Magnetic conducting wire and preparation method and application thereof

Abstract

The invention discloses a magnetic conducting wire and a preparation method and application thereof. The magnetic conducting wire comprises a core wire, wherein the core wire is provided with a first tail end and a second tail end which are oppositely arranged; and the magnetic navigation assembly comprises a first annular magnet, a second annular magnet and a magnetic fluid coating layer, the first annular magnet and the second annular magnet are arranged at the first tail end in a spaced and sleeving manner and define a spacer region, and the magnetic fluid coating layer coats the spacer region. The magnetic conducting wire provided by the embodiment of the invention at least has the following beneficial effects that compared with a common magnetic conducting wire, the magnetic conducting wire of the structure provided by the invention utilizes the annular magnets which generate higher axial magnetic efficiency under the same volume, and meanwhile, the magnetic fluid coating layer is matched between the two annular magnets, so that the magnetism of the conducting wire is increased, and the magnetic conducting wire is more stable in magnetic conduction. And the structure instability caused by the combination of heterogeneous materials is reduced, so that the magnetic conducting wire which is higher in magnetic response capability, tighter, firmer, flexible and controllable is obtained.

Description

Technical Field

[0001] The present application relates to the field of medical device technology, and in particular to magnetic conductive wires and preparation methods and applications thereof. Background Art

[0002] The medical guidewire used in interventional surgery is a key medical device, usually made of materials such as stainless steel and polymers. It has high strength, flexibility and biocompatibility. It is used to provide support, guidance and positioning during interventional surgery, and to guide other instruments (such as catheters, stents, ablators, etc.) into the target area. The design of the guidewire includes different diameters, lengths, curvatures and tip shapes to adapt to different surgical needs and anatomical structures. Modern guidewires use advanced materials and improved designs, have better flexibility, and can smoothly pass through complex vascular pathways. They are also subject to rigorous biocompatibility testing to ensure that they will not cause adverse reactions when used in the body.

[0003] The development of magnetically controlled guidewires stems primarily from the need for precise control of medical guidewires during clinical surgery and the reduction of radiation exposure during interventional procedures. When treating complex, narrow or tortuous lesions, traditional medical guidewires struggle to navigate narrow lumens, necessitating more precise guidewire control technology. Furthermore, the use of X-rays to position guidewires during traditional interventional procedures inevitably exposes both patients and medical staff to radiation exposure. Replacing traditional medical guidewires with magnetically controlled guidewires reduces direct contact between doctors and patients, improves guidewire control accuracy, and accelerates surgical procedures, thereby reducing patients' radiation exposure.

[0004] At present, magnetic field navigation technology mainly uses electromagnets or permanent magnets to generate a controllable magnetic field, and integrates magnetic components into the guide wire at the same time, and uses the external controllable magnetic field to achieve precise guidance of the guide wire, thereby realizing non-contact control. For example, there is a soft magnetic guide wire, which is made by mixing ferromagnetic powder and high molecular polymer in a certain proportion to form a ferromagnetic gel and adding a wrapping layer to reduce friction. However, the magnetism provided by the magnetic powder in this soft magnetic guide wire is limited. Based on the normal size of the guide wire, even if it is magnetized to the maximum extent, there is still a situation where the guide wire is insufficiently magnetic. If the guide wire cannot be deflected normally during surgery due to insufficient magnetism, it will greatly affect the progress of the operation.

[0005] There is also a medical magnetically controlled deformable guidewire that uses PDMS as a liquid medium and adds a large number of magnetic beads to the head to provide magnetism. Although this guidewire has good flexibility and a larger bending angle, the magnetic beads added to the guidewire will slip and fall off due to the low hardness and low stability of the medium material itself. On the other hand, the increase in the volume of the magnetic beads will affect the filling amount of the magnetic fluid, and it is very easy to break due to too little magnetic fluid in certain cross-sections. This is a very serious problem during surgery. Therefore, it is necessary to provide a magnetic guidewire with high magnetic response performance and good structural stability. Summary of the Invention

[0006] The present application aims to solve at least one of the technical problems existing in the prior art. To this end, the present application proposes a magnetic conductive wire and a preparation method and application thereof.

[0007] In a first aspect of the present application, a magnetic conductive wire is provided, comprising:

[0008] a core wire having a first end and a second end disposed opposite to each other;

[0009] The magnetic navigation component includes a first annular magnet, a second annular magnet and a magnetic fluid coating layer. The first annular magnet and the second annular magnet are spaced apart and sleeved at the first end to define a spacing area, and the magnetic fluid coating layer is coated on the spacing area.

