Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
  • G01N33/48—Biological material, e.g. blood, urine; Haemocytometers
  • G01N33/50—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing
  • G01N33/58—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing involving labelled substances
  • G01N33/585—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing involving labelled substances with a particulate label, e.g. coloured latex
  • G01N33/587—Nanoparticles
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
  • G01N33/48—Biological material, e.g. blood, urine; Haemocytometers
  • G01N33/50—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing
  • G01N33/53—Immunoassay; Biospecific binding assay; Materials therefor
  • G01N33/543—Immunoassay; Biospecific binding assay; Materials therefor with an insoluble carrier for immobilising immunochemicals
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
  • G01N33/48—Biological material, e.g. blood, urine; Haemocytometers
  • G01N33/50—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing
  • G01N33/52—Use of compounds or compositions for colorimetric, spectrophotometric or fluorometric investigation, e.g. use of reagent paper and including single- and multilayer analytical elements
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
  • G01N33/48—Biological material, e.g. blood, urine; Haemocytometers
  • G01N33/50—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing
  • G01N33/53—Immunoassay; Biospecific binding assay; Materials therefor
  • G01N33/543—Immunoassay; Biospecific binding assay; Materials therefor with an insoluble carrier for immobilising immunochemicals
  • G01N33/544—Immunoassay; Biospecific binding assay; Materials therefor with an insoluble carrier for immobilising immunochemicals the carrier being organic
  • G01N33/548—Carbohydrates, e.g. dextran
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
  • G01N33/48—Biological material, e.g. blood, urine; Haemocytometers
  • G01N33/50—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing
  • G01N33/53—Immunoassay; Biospecific binding assay; Materials therefor
  • G01N33/558—Immunoassay; Biospecific binding assay; Materials therefor using diffusion or migration of antigen or antibody
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
  • G01N33/48—Biological material, e.g. blood, urine; Haemocytometers
  • G01N33/50—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing
  • G01N33/58—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing involving labelled substances
  • G01N33/585—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing involving labelled substances with a particulate label, e.g. coloured latex
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N2333/00—Assays involving biological materials from specific organisms or of a specific nature
  • G01N2333/435—Assays involving biological materials from specific organisms or of a specific nature from animals; from humans
  • G01N2333/575—Hormones
  • G01N2333/59—Follicle-stimulating hormone [FSH]; Chorionic gonadotropins, e.g. HCG; Luteinising hormone [LH]; Thyroid-stimulating hormone [TSH]
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N2458/00—Labels used in chemical analysis of biological material
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
  • Y10T428/2982—Particulate matter [e.g., sphere, flake, etc.]

Definitions

• the present invention relates to organic colored microparticles derived from an organic polymer, a reagent kit using the microparticles, and an in vitro diagnosis method.
• Microparticles composed of a polymer are used in various fields due to the ease of controlling their particle size, mechanical strength, particle size distribution, shape and degree of aggregation, examples of which include toner, anti-blocking materials of packing materials, insulating fillers, crystal nucleating agents, chromatographic fillers and abrasives. More recently, microparticles have also been applied to applications such as carriers for immunodiagnostic reagents, spacers of liquid crystal displays, standard particles for calibration of analytical equipment and standard particles for testing of porous films.
• the amount of microparticles composed of a polymer used in immunodiagnostic reagent carrier applications in particular is increasing, and the amount used is increasing especially in diagnosis methods using immunochromatographic methods (to be referred to as “immunochromatography”).
• immunochromatographic methods to be referred to as “immunochromatography”.
• POCT point-of-care testing
• viruses such as adenovirus, rotavirus or norovirus, hepatitis B, hepatitis C and other types of hepatitis testing, or pathogen testing for pathogens such as E.
• Immunochromatography is carried out by, for example, selectively reacting an antibody or antigen (ligand) labeled with chromogenic microparticles composed of a metal colloid or colored latex derived from polystyrene with a test substance on a chromatography substrate, and developing while forming a complex.
• an antigen or antibody that which specifically binds with the aforementioned ligand
• the color generated in immunochromatography is derived from the substance used for labeling.
• metal colloids since color is generated due to plasmon effects corresponding to the type of metal thereof, the resulting color is limited to a single color. For example, only red color is generated in the case of using gold colloid as described in Patent Document 1 indicated below.
