Preparation method of core-shell structure magnetic robot

Abstract

A method for preparing a magnetic robot with a core-shell structure belongs to the technical field of magnetic robot preparation. The present invention addresses the problems of existing magnetically driven microrobots, such as the biological toxicity and side effects of raw materials, the complexity of the preparation process, and the high cost. The method comprises: uniformly mixing a gelatin solution and a calcium chloride solution in a ratio of 3:1, and then uniformly mixing with 20nm ferroferric oxide particles at a mass fraction of 5% to 10% to obtain a magnetic mixed solution; cooling the magnetic mixed solution droplets in a petri dish containing liquid paraffin oil to form gelatin spheres with magnetic particles; washing the solution, soaking the solution in a sodium alginate solution for at least 10 seconds, and then removing the solution to form a calcium alginate shell; obtaining an initial magnetic robot with a core-shell structure; then heating the gelatin spheres to melt them, and aligning the magnetic particles in the spheres in a chain-like manner in an adjustable uniform magnetic field; and cooling the solution to obtain the final magnetic robot with a core-shell structure. The present invention is used to prepare a magnetic robot.

Description

Technical Field

[0001] The invention relates to a method for preparing a core-shell structure magnetic robot, and belongs to the technical field of magnetic robot preparation. Background Art

[0002] Due to their tiny structure and controllable navigation capabilities, microrobots can complete designated tasks outside or inside cells and have shown great application potential in many fields, including targeted drug delivery, minimally invasive surgery, and environmental purification.

[0003] Currently, there are many ways to drive microrobots, such as magnetic fields, electric fields, light fields, chemical, and biological actuation, each with its own advantages and disadvantages. A comparison shows that magnetic field actuation offers the advantages of higher biocompatibility, faster response speed and control accuracy, and non-contact remote operation compared to other actuation methods. Therefore, magnetic field actuation has become the mainstream actuation method for microrobots.

[0004] Existing methods for producing magnetic-field-driven microrobots face challenges: the materials used can have biotoxic side effects, and the equipment and processes involved are complex and costly. Furthermore, existing magnetic drive systems are unable to generate high-frequency, high-intensity magnetic fields within a relatively large workspace, hindering the ability of microrobots to function effectively in practical applications. Summary of the Invention

[0005] In view of the problems that the raw materials of existing magnetically driven microrobots have biological toxic side effects, and the preparation process is complicated and costly, the present invention provides a method for preparing a core-shell structured magnetic robot.

[0006] A method for preparing a core-shell structure magnetic robot of the present invention comprises:

[0007] The gelatin solution and the calcium chloride solution are uniformly mixed in a ratio of 3:1, and then uniformly mixed with 20 nm ferroferric oxide particles in a ratio of 5% to 10% by mass to obtain a magnetic mixed solution;

[0008] The magnetic mixture droplets were cooled in a petri dish containing 4-degree Celsius liquid paraffin oil to form gelatin spheres with magnetic particles. The paraffin oil on the surface of the gelatin spheres was cleaned and then immersed in a sodium alginate solution for at least 10 seconds before being removed to form a calcium alginate shell, thereby obtaining an initial magnetic robot with a core-shell structure.

[0009] The initial magnetic robot is heated to melt its gelatin balls, and the magnetic particles therein are assembled in a chain-like manner in an adjustable uniform magnetic field. The robot is then cooled and shaped to obtain the final magnetic robot with a core-shell structure.

[0010] According to the method for preparing the core-shell structure magnetic robot of the present invention, the method for preparing the gelatin solution is:

[0011] The gelatin particles were mixed with deionized water and stirred in a magnetic stirrer at 45 degrees Celsius until completely melted to obtain a 10% wt gelatin solution.

[0012] According to the method for preparing the core-shell structure magnetic robot of the present invention, the method for preparing the calcium chloride solution is as follows:

[0013] Anhydrous calcium chloride particles were mixed with deionized water and stirred in a magnetic stirrer at room temperature until completely melted to obtain a 1% wt calcium chloride solution.

