A membrane scratching buffer, its preparation method, and an immunochromatographic reagent strip

Abstract

This invention discloses a membrane-spreading buffer and its preparation method, as well as an immunochromatographic reagent strip, relating to the field of immunochromatographic detection technology. This invention improves the signal intensity of the immunochromatographic reagent strip by adding a dissociation salt, including sodium azide at a concentration of 0.1% to 2% and / or potassium thiocyanate at a concentration of 0.01% to 2%, to enhance the detection sensitivity. In addition, the method is simple to operate, cost-controllable, and is in the process of being promoted.

Description

Technical Field

[0001] This invention relates to the field of immunochromatographic detection technology, and more specifically, to a membrane scratching buffer, its preparation method, and immunochromatographic reagent strips. Background Technology

[0002] Fluorescent immunochromatography (FIC) offers advantages such as low cost, simple operation, speed, and portability, making it an important part of the in vitro diagnostics field. FIC is a novel membrane detection technology based on antigen-antibody specific immune reactions. This technique uses a strip-shaped chromatographic material immobilized with a detection line (coated with antibody or antigen) and a control line (anti-antibody) as the stationary phase, and the test solution as the mobile phase. Fluorescent microspheres labeled with antibodies or antigens are immobilized on connecting pads, and the analyte moves along the chromatographic strip through capillary action. It is mainly used for the specific qualitative and quantitative detection of various proteins, antibodies, and small molecule compounds, including those related to infectious diseases, microorganisms, pregnancy, ovulation, myocardial infarction, drugs, and other conditions.

[0003] For low-value detection in fluorescence chromatography, due to the small amount of analyte, the insufficient binding of the capture and the analyte results in the inability to detect and distinguish low-content analytes. Existing technologies for improving the detection sensitivity of immunochromatographic reagent strips mainly include the following categories: (1) improving detection sensitivity by optimizing the signal acquisition, signal enhancement, and data processing of the immunochromatographic reagent strip reader, such as patent CN103018439A; (2) improving detection sensitivity by introducing a cascade amplification system such as the biotin-streptavidin system or a multi-enzyme cascade amplification system, such as patent CN110596404A; (3) increasing the binding probability of antigen and antibody through membrane modification, thereby improving the detection sensitivity and signal intensity in the low-value region, such as patent CN108535472A.

[0004] While these methods improve the detection sensitivity of immunochromatographic reagent strips to some extent, their ability to improve detection sensitivity is limited. In addition, these methods require the introduction of new systems or the upgrading of signal reading instruments and signal processing software, which are relatively cumbersome to operate and relatively expensive.

[0005] In view of this, the present invention is proposed. Summary of the Invention

[0006] The purpose of this invention is to provide a membrane-spreading buffer, its preparation method, and an immunochromatographic reagent strip.

[0007] This invention is implemented as follows:

[0008] In a first aspect, embodiments of the present invention provide a membrane-spreading buffer, comprising at least one of a first ionizing salt and a second ionizing salt, and a membrane-spreading buffer matrix, wherein the first ionizing salt is NaN3, and the cation of the second ionizing salt is SCN. - In the membrane-spreading buffer, the mass fraction of the first dissociation salt is 0.1% to 2%, and the mass fraction of the second dissociation salt is 0.01% to 2%.

[0009] Secondly, embodiments of the present invention provide a method for preparing a membrane-spreading buffer as described in the foregoing embodiments, which includes mixing the components of the membrane-spreading buffer.

[0010] Thirdly, embodiments of the present invention provide the application of NaN3 in the preparation of a membrane-spreading buffer for immunochromatographic detection.

[0011] Fourthly, embodiments of the present invention provide the use of NaN3 and / or the membrane-spreading buffer as described in the foregoing embodiments in the preparation of kits for improving the sensitivity of immunochromatographic detection.

[0012] Fifthly, embodiments of the present invention provide a method for preparing an immunochromatographic reagent sheet, which includes applying a membrane to a detection line antibody using the membrane-stretching buffer as described in the foregoing embodiments to obtain a chromatographic membrane coated with the detection line.

[0013] Sixthly, embodiments of the present invention provide an immunochromatographic reagent tablet, which is prepared by the method for preparing immunochromatographic reagent tablets described in the foregoing embodiments.

