter, each component of one embodiment of the present invention will be described in detail.

[First base material]
In one embodiment of the present invention, the first substrate is a hydrophilic polyolefin microporous membrane having an average flow pore size of greater than 0.06 μm and less than 1 μm. Here, the microporous polyolefin membrane has a structure in which a large number of fibrillated polyolefins are linked to one another to form a three-dimensional network structure, which has a large number of micropores inside, and these micropores are connected. It is a membrane through which gas or liquid can pass from one side to the other side. Also, although the first substrate is a hydrophilic polyolefin microporous membrane, since polyolefin itself is a hydrophobic resin, the surface and / or interior of the membrane chemically or physically by the hydrophilization treatment method described later Have a hydrophilic function.

(Average flow pore size)
In one embodiment of the present invention, it is important that the average flow pore size of the first substrate is greater than 0.06 μm and less than 1 μm. If the average flow pore size of the first base material is 0.06 μm or less, the development of the plasma component after separation is not good, so that the test can not be conducted sufficiently. In such a viewpoint, the average flow pore diameter of the first base material is more preferably 0.08 μm or more, and further preferably 0.1 μm or more. When the average flow pore size of the first base material is 1 μm or more, blood cell separation at the interface between the first base material and the second base material becomes difficult, so blood cells permeate to the first base material , The separation performance is not good. In such a viewpoint, the average flow pore diameter of the first base material is more preferably 0.9 μm or less, and still more preferably 0.8 μm or less.

  Here, the average flow pore diameter of the microporous polyolefin membrane is a Pal corporation palm porometer (model: CFP-1200-AEXL), and an immersion liquid is a Pal corporation gal wick (surface tension = 15.9 dynes / cm). The average flow pore size (μm) can be determined based on the half dry method specified in ASTM E1294-89.

(Thickness)
In one embodiment of the present invention, the film thickness of the first substrate is preferably 1 to 150 μm, more preferably 5 to 130 μm, and particularly preferably 20 to 110 μm. When the film thickness of the polyolefin microporous membrane is 150 μm or less, it is preferable because a small amount of bed volume can be obtained to obtain a large amount of plasma. On the other hand, when the film thickness is 1 μm or more, sufficient mechanical strength is easily obtained, and handling properties at the time of processing of the microporous polyolefin film are also favorable, which is preferable.

(Porosity)
In one embodiment of the present invention, the porosity of the first substrate is preferably 50 to 95%, more preferably 60% to 90%. When the porosity is 50% or more, it is preferable because the spreadability of the liquid is good. On the other hand, when the porosity is 95% or less, it is preferable in that the mechanical strength of the film is improved and the handling property is also improved. Here, the porosity (ε) of the microporous polyolefin membrane is determined by the following formula (2) from the basis weight (g / m ² ), the true density (g / cm ³ ) and the thickness (μm) of the microporous polyolefin membrane Calculated by
ε (%) = {1-Ws / (ds · t)} × 100 Formula (2)
Ws: Weight (g / m ² )
ds: true density of polyolefin (g / cm ³ )
t: Film thickness (μm)

(Gare value per 1 micrometer thickness)
In one embodiment of the present invention, the Gurley value (100 cc air permeation time) per micrometer thickness of the first substrate is preferably 0.01 to 1 second / 100 cc / μm, and 0.01 to 0. More preferably, it is .6 seconds / 100 cc / μm, and particularly preferably 0.01 to 0.3 seconds / 100 cc / μm. When the Gurley value is 1.0 second / 100 cc / μm or less, it is preferable in that the spreadability of the solution is good. On the other hand, when the Gurley value is 0.01 sec / 100 cc / μm or more, the mechanical strength of the film is improved, which is preferable in that the handling property is also improved.

(Contact angle)
In one embodiment of the present invention, when the first base material is placed on a horizontal surface and water is dropped on the surface, it is preferable that the surface contact angle of the droplet after 1 second is 0 to 30 degrees And 0 to 20 degrees. When the contact angle after 1 second is 30 degrees or less, it is preferable in that the spreadability of the liquid is good.

(Polyolefin)
Although it does not specifically limit as a polyolefin composition which comprises a polyolefin fine porous film in one embodiment of this invention, For example, a polyethylene, a polypropylene, a polybutylene, polymethyl pentene, the copolymer of a polypropylene and polyethylene, etc. are mentioned. . In particular, polyethylene is preferable, and high density polyethylene and a mixture of high density polyethylene and ultrahigh molecular weight polyethylene are preferable.

As the polyolefin used in one embodiment of the present invention, it is preferable to use a polyolefin composition containing 1 to 10% by weight of ultra high molecular weight polyethylene having a weight average molecular weight of 9 × 10 ⁵ or more, and 2 to 8 ultra high molecular weight polyethylene. More preferably, it is a composition containing% by weight, and particularly preferably a composition containing 3 to 6% by weight of ultrahigh molecular weight polyethylene. In addition, by blending two or more polyethylenes in an appropriate amount, there is an effect of forming a network network structure accompanying fibrillation at the time of stretching, and increasing the porosity generation rate. It is preferable that the weight average molecular weights after mix | blending 2 or more types of polyethylene are 2 * 10 < ⁵ > -1 * 10 < ⁶ >. In particular, ultra high molecular weight polyethylene having a weight average molecular weight of 9 × 10 ⁵ or more and high density polyethylene having a weight average molecular weight of 2 × 10 ⁵ to 8 × 10 ⁵ and a density of 0.92 to 0.96 g / cm ³ And the polyolefin composition which mixed 5: 95-30: 70 by a weight ratio is preferable.

  The weight average molecular weight was determined by heating and dissolving a sample of a microporous polyolefin membrane in o-dichlorobenzene, and using GPC (Waters Corporation Alliance GPC 2000, column; GMH6-HT and GMH6-HTL), column temperature 135 ° C. , Obtained by performing measurement under conditions of flow rate 1.0 mL / min. Molecular weight monodispersed polystyrene (made by Tosoh Corporation) can be used for molecular weight calibration.

(Method for producing polyolefin microporous membrane)
In one embodiment of the present invention, the microporous polyolefin membrane can be preferably produced by the method described below. That is, (I) preparing a solution containing a polyolefin composition containing polyethylene and a volatile solvent having a boiling point of less than 210 ° C. at atmospheric pressure, (II) melt-kneading this obtained melt-kneaded product Extruding from a die and solidifying by cooling to obtain a gel-like shaped product, (III) stretching the gel-like shaped material in at least one direction (primary stretching) and drying the solvent to obtain a stretched product of the gel-like shaped product, (IV) It can be preferably produced by the step of stretching (secondary stretching) the stretched product of the gel-like molding in at least one direction.

  In step (I), a solution comprising the polyolefin composition and a volatile solvent having a boiling point of less than 210 ° C. at atmospheric pressure is prepared. Here, the solution is preferably a thermoreversible sol-gel solution, that is, the polyolefin is solubilised by heating and dissolving in the solvent to prepare a thermoreversible sol-gel solution. The volatile solvent having a boiling point of less than 210 ° C. at atmospheric pressure in the step (I) is not particularly limited as long as it can sufficiently dissolve the polyolefin. The boiling point of the solvent at atmospheric pressure is described in parentheses below, preferably tetralin (206-208 ° C), ethylene glycol (197.3 ° C), decalin (187-196 ° C), toluene (110.6 ° C) Liquid solvents such as xylene) (138-144 ° C.), diethyltriamine (107 ° C.), ethylenediamine (116 ° C.), dimethylsulfoxide (189 ° C.), hexane (69 ° C.), etc. are preferably mentioned. You may use combining a seed or more. Among them, decalin and xylene are preferable.

