Preparation method of a magnetically driven hammer-shaped swimming nanorobot

Abstract

The present invention discloses a magnetically driven hammer-like swimming nanorobot with a hollow capsule structure and a preparation method thereof, which belongs to the field of swimming nanorobots in biomedical technology. The present invention aims to solve the problems of motion control and cargo loading of existing swimming nanorobots. The present invention provides a unique asymmetric structure and has a better load capacity than other swimming nanorobots. Method: 1. Prepare magnetic peanut-shaped α-Fe2O3 micro-nanoparticles; 2. Prepare magnetic hammer-like nanoparticles; 3. Prepare a hammer-like swimming nanorobot with a hollow capsule structure. The present invention is simple and easy to implement, with stable process, good repeatability, and is convenient for mass production. The prepared hammer-like swimming nanorobot with a microcapsule structure has good transportability and load-bearing function. The artificial hammer-like swimming nanorobot prepared by the present invention is used in the medical field.

Description

Technical Field

[0001] The invention belongs to the technical field of swimming nanorobots and relates to a magnetically driven hammer-shaped swimming nanorobot and a preparation method thereof. Background Art

[0002] Due to their unique autonomous motion capabilities, swimming nanorobots hold great promise for applications in biosensing, clinical diagnosis, environmental management, food testing, and other fields. Swimming nanorobots are colloidal particles that can convert other forms of energy in their environment—such as chemical, light, electrical, and magnetic—into their own mechanical motion. They are also called active colloids or swimming nanorobots. Initially, most researchers focused on designing novel asymmetric swimming nanorobots with unique motion patterns. With the rapid development of swimming nanorobots over the past decade, realizing their biomedical functions at the molecular level has become a hot topic, specifically focusing on motor-assisted load and directional transport at the micro- and nanoscale. Among various actuation methods, magnetic field actuation has attracted significant interest due to its fuel-free, non-invasive, and precisely controllable characteristics. Magnetic field guidance can be used to move magnetic micro- and nanoscale objects along predetermined paths, thereby achieving molecular-scale load and directional transport. With the continuous advancement of science and technology and the significant investment of manpower and resources, research on asymmetric structural construction, motion control, and cargo loading has made significant progress, yielding numerous significant results. Summary of the Invention

[0003] The present invention aims to solve the problems of motion control and cargo loading of existing swimming nanorobots, and provides a magnetically driven hammer-shaped swimming nanorobot with a unique hollow capsule structure and a preparation method thereof.

[0004] In order to solve the above technical problems, the present invention provides a magnetically driven hammer-like swimming nanorobot with a hollow capsule structure, wherein the hammer-like swimming nanorobot is composed of a double-layer hollow capsule skeleton of multiple polyelectrolytes (polyacrylamine hydrochloride, polystyrene sulfonate sodium salt) and peanut-shaped magnetic nanoparticles located in the capsule formed by the skeleton, wherein the length of the capsule formed by the hollow skeleton can be controlled within 1.5μm to 5.4μm, the axial diameter of the peanut-shaped magnetic nanoparticles is 0.466±0.035μm, and the radial diameter is 1.520±0.072μm; the polyelectrolyte hollow capsule skeleton is obtained by self-assembly of polyacrylamine hydrochloride and polystyrene sulfonate sodium salt in alternating layers.

[0005] The present invention provides a method for preparing a magnetically driven hammer-like swimming nanorobot, which is carried out according to the following steps:

[0006] Step 1: Add magnetic peanut-shaped α-Fe2O3 micro-nanoparticles into ultrapure water to prepare a 6 mg / mL peanut-shaped α-Fe2O3 stock solution;

[0007] Step 2: dissolving polyvinyl pyrrolidone in 1-pentanol and sonicating for 2 hours, then sequentially adding the peanut-shaped α-Fe2O3 stock solution obtained in step 1, sodium citrate, ammonium hydroxide solution, and anhydrous ethanol, and continuing sonication until a stable emulsified system is formed, followed by adding tetraethyl orthosilicate, and then standing at 22°C, centrifuging, first washing with ethanol, then washing the precipitate with water and anhydrous ethanol alternately for multiple times, and drying to obtain magnetic hammer-shaped nanoparticles;

[0008] Step 3: Use sodium chloride solution as solvent to prepare polyethyleneimine (PEI), polyacrylamine hydrochloride (PAH) and polystyrene sulfonate sodium salt (PSS) solutions respectively.

[0009] Step 4: Add the PEI solution prepared in step 3 to the hammer-shaped nanoparticles prepared in step 2, pipette repeatedly, and shake on a vortex shaker for 15 minutes, repeat 2 times to allow it to be evenly adsorbed on the nanoparticles and form a film. After the reaction is fully shaken, centrifuge again and wash with sodium chloride solution several times and centrifuge to wash away excess PEI.