[0014] According to the method for preparing the core-shell structure magnetic robot of the present invention, a needle is used to extract the magnetic mixed liquid, and an extrusion method is used to obtain droplets of the magnetic mixed liquid.

[0015] According to the method for preparing the core-shell structure magnetic robot of the present invention, the gelatin balls are repeatedly washed with water and anhydrous ethanol to remove the paraffin oil on the surface of the gelatin balls.

[0016] According to the method for preparing the core-shell structure magnetic robot of the present invention, the method for preparing the sodium alginate solution is as follows:

[0017] Sodium alginate powder was mixed with deionized water and stirred in a magnetic stirrer at 40 degrees Celsius until completely melted to obtain a 2% wt sodium alginate solution.

[0018] According to the preparation method of the core-shell structure magnetic robot of the present invention, the adjustable uniform magnetic field is provided by a magnetic field generating device; the magnetic field generating device adjusts the magnetic field intensity of the adjustable uniform magnetic field by adjusting the distance between two cylindrical permanent magnets; and the melted gelatin balls are cooled and shaped by a correspondingly arranged cooling unit to obtain the final magnetic robot with a core-shell structure.

[0019] According to the method for preparing the core-shell structure magnetic robot of the present invention, the magnetic field generating device includes two positioning base plates, two permanent magnet mounting units and a magnetic robot placement bracket.

[0020] The two positioning base plates are provided with slideways along their lengths and are placed opposite to each other; the magnetic robot mounting bracket is connected between the two positioning base plates and is connected to corresponding positions in the middle sections of the two positioning base plates; the two permanent magnet mounting units are connected between the two positioning base plates and are arranged on both sides of the magnetic robot mounting bracket; the permanent magnet mounting units are slidably connected to the two positioning base plates;

[0021] A culture dish is placed in the middle of the magnetic robot placement bracket for placing the magnetic robot; a cooling unit is set below the corresponding position of the culture dish.

[0022] According to the method for preparing the core-shell structure magnetic robot of the present invention, the permanent magnet mounting unit includes a base, a top cover, an inner baffle and an outer baffle.

[0023] The two bottom ends of the base are slidably connected to the two positioning base plates and fixed by screws and nuts; the top cover is fixed to the base by screws and nuts, and a cavity is formed between the top cover and the base. The inner baffle and the outer baffle form an encapsulation structure in the cavity for encapsulating the cylindrical permanent magnet.

[0024] According to the preparation method of the core-shell structure magnetic robot of the present invention, the magnetic robot placement bracket has a structure with high ends and low middle along the spanning direction, the middle low section is used to place the culture dish, and the high ends are used to form a limit for the culture dish; the bottom of the middle low section serves as a cooling unit for placing a cooling component to cool and shape the gelatin balls in a melted state of the magnetic robot; the height of the middle low section makes the magnetic robot in the culture dish between two cylindrical permanent magnets.

[0025] Beneficial effects of the present invention: The magnetic robot of the method of the present invention is prepared based on biocompatible and degradable hydrogel materials, and has a core-shell structure. The directional assembly of magnetic particles inside the robot is completed by applying a directional magnetic field externally, that is, the magnetic particles are assembled into a chain structure by adjusting the adjustable magnetic field, which can realize flexible control of the robot's maximum movement speed.

[0026] The method of the present invention utilizes the inherent properties of calcium alginate and gelatin hydrogel to prepare a robot with a core-shell structure and magnetic particles inside. The direction of the magnetic particles in the robot core is controlled by an external magnetic field to obtain a chain structure of the magnetic particles. Based on the requirements for the robot's motion performance, external magnetic fields of different intensities are used to flexibly control the robot's maximum motion speed.

