Microcapsules, methods for their preparation and use
The microcapsules formed by the self-assembly of hydrophobic nanoparticles solve the reproducibility and sensitivity problems of SERS detection, achieving efficient and low-cost detection, and are suitable for the detection of analytes in multiple fields.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-23
- Publication Date
- 2026-04-14
AI Technical Summary
Existing SERS detection technologies suffer from poor reproducibility and limited sensitivity, and the preparation of composite substrates is difficult and expensive, increasing the time and cost of detection.
Microcapsules were formed by the self-assembly of hydrophobic nanoparticles, with the capsule walls composed of fluorinated organothiol-modified metal nanoparticles. The chambers were filled with analytes. The microcapsules were prepared by a water-oil two-phase emulsification method and used for SERS detection.
It achieves high sensitivity and high reproducibility of SERS detection, simplifies the operation process, reduces costs, and can complete the detection within 10 minutes. It is suitable for molecular detection of analytes in the fields of chemical analysis, environmental monitoring, biomedicine, and food safety.
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Figure CN119951430B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of Raman spectroscopy detection technology, specifically relating to a microcapsule, its preparation method, and its application. Background Technology
[0002] Surface-enhanced Raman scattering (SERS) spectroscopy has attracted widespread attention due to its unique molecular fingerprint information. SERS activity primarily depends on the substrate material properties, nanostructure morphology, or "hot spots" provided by the tips of metallic nanostructures. These "hot spots" are influenced by localized surface plasmon resonances (LSPR), which can provide significant electromagnetic enhancement. SERS is widely used in catalytic process monitoring, bioanalysis, and pollutant detection. However, it often encounters problems such as poor reproducibility and limited sensitivity during analytical detection. Furthermore, the preparation of most SERS composite substrates is currently both difficult and expensive, increasing the time and cost of detection. Therefore, solving the problems of detection sensitivity and reproducibility in SERS detection, simplifying the operation, and enabling it to play a greater role in analytical detection remains a significant challenge. Summary of the Invention
[0003] To overcome the problems existing in the prior art, one objective of this invention is to provide a microcapsule. A second objective is to provide a method for preparing the aforementioned microcapsule. A third objective is to provide applications of the aforementioned microcapsule. A fourth objective is to provide a method for Raman spectroscopy detection of analytes.
[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:
[0005] The first aspect of the present invention provides a microcapsule, the microcapsule being composed of a capsule wall and a chamber, the capsule wall being self-assembled from hydrophobic nanoparticles, and the chamber being filled with an analyte; the hydrophobic nanoparticles are prepared by hydrophobic modification of metal nanoparticles using fluorinated organothiols.
[0006] Preferably, the fluorinated organothiol is 1H,1H,2H,2H-perfluoro-1-decylthiol.
[0007] Preferably, the hydrophobic nanoparticles are prepared by a method comprising the following steps: immersing metal nanoparticles in a fluorinated organothiol solution to perform hydrophobic modification, thereby obtaining the hydrophobic nanoparticles.
[0008] More preferably, the metal nanoparticles are immersed in a hydrophobic treatment solution of isopropanol / n-hexane containing a solution of 1H,1H,2H,2H-perfluoro-1-decylthiol (PFDT), and then washed with a large amount of ethanol.
[0009] More preferably, the concentration of the isopropanol / n-hexane mixed solution containing 1H,1H,2H,2H-perfluoro-1-decylthiol (PFDT) solution is 0.01–1 mmol / L.
[0010] More preferably, the ratio of the metal nanoparticles to 1H,1H,2H,2H-perfluoro-1-decylthiol is (5-30) g:1 mmol.
[0011] More preferably, the soaking time is 5 to 12 hours.
[0012] Preferably, the metal nanoparticles are gold nanoparticles or silver nanoparticles.
[0013] Preferably, the particle size of the metal nanoparticles is 25–325 nm.
[0014] Preferably, the metal nanoparticles are metal nanoparticles modified with benzidine oxide compounds.
[0015] More preferably, the metal nanoparticles modified with benzidine oxide are prepared by a method comprising the following steps: immersing metal nanoparticles in a benzidine oxide compound solution to perform hydrophobic modification, thereby obtaining metal nanoparticles modified with benzidine oxide compound.
[0016] More preferably, the benzidine oxide compound is modified to be 3,3',5,5'-tetramethylbenzidine monooxide.
[0017] More preferably, the metal nanoparticles are immersed in the benzidine oxide compound solution for 7–12 hours.
