Method for preparing double-layer silicon dioxide nanotube

Abstract

The invention discloses a preparation method of a double-layer silicon dioxide nanotube, belongs to the technical field of new materials, and solves the manufacturing problem of a relatively fine and uniform silicon dioxide tubular structure. According to the method, amphiphilic oligopeptide synthesized by rational design is used as a raw material, self-assembly of the oligopeptide is regulated and controlled in an aqueous solution, an oligopeptide self-assembly nanotube template is formed, and the tube diameter of a tubular assembly is more uniform through repeated heat treatment. The self-assembly solution is diluted, and an HEPES buffer solution is introduced, so that the pH value of the solution is about 7; adding 1% by volume of tetraethoxysilane (TEOS) as a silicon source for template assembly, and removing the nanotube template through a high-temperature firing method after assembly is completed and completely converting the silicon source into silicon dioxide. The silicon dioxide nanotube prepared by the invention has a fine double-layer sleeve structure, can provide a larger specific surface area, can bear more active sites as a catalyst component, can better encapsulate and release drugs by utilizing interlamellar gaps when being used in a drug delivery system, and has a wide application prospect.

Description

Technical Field

[0001] The invention belongs to the technical field of new material manufacturing, and specifically relates to a method for preparing double-layer silicon dioxide nanotubes. Background Art

[0002] Silica nanotubes have the advantages of high surface area and excellent mechanical properties, and are widely used in many fields, including electronic devices, catalysts, sensors and drug delivery. At present, the main methods for preparing silica nanotubes are solution-gel method, chemical vapor deposition method, template method and self-assembly method. Among them, the solution-gel method uses silica precursors and is simple to operate; the template method can accurately control the size and shape of the tube and is suitable for specific application scenarios. The templates commonly used in the template method are anodized aluminum films (hard templates), polymers (soft templates) and certain porous materials. The final silica nanostructure is closely related to the morphology of the template.

[0003] In the current preparation methods, the silica nanotubes obtained are often single-layer structures obtained by means such as template methods based on fibrous templates, and the diameter distribution range is relatively large. For example, a known method for preparing carbon nanotubes using carbon nanostructures as templates and dimethyl silicone oil as a silicon source has a diameter distribution range of 10-110nm, which is 10 times different. There is still a lack of methods for preparing nanotubes with fine structures such as double-layer wall structures, and the existing preparation methods are mostly for obtaining double-layer vesicles and layered structures. In this context, the preparation of silica nanotubes with a double-layer structure and a relatively uniform diameter is significantly innovative. Silica nanotubes with a double-layer structure can provide a larger specific surface area, can carry more active sites as a catalyst component, and can use the interlayer gap to better encapsulate and control the release of drugs when used in drug delivery systems, and have broad application prospects.

[0004] This method is based on the tubular structure in the nanostructure formed by the self-assembly of amphiphilic short peptides. Different from the general fiber or rod-shaped template, the tubular template enables the silicon source to simultaneously construct silica nanotubes on the inside and outside of the tubular structure template, and finally obtain double-layer silica nanotubes. The diameter of the obtained nanotubes is relatively uniform, and the reaction conditions are mild and easy to implement. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention proposes a new method for preparing double-layer silica nanotubes with a specific diameter by using amphiphilic short peptide self-assembled nanotubes as a template. The diameter of the obtained double-layer silica nanotubes is relatively uniform, and the reaction conditions are mild and easy to implement.

[0006] The present invention is implemented by the following technical solutions:

[0007] By using short peptide self-assembly technology and using amphiphilic short peptide self-assembled nanotubes as templates for silica deposition, double-layer silica nanotubes with uniform diameters can be obtained. The organic short peptide nanotubes used as templates can be easily removed by burning.