[0014] The present invention has the following beneficial effects:

[0015] This invention improves the signal intensity of immunochromatographic reagent strips by adding a dissociation salt to the membrane-spreading buffer. The dissociation salt specifically includes sodium azide (NaN3) and / or potassium thiocyanate (KSCN), thereby effectively enhancing the detection sensitivity of the immunochromatographic reagent. This method is simple to operate, cost-controllable, and has been promoted for widespread application. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0017] This invention provides a membrane-spreading buffer, comprising at least one of a first ionizing salt and a second ionizing salt, and a membrane-spreading buffer matrix, wherein the first ionizing salt is NaN3, and the cation of the second ionizing salt is SCN. -In the membrane-spreading buffer, the mass fraction of the first dissociation salt is 0.1% to 2%, and the mass fraction of the second dissociation salt is 0.01% to 2%.

[0018] A dissociative salt is a salt that can disrupt the hydrogen bonds between water molecules, increasing their disorder. Examples of dissociative salts include perchlorates and isothiocyanates, commonly used in ion-pair chromatography. The addition of a suitable dissociative salt can enhance the hydrophobicity of ionic analytes and improve their adhesion to hydrophobic surfaces. This invention involves adding NaN3 and / or SCN to the membrane etching buffer. - This significantly improves the signal intensity of immunoassay reagent strips prepared using this membrane-spreading solution for chromatographic membrane detection lines and control lines, thereby enhancing the detection sensitivity.

[0019] In some embodiments, when the membrane-spreading buffer includes a first dissociative salt, the effective concentration of the first dissociative salt (NaN3) in the membrane-spreading buffer is 0.2% to 1%, specifically, it can be any one or any two of 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, 0.55%, 0.6%, 0.65%, 0.7%, 0.75%, 0.8%, 0.85%, 0.9%, 0.95%, and 1%, more preferably 0.5% to 1%, even more preferably 0.5% to 1%. Within the preferred range, the detection sensitivity can be further improved.

[0020] In some embodiments, when the membrane-spreading buffer includes a second dissociative salt, the mass fraction of the second dissociative salt in the membrane-spreading buffer is 0.01% to 1%, specifically, it can be any one or any two of 0.01%, 0.05%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, 0.55%, 0.6%, 0.65%, 0.7%, 0.75%, 0.8%, 0.85%, 0.9%, 0.95%, and 1%, more preferably 0.5% to 1%, and most preferably 0.5% to 1%. Within this preferred range, the detection sensitivity can be further improved.

[0021] Unless otherwise specified, the cation in the second liquid salt is a metal ion, specifically including at least one of Na, K, Fe and NH4, preferably at least one of Na and K, that is, the second liquid salt is at least one of KSCN and NaSCN.

[0022] In some embodiments, when the membrane-spreading buffer comprises a first ionizing salt and a second ionizing salt, the mixing mass ratio of the first ionizing salt and the second ionizing salt is (1-3):(1-3), specifically any one or any two of 1:1, 1:2, 1:3, 2:1, and 3:1, preferably 2:1. The preferred embodiment has better technical performance.

[0023] In the absence of any restrictions, the substrate of the coating buffer can be selected from existing conventional coating buffers (coating buffers without added NaN3 and KSCN).

[0024] Preferably, the membrane-spreading buffer matrix comprises a buffer solution and an additive, wherein the additive is selected from at least one of sucrose and EDTA.

[0025] Preferably, in the membrane-spreading buffer, the mass fraction of sucrose is 0.5% to 5%, specifically within any one or any two ranges of 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, and 5%. The effective concentration of EDTA is 0.1 to 5 mM, specifically within any one or any two ranges of 0.1 mM, 1 mM, 2 mM, 3 mM, 4 mM, and 5 mM.

[0026] Preferably, the buffer solution is selected from any one of PBS, PB, CB, CBS, MES, and HEPES.

[0027] Preferably, the pH of the buffer solution is 6.5 to 7.5, specifically any one or any two of 6.5, 6.7, 6.9, 7.1, 7.3, and 7.5, and more preferably 7.3.

