Method for preparing double-sided Janus nanomotor based on polyacrylic acid constructing eccentric structure

Abstract

The application provides a method for preparing a double-faced Janus nanomotor based on polyacrylic acid (PAA) constructed eccentric structure, and belongs to the field of nanodevices.The method comprises the following steps: preparing an eccentric structure by adjusting electrostatic adsorption and coordination bonding between spherical nanoparticles and PAA; and based on the eccentric structure, performing asymmetric modification on the surface of the spherical nanoparticles.The method has the advantages of simple preparation process, mild reaction condition and ability to realize macro-preparation, and helps to accelerate the industrialization process of the nanomotor, and the method can be expanded to various nanomaterial systems, thereby providing a new idea for the preparation of the double-faced Janus nanomotor.

Description

Technical Field

[0001] This invention relates to the field of nanodevice technology, specifically to a method for fabricating Janus nanomotors based on an eccentric structure constructed from polyacrylic acid (PAA). Background Technology

[0002] Nanomotors are nanodevices capable of converting other forms of energy into their own kinetic energy. Due to their nanoscale size, their structure is the most crucial factor determining their motion performance. Among the reported nanomotor structures, Janus particles possess two distinct surfaces. One surface can be modified with catalytic components, where the decomposition of the catalytic substrate creates an asymmetric field around it, generating a greater driving force. The other surface can be modified with non-functional molecules according to application requirements. Based on these advantages, Janus particles are widely used to construct nanomotors. However, when the size of nanoparticles shrinks to the nanoscale, constructing asymmetric structures on their surfaces presents significant challenges.

[0003] Currently, the main methods for fabricating Janus nanomotors include physical deposition (PDE) and chemical colloid methods. PDE involves asymmetrically depositing a thin layer of the target material onto a substrate surface under vacuum or partial vacuum conditions. This method is suitable for fabricating micron-sized Janus particles but requires expensive equipment. Chemical colloid methods combine different building blocks, including atoms, molecules, and even various compositions of nanostructures, to create the desired nanostructure. This method is suitable for fabricating small-sized asymmetric nanoparticles, requires simple equipment, and allows for flexible control of the nanoparticle composition.

[0004] The inventors' team previously developed a chemical synthesis method for preparing small-sized asymmetric gold nanomotors by utilizing the differences in surface properties between polystyrene (PS) and gold nanoparticles (paper, ACS Nano (2023, 17, 6, 6023–6035). This method can be used to prepare small-sized Janus-like gold nanomotors with uniform particle size. By controlling the size of the gold nanospheres, nanomotors with a diameter of 30–100 nm can be obtained. However, this method involves cumbersome reaction steps, requires a large amount of organic solvent, is difficult to achieve large-scale preparation, and cannot be extended to other material systems. Summary of the Invention

[0005] In view of the technical problems existing in the background art, the present invention develops a method for preparing Janus nanomotors by constructing an eccentric structure using polyacrylic acid, aiming to solve the technical problems such as the cumbersome preparation of Janus nanoparticles, the limitation of material systems, and the inability to prepare them in large quantities.

[0006] The specific technical solution of the present invention is as follows:

[0007] A method for fabricating Janus nanomotors based on polyacrylic acid with an eccentric structure includes the following steps:

[0008] S1. An eccentric structure was prepared by utilizing the electrostatic adsorption and coordination bonding between spherical nanoparticles and PAA.

[0009] S2. Based on the eccentric structure, the surface of spherical nanoparticles is asymmetrically modified.

[0010] Preferably, in the above method, step S1 specifically involves: preparing a reaction solution containing spherical nanoparticles and PAA, adjusting the pH to 7.0±0.5 with alkali to allow PAA to self-assemble on the surface of the spherical nanoparticles, and then adding isopropanol (IPA) dropwise to partially coat the spherical nanoparticles with PAA. In this step, by adding alkali to adjust the reaction environment to neutral, PAA self-assembles on the surface of the spherical nanoparticles using electrostatic adsorption and coordination bonding to form a core-shell structure. Then, isopropanol is added dropwise to gradually adjust the proportion of isopropanol, gradually squeezing the spherical nanoparticles out of the core-shell structure, allowing PAA to partially coat the nanoparticles and forming an eccentric structure.

[0011] More preferably, in the above method, the alkaline solution is one or more of ammonia, sodium hydroxide, potassium hydroxide, sodium carbonate, sodium bicarbonate, and triethylamine.

