Glucose colorimetric-SERS dual-mode sensor based on MCOF and preparation method and application thereof
By constructing a core-shell structure Fe3O4@COF@Au(GOx) based on a magnetic covalent organic framework, and combining colorimetric and SERS techniques, the problems of low sensitivity and environmental interference in existing glucose detection methods were solved, achieving high sensitivity and selectivity for glucose detection.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- DEZHOU UNIV
- Filing Date
- 2025-12-01
- Publication Date
- 2026-04-17
AI Technical Summary
Among existing glucose detection methods, colorimetric detection is easily affected by external environmental interference and has low sensitivity, while SERS technology has low affinity for glucose molecules due to uncontrolled nanoparticle distribution, making it difficult to achieve efficient detection.
A core-shell structure Fe3O4@COF@Au(GOx) based on a magnetic covalent organic framework (MCOF) was adopted. A magnetic covalent organic framework material was constructed with Fe3O4 as the core, and gold nanoparticles and glucose oxidase were grown on its surface to form a core-shell structure, enabling colorimetric-SERS dual-mode detection of glucose.
It improves the stability of the SERS substrate and the affinity of glucose molecules, realizes colorimetric-SERS dual-mode detection, enhances the sensitivity and selectivity of glucose detection, and enables efficient detection in the range of 50nM-500µM.
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Figure CN121877844A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the technical field of glucose detection, specifically relating to a glucose colorimetric-SERS dual-mode sensor based on MCOF, its preparation method, and its application. Background Technology
[0002] Glucose is one of the most important metabolic products in the human body, playing a vital role in bodily functions. Both excessively high and low glucose levels can seriously affect health. High glucose levels, leading to diabetes, can increase the risk of cardiovascular disease, lung damage, kidney disease, and even blindness. Therefore, developing rapid, sensitive, and non-invasive glucose detection methods is of great significance for the early diagnosis and control of diabetes.
[0003] Colorimetric detection is the easiest detection method to identify molecules, but its sensitivity is relatively low. Surface-enhanced Raman scattering (SERS) has the highest specificity and sensitivity for molecular recognition and detection, making it the most promising method for detecting trace biomolecules.
[0004] Currently, colorimetric detection methods are easily affected by external environmental interference, resulting in relatively low detection sensitivity. SERS technology, due to the uncontrolled distribution of nanoparticles, exhibits low affinity for glucose molecules. Therefore, constructing a colorimetric-SERS dual-mode glucose detection method based on a magnetic covalent organic framework can complement these methods, improving the stability of the SERS substrate and the affinity for glucose molecules. This is of great significance for glucose detection. Summary of the Invention
[0005] The main objective of this invention is to overcome the shortcomings and deficiencies of the prior art and to provide a glucose colorimetric-SERS dual-mode sensor based on MCOF, its preparation method, and its application.
[0006] To achieve the above objectives, the present invention adopts the following technical solution: One aspect of the present invention provides a method for preparing a glucose detection SERS sensor based on a magnetic covalent organic framework, comprising the following steps: Preparation of gold nanoparticles and Fe3O4 nanoparticles; Fe3O4 nanoparticles were prepared into a suspension and reacted with TPAB solution, DMTP solution and acetic acid solution to obtain Fe3O4@COF composite material; Fe3O4@COF composite material was prepared into a suspension and reacted sequentially with gold nanoparticles and GOx to obtain Fe3O4@COF@Au(GOx).
[0007] As a preferred technical solution, gold nanoparticles are prepared by reacting an aqueous solution of chloroauric acid with a sodium citrate solution, specifically as follows: 50 mL of 0.01 wt% chloroauric acid aqueous solution was heated to boiling with stirring, and 0.50 mL of 1.0 wt% sodium citrate solution was immediately added as a reducing agent to obtain gold nanoparticles.
[0008] As a preferred technical solution, Fe3O4 nanoparticles are prepared using FeCl3·6H2O, specifically as follows: FeCl3·6H2O was dissolved in 50 mL of ethylene glycol, NaAc was added and stirred for 30 minutes, and then reacted in a polytetrafluoroethylene-lined autoclave at 200°C for 8 hours to obtain Fe3O4 nanoparticles with a particle size of 150 nm to 300 nm.