[0010] The magnetic conductive wire according to the embodiment of the present application has at least the following beneficial effects:

[0011] Compared with conventional magnetic wires, the magnetic wire of this structure provided in the present application utilizes annular magnets with higher axial magnetic efficiency under the same volume, and at the same time, a magnetic fluid coating layer is matched between the two annular magnets. This not only increases the magnetism of the wire, but also reduces the structural instability caused by the combination of heterogeneous materials, thereby obtaining a magnetic wire with higher magnetic response ability, which is tighter, stronger, more flexible and controllable.

[0012] In some embodiments of the present application, the raw materials of the magnetic fluid coating layer include magnetic powder and a polymer matrix material.

[0013] In some embodiments of the present application, the mass ratio of the magnetic powder to the polymer matrix material is 1:(0.5-2).

[0014] In some embodiments of the present application, the average particle size of the magnetic powder is less than 10 microns.

[0015] In some embodiments of the present application, the Shore A hardness of the polymer matrix material is 90 or less.

[0016] In some embodiments of the present application, the polymer matrix material includes at least one of thermoplastic polyurethane elastomer and silicone.

[0017] In some embodiments of the present application, the lengths of the first annular magnet and the second annular magnet are independently 2 to 4 mm.

[0018] In a second aspect of the present application, a method for preparing the aforementioned magnetic conductive wire is provided, the method comprising the following steps:

[0019] Taking the guide wire with the first end of the core wire exposed;

[0020] A first annular magnet and a second annular magnet are sleeved on the first end, and magnetic ink is covered on the interval area to form a magnetic fluid coating layer after solidification.

[0021] In a third aspect of the present application, a catheter is provided, comprising any one of the aforementioned magnetic conductive wires.

[0022] In a fourth aspect of the present application, a medical device is provided, which comprises any one of the aforementioned magnetic guide wires or any one of the aforementioned catheters.

[0023] In a fifth aspect of the present application, a method for controlling a magnetic guide wire is provided, the method comprising the following steps A1 and A2:

[0024] A1: Deliver the magnetic guide wire from the first end to the destination pipeline;

[0025] A2: The bending deformation of the first end is controlled by an external magnetic field to adjust the movement direction of the magnetic wire, and the second end is clamped by an external transmission device to control the forward or backward movement of the magnetic wire.

[0026] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become obvious from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a structural cross-sectional view of a magnetic conductive wire in one embodiment of the present application.

[0028] Figure 2 This is a flow chart for preparing the magnetic conductive wire in Example 1 of the present application.

[0029] Figure 3 This is a schematic diagram of the fastening surface of the mold used in the preparation process of the magnetic conductive wire in Example 1 of the present application.

[0030] Figure 4 This is a schematic diagram of the preparation of magnetic conductive wire in Example 1 of the present application.

[0031] Figure 5 This is a comparison of the magnetic response capabilities of the magnetic conductive wires made of ring magnets of different lengths in the control variable experiment 1 of this application. Among them, A to D are the results of the magnetic conductive wires made of ring magnets with lengths of 1mm, 2mm, 3mm, and 4mm, respectively.

[0032] Figure 6 This is a comparison of the magnetic response capabilities of the magnetic wires made of different mass percentages of magnetic fluid in the control variable experiment 2 of this application. Among them, A to C are the results of the magnetic wires made of magnetic fluid with a mass percentage of 30%, 40%, and 50% NdFeB, respectively.

[0033] Reference numerals: first end 111 , second end 112 , outer shell 120 , protective layer 130 , first annular magnet 141 , second annular magnet 142 , magnetic fluid coating 150 , coating 160 . DETAILED DESCRIPTION

[0034] The following will clearly and completely describe the concept and technical effects of this application in conjunction with the embodiments to fully understand the purpose, features and effects of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments of this application, other embodiments obtained by those skilled in the art without creative work are all within the scope of protection of this application.

[0035] The embodiments of the present application are described in detail below. The described embodiments are exemplary and are only used to explain the present application, and should not be understood as limiting the present application.

[0036] In the description of this application, "several" means more than one, "plurality" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. The use of "first" and "second" in the description is solely for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0037] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by those skilled in the art to which this application belongs. The terms used herein are for the purpose of describing the embodiments of this application only and are not intended to limit this application. The specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0038] In a first aspect of the present application, a magnetic conductive wire is provided.

[0039] The term "guidewire" refers to an interventional medical device that typically passes through various cavities (such as the blood vessels, urinary tract, and digestive tract) to guide therapeutic devices such as catheters, balloons, and stents to their designated locations, providing support and guidance for the procedure. Correspondingly, a magnetic guidewire refers to a guidewire that uses the principle of magnetic control to guide and position itself through various cavities.

