A thin film material for surface-enhanced Raman detection of viral proteins and its preparation method

Abstract

The present invention discloses a thin film material for surface-enhanced Raman detection of viral proteins and a preparation method thereof. The thin film material consists of two parts: a PMMA film and a gold nano-Ti3C2Tx layered composite material. The Ti3C2Tx layer spacing is 100-150 nanometers, the surface has a large number of nanometer-level gap structures, and the diameter of the gold nanowire is 5 nanometers. Its advantage is that the layered structure of Ti3C2Tx has a large surface area and provides more adsorption sites for gold nanoparticles, which is conducive to the dense growth of gold nanowires and the adsorption of molecules to be tested. The aggregated gold nanowires have a large number of tip structures, which are conducive to obtaining an enhanced gold nanoparticle surface plasmon resonance electromagnetic field, greatly enhancing the Raman signal of the adsorbed molecules. Due to the fixed Raman peak, the introduction of the PMMA film can provide an internal standard peak, improving the accuracy of the detection. The operation is simple, the repeatability is good, and it is suitable for large-scale applications.

Description

Technical Field

[0001] The present invention belongs to the fields of material engineering and nanotechnology, and particularly relates to a thin film material for surface-enhanced Raman detection of viral proteins and a preparation method thereof. Background Art

[0002] Surface-enhanced Raman scattering (SERS) technology combines the advantages of high sensitivity and informative characteristic spectra and has been widely used for ultrasensitive detection of biomolecules, monitoring of chemical reactions, in-situ determination of pesticides, and so on. The most commonly used surface-enhanced Raman scattering (SERS) substrates are gold or silver nanomaterials because they have a strong localized surface plasmon resonance effect (LSRP) and a high electromagnetic enhancement effect. At the same time, two-dimensional carbon nitride (MXene) materials with a metal-like band structure have a surface plasmon resonance effect (SRP) and can be used as a functional substrate for SERS, with excellent chemical enhancement effects. The synergistic enhancement effect of electromagnetics and chemistry is conducive to improving the sensitivity of SERS detection and enhancing the surface electromagnetic field excitation efficiency of precious metal nanomaterials. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a thin film material for surface enhanced Raman detection of viral proteins and a preparation method thereof.

[0004] The technical solution adopted by the present invention to solve the above technical problems is: a thin film material for surface-enhanced Raman detection of viral proteins, which is composed of two parts: a polymethyl methacrylate (PMMA) film and a Ti3C2Tx layered composite material loaded with gold nanowires. The Ti3C2Tx layer spacing is 100-150 nanometers, and the surface has a large number of nano-level gap structures. The diameter of the gold nanowires is 5 nanometers.

[0005] The method for preparing the thin film loaded with gold nanowire Ti3C2Tx layered composite material for surface enhanced Raman detection comprises the following steps:

[0006] 1) Preparation of Ti3C2Tx layered material: Lithium fluoride was added to a certain amount of hydrochloric acid and stirred for 10 minutes until the lithium fluoride was completely dissolved. Titanium aluminum carbide was slowly added to the above solution and stirring was continued at 35°C for 48 hours. The reaction precipitate was centrifuged and washed with deionized water until the pH of the supernatant reached 6. The precipitate was collected and air-dried to obtain the Ti3C2Tx layered material. It was dissolved in a certain amount of deionized water to form a black Ti3C2Tx solution.

[0007] 2) Preparation of a gold nanowire Ti3C2Tx layered composite material: A certain amount of 3-aminopropyltriethoxysilane was added to a mixture of ethanol and deionized water in a 1:1 volume ratio, stirred at room temperature for ten minutes, and then added to a sodium citrate solution in deionized water. The mixture was stirred at room temperature for ten minutes, followed by a sodium borohydride solution to prepare a gold seed solution. The solution was stirred at room temperature for half an hour, then allowed to stand for three hours. A certain amount of 4-mercaptobenzoic acid was dissolved in ethanol, and then a certain amount of L-ascorbic acid was dissolved in deionized water. A silicon wafer was soaked in 3-aminopropyltriethoxysilane for 1.5 hours, then rinsed in ethanol and deionized water, and dried. The Ti3C2Tx solution prepared in step 1) was dripped onto the treated silicon wafer, allowed to stand for 10 minutes, and then dried. The dried silicon wafer was soaked in 3-aminopropyltriethoxysilane for 1.5 hours, then rinsed in ethanol and deionized water, and dried. The silicon wafer was then immersed in the gold seed solution and, after 1.5 hours, rinsed in ethanol and deionized water, followed by drying. A certain amount of 4-mercaptobenzoic acid was dissolved in ethanol, and chloroauric acid solution was added, stirred for 10 minutes. The silicon wafer was then added, followed by L-ascorbic acid solution. After standing for 30 minutes, the mixture was rinsed in ethanol and deionized water, followed by drying, to obtain a gold nanowire Ti3C2Tx layered composite material.