[0009] As a preferred technical solution, the Fe3O4 nanoparticles are prepared into a suspension and reacted with TPAB solution, DMTP solution and acetic acid solution to obtain Fe3O4@COF composite material, specifically as follows: The synthesized Fe3O4 nanoparticles were ultrasonically dispersed in acetonitrile, and TPAB and DMTP were dissolved in 10 mL of acetonitrile to prepare Fe3O4 suspensions. After mixing the Fe3O4 suspension with TPAB and DMTP solutions under mechanical stirring at 300-1000 rpm for 5-30 minutes, add 3-20 mL of 12M acetic acid solution and let it stand for 72 hours. The resulting dark gray-green Fe3O4@COF composite material is then vacuum dried at 60 degrees Celsius and stored for later use.
[0010] As a preferred technical solution, the Fe3O4@COF composite material is prepared into a suspension and reacted sequentially with gold nanoparticles and GOx, specifically as follows: 5.0 mg of Fe3O4@COF composite material was ultrasonically dispersed in 5 mL of a mixed solvent of ethanol / water with a volume ratio of 1:0.5-2. Add 30-50 nm gold nanoparticles to the Fe3O4@COF suspension; after the reaction is complete, collect Fe3O4@COF@Au by magnetic separation, and then wash the residual reagents three times with ultrapure water; Fe3O4@COF@Au was dispersed in 5 mL of ultrapure water; Mix 100 μL of GOx at a concentration of 1-4 mg / mL with Fe3O4@COF@Au and react for 10-40 minutes to obtain Fe3O4@COF@Au(GOx) as a spare sample.
[0011] In another aspect, the present invention provides a glucose detection SERS sensor based on a magnetic covalent organic framework, with the chemical formula Fe3O4@COF@Au(GOx), which is prepared by the aforementioned method for preparing a glucose detection SERS sensor based on a magnetic covalent organic framework.
[0012] Another aspect of the present invention provides a method for detecting glucose using a colorimetric-SERS dual-mode method, comprising the following steps: The SERS sensor for glucose detection based on a magnetic covalent organic framework as described in claim 6 was placed in a centrifuge tube, and a colorimetric solution, a buffer solution, and a glucose solution to be tested were added to the centrifuge tube in sequence to carry out the reaction. Immediately after the reaction, the absorbance at 655 nm was measured using a UV-Vis spectrophotometer, and the Raman signal was simultaneously acquired using a 785 nm laser Raman spectrometer to plot the working curve.
[0013] As a preferred technical solution, the volume of the glucose detection SERS sensor based on the magnetic covalent organic framework added is 50-200µL, the colorimetric solution added is 100-200µL of TMB colorimetric solution, the buffer solution added is 1mL of NaAc-HAc buffer solution with pH=4, the volume of the glucose solution to be tested added is 200µL, and the reaction time is 25min.
[0014] Compared with the prior art, the present invention has the following advantages and beneficial effects: (1) This invention constructs a magnetic covalent organic framework (COF) material with magnetic separation capability and peroxidase activity using Fe3O4 as the core, and grows gold nanoparticles (Au NPs) and glucose oxidase (GOx) on the surface of Fe3O4@COF to construct a core-shell Fe3O4@COF@Au(GOx) substrate. This substrate can decompose glucose into gluconic acid and hydrogen peroxide, and simultaneously catalyze the oxidation of TMB to ox-TMB, initiating a colorimetric reaction and causing a change in SERS signal intensity, thereby realizing colorimetric-SERS dual-mode detection of glucose.
[0015] (2) The present invention utilizes magnetic COF to construct a substrate material with peroxidase-like catalytic and SERS-enhancing properties, thereby improving the stability of the SERS substrate and the affinity of organic matter. Attached Figure Description
[0016] Figure 1 This is a schematic diagram of the synthesis process of the substrate for the colorimetric-SERS dual-mode detection platform and a schematic diagram of the glucose detection principle in this embodiment of the invention.
[0017] Figure 2These are electron microscope images of the Fe3O4, Fe3O4@COF, Fe3O4@COF@Au and Fe3O4@COF@Au(GOx) substrates in the embodiments of the present invention.
[0018] Figure 3 This is an XRD characterization diagram of the material prepared in the embodiments of the present invention.
[0019] Figure 4 This is a schematic diagram of Fe3O4@COF@Au catalysis and SERS-enhanced detection in an embodiment of the present invention.
[0020] Figure 5 This is the colorimetric glucose detection standard curve in this embodiment of the invention.
[0021] Figure 6 This is the SERS glucose detection standard curve in this embodiment of the invention.