[0018] More preferably, the 3,3',5,5'-tetramethylbenzidine monooxide is prepared by a method comprising the following steps: 3,3',5,5'-tetramethylbenzidine (TMB) reacts with H2O2 under acidic conditions, using horseradish peroxidase (HRP) as a catalyst, through a solvothermal reaction, to obtain the oxidation product of TMB, 3,3',5,5'-tetramethylbenzidine monooxide (TMB). OX ).
[0019] More preferably, the hydrophobic nanoparticles are prepared by a method comprising the following steps: immersing metal nanoparticles in a solution of 3,3',5,5'-tetramethylbenzidine oxide to modify them, thereby obtaining metal nanoparticles modified with benzidine oxide; immersing the metal nanoparticles modified with benzidine oxide in a solution of 1H,1H,2H,2H-perfluoro-1-decylthiol to perform hydrophobic modification, thereby obtaining the hydrophobic nanoparticles.
[0020] Preferably, the analyte is an organic small molecule or a biological macromolecule.
[0021] More preferably, the organic small molecules include additives and harmful substances.
[0022] More preferably, the additive includes a water-soluble dye.
[0023] More preferably, the harmful substance includes a toxin.
[0024] A second aspect of the present invention provides a method for preparing the microcapsules described in the first aspect, comprising the following steps: dispersing the hydrophobic nanoparticles in an oil phase to obtain an oil phase dispersion; dispersing the analyte in an aqueous phase to obtain an aqueous phase dispersion; mixing the oil phase dispersion and the aqueous phase dispersion, and emulsifying them to obtain the microcapsules.
[0025] Preferably, the oil phase is a long-chain alkane.
[0026] More preferably, the oil phase is halogen-substituted or unsubstituted C8-C. 18 Straight-chain alkanes.
[0027] More preferably, the oil phase is selected from one of chloroform, carbon tetrachloride, bromoethane, dichloromethane, pentamethylheptane, decane, hexane, and hexadecane.
[0028] Preferably, the mass-to-volume ratio of hydrophobic nanoparticles to the oil phase in the oil dispersion is (1-100) mg:1 mL;
[0029] Preferably, the volume ratio of the oil phase dispersion to the aqueous phase dispersion is (1.5 to 200):1.
[0030] Preferably, the mixing method involves adding the aqueous dispersion dropwise to the oil dispersion.
[0031] Preferably, the emulsification is performed under ultrasonic conditions.
[0032] More preferably, the frequency of the ultrasound is 30–100 kHz; the ultrasound duration is 1–15 min. Even more preferably, the ultrasound duration is 1–5 min.
[0033] The third aspect of the present invention provides the application of the microcapsules described in the first aspect in mid-Raman spectroscopy detection.
[0034] Preferably, the microcapsules are used in SERS detection of chemical analysis, environmental monitoring, biomedicine, or food safety analyte molecules.
[0035] A fourth aspect of the present invention provides a method for detecting an analyte using Raman spectroscopy, wherein the analyte is prepared into microcapsules as described in the first aspect, or the analyte is prepared into microcapsules according to the preparation method of the second aspect, and SERS spectral acquisition is performed on the microcapsules.
[0036] Preferably, a method for detecting analytes using Raman spectroscopy includes the following steps:
[0037] Metal nanoparticles were modified by immersing them in a solution of 3,3',5,5'-tetramethylbenzidine monoxide to obtain metal nanoparticles modified with benzidine oxide; the metal nanoparticles modified with benzidine oxide were then modified by immersing them in a solution of 1H,1H,2H,2H-perfluoro-1-decylthiol to obtain the hydrophobic nanoparticles, which were then dispersed in an oil phase to obtain an oil phase dispersion.
[0038] The toxin antigen was fixed, and different concentrations of toxin solutions and primary antibodies were added. After washing, alkaline phosphatase-labeled secondary antibodies were added. After the reaction was completed, L-ascorbic acid-2-phosphate trisodium salt (AAP) was added, and the above reaction solution was further mixed with tris(2-carboxyethyl)phosphine (TCEP) to form an aqueous dispersion.
[0039] The above aqueous dispersion was dropped into the oil dispersion, and microcapsules were prepared according to the conditions in the second aspect of the present invention. The microcapsules were then subjected to SERS spectral acquisition.
[0040] More preferably, the toxin in the toxin solution is T-2 toxin.
