阅读说明：本技术 一种基质金属蛋白酶-3测定试剂盒及其制备方法 (Matrix metalloproteinase-3 determination kit and preparation method thereof ) 是由 伍卫姣 郑慧铃 黄爱 刘道锦 陈婷 张雪娇 舒芹 于 2020-07-29 设计创作，主要内容包括：本发明公开了一种基质金属蛋白酶-3测定试剂盒及其制备方法,所述试剂盒包括试剂R1,所述试剂R1以质量分数计包括如下组分：缓冲液100mmol/L～200mmol/L,防腐剂0.1％～0.2％,无机盐1％～10％,络合剂0.2g/L～0.8g/L,硫脲0.1％～1％,表面活性剂0.2％～1.5％,pH 6.5～7.5；其中,所述表面活性剂为胆酸钠、脱氧胆酸钠、牛黄脱氧胆酸钠、鹅脱氧胆酸钠中的至少一种。该试剂盒准确度高,偏差在10％以内；灵敏度可以达到5ng/mL；精密度高,试剂盒精密度CV值为1.688％～2.257％。(The invention discloses a matrix metalloproteinase-3 determination kit and a preparation method thereof, wherein the kit comprises a reagent R1, and the reagent R1 comprises the following components in parts by mass: 100 mmol/L-200 mmol/L of buffer solution, 0.1-0.2% of preservative, 1-10% of inorganic salt, 0.2-0.8 g/L of complexing agent, 0.1-1% of thiourea, 0.2-1.5% of surfactant and 6.5-7.5 of pH; wherein the surfactant is at least one of sodium cholate, sodium deoxycholate, sodium taurodeoxycholate and sodium chenodeoxycholate. The kit has high accuracy, and the deviation is within 10%; the sensitivity can reach 5 ng/mL; the precision is high, and the precision CV value of the kit is 1.688-2.257%.)

1. A matrix metalloproteinase-3 assay kit, which comprises a reagent R1, wherein the reagent R1 comprises the following components in parts by mass:

100 mmol/L-200 mmol/L of buffer solution, 0.1-0.2% of preservative, 1-10% of inorganic salt, 0.2-0.8 g/L of complexing agent, 0.1-1% of thiourea, 0.2-1.5% of surfactant and 6.5-7.5 of pH; wherein the surfactant is at least one of sodium cholate, sodium deoxycholate, sodium taurodeoxycholate and sodium chenodeoxycholate.

2. The kit of claim 1, wherein the buffer is one of Good's buffer, Tris buffer and phosphate buffer.

3. The matrix metalloproteinase-3 assay kit as claimed in claim 1, wherein the preservative is at least one of sodium azide, PC300, CAA.

4. The matrix metalloproteinase-3 assay kit as defined in claim 1, wherein the inorganic salt is at least one of sodium chloride and potassium chloride.

5. The kit for detecting matrix metalloproteinase-3 as claimed in claim 1, wherein the complexing agent is at least one of EDTA-2Na, dimercaprol, sodium dimercaptopropane sulfonate, mercaptoethylamine, thioglycolic acid, thiourea, ammonium fluoride, 8-hydroxyquinoline, potassium chromate and sodium sulfide.

6. The matrix metalloproteinase-3 assay kit as claimed in claim 1, wherein the kit further comprises reagent R2, the reagent R2 comprises: 60-120 nm, polystyrene carboxyl microspheres with the final concentration of 0.25-0.4%, buffer solution with the final concentration of 20-50 mM, EDC with the concentration of 0.75-1%, matrix metalloproteinase-3 polyclonal antibody with the final concentration of 20-25 ml/L, a blocking agent and R2 buffer solution, wherein the blocking agent is a mixture of BSA with the concentration of 18-20% and glycine with the concentration of 0.8-1.2 mol/L; the R2 buffer solution comprises 50 mM-100 mM buffer solution, 4% -6% protective agent and 0.095% -0.1% preservative.

7. The matrix metalloproteinase-3 assay kit of claim 6, wherein the protectant is at least one of sucrose, trehalose, glucose, BSA, mannitol, ethylene glycol, glycerol; the preservative is at least one of sodium azide, PC300 and CAA.

8. The matrix metalloproteinase-3 assay kit of claim 1, wherein the kit further comprises a matrix metalloproteinase-3 calibrator with different concentration gradients.

