Silicon dioxide-ferroferric oxide magnetic particles and their preparation method and application

Abstract

The present invention discloses a method for preparing silicon dioxide-iron tetroxide magnetic particles, comprising the following steps: A. functionalizing a porous silicon dioxide film to obtain a porous silicon dioxide film with functional groups on the surface; B. dissolving anhydrous ferric chloride in water to obtain a ferric chloride solution; soaking the porous silicon dioxide film with functional groups on the surface in the ferric chloride solution, taking it out and heating it to obtain a porous silicon dioxide film with ferric chloride hexahydrate attached to the surface; C. laser processing to obtain a porous silicon dioxide film with a silicon dioxide-iron tetroxide precursor attached to the surface; D. peeling and ultrasonically oscillating the silicon dioxide-iron tetroxide precursor on the surface of the porous silicon dioxide film to obtain silicon dioxide-iron tetroxide magnetic particles. A method for preparing silicon dioxide-iron tetroxide magnetic particles proposed by the present invention, the obtained silicon dioxide-iron tetroxide magnetic particles have high suspension stability and strong adsorption capacity.

Description

Technical Field

[0001] The present invention relates to the technical field of magnetic particles, and in particular to silicon dioxide-ferroferric oxide magnetic particles and a preparation method and application thereof. Background Art

[0002] Swarm micro-nano robots are microrobots assembled from magnetic particles under the influence of a magnetic field. Their hallmarks include significantly improved loading capacity and task execution efficiency. These robots have shown broad application potential in fields such as medicine, environmental monitoring, and precision manufacturing. In medicine in particular, swarm micro-nano robots can precisely perform tasks such as targeted drug delivery, cell manipulation, and tissue repair, significantly advancing minimally invasive treatments and biomedical innovations. Among various actuation methods, magnetic actuation technology has become a focus of current research due to its advantages of remote control, precise control, and efficient energy transmission.

[0003] As an important ferromagnetic material, ferroferric oxide has shown significant application prospects in the field of magnetically driven cluster micro-nano robots. Its strong paramagnetism and good magnetic responsiveness make the material exhibit excellent controllability under the action of an external magnetic field. In addition, both ferroferric oxide and silicon dioxide have good biocompatibility and safety, can exist stably in the body, and can be excreted from the body through metabolic pathways, thereby minimizing the impact on cells and tissues. Therefore, the industry has emerged with the use of silica-ferroferric oxide magnetic particles composed of ferroferric oxide and silicon dioxide, which are magnetized under the action of a magnetic field to obtain magnetically driven cluster micro-nano robots. The performance of magnetically driven cluster micro-nano robots depends on the performance of silica-ferroferric oxide magnetic particles, making silica-ferroferric oxide magnetic particles a key material for the preparation of magnetically driven cluster micro-nano robots.

[0004] The Chinese invention patent with publication number CN110451581A discloses a method for preparing double-layer ferroferric oxide @ silicon dioxide magnetic composite nanoparticles, which uses an improved Stober method to prepare double-layer ferroferric oxide @ silicon dioxide magnetic composite nanoparticles. However, since the prepared magnetic composite nanoparticles have a dense structure and lack porosity, their effective contact area with the liquid is limited, resulting in a higher interfacial energy, which makes the particles easy to settle in the liquid, affecting the suspension stability of the magnetic composite nanoparticles in the solution. As a result, the magnetically driven cluster micro-nano robot prepared on this basis is prone to near-wall effect (referring to easy sedimentation in the liquid or close to the container wall) when moving in the solution, reducing the degree of freedom of movement and control accuracy, thereby affecting precise positioning. At the same time, the dense structure leads to a limited specific surface area of ​​the particles, which limits the adsorption capacity of drugs, thereby limiting the drug loading capacity of the magnetically driven cluster micro-nano robot.

[0005] The Chinese invention patent publication number CN110002452A discloses a method for preparing micron-sized hollow magnetic silica microspheres. The method first uses the Stober method to prepare hollow silica microspheres, then performs surface modification, and then uses the surface-modified hollow silica microspheres to adsorb Fe in a salt solution. 3+ and Fe 2+ , Fe 3+ and Fe 2+ Magnetic ferroferric oxide nanoparticles are deposited on the outer and inner surfaces of hollow silica microspheres to obtain micron-sized hollow magnetic silica microspheres. However, during this process, ferroferric oxide easily precipitates directly inside the hollow pores of the hollow silica microspheres, causing the hollow pores to be blocked. This makes it difficult for the resulting micron-sized hollow magnetic silica microspheres to adsorb drugs, thereby weakening the drug-carrying capacity of the magnetically driven cluster micro-nanorobot constructed with them. In addition, this preparation method is relatively complex, which easily increases the difficulty of preparation.

[0006] In summary, existing silica-ferroferric oxide magnetic particles generally have problems such as complex preparation methods, poor suspension stability and weak adsorption capacity. Summary of the Invention

[0007] One of the objectives of the present invention is to provide a method for preparing silica-ferroferric oxide magnetic particles. The preparation method is simple and has a fast processing speed. The obtained silica-ferroferric oxide magnetic particles not only have high suspension stability but also have strong adsorption capacity, thereby overcoming the shortcomings of the existing technology.

[0008] The second object of the present invention is to provide a silicon dioxide-ferroferric oxide magnetic particle, which not only has high suspension stability but also has strong adsorption capacity.

[0009] The third purpose of the present invention is to provide an application of silica-ferroferric oxide magnetic particles to prepare magnetically driven cluster micro-nano robots. The obtained magnetically driven cluster micro-nano robots have a drug loading rate of up to 80-85%. They not only have strong drug loading capacity but also have precise positioning, which can greatly meet the needs of practical applications.

[0010] To achieve this object, the present invention adopts the following technical solutions:

[0011] A method for preparing silicon dioxide-ferroferric oxide magnetic particles comprises the following steps:

[0012] A. preparing a porous silica film; performing a functional treatment on the porous silica film to obtain a porous silica film having functional groups on its surface; wherein the functional groups are used to bind to drug molecules and to form charged groups in the solution;

[0013] B. dissolving anhydrous ferric chloride in water and stirring to obtain a ferric chloride solution; immersing the porous silica film with functional groups on the surface in step A in the ferric chloride solution, removing the film and heating it to obtain a porous silica film with ferric chloride hexahydrate attached to the surface;

[0014] C. laser processing the porous silica film with ferric chloride hexahydrate attached to the surface in step B to obtain a porous silica film with a silica-ferroferric oxide precursor attached to the surface;

[0015] D. peeling off the silica-ferroferric oxide precursor on the surface of the porous silica film in step C to obtain a silica-ferroferric oxide precursor; and ultrasonically vibrating the silica-ferroferric oxide precursor to obtain silica-ferroferric oxide magnetic particles.

[0016] Furthermore, in step A, the preparation method of the porous silica film is specifically as follows:

[0017] A silica precursor solution is coated on the surface of a substrate, and a substrate with silica gel attached to the surface is obtained after laser processing;

[0018] placing the substrate with the silica gel attached to the surface into a mixed solution of ethanol and water to obtain a substrate with a porous silica film attached to the surface;

[0019] peeling off the porous silica film on the surface of the substrate to obtain a porous silica film;

[0020] The raw materials of the silicon dioxide precursor solution include a template, a tetraethyl orthosilicate solution and a hydrochloric acid solution, and the mixing ratio of the template, the tetraethyl orthosilicate solution and the hydrochloric acid solution is (0.1-0.3):1:(0.001-0.005) calculated by volume.