[0041] The beneficial effects of this invention are:
[0042] This invention provides a microcapsule comprising a capsule wall and a chamber. The capsule wall is self-assembled from hydrophobic nanoparticles, and the chamber is filled with analytes, effectively binding the SERS substrate and target molecules together. The microcapsule exhibits high hotspot density in all spatial planes and strong tolerance to laser focus misalignment, making it a promising candidate for constructing highly reproducible SERS sensing platforms. Furthermore, microcapsules offer significant advantages in encapsulating active substances and have already been applied in drug delivery, two-phase catalysis, and chemical reaction monitoring. In this invention, the hydrophobic nanoparticles in the microcapsule are prepared by hydrophobic modification of metal nanoparticles with fluorinated organothiols. The constructed microcapsule targets highly Raman-active molecules, achieving integrated recognition and enrichment with label-free SERS detection to improve detection sensitivity. This invention offers high sensitivity and high reproducibility, is simple to operate, and inexpensive; the entire detection process can be completed within 10 minutes, effectively solving the problems of poor reproducibility and limited sensitivity in SERS detection.
[0043] Specifically, compared with the prior art, the present invention has the following advantages:
[0044] (1) The microcapsules of the present invention can also be used for SEBS detection of compounds with low content and small Raman scattering cross section. The hydrophobic nanoparticles are prepared by hydrophobic modification of metal nanoparticles modified with fluorinated organothiols to benzidine oxide compounds. The prepared microcapsules can also be used to achieve ultrasensitive detection of target substances by integrating recognition enrichment and SERS sensing detection.
[0045] (2) The microcapsules of this invention can tightly encapsulate the analytes inside, thereby avoiding sample leakage and mutual interference between samples. Furthermore, the microcapsules have a reasonable structural design, and their size and structure meet the application requirements of SERS detection. From an application perspective, the microcapsules can not only construct methods integrating identification and enrichment with label-free SERS detection, but also methods integrating identification and enrichment with SERS sensing detection. In addition, the microcapsules of this invention have negligible SERS background interference and stable size, and can enrich samples, thus exhibiting excellent SERS signal reproducibility and detection sensitivity.
[0046] (3) The microcapsule preparation method of the present invention is formed by water-oil two-phase emulsification and self-assembly at the interface. Not only is the preparation method simple, but it can also make microcapsules for water-soluble analytes in the fields of chemical analysis, environmental monitoring, biomedicine or food safety, and the applicable analytes are wide-ranging. Attached Figure Description
[0047] Figure 1 A flowchart of the method for preparing microcapsules (A) and physical images (B) and SEM images (C) of microcapsules prepared by various oil phases;
[0048] Figure 2 SERS spectra of microcapsules encapsulated with MB prepared for different silver / water ratios;
[0049] Figure 3 The repeatability (A) and reproducibility test results (B) of the microcapsules prepared in Example 1 are shown.
[0050] Figure 4 The SERS spectrum (A) and standard curve (B) are shown for the identification, enrichment, and label-free detection of MB by microcapsules in Example 1.
[0051] Figure 5 The SERS spectrum (A) and working curve (B) of the microcapsules used in Example 2 for the identification, enrichment and SERS sensing detection of T-2 toxin;
[0052] Figure 6 The SERS spectra of the microcapsules used in Example 2 for the identification, enrichment, and SERS-sensing detection of T-2 toxin in peanuts (A) and corn (B) are shown. Detailed Implementation
[0053] The present invention will be further described in detail below through specific embodiments. Unless otherwise specified, the raw materials used in the following embodiments can be obtained from conventional commercial channels or prepared and isolated through simple synthesis; unless otherwise specified, the processes employed are conventional processes in the art.
[0054] Example 1
[0055] This embodiment provides a method for preparing microcapsules containing methylene blue (MB) as the analyte. A schematic diagram of the preparation process is shown below. Figure 1 As shown in A, the specific steps are as follows:
[0056] (1) Preparation of silver nanoparticles: AgNO3 (0.125 g) and PVP (0.625 g) were dissolved in 50 mL of ethylene glycol. The mixture was then transferred to an oil bath and heated to 130 °C with vigorous stirring. After stirring was stopped, the mixture was kept at 130 °C for 1 h. Finally, the mixture was purified by washing with a large amount of acetone and ethanol to obtain 100 mg of silver nanoparticles.