[0008] The specific steps include:

[0009] Step 1: Add the designed and synthesized amphiphilic short peptide into water to make it dissolve evenly to prepare a self-assembly solution;

[0010] Step 2: Seal the prepared peptide solution, place it in a water bath for heating, and repeat the heating process three times to adjust the template morphology to obtain a peptide nanotube template with a tube diameter of about 35-40 nanometers;

[0011] Step 3: Introduce a buffer into the solution, add water to adjust the concentration of the buffer and the short peptide, and keep the pH of the system neutral;

[0012] Step 4: adding 1% by volume of tetraethoxysilane as a reaction substrate, using short peptide self-assembled nanotubes as a template to enrich the silicon source on the surface of the assembly;

[0013] Step 5: freeze-dry the solution after the reaction, and place the freeze-dried and dehydrated powder into a muffle furnace for calcination to completely convert the silicon source into silicon dioxide and remove the short peptide nanotube template, thereby obtaining a relatively uniform double-layer silicon dioxide nanotube structure.

[0014] Furthermore, the monomer of the peptide assembly as the silica nanotube template is an amphiphilic short peptide L D LL D LK (L: leucine residue, D L: D-leucine residue; K: lysine residue).

[0015] Furthermore, the method for preparing peptide nanotubes as templates is characterized in that: in the step 1, the amphiphilic short peptide L D LL D The concentration of LK is 16mmol / L; during the repeated heating process, each heating is gradually heated to 80 degrees Celsius, maintained at 80 degrees Celsius for two hours, and then naturally cooled to room temperature.

[0016] Furthermore, the introduced buffer solution is HEPES (4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid) buffer solution, and the composition of the mixed reaction solution is HEPES concentration 25mmol / L, L D LL D LK concentration is 2-8mmol / L.

[0017] Furthermore, the method for removing the short peptide nanotube template and obtaining the double-layer silica nanotube structure is characterized in that: in the step five, the organic peptide nanotube template is removed by calcining at 550 degrees Celsius in a muffle furnace for 8 hours, and the silicon source substrate and intermediate products are completely converted into silica to obtain a uniform double-layer silica nanotube structure.

[0018] The double-layered silica nanotubes prepared by the present invention can provide a larger specific surface area, can carry more active sites as catalyst components, and can utilize interlayer gaps to better encapsulate and control drug release when used in drug delivery systems, thus having broad application prospects.

[0019] Beneficial effects of the present invention:

[0020] 1. Using amphiphilic short peptide nanotubes as templates, different short peptide sequences can be rationally designed and assembly conditions can be optimized to obtain nanotube templates with different diameters and uniform sizes.

[0021] 2. Using amphiphilic short peptide nanotubes as templates and tetraethoxysilane as a silicon source, its assembly on the template is regulated, and the assembled freeze-dried powder can be simply calcined at high temperature to obtain a uniform double-layer silica nanotube structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings are used to provide further explanation of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0023] Figure 1 For L D LL D Cryo-electron microscopy images of nanotubes formed as templates after multiple heat treatments of LK short peptides.

[0024] Figure 2 This is a TEM image of the assembly in Example 1 that has not been subjected to high-temperature treatment in a muffle furnace, which clearly shows the double-layer tube structure generated by the silicon source gathering on both sides of the template nanotube.

[0025] Figure 3 This is a TEM image of the product obtained in Example 1, showing the prepared double-layer silica nanotube structure.

[0026] Figure 4 This is a TEM image of the product obtained in Example 2, showing the effect of reducing the peptide template concentration during the template assembly process. While generating double-layer silica nanotubes, structures such as silica nanoparticles and silica nanobelts appeared.

[0027] Figure 5This is a TEM image of the assembly in the reaction solution of Example 3 before high-temperature calcination treatment, showing the uneven distribution of the silicon source outside the template tube.

[0028] Figure 6 The TEM image of the product obtained in Example 3 shows the result when the peptide template concentration increases during the template assembly process. During the high-temperature calcination treatment, the outer layer of the double-layered silica nanotubes collapsed due to incomplete structure, resulting in failure to produce uniform double-layered silica nanotubes. DETAILED DESCRIPTION

[0029] The present invention is further described below in conjunction with the accompanying drawings and specific examples, but the scope of protection claimed by the present invention is not limited to the scope described in the embodiments.

