WO1999021012A1

WO1999021012A1 - Colored latex

Info

Publication number: WO1999021012A1
Application number: PCT/JP1998/003429
Authority: WO
Inventors: Takuya Wada; Satoshi Obana; Yuji Kaneko; Shinichi Egi
Original assignee: Sekisui Chemical Co., Ltd.
Priority date: 1997-10-21
Filing date: 1998-07-31
Publication date: 1999-04-29
Also published as: AU8461998A

Abstract

A colored latex having a sufficiently deep color and being excellent in visual judgement easiness and detection sensitivity when used in immunoassay. This latex comprises colored latex particles having a degree of dispersion of 10 % or below, an average particle diameter of 0.05 to 3.0 νm, an average specific gravity of 1.02 to 3.0, and a colorant content of 10 % by weight or higher.

Description

Description Colored latex Technical field

The present invention relates to a colored latex (hereinafter, referred to as a colored latex), and particularly to a colored latex that can be used in an immunoassay for measuring an antigen or an antibody. Background art

Conventionally, as one of the immunoassays for detecting a target substance consisting of a specific antigen or antibody by utilizing a specific reaction by an antigen-antibody, an antibody or a method of sensitizing a target substance in a sample to fine particles An agglutination method in which an antigen is bound by an immune reaction and the aggregation state of fine particles generated by the binding is measured is a simple measurement method, and is generally used because it can be visually determined. As other immunoassays, a radioimmunoassay, an enzyme immunoassay, an immunofluorescence assay and the like are also widely used.

Furthermore, a method of detecting a substance to be detected by visual judgment using a substance that immunologically binds to the substance to be detected and combining an immunological reaction with the principle of chromatography is known as an immunochromatography method or an immunochromatography method. The law has been widely used in recent years.

The immunochromatography method involves immobilizing an antibody (or antigen) against an antigen (or an antibody) to be detected on a chromatographic medium and forming a reaction site on the chromatographic medium as a stationary phase. While contacting the detection particles sensitized with an antibody (or antigen) capable of binding to the detection substance with the sample, the antibody (or antigen sensitization by this contact) Or the antigen (or antibody) in the sample reacts with the antigen (or antibody) in the sample, and the detection particles-the antibody used in the sensitization (or the antigen used in the sensitization) A complex consisting of the following is generated): a method in which the sample is brought into contact with the reaction site by moving the sample on the chromatographic medium. Thereby, at the reaction site, The complex is bound to the immobilized antibody (or the immobilized antigen), and the detection particles are captured. The presence or absence of the detection particles is visually determined to determine the presence of the analyte in the sample. The presence can be determined.

In the above-described immunochromatography method and the agglutination method, colored fine particles are often used as detection particles in order to facilitate visual judgment. Examples of such detection particles include colloidal particles such as colloidal metal particles or colloidal metal oxide particles that naturally exhibit a color depending on the particle size and preparation conditions; and latex particles composed of synthetic molecules are colored. Latex particles obtained by performing

Colored latex particles obtained by polymerizing a monomer together with a colorant are used. However, the color tone of the above-mentioned colloidal particles is determined by the particle size and the preparation conditions, so that it is difficult to obtain a desired clear dark color tone, and the colored latex particles are prepared with a darker color tone. It is more preferable in terms of visual sensation and good sensitivity (Japanese Patent Application Laid-Open No. 5-109950).

However, although the color tone of the colored latex particles can be selected, for example, as described in JP-A-5-1950, the amount of the dye added to 0.6 g of the latex particle group is 0.62. 2 g or less, and even if all of the added dyes are contained, the degree of dye in the colored latex particles is 5.

It was 86% by weight or less, and the content of the dye was small. As a result, a sufficiently dark color was not obtained. Therefore, when used for immunoassay, there was a problem that visual judgment was poor.