  In the solution of step (I), the concentration of the polyolefin composition is preferably 10 to 40% by weight, and more preferably 15 to 35% by weight, from the viewpoint of controlling the blood cell separation performance of the microporous polyolefin membrane. In addition, when the concentration of the polyolefin composition is lowered, the mechanical strength tends to be lowered, so that the handling property is deteriorated, and furthermore, the frequency of occurrence of cutting tends to increase in the formation of the microporous polyolefin membrane. In addition, when the concentration of the polyolefin composition is increased, it tends to be difficult to form pores.

  In step (II), the solution prepared in step (I) is melt-kneaded, and the obtained melt-kneaded product is extruded from a die and solidified by cooling to obtain a gel-like molding. Preferably, extrusion is performed through a die in a temperature range of the melting point to the melting point + 65 ° C. of the polyethylene composition to obtain an extrudate, and then the extrudate is cooled to obtain a gel-like shaped article. It is preferable to shape | mold in a sheet form as a molding. The cooling may be quenching to an aqueous solution or an organic solvent or casting to a cooled metal roll, but generally, a method by quenching to a volatile solvent used in water or sol-gel solution is used Be done.

  Step (III) is a step of stretching the gel-like molding in at least one direction (primary stretching) and drying the solvent to obtain a stretched product of the gel-like molding. The primary stretching step of step (III) is preferably biaxial stretching, and sequential biaxial stretching in which longitudinal stretching and lateral stretching are separately performed, simultaneous biaxial stretching in which longitudinal stretching and lateral stretching are simultaneously performed, and both methods are also preferable. It is possible to use. From the viewpoint of controlling the blood cell separation performance of the microporous polyolefin membrane, the draw ratio (product of longitudinal draw ratio and transverse draw ratio) of primary drawing is preferably 1.1 to 3 times, and the temperature at the time of drawing is 75 ° C. Is preferred. The drying step of step (III) is carried out without particular limitation as long as the gel-like molding is not deformed, but it is particularly preferable to be carried out at 60 ° C. or less.

  The drying step may be performed simultaneously with the primary stretching or may be performed stepwise. For example, primary stretching may be performed while predrying, and then drying treatment (main drying) may be performed to be subjected to secondary stretching in step (IV), or primary stretching may be performed between predrying and main drying. And may be subjected to secondary stretching in step (IV). Stretching can be performed in a state in which drying is controlled and the solvent is left in a suitable state.

  Step (IV) is a step of drawing the stretched product in a gel-like form in at least one direction (secondary drawing). Here, the secondary stretching step of the step (IV) is preferably biaxial stretching, sequential biaxial stretching in which longitudinal stretching and lateral stretching are performed separately, simultaneous biaxial stretching in which longitudinal stretching and lateral stretching are simultaneously performed, any of which The method can also be suitably used. In addition, a method of stretching in the longitudinal direction a plurality of times and then stretching in the transverse direction, a method of stretching in the longitudinal direction and stretching in the transverse direction a plurality of times, and after successive biaxial stretching, one or more times in the longitudinal direction and / or transverse direction The method of stretching in a cycle is also preferred.

  The draw ratio (the product of the longitudinal draw ratio and the transverse draw ratio) of the secondary drawing is preferably 10 to 65 times, more preferably 15 to 55 times, from the viewpoint of controlling the blood cell separation performance of the microporous polyolefin membrane. is there. When the draw ratio is increased, the frequency of occurrence of cutting tends to increase in the formation of the microporous polyethylene membrane. In addition, when the draw ratio is lowered, thickness unevenness tends to be large. Stretching is carried out after the solvent is removed, but drying can also be controlled to leave the solvent in a suitable state. The stretching temperature is preferably 90 to 135 ° C., and more preferably 90 to 125 ° C., from the viewpoint of controlling the blood cell separation performance of the microporous polyolefin membrane.

  A heat setting process may be performed subsequent to the secondary stretching step of (IV). The heat setting temperature is preferably 120 to 160 ° C., and more preferably 125 to 150 ° C., from the viewpoint of controlling the blood cell separation performance of the microporous polyolefin membrane. When the heat setting temperature is increased, the frequency of occurrence of cutting increases in the formation of the polyethylene microporous membrane.

  This process makes it possible to produce a microporous polyethylene membrane having a highly porous structure.

(Hydrophilization treatment)
In one embodiment of the present invention, the hydrophilic treatment method is at least one method selected from the group consisting of corona discharge treatment, plasma treatment, UV ozone treatment, coating of hydrophilic material, and graft polymerization of hydrophilic monomer. Is preferred. In order to satisfy the hydrophilic effect up to the inside of the pores, plasma treatment, coating of a hydrophilic material, and graft polymerization of a hydrophilic monomer are preferable. The hydrophilic material includes cellulose, polyvinyl alcohol, polyethylene-polyvinyl alcohol copolymer, polyurethane, polyacrylamide and the like. Examples of hydrophilic monomers include acrylic acid, methacrylic acid, vinyl alcohol, N-vinyl-2-pyrrolidone, and vinyl sulfonic acid.

[Second base material]
In one embodiment of the present invention, the second base material is overlapped and connected to at least a part of the first base material, and when the average flow pore diameter of the first base material is x ₁ , the above formula (1) And a hydrophilic polyolefin microporous membrane having an average flow pore diameter x ₂ satisfying The definitions of "microporous membrane" and "hydrophilic" are the same as in the first substrate. As an aspect which superimposes and connects a 2nd substrate to at least one copy of the 1st substrate, it is the surface which has the largest surface area of the 1st substrate 10 in hemocyte separation membrane 100, as illustrated in FIG. A mode in which the first base and the second base are overlapped and connected such that one side of the second base 11 and one side of the surface having the largest surface area of the second base 11 have the same length and become parallel. Including. In addition, as shown in FIG. 2, in the blood cell separation membrane 200, those in which the lengths in the width direction of the first base material 20 and the second base material 21 are different may be overlapped. However, the shapes and connection modes of the first base and the second base are not limited to these, and for example, an aspect in which the first base and the second base overlap over the entire surface, etc. Including. Further, in the present disclosure, the state in which the substrates are “connected” may be a state in which two substrates are simply arranged so as to overlap each other (not bonded), or an adhesive or a hot agent. The substrates may be adhered to each other by pressing. In the present disclosure, in the immunochromatography, the side to which the sample is added is upstream, or the upstream side, and the direction in which the chromatograph is developed is downstream or downstream. In the immunochromatographic strip according to an embodiment of the present invention, the second substrate is connected to the upstream side of the first substrate.

(Average flow pore size)
It is important that the second base material have an average flow pore size x ₂ satisfying the above equation (1) when the average flow pore size of the first substrate is x ₁ . Such a second substrate separates the majority of blood cells from whole blood and improves the spread uniformity of plasma in the first substrate. Most blood cells can be separated because the pore diameter x2 of the _second substrate is larger than the pore diameter x1 of the _first substrate. In such a viewpoint, the pore diameter x2 of the _second substrate is preferably larger by 0.01 μm or more than the pore diameter x1 of the _first substrate by 0.1 μm or more, more preferably by 1 μm or more. Is more preferable, and 2.2 μm or more is particularly preferable. On the other hand, when the pore diameter x2 of the _second base material is less than 5 μm, the separation performance of blood cells is improved. In such a viewpoint, the pore diameter x2 of the _second base material is preferably 4.5 μm or less, and more preferably 4 μm or less. In addition, the measuring method of an average flow hole diameter is the same as a 1st base material.

