Test paper for detecting oestrone and preparation method thereof

Abstract

The preparation method comprises the following steps: (1) preparing a CsYF4 (at) Yb2O3 compound, and adsorbing an oestrone antibody, namely a primary antibody, on the surface of the compound to obtain a photothermal signal probe; (2) assembling the test strip, and respectively fixing an oestrone antigen and a secondary antibody on the detection area and the quality control area; (3) mixing the photo-thermal signal probe with a to-be-detected sample solution, and inserting the sample pad end of the test strip into the mixed solution for chromatography; and (4) detecting a photo-thermal signal: irradiating the detection area by using a near-infrared LED, collecting the temperature by using thermal imaging or temperature measuring equipment, and carrying out quantitative analysis according to the linear relationship between the temperature of the detection area and the concentration of the sample oestrone. The detection mode is flexible, the linear range is wide, the sensitivity is high, and the specificity is good.

Description

Technical Field

[0001] The invention relates to the technical field of small molecule analysis and detection, and in particular to a test paper for detecting estrone and a preparation method thereof. Background Art

[0002] Lateral flow immunochromatographic test strips (LFIA) have the characteristics of fast analytical performance, good selectivity, low cost, small sample volume requirement, easy large-scale production and stable long-term storage, and are widely used in the design of portable analytical detection sensors. The photothermal lateral flow immunochromatographic test strips (LFIA) used as photothermal signal probes in LFIA have increased sensitivity by dozens to hundreds of times compared with the colorimetric mode. The signal of this type of detection method is caused by temperature changes due to the photothermal effect, with low background signals and sensitive sensing. It can be performed on various substrates of different colors and has great application potential. At present, new nanomaterials with higher photothermal conversion efficiency are still needed as photothermal signal probes to form more obvious thermal contrast, so as to further improve the performance of photothermal LFIA.

[0003] Fluorides generally have lower phonon energy and higher light transmittance, which is beneficial to reduce light scattering and improve light utilization. In terms of photothermal conversion, the fluoride matrix may help absorb and convert photons, thereby improving photothermal efficiency. Yb2O3 is a rare earth oxide with excellent thermal and chemical stability. In the field of optics, Yb2O3 is often used as an additive for optical materials to improve the light transmittance and photothermal conversion efficiency of the material. Summary of the invention

[0004] In view of the above problems existing in the prior art, the present invention provides a test paper for detecting estrone and a preparation method thereof. The CsYF4@Yb2O3 composite material is used to prepare a photothermal test paper strip for detecting estrone. The test paper strip of the present invention is used to detect estrone, and the detection limit is as low as 10 -1 pg / mL.

[0005] The technical solution of the present invention is as follows:

[0006] The first object of the present invention is to provide a CsYF4@Yb2O3 composite material, wherein the preparation method of the composite material comprises the following steps:

[0007] (1) Y(NO3)3 and Yb2O3 are mixed in an ethylenediaminetetraacetic acid aqueous solution, and NH4F solution and CsF solution are added in sequence under stirring, and stirring is continued until a milky white solution is produced;

[0008] (2) The milky white solution is placed at high temperature for reaction, cooled to room temperature after the reaction is completed, washed and dried to obtain the CsYF4@Yb2O3 composite material.

[0009] In one embodiment of the present invention, in step (1), one or more of the following conditions are met:

[0010] The molar ratio of Y(NO3)3 to Yb2O is 1:10-10:1;

[0011] The concentration of the EDTA aqueous solution is 5-7 mg / mL;

[0012] The concentration of NH4F solution is 0.8-1.2 mol / L;

[0013] The concentration of CsF solution is 0.8-1.2 mol / L;

[0014] The molar ratio of Y(NO3)3 to CsF is 1:5-5:1;

[0015] The stirring reaction conditions are room temperature and time 5-30 min.

