Dual-mode magnetic control guide wire based on permanent magnet-electromagnetism hybrid drive and application of dual-mode magnetic control guide wire

Abstract

The invention discloses a dual-mode magnetic control guide wire based on permanent magnet-electromagnetic hybrid drive. The dual-mode magnetic control guide wire comprises a guide wire (1-2), a permanent magnet (1-1) and a micro coil (1-3), wherein the permanent magnet (1-1) is installed at the head end of the guide wire (1-2), the magnetization direction of the permanent magnet (1-1) is arranged in the axial direction of the guide wire (1-2), the miniature coil (1-3) is installed on the side, opposite to the movement direction of the guide wire (1-2), of the permanent magnet (1-1), and the miniature coil (1-3) is wound by multiple circles of wires. The head end of the guide wire (1-2) is provided with a fixed magnetic moment source and a controllable magnetic moment source at the same time. The invention further discloses application of the dual-mode magnetic control guide wire based on permanent magnet-electromagnetic hybrid drive in interventional medical instruments.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, specifically to a dual-mode magnetically controlled guidewire based on permanent magnet-electromagnetic hybrid drive and its application. Background Technology

[0002] In interventional vascular surgery, the guidewire is a core instrument for establishing the surgical path and achieving minimally invasive treatment. Its maneuverability directly affects the precision of the procedure, the duration of the operation, and patient safety. Traditional interventional guidewires lack active steering capability at the tip. When encountering bends or bifurcations in the blood vessel, the physician needs to adjust the direction of the tip by rotating and pushing it from the rear. However, as the guidewire advances within the blood vessel, especially in deep vessels, the torque from the rear end is difficult to effectively transmit to the tip, easily leading to "torque accumulation." When this accumulated energy is suddenly released, the guidewire tip experiences a momentary, large jump. This not only reduces maneuverability but also significantly increases the risk of vascular injury and unpredictable surgical complications.

[0003] Endovascular interventional surgery plays a crucial role in the diagnosis and treatment of cardiovascular and cerebrovascular diseases, and its effectiveness depends on the navigation ability of the guidewire in complex vascular structures. During the procedure, the guidewire is manipulated by the surgeon pushing and rotating it at the rear end. However, due to the complexity of the procedure, this method often leads to prolonged operation time, increased radiation exposure, and even complications such as vascular dissection or perforation. To address these issues, magnetically driven guidewires have received widespread attention in recent years and are considered a highly promising solution. Most existing magnetically controlled guidewires employ a method of embedding a permanent magnet at the tip, which is then attracted and driven by an external magnetic field to achieve different directional steering. Because the magnetization direction of the permanent magnet is fixed, its bending shape and programmability are limited, making it difficult to achieve multi-segment flexible bending. Furthermore, this type of manipulation method relying on a single magnetic attraction force has significant limitations. First, under the influence of a magnetic field gradient, the permanent magnet will generate a sudden attractive acceleration, causing the guidewire tip to deflect abruptly or jump instantaneously, which can easily impact the vessel wall, increasing the risk of intimal damage, dissection, or even perforation. This problem is particularly pronounced when navigating complex bifurcations, sharp bends, or deep vessels, and has become a significant obstacle to the clinical translation of magnetically controlled guidewires. In vascular interventions using magnetically controlled guidewires, the ideal approach is to maintain push at the tip, while steering is entirely handled by an external magnetic field. Magnetic actuation is typically achieved by integrating a permanent magnet at the guidewire tip, relying on the attraction of the external magnetic field to drive its steering. For example, there is a type of magnetically driven, flexible, rotatable guidewire tip that can rotate to break up thrombus fragments through external magnetic field attraction; there are also multi-segment magnetically controlled guidewires that achieve higher-order curvature deformation through an external magnetic field. Furthermore, there is a variable-stiffness magnetically controlled guidewire that achieves multi-curvature control through three concentric, stretchable magnets.

[0004] However, due to the complexity of vascular structures, guidewires relying solely on permanent magnets often struggle to achieve truly multi-segment bending, limiting their programmable shape capabilities in branch vessels. To enhance the multi-segment deformability of guidewires, some studies have incorporated magnetic materials into flexible substrates, achieving multi-segment bending by adjusting the direction or degree of magnetization. For example, a tip structure made of magnetic material has been proposed, enabling multi-segment bending suitable for embolization and thrombectomy. Existing technology has also designed a magnetically controlled guidewire composed of magnetic particles, achieving large turning angles in three-dimensional space. Furthermore, a real-time in-situ magnetized reconfigurable guidewire has been proposed, achieving various programmable shapes through dynamically arranged magnetic units. Nevertheless, magnetically controlled guidewires based on magnetic materials or permanent magnets may still pose potential risks when relying entirely on magnetic attraction for manipulation. During turning operations, high acceleration may occur at the tip, potentially damaging the vessel. In deep vessels, due to decreased torque transmission efficiency at the rear end, accumulated torsional force may be released instantaneously at the tip, triggering a sudden release of elastic potential energy. Moreover, turning relying solely on attraction modes makes it difficult to achieve more precise and smoother bending control.

