Preparation and editing method of magnetic micro-nanorobot with in-situ re-editing capability

Abstract

The application discloses a preparation and editing method of a magnetic micro-nano robot with in-situ re-editing capability, and belongs to the field of micro-nano devices. The method comprises the following steps: preparing a sacrifice layer by polyvinyl alcohol, spin-coating pNIPAM to prepare a flexible hinge layer by using a photoetching process, and preparing two magnetic driving modules by using SU-8 of pre-mixed nickel nanowires with different diameters, so as to obtain the micro-nano robot after releasing. When re-editing, one of the magnetic driving modules or both of the magnetic driving modules can be selectively magnetized by an external magnetic field, and the in-situ re-editing of the micro-nano robot is completed. The preparation process of the application is simple, the re-editing of the micro-nano robot can be realized by the simple external magnetic field, more movement modes are provided, the problems of the existing micro-nano device movement modes still being rigid and the like are solved, the flexibility is further improved, and the application has important application prospects in the fields of biological medicine, environmental detection and the like.

Description

Technical Field

[0001] This invention relates to the fabrication and editing methods of magnetic micro / nano robots with in-situ re-editing capabilities, belonging to the field of micro / nano device technology. Background Technology

[0002] With the rapid development of micro-nano technology and the increasing demands in the biomedical field, magnetic micro-nano robots have become a research hotspot. Due to their small size, remote controllability, recyclability, and multifunctionality, they have potential applications in biomedical fields such as drug delivery, imaging, surgery, and diagnostics. However, in the biological tissue environment of the human body, such as blood vessels and intestines, solid surfaces are uneven and have complex shapes, which hinders the movement of magnetic micro-nano robots. One way to improve the adaptability of micro-nano robots to their working environment is to endow them with multimodal motion capabilities.

[0003] Currently, the multimodal operation of magnetically driven micro- and nano-robots is mainly achieved by changing the magnitude and type of the magnetic field or by magnetically editing the micro- and nano-robots to alter their magnetism. While changing the magnitude and type of the magnetic field can effectively alter the motion modes of micro- and nano-robots, existing motion modes remain relatively rigid and lack flexibility.

[0004] Magnetic editing of micro- and nano-robots is divided into pre-editing and real-time editing. Pre-editing refers to introducing a certain external field during the fabrication process of the micro- and nano-robot to magnetize different regions within the micro- and nano-robot to different states. However, this method can only produce one pre-magnetization direction, which cannot be changed. Real-time editing refers to the ability to change the magnetic state of the micro- and nano-robot even after it has been released into the working environment. This method can complete different magnetic state editing for the same micro- and nano-robot, adapting to complex environments.

[0005] Magnetic editing through means other than magnetic fields is a common method, but increasing the type of external field increases the difficulty of driving micro- and nano-robots. Summary of the Invention

[0006] The purpose of this invention is to provide a method for fabricating and editing magnetic micro / nano robots with in-situ re-editing capabilities. This method reduces the size of editable magnetic micro / nano robots to hundreds of micrometers in a simpler way, and enables magnetic editing and motion deformation control using only a magnetic field.

[0007] As one aspect of the present invention, a magnetic micro / nano robot with in-situ re-editing capability is provided, comprising a magnetic drive layer and a flexible hinge layer. The magnetic drive layer includes a first magnetic drive module and a second magnetic drive module, which are connected through the flexible hinge layer.

[0008] The first magnetic drive module is prepared using a first magnetic particle-containing photoresist, and the second magnetic drive module is prepared using a second magnetic particle-containing photoresist. The coercivity of the first magnetic drive module is greater than that of the second magnetic drive module.