[0028] This invention also provides a method for preparing the membrane-spreading buffer as described in any of the foregoing embodiments, which includes mixing the components of the membrane-spreading buffer, specifically by adding a ionizing salt to the membrane-spreading buffer matrix such that the ionizing salt meets the above-defined mass fraction (active concentration).

[0029] This invention also provides the application of NaN3 in the preparation of a membrane-spreading buffer for immunochromatographic detection.

[0030] Preferably, the mass fraction of NaN3 in the membrane-spreading buffer is 0.1% to 2%. It is understood that NaN3 corresponds to the first dissociation salt described in any of the foregoing embodiments, and its mass fraction in the membrane-spreading buffer can be the same as described in any of the foregoing embodiments. The specific preparation process of the membrane-spreading buffer is also the same as described in any of the foregoing embodiments, and will not be repeated here.

[0031] This invention provides the application of NaN3 and / or the membrane-spreading buffer as described in any of the foregoing embodiments in the preparation of kits for improving the sensitivity of immunochromatographic detection.

[0032] The membrane-spreading buffer prepared with NaN3 can be used to coat the detection lines of chromatographic membranes, and the resulting product has an effective improvement in detection sensitivity. Therefore, NaN3 and / or the membrane-spreading buffer described in any of the foregoing embodiments can be used as components of a kit to improve the sensitivity of immunochromatographic detection.

[0033] In some embodiments, the kit may also include other reagents for improving detection sensitivity.

[0034] This invention provides a method for preparing an immunochromatographic reagent strip, which includes applying a membrane to a detection line antibody using the membrane-spreading buffer solution as described in any of the foregoing embodiments, to obtain a chromatographic membrane coated with the detection line.

[0035] In some embodiments, the preparation method further includes applying the control line antibody to a membrane using the membrane application buffer as described in any of the foregoing embodiments to obtain a chromatography membrane coated with both the control line and the detection line. During membrane application, the detection line antibody and / or the control line antibody are mixed with the membrane application buffer, and the membrane is applied using a membrane application apparatus. As long as the detection line uses the membrane application buffer provided in this application, a significant improvement in detection sensitivity can be achieved.

[0036] In some embodiments, the preparation method further includes: sequentially attaching a sample pad, a conjugation pad, the chromatography membrane, and an absorbent pad to a substrate. Except for the components of the etching buffer, other preparation processes for the immunochromatographic reagent strip can be carried out using existing procedures. With other processes remaining the same, the etching buffer provided in this embodiment of the invention offers better detection sensitivity compared to existing etching buffers.

[0037] In addition, this invention also provides an immunochromatographic reagent tablet, which is prepared by the method for preparing immunochromatographic reagent tablets described in any of the foregoing embodiments.

[0038] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0039] Example 1

[0040] An immunochromatographic reagent strip is provided, and its preparation method includes the following steps.

[0041] (1) Preparation of membrane-spreading buffer

[0042] The membrane scratching buffer consists of a membrane scratching buffer matrix and a dissociation salt (NaN3). The membrane scratching buffer matrix includes sucrose, EDTA, and a buffer solution. The membrane scratching buffer is prepared by the following method: a buffer solution is prepared using pure water as the base solution; the prescribed amounts of sucrose, disodium tetraethylamine oxalate (EDTA), and dissociation salts of different concentrations are weighed and dissolved in the prescribed amount of base solution, mixed well, and the pH is adjusted to 7.3; the membrane scratching buffer is obtained by filtration sterilization using a filter membrane with a pore size of 0.22 μm.

[0043] Please refer to Table 1 for details.

[0044] Table 1. Formulation of membrane crossing buffer

[0045] Element content sucrose 2.5% (mass fraction) EDTA 1mM <![CDATA[NaN3]]> 0.5％ KSCN 0％ buffer solution 0.01M PBS pH 7.3

[0046] (2) Preparation of chromatography membrane

[0047] Antibody was applied to GE's nitrocellulose membrane using the above-mentioned coating buffer. In other embodiments, the nitrocellulose membrane could be from manufacturers including Merck, Pall, and Sartorius. After coating, the membrane was dried in a 37°C oven to obtain a chromatographic membrane with coated detection and control lines.

