Preparation method and application of a DNA detection probe carrier

Abstract

The present application discloses a vector for preparing a DNA detection probe, a construction method thereof and an application thereof. The vector is a Pt / Ti3C2T x nanoparticle, which is prepared by reducing and loading platinum nanoparticles using the two-dimensional material Ti3C2T x without the need to additionally add a reducing agent. The Pt / Ti3C2T x nanoparticle has a relatively dark initial color and has good peroxidase-like catalytic activity. Therefore, it can be introduced as a bifunctional signal tag into a lateral flow chromatography biosensor, and this signal tag adopts an aggregation signal amplification technique and a catalytic signal amplification technique to improve the sensitivity and accuracy of the lateral flow test strip biosensor. In addition, based on the Pt / Ti3C2T x nanoparticle as a signal carrier, a probe is prepared by labeling SH-DNA through Pt-S bonds, which can be applied to the detection of HIV-DNA, and can obtain detection results earlier, which is beneficial to the treatment of patients and the effective control of the virus.

Description

Technical Field

[0001] This application relates to the field of biological detection technologies, and particularly to carriers for preparing DNA detection probes, construction methods thereof, and applications thereof. More specifically, it relates to a carrier for preparing DNA detection probes, constructing a DNA detection probe or a test strip using the carrier, and the application of the probe or the test strip in HIV-DNA detection. Background Art

[0002] AIDS, that is, acquired immunodeficiency syndrome, is a disease caused by human immunodeficiency virus (HIV) infection, resulting in immune deficiency. It is one of the major diseases causing significant morbidity and mortality worldwide and remains a major public health problem. The effective management of HIV infection depends on the early and accurate detection of the disease. Currently, HIV diagnosis techniques are determined by detecting the virus's antibodies, antigens, and nucleic acids. Among them, HIV antibody or antigen detection can be used to determine the HIV infection status and is the most common method for diagnosing HIV infection at present. However, the window period for HIV antibody and antigen detection is long, which is not conducive to the control and management of the virus.

[0003] Compared with detecting HIV antibodies and antigens, HIV gene (HIV-DNA) can be detected earlier, so as to obtain the detection result earlier, which is beneficial to the treatment of patients and the effective control of the virus. Therefore, HIV virus nucleic acid detection has attracted more and more attention in the field of disease diagnosis, and more and more detection methods such as colorimetric detection, fluorescence detection, electrochemical detection, chemiluminescence detection, and surface-enhanced Raman spectroscopy (SERS) are used for nucleic acid detection. Although these methods can provide high sensitivity and accurate results, most of them require expensive instruments or complex detection processes or professional operators, which hinders their application in on-site and rapid detection.

[0004] The colorimetric lateral flow strip biosensor (CLFSB) is used to detect HIV-DNA and does not require the cooperation of other precision instruments and can be directly read by the naked eye. However, the CLFSB relies on the appearance / disappearance of color to identify the analyte, and its limited sensitivity still cannot meet the actual application requirements. For this reason, on the basis of the original technology, a signal amplification strategy is adopted to improve the sensitivity of the CLFSB (aggregation method signal amplification method). Nevertheless, most test strips are determined based on single-mode reading, that is, the color of the material itself is used as the color signal for reading determination. This mode is vulnerable to external interference (for example, due to different operators, non-standard detection processes, and different external environments), resulting in inaccurate results.

[0005] To more sensitively detect HIV-DNA, especially for rapid on-site detection, it still faces great challenges to develop a convenient, low-cost, and highly sensitive HIV-DNA biosensor. Summary of the Invention

[0006] In view of the problems in the prior art that the CLFSB for detecting HIV-DNA is vulnerable to external interference in the single-mode, in this application, the dual-mode CLFSB reading mode can make up for the deficiencies of the single mode. The dual mode is based on the original single mode (i.e., the material itself has a color as a color signal for detection), and a colored substance is generated by the material catalyzing the reaction substrate, further strengthening the color signal. When the color signal is used for detection, the detection sensitivity and linear range are improved.

[0007] Two-dimensional transition metal carbides or carbonitrides (MXene) are a general term for a new type of two-dimensional transition metal carbides and nitrides, with the general formula M n+1 X n T x (n = 1-3), where M is a pre-transition metal element, X is carbon or nitrogen element, and T refers to active functional groups such as fluorine-based, hydroxyl, or oxygen-based groups bonded to the surface of the material. MXene materials have an ultra-thin structure and excellent physical and chemical (electronic, optical, magnetic, etc.) properties. Their large surface area and strong absorption in the near-infrared region, combined with their ability to bind to various molecules or nanoparticles through surface modification, have gradually expanded the application of MXene in the biomedical field, such as being used to prepare a colorimetric lateral flow strip biosensor, improving its detection sensitivity and accuracy.