• simultaneous testing of multiple parameters although effects can be expected to a certain degree by making contrivances to the detected location, this cannot be said to be preferable from the viewpoints of visibility and preventing erroneous diagnoses.
• a principle referred to as physical adsorption is typically used for the ligand binding method.
• Typical examples of ligand binding methods include physical adsorption, chemical bonding (covalent bonding), ionic bonding and inclusion.
• Physical adsorption refers to a binding method that utilizes hydrophobic interaction acting between a base material (such as chromogenic fine particles) and a material to be bound (such as a ligand).
• a base material such as chromogenic fine particles
• a material to be bound such as a ligand
• various mechanisms such as electrostatic action, intermolecular forces and other mechanisms are thought to be acting in addition to hydrophobic interaction.
• Physical adsorption is advantageous in terms of ease of the procedure and cost since the procedure can be carried out more easily than other binding methods.
• Patent Document 2 in the case of using polystyrene or other latex particles, multicoloration is possible by using a chromophore composed of a disperse dye, oil-soluble dye or pigment.
• an arbitrary method such as physical adsorption or chemical bonding can be typically selected for the method used to bind the ligand. Consequently, problems associated with the aforementioned physical adsorption and the like can also be avoided.
• the dyeing capacity of the particles is low at about 6% by weight, and the resulting color intensity is weak. Consequently, in the case of using for immunochromatography, it is not possible to obtain distinct coloring effects, thereby resulting in a lack of reliability.
• Patent Document 3 indicated below discloses microparticles obtained by staining cellulose, since the dyeing capacity relative to the amount of cellulose microparticles is low at about 20% by weight, the resulting stained microparticles are lightly colored. Although these microparticles are used in immunochromatography by imparting an antibody by physical adsorption or chemical bonding as described in Patent Document 4 indicated below, since the amount of antibody bound is insufficient and coloring of the microparticles per se is weak, distinct coloring results are unable to be obtained.
• Patent Document 1 Japanese Examined Patent Publication No. H7-60159
• Patent Document 2 Japanese Patent No. 2955405
• Patent Document 3 International Publication No. WO 2008/084854
• Patent Document 4 International Publication No. WO 2009/123148
• an object of the present invention is to provide organic colored microparticles that are highly chromogenic and enable multicoloration, and to achieve high sensitivity of an immunochromatography kit by binding a ligand thereto and applying to a diagnostic reagent, and particularly an immunochromatographic reagent.
• the inventors of the present invention succeeded in obtaining microparticles having a deep color by using cellulose as a starting material.
• the inventors of the present invention surprisingly found that, as a result of staining cellulose to a deep color, ligand binding becomes possible by physical adsorption, and ligands can also be bound by covalent bonding by introducing reactive groups as necessary. It was also found that, when this was applied to immunochromatography by using as a carrier for a diagnostic reagent, increased sensitivity of the immunochromatography kit was able to be realized, thereby leading to completion of the present invention.
• Organic colored microparticles having an average particle size of 10 nm to 1000 nm and a color intensity of 1.0 to 5.0.
• the diagnostic reagent kit according to claim [9] which is an immunochromatography kit.
• the organic colored microparticles according to the present invention have extraordinarily superior coloring properties in comparison with the coloring properties of latex particles of the prior art, and since they are able to adsorb antigen and other ligands, they can be applied to immunochromatography.
• the organic colored microparticles according to the present invention are able to provide a highly sensitive immunochromatography kit as a result of actualizing coloring in the case of being captured with a selective and specific reaction, and as a result of enabling multicoloration, are useful for simultaneous measurement of multiple test substances.
• the organic colored microparticles of the present invention enable the selection of an arbitrary method used to bind a ligand such as chemical bonding in addition to physical adsorption attributable to a dye, they can be applied to various test substances.
• the present invention enables rapid diagnoses with a low level of erroneous diagnosis, thereby greatly contributing to rapid diagnosis while also considerably expanding the application range of immunochromatography.
• the microparticles in the present invention refer to organic colored microparticles having an average particle size of 10 nm to 1000 nm and a color intensity of 1.0 to 5.0.
• the preferable range of average particle size is 100 nm to 900 nm, and more preferably 200 nm to 800 nm. If the average particle size exceeds 1000 nm, development becomes slow when using in an immunochromatography kit, rapid evaluation is prevented, the microparticles are easily captured on the developing film, and the background per se becomes colored, thereby resulting in a tendency for the expected coloring at the detected location to be ambiguous.
