Dual control flow type high-sensitivity immunochromatographic device

Abstract

The utility model belongs to the field of immune chromatography technology, disclose a kind of double control flow high sensitivity immune chromatography device, including bottom plate, sample pad, binding pad, dissolved breakaway isolation pad, chromatography pad and bibulous pad are sequentially arranged in sample flow direction on bottom plate, chromatography pad is sequentially provided with IgG detection line, IgM detection line and quality control line in sample flow direction, two hydrophobic isolation zones are provided on chromatography pad, one of which is located between IgG detection line and IgM detection line, another hydrophobic isolation zone is arranged between IgM detection line and quality control line, the utility model is provided with two hydrophobic isolation zones on chromatography pad, respectively between IgG detection line and IgM detection line, between IgM detection line and quality control line, using the strong hydrophobicity of polytetrafluoroethylene and the design of full coverage along the width direction, form physical barrier to block transverse flow, significantly reduce the generation of false negative, false positive result from the root, significantly improve the reliability of multiple detection.

Description

Technical Field

[0001] This utility model relates to the field of immunochromatography technology, and in particular to a dual-flow-controlled high-sensitivity immunochromatography device. Background Technology

[0002] Immunochromatographic assays, as a rapid and convenient immunoassay method, have been widely applied in various fields in recent years. The principle is based on specific antibodies or antigens immobilized on chromatographic materials such as nitrocellulose membranes. Capillary action causes the sample to migrate on the chromatographic material. During this process, the analyte in the sample specifically binds to the antibody or antigen immobilized on the membrane, forming an immune complex. This complex is then revealed by color development or labeling (such as colloidal gold or fluorescent substances), thus achieving qualitative or quantitative detection of the target substance. This technology is simple to operate, has a short detection time (typically 15-30 minutes), and requires no complex instruments, enabling on-site testing. These advantages make it highly effective in many fields, including clinical diagnosis (e.g., early pregnancy testing, infectious disease detection), food safety testing, and environmental monitoring.

[0003] However, traditional immunochromatography techniques still reveal some problems that urgently need to be addressed in practical applications. In multiplexing scenarios, the issue of sample cross-contamination becomes increasingly prominent. Taking the common IgG / IgM assay as an example, cross-interference between samples can easily lead to false negative results, severely affecting the reliability and accuracy of the assay. This is because, during immunochromatography, sample liquids from different detection areas may cross-flow due to various factors, causing non-specific binding of labeled antibodies to the target analyte in different detection areas, thus interfering with the normal detection signal and leading to erroneous test results.

[0004] To address this, a dual-flow-controlled high-sensitivity immunochromatographic device is proposed. Utility Model Content

[0005] The purpose of this invention is to provide a dual-flow-controlled high-sensitivity immunochromatographic device, thereby solving or at least alleviating one or more of the aforementioned problems and other issues existing in the prior art.

[0006] To achieve the above objectives, the main technical solutions adopted by this utility model include:

[0007] A dual-flow-controlled high-sensitivity immunochromatographic device includes a base plate. A sample pad, a conjugation pad, a dissolution isolation pad, a chromatography pad, and an absorbent pad are sequentially arranged on the base plate along the sample flow direction. An IgG detection line, an IgM detection line, and a control line are sequentially arranged on the chromatography pad along the sample flow direction. Two hydrophobic isolation bands are provided on the chromatography pad, one of which is located between the IgG and IgM detection lines, and the other is located between the IgM detection line and the control line.

[0008] In a dual-flow-controlled high-sensitivity immunochromatographic apparatus according to the present invention, the hydrophobic isolation strip is a polytetrafluoroethylene isolation strip, the hydrophobic isolation strip permeates the surface of the chromatography pad by 10-20 μm, and the hydrophobic isolation strip fully covers the chromatography pad along its width direction.

[0009] In a dual-flow-controlled high-sensitivity immunochromatographic apparatus according to the present invention, the surface thicknesses of the IgG detection line permeation chromatography pad, the IgM detection line permeation chromatography pad, and the quality control line permeation chromatography pad are equal and all greater than the surface thickness of the hydrophobic isolation zone permeation chromatography pad.