[0010] Step 5: Add the PSS solution prepared in step 3, pipette repeatedly, shake for 10 minutes, repeat twice, and wash again with 0.5 mol / L sodium chloride several times and centrifuge to wash away excess unreacted PSS. Add the PAH prepared in step 3 to the above solution system, pipette repeatedly, shake for 15 minutes, repeat this operation twice, and finally wash several times with 0.5 mol / L sodium chloride and centrifuge to wash away excess unreacted PAH.

[0011] Step 6: Repeat step 5 to assemble the desired number of layers. Finally, wash the mixture several times with 0.5 mol / L sodium chloride and water, and centrifuge to remove excess unreacted substances.

[0012] Step 7: Then add hydrofluoric acid solution, and then place it on an oscillator for oscillation. After oscillation for half an hour, centrifuge it and wash it with water several times to remove excess hydrofluoric acid solution to obtain a hammer-shaped swimming nanorobot with a hollow capsule structure.

[0013] It is further defined that in step 1, the magnetic peanut-shaped α-Fe2O3 micro-nanoparticles are prepared by a hydrothermal synthesis method, specifically by the following steps:

[0014] Under magnetic stirring, 90 mL of a 6.0 mol / L sodium hydroxide aqueous solution was gradually poured into 100 mL of a 2.0 mol / L ferric chloride aqueous solution. After thorough stirring for 10 minutes, 10 mL of a 0.8 mol / L sodium sulfate solution was added and stirring was continued to ensure uniform mixing and thorough reaction of the solution. The solution was then aged at 100°C for 10 days to form α-Fe2O3 particles, which were then slowly cooled to room temperature. The product was centrifuged and the supernatant removed. The product was washed with water three times and then with a mixture of deionized water and ethanol three times to obtain micro-nano-sized peanut-shaped α-Fe2O3 particles.

[0015] It is further defined that, in step 2, the Mn of the polyvinyl pyrrolidone is 55,000.

[0016] It is further defined that in step 2, 1 g of polyvinylpyrrolidone (PVP) is dissolved in 10 mL of 1-pentanol, the amount of peanut-shaped α-Fe2O3 stock solution is 400 μL, the concentration of sodium citrate is 0.2 mol / L and the amount is 100 μL, the mass concentration of ammonium hydroxide solution is 28% and the amount is 100 μL, the amount of anhydrous ethanol is 1 mL, and the amount of tetraethyl orthosilicate (TEOS) is 40 μL.

[0017] It is further defined that in step 3, the concentration of the sodium chloride solution is 0.5 mol / L, and the concentration of the PEI solution is 2 mg / mL.

[0018] It is further defined that in step 3, the concentration of the PAH solution is 2 mg / mL.

[0019] It is further defined that in step 7, the concentration of the hydrofluoric acid solution is 1 mol / L.

[0020] The beneficial effects of the present invention are:

[0021] Polymer microcapsules are semipermeable or sealed microscopic "containers" or "packages" made of polymer shell materials that can encapsulate and protect certain substances. Microcapsules can protect substances from environmental conditions, reduce toxicity, improve the properties and performance of substances, continuously release substances into the environment, and isolate immiscible compounds.

[0022] The present invention exploits the ability of magnetic peanut-shaped nanoparticles to position and grow silicon nanorods in recessed areas, thereby synthesizing hammer-like nanoparticles. A suitable polymer is then selected as the wall material, and the principle of mutual attraction between positive and negative charges is exploited to form five double-layer polyelectrolyte films on the surface of the hammer-like nanoparticles. Etching the silicon rods results in the formation of a microcapsule-like, swimming hammer-like nanorobot. The unique microcapsules are capable of loading cargo, and the synthesized hammer-like swimming nanorobot responds to magnetic fields and can precisely deliver cargo under human control.

[0023] The artificial hammer-shaped swimming nanorobot prepared by the present invention has broad application prospects in the medical field.

[0024] In order to further understand the features and technical contents of the present invention, please refer to the following detailed description of the present invention and the accompanying drawings. However, the accompanying drawings are provided for reference and illustration only and are not intended to limit the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic flow chart of the preparation method of the magnetically driven hammer-shaped swimming nanorobot of the present invention;

[0026] Figure 2 This is a scanning electron microscope image of a hammer-shaped swimming nanorobot prepared in the first embodiment; DETAILED DESCRIPTION

[0027] The present invention will be further described below with reference to specific examples. It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

[0028] Specific implementation method 1: Combination Figure 1 Specifically, the preparation method of the magnetically driven hammer-like swimming nanorobot described in this embodiment is carried out according to the following steps:

