Monomolecular array chip based on functionalized epoxy resin substrate and preparation method thereof

Abstract

The invention relates to the field of monomolecular immunodetection chips, and particularly discloses a preparation method of a monomolecular array chip based on a functionalized epoxy resin substrate, and the preparation method comprises the following steps: S1, pretreating a glass substrate to obtain a pretreated substrate; s2, the resin substrate material is heated to be molten, the temperature is maintained so that the resin substrate material can be kept in a molten state, and molten resin is obtained; s3, the surface of the pretreated substrate is evenly coated with molten resin, the coating thickness is 20-60 microns, and a coated substrate is obtained; and S4, pressing the nanoimprint mold on the surface of the coating of the coating substrate, and after the nanoimprint mold is cooled to 25 DEG C or below, removing the nanoimprint mold to obtain an imprint substrate. The single-molecule array chip has the advantages that the manufacturing cost of the single-molecule array chip can be reduced and the flexibility of the chip can be improved on the premise of ensuring high-sensitivity detection.

Description

Technical Field

[0001] The invention relates to the technical field of biological detection chips, in particular to the production technology of single molecule immune detection chips. Background Art

[0002] Single Molecule Array (SiMoA) technology is a method that uses single molecule counting to detect trace biomarkers. The detection limit of this technology can reach the order of femtogram (fg / mL), and it is currently the most representative single molecule immunoassay technology. The system is derived from a detection system developed by David Walt and David Duffy's team. Its detection principle is similar to digital PCR, and both are achieved through single molecule isolation combined with single molecule level signal amplification through a microreactor unit.

[0003] SiMoA technology is a single-molecule immunoassay based on microarray chips. It is to carve (or cast) thousands of micron-scale microwells on a millimeter-scale chip, each microwell has a volume of about 40 fl (i.e., a single-molecule array chip), and then distribute the immune complex magnetic beads in the microwells, and then count the fluorescent spots with the help of a high-resolution fluorescence microscope. According to the Poisson distribution theory, the ratio of the number of wells containing beads and fluorescent products at the same time to the total number of wells containing beads is calculated to determine the concentration of the detected substance in the test sample. The operation process is roughly as follows:

[0004] (1) using magnetic beads labeled with capture antibodies to capture antigens in the sample;

[0005] (2) labeling the captured antigen using a biotinylated detection antibody;

[0006] (3) adding streptavidin-galactosidase complex to bind to biotin on the detection antibody;

[0007] (4) The washed magnetic beads are mixed with the substrate and loaded into a single molecule array chip. The magnetic field is used to make the magnetic beads fall into microwells that are perfectly matched to their size, and an oil phase is added to physically isolate the microwells.

[0008] (5) The microwell containing galactosidase produces fluorescent products due to the catalysis of the substrate by the enzyme molecules;

[0009] (6) Performing fluorescence imaging on the microwell array and achieving quantitative detection by comparing the number of microwells emitting fluorescent signals with a standard curve.

[0010] Current SiMoA technology usually uses glass or silicon substrates as chip materials. Although these materials have good chemical stability and optical properties, they have high manufacturing costs, complex processing, and may limit detection sensitivity and the introduction of specific chemical functions in some cases. With the development of single-molecule detection technology, researchers have an urgent need for new chip materials that are more flexible, cost-effective, and can support high-sensitivity detection. Summary of the invention

[0011] In order to reduce the manufacturing cost of a single molecule array chip and improve the flexibility of the chip while ensuring high-sensitivity detection, the present invention provides a single molecule array chip based on a functionalized epoxy resin substrate and a preparation method thereof.

[0012] The technical solution adopted by the present invention is: a single molecule array chip based on a functionalized epoxy resin substrate and a preparation method thereof, wherein the production raw materials include a glass substrate and a resin substrate material, and the resin substrate material includes epoxy resin.

