JP2000088853A - Diagnostic particles - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a particle for a diagnostic agent which has a low absorbance in an unaggregated state, does not exceed the measurement limit of an inspection instrument in a wide concentration range, and does not cause a prozone phenomenon even in a high concentration range. To provide. SOLUTION: (A) Structural unit 2 derived from (meth) acrylate having an aliphatic hydrocarbon group having 4 to 20 carbon atoms.
0 to 100% by weight, (B) 0 to 10% by weight of a structural unit derived from an unsaturated carboxylic acid, and (C) a structural unit derived from a vinyl monomer copolymerizable with the (meth) acrylate and the unsaturated carboxylic acid. A polymer composed of 0 to 80% by weight is a constituent component.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to particles for diagnostic agents, and more particularly to particles for diagnostic agents used for measurement of biochemical substances, particularly for medical tests.

[0002]

2. Description of the Related Art A method for carrying an immunoreactive substance or nucleic acid such as an antibody or an antigen on a carrier particle and detecting a test substance such as a corresponding antigen, antibody, enzyme or nucleic acid by a specific reaction is a method used in clinical tests. It is used as an important tool. For example, a dispersion of polymer particles having an antibody supported on the surface thereof by physical adsorption or chemical bonding is prepared, and a test solution containing an antigen for the antibody is added. A change in the surface state of the polymer particles or crosslinking between the particles occurs, and the polymer particles aggregate. The aggregation of the polymer particles can be visually observed on a suitable plate, but usually, the change in the turbidity of the test solution caused by the aggregation is measured.
The test substance (antigen) in the test solution can be quantified.

As such a measurement system (quantitative method), a method of measuring the rate of change in turbidity after the addition of a test solution (rate assay method), a quasi-equilibrium turbidity after a certain period of time after the addition of the test solution, There is a method of measuring degrees (endpoint method). In any method, the amount (concentration) of the test substance and the turbidity (change rate or quasi-equilibrium turbidity)
And a calibration curve obtained by measuring the relationship in advance.

In these calibration curves, however, the absorbance monotonically increases from low to high concentrations of the analyte, regardless of whether the gradient is constant or not, and the prozone region does not exist. Is required.

Conventionally, polystyrene particles or carboxylic acid-modified styrene-based particles have been known as polymer particles constituting particles for diagnostic agents. Here, examples of the carboxylic acid used in a small amount to obtain the carboxylic acid-modified styrene-based particles include methacrylic acid, acrylic acid, itaconic acid, and fumaric acid. The above-mentioned polystyrene-based particles (polystyrene particles or carboxylic acid-modified styrene-based particles) become constituent particles of a diagnostic agent when sensitized with an antibody or the like. As a medium of the diagnostic agent, a physiological saline solution to which a substance for adjusting the performance of the diagnostic agent is added is used.

However, in the case where the turbidity due to aggregation of polymer particles is measured by measuring the absorbance, the absorbance of a conventionally known polystyrene-based latex is large even in an unaggregated state (concentration of the test substance = 0). ,
Even in a region where the concentration of the test substance is low, there is a problem that the measurement limit of the test device is exceeded. In addition, if the concentration of polymer particles (latex concentration) is lowered to reduce the absorbance in the non-aggregated state, a prozone phenomenon occurs in the region where the concentration of the test substance is high, and the test solution needs to be diluted. A great deal of time and effort is required on site. In order to solve such a problem and prevent the occurrence of the prozone phenomenon in the calibration curve, selection of the antibody to be used, sensitization method, sensitization conditions, optimization of the composition of the dispersion liquid, and the like are performed. However, no satisfactory solution has been found.

Further, as an approach from the material side to prevent the occurrence of the prozone phenomenon in the calibration curve without causing the absorbance after aggregation to exceed the measurement limit of the inspection instrument, fluorine having a lower refractive index than polystyrene-based latex is used. Techniques for applying the contained latex material are introduced (for example, JP-A-61-247966, JP-A-63-200655, and JP-A-63-27891.
No. 3, JP-A-1-266111).

However, the fluorine-containing latex material has a problem in terms of production cost, such as the necessity of a pressure vessel for producing the latex material. Further, the specific gravity of the latex particles is as large as 1.5 or more, and the dispersion stability is poor, and there is a problem from the viewpoint of storage stability. Further, the glass transition temperature (Tg) is so low that redispersion after centrifugation is difficult,
Another problem is that it is difficult to perform an immobilization operation by physical adsorption of an antigen or an antibody.