[0016] In one embodiment of the present invention, in step (2), one or more of the following conditions are met:

[0017] The temperature of the high temperature reaction is 160-250°C and the time is 12-36h;

[0018] Clean with ultrapure water and alcohol alternately 2-3 times;

[0019] Drying is performed at 50-80°C for 1-4 hours.

[0020] In one embodiment of the present invention, the specific method of the CsYF4@Yb2O3 composite material is as follows: 140-160 mg of ethylenediaminetetraacetic acid EDTA is added to a 50 mL beaker, and 25 mL of ultrapure water is added and stirred rapidly for 5 minutes. Then, 0.8-1.0 mL of Y(NO3)3 with a molar concentration of 0.6-0.8 mol / L and 0.1-0.3 mL of Yb2O3 aqueous solution (containing 5% nitric acid) with a molar concentration of 0.6-0.8 mol / L are added and stirred rapidly for 30 minutes. Subsequently, 2-4 mL of NH4F with a molar concentration of 0.8-1.2 mol / L and 2-4 mL of CsF with a molar concentration of 0.8-1.2 mol / L are added, and stirred continuously for 30 minutes until a milky white solution is produced. After the solution was transferred to a 200°C autoclave, the reaction was continued for 24 h, and then cooled to room temperature, washed with ultrapure water and alcohol alternately for 2-3 times, and dried at 70°C for 2 h to obtain the CsYF4@Yb2O3 nanocomposite material. The solution was dried for further use.

[0021] The second object of the present invention is to provide an application of the above-mentioned CsYF4@Yb2O3 composite material for preparing a photothermal signal probe.

[0022] The third object of the present invention is to provide a photothermal signal probe prepared from the above-mentioned CsYF4@Yb2O3 composite material, which contains CsYF4@Yb2O3 composite material, estrone antibody and bovine serum albumin.

[0023] In one embodiment of the present invention, the method for preparing the photothermal signal probe is as follows: a CsYF4@Yb2O3 composite material is mixed with a test antibody and bovine serum albumin to obtain a CsYF4@Yb2O3-mAb mixed solution.

[0024] In one embodiment of the present invention, a CsYF4@Yb2O3 composite material is placed in a centrifuge tube, a weak alkaline solution is added to adjust the pH of the system to 6-8, the mixture is shaken and mixed, and then an estrone antibody is added. After the mixture is shaken for 30-60 minutes at room temperature, bovine serum albumin (BSA) is added for blocking, and the mixture is shaken for 1-1.5 hours at room temperature. After centrifugation, the supernatant is removed, and the remaining material is redissolved in a buffer solution to obtain a CsYF4@Yb2O3-mAb mixed solution, which is refrigerated for later use.

[0025] In one embodiment of the present invention, the buffer is a phosphate buffer, a borate buffer or a carbonate buffer.

[0026] A fourth object of the present invention is to provide a test strip containing the above-mentioned photothermal signal probe, wherein the test strip comprises the photothermal signal probe and a test strip body;

[0027] The photothermal signal probe is prepared by modifying a CsYF4@Yb2O3 composite material with an estrone monoclonal or polyclonal antibody, and is used in a form independent of the main structure of the photothermal test strip or in a form dried on a conjugate pad;

[0028] The test strip body comprises a PVC bottom plate, a sample pad, a nitrocellulose membrane (NC membrane), and an absorption pad.

[0029] In one embodiment of the present invention, the test strip body comprises: a sample pad, a nitrocellulose membrane, i.e., an NC membrane, and an absorption pad are overlapped and pasted in sequence from top to bottom in a horizontal direction on a PVC bottom plate; wherein the nitrocellulose membrane is used to separate and detect analytes from other substances in the sample, the sample pad is used for loading samples, the absorption pad is used to absorb excess liquid, and the PVC bottom plate provides physical support for the test strip; the nitrocellulose membrane includes a detection area, i.e., a T area, and a quality control area, i.e., a C area; wherein, an estrogen antigen, i.e., a molecule-protein conjugate to be tested, is fixed on the T area; and a secondary antibody is fixed on the C area, and the secondary antibody is a secondary antibody directed against the source of the primary antibody, i.e., an anti-primary antibody;

[0030] The photothermal signal probe is used in a form independent of the main structure of the photothermal test strip, or the photothermal signal probe is dried on a conjugate pad and the conjugate pad is inserted between the sample pad and the NC membrane for use.

