SERS (Surface Enhanced Raman Scattering) sensor for detecting flavonoid compounds of scutellaria baicalensis and preparation method thereof

Abstract

The invention discloses an SERS (Surface Enhanced Raman Scattering) sensor for detecting flavonoid compounds of scutellaria baicalensis and a preparation method The method comprises the following steps: step 1, synthesizing N-TiO2 (rutile / anatase) nano particles; step 2, preparing the SERS sensor; and step 3, detecting the flavonoid compounds of scutellaria baicalensis. The semiconductor SERS technology-based scutellaria baicalensis flavonoid direct detection sensor provided by the invention has the advantages of low cost, simplicity and convenience in operation, sensitivity in detection and the like, is particularly suitable for monitoring scutellaria baicalensis components, and has a wide application prospect. The linear range of the flavonoid compound of scutellaria baicalensis is 10 <-3 > M to 5 * 10 <-6 > M, and the detection limit is low.

Description

Technical Field

[0001] The present invention belongs to the field of biomedical detection, and specifically relates to a sensor based on semiconductor surface enhanced Raman scattering technology, which is a surface enhanced Raman scattering spectroscopy (SERS) sensor for directly detecting flavonoid compounds in Scutellaria baicalensis. Background Art

[0002] Scutellaria baicalensis, a commonly used traditional Chinese medicine, has a rich root rich in flavonoids, including baicalin, baicalein, wogonin, and baicalein, which exhibit antioxidant, antibacterial, antiviral, anti-inflammatory, and cardiovascular protective properties. Many factors, such as climate, cultivation conditions, harvesting time, drying, storage, and intentional or accidental adulteration, can contribute to significant variability in the active ingredients. The pharmacological effects of different components vary significantly, necessitating the development of a rapid and sensitive method for detecting flavonoids in Scutellaria baicalensis. Currently, methods for detecting flavonoids in Scutellaria baicalensis include high-performance liquid chromatography, thin-layer chromatography, and liquid chromatography-mass spectrometry. While sensitive, these methods often suffer from complex equipment, cumbersome procedures, and lengthy processing times. Therefore, developing a simple, rapid, and highly sensitive detection method remains a pressing technical challenge.

[0003] SERS technology, with its exceptionally high sensitivity and ability to analyze rich molecular information from biological samples, has been widely applied in the field of biomolecular detection. Currently, a variety of SERS sensors with biomonitoring capabilities have been developed based on this technology and are widely used in biomolecular detection. The development of SERS sensors based on semiconductor materials, particularly those using low-cost and easily synthesized semiconductor composite materials (such as N-TiO2), for the direct detection of scutellaria baicalensis flavonoids would have significant application value. Summary of the Invention

[0004] The present invention aims to provide a sensor based on semiconductor SERS technology for the direct detection of flavonoids from Scutellaria baicalensis. Specifically, it can achieve efficient detection of flavonoids from Scutellaria baicalensis (baicalin, baicalein, wogonin, and wogonin) without the need for sample pretreatment. The present invention only requires the synthesis of TiO2 nanoparticles for the detection of flavonoids from Scutellaria baicalensis. The SERS sensor, constructed from a glass sheet and aluminum foil, is simple to use. The SERS sensor preparation and detection of flavonoids from Scutellaria baicalensis can be completed within 5 minutes. The material binds to the flavonoids to generate a high-intensity SERS signal, enabling sensitive detection of the flavonoids.

[0005] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] A SERS sensor for detecting flavonoids from Scutellaria baicalensis and a preparation method thereof, wherein the preparation steps of the sensor are as follows:

[0007] Step 1. Synthesis of N-TiO2 (rutile / anatase) nanoparticles

[0008] 20 mg of TiN nanoparticles were evenly placed in a magnetic boat in a muffle furnace and calcined at 750°C for 7 h in air. After calcination, the muffle furnace was allowed to cool naturally to room temperature to obtain the N-TiO2 (rutile / anatase) sample.

[0009] Step 2: Preparation of SERS sensor

[0010] A circular aluminum foil with a diameter of 0.66 cm was pasted on the glass slide. 10 μL of TiO2 ethanol dispersion was evenly dropped on the aluminum foil twice and allowed to air dry.