• the pore size of the developing film becomes smaller due to coating of the capture reagent. Consequently, the label tends to be captured easily, or in other words, the rate of false positives increases. As a result, the test kit cannot be considered to be reliable.
• Color intensity in the present invention is defined as the value obtained by measuring visual absorbance of a dispersion of the organic colored microparticles at an optical path length of 10 mm using an integrating sphere in the range of 400 nm to 800 nm, subtracting the background component of the dispersion medium, obtaining an absorbance curve of the dispersion matrix per se, dividing the maximum value (ABS) thereof by the weight percentage of the dispersion matrix, and calculating per 0.01% by weight. Since the use of an integrating sphere makes it possible to reduce the effects of diffuse light on the particles, the resulting value can serve as an indicator of the degree of coloring of the microparticles, and a larger value thereof can be judged to indicate more distinct coloring.
• color intensity of the microparticles of the present invention is 1.0 or more
• the color intensity is preferably as high as possible.
• Color intensity can be increased either by using a dispersed dye or pigment that demonstrates a high degree of coloring, or selecting means for increasing the number times staining is carried out.
• color intensity is preferably 1.0 to 5.0, more preferably 1.5 to 5.0 and even more preferably 2.0 to 5.0. In the case color intensity is lower than 1.0, visibility of a detected site becomes inferior when using in an immunochromatography kit due to weak coloring, thereby impairing reliability of test results.
• the material of the organic colored microparticles in the present invention has high color intensity and is stably dispersed.
• materials that can be deeply colored using dye or pigment can be applied, the realization of deep dyeing and strong dyeing is preferable when testing by immunochromatography and because this contributes to stabilization of kit quality during long-term storage.
• strong dyeing for example, a covalently bonding reactive dye can be used, and a material derived from cellulose can be used that can be dyed with a reactive dye.
• microparticles composed of a material derived from cellulose have a large number of hydroxyl groups, not only are they able to retain numerous reactive dyes by covalent bonding, but they also are able to maintain a stable dispersion in water and the like after being deep dyed.
• cellulose for the material of the organic colored microparticles is preferable, there are no particular limitations on the type thereof.
• recycled cellulose, purified cellulose or natural cellulose can be used.
• Partially derivatized cellulose may also be used.
• Preferably 20% by weight to 90% by weight of the organic colored microparticles is derived from cellulose. More preferably, 20% by weight to 80% by weight of the organic colored microparticles is derived from cellulose. Even more preferably, 20% by weight to 70% by weight is derived from cellulose.
• the fine particles of a desired average grain size may be obtained by sizing
• cellulose microparticles are prepared by using a congealing liquid obtained by dissolving cellulose in a good solvent thereof and mixing with water, organic solvent or ammonia and the like. The use of this method enables the grain size of the cellulose microparticles to be adjusted according to the composition of the congealing liquid.
• linter cellulose is dissolved in a good solvent of cellulose.
• a cuprammonium solution prepared using a known method is used for the good solvent.
• a mixed system of organic solvent, water and ammonia is mainly used for the congealing liquid.
• Congealing is carried out by adding the prepared cuprammonium solution while stirring this congealing liquid.
• a slurry can be obtained that contains the target cellulose microparticles.
• a cellulose microparticle dispersion or cellulose microparticles can be obtained by diluting, purifying and drying this slurry.
• a method that uses a dye is particularly preferable in terms of increasing color intensity, and various types of dyeing agents can be used, such as a direct dye, metal-containing dye, acidic dye, basic dye, disperse dye, sulfide dye, vegetable dye or naphthol dye.
• the coloring component preferably accounts for 10% by weight to 80% by weight, more preferably 20% by weight to 80% by weight, and even more preferably 30% by weight to 80% by weight of the organic colored microparticles.
• a reactive dye is preferably selected from the viewpoint of it being desirable to stain by covalent bonding.
• the proportion of the coloring component relative to the organic colored microparticles in the present invention can be calculated from change in weight.
• the proportion of the coloring component can be calculated from the weight of the particles able to be recovered and the weight of the particles before staining. For example, in the case of having stained 1.0 g of cellulose and 2.0 g of colored organic microparticles were obtained, the proportion of the coloring component is 50% by weight.
• the proportion of the coloring component can also be calculated by separating the organic microparticles and the coloring component by using a procedure for separating the organic colored microparticles and the coloring component as necessary, such as severing the covalent bonds by treating with acid or base, causing the microparticles to swell, or using another optimum cleaning procedure.