Also, as the colored latex particles become darker, the colorant used adheres to the surface of the latex particles, and the original surface state of the latex particles is impaired.In the immunochromatographic method, for example, a membrane filter such as a membrane filter is used. or clogged in the pores of the chromatogram rough medium, with or cause nonspecific aggregation by aggregation method, be colored darker, not necessarily lead to improved performance, a summary of _t invention there is a problem that

A first object of the present invention is to provide a colored latex which is colored sufficiently dark and has excellent visual judgment and detection sensitivity when used for immunoassay. The colored latex of the first aspect of the present invention is a colored latex particle group having a particle dispersity of 10% or less, an average particle diameter of 0.05 to 3.0 m, and an average specific gravity of 1.02 to 3.0. That is, the content of the coloring agent in the colored latex particles is 10% by weight or more.

A second object of the present invention is to reduce the possibility of clogging in pores of a chromatographic medium such as a membrane filter used in an immunochromatography method, and to use a non-specific agglutination method even when used in a latex agglutination method. It is an object of the present invention to provide a colored latetus that is less likely to cause odor.

The colored latex of the second invention is a colored latex particle group having a particle dispersion degree of 10% or less, an average particle diameter of 0.05 to 3.0 im, and an average specific gravity of 1.02 to 3.0. That is, the content of the colorant on the particle surface of the colored latex particle group is within 12% by volume. BRIEF DESCRIPTION OF THE FIGURES

Figure 1 shows the standard spectrum of Solvent Blue.

FIG. 2 shows the + ion spectrum of the latex used in Example 3 before coloring. FIG. 3 is a ten ion spectrum of the colored latex obtained in Example 3. FIG. 4 is a + ion spectrum of the colored latex obtained in Comparative Example 3. Detailed Disclosure of the Invention

Hereinafter, the first present invention will be described.

The colored latex particles used in the first aspect of the present invention are composed of latex particles and a coloring agent contained therein. The latex particle is not particularly limited as long as it is a latex particle conventionally used in the field of immunoassay, and can be obtained by polymerizing or copolymerizing various monomers. Here, monomers include, for example, polymerizable unsaturated aromatics such as styrene, chlorostyrene, α-methylstyrene, divinylbenzene and vinyltoluene: for example, (meth) acrylic acid, itaconic acid, maleic acid, fumaric acid Polymerizable unsaturated carboxylic acids such as acid; polymerizable unsaturated sulfonic acid such as sodium styrene sulfonate or a salt thereof; , (Meth) methyl acrylate, (meth) ethyl acrylate, (meth) acrylic acid

— Polymerizable carboxylic acids such as n-butyl, mono (2-) hydroxyl-methacrylate, glycidyl (meth) acrylate, ethylene glycol-di (meth) acrylate, and tribromophenyl (meth) acrylate Esters; (meth) acrylonitrile, (meta) acrolein, (meta) acrylamide, N-methylol (meta) acrylamide, methylenebis (meth) acrylamide, butadiene, Unsaturated carboxylic acid amides such as isoprene, vinyl acetate, vinylpyridine, N-vinylpyrrolidone, vinyl chloride, vinylidene chloride, vinyl bromide, polymerizable unsaturated nitriles, vinyl halides, conjugated gens, etc. Can be mentioned. These monomers can be used alone or in combination of two or more. Among these, a copolymer of styrene and at least one selected from polymerizable unsaturated carboxylic acids and polymerizable unsaturated sulfonic acids or salts thereof is particularly preferable. The polymerizable unsaturated carboxylic acid is not particularly limited as long as it is a polymerizable carboxylic acid having a double bond, and examples thereof include methacrylic acid, acrylic acid, itaconic acid, and maleic acid. The polymerizable unsaturated sulfonic acid or salt thereof is not particularly limited as long as it is a polymerizable sulfonic acid having a double bond, and includes, for example, sodium styrenesulfonate.

Examples of the polymerization method include a dispersion polymerization method, a suspension polymerization method, and an emulsion polymerization method, and the emulsion polymerization method is preferable.b

The colorant is not particularly limited as long as it can color latex particles, and examples thereof include a dye and a pigment. The dye is appropriately selected according to the color tone, the type of solvent that dissolves the dye, the type of latex, and the like. Oil-soluble dyes, direct dyes, acid dyes, basic dyes, azo dyes, aqueous dyes, Examples thereof include reactive dyes, and oil-soluble dyes are particularly preferable. Specific examples of the oil-soluble dye include Solvent Blue, Solvent Red, Solvent Orange, Solvent Green, and the like. Examples of the dye include a food dye, a vital dye, a cosmetic dye, and a pharmaceutical dye.

