Method for improving ion tolerance of self-electrophoresis driven micro-nano motor and application thereof

Abstract

The invention discloses a method for improving ion tolerance of a self-electrophoresis-driven micro-nano motor and application of the method, and belongs to the technical field of micro-nano motors. The surface of the self-electrophoresis-driven micro-nano motor is modified with a metal organic framework (MOF) pore structure material, so that the ion tolerance of the self-electrophoresis-driven micro-nano motor in a high-salt environment is remarkably improved; compared with a self-electrophoresis-driven micro-nano motor without surface modification of the MOF pore structure material, the ion tolerance of the self-electrophoresis-driven micro-nano motor with the surface modification of the MOF pore structure material can be improved by 266 times, so that the self-electrophoresis-driven micro-nano motor can keep stable movement under the electrolyte concentration up to 150mM; the problem of ion quenching of the micro-nano motor driven by an electrophoresis mechanism in a high-salt solution is solved, and the driving efficiency is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of micro-nano motors, and particularly relates to a method for improving the ion tolerance of self-electrophoretic driven micro-nano motors and its application. Background Art

[0002] Micro-nano motors can convert various types of energy (such as chemical energy, magnetic energy, acoustic energy, and light energy) into mechanical motion, so as to perform complex tasks at the micro-nano scale. With its precise controllability, high propulsion force, and easy functionalization, micro-nano motors have become promising candidates in biomedical applications, especially in the fields of drug delivery and precision medicine.

[0003] Among various types of micro-nano motors, self-electrophoretic driven micro-nano motors have attracted great interest. These self-electrophoretic driven micro-nano motors generate propulsion force through surface asymmetric chemical reactions, which can be easily adjusted and provide great flexibility for design. Such self-electrophoretic driven micro-nano motors are expected to become ideal artificial systems for simulating biological chemotaxis, that is, cell migration guided by chemical gradients. They provide a promising platform for targeted drug delivery and precision medicine.

[0004] However, self-electrophoretic driven micro-nano motors face the problem of ion quenching in high-salt environments (such as blood and biological fluids). The classical Helmholtz-Smoluchowski theory shows that high ionic strength will cause the Debye layer to collapse and completely inhibit the propulsion driven by self-electrophoresis. The salt concentration in biological media usually exceeds 150 mM. For example, the osmotic pressure of blood is mainly maintained by Na + , Cl - and HCO3 - and other ions, and the concentration is usually between 290 and 310 mM. Therefore, for biomedical applications, it is crucial to overcome the problem of high salt concentration (exceeding 150 mM) in biological media. Summary of the Invention

[0005] To solve the above technical problems, the present invention proposes a method for improving the ion tolerance of self-electrophoretic driven micro-nano motors and its application.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A method for improving the ion tolerance of self-electrophoretic driven micro-nano motors, after subjecting the self-electrophoretic driven micro-nano motors to oxygen plasma treatment, a metal-organic framework (MOF) pore structure material is modified on the surface of the self-electrophoretic driven micro-nano motors.

[0008] In a high-salt environment, traditional micro-nano motors often suffer from the collapse of the surface double electric layer (Debye layer) due to the ion shielding effect, severely weakening their self-electrophoretic driving performance. To address this issue, the present invention innovatively modifies the surface of micro-nano motors with metal-organic framework (MOF) pore structure materials, significantly enhancing the ion tolerance of the system through their unique pore structures. Specifically, the highly ordered nano-scale pores inside the MOF pore structure materials form a three-dimensional ion transport network, promoting the migration of electrolyte ions along the pores. By modifying the MOF porous materials on the micro-nano motors, the present invention facilitates the flow of ions around the particles and within the pores. The MOF pore structure materials serve as ion-conducting channels, effectively maintaining the "Debye layer" of micro-nano motors in an electric field under high-salt conditions, thereby maintaining the stability of the self-electrophoretic driving mechanism of micro-nano motors. The highly ordered pore structure of the MOF porous materials can act as an ion transport layer, effectively supporting fluid pumping in a high-salt environment, indicating that the metal-organic framework materials provide ion-conducting channels, effectively enhancing the propulsion force of micro-nano motors, which is the key factor for improving ion tolerance.

[0009] The MOF pore structure material includes one of ZIF-8, UiO-66, and MIL-53(Al).

[0010] Furthermore, when the MOF pore structure material is ZIF-8, the method for improving the ion tolerance of self-electrophoretic driving micro-nano motors includes the following steps:

[0011] Perform oxygen plasma treatment on the self-electrophoretic driving micro-nano motors to obtain pre-treated self-electrophoretic driving micro-nano motors. After pretreatment, the surface of the self-electrophoretic driving micro-nano motors is hydroxylated.

[0012] First, add the pre-treated self-electrophoretic driving micro-nano motors to an aqueous solution of dimethylimidazole, and then add an aqueous solution of soluble zinc salt. React for 30 - 60 min (such as 30 min, 40 min, 50 min, or 60 min). After the reaction, naturally cool to room temperature, and wash and dry the self-electrophoretic driving micro-nano motors.

[0013] The molar ratio of the dimethylimidazole to the soluble zinc salt is 500∶8.

[0014] The preparation method of the aqueous solution of dimethylimidazole is: dissolve dimethylimidazole in water to obtain the aqueous solution of dimethylimidazole; the preparation method of the aqueous solution of soluble zinc salt is: dissolve soluble zinc salt in water to obtain the aqueous solution of soluble zinc salt.

[0015] Exemplarily, the soluble zinc salt is zinc acetate dihydrate.

[0016] Further, when the MOF pore structure material is ZIF-8, the method for improving the ion tolerance of the self-electrophoretic driving micro-nano motor includes the following steps:

[0017] Perform oxygen plasma treatment on the self-electrophoretic driving micro-nano motor to obtain a pre-treated self-electrophoretic driving micro-nano motor;

[0018] Dissolve 4.105 g (0.05 mol) of dimethylimidazole in 50 mL of deionized water to obtain an aqueous solution of dimethylimidazole; dissolve 0.183 g (0.0008 mol) of zinc acetate dihydrate in 10 mL of deionized water to obtain a soluble zinc salt aqueous solution; immerse the pre-treated self-electrophoretic driving micro-nano motor in the aqueous solution of dimethylimidazole for 3 minutes, and then add the soluble zinc salt aqueous solution. React at room temperature and normal pressure for 40 min. After the reaction, cool naturally to room temperature, and thoroughly wash the self-electrophoretic driving micro-nano motor with deionized water and methanol. After drying, a silicon nanowire micro-nano motor with a ZIF-8 pore structure material modified on its surface is obtained, which is an ion-tolerant self-electrophoretic driving micro-nano motor and can be used in an environment with an ion concentration of up to 150 mM.