[0010] In a dual-flow-controlled high-sensitivity immunochromatographic apparatus according to the present invention, the dissolution isolation pad is a water-soluble cellulose membrane, the dissolution isolation pad overlaps the conjugation pad by 1-2 mm along the sample flow direction, the dissolution isolation pad overlaps the chromatography pad by 1-1.5 mm, and the dissolution time of the dissolution isolation pad is 4.5-5.5 min.

[0011] In a dual-flow-controlled high-sensitivity immunochromatographic apparatus according to the present invention, the sample pad is a glass fiber membrane, and the sample pad overlaps the conjugate pad by 1-3 mm.

[0012] In a dual-flow-controlled high-sensitivity immunochromatographic apparatus according to the present invention, the conjugate pad is a polyethylene terephthalate membrane, and the conjugate pad is provided with two independent coating regions, one coating region being coated with quantum dot-labeled antibody and the other coating region being coated with colloidal gold-labeled antibody.

[0013] In a dual-flow-controlled high-sensitivity immunochromatographic apparatus according to the present invention, the chromatography pad is a nitrocellulose membrane with a thickness of 80-120 μm.

[0014] In a dual-flow-controlled high-sensitivity immunochromatographic apparatus according to the present invention, the absorbent pad is absorbent paper, and the absorbent pad overlaps the chromatography pad by 1-3 mm.

[0015] In a dual-flow-controlled high-sensitivity immunochromatographic apparatus according to the present invention, the base plate is a PVC board.

[0016] According to the present invention, a dual-flow-controlled high-sensitivity immunochromatographic apparatus further includes a housing, a base plate fixed inside the housing, and a sample application hole for applying a sample to a sample pad and an observation hole for observing the detection results on the chromatography pad.

[0017] This utility model has at least the following beneficial effects:

[0018] By setting two hydrophobic isolation bands on the chromatography pad, located between the IgG and IgM detection lines and between the IgM detection line and the control line respectively, the strong hydrophobicity of polytetrafluoroethylene and its full-coverage design along the width direction form a physical barrier to block lateral cross-flow. At the same time, the hydrophobic isolation bands only penetrate 10-20μm into the surface of the chromatography pad, while the penetration thickness of the detection lines and control lines is greater. This avoids cross-interference between regions and does not affect the longitudinal sample flow and reaction, thereby reducing the generation of false negative and false positive results from the root and significantly improving the reliability of multiplex detection.

[0019] Sensitivity is optimized through a dual design: Firstly, the dissolution isolation pad uses a water-soluble cellulose membrane, whose 4.5-5.5 min dissolution time ensures that the sample reacts fully with the quantum dot-labeled antibody and colloidal gold-labeled antibody in the conjugation pad, forming more complexes before entering the chromatography pad. Secondly, the dual-labeling system of the conjugation pad enhances the detection signal through signal superposition, especially the high fluorescence intensity of the quantum dot-labeled antibody, which significantly improves the recognition ability of low-concentration targets. Furthermore, the 80-120 μm thickness of the chromatography pad provides ample space for the reaction, further ensuring the specific binding efficiency of the antibody and the target, resulting in a significant improvement in detection sensitivity compared to traditional techniques.

[0020] The system employs a dual flow control mechanism of "spatial isolation + time regulation": the spatial isolation of the hydrophobic isolation zone achieves physical separation of the detection area, avoiding lateral interference; the dissolution time control of the dissolution isolation pad enables time regulation of sample entry into the chromatography pad, ensuring that the sample reacts fully with the labeled antibody before chromatography. This dual flow control design not only solves the problem of "uncontrollable flow rate leading to insufficient reaction" in traditional technologies, but also improves the accuracy of the detection process by optimizing the gradient process to make the reaction conditions of different detection zones more suitable for the characteristics of their respective target analytes. Attached Figure Description

[0021] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0022] Figure 1 This is a schematic diagram of the structure of this utility model;

[0023] Figure 2 This is a schematic diagram of the structure of this utility model after the housing is installed.

