Preparation method of lateral chromatography detection substrate material capable of being used for colorimetric and fluorescence signal testing

Abstract

The invention relates to the field of micro-nano machining. The invention discloses a lateral chromatography detection substrate material capable of being used for colorimetric and fluorescence signal testing, which is obtained by compounding cellulose and a polymer porous medium, preferably by depositing microcrystalline cellulose on the polymer porous medium in the form of suspension, the polymer porous medium is composed of a micro-column array and a plastic film substrate, the micro-column array is formed by a photocuring polymer, and the photocuring polymer comprises one or more of OSTE and SU-8 series photoresist. The invention also provides a preparation method of the substrate material. According to the method, the cellulose and the polymer porous medium are combined for the first time, the simple, convenient and efficient lateral chromatography detection substrate material capable of testing colorimetric signals and fluorescence signals is obtained, and the blank in the technical field is filled. The test strip prepared from the substrate material has stable flow velocity, and has high-efficiency colorimetric signal and fluorescence signal immune test performance.

Description

Technical Field

[0001] The invention relates to the field of micro-nano processing, and in particular to a method for preparing a lateral flow detection substrate material that can be used for colorimetric and fluorescent signal testing. Background Art

[0002] Lateral flow detection has a wide range of applications in the fields of biosensing, in vitro detection, environmental monitoring, food safety, etc. At present, the traditional lateral flow detection test strips on the market are mainly made of paper-based test strips (such as cellulose membranes), polymer porous media (such as upright microcolumn arrays) and other materials. These materials each have their own advantages and disadvantages. On the one hand, paper-based test strips are usually used for colorimetric signal testing and have significant colorimetric effects, but their structure is unstable, resulting in large changes in the flow rate of liquid samples, affecting the accuracy of the test results, and most of the autofluorescence signals are strong, and fluorescent signals cannot be efficiently obtained. On the other hand, polymer porous media are mostly used for fluorescent signal testing. Although their structure is relatively consistent and the flow rate of liquid samples is stable, the colorimetric signal effect is not as good as that of paper-based test strips because the polymer color is close to transparent.

[0003] In response to different testing requirements, seeking a simple and efficient test strip preparation method that can test both colorimetric signals and fluorescent signals has become an important goal in the research and application of lateral flow detection. Summary of the invention

[0004] The present invention solves the problem that the current traditional test strips cannot simultaneously and efficiently test the colorimetric signal and the fluorescent signal. In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0005] The invention provides a lateral chromatography detection substrate material which can be used for colorimetric and fluorescent signal testing, and is obtained by compounding cellulose with a polymer porous medium.

[0006] Furthermore, the microcrystalline cellulose is deposited on the polymer porous medium in the form of a suspension; the polymer porous medium is composed of a polymer microcolumn array and a plastic film substrate; and the polymer microcolumn array is formed by a photocurable polymer.

[0007] Furthermore, the polymer porous medium is provided with a colorimetric region and a fluorescent region; the microcrystalline cellulose is deposited in the colorimetric region.

[0008] Furthermore, the colorimetric area and the fluorescent area are not connected.

[0009] Furthermore, the minimum distance between the colorimetric area and the fluorescent area is at least 10 mm.

[0010] Accordingly, the present invention also provides a method for preparing the above-mentioned lateral flow detection substrate material that can be used for colorimetric and fluorescent signal testing, comprising the following steps:

[0011] A. Prepare cellulose suspension;

[0012] B. Making a mask having array microholes;

[0013] C. preparing the polymer porous medium;

[0014] D. Depositing the cellulose suspension on the polymer porous medium to obtain the lateral flow detection substrate material that can be used for colorimetric and fluorescent signal testing.

[0015] Further, step A comprises:

[0016] A-1, adding microcrystalline cellulose to an acid solution for reaction, stirring during the reaction process to obtain a mixture;

[0017] A-2. Removing the acid in the mixture in step A-1 by centrifugation or dialysis to obtain the cellulose suspension.