[0013] The present invention can be specifically implemented according to the following steps:

[0014] S1, pre-treating the glass substrate to obtain a pre-treated substrate;

[0015] S2, heating the resin base material until it is melted, and maintaining the temperature so that the resin base material remains in a molten state, to obtain a molten resin;

[0016] S3, uniformly coating the molten resin on the surface of the pretreated substrate, with a coating thickness of 20 to 60 μm, to obtain a coated substrate;

[0017] S4, pressing the nanoimprint mold onto the coating surface of the coated substrate, and after cooling to below 25° C., removing the nanoimprint mold to obtain an imprinted substrate.

[0018] Those skilled in the art will appreciate that the nanoimprint mold is a nanoimprint mold with a desired microstructure, and the mold surface should be flat and have a clear structure. When applying the molten resin, an offset printer or a manual coater can be used.

[0019] As a further improvement of the present invention, the step of immersing and modifying the imprint substrate with a hexafluoroisobutyltrimethoxysilane solution is also included. Preferably, the mass concentration of the hexafluoroisobutyltrimethoxysilane solution is 0.2% to 2.0%. Preferably, the solvent of the hexafluoroisobutyltrimethoxysilane solution is acetonitrile or acetone.

[0020] The above-mentioned immersion modification step can be implemented as follows: completely immerse the imprint substrate in the hexafluoroisobutyltrimethoxysilane solution for 3 to 20 minutes to obtain an immersion sample; then take out the immersion sample and remove the residual solvent.

[0021] Those skilled in the art will appreciate that the above method for removing the residual solvent can be performed by blowing with dry nitrogen or placing in an oven at 70° C. to 80° C. to remove the remaining solvent.

[0022] As a further improvement of the present invention, the resin base material is compounded by epoxy resin and polymethyl methacrylate in a mass ratio of 1:0.1 to 0.8.

[0023] The pretreated substrate of the present invention can be prepared according to the following steps:

[0024] A. Clean the glass substrate using an ultrasonic cleaning machine, with the ultrasonic power set to 50-100W and the cleaning time set to 5-20min;

[0025] B. Transferring the cleaned glass substrate to acetone for immersion to remove grease and organic pollutants; then using dust-free air to rinse the acetone to obtain a cleaned substrate;

[0026] C. Dry the cleaned substrate in a nitrogen stream.

[0027] As a further improvement of the present invention, in step S4, the pressure range is 2-5 MPa, the pressing temperature is 30-140° C., and the pressing time is 5-10 min.

[0028] The invention also discloses a single molecule array chip based on a functionalized epoxy resin substrate, which is prepared by the preparation method of the single molecule array chip based on a functionalized epoxy resin substrate of the invention.

[0029] The beneficial effects of the present invention are as follows: the manufacturing cost of the single molecule array chip can be reduced and the flexibility of the chip can be improved while ensuring high-sensitivity detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is an image of the single molecule array chip of Example 1 under a fluorescence microscope (Zeiss Axio Observer). DETAILED DESCRIPTION

[0031] The present invention is further described below in conjunction with embodiments.

[0032] Embodiment 1:

[0033] Prepare the single molecule array chip as follows:

[0034] (1) Clean the glass substrate using an ultrasonic cleaner with the ultrasonic power set to 100 W and the cleaning time set to 10 min;

[0035] (2) transferring the cleaned glass substrate to acetone for immersion to remove grease and organic pollutants; then using dust-free air to rinse the acetone to avoid residual water marks, thereby obtaining a cleaned substrate;

[0036] (3) Dry the cleaned substrate in a nitrogen flow to ensure that the surface is clean and dust-free to obtain a pretreated substrate.

[0037] (4) taking epoxy resin as a resin base material, heating the resin base material to 200° C. to melt it, and maintaining the temperature so that the resin base material remains in a molten state, thereby obtaining a molten resin;

[0038] (5) using an offset printing machine to uniformly coat the molten resin on the surface of the pretreated substrate, with a coating thickness of 45 μm, to obtain a coated substrate;

[0039] (6) Press a nanoimprint mold of uniform specifications (silicon is selected as the mold material, and electron beam lithography is used to prepare a square array of columnar structures with a diameter of about 5 μm and a height of 4 μm. Ensure that the mold surface has excellent smoothness and high flatness, and the accuracy and reproducibility of the structure are guaranteed by precise manufacturing processes) on the coating surface of the coated substrate, with a pressure of 3 MPa, a pressing temperature of 80°C, and a pressing time of 6 min; after cooling to 23°C, remove the nanoimprint mold to obtain an imprinted substrate.