[0040] refer to Figure 1The magnetic conductive wire includes a core wire having a first end 111 and a second end 112 arranged opposite to each other. The magnetic conductive wire also includes a magnetic navigation assembly, which includes a first annular magnet 141, a second annular magnet 142 and a magnetic fluid coating 150. The first annular magnet 141 and the second annular magnet 142 are respectively sleeved on the first end 111 of the core wire, and are spaced apart from each other to define a spacing area between the sleeve positions of the first annular magnet 141 and the second annular magnet 142 at the first end 111, and the magnetic fluid coating 150 is also coated on the spacing area, thereby finally forming an outer layer structure composed of the first annular magnet 141, the magnetic fluid coating 150 and the second annular magnet 142 in sequence on the first end 111 of the core wire.

[0041] Compared to conventional magnetic guide wires, the magnetic guide wire structure provided by this application utilizes annular magnets with higher axial magnetic efficiency under the same volume, and at the same time, a magnetic fluid coating layer is placed between the two annular magnets. This not only increases the magnetic properties of the guide wire, but also reduces the structural instability caused by the combination of heterogeneous materials, thereby obtaining a magnetic guide wire with higher magnetic response capability, a tighter and stronger structure, and flexible controllability. Among them, the magnetic efficiency is affected by the size of the volume to surface area. At the same time, in order to ensure the cross-sectional consistency of the guide wire, a hollow cylindrical magnet, i.e., an annular magnet, is selected to maximize its axial magnetic efficiency.

[0042] In some embodiments, the magnetic fluid coating is a flexible magnetic fluid coating.

[0043] In some embodiments, the raw materials of the magnetic fluid coating layer include magnetic powder and a polymer matrix material.

[0044] In some embodiments, the magnetic powder is a hard magnetic material, which has a higher coercive force (Hc) and stronger remanence than soft magnetic materials. In some embodiments, the hard magnetic material includes at least one of NdFeB, SmCo, AlNiCo, and ferrite. In some embodiments, the hard magnetic material includes NdFeB, and the maximum magnetic energy product (BHmax) of NdFeB can reach hundreds of kJ / m. 3, which makes it possible to generate a stronger magnetic field than other types of magnets (such as alnico and ferrite) in the case of the same volume; and NdFeB also has high coercivity and can maintain strong magnetism after removing the external magnetic field. In some embodiments, the particle size of the magnetic powder is less than 100 microns, for example, it can be 50 microns, 40 microns, 30 microns, 20 microns, 15 microns, 10 microns, 9 microns, 8 microns, 7 microns, 6 microns, 5 microns, 4 microns, 3 microns, 2 microns, 1 micron, 900 nanometers, 800 nanometers, 700 nanometers, 600 nanometers, 500 nanometers, 400 nanometers, 300 nanometers, 200 nanometers, 100 nanometers, 50 nanometers, 30 nanometers, 20 nanometers, 10 nanometers. The smaller the particle size of the magnetic powder, the higher the mixing efficiency when mixed with the polymer matrix material, thereby achieving a stronger magnetic response capability. The particle size of magnetic powder refers to the particle size expressed in diameter. For spherical particles, the particle size is the particle diameter; for irregular particles, the particle size is generally the particle's equivalent diameter, such as the volume equivalent diameter, projected area diameter, or any other type. In some embodiments, the particle size refers to the maximum particle size, i.e., the minimum standard sieve size at which the sieve pass rate is 100%.

[0045] In some embodiments, the polymer matrix material includes at least one of thermoplastic polyurethane (TPU) and silicone. In order to achieve flexible steering of the guidewire, the polymer matrix material needs to meet certain hardness requirements. In some embodiments, the Shore A hardness of the polymer matrix material is below 90, for example, it can be 88, 86, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, or 30. In some embodiments, the Shore A hardness of the polymer matrix material is 30 to 90.

[0046] In some embodiments, the mass ratio of magnetic powder to polymer matrix material in the magnetic fluid coating layer is 1:(0.5-2), for example, it can be 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9, 1:2.

[0047] In some embodiments, at least one of the first annular magnet 141 and the second annular magnet 142 is a magnet made of a hard magnetic material. In some embodiments, the hard magnetic material includes at least one of NdFeB, SmCo, AlNiCo, and ferrite. In some embodiments, the first annular magnet 141 and the second annular magnet 142 are NdFeB magnets.

[0048] In some embodiments, reference Figure 1The length l1 of the first annular magnet 141 and the length l2 of the second annular magnet 142 are independently 2 to 4 mm, for example, 2 mm, 2.5 mm, 3 mm, 3.5 mm, or 4 mm. The annular magnet lengths within this range effectively balance the guidewire's steering ability and magnetic response. If the length is too long, the guidewire's tip will gradually become too rigid and difficult to steer. If the length is too short, the magnetic response will gradually weaken.