[0048] (3) Preparation of the binding pad

[0049] Labeled antibodies are coupled to fluorescent microspheres by chemical cross-linking and other methods to obtain fluorescent particles modified with labeled antibodies. The fluorescent particles modified with labeled antibodies are then spread on glass fibers to obtain fluorescent particle binding pads.

[0050] (4) Preparation of immunochromatographic reagent strips

[0051] The prepared chromatography membrane, fluorescent particle binding pad, sample pad, and absorption pad are attached to a polyvinyl chloride base plate in a certain order, cut into reagent strips, and assembled with corresponding plastic parts to form a complete reagent sheet, thus obtaining an immunochromatographic detection reagent sheet.

[0052] Example 2

[0053] An immunochromatographic reagent strip is provided, which is largely the same as that in Example 1, except that the dissociation salt is different. The dissociation salt is KSCN, and its effective concentration in the staining buffer is 0.1%.

[0054] Example 3

[0055] An immunochromatographic reagent strip is provided, which is largely the same as that in Example 1, except that the dissociation salt is different. The dissociation salt is a combination of NaN3 and KSCN in a mass ratio of 2:1, and the effective concentrations in the membrane scratching buffer are 0.04% and 0.02%.

[0056] Example 4

[0057] An immunochromatographic reagent strip is provided, which is largely the same as that in Example 1, except that the dissociation salt is different. The dissociation salt is NH4SCN, and its effective concentration in the staining buffer is 0.1%.

[0058] Experimental Example 1

[0059] The effect of different NaN3 concentrations on the CK-MB project.

[0060] (1) Preparation of membrane-spreading buffer

[0061] Based on the preparation of the membrane-spreading buffer provided in Example 1, multiple control groups were set up according to different concentrations of NaN3 and different buffers. The NaN3 concentrations in the PBS membrane-spreading buffer were 0%, 0.02%, 0.05%, 0.1%, 0.5%, and 1%, respectively, and the NaN3 concentrations in the PB membrane-spreading buffer were 0%, 0.02%, and 0.1%, respectively.

[0062] (2) Preparation of chromatography membrane

[0063] The above nine etching buffers were used to etch Pall nitrocellulose membranes. After etching, the membranes were dried in a 37°C oven to obtain chromatographic membranes coated with CK-MB antibody (detection line) and control line.

[0064] (3) Preparation of the binding pad

[0065] The CK-MB labeled antibody was coupled to fluorescent microspheres using chemical cross-linking and other methods to obtain CK-MB labeled antibody modified fluorescent particles. The CK-MB labeled antibody modified fluorescent particles were then spread on glass fibers to obtain fluorescent particle binding pads.

[0066] (4) Preparation of immunochromatographic reagent strips

[0067] The chromatography membrane, fluorescent particle binding pad, sample pad, and absorption pad were attached to a polyvinyl chloride base plate in a certain order. They were then cut into reagent strips and assembled with the corresponding plastic parts to form a complete reagent sheet, which was then used to obtain an immunochromatographic detection reagent sheet. The signal of the sheet was tested, and the test results are shown in Table 2 below.

[0068] Table 2. Effects of different NaN3 concentrations in the coating buffer on the CK-MB project.

[0069]

[0070] As shown in Table 2, in both PBS and PB membrane-spreading buffer systems, increasing the concentration of NaN3 in the membrane-spreading buffer significantly improved the signal of the CK-MB reagent strip, thereby increasing the discrimination and enhancing the measurement sensitivity.

[0071] Experimental Example 2

[0072] The effect of different NaN3 concentrations in the membrane application buffer on the cTnI assay.

[0073] (1) Preparation of membrane-spreading buffer

[0074] Based on the preparation of the membrane-spreading buffer provided in Example 1, multiple control groups were set up based on different concentrations of NaN3 and different buffers. The NaN3 concentrations of the PBS membrane-spreading buffer were 0%, 0.02%, 0.05%, 0.07%, and 0.1%, respectively, and the NaN3 concentrations of the PB membrane-spreading buffer were 0% and 0.02%, respectively.