9. The kit of claim 8, wherein the matrix metalloproteinase-3 calibrator comprises matrix metalloproteinase-3 and a matrix solution comprising at least one of phosphate buffer, disodium or dipotassium EDTA, sodium citrate, sodium or lithium heparin, urea, uric acid, trehalose, BSA, salts, and potassium chloride.

10. A method for preparing a matrix metalloproteinase-3 assay kit, which is prepared by using the formulation of any one of claims 1 to 9.

Technical Field

The invention relates to the technical field of biology, in particular to a matrix metalloproteinase-3 determination kit and a preparation method thereof.

Background

Matrix metalloproteinases (matrix metalloproteinases), a large family of matrix metalloproteinases, require Ca for their availability²⁺、Zn²⁺Plasma metal ions are known as cofactors. The family members have similar structures and generally consist of 5 functionally distinct domains: (1) a hydrophobic signal peptide sequence; (2) the main function of the propeptide region is to stabilize the proenzyme. When the region is cut off by exogenous enzyme, the MMPs zymogen is activated; (3) the catalytic active region has a zinc ion binding site and is crucial to the exertion of the catalytic action of the enzyme; (4) a proline-rich hinge region; (5) the carboxy-terminal region, which is related to the substrate specificity of the enzyme. Wherein the enzyme-catalytically active region and the propeptide region are highly conserved. Members of MMPs have characteristics based on the above structures. Various MMPs have some substrate specificity among themselves, but not absolutely. The same MMP degrades various extracellular matrix components, and one extracellular matrix component can be degraded by various MMPs, but the degradation efficiency of different enzymes can be different.

MMPs are classified into 6 types, collagenase, gelatinase, stromelysin, furin-activated MMPs and other secreted MMPs. Matrix metalloproteinase 3 is an important member of matrix metalloproteinase family, MMP-3 is mainly secreted by macrophage, synovial cell, fibroblast and chondrocyte, is a protease with a wide range of substrates, the activity of the protease can lead to the decomposition of proteins (enzymes) such as fibronectin, cartilage connexin and various collagenases (including IV, VII, IX and XI), the protease is considered as the most important protease for explaining articular cartilage, is involved in a series of physiological and pathological processes such as histomorphogenesis, injury repair and inflammatory reaction, and plays an important role in the occurrence and the progression of diseases such as rheumatoid arthritis, atherosclerosis and breast cancer and tumors.

MMP-3 is also known as mesenchyme. A variety of cells can express MMP-3 when appropriately stimulated, such as fibroblasts, chondrocytes, endothelial cells, macrophages, vascular smooth muscle cells, osteoblasts, keratinocytes, and the like. Inflammatory factors such as IL-1, tumor necrosis factor, epidermal growth factor, platelet derived growth factor, phorbol, and the like are all inducing agents. Retinoic acid, glucocorticoids, estrogens, progesterone and TGF-beta all inhibit MMP-3 expression. MMP-3, also known as stromelysin-1, is one of the major members of the metalloproteases, MMP-3 is synthesized intracellularly in the form of a precursor (proMMP23), containing a total of 477 amino acids and having a molecular weight of about 57 kDa.

The MMP-3 is usually measured by adopting an ELISA method, but the ELISA operation steps are complex, the reaction factors are more influenced, particularly, the coating of a solid phase carrier is difficult to achieve the consistency among individuals, the range of a standard curve is generally wider in the sandwich ELISA method for measuring the high molecular weight substances, the detection result difference of different batches of reagents is larger, and the accuracy and the sensitivity are not high.

Therefore, how to develop a matrix metalloproteinase-3 assay kit with high accuracy and sensitivity is a technical problem to be solved urgently.

Disclosure of Invention

The invention aims to provide a matrix metalloproteinase-3 determination kit, which improves the sensitivity of a reagent and has good accuracy, linearity and precision performance.

In order to achieve the above object, the present invention provides a matrix metalloproteinase-3 assay kit, comprising a reagent R1, wherein the reagent R1 comprises the following components in parts by mass:

100 mmol/L-200 mmol/L of buffer solution, 0.1-0.2% of preservative, 1-10% of inorganic salt, 0.2-0.8 g/L of complexing agent, 0.1-1% of thiourea, 0.2-1.5% of surfactant and 6.5-7.5 of pH; wherein the surfactant is at least one of sodium cholate, sodium deoxycholate, sodium taurodeoxycholate and sodium chenodeoxycholate.

Further, the buffer solution is one of Good's buffer solution, Tris buffer solution and phosphate buffer solution.