[0019] Further, when the MOF pore structure material is UiO-66, the method for improving the ion tolerance of the self-electrophoretic driving micro-nano motor includes the following steps:

[0020] Perform oxygen plasma treatment on the self-electrophoretic driving micro-nano motor to obtain a pre-treated self-electrophoretic driving micro-nano motor;

[0021] After stirring 0.25 mmol of zirconium tetrachloride, 0.25 mmol of terephthalic acid and 30 mL of N,N-dimethylformamide evenly, pour them into a reaction kettle. Place the pre-treated self-electrophoretic driving micro-nano motor in the solution and heat at 145 °C for 48 hours. After the reaction, cool naturally to room temperature, and wash and dry the self-electrophoretic driving micro-nano motor.

[0022] When the MOF pore structure material is UiO-66, in the method for improving the ion tolerance of the self-electrophoretic driving micro-nano motor, the steps of washing and drying the self-electrophoretic driving micro-nano motor are: wash the self-electrophoretic driving micro-nano motor 3 times with DMF (N,N-dimethylformamide) and ethanol to remove unreacted precursors, and then dry it under vacuum at 60 °C for 12 hours.

[0023] Further, when the MOF pore structure material is MIL-53(Al), the method for improving the ion tolerance of the self-electrophoretic driving micro-nano motor includes the following steps:

[0024] Perform oxygen plasma treatment on the self-electrophoretic driving micro-nano motor to obtain a pre-treated self-electrophoretic driving micro-nano motor;

[0025] Aluminum nitrate nonahydrate and terephthalic acid were dissolved in deionized water at a molar ratio of 1:1. After stirring until dissolved, the resulting solution was transferred to a high-pressure reactor. The pretreated self-electrophoretic driving micro-nano motor was placed in the solution and reacted at 150 °C for 24 hours. Then it was washed with deionized water and methanol and dried under vacuum at 80 °C.

[0026] The self-electrophoretic driving micro-nano motor includes a silicon-based self-electrophoretic driving micro-nano motor or a titanium-based self-electrophoretic driving micro-nano motor.

[0027] Exemplarily, the silicon-based self-electrophoretic driving micro-nano motor includes a silicon nanowire micro-nano motor or a SiO2-Pt micro-nano motor;

[0028] And / or, the titanium-based self-electrophoretic driving micro-nano motor is selected from a TiO2-Pt micro-nano motor.

[0029] The present invention also provides a self-electrophoretic driving micro-nano motor with high ion tolerance obtained by the above method. The salt tolerance concentration of the self-electrophoretic driving micro-nano motor with high ion tolerance is 150 mM, that is, the self-electrophoretic driving micro-nano motor treated by the method of the present invention can be applied at a salt concentration of 150 mM.

[0030] The present invention also provides the application of the self-electrophoretic driving micro-nano motor with high ion tolerance in micro-region object transport materials, targeted drug delivery materials or photo-neuroregulation materials.

[0031] The self-electrophoretic driving micro-nano motor with high ion tolerance of the present invention is a near-infrared driving micro-nano motor. The near-infrared driving micro-nano motor means that the micro-nano motor can be driven by near-infrared light and the movement direction can be guided under an external magnetic field. The intensity of the near-infrared light is 10 - 1200 mW / cm 2 ; The external magnetic field is a gradient magnetic field with an adjustable direction.

[0032] Compared with the prior art, the present invention has the following advantages and technical effects:

[0033] 1. By modifying the surface of the self-electrophoretic driving micro-nano motor with porous structure materials (such as ZIF-8, UiO-66 or MIL-53), the present invention utilizes its porosity to provide an ion conduction channel, enabling the self-electrophoretic driving micro-nano motor to maintain good propulsion performance in high-salt solutions;

[0034] 2. The self-electrophoretic driving micro-nano motor with a MOF pore structure material modified on its surface of the present invention can be propelled by 980 nm near-infrared light. Even through an artificial blood vessel covered with biological tissue, it can still move stably and controllably, which provides a reliable power source for targeted drug delivery;

[0035] 3. The surface-modified MOF pore structure material of the present invention is universal and scalable. For example, it can be extended to other types of self-electrophoresis-driven micro-nano motors, significantly enhancing their ion tolerance and unlocking new possibilities for biomedical applications;

[0036] 4. The surface-modified MOF pore structure material not only enhances the ion tolerance of the self-electrophoresis-driven micro-nano motor but also endows it with drug loading and pH-responsive release functions, has good biocompatibility, and is suitable for drug delivery systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0038] Figure 1 It is a synthesis route diagram of a silicon nanowire micro-nano motor (MIS-Au@ZIF-8) based on a ZIF-8 pore structure material in Example 1 of the present invention;

[0039] Figure 2 It is an SEM image of a silicon nanowire micro-nano motor based on a ZIF-8 pore structure material in Example 1;

[0040] Figure 3 It is an EDX element distribution diagram of a silicon nanowire micro-nano motor based on a ZIF-8 pore structure material in Example 1;

[0041] Figure 4 It is a salt tolerance curve graph of a silicon nanowire micro-nano motor based on a ZIF-8 pore structure material in Example 1 of the present invention and a silicon nanowire micro-nano motor in Comparative Example 1;

[0042] Figure 5 It is a schematic diagram of the movement process of a silicon nanowire micro-nano motor based on a ZIF-8 pore structure material in Example 1 in an artificial blood vessel under 980 nm near-infrared light driving;

[0043] Figure 6 It is an SEM image of a Janus-structured TiO2-Pt@ZIF-8 micro-nano motor in Example 2 and a Janus-structured SiO2-Pt@ZIF-8 micro-nano motor in Example 3, where a is the TiO2-Pt@ZIF-8 micro-nano motor and b is the SiO2-Pt@ZIF-8 micro-nano motor;

[0044] Figure 7In Figure a, it shows the salt tolerance curves of SiO2-Pt micro-nano motors (SiO2-Pt@ZIF-8) modified with ZIF-8 porous structure materials in Example 3 and SiO2-Pt micro-nano motors (SiO2-Pt) without ZIF-8 porous structure materials in Comparative Example 3 in ferrocene methanol solution at different salt concentrations. In Figure b, it shows the salt tolerance curves of TiO2-Pt micro-nano motors (TiO2-Pt@ZIF-8) modified with ZIF-8 porous structure materials in Example 2 and TiO2-Pt micro-nano motors (TiO2-Pt) without ZIF-8 porous structure materials in Comparative Example 2 in ferrocene methanol solution at different salt concentrations;

[0045] Figure 8 Figure shows the pH-responsive drug release diagram of the micro-nano motor loaded with drugs (DOX) based on silicon nanowires with ZIF-8 porous structure materials in Example 1;

[0046] Figure 9 Figure shows the morphological diagrams of different types of MOF porous structure materials grown on silicon nanowire micro-nano motors in Example 4 and Example 5, where a is Example 4 and b is Example 5. Detailed implementation manners

[0047] Now, various exemplary implementation manners of the present invention will be described in detail. This detailed description should not be considered as a limitation of the present invention, but should be understood as a more detailed description of certain aspects, characteristics, and implementation schemes of the present invention.