(Thickness)
In one embodiment of the present invention, the film thickness of the second substrate is preferably 10 to 190 μm, more preferably 20 to 170 μm, and particularly preferably 30 to 150 μm. When the film thickness of the second base material is 190 μm or less, it is preferable because the bed volume is small and a large amount of plasma can be obtained. On the other hand, when the film thickness of a 2nd base material is 10 micrometers or more, sufficient mechanical strength is easy to be obtained and the handling property at the time of processing of a polyolefin fine porous film also becomes favorable, and is preferable.

(Porosity)
In one embodiment of the present invention, the porosity of the second substrate is preferably 50 to 95%, more preferably 60% to 95%. When the porosity of the second base material is 50% or more, it is preferable because the spreadability of the liquid is good. On the other hand, when the porosity of the second base material is 95% or less, the mechanical strength of the film is favorable, which is preferable in that the handling property is also improved. In addition, the measuring method of a porosity is the same as a 1st base material.

(Gare value per 1 micrometer thickness)
In one embodiment of the present invention, the Gurley value (100 cc air permeation time) per micrometer thickness of the second substrate is preferably 0.001 to 0.01 second / 100 cc / μm, and 0.001 It is further preferable that it is -0.006 second / 100 cc / μm, and particularly preferable that it is 0.001 to 0.004 second / 100 cc / μm. When the Gurley value is 0.01 second / 100 cc / μm or less, it is preferable in that the spreadability of the solution is good. On the other hand, when the Gurley value is 0.001 sec / 100 cc / μm or more, the mechanical strength of the film is improved, and the handling property is also improved, which is preferable.

(Contact angle)
In one embodiment of the present invention, when the second base material is placed on a horizontal surface and water is dropped on the surface, it is preferable that the surface contact angle of the droplet after 1 second is 0 to 30 degrees And 0 to 20 degrees. When the contact angle after 1 second is 30 degrees or less, it is preferable in that the spreadability of the liquid is good.

  The second base material is the same as the first base material in the polyolefin used, the method for producing the microporous polyolefin membrane, and the hydrophilization treatment.

[Third base material]
In the blood cell separation membrane according to one embodiment of the present invention, it is preferable to further include a third base material that is connected to at least a part of the second base material and is made of a hydrophilic fiber-based sheet. The aspect in which the third base material is overlapped and connected to at least a part of the second base is the same as the aspect in which the second base material is overlapped and connected to at least a part of the first base. As an example, a blood cell separation membrane 300 provided with a third substrate is shown in FIG. The blood cell separation membrane 300 includes a first base 30, a second base 31, and a third base 32. In the immunochromatographic strip of one embodiment of the present invention, the third substrate is connected to the upstream side of the second substrate. The third substrate can remove coarse components that cause clogging in the second substrate, and can reduce clogging of the second substrate. The hydrophilic fiber-based sheet is a sheet comprising fibers such as non-woven fabric, paper, woven fabric and the like consisting of hydrophilic fibers or hydrophobic fibers subjected to hydrophilization treatment, and non-woven fabric is particularly preferable. Examples of hydrophilic fibers include cellulose, PVA, CMC, cotton, hemp and the like. The hydrophobic fiber includes glass fiber, PET, polyester, nylon and the like. With regard to the hydrophilization treatment, the same method as that of the first substrate can be used.

(Thickness)
In one embodiment of the present invention, the film thickness of the third substrate is preferably 100 to 500 μm, more preferably 150 to 400 μm, and particularly preferably 200 to 300 μm. When the film thickness of the third substrate is 500 μm or less, it is preferable because a small bed volume can be obtained and a large amount of plasma can be obtained. On the other hand, when the film thickness is 100 μm or more, sufficient mechanical strength is easily obtained, and the handling property at the time of processing and the like is also favorable, which is preferable.

(Porosity)
In one embodiment of the present invention, the porosity of the third substrate is preferably 50 to 95%, more preferably 60% to 93%, and particularly preferably 70 to 90%. When the porosity is 50% or more, it is preferable because the spreadability of the liquid is good. On the other hand, when the porosity is 95% or less, it is preferable in that the mechanical strength of the film is improved and the handling property is also improved. In addition, the measuring method of a porosity is the same as the method shown by the following Example.

(Weight)
In one embodiment of the present invention, the basis weight of the third base is preferably from 30 to 80 g / ^{m 2,} more preferably 40~70g / ^{m 2,} particularly preferably 50~60g / ^{m 2.} When the fabric weight is 80 g / m ² or less, the spreadability of the solution is good, which is preferable. On the other hand, when the fabric weight is 30 g / m ² or more, the mechanical strength of the film is good and the handling property is also improved, which is preferable.

[Immunochromatographic strip]
The immunochromatographic strip according to an embodiment of the present invention is an immunochromatographic strip for testing a liquid sample that may contain a substance to be detected, and for immunochromatography according to an embodiment of the present invention Includes blood cell separation membrane. An immunochromatographic strip according to an embodiment of the present invention comprises, in addition to a blood cell separation membrane, a sample pad for adding a sample, and a conjugate pad containing a labeling substance that specifically binds to the substance to be detected; The chromatography medium which fixed the detection reagent which specifically binds with the to-be-detected substance may be provided. The width and shape of the strip are not particularly limited, and there is no problem as long as the width and shape are easy to operate.

  Specifically, FIG. 4 shows the configuration of the immunochromatographic strip A according to an embodiment of the present invention. The immunochromatographic strip A has a sample pad 12 to which a sample is added from the upstream toward the downstream in the developing direction (the direction indicated by arrow X in FIG. 4), and a blood cell separation membrane 100 for separating blood cell components from whole blood sample. (Including the second substrate 11 and the first substrate 10), the conjugate pad 13 containing the labeling substance, the chromatography medium 14 on which the detection reagent specifically binding to the substance to be detected is immobilized, and An absorbent pad 15 for absorbing a sample is fixed in this order on a long support plate 16 made of plastic or the like. The chromatography medium 14 is provided with a detection unit 17. In FIG. 4 to FIG. 6, the region of the detection unit 17 is visibly illustrated by a black line.

  The method of using the immunochromatographic strip A will be described with reference to FIGS. 5 and 6. 5 and 6 schematically show cross sections in the thickness direction of the immunochromatographic strip A. FIG. In the drawings, the same reference numerals are used for the same members. First, when a sample possibly containing a substance to be detected is dropped on the sample pad 12, blood cell components are appropriately removed by the blood cell separation membrane 100 for separating blood cells and extracting plasma, and then to the conjugate pad 13. And the sample moves. Since the conjugate pad 13 contains a labeling substance using an antibody capable of binding to the substance to be detected in the sample, the substance to be detected and the labeling substance are bound in the conjugate pad 13 to form a complex, The sample containing this complex moves to the upstream side of the chromatography medium 14 (state of (a) of FIG. 6). In the chromatography medium 14, the sample moves toward the detection unit 17, and when the sample contains a substance to be detected, in the detection section 17, the complex of the substance to be detected and the labeling substance specifically corresponds to the detection reagent. By binding, the labeled substance is concentrated in the detection unit 17 (state of (b) in FIG. 6). Thus, the presence of the substance to be detected in the sample can be analyzed qualitatively and quantitatively using visual inspection or an appropriate device. Thereafter, excess sample is absorbed by the absorbent pad 15.

