Preparation method and application of Au@AgNPs-Van / PDMS thin film SERS detection platform

Abstract

The invention discloses a preparation method and application of an Au@AgNPs-Van / PDMS thin film SERS detection platform. First, an Au@AgNPs sol is prepared, then an Au@AgNPs-Van solution is synthesized, and finally an Au@AgNPs-Van / PDMS thin film SERS detection platform is constructed: a PDMS film is subjected to a hydrophilic treatment, the hydrophilic treated PDMS film is placed in 3-aminopropyl-trimethoxysilane, shaken and cultured overnight, washed with water and placed in an Au@AgNPs-Van solution, and reacted and taken out to obtain an Au@Ag NPs-Van / PDMS film. The invention realizes the application of the Au@AgNPs-Van / PDMS thin film SERS detection platform to the rapid capture, enrichment and SERS detection of foodborne pathogens in actual beef samples, and realizes the rapid capture, enrichment and detection of foodborne pathogens in a complex solution environment.

Description

Technical Field

[0001] The invention belongs to the technical field of foodborne pathogenic bacteria detection, and specifically relates to a preparation method and application of an Au@AgNPs-Van / PDMS film SERS detection platform. Background Art

[0002] Surface-enhanced Raman Scattering (SERS) is a highly sensitive, rapid, non-destructive spectral technology. Due to its ultra-high sensitivity and fingerprint recognition ability, it has become an ideal choice for foodborne pathogen analysis. It overcomes the disadvantage of weak Raman spectroscopy signals and can directly obtain the fingerprint of the target substance.

[0003] At present, the commonly used enhancement substrate is mainly noble metal sol, but noble metal sol has great limitations in the qualitative and quantitative process. Ordinary SERS substrates have no selectivity for SERS enhancement and poor anti-interference ability. The sensitivity, specificity and repeatability of foodborne pathogenic bacteria fingerprint signals will be affected by complex environments. Therefore, ordinary SERS substrates are difficult to be directly used for the collection of SERS fingerprints of foodborne pathogens in complex samples.

[0004] In recent years, researchers have begun to use surface-modified SERS substrates to separate bacteria from complex environments and complete SERS detection, such as antibodies, phages and other recognition molecules to modify the surface of metal nanostructures, but these recognition molecules are costly and require high operation. Vancomycin, as a glycopeptide antibacterial drug, has the advantages of good stability, low cost, and controllable quality. Its carboxyl group forms a hydrogen bond complex with the end of the bacterial cell wall component muramyl pentapeptide (D-Ala-D-Ala) and firmly binds. Therefore, vancomycin-modified SERS substrates can be used for the capture and detection of foodborne pathogens. On the other hand, polydimethylsiloxane (PDMS) has received widespread attention as a supporting material for SERS-active nanoparticles. It is stable, simple to prepare, has good Raman inertness and enrichment of aqueous analytes. Using PDMS membrane as a solid substrate, combining Au@AgNPs sol with a core-shell structure and good SERS enhancement effect with vancomycin with a broad-spectrum capture ability, an Au@AgNPs-Van / PDMS thin film SERS detection platform with efficient capture, enrichment and SERS fingerprint detection is synthesized to achieve the capture of foodborne pathogens in complex environments, which is an effective way to solve the limitations of SERS applications. Summary of the invention

[0005] The purpose of the present invention is to provide a preparation method and application of an Au@AgNPs-Van / PDMS thin film SERS detection platform. By designing the steps of adding and recovering foodborne pathogens in an actual complex environment, the rapid capture, enrichment and SERS fingerprint detection of foodborne pathogens in an actual complex matrix are achieved. The SERS substrate material prepared by the present invention has high sensitivity and good reproducibility, and can efficiently qualitatively and quantitatively detect foodborne pathogens in a complex environment, providing technical support for the rapid and highly sensitive detection application of SERS technology in a complex environment.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for preparing an Au@AgNPs-Van / PDMS thin film SERS detection platform comprises the following steps:

[0008] (1) Synthesis of Au@AgNPs sol. Add 99 mL of deionized water and 1 mL of chloroauric acid (1%, wt%) into a clean conical flask and heat to boiling on an electromagnetic heating stirrer at a stirring speed of 600 rpm. Quickly add 1.5 mL of sodium citrate solution (1%, wt%) to the boiling chloroauric acid solution and continue heating for 15-20 min to prepare an AuNPs sol solution. Then take 50 mL of the above-prepared AuNPs solution and add 150 mL of deionized water and 2 mL of sodium citrate (1%, wt%), heat to boiling and stir at a stirring speed of 600 rpm. Weigh 2 mg of silver nitrate and dissolve it in 1 mL of deionized water, and quickly add the silver nitrate solution dropwise to the above boiling solution and continue boiling for 30-40 min. Then turn off the heater, continue stirring the reaction solution to room temperature, and then add deionized water to make the liquid volume return to 200 mL, which is the Au@AgNPs sol.

