Electrically-driven immunochromatography test paper card based on laser-induced graphene
By using laser-induced graphene electrodes and plexiglass designs in immunochromatography test strips, the problems of long detection time and electrode corrosion in the prior art are solved, and rapid response and stable detection are achieved, suitable for scenarios requiring rapid detection. If toxic substances are detected.
Patent Information
- Application Number
- CN202411277494.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-12
- Publication Date
- 2024-12-31
AI Technical Summary
The detection time of existing immunochromatography test strips is long, and metal electrodes are prone to corrosion under high salt and high electric fields, which affects the detection results.
Laser-induced graphene is used as the electrode material, providing liquid flow driving force through electroosmoticity, combining plexiglass and wire designs to form a fast-reacting immunochromatography test paper card, solving the corrosion problem of metal electrodes and realizing the test strips and electrodes. integrated.
It shortens the detection time, improves the response speed of the test paper card, increases the service life of the electrode, and ensures the accuracy and stability of the detection results.
Smart Images
Figure CN119224294A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of immunoassay detection, and relates to an immunochromatographic test paper card, and in particular to an electrically driven immunochromatographic test paper card based on laser-induced graphene. Background Art
[0002] Immunochromatography is an immunoassay technology that uses the principle of chromatography to separate substances and uses specific particles (such as upconversion nanoparticles and fluorescent particles) to display the results. The basic principle of immunochromatography is the specific binding of antigens and antibodies. The antibody is fixed at a certain position on the nitrocellulose membrane, and the antigen that specifically binds to the antibody is used as the sample. When the antigen passes through the nitrocellulose membrane, the antigen and antibody will specifically bind, and the color of the binding site will change through the dyed marker, thereby achieving the effect of immunoassay.
[0003] The immunochromatographic test strip is a device based on the principle of immunochromatographic technology. It mainly consists of four parts. The first part is the sample pad used to absorb the sample, which has a certain water absorption capacity; the second part is the binding pad used to adsorb the dye material, such as antigens labeled with colloidal gold; the third part is the chromatographic membrane used to output the color development results. There are T lines and C lines on the chromatographic membrane, and the negative and positive of the sample are judged by color changes; the fourth part is the water-absorbing pad used to provide capillary force, which has a strong water absorption effect and absorbs the sample from the sample pad to the water-absorbing pad.
[0004] Immunochromatographic test strips can be used for immunoassays, but the current test strips have a relatively long detection time, which is basically 10 to 15 minutes. Electroosmosis is a phenomenon in which charged particles in a solution move in a directional manner relative to the capillary wall under the action of an electric field, thereby driving the entire solution to move in one direction. If electroosmosis is used, the speed at which the entire solution flows from the sample pad to the absorbent pad can be accelerated, which will shorten the detection time.
[0005] At present, the relevant research uses copper as the electrode to provide electroosmosis, and applies an electric field at both ends of the sample pad and the absorbent pad, and uses the external electric field to perform the test. The effect of the external electric field can reduce the detection time. However, this structure is not only difficult to integrate into the system to meet the actual application needs, but also copper will undergo electrochemical corrosion reaction under the action of high salt and high electric field, and the copper ions produced will inevitably cause serious interference to the detection process of the immunochromatographic test strip.
[0006] Graphene has stable performance and will not undergo chemical reactions under high voltage and high electric field, making it a good electrode material. Laser-induced graphene is a technology that can synthesize graphene on a variety of flexible film substrates through laser processing methods, and it has the advantages of simple preparation, low cost, and good scalability. The graphene induced by laser on the surface of a flexible substrate has a porous micro-nano structure, which can provide a larger specific surface area and better electrochemical properties, and is widely used in electronic devices, energy storage technology, sensors and other fields. The structural characteristics of laser-induced graphene also provide new ideas for the design of electroosmotic immunochromatography strips. Summary of the invention
[0007] In order to solve the problem of electrode preparation and integration during electroosmotic drive of immunochromatographic test strips, the present invention provides an electrically driven immunochromatographic test strip card based on laser induced graphene. The purpose of the present invention is to make the electrically driven immunochromatographic test strip have a faster response speed by changing the use of electrode materials. By establishing a new immunochromatographic test strip card structure, the test strip card is provided with a driving force for liquid flow by electroosmosis, and the electrode material connecting the power supply and the test strip adopts a laser induced graphene electrode, which solves the electrochemical reaction problem of the metal electrode, and the electrode made of laser induced graphene is very thin, which makes it easy to integrate the immunochromatographic test strip with the graphene electrode, thereby meeting the needs of practical applications.