On the other hand, in order to improve the visibility and detection sensitivity of test results, and to measure and test biochemical substances using the color or fluorescence derived from polymer particles as a label, dyes and Polymer particles dyed and dyed with a fluorescent substance are desired. However, there is no known polymer particle constituting the diagnostic agent particle having good dyeing and dyeing properties.

[0010]

SUMMARY OF THE INVENTION The present invention has been made based on the above circumstances. A first object of the present invention is to provide a novel diagnostic agent particle containing a specific polymer as a component. A second object of the present invention is to measure the turbidity due to the aggregation of particles by measuring the absorbance, the absorbance in an unaggregated state (test substance concentration = 0) is low, and the calibration between the test substance concentration and the absorbance is performed. It is an object of the present invention to provide diagnostic agent particles that do not cause the absorbance in a wide concentration range to exceed the measurement limit of a test instrument and do not cause a prozone phenomenon even in a high concentration range when measuring a line. A third object of the present invention is to provide diagnostic agent particles capable of measuring a calibration curve having a wide concentration range of a test substance in which a prozone phenomenon does not occur even when sensitization treatment is performed under standard conditions. It is in. A fourth object of the present invention is to provide diagnostic agent particles having good staining and staining properties with a dye or a fluorescent substance. A fifth object of the present invention is to provide an aqueous dispersion of particles whose surface has been sensitized with an antigen, antibody or nucleic acid, by adding a test substance which specifically binds to the antigen, antibody or nucleic acid to the particle, It is an object of the present invention to provide diagnostic agent particles which can be suitably used for a test for quantifying the test substance by aggregating and measuring a change in turbidity due to the aggregation of the particles.

[0011]

Means for Solving the Problems The particles for diagnostic agents of the present invention comprise (A) a structural unit derived from a (meth) acrylate having an aliphatic hydrocarbon group having 4 to 20 carbon atoms (hereinafter referred to as "structural unit A"). 20 to 100% by weight, (B) 0 to 10% by weight of a structural unit derived from an unsaturated carboxylic acid (hereinafter, referred to as “structural unit B”), and (C) the (meth) acrylate and unsaturated A polymer (hereinafter, referred to as a “specific (co) polymer”) composed of 0 to 80% by weight of a structural unit derived from a vinyl monomer copolymerizable with a carboxylic acid (hereinafter, referred to as a “structural unit C”) is a constituent component. It is characterized by the following.

The following forms are preferable for the particles for a diagnostic agent of the present invention. [1] The ratio of the structural unit A is 65 to 100% by weight, the ratio of the structural unit B is 0 to 5% by weight, and the ratio of the structural unit C is 0 to 35% by weight. [2] The aliphatic hydrocarbon group constituting the (meth) acrylate has a cyclic structure. [3] When the average particle diameter of the diagnostic agent particles is d (nm), and the absorbance at a wavelength of 600 nm measured with respect to an aqueous dispersion having a solid concentration of 0.05 w / v% of the diagnostic agent particles is A, The condition shown in Expression 1 must be satisfied. [4] At least a part of the surface is dyed or colored. [5] Carrying biochemical substances.

[0013]

Equation 1: A <f (d) = (M ₀ −M ₁ d + M ₂₎
d ² −M ₃ d ³ + M ₄ d ⁴ ) (where M ₀ = 0.012573, M ₁ = 0.0020732, M ₂ = 6.333 × e ⁻⁵ , M ₃ = 8.7935 × e ^{−) 8} , M ₄ = 3.529 × e ⁻¹¹ )

