Preparation method and application of rapid and controllable large-scale gold nanorod silicon-coated material

Abstract

The invention discloses a preparation method and application of a rapid and controllable large-batch gold nanorod silicon-coated material, and belongs to the technical field of biomedical materials. High-efficiency preparation is realized through combination of low-temperature freezing and an ultrasonic process, and the preparation method comprises the following specific steps: firstly, preparing an AuNR solution through chemical reduction by adopting a seed-mediated growth method; then modifying AuNR by using SH-PEG5k-X, and carrying out freezing-unfreezing redissolution to form AuNR (at) PEG (Polyethylene Glycol); finally, ammonia water-isopropanol and a TEOS-isopropanol solution are sequentially added under ultrasonic assistance, uniform silicon coating is achieved, and PEG-AuNR coated SiO2, namely the gold nanorod silicon-coated material, is prepared. According to the method, dispersion and mixing of reactants are promoted through the ultrasonic cavitation effect, 10 mg-grade preparation can be completed within 3 hours, the product concentration reaches 3.18 * 10 <-6 > mol / mL, the coating layer is high in uniformity, the obtained material has application potential in the fields of pathogen detection and the like, and the bottleneck problems that a traditional method is low in speed, poor in product consistency and the like are solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of biomedical materials, and particularly relates to a method for preparing a silicon-coated gold nanorod material in large quantities with rapid controllability and its application. Background Art

[0002] The surface plasmon resonance (SPR) wavelength of gold nanorods can vary with the aspect ratio of the gold nanorods, and can be continuously adjusted from the visible light range (550 nm) to the near-infrared light range (1550 nm). The surface plasmon resonance of gold nanorods is an optical phenomenon based on the collective oscillation of free electrons on the metal surface, which can convert light energy into heat energy, and has broad application prospects in the fields of photothermal therapy, bioimaging, and biosensors. However, gold nanorods have poor stability in the physiological environment and are prone to aggregation, which limits their practical applications. Silicon dioxide has good biocompatibility, chemical stability, and modifiability, and is often used to coat gold nanorods to prevent their aggregation, oxidation, or structural deformation during photothermal cycling, which can enhance biocompatibility in biomedical applications and can also be used as a carrier to load drugs to achieve multifunctional integrated diagnosis and treatment.

[0003] The commonly used method for preparing silicon-coated gold nanorod materials in the laboratory is as follows: (1) Stöber method: Depositing SiO2 on the surface of AuNRs by hydrolysis of a silane precursor such as tetraethoxysilane (TEOS), but it is prone to cause uneven SiO2 shell layers (such as local over-thickness or pore defects), affecting optical properties, and it is difficult to accurately control the layer thickness, and usually requires empirical adjustment of the reaction time or precursor concentration; (2) LBL layer-by-layer coating method: This scheme is based on the intermediate adsorption of a polyvinylpyrrolidone (PVP) layer for coating colloidal nanoparticles with silica. Screening and coating silica by layer-by-layer (LBL) adsorption of charged polyelectrolytes. Although the reaction repeatability is good and efficient, due to the cumbersome steps, the actual reaction preparation cycle is long; (3) Surfactant-assisted method: Using templates such as cetyltrimethylammonium bromide (CTAB) to guide the growth of SiO2 and optimize the shell thickness, but CTAB surfactants may remain in the SiO2 shell layer, resulting in cytotoxicity.

[0004] Currently, the process of coating gold nanorods with silicon all has problems such as low repeatability, long reaction time (≥12 h), and low batch yield of silicon coating (small batches in the laboratory), which restricts the application of the technology of coating gold nanorods with silicon. Therefore, there is an urgent need to propose a method for silicon dioxide coating that can achieve rapid, uniform, and controllable coating to prepare silicon-coated gold nanorod materials with high consistency. Summary of the Invention

[0005] In order to overcome the disadvantages of poor repeatability, long reaction time and low yield in the preparation process of gold nanorods in the above-mentioned existing technologies, the purpose of the present invention is to provide a method for preparing a silicon-coated gold nanorod material in large quantities quickly and controllably, and by combining low-temperature freezing and ultrasonic processes, the preparation efficiency of the silicon-coated gold nanorod material is improved.

