A graphene microrobot based on nanomagnetic editing and its preparation and application

Abstract

The present invention belongs to the field of micro-nano device technology, specifically a graphene microrobot based on nanomagnetic editing and its preparation and application. The microrobot of the present invention comprises: two or more nanomagnetic editing arrays, a hard block layer covering the nanomagnetic editing array, and a soft graphene hinge connected between the hard block layers; the nanomagnetic editing array is a two-dimensional array composed of single-domain magnets, which is magnetically edited by an external magnetic field to define the magnetization configuration of the microrobot and control the deformation behavior of the microrobot; under a specific external magnetic field, the microrobot deforms at the graphene hinge, causing the entire microrobot to undergo target deformation behavior; that is, the nanomagnetic array acts as a driving component to drive the microrobot to move, and as a functional unit, changes the shape of the microrobot through real-time magnetic field modulation. The present invention utilizes a graphene microrobot to achieve fixed-point transportation of micro-cargo, with a controllable process, biocompatibility, and a variety of deformable shapes, and has application prospects in the field of micro-nanotherapy in vivo.

Description

Technical Field

[0001] The present invention belongs to the technical field of micro-nano devices, and in particular relates to a graphene microrobot based on nanomagnetic editing and its preparation and application. Background Art

[0002] With the continuous advancement of micro-nano fabrication technology, microrobotics has experienced rapid development. Its main applications in in vivo medical treatment are minimally invasive surgery, targeted drug therapy, and disease monitoring. Magnetic microrobots used in minimally invasive surgery and targeted drug delivery can be driven and controlled wirelessly, showing great application prospects in these fields.

[0003] While researchers at home and abroad have proposed numerous deformable microrobots for minimally invasive surgery and targeted drug delivery, few have combined these two functions for medical diagnosis and treatment. This integration of multiple functions requires microrobots to be more intelligent, controllable, responsive to external stimuli, and capable of adopting a variety of deformable shapes. However, current material design and fabrication methods make it difficult to fabricate intelligent, multi-morphable microrobots at scales of tens of microns.

[0004] To address these challenges, it is necessary to improve the microrobot's deformability and intelligence, combining it with its medical applications in minimally invasive surgery and targeted cargo and drug delivery. By leveraging novel fabrication methods, a novel microrobot capable of intelligently adapting to various shapes is needed. To fabricate intelligent microrobots, a new semiconductor-based microrobot release process is essential. Summary of the Invention

[0005] The purpose of the present invention is to provide a graphene microrobot with multiple deformation forms and a preparation method and application thereof.

[0006] The graphene microrobot provided by the present invention is based on nanomagnetic editing technology, comprising: two or more (i.e., more than two) nanomagnetic editing arrays, hard block layers respectively covering the two or more nanomagnetic editing arrays, and a soft graphene hinge connecting the two or more hard block layers. Figure 1 The nanomagnetic editing array is a 5-20 μm array composed of repeatedly arranged single-domain magnets. The shape of the microrobot is defined by magnetic editing through an external magnetic field. Under a specific external magnetic field, the nanomagnetic editing-based microrobot can deform at the graphene hinge, causing the entire microrobot to undergo targeted deformation behavior.

[0007] The two or more nanomagnetic editing arrays are respectively composed of two or more nanomagnetic units with different aspect ratios. The nanomagnetic units are in the shape of a standard track and field. The length of the nanomagnetic units is 300-600 nm, the width is 60-140 nm, and the thickness is 40-100 nm.

[0008] The material of the nanomagnetic editing array is a single-domain magnet with three dimensions on a scale of 60-600 nm.

[0009] The nanomagnetic editing array is obtained by placing a sample carrying the nanomagnetic array in a magnetic field and applying a specific magnetic field along the long axis of the nanomagnetic rod to magnetically edit the nanomagnetic array. Here, applying a specific magnetic field to magnetically edit the nanomagnetic array is specifically as follows: because nanomagnets have different coercive forces depending on their different geometric shapes, when applying a specific magnetic field to the nanomagnetic array and magnetizing it, the overall magnetization configuration of the microrobot is designed, first magnetizing the high-coercive force nanomagnet array (i.e., applying a magnetic field exceeding the high coercive force to magnetize it), and then magnetizing the low-coercive force nanomagnet array (applying a magnetic field exceeding the low coercive force but not exceeding the high coercive force to magnetize it).