[0008] 3) Preparation of a gold nanowire-loaded Ti3C2Tx layered composite film: PMMA was dissolved in toluene and ultrasonicated for 2 hours. A certain amount of the PMMA solution was dropped onto a silicon wafer, cooled at room temperature, and the PMMA film was peeled off the silicon wafer. A certain amount of the gold nanowire-loaded Ti3C2Tx layered composite prepared in step 2) was ultrasonically dispersed in deionized water and coated onto the PMMA film to obtain a gold nanowire-loaded Ti3C2Tx layered composite film suitable for SERS detection.

[0009] Step 1) specifically involves adding lithium fluoride (1.98 g) to a certain amount of hydrochloric acid (20 ml, 9 mol / L) and stirring for 10 minutes until the lithium fluoride is completely dissolved. Titanium aluminum carbide (2 g) is slowly added to the above solution, and stirring is continued at 35°C for 48 hours. The reaction precipitate is centrifuged and washed with deionized water until the pH value of the supernatant is 6. The precipitate is collected and naturally dried to obtain a Ti3C2Tx layered material, which is dissolved in a certain amount of deionized water to form a black Ti3C2Tx solution (10 mg / ml).

[0010] Step 2) specifically comprises: adding a certain amount of 3-aminopropyltriethoxysilane (10 μL) to a 1:1 volume ratio of ethanol and deionized water (10 mL) and stirring at room temperature for ten minutes. Sodium citrate solution (100 μL, 14.7 mg / mL) is added to deionized water (20 mL), followed by a chloroauric acid solution (19.7 μL, 100 mg / mL). After stirring at room temperature for ten minutes, sodium borohydride solution (600 μL, 3.783 mg / mL) is added to prepare a gold seed solution. After stirring at room temperature for half an hour, the solution is allowed to stand for three hours. A certain amount of 4-mercaptobenzoic acid (7.7 mg) is dissolved in ethanol (10 mL) and set aside. A certain amount of L-ascorbic acid (0.035 g) is dissolved in deionized water (10 mL) and set aside. The silicon wafer was soaked in 3-aminopropyltriethoxysilane, and after 1.5 hours, it was washed and dried in ethanol solution and deionized water respectively. The Ti3C2Tx solution (10 μL) obtained in step 1) was dripped onto the treated silicon wafer, left to stand for 10 minutes, and then dried. The dried silicon wafer was soaked in 3-aminopropyltriethoxysilane, and after 1.5 hours, it was washed and dried in ethanol solution and deionized water respectively. The silicon wafer was then placed in the gold seed solution for soaking, and after 1.5 hours, it was washed and dried in ethanol solution and deionized water respectively. A certain amount of 4-mercaptobenzoic acid (200 μL) was dissolved in ethanol (1 mL), and chloroauric acid solution (50 μL, 17 mg / mL) was added and stirred for 10 minutes. The above silicon wafer was added, and then L-ascorbic acid solution (300 μL, 3.5 mg / mL) was added. After standing for 30 minutes, it was washed and dried in ethanol solution and deionized water respectively to obtain a gold nanowire Ti3C2Tx layered composite material.

[0011] Step 3) specifically involves dissolving PMMA (0.9 g) in a toluene solution (21 ml) and sonicating for 2 hours. A certain amount of the PMMA solution (5 μl) is then dropped onto a silicon wafer, cooled to room temperature, and the PMMA film is peeled off from the silicon wafer. A certain amount of the gold nanowire-Ti3C2Tx layered composite material (0.01 mg) prepared in step 2) is ultrasonically dispersed in deionized water (100 μl) and coated onto the surface of the PMMA film. This yields a thin film loaded with the gold nanowire-Ti3C2Tx layered composite material suitable for SERS detection.