[0031] In one embodiment of the present invention, the source of the estrone antibody, ie, the primary antibody, includes at least one of mouse, rat, and rabbit.

[0032] In one embodiment of the present invention, the secondary antibody comprises at least one of goat anti-mouse secondary antibody, rabbit anti-mouse secondary antibody, goat anti-rabbit secondary antibody and donkey anti-rabbit secondary antibody.

[0033] A fifth object of the present invention is to provide a method for preparing the above-mentioned test strip, comprising the following steps:

[0034] Preparation of CsYF4@Yb2O3 composite materials;

[0035] preparing a CsYF4@Yb2O3 composite material, estrone antibody, and a CsYF4@Yb2O3-mAb mixture of bovine serum albumin;

[0036] Construct the test strip: drip or spray estrogen antigen on the T area, drip or spray the secondary antibody against the source of the primary antibody on the C area, i.e., the anti-primary antibody, and store them in a vacuum bag after drying for future use;

[0037] The photothermal signal probe, i.e., the CsYF4@Yb2O3-mAb mixed solution, is stored in a sealed container in the form of a solution or a lyophilized powder; or the photothermal signal probe, i.e., the CsYF4@Yb2O3-mAb mixed solution, is dried on a conjugate pad and the conjugate pad is inserted between the sample pad and the NC membrane for use.

[0038] In one embodiment of the present invention, the T zone is dripped or sprayed with an estrone antigen, specifically: a 5-20 mM PBS solution containing 0.5-10 mg / mL estrone antigen is dripped or sprayed on the T zone; the C zone is dripped or sprayed with a secondary antibody directed against the source of the primary antibody, i.e., an anti-primary antibody, specifically: a 5-20 mM PBS solution containing 0.05-10 mg / mL secondary antibody is dripped or sprayed on the C zone.

[0039] The sixth object of the present invention is to provide an application of the above-mentioned test strip for detecting estrone; the photothermal temperature of the detection zone is negatively correlated with the estrone content to be detected, and the color intensity is negatively correlated with the estrone content in the sample, specifically:

[0040] When the sample does not contain estrone, the T zone appears purple and the temperature is high;

[0041] When the sample contains estrone, the T zone appears light purple or even disappears, and the temperature decreases;

[0042] The quality control area serves as a reference for verifying the validity of the test paper results and always appears purple.

[0043] A sixth object of the present invention is to provide a test strip for detecting estrone, comprising a photothermal signal probe and a test strip body;

[0044] The photothermal signal probe includes a mixture of CsYF4@Yb2O3 composite material, estrone antibody (i.e. primary antibody), and bovine serum albumin, i.e. CsYF4@Yb2O3-mAb mixed solution;

[0045] The test strip body comprises: a sample pad, a nitrocellulose membrane, namely, an NC membrane, and an absorption pad are overlapped and pasted in sequence from top to bottom in the horizontal direction on a PVC bottom plate; wherein the nitrocellulose membrane is used to separate and detect the analyte from other substances in the sample, the sample pad is used for loading the sample, and the absorption pad is used to absorb excess liquid, and the PVC bottom plate provides physical support for the test strip; the nitrocellulose membrane includes a detection area, namely, a T area, and a quality control area, namely, a C area; wherein, an estrogen antigen, namely, a molecule-protein conjugate to be tested, is fixed on the T area; and a secondary antibody is fixed on the C area, and the secondary antibody is a secondary antibody directed against the source of the primary antibody, namely, an anti-primary antibody;

[0046] The photothermal signal probe is used in a form independent of the main structure of the photothermal test strip, or the photothermal signal probe is dried on a conjugate pad and the conjugate pad is inserted between the sample pad and the NC membrane for use.

