Interventional guide wire with three-dimensional force sensor at the tip and real-time detection of three-dimensional force

Abstract

The application discloses a guide wire tip three-dimensional force sensor and an interventional guide wire for three-dimensional force real-time detection, and belongs to the technical field of optical fiber sensing and medical instruments. The guide wire tip three-dimensional force sensor comprises a polymer material base, three optical fiber Bragg gratings and a resin tip, and the optical fiber Bragg gratings are embedded in the polymer material base; a guide wire magnetic control unit is integrated at the proximal end of the force sensing array, and is made of polymer material mixed with magnetic particles; and a nickel-titanium alloy spring tube is connected with the proximal end of the guide wire magnetic control unit. The medical guide wire realizes high-precision real-time detection of three-dimensional flexible contact force in a delivery process through a sensing array, and significantly improves the safety of a vascular interventional operation; meanwhile, the guide wire is endowed with magnetic navigation capability through the magnetic control unit, so that the control difficulty in a complex curved blood vessel is overcome, and the flexibility and direction control precision of the guide wire are effectively improved.

Description

Technical Field

[0001] This invention belongs to the field of fiber optic sensing and medical device technology, and particularly relates to a three-dimensional force sensor at the tip of a guidewire and an interventional guidewire for real-time detection of three-dimensional force. Background Technology

[0002] Cardiovascular disease is the leading cause of death in my country, affecting 330 million people. It accounts for nearly 50% of all deaths among urban and rural residents, ranking first in the country. In 2021, it accounted for 48.98% and 47.35% of deaths in rural and urban areas, respectively. Furthermore, the prevalence and number of surgeries related to cardiovascular disease are continuously increasing. Cardiovascular diseases are mostly caused by arterial blockage leading to abnormal blood supply, the root cause of which is atherosclerosis: long-term deposition of lipids, platelet products, and calcium salts in the blood forms plaques, causing narrowing of the blood vessel lumen and increased blood flow resistance. Lipid-rich, vulnerable plaques are easily ruptured by mechanical stress or inflammation, and the exposed procoagulant factors can induce thrombus formation. The continuous accumulation and organization of thrombi can cause blood vessels to progress from partial narrowing to chronic total occlusion (CTO), interrupting distal blood flow. If this occurs in a major blood vessel without collateral circulation compensation, the corresponding tissues will experience ischemic necrosis.

[0003] In traditional percutaneous vascular interventional procedures, the surgeon first punctures the patient's femoral artery with a needle. Then, using imaging data provided by angiography, the catheter and guidewire are guided to the lesion site to perform treatments such as tissue ablation, plaque rotational atherectomy, and stent implantation. Throughout this process, the guidewire serves as the core guiding instrument, playing a crucial role in establishing access, precise navigation, and supporting the catheter. Under real-time monitoring with DSA images, the surgeon manipulates the proximal end of the guidewire, controlling its direction and trajectory, guiding it through tortuous segments, stenotic areas, and even occluded lesions to safely reach the target vessel. The guidewire must maintain sufficient support while possessing good flexibility and maneuverability to avoid damaging the vascular intima, inducing spasm, or dissection. After successfully passing through the lesion, the guidewire acts as a track, providing a stable path for subsequent catheters, balloons, stents, and other devices, forming the foundation for ensuring the safe, precise, and efficient completion of the interventional procedure.

[0004] Guidewire manipulation demands considerable experience from the operator; improper operation can easily lead to serious complications such as vascular tearing, perforation, and thrombosis, as well as prolonging operation time and increasing the risk of radiation exposure and recurrence. Interventional guidewires that combine precise magnetic field steering navigation with real-time three-dimensional force detection at the tip not only improve surgical precision, efficiency, and safety but also compensate for the lack of tactile feedback, effectively reducing operational difficulty and demonstrating significant clinical application value.