[0009] (2) Synthesis of Au@AgNPs-Van solution. 10 mg of Au@AgNPs sol was added with 10 mL of 11-mercaptoundecanoic acid (MUA) ethanol solution (40 μM). After ultrasonic reaction for 1.5 to 2 hours, it was washed with anhydrous ethanol and ultrapure water three times to remove unreacted MUA. The obtained Au@AgNPs-MUA particles were dissolved in 2-(N-morpholino)ethanesulfonic acid (MES) buffer (0.1 M, pH 5.5) and ultrasonicated for 10 to 15 min to completely disperse them. 1 mL of carbodiimide (EDC) aqueous solution (10 mg / mL) and 1 mL of vancomycin solution (Van, 5 mg / mL) were added in sequence and ultrasonic reaction was continued for 1.5 to 2 hours. After washing with ultrapure water three times, Au@AgNPs-Van was prepared for use.

[0010] (3) Construct an Au@AgNPs-Van / PDMS film SERS detection platform. The PDMS film was treated with a plasma cleaner (30W, 10 min) to improve its surface hydrophilicity. The surface was covered with a layer of tightly packed hydroxyl groups (-OH). The hydrophilic PDMS membrane was placed in a 5% APTMS solution and incubated overnight with shaking. After being taken out, it was washed three times with anhydrous ethanol and pure water. The APTMS solution can silanize the surface of the PDMS membrane. The methoxy group in APTMS is easily hydrolyzed. The silanol (Si-OH) produced by hydrolysis is hydrogen bonded to the hydroxyl group of the PDMS membrane, and the APTMS is assembled on the surface of the PDMS membrane, exposing the amino group (-NH2) at the end.

[0011] (4) The treated PDMS membrane was placed in the Au@AgNPs-Van solution. A strong chemical interaction occurred between the Ag on the surface of the Au@AgNPs sol and the exposed amino groups of APTMS, which triggered the self-assembly of Au@AgNPs on the surface of the PDMS film. The Au@AgNPs sol was adsorbed on the PDMS membrane, thereby constructing a "PDMS-Au@AgNPs-Van" sandwich structure. After 4 hours, the Au@Ag NPs-Van / PDMS film was taken out.

[0012] The Au@AgNPs-Van / PDMS thin film SERS detection platform described in the present invention is applied in complex environments. Based on the Au@Ag NPs-Van / PDMS thin film SERS detection platform as the SERS substrate, laser confocal Raman is used for the following three aspects of detection and analysis: (1) Practical application of the Au@AgNPs-Van / PDMS thin film SERS detection platform for rapid identification of three foodborne pathogens; (2) Application of SERS quantitative identification using Staphylococcus aureus as an example.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] The present invention constructs an Au@AgNPs-Van / PDMS thin film SERS detection platform, designs the steps of spike recovery of foodborne pathogens in actual complex matrices, and realizes the application of the Au@AgNPs-Van / PDMS thin film SERS detection platform in the rapid capture, enrichment and SERS detection of foodborne pathogens in actual beef samples. This forms a new method for the rapid capture, enrichment and detection of foodborne pathogens in a complex solution environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Schematic diagram of the molecular structure of 11-mercaptoundecanoic acid (MUA) and vancomycin (Van).

[0016] Figure 2 Schematic diagram of the principle of vancomycin (Van) modified Au@AgNP sol.

[0017] Figure 3 Schematic diagram of the preparation process of Au@AgNPs-Van / PDMS film SERS detection platform. (A) Schematic diagram of hydrophilic treatment and surface silanization of PDMS film (B) Schematic diagram of Au@AgNPs-Van assembly on PDMS film.