[0027] The robot prepared by the method of the present invention is biodegradable, has low cost, simple process, and is suitable for mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a flow chart of the method for preparing the core-shell structure magnetic robot of the present invention;

[0029] Figure 2 is a schematic diagram of a gelatin ball;

[0030] Figure 3 is a schematic diagram of the formation of a calcium alginate shell;

[0031] Figure 4 This is a schematic diagram of the initial magnetic robot;

[0032] Figure 5 This is a schematic diagram of the initial magnetic robot after heating;

[0033] Figure 6 This is a schematic diagram of the final magnetic robot with a core-shell structure;

[0034] Figure 7 is a schematic diagram of a magnetic field generating device;

[0035] Figure 8 This is a schematic diagram of the preparation process of the initial magnetic robot with a core-shell structure;

[0036] Figure 9 This is a schematic diagram of the directional assembly process of magnetic particles inside the initial magnetic robot. DETAILED DESCRIPTION

[0037] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0038] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0039] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but they are not intended to limit the present invention.

[0040] Specific implementation method 1. Combination Figures 1 to 9 As shown, the present invention provides a method for preparing a core-shell structure magnetic robot, comprising:

[0041] The gelatin solution and the calcium chloride solution are uniformly mixed in a ratio of 3:1, and then uniformly mixed with 20 nm ferroferric oxide particles in a ratio of 5% to 10% by mass to obtain a magnetic mixed solution;

[0042] Combine Figure 2 、 Figure 3 and Figure 8 As shown, a droplet of the magnetic mixture is cooled in a culture dish containing liquid paraffin oil at 4 degrees Celsius and allowed to stand for a while to form a gelatin ball with magnetic particles; the paraffin oil on the surface of the gelatin ball is cleaned, and the ball is immersed in a sodium alginate solution for at least 10 seconds and then removed to form a calcium alginate shell; thus, an initial magnetic robot with a core-shell structure is obtained; the sodium alginate solution is a 2% wt sodium alginate solution;

[0043] Combine Figures 4 to 6 and Figure 9As shown, the initial magnetic robot is heated to melt all the gelatin balls in its core, and the magnetic particles therein are assembled in a chain-like direction in an adjustable uniform magnetic field. The robot is then cooled and shaped until the gelatin in the core is completely solidified. The solidification of the core gelatin finalizes the assembly of the magnetic particles, and finally the final magnetic robot with a core-shell structure is obtained.

[0044] This embodiment utilizes the inherent properties of calcium alginate and gelatin hydrogel to fabricate a core-shell robot. Heating the robot melts the gelatin core. Placing the robot in an adjustable magnetic field generator allows for the chain-like, directional assembly of the core magnetic particles and subsequent cooling of the robot to stabilize its shape.

[0045] Furthermore, the preparation method of the gelatin solution is:

[0046] The gelatin particles were mixed with deionized water and stirred in a magnetic stirrer at 45 degrees Celsius until completely melted to obtain a 10% wt gelatin solution.

[0047] The preparation method of calcium chloride solution is:

[0048] Anhydrous calcium chloride particles were mixed with deionized water and stirred in a magnetic stirrer at room temperature until completely melted to obtain a 1% wt calcium chloride solution.

[0049] In this embodiment, a needle is used to extract the magnetic mixed liquid, and a simple extrusion method is used to obtain magnetic mixed liquid droplets, which are dropped into a culture dish containing liquid paraffin at 4 degrees Celsius. After the droplets cool, gelatin balls with magnetic particles are formed.

[0050] A simple extrusion method can prepare a large number of gelatin spheres in a short period of time, and shell preparation and directed assembly of magnetic particles can be performed simultaneously on a large number of robots.

[0051] Use tweezers to remove the gelatin balls from the liquid paraffin, and repeatedly wash the gelatin balls with water and anhydrous ethanol to remove the paraffin oil on the surface of the gelatin balls.

[0052] The preparation method of sodium alginate solution is as follows:

[0053] Sodium alginate powder was mixed with deionized water and stirred in a magnetic stirrer at 40 degrees Celsius until completely melted to obtain a 2% wt sodium alginate solution.