Further, the preservative is at least one of sodium azide, PC300 and CAA.

Further, the inorganic salt is at least one of sodium chloride and potassium chloride.

Further, the complexing agent is at least one of EDTA-2Na, dimercaptopropanol, sodium dimercaptopropane sulfonate, mercaptoethylamine, thioglycolic acid, thiourea, ammonium fluoride, 8-hydroxyquinoline, potassium chromate and sodium sulfide.

Further, the kit also comprises a reagent R2, and the components of the reagent R2 comprise: 60-120 nm, polystyrene carboxyl microspheres with the final concentration of 0.25-0.4%, buffer solution with the final concentration of 20-50 mM, EDC with the concentration of 0.75-1%, matrix metalloproteinase-3 polyclonal antibody with the final concentration of 20-25 ml/L, a blocking agent and R2 buffer solution, wherein the blocking agent is a mixture of BSA with the concentration of 18-20% and glycine with the concentration of 0.8-1.2 mol/L; the R2 buffer solution comprises 50 mM-100 mM buffer solution, 4% -6% protective agent and 0.095% -0.1% preservative.

Further, the protective agent is at least one of sucrose, trehalose, glucose, BSA, mannitol, ethylene glycol and glycerol; the preservative is at least one of sodium azide, PC300 and CAA.

Further, the kit also comprises matrix metalloproteinase-3 calibrators with different concentration gradients.

Further, the matrix metalloproteinase-3 calibrator comprises matrix metalloproteinase-3 and a matrix solution, wherein the matrix solution comprises at least one of phosphate buffer, disodium EDTA or dipotassium EDTA, sodium citrate, sodium heparin or lithium heparin, urea, uric acid, trehalose, BSA, salt substances and potassium chloride.

The invention also provides a preparation method of the matrix metalloproteinase-3 determination kit, which is prepared by adopting the formula.

One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:

when the matrix metalloproteinase-3 determination kit provided by the invention is used for latex immunoturbidimetry testing, the steric hindrance of the combination of the matrix metalloproteinase-3 and the matrix metalloproteinase-3 antibody coupled on the latex microspheres can be reduced by adding 0.1-1% of thiourea and 0.2-1.5% of surfactant (at least one of sodium cholate, sodium deoxycholate, sodium taurodeoxycholate and sodium chenodeoxycholate), and the sensitivity of the reagent can be greatly improved in the low-content sample test of the matrix metalloproteinase-3, and meanwhile, the kit has good accuracy, linearity and precision performance.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on the drawings without creative efforts.

FIG. 1 is a calibration graph of a matrix metalloproteinase-3 assay kit provided in example 1 of the present invention.

Detailed Description

The present invention will be described in detail below with reference to specific embodiments and examples, and the advantages and various effects of the present invention will be more clearly apparent therefrom. It will be understood by those skilled in the art that these specific embodiments and examples are for the purpose of illustrating the invention and are not to be construed as limiting the invention.

Throughout the specification, unless otherwise specifically noted, terms used herein should be understood as having meanings as commonly used in the art. Accordingly, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. If there is a conflict, the present specification will control.

Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment and the like used in the present invention are commercially available or can be obtained by an existing method.

In order to solve the technical problems, the general idea of the embodiment of the application is as follows:

according to a typical embodiment of the present invention, there is provided a matrix metalloproteinase-3 assay kit, comprising a reagent R1, wherein the reagent R1 comprises the following components in parts by mass:

100 mmol/L-200 mmol/L of buffer solution, 0.1-0.2% of preservative, 1-10% of inorganic salt, 0.2-0.8 g/L of complexing agent, 0.1-1% of thiourea, 0.2-1.5% of surfactant and 6.5-7.5 of pH; wherein the surfactant is at least one of sodium cholate, sodium deoxycholate, sodium taurodeoxycholate and sodium chenodeoxycholate.