[0005] In contrast, adding a coil to the guidewire tip and generating magnetization by adjusting the current offers a safer and more controllable approach. Some studies have attempted to introduce miniature coils, controlling the direction of their magnetic moment through current to achieve controlled magnetization. However, limited by coil geometry, number of turns, and guidewire diameter, the magnetic moment generated by the coil is typically significantly weaker than that of a permanent magnet, requiring extremely high magnetic field strength or a large current to generate effective driving force. This makes it difficult to achieve usable levels in conventional clinical magnetic control systems. Furthermore, most interventional procedures cannot be performed under MRI conditions. Simultaneously, the inherently weaker magnetic moment of a coil compared to a permanent magnet means that in conventional interventional settings, a coil alone cannot provide sufficient driving force. Moreover, continuous coil energization leads to temperature rise, potentially posing a risk to surrounding tissues. Conversely, while embedding a permanent magnet at the guidewire tip provides a strong magnetic moment and avoids temperature rise issues, sudden deflection and potential energy release during suction mode are still difficult to prevent. Therefore, the core challenge lies in achieving safe, superselective navigation within complex blood vessels while maintaining a sufficiently large magnetic moment to ensure effective manipulation by the external magnetic field.

[0006] In summary, the disadvantages of existing technologies are: (1) Traditional guidewires lack active steering ability, and torque accumulation is prone to occur in deep blood vessels, leading to tip pulsation.

[0007] (2) Currently, most mainstream magnetically controlled guide wires have permanent magnets embedded at the tip and are redirected by applying an attractive force through an external magnetic field. However, the single attraction mode inevitably has the problem of high acceleration.

[0008] (3) Some coil-based magnetically controlled guidewires rely on the strong magnetic field provided by the MRI system for driving, but MRI equipment is bulky and expensive, and cannot be promoted to routine operating rooms and clinical interventional procedures. Summary of the Invention

[0009] The purpose of this invention is to provide a dual-mode magnetically controlled active steering guidewire based on permanent magnet-electromagnetic dual-mode attraction-repulsion drive and its application. This guidewire can provide powerful propulsion in complex vascular environments while achieving safe, compliant, and controllable multi-segment active bending, avoiding key defects of existing technologies such as high-acceleration deflection and sudden torque release. It provides a safer, more stable, and superselective navigation-capable novel magnetically controlled guidewire structure for vascular interventional surgery. This invention integrates an axially magnetized permanent magnet and an energized microcoil sequentially at the guidewire tip. Under the influence of an external magnetic field, the guidewire can achieve stable and continuous propulsion in attraction mode using the strong magnetic moment generated by the permanent magnet. In repulsion mode, the coil generates an adjustable magnetic moment with different current polarities and amplitudes, creating a superposition effect with the permanent magnet, thereby achieving active bending, straightening, and directional adjustment of the tip. This invention effectively avoids the sudden jumps and step deflections produced by traditional magnetically controlled guidewires under attraction drive, enabling precise and compliant active steering control without the need for rear-end rotation, and achieving superselective branch entry in complex vascular environments.

[0010] The first aspect of the present invention is to provide a dual-mode magnetically controlled guide wire based on permanent magnet-electromagnetic hybrid drive, comprising: a guide wire (1-2), a permanent magnet (1-1), and a micro coil (1-3); wherein, the permanent magnet (1-1) is mounted at the head end of the guide wire (1-2), the magnetization direction of the permanent magnet (1-1) is arranged along the axial direction of the guide wire (1-2), and the micro coil (1-3) is mounted on the side opposite to the direction of movement of the permanent magnet (1-1), the micro coil (1-3) being wound with multiple turns of wire, so that the head end of the guide wire (1-2) simultaneously has a fixed magnetic moment source and a controllable magnetic moment source.

[0011] Preferably, the guidewire (1-2) is a multi-layer composite structure formed by an outer layer, an intermediate layer and a core layer; wherein the outer layer is a medical-grade polyurethane or silicone-based polymer coating and the surface is hydrophilic; the intermediate layer is woven from multiple strands of superelastic nickel-titanium alloy wire; and the core layer is a nickel-titanium alloy core wire that has been heat-treated to obtain superelastic properties.