[0021] The raw materials of the tetraethyl orthosilicate solution include tetraethyl orthosilicate, anhydrous ethanol and water, and calculated according to the molar ratio, the mixing ratio of the tetraethyl orthosilicate, the anhydrous ethanol and the water is 1: (2 to 6): (8 to 12).

[0022] Furthermore, in step A, the functionalization treatment is an amination treatment or a carboxylation treatment;

[0023] The functional group includes any one of an amino group and a carboxyl group.

[0024] Furthermore, the specific method of the amination treatment is: performing laser processing on the porous silica film to obtain a porous silica film with increased surface activity; applying an amination precursor solution on the surface of the porous silica film with increased surface activity, and heating at 50 to 60° C. for 0.5 to 0.6 h to obtain an amination-treated porous silica film;

[0025] The raw materials of the amination precursor solution include 3-aminopropyltriethoxysilane solution and acetic acid solution; the raw materials of the 3-aminopropyltriethoxysilane solution include 3-aminopropyltriethoxysilane, anhydrous ethanol and water.

[0026] Furthermore, the specific method of the carboxylation treatment is: performing laser processing on the porous silica film to obtain a porous silica film with increased surface activity; coating the surface of the porous silica film with increased surface activity with a carboxylation precursor solution, and heating it at 50 to 60° C. for 0.5 to 0.6° C. to obtain a carboxylation-treated porous silica film;

[0027] Wherein, the raw materials of the carboxylation precursor solution include chloroacetic acid and water.

[0028] Furthermore, in step B, the mixing ratio of the anhydrous ferric chloride to the water is 1:(2-4) calculated by mass ratio;

[0029] In step B, the heating temperature is 60-80°C.

[0030] Furthermore, in step C, the laser wavelength of the laser processing is 350-360 nm, and the laser power is 10-15 W.

[0031] Furthermore, in step D, the ultrasonic oscillation time is 3 to 5 minutes and the frequency is 30 to 40 kHz.

[0032] A silicon dioxide-ferroferric oxide magnetic particle is prepared using the above-mentioned method for preparing a silicon dioxide-ferroferric oxide magnetic particle.

[0033] An application of silica-ferroferric oxide magnetic particles in the preparation of magnetically driven clustered micro-nano robots, using the aforementioned silica-ferroferric oxide magnetic particles, and an application method comprising: dispersing the silica-ferroferric oxide magnetic particles in a polyvinyl pyrrolidone solution, applying a rotating magnetic field, and magnetizing to obtain a magnetically driven clustered micro-nano robot;

[0034] Wherein, calculated by mass percentage, the content of polyvinyl pyrrolidone in the polyvinyl pyrrolidone solution is 2-5%;

[0035] The shape of the magnetically driven cluster micro-nano robot is circular or elliptical, and the drug loading rate is 80-85%.

[0036] The technical solution provided by the present invention can have the following beneficial effects:

[0037] 1. By making the porous silica film have a porous structure, the silica-iron tetroxide magnetic particles also have a porous structure, and the porous structure of the silica-iron tetroxide magnetic particles increases its contact area with the liquid and reduces the interfacial energy, which is conducive to maintaining a uniform dispersion state, preventing phase separation and sedimentation, and thus helping to improve its suspension stability. In addition, the pores in the porous structure can retain liquid to form a liquid-solid composite system, and the retained liquid further reduces the effective density of the silica-iron tetroxide magnetic particles, making it closer to the density of the liquid, thereby increasing the suspension stability. It should be noted that the porosity and pore size of the porous silica film in this scheme can be adjusted, so that the density of the silica-iron tetroxide magnetic particles finally obtained can be adjusted according to the actual application scenario, which is also conducive to enhancing the suspension stability. Furthermore, through functionalization treatment, the silica-iron tetroxide magnetic particles finally obtained are introduced with functional groups (such as -NH2 and / or -COOH), and the functional groups are easily protonated or ionized in the liquid to form charged groups (such as -NH3 + and / or -COO - ), so that the silicon dioxide-ferroferric oxide magnetic particles produce electrostatic repulsion in the liquid, preventing the particles from agglomerating and settling, which is also beneficial to increasing its suspension stability.

[0038] 2. Silica has the characteristic that is porous and has high specific surface area, makes the silicon dioxide-iron tetroxide magnetic particles finally obtained have higher adsorption capacity to medicine, thus improves adsorption capacity. Meanwhile, the porosity and pore size of porous silica film are adjustable in the present application, and appropriate porosity and pore size can ensure that target molecule can smoothly enter pore and be effectively adsorbed, and are also conducive to improving adsorption capacity. In addition, the present technical solution is processed by functionalization, so that the silicon dioxide-iron tetroxide magnetic particles finally obtained have functional groups, and functional groups can form stable complexes with drug molecules (such as DNA, RNA, antibodies or chemotherapeutics), are conducive to improving adsorption capacity. In addition, functionalization not only introduces functional groups, but also increases the roughness of the silicon dioxide-iron tetroxide magnetic particles finally obtained surface, thus increases specific surface area, and larger specific surface area provides more adsorption sites for drug molecules, and then improves adsorption capacity. DETAILED DESCRIPTION

[0039] This technical solution provides a method for preparing silicon dioxide-ferroferric oxide magnetic particles, comprising the following steps:

[0040] A. preparing a porous silica film; performing a functional treatment on the porous silica film to obtain a porous silica film having functional groups on its surface; wherein the functional groups are used to bind to drug molecules and to form charged groups in the solution;

[0041] B. dissolving anhydrous ferric chloride in water and stirring to obtain a ferric chloride solution; immersing the porous silica film with functional groups on the surface in step A in the ferric chloride solution, removing the film and heating it to obtain a porous silica film with ferric chloride hexahydrate attached to the surface;

[0042] C. laser processing the porous silica film with ferric chloride hexahydrate attached to the surface in step B to obtain a porous silica film with a silica-ferroferric oxide precursor attached to the surface;

[0043] D. peeling off the silica-ferroferric oxide precursor on the surface of the porous silica film in step C to obtain a silica-ferroferric oxide precursor; and ultrasonically vibrating the silica-ferroferric oxide precursor to obtain silica-ferroferric oxide magnetic particles.

[0044] Prior art uses a modified Stober method to prepare double-layered ferroferric oxide and silica magnetic composite nanoparticles. However, the resulting magnetic composite nanoparticles have a dense structure and lack porosity, resulting in poor suspension stability and weak adsorption capacity. Furthermore, prior art uses the Stober method and deposition methods to prepare silica-ferroferric oxide, which not only complicates the preparation process but also results in poor suspension stability and weak adsorption capacity.

[0045] To overcome the complex preparation methods and weak adsorption capacity inherent in existing technologies, this technical solution proposes a method for preparing silica-ferroferric oxide magnetic particles. The method comprises four steps: A (functionalization), B (immersion in ferric chloride solution), C (laser processing), and D (exfoliation). The resulting silica-ferroferric oxide magnetic particles exhibit not only high suspension stability but also strong adsorption capacity. Furthermore, this method is simple and the processing speed is fast, improving production efficiency.

