Preparation method of mesoporous silica-platinum Janus nanomotor

Abstract

The present invention belongs to the technical field of functional nanomaterials, and specifically relates to a method for preparing a mesoporous silica-platinum Janus nanomotor. The preparation method uses tetraethyl orthosilicate and bis-[γ-(triethoxysilyl)propyl]-tetrasulfide as silicon sources and hexadecyltrimethylammonium bromide as a pore-forming agent to synthesize mesoporous silica nanospheres. 3-aminopropyltrimethoxysilane is used to modify the amino groups, polyethyleneimine is coupled to the mesoporous silica nanospheres by glutaraldehyde, and then chloroplatinic acid is adsorbed onto the mesoporous silica nanospheres by electrostatic adsorption. Hydrazine hydrate is used as a reducing agent to reduce the chloroplatinic acid, and finally a mesoporous silica-platinum Janus nanomotor is formed; the nanomotor is anisotropic particles composed of mesoporous silica spheres and metallic platinum. The preparation method of the mesoporous silica-platinum Janus nanomotor provided by the present invention has the advantages of simple operation, no need for special equipment, and batch preparation.

Description

Technical Field

[0001] The present invention belongs to the technical field of functional nanomaterials, and in particular relates to a method for preparing a mesoporous silica-platinum Janus nanomotor. Background Art

[0002] Janus nanoparticles, as nanomaterials with asymmetric structures, can integrate two or more chemical components within a single particle, exhibiting distinct physical and chemical properties. Currently, the main methods for preparing Janus nanoparticles include physical vapor deposition (PVD), electrochemical deposition, microfluidics, and self-assembly methods (such as Pickering emulsions, transient nanoprecipitation, and selective growth). However, these methods are costly, complex, or require specialized equipment, making controlled synthesis and mass production difficult.

[0003] Nanomotors are artificial actuators at the nanoscale that can convert various energies (chemical, magnetic, ultrasonic, and light) into mechanical energy for autonomous motion. They show great potential for applications in drug delivery, environmental remediation, cargo transport, sensing, and microfabrication. MSiO2-Pt Janus nanoparticles, composed of nonmetallic MSiO2 and metallic Pt, are an excellent candidate for nanomotors due to their large surface area, enabling them to load a large number of small molecule targets. Pt catalyzes H2O2 to produce O2, thereby propelling the particles through a jet-like action. In addition to the traditional preparation methods mentioned above, Díez et al. (ACS Nano 2021, 15, 4467–4480) developed a method for fabricating MSiO2-Pt Janus nanomotors by masking one side of an MSiO2 sphere with paraffin wax and then directing the growth of Pt. However, complete encapsulation of MSiO2 within the paraffin wax surface presents significant challenges, making blank MSiO2 spheres unavoidable within the MSiO2-Pt Janus nanomotors.

[0004] Therefore, it is of great significance to develop a synthetic method for MSiO2-Pt Janus nanomotors with low cost, simple preparation process, easy mass production and high product quality. Summary of the Invention

[0005] The purpose of the present invention is to overcome the current problems of high preparation cost, lack of operational convenience, and difficulty in mass production of Janus motors, and to provide a method for preparing mesoporous silica-platinum Janus nanomotors.

[0006] In order to achieve the above technical objectives and the above technical effects, the present invention is implemented through the following technical solutions:

[0007] A method for preparing mesoporous silica-platinum Janus nanomotors comprises the following steps: using tetraethyl orthosilicate and bis-[γ-(triethoxysilyl)propyl]-tetrasulfide as silicon sources and cetyltrimethylammonium bromide as a pore-forming agent to synthesize mesoporous silica nanospheres; using 3-aminopropyltrimethoxysilane to modify the mesoporous silica nanospheres with amino groups; coupling polyethyleneimine with the mesoporous silica nanospheres via glutaraldehyde; then adsorbing chloroplatinic acid onto the mesoporous silica nanospheres via electrostatic adsorption; and reducing the mesoporous silica nanospheres with hydrazine hydrate as a reducing agent to ultimately form the mesoporous silica-platinum Janus nanomotors.