[0010] The nanomagnetic array is made of magnetic materials that can respond to rotating magnetic fields, gradient magnetic fields, static magnetic fields and the combined magnetic fields of the three.

[0011] The nanomagnetic array is selected from ferromagnetic materials such as Co, Cr, Ni, and Al.

[0012] The magnetic material includes one or more materials having single-domain magnetic properties at the nanoscale.

[0013] The hard block layer is a rectangular or square thin film with a total thickness not exceeding 100 nm, such as a thickness of 50-100 nm.

[0014] The material of the hard block layer is selected from Cr, Al, Au and the like.

[0015] The graphene hinge is made of a single-layer graphene with a thickness of a single atomic layer (less than 1 nm). The length of the graphene hinge connecting the two hard plate layers is 5-100 μm.

[0016] The present invention also provides a method for preparing a graphene microrobot based on nanomagnetic editing, specifically, first preparing a nanomagnetic array on the graphene surface, magnetically editing the nanomagnetic array, then covering the nanomagnetic editing array with a hard block layer, and finally etching the graphene into graphene hinges, and finally releasing the microrobot into a working environment.

[0017] The nanomagnetic array is prepared by electron beam exposure to form a repetitive single nanomagnetic pattern, developing the nanomagnetic array pattern, and then depositing the desired magnetic material by electron beam evaporation. The nanomagnetic array is then subjected to a lift-off metal stripping process.

[0018] The method for magnetically editing the nanomagnetic array is to place the nanomagnetic array sample in a magnetic field and apply a specific magnetic field along the long axis of the nanomagnetic rod to magnetize the nanomagnetic array so that it has a specific magnetization configuration, thereby defining the deformation behavior of the microrobot.

[0019] The specific magnetic field is applied to magnetize the nanomagnetic array, specifically: first magnetize the nanomagnetic array with high coercivity, that is, apply a magnetic field exceeding the high coercivity to magnetize it; then magnetize the nanomagnetic array with low coercivity, that is, apply a magnetic field exceeding the low coercivity but not exceeding the high coercivity to magnetize it;

[0020] The hard block layer is prepared by: after the nanomagnetic editing array is prepared, a pattern alignment process is performed to obtain a hard block layer pattern, and then the desired hard block layer material is deposited by electron beam evaporation, and then a lift-off metal stripping process is performed to obtain the hard block layer;

[0021] The graphene hinge is prepared by: obtaining a photoresist pattern of the graphene layer by aligning the hard block layer through a plate-making operation, etching away excess graphene by ion beam etching, and then washing away the photoresist to obtain the graphene hinge;

[0022] The method for releasing the microrobot from the substrate into the working environment is as follows: after the microrobot is prepared, a PVA water-soluble sacrificial layer, a PMMA A4 protective layer and UV photoresist are spin-coated, the protective layer shape is made by UV lithography or laser direct writing, the unnecessary parts are removed by dry etching, and then the microrobot is separated from the substrate by XeF2 dry etching, and finally the microrobot is released into the working environment through the micro-operation table; this release process can also be used when preparing other devices; it is a new release process adapted to semiconductor processes.

[0023] The present invention also provides applications for nanomagnetically edited graphene robots for targeted cargo transport within the body. Specifically, when the nanomagnetically edited graphene robot is placed in a specific magnetic field, the magnetically edited nanomagnetic array causes the graphene to deform, causing the microrobot to deform and capture the microcargo through deformation. Once the microrobot reaches a designated location under the guidance of the magnetic field, changes in the specific magnetic field cause the microrobot to deform and release the microcargo, achieving targeted microcargo transport.

[0024] The present invention also relates to a micro-cargo transport device, which contains the graphene robot based on nanomagnetic editing.