In the present invention, the average particle diameter d (n
"m)" means a number average particle diameter obtained by taking an electron micrograph of particles with a transmission electron microscope and measuring the particle diameter of 200 or more randomly selected particles.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The diagnostic agent particles of the present invention have a specific (co) polymer (specific copolymer or specific polymer) as a constituent component. Specific examples of the (meth) acrylate (hereinafter, referred to as “monomer (A)”) used to obtain the structural unit (A) constituting the specific (co) polymer include 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, n-butyl acrylate, n-butyl methacrylate, t-butyl acrylate, t-butyl methacrylate, isobutyl acrylate, isobutyl methacrylate, pentyl acrylate, pentyl methacrylate,
Stearyl acrylate, stearyl methacrylate,
Alkyl (meth) acrylates having a chain alkyl group such as lauryl acrylate and lauryl methacrylate; (meth) acrylates having a cyclic aliphatic group such as cyclohexyl acrylate, cyclohexyl methacrylate, cyclohexylethylene glycol methacrylate, cyclohexyl dipropylene glycol methacrylate; methyl substitution Substituted cyclohexyl (meth) acrylates and cyclohexenedi (meth) acrylates in which a part of hydrogen atoms of a cyclohexyl group such as cyclohexyl acrylate is substituted by an alkyl group having 1 to 4 carbon atoms, and the like, and these can be used alone or Two or more can be used in combination.

Of these, preferred are 2-ethylhexyl acrylate, t-butyl methacrylate, cyclohexyl methacrylate, cyclohexyl acrylate, substituted cyclohexyl acrylate and substituted cyclohexyl methacrylate, and particularly, aliphatic hydrocarbons having a cyclic structure such as cyclohexyl methacrylate and cyclohexyl acrylate. A (meth) acrylate containing a hydrogen group is preferable because it has little nonspecific adsorption and is excellent in storage stability.

The content of the structural unit (A) in the specific (co) polymer is usually 20 to 100% by weight,
Preferably, it is 65 to 100% by weight. When the content ratio of the structural unit (A) is 20% by weight or more,
The particles for a diagnostic agent can have excellent adsorptivity and binding reactivity with an immunoreactive substance (for example, an antibody).

The unsaturated carboxylic acid (hereinafter, referred to as "monomer (B)") used to obtain the structural unit (B) constituting the specific copolymer contains a radical polymerizable unsaturated bond and It is a polymerizable monomer having a carboxyl group in the molecule. Specific examples of the monomer (B) include acrylic acid, methacrylic acid, crotonic acid, itaconic acid, fumaric acid, and maleic acid. These may be used alone or in combination of two or more. be able to. The content ratio of the structural unit (B) in the specific copolymer is usually 0 to 10% by weight, preferably 0 to 5% by weight. Diagnostic agent particles comprising the specific copolymer into which the structural unit (B) is introduced are mainly subjected to sensitization treatment by chemical bonding, and diagnostic agent particles into which the structural unit (B) is not introduced are mainly used. Used for sensitization treatment by physical adsorption.

Specific examples of the vinyl monomer (hereinafter referred to as "monomer (C)") used to obtain the structural unit (C) constituting the specific copolymer include styrene and α-.
Methyl styrene, vinyl toluene, divinyl benzene,
Aromatic vinyl compounds such as styrene sulfonic acid; (meth) acrylates having an alkyl group having 1 to 3 carbon atoms such as methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, isopropyl acrylate, and isopropyl methacrylate; vinyl esters such as vinyl acetate Compounds and the like,
These can be used alone or in combination of two or more. Structural unit (C) in specific copolymer
Is usually 0 to 80% by weight, preferably 0 to 35% by weight.

The particles for a diagnostic agent of the present invention, even if they are polymer particles composed of only a specific (co) polymer, are coated on the surface of core particles made of a material other than the specific (co) polymer. A composite particle in which a polymer layer is formed continuously or intermittently may be used, but it is preferably a polymer particle composed only of a specific (co) polymer because of easy production. . In addition, examples of the constituent material of the core particles include polystyrene, carboxyl group-modified polystyrene, and silica. The diagnostic agent particles of the present invention are non-magnetic particles that do not contain a superparamagnetic substance or the like.

The particle size of the particles for a diagnostic agent of the present invention is not particularly limited, but the average particle size d (number average particle size) is 0.03 to 0.03.
It is preferably in the range of 10 μm, more preferably 0.05 to 1 μm. If the average particle diameter d is too small, the measurement sensitivity in the low concentration range of the test substance tends to be insufficient. On the other hand, when the average particle diameter d is excessively large, the measurement sensitivity in a high concentration range of the test substance tends to be insufficient.