[0018] Furthermore, the acid solution in step A-1 includes sulfuric acid solution or hydrochloric acid solution; the usage ratio of microcrystalline cellulose to the acid solution in step A-1 includes 1.0g:10ml; the reaction temperature in step A-1 includes 45°C, and the reaction time includes 30 minutes; the dialysis method in step A-2 includes adding the mixture to a dialysis bag, and then placing the dialysis bag in deionized water.

[0019] Furthermore, the centrifugal speed in step A-2 is greater than 6000 rpm.

[0020] Furthermore, the centrifugation time in step A-2 includes 10 minutes.

[0021] Furthermore, the mass concentration of the sulfuric acid solution in step A-1 includes 38% to 64%; the mass concentration of the hydrochloric acid solution in step A-1 includes 12% to 36%; the stirring speed in step A-1 is not less than 480 rpm; in step A-2, the molecular weight cutoff of the dialysis bag is greater than 10000D, and the dialysis time is at least 8 hours.

[0022] Furthermore, the polymer porous medium is provided with a colorimetric region and a fluorescent region; in step D, the cellulose suspension in step A is deposited in the colorimetric region; step D specifically comprises the following steps:

[0023] D-1, cutting the polymer porous medium, and then performing a hydrophilic treatment to obtain a hydrophilic polymer porous medium;

[0024] D-2. Add the cellulose suspension dropwise to the hydrophilic polymer porous medium in step D-1, and after drying, obtain the lateral flow detection substrate material that can be used for colorimetric and fluorescent signal testing.

[0025] Furthermore, step C specifically includes the following steps:

[0026] C-1, a plastic film substrate and a plastic film support form a container, a liquid photocurable prepolymer is dripped into the container, and the mask is covered on the container;

[0027] C-2, curing the liquid photocurable prepolymer in step C-1 through the mask with ultraviolet light to form the polymer microcolumn array fixed on the plastic film substrate;

[0028] C-3. Develop, clean and dry the polymer microcolumn array in step C-2, and then perform post-curing treatment with ultraviolet light to obtain the polymer porous medium.

[0029] Further, in step C-1, the liquid photocurable prepolymer includes one or more of OSTE and SU-8 series photoresists; in step C-2, the polymer microcolumn array includes one or more of a polymer inclined cross microcolumn array, a polymer upright microcolumn array, and a polymer inclined microcolumn array; in the polymer microcolumn array, the diameter of the microcolumns includes 100 to 200 microns, and the spacing between the microcolumns includes 100 to 200 microns; in the polymer microcolumn array, the thickness of the microcolumns includes 100 microns to 10 mm;

[0030] When the polymer micro-column array includes one or more of the polymer inclined micro-column array and the polymer inclined cross micro-column array, the angle between the micro-column and the plastic film substrate is 15° to 75°.

[0031] Furthermore, when the polymer microcolumn array is the polymer inclined cross microcolumn array, the incident direction of the ultraviolet light in step C-2 is multi-directional and inclined to the plastic film substrate.

[0032] Furthermore, when the polymer microcolumn array is a polymer upright microcolumn array or a polymer inclined microcolumn array, the parallel ultraviolet light in step C-2 is parallel ultraviolet light.

[0033] The polymer microcolumn arrays of the present invention include but are not limited to the above-mentioned polymer inclined cross microcolumn arrays, polymer upright microcolumn arrays, and polymer inclined microcolumn arrays, and are also applicable to other polymer microcolumn arrays, such as polymer inclined non-cross microcolumn arrays.

[0034] Further, in step A, 98% of H 2SO 4 The solution is diluted with deionized water to prepare the sulfuric acid solution; and the 36% HCl solution is diluted with deionized water to prepare the hydrochloric acid solution.

[0035] Furthermore, in step A, the concentration of the sulfuric acid solution or the hydrochloric acid solution affects the density of the cellulose membrane in the finally obtained base material.

[0036] Preferably, in step A, the mass concentration of the sulfuric acid solution is 64%, and the mass concentration of the hydrochloric acid solution is 36%.