[0025] Compared with the prior art, the present invention has the following characteristics:

[0026] (1) In the present invention, the microrobot release process can be used not only for the release of graphene microrobots, but also for the release of other microrobots compatible with semiconductor preparation. The most critical steps are the use of a PVA water-soluble sacrificial layer, a PMMA waterproof layer, a photoresist mask layer, and a dry etching method;

[0027] (2) In the present invention, the nanomagnetic array is an array of repeatedly arranged single-domain magnets, which can be magnetically edited by applying an external magnetic field to define the shape of the microrobot; under a specific external magnetic field, the microrobot based on nanomagnetic editing can deform at the graphene hinge, causing the entire microrobot to undergo targeted deformation behavior;

[0028] (3) The nanomagnetic array and graphene hinge in the present invention can be combined into various shapes and structures. The nanomagnetic array not only serves as a driving component, responds to an external magnetic field, and has the function of driving the entire microrobot, but also serves as a functional unit, which changes the shape of the microrobot through real-time magnetic field modulation. The present invention utilizes the characteristics of the self-driven graphene microrobot that can achieve a variety of deformation forms under nanomagnetic editing, and realizes the fixed-point transportation of micro-cargo. The process is controllable and biocompatible, and the various deformation shapes have important application prospects in the field of micro-nanotherapy in vivo. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The present invention will be further described below with reference to the accompanying drawings and examples.

[0030] Figure 1 Schematic diagram of the structure of the graphene microrobot based on nanomagnetic editing in the present invention.

[0031] Figure 2 a is a scanning electron microscope (SEM) image of a graphene microrobot array based on nanomagnetic editing. Figure 2 b is an optical microscope image of a single graphene microrobot based on nanomagnetic editing. Figure 2 c is the SEM image of a single graphene microrobot based on nanomagnetic editing.

[0032] Figure 3 Figure 2 is an SEM image of two nanomagnetic arrays of different sizes. The array with shorter nanomagnets is named array A, and the array with longer nanomagnets is named array B.

[0033] Figure 4 These are the hysteresis loops of array A and array B. The hysteresis loops obtained from multiple measurements are stable, indicating that the preparation process is controllable.

[0034] Figure 5 is the Raman curve of graphene hinge.

[0035] Figure 6 Simulating Miura folding for graphene microrobots based on nanomagnetic editing.

[0036] The numbers in the figure are: 1 is the nanomagnetic editing array, 2 is the hard block layer, and 3 is the graphene hinge. DETAILED DESCRIPTION

[0037] The present invention will be further described below with reference to the embodiments and accompanying drawings.

[0038] The graphene microrobot based on nanomagnetic editing provided by the present invention is as follows: Figure 1 As shown, the microrobot includes a nanomagnetic editing array 1, a hard block layer 2 covering the nanomagnetic editing array, and a graphene hinge 3 connecting the hard block layers.

[0039] The nanomagnetic arrays are composed of single-domain magnetic units that respond to rotating, gradient, and oscillating magnetic fields. Magnetic materials include all materials that exhibit a single magnetic domain in the 60-600 nm range and can be mass-produced by electron beam evaporation (or other physical vapor deposition).

[0040] The hard block layer 2 is a quadrilateral thin film, typically square or rectangular, composed of materials such as Cr, Al, and Au. The hard block layer material must be precisely deposited onto the nanomagnetic array at a 100 nm scale using electron beam evaporation or other methods. The growth process must also minimize internal stress to ensure a smooth, flat hard block layer.

[0041] The present invention also provides a method for preparing the above-mentioned nanomagnetic editing graphene microrobot, which is as follows: first, a nanomagnetic editing array 1 is prepared on the surface of a graphene sample, and then a hard block layer 2 is covered on the nanomagnetic editing array 1 after magnetic editing, and finally, the graphene is etched into a graphene hinge 3, and finally, the microrobot is released into a working environment.