[0046] Specifically, the present technical solution is made to have a porous structure by making the porous silica film have a porous structure, so that the silica-ferroferric oxide magnetic particles also have a porous structure, and the porous structure of the silica-ferroferric oxide magnetic particles increases its contact area with the liquid, reduces the interfacial energy, thereby being conducive to maintaining a uniform dispersion state, preventing phase separation and sedimentation, thereby being conducive to improving its suspension stability. In addition, the pores in the porous structure can retain liquid to form a liquid-solid composite system, and the retained liquid further reduces the effective density of the silica-ferroferric oxide magnetic particles, making it closer to the density of the liquid, thereby increasing suspension stability. It should be noted that the porosity and pore size of the porous silica film in this solution are both adjustable, so that the density of the silica-ferroferric oxide magnetic particles finally obtained can be adjusted according to the actual application scenario, which is also conducive to enhancing suspension stability. Furthermore, through functionalization treatment, the final silica-ferroferric oxide magnetic particles are introduced with functional groups (such as -NH2 and / or -COOH), and the functional groups are easily protonated or ionized in the liquid to form charged groups (such as -NH3 + and / or -COO - ), thereby causing the silica-ferroferric oxide magnetic particles to generate electrostatic repulsion in the liquid, preventing particle agglomeration and sedimentation, and also helping to increase their suspension stability. That is, through the aforementioned multiple effects, the present application ensures that the silica-ferroferric oxide magnetic particles obtained using this technical solution have suspension stability.

[0047] Further, the silica of the present technical solution has the characteristic of being porous and having a high specific surface area, so that the silica-iron tetroxide magnetic particles finally obtained have a higher adsorption capacity to medicine, thereby improving adsorption capacity. Meanwhile, the porosity and pore size of the porous silica film in the present application are adjustable, and appropriate porosity and pore size can ensure that the target molecule can smoothly enter the pore and be effectively adsorbed, which is also conducive to improving adsorption capacity. In addition, the present technical solution is processed by functionalization so that the silica-iron tetroxide magnetic particles finally obtained have functional groups, and functional groups can form stable complexes with drug molecules (such as DNA, RNA, antibodies or chemotherapy drugs), which is conducive to improving adsorption capacity. In addition, functionalization not only introduces functional groups, but also increases the roughness of the silica-iron tetroxide magnetic particles finally obtained, thereby increasing specific surface area, and larger specific surface area provides more adsorption sites for drug molecules, thereby improving adsorption capacity. In summary, the present application is processed by the above-mentioned many aspects so that silica-iron tetroxide magnetic particles have extremely strong adsorption capacity.

[0048] It should be noted that although the silica layer is located inside the silica-ferroferric oxide magnetic particles obtained after laser processing, the internal silica layer still retains the functional groups and porous structure introduced by the functionalization treatment, so that its adsorption and suspension capabilities are still maintained or enhanced.

[0049] Furthermore, this technical solution only requires two basic raw materials and can produce the target product through simple processing, which not only reduces costs but also enhances the controllability of the operation, laying a solid foundation for subsequent industrial applications. During the preparation process, the application of laser processing technology has shown the following advantages: (1) Laser processing has achieved a significant increase in processing speed and significantly improved production efficiency; (2) The stability of laser energy is conducive to ensuring the performance consistency of the prepared silicon dioxide-iron tetroxide magnetic particles, thereby improving the performance stability of the product.

[0050] More specifically, because the ferric chloride solution itself contains a large amount of water, laser processing easily leads to laser energy dissipation, making it impossible to produce a highly consistent silica-ferroferric oxide precursor. Therefore, this technical solution adopts a heating method to cause the ferric chloride solution to precipitate ferric chloride hexahydrate on the surface of the porous silica film. The ferric chloride hexahydrate is then processed using a laser to produce a highly consistent silica-ferroferric oxide precursor.

[0051] During the laser processing step (step B), the laser light causes a redox reaction in ferric chloride hexahydrate to produce ferroferric oxide nanoparticles. During this process, the ferroferric oxide magnetic particles tightly bond with the porous silica film with functional groups on its surface, forming a silica-ferroferric oxide precursor.

[0052] It should be noted that during the laser processing process, the laser does not completely penetrate the porous silica film with functional groups on the surface. Only a portion of the porous silica film with functional groups on the surface combines with the ferroferric oxide magnetic particles converted from ferric chloride hexahydrate. The other portion of the porous silica film with functional groups on the surface still exists in its own form, so that the porous silica film with functional groups on the surface can be used as a carrier to carry the silica-ferroferric oxide precursor, and can also be used as a raw material to participate in the preparation of the silica-ferroferric oxide precursor, greatly simplifying the preparation process, saving raw materials and reducing costs. In addition, during the laser processing process, the laser beam will generate local high temperature in the action area, so that the bonding area of ​​ferroferric oxide and silica will be locally heated, thereby achieving a tight fit.

[0053] Finally, the silica-ferroferric oxide precursor on the surface of the porous silica film in step C is stripped to obtain the silica-ferroferric oxide precursor, and then the silica-ferroferric oxide precursor is ultrasonically vibrated to obtain silica-ferroferric oxide magnetic particles. The stripping method is simple. It should be noted that in step D, the specific method of the stripping is: scraping the silica-ferroferric oxide precursor on the surface of the porous silica film with a blade.

[0054] It should be noted that, in the prior art, graphene-ferroferric oxide magnetic particles are generally used to prepare magnetically driven cluster micro-nano robots, but in this technical solution, graphene-ferroferric oxide magnetic particles cannot replace silicon dioxide-ferroferric oxide magnetic particles. The specific reasons are as follows: (1) The surface of graphene lacks natural hydroxyl groups, which makes its surface chemical reaction activity poor and difficult to modify it directly through chemical methods of carboxylation and amination; (2) Compared with silicon dioxide, graphene has poor biocompatibility and is difficult to be directly excreted from the body through metabolic pathways. As a result, the magnetically driven cluster micro-nano robots prepared using graphene-ferroferric oxide magnetic particles are more suitable for use in the electronics or catalysis fields, rather than in the biomedical field.

[0055] Preferably, the laser processing step in step C further includes a drying step, specifically: soaking the porous silica film with the silica-ferroferric oxide precursor attached to the surface in water, and then drying it at a temperature of 75 to 85°C.

[0056] In one embodiment of the present technical solution, a porous silica film with a silica-ferroferric oxide precursor attached to its surface is immersed in water to remove the ferric chloride hexahydrate remaining on the surface of the porous silica film, and then dried at a temperature of 75 to 85°C to remove the moisture, so that the silica-ferroferric oxide precursor can be more easily peeled off from the porous silica film, thereby improving production efficiency.

[0057] Further description, in step A, the preparation method of the porous silica film is specifically as follows:

[0058] A silica precursor solution is coated on the surface of a substrate, and a substrate with silica gel attached to the surface is obtained after laser processing;

[0059] placing the substrate with the silica gel attached to the surface into a mixed solution of ethanol and water to obtain a substrate with a porous silica film attached to the surface;

[0060] peeling off the porous silica film on the surface of the substrate to obtain a porous silica film;

[0061] The raw materials of the silicon dioxide precursor solution include a template, a tetraethyl orthosilicate solution and a hydrochloric acid solution, and the mixing ratio of the template, the tetraethyl orthosilicate solution and the hydrochloric acid solution is (0.1-0.3):1:(0.001-0.005) calculated by volume.

[0062] The raw materials of the tetraethyl orthosilicate solution include tetraethyl orthosilicate, anhydrous ethanol and water, and calculated according to the molar ratio, the mixing ratio of the tetraethyl orthosilicate, the anhydrous ethanol and the water is 1: (2 to 6): (8 to 12).

[0063] This technical solution utilizes the hydrolysis reaction of tetraethyl orthosilicate with water in the acidic environment provided by hydrochloric acid to generate silanols (Si-OH). The silanols further condense to form a Si-O-Si network structure, thereby forming silica gel on the substrate surface, resulting in a substrate with silica gel attached to the surface. Simultaneously, a template (such as a surfactant) forms micelles or self-assembled structures in the solution, providing a foundation for the subsequent formation of a porous structure. The template, as an amphiphilic molecule, has a long hydrophobic chain that is soluble in ethanol and a hydrophilic head that is soluble in water. Therefore, placing the substrate with silica gel attached in a mixed solution of ethanol and water removes the template, leaving gaps occupied by the template and forming a uniform porous structure in the silica gel, resulting in a substrate with a porous silica film attached to the surface. Finally, the porous silica film is obtained by peeling off the porous silica film from the substrate surface. This method is simple to prepare, and the use of laser processing can accelerate the hydrolysis and polycondensation reactions of tetraethyl orthosilicate, thereby improving production efficiency.