[0011] Step 3: Detection of flavonoids in Scutellaria baicalensis

[0012] 10 μL of the flavonoid compound solution to be tested was added dropwise to the SERS sensor prepared in step 2, and the SERS spectra of different flavonoid compounds of flavonoids were obtained under 785 nm laser excitation.

[0013] The beneficial effects of the present invention compared to the prior art are:

[0014] (1) The present invention develops a SERS sensor based on semiconductor TiO2, which has a simple and efficient operation method;

[0015] (2) The SERS sensor and the process of detecting flavonoids from Scutellaria baicalensis can be completed within 5 minutes, with a short processing time;

[0016] (3) The linear range of Scutellaria baicalensis flavonoids is 10 -3 M~5×10 -6 M, low detection limit and good linear relationship. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a transmission electron microscope image of TiO2 nanoparticles obtained in Example;

[0018] Figure 2 This is a photo of the SERS sensor obtained in Example.

[0019] Figure 3 Schematic diagram of the structure of the SERS sensor obtained in Example;

[0020] Figure 4The SERS signals of four flavonoids from Scutellaria baicalensis (baicalin, baicalein, wogonin and baicalein) obtained by the SERS sensor obtained in the embodiment are compared;

[0021] Figure 5 This is a diagram showing the detection range of baicalin by the SERS sensor obtained in the embodiment;

[0022] Figure 6 This is a diagram showing the detection range of baicalein by the SERS sensor obtained in the embodiment;

[0023] Figure 7 Graph showing the detection range of wogonin by the SERS sensor obtained in Example;

[0024] Figure 8 Graph showing the detection range of wogonin by the SERS sensor obtained in Example; DETAILED DESCRIPTION

[0025] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments, but the experimental conditions and setting parameters therein should not be regarded as limiting the basic technical solution of the present invention. Any modification or equivalent replacement of the technical solution of the present invention that does not depart from the spirit and content of the technical solution of the present invention should be included in the scope of protection of the present invention.

[0026] Step 1. Synthesis of N-TiO2 (rutile / anatase) nanoparticles

[0027] 20 mg of TiN nanoparticles were evenly placed in a magnetic boat in a muffle furnace and calcined at 750°C in air for 7 h at a heating rate of 5°C / min. After calcination, the muffle furnace was allowed to cool naturally to room temperature to obtain the N-TiO2 (rutile / anatase) sample. The resulting N-TiO2 was ground in a mortar for at least 10 minutes and set aside.

[0028] Step 2: Preparation of SERS sensor

[0029] (1) Paste a circular piece of aluminum foil with a diameter of 0.66 cm on the glass slide;

[0030] (2) 2 mg of the synthesized TiO2 nanoparticles were dispersed in 1 ml of anhydrous ethanol and sonicated for 30 min;

[0031] (3) Drop 10 μL of TiO2 ethanol dispersion evenly onto the aluminum foil twice and let it air dry. Repeat the above steps for each SERS sensor preparation.

[0032] Step 3: Detection of flavonoids in Scutellaria baicalensis

[0033] 10 μL of the Scutellaria flavonoid compound solution to be tested was added dropwise twice to the SERS sensor prepared in step 2, and the SERS spectral information of different Scutellaria flavonoid compounds was obtained under 785 nm laser excitation.

[0034] Example:

[0035] A SERS sensor for detecting flavonoids from Scutellaria baicalensis and a preparation method thereof are specifically carried out according to the following steps:

[0036] 1. Synthesis of N-TiO2 (rutile / anatase) nanoparticles

[0037] 20 mg of TiN nanoparticles were evenly placed in a magnetic boat in a muffle furnace and calcined at 750°C in air for 7 h at a heating rate of 5°C / min. After calcination, the muffle furnace was allowed to cool naturally to room temperature to obtain a N-TiO2 (rutile / anatase) sample. The resulting N-TiO2 was then ground in a mortar for at least 10 minutes. Figure 1 This is a transmission electron microscope image of TiO2 nanoparticles. It can be seen that the synthesized N-TiO2 is irregular nano-flake particles.

[0038] 2. Preparation of SERS Sensor

[0039] A circular piece of aluminum foil with a diameter of 0.66 cm was attached to a glass slide. 2 mg of the synthesized TiO2 nanoparticles were dispersed in 1 mL of anhydrous ethanol and sonicated for 30 minutes. 10 μL of the TiO2 ethanol dispersion was evenly dripped onto the aluminum foil twice and allowed to air dry. This procedure was repeated for each SERS sensor fabricated. Figure 2 This is a photo of an actual SERS sensor fabricated. It primarily consists of a TiO2 sensor chip (white area), a carrier (aluminum foil), and a fixture (glass sheet). The glass sheet serves as a fixture, while the aluminum foil is the sample loading area, forming the core of the SERS sensor. Figure 3 A schematic structural diagram of the TiO2 sensor is shown.