Since the colored latex particles used in the first aspect of the present invention are used as a carrier for immunoassay, the particles have a degree of dispersion of 10% or less and an average particle diameter of 0.05 to 3.0 nm. The average specific gravity is limited to 102 to 3.0. The dispersion degree and average particle diameter of the particles according to the first aspect of the present invention mean those measured as follows. The colored latex particles were photographed with a transmission electron microscope, and the particle size of each of the 500 particles was measured by image processing of the obtained electron micrograph, and the average value, standard deviation, and fluctuation were measured. Find the coefficient [(standard deviation / mean value) X 100 numerical value]. This average value is the average particle size referred to in the first invention, and the coefficient of variation is the degree of dispersion of the particles referred to in the first invention. In addition, the average specific gravity means a value measured as follows. Prepare solutions of various specific gravities measured using a specific gravity meter, float the powder of the dried colored latex particles on the solution, observe the sedimentation state of the powder, and completely settle the powder. First, the specific gravity of the solution floating in the solution is defined as the average specific gravity in the first present invention.

The colored latex of the first invention comprises the above colored latex particles, and the content of the coloring agent in the colored latex particles is limited to 10% by weight or more. When the content is less than 10% by weight, the coloring is not sufficiently dark, and when used for immunoassay, the effect of improving visual judgment and detection sensitivity cannot be expected.

The content of the colorant in the colored latex particles as referred to in the first aspect of the present invention can be calculated from the latex peak area Α and the colorant peak area の of the chromatogram obtained by subjecting the colored latex particles to gas chromatography. Β Ζ (A + B) 1 XI 00 This is a value obtained from the equation.

Hereinafter, an example of the method for producing the colored latex of the first invention will be described. First, a dye that is soluble in a solvent in which latex particles are insoluble is selected, and the dye is dissolved in the solvent to near saturation solubility. Examples of such a solvent include ethers such as ethyl ether and isopropyl ether; alcohols such as methanol and ethanol: methylene chloride; ethylene dichloride; chloroform; carbon tetrachloride; Methyl acetate; methyl ethyl ketone; cyclohexane; cyclopentane; tetrahydrofuran; toluene; hexane; heptane; water and the like; one or more types depending on the type of dye. Used as a mixed solution.

Next, latex particles are added to the dye solution and dispersed. Next, the dye solution containing the latex particles is heated or heated with stirring. Then As the dye is gradually contained in the latex particles, the degree of dye in the solution gradually decreases. When the concentration of the dye in the solution decreases, the dye tends to equilibrate in the latex particles and in the solution.Therefore, the concentration of the dye in the solution is reduced by evaporating the solvent or gradually adding new dye. Do not fall. Such a method promotes the transfer of the dye from the solution to the latex particles.

Methods for vaporizing the solvent include a method of evaporating by heating and a method of lowering the pressure of the reaction system to lower the boiling point of the solvent. It is preferable because it can be shared with. However, in this case, the boiling point of the solvent is preferably lower than the reaction temperature at the time of polymerization of the latex particles, and when the treatment temperature in the coloring treatment step is 35 to 50 ° C, the boiling point is less than 80 ° C. It is preferred to select a solvent. In order to keep the dye concentration constant, or to prevent the dye from precipitating due to the dye concentration exceeding the saturation solubility, a solvent reflux mechanism for adjusting the evaporation rate of the solvent should be provided. preferable.

If the heating or heating temperature in the above coloring treatment step is lower than 30 ° C, the speed at which the dye is incorporated into the latex particles becomes slow and impractical. However, when the colored latex obtained is converted into a reagent, the performance tends to be unsatisfactory. C is preferred. Further, the coloring treatment time varies depending on the particle size of the latex particles and the heating / heating temperature, but is usually preferably 2 hours to 10 days.