[0012] Furthermore, the present invention also provides the use of the prepared thin film loaded with gold nanowire Ti3C2Tx layered composite material for surface enhanced Raman detection of viral proteins (such as the new coronavirus antigen N protein, i.e., SARS-CoV-2-N), specifically as follows: a certain amount of SARS-CoV-2-N protein is dropped on a thin film loaded with gold nanowire Ti3C2Tx layered composite material, and dried at room temperature for 2 hours; the dried thin film is placed in a Raman spectrometer, and its Raman signal is recorded at a laser wavelength of 532nm.

[0013] Compared with the prior art, the advantages of the present invention are:

[0014] This invention discloses for the first time a thin film material that can be used for surface-enhanced Raman detection of viral proteins. The film material consists of a PMMA film and a layered composite material loaded with gold nanoparticles (Ti3C2Tx). The Ti3C2Tx layer spacing is 100-150 nanometers, with numerous nanoscale interstitial structures on the surface. The gold nanowires are 5 nanometers in diameter. The advantage lies in the large surface area of ​​the Ti3C2Tx layered structure, which provides numerous adsorption sites for gold nanoparticles, facilitating the dense growth of gold nanowires and the adsorption of target molecules. The aggregated gold nanowires have numerous apical structures, which enhance the surface plasmon resonance electromagnetic field of the gold nanoparticles, significantly enhancing the Raman signal of the adsorbed molecules. The film material possesses specific detection properties due to its specific gold nanowire and gold nanoparticle composition. It has a fixed Raman peak, and the PMMA film provides an internal standard peak, improving detection accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is the surface enhanced Raman test result of the gold nanowire Ti3C2Tx layered composite material, gold nanowires, and Ti3C2Tx prepared in Example 1 of the present invention on the new coronavirus antigen N protein (SARS-CoV-2-N protein);

[0016] Figure 2 This is a scanning electron microscope photograph of a thin film of a gold nanowire-loaded Ti3C2Tx layered composite material prepared in Example 1 of the present invention;

[0017] Figure 3 This is the Raman detection result of the thin film loaded with gold nanowire Ti3C2Tx layered composite material prepared in Example 1 of the present invention;

[0018] Figure 4 This is a scanning electron microscope photograph of a thin film of a gold nanowire-loaded Ti3C2Tx layered composite material prepared in Example 2 of the present invention;

[0019] Figure 5 This is the Raman detection result of the thin film of the gold nanowire-loaded Ti3C2Tx layered composite material prepared in Example 2 of the present invention;

[0020] Figure 6 This is a scanning electron microscope photograph of a thin film of a gold nanowire-loaded Ti3C2Tx layered composite material prepared in Example 3 of the present invention;

[0021] Figure 7This is the Raman detection result of the thin film of the gold nanowire-loaded Ti3C2Tx layered composite material prepared in Example 3 of the present invention. DETAILED DESCRIPTION

[0022] The present invention will be described in further detail below with reference to the accompanying drawings and embodiments.

[0023] The following examples are used to illustrate the present invention, but are not intended to limit the scope of the invention. Unless otherwise specified, the technical means used in the examples are conventional means well known to those skilled in the art, and the raw materials used are all commercially available products. By integrating a polymer film with an internal standard onto a SERS substrate, reliable quantitative detection can be achieved. Therefore, we combined a polymethyl methacrylate (PMMA) polymer film with an internal standard with a Ti3C2Tx layered material with a chemical enhancement effect and gold nanowires with excellent SERS activity to produce a Raman substrate with excellent SERS activity. The above-mentioned film substrate loaded with gold nanowire Ti3C2Tx layered composite material effectively and reliably realizes the identification of virus particles. The specific scheme is described in detail below.

[0024] Example 1

[0025] The preparation method of the thin film loaded with gold nanowire Ti3C2Tx layered composite material comprises the following steps:

[0026] 1. Preparation of Ti3C2Tx layered material: Lithium fluoride (1.98 g) was added to a certain amount of hydrochloric acid (20 ml, 9 mol / L) and stirred for 10 minutes until the lithium fluoride was completely dissolved. Titanium aluminum carbide (2 g) was slowly added to the above solution and continued to stir at 35°C for 48 hours. The reaction precipitate was centrifuged and washed with deionized water until the pH value of the supernatant was 6. The precipitate was collected and naturally dried to obtain the Ti3C2Tx layered material, which was dissolved in a certain amount of deionized water to form a black Ti3C2Tx solution (10 mg / ml);