[0008] Furthermore, the method for preparing the mesoporous silica-platinum Janus nanomotor as described above specifically comprises the following steps:

[0009] 1) Preparation of MSiO2: Cetyltrimethylammonium bromide is dissolved in a mixture of water and anhydrous ethanol, stirred at 35°C for a period of time, and then ethyl orthosilicate and bis-[γ-(triethoxysilyl)propyl]-tetrasulfide are rapidly added, and the reaction is continued with rapid stirring for 12 to 48 hours; the product is collected by centrifugation at a certain speed and washed 2 to 3 times with anhydrous ethanol. The collected product is dispersed in anhydrous ethanol, concentrated HCl is added, and stirred at 60°C for a period of time. The process is repeated three times to fully remove the template cetyltrimethylammonium bromide. The final product is collected by centrifugation and washed with ethanol to obtain MSiO2 with the template removed;

[0010] 2) Surface modification of MSiO2: The template-removed MSiO2 was dispersed in anhydrous ethanol, and 3-aminopropyltrimethoxysilane was slowly added dropwise under stirring. The mixture was stirred overnight. After the reaction, the mixture was centrifuged and washed with anhydrous ethanol. The product was dispersed in water, glutaraldehyde was added at 37°C, and the mixture was reacted for 12 to 48 hours under continuous stirring. After the reaction, the mixture was centrifuged again and washed with deionized water 2 to 3 times. The product was dispersed in water, an appropriate amount of polyethyleneimine was dissolved in water, and the product was added under stirring. The mixture was reacted at 37°C for 12 to 48 hours. After the reaction, the product was collected by centrifugation and washed with deionized water 2 to 3 times to obtain PEI-modified MSiO2.

[0011] 3) Synthesis of MSiO2-Pt: The PEI-modified MSiO2 was redispersed in deionized water, and chloroplatinic acid solution was added. The mixture was allowed to stand for adsorption for 10-14 hours. Finally, it was centrifuged, washed with water, and redispersed in deionized water. Hydrazine hydrate solution was added to the product and rapidly shaken until the color changed from yellow to black. The reaction was continued on a shaker for a period of time to obtain MSiO2-Pt.

[0012] Furthermore, in step 1), the volume ratio of ethyl orthosilicate to bis-[γ-(triethoxysilyl)propyl]-tetrasulfide is 1 to 4:1.

[0013] Furthermore, in step 2), the mass fraction of glutaraldehyde is 50%.

[0014] Furthermore, in step 2), the MW of polyethyleneimine is 10 kDa.

[0015] Furthermore, in step 3), the mass fraction of the chloroplatinic acid solution is 1%.

[0016] Furthermore, in step 3), the mass fraction of the hydrazine hydrate solution is 40 to 85%.

[0017] A mesoporous silica-platinum Janus nanomotor is prepared according to the above preparation method.

[0018] The beneficial effects of the present invention are:

[0019] The preparation method of the mesoporous silica-platinum Janus nanomotor provided by the present invention has the advantages of simple operation, no need for special equipment, and batch preparation.

[0020] Of course, any product implementing the present invention does not necessarily need to achieve all of the above advantages at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0022] Figure 1 TEM image of MSiO2-Pt prepared in Example 1 of the present invention;

[0023] Figure 2 This is a flow chart for the preparation of MSiO2 in the present invention. DETAILED DESCRIPTION

[0024] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0025] Example 1

[0026] 1) Preparation of MSiO2: This method uses a surfactant-guided sol-gel method to prepare MSiO2, such as Figure 2As shown. 0.4g of CTAB was dissolved in a mixture of 650mL of water and 150mL of anhydrous ethanol, stirred at 35°C for 2h, then 0.8mL of TEOS and 0.2mL of BTES were quickly added and the reaction was continued with rapid stirring for 24h. The product was collected by centrifugation at 10,000rpm and washed twice with ethanol. The collected product was dispersed in 100mL of ethanol, 200μL of concentrated HCl was added, and stirred at 60°C for 3h. This treatment was repeated three times to remove the template CTAB. The final product was collected after centrifugation and alcohol washing.