[0037] Furthermore, both SU-8 photoresist and OSTE can be used as photoresists (negative photoresists); OSTE is a homemade photoresist, and SU-8 photoresist can be a commercially available photoresist.

[0038] Furthermore, the ratio of the number of thiol groups to the number of vinyl groups in the OSTE is 1 to 1.8:1.

[0039] Further, in step C-3, the developing includes developing with propylene glycol methyl ether acetate or acetone, and the cleaning includes cleaning with isopropyl alcohol or ethanol;

[0040] Furthermore, before step D, the plastic film support is peeled off after the polymer porous medium is formed.

[0041] Furthermore, in step B, the diameter of the microholes of the mask is 100 to 200 microns, and the microhole spacing is 100 to 200 microns.

[0042] Furthermore, in step C-1, the thickness of the plastic film support is within a range of 100 micrometers to 10 millimeters.

[0043] Furthermore, when preparing a polymer inclined cross porous medium or a polymer inclined microcolumn array, in step C-2, the angle of the ultraviolet light is within a range of 15° to 75°.

[0044] Furthermore, in step C-2, the illumination intensity of the ultraviolet light is 90 μW / cm 2 , the illumination time is 10s; in step C-3, the illumination intensity of the ultraviolet light is 9μW / cm 2 , the illumination time is 3 minutes.

[0045] Furthermore, the microcolumn diameter of the microcolumn array is the same as the microhole diameter of the mask, the microcolumn spacing is the same as the microhole spacing of the mask, the microcolumn inclination angle is the same as the inclination angle of the ultraviolet light in step C-2, and the microcolumn thickness is the same as the thickness of the plastic film support.

[0046] Furthermore, the hydrophilic treatment in step D-1 includes ionic hydrophilic treatment or pre-coating the surface with Tween 20 molecules followed by drying.

[0047] Furthermore, when the size cut in step D is 6 mm x 40 mm x 0.2 mm, the amount of the dripping is 18 to 40 microliters.

[0048] Furthermore, when the size cut in step D is 6 mm x 40 mm x 0.2 mm, the area of ​​the above-mentioned dripping region is (2-10) mm x 5 mm.

[0049] Furthermore, the area of ​​the dropping region is 5 mm x 5 mm.

[0050] Furthermore, after the cellulose suspension is dripped onto the hydrophilic polymer porous medium, the cellulose suspension begins to flow under the capillary action and stops flowing after filling a certain area. The area and position of the colorimetric area are controlled by utilizing the capillary effect and controlling the amount and position of the dripping.

[0051] The present invention adopts OSTE polymer porous medium and utilizes the cellulose deposition method of the present invention to realize binding of cellulose in partial areas of the polymer porous medium, prepares lateral flow chromatography detection substrate material, and uses it to make test strips, thereby achieving: when the target to be tested is dripped onto the test strip, colorimetric detection can be used at the position where cellulose is bound (colorimetric area), and fluorescence detection can be used at the position where cellulose is not bound (fluorescent area), organically combining the advantages of the two substrates, and providing simpler and more efficient detection for lateral flow chromatography analysis.

[0052] Compared with the prior art, the present invention has the following beneficial effects:

[0053] 1. The present invention utilizes the combination of cellulose and polymer porous media for the first time to obtain a simple and efficient lateral flow detection substrate material that can test both colorimetric signals and fluorescent signals, filling the gap in this technical field.

[0054] 2. The test strip obtained by using the lateral flow detection base material of the present invention which can be used for colorimetric and fluorescent signal testing has a stable flow rate and has the immunoassay performance of efficient colorimetric signals and fluorescent signals.

[0055] 3. The present invention has strong compatibility and can adjust the parameters of the structure according to different needs, including the concentration of the cellulose suspension, the thickness of the test strip, etc.; the size and position of the colorimetric area and the fluorescent area can be easily controlled by dripping the cellulose solution using the capillary effect.