[0009] The first magnetic drive module and the second magnetic drive module are used to perform in-situ re-editing after the first magnetic field and the second magnetic field are applied sequentially. The first magnetic field is used to align the first magnetic drive module and the second magnetic drive module with the direction of the first magnetic field. The second magnetic field is used to perform in-situ re-editing of the first magnetic drive module and the second magnetic drive module. The strength of the first magnetic field is less than the coercivity of the second magnetic drive module. The strength of the second magnetic field is greater than the coercivity of the second magnetic drive module and less than the coercivity of the first magnetic drive module. The direction of the second magnetic field is opposite to the direction of the first magnetic field.

[0010] Preferably, the first magnetic drive module is prepared using SU-8 photoresist containing nickel nanowires with a diameter of 70 nm, and the second magnetic drive module is prepared using SU-8 photoresist containing nickel nanowires with a diameter of 200 nm.

[0011] Preferably, the second magnetic field is a uniform magnetic field of 18mT to 36mT.

[0012] Preferably, the first magnetic field is a uniform magnetic field of 15 mT, and the second magnetic field is a uniform magnetic field of 33 mT.

[0013] Preferably, the flexible hinge layer is prepared using poly-N-isopropylacrylamide.

[0014] As another aspect of the present invention, a method for fabricating and editing a magnetic micro / nano robot with in-situ re-editing capability is provided, comprising:

[0015] Step 1: Prepare the substrate layer;

[0016] Step 2: Spin-coat a water-soluble sacrificial layer onto the substrate and dry it to remove moisture from the water-soluble sacrificial layer;

[0017] Step 3: Spin-coat a flexible hinge layer onto the surface of the water-soluble sacrificial layer and pattern the flexible hinge layer.

[0018] Step 4: Continue spin coating the first magnetic particle photoresist, place the silicon wafer in a uniform magnetic field and heat at 65°C for 3 minutes, then heat at 95°C for 6 minutes, and perform patterning; spin coating the second magnetic particle photoresist, place the silicon wafer in a uniform magnetic field and heat at 65°C for 3 minutes, then heat at 95°C for 6 minutes, and perform patterning.

[0019] Step 5: Remove the sacrificial layer and release the micro-nano robots;

[0020] Step 6: Applying a magnetic field larger than that of the nickel nanowires can re-magnetize the micro / nano robots;

[0021] Step 7: Use an oscillating magnetic field to control the deformation motion of the micro-nano robot.

[0022] Preferably, the substrate material in step 1 is a silicon wafer;

[0023] Preferably, a 5% polyvinyl alcohol sacrificial layer is prepared using spin coating technology, with deionized water as the solvent, and a spin coater is used for both spin coating and deionization.

[0024] Preferably, in step 3, the flexible hinge layer is poly-N-isopropylacrylamide, the patterning process is performed using photolithography, and the development process is performed using chloroform.

[0025] Preferably, the first magnetic particle photoresist in step 4 is SU-8 photoresist containing nickel nanowires with a diameter of 70 nm, and the second magnetic particle photoresist in step 4 is SU-8 photoresist with nickel nanowires with a diameter of 200 nm.

[0026] Preferably, the heating in the uniform magnetic field in step 4 is achieved using a device consisting of a Hellbeck array and a cylindrical heating stage embedded therein, wherein the Hellbeck array provides a uniform magnetic field higher than 300 mT and the cylindrical heating stage provides a heating temperature within 300 °C.

[0027] Preferably, the specific method for removing the sacrificial layer in step 5 is to immerse the patterned silicon wafer in deionized water and release the micro-nano robot into the glass sample cell or the silicon wafer sample cell.

[0028] Preferably, the second magnetic field in step 6 is controlled by a 3D Helmholtz coil, and the magnetization magnetic field range is 18mT to 36mT.

[0029] Preferably, step 6 involves first applying a first magnetic field of 15mT to the micro-nano robot to align the first magnetic drive module and the second magnetic drive module of the micro-nano robot with the direction of the first magnetic field, and then applying a second magnetic field of 33mT with an excitation time of less than or equal to 10ms to magnetize the micro-nano robot.

