Molecularly imprinted gold aerogel induced by polydopamine as well as preparation method and application of molecularly imprinted gold aerogel

Abstract

The invention relates to polydopamine-induced molecularly imprinted gold aerogel as well as a preparation method and application thereof. The preparation method comprises the following steps: mixing dopamine with template molecules, and stirring under an alkaline condition to form a molecularly imprinted polymer solution taking polydopamine as a functional monomer; adding the prepared molecularly imprinted polymer solution into a gold nanoparticle solution, and stirring to initiate self-assembly of gold nanoparticles to form gold hydrogel; and eluting the gold hydrogel to remove template molecules, and freeze-drying to obtain the molecularly imprinted gold aerogel. The molecularly imprinted gold aerogel can be used as a substrate of a surface enhanced Raman scattering sensor and is used for enrichment detection of an object to be detected. Compared with the prior art, the molecularly imprinted gold aerogel disclosed by the invention can be used for improving high-selectivity recognition on specific pollutants so as to enhance SERS (Surface Enhanced Raman Scattering) signals in a surface enhanced Raman scattering spectrum test.

Description

Technical Field

[0001] The invention belongs to the technical field of aerogel preparation, and in particular relates to the preparation and application of polydopamine-induced molecularly imprinted gold aerogel. Background Art

[0002] Surface-enhanced Raman spectroscopy (SERS) is an analytical technique that characterizes substances adsorbed on rough precious metal surfaces at the molecular level. By adsorbing molecules onto the surface of rough metal or metal sol particles, an enhanced signal compared to conventional Raman scattering can be obtained. This technique requires no labeling and offers high sensitivity and accuracy. The SERS enhancement effect depends primarily on the size, morphology, and uniformity of the metal nanostructures.

[0003] CN110907425A discloses a surface molecular imprinting SERS sensor based on core-shell structured polydopamine-coated gold nanoparticles. Dopamine is used as a functional monomer and phthalates are used as template molecules. Self-polymerization occurs on the surface of gold nanoparticles to obtain molecular imprinting polymers, which are then eluted and drop-coated on the surface of a screen-printed electrode to obtain a surface molecular imprinting SERS sensor.

[0004] However, in actual surface-enhanced Raman spectroscopy testing, the above-mentioned surface molecular imprinting SERS sensor needs to be combined with electrochemical enrichment technology to achieve the purpose of selectively enriching the analyte and enhancing the SERS signal. The operation is cumbersome and limits the selective identification of specific environmental pollutants in surface-enhanced Raman spectroscopy testing. Summary of the Invention

[0005] The purpose of the present invention is to provide a polydopamine-induced molecularly imprinted gold aerogel, a preparation method and an application thereof in order to overcome the defect in the existing SERS test that requires the combination with electrochemical enrichment technology to selectively identify specific compounds.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] The present invention first provides a method for preparing polydopamine-induced molecularly imprinted gold aerogel, the preparation method comprising the following steps:

[0008] S1: dopamine and template molecule are mixed in a molar ratio of (4-16):1 and stirred under alkaline conditions to form a molecularly imprinted polymer solution with polydopamine as the functional monomer;

[0009] S2: adding the molecularly imprinted polymer solution prepared in S1 to the gold nanoparticle solution and stirring to induce the self-assembly of the gold nanoparticles to form a gold hydrogel;

[0010] S3: eluting the gold hydrogel to remove the template molecules, and freeze-drying to obtain the molecularly imprinted gold aerogel.

[0011] Furthermore, in step S1, the stirring temperature is 50-60°C.

[0012] Furthermore, in step S1, the stirring time is 3-5 hours.

[0013] Furthermore, in step S1, the stirring speed is 300-500 rpm.

[0014] Furthermore, in step S1, the pH under the alkaline condition is 8-9.

[0015] Furthermore, the reaction is carried out in a Tris-HCl solution (pH=8.5).

[0016] Furthermore, in step S2, the ratio of the molar amount of the template molecule in the molecularly imprinted polymer to the molar amount of the gold element in the gold nanoparticles is 4:(18-25), preferably 4:21.

[0017] Furthermore, in step S2, the gold nanoparticle solution is prepared by stirring dehydrated trisodium citric acid and gold chloride trihydrate in water until uniformly mixed, and then adding sodium borohydride and stirring to form a gold nanoparticle solution.

[0018] Furthermore, the molar ratio of the dehydrated trisodium citric acid, gold chloride trihydrate and sodium borohydride is preferably 200:21:8.