  Hereinafter, each composition of the sample that can be analyzed by immunochromatography and the strip for immunochromatography will be described in detail.

(sample)
In the present invention, the sample that can be analyzed by the immunochromatographic strip is not particularly limited as long as it is a sample that may contain blood cells and a substance to be detected, and for example, biological samples, in particular In particular human body fluids (eg blood, serum, plasma, spinal fluid, tears, sweat, urine, pus, runny nose, or sputum) or excrements (eg feces), organs, tissues, mucous membranes or skin, Examples include squeezed samples (swabs) and mouthwashes that are considered to contain.

  The substance to be detected is not particularly limited as long as it has a substance that specifically binds thereto, and proteins, peptides, nucleic acids, sugars (in particular, the sugar part of glycoprotein, the sugar part of glycolipid, etc.), complex sugar Quality etc. can be illustrated. “Specifically binding” means binding based on the affinity possessed by a biomolecule. Such affinity-based binding includes binding between antigen and antibody, binding between sugar and lectin, binding between hormone and receptor, binding between enzyme and inhibitor, complementary nucleic acids, nucleic acid and nucleic acid binding protein And the like. Therefore, when the substance to be detected has antigenicity, examples of substances that specifically bind to the substance to be detected include polyclonal antibodies or monoclonal antibodies. When the substance to be detected is a sugar, a lectin protein can also be exemplified as the substance specifically binding to the substance to be detected. Specific substances to be detected include, for example, carcinoembryonic antigen (CEA), HER2 protein, prostate specific antigen (PSA), CA19-9, α-fetoprotein (AFP), immunosuppressive acid protein (IPA), CA15- 3, CA 125, estrogen receptor, progesterone receptor, fecal occult blood, troponin I, troponin T, CK-MB, CRP, human chorionic gonadotropin (hCG), luteinizing hormone (LH), follicle stimulating hormone (FSH), syphilis antibody, Examples include, but are not limited to, influenza virus, human hemoglobin, chlamydia antigen, group A beta-streptococcal antigen, HBs antibody, HBs antigen, rotavirus, adenovirus, albumin, glycated albumin and the like.

  In immunochromatography, (i) when the sample is used as it is, (ii) when it is used as an extract obtained by extracting the sample using an appropriate solvent for extraction, (iii) the sample or the extract is suitable When used as a diluted solution obtained by dilution with a diluent, (iv) when used as a concentrated solution obtained by concentrating the sample or extract by an appropriate method, (v) above (i) to (iv) Any of the liquids may contain the labeling substance and the labeling substance and the substance to be detected may be complexed in advance. As a solvent for extraction or a diluent, a solvent (for example, water, physiological saline, buffer or the like) used in a conventional immunological analysis can be used.

  In the present invention, a developing solution may be used if necessary. The developing solution is a liquid that constitutes the mobile phase in immunochromatography, and moves on the chromatography medium along with the sample containing the substance to be detected. Any such developing solution may be used. The developing solution is not limited to the case where it is developed with the sample, and may be configured to be developed from the flow path different from the sample and finally connected to the chromatography medium.

(Sample pad)
For the sample pad, use a non-woven fabric, a paper-like body, a woven fabric or a microporous film consisting of one or two or more of various fibers such as cellulose, glass, polyurethane, polyacetate, cellulose acetate, nylon, polyolefin and cotton. But not limited thereto. The sample pad not only receives the sample containing the added substance to be detected, but also serves to filter insoluble particles and the like in the sample. In addition, in order to prevent nonspecific adsorption of the substance to be detected in the sample on the material of the sample pad during inspection and to reduce the inspection accuracy, the material constituting the sample pad is previously prevented from nonspecific adsorption. You may process and use. The sample pad can be used not only as a single sheet, but also in combination with other sheets such as non-woven fabric as needed.

(Hemocyte separation membrane)
An immunochromatographic blood cell separation membrane in one embodiment and another embodiment of the present invention will be described. For example, the separation membrane 100 shown in FIG. 1 has a first base material 10 and a second base material 11 connected to the upstream side. The separation membrane 200 shown in FIG. 2 has a first base material 20 and a second base material 21 connected to the upstream side. Further, the separation membrane 300 shown in FIG. 3 includes the first base material 30, the second base material 31 connected to the upstream side, and the third base 31 connected to the upstream side. And the substrate 32 of

  The length in the width direction of the overlapping portion of the first base and the second base (the elongated connecting portion of the first base and the second base in FIGS. 1, 2 and 3) The length in the width direction, that is, the length L1 of the portion where the first base and the second base overlap in the developing direction is preferably 1 mm to 5 mm. When the length of the connection portion is 1 mm or more, the expandability of plasma is improved. From such a viewpoint, the length of the connection portion is more preferably 2 mm or more. If the length of the connection portion is 5 mm or less, the required amount of sample may be small. From such a viewpoint, the length of the connection portion is more preferably 4 mm or less.

  Length in the width direction of the overlapping portion of the second base and the third base (length in the width direction of the elongated connecting part of the second base and the third base in FIG. 3; That is, the length L2 of the portion where the second base and the third base overlap in the developing direction is preferably 1 mm to 5 mm. When the length of the connection portion is 1 mm or more, the expandability of plasma is improved. From such a viewpoint, the length of the connection portion is more preferably 2 mm or more. If the length of the connection portion is 5 mm or less, the required amount of sample may be small. From such a viewpoint, the length of the connection portion is more preferably 4 mm or less.

(Conjugate pad)
The conjugate pad may be, for example, a non-woven fabric, a paper-like body, a woven fabric or a microporous membrane consisting of one or two or more of various fibers such as cellulose, glass, polyurethane, polyacetate, cellulose acetate, nylon, polyolefin and cotton. Although it can be used, it is not limited to these. The conjugate pad can be made by impregnating a fixed amount of a suspension containing a labeling substance and drying it.

(Labeled substance)
In one embodiment of the present invention, the labeling substance has a binding part that specifically binds to the substance to be detected, and a labeling part for determination. Although an insoluble carrier, an enzyme, etc. can be used as a label | marker part, An insoluble carrier is preferable at the point which is easy to judge by visual observation. When an insoluble carrier is used, it can be prepared by sensitizing the binding site to the insoluble carrier. The bonding portion may be appropriately selected depending on the target substance to be detected.

  As the insoluble carrier, colloidal metal particles such as gold, silver and platinum, colloidal metal oxide particles such as iron oxide, colloidal nonmetal particles such as sulfur, latex particles made of synthetic polymers, and others are used. be able to. In particular, gold colloids are preferred because they are easy to detect.

  The insoluble carrier is preferably colored in order to facilitate visual judgment. The colloidal metal particles and the colloidal metal oxide particles themselves exhibit a specific natural color depending on the particle size, and the color can be used as a label.

  Examples of colloidal metal particles and colloidal metal oxide particles include colloidal gold particles, colloidal silver particles, colloidal platinum particles, colloidal iron oxide particles, colloidal aluminum hydroxide particles and the like. In particular, colloidal gold particles are preferably red and colloidal silver particles are preferably yellow in that colloidal gold particles and colloidal silver particles have suitable particle sizes. The average particle diameter of these colloidal metal particles is more preferably in the range of 1 to 500 nm, in particular 10 nm to 150 nm where a strong color tone can be obtained, and more preferably 20 to 100 nm.