[0064] The porosity and pore size of porous silica films are not only related to the mixing ratio of the template and tetraethyl orthosilicate solution in the silica precursor solution, but also closely related to the mixing ratio of tetraethyl orthosilicate, anhydrous ethanol, and water in the tetraethyl orthosilicate solution. Specifically, if the template ratio is too high, the porosity will be low, the pore size will be too large, and the pore distribution will be uneven. If the template ratio is too low, the porosity will be high, the pore size will be too small, and the pore structure will be unstable and prone to collapse. If the tetraethyl orthosilicate ratio is too high, the density of the porous silica film will be too high, the pores will be difficult to form, and the size will be too small. If the tetraethyl orthosilicate ratio is too low, not only will the pore size of the porous silica film be too large, but it will also cause the density of the porous silica film to be too low, and the pore structure will be prone to collapse.

[0065] Therefore, the present technical solution limits the ratio of the template, tetraethyl orthosilicate solution and hydrochloric acid solution in the silica precursor solution, as well as the ratio of tetraethyl orthosilicate, anhydrous ethanol and water in the tetraethyl orthosilicate solution, thereby ensuring that the porosity and pore size of the porous silica film are appropriate, thereby achieving controllable porosity and pore size.

[0066] In addition, the ratio of each component in the tetraethyl orthosilicate solution has a significant effect on the film quality, as shown in the following: (1) If the ethanol ratio is too high, the hydrolysis rate will be reduced, resulting in decreased film stability; if the ethanol ratio is too low, the solution viscosity will be increased, resulting in uneven coating and difficulty in forming a high-quality film; if the water ratio is too high, the hydrolysis and polycondensation rate of tetraethyl orthosilicate will be accelerated, resulting in rough product and uneven pore distribution; if the water ratio is too low, the hydrolysis rate will be reduced, resulting in an incomplete product structure and poor pore stability. Therefore, by optimizing the ratio of each component in the tetraethyl orthosilicate solution, the porosity and pore size can be precisely controlled while ensuring the quality of the porous silica film.

[0067] Preferably, the concentration of hydrochloric acid in the hydrochloric acid solution is 0.01 to 0.03 mol / L.

[0068] By limiting the concentration of hydrochloric acid in the hydrochloric acid solution, it is helpful to ensure its catalytic effect.

[0069] It should be noted that the template agent may be hexadecyltrimethylammonium bromide, sodium lauryl sulfate, etc., and the specific type is not limited here. The substrate may be a glass substrate, and the specific type is also not limited here.

[0070] Further, in step A, the functionalization treatment is an amination treatment or a carboxylation treatment;

[0071] The functional group includes any one of an amino group and a carboxyl group.

[0072] The porous silica film is subjected to an amination or carboxylation treatment, resulting in a product with amino or carboxyl groups on its surface. These amino and carboxyl groups not only improve the hydrophilicity and biocompatibility of the product, making it suitable for biomedical applications, but also interact with a variety of substances, enhancing the adsorption properties of the product, making it suitable for environmental protection applications such as wastewater treatment and gas purification. Therefore, this technical solution, which subjects the porous silica film to an amination or carboxylation treatment, is beneficial for improving the product's performance and broadening its application areas.

[0073] Further, the specific method of the amination treatment is as follows: laser processing the porous silica film to obtain a porous silica film with increased surface activity; coating the surface of the porous silica film with increased surface activity with an amination precursor solution, and heating it at 50 to 60° C. for 0.5 to 0.6 h to obtain the amination-treated porous silica film;

[0074] The raw materials of the amination precursor solution include 3-aminopropyltriethoxysilane solution and acetic acid solution; the raw materials of the 3-aminopropyltriethoxysilane solution include 3-aminopropyltriethoxysilane, anhydrous ethanol and water.

[0075] Through laser processing, the local high-temperature thermal effect and photochemical effect of the laser are used to locally break the molecular bonds on the surface of the silica to form silanol (Si-OH) groups. Silanol is an active site on the surface of porous silica films, which can enhance the surface activity of porous silica films and provide more favorable conditions for subsequent amination. In addition, the laser processing activation step is more efficient than traditional chemical methods and can significantly increase the number of active sites on the silica surface in a short period of time, providing more favorable conditions for subsequent amination treatment.

[0076] Furthermore, the amination precursor solution is prepared by mixing a 3-aminopropyltriethoxysilane solution and an acetic acid solution in a certain ratio. 3-aminopropyltriethoxysilane is a compound containing amino groups and ethoxysilane. Under the catalytic action of acetic acid, it can react with the silanol groups on the surface of the porous silica film to obtain an amination-treated porous silica film.

[0077] It should be noted that if the heating temperature is too high, the 3-aminopropyltriethoxysilane molecules will easily undergo self-polymerization reaction to generate insoluble polysilane substances, affecting the uniformity of the product surface; if the heating temperature is too low, the amination reaction rate will be reduced, resulting in insufficient degree of amination, affecting the performance of the product. Therefore, the present technical solution limits the heating temperature, which is beneficial to prevent the self-polymerization reaction of the 3-aminopropyltriethoxysilane molecules while improving the reaction rate. In addition, due to the high surface activity of the porous silica film after laser processing, the heating reaction time only needs to be 0.5 to 0.6 hours to complete the amination treatment, which is beneficial to improve production efficiency.

[0078] Preferably, calculated by volume ratio, the mixing ratio of the 3-aminopropyltriethoxysilane solution to the acetic acid solution is 1:(0.01-0.05);

[0079] Calculated by molar ratio, the mixing ratio of the 3-aminopropyltriethoxysilane, the anhydrous ethanol and the water is 1: (8-12): (10-15);

[0080] The concentration of acetic acid in the acetic acid solution is 0.01-0.03 mol / L.

[0081] If the proportion of 3-aminopropyltriethoxysilane solution in the amination precursor solution is too high, the excess 3-aminopropyltriethoxysilane molecules in the amination precursor solution will undergo self-polymerization to generate granular substances, affecting the quality of the product; if the proportion of 3-aminopropyltriethoxysilane solution in the amination precursor solution is too low, the degree of amination will be insufficient, affecting the performance of the product.

[0082] Further, the specific method of the carboxylation treatment is as follows: laser processing the porous silica film to obtain a porous silica film with increased surface activity; coating the surface of the porous silica film with increased surface activity with a carboxylation precursor solution, and heating it at 50 to 60° C. for 0.5 to 0.6° C. to obtain a carboxylation-treated porous silica film;

[0083] Wherein, the raw materials of the carboxylation precursor solution include chloroacetic acid and water.

[0084] The carboxylation precursor solution is a mixture of chloroacetic acid and water in a specific ratio. Chloroacetic acid reacts with the silanol groups on the surface of the porous silica film to produce a carboxylated porous silica film. Furthermore, due to the high surface activity of the laser-processed porous silica film, the heating reaction time is only 0.5 to 0.6 hours to complete the carboxylation treatment.

[0085] Preferably, calculated by volume ratio, the mixing ratio of the chloroacetic acid and the water is 1:(8-12).

[0086] By limiting the mixing ratio of chloroacetic acid and water, it is beneficial to ensure the completeness of carboxylation, and further ensure the performance of the porous silica film treated with carboxylation.