[0005] Therefore, it is necessary to provide an interventional guidewire with a three-dimensional force sensor at the guidewire tip and real-time three-dimensional force detection to improve the safety of vascular interventional surgery; at the same time, it is essential to provide the guidewire with magnetic navigation capability through a magnetic control unit, which overcomes the difficulty of manipulation in complex and tortuous blood vessels and improves the flexibility and directional control accuracy of the guidewire. Summary of the Invention

[0006] In view of this, the present invention proposes an integrated three-dimensional force sensor at the tip of an interventional guidewire. The guidewire diameter can be customized by adjusting the size of the mold, which can be adapted to different surgical scenarios. Furthermore, the sensor substrate material is a flexible polymer material, which gives the sensor extremely high sensitivity. The interventional guidewire tip is integrated with a magnetic drive unit, which can give the guidewire the ability to flexibly turn under a spatial magnetic field, effectively reducing the difficulty of guidewire operation.

[0007] On one hand, the present invention provides a three-dimensional force sensor for a guidewire tip, comprising: Polymer material substrate; Three fiber Bragg gratings are embedded in a polymer substrate in a circumferentially evenly distributed arrangement. The resin tip is located at one end of the polymer material substrate; The polymer material substrate is formed by combining a PDMS matrix with a curing agent.

[0008] Based on the above technical solutions, the preferred method for preparing the polymer material substrate is to mix the PDMS matrix with the curing agent and stir thoroughly to obtain a mixture; then place the mixture in a defoamer for vacuum defoaming to remove the air bubbles introduced during the stirring process.

[0009] Preferably, the mass ratio of PDMS matrix to curing agent is 10:1.

[0010] Based on the above technical solutions, the preferred method for fabricating the three-dimensional force sensor at the guidewire tip includes the following steps: The PTFE tube mold and the fiber positioning plates set at both ends of the PTFE tube mold are fixed by 3D printed fasteners. The fiber positioning plates are provided with fiber positioning holes that limit the position of the fiber. The PTFE pipe mold is fixed in the fastener by adhesive bonding; The fiber Bragg grating is passed sequentially through the fiber positioning holes on the PTFE tube mold and the fiber positioning plates at both ends. The polymer material substrate, after vacuum degassing, is injected into the PTFE pipe mold and cured in a constant temperature oven at 60°C for 3 hours. The cured polymer material substrate is demolded, and a hemispherical resin tip is prepared at one end of the polymer material substrate using UV-cured resin.

[0011] On the other hand, the present invention provides an interventional guidewire for real-time three-dimensional force detection, comprising: Configure the aforementioned three-dimensional force sensor at the guidewire tip; The guidewire magnetic control unit is integrated into the proximal end of the three-dimensional force sensor at the tip of the guidewire; The front end of the nickel-titanium alloy spring tube extends into the integrated interior of the guide wire magnetic control unit, and the extended front end and the integrated guide wire magnetic control unit form a mechanical interlock. The guide wire magnetic control unit is integrated with the three-dimensional force sensor at the tip of the guide wire by fitting a mold on the proximal end of the three-dimensional force sensor at the tip of the guide wire and performing magnetic hybrid material injection molding.

[0012] Based on the above technical solutions, the preferred method for preparing an interventional guidewire with real-time three-dimensional force detection includes the following steps: Neodymium iron boron particles were pretreated and mixed with PDMS material to obtain a magnetic hybrid material; The pigtails of the three fiber Bragg gratings of the three-dimensional force sensor at the tip of the guidewire are passed through the PTFE tube mold and the nickel-titanium alloy spring tube, respectively. Inject the magnetic hybrid material into the PTFE tube mold, and place the nickel-titanium alloy spring tube coaxially into the PTFE tube mold; place the assembled whole into a constant temperature oven and cure at 60°C for 3 hours. After demolding, an interventional guidewire with real-time three-dimensional force detection is obtained.

[0013] Preferably, the neodymium iron boron particles are pretreated, including the following: The neodymium iron boron particles were evenly spread on a clean stainless steel tray and placed in a drying oven at 70–80°C for continuous drying to fully remove adsorbed moisture and solvent residue from the surface and pores. The dried neodymium iron boron particles were immersed in anhydrous ethanol solution and the surface adsorbed oil, oxide layer and mechanical impurities were removed by cleaning. An ethanol-silane coupling agent solution with a mass fraction of 1-3% was prepared using a silane coupling agent. The cleaned NdFeB particles were added to the ethanol-silane coupling agent solution and reacted with magnetic stirring at 60°C for 1 hour. This allowed the -Si-OH formed by silane hydrolysis to undergo a condensation reaction with the hydroxyl groups or oxide layer on the particle surface, forming a dense organic-inorganic protective film. The film was then filtered, washed, and dried. The dried neodymium iron boron particles are poured into an agate grinding mortar for grinding and dispersion, and the clumps formed during drying are crushed to obtain a fine powder.