[0018] Figure 4 Characterization of Au@AgNPs sol, Van solution and Au@AgNPs-Van / PDMS film. (A) Particle size distribution of Au@AgNPs; (B) Transmission electron microscopy of Au@AgNPs; (C) UV-visible spectra of Au@AgNPs sol, Van solution and Au@AgNPs-Van solution; (D) SEM of Au@AgNPs / PDMS film.

[0019] Figure 5 Schematic diagram of the SERS spectroscopy detection process of foodborne pathogens in beef samples using the Au@AgNPs-Van / PDMS thin film SERS platform.

[0020] Figure 6 This is the average fingerprint spectrum of SERS detection of three foodborne pathogens using laser confocal Raman spectrometer based on Au@AgNPs-Van / PDMS film SERS detection platform.

[0021] Figure 7 The reproducible results of SERS detection of three foodborne pathogens based on Au@AgNPs-Van / PDMS film SERS detection platform. (A) Clostridium perfringens ( C. perfringens ) of SERS spectra reproducibility test; (B) of Bacillus subtilis ( B. subtilis ) SERS spectrum reproducibility test; (C) Staphylococcus aureus ( S. aureus )’s SERS spectrum reproducibility test.

[0022] Figure 8 To investigate the growth and residue of Staphylococcus aureus during the spike recovery process of actual beef samples.

[0023] Fig. 9 The SERS detection results of Staphylococcus aureus of different concentrations based on Au@AgNPs-Van / PDMS film SERS detection platform. Fig. 9(A) is the Raman spectrum of Staphylococcus aureus at different concentrations measured based on the Au@AgNPs-Van / PDMS film SERS detection platform; Fig. 9 (B) The logarithmic values ​​of Staphylococcus aureus concentrations and their SERS spectra at 1531 cm -1 The Raman intensity at is plotted in a linear relationship. DETAILED DESCRIPTION

[0024] The present invention will be further described below in conjunction with specific embodiments. It should be understood that the following embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention, and those skilled in the art in this field can make some non-essential improvements and adjustments based on the content of the above invention.

[0025] Example 1

[0026] like Figure 2-3 The schematic diagram and process diagram of the preparation method of the Au@AgNPs-Van / PDMS thin film SERS detection platform are shown, which include the following steps:

[0027] (1) Synthesis of Au@AgNPs sol. Add 99 mL of deionized water and 1 mL of chloroauric acid (1%, wt%) into a clean conical flask and heat to boiling on an electromagnetic heating stirrer at a stirring speed of 600 rpm. Quickly add 1.5 mL of sodium citrate solution (1%, wt%) to the boiling chloroauric acid solution and continue heating for 15-20 min to prepare an AuNPs sol solution. Then take 50 mL of the above-prepared AuNPs solution and add 150 mL of deionized water and 2 mL of sodium citrate (1%, wt%), heat to boiling and stir at a stirring speed of 600 rpm. Weigh 2 mg of silver nitrate and dissolve it in 1 mL of deionized water, and quickly add the silver nitrate solution dropwise to the above boiling solution and continue boiling for 30-40 min. Then turn off the heater, continue stirring the reaction solution to room temperature, and then add deionized water to make the liquid volume return to 200 mL, which is the Au@AgNPs sol.

[0028] (2) Synthesis of Au@AgNPs-Van solution. 10 mg of Au@AgNPs sol was added to 10 mL of 11-mercaptoundecanoic acid (MUA) ethanol solution (40 μM). After ultrasonic reaction for 1.5 to 2 hours, it was washed three times with anhydrous ethanol and ultrapure water to remove unreacted MUA. The obtained Au@AgNPs-MUA particles were dissolved in 2-(N-morpholino)ethanesulfonic acid (MES) buffer (0.1 M, pH 5.5) and ultrasonicated for 10 to 15 min to completely disperse them. 1 mL of carbodiimide (EDC) aqueous solution (10 mg / mL) and 1 mL of vancomycin solution (Van, 5 mg / mL) were added in sequence and ultrasonic reaction was continued for 1.5 to 2 hours. The Au@AgNPs-Van solution was washed three times with ultrapure water for use. In the method of synthesizing Au@AgNPs-Van solution, 11-mercaptoundecanoic acid (MUA) has a bidirectional modification effect, which can couple vancomycin to the terminal carboxyl group of MUA through an amide condensation reaction. MUA is a commonly used multifunctional modification chain. One end of the thiol group can be firmly bound to the Ag shell surface through an Ag-S bond, and the other end is a carboxyl group that can provide a site for coupling vancomycin. EDC solution can activate and promote the chemical coupling between vancomycin and MUA (such as Figure 1 and Figure 2 as shown).