[0040] (7) The imprinted substrate is completely immersed in a hexafluoroisobutyltrimethoxysilane solution with a mass concentration of 1.2% and the immersion time is 5 minutes to obtain an immersed sample; then the immersed sample is taken out and blown dry with dry nitrogen to remove the residual solvent to obtain a single molecule array chip.

[0041] The single molecule array chip of this example was imaged using a fluorescence microscope (Zeiss Axio Observer). Figure 1 .

[0042] Embodiment 2:

[0043] Prepare the single molecule array chip as follows:

[0044] (1) Clean the glass substrate using an ultrasonic cleaner with the ultrasonic power set to 80 W and the cleaning time set to 6 min;

[0045] (2) transferring the cleaned glass substrate to acetone for immersion to remove grease and organic pollutants; then using dust-free air to rinse the acetone to avoid residual water marks, thereby obtaining a cleaned substrate;

[0046] (3) Dry the cleaned substrate in a nitrogen flow to ensure that the surface is clean and dust-free to obtain a pretreated substrate.

[0047] (4) taking epoxy resin as a resin base material, heating the resin base material to 210° C. to melt it, and maintaining the temperature so that the resin base material remains in a molten state, thereby obtaining a molten resin;

[0048] (5) using an offset printing machine to uniformly coat the molten resin on the surface of the pretreated substrate, with a coating thickness of 50 μm, to obtain a coated substrate;

[0049] (6) Press a nanoimprint mold of uniform specifications (silicon is selected as the mold material, and electron beam lithography is used to prepare a square array of columnar structures with a diameter of about 5 μm and a height of 4 μm. Ensure that the mold surface has excellent smoothness and high flatness, and the accuracy and reproducibility of the structure are guaranteed by precise manufacturing processes) on the coating surface of the coated substrate, with a pressure of 5 MPa, a pressing temperature of 120°C, and a pressing time of 5 min; after cooling to 25°C, remove the nanoimprint mold to obtain an imprinted substrate.

[0050] (7) The imprinted substrate is completely immersed in a hexafluoroisobutyltrimethoxysilane solution with a mass concentration of 0.5% and the immersion time is 8 minutes to obtain an immersed sample; then the immersed sample is taken out and blown dry with dry nitrogen to remove the residual solvent to obtain a single molecule array chip.

[0051] Embodiment three:

[0052] This embodiment is implemented under the same conditions and steps as the first embodiment, with the only difference being that the resin base material in step (4) is compounded with epoxy resin and polymethyl methacrylate in a mass ratio of 1:0.5, and the coating thickness is kept unchanged. The specific steps are as follows:

[0053] (1) Clean the glass substrate using an ultrasonic cleaner with the ultrasonic power set to 100 W and the cleaning time set to 10 min;

[0054] (2) transferring the cleaned glass substrate to acetone for immersion to remove grease and organic pollutants; then using dust-free air to rinse the acetone to avoid residual water marks, thereby obtaining a cleaned substrate;

[0055] (3) Dry the cleaned substrate in a nitrogen flow to ensure that the surface is clean and dust-free to obtain a pretreated substrate.

[0056] (4) preparing a resin base material by compounding epoxy resin and polymethyl methacrylate in a mass ratio of 1:0.5, heating the resin base material to 200° C. to melt the resin, and maintaining the temperature so that the resin base material remains in a molten state to obtain a molten resin;

[0057] (5) using an offset printing machine to uniformly coat the molten resin on the surface of the pretreated substrate, with a coating thickness of 45 μm, to obtain a coated substrate;

[0058] (6) Press a nanoimprint mold of uniform specifications (silicon is selected as the mold material, and electron beam lithography is used to prepare a square array of columnar structures with a diameter of about 5 μm and a height of 4 μm. Ensure that the mold surface has excellent smoothness and high flatness, and the accuracy and reproducibility of the structure are guaranteed by precise manufacturing processes) on the coating surface of the coated substrate, with a pressure of 3 MPa, a pressing temperature of 80°C, and a pressing time of 6 min; after cooling to 23°C, remove the nanoimprint mold to obtain an imprinted substrate.