[0030] A method for preparing double-layer silica nanotubes, characterized in that short peptide self-assembly technology is used to deposit silica using short peptide self-assembled nanotubes as templates, thereby obtaining double-layer silica nanotubes with uniform tube diameters. The organic short peptide used as a template can be easily removed by high-temperature calcination. The specific implementation process includes the following steps: Step 1: Add the designed and synthesized amphiphilic short peptide into water to make it dissolve evenly and prepare a self-assembly solution; Step 2: Seal the prepared peptide solution, put it into a water bath for heating, repeat the heating process three times to adjust the template morphology, and obtain a peptide nanotube template with a tube diameter of about 35-40 nanometers; Step 3: Introduce a buffer solution into the solution, add water to adjust the concentration of the buffer solution and the short peptide, and keep the pH of the system neutral; Step 4: Add 1% by volume of tetraethoxysilane as a reaction substrate, and use the short peptide self-assembled nanotubes as a template to enrich the silicon source on the surface of the assembly; Step 5: Freeze-dry the solution after the reaction, and put the freeze-dried and dehydrated powder into a muffle furnace for calcination to completely convert the silicon source into silicon dioxide and remove the short peptide nanotube template to obtain a relatively uniform double-layer silicon dioxide nanotube structure.

[0031] Example 1

[0032] Step 1: Add the amphiphilic short peptide L D LL D LK was added into water to make it dissolve evenly, and a self-assembly solution with a concentration of 8 mmol / L was prepared;

[0033] Step 2: Seal the prepared peptide solution, place it in a water bath, gradually raise the temperature to 80 degrees Celsius and maintain it for at least two hours, then cool it down. Repeat this process two to three times to obtain a peptide nanotube template with a tube diameter of about 38 nanometers;

[0034] Step 3: Introduce HEPES buffer into the solution and adjust the proportion of each component to make the HEPES concentration 25mmol / L, L D LL DThe LK concentration was 2 mmol / L, and the pH was adjusted to near neutral;

[0035] Step 4: Add 1% by volume of tetraethoxysilane as a reaction substrate, D LL D LK self-assembled nanotubes are used as templates to enrich the silicon source on the surface of the assembly;

[0036] Step 5: After 4 days of reaction, the solution was freeze-dried and the freeze-dried dehydrated structure was placed in a muffle furnace and burned at 550 degrees Celsius for eight hours to completely convert the silicon source into silicon dioxide and remove the short peptide nanotube template. The results are shown in the attached figure. Figure 3 shown.

[0037] Example 2

[0038] Step 1: Add the amphiphilic short peptide L D LL D LK was added into water to make it dissolve evenly, and a self-assembly solution with a concentration of 16 mmol / L was prepared;

[0039] Step 2: Seal the prepared peptide solution, place it in a water bath, gradually raise the temperature to 80 degrees Celsius and maintain it for at least two hours, then cool it down. Repeat this process three times to obtain a peptide nanotube template with a tube diameter of about 38 nanometers;

[0040] Step 3: Introduce HEPES buffer into the solution and adjust the proportion of each component to make the HEPES concentration 25mmol / L, L D LL D The LK concentration was 1 mmol / L, and the pH was adjusted to near neutrality;

[0041] Step 4: Add 1% by volume of tetraethoxysilane as a reaction substrate, D LL D LK self-assembled nanotubes are used as templates to enrich the silicon source on the surface of the assembly;

[0042] Step 5: After 4 days of reaction, the reacted solution is freeze-dried, and the freeze-dried dehydrated structure is placed in a muffle furnace and calcined at 550 degrees Celsius for eight hours to completely convert the silicon source into silicon dioxide and remove the short peptide nanotube template.