[0087] Further, in step B, the mixing ratio of the anhydrous ferric chloride and the water is 1: (2-4) calculated by mass ratio;

[0088] In step B, the heating temperature is 60-80°C.

[0089] If the ferric chloride content in the ferric chloride solution is too low, the amount of water in the ferric chloride solution will be too high, requiring the ferric chloride solution to be heated for a long time before it can be completely precipitated as ferric chloride hexahydrate, which can easily reduce production efficiency. In addition, the mixing ratio of anhydrous ferric chloride and deionized water is related to the amount of silica-ferroferric oxide magnetic particles obtained after laser processing. If the ferric chloride content in the ferric chloride solution is too low, the amount of silica-ferroferric oxide magnetic particles obtained after laser processing will be too small. If the ferric chloride content in the ferric chloride solution is too high, the amount of ferric chloride hexahydrate precipitated from the ferric chloride solution will be too high, resulting in excessive subsequent laser processing time and affecting processing efficiency.

[0090] Furthermore, since ferric chloride is a covalent iron salt compound that is easily soluble in water and has strong water absorption, when the heating temperature is below 60°C, the precipitation rate of the ferric chloride solution into ferric chloride hexahydrate is too slow, affecting processing efficiency; when the heating temperature is above 80°C, the ferric chloride solution easily hydrolyzes to form hydrogen chloride and ferric hydroxide precipitates, affecting the processing environment and subsequent laser processing. Therefore, the preferred heating temperature of the ferric chloride solution in this technical solution is 60-80°C, which is conducive to ensuring processing speed and processing performance.

[0091] Further description, in step C, the laser wavelength of the laser processing is 350-360 nm, and the laser power is 10-15 W.

[0092] This technical solution limits the laser wavelength and power to ensure that the laser energy is sufficient to break the bonds between atoms or molecules in ferric chloride, thereby converting ferric chloride into ferroferric oxide. The converted ferroferric oxide can then bond tightly with silicon dioxide to form a silicon dioxide-ferroferric oxide precursor. Furthermore, the laser processing with a wavelength of 350-360nm and a power of 10-15W has the characteristics of fast processing speed, high processing precision and stable power, which not only helps to improve the consistency of the product, but also helps to avoid significant damage to the porous silicon dioxide film during processing.

[0093] Further, in step D, the ultrasonic oscillation time is 3 to 5 minutes and the frequency is 30 to 40 kHz.

[0094] By controlling the ultrasonic oscillation time and frequency, the silica-ferroferric oxide precursor is broken up by the ultrasonic oscillation, forming silica-ferroferric oxide magnetic particles with a particle size of 100nm to 10μm. The silica-ferroferric oxide magnetic particles with a particle size of 100nm to 10μm have high consistency, strong magnetic field response ability, and are easy to control, making them suitable for the preparation of magnetically driven micro-nano robots with high consistency and strong maneuverability.

[0095] A silicon dioxide-ferroferric oxide magnetic particle is prepared using the above-mentioned method for preparing a silicon dioxide-ferroferric oxide magnetic particle.

[0096] The present technical solution also proposes a method for preparing silicon dioxide-ferroferric oxide magnetic particles. The silicon dioxide-ferroferric oxide magnetic particles prepared have not only high suspension stability but also strong adsorption capacity.

[0097] An application of silica-ferroferric oxide magnetic particles in the preparation of magnetically driven clustered micro-nano robots, using the aforementioned silica-ferroferric oxide magnetic particles, and an application method comprising: dispersing the silica-ferroferric oxide magnetic particles in a polyvinyl pyrrolidone solution, applying a rotating magnetic field, and magnetizing to obtain a magnetically driven clustered micro-nano robot;

[0098] Wherein, calculated by mass percentage, the content of polyvinyl pyrrolidone in the polyvinyl pyrrolidone solution is 2-5%;

[0099] The shape of the magnetically driven cluster micro-nano robot is circular or elliptical, and the drug loading rate is 80-85%.

[0100] This technical solution also proposes the use of silica-FeO4 magnetic particles in the preparation of magnetically driven swarm micro-nanorobotic devices. The magnetically driven swarm micro-nanorobotic devices are obtained by magnetizing the silica-FeO4 magnetic particles under a magnetic field. The drug-loading performance of the magnetically driven swarm micro-nanorobotic devices is directly related to the adsorption capacity of the silica-FeO4 magnetic particles; the stronger the adsorption capacity of the particles, the greater the drug-loading capacity of the magnetically driven swarm micro-nanorobotic devices. Furthermore, the positioning accuracy of the magnetically driven swarm micro-nanorobotic devices is highly dependent on the suspension stability of the particles; the higher the suspension stability, the more accurate the positioning of the magnetically driven swarm micro-nanorobotic devices. Thanks to the high suspension stability and strong adsorption capacity of the silica-FeO4 magnetic particles in this technical solution, the drug-loading efficiency of the magnetically driven swarm micro-nanorobotic devices prepared is 80-85%. This not only demonstrates strong drug-loading capacity but also precise positioning, greatly meeting the needs of practical applications.

[0101] It should be noted that the silica-ferroferric oxide magnetic particles can effectively prevent the agglomeration of particles due to their inherent suspension stability. In addition, the polyvinyl pyrrolidone solution exhibits certain viscosity and fluid resistance properties, which further enhance the effect of preventing the agglomeration of silica-ferroferric oxide magnetic particles. The above combined advantages not only promote the stable dispersion of particles, but also facilitate the precise control of silica-ferroferric oxide magnetic particles through magnetic fields, thereby facilitating the construction of magnetically driven clustered micro-nano robots.

[0102] The technical solution of the present invention is further illustrated below through specific implementation methods.

[0103] Example 1

[0104] A. Prepare a porous silica film; perform amino treatment on the porous silica film to obtain a porous silica film with amino groups on the surface; wherein the amino groups are used to combine with drug molecules and to form charged groups in the solution; the preparation method of the porous silica film is specifically as follows: apply a silica precursor solution on the surface of a glass substrate, and obtain a glass substrate with silica gel attached to the surface after laser processing; place the glass substrate with silica gel attached to the surface into a mixed solution of ethanol and water to obtain a glass substrate with a porous silica film attached to the surface; peel off the porous silica film on the surface of the glass substrate to obtain a porous silica film; the raw materials of the silica precursor solution include hexadecyltrimethylammonium bromide, tetraethyl orthosilicate solution and hydrochloric acid solution, and the mixing ratio of hexadecyltrimethylammonium bromide, tetraethyl orthosilicate solution and hydrochloric acid solution is 0.1:1:0.001 according to the volume ratio; hydrochloric acid The concentration of hydrochloric acid in the solution is 0.01 mol / L; the raw materials of the tetraethyl orthosilicate solution include tetraethyl orthosilicate, anhydrous ethanol and water, and the mixing ratio of tetraethyl orthosilicate, anhydrous ethanol and water is 1:2:8 according to the molar ratio; the specific method of the amination treatment is: laser processing the porous silica film to obtain a porous silica film with increased surface activity; coating the amination precursor solution on the surface of the porous silica film with increased surface activity, and heating it at 50°C for 0.6h to obtain the amination-treated porous silica film; wherein, according to the volume ratio, the mixing ratio of the 3-aminopropyltriethoxysilane solution and the acetic acid solution in the amination precursor solution is 1:0.01; according to the molar ratio, the mixing ratio of 3-aminopropyltriethoxysilane, anhydrous ethanol and water in the 3-aminopropyltriethoxysilane solution is 1:10:12; the concentration of acetic acid in the acetic acid solution is 0.01 mol / L;

[0105] B. dissolving anhydrous ferric chloride in water and stirring uniformly to obtain a ferric chloride solution; immersing the porous silica film with amino groups on its surface prepared in step A in the ferric chloride solution, removing the film and heating it at 80° C. to obtain a porous silica film with ferric chloride hexahydrate attached to its surface; the mixing ratio of anhydrous ferric chloride to water is 1:2, calculated by mass ratio;

[0106] C. The porous silica film with ferric chloride hexahydrate attached to the surface in step B is laser processed using a laser with a wavelength of 350 nm and a power of 12 W to obtain a porous silica film with a silicon dioxide-ferroferric oxide precursor attached to the surface;

[0107] D. peeling off the silica-ferroferric oxide precursor on the surface of the porous silica film in step C to obtain a silica-ferroferric oxide precursor; ultrasonically oscillating the silica-ferroferric oxide precursor in an ultrasonic oscillator with an oscillation frequency of 35 kHz for 4 minutes to obtain silica-ferroferric oxide magnetic particles.