[0057] (2) Preparation of hydrophobic silver nanoparticles: 20 mg of purified silver nanoparticles were soaked in 10 mL of isopropanol / n-hexane solution (1:1, v / v) containing 0.1 mmol / L PFDT at room temperature for 6 h. Then, they were washed with a large amount of ethanol and decane, and then dispersed in 1.0 mL of decane to obtain hydrophobic silver nanoparticles (PFDT-AgNPs) with a concentration of 20 mg / mL.
[0058] (3) Microcapsule preparation: Microcapsules were prepared by manipulating the mass of PFDT-AgNPs and the volume of water (silver / water ratio) during emulsification. Taking the preparation of microcapsules with a silver / water ratio of 70 mg / mL as an example, 14 μL of 20 mg / mL PFDT-AgNPs was diluted 10 times with decane and sonicated to obtain a brown transparent suspension. Subsequently, 4.0 μL of MB (10...) at different concentrations was added to the suspension. -5 mol / L, 10 -6 mol / L, 10 -7 mol / L, 10 -8 mol / L, 10 -9 mol / L and 10 -10 Microcapsules were obtained by ultrasonic emulsification of a mol / L aqueous solution at an ultrasonic frequency of 30–100 kHz for 1–5 min.
[0059] As a comparison, 4 μL, 8 μL, 12 μL, and 16 μL of 20 mg / mL PFDT-AgNPs were diluted 10-fold with decane and sonicated to obtain brown transparent suspensions. Subsequently, 4.0 μL of 10-decane was added to each suspension. -7Microcapsules with silver / water ratios of 20 mg / mL, 40 mg / mL, 60 mg / mL and 80 mg / mL were obtained by using MB solution of mol / L.
[0060] It should be noted that microcapsules can be prepared using any two immiscible phases, such as mixing an aqueous phase with several common oil phases. These oil phases include chloroform, carbon tetrachloride, bromoethane, dichloromethane, pentamethylheptane, decane, hexane, and hexadecane. If the oil phase is lighter than water (e.g., decane, pentamethylheptane, hexane, and hexadecane), the microcapsules will sink to the bottom of the container. Figure 1 (B1-B4), and the corresponding SEM results of the prepared microcapsules are as follows: Figure 1 Medium B5-B8. Conversely, if the oil phase is heavier than water (e.g., chloroform, carbon tetrachloride, bromoethane, and dichloromethane), the microcapsules will float on the surface of the oil phase. Figure 1 (C1-C4), and the corresponding SEM results of the prepared microcapsules are as follows: Figure 1 The SEM results of C5-C8 phases also indicate that the method for preparing microcapsules is universal, and any two immiscible phases can be used to prepare microcapsules.
[0061] Example 2
[0062] This embodiment provides a method for preparing microcapsules containing T-2 toxin as the analyte, and the specific steps are as follows:
[0063] (1) Under acidic conditions with pH 3.0–6.0, horseradish peroxidase (HRP) was used as a catalyst to react TMB with H2O2 in a solvothermal reaction at 25–50 °C for 0.5–2 h to obtain the oxidation product TMB. OX The molar ratio of TMB, H2O2 and HRP is (30-110):(2-8):1.
[0064] (2) 20 mg of purified silver nanoparticles were dispersed in 20 mL of isopropanol / hexane mixed solution (1:1, v:v). Then, 1 mL of TMB was added to the above solution. OX A 5 mmol / L solution was prepared and magnetically stirred for 10 h, followed by centrifugation and discarding of the supernatant to obtain Ag@TMB. OX . Ag@TMB OX The PFDT was dispersed in 20 mL of a mixed solution of isopropanol / hexane containing 0.1 mmol / L PFDT and stirred for 10 h. Finally, the PFDT-Ag-TMB was obtained by washing with a large amount of ethanol and decane. OX The suspension was dispersed in 1.0 mL of decane to obtain PFDT-Ag@TMB with a concentration of 20 mg / mL. OX .
[0065] (3) Add 100 μL of BSA-T2 (5 μg / mL) to a 96-well plate and incubate overnight at 4°C. Then, add BSA (1%, 250 μL) and incubate for 1 h at 37°C. Next, add 25 μL of T-2 toxin standard and 25 μL of toxin primary antibody (Ab1, 5 μg / mL) and incubate for 1 h at 37°C. Then, add 50 μL of alkaline phosphatase-labeled toxin secondary antibody ALP-Ab2 (0.5 μg / mL) to the wells and react for 1 h at 37°C. After each of the above steps, wash the wells carefully three times with 1×PBST buffer. Then, add 100 μL of L-ascorbic acid-2-phosphate trisodium salt (AAP, 1.0 mmol / L) to the wells and react for 1 h at 37°C to obtain the catalytic product ascorbic acid (AA).