The structure of MMP-3 proteins can be divided into an amino terminal propeptide region, an amino terminal catalytic region, and a carboxy terminal domain 3 portion. A signal sequence consisting of 17 amino acid residues is present in the front of the amino-terminal propeptide region, which can direct newly synthesized MMP-3 to move toward the cell membrane. The amino-terminal catalytic region is connected to the amino-terminal propeptide region by a hinge region and contains a Zn in its structure²⁺The motif is the active site of the whole protease. The amino acid sequence of the carboxy terminal domain is very similar to that of the hemopexin, and is the site where MMP-3 binds to the substrate. Zn in its catalytic zone²⁺The amino-terminal unpaired cysteine was coordinately bound and its catalytic activity was not revealed. When this coordination bond is broken, the pro-peptide region of the protease is hydrolyzed and the protein conformation changes, which opens up the protein conformation of matrix metalloproteinase-3, as we tested by latex immunoturbidimetry, by adding thiourea: 0.1-1 percent of surfactant (at least one of sodium cholate, sodium deoxycholate, sodium taurodeoxycholate and sodium chenodeoxycholate) and 0.2-1.5 percent of surfactant can reduce the steric hindrance of the combination of the matrix metalloproteinase-3 and the matrix metalloproteinase-3 antibody coupled on the latex microsphere, greatly improve the sensitivity of the reagent in the test of low-content samples of the matrix metalloproteinase-3 and simultaneously have good accuracy, linearity and precision performance.

If the mass fraction of the thiourea is less than 0.1% or the mass fraction of the surfactant is less than 0.2%, the change of the MMP-3 protein conformation is not enough, and the purpose of improving the sensitivity of the reagent is not achieved; if the mass fraction of the thiourea is more than 1% or the mass fraction of the surfactant is more than 1.5%, the MMP-3 protein conformation is seriously changed, even denatured and inactivated, and the purpose of improving the sensitivity of the reagent cannot be achieved.

The reason why the surfactant is selected from at least one of sodium cholate, sodium deoxycholate, sodium taurodeoxycholate and sodium chenodeoxycholate is that: the four substances can be used for dissolving protein, and any one of the four substances is combined with thiourea to achieve the aims of developing MMP-3 protein conformation and improving reagent sensitivity.

When the surfactant is a plurality of sodium cholate, sodium deoxycholate, sodium taurodeoxycholate and sodium chenodeoxycholate, the proportion of the surfactants is not limited, and the total amount is 0.2-1.5%.

Thiourea 0.1-1% and surfactant 0.2-1.5% are combined, so that the conformation of matrix metalloproteinase-3 protein in the sample is changed, and the steric hindrance of the combination of the protein and the antibody coupled on the latex microsphere is reduced, thereby greatly improving the sensitivity of the reagent and having good accuracy, linearity and precision performance. The lack of thiourea, either of the surfactants, does not solve the above technical problem.

As an alternative embodiment, the buffer is one of Good's buffer, Tris buffer, phosphate buffer.

As an alternative embodiment, the preservative is at least one of sodium azide, PC300, CAA.

As an alternative embodiment, the inorganic salt is at least one of sodium chloride and potassium chloride.

As an alternative embodiment, the complexing agent is at least one of EDTA-2Na, dimercaprol, sodium dimercaptopropane sulfonate, mercaptoethylamine, mercaptoacetic acid, thiourea, ammonium fluoride, 8-hydroxyquinoline, potassium chromate, and sodium sulfide.

As an alternative embodiment, the kit further comprises a reagent R2, and the components of the reagent R2 comprise: 250 nm-350 nm, polystyrene carboxyl microspheres with the final concentration of 0.25-0.4%, buffer solution with the final concentration of 20 mM-50 mM, EDC with the concentration of 0.75-1%, matrix metalloproteinase-3 polyclonal antibody with the final concentration of 20 ml/L-25 ml/L, a blocking agent and R2 buffer solution, wherein the blocking agent is a mixture of BSA with the concentration of 18-20% and glycine with the concentration of 0.8 mol/L-1.2 mol/L; the R2 buffer solution comprises 50 mM-100 mM buffer solution, 4% -6% protective agent and 0.095% -0.1% preservative. The protective agent is at least one of sucrose, trehalose, glucose, BSA, mannitol, ethylene glycol and glycerol; the preservative is at least one of sodium azide, PC300 and CAA.

As an alternative embodiment, the kit further comprises a matrix metalloproteinase-3 calibrator in different concentration gradients. The matrix metalloproteinase-3 calibrator comprises matrix metalloproteinase-3 and a matrix solution, wherein the matrix solution comprises at least one of phosphate buffer solution, disodium EDTA or dipotassium EDTA, sodium citrate, sodium heparin or lithium heparin, urea, uric acid, trehalose, BSA, salt substances and potassium chloride.