[0049] In some embodiments, reference Figure 1 The coating length l3 of the magnetic fluid coating is 1 to 5 mm, for example, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, or 5 mm. In some embodiments, the length l1 of the first annular magnet 141 is the same as the length l2 of the second annular magnet 142. In some embodiments, the length l1 of the first annular magnet 141 is greater than the length l2 of the second annular magnet 142. In some embodiments, the length l1 of the first annular magnet 141 is less than the length l2 of the second annular magnet 142.

[0050] In some embodiments, reference Figure 1 The outer diameter d1 of the first annular magnet 141 and the outer diameter d2 of the second annular magnet 142 are independently 0.2 to 1 mm, for example, they can be 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.36 mm, 0.4 mm, 0.45 mm, 0.46 mm, 0.5 mm, 0.53 mm, 0.55 mm, 0.6 mm, 0.64 mm, 0.65 mm, 0.7 mm, 0.75 mm, 0.8 mm, 0.85 mm, 0.9 mm, 0.95 mm, 0.97 mm, 0.98 mm, 0.99 mm, and 1 mm. In some embodiments, the outer diameter d1 of the first annular magnet 141 is the same as the outer diameter d2 of the second annular magnet 142; in some embodiments, the outer diameter d1 of the first annular magnet 141 is larger than the outer diameter d2 of the second annular magnet 142; in some embodiments, the outer diameter d1 of the first annular magnet 141 is smaller than the outer diameter d2 of the second annular magnet 142.

[0051] In some embodiments, the core wire has a tendency to gradually decrease in diameter in a direction away from the second end 112 at the first end 111. In some embodiments, the first end 111 of the core wire further has an outer jacket 120. In some embodiments, the outer jacket 120 extends from the first end 111 of the core wire to the second end 112. In some embodiments, the outer jacket 120 is provided along the entire core wire from the first end 111 to the second end 112. Thus, in some embodiments, the second annular magnet 142 in the magnetic navigation assembly is sleeved on the outer jacket 120. In some embodiments, the first annular magnet 141 and the second annular magnet 142 in the magnetic navigation assembly are both sleeved on the outer jacket 120. In some embodiments, a magnetic fluid coating 150 is coated on the core wire in the spacer. In some embodiments, the magnetic fluid coating 150 is coated on the outer jacket 120 in the spacer. It is understood that the inner diameters of the first and second annular magnets 141, 142 are substantially the same as the diameter of the core wire. For example, the inner diameters of the first and second annular magnets 141, 142 can be the same as the diameter of the core wire, or the inner diameters of the first and second annular magnets 141, 142 can independently differ from the diameter of the core wire by ±0.05mm, ±0.04mm, ±0.03mm, ±0.02mm, or ±0.01mm, respectively. In some embodiments, the inner diameters of the first and second annular magnets 141, 142 are independently greater than the diameter of the core wire by within 0.05mm, 0.04mm, 0.03mm, 0.02mm, or 0.01mm, respectively. It is understood that the difference between the two should be as small as possible to ensure the coaxiality of the annular magnets and the core wire, thereby controlling the symmetry of the final magnetic conductive wire and providing flexibility and accuracy in control. In some embodiments, the core wire is a metal wire. In some embodiments, the metal wire is a metal wire made of a single substance, a mixture, or an alloy of at least one metal element among copper, silver, titanium, and nickel. In some embodiments, the metal wire is any one of nickel-titanium alloy, copper, silver, and titanium alloy. In some embodiments, the outer layer is a metal layer or a polymer layer. In some embodiments, the metal layer is a metal layer made of a single substance, a mixture, or an alloy of at least one metal element among iron, copper, silver, titanium, and nickel. In some embodiments, the metal layer is a metal layer formed by any one of nickel-titanium alloy, iron alloy, copper, silver, and titanium alloy. In some embodiments, the metal layer is a metal layer formed by winding a metal wire (nickel-titanium alloy, iron alloy, copper, silver, and titanium alloy).

[0052] In some embodiments, reference Figure 1The magnetic guide wire further includes a protective layer 130 covering the core wire. In some embodiments, the protective layer 130 is a polymer layer. In some embodiments, the protective layer 130 is a polytetrafluoroethylene layer. In some embodiments, the protective layer 130 and the magnetic navigation assembly are located at different positions on the surface of the core wire. In some embodiments, the protective layer 130 and the magnetic navigation assembly are spaced apart on the surface of the core wire.

