Non-contact micro-robot for carrying and carrying objects, and preparation method and application thereof

Abstract

This invention discloses a non-contact microrobot for transporting goods, its fabrication method, and its applications, belonging to the field of microrobot technology. The non-contact microrobot for transporting goods provided by this invention includes a first arm and a second arm connected in a V-shape; both the first and second arms are composed of a polymer layer, a first titanium layer, a magnetic layer, and a second titanium layer stacked together. The microrobot provided by this invention can effectively increase the number of goods transported in a single operation, as well as the accuracy of the transport position of each goods. This invention also provides a fabrication method and applications for the aforementioned microrobot.

Description

Technical Field

[0001] This invention relates to the field of microrobot technology, and in particular to a non-contact microrobot for transporting goods, its manufacturing method, and its application. Background Technology

[0002] As a future means of biomedical application, microrobot transportation has broad application prospects. Currently, magnetic fields, electric fields, sound fields, and light fields are used to drive microrobots. Magnetic fields, as an external driving field with strong penetrability and high biosafety, are widely used to drive magnetic microrobots.

[0003] Miniature robots capable of transporting objects without contact have potential implications for future precision medicine. Unlike direct contact transportation, non-contact transportation ensures the safety of transported objects. For example, fragile materials such as cells, proteins, and microorganisms can maintain their biological activity during transportation using non-contact transportation.

[0004] Currently, there is very little research on using microrobots to transport objects. Some relevant research is listed below: There are technologies that use a cylindrical microrobot to capture and transport individual microspheres in polyethylene glycol; there are also technologies that use nanowires to transport and place individual polystyrene microspheres; and there are technologies that use spherical microrobots to transport individual polystyrene beads.

[0005] In other words, traditional technologies have only focused on transporting single cargo in their research, without addressing the simultaneous transport of multiple cargoes, and the accuracy of cargo transport needs to be improved. Summary of the Invention

[0006] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention proposes a non-contact microrobot for transporting goods, which can effectively increase the number of goods transported in a single operation and the accuracy of the transport position of each goods.

[0007] The present invention also provides a method for preparing the above-mentioned microrobot.

[0008] This invention also provides applications of the aforementioned microrobot.

[0009] According to an embodiment of a first aspect of the present invention, a non-contact microrobot for transporting goods is provided, the microrobot comprising a first arm and a second arm connected in a V-shape; and both the first arm and the second arm are composed of a polymer layer, a first titanium layer, a magnetic layer and a second titanium layer stacked together.

[0010] The microrobot according to embodiments of the present invention has at least the following beneficial effects:

[0011] Compared with traditional linear or unstructured microrobots, the microrobot provided by this invention has a special structure. After being magnetized, it generates different numbers and positions of vortices in a rotating magnetic field (specifically, at least one vortex can be generated on each side of the microrobot's body). Therefore, it can transport multiple objects simultaneously.

[0012] The microrobot provided by this invention utilizes the high bonding strength between the first titanium layer, the polymer layer, and the magnetic layer, thereby improving the service life of the obtained microrobot and simplifying the preparation process; it also utilizes the high biocompatibility of the second titanium layer, broadening the application prospects of the obtained microrobot in the biomedical field; and it utilizes the magnetism of the magnetic layer, providing a basis for its rotation and transportation in a magnetic field.

[0013] According to some embodiments of the present invention, the included angle between the first arm and the second arm is 100 to 135°. For example, it may be about 110°, 120° or about 130°.

[0014] According to some embodiments of the present invention, the lengths of the first arm and the second arm are each independently selected from any value between 40 and 60 μm.

[0015] The lengths of the first arm and the second arm may be equal or unequal.

[0016] For example, the length of both the first and second arms is approximately 50 μm.

[0017] According to some embodiments of the present invention, the widths of the first arm and the second arm are independently selected from any value between 20 and 30 μm. Specifically, for example, the widths of the first arm and the second arm are equal and both are approximately 20 μm.

[0018] According to some embodiments of the present invention, the thickness of the microrobot is 5 to 7.5 μm. For example, it can be about 5 μm, 5.5 μm, or about 6 μm.

[0019] According to some embodiments of the present invention, the polymer layer is made of photoresist. Specifically, the photoresist includes at least one of SU-8 2005, AZ4330, and AZ 12XT-20PL-5.