[0012] Preferably, the guidewire (1-2) is divided into a main shaft portion, a soft tip portion, and a tapered transition zone along the axial direction; the tapered transition zone is located at the end of the soft tip portion away from the main shaft portion, and the guidewire (1-2) adopts a linearly gradual hardness design, with the tapered transition zone ensuring a smooth transition.

[0013] Preferably, the permanent magnet (1-1) is made of sintered NdFeB N52 grade magnetic material.

[0014] Preferably, the permanent magnet (1-1) has a cylindrical structure and the magnetization direction is unipolar magnetization along the cylindrical axis.

[0015] Preferably, a diamond-like carbon (DLC) coating is deposited on the surface of the permanent magnet (1-1) using a physical vapor deposition (PVD) process to form a magnet encapsulation for the permanent magnet (1-1).

[0016] Preferably, the permanent magnet (1-1) and the guide wire (1-2) are fixedly connected by medical-grade epoxy resin adhesive.

[0017] Preferably, the miniature coil (1-3) is wound with multiple turns of wire, including: using enameled copper wire to tightly wind a solenoid to make multiple turns of wire.

[0018] Preferably, the permanent magnet (1-1) integrates a laser-assisted positioning system to ensure the magnetic orientation accuracy of the permanent magnet (1-1).

[0019] The second aspect of the present invention is to provide the application of the dual-mode magnetically controlled guidewire based on permanent magnet-electromagnetic hybrid drive in interventional medical devices.

[0020] The working method of the dual-mode magnetically controlled guide wire based on permanent magnet-electromagnetic hybrid drive proposed in this invention includes the following steps: (1) A directionally controllable magnetic field is established by an external permanent magnet or magnetic control device, so that the wire with the coil de-energized can be stably advanced along the magnetic field direction by the permanent magnet in the attraction mode, which is used for linear navigation of the main blood vessel path.

[0021] (2) When the guidewire reaches the bifurcation of the blood vessel or the position where the direction needs to be changed, a controllable magnetic moment is generated in the coil by passing a current of a specific polarity and amplitude through the coil. This forms a mixed magnetic source with the permanent magnet. The external magnetic field achieves active bending of the guidewire tip through the repulsion mode.

[0022] (3) Adjust the current magnitude and polarity according to feedback to make the bending angle continuously adjustable and accurately aligned with the target blood vessel branch, so as to achieve smooth turning and safe entry.

[0023] The beneficial effects of the method and system of the present invention are as follows: This invention integrates an axially magnetized permanent magnet with an energized microcoil at the guidewire tip, giving the guidewire both high magnetic moment response and adjustable magnetism. Magnetic repulsion drive enables guidewire tip bending, avoiding the risk of instantaneous hopping of the permanent magnet under attraction, thus improving the safety and predictability of vascular navigation. This invention utilizes a hybrid magnetic source composed of a permanent magnet and a microcoil to achieve coordinated driving in both attraction-propulsion and repulsion-bending modes. This allows the guidewire to achieve stable forward movement, continuously adjustable active three-dimensional steering, and compliant bending without the need for rear-end rotation. It significantly reduces the risk of hopping caused by torque accumulation and high-acceleration deviation under attraction mode, enhancing superselective navigation capabilities and operational safety in complex, multi-branched, and sharply curved vessels. It is a novel magnetically controlled guidewire that combines high magnetic moment driving force, compliant controllability, and clinical applicability. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the specific embodiments or related technologies of the present invention, the drawings used in the description of the specific embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of a dual-mode magnetized guide wire based on permanent magnet-electromagnetic hybrid drive according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the magnetically controlled guide wire in the attraction mode according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of the magnetically controlled guidewire in repulsion mode according to an embodiment of the present invention; Figure 4 This is a schematic diagram comparing the finite element simulation results and the analytical model calculation results provided according to an embodiment of the present invention; Figure 5 (a) A schematic diagram of the finite element simulation results of the magnetic force and magnetic torque acting on the permanent magnet and the micro coil according to an embodiment of the present invention; Figure 5 (b) Provided according to embodiments of the present invention Figure 5 (a) A schematic diagram showing the comparison between the finite element simulation results and the calculation results of the analytical model; Figure 6 A schematic diagram showing the guide wire tip turning angle when the distance between the miniature coil and the external permanent magnet is gradually increased from 50mm to 150mm in 10mm increments according to an embodiment of the present invention. Figure 7This is a schematic diagram showing the guide wire tip rotation angle when the current range is set to -1000mA to 1000mA and the step is 100mA, according to an embodiment of the present invention. Detailed Implementation