[0027] 2) Surface Modification of MSiO2: The de-templated MSiO2 was dispersed in 10 mL of anhydrous ethanol. 100 μL of APTMS was slowly added dropwise with stirring and stirred overnight. After the reaction, the mixture was centrifuged and washed twice with anhydrous ethanol. The product was then dispersed in 10 mL of water. 500 μL of 50% GA was added and the mixture was stirred for 24 hours at 37°C. After the reaction, the mixture was centrifuged again and washed twice with deionized water. The product was then dispersed in 10 mL of water. An appropriate amount of PEI (MW = 10 kDa) was dissolved in 5 mL of water and added to the 10 mL of product with stirring. The mixture was stirred at 37°C for 24 hours. After the reaction, the product was centrifuged and washed twice with water before being collected.

[0028] 3) Synthesis of MSiO2-Pt: Re-disperse the PEI-modified MSiO2 in 5 mL of deionized water and add 1 mL of H2PtCl6 (1%). Allow to stand for 12 hours of adsorption, then centrifuge and wash once before redispersing in 5 mL of water. Take 500 μL of the product and add 200 μL of N2H4·H2O (85%). Shake well at room temperature until the color changes from yellow to black. Continue the reaction on a shaker for 2 hours to obtain MSiO2-Pt, as shown in TEM images. Figure 1 shown.

[0029] Example 2

[0030] 1) Preparation of MSiO2: This method uses a surfactant-guided sol-gel method to prepare MSiO2. 0.4g CTAB was dissolved in a mixture of 650mL water and 150mL anhydrous ethanol, stirred at 35°C for 2h, and then 0.8mL TEOS and 0.2mL BTES were quickly added and the reaction was continued with rapid stirring for 24h. The product was collected by centrifugation at 10,000rpm and washed three times with ethanol. The collected product was dispersed in 100mL ethanol, 200μL concentrated HCl was added, and stirred at 60°C for 3h. This treatment was repeated three times to remove the template CTAB. The final product was collected after centrifugation and alcohol washing.

[0031] 2) Surface Modification of MSiO2: The de-templated MSiO2 was dispersed in 10 mL of anhydrous ethanol. 100 μL of APTMS was slowly added dropwise with stirring and stirred overnight. After the reaction, the mixture was centrifuged and washed twice with anhydrous ethanol. The product was then dispersed in 10 mL of water. 500 μL of 50% GA was added and the mixture was stirred for 24 hours at 37°C. After the reaction, the mixture was centrifuged again and washed three times with deionized water. The product was then dispersed in 10 mL of water. An appropriate amount of PEI (MW = 10 kDa) was dissolved in 5 mL of water and added to the 10 mL of the product with stirring. The mixture was stirred at 37°C for 24 hours. After the reaction, the product was centrifuged and washed twice with water before being collected.

[0032] 3) Synthesis of MSiO2-Pt: Redisperse the PEI-modified MSiO2 in 5 mL of deionized water and add 1 mL of 1% H2PtCl6. Allow to adsorb for 12 h. Finally, centrifuge, rinse once, and redisperse in 5 mL of water. Add 500 μL of the product to 200 μL of 45% N2H4·H2O. Shake rapidly until the color changes from yellow to black. Continue the reaction on a shaker for 2 h to obtain MSiO2-Pt.