[0030] Preferably, the vibration magnetic field in step 7 is controlled by a 3D Helmholtz coil, and the applied magnetic field is less than 18mT.

[0031] Preferably, the flexible hinge layer prepared by poly-N-isopropylacrylamide has a rectangular pattern with a side length of 100 μm to 550 μm.

[0032] Preferably, the first driving module fabricated with SU-8 photoresist containing nickel nanowires with a diameter of 70 nm has a square pattern with a side length of 100 μm to 200 μm, and the second driving module fabricated with SU-8 photoresist containing nickel nanowires with a diameter of 200 nm has a square pattern with a side length of 100 μm to 200 μm.

[0033] This invention employs the principle of photolithography to fabricate a magnetic micro / nano robot with in-situ re-editing capabilities using a three-layer overlay process. A water-soluble sacrificial layer is used to detach the robot from the silicon wafer and release it into a liquid environment. A two-step re-editing and magnetization process is employed: first, a smaller first magnetic field is applied to align the two magnetic drive modules with the direction of the first magnetic field; then, a larger, opposite second magnetic field is applied to magnetize the two magnetic drive modules, achieving in-situ re-editing of the micro / nano robot. This invention programs the magnetic configuration of the single-domain nanomagnet array on the connection panel, encoding multiple shape deformation commands into the micro / nano robot. This programming is achieved by applying a specific sequence of magnetic fields to nanomagnets with appropriately customized switching fields. Then, a simple external magnetic field is used to achieve customized shape transformations of the micro / nano robot, i.e., re-editing. This solves the problem of the relatively rigid motion modes in existing systems, providing more motion modes and further improving flexibility. Furthermore, the motion modes can be adjusted through in-situ re-editing, enhancing the adaptability and flexibility of the micro / nano robot in actual working environments. Based on these characteristics, it will be able to overcome various complex environments within the human body and achieve precise treatment in the future.

[0034] Furthermore, this invention is compatible with semiconductor fabrication processes, allowing for the addition of functional layers as needed, such as using a coating process to add a metal layer to enhance conductivity. It also offers flexible structural design, enabling the shape of the micro / nano robot to be flexibly designed using a photomask. The photolithography process simplifies the magnetically editable micro / nano robot while further reducing its size; the photomask linewidth accuracy can reach 5μm, and the ultraviolet wavelength is below 400nm. Shortening the length of the nickel nanowires can further reduce the size of the magnetically editable micro / nano robot.

[0035] Compared with the prior art, the present invention has the following advantages:

[0036] 1. This invention uses photolithography to prepare the micro-nano robots, which is simple, environmentally friendly, and easy to operate. The resulting micro-nano robots are small in size and can be mass-produced.

[0037] 2. This invention mixes nickel nanowires with SU-8, cleverly utilizing the heating and curing process of SU-8 to apply a uniform magnetic field to magnetize the nickel nanowires. After the SU-8 is completely cured, the nickel nanowires are oriented. Furthermore, the nickel nanowires are mixed with photoresist to encapsulate them internally, reducing the impact of the environment on the nickel nanowires and enhancing their stability. At the same time, it also reduces the impact of nickel nanowires on the biological environment during practical applications.

[0038] 3. The polyvinyl alcohol, poly-N-isopropylacrylamide, and SU-8 used in this invention as components of the micro-nano robot are all biocompatible. The nickel nanowires are encapsulated inside SU-8 and can be directly used in biological experiments.

[0039] 4. In the process of re-editing the micro / nano robot, this invention first uses a small magnetic field to deflect and orient the robot, then applies a large magnetic field for magnetization. This ensures that the magnetic field inside the micro / nano robot is exactly opposite to the direction of the magnetic field, effectively magnetizing the nickel nanowires. Thus, the re-editing of the micro / nano robot can be achieved through a simple external magnetic field, providing more motion modes and solving the problem of the existing motion modes being relatively rigid, further improving flexibility. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 A schematic diagram illustrating the steps of the fabrication method of the magnetic micro / nano robot with in-situ re-editing capability provided by the present invention;

[0042] Figure 2 A schematic diagram of the apparatus provided by the present invention for curing SU-8 photoresist and magnetizing nickel nanowires;

[0043] Figure 3a This is a schematic diagram of an array of magnetic micro / nano robots with in-situ re-editing capabilities prepared according to the present invention.