[0027] 2. Preparation of gold nanowire Ti3C2Tx layered composite material: 10 μL of 3-aminopropyltriethoxysilane was added to a 1:1 (volume ratio) mixture of ethanol and deionized water (10 mL) and stirred at room temperature for ten minutes. Sodium citrate solution (100 μL, 14.7 mg / mL) was added to deionized water (20 mL), followed by chloroauric acid solution (19.7 μL, 100 mg / mL). After stirring at room temperature for ten minutes, sodium borohydride solution (600 μL, 3.783 mg / mL) was added to prepare a gold seed solution. The solution was stirred at room temperature for half an hour and allowed to stand for three hours. 7.7 mg of 4-mercaptobenzoic acid was dissolved in 10 mL of ethanol and L-ascorbic acid (0.035 g) was dissolved in 10 mL of deionized water. The silicon wafer was soaked in 3-aminopropyltriethoxysilane, and after 1.5 hours, it was washed and dried in ethanol solution and deionized water respectively. The Ti3C2Tx solution (10 μL) obtained in step 1) was dripped onto the treated silicon wafer, left to stand for 10 minutes, and then dried. The dried silicon wafer was soaked in 3-aminopropyltriethoxysilane, and after 1.5 hours, it was washed and dried in ethanol solution and deionized water respectively. The silicon wafer was then placed in the gold seed solution for soaking, and after 1.5 hours, it was washed and dried in ethanol solution and deionized water respectively. A certain amount of 4-mercaptobenzoic acid (200 μL) was dissolved in ethanol (1 mL), and chloroauric acid solution (50 μL, 17 mg / mL) was added and stirred for 10 minutes. The above silicon wafer was added, and then L-ascorbic acid solution (300 μL, 3.5 mg / mL) was added. After standing for 30 minutes, it was washed and dried in ethanol solution and deionized water respectively to obtain a gold nanowire Ti3C2Tx layered composite material.

[0028] 3. Preparation of a gold nanowire-loaded Ti3C2Tx layered composite film: PMMA (0.9 g) was dissolved in a toluene solution (21 ml) and sonicated for 2 hours. A certain amount of the PMMA solution (5 μl) was dropped onto a silicon wafer, cooled to room temperature, and the PMMA film was peeled off from the silicon wafer. A certain amount of the gold nanowire-loaded Ti3C2Tx layered composite material (0.01 mg) prepared in step 2) was ultrasonically dispersed in deionized water (100 μl) and coated onto the PMMA film to obtain a gold nanowire-loaded Ti3C2Tx layered composite film suitable for SERS detection.

[0029] The thin film of the gold nanowire-loaded Ti3C2Tx layered composite material prepared in this embodiment consists of two parts: a PMMA film and a gold nanowire-loaded Ti3C2Tx layered composite material. The Ti3C2Tx layer spacing is 100-150 nanometers, the surface has a large number of nanoscale gap structures, and the diameter of the gold nanowire is 5 nanometers.

[0030] The prepared thin film loaded with gold nanowire Ti3C2Tx layered composite material was used for surface enhanced Raman detection of viral proteins such as the novel coronavirus antigen N protein (SARS-CoV-2-N protein), as follows: SARS-CoV-2-N protein (20 μl, 10 -2 mol per liter) was dropped onto a thin film of a gold nanowire Ti3C2Tx layered composite material and dried at room temperature for 2 h. The dried thin film was placed in a Raman spectrometer and its Raman signal was recorded at a laser wavelength of 532 nm.

[0031] Figure 1 The results of surface enhanced Raman detection of SARS-CoV-2-N protein by the gold nanowire Ti3C2Tx layered composite material, gold nanowires, and Ti3C2Tx prepared in this embodiment are shown. Figure 1 It can be seen that compared with the latter two, the gold nanowire-loaded Ti3C2Tx layered composite material has the best SERS enhancement effect on SARS-CoV-2-N protein, which proves the excellent SERS properties of the film loaded with gold nanowire-loaded Ti3C2Tx layered composite material prepared by this patent.

[0032] Figure 2 The scanning electron microscope photo of the gold nanowire Ti3C2Tx layered composite material prepared in this embodiment is shown. Figure 2 It can be seen that gold nanowires are densely distributed on the surface of the Ti3C2Tx layered material.