[0108] The silica-ferroic oxide magnetic particles obtained in Example 1 were dispersed in a polyvinyl pyrrolidone solution containing 3 wt% polyvinyl pyrrolidone, and a rotating magnetic field was applied to magnetize the resulting magnetically driven cluster micro-nanorobot. The magnetically driven cluster micro-nanorobot was immersed in a doxorubicin solution with a concentration of 50-60 μg / ml, allowed to stand for 2 hours, and then removed to obtain a magnetically driven cluster micro-nanorobot loaded with doxorubicin. The magnetically driven cluster micro-nanorobot was then driven in a rotating magnetic field with an intensity of 8 mT to target the affected area for recruitment. The concentration of the doxorubicin solution after immersion of the magnetically driven cluster micro-nanorobot was measured using a fluorescence spectrophotometer to calculate the drug loading rate of the magnetically driven cluster micro-nanorobot. The motion trajectory of the magnetically driven cluster micro-nanorobot was observed under a microscope.

[0109] Experimental results show that the drug loading rate of the magnetically driven cluster micro-nano robot prepared in Example 1 is 85%. It can accurately target the lesion area under the guidance of a rotating magnetic field and achieve precise positioning and delivery of doxorubicin. The drug loading performance of the magnetically driven cluster micro-nano robot is directly related to the adsorption force of the silica-iron tetroxide magnetic particles. Specifically, as the adsorption force of the silica-iron tetroxide magnetic particles increases, the drug loading capacity of the magnetically driven cluster micro-nano robot constructed based on the silica-iron tetroxide magnetic particles also increases. In addition, the positioning accuracy of the magnetically driven cluster micro-nano robot is closely related to the suspension stability of the silica-iron tetroxide magnetic particles; the higher the suspension stability of the silica-iron tetroxide magnetic particles, the more accurate the positioning of the prepared magnetically driven cluster micro-nano robot. The performance of the magnetically driven cluster micro-nano robot demonstrated in Example 1 verifies that the silica-iron tetroxide magnetic particles in this technical solution have excellent suspension stability and strong adsorption capacity.

[0110] Example 2

[0111] A. preparing a porous silica film; performing carboxyl treatment on the porous silica film to obtain a porous silica film with carboxyl groups on the surface; wherein the carboxyl groups are used to combine with drug molecules and to form charged groups in the solution; the preparation method of the porous silica film is specifically as follows: coating a silica precursor solution on the surface of a glass substrate, and obtaining a glass substrate with silica gel attached to the surface after laser processing; placing the glass substrate with silica gel attached to the surface into a mixed solution of ethanol and water to obtain a glass substrate with a porous silica film attached to the surface; peeling off the porous silica film on the surface of the glass substrate to obtain a porous silica film; the raw materials of the silica precursor solution include sodium lauryl sulfate, tetraethyl orthosilicate solution and hydrochloric acid solution, and calculated according to the volume ratio, the silica precursor solution comprises sodium lauryl sulfate, tetraethyl orthosilicate solution and hydrochloric acid solution. The mixing ratio of sodium alkyl sulfate, tetraethyl orthosilicate solution and hydrochloric acid solution is 0.3:1:0.005; the concentration of hydrochloric acid in the hydrochloric acid solution is 0.01 to 0.03 mol / L; the raw materials of the tetraethyl orthosilicate solution include tetraethyl orthosilicate, anhydrous ethanol and water, and the mixing ratio of tetraethyl orthosilicate, anhydrous ethanol and water is 1:3:8 according to the molar ratio; the specific method of carboxylation treatment is: laser processing the porous silica film to obtain a porous silica film with increased surface activity; coating the carboxylation precursor solution on the surface of the porous silica film with increased surface activity, and heating it at 60°C for 0.5°C to obtain a carboxylated porous silica film; wherein, the mixing ratio of chloroacetic acid and water in the carboxylation precursor solution is 1:8 according to the volume ratio;

[0112] B. dissolving anhydrous ferric chloride in water and stirring uniformly to obtain a ferric chloride solution; immersing the porous silica film with carboxyl groups on the surface prepared in step A in the ferric chloride solution, removing the film and heating it at 60° C. to obtain a porous silica film with ferric chloride hexahydrate attached to the surface; the mixing ratio of anhydrous ferric chloride to water is 1:4, calculated by mass ratio;

[0113] C. The porous silica film with ferric chloride hexahydrate attached to the surface in step B is laser processed using a laser with a wavelength of 360 nm and a power of 15 W to obtain a porous silica film with a silicon dioxide-ferroferric oxide precursor attached to the surface;

[0114] D. peeling off the silica-Fe 3 O 4 precursor on the surface of the porous silica film in step C to obtain a silica-Fe 3 O 4 precursor; ultrasonically oscillating the silica-Fe 3 O 4 precursor in an ultrasonic oscillator at an oscillation frequency of 30 kHz for 5 minutes to obtain silica-Fe 3 O 4 magnetic particles.

[0115] The silica-ferroic oxide magnetic particles obtained in Example 2 were dispersed in a polyvinyl pyrrolidone solution containing 3 wt% polyvinyl pyrrolidone, and a rotating magnetic field was applied to magnetize the magnetically driven cluster micro-nanorobot. The magnetically driven cluster micro-nanorobot was immersed in a doxorubicin solution with a concentration of 50-60 μg / ml, allowed to stand for 2 hours, and then removed to obtain a magnetically driven cluster micro-nanorobot loaded with doxorubicin. The magnetically driven cluster micro-nanorobot was driven in a rotating magnetic field with an intensity of 8 mT to target the affected area for recruitment. The concentration of the doxorubicin solution after immersion of the magnetically driven cluster micro-nanorobot was measured using a fluorescence spectrophotometer to calculate the drug loading rate of the magnetically driven cluster micro-nanorobot, and the motion trajectory of the magnetically driven cluster micro-nanorobot was observed under a microscope.

[0116] The experimental results show that the drug loading rate of the magnetically driven cluster micro-nano robot prepared in Example 2 is 83%. It can accurately target the lesion area under the guidance of a rotating magnetic field and achieve precise positioning and delivery of doxorubicin. The drug loading performance of the magnetically driven cluster micro-nano robot is directly related to the adsorption force of the silica-iron tetroxide magnetic particles. Specifically, as the adsorption force of the silica-iron tetroxide magnetic particles increases, the drug loading capacity of the magnetically driven cluster micro-nano robot constructed based on the silica-iron tetroxide magnetic particles also increases. In addition, the positioning accuracy of the magnetically driven cluster micro-nano robot is closely related to the suspension stability of the silica-iron tetroxide magnetic particles; the higher the suspension stability of the silica-iron tetroxide magnetic particles, the more accurate the positioning of the prepared magnetically driven cluster micro-nano robot. The performance of the magnetically driven cluster micro-nano robot demonstrated in Example 2 verifies that the silica-iron tetroxide magnetic particles in this technical solution have excellent suspension stability and strong adsorption capacity.