[0029] (3) Construct an Au@AgNPs-Van / PDMS film SERS detection platform. Treat the PDMS film with a plasma cleaner (30W, 10 min) to improve its surface hydrophilicity. Cover its surface with a layer of tightly packed hydroxyl groups (-OH). Place the hydrophilically treated PDMS membrane in 5% APTMS, incubate overnight with shaking, and then take it out and wash it three times with anhydrous ethanol and pure water. The APTMS solution can silanize the surface of the PDMS membrane. The methoxy group of APTMS is easily hydrolyzed. The silanol (Si-OH) produced by hydrolysis combines with the hydroxyl group of the PDMS membrane in the form of hydrogen bonds, assembling the APTMS on the surface of the PDMS membrane, exposing the amino group (-NH2) at the end. Figure 3 (A) shown.

[0030] (4) The treated PDMS film was placed in the Au@AgNPs-Van solution. A strong chemical interaction occurred between the Ag on the surface of the Au@AgNPs and the amino groups exposed by the APTMS, which triggered the self-assembly of the Au@AgNPs on the surface of the PDMS film. The Au@AgNPs were able to adsorb on the PDMS film, thereby constructing a "PDMS-Au@AgNPs-Van" sandwich structure. After 4 hours, the Au@Ag NPs-Van / PDMS film was obtained. Figure 3 (B) shown.

[0031] The Au@AgNPs sol, Au@AgNPs-Van solution and Au@AgNPs-Van / PDMS film obtained in the above steps were characterized respectively, and the characterization results were as follows: Figure 4 As shown. Among them, Figure 4 The results of (A) and (B) show that the Au@AgNPs sol presents a Au core-Ag shell sandwich spherical structure. The particle size of Au@AgNPs is mainly distributed in the range of 35-85 nm, with an average size of about 69 nm. Figure 4 (C) The results show that the UV-visible absorption spectrum of Au@AgNPs sol has SPR absorption peaks at 420 nm and 517 nm. After incubation with vancomycin (Van) solution, Au@AgNPs sol has a new absorption peak at 280 nm compared with that before incubation. After Van is activated in the EDC buffer system, it can bind to the gold nanoparticles on the surface of Au@AgNPs through the Ag-S bond, thereby fixing Van on the surface of Au@AgNPs sol, proving the successful binding of Van to Au@AgNPs sol. Figure 4 (D) The results show that the SEM electron microscopy image shows that the Au@AgNPs-Van particles are evenly distributed on the surface of the PDMS film, indicating that the Au@AgNPs-Van / PDMS film was successfully prepared.

[0032] Example 2

[0033] Cultivation of foodborne pathogens: Clostridium perfringens, Bacillus subtilis and Staphylococcus aureus stored in -80 ℃ magnetic beads were cultured in FTG liquid medium, LB liquid medium and TSB liquid medium in a 37 ℃ incubator for 18 h. The enrichment solution of the three foodborne pathogens was washed three times by centrifugation with sterile saline, resuspended and diluted to a suitable gradient, 100 μL of each was evenly spread on the plate culture medium, placed in a 37 ℃ incubator for 24 h, and the initial bacterial solution concentration was calculated based on the number of colonies grown. The remaining bacterial suspension was aliquoted and stored in a 4 ℃ refrigerator for later use.

[0034] Sample spike recovery setup: 5 g of fresh beef was placed in a sterile bag and irradiated with UV light on both sides for 30 min each to eliminate the interference of bacteria. Then, it was crushed and homogenized on a sterile operating table, and 45 mL of sterile water was added to mix and package. 9 mL of homogenized beef suspension was taken and 1 mL of 10 8CFU / mL Clostridium perfringens, Bacillus subtilis and Staphylococcus aureus were mixed and filtered twice with a 3 μm sterile microporous filter membrane (bacterial suspension: sterile distilled water volume ratio 1:10), and the filtrate was collected. In the clean bench, 200 μm filtrate was taken and dripped on the Au@AgNPs-Van / PDMS film that had been sterilized by UV in advance. After standing for a period of time, it was rinsed three times in 9 mL sterile water, and the SERS spectrum was collected after drying. Figure 5 shown.