[0056] 4. The preparation method of the present invention is easy to implement, simple to operate, has high preparation efficiency, and is suitable for large-scale preparation. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 Schematic diagram of the cellulose suspension in step A of the preparation method of the present invention;

[0058] Figure 2 This is a flow chart of the preparation of the cellulose suspension in step A of the preparation method of the present invention;

[0059] Figure 3 Schematic diagram and cross-sectional diagram of the mask in step B of the preparation method of the present invention;

[0060] Figure 4 The schematic diagram of the photolithography of the polymer inclined cross micro-pillar array in step C of the preparation method of the present invention;

[0061] Figure 5 Schematic diagram and cross-sectional diagram of the polymer upright microcolumn array in step C of the preparation method of the present invention;

[0062] Figure 6 Schematic diagram and cross-sectional diagram of the polymer inclined microcolumn array in step C of the preparation method of the present invention;

[0063] Figure 7 The schematic diagram and cross-sectional diagram of the polymer porous medium test strip filled with cellulose suspension in the specific operation of step D of the preparation method of the present invention;

[0064] Figure 8 Schematic diagram of the microstructure of the lateral flow detection substrate material (polymer oblique cross microcolumn array) of the present invention, wherein ③ is a plastic film substrate;

[0065] Fig. 9 Schematic diagram of the microstructure of the lateral flow detection substrate material (polymer upright microcolumn array) of the present invention, wherein ③ is a plastic film substrate;

[0066] Figures 1 to 9 Middle: ① is cellulose suspension, ② is mask, ③ is plastic film substrate, ④ is liquid photocurable prepolymer, ⑤ is light shield, ⑥ is mirror, ⑦ is ultraviolet light, ⑧ is polymer inclined cross micro-pillar array, ⑨ is polymer upright micro-pillar array, ⑩ is polymer inclined micro-pillar array, among which ③, ④, ⑧, ⑨, ⑩ are actually transparent;

[0067] Figures 1 to 9 They are all simplified schematic diagrams and do not reflect the actual size or proportion;

[0068] Fig.10 This is a physical comparison diagram of the colorimetric area (filled part) and the fluorescent area (unfilled part) in the base material of the oblique cross porous medium of the microcrystalline cellulose partially filled with the polymer in the present invention;

[0069] Fig.11 This is a SEM image of the polymer inclined cross micro-pillar array microstructure in the present invention;

[0070] Fig.12 It is a schematic diagram of simultaneously performing colorimetric detection and fluorescence detection on a polymer porous medium test strip partially filled with microcrystalline cellulose in the present invention;

[0071] Fig.13 A fluorescence signal diagram obtained by performing a fluorescence test on a polymer porous medium test strip partially filled with microcrystalline cellulose in the present invention;

[0072] Fig.14 A colorimetric signal diagram obtained by performing a colorimetric test on a polymer porous medium test strip partially filled with microcrystalline cellulose in the present invention;

[0073] Fig.15 This is a physical picture of cellulose membrane test strips and polymer porous medium test strips. DETAILED DESCRIPTION

[0074] To make the purpose, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with specific implementation methods and drawings. Unless otherwise specified, the reagents and materials used below are conventional commercial products.

[0075] Example 1

[0076] The preparation of a lateral flow detection substrate material that can be used for colorimetric and fluorescent signal testing comprises the following steps:

[0077] Step A, preparing a cellulose suspension: slowly add 10 ml of 36% (w / w) hydrochloric acid solution to 1.0 g of microcrystalline cellulose, stir at 45° C., and stir at a speed of 480 rpm; after reacting for 30 minutes, remove the acid in the mixture by dialysis to obtain a cellulose suspension (①), such as Figure 1 As shown; wherein, the dialysis is performed using a dialysis bag with a molecular weight cutoff of 14000D, and the above mixture (cellulose-acid mixture) is added to the dialysis bag and placed in deionized water for 8 hours. The basic process of step A is as follows Figure 2 shown.

[0078] Step B, making a mask with array micropores: using AutoCAD (computer-aided design) software to design a mask pattern, design a micropore array, the micropore diameter is 150 microns, the micropore spacing is 150 microns, and make a corresponding mask (②), such as Figure 3 shown.