[0019] Furthermore, the stirring time for both times is 15-30 minutes.

[0020] Furthermore, in step S2, the particle size of the gold nanoparticles is in the range of 15-25 nm.

[0021] Furthermore, in step S2, the self-assembly time is 6-10 hours.

[0022] Furthermore, in step S2, the self-assembly is performed at room temperature.

[0023] Furthermore, in step S3, the eluent used for elution is an alcohol solution.

[0024] Furthermore, the eluent is an ethanol-water solution, and the volume ratio of ethanol to water in the eluent is 1:(4-5).

[0025] Furthermore, in step S3, elution is performed at least 3 times, with each elution time being 1-3 hours.

[0026] The present invention also provides a molecularly imprinted gold aerogel produced using the aforementioned preparation method. Three-dimensional porous metal nanostructures exhibit significant advantages in catalysis, sensing, and energy storage due to their unique collective electronic effects, high specific surface area, and tunable pore properties. Metal aerogels, a typical example of this type, are lightweight materials with high porosity, low density, and high specific surface area, and have great potential for application in surface-enhanced Raman spectroscopy.

[0027] Furthermore, the molecularly imprinted gold aerogel has a microporous structure with a pore size ranging from 1 to 1.6 nm and uniform distribution.

[0028] Furthermore, the specific surface area of ​​the molecularly imprinted gold aerogel is 30-40m 2 / g.

[0029] The present invention also provides an application of a molecularly imprinted gold aerogel in surface-enhanced Raman scattering spectroscopy testing. The molecularly imprinted gold aerogel is used as a substrate of a surface-enhanced Raman scattering sensor for enrichment detection of an analyte.

[0030] Furthermore, the enrichment detection step is: immersing the molecularly imprinted gold aerogel in a solution containing the analyte, enriching for 200-400 seconds, taking it out and drying it, and then performing surface enhanced Raman scattering spectroscopy testing.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] (1) The present invention combines gold aerogel with molecular imprinting technology to successfully prepare molecularly imprinted gold aerogel induced by polydopamine. The polydopamine in the aerogel can act as a functional monomer, which can further enhance the highly selective identification of specific trace pollutants in the environment. In surface-enhanced Raman scattering spectroscopy testing, the SERS signal of specific pollutants can be enhanced without the need to combine it with other technologies such as electrochemical enrichment technology, thereby simplifying the operation and improving the detection efficiency.

[0033] (2) The present invention combines molecular imprinting technology with gold aerogel to construct specific recognition sites for specific pollutants (such as phenolic compounds) on the aerogel surface, significantly improving the anti-interference ability of the detection system. The polydopamine of the present invention is used as a functional monomer. The multiple interactions (hydrogen bonds, coordination bonds, π-π stacking) formed between the catechol groups in its molecular structure and the template molecules can significantly improve the adsorption selectivity of the aerogel for target pollutants. It only needs to immerse the molecularly imprinted gold aerogel in the solution to be tested to automatically enrich specific pollutants. It is suitable for trace pollutants (concentrations as low as 10 -10 M) accurate identification and detection.

[0034] (3) The gold aerogel prepared by the present invention has a fluffy porous structure and a large specific surface area, and the polydopamine of the present invention can act as a "bridge" and "adhesive" between the nanostructures of the gold aerogel, connecting the nanoparticles or nanoskeleton of the gold aerogel more tightly, thereby enhancing the overall mechanical strength and stability of the gold aerogel, making it less likely to suffer structural damage and deformation when subjected to external forces.

[0035] (4) The polydopamine in the present invention is used as an initiator, which has the advantages of being safe and environmentally friendly, readily available and inexpensive, having mild polymerization reaction conditions, and not requiring an additional cross-linking agent.

[0036] (5) The introduction of the molecular imprinting layer of the present invention does not affect the original high specific surface area and mechanical strength of the aerogel, and the imprinting sites after eluting the template molecules have good reusability. After multiple cycles of use, the SERS signal intensity retention rate is still higher than 90%, which significantly reduces the detection cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is the ultraviolet absorption spectrum of the gold nanoparticles prepared in Example 1.

[0038] Figure 2 This is a physical photo of the molecularly imprinted gold aerogel prepared in Example 1.

[0039] Figure 3 This is the SEM image of the molecularly imprinted gold aerogel prepared in Example 1.

[0040] Figure 4 This is the X-ray diffraction spectrum of the molecularly imprinted gold aerogel prepared in Example 1.