[0075] (2) Preparation of chromatography membrane

[0076] The Merck nitrocellulose membrane was scratched using the above 7 scratching buffers. After scratching, the membrane was dried in a 37°C oven to obtain a chromatography membrane coated with cTnI antibody and control lines.

[0077] (3) Preparation of the binding pad

[0078] cTnI-labeled antibodies are coupled to fluorescent microspheres using chemical cross-linking and other methods to obtain fluorescent particles modified with cTnI-labeled antibodies. Then, the fluorescent particles modified with cTnI-labeled antibodies are spread on glass fibers to obtain fluorescent particle binding pads.

[0079] (4) Preparation of immunochromatographic reagent strips

[0080] The chromatography membrane, fluorescent particle binding pad, sample pad, and absorption pad were attached to a polyvinyl chloride base plate in a certain order. The strips were then cut into reagent strips and assembled with the corresponding plastic parts to form a complete reagent sheet, which was then used to test the signal of the immunochromatographic detection reagent sheet. The test results are shown in Table 3 below.

[0081] Table 3. Effects of different NaN3 concentrations in the membrane application buffer on the cTnI level.

[0082]

[0083] As shown in Table 3, in both PBS and PB membrane-spreading buffer systems, increasing the concentration of NaN3 in the membrane-spreading buffer significantly improved the signal of the cTnI reagent strip, and the low-value portion was also clearly distinguished, thus improving the measurement sensitivity.

[0084] Experimental Example 3

[0085] The effect of different KSCN concentrations on the CK-MB project.

[0086] (1) Preparation of membrane-spreading buffer

[0087] Based on the preparation of the membrane scratching buffer provided in Example 2, multiple control groups were set up based on different concentrations of KSCN and different buffers. The KSCN concentrations in the PBS membrane scratching buffer were 0%, 0.05%, 0.1%, and 0.5%, respectively, and the KSCN concentrations in the PB membrane scratching buffer were 0%, 0.05%, 0.1%, and 0.5%, respectively.

[0088] (2) Preparation of chromatography membrane

[0089] The above 8 etching buffers were used to etch Pall nitrocellulose membranes. After etching, the membranes were dried in a 37°C oven to obtain chromatographic membranes coated with CK-MB antibody (detection line) and control line.

[0090] (3) Preparation of the binding pad

[0091] The CK-MB labeled antibody was coupled to fluorescent microspheres using chemical cross-linking and other methods to obtain CK-MB labeled antibody modified fluorescent particles. The CK-MB labeled antibody modified fluorescent particles were then spread on glass fibers to obtain fluorescent particle binding pads.

[0092] (4) Preparation of immunochromatographic reagent strips

[0093] The chromatography membrane, fluorescent particle binding pad, sample pad, and absorption pad were attached to a polyvinyl chloride base plate in a certain order. The strips were then cut into reagent strips and assembled with the corresponding plastic parts to form a complete reagent sheet, which was then used to test the signal of the immunochromatographic detection reagent sheet. The test results are shown in Table 4 below.

[0094] Table 4. Effects of different KSCN concentrations in the scratching buffer on the CK-MB test.

[0095]

[0096] As shown in Table 4, similar to the addition of NaN3, increasing the concentration of KSCN in the PBS and PB membrane-spreading buffer systems significantly improved the signal of the CK-MB reagent strip, thereby increasing the discrimination and enhancing the measurement sensitivity.

[0097] Test Example 4

[0098] The effect of different KSCN concentrations on the cTnI project.

[0099] (1) Preparation of membrane-spreading buffer

[0100] Based on the preparation of the membrane scratching buffer provided in Example 2, multiple control groups were set up based on different concentrations of KSCN and different buffers. The KSCN concentrations in the PBS membrane scratching buffer were 0%, 0.05%, and 0.1%, respectively, and the KSCN concentrations in the PB membrane scratching buffer were 0%, 0.05%, and 0.1%, respectively.

[0101] (2) Preparation of chromatography membrane

[0102] Merck nitrocellulose membranes were scratched using the above six scratching buffers. After scratching, the membranes were dried in a 37°C oven to obtain a chromatography membrane coated with cTnI antibody (detection line) and control line.