[0048] It should be understood that the terms described in the present invention are only for describing specific implementation manners and are not used to limit the present invention. Additionally, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded from the range.

[0049] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0050] Without departing from the scope or spirit of the present invention, various modifications and variations can be made to the specific embodiments of the description of the present invention, which will be obvious to those skilled in the art. Other embodiments obtained from the description of the present invention will be obvious to those skilled in the art. The description and examples of the present invention are merely exemplary.

[0051] Regarding the terms "comprising", "including", "having", "containing", etc. used herein, they are all open-ended terms, meaning including but not limited to.

[0052] The present invention provides a method for improving the ion tolerance of self-electrophoretic driven micro-nano motors. After the self-electrophoretic driven micro-nano motors are treated with oxygen plasma, a metal-organic framework (MOF) pore structure material is modified on the surface of the self-electrophoretic driven micro-nano motors. Exemplarily, the MOF pore structure material includes one of ZIF-8, UiO-66, and MIL-53(Al).

[0053] In some embodiments of the present invention, when the MOF pore structure material is ZIF-8, the method for improving the ion tolerance of self-electrophoretic driven micro-nano motors includes the following steps:

[0054] Treat the self-electrophoretic driven micro-nano motors with oxygen plasma to obtain pretreated self-electrophoretic driven micro-nano motors;

[0055] First, add the pretreated self-electrophoretic driven micro-nano motors to an aqueous solution of 2-methylimidazole, then add an aqueous solution of soluble zinc salt, and react for 30 - 60 min (such as 30 min, 40 min, 50 min, or 60 min). After the reaction, naturally cool to room temperature, and wash and dry the self-electrophoretic driven micro-nano motors. The molar ratio of 2-methylimidazole to soluble zinc salt is 500∶8. The preparation method of the aqueous solution of 2-methylimidazole is: dissolve 2-methylimidazole in water to obtain an aqueous solution of 2-methylimidazole. The preparation method of the aqueous solution of soluble zinc salt is: dissolve soluble zinc salt in water to obtain an aqueous solution of soluble zinc salt. The soluble zinc salt is preferably zinc acetate dihydrate.

[0056] In some preferred embodiments of the present invention, when the MOF pore structure material is ZIF-8, the method for improving the ion tolerance of self-electrophoretic driven micro-nano motors includes the following steps:

[0057] Treat the self-electrophoretic driven micro-nano motors with oxygen plasma to obtain pretreated self-electrophoretic driven micro-nano motors;

[0058] Dissolve 4.105 g (0.05 mol) of dimethylimidazole in 50 mL of deionized water to obtain an aqueous dimethylimidazole solution; dissolve 0.183 g (0.0008 mol) of zinc acetate dihydrate in 10 mL of deionized water to obtain a soluble zinc salt aqueous solution; immerse the pre-treated self-electrophoretic driven micro-nano motor in the aqueous dimethylimidazole solution for 3 minutes, then add the soluble zinc salt aqueous solution, and react at room temperature and atmospheric pressure for 40 min. After the reaction is completed, naturally cool to room temperature, and thoroughly wash the self-electrophoretic driven micro-nano motor with deionized water and methanol. After drying, a silicon nanowire micro-nano motor with a ZIF-8 pore structure material modified on its surface is obtained, which is an ion-tolerant self-electrophoretic driven micro-nano motor and can be used in an environment with an ion concentration of up to 150 mM.

[0059] In some preferred embodiments of the present invention, when the MOF pore structure material is UiO-66, the method for improving the ion tolerance of the self-electrophoretic driven micro-nano motor includes the following steps:

[0060] Perform oxygen plasma treatment on the self-electrophoretic driven micro-nano motor to obtain a pre-treated self-electrophoretic driven micro-nano motor;

[0061] After stirring 0.25 mmol of zirconium tetrachloride, 0.25 mmol of terephthalic acid and 30 mL of N,N-dimethylformamide evenly, pour them into a reaction kettle. Place the pre-treated self-electrophoretic driven micro-nano motor in the solution and heat at 145 °C for 48 hours. After the reaction is completed, naturally cool to room temperature, and wash the self-electrophoretic driven micro-nano motor 3 times with DMF (N,N-dimethylformamide) and ethanol to remove unreacted precursors, and then vacuum dry at 60 °C for 12 hours.

[0062] In some preferred embodiments of the present invention, when the MOF pore structure material is MIL-53(Al), the method for improving the ion tolerance of the self-electrophoretic driven micro-nano motor includes the following steps:

[0063] Perform oxygen plasma treatment on the self-electrophoretic driven micro-nano motor to obtain a pre-treated self-electrophoretic driven micro-nano motor;

[0064] Dissolve aluminum nitrate nonahydrate and terephthalic acid in deionized water according to a molar ratio of 1:1, stir until dissolved, then transfer the obtained solution to a high-pressure reaction kettle. Place the pre-treated self-electrophoretic driven micro-nano motor in the solution and react at 150 °C for 24 hours. Then wash with deionized water and methanol and perform vacuum drying at 80 °C.

[0065] In an embodiment of the present invention, the self-electrophoretic driven micro-nano motor includes a silicon-based self-electrophoretic driven micro-nano motor or a titanium-based self-electrophoretic driven micro-nano motor. Exemplarily, the silicon-based self-electrophoretic driven micro-nano motor includes a silicon nanowire micro-nano motor or a SiO2-Pt micro-nano motor; and / or, the titanium-based self-electrophoretic driven micro-nano motor is selected from a TiO2-Pt micro-nano motor.