[0044] Figure 3b This is a schematic diagram of a single magnetic micro / nano robot with in-situ re-editing capability fabricated according to the present invention;

[0045] Figure 3c A schematic diagram of a single micro-nano robot being released into water;

[0046] Figure 4aThis is a schematic diagram of the in-situ re-editing process where the magnetization directions of the first and second magnetic drive modules of the magnetic micro / nano robot with in-situ re-editing capability prepared by the present invention change from the same direction to opposite directions.

[0047] Figure 4b This is a schematic diagram illustrating the in-situ re-editing process of the first and second magnetic drive modules of the magnetic micro / nano robot with in-situ re-editing capability prepared in this invention, where the magnetization directions change from opposite to the same direction.

[0048] Figure 5a A schematic diagram of the internal magnetism of the magnetic micro / nano robot with in-situ re-editing capability prepared for this invention, when the first and second magnetic drive modules are in the same direction.

[0049] Figure 5b The diagram shows the deformation response of the magnetic micro / nano robot with in-situ re-editing capability to an oscillating magnetic field when the first and second magnetic drive modules are in the same direction.

[0050] Figure 5c A schematic diagram of the internal magnetism of the magnetic micro / nano robot with in-situ re-editing capability prepared in this invention when the first and second magnetic drive modules are reversed.

[0051] Figure 5d This is a schematic diagram showing the deformation response of the magnetic micro / nano robot with in-situ re-editing capability to an oscillating magnetic field when the first and second magnetic drive modules are reversed.

[0052] The numbers in the figure are: 1-substrate layer, 2-water-soluble sacrificial layer, 3-flexible hinge layer, 4-first magnetic drive module, 5-second magnetic drive module. Detailed Implementation

[0053] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0054] Example 1:

[0055] This invention provides a magnetic micro / nano robot with in-situ re-editing capability, comprising a magnetic drive layer and a flexible hinge layer. The magnetic drive layer includes a first magnetic drive module and a second magnetic drive module, which are connected through the flexible hinge layer.

[0056] The first magnetic drive module is SU-8 photoresist containing nickel nanowires with a diameter of 70 nm, the second magnetic drive module is SU-8 photoresist containing nickel nanowires with a diameter of 200 nm, and the flexible hinge layer is poly-N-isopropylacrylamide. The coercivity of the nickel nanowires in the first magnetic drive module is 74 mT, and the coercivity of the nickel nanowires in the second magnetic drive module is 18 mT.

[0057] The first and second magnetic drive modules are used to perform in-situ re-editing after sequentially applying a first magnetic field of 15mT and a second magnetic field of 33mT. Specifically, the first magnetic field is used to align the first and second magnetic drive modules with the direction of the first magnetic field. Then, the second magnetic field will cause the robot to turn so that it aligns with the second magnetic field in the opposite direction. However, since the 200nm diameter nickel nanowires have low coercivity and are easy to magnetize, they will be magnetized before the robot can turn completely. The magnetization directions of the two nickel nanowires are opposite, thus achieving in-situ re-editing of the robot.

[0058] The magnetic micro / nano robot with in-situ re-editing capability provided by the embodiments of the present invention is small in size, simple in preparation process, and can be repeatedly edited by applying a magnetic field. It is very easy to operate and has more motion modes, which solves the problem that the motion modes of existing micro / nano robots are still relatively rigid, further improving the flexibility of micro / nano robots and has broad application prospects in the biomedical field.