  When colloidal gold particles, for example, are used as colloidal metal particles, commercially available particles may be used. Alternatively, colloidal gold particles can be prepared in a conventional manner, for example by reduction of chloroauric acid with sodium citrate.

  As a method of sensitizing the binding portion to the colloidal metal particles, known methods such as physical adsorption and chemical bonding can be used. For example, a labeled substance obtained by sensitizing an antibody to colloidal gold particles is physically adsorbed by adding an antibody to a solution in which gold particles are dispersed in a colloidal state, and then a bovine serum albumin solution is added to cause no antibody binding. Prepared by blocking the particle surface.

(Chromatography medium)
The chromatography medium comprises a chromatography medium substrate, and a detection unit formed on at least a part of the substrate and on which a detection reagent that specifically binds to a substance to be detected is immobilized. . The detection unit is a region in which a detection reagent that specifically binds to the substance to be detected is immobilized. Specifically, as shown in FIG. 4, it is preferable that the detection unit 17 be formed linearly along the width direction of the base material at an arbitrary position of the base material for chromatography media. For example, it may be a circular spot, a number, a character, or a symbol such as + or-. When there are a plurality of substances to be detected, detection reagents corresponding to each may be immobilized to form a plurality of detection units on the chromatography medium.

  Further, on the downstream side of the detection unit, a control unit may be formed on the chromatography medium, which is a region in which a control substance that specifically binds to the labeling substance is immobilized. When the control unit is provided, when the sample passes through the detection unit and then moves to the control unit, the labeling substance is specifically bound to the control substance, whereby the labeling substance is concentrated in the control unit. As a result, it is possible to confirm that the sample has moved to the control unit visually or using an appropriate device, and to know whether the inspection has been completed.

  The detection reagent used in one embodiment of the present invention is a substance that specifically binds to a substance to be detected, such as an antibody or an antigen. As a method of immobilizing the detection reagent on the substrate, a method of directly immobilizing the detection reagent on the substrate by physical or chemical means, and a method of physically or chemically binding the detection reagent to microparticles such as latex particles Any of the indirect immobilization methods for immobilizing the microparticles on a substrate may be used.

  As a direct immobilization method, physical adsorption may be used, or covalent bonding may be used. In covalent bonding, cyanogen bromide, glutaraldehyde, carbodiimide and the like are generally used to activate the chromatography medium, but any method can be used. As a method of immobilizing indirectly, there is a method of immobilizing on a chromatography medium after binding a detection reagent to insoluble microparticles. The particle size of the insoluble fine particles can be selected to be a size that can be trapped in the chromatography medium but can not move, and is preferably fine particles having an average particle size of about 5 μm or less. As these particles, various ones used for an antigen-antibody reaction are known, and these known particles can be used in one embodiment of the present invention. For example, organic polymers such as organic polymer latex particles obtained by the emulsion polymerization method of polystyrene, styrene-butadiene copolymer, styrene-methacrylic acid copolymer, polyglycidyl methacrylate, acrolein-ethylene glycol dimethacrylate copolymer, etc. Fine particles of substances, fine particles of gelatin, bentonite, agarose, cross-linked dextran, etc., inorganic particles of silica, silica-alumina, inorganic oxide such as alumina or inorganic oxide in which a functional group is introduced to the inorganic oxide by silane coupling treatment etc. . In one embodiment of the present invention, direct immobilization is preferable in terms of ease of sensitivity adjustment and the like. In addition, various methods can be used to immobilize the detection reagent on the chromatography medium. For example, various techniques such as a microsyringe, a pen with a control pump, ink jet printing, etc. can be used.

  After immobilizing the detection reagent, the chromatography medium can be subjected to blocking treatment by a known method, if necessary, in order to prevent the decrease in analysis accuracy due to nonspecific adsorption. In general, proteins such as bovine serum albumin, skimmed milk, casein and gelatin are preferably used for blocking treatment. After such blocking treatment, if necessary, one or two or more surfactants such as Tween 20, Triton X-100, SDS (sodium dodecyl sulfate), SDBS (sodium dodecyl benzene sulfonate), etc. may be combined and washed. .

(Absorbent pad)
The absorbent pad is for absorbing the finally drained sample. As such an absorbent pad, for example, a cellulose filter paper, a non-woven fabric, a cloth, a water-absorbent material such as cellulose acetate is used. The spreading speed of the added sample (the leading edge of the flowing sample) after it reaches the absorbent pad varies depending on the material, size, etc. of the absorbent pad. You can set the speed that suits you.

  Applications of immunochromatography include diagnosis of infectious diseases such as influenza, hepatitis B and food poisoning, diagnosis of pregnancy, various marker diagnoses such as myocardial infarction and the like.

  EXAMPLES Examples, comparative examples and various measurement methods of one embodiment of the present invention will be described below, but the present invention is not limited to these examples.

[Measuring method]
Hereinafter, the measuring method used in the Example regarding one Embodiment of this invention is demonstrated.

(Film thickness)
The film thickness of the sample was determined by measuring at 20 points with a contact-type film thickness meter (manufactured by Mitutoyo Co., Ltd.) and averaging these. Here, a cylindrical terminal whose bottom surface has a diameter of 0.5 cm was used. The measurement pressure was 0.1 N.

(Porosity)
The constituent materials consist of a, b, c ... n, the weight of the constituent materials is Wa, Wb, Wc ... Wn (g / cm ² ), and the true density of each is xa, xb, xc ... xn ( The porosity 膜厚 (%) is obtained from the following equation (3), where t (cm) is the film thickness of the layer of interest in g / cm ³ ).
ε = {1- (Wa / xa + Wb / xb + Wc / xc +... + Wn / xn) / t} × 100 Equation (3)

(Gare value)
The 100 cc air permeation time τ per 1 micrometer thickness was determined as follows. The air permeation time (sec / 100 cc) T of a sample having an area of 642 mm ² was measured according to JIS P8117. From the above air permeation time and film thickness, 100 cc air permeation time per 1 micrometer thickness was determined by the following equation (4).
τ = T / t equation (4)
T: Air permeation time measured according to JIS P8117 (sec / 100 cc)
t: Film thickness (μm)

(Average flow pore size)
The average flow pore diameter of the microporous polyolefin membrane was measured using a PPM palm porometer (model: CFP-1200-AEXL), and using a PMI galwick (surface tension = 15.9 dynes / cm) as the immersion liquid. The average flow pore size (μm) was determined based on the half dry method specified in ASTM E1294-89. The measurement temperature was 25 ° C., and the measurement pressure was changed in the range of 0 to 150 psi.

(Contact angle)
The static contact angle was measured using a fully automatic contact angle meter DMo-701FE manufactured by Kyowa Interface Science Co., Ltd. and an Interface Measurement and Analysis System FAMAS as a measurement device. 2 μL of pure water was dropped onto the sample of the microporous polyolefin membrane subjected to the hydrophilization treatment, and the contact angle after dropping for 1 second at 24 ° C. and 60% relative humidity in the air under atmospheric pressure was measured. For the measurement, a syringe using an SUS (stainless steel) 18 G needle was used.

(Confirmation of blood cell separation performance)
The blood cell separation performance of the separation membranes prepared in the following examples and comparative examples was confirmed as follows.