[0066] An embodiment of the present invention also provides a self-electrophoretic driven micro-nano motor with high ion tolerance obtained by the above method. The salt tolerance concentration of the self-electrophoretic driven micro-nano motor with high ion tolerance reaches 150 mM, that is, the self-electrophoretic driven micro-nano motor processed by the method of the present invention can be applied at a salt concentration of 150 mM.

[0067] The self-electrophoretic driven micro-nano motor with high ion tolerance provided by the embodiment of the present invention can be used in micro-region object transport materials, targeted drug delivery materials or optoneuroregulation materials. For example, the self-electrophoretic driven micro-nano motor with high ion tolerance of the present invention can be used for drug delivery, neuroregulation, dynamic detection and / or cancer treatment.

[0068] The self-electrophoretic driven micro-nano motor with high ion tolerance of the present invention is a near-infrared driven micro-nano motor. The near-infrared driven micro-nano motor means that the micro-nano motor can be driven by near-infrared light and the movement direction can be guided under an external magnetic field. The intensity of the near-infrared is 10-1200 mW / cm 2 ; the external magnetic field is a gradient magnetic field and the direction is adjustable.

[0069] In the present invention, by modifying the surface of the self-electrophoretic driven micro-nano motor with a metal-organic framework (MOF) pore structure material, the ion tolerance in a high-salt environment is significantly improved. Compared with the self-electrophoretic driven micro-nano motor without surface modification of the MOF pore structure material, the ion tolerance of the self-electrophoretic driven micro-nano motor with surface modification of the MOF pore structure material can be increased by 266 times, enabling the self-electrophoretic driven micro-nano motor to maintain stable movement at an electrolyte concentration as high as 150 mM, solving the problem of ion quenching of the micro-nano motor driven by the electrophoresis mechanism in a high-salt solution and improving the driving efficiency. The micro-nano motor with surface modification of the MOF pore structure material of the present invention exhibits excellent performance in a high-salt environment, and this method is widely applicable to micro-nano motors driven by the electrophoresis mechanism. Utilizing the porous nature of the MOF material, the self-electrophoretic driven micro-nano motor with surface modification of the MOF pore structure material can be used for drug delivery, dynamic monitoring, targeted neuroregulation, precision medicine and other biomedical fields.

[0070] In the present invention, in order to quantify the ion tolerance, the concept of "median effective ion intensity" (EI 50 ) is introduced. EI 50Refers to the salt concentration when the speed of the micro-nano motor drops to half of its initial speed. Compared with the self-electrophoretic driven micro-nano motor made of unmodified MOF pore structure material, the ion tolerance of the self-electrophoretic driven micro-nano motor made of surface-modified MOF pore structure material can be increased by 266 times, which enables the self-electrophoretic driven micro-nano motor to maintain stable movement at an electrolyte concentration as high as 150 mM.

[0071] Unless otherwise specified, room temperature in the present invention is calculated as 25 ± 2 °C, and normal pressure refers to one atmosphere (101.325 kPa).

[0072] All raw materials used in the examples and comparative examples of the present invention are obtained through commercial purchase.

[0073] It should be noted that the details not described in the present invention are all conventional operation means in the art and are not the focus of the present invention.

[0074] The technical solution of the present invention will be further described below through examples.

[0075] Comparative Example 1

[0076] This comparative example provides a preparation method of a silicon nanowire micro-nano motor, and the specific steps are as follows:

[0077] (1) Cleaning the silicon wafer: Mix hydrogen peroxide with a mass fraction of 30% and concentrated sulfuric acid with a mass fraction of 98% according to a volume ratio of 1:7 to obtain a cleaning solution. Place the n-type silicon wafer with a crystal type of <100> in the cleaning solution, heat it to 180 °C to clean the silicon wafer, and after that, clean it alternately with water, isopropanol, and acetone;

[0078] (2) Preparing a dot matrix pattern by lithography: The selected photoresist is AZ 5214 photoresist, and the spin coating conditions are a rotation speed of 4000 rpm, rotating for 30 s, and drying at 110 °C for 2 min. Then cover a mask plate with a pattern size of 4.5 × 4.5 cm, a dot diameter of 2 μm, and a dot pitch of 2 μm, expose for 20 s, and develop using the developer ZX-238 to obtain a dot matrix pattern; the diameter of the subsequent silicon nanowires can be controlled by controlling the diameter of the dot matrix;

[0079] (3) Wet etching of silicon nanowires: Place the silicon wafer with a dot matrix pattern in the etching solution. The etching solution is a mixed aqueous solution of HF and AgNO3. In the etching solution, the concentration of HF is 5 mol / L, and the concentration of AgNO3 is 0.02 mol / L. The volume of the used etching solution is related to the area of the silicon wafer, and the ratio is 3 mL / cm 2, the etching rate was 142 nm / min; after taking it out, the remaining photoresist was removed with acetone, washed with water, soaked in concentrated nitric acid to remove the remaining Ag, taken out, washed successively with water and isopropyl alcohol, and dried on a heating table at 80 °C; the length of the silicon nanowires can be controlled by controlling the etching time. In this comparative example, the wet etching time was 70 minutes, and the length of the obtained silicon nanowires was 10 μm; subsequent thermal oxidation etching can regulate the diameter of the silicon nanowires;

[0080] (4) Control of the diameter of silicon nanowires: Then, the thin silicon nanowires outside the array were removed by thermal oxidation and etching, and the diameter of the array was adjusted. The specific steps were as follows: The sample obtained in step (3) was thermally oxidized at 1000 °C in an oxygen atmosphere, the oxidation rate was 100 nm / h, and the time was 90 min. Then, the silicon oxide was etched with a buffered solution of hydrofluoric acid (BHF, prepared by mixing 49 wt% HF and 40 wt% NH4F aqueous solution in a volume ratio of 1:5), the rate was 100 nm / min, and the time was 5 min. The etching was repeated twice, and the diameter of the obtained silicon nanowires was 1 μm;

[0081] (5) Obtaining an insulating layer by thermal oxidation method: The sample obtained in step (4) was thermally oxidized at 900 °C in an oxygen atmosphere, and the treatment time was controlled to adjust the thickness of the insulating layer SiO2; the treatment time in this comparative example was 2 minutes, and the thickness of the insulating layer SiO2 was 5 nm;

[0082] (6) Thermal evaporation of magnetic metal Ni: The magnetic metal Ni was evaporated on the surface of the silicon nanowires by using a high-vacuum resistance thermal evaporation coating equipment to form a MIS solar cell structure, and the thickness of the metal layer was controlled by the evaporation rate and time; in this example, the evaporation rate was The evaporation time was 400 s, and the thickness of the obtained metal layer was 20 nm;

[0083] (7) Control of the catalyst layer: First, the sample obtained in step (6) was treated in an oxygen atmosphere for 300 s by using a plasma cleaner to partially oxidize the metal Ni to obtain NiO x Catalyst layer (when the thickness of the metal Ni layer is 10 - 30 nm, controlling the treatment time in an oxygen atmosphere to be 200 - 400 s can all achieve partial oxidation of the metal Ni, and the performance of the finally obtained micro-nano motor is quite the same); then, Au nanoparticles were deposited by using an ion sputtering instrument and controlled to form a discontinuous film (the reduced thickness of 2 - 5 nm is sufficient) as a co-catalyst to obtain a micro-nano motor based on the MIS solar cell structure, which is a silicon nanowire micro-nano motor.