[0014] Preferably, the silane coupling agent is KH550 or KH570.

[0015] Preferably, the guide wire magnetic control unit is magnetized using a magnetizer before use.

[0016] The present invention provides a three-dimensional force sensor at the tip of a guidewire and an interventional guidewire for real-time three-dimensional force detection, which has the following advantages compared with the prior art: 1. The three-dimensional force sensor at the guidewire tip provided by this invention embeds three fiber Bragg gratings (FBGs) in a circumferentially uniform manner within a polymer material substrate composed of a PDMS matrix and a curing agent, with a resin tip at one end of the substrate. The three FBGs, arranged circumferentially, can generate differentiated wavelength drift responses to the force components in the three orthogonal directions of X, Y, and Z. The PDMS material itself has good biocompatibility, flexibility, and low Young's modulus, and its mechanical properties are highly compatible with vascular tissue, significantly reducing the risk of damage to the vascular wall during guidewire intervention, making it suitable for long-term, dynamic human intervention applications. The FBG's embedded integrated structure design avoids the increased size caused by external packaging, which is conducive to achieving millimeter-level or even sub-millimeter-level sensor tips, meeting the space requirements for delicate operations in narrow blood vessels. The PDMS substrate forms a full-encapsulation protection for the FBG, effectively isolating the direct erosion of the fiber optic grating by external media such as blood and body fluids, while reducing the cross-sensitivity effects of temperature, refractive index, etc., and improving the long-term stability and reliability of the force sensing signal. The resin tip fabricated at the end of the PDMS substrate retains the smooth shape required by the guidewire to reduce the risk of puncture, and provides a stable strain transmission path for the FBG, balancing safety and sensing sensitivity.

[0017] 2. While retaining the high-precision three-dimensional force real-time detection function, a magnetically controllable driven unit is integrated, enabling the guidewire not only to sense the mechanical environment within the blood vessel but also to actively steer, navigate, and adjust its attitude using an external magnetic field. This significantly improves the throughput and maneuverability in complex vascular pathways. The magnetic control unit and sensor are integrated through injection molding, and a mechanical interlock structure is formed between the front end of the nickel-titanium alloy spring tube and the magnetic control unit. This effectively prevents interface separation or relative slippage caused by mechanical loads such as pushing, twisting, and bending during use, improving the fatigue resistance and clinical safety of the overall structure. The nickel-titanium alloy spring tube provides good pushing performance and shape memory capability, while the PDMS sensor segment maintains high flexibility. The two are integrated through a transitional connection, achieving a smooth mechanical match between the rigid drive segment and the flexible sensing segment, reducing stress concentration and lowering the risk of vascular injury.

[0018] 3. The PTFE tube mold and the fiber optic positioning plates at both ends are precisely fixed by 3D printed fasteners, and the FBG position is constrained by the fiber optic positioning holes. This ensures that the three FBGs are strictly evenly distributed in the circumference and centered in the axis, which significantly improves the symmetry of the sensor structure and the accuracy of three-dimensional force decoupling, and reduces the impact of assembly errors on sensing performance. The PTFE mold has excellent demolding performance and chemical inertness. Combined with the process conditions of constant temperature curing at 60℃ for 3 hours, the PDMS is slowly cross-linked at a stable temperature, reducing internal stress and deformation, and ensuring the dimensional accuracy and mechanical property consistency of the substrate. The hemispherical tip is formed by UV curing resin. The process is simple, the molding speed is fast, and the shape is controllable. The resulting tip surface is smooth and rounded, which not only reduces the risk of blood vessel puncture, but also provides a good strain transmission interface for the FBG and improves the sensitivity of axial force detection.