[0026] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0028] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0029] like Figure 1 As shown, a first aspect of the present invention is to provide a dual-mode magnetically controlled guide wire based on permanent magnet-electromagnetic hybrid drive, comprising: a guide wire (1-2), a permanent magnet (1-1), and a micro coil (1-3); when the magnetically controlled guide wire is in attraction mode, as... Figure 2 As shown, switching to the rejection mode is as follows: Figure 3 As shown; wherein, the permanent magnet (1-1) is installed at the head end of the guide wire (1-2), and the magnetization direction of the permanent magnet (1-1) is arranged along the axial direction of the guide wire (1-2). The micro coil (1-3) is installed behind the permanent magnet (1-1). The micro coil (1-3) is wound with copper wire in multiple turns, so that the head end of the guide wire (1-2) has both a fixed magnetic moment source and a controllable magnetic moment source, thereby enabling the guide wire (1-2) to have both strong driving force and flexible deformability while maintaining a small outer diameter.

[0030] In a preferred embodiment, the guidewire (1-2) is a multi-layer composite structure consisting of an outer layer, an intermediate layer, and a core layer to meet the dual requirements of small outer diameter, high torque transmission capability, and flexibility. The outer layer is a medical-grade polyurethane or silicone-based polymer coating with a thickness of 50-100 micrometers. Its surface is hydrophilically treated, resulting in a friction coefficient of less than 0.05, ensuring smooth movement within the blood vessel. The intermediate layer is woven from multiple strands of superelastic nickel-titanium alloy wire with a braiding angle of 45° and a braiding density of 16-24 picks / inch, providing excellent torque transmission efficiency (>85%) and torsional resistance. The core layer is a nickel-titanium alloy core wire with a diameter of 0.2-0.3 mm, which undergoes special heat treatment to obtain superelastic properties. The phase transition temperature Af is set at 25-30°C to ensure it maintains its superelastic state at body temperature.

[0031] In a preferred embodiment, the total length of the guidewire (1-2) includes three specifications: 180cm, 260cm, and 300cm, depending on clinical needs. The guidewire (1-2) is divided into a main shaft section, a soft tip section, and a tapered transition zone along the axial direction. The tapered transition zone is located at the end of the soft tip section away from the main shaft section. The diameter of the main shaft section of the guidewire (1-2) is 0.89mm, tapering to 0.64mm at the tip. The length of the soft tip section of the guidewire (1-2) is 3-5cm, and it adopts a linearly gradual hardness design, with the hardness gradually decreasing from Shore A 90 to A 40. The length of the tapered transition zone of the guidewire (1-2) is 8-12mm, with a taper ratio of 1:20 to ensure a smooth transition.

[0032] In a preferred embodiment, the method for preparing the guidewire (1-2) includes: (1) Core wire processing: Vacuum melting-hot extrusion-cold drawing process is adopted, and the final cold working deformation is controlled at 30-40%. Then, aging treatment is carried out at 500-550℃ for 2-4 hours. (2) Braiding layer forming: Braiding is carried out on a special braiding machine with constant tension (20-30g / strand), and after braiding, it is set at 450℃ for 30 minutes; (3) Coating process: The dip-coating-curing process is adopted. The coating is applied in two layers. After each coating, it is cured at 80°C for 30 minutes and finally sterilized by γ-ray.

[0033] In a preferred embodiment, the permanent magnet (1-1) is made of sintered neodymium iron boron (NdFeB) N52 grade magnetic material, which has high magnetic energy product (≥400kJ / m³) and high coercivity (≥1350kA / m); the permanent magnet (1-1) has a cylindrical structure with a diameter of 0.5±0.02mm, a length of 5.0mm, and a volume of approximately 0.91-1.06mm³; the magnetization direction of the permanent magnet (1-1) is unipolar magnetization along the cylindrical axis, and the surface magnetic field strength is 300-400mT at a distance of 0.5mm from the surface; the magnetic moment of the permanent magnet (1-1) is approximately 1.3T for saturation magnetization and approximately 3.7mA·m².

