An electrically driven defective tubular silver micro-nano robot for cargo transportation and its preparation method and application

Abstract

The present invention relates to the field of micro-nano robots, in particular to an electrically driven defective tubular silver micro-nano robot for cargo transportation, and a preparation method and application thereof. The micro-nano robot comprises the following steps: S1, sputtering silver as a conductive layer at a certain inclination angle on the back side of a porous polycarbonate template using a magnetron sputtering method; S2, electrochemically depositing silver in the template pores of the porous polycarbonate template, thereby obtaining a defective tubular silver micro-nano robot in the template pores; S3, polishing and removing the silver conductive layer on the back side of the porous polycarbonate template using aluminum oxide powder; S4, dissolving the porous polycarbonate template using a dichloromethane solution, obtaining a micro-nano robot released into the dichloromethane solution, and collecting the micro-nano robot by centrifugation; S5, performing ultrasonic cleaning and centrifugal collection using anhydrous ethanol and deionized water respectively, to obtain a micro-nano robot dispersed in the aqueous solution. The micro-nano robot has controllable two-dimensional plane and three-dimensional space motion capabilities, thereby realizing controllable transportation of micro-nano scale cargo.

Description

Technical Field

[0001] The present invention relates to the field of micro-nano robots, in particular to an electrically driven defective tubular silver micro-nano robot for cargo transportation, and a preparation method and application thereof. Background Art

[0002] A micro-nano robot is a micro-nano device or apparatus that can convert external energy, such as chemical energy, light energy, ultrasonic energy, thermal energy, and electromagnetic energy, into mechanical energy for its own motion. Depending on the external energy source, micro-nano robots can be driven by chemical, optical, ultrasonic, electrical, and magnetic field-driven methods. Electric micro-nano robots offer many advantages, such as the absence of toxic or hazardous fuels, strong motion performance, flexible and simple control, and good biocompatibility. Therefore, compared to other drive methods, the drive mechanisms and control strategies of electric micro-nano robots have been extensively studied. Furthermore, due to their unique advantage in non-selective cargo transport, electric micro-nano robots have garnered widespread attention for their application in micro-nanoscale cargo transportation. Existing electric micro-nano robots are mostly constructed from two materials with significantly different electrical conductivity, most commonly metal and dielectric materials. Their motion depends on the difference in dielectric constants between the two materials. Therefore, the material significantly influences the motion behavior of existing electric micro-nano robots. Furthermore, the motion behavior of existing electric micro-nano robots is largely dependent on the substrate, making them unable to move autonomously without the substrate.

[0003] However, in the actual application of micro-nano robots, they often face complex three-dimensional network environments. Traditional electric-field-driven micro-nano robots are unable to meet the needs of movement in complex environments, greatly limiting their application in fields such as biomedicine, environmental protection, and micro-nano sensing. Therefore, it is urgent to propose a new type of electric-field-driven micro-nano robot and its preparation method that can overcome the limitations of existing electric-driven micro-nano robots in materials and substrates, achieve flexible and controllable movement behavior in complex three-dimensional network environments, and realize the controlled transportation of micro-nanoscale goods. Summary of the Invention

[0004] The purpose of the present invention is to provide an electrically driven defective tubular silver micro-nano robot for cargo transportation, as well as its preparation method and application. The micro-nano robot has controllable two-dimensional plane and three-dimensional space movement capabilities, thereby realizing the controllable transportation of micro-nano scale cargo.

[0005] The purpose of the present invention is achieved through the following technical solutions:

[0006] A method for preparing an electrically driven defective tubular silver micro-nano robot for cargo transportation comprises the following steps:

[0007] S1, using magnetron sputtering method, sputtering silver as a conductive layer at a certain tilt angle on the back side of the porous polycarbonate template;

[0008] S2, electrochemically depositing silver in the template pores of the porous polycarbonate template, thereby obtaining defective tubular silver micro-nanorobots in the template pores;

[0009] S3, using aluminum oxide powder to polish and remove the silver conductive layer on the back side of the porous polycarbonate template;

[0010] S4, dissolving the porous polycarbonate template using a dichloromethane solution to obtain a micro-nano robot released into the dichloromethane solution, and collecting the micro-nano robot in the dichloromethane solution by centrifugation using a centrifuge;

[0011] S5. Use anhydrous ethanol and deionized water to ultrasonically clean and centrifuge the micro-nano robot to obtain the micro-nano robot dispersed in the aqueous solution.