[0084] Example 1

[0085] This embodiment provides a method for improving the ion tolerance of silicon nanowire micro-nano motors by surface-modifying ZIF-8 porous structure materials. The micro-nano motors with high ion tolerance are denoted as MIS-Au@ZIF-8, and the synthesis route is shown in Figure 1 (Obtaining a regularly arranged n-type silicon nanowire array by means of micro-nano processing; obtaining an insulating layer SiO2 by thermal oxidation method, evaporating a magnetic metal onto the surface of the Si nanowire array to form a MIS junction, and obtaining a NiO x layer by thermal oxidation method, depositing Au nanoparticles on the surface by magnetron sputtering to obtain MIS@Au silicon nanowire micro-nano motors; in-situ modifying ZIF-8 porous structure materials on the surface of the MIS@Au silicon nanowire micro-nano motors), and the specific steps are as follows:

[0086] (1) Cleaning the silicon wafer: Mix hydrogen peroxide with a mass fraction of 30% and concentrated sulfuric acid with a mass fraction of 98% according to a volume ratio of 1:7 to obtain a cleaning solution. Place an n-type silicon wafer with a crystal type of <100> in the cleaning solution, heat it to 180 °C to clean the silicon wafer, and after completion, clean it alternately with water, isopropanol, and acetone;

[0087] (2) Preparing a dot matrix pattern by photolithography: The selected photoresist is AZ 5214 photoresist, and the spin-coating conditions are: rotation speed of 4000 rpm, rotation for 30 s, drying at 110 °C for 2 min, then covering a mask plate with a pattern size of 4.5×4.5 cm, dot diameter of 2 μm, and dot spacing of 2 μm, exposing for 20 s, and developing with a developer ZX-238 to obtain a dot matrix pattern; the diameter of the subsequent silicon nanowires can be controlled by controlling the diameter of the dot matrix;

[0088] (3) Wet etching of silicon nanowires: Place the silicon wafer with a dot matrix pattern in an etching solution, which is a mixed aqueous solution of HF and AgNO3. In the etching solution, the concentration of HF is 5 mol / L, and the concentration of AgNO3 is 0.02 mol / L. The volume of the used etching solution is related to the area of the silicon wafer, and the ratio is 3 mL / cm 2 , and the etching rate is 142 nm / min; after taking it out, remove the remaining photoresist with acetone, wash it with water, soak it in concentrated nitric acid to remove the remaining Ag, take it out, wash it successively with water and isopropanol, and dry it on a heating table at 80 °C; the length of the silicon nanowires can be controlled by controlling the etching time. In this embodiment, the wet etching time is 70 minutes, and the obtained silicon nanowires have a length of 10 μm; subsequent thermal oxidation etching can regulate the diameter of the silicon nanowires;

[0089] (4) Control of the diameter of silicon nanowires: Subsequently, the thin silicon nanowires outside the array are removed by thermal oxidation and etching, and the diameter of the array is adjusted. The specific steps are as follows: The sample obtained in step (3) is thermally oxidized at 1000 °C in an oxygen atmosphere with an oxidation rate of 100 nm / h for 90 min. Then, the silicon dioxide is etched with a buffered hydrofluoric acid solution (BHF, prepared by mixing 49 wt% HF and 40 wt% NH4F aqueous solution in a volume ratio of 1:5) at a rate of 100 nm / min for 5 min. The etching is repeated twice, and the diameter of the obtained silicon nanowires is 1 μm;

[0090] (5) Obtaining an insulating layer by thermal oxidation: The sample obtained in step (4) is thermally oxidized at 900 °C in an oxygen atmosphere, and the thickness of the insulating layer SiO2 is adjusted by controlling the processing time; the processing time in this embodiment is 2 minutes, and the thickness of the insulating layer SiO2 is 5 nm;

[0091] (6) Thermal evaporation of magnetic metal Ni: The magnetic metal Ni is evaporated onto the surface of the silicon nanowires by using a high-vacuum resistance thermal evaporation coating device to form a MIS solar cell structure, and the thickness of the metal layer is controlled by the evaporation rate and time; in this embodiment, the evaporation rate is The evaporation time is 400 s, and the thickness of the obtained metal layer is 20 nm;

[0092] (7) Control of the catalyst layer: First, the sample obtained in step (6) is treated in an oxygen atmosphere for 300 s by using a plasma cleaner to partially oxidize the metal Ni to obtain NiO x Catalyst layer (when the thickness of the metal Ni layer is 10 - 30 nm, controlling the processing time in an oxygen atmosphere to be 200 - 400 s can achieve partial oxidation of the metal Ni, and the performance of the finally obtained micro-nano motor is quite comparable); then, Au nanoparticles are deposited by using an ion sputtering instrument and controlled to form a discontinuous film (the reduced thickness is 2 - 5 nm) as a co-catalyst to obtain a micro-nano motor based on the MIS solar cell structure, which is a silicon nanowire micro-nano motor;

[0093] (8) Modified metal-organic framework pore structure material: First, the micro-nano motor based on the MIS solar cell structure was subjected to oxygen plasma treatment for hydroxyl functionalization to obtain a pretreated micro-nano motor; Subsequently, 4.105 g (0.05 mol) of dimethylimidazole was dissolved in 50 mL of deionized water to obtain an aqueous dimethylimidazole solution; 0.183 g (0.0008 mol) of zinc acetate dihydrate was dissolved in 10 mL of deionized water to obtain a soluble zinc salt aqueous solution; The pretreated micro-nano motor was immersed in the aqueous dimethylimidazole solution for 3 minutes, and then the soluble zinc salt aqueous solution was poured into the dimethylimidazole solution, and the reaction was carried out at room temperature and atmospheric pressure for 40 min. After the reaction, it was naturally cooled to room temperature, and the micro-nano motor was thoroughly washed with deionized water and methanol, and dried to obtain a silicon nanowire micro-nano motor (MIS-Au@ZIF-8) based on the ZIF-8 pore structure material.