[0006] In order to achieve the above purpose, the present invention is implemented by adopting the following technical solutions: The first object of the present invention is to propose a method for preparing a silicon-coated gold nanorod material quickly and controllably, including the following steps: S1. Take CTAB to prepare an AuNR seed solution and a growth solution, mix the AuNR seed solution and the growth solution, and take the precipitate to dissolve to obtain a gold nanorod solution; S2. Add SH-PEG 5k -X solution to the gold nanorod solution, freeze, thaw and redissolve, then centrifuge, wash and dissolve to obtain an AuNR@PEG solution; S3. Add the AuNR@PEG solution to water for ultrasonic dispersion, and sequentially add an ammonia-isopropanol solution and a TEOS-isopropanol solution, and react to obtain PEG-AuNR@SiO2, that is, the silicon-coated gold nanorod material.

[0007] Preferably, in the step S2, the freezing temperature is -80~ -20°C, and the freezing time is 5~30 min.

[0008] Preferably, in the step S2, the volume ratio of the gold nanorod solution to the SH-PEG 5k -X solution is 20:1, where the concentration of the gold nanorod solution is 5 OD, and the concentration of SH-PEG 5k -X is 100 mM.

[0009] Preferably, in S3, the AuNR@PEG solution is mixed with water and ultrasonicated. After the AuNR@PEG solution is monodispersed, the ammonia-isopropanol solution is first added under the ultrasonic condition of 300~400 W power, and then the TEOS-isopropanol solution is added in batches.

[0010] Further preferably, in S3, the pH value of the mixed solution is adjusted to 10~11 by adding the ammonia-isopropanol solution.

[0011] Further preferably, before the ultrasonic treatment, the volume ratio of the AuNR@PEG solution, water, and the TEOS-isopropanol solution is 30:136:40.

[0012] Further preferably, before the ultrasonic treatment, the concentration of the AuNR@PEG solution (measured by a spectrophotometer) is 15 - 60 OD, and the concentration of the TEOS-isopropanol solution is 0.97 - 3.88 v%.

[0013] Preferably, in the step S1, the preparation process of the AuNR seed solution specifically includes: adding an ice-bathed NaBH4 solution to a mixed solution of a CTAB solution and a HAuCl4 solution to form a mixed solution, and vigorously stirring the mixed solution until the mixed solution turns brown, thus obtaining the AuNR seed solution.

[0014] Preferably, in the step S1, the growth solution is specifically formed by mixing a HAuCl4 solution, a CTAB solution, a silver nitrate solution, and an ascorbic acid solution.

[0015] The second object of the present invention is to disclose the application of the gold nanorod-coated silicon material prepared by the above-mentioned rapid and controllable gold nanorod-coated silicon material preparation method in the field of pathogen detection.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The rapid and controllable gold nanorod-coated silicon material preparation method proposed by the present invention combines a cryogenic freezing technique and utilizes the stable gold-sulfur covalent bond formed between the mercapto molecule SH-PEG and gold nanoparticles to complete the preparation of AuNR@PEG. Among them, SH-PEG 5k -X is positively charged, providing positive charges for coating the silicon layer, which is beneficial to electrostatic adsorption with the negatively charged TEOS precursor to improve its stability. The present invention introduces ultrasound during the dilution process of AuNR@PEG. Compared with a conventional magnetic stirrer, ultrasound can generate a cavitation effect in the solution, forming tiny bubbles that quickly burst, generating a strong local impact force, which can promote the uniform mixing of reactants in the solution, thereby improving the uniformity of the coating layer. This is crucial for ensuring the uniformity of the silica coating layer on the surface of gold nanorods; the cavitation effect generated by ultrasound can increase the contact area and reaction activity between reactants, thereby accelerating the reaction rate, shortening the time required for the coating process, and improving production efficiency; the vibration effect of ultrasound can effectively disperse nanoparticles, reducing their aggregation, which helps to improve the dispersibility and stability of gold nanorods in the solution. Through experiments, it is proved that the present invention expands the reaction system based on the freezing method and the ultrasound method, and can complete the preparation of 10 mg (weighed after freeze-drying treatment) of gold nanorod-coated silicon within 3 hours. At the same time, the concentration of the gold nanorod-coated silicon material product measured by an inductively coupled plasma mass spectrometer is 3.18x10 -6 mol / mL, indicating that the reaction for preparing the gold nanorod-coated silicon material of the present invention has a high yield. Description of the Drawings

