Colloidal gold immunochromatography detection test strip, detection card and kit

Abstract

The utility model provides a colloidal gold immunochromatography detection test strip, a detection card and a kit, the test strip comprises a strip-shaped bottom plate and a membrane layer covering the strip-shaped bottom plate, the membrane layer comprises a sample pad, a gold label pad, an NC membrane and absorbent paper which are sequentially adjacent in the axial direction of the test strip; the NC membrane is provided with a detection line and a quality control line which are parallel to the bottom edge of the test strip, are parallel to each other and are separated from each other, the detection line is positioned on one side, close to the gold label pad, of the NC membrane, and the quality control line is positioned on one side, far away from the gold label pad, of the NC membrane; non-circulation area blocks are respectively arranged at the junctions of the two side edges of the NC membrane and the two ends of the detection line, and the two non-circulation area blocks are symmetrical along the central axis of the test strip. Symmetrical non-circulation area blocks with certain areas are arranged at the two ends of the side of the detection line, so that the sensitivity of the detection line is improved, and meanwhile, the HOOK effect of the quality control line is delayed.

Description

Technical Field

[0001] The utility model relates to the technical field of immune detection, in particular to a colloidal gold immunochromatographic detection test strip, a detection card and a test kit. Background Art

[0002] Colloidal gold immunochromatography combines immunochromatography with the principle of colloidal gold color development. It is widely used due to its advantages, including small size, portability, lack of instrumentation, simple operation, on-site testing, rapid results, and the ability to visually interpret the results by observing the color of the T-line.

[0003] In recent years, numerous methods have emerged to improve the sensitivity of colloidal gold immunochromatography. Common approaches include the biotin-avidin system, enhanced labeling, and dual labeling. However, these methods are cumbersome, require high levels of operator expertise, and are cost-effective. In contrast, increasing test strip sensitivity by modifying the reaction steps or strip structure is more practical.

[0004] CN1553193A discloses a retrograde colloidal gold immunochromatographic test strip, which changes the reaction steps of traditional gold-labeled immunoassays, reduces interference from nonspecific IgG / IgM, and improves the test strip's detection sensitivity. CN201464478U discloses an improved detection device that provides a transition zone between the labeling area and the detection area to slow the flow of liquid through the detection device and improve detection sensitivity. CN201965129U discloses a novel colloidal gold immunochromatographic test strip that completely covers the sample pad on a polyester film coated with a gold-labeled antibody to improve the sensitivity of the colloidal gold product.

[0005] However, while these methods have improved sensitivity, they haven't significantly improved the color development of the quality control line's hook effect (a phenomenon in which the analyte concentration is proportional to the detection signal within a certain concentration range, but the signal decreases with increasing concentration beyond a certain concentration limit). Therefore, further improving colloidal gold immunochromatography technology remains challenging and requires further research and innovation. Utility Model Content

[0006] In order to solve the above technical problems, the purpose of the present invention is to provide a colloidal gold immunochromatographic test strip to improve the sensitivity of the test strip and delay the occurrence of the HOOK effect.

[0007] To achieve the above-mentioned objectives, the present invention provides a colloidal gold immunochromatographic test strip, which includes a strip-shaped bottom plate and a membrane layer covering the top of the strip-shaped bottom plate, wherein the membrane layer includes the following structures adjacent to each other in sequence along the axial direction of the test strip: a sample pad, a gold label pad, an NC membrane (nitrocellulose membrane) and absorbent paper, and the adjacent structures partially overlap and are fluidically connected; the NC membrane is provided with a detection line and a quality control line that are parallel to the bottom edge of the test strip and parallel to each other and spaced apart, the detection line is located on the side of the NC membrane close to the gold label pad, and the quality control line is located on the side of the NC membrane away from the gold label pad; non-circulation area blocks are respectively provided at the intersection of both sides of the NC membrane and the two ends of the detection line, and the two non-circulation area blocks are symmetrical along the central axis of the test strip.

[0008] According to a specific embodiment of the present invention, preferably, the length of the non-circulation area block along the central axis of the test strip is greater than the width of the detection line, and the non-circulation area block completely covers the detection line in the direction of the central axis of the test strip; there is a gap between the non-circulation area block and the quality control line, so that the non-circulation area block does not touch the quality control line.