[0033] Example 3

[0034] 1) Preparation of MSiO2: This method uses a surfactant-guided sol-gel method to prepare MSiO2. 0.4g CTAB was dissolved in a mixture of 650mL water and 150mL anhydrous ethanol, stirred at 35°C for 2h, and then 0.8mL TEOS and 0.2mL BTES were quickly added. The reaction was stirred rapidly for 24h. The product was collected by centrifugation at 10,000rpm and washed twice with ethanol. The collected product was dispersed in 100mL ethanol, 200μL concentrated HCl was added, and stirred at 60°C for 3h. This treatment was repeated three times to remove the template CTAB. The final product was collected after centrifugation and alcohol washing.

[0035] 2) Surface Modification of MSiO2: The de-templated MSiO2 was dispersed in 10 mL of anhydrous ethanol. 100 μL of APTMS was slowly added dropwise with stirring and stirred overnight. After the reaction, the mixture was centrifuged and washed twice with anhydrous ethanol. The product was then dispersed in 10 mL of water. 500 μL of 50% GA was added and the mixture was stirred for 24 hours at 37°C. After the reaction, the mixture was centrifuged again and washed twice with deionized water. The product was then dispersed in 10 mL of water. An appropriate amount of PEI (MW = 10 kDa) was dissolved in 5 mL of water and added to the 10 mL of product with stirring. The mixture was stirred at 37°C for 24 hours. After the reaction, the product was centrifuged and washed twice with water before being collected.

[0036] 3) Synthesis of MSiO2-Pt: The PEI-modified MSiO2 was redispersed in 5 mL of deionized water and 1 mL of 1% H2PtCl6 was added. The mixture was allowed to adsorb for 12 h. Finally, it was centrifuged, washed once, and redispersed in 5 mL of water. 500 μL of the product was added to 200 μL of 45% N2H4·H2O. The mixture was rapidly shaken in an ice bath until the color changed from yellow to black. The reaction was continued on a shaker for 2 h to obtain MSiO2-Pt.

[0037] Example 4

[0038] 1) Preparation of MSiO2: This method uses a surfactant-guided sol-gel method to prepare MSiO2. 0.4g CTAB was dissolved in a mixture of 650mL water and 150mL anhydrous ethanol, stirred at 35°C for 2h, and then 0.8mL TEOS and 0.2mL BTES were quickly added and the reaction was continued with rapid stirring for 24h. The product was collected by centrifugation at 10,000rpm and washed three times with ethanol. The collected product was dispersed in 100mL ethanol, 200μL concentrated HCl was added, and stirred at 60°C for 3h. This treatment was repeated three times to remove the template CTAB. The final product was collected after centrifugation and alcohol washing.

[0039] 2) Surface Modification of MSiO2: The de-templated MSiO2 was dispersed in 10 mL of anhydrous ethanol. 100 μL of APTMS was slowly added dropwise with stirring and stirred overnight. After the reaction, the mixture was centrifuged and washed twice with anhydrous ethanol. The product was then dispersed in 10 mL of water. 500 μL of 50% GA was added and the mixture was stirred for 24 hours at 37°C. After the reaction, the mixture was centrifuged again and washed three times with deionized water. The product was then dispersed in 10 mL of water. An appropriate amount of PEI (MW = 10 kDa) was dissolved in 5 mL of water and added to the 10 mL of the product with stirring. The mixture was stirred at 37°C for 24 hours. After the reaction, the product was centrifuged and washed twice with water before being collected.

[0040] 3) Synthesis of MSiO2-Pt: Redisperse the PEI-modified MSiO2 in 5 mL of deionized water and add 1 mL of 1% H2PtCl6. Allow to adsorb for 12 h. Finally, centrifuge, rinse once, and redisperse in 5 mL of water. Add 500 μL of the product to 200 μL of 85% N2H4·H2O. Shake rapidly in an ice bath until the color changes from yellow to black. Continue the reaction on a shaker for 2 h.