The average particle diameter of the particles for diagnostic use of the present invention is d (nm), and the solid concentration of the particles for diagnostic use is 0.05.
Wavelength 600 nm measured for w / v% aqueous dispersion
When the absorbance at is represented by A, it is preferable to satisfy the condition represented by the above formula 1, more preferably the condition represented by the following formula 2. According to the particles for a diagnostic agent satisfying the condition of the above formula 1, the absorbance in the unaggregated state is lower than that of the polystyrene-based latex, and when measuring the calibration curve between the concentration of the test substance and the absorbance, the absorbance in a wide concentration range Can be measured by an inspection instrument. In addition, according to the conventionally known polystyrene-based latex, the absorbance measured under the same conditions is always equal to or more than f (d).

[0023]

Formula 2: A <k · f (d) (where k is less than 1, preferably 0.95 or less,
More preferably, it is 0.90 or less.)

The diagnostic agent particles of the present invention preferably carry a biochemical substance. Examples of such biochemicals include antigens, antibodies, enzymes, nucleic acids, and the like.
The method of sensitizing the particles for a diagnostic agent with a biochemical substance is not particularly limited. For particles for a diagnostic agent composed of a specific copolymer having a structural unit (B), the chemical bonding method is mainly used. In the case of the particles for a diagnostic agent which are employed and are composed of a specific copolymer having no structural unit (B), the physical adsorption method is mainly employed.

The antigen or antibody carried by the diagnostic agent particles of the present invention is not particularly limited as long as it reacts with a component generally contained in a specimen (a substance to be tested in a test solution). For example, anti-plasmin antibody for antiplasmin test, anti-D-dimer antibody for D-dimer test, anti-FDP antibody for FDP test, anti-tPA antibody for tPA test, antithrombin-antithrombin complex antibody for TAT test, FPA test Antigen or antibody for coagulation / fibrinolysis related test such as anti-FPA antibody; anti-B for BFP test
FP antibody, anti-CEA antibody for CEA test, anti-AFP antibody for AFP test, anti-ferritin antibody for ferritin test, CA
Antigens or antibodies for tumor-related tests such as anti-CA19-9 antibodies for 19-9 tests; anti-apolipoprotein antibodies for apolipoprotein tests, anti-β2-microblobrin antibodies for β2-microblobrin tests, α1-microglobulin tests Antigen or antibody for serum protein-related tests such as anti-α1-microglobulin antibody, anti-immunoglobulin antibody for immunoglobulin test, anti-CRP antibody for CRP test; anti-HC for HCG test
An antigen or an antibody for testing endocrine function such as G antibody; an anti-HBs antibody for testing HBs antigen; an HBs antigen for testing HBs antibody;
HCV Antigen for HCV Antibody Test, HIV for HIV-1 Antibody
-1 antigen, HIV-2 antibody test HIV-2 antigen, HT
HTLV-1 antigen for LV-1 test, mycoplasma antigen for mycoplasmosis test, toxoplasma antigen for toxoplasma test, streptolysin O antigen for ASO test, etc .; antigen or antibody for infectious disease-related tests; DNA antigen for anti-DNA antibody test, RF Antigens or antibodies for autoimmunity-related tests such as heat-denatured human IgG for tests; antigens or antibodies for drug analysis such as anti-digoxin antibodies for digoxin tests and anti-lidocaine antibodies for lidocaine tests, but are not limited thereto. Not something. As the antibody, either a polyclonal antibody or a monoclonal antibody may be used.

The particles for a diagnostic agent of the present invention may be at least partially dyed or colored with a dye, a pigment or the like. According to such particles for a diagnostic agent, the visibility of aggregation in an inspection is improved. I do. Examples of the dyes that can be preferably used include oil-based dyes such as Sudan Orange R and Sudan Blue; and water-soluble or alcohol-soluble dyes such as Orange II, Congo Red, Anthazole O, Alizarin Red S, and Spirit Blue. Can be mentioned. Of these, oil-soluble dyes are particularly preferred in terms of dyeing properties.

The diagnostic agent particles of the present invention may have at least a portion of the surface dyed with a fluorescent substance to impart fluorescence. According to such diagnostic agent particles, fluorescence measurement can be performed. By doing so, the quantitative sensitivity can be significantly improved. Here, examples of the fluorescent substance that can be preferably used include organic fluorescent dyes or pigments such as fluorescein, eosin, and luminogen yellow; and inorganic fluorescent dyes or pigments such as zinc sulfide, cadmium sulfide, and europium compounds. . Of these, oil-soluble fluorescent dyes are particularly preferred in terms of dyeing properties. The diagnostic drug particles of the present invention, which are colored or stained as described above, can be used with or without carrying biochemicals such as antigens, antibodies, enzymes, and nucleic acids.