[0047] In one embodiment of the present invention, the method for detecting estrone with a test strip comprises the following steps:

[0048] When the photothermal signal probe is used in a form independent of the main structure of the photothermal test strip, it specifically includes:

[0049] The sample to be tested and the CsYF4@Yb2O3-mAb solution are placed in a running buffer and mixed for 3-10 minutes, and then placed in the test strip; after 15-30 minutes, the colorimetric result is read and semi-quantitative analysis is performed; a colorimetric result photo is obtained, and grayscale analysis is performed using image processing software for quantitative analysis;

[0050] When the photothermal signal probe is dried on the conjugate pad and the conjugate pad is inserted between the sample pad and the NC film of the test paper main structure for use, the method specifically includes:

[0051] The sample to be tested is mixed with the running buffer solution, and placed in the test strip. After 20-40 minutes, the colorimetric result is read, and a colorimetric result photo is obtained for semi-quantitative analysis. Grayscale analysis is performed using image processing software for quantitative analysis.

[0052] After the test strip is dried, it is placed under a near-infrared LED light source for excitation, and the temperature result is obtained using a thermal imaging or temperature measuring device and an intelligent display terminal. The thermal imaging or temperature measuring device includes at least one of a mobile phone infrared thermal imaging analysis accessory, an infrared thermal imager, and a temperature measuring gun. The intelligent display terminal includes at least one of a computer and a smart phone. The thermal imaging device collects photothermal imaging photos and outputs and displays them through the intelligent display terminal connected thereto.

[0053] In one embodiment of the present invention, the running buffer is a PBS solution with a pH of 6.5 to 8.0 and a total concentration of 10 mM, and the following components are contained in mass percentages, specifically comprising: 0 to 15% sucrose, 1 to 10% BSA, and 0.15 to 1% Tween-20.

[0054] In one embodiment of the present invention, the wavelength of the near-infrared LED light source is 980 nm.

[0055] The detection principle of the photothermal test strip for detecting estrone of the present invention is as follows: the quality control area (area C) is used as a reference to verify the validity of the test strip results, and it always appears purple. After the sample solution and CsYF4@Yb2O3-mAb are pre-mixed, they move toward the absorbent paper under capillary action. When there is no estrone in the sample, CsYF4@Yb2O3-mAb is captured by estrone-BSA in the T area, and the T area is visible to the naked eye as purple. Under the excitation of the laser, CsYF4@Yb2O3-mAb produces an LSPR effect, and the temperature rises. Excess CsYF4@Yb2O3-mAb will be captured by the secondary antibody in the C area, so that the C area also appears purple; when the sample contains estrone, estrone combines with part of the CsYF4@Yb2O3-mAb, thereby reducing the total amount of CsYF4@Yb2O3-mAb captured in the T area, and the LSPR effect of the CsYF4@Yb2O3-mAb in the T area is reduced or even disappears, and the temperature drops. As the concentration of estrone in the sample increases, less and less CsYF4@Yb2O3-mAb is captured in the T zone, and the temperature of the T zone gradually decreases, which is inversely proportional to the analyte concentration.

[0056] The beneficial technical effects of the present invention are:

[0057] The CsYF4@Yb2O3 composite material provided by the present invention is used in the preparation and application of photothermal test strips. There is no need to change the conventional structure of the test strips. It can be used as a photothermal signal probe and can be used independently of the photothermal test strips for convenient storage, or it can be fixed on the binding pad of the test strip for easy carrying.