[0012] Preferably, the porous polycarbonate template has a diameter of 25 mm, a thickness of 15 μm, and a pore diameter of 5 μm.

[0013] Preferably, the sputtering tilt angle in step S1 is 15-20°, and optimally 20°;

[0014] Preferably, the thickness of the sputtered conductive layer in step S1 is 80-100 nanometers, and optimally 100 nanometers.

[0015] Preferably, step S2 specifically adopts a three-electrode system, with the silver layer sputtered on the back side of the template as the working electrode, the platinum wire as the counter electrode, and the silver wire as the reference electrode, and is deposited in a silver deposition solution, so as to obtain a defective tubular silver micro-nano robot in the template hole.

[0016] During the deposition process, the deposition current was set to -4 mA and the deposition time was set to 1000 seconds to obtain a defective tubular silver micro-nano robot with a longitudinally symmetrical structure.

[0017] During the deposition process, the deposition current was set to -8 mA and the deposition time was set to 600 seconds to obtain a defective tubular silver micro-nano robot with a longitudinally asymmetric structure.

[0018] Preferably, the silver deposit solution is prepared from silver nitrate, boric acid, and dilute nitric acid. The specific process flow of the preparation is as follows: slowly adding the boric acid solution dropwise to the silver nitrate solution, stirring for 10 minutes using a mechanical stirrer, adding the dilute nitric acid solution dropwise to the resulting solution, and adjusting the pH of the solution to 1.5 to obtain the silver deposit solution.

[0019] A cargo transport electrically driven defective tubular silver micro-nano robot is prepared using a cargo transport electrically driven defective tubular silver micro-nano robot preparation method.

[0020] The application of the electrically driven defective tubular silver micro-nano robot for cargo transportation in the controllable transportation of cargo at the micro-nano scale.

[0021] The beneficial effects of the present invention are:

[0022] The single metal material defect tubular silver micro-nano robot prepared by combining magnetron sputtering and electrochemical deposition has an asymmetric structure, can respond to the stimulation of an external electric field and exhibit motion behavior; the materials for preparing the defect tubular micro-nano robot using the proposed preparation method include but are not limited to silver, and other metal conductive materials can also be used for preparation, overcoming the limitations of the material composition of traditional electric field-driven micro-nano robots, and the range of preparation materials available is wide; the prepared defect tubular silver micro-nano robot relies on an asymmetric structure to move, can overcome the limitations of the substrate and realize three-dimensional spatial motion behavior; the proposed micro-nano robot can realize controllable attraction, loading, transportation and release of cargo, and the cargo includes but is not limited to inert particles, polymer drugs, and biological cells; because the micro-nano robot is composed of nanosilver particles, it can release metal silver ions during movement and cargo transportation, which has a strong killing effect on microorganisms such as bacteria and viruses, and has broad application prospects in the fields of biomedicine and environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the fabrication process of defective tubular silver micro-nanorobots;

[0024] Figure 2 This is a scanning electron microscope image of a defective tubular silver micro-nanorobot with a longitudinally symmetrical structure;

[0025] Figure 3 This is a scanning electron microscope image of a defective tubular silver micro-nanorobot with a longitudinally asymmetric structure;

[0026] Figure 4 This is a diagram showing the composition of the electric field driven micro-nano robot drive control device;

[0027] Figure 5 This is a diagram showing the driving and control experiment of a defective tubular silver micro-nano robot with a longitudinally symmetrical structure;

[0028] Figure 6 This is a diagram of the three-dimensional motion experiment of a defective tubular silver micro-nano robot with a longitudinally asymmetric structure;

[0029] Figure 7 Schematic diagram and experimental diagram of cargo transportation by electrically driven defective tubular silver micro-nanorobot.

[0030] In the picture:

[0031] 1-Microscope; 2-Borosilicate glass slide; 3-Indium tin oxide coating; 4-Polyimide patch; 5-Silicon dioxide coating; 6-Wire. DETAILED DESCRIPTION

[0032] like Figure 1-3 As shown, a method for preparing an electrically driven defective tubular silver micro-nano robot for cargo transportation is described in detail:

[0033] Example 1:

[0034] A method for preparing an electrically driven defective tubular silver micro-nano robot for cargo transportation comprises the following steps:

[0035] S1. Using a magnetron sputtering method, silver is sputtered at a certain tilt angle on the back side of a porous polycarbonate template as a conductive layer; wherein the porous polycarbonate template has a diameter of 25 mm, a thickness of 15 μm, and a pore diameter of 5 μm; the sputtering tilt angle is 20°; and the thickness of the sputtered conductive layer is 100 nm.