[0053] In some embodiments, the first end of the core wire is straight or bent. In some embodiments, the bend includes a J-shape. In some embodiments, the bend angle is 5 to 175 degrees, for example, 5 degrees, 10 degrees, 15 degrees, 20 degrees, 25 degrees, 30 degrees, 35 degrees, 40 degrees, 45 degrees, 50 degrees, 55 degrees, 60 degrees, 65 degrees, 70 degrees, 75 degrees, 80 degrees, 85 degrees, 90 degrees, 95 degrees, 100 degrees, 105 degrees, 110 degrees, 115 degrees, 120 degrees, 125 degrees, 130 degrees, 135 degrees, 140 degrees, 145 degrees, 150 degrees, 155 degrees, 160 degrees, 165 degrees, 170 degrees, or 175 degrees. It will be understood that the bend angle is the angle at which the bent portion deviates from the extension line of the unbent portion.

[0054] In some embodiments, the magnetic guide wire further includes a coating 160 that encapsulates the magnetic navigation assembly. In some embodiments, coating 160 can be either a hydrophobic coating or a hydrophilic coating. In some embodiments, coating 160 can also be an anticoagulant coating, an antibacterial coating, or a coating that combines multiple of these functions. This coating treatment not only enhances biocompatibility and reduces friction in the magnetic guide wire robot, but also further prevents magnet detachment and magnetic ink leakage, thereby increasing the safety of the guide wire.

[0055] In a second aspect of the present application, a method for preparing a magnetic conductive wire is provided, the method comprising the following steps:

[0056] Taking the guide wire with the first end of the core wire exposed;

[0057] A first annular magnet and a second annular magnet are sleeved on the first end, and magnetic ink is covered on the interval area to form a magnetic fluid coating layer after solidification.

[0058] In some embodiments, the method for exposing the first end of the core wire of the guide wire is to peel off the local protective layer coated on the first end of the guide wire, thereby exposing the first end of the core wire coated therein. It is understood that the guide wire with the first end of the core wire exposed can also be prepared from scratch.

[0059] In some embodiments, the first annular magnet and the second annular magnet are respectively obtained by punching a cylindrical magnet. In some embodiments, the punching method includes at least one of electric spark punching, ultrasonic punching, laser punching, and electromagnetic pulse punching. The punching process avoids the possibility of the magnet falling off the guide wire. The structural proportion of heterogeneous materials (including core wire and magnetic fluid coating, etc.) is reduced, the overall physical stability of the guide wire is enhanced, and the correctness of the magnet placement direction is also guaranteed to a certain extent.

[0060] In some embodiments, the first and second annular magnets further undergo a post-processing step after being punched. In some embodiments, the post-processing step includes surface treatment. In some embodiments, the surface treatment includes forming a protective layer on the first and second annular magnets. In some embodiments, the protective layer is a biocompatible protective layer and can be formed from a biocompatible material commonly used in medical devices, thereby enhancing the biocompatibility of the magnetic guide wire. It can also prevent corrosion and rusting of the magnets, improving their magnetic response and product life.

[0061] In some embodiments, coating the spacer with magnetic ink and forming a magnetic fluid coating after curing includes placing the spacer of the guidewire into a corresponding position within a mold cavity, filling the cavity with magnetic ink, closing the mold so that the magnetic ink surrounds the spacer, and allowing the magnetic ink to cure to form the magnetic fluid coating. By designing a dedicated mold, the shape of the guidewire is retained, ensuring easy guidewire steering and ensuring that the core of the guidewire is located at the axis after curing, thereby improving mechanical properties.

[0062] It is understandable that the magnetic fluid in the magnetic fluid coating layer only means that the raw material of the coating layer is in a fluid state, rather than the coating layer formed in the end being in a fluid state. In fact, the magnetic fluid coating layer formed in the end is in a deformable solid state.

[0063] In some embodiments, the method for preparing the magnetic guide wire further includes forming a coating covering the magnetic navigation component after forming the magnetic fluid coating layer. In some embodiments, the coating formation method includes but is not limited to at least one of dip coating, spray coating, spin coating, blade coating, and electrophoretic coating.

[0064] In a third aspect of the present application, a catheter is provided, comprising any one of the aforementioned magnetic conductive wires.

[0065] In a fourth aspect of the present application, a medical device is provided, which comprises any one of the aforementioned magnetic guide wires or any one of the aforementioned catheters.

[0066] In some embodiments, the medical device can be a single implant, biopsy needle, puncture needle, cannula, ablator, or the like.

[0067] In some embodiments, the medical device may also be a complex system, for example, including one or more modules such as a magnetic field generation module, a transmission module, an image display module, and a drug delivery module, thereby constituting a medical device system.