[0012] More preferably, in the above method, the reaction solution in step S1 uses water as the solvent, and the volume ratio of water to isopropanol is 1:(5~50). Experiments have shown that the amount of isopropanol used in this step is crucial to the successful construction of the eccentric structure. Within this range, by adjusting the ratio of water to isopropanol in the reaction system, eccentric nanoparticles with different degrees of eccentricity can be constructed.

[0013] More preferably, in the above method, after adjusting the pH with alkali, ultrasound can promote the self-assembly of PAA on the surface of spherical nanoparticles.

[0014] In the above method, the spherical nanoparticles include, but are not limited to, elemental, oxide, or sulfide nanoparticles of metallic elements such as gold, silver, palladium, platinum, manganese, iron, cerium, titanium, aluminum, and zinc; inorganic non-metallic nanoparticles (such as nano-silica); and organic nanoparticles. Furthermore, the spherical nanoparticles can be hollow, solid, or porous. The diameter of the spherical nanoparticles is preferably 10-500 nm. For different spherical nanoparticles, pretreatment can be performed to better construct the eccentric structure. For example, in one embodiment of the present invention, the surface of nano-Fe3O4 is modified with carboxylation. In another embodiment of the present invention, the surface of nano-silica is modified with amination.

[0015] In the above method, asymmetric modification specifically refers to performing multiple modifications on the surface of spherical nanoparticles in different regions, resulting in spherical nanoparticles with an asymmetric structure. It is understood that among the multiple modifications, at least one modifies a component with catalytic function.

[0016] Preferably, in the above method, step S2 includes the following steps:

[0017] S21. Modify one side of the exposed nanoparticles in the eccentric structure with molecules that do not have catalytic function;

[0018] S22. After removing PAA from the eccentric structure, modify the other side of the nanoparticle with a catalytic component to obtain the Janus nanomotor.

[0019] In the above method, the modification in step S21 can be achieved through covalent bonding or electrostatic adsorption. In specific embodiments, different functional molecules can be modified according to actual needs. For example, in some embodiments of the present invention, carboxyl polyethylene glycol is covalently coupled to the surface of exposed gold nanoparticles in Au-PAA (gold-polyacrylic acid) eccentric particles.

[0020] Preferably, in the above method, the catalytic component is a biological enzyme, including but not limited to urease, catalase, glucose peroxidase, arginase, lipoprotein lipase, lipase, galactosidase, transaminase, decarboxylase, and carbonic anhydrase. This component catalyzes the decomposition of the substrate, creating an asymmetric field around the nanomotor, thereby generating a driving force that enables the nanomotor to move effectively. For example, in some embodiments of the present invention, the catalytic component is urease, and the resulting nanomotor can be effectively driven in human urea concentrations (~10 mM). It is understood that one or more catalytic components can be modified onto the Janus nanomotor.

[0021] Preferably, in the above method, the PAA in the eccentric structure is removed by washing with water. Taking advantage of PAA's water solubility, a simple water wash is sufficient to remove PAA, allowing for further modification of the newly exposed nanoparticle surface after PAA removal.

[0022] It is understood that the Janus nanospherical motor prepared by the method of this invention also falls within the scope of protection of this invention. The Janus nanomotor has broad application prospects, such as serving as a drug delivery carrier to cross various biological barriers and improve drug delivery efficiency.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] This invention utilizes PAA to construct an eccentric structure, and then performs asymmetric modifications on the eccentric structure to obtain Janus nanomotors. This method has advantages such as simple preparation process, mild reaction conditions, and the ability to achieve large-scale preparation, which helps to accelerate the industrialization process of nanomotors. More importantly, this method is versatile and can be applied not only to the preparation of gold nanomotors, but also to various nanomaterial systems, such as nano-silica and nano-ferric oxide, providing a new approach for the preparation of Janus nanomotors. Attached Figure Description

[0025] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the present invention will be briefly described below. Obviously, the drawings described below are merely some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0026] Figure 1 This is a schematic diagram illustrating the structure and fabrication process of the Janus nanomotor in an embodiment of the present invention;

[0027] Figure 2 The images show the SEM and UV spectra of the gold nanoparticles used in the embodiments of this invention.