[0041] Figure 5 This is the XPS spectrum of the molecularly imprinted gold aerogel prepared in Example 1.

[0042] Figure 6 This is the SEM image of the molecularly imprinted gold aerogel prepared in Comparative Example 4.

[0043] Figure 7 The SERS signal spectrum of the molecularly imprinted gold aerogel in Example 1 at different concentrations of bisphenol A.

[0044] Figure 8 These are the SERS signal spectra obtained for the gold aerogels of Example 1 and Comparative Example 5, as well as those without any substrate.

[0045] Figure 9 The SERS signal spectrum of the molecularly imprinted gold aerogel of Example 8 at different concentrations of 4-nitrophenol DETAILED DESCRIPTION

[0046] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0047] Unless otherwise specified, the reagents, methods, instruments and equipment used in the present invention are conventional reagents, methods, instruments and equipment in the art. Unless otherwise specified, the reagents and materials used in the following examples are commercially available.

[0048] Example 1:

[0049] This embodiment provides a polydopamine-induced molecularly imprinted gold aerogel, and the specific preparation method is as follows:

[0050] (1) 250 μL of a 0.4 mol / L dehydrated trisodium citric acid aqueous solution and 300 μL of 0.035 mol / L gold chloride trihydrate were added sequentially to a clean 50 mL beaker containing 40 mL of deionized water and stirred for approximately 15 minutes. Then, 200 μL of a 0.02 mol / L freshly prepared sodium borohydride aqueous solution was quickly added, and stirring was continued for approximately 15 minutes to form a gold nanoparticle solution.

[0051] In this step, the UV absorption spectrum of the gold nanoparticles prepared is as follows: Figure 1 As shown, the wavelength of the peak of the visible ultraviolet absorption spectrum is 520 nm, indicating that the particle size of the gold nanoparticles is about 20 nm, which illustrates the successful preparation of the gold nanoparticle solution, compared with smaller particles (such as <10 nm, easy to agglomerate) or larger particles (such as >50 nm, easy to sediment).

[0052] (2) 80 μL of 0.3 mol / L dopamine aqueous solution and 40 μL of 0.05 mol / L bisphenol A (template molecule) aqueous solution were added to 2 mL of Tris-HCl solution (pH = 8.5) and stirred at 50 °C for 4 h to form a molecularly imprinted polymer (MIP-PDA) solution with polydopamine as the functional monomer.

[0053] (3) After ultrasonicating the synthesized gold nanoparticle solution for 0.5 h, the prepared MIP-PDA solution was added to the gold nanoparticle solution, stirred for 15 minutes, and then allowed to stand at room temperature. After 8 h of self-assembly, black gold hydrogel was precipitated at the bottom of the container.

[0054] (4) The gold hydrogel was washed three times with an ethanol-water solution, each washing time being 3 hours, wherein the volume ratio of ethanol to deionized water was 1:4. After washing, the hydrogel was placed in a freezer for 3 hours and then placed in a vacuum freeze drying oven at -40°C for 4 hours to obtain the molecularly imprinted gold aerogel of this embodiment.

[0055] The actual photo of the molecularly imprinted gold aerogel prepared in this example is shown in the figure. Figure 2 As shown, the appearance is black. After polydopamine-induced assembly, the wet gel formed is a black flocculent precipitate. After freeze-drying, it still remains black and has a light texture. Molecularly imprinted gold aerogel is a porous and fluffy solid structure, similar to sponge or foam, with extremely low density and high specific surface area. The specific surface area of ​​the molecularly imprinted gold aerogel prepared in this example is 35.1m 2 / g.

[0056] The SEM image of the molecularly imprinted gold aerogel prepared in this example is as follows: Figure 3 Scanning electron microscopy (SEM) observations show that the molecularly imprinted gold aerogel consists of a network of interconnected nanowires. The nanowire diameters are consistent with the original gold nanoparticles, indicating that the structure is formed by direct fusion of the nanoparticles. The aerogel also exhibits a porous, fluffy solid structure. The molecularly imprinted gold aerogel has a uniformly distributed microporous structure with a maximum pore size of approximately 1.6 nm.

[0057] The X-ray diffraction (XRD) spectrum of the molecularly imprinted gold aerogel prepared in this example is as follows: Figure 4 The results show that the nanowires are a face-centered cubic (fcc) polycrystalline gold structure, and the diffraction peaks correspond to crystal planes such as (111) and (200), confirming their metallic gold crystal structure.