In the test using the diagnostic agent particles of the present invention, a conventionally known tester for measuring turbidity can be used. The method for measuring turbidity by such an inspection machine includes a rate assay method for measuring the rate of change in turbidity after the addition of a test liquid (substance to be inspected), and a fixed time after the addition of the test liquid (substance to be inspected). There are end point methods for measuring the quasi-equilibrium turbidity after the lapse of time, and among these, measurement by a rate assay method is preferable.

[0029]

EXAMPLES Examples of the present invention will be described below, but the present invention is not limited to these examples. In the following, “parts” means “parts by weight”. <Examples 1 to 7 and Comparative Example 1> 100 parts of the monomers shown in Table 1 below, 500 parts of water, 1 part of potassium persulfate,
0.2 parts of sodium dodecylbenzenesulfonate was charged into a 5 liter glass flask equipped with a stirrer and polymerized under a nitrogen atmosphere at a temperature of 80 ° C. for 6 hours to give polymer particles (diagnostic agent particles of the present invention and A dispersion of particles for a diagnostic agent for comparison) was prepared. In all the polymerization reaction systems, the polymerization conversion was 98% or more. Table 1 shows the average particle diameter d of the obtained polymer particles.
Are shown together.

[Conditions of Formula 1] Polymer particles (diagnostic drug particles) obtained in Examples 1 to 7 and Comparative Example 1 described above.
For each of the conditions [A <f
In order to confirm whether (d)] was satisfied, the absorbance A at a wavelength of 600 nm was measured for an aqueous dispersion of the diagnostic agent particles having a solid content concentration of 0.05 w / v%. The results are shown in Table 1.

[Evaluation of Staining Property] In 100 ml of an aqueous dispersion of 1% by weight of each of the polymer particles (diagnostic agent particles) obtained in Examples 1 to 7 and Comparative Example 1, 2% by weight of Congo Red was added. 10 ml of a toluene solution and 1 g of sodium dodecylbenzenesulfonate as an emulsifier were added and dispersed well by ultrasonic dispersion, followed by stirring at 80 ° C. for 3 hours to dye polymer particles. After cooling, remove the toluene with a steam strip and then
The polymer particles were separated by filtration, and centrifugal sedimentation / redispersion treatment was repeated four times to remove unadsorbed dye, thereby purifying the polymer particles. The dyeability of the purified polymer particles was determined by the following five-step evaluation.
The results are shown in Table 1.

(Evaluation) 1: Stained slightly. 2: Slightly stained. 3: Stained at medium density. 4: Dyes well. 5: Dye very well.

[Range of Calibration Curve] Each of the polymer particles (diagnostic agent particles) obtained in Examples 1 to 7 and Comparative Example 1 was used in a 1/15 M phosphate buffer (pH 7.
2) A mixture of 1 part by volume and 3 parts by volume of physiological saline (hereinafter P
BS), the polymer particles are dispersed so as to have a concentration of 1% by weight, an equal amount of a 1 mg / ml solution of anti-CRP antibody (rabbit) is added thereto, and the mixture is kept at 56 ° C. for 30 minutes. Processing was performed. After the sensitization treatment, unsensitized antibodies are removed by dialysis and gel filtration, and a diluent (PBS containing 0.1% bovine serum albumin) is added so that the particle concentration becomes 0.13% by weight. An anti-CRP antibody sensitized latex diagnostic was obtained. For each of the anti-CRP antibody-sensitized latex diagnostic agents thus obtained, a calibration curve was measured using a CRP antigen standard solution as described below to evaluate the performance of the latex reagent. As a result, in the calibration curves according to Examples 1 to 7, the prozone phenomenon did not occur in a wide range of the concentration of the test substance from 0 to 100 mg / dl.

• Apparatus: Hitachi 7020 automatic analyzer • Wavelength used: 570 nm, measurement temperature: 37 ° C. Test substance (0-100 mg / dl CRP standard solution): 3 μl • First reagent (bovine serum albumin 0. 1% PBS): 200 μl • Second reagent (latex diagnostic agent): 200 μl

After mixing and stirring the test substance, the first reagent, and the second reagent, a rate assay method is used to measure the difference (change amount) between the turbidity after 50 seconds and the turbidity after 200 seconds. And the calibration curve was measured.