[0036] S2. Electrochemically depositing silver in the template pores of the porous polycarbonate template, thereby obtaining a defective tubular metallic silver robot in the template pores; specifically, a three-electrode system is used, wherein a silver layer sputtered on the back side of the template serves as a working electrode, a platinum wire serves as a counter electrode, and a silver wire serves as a reference electrode, and deposition is performed in a silver deposition solution, thereby obtaining a defective tubular silver micro-nano robot in the template pores;

[0037] During the deposition process, the deposition current was set to -4 mA and the deposition time was set to 1000 seconds to obtain a defective tubular silver micro-nano robot with a longitudinally symmetrical structure.

[0038] During the deposition process, the deposition current was set to -8 mA and the deposition time was set to 600 seconds to obtain a defective tubular silver micro-nano robot with a longitudinally asymmetric structure.

[0039] The silver deposition solution is prepared from silver nitrate, boric acid, and dilute nitric acid. The specific process flow of the preparation is as follows: 10 mL of a 0.1 mol / L boric acid solution is slowly added dropwise to 10 mL of a 0.2 mol / L silver nitrate solution, and the mixture is stirred for 10 minutes using a mechanical stirrer. A 6 mol / L dilute nitric acid solution is then added dropwise to the resulting solution, and the pH of the solution is adjusted to 1.5 to obtain the silver deposition solution.

[0040] S3, using aluminum oxide powder to polish and remove the silver conductive layer on the back side of the porous polycarbonate template;

[0041] S4, dissolving the porous polycarbonate template using a dichloromethane solution to obtain a micro-nano robot released into the dichloromethane solution, and collecting the micro-nano robot in the dichloromethane solution by centrifugation using a centrifuge;

[0042] S5. Use anhydrous ethanol and deionized water to ultrasonically clean and centrifuge the micro-nano robot to obtain the micro-nano robot dispersed in the aqueous solution.

[0043] Example 2:

[0044] A method for preparing an electrically driven defective tubular silver micro-nano robot for cargo transportation comprises the following steps:

[0045] S1. Using a magnetron sputtering method, silver is sputtered at a certain tilt angle on the back side of a porous polycarbonate template as a conductive layer; wherein the porous polycarbonate template has a diameter of 25 mm, a thickness of 15 μm, and a pore diameter of 5 μm; the sputtering tilt angle is 18°; and the thickness of the sputtered conductive layer is 90 nm.

[0046] S2. Electrochemically depositing silver in the template pores of the porous polycarbonate template, thereby obtaining a defective tubular metallic silver robot in the template pores; specifically, a three-electrode system is used, wherein a silver layer sputtered on the back side of the template serves as a working electrode, a platinum wire serves as a counter electrode, and a silver wire serves as a reference electrode, and deposition is performed in a silver deposition solution, thereby obtaining a defective tubular silver micro-nano robot in the template pores;

[0047] During the deposition process, the deposition current was set to -4 mA and the deposition time was set to 1000 seconds to obtain a defective tubular silver micro-nano robot with a longitudinally symmetrical structure.

[0048] During the deposition process, the deposition current was set to -8 mA and the deposition time was set to 600 seconds to obtain a defective tubular silver micro-nano robot with a longitudinally asymmetric structure.

[0049] The silver deposition solution is prepared from silver nitrate, boric acid, and dilute nitric acid. The specific process flow of the preparation is as follows: 10 mL of a 0.1 mol / L boric acid solution is slowly added dropwise to 10 mL of a 0.2 mol / L silver nitrate solution, and the mixture is stirred for 10 minutes using a mechanical stirrer. A 6 mol / L dilute nitric acid solution is then added dropwise to the resulting solution, and the pH of the solution is adjusted to 1.5 to obtain the silver deposition solution.

[0050] S3, using aluminum oxide powder to polish and remove the silver conductive layer on the back side of the porous polycarbonate template;

[0051] S4, dissolving the porous polycarbonate template using a dichloromethane solution to obtain a micro-nano robot released into the dichloromethane solution, and collecting the micro-nano robot in the dichloromethane solution by centrifugation using a centrifuge;

[0052] S5. Use anhydrous ethanol and deionized water to ultrasonically clean and centrifuge the micro-nano robot to obtain the micro-nano robot dispersed in the aqueous solution.