[0009] According to a specific embodiment of the present invention, preferably, the sum of the widths of the two non-circulation area blocks along the detection line accounts for 1 / 3-2 / 3 of the length of the detection line.

[0010] According to a specific embodiment of the present invention, preferably, the two non-circulation area blocks have the same shape; the two non-circulation area blocks are shaped like a spindle, a rectangle, or an irregular shape. In the present invention, the combination of the non-circulation area shape and the pattern area is preferably selected to achieve optimal color development of the test line and optimal liquid migration speed after sample addition.

[0011] According to a specific embodiment of the present invention, preferably, no non-circulation area blocks are provided at both ends of the quality control line, and the length of the quality control line is the same as the width of the test strip.

[0012] According to a specific embodiment of the present invention, preferably, the non-circulation area block is a hollow structure of the NC membrane or a hydrophobic material layer covering the NC membrane.

[0013] The non-circulation area block of the present invention can be produced by methods including, but not limited to, cutting, coating, and pasting. Cutting involves mechanically punching or laser cutting the corresponding shaped portion of the NC film; coating involves applying a corresponding shaped hydrophobic material, such as insulating lacquer, to the NC film; and pasting involves pasting a corresponding shaped hydrophobic material layer, such as PET or PVC tape, onto the NC film.

[0014] According to a specific embodiment of the present invention, preferably, the distance between the test line and the quality control line is 4-6 mm; the sample pad partially covers (i.e., does not completely cover) the top of the gold label pad; the gold label pad and the absorbent paper partially cover (i.e., do not completely cover) the tops of both ends of the NC membrane.

[0015] According to a specific embodiment of the present invention, preferably, the test strip, the strip-shaped bottom plate, and the film layer are in a rectangular shape.

[0016] According to a specific embodiment of the present invention, preferably, the gold label pad is coated with colloidal gold-labeled monoclonal antibody-1, the detection line is coated with monoclonal antibody-2, and the quality control line is coated with goat anti-mouse IgG (immunoglobulin G) polyclonal antibody. In the present invention, the colloidal gold-labeled monoclonal antibody-1 coated on the gold label pad and the monoclonal antibody-2 coated on the detection line include, but are not limited to, any antibody that can form a "monoclonal antibody-1-antigen-to-be-detected" sandwich structure with the antigen to be detected.

[0017] According to a specific embodiment of the present invention, preferably, the material of the strip bottom plate is PET, PVC, PP, PE or PS.

[0018] The utility model also provides a colloidal gold immunochromatographic detection card, which includes a shell and the above-mentioned colloidal gold immunochromatographic detection test strip located inside the shell; the shell is provided with a sample addition hole and a color observation window, the sample addition hole corresponds to the sample pad of the test strip, and the color observation window corresponds to the position of the detection line and quality control line of the NC membrane of the test strip.

[0019] The utility model also provides a colloidal gold immunochromatographic detection kit, which comprises the colloidal gold immunochromatographic detection test strip or the colloidal gold immunochromatographic detection card mentioned in the claim.

[0020] The technical solution provided by the utility model has the following beneficial effects:

[0021] This utility model provides a colloidal gold immunochromatographic test strip that simply and effectively expands the detection range. By providing symmetrical, non-circulating areas of a certain area on both ends of the test line, the sensitivity of the test line is improved while also delaying the occurrence of the hook effect on the quality control line. Compared with other methods, the test strip of this utility model only requires structural changes, making it simple to prepare and low-cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a front view of the colloidal gold immunochromatographic test strip of Example 1;

[0023] Figure 21 is a side view of the colloidal gold immunochromatographic test strip of Example 1;

[0024] Figure 3 This is a front view of the colloidal gold immunochromatographic test strip of Example 2;

[0025] Figure 4 This is a front view of the colloidal gold immunochromatographic test strip of Example 3;

[0026] Figure 5 This is a front view of the colloidal gold immunochromatographic test strip of Comparative Example 1;