[0066] (4) To obtain microcapsules, the catalytic product AA from step (3) was mixed with 100 μL of TCEP (thiol reducing agent, 1.2 mmol / L), and 4 μL of the above mixed aqueous solution was transferred to 200 μL of decane solution. Then, 14 μL of LPFDT-Ag@TMB was added. OX (20 mg / mL) was ultrasonically emulsified to form microcapsules at a frequency of 30–100 kHz for 1–5 min to obtain microcapsules encapsulating catalytic products (AA) and TCEP. The microcapsules were then allowed to stand for 9 min to allow AA and TCEP to react with the benzidine oxide compound on the surface of the capsules.
[0067] Example 3
[0068] This embodiment provides an application of microcapsules containing T-2 toxin as an analyte in the field of food safety. The specific steps are as follows:
[0069] (1) Experimental groups: ① 120 μg / kg T-2 toxin standard; ② crushed peanut sample; ③ 120 μg / kg T-2 toxin spiked with 0.5 g crushed corn sample; ④ 320 μg / kg T-2 toxin standard; ⑤ crushed corn sample; ⑥ 320 μg / kg T-2 toxin spiked with 0.5 g crushed peanut sample.
[0070] Samples from experimental groups ②, ③, ⑤, and ⑥ were added to 20 mL of methanol / water extraction solvent (8:2, v / v), vortexed for 20 min, and then filtered through glass fiber filter paper.
[0071] (2) 100 μL of BSA-T2 (5 μg / mL) was added to a 96-well plate and incubated overnight at 4 °C. Then, BSA (1%, 250 μL) was added and incubated for 1 h at 37 °C. Subsequently, 25 μL of the above experimental groups ①②③④⑤⑥ and 25 μL of the toxin primary antibody (Ab1, 5 μg / mL) were added to the wells and incubated for 1 h at 37 °C. Then, 50 μL of alkaline phosphatase-labeled toxin secondary antibody ALP-Ab2 (0.5 μg / mL) was introduced into the wells and reacted at 37 °C for 1 h. After each of the above steps, the wells were carefully washed three times with 1×PBST buffer. Subsequently, 100 μL of L-ascorbic acid-2-phosphate trisodium salt (AAP, 1.0 mmol / L) was added to the wells and reacted at 37 °C for 1 h to obtain the catalytic product ascorbic acid (AA). The resulting catalytic product AA was then mixed with 100 μL of TCEP (1.2 mmol / L), and 4 μL of the above aqueous mixture was transferred to 200 μL of decane solution. Then, 14 μL of LPFDT-Ag@TMB was added. OX (20 mg / mL), ultrasonically emulsified to form microcapsules.
[0072] Experimental Analysis
[0073] 1. SERS detection method
[0074] Subsequently, 5.0 μL of microcapsules immersed in decane were dropped onto a 3×3 mm silicon wafer. A laser was focused onto the microcapsules. Surface-enhanced Raman spectroscopy parameters were set as follows: 5x objective lens, 0.1% filter (laser power 100 μW), grating line density 600 gr / mm, accumulation time 500 ms, excitation wavelength 532 nm, and wavelength at 200 cm⁻¹. -1 -1800cm -1 Collect data within the specified range.
[0075] 2. Test Results
[0076] (1) 10 -7 SERS results of encapsulating mol / L MB in microcapsules are as follows: Figure 2 As shown, line 1 shows the SERS spectrum of MB after mechanically mixing silver nanoparticles (with the same mass ratio) with MB and dropping them onto a silicon wafer to form coffee rings. Lines 2-6 show the SERS spectra of MB prepared with microcapsules at silver / water ratios of 20, 40, 60, 70, and 80 mg / mL, respectively. Clearly, MB is enriched during microcapsule formation; the concentration increases with increasing silver / water ratio, reaching 1633 cm⁻¹. -1 The signal at the location also increased accordingly. The microcapsules exhibited the best confined enrichment effect when the silver-to-water ratio was 70 mg / mL. The microcapsules have been successfully prepared.
[0077] The repeatability and reproducibility of the microcapsules in Example 1 were tested, and the specific test results are as follows: Figure 3 As shown, where, Figure 3 A is the SERS test response diagram of the microcapsules in 15 batches of Example 1, with a relative deviation of 4.8%; Figure 3 B is the SERS test response graph for the microcapsule test in Example 1 after 15 runs, with a relative deviation of 6.9%. From... Figure 3 It can be seen that the microcapsule test of MB using the present invention has good repeatability and reproducibility.