In the above-mentioned coloring treatment step, the ratio of the latex particle group to the colorant is preferably maintained such that the colorant exceeds 2 g per 10 g of the latex particle group. By performing the coloring treatment as described above, a colored latex containing much more coloring agent than before can be obtained.

As a more preferred form of the colored latex of the first invention, a latex particle group is added to an organic solvent solution of an oil-soluble dye, and the oil-soluble dye is contained in the latex particle group by heating or stirring under heating. Can be mentioned. The above-mentioned production method is the same as that described in the first method for producing a colored latex of the present invention except that an oil-soluble dye is used as a dye and an organic solvent is used as a solvent. Same as the law. Hereinafter, the second present invention will be described.

The present inventors have found that if a colorant is excessively present on the surface of latex particles in order to increase the color tone of the colored latex, the obtained colored latex particles can be used in an immunochromatographic method to obtain a chromatographic filter such as a membrane filter. It was found that it is necessary to limit the content of the coloring agent on the surface of the colored latex particles, since the pores of the graphing medium are easily clogged, and when used in the latex agglomeration method, non-specific agglomeration is likely to occur. The present invention has been completed.

The second group of colored latex particles used in the present invention comprises latex particles and a colorant contained therein. The latex particles are the same as those used in the first present invention. Further, the coloring agent is the same as that used in the first invention.

The colored latex particles used in the second invention are used as a carrier for immunoassay, so that the degree of dispersion of the particles is 10% or less, the average particle diameter is 0.05 to 3.0 urn, It is limited to those having an average specific gravity of 1.02 to 3.0. The definition of the degree of dispersion, average particle diameter and average specific gravity of the particles according to the second invention is the same as that of the first invention.

The colored latex of the present invention is composed of the above colored latex particles, and the content of the coloring agent on the particle surface of the colored latex particles is limited to 12% by volume or less, preferably 10% by volume. Within. In addition, the above-mentioned particle surface means a surface layer portion within a range of 10 A from the particle surface. When the content of the colorant on the particle surface exceeds 12% by volume, the risk of clogging in the pores of a chromatographic medium such as a membrane filter when used in an immunochromatographic method increases, and the latex agglutination method Even if used for non-specific aggregation, non-specific aggregation is likely to occur.

The content of the colorant on the surface of the particles of the colored latex particles according to the second aspect of the present invention is a value determined as follows. That is, using a time-of-flight secondary ion mass spectrometer (hereinafter referred to as TOF-SIMS), the colorant, latex particles before coloring, and latex particles after coloring are measured under the same conditions. Then, the mass count A of the peak specific to the obtained colorant, the latex before coloring at the same peak From the mass count B of the particle group and the mass count of the latex particle group after coloring at the same peak,

The content (volume%) of the colorant on the surface of the particles is determined by the following formula: C (C-B) / (A-B)] 100.

Hereinafter, an example of the method for producing the second colored latex of the present invention will be described. First, latex particles made of, for example, a styrene-methacrylic acid copolymer are produced by emulsion polymerization or the like. The obtained latex particles are added to a solution in which the dye is dissolved in a solvent, and heated or heated with stirring. The heating or heating temperature is set to a temperature not lower than the reaction temperature during latex particle polymerization at 30 ° C or higher, but the higher the temperature, the faster the coloring reaction proceeds. The coloring reaction time is determined by the type of the dye, the particle size of the latex particles, the composition, and the like, and is usually preferably 2 hours to 10 days. After reacting for a predetermined time, the dye solution and the colored latetus are separated by centrifugation or the like, and then the colored latex particles are dispersed in a solvent such as water to obtain a colored latex.

Examples of the solvent for the dye during the coloring reaction include ethers such as ethyl ether and isopropyl ether; alcohols such as methanol and ethanol; methylene chloride; ethylene dichloride; chloroform: nitrogen tetrachloride; and acetic acid. Ethyl: methyl acetate; methyl ethyl ketone; cyclohexane; cyclopentane; tetrahydrofuran; toluene; hexane; heptane; water, etc., depending on the type of dye, one or more types are mixed. Used as a solution.