Each substrate was fixed on a plastic plate with double-sided tape, and a polystyrene tube cut at about 1 cm was placed on the most upstream substrate. The substrate connects the second substrate on the upstream side of the first substrate and connects the second substrate, and in the case of including the third substrate, the third group on the further upstream side of the second substrate The materials were stacked and connected. About 200 μL of pig fresh blood was placed in a tube and spread on a membrane. The evaluation criteria are A, B, C and D below.
A: Blood cells are separated at the interface between the first substrate and the second substrate, and only plasma is developed on the first substrate.
B: Blood spreads to the first substrate and blood cells are separated in the first substrate.
C: Blood develops to the first substrate, but blood cells are not separated.
D: Blood does not spread to the first substrate.

(Confirmation of hemolysis)
A test similar to the confirmation of the blood cell separation performance was performed, and the presence or absence of hemolysis was visually determined on the downstream side of the first substrate. The evaluation criteria are A, B, C and D below.
A: completely without hemolysis B: very slightly appear red but practically no problem C: a little hemolysis is confirmed, practically insufficient D: sharp hemolysis

(Confirmation of plasma volume)
The same test as confirmation of the blood cell separation performance was performed, and the plasma volume obtained from the area of the plasma part after separation was evaluated. As an evaluation criterion, assuming that the area of the plasma part of Comparative Example 1 is 100, the area ratio obtained by dividing the area of the plasma part in each Example and Comparative Example by the area of the plasma part of Comparative Example 1 is obtained. It evaluated by A, B, C, D.
A: area ratio of 200% or more B: area ratio of 150% to 200% C: area ratio of 100% to 150% D: area ratio of less than 100%

(Separation time)
A test similar to the confirmation of the blood cell separation performance was performed, and the time until the plasma moved through the substrate and stopped was measured visually. As the evaluation criteria, when the separation time of Comparative Example 1 is 100, the separation time in each Example and Comparative Example is divided by the separation time of Comparative Example 1 to obtain the separation time ratio, and the following A, B, It evaluated by C and D.
A: Separation time ratio is less than 100% B: Separation time ratio is 100% or more and less than 150% C: Separation time ratio is 150% or more and less than 200% D: Separation time ratio is 200% or more

(Eluting resistance)
After the substrate was immersed in methylene chloride for a predetermined time, the substrate was removed, and the weight of the methylene chloride solution after immersion was measured. Separately from this, fresh methylene chloride having the same weight as the measured weight described above was prepared, and after each solvent was completely removed by evaporating the methylene chloride from each solvent (drying), each weight was measured. Based on the weight increment after completely removing fresh methylene chloride, the ratio of the weight increment after drying the methylene chloride solution after immersion of the microporous polyolefin membrane was calculated. The evaluation criteria are A, B, C and D below.
A: 1.01 times or less B: 1.01 times or more, 1.05 times or less C: 1.05 times or more D: Measurement impossible

Example 1
The first substrate was produced as follows. As a polyolefin resin, a polyolefin composition was used in which 3.8 parts by weight of ultrahigh molecular weight polyethylene having a weight average molecular weight of 4,600,000 and 21.2 parts by weight of high density polyethylene having a weight average molecular weight of 560,000 were mixed. A polyethylene solution was prepared by mixing with decalin (decahydronaphthalene) such that the concentration of the total polyethylene resin was 25% by weight.

  The polyethylene solution was extruded into a sheet at a temperature of 155 ° C. from the die, and then the extrudate was cooled in a water bath to produce a gel-like sheet.

  The gel-like sheet is subjected to preliminary drying for 10 minutes in a temperature atmosphere of 70 ° C., and then subjected to primary stretching at 1.2 times in the longitudinal direction, and then this drying is carried out for 5 minutes in a temperature atmosphere of 57 ° C. Conducted to make a base tape (less than 1% residual solvent). After the main drying is completed, the base tape is stretched at a temperature of 90 ° C. at a magnification of 4.0 times in the longitudinal direction as secondary stretching, and subsequently stretched at a temperature of 125 ° C. at a magnification of 9 times in the width direction. Immediately heat treatment (heat setting) was performed at 144 ° C. to obtain a biaxially stretched polyethylene microporous membrane. The polyethylene microporous membrane thus obtained was subjected to plasma treatment as a hydrophilization treatment.

  The second substrate was produced as follows. As a polyolefin resin, a polyolefin composition was used in which 1.3 parts by weight of ultrahigh molecular weight polyethylene having a weight average molecular weight of 4,600,000 and 23.7 parts by weight of high density polyethylene having a weight average molecular weight of 560,000 were mixed. A polyethylene solution was prepared by mixing with decalin (decahydronaphthalene) such that the concentration of the total polyethylene resin was 25% by weight.

  The polyethylene solution was extruded into a sheet at a temperature of 155 ° C. from the die, and then the extrudate was cooled in a water bath to produce a gel-like sheet.

  The gel-like sheet is pre-dried for 10 minutes in a temperature atmosphere of 70 ° C., and then primarily stretched in the longitudinal direction by 1.4 times, and then the main drying is performed for 5 minutes in a temperature atmosphere of 57 ° C. Conducted to make a base tape (less than 1% residual solvent). After the main drying is completed, the base tape is stretched in the longitudinal direction at a temperature of 100 ° C. at a magnification of 3.0 times in the longitudinal direction as secondary stretching, and subsequently in a width direction at a temperature of 125 ° C. at a magnification of 9 times Heat treatment (heat setting) was immediately performed at 127 ° C. to obtain a biaxially stretched polyethylene microporous membrane. The polyethylene microporous membrane thus obtained was subjected to plasma treatment as a hydrophilization treatment.

  The hemochromatus separation membrane for immunochromatography in one embodiment of the present invention is manufactured by laminating so that the length in the short direction of the overlapping portion of the first substrate and the second substrate is 1 mm (without adhesion). did. The physical property values and the evaluation results of this separation membrane are shown in Table 1. The same is also shown in Table 1 for the following examples and comparative examples.

Example 2
As a first substrate, a polyolefin composition was used in which 5.8 parts by weight of ultrahigh molecular weight polyethylene having a weight average molecular weight of 4,600,000 and 17.2 parts by weight of high density polyethylene having a weight average molecular weight of 560,000 were mixed. . A polyethylene solution was prepared by mixing with decalin (decahydronaphthalene) such that the concentration of the total polyethylene resin was 23% by weight.

  The polyethylene solution was extruded into a sheet at a temperature of 155 ° C. from the die, and then the extrudate was cooled in a water bath to produce a gel-like sheet.

  The gel-like sheet is subjected to preliminary drying for 10 minutes in a temperature atmosphere of 70 ° C., and then subjected to primary stretching at 1.8 times in the longitudinal direction, and then main drying is carried out for 5 minutes in a temperature atmosphere of 57 ° C. Conducted to make a base tape (less than 1% residual solvent). After the main drying is completed, the base tape is stretched in the longitudinal direction at a temperature of 90 ° C. at a magnification of 3.0 times in the longitudinal direction as secondary stretching, and subsequently stretched in the width direction at a temperature of 125 ° C. at a magnification of 9.0 times. Then, heat treatment (heat setting) was performed immediately at 144 ° C. to obtain a biaxially stretched polyethylene microporous membrane. The polyethylene microporous membrane thus obtained was subjected to plasma treatment as a hydrophilization treatment.

  An immunochromatographic blood cell separation membrane of one embodiment of the present invention was produced in the same manner as in Example 1 except that such a first base material was used.