[0059] Example 2:

[0060] This embodiment provides a method for fabricating a magnetic micro / nano robot with in-situ re-editing capabilities. See [link to documentation]. Figure 1 ,include:

[0061] (a) A silicon wafer is used as the substrate layer 1. The water-soluble sacrificial layer 2 is 5% polyvinyl alcohol. The sacrificial layer is spin-coated onto the substrate surface to form a thin film using a spin coater at a speed of 1500 rpm / min and a thickness of approximately 2 μm. After spin coating, the moisture in the polyvinyl alcohol is dried using a 95°C heating table.

[0062] (b) 15 mg / ml of poly-N-isopropylacrylamide was spin-coated onto the surface of the sacrificial layer to form a thin film at a spin coater of 1500 rpm / min and a thickness of about 100 nm. The poly-N-isopropylacrylamide was patterned using a UV lithography machine with a mask for 360 s. After the process, it was developed with chloroform for 1 min to obtain a square patterned flexible hinge layer 3.

[0063] (c) SU-8 photoresist, uniformly mixed with 70 nm diameter nickel nanowires, was spin-coated onto the flexible hinge layer 3 using a spin coater. The nickel nanowire mass fraction was 2%, the spin coating speed was 4000 rpm / min, and the thickness was approximately 30 μm. Simultaneously, the nickel nanowire array was magnetized using a Helbeck array while the SU-8 was thermally cured.

[0064] (d) SU-8 containing nickel nanowires with a diameter of 70 nm is patterned using an overlay process so that SU-8 is exactly on one side of the poly-N-isopropylacrylamide pattern. After alignment, it is exposed for 18 seconds. After completion, it is developed to obtain the first magnetic drive module 4.

[0065] (e) SU-8 photoresist, uniformly mixed with 200 nm diameter nickel nanowires, was spin-coated onto the flexible hinge layer 3 using a spin coater. The nickel nanowire mass fraction was 2%, the spin coating speed was 4000 rpm / min, and the thickness was approximately 30 μm. Simultaneously, the nickel nanowire array was magnetized using a Helbeck array while the SU-8 was thermally cured.

[0066] (f) SU-8 containing 200 nm diameter nickel nanowires was patterned using an overlay process, ensuring that SU-8 was positioned exactly on the opposite side of the poly-N-isopropylacrylamide pattern. After alignment, exposure was performed for 18 seconds, followed by development to obtain the second magnetic drive module 5. The final product is a magnetically programmable micro / nano robot containing two magnetic drive modules linked together by a flexible hinge.

[0067] (g) Immerse the silicon wafer in water for about 3 minutes until the sacrificial layer is completely dissolved in the water. The robot is then removed from the substrate. Use a pipette to move the single micro-nano robot into the glass sample cell, and then move it into the Helmholtz coil for driving and observation.

[0068] Example 3:

[0069] This invention provides an apparatus for curing and magnetizing SU-8 photoresist containing nickel nanowires, such as... Figure 2 As shown, it consists of a Helbeck array and a heating platform.

[0070] In this embodiment, the Heilbeck array is ring-shaped, with eight cubic neodymium iron boron permanent magnets uniformly and equidistantly embedded on it, their magnetization direction being parallel to... Figure 2 The arrows drawn in the diagram are in the same direction. The eight magnets at the center of the ring enhance the magnetic field strength in the direction of the arrow, canceling out the magnetic field strength in all other directions, and finally forming a unidirectional uniform magnetic field in the direction of the arrow at the center of the Hellbeck array. This array can generate a constant unidirectional static uniform magnetic field of more than 300mT at the center without the need for other energy fields to drive it.

[0071] The heating stage mainly consists of a power supply, a control panel, and a cylindrical heating stage body. The control panel can set the heating temperature to below 300℃. The cylindrical heating stage generates heat only on a single surface, and its size is adapted to the hollow structure of the Hellbeck array, allowing it to be embedded in the center of the Hellbeck array. This enables the SU-8 photoresist to be heated and cured while the nickel nanowires within it are magnetized.