[0033] Figure 3 The surface enhanced Raman test results of the thin film loaded with gold nanowire Ti3C2Tx layered composite material prepared in this embodiment are shown. Figure 3 It can be seen that the film has a good SERS signal enhancement effect at 1000 cm -1 The Raman signal intensity at 2162.

[0034] Example 2

[0035] The preparation method of the thin film loaded with gold nanowire Ti3C2Tx layered composite material comprises the following steps:

[0036] 1. Preparation of Ti3C2Tx layered material: Lithium fluoride (1.98 g) was added to a certain amount of hydrochloric acid (20 ml, 9 mol / L) and stirred for 10 minutes until the lithium fluoride was completely dissolved. Titanium aluminum carbide (2 g) was slowly added to the above solution and continued to stir at 35°C for 48 hours. The reaction precipitate was centrifuged and washed with deionized water until the pH value of the supernatant was 6. The precipitate was collected and naturally dried to obtain the Ti3C2Tx layered material, which was dissolved in a certain amount of deionized water to form a black Ti3C2Tx solution (10 mg / ml);

[0037] 2. Preparation of gold nanowire Ti3C2Tx layered composite material: 10 μL of 3-aminopropyltriethoxysilane was added to a 1:1 (volume ratio) mixture of ethanol and deionized water (10 mL) and stirred at room temperature for ten minutes. Sodium citrate solution (100 μL, 14.7 mg / mL) was added to deionized water (20 mL), followed by chloroauric acid solution (19.7 μL, 100 mg / mL). After stirring at room temperature for ten minutes, sodium borohydride solution (600 μL, 3.783 mg / mL) was added to prepare a gold seed solution. The solution was stirred at room temperature for half an hour and allowed to stand for three hours. 4-Mercaptobenzoic acid (3.85 mg) was dissolved in ethanol (10 mL) and L-ascorbic acid (0.035 g) was dissolved in deionized water (10 mL). The silicon wafer was soaked in 3-aminopropyltriethoxysilane, and after 1.5 hours, it was washed and dried in ethanol solution and deionized water respectively. The Ti3C2Tx solution (10 μL) obtained in step 1) was dripped onto the treated silicon wafer, left to stand for 10 minutes, and then dried. The dried silicon wafer was soaked in 3-aminopropyltriethoxysilane, and after 1.5 hours, it was washed and dried in ethanol solution and deionized water respectively. The silicon wafer was then placed in the gold seed solution for soaking, and after 1.5 hours, it was washed and dried in ethanol solution and deionized water respectively. A certain amount of 4-mercaptobenzoic acid (200 μL) was dissolved in ethanol (1 mL), and chloroauric acid solution (50 μL, 17 mg / mL) was added and stirred for 10 minutes. The above silicon wafer was added, and then L-ascorbic acid solution (300 μL, 3.5 mg / mL) was added. After standing for 30 minutes, it was washed and dried in ethanol solution and deionized water respectively to obtain a gold nanowire Ti3C2Tx layered composite material.

[0038] 3. Preparation of a gold nanowire-loaded Ti3C2Tx layered composite film: PMMA (0.9 g) was dissolved in a toluene solution (21 ml) and sonicated for 2 hours. A certain amount of the PMMA solution (5 μl) was dropped onto a silicon wafer, cooled to room temperature, and the PMMA film was peeled off from the silicon wafer. A certain amount of the gold nanowire-loaded Ti3C2Tx layered composite material (0.01 mg) prepared in step 2) was ultrasonically dispersed in deionized water (100 μl) and coated onto the PMMA film to obtain a gold nanowire-loaded Ti3C2Tx layered composite film suitable for SERS detection.

[0039] The thin film of the gold nanowire-loaded Ti3C2Tx layered composite material prepared in this embodiment consists of two parts: a PMMA film and a gold nanowire-loaded Ti3C2Tx layered composite material. The Ti3C2Tx layer spacing is 100-150 nanometers, the surface has a large number of nanoscale gap structures, and the diameter of the gold nanowire is 5 nanometers.

[0040] The prepared thin film loaded with gold nanowire Ti3C2Tx layered composite material was used for surface enhanced Raman detection of viral proteins such as the novel coronavirus antigen N protein (SARS-CoV-2-N protein), as follows: SARS-CoV-2-N protein (20 μl, 10 -2 mol per liter) was dropped onto a thin film of a gold nanowire Ti3C2Tx layered composite material and dried at room temperature for 2 h. The dried thin film was placed in a Raman spectrometer and its Raman signal was recorded at a laser wavelength of 532 nm.