[0028] Figure 3 This is a characterization diagram of the Au-PAA eccentric structure prepared in the embodiments of the present invention;

[0029] Figure 4 The images show transmission electron microscopy (TEM) images and elemental analysis diagrams of the Janus nanomotor prepared in this embodiment of the invention.

[0030] Figure 5 The diagram shows the motion trajectory, mean square displacement, and diffusion coefficient of the Janus nanomotor prepared in the embodiments of the present invention in urea solutions of different concentrations as a function of urea concentration. Detailed Implementation

[0031] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the technical solution of the present invention and are therefore intended to limit the scope of protection of the present invention.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention; the terms “comprising” and “having”, and any variations thereof, in the specification and claims of this invention are intended to cover non-exclusive inclusion; the term “multiple” in the specification of this invention refers to two or more.

[0033] In the field of nanomotors, the Janus nanomotor holds a significant position due to its unique motion and loading capabilities. However, current methods for preparing Janus nanomotors either suffer from expensive equipment, cumbersome procedures, difficulty in large-scale production, or lack of universality, thus limiting the industrialization of Janus nanomotors. To address the technical challenges of complex and costly preparation methods for Janus nanomotors, this invention provides a method for preparing Janus nanomotors based on an eccentric structure constructed using polyacrylic acid (PAA). This method first utilizes PAA to construct an eccentric structure on spherical nanoparticles, and then asymmetrically modifies the motor based on the eccentric structure. This method is applicable to various nanomaterial systems, and the preparation method is simple, the reaction conditions are mild, and it enables large-scale production.

[0034] This invention provides a method for fabricating Janus nanomotors based on an eccentric structure constructed from polyacrylic acid, comprising the following steps:

[0035] S1. An eccentric structure was prepared by utilizing the electrostatic adsorption and coordination bonding between spherical nanoparticles and PAA.

[0036] S2. Based on the eccentric structure, the surface of the spherical nanoparticles has at least two different modifications that are asymmetric.

[0037] In the above preparation method, step S1 specifically involves: establishing a reaction system containing spherical nanoparticles and PAA; and then adding alkali and IPA sequentially to allow PAA and spherical nanoparticles to form an eccentric structure through electrostatic adsorption and coordination bonding. In this step, the amount of IPA is crucial to the successful construction of the eccentric structure, and by adjusting the amount of IPA in the reaction system, eccentric nanoparticles with different degrees of eccentricity can be constructed.

[0038] In the above preparation method, the surface of the spherical nanoparticles is modified with at least one catalytic component. Other modifications can be functional molecules such as PEG, amino groups, etc. The specific modification type and the catalytic component used can be determined according to actual needs.

[0039] The following are some specific embodiments. It should be noted that the embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0040] Example 1

[0041] like Figure 1As shown, this example provides a Janus nanomotor, and its fabrication method includes the following steps:

[0042] (1) Preparation of gold nanoparticles.

[0043] The preparation of 90 nm diameter gold nanospheres using the sodium citrate reduction method is an existing technique and will not be described in detail here. Figure 2 A and 2B are the SEM and UV spectra of the Au nanoparticles in this example, respectively, showing that they have good uniformity.

[0044] (2) Construction of eccentric structure.

[0045] At room temperature (22 °C), PAA and Au nanoparticles were added to water, with PAA concentration of 2 mg / mL and Au nanoparticle concentration of 605 mg / L. The pH was adjusted to 7.0 with NH3•H2O, and the mixture was sonicated for 15 min. Isopropanol, twice the volume of water, was slowly added dropwise to the mixture, and the mixture was stirred at room temperature for 2 hours (335 rpm). Then, isopropanol, four times the volume of water, was slowly added dropwise to the mixture, and the mixture was stirred at room temperature for 2 hours (535 rpm) to obtain asymmetric Au-PAA eccentric particles.

[0046] (3) Preparation of Janus nanomotor.

[0047] COOH-PEG-SH (PEG in 157-fold excess) was coupled onto the surface of exposed gold nanoparticles of the eccentric Au-PAA particle. Specifically, a 10 mg / mL aqueous solution of COOH-PEG-SH (1000 Da) was prepared. 1 mL of Au-PAA sample was taken, and 20 μL of COOH-PEG-SH was added to it. The mixture was then shaken overnight at 25°C.