[0072] In addition, there are four channels at the back of the Helbeck array. The function of the channels is to introduce the wires of the heating platform, so that the Helbeck array can remain stable after being introduced into the heating platform and will not affect the direction of the magnetic field. At the same time, opening four directions can flexibly configure the direction of the heating platform's lead wires and adapt to different terrain conditions.

[0073] Example 4:

[0074] The morphological characterization of the magnetic micro / nano robot with in-situ re-editing capability provided in this embodiment of the invention is as follows: Figures 3a to 3c As shown, specifically:

[0075] like Figure 3a As shown, ultraviolet lithography was used to fabricate micro- and nano-robots. A single fabrication of an 8x8 array of 64 micro- and nano-robots was achieved on a 1.5x1.5 cm silicon wafer. Furthermore, by designing the mask, multiple different types of micro- and nano-robots could be fabricated in a single operation. Figure 3a The exhibit showcases a micro-nano robot with a magnetic drive module measuring 100x100μm and a flexible hinge length ranging from 25μm to 100μm.

[0076] Single micro-nano robots, such as Figure 3b As shown, due to the transparent nature of SU-8, the nickel nanowires inside are clearly visible. The nanowires magnetized by the device in Example 3 are neatly arranged, and the addition of nickel nanowires does not affect the photolithographic properties of SU-8, which has sharp edges.

[0077] like Figure 3c As shown, the micro-nano robots released into the water show very little change compared to those not released, and they do not exhibit significant deformation during long-term use, demonstrating stable properties.

[0078] Example 5:

[0079] This invention provides an editing method for a magnetic micro / nano robot with in-situ re-editing capabilities. The method uses nickel nanowires with a diameter of 200 nm and a length of 10 μm and a diameter of 70 nm and a length of 10 μm, respectively, as magnetic response materials in the second and first magnetic drive modules. Their coercivity is 18 mT and 74 mT, respectively. Therefore, after magnetizing the two nanowires in the same direction, when a 33 mT reverse magnetic field is applied to the magnetic robot, the robot will turn to align with the reverse magnetic field. However, because the 200 nm diameter nickel nanowire has low coercivity and is easily magnetized, it will be magnetized before the robot can fully turn. Since the magnetization directions of the two nickel nanowires are opposite, in-situ re-editing of the robot is ultimately achieved. Details are as follows:

[0080] (a) such as Figure 4a As shown, for a micro-nano robot with magnetic drive modules on both sides of the flexible hinge having the same magnetization direction in the initial state, it naturally unfolds in a "I" shape when no magnetic field is applied. Since the coercivity of the 70nm diameter nickel nanowire used in the embodiment of the present invention is 74mT and the coercivity of the 200nm diameter nickel nanowire is 18mT, it still remains in a "I" shape after applying a uniform magnetic field of 15mT. Then, a reverse magnetic field of 33mT with a change rate of less than 10ms is applied and remains unchanged after reaching its maximum value. The side containing the nanowire with smaller coercivity, i.e., the second magnetic drive module, is magnetized to the opposite direction within 10ms, while the side containing the nanowire with larger coercivity, i.e., the first magnetic drive module, is not magnetized. The magnetic drive modules on both sides of the micro-nano robot change to opposite directions. Since the magnetic field of 33mT is still in effect, the micro-nano robot is folded into a "V" shape. After the magnetic field is removed, the micro-nano robot returns to a "I" shape.