[0036]

[Table 1]

In Table 1, abbreviations in the types of monomers indicate the following monomers, respectively. • CHMA: cyclohexyl methacrylate • TBMA: t-butyl methacrylate • 2EHA: 2-ethylhexyl acrylate • AA: acrylic acid • MAA: methacrylic acid • TA: itaconic acid • ST: styrene

[Application Example of Diagnostic Agent] Each of the polymer particles (diagnostic agent particles) obtained in Example 1, Example 2, Example 4, and Comparative Example 1 was sensitized with an anti-CRP antibody. An anti-CRP sensitized latex diagnostic was obtained. For each of the anti-CRP antibody-sensitized latex diagnostic agents thus obtained, a calibration curve was measured using a CRP antigen standard solution as described below to evaluate the performance of the latex reagent.

• Apparatus: Hitachi 7020 automatic analyzer • Working wavelength: 600 nm, measurement temperature: 37 ° C. • Test substance (CRP standard solution of 0 to 100 mg / dl): 3 μl • First reagent (bovine serum albumin 0. 1% PBS): 200 μl • Second reagent (latex diagnostic agent): 200 μl

[Measurement Example 1 (Endpoint Method)]
Using the particles for a diagnostic agent of Example 1, Example 2, Example 4 and Comparative Example 1 sensitized with the P antibody (0.1 w / v%), the above-mentioned test substance, the first reagent, and the second reagent After mixing and stirring 21
The calibration curve was measured by measuring the absorbance after 1 second. The results are shown in FIG. As shown in FIG. 1, when the particles for a diagnostic drug of Comparative Example 1 were used, the initial turbidity was high, and even at a low CRP concentration, it exceeded the measurement limit (absorbance = 3) of the test instrument, and further measurement was impossible. there were. When the particles for diagnostic agents of Examples 1, 2, and 4 were used, the initial turbidity was low, and the measurement could be performed without exceeding the measurement limit of the test equipment even at a high CRP concentration.

[Measurement Example 2 (Late Assay)] Anti-CR
Using the particles for diagnostic agent (0.15 w / v%) of Example 1, Example 2, Example 4 and Comparative Example 1 sensitized with P antibody,
After mixing and stirring the test substance, the first reagent, and the second reagent,
A calibration curve was measured by a rate assay method that measures the difference (change amount) between the turbidity after 36 seconds and the turbidity after 126 seconds. The results are shown in FIG. As shown in FIG. 2, the prozone phenomenon was observed when the particles for a diagnostic agent of Comparative Example 1 were used, but the prozone phenomenon was observed when the particles for a diagnostic agent of Examples 1, 2, and 4 were used. No zone phenomenon was observed.

[Detection of AFP antibody by sensitizing fluorescent particles]
The polymer particles obtained in Example 4 were dyed with eosin, which is a fluorescent dye, to obtain fluorescent particles. The fluorescent particles were dispersed in PBS to a concentration of 1% by weight, and an equal amount of a 1 mg / ml solution of an anti-AFP antibody (mouse) was added thereto.
A sensitization treatment was performed at 56 ° C. for 30 minutes. After sensitization, unsensitized antibodies are removed by dialysis and gel filtration.
A diluent (PBS containing 0.1% bovine serum albumin) was added so that the particle concentration became 0.1% by weight, and anti-AFP was added.
Antibody-sensitized fluorescent particles were obtained. On the other hand, 0.1 mg of non-fluorescent magnetic particles immobilized with an anti-AFP antibody (mouse) recognizing another epitope and 500 ng / ml of AFP are mixed in advance to bind AFP to the non-fluorescent magnetic particles,
The anti-AFP antibody-sensitized fluorescent particles (1 mg) were added, and the mixture was heated at 37 ° C. for 10 minutes. As a result, the fluorescent particles were further bound to the magnetic particles to which the AFP antibody had been bound via AFP.
Next, the magnetic particles were separated by magnetic separation, washed three times with a diluent, and then the fluorescence intensity of the magnetic particle dispersion was measured with a fluorescence spectrophotometer. As a result, the fluorescence intensity when 500 ng / ml of AFP was used was 120 times that when no AFP was used. Thus, it was possible to detect the AFP antibody bound to the magnetic particles using the fluorescent particles of the present invention as an index.