[0048] The PAA layer was removed by washing with water, and then mPEG-SH (PEG in excess by 200 times) was first coupled onto the newly exposed gold nanoparticle surface. The specific procedure was as follows: after washing three times with deionized water, the nanoparticles were dispersed in deionized water and ultrasonically dispersed evenly; a 10 mg / mL mPEG-SH aqueous solution (2000 Da) was prepared, and 50 μL of the mPEG-SH aqueous solution was added to each tube and shaken overnight at 25°C.

[0049] Finally, urease (8000 Da, enzyme excess 2000-fold) was coupled. The specific procedure was as follows: the obtained COOH-Au-mPEG solution was washed three times with water and dispersed in PBS buffer (pH=7.4), and 240 μL was transferred to a centrifuge tube; NHS (9.2072 mg / mL) and EDC (15.336 mg / mL) in a volume ratio (v:v = 2:1) were rapidly added sequentially to the COOH-Au-mPEG solution, and the mixture was shaken at 25°C for 30 min; then 80 μL of 20 mg / mL urease solution was added, and the reaction was carried out overnight at 25°C.

[0050] Example 2

[0051] This example provides a Janus nanomotor with the same structure as in Example 1, but the preparation method includes the following steps:

[0052] (1) Preparation of gold nanoparticles.

[0053] The sodium citrate reduction method was also used to prepare gold nanospheres. However, unlike Example 1, the diameter of the gold nanospheres obtained in this example was 50 nm. Figure 2 C and 2D are the SEM and UV spectra of the Au nanoparticles in this example, respectively, showing that they have good uniformity.

[0054] (2) Construction of eccentric structure.

[0055] At room temperature (22 °C), PAA and Au nanoparticles were added to water, with PAA concentration of 20 mg / mL and Au nanoparticle concentration of 605 mg / L. The pH was adjusted to 7.0 with NH3•H2O, and the mixture was sonicated for 15 min. Isopropanol with a volume twice that of water was slowly added dropwise to the mixture, and the mixture was stirred at room temperature for 2 hours (335 rpm). Then, isopropanol with a volume four times that of water was slowly added dropwise to the mixture, and the mixture was stirred at room temperature for 2 hours (535 rpm) to obtain asymmetric Au-PAA eccentric particles.

[0056] (3) The preparation of Janus nanomotor is the same as step (3) in Example 1.

[0057] Example 3

[0058] This example provides a Janus nanomotor, which differs from Example 1 in that its nanoparticles are surface-aminated SiO2 nanoparticles, and its preparation method includes the following steps:

[0059] (1) Preparation of surface-aminated SiO2 nanoparticles.

[0060] First, SiO2 nanoparticles with an average particle size of 100 nm were prepared using the classic Stöber method.

[0061] Secondly, the SiO2 nanoparticles were modified. Specifically, SiO2 nanoparticles were dispersed in an ethanol solution, followed by the addition of 3-aminopropyltriethoxysilane (APTES). The mixture was magnetically stirred at room temperature to achieve amino functionalization modification of the SiO2 nanoparticle surface. After washing with ethanol, the product was collected to obtain the surface-amino-modified SiO2 nanoparticles.

[0062] (2) Construction of eccentric structure.

[0063] At room temperature (22 °C), PAA and surface-aminated SiO2 nanoparticles were added to water, with PAA concentration of 15 mg / mL and SiO2 nanoparticle concentration of 2500 mg / L. The pH was adjusted to 7.0 with triethylamine, and the mixture was sonicated for 15 min. Isopropanol of 2 times the volume of water was slowly added dropwise to the mixture, and the mixture was stirred at room temperature for 2 hours (335 rpm). Then, isopropanol of 4 times the volume of water was slowly added dropwise to the mixture, and the mixture was stirred at room temperature for 2 hours (535 rpm) to obtain asymmetric SiO2-PAA eccentric particles.

[0064] (3) Preparation of Janus nanomotor.

[0065] Sulfosuccinimidyl-6-(biotinamido)-6-hexanamido hexanoate was dissolved in DMSO, and then dissolved together in PB buffer solution to fix the concentration at 1.1 mg / mL. SiO2-PAA eccentric particles were added to the above solution and shaken overnight at room temperature. The exposed amino group was biotinylated by utilizing the highly active part (NHS ester) in the biotinylation reagent to react with the amino group to form a stable amide bond.