• the ligand in the present invention refers to a substance having the property of selectively and specifically binding to a specific test substance.
• examples of ligands include antibodies, antigens, enzymes, genes, hormones, cells, nucleic acids, peptides and proteins.
• a ligand can be physically adsorbed in the present invention simply by staining cellulose to a deep color using a dye.
• hydrophobic and hydrophilic balance may be adjusted by combining with derivatization of cellulose as necessary.
• Chemical bonding can be selected for the ligand bonding method in addition physical adsorption in the present invention.
• physical adsorption offers the advantages of a simpler procedure and lower costs, it has also been indicated as having problems like those indicated below. Examples of such problems include a loss of reaction selectivity due to the ligand binding site not being constant, and bound ligand being removed by the presence of surfactant. Therefore, in order to solve these problems, a chemical bonding method may be employed that forms a covalent bond with a ligand corresponding to the circumstances.
• a chemical bonding method may be able to further increase the number of ligands bound as compared with physical adsorption.
• Reactive groups in the present invention are used to covalently bond ligands.
• Typical examples of reactive groups include carboxyl group, amino groups, aldehyde groups, thiol groups, epoxy groups and hydroxyl groups. Although there are no particular limitations on the type thereof, carboxyl groups and amino groups are preferable.
• carboxyl groups a covalent bond is formed with an amino group of a ligand using a carbodiimide.
• the time at which the reactive group is introduced may be prior to staining or after staining.
• the site where the reactive group is introduced may be organic microparticles or a stained portion.
• a portion of the structure of the dye may be used as a reactive group.
• reactive groups in the present invention can be confirmed with an infrared spectral analyzer.
• an infrared spectral analyzer For example, in the case of a carboxyl group, absorption at about 1730 cm ⁇ 1 can be confirmed in the case of a free acid.
• absorption at about 1600 cm ⁇ 1 can be confirmed in the case of a primary amino group.
• an infrared spectral analyzer can only be used to determine whether or not a reactive group has been introduced.
• Reactive groups in the present invention preferably have a spacer structure of three atoms or more.
• the inventors of the present invention found that, when a reactive group is introduced into highly colored organic colored microparticles, a ligand is covalently bound and then used in immunochromatography, sensitivity is further improved if the reactive group has a spacer structure of three atoms or more. Although the reason for this is unclear, the possibility has been considered that a selective reaction between the ligand and test substance is impaired by the effects of steric hindrance and charge of the dye that is present in a large amount.
• a spacer structure refers to atoms present between the reactive groups and the organic colored microparticles.
• the spacer structure is branched, it refers to the number of atoms of the main chain.
• the reactive groups in this case are the carboxymethyl groups, and the spacer structure becomes —CH 2 —, namely a one atom spacer.
• reactive groups having a spacer structure are introduced using the following four types of methods.
• the structures of compounds 1 to 4 are respectively indicated with Chemical Formulas 1 to 4.
• dye is also inherently bound to a portion of the hydroxyl groups, the dye is omitted from the formulas.
• Stained cellulose microparticles and 5-hexenoic acid are allowed to react to introduce carboxyl groups.
• the number of atoms of the main chain, namely the number of atoms of the spacer structure, is 5.
• Stained cellulose microparticles and 16-heptadecenoic acid are allowed to react to introduce carboxyl groups.
• the number of atoms of the main chain, namely the number of atoms of the spacer structure, is 16.
• Stained cellulose microparticles and epichlorhydrin are allowed to react to introduce epoxy groups, and these are then further reacted with 6-aminohexanoic acid to introduce carboxyl groups.
• the number of atoms of the main chain, namely the number of atoms of the spacer structure, is 9.
• Stained cellulose microparticles and epichlorhydrin are allowed to react with introduced epoxy groups, and these are further reacted with ammonia to introduce primary amino groups.
• the number of atoms of the main chain, namely the number of atoms of the spacer structure, is 3.
• the spacer structure may be longer. Longer spacer structures can be achieved by changing the compound reacted with the stained cellulose microparticles, or the spacer structure can be additionally lengthened using an introduced reactive group. Although extremely long spacer structure can be introduced in theory, when considering from the viewpoints of ease of introduction and cost, the number of atoms is preferably 3 to 100, more preferably 3 to 50 and even more preferably 3 to 20.