[0027] Figure 6a The test strips of comparative example 1 (left) and embodiment 1 (right) in the sensitivity experiment of experimental example 1 are 5×10 3 Color development of HP antigen standards in CFU / mL;

[0028] Figure 6b The test strips of Comparative Example 1 (left) and Example 1 (right) in the sensitivity experiment of Experimental Example 1 are 1×10 4 Color development of HP antigen standards in CFU / mL;

[0029] Figure 6c The test strips of comparative example 1 (left) and embodiment 1 (right) in the sensitivity experiment of experimental example 1 are 3×10 4 Color development of HP antigen standards in CFU / mL;

[0030] Figure 7 The color development of the quality control lines of the test strips of Comparative Example 1 (left) and Example 1 (right) in the HOOK effect experiment of Experimental Example 2.

[0031] Description of Figure Numbers:

[0032] 1. Strip bottom plate; 2. Sample pad; 3. Gold label pad; 4. NC membrane; 5. Absorbent paper; 6. Test line; 7. Quality control line; 8. Non-circulation area block;

[0033] L, the length of the non-circulation area block 8 along the central axis of the test strip;

[0034] D. The sum of the widths of the two non-circulation area blocks 8 along the detection line 6. DETAILED DESCRIPTION

[0035] In order to have a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be understood as limiting the scope of implementation of the present invention.

[0036] Example 1

[0037] This embodiment provides a colloidal gold immunochromatographic test strip, such as Figure 1 and Figure 2 As shown, it includes a rectangular strip bottom plate 1 and a membrane layer covering the strip bottom plate, the membrane layer includes the following structures adjacent to each other in the axial direction of the test strip: a sample pad 2, a gold label pad 3, an NC membrane 4 and an absorbent paper 5, the adjacent structures partially overlap and are fluidically connected; the sample pad 2 partially covers the top of the gold label pad 3; the gold label pad 3 and the absorbent paper 5 partially cover the top of the two ends of the NC membrane 4 respectively; the NC membrane 4 is provided with a detection line 6 and a quality control line 7 parallel to the bottom edge of the test strip and parallel to each other and spaced apart, the detection line 6 is located on the side of the NC membrane 4 close to the gold label pad 3, the quality control line 7 is located on the side of the NC membrane 4 away from the gold label pad 3, and the distance between the detection line 6 and the quality control line 7 is 5 mm; non-circulation area blocks 8 are respectively provided at the junction of the two sides of the NC membrane 4 and the two ends of the detection line 6, and the two non-circulation area blocks 8 are symmetrical along the central axis of the test strip; the two ends of the quality control line 7 No non-circulation area block 8 is provided, and the length of the quality control line 7 is the same as the width of the test strip; wherein, the width of the detection line 6 is 1 mm, the length L of the non-circulation area block 8 along the central axis of the test strip is 2.5 mm, which is greater than the width of the detection line 6 by 1 mm, and the non-circulation area block 8 completely covers the detection line 6 in the direction of the central axis of the test strip; there is a gap between the non-circulation area block 8 and the quality control line 7, and the non-circulation area block 8 does not touch the quality control line 7; the length of the detection line 6 is 3 mm, and the sum D of the widths of the two non-circulation area blocks 8 along the detection line 6 is 1.5 mm, which accounts for 1 / 2 of the length of the detection line 6 (3 mm); the two non-circulation area blocks 8 are spindle-shaped with exactly the same hollow structure; the gold label pad is coated with colloidal gold-labeled monoclonal antibody-1, the detection line 6 is coated with monoclonal antibody-2, and the quality control line 7 is coated with sheep anti-mouse IgG polyclonal antibody.