[0020] According to some embodiments of the present invention, the magnetic layer is made of at least one of cobalt and nickel. Both of these materials have good ferromagnetism; cobalt has better ferromagnetism, therefore cobalt is preferred as the magnetic layer in actual production.

[0021] According to some embodiments of the present invention, the thickness ratio of the polymer layer to the first titanium layer is 1 μm: 2.5 to 3.5 nm. For example, it can be approximately 1 μm: 3 nm.

[0022] According to some embodiments of the present invention, the thickness ratio of the polymer layer to the magnetic layer is 1 μm: 50–70 nm. For example, it can be approximately 1 μm: 60 nm.

[0023] According to some embodiments of the present invention, the thickness ratio of the polymer layer to the second titanium layer is 1 μm: 2.5 to 3.5 nm. For example, it can be approximately 1 μm: 3 nm.

[0024] According to some embodiments of the present invention, the microrobot is a long-armed magnetized microrobot, and the magnetization direction of the long-armed magnetized microrobot is parallel to the first arm or the second arm.

[0025] According to some embodiments of the present invention, the microrobot is a short-axis magnetized microrobot, and the magnetization direction of the short-axis magnetized microrobot coincides with the direction of the bisector of the angle between the first arm and the second arm.

[0026] According to an embodiment of a second aspect of the present invention, a method for fabricating the microrobot is provided, the method comprising:

[0027] Provide a polymer core with a V-shaped structure;

[0028] The first titanium layer, the cobalt layer, and the second titanium layer are sequentially sputtered onto the polymer core to form the first and second arms connected in a V-shape.

[0029] Since the preparation method adopts all the technical solutions of the microrobots in the above embodiments, it has at least all the beneficial effects brought about by the technical solutions in the above embodiments. Furthermore, the preparation method provided by the present invention is simple to operate and easy to implement. Furthermore, the V-shaped core determines the length, width, and included angle of the first and second arms of the obtained microrobot; the superimposed thickness of the polymer layer, the first titanium layer, the magnetic layer, and the second titanium layer is the wall thickness of the first or second arm.

[0030] According to some embodiments of the present invention, the preparation method further includes sequentially demagnetizing and magnetizing the obtained microrobot.

[0031] The demagnetization reduces the disordered magnetic domains inherent in the magnetic layer; the magnetization produces magnetism of a specific direction and intensity.

[0032] According to some embodiments of the present invention, the demagnetizing intensity is 1 to 1.5 T.

[0033] According to some embodiments of the present invention, the magnetization intensity is 1.5 to 2T.

[0034] According to some embodiments of the present invention, the demagnetization and magnetization are performed using a magnetizer. Unless otherwise specified, the intensity of demagnetization and magnetization refers to the magnetic field intensity during the corresponding operation.

[0035] According to an embodiment of a third aspect of the present invention, a method for non-contact transport of a load using the microrobot is provided, the method comprising the microrobot rotating under the action of a rotating magnetic field, causing the surrounding fluid to generate vortices; the load being captured by the vortex and transported to a designated location by the movement of the microrobot.

[0036] Since the method employs all the technical solutions of the microrobots described in the above embodiments, it possesses at least all the beneficial effects brought about by the technical solutions of the above embodiments.

[0037] According to some embodiments of the present invention, the carrier includes at least one of a sphere and an irregular shape.

[0038] According to some embodiments of the present invention, during the transportation process, the load experiences an upward viscous resistance on the order of 10. -8 N.

[0039] According to some embodiments of the present invention, during the transportation process, the difference between the gravity and buoyancy experienced by the cargo is on the order of 10. -13 N.

[0040] Since the viscous drag is much greater than the difference between gravity and buoyancy, the load will be captured and carried by the vortex generated by the microrobot.

[0041] According to some embodiments of the present invention, the viscous resistance F drag ≈6πμR(UV);

[0042] Where μ represents the dynamic viscosity of the fluid, in mPa·s;

[0043] R represents the radius of the object, in μm;

[0044] U represents the velocity of the fluid, measured in μm / s;

[0045] V represents the velocity of the object, measured in μm / s.

[0046] In actual calculations, the units of the above parameters can be increased or decreased by the same factor based on common sense.