[0019] 4. After inserting the FBG pigtail into the PTFE mold and nickel-titanium alloy spring tube, a magnetic hybrid material is injected and coaxially placed into the spring tube, followed by overall curing. This achieves coaxial integration of the magnetic control unit, spring tube, and sensor segment, ensuring the consistency of the overall straightness and torsional transmission of the guidewire. The same 60℃, 3-hour curing process as the PDMS substrate is used to ensure that the magnetic control unit and sensor segment are consistent in thermodynamic conditions, reducing residual stress at the interface caused by differences in thermal expansion coefficients. After assembly, a magnetizer is used to uniformly magnetize the guidewire magnetic control unit to ensure consistent magnetic domain orientation and that the magnetic energy product meets the design requirements. This enables the guidewire to obtain stable and controllable deflection and guiding capabilities under an external magnetic field, meeting the clinical requirements for the precision of magnetically controlled guidewire manipulation. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the overall structure of the interventional guidewire with a three-dimensional force sensor at the tip of the guidewire and real-time three-dimensional force detection according to the present invention; Figure 2 This is a schematic diagram of the structure of a three-dimensional force sensor at the tip of a guidewire and a three-dimensional force sensor for real-time detection of interventional guidewires according to the present invention. Figure 3 This is a schematic diagram of the force applied to the three-dimensional force sensor at the tip of the guidewire and the three-dimensional force sensor for real-time detection of interventional guidewires according to the present invention. Figure 4 This is a schematic diagram of the mold structure of a guidewire tip three-dimensional force sensor and an interventional guidewire for real-time three-dimensional force detection according to the present invention; Figure 5 This is a schematic diagram of the integrated process of an interventional guidewire with a three-dimensional force sensor at the tip of the guidewire and real-time three-dimensional force detection, according to the present invention. Figure 6 This is a schematic diagram of the three-dimensional force calibration results of the interventional guidewire with a three-dimensional force sensor at the guidewire tip and real-time three-dimensional force detection according to the present invention.

[0022] Reference numerals: 1. Three-dimensional force sensor at the tip of the guide wire; 2. Magnetically controlled guide wire unit; 3. Nickel-titanium alloy spring tube; 1-1. Polymer substrate; 1-2. Resin tip; 1-3. First fiber Bragg grating; 1-4. Second fiber Bragg grating; 1-5. Third fiber Bragg grating; 4-1. Fixing component; 4-2. PTFE tube mold; 4-3. Fiber positioning plate; 4-4. Fiber positioning plate. Detailed Implementation

[0023] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0024] The guidewire needs to maintain sufficient support while possessing good flexibility and maneuverability to avoid damaging the vascular intima, inducing spasm, or dissection. After successfully passing through the lesion, the guidewire acts as a track, providing a stable path for subsequent catheters, balloons, stents, and other instruments. It is a fundamental step in ensuring the safe, precise, and efficient completion of interventional procedures. Guidewire manipulation requires considerable experience from the operator; improper operation can easily lead to serious complications such as vascular tearing, perforation, and thrombosis, and can also prolong the operation time, increase radiation exposure, and raise the risk of recurrence.

[0025] In view of this, such as Figure 1 and Figure 2 As shown, in one aspect, the present invention provides a three-dimensional force sensor 1 for a guidewire tip, comprising: Polymer material substrate 1-1; Three fiber Bragg gratings are embedded in the polymer substrate 1-1 in a circumferentially evenly distributed arrangement; the three fiber Bragg gratings correspond to... Figure 2 The markings 1-3, 1-4, and 1-5 in the text; The resin tip 1-2 is disposed at one end of the polymer material substrate 1-1; Polymer material substrate 1-1 is composed of a PDMS matrix and a curing agent, with a mass ratio of PDMS matrix to curing agent of 10:1. The preparation method of polymer material substrate 1-1 involves mixing the PDMS matrix and curing agent and stirring thoroughly to obtain a mixture; the mixture is then placed in a defoamer for vacuum defoaming to remove air bubbles introduced during stirring.

[0026] The three fiber Bragg gratings are embedded in a polymer substrate in a 1-1 integrated structure, avoiding the volume increase problem caused by external packaging. This facilitates the realization of millimeter-level or even sub-millimeter-level sensor tips, meeting the space requirements for fine operation in narrow blood vessels. The PDMS substrate provides full protection for the FBG, effectively isolating the fiber gratings from direct erosion by external media such as blood and body fluids. At the same time, it reduces the cross-sensitivity effects of temperature, refractive index, etc., improving the long-term stability and reliability of the force sensing signal. A resin tip is fabricated at the end of the PDMS substrate, which retains the smooth shape required for the guidewire to reduce the risk of puncture, and provides a stable strain transmission path for the FBG, balancing safety and sensing sensitivity.