[0038] The preparation method of the colloidal gold immunochromatographic test strip comprises the following steps:

[0039] (1) Select a strip bottom plate 1 made of PVC;

[0040] (2) Spraying the gold label pad body with colloidal gold-labeled Helicobacter pylori (HP) monoclonal antibody-1 solution at a spraying volume of 5 μL / cm to prepare a gold label pad 3 coated with HP monoclonal antibody-1;

[0041] (3) Mark the test line and quality control line on the NC membrane body, and then spray 2 mg / mL HP monoclonal antibody-2 solution and goat anti-mouse IgG polyclonal antibody solution on the test line 6 and quality control line 7, respectively, with a spraying volume of 1 μL / cm;

[0042] (4) Mechanically punching the NC membrane processed in step (3) at both ends of the test line using a mold with a shuttle-shaped gap, and removing the punched portion; the quality control line is not processed in any way, thereby obtaining an NC membrane 4 with a special structure;

[0043] (5) Paste the NC membrane 4 prepared in step (4) on the strip bottom plate 1, partially cover the gold label pad 3 at one end of the NC membrane 4, and partially cover the sample pad 2 at the other end of the gold label pad 3; and partially cover the absorbent paper 5 at the other end of the NC membrane 4, so that the sample pad 2, the gold label pad 3, the NC membrane 4, and the absorbent paper 5 are finally pasted on the strip bottom plate 1 in sequence;

[0044] (6) Cutting to obtain a rectangular test strip with a width of 3 mm (the length of the quality control line 7 is the same as the width of the test strip), which is the colloidal gold immunochromatographic test strip of this embodiment.

[0045] Example 2

[0046] This embodiment provides a colloidal gold immunochromatographic test strip, which differs from embodiment 1 only in that: Figure 3 As shown, the shape of the non-circulation area block 8 is rectangular; other structures are the same as those in embodiment 1.

[0047] Example 3

[0048] This embodiment provides a colloidal gold immunochromatographic test strip, which differs from embodiment 1 only in that: Figure 4 As shown, the shape of the non-circulation area block 8 is an irregular pattern; other structures are the same as those in embodiment 1.

[0049] Comparative Example 1

[0050] This comparative example provides a colloidal gold immunochromatographic test strip, which differs from Example 1 only in that: Figure 5 As shown, the NC membrane of the test strip of this comparative example does not have the non-circulation area block 8; the other structures are the same as those of Example 1.

[0051] Experimental Example 1 Sensitivity Experiment

[0052] Take the colloidal gold immunochromatographic test strips of Example 1 and Comparative Example 1 respectively, place the two test strips on a horizontal surface, and detect 5×10 3 CFU / mL, 1×10 4 CFU / mL, 3×10 4 HP antigen standard solution at 100 CFU / mL was added 5 times at each concentration. 100 μL of HP antigen standard solution was pipetted onto the sample pads of two test strips and the results were read 15 minutes after the addition of the standard solution.

[0053] The color development of the test lines of the two test strips is as follows Figure 6a 、 Figure 6b and Figure 6c The interpretation results are shown in Table 1.

[0054] Table 1 Sensitivity test results of the test strips of Example 1 and Comparative Example 1

[0055] Group number Antigen standard concentration (CFU / mL) Comparative Example 1 Example 1 a <![CDATA[5×10 3 ]]> Overcast (0 / 5) Yang (5 / 5) b <![CDATA[1×10 4 ]]> Overcast (0 / 5) Yang (5 / 5) c <![CDATA[3×10 4 ]]> Yang (5 / 5) Yang (5 / 5)

[0056] In the table, 0 / 5 means that HP antigen was not detected in 5 tests, and 5 / 5 means that HP antigen was detected in all 5 tests.

[0057] The results showed that the sensitivity of the test strip of Example 1 was ≥5×10 3 CFU / mL, the sensitivity of the test strip of Comparative Example 1 is ≥3×10 4 CFU / mL. It can be seen that the non-circulation area block in Example 1 greatly improves the detection sensitivity of the colloidal gold immunochromatographic test strip.

[0058] Experimental Example 2: HOOK effect experiment

[0059] Take the colloidal gold immunochromatographic test strips of Example 1 and Comparative Example 1 respectively, place the two test strips on a horizontal surface, and detect 1×10 8 CFU / mL HP antigen standard, this concentration was repeated 5 times. Use a pipette to draw 100 μL of HP antigen standard solution and drop it onto the sample pad of the test paper. Read the result 15 minutes after adding the standard solution.

[0060] The color development of the two test strips is as follows Figure 7 The interpretation results are shown in Table 2.