[0103] (3) Preparation of the binding pad

[0104] cTnI-labeled antibodies are coupled to fluorescent microspheres using chemical cross-linking and other methods to obtain fluorescent particles modified with cTnI-labeled antibodies. Then, the fluorescent particles modified with cTnI-labeled antibodies are spread on glass fibers to obtain fluorescent particle binding pads.

[0105] (4) Preparation of immunochromatographic reagent strips

[0106] The chromatography membrane, fluorescent particle binding pad, sample pad, and absorption pad were attached to a polyvinyl chloride base plate in a certain order. The strips were then cut into reagent strips and assembled with the corresponding plastic parts to form a complete reagent sheet, which was then used to test the signal of the immunochromatographic detection reagent sheet. The test results are shown in Table 5 below.

[0107] Table 5. Effects of different KSCN concentrations in the coating buffer on the cTnI level.

[0108]

[0109] As shown in Table 5, in both PBS and PB membrane-spreading buffer systems, increasing the concentration of KSCN in the membrane-spreading buffer significantly improved the signal of the cTnI reagent strip, and the low-value portion was also clearly distinguished, thus improving the measurement sensitivity.

[0110] Experimental Example 5

[0111] The effects of different NaN3 and KSCN concentration combinations on the CK-MB project.

[0112] (1) Preparation of membrane-spreading buffer

[0113] Based on the preparation of the membrane-spreading buffer provided in Example 3, multiple control groups were set up according to buffers with different concentrations of NaN3 and KSCN. The concentrations of NaN3 and KSCN in the PBS membrane-spreading buffer were 0% / 0%, 0.02% / 0%, 0% / 0.02%, 0.02% / 0.01%, 0.02% / 0.02%, 0.04% / 0.02%, and 0.06% / 0.02%, respectively.

[0114] (2) Preparation of chromatography membrane

[0115] The above 7 types of etching buffers were used to etch Pall nitrocellulose membranes. After etching, the membranes were dried in a 37°C oven to obtain chromatographic membranes coated with CK-MB antibody (detection line) and control line.

[0116] (3) Preparation of the binding pad

[0117] The CK-MB labeled antibody was coupled to fluorescent microspheres using chemical cross-linking and other methods to obtain CK-MB labeled antibody modified fluorescent particles. The CK-MB labeled antibody modified fluorescent particles were then spread on glass fibers to obtain fluorescent particle binding pads.

[0118] (4) Preparation of immunochromatographic reagent strips

[0119] The chromatography membrane, fluorescent particle binding pad, sample pad, and absorption pad were attached to a polyvinyl chloride base plate in a certain order. The strips were then cut into reagent strips and assembled with the corresponding plastic parts to form a complete reagent sheet, which was then used to test the signal of the immunochromatographic detection reagent sheet. The test results are shown in Table 6 below.

[0120] Table 6. Effects of different NaN3 and KSCN concentrations in the coating buffer on the CK-MB project.

[0121]

[0122] As shown in Table 6, in the PBS etching buffer system, the combination of NaN3 and KSCN in the etching buffer can significantly improve the signal of the CK-MB reagent strip at a lower concentration, increase the discrimination, and improve the measurement sensitivity.

[0123] Experimental Example 6

[0124] The effect of different NaN3 and KSCN concentration combinations on the cTnI project.

[0125] (1) Preparation of membrane-spreading buffer

[0126] Based on the preparation of the membrane-spreading buffer provided in Example 3, multiple control groups were set up according to buffers with different concentrations of NaN3 and KSCN. The concentrations of NaN3 and KSCN in the PBS membrane-spreading buffer were 0% / 0%, 0.02% / 0%, 0% / 0.02%, 0.02% / 0.01%, 0.02% / 0.02%, 0.04% / 0.02%, and 0.06% / 0.02%, respectively.

[0127] (2) Preparation of chromatography membrane

[0128] The Merck nitrocellulose membrane was scratched using the above 7 scratching buffers. After scratching, it was dried in a 37°C oven to obtain a chromatography membrane coated with cTnI antibody (detection line) and control line.

[0129] (3) Preparation of the binding pad

[0130] The cTnI-labeled antibody was coupled to fluorescent microspheres by chemical cross-linking and other methods to obtain fluorescent particles modified with cTnI-labeled antibody. The fluorescent particles modified with cTnI-labeled antibody were then spread on glass fibers to obtain fluorescent particle binding pads.