[0043] Example 3

[0044] Step 1: Add the amphiphilic short peptide L D LL D LK was added into water to make it dissolve evenly, and a self-assembly solution with a concentration of 16 mmol / L was prepared;

[0045] Step 2: Seal the prepared peptide solution, place it in a water bath, gradually raise the temperature to 80 degrees Celsius and maintain it for at least two hours, then cool it down. Repeat this process two to three times to obtain a peptide nanotube template with a tube diameter of about 38 nanometers;

[0046] Step 3: Introduce HEPES buffer into the solution and adjust the proportion of each component to make the HEPES concentration 25mmol / L, L D LL D The LK concentration was 4 mmol / L, and the pH was adjusted to near neutral;

[0047] Step 4: Add 1% by volume of tetraethoxysilane as a reaction substrate, D LL D LK self-assembled nanotubes are used as templates to enrich the silicon source on the surface of the assembly;

[0048] Step 5: After 4 days of reaction, the reacted solution is freeze-dried, and the freeze-dried dehydrated structure is placed in a muffle furnace and calcined at 550 degrees Celsius for eight hours to completely convert the silicon source into silicon dioxide and remove the short peptide nanotube template.

[0049] The above examples only express several embodiments of the present invention, and the description is relatively specific and detailed, but the technical scope is not limited to the above embodiments. For those skilled in the art, various improvements and implementations can be made without departing from the concept of the present invention. Any modification, equivalent replacement or improvement made within the spirit and principle of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. A method for preparing double-layer silica nanotubes, characterized in that By using the short peptide self-assembly technology and using the amphiphilic short peptide self-assembled nanotubes as templates for silica deposition, double-layer silica nanotubes with uniform tube diameters can be obtained. The organic short peptide nanotubes used as templates can be easily removed by burning. Specifically, the following steps are included: Step 1: Add the designed and synthesized amphiphilic short peptide into water to make it dissolve evenly to prepare a self-assembly solution; Step 2: Seal the prepared peptide solution, place it in a water bath for heating, and repeat the heating process three times to adjust the template morphology to obtain a peptide nanotube template with a tube diameter of about 35-40 nanometers; Step 3: Introduce a buffer into the solution, add water to adjust the concentration of the buffer and the short peptide, and keep the pH of the system neutral; Step 4: adding 1% by volume of tetraethoxysilane as a reaction substrate, using short peptide self-assembled nanotubes as a template to enrich the silicon source on the surface of the assembly; Step 5: freeze-dry the solution after the reaction, and place the freeze-dried and dehydrated powder into a muffle furnace for calcination to completely convert the silicon source into silicon dioxide and remove the short peptide nanotube template, thereby obtaining a relatively uniform double-layer silicon dioxide nanotube structure.

2. According to claim 1, the monomer of the peptide assembly as the silica nanotube template is an amphiphilic short peptide L D LL D LK (L: leucine residue, D L: D-leucine residue; K: lysine residue).

3. A method for preparing peptide nanotubes as templates according to claims 1 and 2, characterized in that: In the step 1, the amphiphilic short peptide L D LL D The concentration of LK is 16mmol / L; during the repeated heating process, each heating is gradually heated to 80 degrees Celsius, maintained at 80 degrees Celsius for two hours, and then naturally cooled to room temperature.

4. According to step 3 of claim 1, the introduced buffer is HEPES (N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid) buffer solution, and the composition of the mixed reaction solution is HEPES concentration 25mmol / L, L D LL D LK concentration is 2-8mmol / L.

5. The method for removing the short peptide nanotube template and obtaining the double-layer silica nanotube structure according to step 5 of claim 1, characterized in that: In the step 5, the organic peptide nanotube template is removed by calcining at 550 degrees Celsius in a muffle furnace for 8 hours, and the silicon source substrate and intermediate products are completely converted into silicon dioxide to obtain a uniform double-layer silicon dioxide nanotube structure.

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