[0017] Figure 1PEG-AuNR@SiO2 prepared from SH-PEG-X with different functional groups in the embodiments of the present invention. (a) TEM images of the prepared AuNRs and AuNR@SiO2 synthesized with SH-PEGs having different functional groups, (b) UV images of the prepared AuNRs and AuNR@SiO2 synthesized with SH-PEGs having different functional groups, (c) statistical chart of the silica layer thickness of the prepared AuNRs and AuNR@SiO2 synthesized with SH-PEGs having different functional groups, (d) zeta potential images of the prepared AuNRs and AuNR@SiO2 synthesized with SH-PEGs having different functional groups.

[0018] Figure 2 PEG-AuNR@SiO2 prepared by the PEG-mediated rapid freezing method under different conditions in the embodiments of the present invention. (a) Physical images of freezing at -20°C for different times, (b) zeta potential images of freezing at -20°C for different times, (c) UV images of freezing at -20°C for different times, (d) physical images of freezing at -80°C for different times, (e) zeta potential images of freezing at -80°C for different times, (f) UV images of freezing at -80°C for different times.

[0019] Figure 3 Au-S bonding test results within 15 minutes by the PEG-mediated rapid freezing method in the embodiments of the present invention. It is the infrared spectrum of AuNRs and SH-PEG-NH2 after freezing.

[0020] Figure 4 Yield results of the embodiments and comparative examples of the present invention. (a) Reagent bottle after the reaction using the stirring method, (b) TEM image of AuNR@SiO2 obtained using the stirring method, (c) physical image of AuNR@SiO2 obtained using the stirring method, (d) reagent bottle after the reaction using the ultrasonic method, (e) TEM image of AuNR@SiO2 obtained using the ultrasonic method, (f) physical image of AuNR@SiO2 obtained using the ultrasonic method.

[0021] Figure 5 Silica layer thickness under different TEOS volume conditions in the embodiments of the present invention. (a) TEM images under different TEOS volume conditions, (b) UV images under different TEOS volume conditions, (c) data chart of the silica layer thickness under different TEOS volume conditions.

[0022] Figure 6 Silica layer thickness under different reaction time conditions in the embodiments of the present invention. (a) TEM images under different reaction time conditions, (b) UV images under different reaction time conditions, (c) data chart of the silica layer thickness under different reaction time conditions.

[0023] Figure 7This is the TEM characterization of PEG-AuNR@SiO2 prepared by expanding the reaction system under cryo-ultrasound conditions in the embodiments of the present invention. Detailed implementation manners

[0024] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0025] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily need to be used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present invention described here can be implemented in an order other than those illustrated or described here. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0026] The present invention will be further described in detail below in conjunction with the accompanying drawings: The present invention discloses a method for preparing a large quantity of gold-silica core-shell nanomaterials quickly and controllably, comprising the following steps: (1) Preparation of gold nanorods; (2) Using Au-S bonding, quickly replacing CTAB by polyethylene glycol (PEG)-mediated freezing method; (3) Using Si-O bonding, guiding the growth of SiO2 under ultrasonic environment, regulating the amount of TEOS and time factors, and optimizing the shell thickness; In some embodiments of the present invention, by regulating and optimizing the reagent ratios in (2) and (3), the production yield of single-time PEG-AuNR@SiO2 can be increased.

[0027] In some embodiments of the present invention, the preparation process specifically comprises the following steps: S1, preparing gold nanorods, taking CTAB to prepare AuNR seed solution and growth solution, mixing the AuNR seed solution and the growth solution, and taking the precipitate to dissolve to obtain a gold nanorod solution; S2. Using Au-S bonding, rapidly replace CTAB by the PEG-mediated freezing method: Add SH-PEG 5k -X solution to the gold nanorod solution, freeze, thaw and redissolve, then centrifuge, wash and dissolve to obtain the AuNR@PEG solution; S3. Using Si-O bonding, under ultrasonic environment, guide the growth of SiO2: Add the AuNR@PEG solution to water and ultrasonically disperse it, then sequentially add ammonia-isopropanol solution and TEOS-isopropanol solution, and react to obtain PEG-AuNR@SiO2.