As described above, in the colored latex of the second aspect of the present invention, the content of the coloring agent on the particle surface of the colored latex particles is limited to 12% by volume or less. If the colorant content is too low, the color tone of the colored latex itself will become lighter.To prevent this, for example, mix a blue or red colorant with a black colorant to maintain the color tone while maintaining the color tone. A method of reducing the amount of colorant present on the surface, or as a post-treatment, using colored latex as seed particles and seed polymerization to form a layer of 0.01 / m or less on the surface, resulting in colored latex particles A method of reducing the amount of the colorant present on the surface may be employed.

Further, as the colored latex of the second invention, the particles obtained by the first invention Of latex particles having an average particle size of 0.05 to 3.0 m and an average specific gravity of 1.02 to 3.0 having a particle dispersity of 10% or less. Particularly preferred is a colored latex having a content of the agent of at least 10% by weight, wherein the content of the coloring agent on the surface of the particles of the colored latex particles is within 12% by volume. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, examples of the present invention will be described, but the present invention is not limited to these examples. Example 1

In 200 ml of a dye solution prepared by dissolving 2.4 g of an oil-soluble dye, Solventable, in methanol, the particle size is 0.32 m, the degree of dispersion of the particle size is 3.9%, and the specific gravity is 1.0. 6 g of latex particles (polystyrene-based latex, manufactured by Sekisui Chemical Co., Ltd.) was added thereto in a quantity of 6 g, and heated and stirred at 45 ° C for 3 days. In order to prevent the dye concentration in the solution from decreasing during the three days, methanol was gradually evaporated so that the dye concentration at the time of preparation was not lowered. Subsequently, the colored latex was removed by centrifugation, and redispersed in water to obtain a colored latex suspension. The content of the dye in the colored latex particles was measured by gas chromatography, and was found to be 12.0% by weight. 36 g). The dispersion of the obtained colored latex particles was 4.2%, the average particle size was 0.32 / m, and the average specific gravity was 18. Comparative Example 1

The dye solution in which 1.2 g of Solvent Blue was dissolved in methanol instead of the dye solution 2.0 M in which Solvent Blue was dissolved in 2.4 g of methanol in Example 1 was used. The same procedure as in Example 1 was carried out except using ml, to obtain a suspension of colored latex. The content of the coloring agent in the colored latex particles was measured by gas chromatography to be 5.6% by weight. This means that about 0.59 g of the dye was contained in 10 g of the raw material latex particle group). Further, the degree of dispersion of the obtained colored latex particles was 4.1%, the average particle size was 0.32, and the average specific gravity was 1.10. Comparative Example 2

As in Example 1, 2.4 g of a dye solution in which 2.4 g of an oil-soluble dye, Solvent Blue, was dissolved in methanol, had a particle diameter of 0.32 m and a degree of dispersion of the particle diameter of 3.9%. A latex particle group having a specific gravity of 1.04 (polystyrene-based latex, manufactured by Sekisui Chemical Co., Ltd.) was added to 6 g, and the mixture was heated and stirred at 45 ° C. for 3 days. However, the method of this heating and stirring treatment was different from that of Example 1 and was as follows. In other words, a cooling tube was attached to the reactor so that methanol did not decrease, and all evaporated methanol was refluxed into the dye solution.