[0068] In a fifth aspect of the present application, a method for controlling a magnetic guide wire is provided, the method comprising the following steps:

[0069] A1: Deliver the magnetic guide wire from the first end to the destination pipeline;

[0070] A2: The bending deformation of the first end is controlled by an external magnetic field to adjust the movement direction of the magnetic wire, and the second end is clamped by an external transmission device to control the forward or backward movement of the magnetic wire.

[0071] In some embodiments, the direction of application of the external magnetic field forms a certain angle with the magnetization direction of the magnetic navigation assembly.

[0072] The present application is described below with reference to specific embodiments.

[0073] Example 1

[0074] This embodiment provides a magnetic navigation flexible robot (magnetic guide wire), and its preparation process is as follows: Figure 2 and Figure 4 , the specific steps are as follows:

[0075] S0. Preliminary processing of medical guide wire:

[0076] S0-0: Carefully cut off the curved tip of the medical guide wire.

[0077] S0-1: Carefully hold the 4cm long portion of the cut curved front end tightly and use a tool such as a fiber stripper to peel off the protective layer on the surface.

[0078] S0-2: Pay attention to the internal structure of the medical guidewire. The core is a nickel-titanium alloy wire, surrounded by a spirally wound stainless steel wire outer layer. After peeling off the outermost protective layer of the guidewire, the spiral stainless steel wire may become loose. In this case, it needs to be rewound and secured with a biocompatible material such as edible silicone.

[0079] S0-3: After cutting off the front end, the remaining part of the entire guide wire is straightened and clamped to wait for the front end of the subsequent processing. The preliminary processing of the medical guide wire is completed.

[0080] S1. Design and manufacture micro magnets

[0081] S1-0: Design a magnet based on the size of the medical guidewire. To maximize the magnet's volume by creating the smallest possible hole in the magnet, whose diameter is limited by the guidewire's size, the magnet's diameter was also chosen to be 1mm, given the 1mm diameter of the magnetic navigation robot. Experiments with controlled variables confirmed that a magnet with a length of 3mm exhibited the best steering performance after fabrication. Furthermore, since N52 NdFeB magnets are the most powerful magnets currently available, cylindrical N52 NdFeB magnets with a diameter of 1mm and a length of 3mm were selected for processing.

[0082] S1-1: Use electric spark drilling to drill a through hole with a diameter of 0.15mm on the cylindrical N52 NdFeB magnet.

[0083] S1-2: Magnet surface treatment: Epoxy resin coating is used to treat the surface of the punched magnets to enhance biocompatibility, prevent corrosion and rust, and improve their magnetic response and product life.

[0084] S2. Preparation of strong magnetic fluid

[0085] After weighing 10 grams of TPU using an electronic balance, the mixture was heated to 200 degrees Celsius in a small electric furnace. Once the TPU was molten, 10 grams of 5-micron NdFeB magnetic powder was added and stirred continuously to ensure thorough mixing, completing the preparation of the magnetic fluid. Gradient experiments confirmed that the NdFeB magnetic powder accounted for 50% of the magnetic fluid by weight.

[0086] S3. Design a mold and use it to shape and manufacture a magnetic navigation robot

[0087] S3-0: Design a shaping mold. To enhance the steering performance of the magnetic navigation robot, a mold is designed based on the common shape of medical loach guidewires. The mold consists of two parts: Figure 3 , which is a schematic diagram of the fastening surface of one of the molds. The overall length of the mold is 61mm, the width is 40mm, and the height is 20mm. There are four fixed rivet interfaces on the contact surface of the two molds for easy positioning and fixation. The four holes are all equilateral triangles with a side length of 6cm. There is also a semi-cylindrical groove with a diameter of 1mm on the mold. After the two molds are buckled, the grooves match to form a complete cylindrical cavity with a diameter of 1mm. The front end of the cavity is bent to one side to imitate the front end of the loach guide wire. One side of the bottom mold has a raised part to support the guide wire so that it enters the mold as straight as possible from the axis of the cylindrical groove. After mathematical calculation, the raised part at the bottom of the mold is 0.05mm higher than the groove of the mold body, so that the magnetic wire before and after processing presents a coaxial and co-centric effect (the axial and center positions are not offset).

[0088] S3-1: Insert the punched and processed magnet into the front end of the medical guide wire as the second ring magnet.

[0089] S3-2: Apply the prepared high-temperature magnetic fluid to the cylindrical grooves in the mold and scrape off the magnetic fluid adhering to other parts of the mold to prevent the appearance of unnecessary excess parts after solidification.