[0027] To achieve three-dimensional force sensing, it is first necessary to establish the mapping relationship between the three-dimensional force acting on the sensor and the strain of the optical fiber. The theoretical model derivation process for the three-dimensional force sensor at the guide wire tip in this invention is as follows.

[0028] Soft materials undergo significant deformation under external forces, exhibiting typical nonlinear characteristics. Generally, hyperelastic constitutive models can reasonably describe the quasi-static deformation response of soft materials under external forces. In hyperelastic constitutive models, the strain energy density function of soft materials is typically written in the following form:

[0029] , formula 1; in For strain tensor invariants, the specific meaning is: , formula 2; in These represent the principal elongations in three different directions. To improve the accuracy of the theoretical model and consider its applicability under large strain conditions, a third-order Ogden model is chosen to describe the quasi-static deformation response of PDMS material under external force. The general form of the Ogden model has a strain energy density function expressed as the principal elongations in the three directions. The independent variable is represented as follows:

[0030] , formula 3; When the order N≥3 of the Ogden model, it can fit the experimental data with high accuracy, and when the PDMS Poisson's ratio μ=0.49, it can be approximated as an incompressible material. Therefore, the third-order Ogden hyperelastic constitutive model under incompressible conditions is finally selected, i.e., the ratio of deformed volume to undeformed volume. J =1. It is a material constant; subscript i , k It is a summation index. , This is a material constant used to describe the volumetric deformation of a material. The strain energy function is then expressed as follows:

[0031] , formula 4; refer to Figure 3 The relationship between the three-dimensional force and the strain of the fiber Bragg grating when the sensor is subjected to three-dimensional forces in all directions is analyzed as follows: 1) Z-direction: When the optical fiber and the PDMS substrate are subjected to the same axial force During operation, it is assumed that the PDMS matrix and optical fiber interface are tightly bonded with no interface slippage. For hyperelastic materials, the general expression for the principal stress is:

[0032] , Formula 5; in Indicates direction j The principal draw ratio, It is an arbitrary hydrostatic pressure introduced by incompressible constraints, used to ensure... For the incompressible Ogden model, substituting W and taking the partial derivative yields:

[0033] , Formula 6; The principal stresses are rewritten as: , Formula 7; Considering axial compression and tension, let , , formula 8; Based on the incompressible constraint, we obtain: , formula 9; Therefore Substituting these values ​​into the principal stress expression, we obtain the stresses in the three directions: , formula 10; , Formula 11; For free surfaces without lateral stress Thus, the hydrostatic pressure can be solved. : , Formula 12; Substituting into Equation 10, the axial principal stress is obtained as follows: , Formula 13; Since optical fiber is an elastic body, the principal stress of the optical fiber at this time can be expressed as: , Formula 14; in, The equivalent stiffness of the optical fiber including the coating layer. These are the Young's moduli of the glass core and the coating, respectively. These are the cross-sectional areas of the glass core and the coating layer, respectively.

[0034] Considering the axial force equilibrium of the cross section, the equilibrium equations are as follows: , Formula 15; in The cross-sectional area of ​​the PDMS matrix. This represents the cross-sectional area of ​​the optical fiber. This is the axial force.

[0035] After determining the parameters of the PDMS third-order Ogden model, the axial tensile ratio is obtained by substituting them into the above formula. λ The wavelength shift of the three optical fibers under axial force is: , Formula 16; in The initial center wavelength of the fiber Bragg grating. is the elastic-optic coefficient of the quartz optical fiber.

[0036] 2) X / Y direction: When the sensor is subjected to radial force F r When bent, the cylindrical sensor will bend, and its centerline will have curvature. k At this point, the axial strain of the embedded optical fiber will be determined by the tensile and compressive deformation caused by this curvature. Based on the bending equilibrium principle of a cantilever beam, the external bending moment of the sensor at the axial position z is:

[0037] , Formula 17; L The length of the sensor. Moment balance requires that the external bending moment equals the internal moment of the cross-section. Curvature k Functions:

[0038] , Formula 18; Due to the nonlinear characteristics of PDMS material, internal torque With curvaturek The relationship is nonlinear, therefore the distribution of curvature along the Z-axis is obtained by iteratively solving the above nonlinear equation at each discrete point.