[0034] In a preferred embodiment, a 3-5 micrometer thick diamond-like carbon (DLC) coating is deposited on the surface of the magnet using a physical vapor deposition (PVD) process to form a magnet encapsulation for the permanent magnet (1-1), providing chemical isolation while maintaining a minimum size increase; the permanent magnet (1-1) and the guide wire (1-2) are fixedly connected using a medical-grade epoxy resin adhesive with a bonding area ≥85% and a shear strength ≥15MPa; the magnetic orientation accuracy of the permanent magnet (1-1) is ensured by a laser-assisted positioning system, thereby ensuring that the deviation between the magnetization direction of the permanent magnet (1-1) and the axis of the guide wire (1-2) is controlled within ±2°.

[0035] In a preferred embodiment, the method for preparing the permanent magnet (1-1) includes: (1) Perform magnet forming, including: using powder metallurgy process, isostatic pressing pressure of 200-250MPa, sintering temperature of 1080-1120℃, and holding for 2-3 hours; (2) Perform precision machining, including: centerless grinding with diamond grinding wheels, dimensional tolerance controlled within ±0.01mm, cylindricity ≤0.005mm; (3) Perform magnetization treatment, including: magnetization in a pulsed magnetic field with a magnetic field strength ≥ 5T and a pulse width of 10-15ms; (4) Perform biocompatibility treatment, including plasma cleaning before magnet assembly to remove surface contaminants and improve bonding reliability.

[0036] In a preferred embodiment, the miniature coil (1-3) has a coil structure consisting of a tightly wound solenoid made of enameled copper wire. The coil has an inner diameter of 0.7 mm, an outer diameter of 4.5 mm, and a length of 3.5-4.5 mm. The enameled copper wire is American Wire Gauge (AWG) 48 polyurethane enameled copper wire with a diameter of 0.10 mm (including a 0.035 mm insulation layer). The number of turns is 150-200, the number of winding layers is 4-6, and the DC resistance is 180-250 Ω (at 25°C). The inductance of the miniature coil (1-3) is approximately 1.5-2.5 mH, and the self-resonant frequency is >500 kHz. The current operating range of the miniature coil (1-3) includes a continuous operating current of 100-500 mA (generating a magnetic field of 0.294-1.471 mA·m). 2 The peak operating current is 1000mA (generating a magnetic field of 2.943mA·m). 2 The duration is <30 seconds, and the minimum control current is 2mA (generating a magnetic field of 0.005mA·m). 2 (For fine-tuning); at the center of the coil axis of the miniature coil (1-3) (1 mm from the coil end face), when the continuous operating current is 10 mA, an axial magnetic field of 0.025 mA·m is generated. 2 When the continuous operating current is 500mA, the axial magnetic field generated is 1.25mA·m. 2 When the peak operating current is 1000mA, the generated axial magnetic field is 2.943mA·m. 2 At the coil end face of the miniature coil (1-3), the magnetic field gradient is 2-5T / m; the response characteristics of the miniature coil (1-3) include: electrical time constant (L / R) of 0.8-1.5ms, mechanical response delay <5ms (from current change to the start of wire movement), and maximum magnetic field switching frequency >100Hz (suitable for dynamic adjustment).

[0037] As a preferred embodiment, the steady-state heat dissipation of the miniature coil (1-3) is: temperature rise < 8℃ under continuous operation at 500mA (ambient temperature 37℃); instantaneous heat capacity is: able to withstand 1000mA current for 18 seconds with a temperature rise < 7℃; heat dissipation design is: heat conduction and heat dissipation are carried out using the internal metal structure of the guide wire, thereby achieving an insulation resistance > 100MΩ (500VDC test), dielectric withstand voltage of 500VAC / 1 minute without breakdown, and leakage current < 10μA (under rated operating conditions).

[0038] In a preferred embodiment, the method for preparing the micro coils 1-3 includes: (1) Winding, including: using a precision CNC winding machine to wind the wire, with tension control of 0.5-1.0g and winding speed of 2000-3000rpm; (2) Manufacturing the skeleton, including: using polyimide (PI) material to laser process the skeleton with a wall thickness of 0.025 mm and thermal stability > 200℃; (3) Encapsulation includes: using UV-curable adhesive for interlayer fixation to complete the primary encapsulation; and using medical-grade epoxy resin for overall encapsulation to complete the secondary encapsulation, wherein the thickness of the medical-grade epoxy resin is 0.02-0.03 mm. (4) Implement termination process, including: laser micro-welding of 30AWG silver-plated copper wire to the micro wire (0.05mm in diameter) inside the guide wire; (5) Perform tests and calibrations, including: calibrating the magnetic field of each assembled coil in a standard Helmholtz coil and establishing a current-magnetic field correspondence table.