[0058] The XPS wide scan (A), Au 4f (B), N 1s (C) and C1s (D) spectra of the molecularly imprinted gold aerogel prepared in this example are shown in Figure 2. Figure 5 As shown. (B) The peak centers in the spectrum are 84.0eV and 87.7eV, which are consistent with the standard binding energy of metallic gold. There is no obvious chemical shift and no oxidation state characteristics (such as binding energy shift), indicating that Au in the sample exists mainly in the form of metal element. (C) The peak center of the spectrum is approximately 399eV, while the chemical environment of N in polydopamine is mainly pyrrole-type N (pyrrole ring, ~398.5eV) and imine-type N (C=N, ~399.5eV), both of which fall in the range of 398-401eV. In addition, the main peak of the spectrum in (D) is concentrated at ~284.5eV, corresponding to the aromatic ring C=C, proving that polydopamine is successfully composited in molecularly imprinted gold aerogel.

[0059] Example 2:

[0060] This embodiment provides a polydopamine-induced molecularly imprinted gold aerogel. Compared with Example 1, most of the features are the same, except that in step (1), the concentration of the dehydrated trisodium citric acid aqueous solution added is 0.3 mol / L.

[0061] Example 3:

[0062] This embodiment provides a polydopamine-induced molecularly imprinted gold aerogel. Compared with Example 1, most of the features are the same, except that in step (1), the concentration of the dehydrated trisodium citric acid aqueous solution added is 0.5 mol / L.

[0063] Example 4:

[0064] This embodiment provides a polydopamine-induced molecularly imprinted gold aerogel. Compared with Example 1, most of the features are the same, except that in step (2), the concentration of the added dopamine solution is 0.1 mol / L.

[0065] Example 5:

[0066] This embodiment provides a polydopamine-induced molecularly imprinted gold aerogel. Compared with Example 1, most of the features are the same, except that in step (2), the concentration of the added dopamine solution is 0.2 mol / L.

[0067] Example 6:

[0068] This embodiment provides a polydopamine-induced molecularly imprinted gold aerogel. Compared with Example 1, most of the features are the same, except that in step (2), the concentration of the added dopamine solution is 0.4 mol / L.

[0069] Example 7:

[0070] This embodiment provides a polydopamine-induced molecularly imprinted gold aerogel. Compared with Example 1, most of the steps are the same, except that in step (2), bisphenol A is replaced by 4-nitrophenol, that is, the template molecule of this embodiment is 4-nitrophenol.

[0071] Comparative Example 1:

[0072] This comparative example is similar to Example 1 in most respects, except that, in step (1), no dehydrated trisodium citric acid aqueous solution is added.

[0073] When not adding dehydrated trisodium citric acid aqueous solution, in the step of preparing gold nanoparticle solution, the stability of solution system is greatly affected. In the preparation process of embodiment 1, dehydrated trisodium citric acid is used as a stabilizer, which not only can prevent the reunion of gold nanoparticles, but also participates in the formation process of gold nanoparticles, controlling its growth rate and particle size. And in Comparative Example 1, lacking dehydrated trisodium citric acid, gold chloride trihydrate, when reacting with sodium borohydride, the formation of gold nanoparticles becomes uncontrollable. During stirring, it can be obviously observed that the solution color changes abnormally, the gold nanoparticles generated by the reaction rapidly reunite, and turbidity phenomenon occurs in the solution very soon, and it is impossible to form a uniformly dispersed gold nanoparticle solution.

[0074] Comparative Example 2:

[0075] This comparative example is similar to Example 1 in most respects, except that in step (1), the dehydrated trisodium citric acid aqueous solution is replaced with a 5-mercaptomethyltetrazole aqueous solution.

[0076] 5-Mercaptomethyltetrazole has a strong coordination ability and is a strong stabilizer. Both the thiol group and the nitrogen atom in its molecule can coordinate with metal ions. When a 5-mercaptomethyltetrazole aqueous solution is used instead of dehydrated trisodium citric acid, during the preparation of the gold nanoparticle solution, 5-mercaptomethyltetrazole quickly coordinates with the gold ions, and the color of the solution changes very quickly to a dark brown color. Furthermore, it is unable to form a gel in the subsequent step (2).

[0077] Comparative Example 3:

[0078] This comparative example is similar to Example 1 in most respects, except that no dopamine solution is added in step (2). It was found that the successful preparation of a three-dimensional hydrogel network could not be achieved.