[0022] Figure 7 This is a schematic diagram of the colorimetric and SERS method for selective detection in an embodiment of the present invention. Detailed Implementation
[0023] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of the present application, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present application without creative effort are within the scope of protection of the present application.
[0024] Example 1: like Figure 1 As shown in A, this embodiment provides a method for preparing a glucose detection SERS sensor based on a magnetic covalent organic framework, including the following steps: S1. Gold nanoparticles were prepared by reacting aqueous chloroauric acid solution with sodium citrate solution.
[0025] In one or more preferred embodiments, gold nanoparticles are prepared by the following steps: 50 mL of 0.01 wt% chloroauric acid aqueous solution was heated to boiling with rapid stirring, and then 0.50 mL of 1.0 wt% sodium citrate solution (as a reducing agent) was quickly added to obtain gold nanoparticles.
[0026] S2. Fe3O4 nanoparticles were prepared using FeCl3·6H2O.
[0027] In one or more preferred embodiments, Fe3O4 nanoparticles are prepared by the following steps: FeCl3·6H2O (2.700 g) was dissolved in 50 mL of ethylene glycol. After ultrasonic-assisted dissolution, NaAc (5.750 g) was added, and the mixture was stirred continuously at 700 rpm for 30 minutes on a magnetic stirrer until homogeneous. The mixture was then transferred to a 100 mL high-pressure reactor lined with polytetrafluoroethylene and placed in a vacuum drying oven. The reactor was reacted at 200 °C for 8 hours to obtain the final product.
[0028] FeCl3·6H2O was dissolved in 50 mL of ethylene glycol, and NaAc was added and stirred for 30 minutes. The mixture was then reacted in a polytetrafluoroethylene-lined autoclave at 200°C for 8 hours, and the resulting particle size was 150 nm to 300 nm (around 200 nm).
[0029] S3. Fe3O4 nanoparticles were made into a suspension and reacted with TPAB solution, DMTP solution and acetic acid solution to obtain Fe3O4@COF composite material.
[0030] In one or more preferred embodiments, the Fe3O4@COF composite material is prepared by the following steps: 10.0 mg of Fe3O4 nanoparticles were dispersed in 10 mL of acetonitrile. The Fe3O4 suspension was then mixed with TPAB solution and mechanically stirred at 500 rpm for 10 minutes. DMTP solution was then added, followed by 3-20 mL of 12M acetic acid solution (preferably 400 μL), and the mixture was stirred for 5-30 minutes (preferably 30 minutes). The reaction was allowed to stand for 72 hours. After the reaction, the product was collected by magnetic separation and washed three times alternately with tetrahydrofuran and ethanol to remove unreacted monomers. The resulting dark gray-green Fe3O4@COF composite material was vacuum dried at 60°C and stored for later use.
[0031] S4. The Fe3O4@COF composite material was made into a suspension and reacted with gold nanoparticles and GOx in sequence to obtain Fe3O4@COF@Au(GOx).
[0032] In one or more preferred embodiments, Fe3O4@COF@Au(GOx) is prepared by the following steps: 5.0 mg of Fe3O4@COF composite material was ultrasonically dispersed in an ethanol / water mixed solvent (volume ratio 1:0.5-2, preferably 1:1, 5 mL). 12.0 mL of 30-50 nm (preferably 30 nm) gold nanoparticles (gold nanoparticle seeds) were added to 3 mL of the Fe3O4@COF suspension. After the reaction, Fe3O4@COF@Au was collected by magnetic separation, and the residual reagents were washed three times with ultrapure water. The final product was dispersed in 5 mL of ultrapure water and stored at 4 °C. 100 μL of GOx (2 mg / mL) was mixed with Fe3O4@COF@Au for 30 minutes to obtain Fe3O4@COF@Au(GOx) as a backup sample.
[0033] The structures of the prepared Fe3O4, Fe3O4@COF, Fe3O4@COF@Au, and Fe3O4@COF@Au(GOx) were characterized by transmission electron microscopy (TEM), such as... Figure 2 As shown. By comparing Fe3O4 ( Figure 2 A in (and Fe3O4@COF) Figure 2 The TEM image in section B) shows that the Fe3O4@COF nanoparticles exhibit a distinct core-shell structure, with the diameter increasing from 430±15 nm to 728±80 nm. The outer surface of Fe3O4@COF becomes quite rough and mottled, with the rough parts corresponding to the covalent organic framework layer, which is about 290 nm thick. This indicates that Fe3O4 has been successfully encapsulated by COF nanoflowers. Figure 1 The TEM image of C shows the overall structure of Fe3O4@COF@Au. Uniform and dense distribution of gold nanoparticles can be observed on the surface of the COF nanoflowers. The gold nanoparticles are monodisperse spherical, uniform in size, and approximately 25±6 nm in diameter. TEM image ( Figure 2 D) shows the structure of Fe3O4@COF@Au after immobilization of glucose oxidase (GOx), indicating that the overall structure of Fe3O4@COF@Au did not change after immobilization of GOx.