[0039] like Figure 2-3 As shown, the dual-mode working principle includes: 1. Attraction Mode ( Figure 2 As shown, the micro coil (1-3) is not energized, and only the permanent magnet (1-1) participates in the magnetic field interaction. Relying on its fixed magnetic moment, it forms a stable attractive force in the magnetic field gradient generated by the external permanent magnet or magnetic control device, driving the guide wire (1-2) to advance along the target direction. 2. Rejection mode ( Figure 3 As shown): When the direction of the coil current is the same as the direction of the permanent magnet's magnetic field, a magnetic field superposition effect is generated, which enhances the magnetic field strength at the far end, and the guide wire tip will straighten; when the direction of the coil current is opposite to the direction of the permanent magnet's magnetic field, a local magnetic field cancellation effect is generated, which enables fine adjustment, and the guide wire tip will extend.

[0040] In a preferred embodiment, the steering angle range of the dual-mode magnetically controlled guidewire includes: in a uniform external magnetic field (0.1T), without coil excitation, the permanent magnet itself can generate a deflection of ±30°; with coil excitation (1000mA), the total steering angle is 60°; the steering accuracy of the dual-mode magnetically controlled guidewire includes: when using 12-bit DAC control, the theoretical angular resolution is 0.088°, the actual control accuracy is ±0.5° (considering mechanical hysteresis and friction), and the repeatability is ±1.2°; the mechanical characteristics of the dual-mode magnetically controlled guidewire include: under 1000mA excitation, it generates a steering torque of 2.0 × 10⁻⁶. -4 The time from the center position to the maximum turning angle is <0.2 seconds. After the magnetic field is removed, the guide wire recovers to a straight state within 0.1 seconds due to its superelasticity. The system control parameters of the dual-mode magnetically controlled guide wire include: adopting a digital-analog hybrid control interface, capable of outputting current with 16-bit resolution; stable operation in an external navigation magnetic field of 0.05-0.5T, with magnetic field compatibility; and transmitting control signals through a micro-coaxial cable (0.1mm in diameter) with a bandwidth >10kHz.

[0041] Figure 4 This paper presents a comparison between the finite element simulation results and the analytical model calculation results of this invention. By applying a forward or reverse current to the micro-coil (1-3), magnetic forces and magnetic torques in opposite directions can be generated, respectively. The permanent magnet (1-1) is positioned within a range of 50-150 mm from the micro-coil (1-3), and its corresponding magnetic induction intensity distribution is shown in the figure. By changing the polarity of the coil current, the overall magnetic induction intensity distribution in the head region of the guide wire (1-2) can be effectively adjusted, thereby achieving active control of the remote magnetic environment. Furthermore, the finite element simulation results of the magnetic force and magnetic torque acting on the permanent magnet (1-1) and the micro-coil (1-3) were actually extracted and compared with the calculation results of the analytical model. The results are shown in the figure. Figure 5 (a) and Figure 5 As shown in (b), it can be observed that as the distance between the external magnetic field and the tip of the guidewire (1-2) increases, the magnetic force and magnetic torque acting on the permanent magnet (1-1) and the microcoil (1-3) both show a gradually decreasing trend. Furthermore, the finite element simulation results and the analytical model results are highly consistent in their trends and very close in numerical values. This indicates that the dual-mode magnetically controlled guidewire proposed in this invention can achieve stable switching and precise control between attraction and repulsion modes under the manipulation of an external magnetic field, thereby enabling stable advancement and fine steering control of the guidewire tip in complex vascular environments. This provides a highly safe, maneuverable, and precisely navigation-enabled magnetically controlled interventional solution for vascular interventional surgery. To evaluate the steering characteristics of the dual-mode magnetically controlled guidewire proposed in this invention, a steering experiment was conducted by applying a current of ±1000mA to the microcoil (1-3). During the experiment, the relative positional relationship between the external permanent magnet and the tip of the guide wire (1-2) remained unchanged, and the distance between the micro coil (1-3) and the external permanent magnet was gradually increased from 50mm to 150mm in 10mm increments; the corresponding turning angle of the tip of the guide wire (1-2) was as follows. Figure 6 As shown, it can be observed that the turning angle of the guide wire (1-2) tip gradually decreases with the increase of the control distance. When the magnetic induction intensity generated by the external permanent magnet is too weak to induce the micro coil (1-3) to produce an active turning action, the guide wire (1-2) tip returns to the pre-bent state. The above results show that, in repulsion mode, the dual-mode magnetically controlled guide wire proposed in this invention can achieve an adjustable turning angle under different control distance conditions, and the bending or straightening of the guide wire (1-2) tip can be achieved by changing the polarity of the current applied to the micro coil (1-3).