[0131] (4) Preparation of immunochromatographic reagent strips

[0132] The chromatography membrane, fluorescent particle binding pad, sample pad, and absorption pad were attached to a polyvinyl chloride base plate in a certain order. The strips were then cut into reagent strips and assembled with the corresponding plastic parts to form a complete reagent sheet, which was then used to test the signal of the immunochromatographic detection reagent sheet. The test results are shown in Table 7 below.

[0133] Table 7. Effects of different NaN3 and KSCN concentrations in the coating buffer on the cTnI level.

[0134]

[0135]

[0136] As shown in Table 7, in the PBS etching buffer system, the combination of NaN3 and KSCN in the etching buffer can significantly improve the signal of cTnI reagent strips at a lower concentration, increase the discrimination, and improve the measurement sensitivity.

[0137] Experimental Example 7

[0138] The effect of different NH4SCN concentrations on the CK-MB project.

[0139] (1) Preparation of membrane-spreading buffer

[0140] Based on the preparation of the membrane-spreading buffer provided in Example 4, multiple control groups were set up based on buffers with different concentrations of NH4SCN, wherein the concentrations of NH4SCN in the PBS membrane-spreading buffer were 0%, 0.02%, 0.05%, 0.1%, 0.2%, 0.5%, and 1%, respectively.

[0141] (2) Preparation of chromatography membrane

[0142] The above 7 types of etching buffers were used to etch Pall nitrocellulose membranes. After etching, the membranes were dried in a 37°C oven to obtain chromatographic membranes coated with CK-MB antibody (detection line) and control line.

[0143] (3) Preparation of the binding pad

[0144] The CK-MB labeled antibody was coupled to fluorescent microspheres using chemical cross-linking and other methods to obtain CK-MB labeled antibody modified fluorescent particles. The CK-MB labeled antibody modified fluorescent particles were then spread on glass fibers to obtain fluorescent particle binding pads.

[0145] (4) Preparation of immunochromatographic reagent strips

[0146] The chromatography membrane, fluorescent particle binding pad, sample pad, and absorption pad were attached to a polyvinyl chloride base plate in a certain order. The strips were then cut into reagent strips and assembled with the corresponding plastic parts to form a complete reagent sheet, which was then used to test the signal of the immunochromatographic detection reagent sheet. The test results are shown in Table 8 below.

[0147] Table 8. Effects of different NH4SCN concentrations in the scratching buffer on the CK-MB test.

[0148]

[0149] As shown in Table 8, similar to the addition of NaN3, increasing the concentration of NH4SCN in the PBS etching buffer system within 0.5% significantly improved the signal of the CK-MB reagent strip, thus increasing the discrimination and improving the measurement sensitivity.

[0150] Experimental Example 8

[0151] The effect of different NH4SCN concentrations on the cTnI project.

[0152] (1) Preparation of membrane-spreading buffer

[0153] Based on the preparation of the membrane-spreading buffer provided in Example 4, multiple control groups were set up based on buffers with different concentrations of NH4SCN, wherein the concentrations of NH4SCN in the PBS membrane-spreading buffer were 0%, 0.02%, 0.05%, 0.1%, and 0.2%, respectively.

[0154] (2) Preparation of chromatography membrane

[0155] The Merck nitrocellulose membrane was scratched using the above 5 scratching buffers. After scratching, it was dried in a 37°C oven to obtain a chromatography membrane coated with cTnI antibody (detection line) and control line.

[0156] (3) Preparation of the binding pad

[0157] cTnI-labeled antibodies are coupled to fluorescent microspheres using chemical cross-linking and other methods to obtain fluorescent particles modified with cTnI-labeled antibodies. Then, the fluorescent particles modified with cTnI-labeled antibodies are spread on glass fibers to obtain fluorescent particle binding pads.

[0158] (4) Preparation of immunochromatographic reagent strips

[0159] The chromatography membrane, fluorescent particle binding pad, sample pad, and absorption pad were attached to a polyvinyl chloride base plate in a certain order. The strips were then cut into reagent strips and assembled with the corresponding plastic parts to form a complete reagent sheet, which was then used to test the signal of the immunochromatographic detection reagent sheet. The test results are shown in Table 9 below.