[0094] The scanning electron microscope (SEM) image of the silicon nanowire micro-nano motor based on the ZIF-8 pore structure material in this example is shown in Figure 2 , and it can be seen that: the micro-nano motors are regularly arranged, with a length of about 15 μm and a diameter of 1.5 μm. It can be clearly seen that ZIF-8 grows uniformly on the MIS@Au silicon nanowires, forming a dense and uniform ZIF-8 pore structure material. The successful formation of this pore structure material provides stronger ionic conductivity and stability for the micro-nano motor, creating favorable conditions for improving its salt tolerance performance.

[0095] The EDX elemental distribution map of the silicon nanowire micro-nano motor based on the ZIF-8 pore structure material in this example is shown in Figure 3 , and it can be seen that elements such as Si, Ni, Au, and Zn are uniformly distributed on the surface of the silicon nanowires.

[0096] The salt tolerance of the silicon nanowire micro / nano motors based on ZIF-8 porous structure materials in this example and the silicon nanowire micro / nano motors without any MOF material modification in Comparative Example 1 was tested. The specific method is as follows: The material to be tested was placed on a conductivity stage with a glass slide to measure the real-time conductivity in the experiment for testing the salt tolerance of the silicon nanowire micro / nano motors based on ZIF-8 porous structure materials prepared in Example 1. This glass slide has a rectangular liquid reservoir (16 mm × 25 mm × 1 mm) with numbered markings made of a 20-nm-thick titanium layer. In addition, there are two pairs of gold electrodes (15 mm × 4 mm) in the liquid reservoir, and the distance between the electrodes is 100 μm, which is used to measure the conductivity of the medium. Before the experiment, the glass slide was thoroughly cleaned with a solution of NH3·H2O:H2O2:H2O = 1:1:5 (v:v:v), and each slide was calibrated with a series of NaCl solutions with known concentrations (concentration range from 0 to 200 mM). The silicon nanowire micro / nano motors based on ZIF-8 porous structure materials / silicon nanowire micro / nano motors were carefully scraped off from the substrate with a blade and dispersed into a ferrocene methanol solution to measure their migration behavior. The conductivity of the solution was adjusted by adding a high concentration of NaCl to the ferrocene methanol solution, and once the reading of the conductivity meter was stable, the measurement was carried out.

[0097] The salt tolerance curves of the silicon nanowire micro / nano motors based on ZIF-8 porous structure materials in this example and the silicon nanowire micro / nano motors in Comparative Example 1 are as Figure 4 shown. Since the propulsion of silicon nanowire micro / nano motors depends on self-electrophoresis, in a high-salt environment, silicon nanowire micro / nano motors driven by self-electrophoresis usually lose their motility. According to the prediction of the Helmholtz-Smoluchowski theory, this phenomenon stems from the electric field shielding effect, resulting in the compression of the Debye layer from about 100 nm to about 1 nm. This compression inhibits the electrophoretic motion, thereby reducing the propulsion efficiency of the silicon nanowire micro / nano motors. In contrast, as a porous scaffold, the ZIF-8 porous structure material provides an ion-conducting channel, preventing the collapse of the Debye layer, and thus maintaining the self-electrophoresis mechanism. Therefore, the ZIF-8 porous structure material significantly improves the ion tolerance of the silicon nanowire micro / nano motors by enhancing the electroosmotic flow of the silicon nanowire micro / nano motors. Calculated from the salt tolerance curve, the EI 50 value of the silicon nanowire micro / nano motors in Comparative Example 1 is 0.020 ± 0.001 mM, while the EI 50 value of the silicon nanowire micro / nano motors based on ZIF-8 porous structure materials in this example is 5.322 ± 0.271 mM, which is increased by nearly 266 times. This trend indicates that first reducing the size of the micro / nano motors and then modifying the MOF porous structure material helps to enhance their stability and propulsion ability in a high-salt environment.

[0098] To further evaluate its adaptability in complex biological environments, the micro-nano motor based on the ZIF-8 porous structure material was placed in a PBS solution, and its movement performance in an artificial blood vessel under near-infrared light driving was tested while covering 3 mm thick muscle tissue. The schematic diagram of the movement process of the silicon nanowire micro-nano motor based on the ZIF-8 porous structure material in the artificial blood vessel under 980 nm near-infrared light driving in this embodiment is as Figure 5 shown. The results show that the micro-nano motor based on the ZIF-8 porous structure material can be effectively propelled under 980 nm near-infrared light irradiation and can accurately pass through these artificial blood vessels under magnetic field guidance. This indicates that the micro-nano motor modified with the MOF porous structure material has the ability to move stably in a simulated biological environment.

[0099] Comparative Example 2

[0100] This comparative example provides a method for preparing a TiO2-Pt micro-nano motor (TiO2-Pt), and the specific steps are as follows:

[0101] Dissolve 5 mL of TTIP in 20 mL of ethanol solution. In another beaker, prepare a mixed solution of 50 mL of absolute ethanol + 2 mL of deionized water + 1 mL of glacial acetic acid. Slowly drop the TTIP solution into the mixed solution and stir for 2 h to fully hydrolyze and condense it to form a stable TiO2 sol. Subsequently, transfer the sol to a reaction kettle and react at 150 °C for 12 h. After the reaction is completed, take out the precipitate, wash it three times with ethanol and deionized water, and dry it in vacuum at 80 °C for 12 h. Finally, calcine it for 2 h to obtain crystalline TiO2 spheres. The TiO2 spheres were evenly dispersed on the surface of the silicon wafer by the film fishing method. First, disperse the spheres in ethanol and ensure uniform distribution of the spheres by ultrasonic treatment. Then, immerse the clean silicon wafer in the ethanol solution, and by means of surface tension and volatilization, adsorb the dispersed TiO2 spheres from the solution onto the surface of the silicon wafer. Subsequently, sputter platinum nanoparticles on its surface by magnetron sputtering to finally obtain the TiO2-Pt micro-nano motor.