[Example 3]
As a first substrate, a polyolefin composition was used in which 7.5 parts by weight of ultrahigh molecular weight polyethylene having a weight average molecular weight of 4,600,000 and 17.5 parts by weight of high density polyethylene having a weight average molecular weight of 560,000 were mixed. . A polyethylene solution was prepared by mixing with decalin (decahydronaphthalene) such that the concentration of the total polyethylene resin was 25% by weight.

  The polyethylene solution was extruded into a sheet at a temperature of 155 ° C. from the die, and then the extrudate was cooled in a water bath to produce a gel-like sheet.

  The gel-like sheet is predried for 10 minutes in a temperature atmosphere of 70 ° C., and then primarily stretched in the longitudinal direction by 1.6 times, and then this drying is carried out for 5 minutes in a temperature atmosphere of 105 ° C. Conducted to make a base tape (less than 1% residual solvent). After the main drying is completed, the base tape is stretched at a temperature of 90 ° C. at a magnification of 4.5 times in the longitudinal direction as secondary stretching, and subsequently stretched at a temperature of 125 ° C. at a magnification of 9.0 times in the width direction. Then, heat treatment (heat setting) was performed immediately at 147 ° C. to obtain a biaxially stretched polyethylene microporous membrane. The polyethylene microporous membrane thus obtained was subjected to plasma treatment as a hydrophilization treatment.

  An immunochromatographic blood cell separation membrane of one embodiment of the present invention was produced in the same manner as in Example 1 except that such a first base material was used.

Example 4
As a second substrate, a polyolefin composition was used in which 1.3 parts by weight of ultrahigh molecular weight polyethylene having a weight average molecular weight of 4.6 million and 23.7 parts by weight of high density polyethylene having a weight average molecular weight of 560,000 were used. . A polyethylene solution was prepared by mixing with decalin (decahydronaphthalene) such that the concentration of the total polyethylene resin was 25% by weight.

  The polyethylene solution was extruded into a sheet at a temperature of 155 ° C. from the die, and then the extrudate was cooled in a water bath to produce a gel-like sheet.

  The gel-like sheet is pre-dried for 10 minutes in a temperature atmosphere of 70 ° C., and then primarily stretched in the longitudinal direction by 1.4 times, and then the main drying is performed for 5 minutes in a temperature atmosphere of 57 ° C. Conducted to make a base tape (less than 1% residual solvent). After the main drying is completed, the base tape is stretched in the longitudinal direction at a temperature of 90 ° C. at a magnification of 3.0 times in the longitudinal direction as secondary stretching, and subsequently stretched in the width direction at a temperature of 125 ° C. at a magnification of 9.0 times. Then, heat treatment (heat setting) was performed immediately at 145 ° C. to obtain a biaxially stretched polyethylene microporous membrane. The polyethylene microporous membrane thus obtained was subjected to plasma treatment as a hydrophilization treatment.

  An immunochromatographic separation membrane for immunochromatography according to an embodiment of the present invention was produced in the same manner as in Example 1 except that such a second base material was used.

[Example 5]
As a third substrate, a PET non-woven fabric was subjected to plasma treatment, and laminated so that the length in the short direction of the overlapping portion of the third substrate and the second substrate was 1 mm (no adhesion).

  An immunochromatographic separation membrane for immunochromatography according to an embodiment of the present invention was produced in the same manner as in Example 1 except that such a third base material was used.

[Example 6]
As a third base material, two types of PET nonwoven fabrics A and B having different average flow pore sizes are subjected to plasma treatment, and PET nonwoven fabric B is overlapped on the upstream side of PET nonwoven fabric A, and the length in the short direction of overlapping portions of each nonwoven fabric It laminated so that it might be set to 1 mm (no adhesion), and made this into the 3rd substrate. And it laminated | stacked so that the length of the transversal direction of the overlapping part of the nonwoven fabric A and a 2nd base material might be set to 1 mm (adhesion is absent).

  An immunochromatographic separation membrane for immunochromatography according to an embodiment of the present invention was produced in the same manner as in Example 1 except that such a third base material was used.

[Examples 7 to 8]
Blood cell separation for immunochromatography according to one embodiment of the present invention in the same manner as in Example 1 except that the length in the short direction of the overlapping portion of the first base and the second base is changed as shown in Table 1. A membrane was made.

Comparative Example 1
As the first and second substrates, a polyethylene microporous membrane with an average flow pore diameter of 8 μm, which was plasma-treated as a hydrophilization treatment, was used.

  An immunochromatographic blood cell separation membrane was produced in the same manner as in Example 1 except that such first and second base materials were used.

Comparative Example 2
Polyolefin composition in which 1.3 parts by weight of ultrahigh molecular weight polyethylene having a weight average molecular weight of 4.6 million and 23.7 parts by weight of high density polyethylene having a weight average molecular weight of 560,000 are mixed as the first and second substrates Was used. A polyethylene solution was prepared by mixing with decalin (decahydronaphthalene) such that the concentration of the total polyethylene resin was 25% by weight.

  The polyethylene solution was extruded into a sheet at a temperature of 155 ° C. from the die, and then the extrudate was cooled in a water bath to produce a gel-like sheet.

  The gel-like sheet is pre-dried for 10 minutes in a temperature atmosphere of 70 ° C., and then primarily stretched in the longitudinal direction by 1.4 times, and then the main drying is performed for 5 minutes in a temperature atmosphere of 57 ° C. Conducted to make a base tape (less than 1% residual solvent). After the main drying is completed, the base tape is stretched in the longitudinal direction at a temperature of 90 ° C. at a magnification of 3.0 times in the longitudinal direction as secondary stretching, and subsequently stretched in the width direction at a temperature of 125 ° C. at a magnification of 9.0 times. Then, heat treatment (heat setting) was performed immediately at 145 ° C. to obtain a biaxially stretched polyethylene microporous membrane. The polyethylene microporous membrane thus obtained was subjected to plasma treatment as a hydrophilization treatment.

  An immunochromatographic blood cell separation membrane was produced in the same manner as in Example 1 except that such first and second base materials were used.

Comparative Example 3
As the first substrate, a polyolefin composition was used in which 1.3 parts by weight of ultrahigh molecular weight polyethylene having a weight average molecular weight of 4.6 million and 23.7 parts by weight of high density polyethylene having a weight average molecular weight of 560,000 were used. . A polyethylene solution was prepared by mixing with decalin (decahydronaphthalene) such that the concentration of the total polyethylene resin was 25% by weight.

  The polyethylene solution was extruded into a sheet at a temperature of 155 ° C. from the die, and then the extrudate was cooled in a water bath to produce a gel-like sheet.

  The gel-like sheet is pre-dried for 10 minutes in a temperature atmosphere of 70 ° C., and then primarily stretched in the longitudinal direction by 1.4 times, and then the main drying is performed for 5 minutes in a temperature atmosphere of 57 ° C. Conducted to make a base tape (less than 1% residual solvent). After the main drying is completed, the base tape is stretched in the longitudinal direction at a temperature of 100 ° C. at a magnification of 3.0 times in the longitudinal direction as secondary stretching, and subsequently in a width direction at a temperature of 125 ° C. at a magnification of 9 times Heat treatment (heat setting) was immediately performed at 127 ° C. to obtain a biaxially stretched polyethylene microporous membrane. The polyethylene microporous membrane thus obtained was subjected to plasma treatment as a hydrophilization treatment.