[0079] Step C, making a polymer porous medium: Figure 4As shown, a plastic film (③) substrate is used as a support, and a plastic film cut into a square shape is used as a support. Liquid photocurable prepolymer OSTE thiol (thiol group: vinyl group = 1.4:1) (④) is dripped into the middle of the formed container, and then a mask (②) is covered on it, and a light shielding plate (⑤) is placed on it. A photolithography machine and a mirror (⑥) are used to reflect ultraviolet light (⑦) to perform photocuring to form an inclined cross microcolumn array (⑧) of a certain height (the angle between the obtained ultraviolet light and the plastic film substrate is 15° to 75°), and the ultraviolet light intensity is 90μW / cm 2 The illumination time was 10s; then it was developed with propylene glycol methyl ether acetate, and then cleaned with isopropyl alcohol. After drying, it was post-cured with ultraviolet light. The light intensity of post-curing was 9μW / cm 2 The illumination time is 3 minutes, and the polymer oblique cross porous medium is obtained. Then the plastic film support is peeled off, and the polymer porous medium is composed of a polymer micro-column array and a plastic film substrate. The SEM image of the polymer (oblique cross) micro-column array microstructure is shown in Fig.11 shown.

[0080] The microcolumn diameter of the microcolumn array is the same as the microhole diameter of the mask, the microcolumn spacing is the same as the microhole spacing of the mask, the microcolumn tilt angle is the same as the tilt angle of the ultraviolet light in the initial curing, and the microcolumn thickness is the same as the thickness of the plastic film support.

[0081] Step D, preparing the substrate material: cutting the polymer oblique cross porous medium (⑧) obtained in step C into a size of 6 mm x 40 mm x 0.2 mm, and then subjecting it to oxygen plasma hydrophilization treatment; and then Figure 7 As shown in the filling method, the cellulose suspension (①) prepared in step A is dripped onto the colorimetric area of ​​the polymer porous medium, and the cellulose is filled by utilizing the capillary effect in the gap of the porous medium. The filling volume is 25 to 35 μl (i.e. mm 3 ), to obtain a polymer porous medium partially filled with cellulose suspension; finally, standing and drying for 5 hours, to obtain Figure 8 The lateral flow detection substrate material shown can be used for colorimetric and fluorescent signal testing. The actual comparison diagram of the colorimetric area (filled part) and the fluorescent area (unfilled part) in the substrate material of the microcrystalline cellulose partially filled polymer oblique cross porous medium is shown in Fig.10 , the upper part is the colorimetric area, and the lower part is the fluorescence area.

[0082] Example 2

[0083] The preparation of a lateral flow detection substrate material that can be used for colorimetric and fluorescent signal testing comprises the following steps:

[0084] Step A, preparing a cellulose suspension: slowly add 10 ml of 12% (w / w) hydrochloric acid solution to 1.0 g of microcrystalline cellulose, stir at 45° C., and stir at a speed of 480 rpm; after reacting for 30 minutes, remove the acid in the mixture by dialysis to obtain a cellulose suspension (①), such as Figure 1 As shown; wherein, the dialysis is performed using a dialysis bag with a molecular weight cutoff of 14000D, and the above mixture (cellulose-acid mixture) is added to the dialysis bag and placed in deionized water for 8 hours. The basic process of step A is as follows Figure 2 shown.

[0085] Step B, making a mask with array micropores: using AutoCAD (computer-aided design) software to design a mask pattern, design a micropore array, the micropore diameter is 100 microns, the micropore spacing is 100 microns, and make a corresponding mask (②), such as Figure 3 shown.