[0042] The nanomagnetic editing array 1 is prepared by electron beam exposure to obtain a nanomagnetic array pattern, electron beam evaporation to grow the desired magnetic material onto a graphene / germanium substrate, and lift-off to obtain the final nanomagnetic editing pattern. The hard block layer 2 is prepared by using the nanomagnetic editing array as an alignment pattern, laser direct writing (or ultraviolet lithography) to make a hard block layer pattern, electron beam evaporation to cover the hard block layer material onto the nanomagnetic editing array, and lift-off to obtain the final hard block layer pattern, which serves as the non-deformable part of the microrobot. The graphene hinge 3 is prepared by using the hard block layer as an alignment layer, laser direct writing (or ultraviolet lithography) to define the graphene pattern, and plasma etching (RIE) to etch the graphene layer on germanium into the desired graphene hinge pattern. The method for releasing the microrobot from the substrate into the working environment involves covering the prepared microrobot with a water-soluble sacrificial layer of PVA and PMMA. A protective pattern is then created using photoresist via laser direct writing (or UV lithography). The PVA not covered by the photoresist pattern is then etched using RIE until the Ge substrate is exposed. XeF2 is then used to etch away the Ge, leaving the graphene robot suspended in the air with only one side in contact with the PVA. Finally, a micromanipulation platform is used to select the appropriate microrobot and release it into the working liquid.

[0043] The present invention also provides the preparation of the graphene microrobot into a long strip, the simulation of Miura folding at a microscale by magnetic editing, and the application of the microrobot in micro-cargo transportation.

[0044] The following embodiments take a Ni-based nanomagnetic editing array graphene microrobot as an example to further illustrate the present invention.

[0045] Example 1: A long graphene deformable robot with two nanomagnetic editing arrays ( Figure 2 ):

[0046] (1) A single array of 15 μm × 15 μm was exposed on a graphene / germanium sample spin-coated with PMMA A4 photoresist using Zeiss Sigma SEM and Raith Elphy Plus electron beam exposure. The unit patterns in the array were 340 nm × 120 nm (array A) and 400 nm × 90 nm (array B). 5 nm Cr / 60 nm Ni / 5 nm Al were deposited in this order using a Tianxingda TSV700 electron beam evaporation coating instrument at 0.5 Å / s. The nanomagnetic array pattern prepared is shown in the figure below. Figure 3 Then, NanoMOKE 3 from Durham Magneto Optics was used to perform hysteresis loop tests on the nanomagnetic arrays, and the coercive fields of the two arrays were measured ( Figure 4), and then use NanoMOKE 3 to magnetically edit the nanomagnetic arrays. Along the long axis direction of nanomagnet arrays A and B, a magnetic field of about 600 Oersted (exceeding the coercive force of high-coercive-force nanomagnet array B, about 500 Oersted) is first applied. Then, a magnetic field of about 200 Oersted is applied in the opposite direction (exceeding the coercive force of low-coercive-force nanomagnet array A, about 150 Oersted). This makes arrays A and B magnetized along the long axis direction of the nanomagnetic unit, and in opposite directions.

[0047] (2) Using the nanomagnetic array as the alignment layer, a 20 μm × 20 μm square hard block layer was written using a HEIDELBERG μPG501 laser direct writing (or UV lithography) instrument, and then 5 nm Cr / 100 nm Au was sequentially grown using a Tianxingda TSV700 electron beam evaporation at 0.1 Å / s; Figure 2 As shown, 2 represents a hard block layer, which is attached to the nanomagnetic array;

[0048] (3) Using the hard block layer as the alignment layer, a laser direct writing (or UV lithography) instrument of HEIDELBERG model μPG501 is used to write a graphene pattern of 100 μm × 20 μm in length. The excess graphene is etched away by O2 using RIE of Trion T2, leaving the graphene hinge shape, as shown in the figure. Figure 2 c SEM image, the dark strips connecting the hard block layer 2 are graphene hinges; the graphene area is further measured using a Jobin Yvon HR-Evolution 2 micro-Raman instrument; Figure 5 As shown in the figure, the obtained Raman curve shows two typical Raman characteristic peaks of single-layer graphene, which are located at 1582 cm -1 The G peaks at around 2700 cm -1 G' peaks on the left and right;