[0047] According to some embodiments of the present invention, the fluid comprises at least one of a methylcellulose solution and a bodily fluid. When the fluid is selected from the methylcellulose solution, the concentration of the methylcellulose solution is 0.3 to 0.5% w / v; more specifically, it may be about 0.4% w / v. When the fluid is selected from the bodily fluid, the bodily fluid comprises at least one of whole blood, cerebrospinal fluid, and synovial fluid.

[0048] According to some embodiments of the present invention, the radius of the carrier is an equivalent radius. That is, when the carrier is irregularly shaped, its radius is the radius of a sphere of equal volume.

[0049] According to some embodiments of the present invention, the carrier includes at least one of polystyrene microspheres, cells, microorganisms, and protein crystals.

[0050] According to some embodiments of the present invention, the rotation frequency of the microrobot is 3 to 8 Hz. Specifically, it can be approximately 4 Hz, 5 Hz, 6 Hz, or approximately 7 Hz. Unless otherwise specified, the rotation frequency of the microrobot is the same as the rotation frequency of the rotating magnetic field.

[0051] According to some embodiments of the present invention, the field strength of the rotating magnetic field is 3 to 8 mT. For example, it can be approximately 5 mT.

[0052] In actual use, the transport speed of the cargo and the maximum number of cargoes that can be transported at one time can be adjusted by adjusting the parameters of the external magnetic field, the rotation frequency of the microrobot, the fluid parameters, and the cargo parameters.

[0053] According to some embodiments of the present invention, the microrobot can carry a maximum of 2 items in a single operation. For example, it can carry 3 or 4 items.

[0054] According to some embodiments of the present invention, the microrobot carries the load with precise positioning. Specifically, the distance deviation between the designed position and the actual position reached is ≤20μm.

[0055] When the microrobot is used for fixed-point transportation, its rotation frequency differs during the transport process with the load, after the load is released, and during the departure process. This avoids vortices generated during departure affecting the position of the released load. More specifically, during departure, the microrobot's rotation frequency is ≤0.5Hz.

[0056] Unless otherwise specified, the term "about" in this invention actually means that the error is allowed to be within ±2%, for example, about 100 is actually 100 ± 2% × 100.

[0057] Unless otherwise specified, "between" in this invention includes the number itself, for example, "between 2 and 3" includes the endpoint values ​​2 and 3.

[0058] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. Attached Figure Description

[0059] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0060] Figure 1 This is a schematic diagram of the polymer layer in the microrobot obtained in Embodiment 1 of the present invention.

[0061] Figure 2 This is a schematic diagram of the non-contact transport process of the microrobot obtained in Embodiments 1-2 of the present invention.

[0062] Figure 3 This is a simulation diagram of the microrobot rolling forward obtained in Embodiments 1-2 of the present invention.

[0063] Figure 4 This is a schematic diagram of the microrobot obtained in Embodiment 1 of the present invention carrying a load at different frequencies.

[0064] Figure 5 This is a schematic diagram showing the number of objects carried by the microrobot obtained in Embodiment 1 of the present invention.

[0065] Figure 6 This is a schematic diagram showing the speed of the loads when the microrobot obtained in Embodiment 1 of the present invention carries multiple loads.

[0066] Figure 7 This is a diagram illustrating the effect of the microrobot obtained in Embodiment 1 of the present invention on the fixed-point transportation and arrangement of the load.

[0067] Figure 8 This is a comparison of the interlayer binding energy results of the microrobot obtained in Embodiment 1 and Comparative Example 1 of the present invention.

[0068] Figure 9 These are the magnetic domain arrangements and directional arrangements under static magnetic fields observed by the microrobots obtained in Embodiments 1-2 of this invention under AFM.

[0069] Figure 10 This is a schematic diagram of the loads carried by the microrobot obtained in Embodiment 2 of the present invention when carrying multiple loads. Detailed Implementation

[0070] The following will describe the concept and technical effects of the present invention clearly and completely with reference to embodiments, so as to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention.

[0071] In the description of this invention, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0072] Unless otherwise specified, the polystyrene microspheres used in the specific embodiments were purchased from Shanghai Dibai Biotechnology Co., Ltd.

[0073] Example 1

[0074] This example demonstrates the fabrication of a microrobot, with the specific steps as follows:

[0075] S1. Reference Figure 1 The core was coated with SU-8 2005 photoresist (purchased from Nantong Zhongxin Qiheng Energy Technology Co., Ltd.) and exposed to ultraviolet light using a photomask exposure machine to obtain a polymer layer with a thickness of 5μm as the core; the core is V-shaped.