[0042] Furthermore, to evaluate the ability to adjust the direction of the guide wire (1-2) tip using current under a fixed control distance, the distance between the miniature coil (1-3) and the external permanent magnet was fixed at 50 mm. Direction control was achieved by changing the magnitude and polarity of the current applied to the miniature coil (1-3). Specifically, the current range was set to -1000 mA to 1000 mA in 100 mA increments; the corresponding turning angle at the guide wire (1-2) tip was as follows: Figure 7 As shown, the turning angle of the guidewire (1-2) tip increases with the increase of current amplitude, where the shaded area represents the controllable turning range of the guidewire (1-2) tip. Within this controllable range, the microcoil (1-3) causes the guidewire (1-2) tip to gradually transition from an extended state to a pre-bent state under the action of a negative current, and further bends under the action of a positive current. The above results indicate that by controlling the magnitude and polarity of the current applied to the microcoil (1-3), the magnetically controlled guidewire proposed in this invention can achieve bending or straightening of the guidewire (1-2) tip in a repulsive mode, possessing good controllable turning performance. It can be used for superselective navigation of vascular branches under magnetic repulsion, thereby improving the flexibility and accessibility of endovascular interventional procedures.

[0043] The detailed parameters above are based on the engineering prototype and in vitro test data of the magnetically controlled guidewire. Fine-tuning is required before actual clinical application, taking into account specific vascular anatomy and clinical needs. This permanent magnet-electromagnetic hybrid drive design, through parameter optimization, achieves an effective turning angle of >60° for diameters <1mm, while maintaining good guidewire delivery and compliance, providing a new technical option for minimally invasive interventional surgery.

[0044] Working Principle: An adjustable external magnetic field is generated by an external permanent magnet or magnetically controlled device (e.g., a magnetically controlled robot). In attraction mode, the micro-coil (1-3) is not energized, and only the permanent magnet (1-1) participates in the magnetic field interaction. Relying on its fixed magnetic moment, it forms a stable attractive force in the magnetic field gradient generated by the external permanent magnet or magnetically controlled device, driving the guide wire (1-2) to advance along the target direction. In repulsion mode, by applying currents of different polarities and amplitudes to the micro-coil (1-3), the direction of the torque at the tip of the guide wire (1-2) in the external magnetic field is changed. When the magnetic moment of the micro-coil (1-3) is opposite to the direction of the permanent magnet (1-1) and the external magnetic field, the tip is driven by the repulsive torque and straightens; when the magnetic moment of the micro-coil (1-3) is in the same direction as the permanent magnet (1-1) and the external magnetic field, the repulsive torque is enhanced, increasing the bending amplitude. The steering angle can be continuously adjusted by regulating the current in the microcoil (1-3), and the bending direction can be switched by adjusting the polarity of the microcoil (1-3), enabling the guidewire to achieve active steering capability in three-dimensional space. Throughout the process, no twisting is required at the rear end of the guidewire; steering and propulsion are achieved entirely through the synergy of a hybrid magnetic source and an external magnetic field, avoiding the hopping risks associated with traditional mechanical torsion transmission methods. This results in highly safe and highly precise superselective vascular navigation.

[0045] Clinical application parameters include: 1. Vascular compatibility (1) Flexibility: The bending stiffness of the guidewire tip is 0.5-1.0 mN·mm², which can bend through blood vessels with a radius of <5 mm; (2) Push capability: Push efficiency > 75%, with no obvious lag; (3) Visibility: The position of the permanent magnet can be tracked by X-ray imaging (with a small amount of tantalum powder added) or MRI.

[0046] 2. Safety parameters (1) Biocompatibility: All materials comply with ISO 10993 biocompatibility standard; (2) Failure protection: The current control module has multiple overcurrent protections (hardware current limiting + software monitoring). (3) Magnetic field safety: The maximum local magnetic field generated is <0.1T, which is far lower than the field strength of clinical MRI (1.5-3T).

[0047] 3. Lifespan and Reliability (1) Mechanical life: >5000 complete bending cycles (radius 5mm, angle ±90°); (2) Electrical life: The coil can withstand >10 8 Subcurrent cycle (10-50mA square wave); (3) Storage stability: The annual magnetic decay rate of permanent magnets is <0.5%, and it retains >95% of its magnetic properties for 10 years.

[0048] The second aspect of the present invention is to provide the application of the dual-mode magnetically controlled guidewire based on permanent magnet-electromagnetic hybrid drive in interventional medical devices.