[0035] Before the sample was tested, the -1 The peak was used as the reference peak to calibrate the Raman instrument using silicon wafer (Si). The surface enhanced Raman spectra were collected using 532.8 cm -1 The laser was used as the excitation light source, the laser intensity was set to the maximum intensity (15 mW), the objective lens was set to 100 times, the integration time was 30 s, and the integration was performed 3 times. The detected spectrum was 400-1800 cm -1 , resolution 1cm -1 The prepared samples were tested on the machine, and then the spectra of the samples were collected using LabSpec 6.0 software. Each sample was randomly collected 12 times.

[0036] Figure 6 The results show that the Raman vibration peak position and peak intensity in the average fingerprint spectrum of the three foodborne pathogens detected by SERS detection using a laser confocal Raman spectrometer based on the Au@AgNPs-Van / PDMS film SERS detection platform are significantly different, and the Raman signals and characteristics of different foodborne pathogens can be clearly distinguished, indicating that the SERS technology based on Au@AgNPs-Van / PDMS film has the ability to detect and distinguish different types of foodborne pathogens in actual beef samples. Figure 7 The results showed that the Au@AgNPs-Van / PDMS film substrate material had good reproducibility in SERS detection of three foodborne pathogens, indicating that the SERS technology based on Au@AgNPs-Van / PDMS film as the substrate material has good reproducibility in detecting foodborne pathogens, providing strong support for the rapid detection of foodborne pathogens based on SERS technology.

[0037] Example 3

[0038] The capture efficiency of Staphylococcus aureus in beef samples was detected using the Au@AgNPs-Van / PDMS thin film SERS detection platform. The specific steps are as follows: The capture efficiency of the SERS substrate affects the detection sensitivity of foodborne pathogens. In order to study the capture efficiency of the Au@AgNPs-Van / PDMS thin film SERS detection platform for foodborne pathogens, this example uses Staphylococcus aureus as the detection object. The culture, purification and spike recovery of Staphylococcus aureus are carried out according to the method in Example 2. The number of microorganisms (C) that have not been filtered after the beef suspension is reversed with Staphylococcus aureus, the residual microorganisms in the filtrate (C1) and the residual microorganisms in the rinse liquid (C2) are counted by the microbial "gold standard" detection method plate counting method. The filtration rate (FR) is calculated by the formula FR=C1 / C×100%, and the capture efficiency (CE) can be calculated by CE=(C1-C2) / C1×100%. The results are shown in Figure 8 The filtration rate (FR) is 71.17%, and the capture efficiency (CE) of Au@AgNPs-Van / PDMS film for Staphylococcus aureus is about 69.4%.

[0039] Example 4

[0040] On the basis of Example 3, Staphylococcus aureus solutions of different concentrations were evenly mixed with beef filtrate in a ratio of 1 mL:9 mL, and then the Au@AgNPs-Van / PDMS thin film SERS detection platform was used to quantitatively detect Staphylococcus aureus in the beef sample, and SERS spectrum collection was performed according to Example 2.

[0041] Fig. 9 The SERS detection results of Staphylococcus aureus of different concentrations based on Au@AgNPs-Van / PDMS film SERS detection platform. Fig. 9 (A) SERS spectra of Staphylococcus aureus with different concentrations captured by Au@AgNPs-Van / PDMS film at 10 1 ~10 5 In the concentration range of CFU / mL, the SERS spectrum intensity of Staphylococcus aureus increases with the increase of concentration. 9 (B) shows the logarithmic value of different concentrations of Staphylococcus aureus on Au@AgNPs-Van / PDMS film substrate and its peak at 1531 cm -1 The SERS intensity at the position has a good linear relationship, y = 3859.58x -1956.23, R2 = 0.96. The detection of Staphylococcus aureus on this substrate can be as low as 1.30×10 1CFU / mL. Combining the filtration rate and capture efficiency, the detection limit of Au@AgNPs-Van / PDMS film in the reagent beef sample was calculated to be 2.60×10 1 CFU / mL. This indicates that the Au@AgNPs-Van / PDMS film SERS detection platform has the potential to quantitatively analyze foodborne pathogens.