[0008] In this application, an MXene material, namely Ti3C2T x , is screened out, and with Ti3C2T x as a reducing agent and carrier, platinum nanoparticles are prepared by loading to form Pt / Ti3C2T x nanoparticles. Finally, Pt / Ti3C2T x nanoparticles are used as signal carriers to label DNA to prepare a probe. The original color of this probe is relatively dark, and it has good peroxidase-like activity, which can catalyze the chromogenic reaction triggered by 3-amino-9-ethylcarbazole (AEC) and hydrogen peroxide (H2O2), or catalyze the chromogenic reaction triggered by 3,3',5,5'-tetramethylbenzidine (TMB) and o-phenylenediamine (OPD), and is applied to the detection of HIV-DNA. During the detection process, dual-mode signals are used for reading.

[0009] Based on the above inventive concept, the embodiments of this application provide a carrier for preparing a DNA detection probe, a construction method, and its application to solve or alleviate some of the aforementioned technical problems.

[0010] First aspect, an embodiment of the present application provides a transition metal carbide support, namely Pt / Ti3C2T x nanoparticles, which are applied to the preparation of DNA detection probes. The transition metal carbide support includes:

[0011] a support; the support is a nanosheet made of two-dimensional material Ti3C2T x ; and

[0012] platinum nanoparticles loaded on the support.

[0013] Further, in the Ti3C2T x , T represents any one of active functional groups such as fluoro group, hydroxyl group or oxy group, and the T is bonded to the surface of the Ti3C2 material to form Ti3C2T x ; X is any natural number greater than or equal to 1.

[0014] Further, the hydrated particle size of the nanosheet is 50-400 nm.

[0015] Further, the nanosheet is prepared by etching Ti3AlC2 with lithium fluoride and hydrochloric acid solution.

[0016] Second aspect, an embodiment of the present application provides a probe for detecting HIV-DNA, which includes:

[0017] the transition metal carbide support described in the first aspect, namely Pt / Ti3C2T x nanoparticles; and

[0018] labeled DNA, the labeled DNA is labeled on the Pt / Ti3C2T x nanoparticles, and the labeled DNA is used to form a hybrid with HIV-DNA by complementary hybridization.

[0019] Third aspect, the present application provides a preparation method of the probe described in the second aspect, which includes:

[0020] preparing Ti3C2T x nanosheets;

[0021] loading platinum nanoparticles on the Ti3C2T x nanosheets to obtain the transition metal carbide support described in the first aspect, namely Pt / Ti3C2T x nanoparticles; and

[0022] coupling the labeled DNA with the Pt / Ti3C2T x nanoparticles to obtain the probe.

[0023] Further, the Pt / Ti3C2T xThe nanoparticles have peroxidase-like activity and can catalyze a substrate composition, which is any one of the following combinations:

[0024] (1) A combination of 3-amino-9-ethylcarbazole and hydrogen peroxide;

[0025] (2) A combination of 3,3',5,5'-tetramethylbenzidine and hydrogen peroxide;

[0026] (3) A combination of o-phenylenediamine and hydrogen peroxide.

[0027] In a fourth aspect, the present application provides a test strip for detecting HIV-DNA, which comprises the probe described in the second aspect.

[0028] Further, the test strip includes a base plate, a sample pad, an absorption pad, and a nitrocellulose membrane (NC membrane); wherein,

[0029] The nitrocellulose membrane is on the base plate, one end of the nitrocellulose membrane is covered with an absorption pad, and the other end is covered with a sample pad. A test line (T line) and a control line (C line) are provided on the non-covered surface of the nitrocellulose membrane.

[0030] Further, the test strip further includes a conjugate pad, one end of which is located below the absorption pad and the other end is located above the cellulose membrane. The conjugate pad is sprayed with a conjugate of the probe described in the second aspect and streptavidin.

[0031] In a fifth aspect, the present application provides the use of the transition metal carbide support described in the first aspect, the probe described in the second aspect, or the test strip described in the fourth aspect in the detection of HIV-DNA.