[0086] Step C, preparation of polymer porous medium: using a plastic film substrate and a plastic film cut into a square shape as a support, dripping liquid photocurable prepolymer OSTE thiol (thiol group: vinyl group = 1.6:1) in the middle, then covering the mask (②) on it, using parallel ultraviolet light of a photolithography machine (at a right angle to the plastic film substrate) to perform photocuring to form an upright microcolumn array (⑨) of a certain height, the ultraviolet light intensity is 90μW / cm 2 The exposure time is 10s; then it is developed with acetone, cleaned with isopropyl alcohol, and dried before UV post-curing. The post-curing light intensity is 9μW / cm 2 , the illumination time is 3 minutes, and the Figure 5 The polymer upright porous medium is shown. Then the plastic film support is peeled off, and the polymer porous medium is composed of the polymer micro-pillar array and the plastic film substrate.

[0087] The microcolumn diameter of the microcolumn array is the same as the microhole diameter of the mask, the microcolumn spacing is the same as the microhole spacing of the mask, the microcolumn tilt angle is the same as the tilt angle of the ultraviolet light in the initial curing, and the microcolumn thickness is the same as the thickness of the plastic film support.

[0088] Step D, preparing the substrate material: the polymer vertical porous medium (⑨) obtained in step C is cut into a size of 6 mm x 40 mm x 0.2 mm, and then subjected to oxygen plasma hydrophilization treatment; then Figure 7 As shown in the filling method, the cellulose suspension (①) prepared in step A is dripped onto the colorimetric area of ​​the polymer porous medium, and the cellulose is filled by utilizing the capillary effect in the gap of the porous medium. The filling volume is 18 to 25 μl (i.e. mm 3), to obtain a polymer porous medium partially filled with cellulose suspension; finally, standing and drying for 5 hours, to obtain Fig. 9 Lateral flow assay substrate materials shown can be used for colorimetric and fluorescent signal testing.

[0089] Example 3

[0090] The preparation of a lateral flow detection substrate material that can be used for colorimetric and fluorescent signal testing comprises the following steps:

[0091] Step A, preparing a cellulose suspension: slowly add 10 ml of 56% (w / w) sulfuric acid solution to 1.0 g of microcrystalline cellulose, stir at 45° C., and stir at a speed of 500 rpm; after reacting for 30 minutes, remove the acid in the mixture by centrifugation to obtain a cellulose suspension (①), such as Figure 1 As shown; wherein the centrifugal speed is greater than 6000rpm and the centrifugal time is 10 minutes. The basic process of step A is as follows Figure 2 shown.

[0092] Step B, making a mask with array micropores: using AutoCAD (computer-aided design) software to design a mask pattern, design a micropore array, the micropore diameter is 200 microns, the micropore spacing is 200 microns, and make a corresponding mask (②), such as Figure 3 shown.

[0093] Step C, preparation of polymer porous medium: using a plastic film substrate and a plastic film cut into a square shape as a support, dripping liquid photocurable prepolymer OSTE thiol (thiol group: vinyl group = 1.4:1) in the middle, then covering the mask (②) on it, using parallel ultraviolet light of a photolithography machine (angle of 15° to 75° with the plastic film substrate) to perform photocuring to form an inclined microcolumn array (⑩) of a certain height, the ultraviolet light intensity is 90 μW / cm 2 The illumination time is 10s; the micropillars of the array are parallel to each other and are inclined to the plastic film substrate; then the micropillars are developed with propylene glycol methyl ether acetate, washed with ethanol, and dried before UV post-curing. The post-curing light intensity is 9μW / cm 2 , the illumination time is 3 minutes, and the Figure 6 The polymer tilted porous medium is shown. Then the plastic film support is peeled off, and the polymer porous medium is composed of the polymer micro-pillar array and the plastic film substrate.

[0094] The microcolumn diameter of the microcolumn array is the same as the microhole diameter of the mask, the microcolumn spacing is the same as the microhole spacing of the mask, the microcolumn tilt angle is the same as the tilt angle of the ultraviolet light in the initial curing, and the microcolumn thickness is the same as the thickness of the plastic film support.