[0024] Explanation of icon numbers:

[0025] 1. Sample pad; 2. Binding pad; 3. Dissolution isolation pad; 4. Chromatography pad; 5. Absorbent pad; 6. IgG detection line; 7. IgG detection line; 8. Quality control line; 9. Hydrophobic isolation band; 10. Base plate; 11. Shell; 1101. Sample dispensing port; 1102. Observation port. Detailed Implementation

[0026] The following will describe in detail the implementation of this application with reference to the accompanying drawings and embodiments, so that the implementation process of how this application uses technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly.

[0027] Please refer to Figures 1 to 2 As shown in the embodiments of this utility model,

[0028] A dual-flow-controlled high-sensitivity immunochromatographic apparatus includes a base plate 10. A sample pad 1, a binding pad 2, a dissolution isolation pad 3, a chromatography pad 4, and an absorbent pad 5 are sequentially arranged on the base plate 10 along the sample flow direction. An IgG detection line 6, an IgM detection line 7, and a control line 8 are sequentially arranged on the chromatography pad 4 along the sample flow direction. Two hydrophobic isolation bands 9 are provided on the chromatography pad 4, one of which is located between the IgG detection line 6 and the IgM detection line 7, and the other is located between the IgM detection line 7 and the control line 8.

[0029] After the sample is dropped onto sample pad 1, it flows sequentially through conjugation pad 2, dissolving isolation pad 3, and chromatography pad 4 under capillary action, and is finally absorbed by absorbent pad 5. The labeled antibody in conjugation pad 2 binds to the target substance in the sample, forming a complex. Dissolving isolation pad 3 controls the time it takes for the sample to enter chromatography pad 4, ensuring a sufficient reaction between the sample and the labeled antibody in conjugation pad 2. The IgG detection line 6 and IgM detection line 7 on chromatography pad 4 are immobilized with antibodies that specifically bind to their respective target substances, and the control line 8 is used to determine the validity of the detection. Two hydrophobic isolation bands 9 prevent lateral flow of the sample on chromatography pad 4, avoiding interference between the IgG detection line 6, IgM detection line 7, and control line 8, achieving spatial isolation flow control in dual flow control and improving detection accuracy.

[0030] In this embodiment, the hydrophobic isolation strip 9 is a polytetrafluoroethylene isolation strip, which permeates 10-20 μm into the surface of the chromatography pad 4 and fully covers the width of the chromatography pad 4.

[0031] Polytetrafluoroethylene (PTFE) possesses strong hydrophobicity, effectively blocking the lateral flow of sample liquid on the chromatography pad 4 as a hydrophobic isolation band 9. Its penetration depth is 10-20 μm into the surface of the chromatography pad 4, ensuring isolation without excessive penetration that could affect the normal capillary action of the chromatography pad 4. The design, which fully covers the width of the chromatography pad 4, completely blocks lateral sample cross-flow between different detection areas, further enhancing spatial isolation and preventing detection errors caused by cross-contamination.

[0032] In this embodiment, the surface thicknesses of the IgG detection line 6 permeation chromatography pad 4, the IgM detection line 7 permeation chromatography pad 4, and the quality control line 8 permeation chromatography pad 4 are equal and all greater than the surface thickness of the hydrophobic isolation band 9 permeation chromatography pad 4.

[0033] The IgG test line 6, IgM test line 7, and control line 8 have equal thicknesses on the surface of the chromatography pad 4, ensuring consistent binding conditions with their corresponding substances in the sample and making the detection signals comparable. Furthermore, their penetration thickness is greater than that of the hydrophobic isolation band 9, ensuring sufficient distribution depth of antibodies or antigens in the test lines and control lines within the chromatography pad 4 for adequate reaction with the longitudinally flowing sample. This also prevents the presence of the hydrophobic isolation band 9 from affecting the normal binding of the test lines and control lines to the sample, thus guaranteeing the intensity and specificity of the detection signal.

[0034] In this embodiment, the dissolution isolation pad 3 is a water-soluble cellulose membrane. The dissolution isolation pad 3 overlaps with the conjugation pad 2 by 1-2 mm along the sample flow direction, and overlaps with the chromatography pad 4 by 1-1.5 mm. The dissolution time of the dissolution isolation pad 3 is 4.5-5.5 min.