[0076] S2. Using a multi-source integrated PVD equipment, a first titanium layer with a thickness of 15 nm, a magnetic layer made of cobalt with a thickness of 300 nm, and a second titanium layer with a thickness of 15 nm are sequentially sputtered onto the surface of the polymer layer obtained in step S1.

[0077] S3. The component obtained in step S2 is demagnetized and magnetized in sequence. The demagnetization intensity is 1T and the magnetization intensity is 2T. The magnetization direction is parallel to the first arm or the second arm.

[0078] The microrobot obtained in this example is a long-armed magnetized microrobot. It is V-shaped and consists of a connected first arm and a second arm; the length (50 μm) and width (20 μm) of the first and second arms are determined by… Figure 1 The thickness of the arm is determined by the stacked thickness of the polymer layer, the first titanium layer, the magnetic layer, and the second titanium layer, as shown in the core diagram.

[0079] Example 2

[0080] This example demonstrates the fabrication of a microrobot, which differs from Example 1 in that:

[0081] In step S3, the magnetization direction coincides with the angle bisectors of the first and second arms.

[0082] Comparative Example 1

[0083] This example demonstrates the fabrication of a microrobot, which differs from Example 1 in that:

[0084] Step S2 does not include the setting of the first titanium layer.

[0085] Test Example 1

[0086] This example tests the magnetic domain arrangement and directional alignment of the microrobots obtained in Examples 1 and 2 in a static magnetic field. Specific test conditions were as follows: a static magnetic field of 6.8 mT was applied in both the X and Y directions; the fluid environment in which the microrobots were present was a 0.4% w / v methylcellulose solution. The test method involved AFM sample preparation, with the microrobot array cut from a 3-inch silicon wafer into 1cm × 1cm square wafers. The magnetic domains of the microrobots were observed using the magnetic field module (MFM) of an atomic force microscope. The test results showed that the magnetization directions of the long-arm magnetized and short-axis magnetized microrobots were aligned with the X and Y directions of the magnetic field, respectively. This indicates that the magnetization directions of the microrobots obtained in Examples 1 and 2 of this invention are the same as their design directions. Specific test results are as follows: Figure 9 As shown.

[0087] Test Example 2

[0088] This example tests the feasibility of the microrobots obtained in Examples 1 and 2 for carrying loads. Specifically:

[0089] In its original state, the cargo is placed at the bottom of a container containing fluid;

[0090] A rotating magnetic field causes a microrobot to rotate in a fluid, creating vortices in the surrounding fluid; observe whether the load will be captured by the vortex.

[0091] In this example, the fluid is a 0.4% w / v methylcellulose solution with a density of 1020 kg / m³. 3 The container is made of PDMS. Specifically, the container has an outer dimension of 1.5cm × 1.5cm × 0.2cm (cubic prism) and an inner dimension of 0.7cm in diameter and 0.2cm in height (cylinder).

[0092] The substrate consists of polystyrene microspheres with a diameter of 20 μm; the density of the polystyrene microspheres is 1040 kg / m³. 3 .

[0093] The microrobot rotates at a frequency of 3 Hz and has a magnetic field strength of 8 mT.

[0094] The results showed that both the long-armed and short-axis magnetized microrobots could capture and transport the corresponding polystyrene microspheres; the fluid vortices generated by the long-armed magnetized microrobots were located on both sides of their bodies, while the vortices generated by the short-axis magnetized microrobots were located at the end of their long arms. A schematic diagram of the specific process is shown below. Figure 2 As shown; the red arrow in the figure indicates the direction of magnetization.

[0095] This example also uses policy simulation to explain the mechanism of the aforementioned transport; specifically:

[0096] At a rotational frequency of 3 Hz, the microrobots obtained in Examples 1 and 2 were all able to generate vortices. The F of polystyrene microspheres in viscous fluids... g -F b 8×10 -13 N, where F g The calculated value of the gravitational force acting on the polystyrene microspheres is 4.34 × 10⁻⁶. -11 N;F b The buoyancy force acting on the polystyrene microspheres was calculated to be 4.26 × 10⁻⁶. -11 N. Simulation analysis shows that the fluid velocity around the long-arm magnetized microrobot is 33.2 μm / s at 3 Hz, while the fluid velocity around the short-axis magnetized microrobot is 10.2 μm / s; unless otherwise specified, this velocity is the fluid velocity at a distance of 10 μm from the vortex center. The viscous drag on polystyrene microspheres at low Reynolds numbers is given by Stokes' law:

[0097] F drag ≈6πμR(UV);

[0098] Where μ represents the dynamic viscosity of methylcellulose at 0.4% w / v, which has been measured to be 15.05 mPa·s; R is the radius of the payload (10 μm); U is the fluid velocity; and V is the velocity of the payload, i.e., the ratio of displacement to time of the microrobot. Calculations show that the viscous drag generated by the long-arm magnetized microrobot and the short-axis magnetized microrobot are 9.4 × 10⁻⁶ mPa·s, respectively. -8 N, 2.9 × 10 -8 N. The upward viscous drag generated by the microrobot is much greater than F. g -F b Therefore, the vortex can lift and capture the object; and when the object is captured, the distance between the center of the sphere and the microrobot is about 35μm.

[0099] Simulation diagrams of the rolling foreground of the microrobot obtained in Examples 1 and 2 are shown below. Figure 3As shown in the figure. The red arrows in the figure illustrate the motion of the surrounding fluid during the rolling process. During the simulation, the two micro-robots rotated in place in space without making any displacement.

[0100] Test Example 3

[0101] This example tests the non-contact transport of a load by the long-arm magnetized robot obtained in Example 1 under a rotating magnetic field of 8 mT at different rotation frequencies (2 Hz, 3 Hz, 4 Hz, 5 Hz, 6 Hz, 7 Hz, 8 Hz, and 9 Hz). Except for the rotation frequency, other parameters, materials, and test results are the same as in Example 2. The test results show that when the rotating magnetic field frequency is below 2 Hz, the vortex generated by the microrobot is insufficient to capture the load. When the frequency is between 3 Hz and 8 Hz, the microrobot can use vortices to capture the load. However, when the rotation frequency of the magnetic field exceeds 9 Hz, the vortex generated by the microrobot's rotation will throw the load away, leading to transport failure. Therefore, for the long-arm magnetized microrobot, the frequency between 3 Hz and 8 Hz is suitable for long-distance transport of loads at 8 mT. Specific test results are as follows... Figure 4 As shown.

[0102] Test Example 4

[0103] This example tests the number of objects simultaneously transported by the microrobots obtained in Examples 1 and 2; the field strength of the rotating magnetic field is 8 mT, and the rotation frequency is 3 Hz; other test conditions, material selection, and test results are the same as in Example 2. The test results show that under the above conditions, the long-arm magnetized microrobot can transport a maximum of 4 objects simultaneously, and the size and range of the vortex are insufficient to support the simultaneous transport of 5 objects. The long-arm magnetized microrobot uses vortexes for non-contact transport, so the number of objects transported does not significantly affect the speed of the long-arm magnetized microrobot itself. The speeds of the microrobots transporting single and multiple objects are both around 30 μm / s at 8 mT and 3 Hz. A detailed transport diagram is shown below. Figure 5 As shown; the specific transportation speed results are statistically as follows: Figure 6 As shown. Correspondingly, under the above conditions, the short-axis magnetized microrobot can also achieve simultaneous transport of multiple objects, as shown in the specific results. Figure 10 As shown.

[0104] It should be further noted that, within the scope provided by this invention, adjusting the rotation frequency, magnetization intensity, external magnetic field intensity, etc., can further increase the number of objects that can be carried simultaneously.

[0105] Test Example 5

[0106] This example tests the performance of the microrobot obtained in Example 1 in directional and point-to-point transport of a load. The parameters of the fluid, the load, and the external magnetic field are the same as in Example 2. The specific process is as follows: the microrobot captures the load at a frequency of 3Hz, transports it to the designated location, and then stops moving. Once the load has descended to the bottom, the microrobot is driven away at a frequency of 0.5Hz. Using a lower frequency to leave is to prevent the microrobot from rotating and carrying the load away from the designated location. To ensure the accuracy of the load's position, only one load is transported at a time. Ultimately, the microrobot arranges the loads to form the letters "S", "U", and "T". The positional deviation between the actual arrival position and the designed arrival position of each load is ≤20μm, or even approximately 0. Specific test results are as follows: Figure 7 As shown.