[0041] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to specific embodiments. Obviously, many modifications and variations are possible based on the contents of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for preparing a mesoporous silica-platinum Janus nanomotor, characterized in that: The preparation method uses tetraethyl orthosilicate and bis-[γ-(triethoxysilyl)propyl]-tetrasulfide as silicon sources and hexadecyltrimethylammonium bromide as a pore-forming agent to synthesize mesoporous silica nanospheres; 3-aminopropyltrimethoxysilane is used to modify the mesoporous silica nanospheres with amino groups; polyethyleneimine is coupled to the mesoporous silica nanospheres via glutaraldehyde; chloroplatinic acid is then adsorbed onto the mesoporous silica nanospheres via electrostatic adsorption; and hydrazine hydrate is used as a reducing agent to reduce the chloroplatinic acid, ultimately forming mesoporous silica-platinum Janus nanomotors. It specifically includes the following steps: 1) Preparation of MSiO2: Cetyltrimethylammonium bromide is dissolved in a mixture of water and anhydrous ethanol, stirred at 35°C for a period of time, and then ethyl orthosilicate and bis-[γ-(triethoxysilyl)propyl]-tetrasulfide are rapidly added, and the reaction is continued with rapid stirring for 12 to 48 hours; the product is collected by centrifugation at a certain speed and washed 2 to 3 times with anhydrous ethanol. The collected product is dispersed in anhydrous ethanol, concentrated HCl is added, and stirred at 60°C for a period of time. The process is repeated three times to fully remove the template cetyltrimethylammonium bromide. The final product is collected by centrifugation and washed with ethanol to obtain MSiO2 with the template removed; 2) Surface modification of MSiO2: The template-removed MSiO2 was dispersed in anhydrous ethanol, and 3-aminopropyltrimethoxysilane was slowly added dropwise under stirring. The mixture was stirred overnight. After the reaction, the mixture was centrifuged and washed with anhydrous ethanol. The product was dispersed in water, glutaraldehyde was added at 37°C, and the mixture was reacted for 12 to 48 hours under continuous stirring. After the reaction, the mixture was centrifuged again and washed with deionized water 2 to 3 times. The product was dispersed in water, an appropriate amount of polyethyleneimine was dissolved in water, and the product was added under stirring. The mixture was reacted at 37°C for 12 to 48 hours. After the reaction, the product was collected by centrifugation and washed with deionized water 2 to 3 times to obtain PEI-modified MSiO2. 3) Synthesis of MSiO2-Pt: The PEI-modified MSiO2 was redispersed in deionized water, and chloroplatinic acid solution was added. The mixture was allowed to stand for adsorption for 10-14 hours. Finally, it was centrifuged, washed with water, and redispersed in deionized water. Hydrazine hydrate solution was added to the product and rapidly shaken until the color changed from yellow to black. The reaction was continued on a shaker for a period of time to obtain MSiO2-Pt.

2. The method for preparing a mesoporous silica-platinum Janus nanomotor according to claim 1, characterized in that: In step 1), the volume ratio of ethyl orthosilicate to bis-[γ-(triethoxysilyl)propyl]-tetrasulfide is 1 to 4:

1.

3. The method for preparing a mesoporous silica-platinum Janus nanomotor according to claim 1, wherein: In step 2), the mass fraction of glutaraldehyde is 50%.

4. The method for preparing a mesoporous silica-platinum Janus nanomotor according to claim 1, wherein: In step 2), the MW of polyethyleneimine is 10 kDa.

5. The method for preparing a mesoporous silica-platinum Janus nanomotor according to claim 1, wherein: In step 3), the mass fraction of the chloroplatinic acid solution is 1%.

6. The method for preparing a mesoporous silica-platinum Janus nanomotor according to claim 1, characterized in that: In step 3), the mass fraction of the hydrazine hydrate solution is 40 to 85%.

7. A mesoporous silica-platinum Janus nanomotor prepared according to the preparation method according to any one of claims 1 to 6.

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