[0081] (b) such as Figure 4b As shown, for a micro-nano robot with magnetic drive modules on both sides of the flexible hinge having opposite magnetization directions in the initial state, it naturally unfolds in a "I" shape when no magnetic field is applied. After applying a uniform magnetic field of 15mT, it becomes "V" shaped. Then, a reverse magnetic field of 33mT with a change rate of less than 10ms is applied and remains unchanged after reaching its maximum value. The side containing the nanowire with lower coercivity, i.e., the second magnetic drive module, is magnetized to the opposite direction within 10ms, while the side containing the nanowire with higher coercivity, i.e., the first magnetic drive module, is not magnetized. The magnetic blocks on both sides of the micro-nano robot become the same direction. Since the magnetic field of 33mT is still in effect, the micro-nano robot becomes "I" shaped. After the magnetic field is removed, the micro-nano robot maintains the naturally unfolded "I" shape.

[0082] (c) A 3D Helmholtz coil applies an oscillating magnetic field to control the deformation motion of the micro-nano robot. The applied oscillating magnetic field is less than 18 mT.

[0083] Example 6:

[0084] The deformation and transformation of the magnetic micro / nano robot with in-situ re-editing capability provided in the embodiments of the present invention are as follows: Figures 5a to 5d As shown, specifically:

[0085] (a) For a micro-nano robot with the same magnetization direction on both sides of the flexible hinge magnetic drive module, it naturally unfolds in a "I" shape when no magnetic field is applied. When an oscillating magnetic field with an amplitude of 10mT is applied to it, since the magnetic drive module has the same magnetization direction, the micro-nano robot responds to the oscillating magnetic field as a whole. There is no relative motion inside the robot, and the robot as a whole always flips back and forth in a "I" shape along the direction of the magnetic field.

[0086] (b) For a micro-nano robot with opposite magnetization directions of the magnetic drive modules on both sides of the flexible hinge, it naturally unfolds in a "I" shape when no magnetic field is applied. When an oscillating magnetic field with an amplitude of 10mT is applied to it, the two sides of the flexible hinge inside the micro-nano robot move relative to each other due to the opposite magnetization directions of the magnetic drive modules. The flexible hinge deforms and the robot folds and flips like a butterfly flapping its wings along the direction of change of the oscillating magnetic field.

[0087] Some steps in the embodiments of the present invention can be implemented using software, and the corresponding software program can be stored in a readable storage medium, such as an optical disc or a hard disk.

[0088] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A magnetic micro / nano robot with in-situ re-editing capability, characterized in that, It includes a magnetic drive layer and a flexible hinge layer. The magnetic drive layer includes a first magnetic drive module and a second magnetic drive module, which are connected through the flexible hinge layer. The first magnetic drive module is prepared using a first magnetic particle-containing photoresist, and the second magnetic drive module is prepared using a second magnetic particle-containing photoresist, wherein the coercivity of the first magnetic drive module is greater than that of the second magnetic drive module. The first magnetic drive module and the second magnetic drive module are used to perform in-situ re-editing after sequentially applying a first magnetic field and a second magnetic field. The first magnetic field is used to align the first magnetic drive module and the second magnetic drive module with the direction of the first magnetic field, and the second magnetic field is used to perform in-situ re-editing of the first magnetic drive module and the second magnetic drive module. The strength of the first magnetic field is less than the coercivity of the second magnetic drive module, and the strength of the second magnetic field is greater than the coercivity of the second magnetic drive module and less than the coercivity of the first magnetic drive module. The direction of the second magnetic field is opposite to the direction of the first magnetic field.

2. A magnetic micro / nano robot with in-situ re-editing capability according to claim 1, characterized in that, The first magnetic drive module is fabricated using SU-8 photoresist containing nickel nanowires with a diameter of 70 nm, and the second magnetic drive module is fabricated using SU-8 photoresist containing nickel nanowires with a diameter of 200 nm.

3. A magnetic micro / nano robot with in-situ re-editing capability according to claim 2, characterized in that, The second magnetic field is a uniform magnetic field of 18mT to 36mT.

4. A magnetic micro / nano robot with in-situ re-editing capability according to claim 3, characterized in that, The first magnetic field is a uniform magnetic field of 15 mT, and the second magnetic field is a uniform magnetic field of 33 mT.