[0066] After removing the PAA layer by washing with water, the surface of the newly exposed nano-SiO2 particles was modified as follows: NHS (9.2072 mg / mL) and EDC (15.336 mg / mL) in a volume ratio of (v:v = 2:1) were rapidly added sequentially to 120 μL of PEG solution (19 mg / mL), and the mixture was shaken overnight at 25 °C. This yielded a Janus-like structure with biotin conjugated on one side and PEG conjugated on the other. Urease PB solution was uniformly mixed with the biotin linker and reacted with shaking at room temperature to obtain biotinylated urease. 2 mg / mL of streptavidin (SA) was dissolved in PB solution (v:v = 1:19). The SA solution was mixed with the PEG-SiO2-Bio solution and reacted with shaking at room temperature. After washing three times with water, the mixture was dissolved in an appropriate amount of PB to obtain PEG-SiO2-Bio-SA. The biotinylated urease solution was added to the PEG-SiO2-Bio-SA solution, shaken overnight at room temperature, and washed three times with PB solution to obtain the silica Janus nanomotor.

[0067] Example 4

[0068] This example provides a Janus nanomotor, which differs from Example 1 in that its nanoparticles are surface-carboxylated Fe3O4 nanoparticles, and its preparation method includes the following steps:

[0069] (1) Preparation of surface carboxylated Fe3O4 nanoparticles.

[0070] Dissolve 8.1 g FeCl·6H2O in 142.5 mL of deionized water and transfer to a three-necked flask. Heat and stir to 70 °C. Weigh 4.4 g FeCl2·4H2O and dissolve in 10 mL of deionized water. Filter the solution, and add 7.5 mL of the solution to the three-necked flask. Under vigorous stirring, rapidly add 18 mL of 25% concentrated ammonia solution. After 1 min, add 4.66 g of oleic acid dropwise. Continue stirring rapidly at 70 °C for 1 h. After the reaction is complete, a black sol-like substance is obtained. The precipitate is separated from the reaction system using an external magnetic field. Wash twice with ethanol to remove excess oleic acid, then wash with deionized water until the solution is neutral. Add 160 mL of 10 mg / mL KMnO4 solution and sonicate in an ultrasonic cleaner for 8 h. After magnetic separation, wash three times with deionized water and then freeze-dry under vacuum to obtain Fe3O4 nanoparticles with carboxyl groups modified on the surface.

[0071] (2) Construction of eccentric structure.

[0072] At room temperature (22 °C), PAA and surface carboxylated Fe3O4 nanoparticles were added to water, with PAA concentration of 3 mg / mL and Fe3O4 nanoparticle concentration of 725 mg / L. The pH was adjusted to 7.0 with NH3·H2O, and the mixture was sonicated for 15 min. Under vigorous magnetic stirring, 2 times the volume of isopropanol was slowly added dropwise to the mixture, and the reaction was carried out at room temperature for 2 hours (335 rpm). Then, 4 times the volume of isopropanol was slowly added dropwise to the mixture, and the reaction was carried out at room temperature for 2 hours (535 rpm) to obtain asymmetric Fe3O4-PAA nanoparticles.

[0073] (3) Preparation of Janus nanomotor.

[0074] Fe3O4-PAA nanoparticles were dispersed in PBS buffer solution, and NHS (9.2072 mg / mL) and EDC (15.336 mg / mL) were added at a volume ratio of (v:v = 2:1). The mixture was shaken at 25 °C for 2 h to activate the carboxyl groups on the Fe3O4 surface. PEG-NH2 was dispersed in PBS buffer solution and added to the Fe3O4-PAA nanoparticle suspension. The mixture was reacted at room temperature for 24 h to allow the PEG-NH2 to couple with the carboxyl groups on the Fe3O4 nanoparticle surface.

[0075] After washing to remove the PAA layer, urease (8000 Da, 2000-fold excess) was coupled. NHS (9.2072 mg / mL) and EDC (15.336 mg / mL) were added rapidly, sequentially, at a volume ratio of (v:v = 2:1) to Fe3O4 solution, and the mixture was shaken at 25°C for 30 min. Then, 100 μL of 20 mg / mL urease solution was added, and the reaction was incubated overnight at 25°C. The product was collected by centrifugation and washed three times with PBS buffer to obtain the Janus nanomotor.