After the above-mentioned heating and stirring treatment for 3 days, the colored latex was taken out in the same manner as in Example 1, and the colored latex was taken out and redispersed in water to obtain a colored latex suspension. The dye content of the colored latex was measured by gas chromatography to be 6.6% by weight. (This is because about 0.71 g of the dye was contained in 10 g of the raw latex particle group.) That would be). The dispersion of the obtained colored latex particles was 4.2%, the average particle size was 0.32 μιη, and the average specific gravity was 1.11. Example 2

In 200 ml of a dye solution obtained by dissolving 2.4 g of an oil-soluble dye, solvent blue, in methanol, the particle size is 0.10 m, the degree of dispersion of the particle size is 2.1%, and the specific gravity is 1.04. 6 g of latex particles (polystyrene latex, manufactured by Sekisui Chemical Co., Ltd.) was added thereto, and the mixture was heated and stirred at 45 ° C. for 3 days. In order to prevent the dye concentration in the solution from decreasing during the three days, methanol was gradually evaporated so that the dye concentration at the time of preparation was not lowered. Subsequently, the colored latex was removed by centrifugation, and redispersed in water to obtain a colored latex suspension. The dye content of this colored latex was determined by gas chromatography to be 15.6% by weight. (This means that the dye contained about 1.85 g per 10 g of the raw latex particles). Further, the degree of dispersion of the obtained colored latex particle group was 2.3%, the average particle size was 0.10 m, and the average specific gravity was 1.22. Performance evaluation

Using the colored latexes of Examples 1 and 2 and Comparative Examples 1 and 2, kits for immunochromatography were produced as described below, and the performance of the colored latetus was evaluated.

(1) Preparation of sensitized colored latex

The obtained colored latex suspension was diluted with a phosphate buffer (hereinafter, referred to as PBS) so that the solid content concentration was 1% by weight. 100 ml of a monoclonal antibody (manufactured by DAKO) against human chorionic gonadotropin (hereinafter referred to as hCG) was added to 1 ml of the obtained 1% by weight colored latex phosphate buffer suspension in PBS, and the resulting suspension was added to the suspension. // Transfer 1 ml of the diluted antibody obtained to 1 g / m 1 to an Eppendorf centrifuge tube and shake at room temperature for 2 hours to sensitize the colored latex particles with the monoclonal antibody. , Centrifugally washed three times using PBS containing bovine serum albumin (hereinafter referred to as BSA) at a concentration of 0.1% by weight, and resuspended to a final volume of 2 ml. A sensitized colored latex suspension was obtained.

(2) Preparation of chromatographic medium

A polystyrene latex (manufactured by Sekisui Chemical Co., Ltd., average particle size 0.45 ^ m) was diluted with PBS so that the solid content concentration was 0.6% by weight, and 1 ml of the resulting solution was diluted with a rabbit antibody to hCG (concentration of 1%). (0.0 g / ml PBS solution) 1 ml was placed in an Ebbendolf centrifuge tube and shaken at room temperature for 2 hours to sensitize the latex particle group with the egret antibody. Then, it was centrifugally washed three times using PBS containing BSA at a concentration of 0.1% by weight, and resuspended to a final volume of 2 ml to prepare solid phase latex particles A.

In addition, solid-state latex particles B were prepared in the same manner except that hCG was used instead of the egret antibody to hCG in the preparation of solid-state latex particles A. Next, a membrane strip of 12 × 60 ram was cut from a commercially available membrane filter (Millipore, S RHF), and one end of the strip (hereinafter, this one end was referred to as the strip). (The other end is called the upper end of the strip.) 3 Omm from the other end and is perpendicular to the developing direction using a liquid ejector, that is, parallel to the shorter side of the strip. Then, solid latex particles A were jet-printed with a width of 2 mm, and similarly, solid latex particles B were jet-printed at a position of 45 mm from the lower end of the strip, followed by drying and fixing. In addition, a 12 x 15 mm paper-absorbent pad was contacted so that the short side of 12 mm was aligned with the short side of the strip so that the distance between the top and bottom was 5 mm.

(3) Preparation of Conduit Gate Pad and Preparation of Kit

The sensitized colored latex で Ο 1 Ι obtained in the above (1) was applied to a 12 x 15 mm glass wool filter, and dried well to obtain a condensate pad. Place the short side of 12 mm on the short side of the strip so that the gap from the lower end of the strip of the chromatographic medium obtained in (2) above overlaps 5 mm from the strip. By aligning and contacting, an immunochromatographic kit was manufactured. (Not used in this performance evaluation, but the obtained immunochromatographic kit was placed in a housing made of plastic or the like. The housing may be used in various forms, but the printed part of solid latex A and solid latex B must be visible from the outside).