• organic colored microparticles obtained using the aforementioned coloring method namely stained cellulose microparticles
• the dispersion may be stabilized by adding various types of reagents, surfactants and buffers.
• microparticles can be used alone or the dispersion can be adjusted to various concentrations by drying the dispersion as necessary.
• there are no particular limitations on the type of liquid in which the stained microparticles are dispersed provided it does not dissolve the microparticles or cause the microparticles to swell.
• Water, aqueous solutions of various inorganic compounds, alcohols, ethers, aldehydes, ketones, fatty acids, amines or other organic solvents can be used.
• a solvent may be used that is obtained by mixing various compounds at an arbitrary ratio, or these solvents can be used by mixing with a compatible hydrophobic solvent.
• the grain size distribution of the organic colored microparticles of the present invention is determined with the following formula (1):
• CV value (standard deviation in volume grain size distribution as determined with a particle size analyzer)/(volume average median diameter as determined with a particle size analyzer) ⁇ 100 (1)
• grain size distribution is preferably as small as possible, and is preferably 70% or less.
• the CV value can be adjusted according to the production conditions of the microparticles when desiring to make smaller, the particles may be sized by a procedure such as filtration or centrifugal separation at any stage before or after staining.
• the range of CV values is preferably 10% to 70%, more preferably 10% to 60% and even more preferably 10% to 50%.
• the organic colored microparticles of the present invention are preferably used in an immunoassay based on immunochromatography.
• immunochromatography involves preliminarily binding a label in the form of chromogenic microparticles composed of a metal colloid or colored latex derived from polystyrene to an antibody or antigen that specifically binds with an antigen or antibody serving as a test substance.
• an antibody or antigen that specifically reacts with an antigen or antibody is coated in lines at prescribed locations on a chromatography substrate.
• a complex is formed by contacting the labeled antibody or antigen with the antigen or antibody serving as the test substance, and although this complex is then developed on the chromatography substrate, this complex can be captured by primary antibody coated in the form of lines (sandwich assay). Since the label is also captured at this time, coloring occurs at the prescribed location. Since the presence of the test substance can be determined visually, this method has become widely popular in recent years as a simple test method.
• various types of testing can be performed by using not only an immune reaction using antigen or antibody, but also by using a ligand that specifically reacts with a test substance.
• immunochromatography is used in various other fields, such as biochemical analyses, genetic analyses and other arbitrary analytical reactions.
• a cellulose microparticle dispersion was measured using the UPA-EX150 Nanotrac Particle Size Analyzer manufactured by Nikkiso Co., Ltd. Unless specifically indicated otherwise, water was used for the liquid in which the cellulose microparticles were dispersed, the cellulose microparticles were measured at a concentration of about 0.1% by weight, and the cumulative number of measurements was 30. In addition, CV values were calculated by dividing the standard deviation in volume grain size distribution as obtained by 30 rounds of measurement by the volume average median diameter.
• the optical absorbance of cellulose microparticles as well as colored polystyrene latex and gold colloid serving as comparative examples was measured using a combination of the SV-722 Integrating Sphere and the JASCO ⁇ V-650 manufactured by Jasco Corp.
• the microparticles were measured at concentrations of 0.01% by weight to 0.1% by weight.
• values calculated by dividing the maximum value of the absorbance peak (ABS) over a visible light range of 400 nm to 800 nm by the weight percentage of the microparticles were determined in 0.01% by weight increments.
• a microparticle dispersion introduced with reactive groups was dried to obtain microparticles introduced with reactive groups.
• the infrared absorption spectrum was measured by the reflection method using the Spectrum 100 Infrared Spectral Analyzer manufactured by Perkin Elmer Co., Ltd., and a comparison was made of the spectra before and after introduction of reactive groups.
• carboxyl groups absorption of free acid of about 1730 cm ⁇ 1 was confirmed, while in the case of amino groups, absorption of primary amino groups of about 1600 cm ⁇ 1 was confirmed.
• the M-110-E/H Hydraulic Ultra-high-pressure Homogenizer manufactured by the Microfluidics Corp. was used to break up aggregations of microparticles in the cellulose microparticle dispersion and stained cellulose microparticle dispersion.
• the treatment pressure at that time was 50 MPa, and the microparticles were passed through the chamber serving as the high-pressure portion of the homogenizer 10 times.