[0058] The detection method provided by the present invention includes a photothermal test strip. The photothermal test strip for detecting estrone is based on the plasma resonance effect, uses a CsYF4@Yb2O3 composite material with high photothermal conversion efficiency and microsize as a T-zone fixed photothermal signal probe, is excited by a near-infrared LED light source, and is combined with an intelligent terminal and infrared thermal imaging accessories to realize the collection of photothermal signals, effectively remove the base color of the sample liquid and the fluorescent background interference of the test strip, thereby improving the signal-to-noise ratio.

[0059] The inspection method provided by the present invention has a lower detection limit, a wider detection range and better specificity, is more sensitive than other photothermal detection test strips, and is suitable for the rapid detection of estrone. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 This is a schematic diagram of the photothermal test strip of the present invention;

[0061] Figure 2 The scanning electron microscope image and particle size distribution diagram of the CsYF4@Yb2O3 composite material in the photothermal signal probe of the test strip of the present invention;

[0062] Figure 3 The photothermal temperature change of CsYF4@Yb2O3 composite material, CsYF4 and Yb2O3 in the photothermal signal probe of the test strip of the present invention;

[0063] Figure 4 The response of the test strip of the present invention to water samples with different concentrations of estrone in the photothermal mode;

[0064] Figure 5 The figure shows the response of the test strip of the present invention to estrogen and four other estrogens. DETAILED DESCRIPTION

[0065] The present invention is described in detail below in conjunction with the accompanying drawings and embodiments.

[0066] Example 1 Preparation of raw materials

[0067] 1.1 Preparation of CsYF4@Yb2O3 nanocrystals

[0068] Add 140mg of EDTA to a 50mL beaker, add 25mL of ultrapure water and stir rapidly for 5 minutes. Then add 0.8mL of Y(NO3)3 with a molar concentration of 0.6mol / L and 0.1mL of Yb2O3 with a molar concentration of 0.6mol / L and stir rapidly for 30min. Subsequently, add 2mL of NH4F with a molar concentration of 0.8mol / L and 2mL of CsF with a molar concentration of 0.8mol / L, and stir continuously for 30 minutes until a milky white solution is produced. After transferring the solution to a 200℃ autoclave, react for 24h, cool to room temperature, wash it alternately with ultrapure water and alcohol 3 times, and dry it at 70℃ for 2h to obtain CsYF4@Yb2O3 nanocomposite material. Dry for further use.

[0069] 1.2 Characterization of properties of CsYF4@Yb2O3 composite materials

[0070] The transmission electron microscopy and particle size distribution of CsYF4@Yb2O3 composite materials were determined as follows Figure 2 As shown in Figure 2, the photothermal temperature change is as follows: Figure 3 As shown, the CsYF4@Yb2O3 composite material has the strongest heating ability, which is better than CsYF4 and Yb2O3.

[0071] 1.3 CsYF4@Yb2O3 and antibody adsorption: Prepare a mixture of CsYF4@Yb2O3 composite material, estrone antibody, and bovine serum albumin, namely, a mixture of CsYF4@Yb2O3-mAb.

[0072] Take 1mL CsYF4@Yb2O3 in a centrifuge tube, add 4μL 0.2Wl / L K2CO3 solution to adjust the pH value of the system, shake and mix, then add 5μL 1mg / mL estrone antibody, mix and shake at room temperature for 45min. After the reaction, add 100μL BSA (m / m=5%) to block for 1h, centrifuge at 12000r / min for 30min, remove the supernatant, and redissolve in 100μL buffer (20mWl / L Na3PO4, 5% BSA, 0.25% Tween-20, 10% sucrose) to obtain CsYF4@Yb2O3-mAb mixed solution, which is stored at 4℃ for later use.

[0073] 1.4 Preparation of the test zone (T zone) solution

[0074] Estrone-BSA was diluted to 0.6 mg / mL in 10 mM PBS pH 7.4.

[0075] 1.5 Preparation of Quality Control Zone (Zone C) Solution

[0076] Dilute goat anti-mouse secondary antibody to 0.4 mg / mL in 10 mM PBS pH 7.4.