[0117] Example 3

[0118] A. Prepare a porous silica film; perform amino treatment on the porous silica film to obtain a porous silica film with amino groups on the surface; wherein the amino groups are used to combine with drug molecules and to form charged groups in the solution; the preparation method of the porous silica film is specifically as follows: apply a silica precursor solution on the surface of a glass substrate, and obtain a glass substrate with silica gel attached to the surface after laser processing; place the glass substrate with silica gel attached to the surface into a mixed solution of ethanol and water to obtain a glass substrate with a porous silica film attached to the surface; peel off the porous silica film on the surface of the glass substrate to obtain a porous silica film; the raw materials of the silica precursor solution include hexadecyltrimethylammonium bromide, tetraethyl orthosilicate solution and hydrochloric acid solution, and the mixing ratio of hexadecyltrimethylammonium bromide, tetraethyl orthosilicate solution and hydrochloric acid solution is 0.2:1:0.003 according to the volume ratio; hydrochloric acid The concentration of hydrochloric acid in the solution is 0.03 mol / L; the raw materials of the tetraethyl orthosilicate solution include tetraethyl orthosilicate, anhydrous ethanol and water, and the mixing ratio of tetraethyl orthosilicate, anhydrous ethanol and water is 1:4:9 according to the molar ratio; the specific method of the amination treatment is: laser processing the porous silica film to obtain a porous silica film with increased surface activity; coating the amination precursor solution on the surface of the porous silica film with increased surface activity, and heating it at 58°C for 0.55h to obtain the amination-treated porous silica film; wherein, according to the volume ratio, the mixing ratio of the 3-aminopropyltriethoxysilane solution and the acetic acid solution in the amination precursor solution is 1:0.05; according to the molar ratio, the mixing ratio of 3-aminopropyltriethoxysilane, anhydrous ethanol and water in the 3-aminopropyltriethoxysilane solution is 1:11:10; the concentration of acetic acid in the acetic acid solution is 0.02 mol / L;

[0119] B. dissolving anhydrous ferric chloride in water and stirring uniformly to obtain a ferric chloride solution; immersing the porous silica film with carboxyl groups on the surface prepared in step A in the ferric chloride solution, removing the film and heating it at 70° C. to obtain a porous silica film with ferric chloride hexahydrate attached to the surface; the mixing ratio of anhydrous ferric chloride to water is 1:4, calculated by mass ratio;

[0120] C. The porous silica film with ferric chloride hexahydrate attached to the surface in step B is laser processed using a laser with a wavelength of 350 nm and a power of 10 W to obtain a porous silica film with a silicon dioxide-ferroferric oxide precursor attached to the surface;

[0121] D. peeling off the silica-Fe 3 O 4 precursor on the surface of the porous silica film in step C to obtain a silica-Fe 3 O 4 precursor; ultrasonically oscillating the silica-Fe 3 O 4 precursor in an ultrasonic oscillator at an oscillation frequency of 40 kHz for 3 minutes to obtain silica-Fe 3 O 4 magnetic particles.

[0122] The silica-ferroic oxide magnetic particles obtained in Example 3 were dispersed in a polyvinyl pyrrolidone solution containing 3 wt% polyvinyl pyrrolidone, and a rotating magnetic field was applied to magnetize the resulting magnetically driven cluster micro-nanorobot. The magnetically driven cluster micro-nanorobot was immersed in a doxorubicin solution with a concentration of 50-60 μg / ml, allowed to stand for 2 hours, and then removed to obtain a magnetically driven cluster micro-nanorobot loaded with doxorubicin. The magnetically driven cluster micro-nanorobot was then driven in a rotating magnetic field with an intensity of 8 mT to target the affected area for recruitment. The concentration of the doxorubicin solution after immersion of the magnetically driven cluster micro-nanorobot was measured using a fluorescence spectrophotometer to calculate the drug loading rate of the magnetically driven cluster micro-nanorobot, and the motion trajectory of the magnetically driven cluster micro-nanorobot was observed under a microscope.

[0123] The experimental results show that the drug loading rate of the magnetically driven cluster micro-nano robot prepared in Example 3 is 81%. It can accurately target the lesion area under the guidance of a rotating magnetic field and achieve precise positioning and delivery of doxorubicin. The drug loading performance of the magnetically driven cluster micro-nano robot is directly related to the adsorption force of the silica-iron tetroxide magnetic particles. Specifically, as the adsorption force of the silica-iron tetroxide magnetic particles increases, the drug loading capacity of the magnetically driven cluster micro-nano robot constructed based on the silica-iron tetroxide magnetic particles also increases. In addition, the positioning accuracy of the magnetically driven cluster micro-nano robot is closely related to the suspension stability of the silica-iron tetroxide magnetic particles; the higher the suspension stability of the silica-iron tetroxide magnetic particles, the more accurate the positioning of the prepared magnetically driven cluster micro-nano robot. The performance of the magnetically driven cluster micro-nano robot demonstrated in Example 3 verifies that the silica-iron tetroxide magnetic particles in this technical solution have excellent suspension stability and strong adsorption capacity.

[0124] Comparative Example 1

[0125] The preparation method and raw materials used in Comparative Example 1 are the same as those in the examples, except that a silicon dioxide film is used instead of a porous silicon dioxide film in Comparative Example 1. That is, the preparation method of the silica film in Comparative Example 1 is specifically as follows: a silica precursor solution is coated on the surface of a substrate, and a substrate with silica gel attached to the surface is obtained after laser processing; the substrate with silica gel attached to the surface is placed in a mixed solution of ethanol and water to obtain a substrate with a silica film attached to the surface; the silica film on the surface of the substrate is peeled off to obtain a silica film; wherein, the raw materials of the silica precursor solution include tetraethyl orthosilicate solution and hydrochloric acid solution, and calculated according to the volume ratio, the mixing ratio of tetraethyl orthosilicate solution and hydrochloric acid solution is (0.1~0.3):1:(0.001~0.005); the raw materials of the tetraethyl orthosilicate solution include tetraethyl orthosilicate, anhydrous ethanol and water, and calculated according to the molar ratio, the mixing ratio of tetraethyl orthosilicate, anhydrous ethanol and the water is 1:(2~6):(8~12).

[0126] The silica-ferroic oxide magnetic particles obtained in Comparative Example 1 were dispersed in a polyvinyl pyrrolidone solution containing 3 wt% polyvinyl pyrrolidone, and a rotating magnetic field was applied to magnetize the magnetically driven cluster micro-nano robot. The magnetically driven cluster micro-nano robot was immersed in a doxorubicin solution with a concentration of 50 to 60 μg / ml, and then taken out after standing for 2 hours to obtain a magnetically driven cluster micro-nano robot loaded with doxorubicin; the magnetically driven cluster micro-nano robot was driven in a rotating magnetic field with an intensity of 8 mT to target the affected area for recruitment. The concentration of the doxorubicin solution after immersion of the magnetically driven cluster micro-nano robot was measured using a fluorescence spectrophotometer to calculate the drug loading rate of the magnetically driven cluster micro-nano robot, and the motion trajectory of the magnetically driven cluster micro-nano robot was observed under a microscope.