[0090] S3-3: Place the medical guidewire at the top of the semi-cylindrical groove, supported by the raised portion of the bottom mold. Adjust its position so that it is always centered in the groove and slightly press it into the magnetic fluid to secure it. Insert a second magnet at the front corner of the groove. The end of the medical guidewire's front end penetrates from one side of the magnet and remains on the inner wall of the magnet without exiting, forming a protrusion on the other side of the magnet, thereby enhancing the overall magnetic response capability of the magnetic navigation robot.

[0091] S3-4: Ensure the guidewire remains in place, then carefully apply approximately 1mm of magnetic fluid to the groove. Since the molten magnetic fluid is not very fluid and will not disperse immediately, any excess magnetic fluid residue must be cleaned.

[0092] S3-5: Align the top mold with the bottom mold to close the mold, adjust the position to align with the triangular prism interfaces at the four corners of the contact surface, and close them at once. Press hard to ensure that the magnetic fluid in the cylindrical groove is filled and the position of the medical guide wire remains unchanged.

[0093] S3-6: After cooling the mold to room temperature, observe the state of the magnetic fluid. After about 5 minutes, it can be observed that the magnetic fluid solidifies into a solid state with good toughness.

[0094] S3-7: Use the left and right handles provided on the mold to separate the top and bottom molds. During this step, work as vertically as possible, ensuring the contact surfaces of the two molds remain parallel during separation to minimize damage. After the mold is opened, a magnetic navigation robot with a front 4 cm covered in a hard magnetic composite material and containing two strong magnets is obtained. Use a scalpel or other tool to trim the front end as necessary to complete the preparation.

[0095] S4. Biocompatibility treatment

[0096] The sample was immersed in a PVP (polyvinyl pyrrolidone) polymer solution and then dried at 65°C for 8 hours to deposit PVP on the guidewire to complete the coating. This coating has good biocompatibility and chemical stability, and has good adhesion.

[0097] Comparative Example 1

[0098] This embodiment provides a magnetic guide wire, and its preparation process differs from that of Example 1 in that TPU is replaced with PDMS (polydimethylsiloxane) in the raw materials for preparing the magnetic fluid coating layer. At the same time, due to the high fluidity of PDMS, the medical guide wire is placed in a hose with an inner diameter of 1 mm, and then the magnetic fluid is injected into it. After heating at 50 degrees Celsius for 12 hours, the curing is completed. However, the flowing PDMS is also difficult to fix in the hose, and cavities appear after the curing is completed, and the quality of the coating is poor. In addition, the medical guide wire is difficult to keep on the axis of the hose. After curing, the position of the medical guide wire at each cross section of the magnetic navigation robot is unevenly distributed and is not always at the center of the circle, resulting in poor controllability.

[0099] Comparative Example 2

[0100] This embodiment provides a magnetic conductive filament, the preparation process of which differs from that of Example 1 in that the TPU in the raw material for the magnetic fluid coating is replaced with PDMS (thickened with 10 wt% nano-silica), and the mold shaping method of Example 1 and the thermal curing method of Comparative Example 1 are employed. The magnetic conductive filament obtained by this method has a hardened magnetic fluid coating due to the addition of the thickener, resulting in poor steering flexibility. Furthermore, the proportion of magnetic powder in the magnetic fluid coating decreases, weakening the magnetic response capability.

[0101] Comparative Example 3

[0102] This example provides a magnetic guidewire. Its preparation process differs from that of Example 1 in that the TPU used in the magnetic fluid coating is replaced with a photocurable material, which cures under light within a specific wavelength range. However, this method still fails to ensure that the medical guidewire remains at the geometric center of the navigation robot, resulting in poor mechanical properties.

[0103] Controlled variable experiment 1

[0104] Referring to Example 1, under the condition that all other variables are kept the same, cylindrical N52 NdFeB magnets with a diameter of 1mm and lengths of 1mm, 2mm, 3mm, and 4mm are selected in S1-0 for processing, respectively, to obtain first and second ring magnets with lengths of 1 to 4mm, respectively. The final magnetic guide wire is made using first and second ring magnets of different lengths. Then, a deflection experiment is conducted to compare the maximum steering angles under the application of the same magnetic field. The results are as follows: Figure 5As shown, when the length of the first and second ring magnets is 4mm, the guidewire tip is too rigid, resulting in poor steering flexibility under the influence of an external magnetic field. This is reflected in the increased difficulty in manipulating the different magnetic guidewires into lumens of the same diameter, and a visible "segmented" feeling when bending. This results in increased friction between the magnetic guidewire and the vessel wall when entering the blood vessel, increasing irritation to the vessel and reducing overall safety. When the length of the first and second ring magnets is 1mm or 2mm, the steering angle is relatively small due to the weak magnetic response.