• Linter cellulose was dissolved in a cuprammonium solution followed by diluting with water and ammonia to prepare a cuprammonium solution cellulose solution having a cellulose concentration of 0.37% by weight.
• the copper concentration of that solution was 0.13% by weight, and the ammonia concentration was 1.00% by weight.
• a congealing liquid was prepared having a tetrahydrofuran concentration of 90% by weight and water concentration of 10% by weight.
• 500 g of the preliminarily prepared cuprammonium cellulose solution having a cellulose concentration of 0.37% by weight were then added while slowly stirring 5000 g of the congealing liquid using a magnetic stirrer.
• the cellulose microparticles prepared in the manner described above were stained.
• 30 g of sodium sulfate and 1 g of Levafix Navy CA Gr. (Registered Trade Mark) manufactured by Dystar GmbH Corp. (to also be referred to as blue dye A) as reactive dye were added to 100 g of the cellulose microparticle dispersion adjusted to a microparticle concentration of 1.0% by weight, followed by heating to 60° C. using a constant temperature bath while stirring. After the temperature reached 60° C., 4 g of sodium carbonate were added followed by staining for 2 hours.
• the resulting crudely stained microparticles were washed with a 5% by weight aqueous solution of sodium hydroxide, recovered by centrifugal separation, washed with pure water and then recovered by centrifugal separation. This series of procedures was defined as one cycle. These procedures were carried out for up to 3 cycles to obtain stained microparticles. The proportion of the dye component was 49% of the weight of the organic colored microparticles.
• Example 1 Although the unstained cellulose microparticles obtained in Example 1 were stained using the same procedure, the procedure was carried out for a total of 10 cycles to obtain stained microparticles. The results of measuring average particle size and color intensity before and after staining are shown in the following Table 1.
• Cellulose microparticles and stained cellulose microparticles were obtained using the same method as Example 1 with the exception of using for congealing a congealing fluid having a tetrahydrofuran concentration of 95% by weight and a water concentration of 5% by weight.
• the results of measuring average particle size and color intensity before and after staining are shown in the following Table 1.
• Cellulose microparticles and stained cellulose microparticles were obtained using the same method as Example 1 with the exception of using for congealing a congealing fluid having an acetone concentration of 26.5% by weight, an ammonia concentration of 0.20% by weight and a water concentration of 73.3% by weight.
• the results of measuring average particle size and color intensity before and after staining are shown in the following Table 1.
• Cellulose microparticles and stained cellulose microparticles were obtained using the same method as Example 1 with the exception of using for congealing a congealing fluid having a tetrahydrofuran concentration of 97% by weight and a water concentration of 3% by weight.
• the results of measuring average particle size and color intensity before and after staining are shown in the following Table 1.
• the stained cellulose microparticles obtained in Comparative Example 1 were filtered using a filtration film derived from nitrocellulose having pore size of 0.8 ⁇ m manufactured by Nihon Millipore K. K. followed by sampling the filtrate.
• the results of measuring average particle size and color intensity are shown in the following Table 1.
• Example 1 Although stained microparticles were obtained by staining the unstained cellulose microparticles obtained in Example 1 using the same procedure as Example 1, only one cycle of the staining procedure was carried out. The results of measuring average particle size and color intensity before and after staining are shown in the following Table 1.
• Example 1 Although stained microparticles were obtained by staining the unstained cellulose microparticles obtained in Example 1 using the same procedure as Example 1 with the exception using 0.5 g of Levafix Rubine CA Gr. (Registered Trade Mark) manufactured by Dystar GmbH Corp. (red dye B) for the reactive dye, only one cycle of the staining procedure was carried out. The results of measuring average particle size and color intensity before and after staining are shown in the following Table 1.
• Stained microparticles were obtained using the unstained microparticles obtained in Example 1 by carrying out the same procedure as Example 8 with the exception of using 0.2 g of Levafix Navy CA Gr. (Registered Trade Mark) manufactured by Dystar GmbH Corp. (blue dye A) for the reactive dye.
• the results of measuring average particle size and color intensity before and after staining are shown in the following Table 1.
• Stained microparticles were obtained using the unstained microparticles obtained in Example 6 by carrying out the same procedure as Example 8 with the exception of using 0.2 g of Remazol Black B HI-GRAN 150 (Registered Trade Mark) manufactured by Dystar GmbH Corp. (blue dye C) for the reactive dye.