5. A magnetic micro / nano robot with in-situ re-editing capability according to claim 1, characterized in that, The flexible hinge layer is prepared using poly-N-isopropylacrylamide.

6. A method for fabricating and editing a magnetic micro / nano robot with in-situ re-editing capability, used to fabricate the magnetic micro / nano robot with in-situ re-editing capability as described in any one of claims 1 to 5, characterized in that, The method includes: Step 1: Prepare the substrate layer; Step 2: Spin-coat a water-soluble sacrificial layer onto the substrate and dry it to remove moisture from the water-soluble sacrificial layer; Step 3: Spin-coat a flexible hinge layer onto the surface of the water-soluble sacrificial layer and pattern the flexible hinge layer. Step 4: Spin-coat the first magnetic particle photoresist onto the surface of the flexible hinge layer, heat and cure it in a uniform magnetic field, and pattern it to obtain the first magnetic drive module; spin-coat the second magnetic particle photoresist onto the surface of the flexible hinge layer, heat and cure it in a uniform magnetic field, and pattern it to obtain the second magnetic drive module, thus obtaining the magnetic drive layer. The coercivity of the first magnetic drive module is greater than that of the second magnetic drive module. Step 5: Remove the sacrificial layer and release the micro-nano robots; Step 6: Apply a first magnetic field to the micro-nano robot to align the first magnetic drive module and the second magnetic drive module with the direction of the first magnetic field. Then apply a second magnetic field to the micro-nano robot to perform in-situ re-editing of the first magnetic drive module and the second magnetic drive module. The strength of the first magnetic field is less than the coercivity of the second magnetic drive module, the strength of the second magnetic field is greater than the coercivity of the second magnetic drive module and less than the coercivity of the first magnetic drive module, and the direction of the second magnetic field is opposite to the direction of the first magnetic field. Step 7: Use an oscillating magnetic field to control the deformation motion of the micro-nano robot.

7. The method according to claim 6, characterized in that, The water-soluble sacrificial layer is prepared using 5% polyvinyl alcohol and deionized water as the solvent.

8. The method according to claim 6, characterized in that, In step 4, the first magnetic particle photoresist is spin-coated on the surface of the flexible hinge layer, heated and cured in a uniform magnetic field, and patterned to obtain the first magnetic drive module. The process is as follows: SU-8 photoresist containing nickel nanowires with a diameter of 70nm is spin-coated on the surface of the flexible hinge layer, heated and cured in a uniform magnetic field, and the SU-8 photoresist containing nickel nanowires with a diameter of 70nm is patterned using an overlay process. After the SU-8 photoresist containing nickel nanowires with a diameter of 70nm is on one side of the flexible hinge layer, exposure and development are performed. In step 4, the second magnetic particle-containing photoresist is spin-coated onto the surface of the flexible hinge layer, heated and cured in a uniform magnetic field, and patterned to obtain the second magnetic drive module. The process involves spin-coating SU-8 photoresist containing nickel nanowires with a diameter of 200 nm onto the surface of the flexible hinge layer, heating and curing in a uniform magnetic field, and using an overlay process to pattern the SU-8 photoresist containing nickel nanowires with a diameter of 200 nm on the other side of the flexible hinge layer before exposure and development.

9. The method according to claim 7, characterized in that, In step 4, heating and curing in a uniform magnetic field refers to heating and curing the SU-8 photoresist in a heating stage at the center of the Hellbeck array and magnetizing the nickel nanowires through the Hellbeck array. The Hellbeck array is used to generate a unidirectional static uniform magnetic field greater than 300mT at the center, and the heating stage is used to provide a heating temperature within 300°C.

10. The method according to claim 9, characterized in that, In step 7, the oscillating magnetic field is controlled by a 3D Helmholtz coil, and the strength of the oscillating magnetic field is less than the coercivity of the second magnetic drive module.

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