[0160] Table 9. Effects of different NH4SCN concentrations in the coating buffer on the cTnI level.

[0161]

[0162] As shown in Table 9, in the PBS etching buffer system, increasing the concentration of NH4SCN in the etching buffer within 0.1% significantly improved the signal of the cTnI reagent strip, and the low-value portion was also clearly distinguished, thus improving the measurement sensitivity.

[0163] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A membrane-spreading buffer solution, characterized in that, It includes: a second dissociation salt and a membrane-spreading buffer matrix, wherein the cation of the second dissociation salt is... In the membrane-spreading buffer, the mass fraction of the second dissociative salt is 0.01% to 2%.

2. The membrane-spreading buffer solution according to claim 1, characterized in that, The mass fraction of the second liquid salt is 0.01% to 1%.

3. The membrane-spreading buffer solution according to claim 2, characterized in that, The mass fraction of the second liquid salt is 0.5% to 1%.

4. The membrane-spreading buffer solution according to claim 1, characterized in that, The second liquid salt includes at least one of KSCN and NaSCN.

5. The membrane-spreading buffer solution according to claim 1, characterized in that, The second liquid salt is KSCN.

6. The membrane-spreading buffer solution according to claim 1, characterized in that, The membrane-spreading buffer also includes a first dissociation salt, which is The mass fraction of the first liquid salt is 0.1% to 2%.

7. The membrane-spreading buffer solution according to claim 6, characterized in that, The mass fraction of the first liquid salt is 0.2% to 1%.

8. The membrane-spreading buffer solution according to claim 7, characterized in that, The mass fraction of the first liquid salt is 0.5% to 1%.

9. The membrane-spreading buffer solution according to claim 6, characterized in that, When the membrane-spreading buffer includes a first ionizing salt and a second ionizing salt, the mixing mass ratio of the first ionizing salt and the second ionizing salt is (1~3):(1~3).

10. The membrane-spreading buffer solution according to claim 9, characterized in that, The mass ratio of the first liquid salt to the second liquid salt is 2:

1.

11. The membrane-spreading buffer solution according to any one of claims 1 to 10, characterized in that, The membrane-spreading buffer matrix comprises a buffer solution and an additive, wherein the additive is selected from at least one of sucrose and EDTA.

12. The membrane-spreading buffer solution according to claim 11, characterized in that, In the membrane-spreading buffer, the mass fraction of sucrose is 0.5% to 5%, and the effective concentration of EDTA is 0.1 to 5 mM.

13. The membrane-spreading buffer solution according to claim 11, characterized in that, The buffer solution is selected from any one of PBS, PB, CB, CBS, MES, and HEPES.

14. The membrane-spreading buffer solution according to claim 11, characterized in that, The pH of the buffer solution is 6.5 to 7.

5.

15. The method for preparing the membrane-spreading buffer solution according to any one of claims 1 to 14, characterized in that, It includes mixing the components of the membrane-spreading buffer.

16. The use of the second dissociative salt in the membrane-spreading buffer according to any one of claims 1 to 5 in the preparation of a membrane-spreading buffer for immunochromatographic detection.

17. A method for preparing an immunochromatographic reagent tablet, characterized in that, It includes using the membrane-spreading buffer as described in any one of claims 1 to 14 to spread the detection line antibody onto a membrane, thereby obtaining a chromatographic membrane coated with the detection line.

18. The preparation method according to claim 17, characterized in that, The method further includes using the membrane-spreading buffer as described in any one of claims 1 to 14 to spread the control line antibody onto the membrane, thereby obtaining a chromatographic membrane coated with the control line and the detection line.

19. The method for preparing the immunochromatographic reagent tablet according to claim 17, characterized in that, The preparation method further includes: sequentially attaching a sample pad, a binding pad, the chromatography membrane, and an absorbent pad to a base plate.

20. An immunochromatographic reagent tablet, characterized in that, It is prepared by the method for preparing immunochromatographic reagent tablets according to any one of claims 17 to 19.

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