[0059] (7) The imprinted substrate is completely immersed in a hexafluoroisobutyltrimethoxysilane solution with a mass concentration of 1.2% and the immersion time is 5 minutes to obtain an immersed sample; then the immersed sample is taken out and blown dry with dry nitrogen to remove the residual solvent to obtain a single molecule array chip.

[0060] Comparative Example 1:

[0061] This comparative example is a control experiment of Example 1, and is implemented under the same conditions and steps as Example 1, with the only difference being that the resin substrate material is all polymethyl methacrylate and the coating thickness is kept unchanged. The specific steps are as follows:

[0062] Prepare the single molecule array chip as follows:

[0063] (1) Clean the glass substrate using an ultrasonic cleaner with the ultrasonic power set to 100 W and the cleaning time set to 10 min;

[0064] (2) transferring the cleaned glass substrate to acetone for immersion to remove grease and organic pollutants; then using dust-free air to rinse the acetone to avoid residual water marks, thereby obtaining a cleaned substrate;

[0065] (3) Dry the cleaned substrate in a nitrogen flow to ensure that the surface is clean and dust-free to obtain a pretreated substrate.

[0066] (4) taking polymethyl methacrylate as a resin base material, heating the resin base material to 200° C. to melt it, and maintaining the temperature so that the resin base material remains in a molten state, thereby obtaining a molten resin;

[0067] (5) using an offset printing machine to uniformly coat the molten resin on the surface of the pretreated substrate, with a coating thickness of 45 μm, to obtain a coated substrate;

[0068] (6) Press a nanoimprint mold of uniform specifications (silicon is selected as the mold material, and electron beam lithography is used to prepare a square array of columnar structures with a diameter of about 5 μm and a height of 4 μm. Ensure that the mold surface has excellent smoothness and high flatness, and the accuracy and reproducibility of the structure are guaranteed by precise manufacturing processes) on the coating surface of the coated substrate, with a pressure of 3 MPa, a pressing temperature of 80°C, and a pressing time of 6 min; after cooling to 23°C, remove the nanoimprint mold to obtain an imprinted substrate.

[0069] (7) The imprinted substrate is completely immersed in a hexafluoroisobutyltrimethoxysilane solution with a mass concentration of 1.2% and the immersion time is 5 minutes to obtain an immersed sample; then the immersed sample is taken out and blown dry with dry nitrogen to remove the residual solvent to obtain a single molecule array chip.

[0070] Comparative Example 2:

[0071] This comparative example is a control experiment of Example 1, and is implemented under the same conditions and steps as Example 1, except that the step of immersing and modifying the imprint substrate with a hexafluoroisobutyltrimethoxysilane solution is not included. The specific steps are as follows:

[0072] (1) Clean the glass substrate using an ultrasonic cleaner with the ultrasonic power set to 100 W and the cleaning time set to 10 min;

[0073] (2) transferring the cleaned glass substrate to acetone for immersion to remove grease and organic pollutants; then using dust-free air to rinse the acetone to avoid residual water marks, thereby obtaining a cleaned substrate;

[0074] (3) Dry the cleaned substrate in a nitrogen flow to ensure that the surface is clean and dust-free to obtain a pretreated substrate.

[0075] (4) taking epoxy resin as a resin base material, heating the resin base material to 200° C. to melt it, and maintaining the temperature so that the resin base material remains in a molten state, thereby obtaining a molten resin;

[0076] (5) using an offset printing machine to uniformly coat the molten resin on the surface of the pretreated substrate, with a coating thickness of 45 μm, to obtain a coated substrate;

[0077] (6) Pressing a nanoimprint mold of uniform specifications (silicon is selected as the mold material, and a square array of columnar structures with a diameter of about 5 μm and a height of 4 μm is prepared by electron beam lithography. Ensure that the mold surface has excellent smoothness and high flatness, and the accuracy and reproducibility of the structure are guaranteed by precise manufacturing processes) on the coating surface of the coated substrate, with a pressure of 3 MPa, a pressing temperature of 80° C., and a pressing time of 6 min; after cooling to 23° C., remove the nanoimprint mold to obtain an imprinted substrate;

[0078] (7) Blow dry the imprinted substrate with dry nitrogen to obtain a single molecule array chip.