[0105] Controlled Variable Experiment 2

[0106] Referring to Example 1, under the condition that all other variables are kept the same, the mass percentage of NdFeB magnetic powder in the preparation of S2 ferromagnetic fluid is 20%, 30%, 40%, 50%, 55%, and 60%, respectively, and magnetic wires with different magnetic powder mass gradient groups are prepared. Then, deflection experiments are carried out, and the maximum steering angles are compared by applying the same magnetic field. Some of the results are shown as follows. Figure 6 As shown in the figure, when the mass percentage of NdFeB magnetic powder in the magnetic fluid coating is 50%, the steering effect of the magnetic guide wire is the best, and this is the case for different lengths. In addition, when the mass percentage of NdFeB magnetic powder is 55% and 60%, the magnetic powder is not completely dispersed in the magnetic fluid, and the magnetic fluid coating shows a trend of increasing hardness.

[0107] In the above embodiments, for the material and production of the guide wire, components including medical loach guide wire, strong magnetic fluid, punched micro magnets and the like were used to control the guide wire diameter within 1 mm, and processes such as waterproof treatment of magnetic powder and lubrication treatment of the guide wire surface were carried out. By adding highly saturated magnetic powder fluid and individually designed micro magnets, the magnetic response ability of the guide wire was greatly enhanced, and then the mechanical properties of the guide wire were optimized by selecting the magnet embedding position optimized by mechanical model calculation. Through these two improvements and innovations, the system's ability to precisely control the magnetic guide wire and its flexibility of movement are improved. A highly biocompatible lubricating coating is also applied to the outside of the guide wire to reduce the friction of the guide wire in the blood vessel, improve the pushability of the guide wire while reducing the stimulation to the vascular tissue, reduce the physical burden on the patient, and enhance the safety of the system.

[0108] In summary, the present invention is innovative in terms of material properties, manufacturing process, guidewire matrix, etc., and is expected to improve the accuracy, safety and popularity of interventional surgery, reduce the radiation intake of doctors and patients during interventional surgery, reduce surgical costs, and improve the prognosis of interventional surgery. It can also provide a reference for scientific and technological research in other fields including magnetostatics and material mechanics.

[0109] The present application has been described in detail above with reference to the embodiments. However, the present application is not limited to the above embodiments. Various modifications can be made within the scope of knowledge possessed by a person skilled in the art without departing from the purpose of the present application. In addition, the embodiments of the present application and the features thereof can be combined with each other unless there is a conflict.

Claims

1. Magnetic conductive wire, characterized in that, include: a core wire having a first end and a second end disposed oppositely; The magnetic navigation component includes a first annular magnet, a second annular magnet and a magnetic fluid coating layer. The first annular magnet and the second annular magnet are spaced apart and arranged at the first end to define a spacing area. The magnetic fluid coating layer is coated on the spacing area.

2. The magnetic conductive wire according to claim 1, characterized in that The raw materials of the magnetic fluid coating layer include magnetic powder and polymer matrix material.

3. The magnetic conductive wire according to claim 2, characterized in that The mass ratio of the magnetic powder to the polymer matrix material is 1:(0.5-2).

4. The magnetic conductive wire according to claim 2, characterized in that The average particle size of the magnetic powder is less than 10 microns; and / or the Shore A hardness of the polymer matrix material is less than 90.

5. The magnetic conductive wire according to claim 2, characterized in that The polymer matrix material includes at least one of thermoplastic polyurethane elastomer and silicone.

6. The magnetic conductive wire according to claim 1, characterized in that The lengths of the first annular magnet and the second annular magnet are independently 2 to 4 mm.

7. The method for preparing a magnetic conductive wire according to any one of claims 1 to 6, characterized in that: The following steps are involved: Taking the guide wire with the first end of the core wire exposed; A first annular magnet and a second annular magnet are sleeved on the first end, and the interval area is covered with magnetic ink, which forms a magnetic fluid coating layer after solidification.

8. A catheter, characterized in that The magnetic conductive wire comprises the magnetic conductive wire according to any one of claims 1 to 6.

9. A medical device, characterized in that The magnetic guide wire comprises any one of claims 1 to 6, or the catheter comprises the catheter according to claim 8.

10. The method for controlling a magnetic conductive wire according to any one of claims 1 to 6, characterized in that: The following steps A1 and A2 are included: A1: transporting the magnetic guide wire from the first end to the destination pipeline; A2: The bending deformation of the first end is controlled by an external magnetic field to adjust the movement direction of the magnetic wire, and the second end is clamped by an external transmission device to control the forward or backward movement of the magnetic wire.

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