  An immunochromatographic blood cell separation membrane was produced in the same manner as in Example 1 except that such a first base material was used.

Comparative Example 4
As the first substrate, a polyolefin composition was used in which 1.3 parts by weight of ultrahigh molecular weight polyethylene having a weight average molecular weight of 4.6 million and 23.7 parts by weight of high density polyethylene having a weight average molecular weight of 560,000 were used. . A polyethylene solution was prepared by mixing with decalin (decahydronaphthalene) such that the concentration of the total polyethylene resin was 25% by weight.

  The polyethylene solution was extruded into a sheet at a temperature of 155 ° C. from the die, and then the extrudate was cooled in a water bath to produce a gel-like sheet.

  The gel-like sheet is pre-dried for 10 minutes in a temperature atmosphere of 70 ° C., and then primarily stretched in the longitudinal direction by 1.2 times, and then the main drying is carried out for 5 minutes in a temperature atmosphere of 57 ° C. Conducted to make a base tape (less than 1% residual solvent). After the main drying is completed, the base tape is stretched in the longitudinal direction at a temperature of 100 ° C. at a magnification of 3.0 times in the longitudinal direction as secondary stretching, and subsequently in a width direction at a temperature of 125 ° C. at a magnification of 9 times Immediately heat treatment (heat setting) was performed at 145 ° C. to obtain a biaxially stretched polyethylene microporous membrane. The polyethylene microporous membrane thus obtained was subjected to plasma treatment as a hydrophilization treatment.

  An immunochromatographic blood cell separation membrane was produced in the same manner as in Example 1 except that such a first base material was used.

Comparative Example 5
As the first substrate, a polyolefin composition was used in which 1.3 parts by weight of ultrahigh molecular weight polyethylene having a weight average molecular weight of 4.6 million and 23.7 parts by weight of high density polyethylene having a weight average molecular weight of 560,000 were used. . A polyethylene solution was prepared by mixing with decalin (decahydronaphthalene) such that the concentration of the total polyethylene resin was 25% by weight.

  The polyethylene solution was extruded into a sheet at a temperature of 155 ° C. from the die, and then the extrudate was cooled in a water bath to produce a gel-like sheet.

  The gel-like sheet is pre-dried for 10 minutes in a temperature atmosphere of 70 ° C., and then primarily stretched in the longitudinal direction by 1.2 times, and then the main drying is carried out for 5 minutes in a temperature atmosphere of 57 ° C. Conducted to make a base tape (less than 1% residual solvent). After the main drying is completed, the base tape is stretched in the longitudinal direction at a temperature of 100 ° C. at a magnification of 3.0 times in the longitudinal direction as secondary stretching, and subsequently in a width direction at a temperature of 125 ° C. at a magnification of 9 times Immediately heat treatment (heat setting) was performed at 145 ° C. to obtain a biaxially stretched polyethylene microporous membrane. The polyethylene microporous membrane thus obtained was subjected to plasma treatment as a hydrophilization treatment.

  An immunochromatographic blood cell separation membrane was produced in the same manner as in Example 1 except that such a first base material was used.

Comparative Example 6
As a first substrate, a polyolefin composition was used in which 6.0 parts by weight of ultrahigh molecular weight polyethylene having a weight average molecular weight of 4,600,000 and 24.0 parts by weight of high density polyethylene having a weight average molecular weight of 560,000 were used. . A mixed solution of 67.5 parts by weight of liquid paraffin and 2.5 parts by weight of decalin (decahydronaphthalene) was mixed to give a total concentration of polyethylene resin of 30% by weight to prepare a polyethylene solution.

  The polyethylene solution was extruded into a sheet at a temperature of 155 ° C. from the die, and then the extrudate was cooled in a water bath to produce a gel-like sheet.

  The gel-like sheet is subjected to preliminary drying for 10 minutes in a temperature atmosphere of 70 ° C., and then subjected to primary stretching in the longitudinal direction by 1.0 times, followed by final drying for 5 minutes in a temperature atmosphere of 105 ° C. Conducted to make a base tape (less than 1% residual solvent). After the main drying is completed, the base tape is stretched in the longitudinal direction at a temperature of 100 ° C. at a magnification of 5.5 times in the longitudinal direction as secondary stretching, and subsequently stretched in the width direction at a temperature of 105 ° C. at a magnification of 10 times Immediately heat treatment (heat setting) was performed at 140 ° C. to obtain a biaxially stretched polyethylene microporous membrane. The polyethylene microporous membrane thus obtained was subjected to plasma treatment as a hydrophilization treatment.

  An immunochromatographic blood cell separation membrane was produced in the same manner as in Example 1 except that such a first base material was used.

Comparative Example 7
Glass fibers for immunochromatography were used as the second substrate.

  An immunochromatographic blood cell separation membrane was produced in the same manner as in Example 1 except that such a second base material was used.

Comparative Example 8
A hydrophilic non-woven fabric made of cellulose fibers was used as the second substrate.

  An immunochromatographic blood cell separation membrane was produced in the same manner as in Example 1 except that such a second base material was used.

Comparative Example 9
As a 2nd base material, PET nonwoven fabric which gave plasma processing as hydrophilization processing was used.

  An immunochromatographic blood cell separation membrane was produced in the same manner as in Example 1 except that such a second base material was used.

  The disclosure of Japanese Patent Application No. 2017-067891, filed March 30, 2017, is incorporated herein by reference in its entirety. All documents, patent applications, and technical standards described herein are as specific and individually as individual documents, patent applications, and technical standards are incorporated by reference. Incorporated herein by reference.

Claims (8)

A first base material comprising a hydrophilic polyolefin microporous membrane having an average flow pore size of more than 0.06 μm and less than 1 μm;
It has an average flow pore size x ₂ which is overlapped and connected to at least a part of the first base material, and satisfies the following formula (1) when the average flow pore size of the first base material is x ₁ and A second substrate comprising a hydrophilic polyolefin microporous membrane ,
A hemocyte separation membrane for immunochromatography , wherein the mean flow pore size of the first substrate and the second substrate is a mean flow pore size based on a half dry method defined in ASTM E1294-89 .
x ₁ <x ₂ <5 μm Formula (1)   The blood separation membrane for immunochromatography of Claim 1 whose contact angle of the surface 1 second after dripping is 0-30 degrees, when water is dripped at a said 1st base material.   The blood separation membrane for immunochromatography of Claim 1 or 2 whose contact angle of the surface 1 second after dripping is 0-30 degrees, when water is dripped at a said 2nd base material.   The blood cell separation for immunochromatography according to any one of claims 1 to 3, wherein the length in the short direction of the overlapping portion of the first base material and the second base material is 1 mm or more and 5 mm or less. film.   The immunochromatography according to any one of claims 1 to 4, further comprising: a third base material composed of a hydrophilic fiber-based sheet, being overlapped and connected to at least a part of the second base material. Blood cell separation membrane.   The blood cell separation membrane for immunochromatography according to claim 5, wherein the length in the short direction of the overlapping portion of the third base and the second base is 1 mm or more and 5 mm or less.   The blood cell separation for immunochromatography according to any one of claims 1 to 6, wherein the film thickness of the first base material is 1 μm or more and less than 150 μm, and the porosity is 50% or more and less than 95%. film.   An immunochromatographic strip comprising the hemochromatographic membrane for immunochromatography according to any one of claims 1 to 7.