[0077] Example 2 Preparation of test strips

[0078] The NC membrane was pasted in the middle of the PVC bottom plate, and the sample pad and the absorbent pad were overlapped on the left and right ends of the NC membrane, so that they covered the NC membrane by about 2 mm. The assembled large card was cut into 3 mm wide strips, and the detection line (T zone) and the quality control line (C zone) were made on the NC membrane. The two lines were separated by 4 mm to obtain a blank test strip. 0.5 μL of T zone solution and 0.5 μL of C zone solution were added to the T zone and C zone respectively. The test strips after spotting were placed in an oven, dried at 37°C for 60 min, and stored in a vacuum bag for later use.

[0079] Example 3 Preparation of a Test Strip Containing a Binding Pad

[0080] Test strips according to Figure 1The binding mode consists of a sample pad, a nitrocellulose membrane (NC), a conjugate pad and a PVC base plate; the NC membrane is pasted in the middle of the PVC base plate, and a detection line (T zone) and a quality control line (C zone) are made on the NC membrane, with a spacing of 4 mm between the two lines; then the right end of the conjugate pad is overlapped on the left end of the NC membrane, so that it covers the NC membrane by about 2 mm, the sample pad is overlapped on the left end of the conjugate pad, so that it covers the conjugate pad by about 2 mm, and the absorbent pad is overlapped on the right end of the NC membrane, so that it covers the NC membrane by about 2 mm; the assembled large card is cut into 3 mm wide paper strips, and a mixture of 10 μL CsYF4@Yb2O3 composite material, estrone antibody, and bovine serum albumin, i.e., CsYF4@Yb2O3-mAb mixture, is fixed on the conjugate pad, and 0.5 μL T zone solution and 0.5 μL C zone solution are added to the T zone and C zone, respectively. The test strips after spotting are placed in an oven, dried at 37°C for 60 min, and stored in a vacuum bag for later use.

[0081] Example 4 Working curve drawing

[0082] Prepare 10 mL of 1 mg / mL estrone standard solution in acetonitrile and dilute to a concentration of 10 with 10 mM PBS. -2 pg / mL, 10 - 1 pg / mL, 10 0 pg / mL, 10 1 pg / mL, 10 2 pg / mL, 10 3 pg / mL, 10 4 pg / mL, 10 5 pg / mL, as the test solution. 80μL of the test solution was mixed with 10μL of CsYF4@Yb2O3-mAb and 10μL of running buffer (10mM PBS solution, containing 5% sucrose, 1% BSA, 1% Tween-20, pH 7.4) in a centrifuge tube for 10 minutes, and then the test strip was inserted into the centrifuge tube. After 10 minutes, the test strip was taken out and the test strip was dried with a near-infrared LED (power 1.36W / cm 2 ) for 3 minutes, and use a mobile phone and infrared thermal imaging accessories to monitor temperature changes. The results of the photothermal mode are as follows Figure 4 As shown; the working curve is y = 2.681x + 0.517 (R 2 =0.9891).

[0083] The results showed that in the photothermal mode, the negative T zone had the highest temperature and the estrone concentration was 10 5 pg / mL, the temperature of the T zone dropped to the lowest, and this concentration was the detection limit of the photothermal mode. Therefore, the detection limit of the constructed dual-mode test paper can reach 10 -1 pg / mL.

[0084] Example 5 Detection of estrone

[0085] The specificity verification of the CsYF4@Yb2O3 composite photothermal quantitative test strip for estrone includes the following steps:

[0086] 1. Preparation of test paper materials

[0087] Same as Example 1.

[0088] 2. Preparation of test strips

[0089] Same as Example 3.

[0090] 3. Working curve drawing

[0091] Same as Example 4.

[0092] 4. Specificity

[0093] Use acetonitrile to prepare 10 mL of 1 mg / mL standard solution of estrone, estradiol, estriol, diethylstilbestrol, and hexestrol, and dilute it with 10 mM PBS to a concentration of 120 ng / mL for later use as the test solution.