[0079] The polydopamine in the present invention can induce gold nanoparticles, such as citrate-stabilized gold nanoparticles, to form a three-dimensional hydrogel network. Citrate stabilizes the gold nanoparticles through electrostatic interactions and steric hindrance, while polydopamine competes with citrate for adsorption on the surface of the gold nanoparticles, weakening their stability and promoting the aggregation of the nanoparticles to form a three-dimensional network structure.

[0080] Comparative Example 4:

[0081] This comparative example is similar to Example 1 in most respects, except that in step (2), the concentration of the dopamine solution added is 0.5 mol / L.

[0082] The SEM characterization of the molecularly imprinted gold aerogel prepared in this comparative example is as follows: Figure 6 As shown, the addition of excessive dopamine in this comparative example unexpectedly resulted in a denser, darker, and more fuzzy three-dimensional network structure, a reduced number of pores, poor connectivity, and the appearance of localized "agglomerates" or structural collapse. In contrast, the molecularly imprinted gold aerogel produced in the present invention at a reasonable dopamine concentration exhibited a fluffy three-dimensional network structure with abundant pores and good connectivity.

[0083] Comparative Example 5:

[0084] This comparative example is similar to Example 1 in most respects, except that in step (2), no bisphenol A solution is added, that is, the gold aerogel in this comparative example cannot specifically recognize bisphenol A.

[0085] In order to further verify the application of the molecularly imprinted gold aerogel of the present invention in surface-enhanced Raman scattering spectroscopy testing, the gold aerogel prepared above was used as the substrate of a surface-enhanced Raman scattering sensor to perform enrichment detection of the analyte, and the steps were as follows:

[0086] (1) Preparation of template molecule solution: Taking bisphenol A as an example, a set of template molecule solutions containing different concentrations (1.0×10 -12 -1.0×10 -4 mol·L -1 ) of bisphenol A standard aqueous solution, and blank standard sample.

[0087] (2) The prepared gold aerogels were immersed in solutions containing different concentrations of bisphenol A for 300 seconds. They were then taken out and dried for SERS detection, where good SERS signals were detected with a Raman excitation wavelength of 785 nm, an integration time of 20 seconds, and an integrated intensity of 20.

[0088] The results show that:

[0089] The SERS signal spectra of the molecularly imprinted gold aerogel of Example 1 at different concentrations of bisphenol A are as follows: Figure 7 As shown in Figure 2, the SERS signal increases with the increase of bisphenol A concentration, and the molecularly imprinted gold aerogel of Example 1 can detect concentrations as low as 10 -10 M of bisphenol A. Specifically, BPA at 821 cm -1 The Raman peak nearby is the out-of-plane bending vibration of the benzene ring (the characteristic peak of para-disubstituted benzene, reflecting the two hydroxyl groups in the para position). This peak is one of the key peaks for identifying the structure of bisphenol A; 1176 cm -1 The Raman peak nearby is the CO stretching vibration (CO bond of phenolic hydroxyl group). This peak is also a characteristic peak; 1605cm -1 The nearby Raman peak is the C=C stretching vibration (ring breathing mode) of the benzene ring, which is the strongest peak.

[0090] The concentration was 1.0×10 -5 mol / L bisphenol A was used as the test concentration, and the SERS spectra of the gold aerogels of Example 1 and Comparative Example 5 and those obtained without any substrate were further measured. Figure 8 As shown, the enhanced Raman effect of the molecularly imprinted gold aerogel prepared in Example 1 as a substrate is significantly better than that of the gold aerogel without adding template molecules, indicating that the molecularly imprinted gold aerogel of the present invention significantly improves the specific recognition of the test substance in the surface enhanced Raman scattering spectroscopy test.

[0091] In order to verify the universal application effect of the molecularly imprinted gold aerogel of the present invention, Figure 9The SERS signal spectra of the molecularly imprinted gold aerogel of Example 8 at different concentrations of 4-nitrophenol are shown. As shown in the figure, 4-nitrophenol has a peak at 1337 cm -1 The Raman peak near 1595cm corresponds to the symmetrical stretching of the NO bond, which is the characteristic peak of the nitro group; -1 The Raman peaks nearby correspond to the stretching vibration of the C=C double bond of the benzene ring. The above results indicate that the molecularly imprinted gold aerogel of the present invention can also enhance the SERS signals of analytes corresponding to other template molecules in surface enhanced Raman scattering spectroscopy tests.