[0029] 1. Preparation of magnetic peanut-shaped α-Fe2O3 micro-nanoparticles:

[0030] Using a hydrothermal synthesis method, 90 mL of a pre-prepared sodium hydroxide solution (6.0 mol / L) was gradually poured into 100 mL of a 2.0 mol / L ferric chloride solution under magnetic stirring. After thorough stirring for 10 minutes, 10 mL of a 0.8 mol / L sodium sulfate solution was added and stirred continuously to ensure uniform mixing and complete reaction. The solution was then transferred to a 250 mL blue-mouthed bottle. The bottle containing the gelled ferric hydroxide was then placed in a laboratory oven preheated at 100°C for 10 days to form α-Fe₂O₃ microparticles. After the reaction was complete, the bottle was slowly cooled to room temperature with hot water. The product was centrifuged, the supernatant removed, and washed three times with water. Finally, it was washed three times with a mixture of deionized water and ethanol to obtain peanut-shaped micro- and nano-sized α-Fe₂O₃ particles with a unique structure.

[0031] 2. Preparation of magnetic hammer-shaped nanoparticles:

[0032] Using an electronic analytical balance, 1g of polyvinylpyrrolidone (PVP, Mn = 55,000) was dissolved in 10mL of 1-pentanol. Repeated sonication was performed for 2 hours. Then, 400μL of the synthesized peanut-shaped α-Fe2O3 stock solution, 100μL of sodium citrate (0.2mol / L), 100μL of 28% ammonium hydroxide solution, and 1000mL of anhydrous ethanol were added in sequence. Ultrasonication was continued until the mixture formed a stable emulsion. Subsequently, 50μL of tetraethyl orthosilicate (TEOS) was added. In the presence of TEOS, silicon nanorods grew within the depressions of the peanut-shaped magnetic nanoparticles. The mixture was allowed to stand at 22°C for 2 hours. The product was collected by centrifugation and washed several times with alternating mixtures of water and ethanol. Finally, the product was dried at 80°C for 12 hours to obtain a dry sample, which was then stored at room temperature.

[0033] 3. Preparation of hammer-shaped swimming nanorobots with hollow capsule structures:

[0034] 1. Use the pre-prepared 0.5 mol / L sodium chloride solution as the solvent to prepare 2 mg / mL polyethyleneimine (PEI), 2 mg / mL polyacrylamine hydrochloride (PAH) and 2 mg / mL polystyrene sulfonate sodium salt (PSS) solutions respectively.

[0035] 2. Add the prepared PEI solution to the hammer-shaped nanoparticles prepared in step 2. Pipette repeatedly and shake on a vortex shaker for 15 minutes. Repeat twice to ensure uniform adsorption onto the nanoparticles and film formation. After sufficient shaking, centrifuge again and rinse several times with 0.5 mol / L sodium chloride solution and centrifuge to remove excess PEI.

[0036] 3. Then add the prepared 2 mg / mL PSS solution, pipette repeatedly, and shake for 10 minutes. Repeat twice. Wash several times with 0.5 mol / L sodium chloride and centrifuge to remove excess unreacted PSS. Add the prepared PAH to the above solution, pipette repeatedly, shake for 15 minutes, and repeat this procedure twice. Finally, wash several times with 0.5 mol / L sodium chloride and centrifuge to remove excess unreacted PAH.

[0037] 4. Repeat step 3 for 5 times. Finally, wash with 0.5 mol / L sodium chloride several times, wash with water several times, and centrifuge to remove excess unreacted substances.

[0038] 5. Then, a 1 mol / L hydrofluoric acid solution was diluted and added to the assembled solution, which was then placed on an oscillator for oscillation. After oscillation for half an hour, the solution was centrifuged and washed with water several times to remove excess hydrofluoric acid solution. Then, a hammer-shaped swimming nanorobot with a hollow capsule structure (such as Figure 2 shown).

[0039] This embodiment is simple and easy to implement, with stable process, good repeatability, and is convenient for mass production. The prepared hammer-shaped swimming nanorobot not only has good transportability and biocompatibility, but also has good load function. It has broad application prospects in the biomedical field, especially in controlling drug release and clinical diagnosis.