• Remazol Black B HI-GRAN 150 (Registered Trade Mark) manufactured by Dystar GmbH Corp. (blue dye C) for the reactive dye.
• the results of measuring average particle size and color intensity before and after staining are shown in the following Table 1.
• a performance evaluation was carried out by preparing immunochromatography kits using the stained, colored or chromogenic particles of Examples 1 to 9 and Comparative Examples 1 to 5.
• the stained or colored microparticles obtained in Examples 1 to 9 and Comparative Examples 1 to 4 were diluted with a phosphate buffer solution (to be referred to as “PBS”) to a solid concentration of 1% by weight, 1 ml of the resulting 1% by weight phosphate buffer suspension of stained microparticles and 1 ml of diluted antibody obtained by diluting mouse-derived antibody to human chorionic gonadotropin (to be referred to as “hCG”) (anti-hCG antibody #504 manufactured by Medix Biochemica Ab) with PBS to a concentration of 100 ⁇ g/ml were removed into an Eppendorf centrifuge tube and shaken for 2 hours at room temperature, and monoclonal antibody was bound to the stained microparticles, followed by centrifugally washing 3 times using PBS containing bovine serum albumin (BSA) at a concentration of 1% by weight and re-dispersing to a final volume of 2 ml to obtain an antibody-bound stained microparticle dispersion.
• PBS
• a test run antibody was sprayed and imprinted over a width of about 1 mm at a location 7 mm from one end (hereinafter indicating the lower end of a strip, with the other end indicating the upper end of the strip) of a commercially available membrane filter (HA120 manufactured by Nihon Millipore K. K., 25 mm ⁇ 300 mm) using a liquid spraying device perpendicular to the direction of development, or in other words, parallel to the long side of the membrane. More specifically, mouse-derived anti-h ⁇ subunit antibody (#6601 manufactured by Medix Biochemica Ab) was used for the test run antibody, and a liquid prepared to a concentration of 0.5 mg/ml with PBS was sprayed at 1.0 ⁇ L/cm.
• a control line antibody was sprayed and imprinted over a width of 1 mm at a location 12 mm from the lower end in the same manner. More specifically, rabbit-derived anti-mouse antibody (Z0259 manufactured by Dako Group, Inc.) was used for the control line antibody, and a liquid prepared to a concentration of 0.5 mg/ml with PBS was sprayed at 1.0 ⁇ L/cm. After spraying each antibody, the substrates were dried for 1 hour followed by blocking using borate buffer solution containing milk casein, washing using Tris-HCl buffer containing sucrose, and fixing overnight at room temperature to prepare a chromatography membrane.
• rabbit-derived anti-mouse antibody Z0259 manufactured by Dako Group, Inc.
• a filter paper absorption pad measuring 20 mm ⁇ 300 mm was contacted with the chromatography membranes using the resulting stained microparticles described in each of the examples and comparative examples at that their respective long sides so that they overlapped over a distance of 5 mm from the upper ends thereof, followed by cutting every 5 mm of width with a guillotine cutter to prepare samples. 60 samples can be obtained based on simple calculation.
• hCG was diluted with PBS containing BSA at a concentration of 1% by weight to contain hCG at concentrations of 100, 10 and 0 mIU/ml, respectively.
• a portion 2 mm from the lower end of the 5 mm wide kit samples obtained as described above was immersed in the sample solutions followed by development of the sample solutions. Ten minutes later, the coloring at the reaction site (label printed portion) on the membrane filter was observed visually. Evaluation criteria consisted of an evaluation of ( ⁇ ) in the case color was not observed at the test line, (+) in the case color was observed, (++) in the case coloring was clearly visible, and (+++) in the case of observing deep coloring. The evaluation results are shown in the following Table 2.
• Coloring of the control line was observed in all of the examples and comparative examples. At an hCG concentration of 100 mIU/ml, coloring of the test line was observed in Examples 1 to 9 and Comparative Examples 4 and 5. In addition, at an hCG concentration of 10 mIU/ml or less as well, coloring of the test line was observed in Examples 1 to 9 and Comparative Examples 4 and 5.
• Comparative Example 1 a phenomenon was observed in which apparent sensitivity decreased due to background coloring particularly at high antigen concentrations. In addition, a tendency was observed in which coloring occurred even in the absence of hCG in the samples, namely a tendency towards the occurrence of false positives.