[0041] Figure 4 The scanning electron microscope photo of the gold nanowire Ti3C2Tx layered composite material prepared in this embodiment is shown. Figure 4 It can be seen that the gold nanowires are relatively evenly distributed on the surface of the Ti3C2Tx layered material.

[0042] Figure 5 The surface enhanced Raman test results of the thin film loaded with gold nanowire Ti3C2Tx layered composite material prepared in this embodiment are shown. Figure 5 It can be seen that the film has a good SERS signal enhancement effect at 1000 cm -1 The Raman signal intensity at 1705.

[0043] Example 3

[0044] The preparation method of the thin film loaded with gold nanowire Ti3C2Tx layered composite material comprises the following steps:

[0045] 1. Preparation of Ti3C2Tx layered material: Lithium fluoride (1.98 g) was added to a certain amount of hydrochloric acid (20 ml, 9 mol / L) and stirred for 10 minutes until the lithium fluoride was completely dissolved. Titanium aluminum carbide (2 g) was slowly added to the above solution and continued to stir at 35°C for 48 hours. The reaction precipitate was centrifuged and washed with deionized water until the pH value of the supernatant was 6. The precipitate was collected and naturally dried to obtain the Ti3C2Tx layered material, which was dissolved in a certain amount of deionized water to form a black Ti3C2Tx solution (10 mg / ml);

[0046] 2. Preparation of gold nanowire Ti3C2Tx layered composite material: 10 μL of 3-aminopropyltriethoxysilane was added to a 1:1 (volume ratio) mixture of ethanol and deionized water (10 mL) and stirred at room temperature for ten minutes. Sodium citrate solution (100 μL, 14.7 mg / mL) was added to deionized water (20 mL), followed by chloroauric acid solution (19.7 μL, 100 mg / mL). After stirring at room temperature for ten minutes, sodium borohydride solution (600 μL, 3.783 mg / mL) was added to prepare a gold seed solution. The solution was stirred at room temperature for half an hour and allowed to stand for three hours. 1.54 mg of 4-mercaptobenzoic acid was dissolved in 10 mL of ethanol and set aside. 0.035 g of L-ascorbic acid was dissolved in 10 mL of deionized water and set aside. The silicon wafer was soaked in 3-aminopropyltriethoxysilane, and after 1.5 hours, it was washed and dried in ethanol solution and deionized water respectively. The Ti3C2Tx solution (10 μL) obtained in step 1) was dripped onto the treated silicon wafer, left to stand for 10 minutes, and then dried. The dried silicon wafer was soaked in 3-aminopropyltriethoxysilane, and after 1.5 hours, it was washed and dried in ethanol solution and deionized water respectively. The silicon wafer was then placed in the gold seed solution for soaking, and after 1.5 hours, it was washed and dried in ethanol solution and deionized water respectively. A certain amount of 4-mercaptobenzoic acid (200 μL) was dissolved in ethanol (1 mL), and chloroauric acid solution (50 μL, 17 mg / mL) was added and stirred for 10 minutes. The above silicon wafer was added, and then L-ascorbic acid solution (300 μL, 3.5 mg / mL) was added. After standing for 30 minutes, it was washed and dried in ethanol solution and deionized water respectively to obtain a gold nanowire Ti3C2Tx layered composite material.

[0047] 3. Preparation of a gold nanowire-loaded Ti3C2Tx layered composite film: PMMA (0.9 g) was dissolved in a toluene solution (21 ml) and sonicated for 2 hours. A certain amount of the PMMA solution (5 μl) was dropped onto a silicon wafer, cooled to room temperature, and the PMMA film was peeled off the silicon wafer. A certain amount of the gold nanowire-loaded Ti3C2Tx layered composite material (0.01 mg) prepared in step 2) was ultrasonically dispersed in deionized water (100 μl) and coated onto the PMMA film to obtain a gold nanowire-loaded Ti3C2Tx layered composite film suitable for SERS detection.