[0127] Experimental results show that the drug loading rate of the magnetically driven cluster micro-nano robot prepared in Comparative Example 1 is only 43%, which cannot meet the drug loading requirements. Furthermore, the robot cannot accurately target the lesion area under the guidance of a rotating magnetic field, and cannot achieve precise positioning and delivery of doxorubicin. This is because the silica film in Comparative Example 1 does not have a porous structure, which affects its suspension stability and adsorption capacity. This results in a decrease in the positioning accuracy and drug loading capacity of the magnetically driven cluster micro-nano robot obtained by magnetizing silica-ferroferric oxide magnetic particles under the action of a magnetic field.

[0128] Comparative Example 2

[0129] The preparation method and raw materials used in Comparative Example 2 are the same as those in Example 1, except that the porous silica film is not subjected to an amination treatment in Comparative Example 2.

[0130] The silica-ferroic oxide magnetic particles obtained in Comparative Example 2 were dispersed in a polyvinyl pyrrolidone solution containing 3 wt% polyvinyl pyrrolidone, and a rotating magnetic field was applied to magnetize the magnetically driven cluster micro-nano robot. The magnetically driven cluster micro-nano robot was immersed in a doxorubicin solution with a concentration of 50 to 60 μg / ml, and then taken out after standing for 2 hours to obtain a magnetically driven cluster micro-nano robot loaded with doxorubicin; the magnetically driven cluster micro-nano robot was driven in a rotating magnetic field with an intensity of 8 mT to target the affected area for recruitment. The concentration of the doxorubicin solution after the magnetically driven cluster micro-nano robot was measured using a fluorescence spectrophotometer to calculate the drug loading rate of the magnetically driven cluster micro-nano robot, and the motion trajectory of the magnetically driven cluster micro-nano robot was observed under a microscope.

[0131] The experimental results show that the drug loading rate of the magnetically driven cluster micro-nano robot prepared in Comparative Example 2 is only 65%, which cannot meet the drug loading requirements, and cannot accurately target the lesion area under the guidance of the rotating magnetic field, and cannot achieve precise positioning and delivery of doxorubicin. This is because the porous silica film in Comparative Example 2 was not aminated, which affects its suspension stability and adsorption capacity, resulting in a decrease in the positioning accuracy and drug loading capacity of the magnetically driven cluster micro-nano robot obtained by magnetizing silica-ferroferric oxide magnetic particles under the action of a magnetic field.

[0132] The technical principles of the present invention have been described above with reference to specific embodiments. These descriptions are intended solely to illustrate the principles of the present invention and are not to be construed in any way as limiting the scope of protection of the present invention. Based on the explanations herein, those skilled in the art will readily conceive of other specific embodiments of the present invention without inventive effort, and such embodiments will fall within the scope of protection of the present invention.

Claims

1. A method for preparing silicon dioxide-ferroferric oxide magnetic particles, characterized in that: The following steps are involved: A. preparing a porous silica film; performing a functional treatment on the porous silica film to obtain a porous silica film having functional groups on its surface; wherein the functional groups are used to bind to drug molecules and to form charged groups in the solution; The preparation method of the porous silicon dioxide film is specifically as follows: A silica precursor solution is coated on the surface of a substrate, and a substrate with silica gel attached to the surface is obtained after laser processing; placing the substrate with the silica gel attached to the surface into a mixed solution of ethanol and water to obtain a substrate with a porous silica film attached to the surface; peeling off the porous silica film on the surface of the substrate to obtain a porous silica film; The raw materials of the silicon dioxide precursor solution include a template, a tetraethyl orthosilicate solution and a hydrochloric acid solution; The raw materials of the tetraethyl orthosilicate solution include tetraethyl orthosilicate, anhydrous ethanol and water; B. dissolving anhydrous ferric chloride in water and stirring to obtain a ferric chloride solution; immersing the porous silica film with functional groups on the surface in step A in the ferric chloride solution, removing the film and heating it to obtain a porous silica film with ferric chloride hexahydrate attached to the surface; C. laser processing the porous silica film with ferric chloride hexahydrate attached to the surface in step B to obtain a porous silica film with a silica-ferroferric oxide precursor attached to the surface; D. peeling off the silica-ferroferric oxide precursor on the surface of the porous silica film in step C to obtain a silica-ferroferric oxide precursor; and ultrasonically vibrating the silica-ferroferric oxide precursor to obtain silica-ferroferric oxide magnetic particles.

2. The method for preparing silicon dioxide-ferroferric oxide magnetic particles according to claim 1, wherein: In step A, the mixing ratio of the template, the tetraethyl orthosilicate solution, and the hydrochloric acid solution is (0.1-0.3):1:(0.001-0.005) calculated by volume; Calculated by molar ratio, the mixing ratio of the tetraethyl orthosilicate, the anhydrous ethanol and the water is 1: (2-6): (8-12).

3. The method for preparing silicon dioxide-ferroferric oxide magnetic particles according to claim 1, wherein: In step A, the functionalization treatment is an amination treatment or a carboxylation treatment; The functional group includes any one of an amino group and a carboxyl group.

4. The method for preparing silicon dioxide-ferroferric oxide magnetic particles according to claim 3, wherein: The specific method of the amination treatment is: performing laser processing on the porous silica film to obtain a porous silica film with increased surface activity; applying an amination precursor solution on the surface of the porous silica film with increased surface activity, and heating at 50 to 60° C. for 0.5 to 0.6 hours to obtain the amination-treated porous silica film; The raw materials of the amination precursor solution include 3-aminopropyltriethoxysilane solution and acetic acid solution; the raw materials of the 3-aminopropyltriethoxysilane solution include 3-aminopropyltriethoxysilane, anhydrous ethanol and water.

5. The method for preparing silicon dioxide-ferroferric oxide magnetic particles according to claim 3, characterized in that: The specific method of the carboxylation treatment is as follows: performing laser processing on the porous silica film to obtain a porous silica film with increased surface activity; coating the surface of the porous silica film with increased surface activity with a carboxylation precursor solution, and heating the porous silica film at 50 to 60° C. for 0.5 to 0.6° C. to obtain a carboxylation-treated porous silica film; Wherein, the raw materials of the carboxylation precursor solution include chloroacetic acid and water.

6. The method for preparing silicon dioxide-ferroferric oxide magnetic particles according to claim 1, wherein: In step B, the mixing ratio of the anhydrous ferric chloride and the water is 1:(2-4) calculated by mass ratio; In step B, the heating temperature is 60-80°C.

7. The method for preparing silicon dioxide-ferroferric oxide magnetic particles according to claim 1, wherein: In step C, the laser wavelength of the laser processing is 350-360 nm, and the laser power is 10-15 W.

8. The method for preparing silicon dioxide-ferroferric oxide magnetic particles according to claim 1, wherein: In step D, the ultrasonic oscillation time is 3 to 5 minutes and the frequency is 30 to 40 kHz.

9. A silicon dioxide-ferroferric oxide magnetic particle, characterized in that: The silicon dioxide-ferroferric oxide magnetic particles are prepared using the preparation method of any one of claims 1 to 8.

10. An application of silicon dioxide-ferroferric oxide magnetic particles in the preparation of magnetically driven cluster micro-nano robots, characterized in that: The silicon dioxide-ferroferric oxide magnetic particles according to claim 9 are used in the following application method: the silicon dioxide-ferroferric oxide magnetic particles are dispersed in a polyvinyl pyrrolidone solution, and a rotating magnetic field is applied to magnetize the particles to obtain a magnetically driven clustered micro-nano robot; Wherein, calculated by mass percentage, the content of polyvinyl pyrrolidone in the polyvinyl pyrrolidone solution is 2-5%; The shape of the magnetically driven cluster micro-nano robot is circular or elliptical, and the drug loading rate is 80-85%.