[0039] Internal Moment of Composite Section Including torque contributed by the PDMS matrix The torque contributed by the three optical fibers : , Formula 19; The tensile ratio along the x-axis of the PDMS matrix under the pure bending assumption. With curvature k Distance from neutral layer x The following relationship must be satisfied: , Formula 20.

[0040] Nominal stress contributed by PDMS matrix Defined by the Ogden model: , Formula 21; Torque of PDMS By analyzing the net cross section of PDMS Integrating, we get: , formula 22; The torque contributed by the optical fiber is based on linear elasticity theory, but it needs to be corrected by introducing a local strain transfer coefficient: , Formula 23; in For optical fiber j Axial strain, , For optical fiber j Distance from the neutral layer.

[0041] Under the assumption of perfect bonding, the macroscopic strain of optical fiber After considering shear hysteresis, the actual strain of the optical fiber is: , Formula 24; in Let be the strain transfer function. Due to the stiffness mismatch between the PDMS matrix and the optical fiber and the low shear modulus of PDMS, strain transfer from the matrix to the optical fiber exhibits a hysteresis. We introduce a strain transfer coefficient using Shear-Lag theory. :

[0042] , formula 25; in β The Shear Lag feature parameter is defined as follows: , Formula 26; in G 0 represents the initial shear modulus of PDMS. R , r These are the radius of the PDMS and the radius of the optical fiber, respectively.

[0043] After obtaining the strain of each fiber along the z-axis, the average strain of the fiber can be obtained by definite integration: , Formula 27; For short beams with a length-to-diameter ratio less than 8, the Euler-Bernoulli principle neglects macroscopic shear deformation, leading to curvature... The curvature was overestimated. To correct this deficiency, a curvature correction factor based on the Timoshenko beam principle was introduced. : , Formula 28; in, This is a calibration constant obtained by matching theoretical results with finite element analysis at a specific length. It is used to characterize the effects of nonlinear materials and short beam effects. This constant needs to be recalibrated when the matrix material is changed or the cross-sectional geometry is altered. The final average strain is:

[0044] , Formula 29; Then the wavelength shift at this time is: , formula 30; When the sensor is subjected to a force in the X direction, the wavelength shift of each fiber Bragg grating is as follows: , formula 31; in r f This represents the distance between the fiber Bragg grating and the sensor axis.

[0045] When the sensor is subjected to a force in the Y direction, the wavelength shift of each fiber Bragg grating is as follows: , Formula 32.

[0046] In one embodiment, such as Figure 4 As shown, the fabrication method of the three-dimensional force sensor 1 at the guidewire tip includes the following steps: S1: The PTFE tube mold 4-2 and the fiber positioning plates 4-3 and 4-4 set at both ends of the PTFE tube mold 4-2 are fixed by the 3D printed fastener 4-1. The fiber positioning plates are provided with fiber positioning holes that limit the position of the fiber. S2: Fix the PTFE pipe mold 4-2 to the fastener 4-1 by adhesive bonding; S3: Pass the fiber Bragg grating sequentially through the fiber positioning holes on the PTFE tube mold 4-2 and the fiber positioning plates at both ends; S4: Inject the material of the polymer material substrate 1-1 after vacuum degassing treatment into the PTFE pipe mold 4-2, and cure it in a constant temperature oven at 60°C for 3 hours. S5: Demold the cured polymer material substrate 1-1 and prepare a hemispherical resin tip 1-2 at one end of the polymer material substrate 1-1 using UV-cured resin.

[0047] In addition, the present invention provides an interventional guidewire for real-time three-dimensional force detection, comprising: Configure the above-mentioned three-dimensional force sensor 1 at the tip of the guidewire; The guide wire magnetic control unit 2 is integrated into the proximal end of the three-dimensional force sensor 1 at the tip of the guide wire; The front end of the nickel-titanium alloy spring tube 3 extends into the integrated interior of the guide wire magnetic control unit 2, and the extended front end and the guide wire magnetic control unit 2 form a mechanical interlock. The guide wire magnetic control unit 2 is integrated with the three-dimensional force sensor at the tip of the guide wire by fitting a mold on the proximal end of the three-dimensional force sensor 1 at the tip of the guide wire and performing magnetic hybrid material injection molding.