[0008] The objective of the present invention is achieved through the following technical solutions: An electrically driven immunochromatographic test paper card based on laser-induced graphene, comprising a laser-induced graphene electrode, a test paper card shell, organic glass, a test paper strip, and a wire; The test paper card shell is divided into an upper card shell and a lower card shell, and the upper card shell and the lower card shell are fixed by an insertion tube and an insertion rod; The upper card shell is provided with a liquid adding tank and a display window, the liquid adding tank is located at the lower part of the upper card shell, corresponding to the sample pad of the test strip, and the display window is located in the middle part of the upper card shell, corresponding to the chromatographic membrane of the test strip; Organic glass is arranged inside the upper card shell, and the organic glass is respectively located above the liquid adding tank and the display window, corresponding to the binding pad and the water absorption pad of the test strip, and a laser induced graphene electrode is arranged on the surface of the organic glass, and the laser induced graphene electrode is connected to the wire, and the organic glass, the laser induced graphene electrode and the wire constitute an electrode system; The lower card shell is provided with a slot for fixing the test strip inside, and the test strip is fixed in the lower card shell through the slot; The upper card shell and the lower card shell are both provided with two test paper card wire holes, which are arranged opposite to each other and located on one side of the organic glass. The wires are led out of the test paper card through the test paper card shell wire holes and connected to a DC power supply.
[0009] Compared with the prior art, the present invention has the following advantages: 1. The present invention solves the problem of easy corrosion of traditional metal electrodes by using laser-induced graphene, which is stable, easy to prepare and low-cost, as an electrode for electroosmosis. The three-dimensional porous graphene converted from polyimide (PI) film by CO2 laser has excellent electrical properties, larger specific surface area, and is very thin as a whole. It is an excellent material for flexible electrodes and is easy to design and implement an integrated structure with test strips.
[0010] 2. The present invention designs a test strip and electrode connection system, integrates the laser-induced graphene electrode with the test strip card, and forms a rapid-response immune test strip card.
[0011] 3. The present invention uses a modified test paper card, which is convenient for disassembly of the system and makes the contact surface of the electrode and the test paper strip bear force evenly, so that the voltage provided to the test paper strip is stable and even. Compared with adhesive, this connection method does not directly contact the contact surface of the electrode and the test paper strip, reduces the possibility of damaging the electrode, and increases the service life of the electrode.
[0012] 4. The present invention produces a detection system in which a laser-induced graphene electrode is connected to a test strip, and an electric field is applied to the electrode, which provides additional power for the immunochromatography of the test strip through electroosmosis, thereby accelerating the reaction of the test strip and shortening the response time. BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Figure 1 1 is a schematic diagram of the left-side structure of an electrically driven immunochromatographic test paper card; Figure 2 It is a right view structural schematic diagram of an electrically driven immunochromatographic test paper card; Figure 3 1 is a schematic diagram of the top view of the structure of the electrically driven immunochromatographic test paper card; Figure 4 It is a schematic diagram of the structure of the upper casing viewed from above; Figure 5 1 is a schematic diagram of the top view of the lower casing; In the figure, 1. upper card shell; 2. lower card shell; 3. test paper card wire hole; 4. display window; 5. liquid adding tank; 6. wire; 7. insertion rod; 8. plexiglass; 9. laser-induced graphene electrode; 10. insertion tube; 11. test paper card slot. DETAILED DESCRIPTION
[0014] The technical solution of the present invention is further described below in conjunction with the accompanying drawings, but is not limited thereto. Any modification or equivalent replacement of the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention should be included in the protection scope of the present invention.