[0032] In a sixth aspect, the present application provides a method for detecting HIV-DNA, which includes:

[0033] Preparing an HIV-DNA standard solution;

[0034] Dropping the above standard solution onto the sample pad of the test strip described in the fourth aspect and rinsing with sodium citrate buffer (SSC); and

[0035] Dropping the substrate composition onto the T line and the C line respectively and developing color to obtain a test result.

[0036] Further, the substrate composition is any one of the following combinations:

[0037] (1) A combination of 3-amino-9-ethylcarbazole and hydrogen peroxide;

[0038] (2) A combination of 3,3',5,5'-tetramethylbenzidine and hydrogen peroxide;

[0039] (3) A combination of o-phenylenediamine and hydrogen peroxide.

[0040] Further, the addition of the HIV-DNA standard solution can be carried out in another way:

[0041] Mix the probe described in the second aspect with the HIV-DNA standard solution and incubate, then add the mixture dropwise onto the sample pad of the test strip. Among them, the test strip does not contain the probe described in the second aspect, and other components and structures are the same as those of the test strip described in the fourth aspect.

[0042] In the seventh aspect, the present application provides the application of the transition metal carbide carrier described in the first aspect in the preparation of a lateral flow chromatography biosensor.

[0043] Compared with the prior art, the present application has at least the following beneficial effects:

[0044] The present application relates to a carrier, a construction method and an application thereof for preparing a DNA detection probe. The carrier, namely Pt / Ti3C2T x nanoparticles are prepared by reducing and loading platinum nanoparticles using the two-dimensional material Ti3C2T x , and no additional reducing agent is required in this process. The prepared Pt / Ti3C2T x nanoparticles have a relatively dark initial color and good peroxidase-like activity. Therefore, they can be introduced as a bifunctional signal label into a lateral flow chromatography biosensor. This signal label adopts an aggregation signal amplification technology and a catalytic signal amplification technology to improve the sensitivity and accuracy of the lateral flow test strip biosensor. In addition, based on Pt / Ti3C2T x nanoparticles as a signal carrier, SH-DNA is labeled with a Pt-S bond to prepare a probe, which can be applied to the detection of HIV-DNA, and the detection result can be obtained earlier, which is beneficial to the treatment of patients and the effective control of the virus. Description of the Drawings

[0045] Figure 1 This is a transmission electron microscope scanning image of the Pt / Ti3C2T x nanoparticles provided by the embodiment of the present application; among them, A is the thin-layer flaky structure of the Ti3C2T x nanoparticles, and B is the large sheet structure of the Pt / Ti3C2T x nanoparticles being damaged into small single-piece structures.

[0046] Figure 2 This is an energy spectrum diagram of the scanning electron microscope of the Pt / Ti3C2T x nanoparticles provided by the embodiment of the present application; among them, A is the scanning electron microscope image of the nanoparticles, and B, C, and D are the distribution diagrams of C, Pt, and Ti elements respectively.

[0047] Figure 3 This is a Zeta potential diagram provided by the embodiment of the present application.

[0048] Figure 4 This is the schematic diagram of the probe for detecting HIV-DNA provided by the embodiments of the present application.

[0049] Figure 5 This is the detection result graph of the target analytes with different concentrations provided by the embodiments of the present application; among them, A is the result of the color signal of the material itself, and B is the result with the enhancement effect of the chromogenic substrate. Detailed implementation manners

[0050] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0051] Pt / Ti3C2T x Nanoparticles and preparation method

[0052] The embodiments of the present application disclose a transition metal carbide support, which is applied to the preparation of DNA detection probes. The transition metal carbide support includes a support and platinum nanoparticles loaded on the support. The support is a nanosheet made of two-dimensional material Ti3C2T x material. Ti3C2T x is a general term for a new type of two-dimensional transition metal carbides and nitrides, and the general formula is M n+1 X n T x (n = 1 to 3), where M is a pre-transition metal element, X is a carbon or nitrogen element, and T refers to active functional groups such as fluorine groups, hydroxyl groups or oxygen groups bonded to the surface of the material. T represents any one of active functional groups such as fluorine groups, hydroxyl groups or oxygen groups, and the T is bonded to the surface of the Ti3C2 material to form Ti3C2T x ; the X is any natural number greater than or equal to 1. The "bonding" means that the surface of the Ti3C2 material and the T are combined into one body through van der Waals forces, molecular forces or even atomic forces.

[0053] In some embodiments of the present application, the hydrodynamic particle size of the nanosheet is 50 to 400 nm.

[0054] In some embodiments, the nanosheet is prepared by etching Ti3AlC2 with lithium fluoride and hydrochloric acid solution.