[0034] The XRD characterization diagrams of the prepared Fe3O4, Fe3O4@COF, Fe3O4@COF@Au, and Fe3O4@COF@Au(GOx) are shown below. Figure 3As shown in Figure A, the diffraction peaks at 2θ values of 30.14°, 35.53°, 43.16°, 57.10°, and 67.76° correspond to the (220), (311), (400), (511), and (440) crystal planes of the Fe3O4 body-centered cubic structure, respectively. In addition, the low-angle peaks at 2θ values of 4.78°, 5.57°, 7.39°, and 9.66° correspond to the (110), (200), (210), and (220) crystal planes of TPAB-DMTPCOF. This confirms the coexistence of the Fe3O4 and COF framework and is consistent with the results of transmission electron microscopy (TEM). After loading gold nanoparticles and glucose oxidase, the diffraction peaks of Fe3O4 and COF nanoflowers in the diffraction pattern of Fe3O4@COF@Au(GOx) decreased, and new peaks appeared at 38.20°, 44.43°, 64.67°, and 77.70°, corresponding to (111), (200), (220), and (311) peaks of face-centered cubic gold. This indicates that the Fe3O4@COF@Au(GOx) sample has extremely high crystallinity, confirming the integrity of the composite material structure.
[0035] The FT-IR spectra of Fe3O4, Fe3O4@COF, Fe3O4@COF@Au, and Fe3O4@COF@Au(GOx) are as follows: Figure 3 As shown in B, for bare Fe3O4, the characteristic Fe-O-Fe vibrational peak at approximately 550 cm⁻¹, along with the C=O stretching vibration (1384 cm⁻¹) and CO antisymmetric vibration (1593 cm⁻¹) of the surface carboxyl groups, confirms the successful preparation of Fe3O4. After COF growth, the spectrum of Fe3O4@COF retains all the peaks of Fe3O4, while a new sharp peak appears at 1615 cm⁻¹, corresponding to the -C=N stretching vibration of the imine bond formed through the Schiff base reaction between TPAB and DMTP monomers. The spectral peak generated at 1650 cm⁻¹ is due to the C=O stretching vibration of GOx. This result indicates the presence of GOx in the Fe3O4@COF@Au(GOx) composite material.
[0036] The magnetic properties of Fe3O4, Fe3O4@COF, Fe3O4@COF@Au, and Fe3O4@COF@Au(GOx) are demonstrated by the hysteresis loop ( Figure 3 Quantitative analysis was performed on Fe3O4, Fe3O4@COF, and Fe3O4@COF@Au(GOx). The magnetic saturation values (MS) of Fe3O4, Fe3O4@COF, and Fe3O4@COF@Au(GOx) were approximately 57, 32, and 22 emu / g, respectively. The decrease in MS values indicates that the loading of gold nanoparticles and GOx weakens the magnetism as COF grows. Despite the weakening of magnetism, it still possesses good magnetic properties and can achieve rapid separation. Figure 3 (D in the middle).
[0037] Example 2: This embodiment provides a glucose detection SERS sensor based on a magnetic covalent organic framework, with the chemical formula Fe3O4@COF@Au(GOx), which can be prepared by the preparation method described in Example 1.
[0038] Example 3: This embodiment provides a colorimetric-SERS dual-mode glucose detection method, applying a glucose detection SERS sensor based on a magnetic covalent organic framework as described in Embodiment 2, specifically including the following steps: For glucose detection, 50-200 µL of Fe3O4@COF@AuNPs(GOx) substrate (prepared by the method described in Example 1) was placed in a centrifuge tube. 100-200 µL of TMB colorimetric solution (5 mM), 1 mL of NaAc-HAc buffer solution (pH=4), and 200 µL of glucose standard solution were added sequentially. The mixture was reacted at the optimal temperature for 25 min (or at 40°C for 15 min). Immediately after reaction, the absorbance at 655 nm was measured using a UV-Vis spectrophotometer, and the Raman signal was simultaneously acquired using a 785 nm laser Raman spectrometer. Raman spectroscopy testing and analysis can be performed by dropping the sample onto a 96-well plate.