[0095] Step D, making a substrate material: the polymer inclined porous medium (⑩) obtained in step C is cut into a size of 6 mm x 40 mm x 0.2 mm, and then subjected to a plasma hydrophilic treatment, specifically as follows: pre-coating the surface with Tween 20 molecules (by soaking in a 0.05% Tween 20 aqueous solution and then taking it out and drying it in air); then Figure 7 As shown in the filling method, the cellulose suspension (①) prepared in step A is dripped onto the colorimetric area of ​​the polymer porous medium, and the cellulose is filled by utilizing the capillary effect in the gap of the porous medium. The filling volume is 30 to 40 μl (i.e. mm 3 ) to obtain a polymer porous medium partially filled with a cellulose suspension; and finally standing and drying for 5 hours to obtain a lateral flow detection substrate material that can be used for colorimetric and fluorescent signal testing.

[0096] Effect example

[0097] Cellulose membrane, polymer porous medium, and polymer porous medium partially filled with microcrystalline cellulose in Example 1 of the present invention (inclined cross microcolumn array) were used as different base materials, respectively. Vitamin C colorimetric reagent (concentration of 300 μg / mL) and vitamin C antibody (concentration of 50 μg / mL) were dripped onto each base material to prepare cellulose membrane test strips and polymer porous medium test strips (the actual objects of these two test strips are shown in FIG. Fig.15 As shown), a polymer porous medium test strip partially filled with microcrystalline cellulose.

[0098] The colorimetric reagent and antibody are added to the colorimetric area and fluorescence area of ​​the same base material respectively. Among them, the two signal detection areas on the test strip after adding to the polymer porous medium partially filled with microcrystalline cellulose are: colorimetric detection area and fluorescence detection area, and the division diagram is as follows Fig.12 .

[0099] Then, a liquid sample containing vitamin C was dripped onto the three test strips mentioned above, and the three test strips with liquid samples dripped were tested as follows: ① Photographed using a stereo microscope, with an exposure time of 800ms and a green channel as the color channel, and then analyzed using ImageJ software to obtain the vitamin C colorimetric signal; ② Vitamin C fluorescence signal test was performed using a fluorescence microscope, with an exposure time of 200ms and a green channel as the color channel. A schematic diagram of simultaneous colorimetric and fluorescence detection on a polymer porous medium test strip partially filled with microcrystalline cellulose is shown in Fig.12 The fluorescence signal obtained is shown in Figure 2. Fig.13 As shown in the figure, the obtained colorimetric signal is as follows Fig.14 shown.

[0100] Depend on Fig.15 as well as Fig.13 , 14The test results are analyzed as follows:

[0101] (1) For cellulose membrane test strips ( Fig.15 ), because its background color is white, it can better obtain the colorimetric signal, but the self-fluorescence signal of the base material itself is too strong, which brings a lot of noise and it is difficult to obtain the fluorescence signal of the detection target.

[0102] (2) For the polymer porous medium test strip, its low autofluorescence signal enables the immunofluorescence signal of vitamin C to be efficiently obtained, but because the polymer porous medium is close to transparent ( Fig.15 ), which makes the acquisition of colorimetric signals not as good as that of cellulose membrane test strips.

[0103] (3) For the polymer porous medium test strip filled with microcrystalline cellulose, the polymer porous medium filled with cellulose can simultaneously and efficiently obtain the colorimetric signal of vitamin C ( Fig.14 ) and immunofluorescence signals ( Fig.13 ). By utilizing the deposition method of the present invention and the OSTE polymer porous medium of the present invention, cellulose is combined in a partial area of ​​the polymer porous medium to prepare a lateral flow detection substrate material and a test strip thereof, colorimetric detection can be implemented in the area where cellulose is deposited, while fluorescence detection can be implemented in the area where cellulose is not deposited, and the detection of two different signals, colorimetric and fluorescence, can be implemented on the same lateral flow test strip.

[0104] The above disclosure is only the preferred embodiment of the present invention, which cannot be used to limit the scope of the present invention. Therefore, equivalent changes made according to the claims of the present invention are still within the scope of the present invention.

Claims

1. A lateral flow detection substrate material that can be used for colorimetric and fluorescent signal testing, characterized in that: Obtained by combining cellulose with polymer porous media.