[0054] Going further, combined Figure 7 As shown, the adjustable uniform magnetic field is provided by a magnetic field generating device; the magnetic field generating device adjusts the magnetic field strength of the adjustable uniform magnetic field by adjusting the distance between two cylindrical permanent magnets; and the melted gelatin balls are cooled and shaped by a correspondingly arranged cooling unit to obtain the final magnetic robot with a core-shell structure.

[0055] The magnetic field generating device includes two positioning base plates 1-1, two permanent magnet mounting units 1-3 and a magnetic robot placement bracket 1-2.

[0056] The two positioning base plates 1-1 each have a slide along its length and are placed opposite to each other; a magnetic robot placement bracket 1-2 is connected between the two positioning base plates 1-1 and is connected to corresponding positions in the middle sections of the two positioning base plates 1-1; two permanent magnet mounting units 1-3 are connected between the two positioning base plates 1-1 and are arranged on both sides of the magnetic robot placement bracket 1-2; the permanent magnet mounting units 1-3 are slidably connected to the two positioning base plates 1-1;

[0057] A culture dish is placed in the middle of the magnetic robot placement bracket 1-2 for placing the magnetic robot; a cooling unit is set below the corresponding position of the culture dish.

[0058] The permanent magnet mounting unit 1-3 includes a base 1-31, a top cover 1-32, an inner baffle 1-33 and an outer baffle 1-34.

[0059] The two bottom ends of the base 1-31 are slidably connected to the two positioning base plates 1-1 and fixed by screws and nuts; the top cover 1-32 is fixed to the base 1-31 by screws and nuts, and a cavity is formed between the top cover 1-32 and the base 1-31, and the inner baffle 1-33 and the outer baffle 1-34 form a packaging structure in the cavity for encapsulating the cylindrical permanent magnet.

[0060] The positioning base plate 1-1 is provided with mounting holes for securing the base 1-31 with screws and nuts. The base 1-31 can slide along the positioning base plate 1-1, enabling the relative position of the permanent magnets to be adjusted to a desired distance, thereby enabling the magnetic field strength to be adjusted. The inner baffle 1-33 and the outer baffle 1-34 can be connected via screws and nuts.

[0061] The magnetic robot placement bracket 1-2 has a structure with high ends and low middle along the span direction. The low middle section is used to place the culture dish, and the high ends are used to limit the culture dish; the bottom of the low middle section serves as a cooling unit for placing cooling parts to cool and shape the gelatin balls in the melted state of the magnetic robot; the height of the low middle section makes the magnetic robot in the culture dish between two cylindrical permanent magnets.

[0062] The cooling element may be an ice cube, which cools the robot and thereby achieves finalization of the directional assembly of the magnetic particles.

[0063] Although the present invention is described herein with reference to specific embodiments, it should be understood that these embodiments are merely illustrative of the principles and applications of the invention. It should be understood that many modifications may be made to the illustrative embodiments, and that other arrangements may be devised, without departing from the spirit and scope of the invention as defined by the appended claims. It should be understood that the various dependent claims and features described herein may be combined in ways other than those described in the original claims. It should also be understood that features described in conjunction with individual embodiments may be used in conjunction with other described embodiments.

Claims

1. A method for preparing a core-shell structure magnetic robot, characterized in that: include: The gelatin solution and the calcium chloride solution are uniformly mixed in a ratio of 3:1, and then uniformly mixed with 20 nm ferroferric oxide particles in a ratio of 5% to 10% by mass to obtain a magnetic mixed solution; The magnetic mixture droplets were cooled in a petri dish containing 4-degree Celsius liquid paraffin oil to form gelatin spheres with magnetic particles. The paraffin oil on the surface of the gelatin spheres was cleaned and then immersed in a sodium alginate solution for at least 10 seconds before being removed to form a calcium alginate shell, thereby obtaining an initial magnetic robot with a core-shell structure. The initial magnetic robot is heated to melt its gelatin balls, and the magnetic particles therein are assembled in a chain-like manner in an adjustable uniform magnetic field. The robot is then cooled and shaped to obtain the final magnetic robot with a core-shell structure.