[0048] In one embodiment, the portion of the nickel-titanium alloy spring tube 3 that extends into the guide wire magnetic control unit 2 is provided with anchoring holes or sparse spring pitch, which facilitates a mechanically interlocked mechanical connection with the guide wire magnetic control unit 2.

[0049] The method for preparing the interventional guidewire with real-time three-dimensional force detection includes the following steps: S1: Pre-treating neodymium iron boron particles and mixing them with PDMS material to obtain a magnetic hybrid material; S2: Pass the three fiber Bragg gratings of the three-dimensional force sensor 1 at the tip of the guide wire through the PTFE tube mold 4-2 and the nickel-titanium alloy spring tube 3 respectively. S3: Inject the magnetic hybrid material into the PTFE tube mold 4-2, and place the nickel-titanium alloy spring tube 3 coaxially into the PTFE tube mold 4-2; place the assembled whole into a constant temperature oven and cure at 60°C for 3 hours. S4; Demolding process is performed to obtain an interventional guidewire with real-time three-dimensional force detection.

[0050] The inner diameter of the PTFE tube mold 4-2 used here is adapted to the inner diameter of the three-dimensional force sensor at the tip of the guide wire.

[0051] The magnetic hybrid material is obtained by mixing PDMS material with NdFeB particles. To ensure the performance and process stability of the magnetic hybrid material, the NdFeB particles need to be pretreated. Pretreatment can significantly improve the dispersion of particles, preventing them from agglomerating in the polymer matrix, thereby ensuring uniform coating thickness and consistent magnetic properties. Simultaneously, surface activation or coupling agent modification can enhance the interfacial bonding between the particles and the polymer, improving overall mechanical strength and durability. Furthermore, NdFeB powder is susceptible to oxidation, leading to magnetic property decay. Pretreatment can form a protective layer on its surface, improving resistance to damp heat, corrosion, and aging, and stabilizing magnetic response characteristics. The pretreatment of NdFeB particles includes the following:

[0052] The neodymium iron boron particles were evenly spread on a clean stainless steel tray and placed in a drying oven at 70–80°C for continuous drying to fully remove adsorbed moisture and solvent residue from the surface and pores. The dried neodymium iron boron particles were immersed in anhydrous ethanol solution and the surface adsorbed oil, oxide layer and mechanical impurities were removed by cleaning. An ethanol-silane coupling agent solution with a mass fraction of 1-3% was prepared using a silane coupling agent. The cleaned NdFeB particles were added to the ethanol-silane coupling agent solution and reacted with magnetic stirring at 60°C for 1 hour. This allowed the -Si-OH formed by silane hydrolysis to undergo a condensation reaction with the hydroxyl groups or oxide layer on the particle surface, forming a dense organic-inorganic protective film. The film was then filtered, washed, and dried. The dried neodymium iron boron particles are poured into an agate grinding mortar for grinding and dispersion, and the clumps formed during drying are crushed to obtain a fine powder.

[0053] In one embodiment, the silane coupling agent is KH550 or KH570.

[0054] The magnetic field of the wire magnetic control unit 2 is relatively weak when it is not magnetized. In order to improve the magnetic control performance of the wire magnetic control unit 2, the wire magnetic control unit 2 is magnetized by a magnetizer before use.

[0055] To verify the effectiveness of the present invention, the parameter values ​​of the three-dimensional force sensor at the guidewire tip are given in the table below.

[0056]

[0057] Using the above parameters, a three-dimensional force calibration was performed on a miniature sensor measuring only 0.89 mm × 1 mm. Test results show that the sensor's sensitivities in the X, Y, and Z axes reach 2273.31 pm / N, 3222.90 pm / N, and 1200.56 pm / N, respectively, and the coefficients of determination (R²) of the fitted lines in each direction are all greater than 0.95, fully demonstrating that this miniature sensor possesses high sensitivity and good linear response characteristics in three-dimensional force sensing. Calibration results are referenced... Figure 6 As shown.

[0058] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A three-dimensional force sensor at the tip of a guidewire, characterized in that, include: Polymer material substrate; Three fiber Bragg gratings are embedded in a polymer substrate in a circumferentially evenly distributed arrangement. The resin tip is located at one end of the polymer material substrate; The polymer material substrate is formed by combining a PDMS matrix with a curing agent.