[0055] In some embodiments, the Pt / Ti3C2T x nanoparticles can be used to prepare probes for detecting DNA, test strips with the probes as substrates, or colorimetric lateral flow strip biosensors (CLFSB), such as probes, test strips or CLFSB instruments for detecting HIV-DNA.

[0056] In some embodiments, the preparation method of the Pt / Ti3C2T x nanoparticles comprises:

[0057] Preparing Ti3C2T x nanosheets: At 35 °C, etching Ti3AlC2 with lithium fluoride and concentrated hydrochloric acid for 24 hours. After the reaction is completed, wash with water multiple times until the pH value is about 6, and prepare Ti3C2T x nanosheets by ultrasonic treatment.

[0058] Preparing Pt / Ti3C2T x nanoparticles: Using Ti3C2T x nanosheets as a reducing agent and a carrier, adding chloroplatinic acid to the solution and stirring at room temperature for 10 min. Then heat the solution from room temperature to 92 °C and keep it for 1 min to synthesize Pt / Ti3C2T x nanoparticles. The Pt / Ti3C2T x nanozyme has good peroxidase-like activity.

[0059] Results: The characterization results of the Ti3C2T x @Pt nanozyme particles are as follows:

[0060] A. From transmission electron microscopy and scanning electron microscopy: It can be seen from the TEM image ( Figure 1 A) that the synthesized two-dimensional material Ti3C2T x is a thin-layer flaky structure. It can be seen from the TEM image ( Figure 1 B) that the large sheet structure of the two-dimensional material Ti3C2T x is damaged, and small single sheets with a size of about 100 nm are generated, and platinum nanoparticles are in-situ grown on the surface. The measured hydrodynamic diameter is 107 nm. From the SEM / EDS image ( Figure 2 ) it shows that the Ti, C, and Pt elements in the material are evenly distributed.

[0061] B. Zeta potential: As Figure 3 shown, the zeta potentials of Ti3C2T x , Pt / Ti3C2T x , Pt / Ti3C2T x -DNA are -28.9, -1.46, and -34.8 respectively, indicating that the platinum nanoparticles are successfully loaded on the two-dimensional material Ti3C2T x and demonstrating that the labeled DNA (SH-DNA) is successfully labeled on the surface of the Pt / Ti3C2T x nanoparticles.

[0062] Probe for Detecting HIV-DNA and Preparation Method

[0063] In some embodiments, the probe for detecting HIV-DNA comprises:

[0064] Transition metal carbide support, namely the aforementioned Pt / Ti3C2T x nanoparticles, which are prepared by the aforementioned preparation method; and

[0065] Labeled DNA; the labeled DNA (SH-DNA) is labeled on the signal carrier; the SH-DNA is used to form a hybrid by complementary hybridization with the HIV-DNA to be detected.

[0066] In some embodiments, the probe comprises Pt / Ti3C2T x nanoparticles, and the Pt / Ti3C2T x nanoparticles have peroxidase-like activity and can catalyze the reaction of the substrate composition to generate a colored product. In some embodiments, the substrate composition is 3-amino-9-ethylcarbazole (AEC) and hydrogen peroxide (H2O2) for color development reaction. In some embodiments, the substrate composition is 3,3',5,5'-tetramethylbenzidine (TMB) and o-phenylenediamine (OPD). Utilizing this property, the probe can be used for the detection of HIV-DNA.

[0067] In some embodiments, the process for preparing the probe is as Figure 4 shown, including the two-dimensional material Ti3C2T x loaded with platinum nanoparticles as the signal carrier, and then connecting SH-DNA to obtain. In some embodiments, the method for preparing the probe for detecting HIV-DNA comprises:

[0068] Mix equal volumes of 100 μM SH-DNA and 10 mM tris(2-carboxyethyl)phosphine hydrochloride (TCEP) evenly and incubate for more than 30 min;

[0069] Add the Pt / Ti3C2T x nanoparticles prepared by the aforementioned method, incubate in a shaker for 1 h, and then leave it in the refrigerator overnight;

[0070] Wash with phosphate buffered saline (PBS) containing bovine serum albumin (BSA), and finally disperse it in the prepared dispersion solution and store it in a 4°C refrigerator.