[0107] Test Example 6

[0108] This example simulates the interlayer binding energy of the microrobots obtained in Example 1 and Comparative Example 1 using BIOVIA Materials Studio software. First, the software was used to draw single molecular chains of SU-8 2005 photoresist, and then 20 molecular chains were aggregated to obtain a polymer. Adsorption simulations were performed on 200 cobalt and titanium atoms respectively with the polymer. The adsorption simulation results showed that the binding energy between titanium and the polymer was 5.7 eV, and the binding energy between cobalt and the polymer was 1.28 eV. The results show that the interlayer binding energy of the microrobot obtained in Example 1 is 5.7 eV; the interlayer binding energy of the microrobot obtained in Comparative Example 1 is 1.28 eV. Therefore, it can be seen that the present invention significantly increases the interlayer binding energy of the obtained microrobot by adjusting the structure and material of each layer, thereby improving the performance and lifespan of the obtained microrobot. Specific binding energy comparisons are as follows: Figure 8 As shown.

[0109] In traditional technologies, if a linear microrobot or a spiral microrobot with a tubular head is used, the rotating vortex generated during the capture process holds the object near the tubular head. These microrobots, with their magnetization direction longitudinally, can only transport a single object multiple times under the drive of the rotating magnetic field, regardless of parameter adjustments; they cannot transport multiple objects simultaneously. Other technologies employ piston-type microrobots, which can simultaneously capture and release multiple objects, but cannot achieve fixed-point transport. Imagine the microrobot provided by this invention; if designed in a linear shape while maintaining its layered structure, it would, like traditional technologies, be unable to form a vortex similar to that of this invention, thus preventing the simultaneous transport of multiple objects. The microrobot provided by this invention, through the design of a special shape, structure, and magnetization direction, combined with the design of parameters such as the magnetic field during transportation, can not only achieve simultaneous transportation of multiple objects but also point-to-point transportation of objects. Furthermore, since it can achieve lossless transportation of polystyrene objects, it is also expected to achieve point-to-point, lossless transportation of fragile objects such as cells, microorganisms, and protein crystals, either in vivo or in vitro. Compared with traditional technologies, the technical solution provided by this invention represents a significant technological breakthrough.

[0110] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.

Claims

1. A method for non-contact transport of goods using a microrobot, characterized in that, The method includes the microrobot rotating under the action of a rotating magnetic field, causing the surrounding fluid to generate vortices; the load is captured by the vortex and transported to a designated location along with the movement of the microrobot; The micromachine includes a first arm and a second arm connected in a V-shape; and both the first arm and the second arm are composed of a polymer layer, a first titanium layer, a magnetic layer and a second titanium layer stacked together. The microrobot is a long-arm magnetized microrobot, and the magnetization direction of the long-arm magnetized microrobot is parallel to the first arm or the second arm; or, the microrobot is a short-axis magnetized microrobot, and the magnetization direction of the short-axis magnetized microrobot coincides with the direction of the bisector of the angle between the first arm and the second arm.

2. The method according to claim 1, characterized in that, The included angle between the first arm and the second arm is 100~135°; and / or; the material of the magnetic layer includes at least one of cobalt and nickel.

3. The method according to claim 1, characterized in that, The method for preparing the microrobot includes: Provide a polymer core with a V-shaped structure; The first titanium layer, the cobalt layer, and the second titanium layer are sequentially sputtered onto the polymer core to form the first and second arms connected in a V-shape.

4. The method according to claim 3, characterized in that, The preparation method also includes demagnetizing and remagnetizing the obtained microrobot sequentially.

5. The method according to claim 1, characterized in that, During the transport process, the load experiences an upward viscous resistance on the order of 10. -8 N; and / or, the difference between the gravity and buoyancy acting on the load is on the order of 10. -13 N.

6. The method according to claim 5, characterized in that, The viscous resistance F drag ≈6πμR (UV); Where μ represents the dynamic viscosity of the fluid, in mPa·s; R represents the radius of the object, in μm; U represents the velocity of the fluid, measured in μm / s; V represents the velocity of the object, measured in μm / s.

7. The method according to any one of claims 1 to 6, characterized in that, The rotation frequency of the microrobot is 3~8Hz; and / or the field strength of the rotating magnetic field is 3~8mT.

8. The method according to any one of claims 1 to 6, characterized in that, The maximum number of items that the microrobot can carry in a single trip is ≥2.

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