The concentration gradient of the matrix metalloproteinase-3 in the matrix metalloproteinase-3 calibrator is as follows: 0.0, 125.0ng/mL, 250.0ng/mL, 500.0ng/mL, 1000.0ng/mL, 2000.0 ng/mL.

The calibration curve of the matrix metalloproteinase-3 calibrator is shown in FIG. 1.

According to an exemplary embodiment of the present invention, a method for preparing a matrix metalloproteinase-3 assay kit is provided, which is prepared by using the formulation.

The detection principle of the matrix metalloproteinase-3 determination kit provided by the invention is as follows:

the immunoturbidimetry is characterized in that soluble antigen and antibody are specially combined in a liquid phase to generate a compound with a certain size to form refraction or absorption of light, transmitted light or scattered light after the refraction or the absorption is measured to be used as a calculation unit, and the absorbed transmitted light is used as the calculation unit. Under the condition of excessive antigen, the antigen-antibody reaction is carried out on the antigen-antibody complex and corresponding Ig in a sample to be detected to form a soluble complex, the turbidity of a reaction medium is changed, the absorbed amount is measured by utilizing a spectrophotometer, the reading value is expressed by an absorption unit (A) or an OD value, the antigen content in the sample to be detected is in direct proportion to the absorbance, and the Ig content in the object to be detected can be calculated through a standard curve.

Reagent R1: the sample treatment solution is mainly used for diluting a sample, simultaneously treating background interference in the sample and improving the accuracy of a detection result, and the reagent R1 is optimized, so that the determination of a medium-low value sample can be accurately and effectively improved on the premise of not influencing the sensitivity of the reagent.

Reagent R2: the core reaction component comprises common components such as latex microsphere particles coated with the antibody, a surfactant, a preservative and the like.

Calibrating material/quality control material: the quality control of the reagent before testing is mainly carried out, and the reagent is usually in a liquid or dry powder state. For obtaining a standard curve.

The use method of the matrix metalloproteinase-3 determination kit comprises the following steps:

testing a matrix metalloproteinase-3 kit by using a full-automatic biochemical analyzer, wherein the parameters are as follows, firstly adding 2.4ul of a sample under the dominant wavelength of 570nm, then adding 120ul of a reagent 1, incubating at 37 ℃ for about 5min, adding 40ul of a reagent 2, reading absorbance A1 for about 30s, reading absorbance A2 after about 4min, and calculating the difference delta A of the absorbance, namely A2-A1; and (3) carrying out multi-point calibration by using a matched calibrator to obtain a calibration curve and carrying out linear fitting, wherein the sample concentration (unit ng/mL) can be calculated on the calibration curve through the detected absorbance difference.

The method for preparing the matrix metalloproteinase-3 assay kit of the present application will be described in detail below with reference to examples, comparative examples and experimental data.

S1, examples, R2 reagents for each comparative example were prepared as follows:

(1) preparation of solutions

Activating buffer: 10-50mmol/L HEPES buffer solution, pH value is 6.0-7.0.

② coupling buffer solution: 10-50mmol/L HEPES buffer solution, pH value is 7.0-8.0.

Activating agent: 10mg/ml EDC, which is ready for use.

Sealing liquid: 10% -20% BSA.

R2 buffer: 25-50mmol/L HEPES, 0.5g/L EDTA-2Na, 5% ethylene glycol, 5% glucose, 0.1% PC-300, pH 7.0-7.5.

(2) Preparation of latex reagent R2

Mixing 10mL of latex microspheres with the particle size of 250-350nm and an activation buffer solution according to the volume ratio of 1:2-1:4, and then uniformly mixing;

adding 2-3mL of 10mg/mL activating agent into the step I, uniformly mixing, placing the mixture in a constant-temperature shaking table for reacting for 20-30min, wherein the temperature range is as follows: 30-37 ℃;

③ diluting the antibody to 1mg/mL by using a coupling buffer solution, adding 50-100mL of the diluted antibody of 1mg/mL into the step (II), uniformly mixing, placing the mixture in a constant temperature shaking table for reacting for 2-3h, wherein the temperature range is as follows: 30-37 ℃;

adding 5-10mL of confining liquid into the step (III), uniformly mixing, and placing the mixture in a constant temperature shaking table for reacting for 0.5-1h, wherein the temperature range is as follows: 30-37 ℃;

fifthly, adding 200 and 250mL of R2 buffer solution into the step (IV), and uniformly mixing for later use.

The formula of S2, examples, R1 reagent for each comparative example is shown in Table 1.