[0094] 5. Sample testing

[0095] 80 μL of the test solution was mixed with 10 μL of CsYF4@Yb2O3-mAb and 10 μL of running buffer (10 mM PBS solution, containing 5% sucrose, 1% BSA, 1% Tween-20, pH 7.4) in a centrifuge tube for 10 min. Then the test strip was inserted into the centrifuge tube. After the test strip was dried, a near-infrared LED (power 1.36 W / cm 2 ) for 3 minutes, and use a mobile phone and infrared thermal imaging accessories to monitor temperature changes. The results of the photothermal mode are as follows Figure 5 Compared with the blank, estradiol, estriol, diethylstilbestrol, and hexylestrol have very weak effects on the T zone temperature of the test paper, while estrone has a very significant effect on the T zone temperature of the test paper, indicating that the test paper has a weak response to the four, that is, the test paper has good specificity.

[0096] It can be seen from the above embodiments that the CsYF4@Yb2O3 composite material provided in the present application is used in the photothermal test strips for preparing the photothermal test strips. There is no need to change the conventional structure of the test strips. It can be used as a photothermal signal probe, and can be used independently of the photothermal test strips for convenient storage, or fixed on the binding pad of the test strips for use, which is convenient to carry. The detection method provided by the present invention includes photothermal test strips. The photothermal test strips for detecting estrone are based on the plasma resonance effect, and the CsYF4@Yb2O3 composite material with high photothermal conversion efficiency and tiny size is used as the T-zone fixed photothermal signal probe, near-infrared laser light source excitation, combined with smart terminals and infrared thermal imaging accessories to realize the collection of photothermal signals, effectively remove the base color of the sample liquid and the fluorescence background interference of the test strips, thereby improving the signal-to-noise ratio. The inspection method has a lower detection limit, a wider detection range and better specificity, and is more sensitive than other photothermal detection test strips.

[0097] The embodiments provided above are not intended to limit the scope of the present invention, and the steps described are not intended to limit the execution order thereof. Those skilled in the art may make obvious improvements to the present invention in combination with existing common knowledge, which also fall within the scope of protection defined by the claims of the present invention.

Claims

1. A test paper for detecting estrone, characterized in that, The test paper comprises a photothermal signal probe and a test strip body; The photothermal signal probe is prepared by modifying a CsYF4@Yb2O3 composite material with an estrone monoclonal or polyclonal antibody, and is used in a form independent of the main structure of the photothermal test strip or in a form dried on a conjugate pad; The test strip body comprises a PVC bottom plate, a sample pad, a nitrocellulose membrane (NC membrane), and an absorption pad.

2. The test paper for detecting estrone according to claim 1, characterized in that, The preparation method of the CsYF4@Yb2O3 composite material comprises the following steps: (1) Y(NO3)3 and Yb2O3 are mixed in an ethylenediaminetetraacetic acid aqueous solution, and NH4F solution and CsF solution are added in sequence under stirring, and stirring is continued until a milky white solution is produced; (2) The milky white solution is placed at high temperature for reaction, cooled to room temperature after the reaction is completed, washed and dried to obtain the CsYF4@Yb2O3 composite material.

3. The test paper for detecting estrone according to claim 2, characterized in that, In step (1), one or more of the following conditions are met: The molar ratio of Y(NO3)3 to Yb2O is 1:10-10:1; The concentration of the EDTA aqueous solution is 5-7 mg / mL; The concentration of NH4F solution is 0.8-1.2 mol / L; The concentration of CsF solution is 0.8-1.2 mol / L; Y(NO3)3 with NH4F and CsF 1:5-5:1; The stirring temperature is room temperature and the time is 5-30min; In step (2), one or more of the following conditions are met: The temperature of the high temperature reaction is 160-250°C and the time is 12-36h; Clean with ultrapure water and alcohol alternately 2-3 times; Drying is performed at 50-80°C for 1-4 hours.