[0048] The thin film of the gold nanowire-loaded Ti3C2Tx layered composite material prepared in this embodiment consists of two parts: a PMMA film and a gold nanowire-loaded Ti3C2Tx layered composite material. The Ti3C2Tx layer spacing is 100-150 nanometers, the surface has a large number of nanoscale gap structures, and the diameter of the gold nanowire is 5 nanometers.

[0049] The prepared thin film loaded with gold nanowire Ti3C2Tx layered composite material was used for surface enhanced Raman detection of viral proteins such as the novel coronavirus antigen N protein (SARS-CoV-2-N protein), as follows: SARS-CoV-2-N protein (20 μl, 10 -2 mol per liter) was dropped onto a thin film of a gold nanowire Ti3C2Tx layered composite material and dried at room temperature for 2 h. The dried thin film was placed in a Raman spectrometer and its Raman signal was recorded at a laser wavelength of 532 nm.

[0050] Figure 6 The scanning electron microscope photo of the gold nanowire Ti3C2Tx layered composite material prepared in this embodiment is shown. Figure 6 It can be seen that the gold nanowires are shorter and more evenly distributed on the surface of the Ti3C2Tx layered material.

[0051] Figure 7 The surface enhanced Raman test results of the thin film loaded with gold nanowire Ti3C2Tx layered composite material prepared in this embodiment are shown. Figure 7 It can be seen that the film has a good SERS signal enhancement effect at 1000 cm -1 The Raman signal intensity at 1140.

[0052] Although the present invention has been described in detail above using general descriptions and specific embodiments, it will be apparent to those skilled in the art that modifications and improvements may be made based on the present invention. Therefore, such modifications and improvements, which do not depart from the spirit of the present invention, are intended to fall within the scope of protection claimed herein.

Claims

1. A thin film material for surface enhanced Raman detection of viral proteins, characterized in that: The thin film material is a thin film loaded with gold nanowire Ti3C2Tx layered composite material. The thin film consists of two parts: a PMMA film and a Ti3C2Tx layered composite material loaded with gold nanowires. The Ti3C2Tx layer spacing is 100-150 nanometers, the surface has a nanometer-level gap structure, and the diameter of the gold nanowire is 5 nanometers.

2. A method for preparing a thin film material for surface-enhanced Raman detection of viral proteins according to claim 1, characterized in that: The preparation method comprises the following steps: 1) Preparation of Ti3C2Tx layered material: Lithium fluoride was added to a certain amount of hydrochloric acid and stirred for 10 minutes until the lithium fluoride was completely dissolved. Titanium aluminum carbide was slowly added to the above solution and stirring was continued at 35°C for 48 hours. The reaction precipitate was centrifuged and washed with deionized water until the pH value of the supernatant was 6. The precipitate was collected and naturally dried to obtain the Ti3C2Tx layered material, which was dissolved in a certain amount of deionized water to form a black Ti3C2Tx solution. 2) Preparation of gold nanowire Ti3C2Tx layered composite materials: A certain amount of 3-aminopropyltriethoxysilane was added to a mixed solution of ethanol and deionized water in a volume ratio of 1:1, and the mixture was stirred at room temperature for ten minutes; sodium citrate solution was added to deionized water, chloroauric acid solution was added, and the mixture was stirred at room temperature for ten minutes, after which sodium borohydride solution was added to prepare a gold seed solution, which was stirred at room temperature for half an hour and then allowed to stand for three hours; a certain amount of 4-mercaptobenzoic acid was dissolved in ethanol and a certain amount of L-ascorbic acid was dissolved in deionized water; a silicon wafer was soaked in 3-aminopropyltriethoxysilane, and after 1.5 hours, it was washed and dried in ethanol and deionized water respectively. , take the Ti3C2Tx solution prepared in step 1) and drop it on the treated silicon wafer, let it stand for 10 minutes and then dry it; soak the dried silicon wafer in 3-aminopropyltriethoxysilane, and after 1.5 hours, wash it in ethanol solution and deionized water respectively and dry it; then place the silicon wafer in the gold seed solution and soak it, and after 1.5 hours, wash it in ethanol solution and deionized water respectively and dry it; a certain amount of 4-mercaptobenzoic acid is dissolved in ethanol, chloroauric acid solution is added and stirred for 10 minutes, the silicon wafer is added, and then L-ascorbic acid solution is added. After standing for 30 minutes, it is washed in ethanol solution and deionized water respectively and dried to obtain a gold nanowire Ti3C2Tx layered composite material; 3) Preparation of a thin film loaded with a gold nanowire-Ti3C2Tx layered composite material: PMMA was dissolved in a toluene solution and ultrasonicated for 2 hours. A certain amount of the PMMA solution was dropped onto a silicon wafer, cooled at room temperature, and the PMMA film was peeled off from the silicon wafer. A certain amount of the gold nanowire-Ti3C2Tx layered composite material prepared in step 2) was ultrasonically dispersed in deionized water, and coated on the surface of the PMMA film to obtain a thin film loaded with a gold nanowire-Ti3C2Tx layered composite material suitable for SERS detection.