[0053] Example 3:

[0054] A method for preparing an electrically driven defective tubular silver micro-nano robot for cargo transportation comprises the following steps:

[0055] S1. Using a magnetron sputtering method, silver is sputtered at a certain tilt angle on the back side of a porous polycarbonate template as a conductive layer; wherein the porous polycarbonate template has a diameter of 25 mm, a thickness of 15 μm, and a pore diameter of 5 μm; the sputtering tilt angle is 15°; and the thickness of the sputtered conductive layer is 80 nm.

[0056] S2. Electrochemically depositing silver in the template pores of the porous polycarbonate template, thereby obtaining a defective tubular metallic silver robot in the template pores; specifically, a three-electrode system is used, wherein a silver layer sputtered on the back side of the template serves as a working electrode, a platinum wire serves as a counter electrode, and a silver wire serves as a reference electrode, and deposition is performed in a silver deposition solution, thereby obtaining a defective tubular silver micro-nano robot in the template pores;

[0057] During the deposition process, the deposition current was set to -4 mA and the deposition time was set to 1000 seconds to obtain a defective tubular silver micro-nano robot with a longitudinally symmetrical structure.

[0058] During the deposition process, the deposition current was set to -8 mA and the deposition time was set to 600 seconds to obtain a defective tubular silver micro-nano robot with a longitudinally asymmetric structure.

[0059] The silver deposition solution is prepared from silver nitrate, boric acid, and dilute nitric acid. The specific process flow of the preparation is as follows: 10 mL of a 0.1 mol / L boric acid solution is slowly added dropwise to 10 mL of a 0.2 mol / L silver nitrate solution, and the mixture is stirred for 10 minutes using a mechanical stirrer. A 6 mol / L dilute nitric acid solution is then added dropwise to the resulting solution, and the pH of the solution is adjusted to 1.5 to obtain the silver deposition solution.

[0060] S3, using aluminum oxide powder to polish and remove the silver conductive layer on the back side of the porous polycarbonate template;

[0061] S4, dissolving the porous polycarbonate template using a dichloromethane solution to obtain a micro-nano robot released into the dichloromethane solution, and collecting the micro-nano robot in the dichloromethane solution by centrifugation using a centrifuge;

[0062] S5. Use anhydrous ethanol and deionized water to ultrasonically clean and centrifuge the micro-nano robot to obtain the micro-nano robot dispersed in the aqueous solution.

[0063] In the above examples 1 to 3, due to the tilt angle during the sputtering of the conductive layer by the magnetron sputtering method, the conductive silver layer is asymmetrically distributed in the template holes and forms a pointed tip, resulting in uneven distribution of charge in the template holes during the electrodeposition process, ultimately leading to the formation of defective structures in the silver micro-nano robot. During the deposition process, the deposition current was set to -4 mA and the deposition time was set to 1000 seconds, resulting in a defective tubular silver micro-nano robot with a longitudinally symmetrical structure, as shown in FIG. Figure 2 During the deposition process, the deposition current was set to -8 mA and the deposition time was set to 600 seconds, and a defective tubular silver micro-nano robot with a longitudinal asymmetric structure was obtained, as shown in FIG. Figure 3 By controlling the electrochemical deposition current and time, it is possible to produce both longitudinally symmetrical and longitudinally asymmetric defective tubular silver micro-nanorobots. The measured micro-nanorobots have an average length of 7 microns, an average diameter of 5 microns, and an average wall thickness of 100 nanometers.

[0064] Furthermore, a driving control device for an electrically driven defective tubular silver micro-nano robot for cargo transportation is described in detail:

[0065] A drive control device for an electrically driven defective tubular silver micro-nano robot for cargo transportation mainly consists of two parts: a microscope and an electric field generator. The electric field generator is composed of borosilicate glass coated with indium tin oxide and silicon dioxide, a polyimide patch, and a wire. Figure 4 As shown in the figure, an 80μm-thick polyimide patch with a 3mm-diameter cylindrical hole serves as the experimental area for the micro-nano robot. The surface of the borosilicate glass is first coated with a 180nm-thick indium tin oxide (ITO) layer, which acts as a conductive layer to generate an electric field. A second, 200nm-thick silicon dioxide layer acts as an isolation layer to prevent adhesion between the micro-nano robot and the conductive layer. A 20kHz, 10V sinusoidal signal is generated by a signal generator. After being amplified twice by a power amplifier, it is input into the ITO coating of the borosilicate glass as a signal source, generating a spatial AC electric field within the experimental area.