[0015] The present invention provides an electrically driven immunochromatographic test paper card based on laser-induced graphene, such as Figure 1~Figure 5 As shown, the test paper card includes a laser induced graphene electrode 9, a test paper card shell, organic glass 8, a test paper strip, a conductive tape, and a wire 6, wherein: The test paper card shell is divided into an upper card shell 1 and a lower card shell 2; The upper card shell 1 is provided with a liquid adding tank 6 and a display window 4 inside. The liquid adding tank 5 is located at the lower part of the upper card shell 1, corresponding to the position of the sample pad of the test strip, and is used to drip the solution to be tested and use the test strip for detection. The display window 4 is located in the middle part of the upper card shell 1, corresponding to the NC membrane of the test strip, and is used to display the T line and the C line. Six insertion rods 7 are arranged around the interior of the upper card shell 1 to fix the entire test paper card; 2 mm thick organic glass 8 is respectively arranged above the liquid adding tank 5 and the display window 4, which is used to fix the position of the laser induced graphene electrode 9 and make the pressure of the induced graphene electrode 9 equal. The laser induced graphene electrode 9 is attached to the surface of the organic glass 8 by conductive tape, and the wire 6 is fixed by conductive tape and connected to the laser induced graphene electrode 9; The organic glass 8, the laser-induced graphene electrode 9 and the wire 6 constitute an electrode system; The lower card shell 2 is mainly used to fix the test strip and connect with the upper card shell 1. A card slot 11 for fixing the test strip is provided inside the lower card shell 2. The test strip is fixed in the lower card shell 2 through the card slot 11. Six cannulas 10 are provided around the inside of the lower card shell 2. The cannulas 10 and the insertion rod 7 are designed in pairs to fix the test strip together, so as to integrate and package the laser induced graphene electrode 9 with the test strip. The upper card shell 1 and the lower card shell 2 are both provided with two test paper card wire holes 3, which are arranged opposite to each other and located on the left side of the organic glass 8. The wire 6 leads out of the test paper card through the test paper card shell wire holes 3 and is connected to a DC power supply to provide voltage for the entire system.
[0016] Through the above technical scheme, the design and implementation of the integrated structure of the laser-induced graphene electrode and the test strip are completed, and electroosmosis is used to accelerate the reaction time of the test strip. The test paper card designed by the present invention is mainly used to detect whether the tested solution contains the substance to be detected, that is, the positive solution. Since different test strips correspond to the detection of different substances and the detection speed is faster than other test strips, the test paper card designed by the present invention is mainly used in scenarios that require rapid detection, such as various toxic substance detection. Therefore, this test paper card can be used for various test strips with obvious color development, such as the new crown N protein.
[0017] In the present invention, the preparation method of the laser induced graphene electrode is as follows: a 125 μm polyimide film is used as a substrate of the laser induced graphene, and the substrate is cleaned with ethanol and deionized water; the shape of the laser induced graphene electrode is designed in CAD, and a carbon dioxide laser cutting machine is used to convert the polyimide film into three-dimensional porous graphene at a suitable power and speed to obtain a laser induced graphene electrode.
[0018] In the present invention, the electrically driven immunochromatographic test paper card is used as follows: Step 1: Preparation of laser-induced graphene electrodes: Clean the 125μm polyimide film with ethanol and deionized water, design the laser-induced graphene electrode into a rectangle with a length of 16mm and a width of 6mm in CAD, and use a carbon dioxide laser cutter to convert the polyimide film into a laser-induced graphene electrode at a suitable power and speed. Preferably, the engraving power is 16.7% and the speed is 8%; the cutting power is 60% and the speed is 8%. Prepare two sets of laser-induced graphene electrodes to serve as positive and negative electrodes.
[0019] Step 2: Preparation of the test strips to be tested: assemble the four parts of the test strips: sample pad, conjugate pad, NC membrane and absorbent pad, and cut the assembled test strips. Preferably, the test strips are cut into 70 mm in length and 20 mm in width.