Claims

1. A method for preparing a magnetically driven hammer-like swimming nanorobot, characterized in that: The method is carried out according to the following steps: Step 1: adding magnetic peanut-shaped α-Fe2O3 micro-nanoparticles into ultrapure water to prepare a peanut-shaped α-Fe2O3 stock solution; Step 2: dissolving polyvinyl pyrrolidone in 1-pentanol and sonicating for 2 hours, then sequentially adding the peanut-shaped α-Fe2O3 stock solution obtained in step 1, sodium citrate, ammonium hydroxide solution, and anhydrous ethanol, and continuing sonication until a stable emulsified system is formed, followed by adding tetraethyl orthosilicate, and then standing at 22°C, centrifuging, first washing with ethanol, then washing the precipitate with water and anhydrous ethanol alternately for multiple times, and drying to obtain magnetic hammer-shaped nanoparticles; Step 3: Use sodium chloride solution as solvent to prepare polyethyleneimine (PEI), polyacrylamine hydrochloride (PAH) and polystyrene sulfonate sodium salt (PSS) solutions respectively. Step 4: Add the PEI solution prepared in step 3 to the hammer-shaped nanoparticles prepared in step 2, pipette repeatedly, and shake on a vortex shaker for 15 minutes, repeat 2 times to allow it to be evenly adsorbed on the nanoparticles and form a film. After the reaction is fully shaken, centrifuge again and wash with sodium chloride solution several times and centrifuge to wash away excess PEI. Step 5: Add the PSS solution prepared in step 3, pipette repeatedly, shake for 10 minutes, repeat twice, and wash again with 0.5 mol / L sodium chloride several times and centrifuge to wash away excess unreacted PSS. Add the PAH prepared in step 3 to the above solution system, pipette repeatedly, shake for 15 minutes, repeat this operation twice, and finally wash several times with 0.5 mol / L sodium chloride and centrifuge to wash away excess unreacted PAH. Step 6: Repeat step 5 to assemble the desired number of layers. Finally, wash the mixture several times with 0.5 mol / L sodium chloride and water, and centrifuge to remove excess unreacted substances. Step 7: Then add hydrofluoric acid solution, and then place it on an oscillator for oscillation. After oscillation for half an hour, centrifuge it and wash it with water several times to remove excess hydrofluoric acid solution to obtain a hammer-shaped swimming nanorobot with a hollow capsule structure.

2. The method according to claim 1, characterized in that In step 1, the concentration of the peanut-shaped α-Fe2O3 stock solution is 6 mg / mL, and the magnetic peanut-shaped α-Fe2O3 micro-nanoparticles are prepared by a hydrothermal synthesis method, specifically by the following steps: Under magnetic stirring, 90 mL of a 6.0 mol / L sodium hydroxide aqueous solution was gradually poured into 100 mL of a 2.0 mol / L ferric chloride aqueous solution. After thorough stirring for 10 minutes, 10 mL of a 0.8 mol / L sodium sulfate solution was added and stirring was continued to ensure uniform mixing and thorough reaction of the solution. The solution was then aged at 100°C for 10 days to form α-Fe2O3 particles, which were then slowly cooled to room temperature. The product was centrifuged and the supernatant removed. The product was washed with water three times and then with a mixture of deionized water and ethanol three times to obtain micro-nano-sized peanut-shaped α-Fe2O3 particles.

3. The method according to claim 1, characterized in that In step 2, the Mn of polyvinyl pyrrolidone is 55,000.

4. The method according to claim 1, characterized in that In step 2, 1 g of polyvinylpyrrolidone (PVP) was dissolved in 10 mL of 1-pentanol, 400 μL of peanut-shaped α-Fe2O3 stock solution was used, the concentration of sodium citrate was 0.2 mol / L and the amount was 100 μL, the mass concentration of ammonium hydroxide solution was 28% and the amount was 100 μL, the amount of anhydrous ethanol was 1 mL, and the amount of tetraethyl orthosilicate (TEOS) was 40 μL.

5. The method according to claim 1, characterized in that: In step 3, the concentration of the sodium chloride solution is 0.5 mol / L, and the concentration of the PEI solution is 2 mg / mL.

6. The method according to claim 1, characterized in that In step 3, the concentration of the PAH solution is 2 mg / mL.

7. The method according to claim 1, characterized in that In step 3, the concentration of the PSS solution is 2 mg / mL.

8. The method according to claim 1, characterized in that: In step 7, the concentration of the hydrofluoric acid solution is 1 mol / L.

9. A magnetically driven hammer-shaped swimming nanorobot prepared by the method according to any one of claims 1 to 8.

10. The hammer-shaped swimming nanorobot according to claim 9, characterized in that: It is composed of a multi-layer polyelectrolyte hollow capsule skeleton and peanut-shaped magnetic nanoparticles located in the capsule formed by the skeleton. The length of the capsule formed by the hollow capsule skeleton can be controlled within the range of 1.5 μm to 5.4 μm, the axial diameter of the peanut-shaped magnetic nanoparticles is 0.46±0.035 μm, and the radial diameter is 1.52±0.072 μm; the polyelectrolyte hollow capsule skeleton is obtained by alternating layer-by-layer self-assembly of polyacrylamine hydrochloride and sodium polystyrene sulfonate.

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