[0028] In the embodiments of the present invention, the ammonia-isopropanol solution refers to the solution obtained by dissolving ammonia in isopropanol as the solvent, the TEOS-isopropanol solution refers to the solution obtained by dissolving TEOS in isopropanol as the solvent, and TEOS refers to tetraethyl orthosilicate.

[0029] In the embodiments of the present invention, AuNR refers to Gold Nanorods.

[0030] In the embodiments of the present invention, AuNR@PEG refers to gold nanorods coated with polyethylene glycol.

[0031] In the embodiments of the present invention, SH-PEG 5k -X solution refers to the solution obtained by dissolving SH-PEG 5k -X in water. In SH-PEG 5k -X, PEG 5k is PEG with a molecular weight of 5000 g / mol, -SH is a mercapto group, and -X is different functionalized end groups. The SH-PEG 5k -X used in the embodiments of the present invention are all commercially available products without further treatment, and the manufacturer is Chongqing Yusai Medical Technology Co., Ltd.

[0032] In some preferred embodiments, in step S2, the freezing temperature is -80~-20°C, for example, it can be, but is not limited to, -80°C, -60°C, -40°C, -20°C, and the freezing time is 5~30 min, for example, it can be, but is not limited to, 5 min, 10 min, 15 min, 20 min, 25 min, 30 min.

[0033] In some preferred embodiments, in step S2, the volume ratio of the gold nanorod solution to the SH-PEG 5k -X solution is 20:1, where the concentration of the gold nanorod solution is 5 OD and the concentration of the SH-PEG 5k -X solution is 0.1 mol / L.

[0034] In some preferred embodiments, in step S3, after the AuNR@PEG solution is mixed with water and ultrasonicated to make the AuNR@PEG solution monodisperse, an ammonia-isopropanol solution is first added under ultrasonic conditions with a power of 300-400 W to adjust the pH value of the mixed solution to 10-11. For example, it can be, but is not limited to, 10, 10.2, 10.4, 10.5, 10.8, or 11, preferably 10.8. Then, the TEOS-isopropanol solution is added in portions.

[0035] In some preferred embodiments, the ammonia-isopropanol solution, the TEOS-isopropanol solution, and the AuNR@PEG solution are ultrasonically mixed at a power of 300-400 W, preferably 360 W, and the ultrasonic mixing time is 1.5-2.5 h, preferably 2 h.

[0036] In some preferred embodiments, in S3, the volume ratio of the AuNR@PEG solution, water, and TEOS-isopropanol solution before ultrasonic treatment is 30:136:40. In the system after mixing, the volume ratio of water to isopropanol is 166:147.

[0037] In some preferred embodiments, in S3, the concentration of the AuNR@PEG solution (using a spectrophotometer) before ultrasonic treatment is 15-60 OD, and the concentration of the TEOS-isopropanol solution is 0.97-3.88 v%.

[0038] In some preferred embodiments, the preparation process of the AuNR seed solution specifically includes: adding an ice-bathed NaBH4 solution to a mixed solution of a CTAB solution and a HAuCl4 solution to form a mixed solution, and vigorously stirring the mixed solution until the mixed solution turns brown, thus obtaining the AuNR seed solution.

[0039] In some preferred embodiments, in step S1, the growth solution is specifically formed by mixing a HAuCl4 solution, a CTAB solution, a silver nitrate solution, and an ascorbic acid solution.

[0040] The present invention also claims the application of the silica-coated gold nanorods prepared by the above-mentioned preparation method, especially in the field of pathogen detection.

[0041] The method of the present invention will be further described below in conjunction with the drawings and embodiments. In the following embodiments, conventional instrument equipment in the art is used, and various raw materials and reagents used (such as: organic solvents, inorganic solvents, kinases, substrates, antibodies, buffers, reaction solutions, etc.) are all commercially available products in the conventional sense, with their specifications being the conventional specifications in the art, or can be prepared or formulated by known methods or reagent instructions. For the experimental methods without specific conditions noted in the following embodiments, they are usually carried out under conventional conditions, or according to the conditions recommended by the manufacturer.

[0042] Example 1 1. Preparation of gold nanorods by seed solution method 1) Preparation of AuNR seed solution: Add 0.6 mL of ice-bathed 10 mmol / L NaBH4 solution to a mixed solution of 0.25 mL of 10 mmol / L HAuCl4 and 9.75 mL of 0.1 mol / L CTAB, and stir vigorously at room temperature for 10 minutes. The color of the solution will change from yellow to brown, indicating the formation of gold seeds.