[0076] Comparative Example 1

[0077] This example provides a method for constructing an Au-PAA eccentric structure, and the preparation process is as follows:

[0078] (1) The preparation of gold nanoparticles is the same as step (1) in Example 1.

[0079] (2) The construction of the eccentric structure differs from step (2) of Example 1 only in that the pH is adjusted to 6 or 8 by NH3•H2O respectively.

[0080] Experimental data show that the Au-PAA eccentric structure could not be successfully constructed under the preparation conditions in this example, and the synthesized particles cannot be used to prepare Janus nanomotors.

[0081] Comparative Example 2

[0082] This example provides a method for constructing an Au-PAA eccentric structure, and the preparation process is as follows:

[0083] (1) The preparation of gold nanoparticles is the same as step (1) in Example 1.

[0084] (2) The construction of the eccentric structure differs from step (2) of Example 1 only in that isopropanol with a total volume of 4 times that of water is added.

[0085] Experimental data show that no obvious eccentric structure was observed under the preparation conditions in this example, meaning that the synthesized particles cannot be used for the subsequent preparation of Janus nanomotors.

[0086] The Au-PAA eccentric particles prepared in the examples were characterized, and the results are as follows: Figure 3 As shown, the brightest element is Au, and the element partially surrounded by it is PAA. The Janus nanomotor prepared in the examples was characterized by transmission electron microscopy and elemental analysis, and the results are as follows: Figure 4 As shown, the N element, unique to urease, is distributed on one side of the Au particle.

[0087] In addition, the Janus nanomotor prepared in Example 1 was placed in 0, 1, 5, 10, 15, 20, 25, and 50 mM urea solutions, respectively, and its motion trajectory, mean square displacement change, and diffusion coefficient change were as follows: Figure 5 As shown in the figure, it can be seen that as the urea concentration increases, the motor moving distance gradually increases, the mean square displacement slope and the diffusion coefficient also gradually increase, and it can be effectively driven at a human urea concentration (~10 mM).

[0088] All the raw materials listed in this invention, as well as the upper and lower limits and ranges of the raw materials and the upper and lower limits and ranges of the process parameters (such as temperature, time, etc.), can realize this invention. Examples are not listed one by one here.

[0089] It should be noted that the present invention is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments that have the same structure and perform the same effects as the technical concept within the scope of the present invention are included within the scope of the present invention. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of the present invention, are also included within the scope of the present invention.

Claims

1. A method for preparing Janus nanomotors based on an eccentric structure constructed from polyacrylic acid, characterized in that, Includes the following steps: S1. An eccentric structure was prepared by adjusting the electrostatic adsorption and coordination bonding between spherical nanoparticles and PAA. S2. Based on the eccentric structure, the surface of spherical nanoparticles is asymmetrically modified; Step S1 is as follows: Prepare a reaction solution containing spherical nanoparticles and PAA, adjust the pH to 7.0±0.5 with alkali, so that PAA self-assembles on the surface of spherical nanoparticles, and then add isopropanol to make PAA partially coated on spherical nanoparticles to form an eccentric structure. Step S2 includes the following: S21. Modify the exposed side of the nanoparticles in the eccentric structure with molecules that do not have catalytic function; S22. After removing PAA from the eccentric structure, a catalytic component is then modified on the other side of the nanoparticle to obtain the Janus nanomotor. In step S22, PAA in the eccentric structure is removed by water washing.

2. The method according to claim 1, characterized in that, The alkali is one or more of ammonia, sodium hydroxide, potassium hydroxide, sodium carbonate, sodium bicarbonate, and triethylamine.

3. The method according to claim 1, characterized in that, The spherical nanoparticles include elemental, oxide, or sulfide nanoparticles of gold, silver, palladium, platinum, manganese, iron, cerium, titanium, aluminum, or zinc, inorganic non-metallic nanoparticles, and organic nanoparticles; the nanoparticles are hollow, solid, or porous structures.

4. The method according to claim 1, characterized in that, The diameter of the spherical nanoparticles is 10-500 nm.

5. The method according to claim 1, characterized in that, The component with catalytic function is a biological enzyme.

6. The method according to claim 5, characterized in that, The biological enzymes include urease, catalase, glucose peroxidase, arginase, lipoprotein lipase, lipase, galactosidase, transaminase, decarboxylase, and carbonic anhydrase.

7. A Janus nanomotor, characterized in that, Prepared by the method according to any one of claims 1-6.

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