2. The method for preparing a core-shell structure magnetic robot according to claim 1, characterized in that: The preparation method of the gelatin solution is: The gelatin particles were mixed with deionized water and stirred in a magnetic stirrer at 45 degrees Celsius until completely melted to obtain a 10% wt gelatin solution.

3. The method for preparing a core-shell structure magnetic robot according to claim 1, characterized in that: The preparation method of calcium chloride solution is: Anhydrous calcium chloride particles were mixed with deionized water and stirred in a magnetic stirrer at room temperature until completely melted to obtain a 1% wt calcium chloride solution.

4. The method for preparing a core-shell structure magnetic robot according to claim 1, characterized in that: The magnetic mixed liquid is extracted by a needle, and the magnetic mixed liquid droplets are obtained by an extrusion method.

5. The method for preparing a core-shell structure magnetic robot according to claim 1, characterized in that: The gelatin balls were repeatedly washed with water and anhydrous ethanol to remove the paraffin oil on the surface of the gelatin balls.

6. The method for preparing a core-shell structure magnetic robot according to claim 1, characterized in that: The preparation method of sodium alginate solution is as follows: Sodium alginate powder was mixed with deionized water and stirred in a magnetic stirrer at 40 degrees Celsius until completely melted to obtain a 2% wt sodium alginate solution.

7. The method for preparing a core-shell structure magnetic robot according to claim 1, characterized in that: The adjustable uniform magnetic field is provided by a magnetic field generating device; the magnetic field generating device adjusts the magnetic field intensity of the adjustable uniform magnetic field by adjusting the distance between two cylindrical permanent magnets; and the melted gelatin balls are cooled and shaped by a correspondingly arranged cooling unit to obtain the final magnetic robot with a core-shell structure.

8. The method for preparing a core-shell structure magnetic robot according to claim 7, characterized in that: The magnetic field generating device comprises two positioning base plates (1-1), two permanent magnet mounting units (1-3) and a magnetic robot placement bracket (1-2). The two positioning base plates (1-1) are respectively provided with slideways along the length direction and are placed opposite to each other; the magnetic robot placement bracket (1-2) is connected between the two positioning base plates (1-1) and is connected to corresponding positions in the middle sections of the two positioning base plates (1-1); the two permanent magnet installation units (1-3) are connected between the two positioning base plates (1-1) and are arranged on both sides of the magnetic robot placement bracket (1-2); the permanent magnet installation units (1-3) are slidably connected to the two positioning base plates (1-1); A culture dish is placed in the middle of the magnetic robot placement bracket (1-2) for placing the magnetic robot; a cooling unit is arranged below the corresponding position of the culture dish.

9. The method for preparing a core-shell structure magnetic robot according to claim 8, characterized in that: The permanent magnet mounting unit (1-3) comprises a base (1-31), a top cover (1-32), an inner baffle (1-33) and an outer baffle (1-34). The two bottom ends of the base (1-31) are slidably connected to the two positioning base plates (1-1) and fixed by screws and nuts; the top cover (1-32) is fixed to the base (1-31) by screws and nuts, and forms a cavity between the top cover and the base (1-31); the inner baffle (1-33) and the outer baffle (1-34) form a packaging structure in the cavity for packaging the cylindrical permanent magnet.

10. The method for preparing a core-shell structure magnetic robot according to claim 9, characterized in that: The magnetic robot placement bracket (1-2) has a structure with high ends and a low middle along the span direction, wherein the low middle section is used for placing a culture dish, and the high ends are used for forming a limit for the culture dish; the lower part of the low middle section serves as a cooling unit for placing a cooling component to cool and shape the gelatin ball in a melted state of the magnetic robot; and the height of the low middle section enables the magnetic robot in the culture dish to be located between two cylindrical permanent magnets.

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