[0092] In summary, the present invention combines gold aerogel with molecular imprinting technology to successfully produce molecularly imprinted gold aerogel induced by polydopamine, in which polydopamine can act as a functional monomer, which can further enhance the highly selective recognition of specific trace pollutants in the environment, thereby enhancing the SERS signal in surface-enhanced Raman scattering spectroscopy testing. By combining molecular imprinting technology with gold aerogel, the present invention can construct specific recognition sites for specific pollutants (such as phenolic compounds) on the aerogel surface without the need for electrochemical enrichment technology, significantly improving the anti-interference ability of the detection system and the adsorption selectivity of the target pollutants, and is suitable for the accurate identification and detection of trace pollutants in complex environmental samples (such as water and soil leachate).

[0093] The above description of the embodiments is intended to facilitate understanding and use of the invention by those skilled in the art. It will be apparent that those skilled in the art can readily make various modifications to these embodiments and apply the general principles described herein to other embodiments without requiring inventive effort. Therefore, the present invention is not limited to the above-described embodiments. Improvements and modifications made by those skilled in the art based on the disclosure of the present invention, without departing from the scope of the present invention, should be within the scope of protection of the present invention.

Claims

1. A method for preparing polydopamine-induced molecularly imprinted gold aerogel, characterized in that: The preparation method comprises the following steps: S1: dopamine and template molecule are mixed in a molar ratio of (4-16):1 and stirred under alkaline conditions to form a molecularly imprinted polymer solution with polydopamine as the functional monomer; S2: adding the molecularly imprinted polymer solution prepared in S1 to the gold nanoparticle solution and stirring to induce the self-assembly of the gold nanoparticles to form a gold hydrogel; S3: eluting the gold hydrogel to remove the template molecules, and freeze-drying to obtain the molecularly imprinted gold aerogel.

2. The method for preparing a polydopamine-induced molecularly imprinted gold aerogel according to claim 1, characterized in that: In step S1, the stirring temperature is 50-60°C, the stirring time is 3-5 hours, and the stirring speed is 300-500 rpm.

3. The method for preparing a polydopamine-induced molecularly imprinted gold aerogel according to claim 1, characterized in that: In step S1, the pH under the alkaline condition is 8-9.

4. The method for preparing a polydopamine-induced molecularly imprinted gold aerogel according to claim 1, characterized in that: In step S2, the ratio of the molar amount of the template molecule in the molecularly imprinted polymer to the molar amount of the gold element in the gold nanoparticles is 4:(18-25).

5. The method for preparing a polydopamine-induced molecularly imprinted gold aerogel according to claim 1, characterized in that: In step S2, the preparation method of the gold nanoparticle solution is: Dehydrated trisodium citric acid and gold chloride trihydrate were stirred and mixed uniformly in water, and then sodium borohydride was added and stirred to form a gold nanoparticle solution; The molar ratio of the dehydrated trisodium citric acid, gold chloride trihydrate and sodium borohydride is 200:21:

8.

6. The method for preparing a polydopamine-induced molecularly imprinted gold aerogel according to claim 1, characterized in that: In step S2, the particle size of the gold nanoparticles is in the range of 15-25 nm.

7. The method for preparing a polydopamine-induced molecularly imprinted gold aerogel according to claim 1, characterized in that: In step S2, the self-assembly time is 6-10 hours, and the self-assembly is performed at room temperature.

8. The method for preparing polydopamine-induced molecularly imprinted gold aerogel according to claim 1, characterized in that: In step S3, the elution liquid used is an alcohol solution, and the elution is performed at least 3 times, with each elution time being 1-3 hours.

9. A molecularly imprinted gold aerogel prepared by the preparation method according to any one of claims 1 to 9, characterized in that: The molecularly imprinted gold aerogel has a microporous structure with a pore size range of 1-1.6 nm and uniform distribution; the specific surface area of ​​the molecularly imprinted gold aerogel is 30-40 m 2 / g.

10. Use of the molecularly imprinted gold aerogel according to claim 9 in surface enhanced Raman scattering spectroscopy testing, characterized in that: The molecularly imprinted gold aerogel is used as a substrate for a surface-enhanced Raman scattering sensor for enrichment detection of an analyte; The enrichment detection step is: immersing the molecularly imprinted gold aerogel in a solution containing the analyte, enriching for 200-400 seconds, taking it out and drying it, and then performing surface enhanced Raman scattering spectroscopy testing.

Images