[0079] Bioanalysis experiments of low-abundance substances:

[0080] The single molecule array chips obtained in the above embodiments and comparative examples were used in low-abundance substance bioanalysis experiments to verify their accuracy and reliability in immunoassays. The specific experimental methods are as follows:

[0081] The magnetic beads were modified with Tau217 primary antibody, and the Tau-217 secondary antibody was modified with NHS-FITC. The Tau-217 antigen of different concentrations was captured by one-step method and sandwich method. After capture, the complex was dropped on the single-molecule chip for single-molecule signal number statistical analysis. The specific experimental method is as follows:

[0082] 1. Experimental materials:

[0083] The single molecule array chips prepared in Examples 1 to 3 and Comparative Examples 1 and 2;

[0084] Tau217 primary antibody: antibody used to modify magnetic beads;

[0085] NHS-FITC: fluorescent dye used to modify Tau217 secondary antibody;

[0086] Tau217 antigen: target molecule for capture;

[0087] Magnetic beads: used to modify Tau217 primary antibody;

[0088] PBS buffer: used for dilution and washing.

[0089] 2. Experimental steps:

[0090] 1. Modification of magnetic beads:

[0091] (1) Dilute the Tau217 primary antibody to a final concentration of 10 μg / mL;

[0092] (2) Add Tau217 primary antibody to the magnetic beads to achieve an appropriate surface density and reaction temperature.

[0093] The temperature is room temperature and the reaction time is 1 hour;

[0094] 2. Modification of Tau217 secondary antibody:

[0095] (1) Dissolve NHS-FITC in PBS buffer at a concentration of 1 mg / mL;

[0096] (2) adding NHS-FITC to the Tau217 secondary antibody to form a Tau217 secondary antibody-NHS-FITC complex, the reaction temperature was room temperature, and the reaction time was 2 hours;

[0097] 3. Capture target molecules:

[0098] The Tau217 antigen solution with different concentrations (0.1 pg / mL, 0.5 pg / mL, 1 pg / mL, 10

[0099] pg / mL, 100pg / mL, 1ng / mL) were added to the modified magnetic beads, the reaction temperature was 4°C, and the reaction time was 12 hours;

[0100] 4. Application of composites:

[0101] The captured Tau217 antigen complex was dropped onto the single-molecule chip on the high-entropy alloy chip substrate, and 10 μL of the complex solution was used for each chip;

[0102] 5. Imaging analysis:

[0103] Fluorescence imaging of single-molecule chips was performed using a fluorescence microscope (Zeiss Axio Observer);

[0104] The FITC channel (excitation wavelength: 488 nm, emission wavelength: 515 nm) was used to detect and record the fluorescence signal;

[0105] The number of single-molecule signals under capture conditions of Tau217 antigen solutions with different concentrations was counted, and the results are shown in Table 1.

[0106] Table 1 Statistics of single molecule signal numbers under capture conditions of different concentrations of Tau217 antigen solutions

[0107]

[0108] It can be seen from the detection results of Examples 1 to 3 in Table 1 that the single-molecule array chip prepared by the method of the present invention can generate stable single-molecule signals under the capture conditions of Tau217 antigen solution with a concentration of 0.1 pg / mL to 1 ng / mL, verifying the accuracy and reliability of the single-molecule chip of the present invention in capturing low-abundance Tau217 antigen.