[0049] (4) Spin-coat 5 wt% PVA at 3000 r / s for 30 s, spin-coat PMMA A4 at 3000 r / s for 30 s, and then spin-coat ARP-3510 T at 3000 r / s. Etch the photoresist protective layer pattern using μPG501 laser direct writing (or UV lithography). Etch away the excess PMMA A4 and PVA using Trion T2 RIE. Etch the germanium substrate under the microrobot using an Xactix XeF2 dry etcher at a gas flow rate of 4 Torr for about 180 s to detach the microrobot from the substrate. Finally, release the microrobot into the aqueous solution using the micromanipulation platform.

[0050] (5) Under an external static magnetic field, rotating magnetic field, or oscillating magnetic field of 1-30 mT, the microrobot is triggered to deform and exhibit a variety of pre-set deformation shapes, which can be deformed from 100 μm in length to about 20 μm in length, showing super strong deformation ability at the micro-nano scale.

[0051] Example 2: A large-area deformable Miura folding nanomagnetic graphene deformable robot used as a retractable interventional stent:

[0052] (1) Using Zeiss Sigma SEM and Raith Elphy Plus electron beam exposure, a single array was exposed on a graphene / germanium sample sheet spin-coated with PMMA A4 photoresist. The array was a parallelogram with a base of 15 μm and a height of 10 μm. Each microrobot had four arrays in total, and the unit patterns in the arrays were 340 nm × 120 nm (array A) and 400 nm × 90 nm (array B). Using a Tianxingda TSV700 electron beam evaporation coating instrument at 0.5 Å / s, 5 nm Cr / 60 nm Ni / 5 nm Al were deposited in sequence. Then, a NanoMOKE 3 from Durham Magneto Optics was used to perform a hysteresis loop test on the nanomagnetic arrays to measure the coercive fields of the two arrays. The nanomagnetic arrays were then magnetically edited using NanoMOKE 3 so that both arrays A and B had magnetization along the long axis of the nanomagnetic unit, as shown in Figure 2. Figure 6 As shown in a; the nanomagnetic editing pattern of the microrobot is four parallelograms. According to the overall magnetization design of the nanomagnet array, specific magnetic fields are applied in the horizontal and vertical directions. A magnetic field of about 600 Oersted is first applied (exceeding the coercive force of the high-coercive force nanomagnet array B, about 500 Oersted), and then a magnetic field of about 200 Oersted is applied in the opposite direction (exceeding the coercive force of the low-coercive force nanomagnet array A, about 150 Oersted), to achieve an array A with two mutually perpendicular magnetization directions and an array B with two mutually perpendicular magnetization directions;

[0053] (2) Using the nanomagnetic array as the alignment layer, a HEIDELBERG μPG501 laser direct writing (or UV lithography) instrument was used to write a 25 μm × 15 μm parallelogram hard block, and then a 5 nm Cr / 100 nm Au layer was sequentially deposited using a Tianxingda TSV700 electron beam evaporation at a speed of 0.1 Å / s;

[0054] (3) Using the hard block layer as the alignment layer, a 100 μm × 20 μm graphene pattern was written using a HEIDELBERG μPG501 laser direct writing (or UV lithography) instrument. The excess graphene was etched away using O2 using RIE on a Trion T2, leaving behind the graphene hinge shape.

[0055] (4) Spin-coat 5 wt% PVA at 3000 r / s for 30 s, spin-coat PMMA A4 at 3000 r / s for 30 s, and then spin-coat ARP-3510 T at 3000 r / s. Etch the photoresist protective layer pattern using μPG501 laser direct writing (or UV lithography). Etch away the excess PMMA A4 and PVA using Trion T2 RIE. Etch the germanium substrate under the microrobot using an Xactix XeF2 dry etcher at a gas flow rate of 4 Torr for about 180 s to detach the microrobot from the substrate. Finally, release the microrobot into the aqueous solution using the micromanipulation platform.