[0078] (2) SERS detection was performed on aqueous solutions of MB at each concentration in Example 1. The average intensity was obtained by performing the detection in 3 experiments.
[0079] Figure 4 A is the SERS spectrum obtained from the detection of MB. Figure 4 B is the standard curve for SERS detection of MB, with an MB concentration of 10. - 5 mol / L, 10 -6 mol / L, 10 -7 mol / L, 10 -8 mol / L, 10 -9 mol / L and 10 -10 The concentration of mol / L indicates that microcapsules can be used to construct a method that integrates recognition and enrichment with label-free SERS detection.
[0080] 3. Figure 5 A is the SERS spectrum obtained for T-2 toxin detection based on microcapsules, which integrates recognition, enrichment, and SERS sensing. (1609 cm⁻¹) -1 The SERS intensity at the location indicates that the signal gradually increases with increasing T-2 toxin concentration. Figure 5 B showed that the logarithm of T-2 toxin concentration had a good linear relationship with SERS intensity in the range of 0.005-40.0 μg / L. The linear equation was I = 2618.61 log C T-2 +8506.31 (R=0.9993), the detection limit for T-2 toxin is 1.64 ng / L.
[0081] 4. Figure 6 This is a SERS spectrum of a microcapsule-based method for detecting T-2 toxin in food, integrating recognition, enrichment, and SERS sensing. Figure 6 Curves 1-3 in (A) represent experimental groups ①②③, respectively. Figure 6 Curves 1-3 in (B) are ④⑤⑥ respectively. (From...) Figure 6This indicates that the food samples in experimental groups ② and ⑤ are positive samples, containing T-2 toxin. The microcapsules prepared in this invention can detect T-2 toxin in food using an integrated method that combines recognition enrichment with SERS sensing detection.
[0082] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.
Claims
1. A microcapsule, characterized in that, The microcapsule consists of a capsule wall and a chamber. The capsule wall is self-assembled from hydrophobic nanoparticles, and the chamber is filled with the analyte. The hydrophobic nanoparticles are prepared by hydrophobic modification of metal nanoparticles with fluorinated organothiols. The fluorinated organothiol is 1H,1H,2H,2H-perfluoro-1-decylthiol; the metal nanoparticles are metal nanoparticles modified with benzidine oxide compounds. The hydrophobic nanoparticles are prepared by a method comprising the following steps: immersing metal nanoparticles in a solution of 3,3',5,5'-tetramethylbenzidine oxide to modify them, thereby obtaining metal nanoparticles modified with benzidine oxide; immersing the metal nanoparticles modified with benzidine oxide in a solution of 1H,1H,2H,2H-perfluoro-1-decylthiol to perform hydrophobic modification, thereby obtaining the hydrophobic nanoparticles.
2. The microcapsule according to claim 1, characterized in that, The metal nanoparticles are gold nanoparticles or silver nanoparticles. And / or, the particle size of the metal nanoparticles is 25~325 nm.
3. The microcapsule according to claim 1, characterized in that, The analytes are small organic molecules or biological macromolecules.
4. The method for preparing the microcapsules according to any one of claims 1 to 3, characterized in that, The process includes the following steps: dispersing the hydrophobic nanoparticles in an oil phase to obtain an oil phase dispersion; dispersing the analyte in an aqueous phase to obtain an aqueous phase dispersion; mixing the oil phase dispersion and the aqueous phase dispersion, and emulsifying them to obtain the microcapsules.
5. The method for preparing microcapsules according to claim 4, characterized in that, The oil phase is a long-chain alkane; And / or, the mass-to-volume ratio of the hydrophobic nanoparticles in the oil phase dispersion to the oil phase is (1~100) mg:1 mL; And / or, the volume ratio of the oil phase dispersion to the aqueous phase dispersion is (1.5~200):
1.
6. The method for preparing microcapsules according to claim 4, characterized in that, The emulsification was performed under ultrasonic conditions.
7. The application of the microcapsules according to any one of claims 1 to 3 in Raman spectroscopy detection.
8. A method for detecting analytes using Raman spectroscopy, characterized in that, The analyte is prepared into microcapsules as described in any one of claims 1 to 3, or the analyte is prepared into microcapsules according to the preparation method described in any one of claims 4 to 6, and SERS spectroscopy is performed on the microcapsules.