[0035] The dissolution isolation pad 3 is made of water-soluble cellulose membrane, which gradually dissolves under the influence of the sample liquid. It overlaps with the conjugation pad 2 by 1-2 mm and with the chromatography pad 4 by 1-1.5 mm, ensuring smooth sample transfer from the conjugation pad 2 to the dissolution isolation pad 3. After the dissolution isolation pad 3 dissolves, the sample then enters the chromatography pad 4. The dissolution time of 4.5-5.5 minutes allows the sample to fully react with the labeled antibody in the conjugation pad 2 to form a complex before entering the chromatography pad 4, improving detection sensitivity. Simultaneously, by controlling the time it takes for the sample to enter the chromatography pad 4, time-controlled flow is achieved, optimizing the detection process.

[0036] In this embodiment, the sample pad 1 is a glass fiber membrane, and the sample pad 1 overlaps the conjugate pad 2 by 1-3 mm.

[0037] Glass fiber membranes possess excellent water absorption and sample filtration capabilities. As sample pad 1, they can rapidly adsorb samples and perform preliminary filtration of impurities in the samples, preventing impurities from affecting subsequent detection. Sample pad 1 overlaps with conjugate pad 2 by 1-3 mm, ensuring that the sample can be smoothly transferred from sample pad 1 to conjugate pad 2 by capillary action, guaranteeing sufficient contact between the sample and the labeled antibody in conjugate pad 2, laying the foundation for subsequent reactions.

[0038] In this embodiment, the binding pad 2 is a polyethylene terephthalate membrane, and the binding pad 2 is provided with two independent coating regions, one of which is coated with quantum dot-labeled antibody, and the other coating region is coated with colloidal gold-labeled antibody.

[0039] Polyethylene terephthalate (PET) membranes exhibit good stability and adsorption properties, making them suitable as carriers for labeled antibodies in conjugate pad 2. Two independent coating regions are coated with quantum dot-labeled antibodies and colloidal gold-labeled antibodies, respectively, avoiding interference between the two types of labeled antibodies. Quantum dot-labeled antibodies are characterized by high fluorescence intensity and good stability, while colloidal gold-labeled antibodies show color development visible to the naked eye. Using both in combination improves the sensitivity and accuracy of detection, simultaneously meeting different detection needs, such as quantitative and qualitative assays.

[0040] In this embodiment, the chromatography pad 4 is a nitrocellulose membrane with a thickness of 80-120 μm.

[0041] Nitrocellulose membranes possess excellent capillary action and protein adsorption capabilities, making them ideal for use as the core region in immunochromatographic reactions. With a thickness of 80-120 μm, they provide sufficient space for the IgG detection line 6, IgM detection line 7, and control line 8, while ensuring a suitable flow rate of the sample within the membrane. This allows the target substances in the sample ample time to bind with the antibodies or antigens in the detection and control lines, ensuring a complete detection reaction.

[0042] In this embodiment, the absorbent pad 5 is absorbent paper, and the absorbent pad 5 overlaps the chromatography pad 4 by 1-3 mm.

[0043] The absorbent paper has a strong water absorption capacity. As the absorbent pad 5, it can provide a continuous driving force for the flow of the sample in the chromatography pad 4 under capillary action, allowing the sample to successfully complete the entire chromatography process. It overlaps with the chromatography pad 4 by 1-3 mm, which can ensure that the sample can smoothly enter the absorbent pad 5 from the chromatography pad 4, avoid the accumulation of sample at the end of the chromatography pad 4, and ensure the continuity and stability of the detection process.

[0044] In this embodiment, the base plate 10 is a PVC board.

[0045] PVC board has good rigidity, stability and corrosion resistance. As a base plate 10, it can support and fix the sample pad 1, binding pad 2, dissolution isolation pad 3, chromatography pad 4 and absorbent pad 5, ensuring the stability of each component during the detection process and avoiding the impact of component displacement on sample flow and the accuracy of detection results. At the same time, the chemical stability of PVC board can prevent it from reacting with the sample or test reagent, ensuring the reliability of the detection environment.