[0040] 3. Detection of flavonoids in Scutellaria baicalensis

[0041] Acetone was used as solvent to prepare solutions containing different concentrations of Scutellaria baicalensis flavonoids (10 -3 M~5×10 -6 M), 10 μL of the above solution was added dropwise twice to the SERS sensor prepared in step 2. The solution was allowed to air dry, and SERS spectra were acquired under 785 nm laser excitation. The data acquisition time was 5 s, with one accumulation, and the power was 29 mW. The instrument used was a small Raman spectrometer (Fl785E10W-Pro) purchased from Beijing Zhuoli Hanguang Instrument Co., Ltd. Figure 4SERS spectra of different Scutellaria baicalensis flavonoids (baicalin, baicalein, wogonin and wogonin) detected by SERS sensor. Figure 5 is the detection range of SERS sensor for baicalin, which is 10 -3 M~5×10 -6 M. Figure 6 The detection range of SERS sensor for baicalein is 10 -3 M~5×10 -6 M. Figure 7 is the detection range of SERS sensor for wogonin, which is 10 -3 M~5×10 -6 M. Figure 8 The detection range of SERS sensor for wogonin is 2×10 -5 M~5×10 -6 M.

Claims

1. A SERS sensor for detecting flavonoids from Scutellaria baicalensis and a method for preparing the same, characterized in that: The method steps are as follows: Step 1. Synthesis of N-TiO2 (rutile / anatase) nanoparticles 20 mg of TiN nanoparticles were evenly placed in a magnetic boat in a muffle furnace and calcined at 750°C in air for 7 hours at a heating rate of 5°C / min. After calcination, the muffle furnace was allowed to cool naturally to room temperature to obtain a N-TiO2 (rutile / anatase) sample. The resulting N-TiO2 was then ground in a mortar for at least 10 minutes. Step 2: Preparation of SERS sensor (1) Paste a circular piece of aluminum foil with a diameter of 0.66 cm on the glass slide; (2) 2 mg of the synthesized TiO2 nanoparticles were dispersed in 1 ml of anhydrous ethanol and sonicated for 30 min; (3) 10 μL of TiO2 nanoparticle ethanol dispersion was evenly dropped onto the aluminum foil surface twice and allowed to air dry. The above steps were repeated for each SERS sensor preparation. Step 3: Detection of flavonoids in Scutellaria baicalensis 10 μL of the flavonoid compound solution to be tested was added dropwise twice to the SERS sensor prepared in step 2. SERS spectra of different flavonoid compounds were obtained under 785 nm laser excitation.

2. A SERS sensor for detecting flavonoids from Scutellaria baicalensis and a preparation method thereof according to claim 1, characterized in that: The N-TiO2 nanoparticles obtained in step 1 need to be ground thoroughly.

3. The SERS sensor for detecting flavonoids from Scutellaria baicalensis according to claim 1 and the preparation method thereof, characterized in that: The aluminum foil and glass sheets used in step 2 are purchased from offline stores and are easy to obtain.

4. The SERS sensor for detecting flavonoids from Scutellaria baicalensis and the preparation method thereof according to claim 1, characterized in that: The glass sheet used in step 2 only serves to fix the SERS sensor detection chip and can be replaced by other materials.

5. The SERS sensor for detecting flavonoids from Scutellaria baicalensis and the preparation method thereof according to claim 1, characterized in that: In step 2 (2), the N-TiO2 nanoparticles used need to be fully ultrasonically dispersed in the ethanol solvent.

6. A SERS sensor for detecting flavonoids from Scutellaria baicalensis and a preparation method thereof according to claim 1, characterized in that: In step 3, the scutellaria flavonoids solution to be detected needs to completely immerse the SERS sensor chip.

7. The SERS sensor for detecting flavonoids from Scutellaria baicalensis according to claim 1 and the preparation method thereof, characterized in that: The data acquisition time in the SERS measurement in step 3 is 5 s, 1 accumulation, and the power is 29 mW.

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