[0020] Step 3: Preparation of plexiglass: Use a carbon dioxide laser cutting machine to cut the plexiglass into rectangles with a length of 16 mm and a width of 6 mm. Cut two groups to fix two groups of laser-induced graphene electrodes.
[0021] Step 4: Assemble the entire test paper card: Assemble the various parts of the test paper card according to the above structure.
[0022] Step 5. Prepare the required solutions and DC power supply: prepare the positive solution and negative solution that match the test strips, and connect the DC power supply to the wire to power the entire system.
[0023] Experimental results: Grayscale refers to the degree of brightness of each part of an object after being illuminated by a light source. The range is from 0 to 255, with white being 255 and black being 0. The smaller the grayscale value, the darker the color. According to the above implementation method, taking the Schmallenberg test strip as an example, the final grayscale value results under the negative solution and the 5ppb positive solution are shown in Table 1: Table 1 Comparison of grayscale values at different times
[0024] From Table 1, we can find that: The grayscale value of the negative solution is stable at around 160, while the grayscale value of the positive solution is lower than that of the negative solution regardless of whether a voltage is added or not. The positive solution shows normal color regardless of whether a voltage is added or not.
[0025] As time goes by, the gray value gradually decreases, that is, the color becomes darker and darker. When 10V voltage is applied to both ends of the test strip, the color is darker than when no voltage is applied, which shows the correctness of the entire test system and proves that the use of electroosmosis can indeed increase the color development and speed up the reaction time without affecting the detection performance of the test strip.
Claims
1. An electrically driven immunochromatographic test paper card based on laser-induced graphene, characterized in that The test paper card comprises a laser-induced graphene electrode, a test paper card shell, organic glass, a test paper strip, and a wire; The test paper card shell is divided into an upper card shell and a lower card shell, and the upper card shell and the lower card shell are fixed by an insertion tube and an insertion rod; The upper card shell is provided with a liquid adding tank and a display window, the liquid adding tank is located at the lower part of the upper card shell, corresponding to the sample pad of the test strip, and the display window is located in the middle part of the upper card shell, corresponding to the chromatographic membrane of the test strip; Organic glass is arranged inside the upper card shell, and the organic glass is respectively located above the liquid adding tank and the display window, corresponding to the binding pad and the water absorption pad of the test strip, and a laser induced graphene electrode is arranged on the surface of the organic glass, and the laser induced graphene electrode is connected to the wire, and the organic glass, the laser induced graphene electrode and the wire constitute an electrode system; A slot for fixing the test strip is arranged inside the lower card shell, and the test strip is fixed in the lower card shell through the slot.
2. The laser-induced graphene-based electrically driven immunochromatographic test paper card according to claim 1, characterized in that Insertion rods are arranged around the inner periphery of the upper card shell, and insertion tubes are arranged around the inner periphery of the lower card shell, and the insertion tubes and the insertion rods are designed to be matched.
3. The laser-induced graphene-based electrically driven immunochromatographic test paper card according to claim 1, characterized in that The laser-induced graphene electrode is adhered to the surface of the organic glass through a conductive tape.
4. The laser-induced graphene-based electrically driven immunochromatographic test paper card according to claim 1, characterized in that The upper card shell and the lower card shell are both provided with two test paper card wire holes, which are arranged opposite to each other and located on one side of the organic glass. The wires are led out of the test paper card through the test paper card shell wire holes and connected to a DC power supply.
5. The laser-induced graphene-based electrically driven immunochromatographic test paper card according to claim 1, characterized in that The preparation method of the laser-induced graphene electrode is as follows: a polyimide film is used as a substrate of the laser-induced graphene, and the substrate is cleaned with ethanol and deionized water; the shape of the laser-induced graphene electrode is designed in CAD, and a carbon dioxide laser cutting machine is used to convert the polyimide film into three-dimensional porous graphene to obtain the laser-induced graphene electrode.
6. The laser-induced graphene-based electrically driven immunochromatographic test paper card according to claim 5, characterized in that The thickness of the polyimide film is 125 μm.