[0046] In this embodiment, a housing 11 is also included, and a base plate 10 is fixed inside the housing 11. The housing 11 is provided with a sample addition hole 1101 for adding samples to the sample pad 1 and an observation hole 1102 for observing the detection results on the chromatography pad 4.

[0047] The housing 11 protects the internal base plate 10 and all components, preventing external environmental factors from interfering with the detection process. The sample application port 1101 facilitates the addition of samples to the sample pad 1, ensuring the accuracy and convenience of the application operation. The observation port 1102 allows operators to directly observe the color development of the IgG detection line 6, IgM detection line 7, and control line 8 on the chromatography pad 4, enabling rapid reading of test results and improving the convenience of the detection process.

[0048] The foregoing description illustrates and describes several preferred embodiments of the present invention. However, as previously stated, it should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the present invention's conception through the foregoing teachings or related technical or knowledge. Any modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. A dual-flow-controlled high-sensitivity immunochromatographic device, characterized in that, The system includes a base plate (10), on which a sample pad (1), a conjugation pad (2), a dissolution isolation pad (3), a chromatography pad (4), and an absorbent pad (5) are arranged sequentially along the sample flow direction. On the chromatography pad (4), an IgG detection line (6), an IgM detection line (7), and a control line (8) are arranged sequentially along the sample flow direction. On the chromatography pad (4), two hydrophobic isolation bands (9) are arranged, one of which is located between the IgG detection line (6) and the IgM detection line (7), and the other is located between the IgM detection line (7) and the control line (8).

2. The dual-flow-controlled high-sensitivity immunochromatographic apparatus according to claim 1, characterized in that: The hydrophobic isolation strip (9) is a polytetrafluoroethylene isolation strip. The hydrophobic isolation strip (9) permeates 10-20 μm of the surface of the chromatography pad (4) and fully covers the width of the chromatography pad (4).

3. The dual-flow-controlled high-sensitivity immunochromatographic apparatus according to claim 2, characterized in that: The surface thickness of the IgG detection line (6) permeation chromatography pad (4), the surface thickness of the IgM detection line (7) permeation chromatography pad (4), and the surface thickness of the quality control line (8) permeation chromatography pad (4) are equal and all greater than the surface thickness of the hydrophobic isolation zone (9) permeation chromatography pad (4).

4. The dual-flow-controlled high-sensitivity immunochromatographic apparatus according to claim 1, characterized in that: The dissolution isolation pad (3) is a water-soluble cellulose membrane. The dissolution isolation pad (3) overlaps the conjugate pad (2) by 1-2 mm along the sample flow direction. The dissolution isolation pad (3) overlaps the chromatography pad (4) by 1-1.5 mm. The dissolution time of the dissolution isolation pad (3) is 4.5-5.5 min.

5. The dual-flow-controlled high-sensitivity immunochromatographic apparatus according to claim 1, characterized in that: The sample pad (1) is a glass fiber membrane, and the sample pad (1) overlaps the conjugate pad (2) by 1-3 mm.

6. The dual-flow-controlled high-sensitivity immunochromatographic apparatus according to claim 1, characterized in that: The conjugate pad (2) is a polyethylene terephthalate membrane. The conjugate pad (2) has two independent coating regions, one of which is coated with quantum dot-labeled antibody and the other is coated with colloidal gold-labeled antibody.

7. The dual-flow-controlled high-sensitivity immunochromatographic apparatus according to claim 1, characterized in that: The chromatography pad (4) is a nitrocellulose membrane with a thickness of 80-120 μm.

8. The dual-flow-controlled high-sensitivity immunochromatographic apparatus according to claim 1, characterized in that: The absorbent pad (5) is absorbent paper, and the absorbent pad (5) overlaps the chromatography pad (4) by 1-3 mm.

9. The dual-flow-controlled high-sensitivity immunochromatographic apparatus according to claim 1, characterized in that: The base plate (10) is a PVC board.

10. A dual-flow-controlled high-sensitivity immunochromatographic apparatus according to any one of claims 1-9, characterized in that: It also includes a housing (11), the base plate (10) is fixed inside the housing (11), and the housing (11) is provided with a sample addition hole (1101) for adding sample to the sample pad (1) and an observation hole (1102) for observing the detection results on the chromatography pad (4).

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