[0071] Test Strip for Detecting HIV-DNA and Preparation Method

[0072] In some embodiments, Figure 4The structure diagram of the test strip for detecting HIV-DNA is shown in the figure. It can be seen from the figure that the main body of the test strip is composed of a base plate, a sample pad, an absorption pad and a nitrocellulose membrane (NC membrane); wherein the nitrocellulose membrane is on the base plate, one end of the nitrocellulose membrane is covered with an absorption pad, and the other end is covered with a sample pad, and a detection line (T line) and a control line (C line) are arranged on the non-covered surface of the nitrocellulose membrane, and the sample pad needs to be sealed with a sealing liquid before assembling the test strip, and then dried for use.

[0073] In some embodiments, the probe for detecting HIV-DNA in the sample is sprayed on the sample pad or one end of the nitrocellulose membrane close to the sample pad, and the probe is complementary to the nucleotide sequence of the HIV-DNA to be detected; the capture probe (T-DNA) and streptavidin conjugate are sprayed on the T line, and the T-DNA is complementary to the nucleotide sequence of the aforementioned probe; the quality control probe (C-DNA) and streptavidin conjugate are sprayed on the C line, and the C-DNA is complementary to the nucleotide sequence of the sample to be detected. In some embodiments, the nanomaterial on the probe has a peroxidase-like activity that catalyzes the reaction of the substrate composition to generate a color product. After the reaction is completed, the corresponding substrate composition, such as AEC and H2O2, or TMB and H2O2, or OPD and H2O2, is sprayed on the corresponding T line and C line.

[0074] In certain embodiments, the test strip further comprises a conjugate pad, one end of which is located below the absorbent pad and the other end of which is located above the cellulose membrane, the conjugate pad being sprayed with a detection probe for detecting HIV-DNA and a conjugate of streptavidin, the detection probe being complementary to the nucleotide sequence of the HIV-DNA to be detected.

[0075] In certain embodiments, the method for preparing the test strip for detecting HIV-DNA comprises:

[0076] 1. Preparation of nitrocellulose membrane

[0077] 12μL 2mg / mL streptavidin and 60μL 30μM T-DNA were mixed and incubated for 1 hour to form a streptavidin-biotinylated DNA complex. After the reaction, the test line (T line) was obtained by coating the nitrocellulose membrane at a streaking rate of 2μL / cm; the C-DNA was treated in the same way to obtain the control line (C line).

[0078] 2. Preparation of sample pad

[0079] Cut the glass fiber membrane into a specification with a width of 30 cm and a length of 23 mm, soak it in a buffer solution (pH = 8.0, 0.15 M NaCl, 0.25% Triton X-100 and 0.02 M Tris-HCl) for 15 min, then air-dry it in natural air and store it in a constant temperature and humidity chamber for later use.

[0080] 3. Preparation of the absorption pad

[0081] Cut the blotting paper into a specification with a length of 30 cm and a width of 17 mm to obtain the absorption pad.

[0082] 4. Assembly of the test strip

[0083] First, attach the nitrocellulose membrane to the middle of the bottom plate, then press the sample pad 1 - 3 mm on the nitrocellulose membrane, and press the absorption pad 1 - 3 mm on the nitrocellulose membrane and attach them to the bottom plate in sequence. After compaction, finally cut it into a strip with a width of 3.8 mm and a length of 8 cm to obtain the test strip for rapid detection of HIV-DNA.

[0084] Test Strip for Detecting HIV-DNA

[0085] Use the test strip prepared in this application to detect HIV-DNA, and the detection process is as follows:

[0086] Dissolve the HIV-DNA standard in 10 mM PBS buffer and dilute it to multiple different concentrations between 0 and 50 nM (0, 0.1, 0.5, 0.8, 1, 2, 5, 8, 30, 50 nM respectively), and use 10 mM PBS as the blank control group;

[0087] Mix 180 μL of the probe with 20 μL of the HIV-DNA standard solution and incubate for 5 min (in some embodiments, a test strip containing a conjugate pad can also be used, and the sample to be tested can be directly dropped onto the sample pad for reaction, thus reducing this step of operation);

[0088] Then drop the above detection solution onto the sample pad of the test strip in two portions, 30 μL each time; finally, rinse it twice with the SSC rinse solution, and use a mobile phone camera to take pictures of the test results. The detection method is carried out through single mode and dual mode.

[0089] Single mode: Analyze the gray value of the T line with imageJ software.

[0090] Dual mode (signal enhancement mode): Drop 1 μL of AEC-H2O2 reaction solution on the T line and the C line respectively, take pictures of the test results with a mobile phone after 3 min, and analyze the gray value of the T line with imageJ software.