[0061] Table 2 Quality control line color development results of the test strips of Example 1 and Comparative Example 1

[0062] Antigen standard concentration Comparative Example 1 Example 1 <![CDATA[1×10 8 CFU / mL]]> Shallow deep

[0063] The above results show that when the test strip of Example 1 tested a high-concentration antigen standard, the control line displayed a darker color, slowing the hook effect. However, when the test strip of Comparative Example 1 tested a high-concentration antigen standard, the control line displayed a lighter color, indicating a hook effect. This demonstrates that the non-circulation area in Example 1 effectively slowed the hook effect.

[0064] In summary, the present invention significantly improves the sensitivity of the test line by adding non-circulation areas at both ends of the test line, while effectively delaying the occurrence of the hook effect of the quality control line. In addition, the test paper is easy to prepare and economical.

[0065] The above embodiments are only for explaining the principle of the present invention, not for limiting the present invention. Many changes and modifications can be made to the embodiments within the spirit and scope defined by the claims of the present invention, but they will all be protected by the present invention.

Claims

1. A colloidal gold immunochromatographic test strip, characterized in that: The invention comprises a strip-shaped bottom plate and a membrane layer covering the strip-shaped bottom plate. The membrane layer comprises the following structures adjacent to each other in the axial direction of the test strip: a sample pad, a gold label pad, a NC membrane and absorbent paper. The adjacent structures partially overlap and are fluidically connected. The NC membrane is provided with a detection line and a quality control line that are parallel to the bottom edge of the test strip and parallel to each other and spaced apart. The detection line is located on the side of the NC membrane close to the gold label pad, and the quality control line is located on the side of the NC membrane away from the gold label pad. Non-circulation area blocks are respectively provided at the intersection of both sides of the NC membrane and the two ends of the detection line. The two non-circulation area blocks are symmetrical along the central axis of the test strip.

2. The colloidal gold immunochromatographic test strip according to claim 1, wherein The length of the non-circulation area block along the central axis of the test strip is greater than the width of the detection line, and the non-circulation area block completely covers the detection line in the direction of the central axis of the test strip; there is a gap between the non-circulation area block and the quality control line, so that the non-circulation area block does not touch the quality control line.

3. The colloidal gold immunochromatographic test strip according to claim 1, wherein The sum of the widths of the two non-circulation area blocks along the detection line accounts for 1 / 3 to 2 / 3 of the length of the detection line.

4. The colloidal gold immunochromatographic test strip according to claim 1, wherein The two non-circulation area blocks have the same shape; the shapes of the two non-circulation area blocks are spindle-shaped or rectangular.

5. The colloidal gold immunochromatographic test strip according to claim 1, wherein There are no non-circulation area blocks at both ends of the quality control line, and the length of the quality control line is the same as the width of the test strip.

6. The colloidal gold immunochromatographic test strip according to claim 1, characterized in that: The non-circulation area block is a hollow structure of the NC membrane or a hydrophobic material layer covering the NC membrane.

7. The colloidal gold immunochromatographic test strip according to claim 1, characterized in that: The distance between the detection line and the quality control line is 4-6 mm; the sample pad partially covers the top of the gold label pad; the gold label pad and the absorbent paper partially cover the top of both ends of the NC membrane respectively.

8. The colloidal gold immunochromatographic test strip according to claim 1, characterized in that: The gold label pad is coated with colloidal gold-labeled monoclonal antibody-1, the detection line is coated with monoclonal antibody-2, and the quality control line is coated with goat anti-mouse IgG polyclonal antibody.

9. A colloidal gold immunochromatographic test card, characterized in that: The invention comprises a shell and a colloidal gold immunochromatographic test strip according to any one of claims 1 to 8 located inside the shell; the shell is provided with a sample addition hole and a color observation window, the sample addition hole corresponds to the sample pad of the test strip, and the color observation window corresponds to the positions of the detection line and the quality control line of the NC membrane of the test strip.

10. A colloidal gold immunochromatographic detection kit, characterized in that: The invention comprises the colloidal gold immunochromatographic test strip according to any one of claims 1 to 8 or the colloidal gold immunochromatographic test card according to claim 9.

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