[0043] 2) Preparation of growth solution: Prepare the growth solution by sequentially adding 1 mL of 10 mmol / L aqueous HAuCl4 solution, 20 mL of 0.1 mol / L aqueous CTAB solution, 0.2 mL of 10 mmol / L aqueous AgNO3 solution, and 0.16 mL of 0.1 mol / L ascorbic acid aqueous solution, and then gently invert to mix the solution evenly.

[0044] Mix the AuNR seed solution and the growth solution: Add 48 µL of the seed solution to the growth solution and incubate in the dark for 8 hours. After centrifuging at 11400 rpm for 30 minutes, discard the supernatant, and disperse the precipitate in ultrapure water to form a 5 OD nanorod solution.

[0045] 2. Preparation of AuNR@PEG by PEG-mediated rapid freezing method Take 6 tubes of 400 μL of the gold nanorod solution prepared in step 1 of this example, and add 20 μL of 100 mM SH-PEG 5k -NH2 solution to each tube; Freeze the mixed solution at -80 °C for 15 minutes, take it out and thaw and redissolve it; Centrifuge the redissolved mixed solution at 12400 rpm at 25 °C for 10 minutes to remove the excess supernatant; Wash each tube with 200 μL of PBS buffer (0.01 M, pH = 7.4), centrifuge at 8000 rpm at 25 °C for 10 minutes to remove the excess supernatant, resuspend the remaining liquid in 200 μL of PBS buffer and centrifuge again at 8000 rpm at 25 °C for 10 minutes. After removing the supernatant, resuspend the remaining liquid in 400 μL of ultrapure water. The prepared AuNR@PEG has a concentration of 18 - 20 OD, and store the product at 4 °C.

[0046] 3. Preparation of PEG-AuNR@SiO2 by ultrasonic method with controllable coating of SiO2 Take the AuNR@PEG solution prepared in the previous step and dilute it to 15 OD. Take 0.3 mL of the diluted AuNR@PEG solution and add it to 1.36 mL of water, and sonicate for 15 min. Then, quickly add 1.43 mL of 3.84 v% ammonia-isopropanol solution under the sonication power of 360 W, and then slowly add 0.1 mL each time at intervals of 5 min for a total of 0.4 mL of 0.97 v% TEOS-isopropanol solution in 4 times.

[0047] After completely adding the solution, react it for 2 h in the ultrasonic environment and take it out, take TEM pictures to confirm the completion of the reaction, and the PEG-AuNR@SiO2 solution is obtained at the end of the reaction.

[0048] Then, wash and purify the PEG-AuNR@SiO2 solution for stable storage: divide the PEG-AuNR@SiO2 solution into 400 μL per tube and centrifuge at 12400 rpm for 10 min at 25 °C. After that, perform water washing and centrifugation respectively. The parameters of water washing and centrifugation are 10 min at 8000 rpm at 25 °C, and repeat the operation of water washing and centrifugation with the same parameters. Finally, resuspend the lower layer liquid in 200 μL of ultrapure water, and the PEG-AuNR@SiO2 solution that can be stably stored is obtained after purification.

[0049] Example 2 1. Preparation of gold nanorods by seed solution method Same as step 1 of Example 1.

[0050] 2. Preparation of AuNR@PEG by PEG-mediated rapid freezing method Same as step 2 of Example 1.

[0051] 3. Large-scale preparation of PEG-AuNR@SiO2 Add 0.3 mL of AuNR@PEG solution with a concentration of 60 OD to 1.36 mL of aqueous solution and sonicate and mix for 15 min.

[0052] Then, under the ultrasonic condition of 360 W, quickly add 1.43 mL of ammonia-isopropanol solution with a concentration of 3.84 v% to adjust the pH of the solution system to the optimal pH value of 10.8; then continue under 360 W ultrasound, and add 0.1 mL each time at intervals of 5 min for a total of 0.4 mL of TEOS-isopropanol solution with a concentration of 3.88 v% in 4 times.

[0053] After all the liquids were completely added to the solution, the reaction was carried out for two hours. After the reaction was completed, the PEG-AuNR@SiO2 was centrifuged at 12400 rpm for 10 min at 25 °C in 0.4 mL aliquots per tube, and then washed with water by centrifugation (8000 rpm for 10 min at 25 °C), and the water washing and centrifugation operation was repeated (8000 rpm for 8 min at 25 °C). Finally, it was resuspended in ultrapure water, and a PEG-AuNR@SiO2 solution that could be stably stored was obtained by purification.