[0056] (5) After the microrobot is pushed to the target position under an external gradient magnetic field of 1-30 mT, an oscillating magnetic field of 3 mT is applied. The microrobot triggers the Miura fold deformation and can shrink to 30% of its original length and pass through the narrow area. The deformation image is shown in the figure. Figure 6 As shown in b; under the stimulation of an external magnetic field, it can stretch again, realizing the function of an interventional stent.

[0057] Example 3: Application of micro-cargo transportation based on nanomagnetic editing graphene robot:

[0058] (1) Zeiss Sigma SEM and Raith Elphy Plus electron beam exposure were used to expose a single array of 15 μm × 15 μm on a graphene / germanium sample spin-coated with PMMA A4 photoresist. The unit patterns in the array were 340 nm × 120 nm (array A) and 400 nm × 90 nm (array B), respectively. 5 nm Cr / 60 nm Ni / 5 nm Al were deposited in this order using a Tianxingda TSV700 electron beam evaporation device at 0.5 Å / s. The hysteresis loop of the nanomagnetic arrays was then tested using NanoMOKE 3 from Durham Magneto Optics to measure the coercive fields of the two arrays. The coercive fields of the two arrays were then measured using NanoMOKE. 3. Perform magnetic editing on the nanomagnetic arrays. First, apply a magnetic field of about 600 Oersteds (exceeding the coercive force of the high-coercive-force nanomagnet array B, about 500 Oersteds) along the long axis of the nanomagnet arrays A and B. Then, apply a magnetic field of about 200 Oersteds in the opposite direction (exceeding the coercive force of the low-coercive-force nanomagnet array A, about 150 Oersteds) so that both arrays A and B are magnetized along the long axis of the nanomagnetic unit in opposite directions.

[0059] (2) Using the nanomagnetic array as the alignment layer, a 20 μm × 20 μm square hard block layer was written using a HEIDELBERG μPG501 laser direct writing (or UV lithography) instrument, and then 5 nm Cr / 100 nm Au was sequentially deposited using a Tianxingda TSV700 electron beam evaporation at a speed of 0.1 Å / s;

[0060] (3) Using the hard block layer as the alignment layer, a 100 μm × 20 μm graphene pattern was written using a HEIDELBERG μPG501 laser direct writing (or UV lithography) instrument. The excess graphene was etched away using O2 using RIE on a Trion T2, leaving behind the graphene hinge shape.

[0061] (4) Spin-coat 5 wt% PVA at 3000 r / s for 30 s, spin-coat PMMA A4 at 3000 r / s for 30 s, and then spin-coat ARP-3510 T at 3000 r / s. Etch the photoresist protective layer pattern using μPG501 laser direct writing (or UV lithography). Etch away the excess PMMA A4 and PVA using Trion T2 RIE. Etch the germanium substrate under the microrobot using an Xactix XeF2 dry etcher at a gas flow rate of 4 Torr for about 180 s to detach the microrobot from the substrate. Finally, release the microrobot into the aqueous solution using the micromanipulation platform.

[0062] (5) Under an external gradient magnetic field of 1-30 mT, the microrobot is driven to the area where the microsphere cargo is located. A rotating magnetic field of 3 mT is applied, and the microrobot rotates to capture the microsphere. Then, the gradient magnetic field and the rotating magnetic field are applied simultaneously, and the microrobot transports the microcargo to the designated location. The rotating magnetic field is stopped to release the microcargo.

[0063] In the above embodiments, the prepared microrobot can have multiple nanomagnetic arrays with different coercive fields, and the shape of the graphene hinge can also have various variations and can be adjusted according to actual conditions.

[0064] The above description of the embodiments is intended to facilitate understanding and use of the invention by those skilled in the art. It will be apparent that those skilled in the art can readily make various modifications to these embodiments and apply the general principles described herein to other embodiments without requiring inventive effort. Therefore, the present invention is not limited to the above-described embodiments. Improvements and modifications made by those skilled in the art based on the disclosure of the present invention, without departing from the scope of the present invention, should be within the scope of protection of the present invention.