[0039] The feasibility of this detection method is analyzed through the following steps: (1) The catalytic and SERS-enhancing performance of AuNPs, COF, Fe3O4, Fe3O4@COF, and Fe3O4@COF@Au were evaluated using a colorimetric reaction catalyzed by H2O2-TMB on Fe3O4@COF@Au substrates. Specifically, the nanozyme solution was mixed with a solution containing 200 µL of TMB solution (5 mM), 1 mL of NaAc-HAc buffer (pH 4.0), and 200 µL of H2O2 (1 mM). The mixture was incubated at 37°C for 30 minutes, and the color change was observed. SERS was detected using a Raman spectrometer with an excitation wavelength of 785 nm. The test results are as follows: Figure 4 As shown, Fe3O4@COF@Au exhibits both excellent catalase activity and excellent SERS enhancement performance.
[0040] like Figure 4 As shown in Figure A, it can be observed that after adding Fe3O4@COF@Au as a catalyst to the TMB-H2O2 system, a significant absorption peak for TMB oxidation appeared at 655 nm, indicating that it has peroxidase-like properties. Figure 4As shown in B, it can be observed that the catalytic effect of Fe3O4@COF@Au is not obvious after the addition of glucose, while Fe3O4@COF@Au(GOx) can show a significant TMB oxidation absorption peak at 655 nm, which indicates that Fe3O4@COF@Au(GOx) has tandem enzyme activity. Figure 4 The C in the figure shows the SERS signal of ox-TMB generated by different substrates and its SERS signal was measured using the corresponding substrate. Figure 4 D in the figure shows the SERS signal intensity measured by CV at different concentrations using Fe3O4@COF@Au as the substrate material, expressed by the formula EF=(I SERS / C SERS ) / (I Raman / C Raman The enhancement factor was estimated. The results show that, based on 1175 cm⁻¹, -1 The estimated EF from the band Raman intensity can reach 1.45 × 10^ 6 .
[0041] (2) Replace the H2O2 solution in step (1) with glucose, and use the Fe3O4@COF@Au(GOx) substrate for colorimetric-SERS dual-mode detection of glucose to verify the tandem enzyme activity and SERS enhancement effect. The colorimetric test results are as follows: Figure 5 As shown, the colorimetric method exhibits excellent linearity in the concentration range of 1-500 µM. The SERS detection method test results are as follows: Figure 6 As shown, the detection concentration range exhibits excellent linearity within 50 nM-500 µM, proving that Fe3O4@COF@Au(GOx) retains both tandem enzyme activity and can achieve SERS detection.
[0042] The sensitivity of the contrast-mode sensor was analyzed under optimal experimental conditions. For example... Figure 5 As shown in Figure A, the solution color gradually changes from colorless to blue as the glucose concentration increases from 1 to 500 µM. The characteristic absorption peak of ox-TMB at 655 nm is observed. Figure 5 Further analysis (B) showed that there was a good linear relationship between the absorbance at 655 nm and the logarithm of glucose concentration (1-500 µM), with a correlation coefficient of 0.995 for the linear fitting equation and a detection limit of 0.17 µM for the colorimetric method.
[0043] Figure 6 This is the SERS standard curve for glucose detection in this embodiment of the invention. The SERS detection results are consistent with the colorimetric detection results, and the Raman spectrum is as follows. Figure 6 As shown in A, oxidized TMB increases with increasing glucose concentration at 1316 cm⁻¹. -11381cm -1 and 1593cm -1 The characteristic peak intensity increases at 1593 cm⁻¹. For oxidized TMB, this is at 1593 cm⁻¹. -1 Raman Peak at the location of Raman Peak ( Figure 6 Further analysis of B) in the study showed that, within the concentration range of 50 nM to 500 µM, I 1593 The Raman peak intensity is linearly related to glucose concentration, and the detection limit for glucose can reach 10.7 nM.
[0044] (4) Figure 7 In the figure, A and B represent the absorbance at 655 nm and I, measured under the same conditions based on Fe3O4@COF@Au(GOx), after the addition of glucose and other different molecular weights of fructose, maltose, lactose, sucrose, and glucose. 1592 / I 866 The change in the ratio indicates that the prepared substrate has excellent selectivity.
[0045] It should be understood that various parts of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented using software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.
[0046] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.