[0102] Example 2

[0103] This example provides a method for improving the ion tolerance of a TiO2-Pt micro-nano motor by surface modification of a ZIF-8 porous structure material. The obtained micro-nano motor with high ion tolerance is denoted as TiO2-Pt@ZIF-8, and the specific steps are as follows:

[0104] The preparation method of the TiO2-Pt micro-nano motor is the same as that of Comparative Example 2. First, the TiO2-Pt micro-nano motor is treated with oxygen plasma for hydroxyl functionalization to obtain a pretreated micro-nano motor. Subsequently, 4.105 g (0.05 mol) of dimethylimidazole is dissolved in 50 mL of deionized water to obtain an aqueous dimethylimidazole solution. 0.183 g (0.0008 mol) of zinc acetate dihydrate is dissolved in 10 mL of deionized water to obtain a soluble zinc salt aqueous solution. The pretreated micro-nano motor is immersed in the aqueous dimethylimidazole solution for 3 minutes. Subsequently, the soluble zinc salt aqueous solution is poured into the aqueous dimethylimidazole solution, and the reaction is carried out at room temperature and normal pressure for 40 min. After the reaction is completed, it is naturally cooled to room temperature, and the micro-nano motor is thoroughly washed with deionized water and methanol, and dried to obtain the TiO2-Pt@ZIF-8 micro-nano motor.

[0105] Comparative Example 3

[0106] This comparative example provides a preparation method of a SiO2-Pt micro-nano motor (SiO2-Pt), and the specific steps are as follows:

[0107] 20 mL of deionized water is added to 80 mL of absolute ethanol, and 6 mL of ammonia water is added dropwise as a catalyst. Under stirring, 4 mL of tetraethyl orthosilicate is slowly added, and the reaction is continued for stirring for 24 h. The SiO2 particles gradually grow and stabilize. The residual reactants are removed by centrifugation and washing, and the SiO2 spheres can be obtained after drying. The SiO2 spheres are uniformly dispersed on the surface of the silicon wafer by the film fishing method. First, the spheres are dispersed in ethanol, and ultrasonic treatment is used to ensure that the spheres are evenly distributed. Then, the clean silicon wafer is immersed in the ethanol solution, and with the help of surface tension and volatilization, the dispersed SiO2 spheres are adsorbed onto the surface of the silicon wafer from the solution. Subsequently, platinum nanoparticles are sputtered on its surface by magnetron sputtering to finally obtain the SiO2-Pt micro-nano motor.

[0108] Example 3

[0109] This example provides a method for improving the ion tolerance of a SiO2-Pt micro-nano motor by surface-modifying a ZIF-8 pore structure material. The obtained micro-nano motor with high ion tolerance is denoted as SiO2-Pt@ZIF-8, and the specific steps are as follows:

[0110] The preparation method of the SiO2-Pt micro-nano motor was the same as that of Comparative Example 3. First, the SiO2-Pt micro-nano motor was treated with oxygen plasma for hydroxyl functionalization to obtain a pretreated micro-nano motor. Subsequently, 4.105 g (0.05 mol) of dimethylimidazole was dissolved in 50 mL of deionized water to obtain an aqueous dimethylimidazole solution. 0.183 g (0.0008 mol) of zinc acetate dihydrate was dissolved in 10 mL of deionized water to obtain a soluble zinc salt aqueous solution. The pretreated micro-nano motor was immersed in the aqueous dimethylimidazole solution for 3 minutes. Subsequently, the soluble zinc salt aqueous solution was poured into the aqueous dimethylimidazole solution, and the reaction was carried out at room temperature and normal pressure for 40 min. After the reaction was completed, it was naturally cooled to room temperature, and the micro-nano motor was thoroughly washed with deionized water and methanol, and dried to obtain the SiO2-Pt@ZIF-8 micro-nano motor.

[0111] To verify the universality of the surface porous material ZIF-8 in enhancing the ion tolerance of micro-nano motors, the ZIF-8 porous structure material was applied to two other widely studied electrolyte self-diffusiophoretic micro-nano motors: TiO2-Pt micro-nano motors and SiO2-Pt micro-nano motors (see Examples 2 and 3 for details). The SEM images of the TiO2-Pt@ZIF-8 micro-nano motors in Example 2 and the SiO2-Pt@ZIF-8 micro-nano motors in Example 3 are as Figure 6 shown, and the results demonstrate the successful preparation of these micro-nano motors, all of which have a Janus structure. Subsequently, the micro-nano motors of Examples 2 to 3 and Comparative Examples 2 to 3 were transferred to solutions with different salt concentrations (0 to 4 mM), and migration tests were carried out under a microscope to further evaluate their salt tolerance performance.

[0112] The salt tolerance curves of the micro-nano motors modified with the ZIF-8 porous structure material and the micro-nano motors without the ZIF-8 porous structure material in ferrocene methanol solutions with different salt concentrations are as Figure 7 shown. It can be seen that after the surface is modified with the ZIF-8 porous structure material, these two micro-nano motors (TiO2-Pt micro-nano motors and SiO2-Pt micro-nano motors) also show significant improvement in ion tolerance, further verifying the effectiveness of the ZIF-8 porous structure material in improving the salt tolerance performance of various self-electrophoresis-driven micro-nano motors.

[0113] The above experimental results not only prove the applicability of the ZIF-8 porous structure material in different self-electrophoresis-driven micro-nano motor systems, but also provide a strong basis for further research and optimization of the performance of self-electrophoresis-driven micro-nano motors in complex biological environments.

[0114] To further verify the drug-loading ability of the self-electrophoretic driven micro-nano motor after surface modification with MOF pore structure materials, taking the micro-nano motor of silicon nanowires based on ZIF-8 pore structure materials in Example 1 loaded with doxorubicin (DOX) (abbreviated as "drug-loaded micro-nano motor") as an example, the following experiment was carried out: The micro-nano motor with surface-modified ZIF-8 pore structure materials was placed in a PBS solution with a DOX concentration of 75 μg / mL and soaked for 24 h to allow DOX to enter the pores of ZIF-8 by diffusion. The sample was gently washed with deionized water to remove the unadsorbed drugs on the surface. The pH-responsive drug release diagram of the above drug-loaded micro-nano motor is as Figure 8 shown. It can be seen that for the drug-loaded micro-nano motor in the simulated tumor environment (pH = 7.4) and the slightly acidic environment (pH = 5.5), the release of the drug DOX shows obvious pH responsiveness. Specifically, in the pH = 7.4 environment, the drug release is slow, while in the acidic environment of pH = 5.5, the drug release is significantly accelerated. This pH-responsive release characteristic enables the self-electrophoretic driven micro-nano motor with surface-modified MOF pore structure materials to achieve more precise drug release in the tumor microenvironment.