[0042] The above is only a preferred specific implementation of the present invention and is not intended to limit the scope of the invention. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solution and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be protected by the present invention.

Claims

1. Application of Au@AgNPs-Van / PDMS film SERS detection platform in rapid identification of three foodborne pathogens, characterized by: The three foodborne pathogens are Clostridium perfringens, Bacillus subtilis and Staphylococcus aureus; The preparation method of the Au@AgNPs-Van / PDMS thin film SERS detection platform comprises the following steps: (1) Preparation of Au@AgNPs sol; (2) Synthesis of Au@AgNPs-Van solution: The Au@AgNPs sol prepared in (1) was added to 11-mercaptoundecanoic acid (MUA) ethanol solution, and the Au@AgNPs-MUA particles were obtained by ultrasonic reaction. The Au@AgNPs-MUA particles were dissolved in 2-(N-morpholino)ethanesulfonic acid (MES) buffer and ultrasonically dispersed. Then, an aqueous solution of carbodiimide (EDC) and a vancomycin solution were added and ultrasonically reacted, and then washed with water to obtain the Au@AgNPs-Van solution. (3) Construction of Au@AgNPs-Van / PDMS thin film SERS detection platform: The PDMS membrane was hydrophilized and placed in 3-aminopropyl-trimethoxysilane (APTMS). The membrane was shaken and incubated overnight. After washing, the membrane was placed in Au@AgNPs-Van solution. The Au@Ag NPs-Van / PDMS thin film was obtained after the reaction.

2. The use according to claim 1, characterized in that: Step (1) The preparation method of Au@AgNPs sol is as follows: 99 mL of deionized water and 1 mL of 1% chloroauric acid solution were added to a clean conical flask and heated to boiling on an electromagnetic heating stirrer at a stirring speed of 600 rpm. 1.5 mL of 1% sodium citrate solution was quickly added to the boiling chloroauric acid solution and heated for 15 to 20 min to prepare an AuNPs sol solution. Then 50 mL of the AuNPs solution prepared above was added to 150 mL of deionized water and 2 mL of 1% sodium citrate solution, heated to boiling and stirred at a stirring speed of 600 rpm. 2 mg of silver nitrate was weighed and dissolved in 1 mL of deionized water, and the silver nitrate solution was quickly added dropwise to the boiling solution, and boiling was continued for 30 to 40 min. The heater was then turned off, the reaction solution was stirred to room temperature, and deionized water was added to adjust the volume of the liquid back to 200 mL, which was the Au@AgNPs sol.

3. The use according to claim 1, characterized in that: In step (2), 10 mg of Au@AgNPs sol was added to 10 mL of 11-mercaptoundecanoic acid (MUA) ethanol solution, and then ultrasonically reacted for 1.5 to 2 hours, and then washed with anhydrous ethanol and ultrapure water three times to remove unreacted MUA; the obtained Au@AgNPs-MUA particles were dissolved in 2-(N-morpholino)ethanesulfonic acid (MES) buffer with a pH of 5.5 and a concentration of 0.1 M, and ultrasonicated for 10 to 15 min to completely disperse them; 1 mL of carbodiimide (EDC) aqueous solution and 1 mL of vancomycin (Van) solution were added in sequence, and the ultrasonic reaction was continued for 1.5 to 2 hours, and then washed with ultrapure water three times to obtain Au@AgNPs-Van solution for use.

4. The use according to claim 3, characterized in that: The concentration of the ethanol solution of 11-mercaptoundecanoic acid was 40 μM, the concentration of the aqueous carbodiimide solution was 10 mg / mL, and the concentration of the vancomycin solution was 5 mg / mL.

5. The use according to claim 1, characterized in that: The method for hydrophilizing the PDMS film in step (3) is as follows: the PDMS film is treated with a plasma cleaner at 30 W for 10 min, so that its surface is covered with a layer of closely arranged hydroxyl groups (-OH) to improve its surface hydrophilicity.

6. The use according to claim 1, characterized in that: In step (3), the mass concentration (wt%) of 3-aminopropyl-trimethoxysilane (APTMS) is 5%, and the reaction time is 4 hours.

7. Application of the Au@AgNPs-Van / PDMS thin film SERS detection platform described in claim 1 to SERS quantitative identification of Staphylococcus aureus.

Images