[0066] Furthermore, because the micro-nano robot is made of a single metal material, silver, it undergoes polarization under the action of an external AC electric field. At the same time, because the micro-nano robot itself has an asymmetric structure, it can respond to the stimulation of the external electric field and exhibit motion behavior:

[0067] like Figure 5As shown in the figure, the planar motion drive control of the defective tubular silver micro-nano robot with a longitudinally symmetrical structure includes three steps. First, when there is no external electric field, the micro-nano robot is in a horizontally fallen state in the solution. Secondly, the 20kHz, 10V spatial AC electric field is turned on, and the micro-nano robot quickly switches from a horizontally fallen state to a vertically standing state within 1 second. The micro-nano robot exhibits clockwise motion behavior in the horizontal plane. Finally, the AC electric field frequency is increased from 20kHz to 200kHz, and the motion direction of the micro-nano robot changes, exhibiting counterclockwise motion behavior in the horizontal plane. By controlling the frequency of the applied sinusoidal signal, the planar motion direction switching control of the defective tubular silver micro-nano robot with a longitudinally symmetrical structure can be achieved.

[0068] like Figure 6 As shown in the figure, the three-dimensional spatial driving control of the defective tubular silver micro-nano robot with a longitudinal asymmetric structure also includes three steps. First, when there is no external electric field, the micro-nano robot is stationary in the solution and is in a horizontally fallen state. Secondly, a 200kHz, 10V spatial AC electric field is applied, and the micro-nano robot exhibits counterclockwise motion in the plane. Finally, the AC electric field frequency is reduced from 200kHz to 20kHz. Due to its longitudinal asymmetric structure, the micro-nano robot generates asymmetric electroosmosis in the longitudinal direction and exhibits three-dimensional spatial clockwise motion, which is specifically manifested as the defocusing phenomenon of the micro-nano robot in microscopic observation. By controlling the frequency of the applied sinusoidal wave signal, the defective tubular silver micro-nano robot with a longitudinal asymmetric structure can achieve three-dimensional spatial motion and control its motion direction.

[0069] Furthermore, the electrically driven defective tubular silver micro-nano robot proposed in the present invention can realize the controllable attraction, loading, transportation and release of goods:

[0070] like Figure 7Figure 2 illustrates the cargo transport process of an electrically driven defective tubular silver microrobot. First, without an external electric field, the microrobot remains stationary in a horizontally folded position within the solution. Second, a 20kHz, 10V AC electric field is applied, causing the microrobot to switch from its horizontally folded state to a vertically upright motion state. By controlling the frequency of the applied AC electric field, the microrobot's motion direction can be controlled, allowing it to approach the desired cargo. Third, when the microrobot is sufficiently close to the desired cargo, the applied AC electric field frequency is adjusted to 200kHz, creating an electric field intensity gradient around the microrobot. This electric field intensity gradient causes the cargo to be attracted to the microrobot by dielectric forces, allowing the microrobot to carry the cargo horizontally, achieving cargo transport. Finally, when the microrobot reaches the desired location with the cargo, the AC electric field frequency is reduced from 200kHz to 20kHz. Electroosmotic flow causes the cargo to be displaced by the microrobot, achieving cargo release.

[0071] Experiments using inert particles with a diameter of 2 μm as cargo demonstrated the feasibility of the proposed electrically driven defective tubular silver micro-nanorobot for cargo transport. Furthermore, due to the electrically driven micro-nanorobot's excellent biocompatibility and non-selective cargo transport capabilities, potential cargoes include, but are not limited to, inert particles, polymer drugs, and biological cells.

[0072] At the same time, since the micro-nano robots are made of nanosilver particles, they can release metallic silver ions during movement and cargo transportation, which have a strong killing effect on microorganisms such as bacteria and viruses, and have broad application prospects in biomedicine, environmental protection and other fields.

[0073] At the same time, the magnetron sputtering method can be used to sputter magnetic materials such as iron, cobalt, and nickel on the surface of the micro-nano robot, and apply a magnetic field to further improve the controllability of the micro-nano robot's cargo transportation.

[0074] The basic principles of the present invention are:

[0075] An electrically driven defective tubular silver micro-nanorobot for cargo transport is constructed from a single metal, silver. The robot is fabricated using a combination of magnetron sputtering and electrochemical deposition, a four-step process. By controlling the electrochemical deposition current and time, it is possible to produce either a longitudinally symmetrical or asymmetric defective tubular silver micro-nanorobot.