3. The method for preparing a thin film material for surface-enhanced Raman detection of viral proteins according to claim 2, characterized in that: Step 1) is specifically as follows: 1.98 g of lithium fluoride is added to 20 ml of hydrochloric acid with a concentration of 9 mol / L and stirred for 10 minutes until the lithium fluoride is completely dissolved, 2 g of titanium aluminum carbide is slowly added to the above solution, and stirring is continued at 35 ° C for 48 hours; the reactant is centrifuged and washed with deionized water until the pH value of the supernatant is 6, the precipitate is collected, and naturally dried to obtain a Ti3C2Tx layered material, which is dissolved in deionized water to form a black Ti3C2Tx solution with a concentration of 10 mg / mL.

4. The method for preparing a thin film material for surface-enhanced Raman detection of viral proteins according to claim 2, characterized in that: Step 2) Preparation of gold nanowire Ti3C2Tx layered composite material: 10 microliters of 3-aminopropyltriethoxysilane was added to a 10 ml mixed solution of ethanol and deionized water in a volume ratio of 1:1, and stirred at room temperature for ten minutes; 100 microliters of sodium citrate solution with a concentration of 14.7 mg / ml was added to 20 ml of deionized water, 19.7 microliters of chloroauric acid solution with a concentration of 100 mg / ml was added, and stirred at room temperature for ten minutes. After that, 600 microliters of sodium borohydride solution with a concentration of 3.783 mg / ml was added to prepare a gold seed solution, which was stirred at room temperature for half an hour and then allowed to stand for 3 hours; 7.715.4 mg of 4-mercaptobenzoic acid was dissolved in 10 ml of ethanol for use; 0.035 g of L-ascorbic acid was dissolved in 10 ml of deionized water for use; a silicon wafer was soaked in 3-aminopropyltriethoxysilane, After 1.5 hours, the mixture was washed and dried in ethanol solution and deionized water respectively. 10 μL of the Ti3C2Tx solution prepared in step 1) was dropped onto the treated silicon wafer, allowed to stand for 10 minutes, and then dried. The dried silicon wafer was immersed in 3-aminopropyltriethoxysilane, and after 1.5 hours, it was washed and dried in ethanol solution and deionized water respectively. The silicon wafer was then immersed in the gold seed solution, and after 1.5 hours, it was washed and dried in ethanol solution and deionized water respectively. 200 μL of 4-mercaptobenzoic acid was dissolved in 1 ml of ethanol, 50 μL of chloroauric acid solution with a concentration of 17 mg / ml was added, stirred for 10 minutes, the silicon wafer was added, and 300 μL of L-ascorbic acid solution with a concentration of 3.5 mg / ml was added. After standing for 30 minutes, it was washed and dried in ethanol solution and deionized water respectively to obtain a gold nanowire Ti3C2Tx layered composite material.

5. The method for preparing a thin film material for surface-enhanced Raman detection of viral proteins according to claim 2, characterized in that: Step 3) 0.9 g of PMMA was dissolved in 21 ml of toluene solution and ultrasonicated for 2 hours. 5 μl of the PMMA solution was dropped onto a silicon wafer, cooled at room temperature, and the PMMA film was peeled off from the silicon wafer. 0.01 mg of the gold nanowire Ti3C2Tx layered composite material prepared in step 2) was ultrasonically dispersed in 100 μl of deionized water and coated on the surface of the above-mentioned PMMA film to obtain a film loaded with gold nanowire Ti3C2Tx layered composite material that can be used for SERS detection.

6. A method for preparing a thin film material for surface-enhanced Raman detection of viral proteins according to any one of claims 2 to 5, characterized in that: In step 1), the centrifugal speed is 3500 rpm and the centrifugal time is 10 min.

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