Claims
1. A method for fabricating a glucose detection SERS sensor based on a magnetic covalent organic framework, characterized in that, Includes the following steps: Preparation of gold nanoparticles and Fe3O4 nanoparticles; Fe3O4 nanoparticles were prepared into a suspension and reacted with TPAB solution, DMTP solution and acetic acid solution to obtain Fe3O4@COF composite material; Fe3O4@COF composite material was prepared into a suspension and reacted sequentially with gold nanoparticles and GOx to obtain Fe3O4@COF@Au(GOx).
2. The method for preparing a glucose detection SERS sensor based on a magnetic covalent organic framework according to claim 1, characterized in that, Gold nanoparticles were prepared by reacting an aqueous solution of chloroauric acid with a sodium citrate solution, specifically as follows: 50 mL of 0.01 wt% chloroauric acid aqueous solution was heated to boiling with stirring, and 0.50 mL of 1.0 wt% sodium citrate solution was immediately added as a reducing agent to obtain gold nanoparticles.
3. The method for preparing a glucose detection SERS sensor based on a magnetic covalent organic framework according to claim 1, characterized in that, Fe3O4 nanoparticles were prepared using FeCl3·6H2O, specifically as follows: FeCl3·6H2O was dissolved in 50 mL of ethylene glycol, NaAc was added and stirred for 30 minutes, and then reacted in a polytetrafluoroethylene-lined autoclave at 200°C for 8 hours to obtain Fe3O4 nanoparticles with a particle size of 150 nm to 300 nm.
4. The method for preparing a glucose detection SERS sensor based on a magnetic covalent organic framework according to claim 1, characterized in that, The process of preparing Fe3O4 nanoparticles into a suspension and reacting them with TPAB solution, DMTP solution, and acetic acid solution to obtain Fe3O4@COF composite material is as follows: The synthesized Fe3O4 nanoparticles were ultrasonically dispersed in acetonitrile, and TPAB and DMTP were dissolved in 10 mL of acetonitrile to prepare Fe3O4 suspensions. After mixing the Fe3O4 suspension with TPAB and DMTP solutions under mechanical stirring at 300-1000 rpm for 5-30 minutes, add 3-20 mL of 12M acetic acid solution and let the reaction stand for 72 hours. The resulting Fe3O4@COF composite material is then vacuum dried at 60 degrees Celsius and stored for later use.
5. The method for preparing a glucose detection SERS sensor based on a magnetic covalent organic framework according to claim 1, characterized in that, The process of preparing the Fe3O4@COF composite material into a suspension and reacting it sequentially with gold nanoparticles and GOx is as follows: 5.0 mg of Fe3O4@COF composite material was ultrasonically dispersed in 5 mL of a mixed solvent of ethanol / water with a volume ratio of 1:0.5-2. Add 30-50 nm gold nanoparticles to the Fe3O4@COF suspension; after the reaction is complete, collect Fe3O4@COF@Au by magnetic separation, and then wash the residual reagents three times with ultrapure water; Fe3O4@COF@Au was dispersed in 5 mL of ultrapure water; Mix 100 μL of GOx at a concentration of 1-4 mg / mL with Fe3O4@COF@Au and react for 10-40 minutes to obtain Fe3O4@COF@Au(GOx) as a spare sample.
6. A glucose detection SERS sensor based on a magnetic covalent organic framework, characterized in that, The chemical formula is Fe3O4@COF@Au(GOx), and it is prepared by the preparation method according to any one of claims 1-5.
7. A colorimetric-SERS dual-mode glucose detection method, characterized in that, Includes the following steps: The SERS sensor for glucose detection based on a magnetic covalent organic framework as described in claim 6 was placed in a centrifuge tube, and a colorimetric solution, a buffer solution, and a glucose solution to be tested were added to the centrifuge tube in sequence to carry out the reaction. Immediately after the reaction, the absorbance at 655 nm was measured using a UV-Vis spectrophotometer, and the Raman signal was simultaneously acquired using a 785 nm laser Raman spectrometer to plot the working curve.
8. The method for detecting glucose using a colorimetric-SERS dual-mode assay according to claim 7, characterized in that, The volume of the glucose detection SERS sensor based on the magnetic covalent organic framework added was 50-200 µL, the colorimetric solution added was 100-200 µL of TMB colorimetric solution, the buffer solution added was 1 mL of NaAc-HAc buffer solution with pH=4, the volume of the glucose solution to be tested added was 200 µL, and the reaction time was 25 min.