[0043]

(1) According to the present invention, it is possible to provide a novel diagnostic particle containing a specific polymer as a component. (2) According to the particles for a diagnostic drug of the present invention, the absorbance in an unaggregated state is low. Therefore, when measuring the calibration curve between the concentration of the test substance and the absorbance, the absorbance in a wide concentration range is less than the measurement limit of the test instrument. The prozone phenomenon does not occur even in a high concentration region. (3) According to the particles for a diagnostic agent of the present invention, even when sensitization treatment is performed under standard conditions, it is possible to measure a calibration curve in which the concentration range of the test substance in which the prozone phenomenon does not occur is wide. (4) The particles for a diagnostic agent of the present invention have excellent dyeing and dyeing properties with a dye or a fluorescent substance.
In the inspection, the visibility of aggregation is good, and when a fluorescent dye is used, quantitative measurement sensitivity can be greatly improved by performing fluorescence measurement. (5) The diagnostic agent particles of the present invention are prepared by adding a test substance that specifically binds to the antigen, antibody or nucleic acid to an aqueous dispersion of particles whose surface has been sensitized with an antigen, antibody or nucleic acid. By aggregating the particles and measuring the change in turbidity due to the aggregation of the particles, it can be suitably used for the test for quantifying the test substance. (6) The diagnostic agent particles of the present invention do not require a special device (for example, a pressure vessel) for producing the particles, and are advantageous in terms of a production device and a production cost. (7) The diagnostic agent using the diagnostic agent particles of the present invention has good storage stability of particles constituting the particles (particles after sensitization treatment),
Less aggregation when stored for a long time compared to particles obtained by sensitizing a conventionally known polystyrene latex or the like. This is an important feature in maintaining the quality of diagnostics,
This is a great advantage from the viewpoint of maintaining the quality of the diagnostic product. (8) The diagnostic drug particles of the present invention have less so-called non-specific adsorption of a physiologically active substance other than the antibody / antigen corresponding to the sensitized antigen / antibody.

[Brief description of the drawings]

FIG. 1 is a calibration curve obtained by measuring a CRP antigen by an endpoint method using particles for a diagnostic drug sensitized with an anti-CRP antibody.

FIG. 2 is a calibration curve obtained by measuring a CRP antigen by a late assay method using particles for a diagnostic drug sensitized with an anti-CRP antibody.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Satoshi Katayose 2-11-24 Tsukiji, Chuo-ku, Tokyo Inside JSR Corporation (72) Inventor Mitsuhiro Murata 2-11-24 Tsukiji, Chuo-ku, Tokyo JSR Inside (72) Inventor Toru Masukawa 2-11-24 Tsukiji, Chuo-ku, Tokyo Inside JSR Co., Ltd. (72) Inventor Masaaki Kitashima 2-11-24 Tsukiji, Chuo-ku, Tokyo Inside JSR Co., Ltd.

Claims (5)

[Claims] 1. A structural unit 2 derived from (A) a (meth) acrylate having an aliphatic hydrocarbon group having 4 to 20 carbon atoms.
0 to 100% by weight, (B) 0 to 10% by weight of a structural unit derived from an unsaturated carboxylic acid, and (C) a structural unit derived from a vinyl monomer copolymerizable with the (meth) acrylate and the unsaturated carboxylic acid. Diagnostic agent particles comprising a polymer consisting of 0 to 80% by weight as a component. 2. The diagnostic agent particle according to claim 1, wherein the aliphatic hydrocarbon group constituting the (meth) acrylate has a cyclic structure. 3. The diagnostic agent particles according to claim 1, wherein the average particle size of the diagnostic agent particles is d (nm), and the solid concentration of the diagnostic agent particles is 0.05 w / v%. Wherein the absorbance at a wavelength of 600 nm measured with respect to the aqueous dispersion of the formula (A) is A, the particles satisfying the following formula (1): Equation 1: A <f (d) = (M ₀ −M ₁ d + M ₂₎
d ² −M ₃ d ³ + M ₄ d ⁴ ) (where M ₀ = 0.012573, M ₁ = 0.0020732, M ₂ = 6.333 × e ⁻⁵ , M ₃ = 8.7935 × e ^{−) 8} , M ₄ = 3.529 × e ⁻¹¹ ) 4. The diagnostic agent particle according to claim 1, wherein at least a part of the surface is stained or colored. 5. The diagnostic agent particle according to claim 1, which carries a biochemical substance.