[0049] In this embodiment, by changing the shape and size of the magnet and the coil, and exchanging the positions of the magnet and the coil, it can be applied to various interventional medical devices.

[0050] The working method of the dual-mode magnetically controlled guide wire based on permanent magnet-electromagnetic hybrid drive proposed in this invention includes the following steps: (1) A directionally controllable magnetic field is established by an external permanent magnet or magnetic control device, so that the wire with the coil de-energized can be stably advanced along the magnetic field direction by the permanent magnet in the attraction mode, which is used for linear navigation of the main blood vessel path.

[0051] (2) When the guidewire reaches the bifurcation of the blood vessel or the position where the direction needs to be changed, a controllable magnetic moment is generated in the coil by passing a current of a specific polarity and amplitude through the coil. This forms a mixed magnetic source with the permanent magnet. The external magnetic field achieves active bending of the guidewire tip through the repulsion mode.

[0052] (3) Adjust the current magnitude and polarity according to feedback to make the bending angle continuously adjustable and accurately aligned with the target blood vessel branch, so as to achieve smooth turning and safe entry.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A dual-mode magnetically controlled guide wire based on permanent magnet-electromagnetic hybrid drive, characterized in that, include: The guide wire (1-2), permanent magnet (1-1), and micro coil (1-3) are provided. The permanent magnet (1-1) is installed at the head end of the guide wire (1-2). The magnetization direction of the permanent magnet (1-1) is arranged along the axial direction of the guide wire (1-2). The micro coil (1-3) is installed on the side opposite to the direction of movement of the guide wire (1-2) along the permanent magnet (1-1). The micro coil (1-3) is wound with multiple turns of wire so that the head end of the guide wire (1-2) has both a fixed magnetic moment source and a controllable magnetic moment source.

2. The dual-mode magnetically controlled guide wire based on permanent magnet-electromagnetic hybrid drive according to claim 1, characterized in that, The guidewire (1-2) is a multi-layer composite structure formed by an outer layer, an intermediate layer and a core layer; wherein the outer layer is a medical-grade polyurethane or silicone-based polymer coating and the surface is hydrophilic treated. The intermediate layer is woven from multiple strands of superelastic nickel-titanium alloy wire; the core layer is a nickel-titanium alloy core wire, which is heat-treated to obtain superelastic properties.

3. The dual-mode magnetically controlled guide wire based on permanent magnet-electromagnetic hybrid drive according to claim 2, characterized in that, The guidewire (1-2) is divided into a main shaft portion, a soft tip portion, and a tapered transition zone along the axial direction; the tapered transition zone is located at the end of the soft tip portion away from the main shaft portion, and the soft tip portion of the guidewire (1-2) adopts a linear gradient hardness design; the tapered transition zone of the guidewire (1-2) ensures a smooth transition.

4. The dual-mode magnetically controlled guide wire based on permanent magnet-electromagnetic hybrid drive according to claim 3, characterized in that, The permanent magnet (1-1) is made of sintered NdFeB N52 grade magnetic material.

5. A dual-mode magnetically controlled guide wire based on permanent magnet-electromagnetic hybrid drive according to claim 4, characterized in that, The permanent magnet (1-1) has a cylindrical structure and is magnetized in a unipolar direction along the cylindrical axis.

6. A dual-mode magnetically controlled guide wire based on permanent magnet-electromagnetic hybrid drive according to claim 5, characterized in that, A diamond-like carbon (DLC) coating is deposited on the surface of the permanent magnet (1-1) using a physical vapor deposition (PVD) process to form a magnet encapsulation for the permanent magnet (1-1).

7. A dual-mode magnetically controlled guide wire based on permanent magnet-electromagnetic hybrid drive according to claim 6, characterized in that, The permanent magnet (1-1) and the guide wire (1-2) are fixedly connected by medical-grade epoxy resin adhesive.

8. A dual-mode magnetically controlled guide wire based on permanent magnet-electromagnetic hybrid drive according to claim 7, characterized in that, The miniature coil (1-3) is wound with multiple turns of wire, including: using enameled copper wire to tightly wind a solenoid to make multiple turns of wire.

9. A dual-mode magnetically controlled guide wire based on permanent magnet-electromagnetic hybrid drive according to claim 8, characterized in that, The permanent magnet (1-1) integrates a laser-assisted positioning system to ensure the magnetic orientation accuracy of the permanent magnet (1-1).

10. The application of the dual-mode magnetically controlled guidewire based on permanent magnet-electromagnetic hybrid drive as described in any one of claims 1-9 in interventional medical devices.

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