[0109] From the comparison of Example 3, Example 1, and Comparative Example 1 in Table 1, it can be seen that, under the premise that the thickness of the resin coating remains unchanged, the single-molecule signal intensity of the Tau217 antigen solution of different concentrations captured by the composite resin base material composed of epoxy resin and polymethyl methacrylate in Example 3 is significantly higher than that of Example 1 using epoxy resin alone and Comparative Example 1 using polymethyl methacrylate alone, especially at low antigen solution concentrations of 0.1pg / mL, 0.5pg / mL, and 1pg / mL, an extremely obvious sensitivity difference is shown; it can be seen that the components of the composite resin base material of the invention have a significant synergistic effect in improving the single-molecule signal intensity.

[0110] From the comparison between Example 1 and Comparative Example 2 in Table 1, it can be seen that after the imprinted substrate of Example 1 was immersed in the hexafluoroisobutyltrimethoxysilane solution, the single-molecule signal intensity captured by the Tau217 antigen solution of different concentrations was significantly higher than that of Comparative Example 2 which was not immersed under the same conditions. It can be seen that the hexafluoroisobutyltrimethoxysilane solution of the present invention has the technical effect of significantly improving the single-molecule signal intensity.

Claims

1. A method for preparing a single molecule array chip based on a functionalized epoxy resin substrate, characterized in that: The production raw materials include a glass substrate and a resin base material, and the resin base material includes epoxy resin.

2. The method for preparing a single molecule array chip based on a functionalized epoxy resin substrate according to claim 1, characterized in that: The steps include: S1, pre-treating the glass substrate to obtain a pre-treated substrate; S2, heating the resin base material until it is melted, and maintaining the temperature so that the resin base material remains in a molten state, to obtain a molten resin; S3, uniformly coating the molten resin on the surface of the pretreated substrate, with a coating thickness of 20 to 60 μm, to obtain a coated substrate; S4, pressing the nanoimprint mold onto the coating surface of the coated substrate, and after cooling to below 25° C., removing the nanoimprint mold to obtain an imprinted substrate.

3. The method for preparing a single molecule array chip based on a functionalized epoxy resin substrate according to claim 2, characterized in that: The method also includes a step of using a hexafluoroisobutyltrimethoxysilane solution to immerse and modify the imprint substrate.

4. The method for preparing a single molecule array chip based on a functionalized epoxy resin substrate according to claim 3, characterized in that: The mass concentration of the hexafluoroisobutyltrimethoxysilane solution is 0.2% to 2.0%.

5. The method for preparing a single molecule array chip based on a functionalized epoxy resin substrate according to claim 4, characterized in that: The solvent of the hexafluoroisobutyltrimethoxysilane solution is acetonitrile or acetone.

6. The method for preparing a single molecule array chip based on a functionalized epoxy resin substrate according to any one of claims 3 to 5, characterized in that: The immersion modification step is specifically as follows: completely immersing the imprint substrate in the hexafluoroisobutyltrimethoxysilane solution for 3 to 20 minutes to obtain an immersion sample; then taking out the immersion sample to remove residual solvent.

7. The method for preparing a single molecule array chip based on a functionalized epoxy resin substrate according to any one of claims 2 to 5, characterized in that: The resin base material is compounded by epoxy resin and polymethyl methacrylate in a mass ratio of 1:0.1-0.

8.

8. The method for preparing a single molecule array chip based on a functionalized epoxy resin substrate according to any one of claims 2 to 5, characterized in that: Step S1 is specifically as follows: A. Clean the glass substrate using an ultrasonic cleaning machine, with the ultrasonic power set to 50-100W and the cleaning time set to 5-20min; B. Transfer the cleaned glass substrate to acetone and soak it to remove grease and organic pollutants; Then, the acetone is rinsed away using dust-free air to obtain a cleaned substrate; C. Dry the cleaned substrate in a nitrogen stream.

9. The method for preparing a single molecule array chip based on a functionalized epoxy resin substrate according to any one of claims 2 to 5, characterized in that: In step S4, the pressure range is 2-5 MPa, the pressing temperature is 30-140° C., and the pressing time is 5-10 min.

10. A single molecule array chip based on a functionalized epoxy resin substrate prepared by the method for preparing a single molecule array chip based on a functionalized epoxy resin substrate according to any one of claims 1 to 9.

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