Claims

1. A graphene microrobot based on nanomagnetic editing, characterized in that: include: Two or more nanomagnetic editing arrays, hard block layers respectively covering the two or more nanomagnetic editing arrays, and a soft graphene hinge connecting the two or more hard block layers; wherein the nanomagnetic editing array is a 5-20 μm two-dimensional array composed of repeatedly arranged single-domain magnets, and the shape of the microrobot is defined by magnetic editing through an external magnetic field; under a specific external magnetic field, the nanomagnetic editing-based microrobot deforms at the graphene hinge, causing the entire microrobot to undergo targeted deformation behavior; The two or more nanomagnetic editing arrays are respectively composed of two or more nanomagnetic units with different aspect ratios, and the nanomagnetic units are in the shape of a standard track and field; the nanomagnetic units are 300-600 nm in length, 60-140 nm in width, and 40-100 nm in thickness; The nanomagnetic editing array is obtained by placing a sample carrying the nanomagnetic array in a magnetic field, applying a specific magnetic field along the direction of the long axis of the nanomagnetic rod, and magnetically editing the nanomagnetic array; the magnetic editing of the nanomagnetic array by applying the specific magnetic field is specifically designed according to the overall magnetization configuration of the microrobot, first magnetizing the high-coercive force nanomagnet array, that is, applying a magnetic field exceeding the high coercive force to magnetize it; and then magnetizing the low-coercive force nanomagnet array, that is, applying a magnetic field exceeding the low coercive force but not exceeding the high coercive force to magnetize it; The graphene hinge is made of a single layer of graphene with a thickness of a single atomic layer, and the length of the graphene hinge connecting the two hard plate layers is 5-100 μm; The hard block layer is a rectangular or square thin film with a total thickness of no more than 100 nm; the material of the hard block layer is selected from Cr, Al, and Au.

2. The graphene microrobot according to claim 1, characterized in that: The material of the nanomagnetic editing array is a single-domain magnet with three dimensions on a scale of 60-600 nm.

3. The graphene microrobot according to claim 1, characterized in that: The nanomagnetic array is selected from ferromagnetic materials Co, Cr, Ni, and Al.

4. A method for preparing a graphene microrobot according to any one of claims 1 to 3, characterized in that: First, a nanomagnetic array is prepared on the graphene surface, the nanomagnetic array is magnetically edited, and then a hard block layer is covered on the nanomagnetic editing array. Finally, the graphene is etched into graphene hinges, and finally the microrobot is released into the working environment; wherein: The nanomagnetic array is prepared by electron beam exposure to form a repetitive single nanomagnetic pattern, developing the nanomagnetic array pattern, and then depositing the desired magnetic material by electron beam evaporation. The nanomagnetic array is then subjected to a lift-off metal stripping process. The method for magnetically editing the nanomagnetic array is to place a sample of the nanomagnetic array in a magnetic field, apply a specific magnetic field along the direction of the long axis of the nanomagnetic rod, perform magnetic editing on the nanomagnetic array, define the magnetization configuration of the microrobot, and determine the deformation behavior of the microrobot; The hard block layer is prepared by: after the nanomagnetic editing array is prepared, a pattern alignment process is performed to obtain a hard block layer pattern, and then the desired hard block layer material is deposited by electron beam evaporation, and then a lift-off metal stripping process is performed to obtain the hard block layer; The graphene hinge is prepared by: obtaining a photoresist pattern of the graphene layer by aligning the hard block layer through a plate-making operation, etching away excess graphene by ion beam etching, and then washing away the photoresist to obtain the graphene hinge; The method for releasing the microrobot from the substrate into the working environment is as follows: after the microrobot is prepared, a PVA water-soluble sacrificial layer, a PMMA A4 protective layer and ultraviolet photoresist are spin-coated, the shape of the protective layer is made by ultraviolet lithography or laser direct writing, the unnecessary parts are removed by dry etching, and then the microrobot is separated from the substrate by XeF2 dry etching, and finally the microrobot is released into the working environment through the micro-operation table.

Images