(4) Chromatographic processing

As a sample, a hCG-containing sample was prepared as follows. hCG was diluted with PBS containing BSA at a concentration of 0.1% by weight to give hCG concentrations of 100, 50, 25, 12.5, 6.3 and 0 mIU / m, respectively. One hCG-containing sample was prepared. 5 mm was immersed in the sample liquid from the lower end of the conjugate pad, which was the lower end of the whole kit obtained in (3) above, to spread the sample liquid. After a lapse of 5 minutes, a blue signal from the sensitized colored latex particles was visually observed at the reaction site on the membrane filter (the printed portion of the solid phase latex A). When the blue color is not recognized (1), when blue color is recognized (+), when blue color is clearly recognized (+ +), when blue color is strongly recognized is (+ + +), the observation result is 7 o as shown in Table 1 table 1

Example 3

In 200 ml of a dye solution obtained by dissolving 2.4 g of solvent-soluble dye, methanol, in methanol, the particle size is 0.32, the degree of dispersion of the particle size is 3.9%, and the specific gravity is 1.04. 6 g of latex particles (polystyrene-based latex, manufactured by Sekisui Chemical Co., Ltd.) was added thereto and heated and stirred at 45 ° C for 1 day. Then, the colored latex was removed by eccentric separation treatment, and redispersed in water to obtain a suspension of the colored latex. The content of the dye on the particle surface in the colored latex particle group was determined by measuring the mass count corresponding to the peak intensity of m350 of Solvent Blue obtained using TOF-SIMS, and the latex before coloring in the same beak. The mass count of the particle group and the mass count of the latex particle group after coloring at the same peak were found to be 9.1 volume （(Details of this measurement are described below. This is explained in the section on measuring the content). Further, the degree of dispersion of the obtained colored latex particle group was 4.0%, the average particle size was 0.32 / zm, and the average specific gravity was 1.16. Comparative Example 3

In place of the dye solution (200 ml) obtained by dissolving 2.4 g of solvent in methanol in Example 3, 3.6 g of solvent was dissolved in methanol. The same procedure as in Example 3 was carried out except that 2000 mU of the dye solution was used, to obtain a suspension of a coloring latex. The content of the dye on the particle surface in the colored latex particles was determined to be 12.6% by volume in the same manner as in Example 3. (Details of this measurement were described in the following section. This is explained in the section on measuring the content of dye on the surface). The degree of dispersion of the obtained colored latex particle group was 4.2%, the average particle size was 0.32 m, and the average specific gravity was 1.19. Measurement of the content of dye on the surface of particles in colored latex particles

[Analysis and observation method]

The sample solution was dropped on a silicon wafer, dried at room temperature, and then subjected to spectrum measurement. Solvent blue standard dye was dissolved in black-mouthed form and dropped on a silicon wafer to form a thin film, and the surface was measured. The analysis conditions were as follows. TO F-S IMS: Made by Chinas Evans, TFS Surface Analyzer. Primary ion: 69 G a +. Ion voltage: 15 kV. Ion current: 2 / A. Analysis time: 5-10 minutes. Mass range: 1-1000 m s s. Analysis area: 177 mX 177 im. Prevention of charge: Mesh loading on sample surface, neutralization with electron irradiation, random raster scan.

(Quantitative determination of surface dye)

Figure 1 shows the standard spectrum of Solvent Blue, Figure 2 shows the + ion spectrum of the latex used in Example 3 before coloring, and Figure 3 shows the + ion spectrum of the colored latex obtained in Example 3. FIG. 4 shows the + ion vector of the colored latex obtained in Comparative Example 3. Based on the peak intensity of m350, which is a characteristic fragment of Solvent Blue, in each of the obtained spectra, the content of the dye on the particle surface of the colored latex particle group based on the above equation was determined. Was calculated. As a result, the content of the dye on the particle surface in the colored latex particles obtained in Example 3 was 9.1% by volume, and the content of the dye on the particle surface in the colored latex particles obtained in Comparative Example 3 was 9.1% by volume. Was 12.6% by volume.