[0054] Meanwhile, the following embodiments were also carried out in the present invention: Three sets of parallel experiments were carried out to change the freezing duration at -20 °C, which were 5 min, 15 min, and 30 min respectively; three sets of parallel experiments were carried out to change the freezing duration at -80 °C, which were 5 min, 15 min, and 30 min respectively; three sets of parallel experiments were carried out to change the groups of SH-PEG-X under the freezing condition of -80 °C and 15 min, which were COOH, NH2, and Saline respectively. To avoid repetition, the parameters not listed were the same as those in Example 1.

[0055] Test Example The products prepared in the above embodiments were tested, which will be specifically described below with reference to the accompanying drawings.

[0056] Figure 1 (a) The TEM images of the prepared AuNRs and AuNR@SiO2 synthesized with SH-PEGs having different functional groups show that the presence of Au-S bonds does facilitate the coating of the silicon layer. (b) The UV images of the prepared AuNRs and AuNR@SiO2 synthesized with SH-PEGs having different functional groups show that the coating is relatively uniform. (c) The statistical chart of the silicon layer thickness of the prepared AuNRs and AuNR@SiO2 synthesized with SH-PEGs having different functional groups shows that different functional groups can obtain different silicon layer thicknesses under the same conditions. (d) The zeta potential images of the prepared AuNRs and AuNR@SiO2 synthesized with SH-PEGs having different functional groups show that the reaction using SH-PEG-NH2 is more stable.

[0057] Figure 2For the PEG-mediated rapid freezing method in the embodiments of the present invention, PEG-AuNR@SiO2 was prepared under different conditions. (a) shows the physical pictures of freezing at -20°C for different times. The picture on the top is for 5 minutes of freezing. (b) shows the zeta potential diagrams of freezing at -20°C for different times, indicating that although the freezing time was 30 minutes, the potential was unstable. (c) shows the ultraviolet diagrams of freezing at -20°C for different times, indicating that SH-PEG coated AuNR. (d) shows the physical pictures of freezing at -80°C for different times. It can be seen that all were frozen and there was little difference that could be observed with the naked eye. (e) shows the zeta potential diagrams of freezing at -80°C for different times. The 15-minute freezing duration had the most stable Au-S binding. (f) shows the ultraviolet diagrams of freezing at -80°C for different times, indicating that SH-PEG coated AuNR.

[0058] Figure 3 For the Au-S bonding test results of the PEG-mediated rapid freezing method in the embodiments of the present invention within 15 minutes, Figure 3 is the infrared spectrum after AuNR was incubated with SH-PEG-NH2. The different peak positions are for NH2, which indirectly proves that the 15-minute freezing process at -80°C can complete the Au-S bond formation.

[0059] Figure 4 For the yield results of the embodiments of the present invention and the comparative examples, (a) shows the reagent bottle after the reaction using the stirring method. It can be seen that there is obvious loss in the stirring method. (b) shows the TEM image of AuNR@SiO2 obtained using the stirring method, confirming that there is no significant difference between the ultrasonic method and the traditional stirring method. (c) shows the physical picture of AuNR@SiO2 obtained using the stirring method, further proving that the synthesis yield of the ultrasonic method is higher. (d) shows the reagent bottle after the reaction using the ultrasonic method. It can be seen that the ultrasonic method has less loss than the stirring method. (e) shows the TEM image of AuNR@SiO2 obtained using the ultrasonic method, confirming that there is no significant difference between the ultrasonic method and the traditional stirring method. (f) shows the physical picture of AuNR@SiO2 obtained using the ultrasonic method, further proving that the synthesis yield of the ultrasonic method is higher.

[0060] Figure 5 For the silicon layer thickness under different TEOS volume conditions in the embodiments of the present invention, (a) shows the TEM images under different TEOS volume conditions, from which the change in the silicon layer thickness can be directly seen when different volumes of TEOS are added. (b) shows the ultraviolet diagrams under different TEOS volume conditions, indirectly proving that there is no significant change in the aspect ratio after the silicon layer is coated. (c) shows the data diagrams of the silicon layer thickness under different TEOS volume conditions, using data statistics to show the change in the silicon layer thickness when different volumes of TEOS are added.