2. The three-dimensional force sensor at the tip of a guidewire according to claim 1, characterized in that, The preparation method of the polymer material substrate is to mix the PDMS matrix with the curing agent and stir it thoroughly to obtain a mixture; the mixture is then placed in a defoamer for vacuum defoaming to remove the air bubbles introduced during the stirring process.

3. A three-dimensional force sensor for a guidewire tip according to claim 2, characterized in that, The mass ratio of PDMS matrix to curing agent is 10:

1.

4. A three-dimensional force sensor for a guidewire tip according to claim 2, characterized in that, The fabrication method of the three-dimensional force sensor at the guidewire tip includes the following steps: The PTFE tube mold and the fiber positioning plates set at both ends of the PTFE tube mold are fixed by 3D printed fasteners. The fiber positioning plates are provided with fiber positioning holes that limit the position of the fiber. The PTFE pipe mold is fixed in the fastener by adhesive bonding; The fiber Bragg grating is passed sequentially through the fiber positioning holes on the PTFE tube mold and the fiber positioning plates at both ends. The polymer material substrate, after vacuum degassing, is injected into the PTFE pipe mold and cured in a constant temperature oven at 60°C for 3 hours. The cured polymer material substrate is demolded, and a hemispherical resin tip is prepared at one end of the polymer material substrate using UV-cured resin.

5. An interventional guidewire for real-time three-dimensional force detection, characterized in that, include: The three-dimensional force sensor at the tip of the guidewire as described in any one of claims 1-4; The guidewire magnetic control unit is integrated into the proximal end of the three-dimensional force sensor at the tip of the guidewire; The front end of the nickel-titanium alloy spring tube extends into the integrated interior of the guide wire magnetic control unit, and the extended front end and the integrated guide wire magnetic control unit form a mechanical interlock. The guide wire magnetic control unit is integrated with the three-dimensional force sensor at the tip of the guide wire by fitting a mold on the proximal end of the three-dimensional force sensor at the tip of the guide wire and performing magnetic hybrid material injection molding.

6. The interventional guidewire for real-time three-dimensional force detection according to claim 5, characterized in that, The method for preparing an interventional guidewire with real-time three-dimensional force detection includes the following steps: Neodymium iron boron particles were pretreated and mixed with PDMS material to obtain a magnetic hybrid material; The pigtails of the three fiber Bragg gratings of the three-dimensional force sensor at the tip of the guidewire are passed through the PTFE tube mold and the nickel-titanium alloy spring tube, respectively. Inject the magnetic hybrid material into the PTFE tube mold, and place the nickel-titanium alloy spring tube coaxially into the PTFE tube mold; place the assembled whole into a constant temperature oven and cure at 60°C for 3 hours. After demolding, an interventional guidewire with real-time three-dimensional force detection is obtained.

7. The interventional guidewire for real-time three-dimensional force detection according to claim 5, characterized in that, Pretreatment of NdFeB particles includes the following: The neodymium iron boron particles were evenly spread on a clean stainless steel tray and placed in a drying oven at 70–80°C for continuous drying to fully remove adsorbed moisture and solvent residue from the surface and pores. The dried neodymium iron boron particles were immersed in anhydrous ethanol solution and the surface adsorbed oil, oxide layer and mechanical impurities were removed by cleaning. An ethanol-silane coupling agent solution with a mass fraction of 1-3% was prepared using a silane coupling agent. The cleaned NdFeB particles were added to the ethanol-silane coupling agent solution and reacted with magnetic stirring at 60°C for 1 hour. This allowed the -Si-OH formed by silane hydrolysis to undergo a condensation reaction with the hydroxyl groups or oxide layer on the particle surface, forming a dense organic-inorganic protective film. The film was then filtered, washed, and dried. The dried neodymium iron boron particles are poured into an agate grinding mortar for grinding and dispersion, and the clumps formed during drying are crushed to obtain a fine powder.

8. The interventional guidewire for real-time three-dimensional force detection according to claim 7, characterized in that, The silane coupling agent is KH550 or KH570.

9. The interventional guidewire for real-time three-dimensional force detection according to claim 7, characterized in that, Before use, the wire magnetic control unit is magnetized using a magnetizer.

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