Performance evaluation

The performance evaluation of the colored latex obtained in Example 3 and Comparative Example 3 was performed as follows. I got it.

Example 1 was repeated except that the colored latex obtained in Example 3 and Comparative Example 3 was used instead of the colored latex obtained in Example 1 in the section of performance evaluation in Example 1. In the section on performance evaluation, (1) Preparation of sensitized colored latex, (2) Preparation of chromatographic medium, (3) Preparation of conjugate pad and preparation of kit Was prepared.

The hCG-containing sample solution prepared in the same manner as (4) chromatographic treatment in the performance evaluation section of Example 1 was added to the hCG-containing sample solution as the lower end of the entire kit obtained as described above. The sample solution was developed by immersing 5 mm from the lower end of the pad. After a lapse of 5 minutes, a blue signal from the sensitized colored latex particles at a reaction site (printed portion of solid phase latex A) on the membrane filter was visually observed. The case where blue is not recognized is (1), the case where blue is recognized (+), the case where blue is clearly visible is (+ +), and the case where blue is strongly recognized is (+ + +). The results are shown in Table 2. In order to check the clogging of the colored latex particles in the membrane filter, the sensitized colored latex particles between the upper end of the conduit pad and the reaction site (the printing section of solid phase latex A) were observed. The blue signal from was also visually observed, and determined based on the same criteria as the above visual determination criteria. The results are shown in Table 2.

A and B in the observation site column in Table 2 are as follows.

A: Reaction site

B: Between the conduit pad and the reaction site

Table 2

Industrial applicability

The configuration of the colored latex of the first invention is as described above, and provides a colored latex that is colored sufficiently dark and has excellent visual judgment and detection sensitivity when used for immunoassay. . Therefore, the colored latex of the first aspect of the present invention is suitably used as a particle for detection by an immunochromatography method or the like. In addition, if the measurement sensitivity is suppressed to the conventional level, the amount of the antibody used can be reduced, so that the use of the colored latex of the first aspect of the present invention makes it possible to reduce the cost of the product.

The configuration of the colored latex of the second invention is as described above.When this colored latex is used in the immunochromatography method, the colored latex is clogged when the colored latex is transferred from the conduit pad to the membrane filter. Since there is no, The amount of colored latex flowing to the reaction site is stabilized, the measurement error is reduced, and the visibility at the time of judgment is improved. In addition, since the flowability of the colored latex particles flowing on the membrane filter is good, the reaction time can be reduced. As a result, a large amount of the colored latex particles flow into the reaction site, and the measurement sensitivity increases.

Further, the colored latex of the second aspect of the present invention hardly causes non-specific aggregation even when used in the latex aggregation method.

Claims

The scope of the claims

(1) A colored latex comprising a group of colored latex particles having an average particle diameter of 0.05 to 3.0 / m and an average specific gravity of 1.02 to 3.0 having a particle dispersity of 10% or less. A colored latex, wherein the content of the colorant in the particle group is 10% by weight or more.

(2) The first claim obtained by adding latex particles to an organic solvent solution of an oil-soluble dye as a coloring agent, and heating or stirring the mixture to contain the oil-soluble dye in the latex particles. The colored latex according to the above item.

(3) The claim 1 or 2, wherein the latex particles are a copolymer of styrene and at least one selected from a polymerizable unsaturated carboxylic acid and a polymerizable unsaturated sulfonic acid or a salt thereof. Colored latex.

(4) A colored latex particle having a degree of particle dispersion of 10% or less, a colored latex particle group having an average particle diameter of 0.05 to 3.0 / im and an average specific gravity of 1.02 to 3.0. A coloring latex, wherein the content of the coloring agent on the particle surface of the particle group is within 12% by volume.

(5) The colored latex according to claim 4, wherein the latex particles are a copolymer of styrene and at least one selected from a polymerizable unsaturated carboxylic acid and a polymerizable unsaturated sulfonic acid or a salt thereof. .