[0115] Example 4

[0116] This example provides a method for improving the ion tolerance of silicon nanowire micro-nano motors by surface modification with UiO-66 pore structure materials. The obtained micro-nano motors with high ion tolerance are denoted as MIS-Au@UiO-66, and the specific steps are as follows:

[0117] Perform oxygen plasma treatment on the self-electrophoretic driven micro-nano motor to obtain a pretreated self-electrophoretic driven micro-nano motor;

[0118] Place the pretreated self-electrophoretic driven micro-nano motor in a solution and heat it at 145 °C for 48 hours. After the reaction is completed, cool it naturally to room temperature. Wash the self-electrophoretic driven micro-nano motor 3 times with DMF (N,N-dimethylformamide) and ethanol to remove the unreacted precursors, and then dry it in vacuum at 60 °C for 12 hours to obtain the micro-nano motors with high ion tolerance MIS-Au@UiO-66.

[0119] Example 5

[0120] This example provides a method for improving the ion tolerance of silicon nanowire micro-nano motors by surface modification with MIL-53(Al) pore structure materials. The obtained micro-nano motors with high ion tolerance are denoted as MIS-Au@MIL-53(Al), and the specific steps are as follows:

[0121] Perform oxygen plasma treatment on the self-electrophoretic driven micro-nano motor to obtain a pretreated self-electrophoretic driven micro-nano motor;

[0122] Aluminum nitrate nonahydrate and terephthalic acid were dissolved in deionized water at a molar ratio of 1:1. After stirring until dissolved, the resulting solution was transferred to a high-pressure reactor. The pretreated self-electrophoretic-driven micro-nano motor was placed in the solution and reacted at 150 °C for 24 hours. Then it was washed with deionized water and methanol and dried under vacuum at 80 °C to obtain the micro-nano motor MIS-Au@MIL-53(Al) with high ion tolerance.

[0123] The morphology diagrams of different types of MOF pore structure materials grown on the silicon nanowire micro-nano motors in Example 4 and Example 5 are as Figure 9 shown. It can be seen that compared with the ZIF-8 pore structure material, the MOF layer formed by the growth of the UiO-66 pore structure material on the surface of the micro-nano motor is relatively loose and has a large grain interval. The MIL-53(Al) pore structure material forms a tip structure that is not easily loose. Compared with the ZIF-8 pore structure material and the UiO-66 pore structure material, the MIL-53(Al) pore structure material is more conducive to enhancing the drug loading and release performance. The special structure of the MIL-53(Al) pore structure material enables it to have good performance in applications such as dynamic detection and environmental monitoring.

[0124] The above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A method for improving the ion tolerance of a self-electrophoretic driven micro-nano motor, characterized in that: After the self-electrophoresis driven micro-nano motor is treated with oxygen plasma, a metal organic framework pore structure material is modified on the surface of the self-electrophoresis driven micro-nano motor.

2. The method for improving the ion tolerance of a self-electrophoretic driven micro-nano motor according to claim 1, characterized in that: The metal organic framework pore structure material is selected from one of ZIF-8, UiO-66 and MIL-53 (Al).

3. The method for improving the ion tolerance of a self-electrophoretic driven micro-nanomotor according to claim 2, characterized in that: When the metal organic framework pore structure material is selected from ZIF-8, the method comprises the following steps: treating the self-electrophoretic driven micro-nano motor with oxygen plasma to obtain a pre-treated self-electrophoretic driven micro-nano motor; First, the pretreated self-electrophoretic driven micro-nanomotor is immersed in a dimethylimidazole aqueous solution for 3 minutes, and then a soluble zinc salt aqueous solution is added to react for 30-60 minutes. After the reaction is completed, it is naturally cooled to room temperature, and the self-electrophoretic driven micro-nanomotor is cleaned and dried.

4. The method for improving the ion tolerance of a self-electrophoretic driven micro-nano motor according to claim 3, characterized in that: The molar ratio of the dimethylimidazole to the soluble zinc salt is 500:

8.

5. The method for improving the ion tolerance of a self-electrophoretic driven micro-nano motor according to claim 2, characterized in that: When the metal organic framework pore structure material is selected from UiO-66, the method comprises the following steps: treating the self-electrophoretic driven micro-nano motor with oxygen plasma to obtain a pre-treated self-electrophoretic driven micro-nano motor; 0.25 mmol zirconium tetrachloride, 0.25 mmol terephthalic acid and 30 mL N,N-dimethylformamide were stirred evenly and poured into a reactor. The pretreated self-electrophoretic micro-nano motor was placed in the solution and heated at 145°C for 48 hours. After the reaction was completed, it was naturally cooled to room temperature and the self-electrophoretic micro-nano motor was cleaned and dried.

6. The method for improving the ion tolerance of a self-electrophoretic driven micro-nano motor according to claim 2, characterized in that: When the metal organic framework pore structure material is selected from MIL-53 (Al), the method comprises the following steps: treating the self-electrophoretic driven micro-nano motor with oxygen plasma to obtain a pre-treated self-electrophoretic driven micro-nano motor; Aluminum nitrate nonahydrate and terephthalic acid were dissolved in deionized water at a molar ratio of 1:1, and stirred until dissolved. The resulting solution was transferred to a high-pressure reactor, and the pretreated self-electrophoretic driven micro-nano motor was placed in the solution. After reacting at 150°C for 24 hours, the solution was washed with deionized water and methanol, and vacuum dried at 80°C.

7. The method for improving the ion tolerance of a self-electrophoretic driven micro-nano motor according to claim 1, characterized in that: The self-electrophoretic driven micro-nano motor includes a silicon-based self-electrophoretic driven micro-nano motor or a titanium-based self-electrophoretic driven micro-nano motor.

8. The method for improving the ion tolerance of a self-electrophoretic driven micro-nano motor according to claim 7, characterized in that: The silicon-based self-electrophoretic driven micro-nano motor comprises a silicon nanowire micro-nano motor or a SiO2-Pt micro-nano motor; And / or, the titanium-based self-electrophoretic driven micro-nano motor is selected from TiO2-Pt micro-nano motor.

9. A self-electrophoretic driven micro-nano motor with high ion tolerance, characterized in that: Prepared according to the method according to any one of claims 1 to 8, the self-electrophoresis driven micro-nano motor with high ion tolerance has a salt tolerance concentration of up to 150 mM.

10. Use of the self-electrophoretic driven micro-nanomotor with high ion tolerance as claimed in claim 9 in micro-region object transport materials, targeted drug-carrying materials or optical nerve modulation materials.

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