• Example 7 when the particles of Comparative Example 1 were used after filtering, although background coloring remained, false positives were no longer observed, thereby indicating that excessively large particle size leads to the occurrence of false positives. An excessively large particle size is unsuitable for diagnostic reagent kits. Since false positives were not observed in Examples 1 to 9, Examples 1 to 9 can be said to have high sensitivity.
• reactive groups such as carboxyl groups or amino groups were introduced into the stained microparticles obtained in Example 1.
• a carboxylated stained microparticle dispersion was obtained using the same method as Example 11 with the exception of using 1654 g of 16-heptadecenoic acid (Wako Pure Chemical Industries, Ltd.) for the reaction agent added to carry out carboxylation.
• the results of measuring average particle size and color intensity for a portion of the resulting dispersion are shown in the following Table 3.
• the carboxylated and aminated stained microparticle dispersions obtained in Examples 10 to 14 were dried to prepare carboxylated and aminated stained microparticles, and the introduction of reactive groups was confirmed with an infrared spectral analyzer. Absorption increased at about 1730 cm ⁇ 1 for the carboxylated stained microparticles and at about 1600 cm ⁇ 1 for the aminated stained microparticles, thereby confirming successful introduction of reactive groups.
• a performance evaluation was carried out by preparing immunochromatography kits after chemically bonding antibody to the stained microparticles introduced with reactive groups of Examples 10 to 14.
• a 2-morpholinoethanesulfonate buffer (to be referred to as “MES”) having a pH of 5.2 and a concentration of 50 mM was prepared using 2-morpholinoethanesulfonic acid (Wako Pure Chemical Industries, Ltd.), sodium hydroxide and pure water, and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (Wako Pure Chemical Industries, Ltd., to be referred to as “carbodiimide”) was dissolved in MES buffer and adjusted to a carbodiimide concentration of 20% by weight.
• MES 2-morpholinoethanesulfonate buffer
• the microparticles were re-dispersed in the MES buffer, and the solid concentration was adjusted to a concentration of 1% by weight to obtain carboxylated stained microparticle MES buffer dispersions.
• 1 g of 20% by weight carbodiimide solution was added to 10 g of the carboxylated stained microparticle MES buffer dispersions and allowed to react for 1 hour in an environment at 25° C. using a constant-temperature shaking water bath, followed by centrifuging for 30 minutes at a speed of 10,000 rpm following completion of the reaction.
• the precipitate was removed by decantation followed by addition of phosphate buffer and stirring to obtain carbodiimide-activated stained microparticles dispersed in phosphate buffer. Dilution with decantation phosphate buffer solution was repeated three times using the same centrifuge as that used to wash the microparticles to remove unreacted carbodiimide. The resulting carbodiimide-activated stained microparticles were then used to prepare antibody-bound stained microparticles by chemical bonding using the same procedure as that used to prepare antibody-bound stained microparticles by physical absorption.
• the microparticles were re-dispersed in the aforementioned phosphate buffer and the solid concentration was adjusted to a concentration of 1% by weight to obtain an aminated stained microparticle PBS buffer dispersion.
• 1 g of 25% by weight glutaraldehyde solution (Wako Pure Chemical Industries, Ltd.) was added to 10 g of the aminated stained microparticle PBS buffer dispersion and allowed to react for 2 hours in an environment at 37° C. using a constant-temperature shaking water bath, followed by centrifuging for 30 minutes at a speed of 10,000 rpm following completion of the reaction.
• the precipitate was removed by decantation followed by addition of phosphate buffer and stirring to disperse glutaraldehyde-activated stained microparticles in phosphate buffer. Dilution with decantation phosphate buffer solution was repeated three times using the same centrifuge as that used to wash the microparticles to remove unreacted glutaraldehyde. The resulting glutaraldehyde-activated stained microparticles were then used to prepare antibody-bound stained microparticles by chemical bonding using the same procedure as that used to prepare antibody-bound stained microparticles by physical absorption. Unreacted aldehydes were removed by adding 1 g of glycine prior to adding bovine serum albumin at a concentration of 0.1% by weight.
• the antibody-bound stained microparticles by chemical bonding obtained in Examples 10 to 14 and the antibody-bound stained microparticles by physical absorption obtained in Example 1 were evaluated for use as immunochromatography microparticles.
• the organic colored microparticles of the present invention are useful for use as a label for immunodiagnosis and immunochromatography, and can be preferably used in a highly sensitive immunochromatography kit that allows rapid evaluation.

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