[0061] Figure 6The silicon layer thickness under different reaction time conditions in the embodiments of the present invention. (a) The TEM images under different reaction time conditions intuitively show that the silicon layer thickness changes with different reaction times. (b) The ultraviolet images under different reaction time conditions indirectly prove that there is no significant change in the aspect ratio after coating the silicon layer. (c) The data graph of the silicon layer thickness under different reaction time conditions statistically shows the change in the silicon layer thickness at different reaction times.

[0062] Figure 7 The TEM characterization of PEG-AuNR@SiO2 prepared by expanding the reaction system under cryo-ultrasound conditions in the embodiments of the present invention. Different elements are used to characterize that the reaction process is real, reliable, and feasible for coating SH-PEG and SiO2.

[0063] The above content is only to illustrate the technical idea of the present invention, and the protection scope of the present invention cannot be limited thereby. Any modification made on the basis of the technical solution according to the technical idea proposed by the present invention falls within the protection scope of the claims of the present invention.

Claims

1. A method for preparing gold nanorod-coated silicon materials with rapid controllability, characterized in that, It includes the following steps: S1. Prepare an AuNR seed solution and a growth solution using CTAB, mix the AuNR seed solution and the growth solution, and dissolve the precipitate to obtain a gold nanorod solution; S2. Add SH-PEG 5k -X solution to the gold nanorod solution, freeze, thaw and redissolve, then centrifuge, wash and dissolve to obtain the AuNR@PEG solution; S3. Add the AuNR@PEG solution to water for ultrasonic dispersion, sequentially add an ammonia - isopropanol solution and a TEOS - isopropanol solution, and react to obtain PEG - AuNR@SiO2, that is, the silicon - coated gold nanorod material.

2. The method for preparing the silica-coated gold nanorods with fast controllability according to claim 1, wherein, In the step S2, the freezing temperature is - 80 to - 20 °C, and the freezing time is 5 to 30 min.

3. The method for preparing a silica-coated gold nanorod material with rapid controllability according to claim 1, wherein In the step S2, the volume ratio of the gold nanorod solution to the SH-PEG 5k -X solution is 20:1, where the concentration of the gold nanorod solution is 5 OD, and the concentration of SH-PEG 5k -X is 100 mM.

4. The method for preparing a silicon-coated gold nanorod material with fast controllability according to claim 1, characterized in that, In S3, the AuNR@PEG solution is mixed with water and ultrasonicated. After the AuNR@PEG solution is monodispersed, the ammonia - isopropanol solution is first added under ultrasonic conditions with a power of 300 - 400 W, and then the TEOS - isopropanol solution is added in portions.

5. The method for preparing the silica-coated gold nanorods with fast controllability according to claim 4, characterized in that, In S3, the pH value of the mixed solution is adjusted to 10 - 11 by adding the ammonia - isopropanol solution.

6. The method for preparing a silica-coated gold nanorod material with fast controllability according to claim 4, characterized in that, The volume ratio of the AuNR@PEG solution, water, and the TEOS - isopropanol solution is 30:136:

40.

7. The method for preparing the silicon-coated gold nanorod material with fast controllability according to claim 4, wherein Before the ultrasonic treatment, the concentration of the AuNR@PEG solution is 15 - 60 OD, and the concentration of the TEOS - isopropanol solution is 0.97 - 3.88 v%.

8. The method for preparing the silicon-coated gold nanorod material with fast controllability according to claim 1, wherein In the step S1, the preparation process of the AuNR seed solution specifically includes: adding an ice - bathed NaBH4 solution to a mixed solution of a CTAB solution and an HAuCl4 solution to form a mixed solution, and vigorously stirring the mixed solution until the mixed solution turns brown, thus obtaining the AuNR seed solution.

9. The method for preparing the silica-coated gold nanorods with fast controllability according to claim 1, wherein, In the step S1, the growth solution is specifically formed by mixing an HAuCl4 solution, a CTAB solution, a silver nitrate solution, and an ascorbic acid solution.

10. Application of the silicon - coated gold nanorod material prepared by the method for preparing a rapidly controllable silicon - coated gold nanorod material according to claims 1 to 9 in the field of pathogen detection.

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