4. A photothermal signal probe prepared from the CsYF4@Yb2O3 composite material of claim 1, characterized in that: Contains CsYF4@Yb2O3 composite material, estrone antibody and bovine serum albumin.

5. The photothermal signal probe according to claim 4, characterized in that: The CsYF4@Yb2O3 composite material is mixed with the test object antibody and bovine serum albumin to obtain a CsYF4@Yb2O3-mAb mixed solution.

6. A test strip containing the photothermal signal probe according to claim 4, characterized in that: The test strip includes a photothermal signal probe and a test strip body; The test strip body comprises: a sample pad, a nitrocellulose membrane, i.e., an NC membrane, and an absorption pad are overlapped and pasted in sequence from top to bottom in a horizontal direction on a PVC bottom plate; wherein the nitrocellulose membrane is used to separate and detect analytes from other substances in the sample, the sample pad is used for loading the sample, and the absorption pad is used to absorb excess liquid, and the PVC bottom plate provides physical support for the test strip; the nitrocellulose membrane comprises a detection area, i.e., a T area, and a quality control area, i.e., a C area; wherein, an estrogen antigen, i.e., a molecule-protein conjugate to be tested, is fixed on the T area; and a secondary antibody is fixed on the C area, and the secondary antibody is a secondary antibody directed against the source of the primary antibody, i.e., an anti-primary antibody; The photothermal signal probe is used in a form independent of the main structure of the photothermal test strip, or the photothermal signal probe is dried on a conjugate pad and the conjugate pad is inserted between the sample pad and the NC membrane for use.

7. The test strip according to claim 6, characterized in that: The source of the estrone antibody, ie, the primary antibody, includes at least one of mouse, rat, and rabbit.

8. The test strip according to claim 6, characterized in that: The secondary antibody comprises at least one of goat anti-mouse secondary antibody, rabbit anti-mouse secondary antibody, goat anti-rabbit secondary antibody and donkey anti-rabbit secondary antibody.

9. An application of the test strip according to claim 6, characterized in that: Used to detect estrone; the photothermal temperature of the detection area is negatively correlated with the estrone content to be detected, and the color intensity is negatively correlated with the estrone content in the sample, specifically: When the sample does not contain estrone, the T zone appears purple and has a high temperature; When the sample contains estrone, the T zone appears light purple or even disappears, and the temperature decreases; The quality control area is used as a reference to verify the validity of the test paper results and always appears purple.

10. The use according to claim 9, characterized in that: The method of testing estrone with a test strip comprises the following steps: When the photothermal signal probe is used in a form independent of the main structure of the photothermal test strip, it specifically includes: The sample to be tested and the CsYF4@Yb2O3-mAb solution are placed in a running buffer and mixed for 3-10 minutes, and then placed in the test strip; after 15-30 minutes, the colorimetric result is read and semi-quantitative analysis is performed; a colorimetric result photo is obtained, and grayscale analysis is performed using image processing software for quantitative analysis; When the photothermal signal probe is dried on the conjugate pad and the conjugate pad is inserted between the sample pad and the NC film of the test paper main structure for use, the method specifically includes: The sample to be tested is mixed with the running buffer solution, and placed in the test strip. After 20-40 minutes, the colorimetric result is read, and a colorimetric result photo is obtained for semi-quantitative analysis. Grayscale analysis is performed using image processing software for quantitative analysis. After the test strip is dried, it is placed under a near-infrared LED light source for excitation, and the temperature result is obtained using a thermal imaging or temperature measuring device and an intelligent display terminal. The thermal imaging or temperature measuring device includes at least one of a mobile phone infrared thermal imaging analysis accessory, an infrared thermal imager, and a temperature measuring gun. The intelligent display terminal includes at least one of a computer and a smart phone. The thermal imaging device collects photothermal imaging photos and outputs and displays them through the intelligent display terminal connected thereto.

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