[0076] A drive control device for an electrically driven, defective tubular silver micro-nano robot for cargo transport primarily consists of a microscope and an electric field generator. The electric field generator is constructed from borosilicate glass coated with indium tin oxide and silicon dioxide, polyimide patches, and wires. The coated borosilicate glass serves as an electrode to generate the electric field. A signal generator generates a sinusoidal signal, which is amplified by a power amplifier and then input into the indium tin oxide coating of the borosilicate glass as a signal source. This ultimately creates a spatial AC electric field in the area between the two glass sheets. The polyimide patches serve as the experimental area for the micro-nano robot. The robot's motion behavior is observed using a microscope.

[0077] Under the influence of an external AC electric field, the defective tubular silver microrobot, with its longitudinally symmetrical structure, exhibits structural asymmetry in the horizontal plane, enabling it to achieve horizontal motion within the plane. By varying the amplitude and frequency of the input electrical signal, the speed and direction of the microrobot's motion can be controlled. Because the defective tubular silver microrobot exhibits structural asymmetry both horizontally and vertically, it can achieve three-dimensional motion in space under the influence of an AC electric field.

[0078] Under a high-frequency AC electric field, an electric field intensity gradient is generated in the local area surrounding the defective tubular micro-nanorobot. This electric field intensity gradient acts as a force on cargo surrounding the micro-nanorobot, attracting it and loading it. Under a low-frequency AC electric field, an electroosmotic flow is generated in the local area surrounding the defective tubular micro-nanorobot. Under the influence of this electroosmotic flow, cargo carried by the micro-nanorobot is released under the propulsion of the fluid. Furthermore, because the proposed electric-field-driven defective tubular micro-nanorobot possesses autonomous motion, controlled attraction, loading, transport, and release of cargo can be achieved by varying the frequency of the applied AC electric field. The micro-nanorobot is non-selective for the cargo it transports, including but not limited to inert particles, polymer drugs, and biological cells. The proposed micro-nanorobot has broad application prospects in fields such as biomedicine.

Claims

1. A method for preparing an electrically driven defective tubular silver micro-nano robot for cargo transportation, characterized by: The following steps are involved: S1, using magnetron sputtering method, sputtering silver as a conductive layer at a certain tilt angle on the back side of the porous polycarbonate template; S2, electrochemically depositing silver in the template pores of the porous polycarbonate template, thereby obtaining defective tubular silver micro-nanorobots in the template pores; S3, using aluminum oxide powder to polish and remove the silver conductive layer on the back side of the porous polycarbonate template; S4, using a dichloromethane solution to dissolve the porous polycarbonate template to obtain a micro-nano robot released into the dichloromethane solution, and using a centrifuge to collect the micro-nano robot in the dichloromethane solution; S5. Ultrasonic cleaning and centrifugal collection of the micro-nano robot using anhydrous ethanol and deionized water to obtain the micro-nano robot dispersed in the aqueous solution; In step S1, the sputtering tilt angle is 15-20°; The step S2 specifically adopts a three-electrode system, with the silver layer sputtered on the back side of the template as the working electrode, the platinum wire as the counter electrode, and the silver wire as the reference electrode, and deposits them in the silver deposition solution, that is, obtaining a defective tubular silver micro-nano robot in the template hole.

2. The preparation method according to claim 1, wherein: The porous polycarbonate template has a diameter of 25 mm, a thickness of 15 μm, and a pore diameter of 5 μm.

3. The preparation method according to claim 1, wherein: The thickness of the sputtered conductive layer in step S1 is 80-100 nanometers.

4. The preparation method according to claim 1, characterized in that: During the deposition process, the deposition current was set to -4 mA and the deposition time was set to 1000 seconds to obtain a defective tubular silver micro-nano robot with a longitudinally symmetrical structure.

5. The preparation method according to claim 1, characterized in that: During the deposition process, the deposition current was set to -8 mA and the deposition time was set to 600 seconds to obtain a defective tubular silver micro-nano robot with a longitudinally asymmetric structure.

6. The preparation method according to claim 1, characterized in that: The silver deposition solution is prepared from silver nitrate, boric acid, and dilute nitric acid. The specific process flow of the preparation is as follows: slowly adding the boric acid solution dropwise to the silver nitrate solution, stirring for 10 minutes using a mechanical stirrer, and then adding the dilute nitric acid solution dropwise to the resulting solution, and adjusting the pH of the solution to 1.5 to obtain the silver deposition solution.

7. An electrically driven defective tubular silver micro-nano robot for cargo transportation, prepared using the preparation method described in any one of claims 1 to 6.

8. Application of the electrically driven defective tubular silver micro-nano robot for cargo transportation according to claim 7 in controllable transportation of cargo at the micro-nano scale.

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