TABLE 1

S3, each embodiment and each proportion of matrix metalloproteinase-3 calibrator comprise matrix metalloproteinase-3 and matrix liquid, wherein the matrix liquid comprises at least one of phosphate buffer, EDTA disodium or EDTA dipotassium, sodium citrate, heparin sodium or heparin lithium, urea, uric acid, trehalose, BSA, salt substances and potassium chloride.

Test examples

Performance evaluations were performed using the various examples and comparative matrix metalloproteinase-3 assay kits:

1. evaluation of sensitivity: measuring blank samples and low-concentration samples with MMP-3 concentration of 5ng/mL, 10ng/mL and 15ng/mL, measuring each sample for 10 times, calculating a mean value, a standard deviation, a deviation and a variation coefficient, wherein the CV is less than 10% and the deviation is less than 10% so as to meet the use requirement; the results are shown in Table 2.

TABLE 2 sensitivity data for examples 1-4 and comparative examples 1-6

For comparison, the mean, deviation, standard deviation SD, CV statistics of 5ng/mL samples in Table 1 are shown in Table 3.

TABLE 3

Group of	Mean value (ng/mL)	Deviation (%)	Standard deviation SD (ng/mL)	CV(％)
					Comparative example 1	5.06	1.2	0.272	5.37
Comparative example 2	5.19	3.8	0.251	4.84
					Comparative example 3	5.24	4.8	0.263	5.03
Comparative example 4	5.27	5.4	0.125	2.38
					Comparative example 5	4.18	-16.4	1.704	40.77
Comparative example 6	3.59	-28.2	1.320	36.78
					Comparative example 7	4.36	-12.8	1.029	23.59
Comparative example 8	4.37	-12.6	1.333	30.49
					Example 1	3.72	-25.6	1.188	31.93
Example 2	4.04	-19.2	1.217	30.12
					Example 3	4.23	-15.4	0.906	21.41
Example 4	4.32	-13.6	1.016	23.5

2. The accuracy evaluation results are shown in table 4.

TABLE 4 accuracy data

3. The linear range is shown in table 5.

TABLE 5 Linear Range data

4. Precision: samples were taken and tested 10 times, and the precision CV was calculated and the results are shown in Table 6.

TABLE 6 precision evaluation data

As can be seen from the data in tables 3 to 6:

in comparative example 1, sodium taurodeoxycholate was not contained, the sensitivity was not 15ng/mL, the accuracy was 6.70% and 3.99%, and the precision CV value was 7.008%;

in comparative example 2, without thiourea, the sensitivity was not up to 15ng/mL, the accuracy was-7.00% and-5.25%, and the precision CV value was 6.669%;

in comparative example 3, the mass fraction of thiourea was 0.05%, which is lower than the range of 0.1% to 1% of the present invention, the sensitivity was not up to 15ng/mL, the accuracy was 0.40% and 4.75%, and the precision CV value was 7.170%;

in comparative example 4, the mass fraction of thiourea is 2%, which is higher than the range of 0.1% -1% of the present invention, the sensitivity does not reach 15ng/mL, the accuracy is 1.20% and 3.30%, and the precision CV value is 6.076%;

in the comparative example 5, the mass fraction of the sodium taurodeoxycholate is 0.1%, which is lower than the range of 0.2% -1.5% of the invention, the sensitivity is not up to 15ng/mL, the accuracy is 1.90% and 5.14%, and the precision CV value is 7.027%;

in the comparative example 6, the mass fraction of the sodium taurodeoxycholate is 2%, which is higher than the range of 0.2% -1.5% of the invention, the sensitivity is not up to 15ng/mL, the accuracy is-2.13% and-6.29%, and the precision CV value is 6.738%;

in comparative example 7, the solution containing thiourea and sodium taurodeoxycholate was changed to the commonly used surfactant Tween, the sensitivity was not 15ng/mL, the accuracy was-5.17% and-2.14%, and the precision CV value was 6.688%;

in the comparative example 8, the sodium taurodeoxycholate does not contain thiourea, and the sodium taurodeoxycholate is changed into the common surfactant Tween, the sensitivity does not reach 15ng/mL, the accuracy is-9.70% and-4.07%, and the precision CV value is 6.676%; the result shows that 0.1 to 1 percent of thiourea has no synergistic interaction with other commonly used surfactants such as Tween, and the sensitivity, the accuracy and the precision are not obviously improved.