[0091] Result: As Figure 5As shown, where A shows the test result of the test strip without spraying the substrate composition containing AEC and H2O2 on the T line and C line for the HIV-DNA solution, and B shows the test result of the test strip with the substrate composition containing AEC and H2O2 sprayed on the T line and C line for the HIV-DNA solution. Without adding AEC and H2O2, the linear detection range of the target is 0.8 nM - 50 nM; after adding the substrate AEC and H2O2, the linear detection range of the target is broadened to 0.1 nM - 50 nM. Therefore, using the test strip with enhanced color development effect can detect HIV-DNA with higher sensitivity.

[0092] In summary, the present application provides a transition metal carbide support, namely Pt / Ti3C2T x nanoparticles. The Pt / Ti3C2T x nanoparticles are synthesized by using Ti3C2T x as a natural reducing agent and support, and adopting a self-reduction method to synthesize Pt nanoparticles with peroxidase-like activity modified on Ti3C2T x nanosheets. No external reducing agent is added in this process. Among them, the conversion rate of platinum ions into platinum nanoparticles is as high as 61%. The original color of the Pt / Ti3C2T x nanoparticles is relatively dark, and it has good peroxidase-like activity. Therefore, it is introduced as a bifunctional signal label into the lateral flow chromatography biosensor. This signal label adopts the aggregation signal amplification technology and the catalytic signal amplification technology to improve the sensitivity and accuracy of the lateral flow test strip biosensor. By using the Pt / Ti3C2T x nanoparticles as a signal carrier to adsorb and label DNA, a probe can be prepared. The probe can be used to prepare a test strip for detecting HIV-DNA, and the test result can be obtained earlier, which is beneficial to the treatment of patients and the effective control of the virus.

[0093] The above is only the preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed in the present application should be covered by the protection scope of the present application.

Claims

1. Use of a probe in the preparation of a colorimetric lateral flow test strip for detecting HIV-DNA, wherein the preparation method of the probe comprises: Etch Ti3AlC2 with lithium fluoride and concentrated hydrochloric acid for 24 hours at 35 °C. After the reaction is completed, wash with water until the pH value reaches 6, and prepare Ti3C2Tx nanosheets by ultrasonic treatment, where T represents any one of fluoro, hydroxy or oxo active functional groups, and the T is bonded to the surface of the Ti3C2 material to form Ti3C2Tx. x The X is any natural number greater than or equal to 1, and the hydrodynamic diameter of the nanosheets is 50-400 nm. x ​ Using the Ti3C2T x nanosheets as a reducing agent and carrier, add chloroplatinic acid to the solution and stir at room temperature for 10 min. Then heat the solution from room temperature to 92 °C and keep it for 1 min to synthesize Pt / Ti3C2T x nanoparticles; Mix equal volumes of 100 μM SH-DNA and 10 mM tris(2-carboxyethyl)phosphine hydrochloride evenly and incubate for more than 30 min; Add the Pt / Ti3C2T x nanoparticles, incubate on a shaker for 1 h, and then leave it in the refrigerator overnight; Wash with phosphate buffered saline containing bovine serum albumin and disperse in the prepared dispersion.

2. According to the use described in claim 1, the test strip body is composed of a base plate, a sample pad, an absorption pad, and a nitrocellulose membrane; wherein, A nitrocellulose membrane is placed on a bottom plate. One end of the nitrocellulose membrane is covered with an absorbent pad, and the other end is covered with a sample pad. A test line and a control line are provided on the non-covered surface of the nitrocellulose membrane; The probe is sprayed on the sample pad or at one end of the nitrocellulose membrane close to the sample pad. The probe is complementary base-paired with the nucleotide sequence of the HIV-DNA to be detected. A conjugate of a capture probe and streptavidin is sprayed on the T line, and T-DNA is complementary base-paired with the nucleotide sequence of the sample to be detected; A conjugate of a control probe and streptavidin is on the C line, and C-DNA is complementary base-paired with the nucleotide sequence of the probe.

3. The use according to claim 2, wherein the steps of detecting HIV-DNA comprise: Prepare an HIV-DNA standard solution; Drop the standard solution onto the sample pad of the test strip and rinse with sodium citrate buffer; And Drop a substrate composition onto the test line and the control line respectively, and develop color to obtain a test result; The substrate composition is any one of the following combinations: (1) a combination of 3-amino-9-ethylcarbazole and hydrogen peroxide; (2) a combination of 3,3',5,5'-tetramethylbenzidine and hydrogen peroxide; (3) a combination of o-phenylenediamine and hydrogen peroxide.

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