2. The lateral flow detection substrate material for colorimetric and fluorescent signal testing according to claim 1, characterized in that: The microcrystalline cellulose is deposited on the polymer porous medium in the form of a suspension; the polymer porous medium is composed of a polymer microcolumn array and a plastic film substrate; and the polymer microcolumn array is formed by a photocurable polymer.

3. The lateral flow detection substrate material for colorimetric and fluorescent signal testing according to claim 2, characterized in that: The polymer porous medium is provided with a colorimetric area and a fluorescence area; the microcrystalline cellulose is deposited in the colorimetric area.

4. A method for preparing a lateral flow detection substrate material that can be used for colorimetric and fluorescent signal testing as claimed in claim 2, characterized in that: The steps include: A. Prepare cellulose suspension; B. Making a mask having array microholes; C. preparing the polymer porous medium; D. Depositing the cellulose suspension on the polymer porous medium to obtain the lateral flow detection substrate material that can be used for colorimetric and fluorescent signal testing.

5. The preparation method according to claim 4, characterized in that: Step A specifically includes the following steps: A-1, adding microcrystalline cellulose to an acid solution for reaction, stirring during the reaction process to obtain a mixture; A-2. Removing the acid in the mixture in step A-1 by centrifugation or dialysis to obtain the cellulose suspension.

6. The preparation method according to claim 5, characterized in that: The acid solution in step A-1 includes sulfuric acid solution or hydrochloric acid solution; the usage ratio of microcrystalline cellulose to the acid solution in step A-1 includes 1.0g:10ml; the reaction temperature in step A-1 includes 45°C, and the reaction time includes 30 minutes; the dialysis method in step A-2 includes adding the mixture to a dialysis bag, and then placing the dialysis bag in deionized water.

7. The preparation method according to claim 6, characterized in that: The mass concentration of the sulfuric acid solution in step A-1 includes 38% to 64%; the mass concentration of the hydrochloric acid solution in step A-1 includes 12% to 36%; the stirring speed in step A-1 is not less than 480rpm; in step A-2, the molecular weight cutoff of the dialysis bag is greater than 10000D, and the dialysis time is at least 8 hours.

8. The preparation method according to claim 4, characterized in that: The polymer porous medium is provided with a colorimetric area and a fluorescent area; in step D, the cellulose suspension in step A is deposited in the colorimetric area; step D specifically comprises the following steps: D-1, cutting the polymer porous medium, and then performing a hydrophilic treatment to obtain a hydrophilic polymer porous medium; D-2. Add the cellulose suspension dropwise to the hydrophilic polymer porous medium in step D-1, and after drying, obtain the lateral flow detection substrate material that can be used for colorimetric and fluorescent signal testing.

9. The preparation method according to claim 4, characterized in that: Step C specifically includes the following steps: C-1, a plastic film substrate and a plastic film support form a container, a liquid photocurable prepolymer is dripped into the container, and the mask is covered on the container; C-2, curing the liquid photocurable prepolymer in step C-1 through the mask with ultraviolet light to form the polymer microcolumn array fixed on the plastic film substrate; C-3. Develop, clean and dry the polymer microcolumn array in step C-2, and then perform post-curing treatment with ultraviolet light to obtain the polymer porous medium.

10. The preparation method according to claim 9, characterized in that: In step C-1, the liquid photocurable prepolymer includes one or more of OSTE and SU-8 series photoresists; in step C-2, the polymer microcolumn array includes one or more of a polymer inclined cross microcolumn array, a polymer upright microcolumn array, and a polymer inclined microcolumn array; in the polymer microcolumn array, the diameter of the microcolumns includes 100 to 200 microns, and the spacing between the microcolumns includes 100 to 200 microns; in the polymer microcolumn array, the thickness of the microcolumns includes 100 microns to 10 mm; When the polymer micro-column array includes one or more of the polymer inclined micro-column array and the polymer inclined cross micro-column array, the angle between the micro-column and the plastic film substrate is 15° to 75°.

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