An optical fiber guide wire and a method for controllable bending of its distal end

Abstract

This invention discloses an optical fiber guidewire and its distal controllable bending method, belonging to the field of medical device technology. The optical fiber guidewire includes: a guidewire body with a central cavity; a sensing optical fiber disposed within the cavity to acquire distal contact force and strain distribution; a bending control assembly disposed at the distal end, comprising at least two controllable bending nodes; each node includes a phase change chamber and partitioned electrodes, encapsulated with an electrically responsive phase change fluid; and a controller connected to the sensing optical fiber and electrodes. The controller outputs a voltage to specific electrodes, stimulating a fluid phase change to generate asymmetric stiffness, driving the guidewire to bend in a specific direction; and dynamically adjusts the voltage based on a comparison of the contact force and a safety threshold. This invention achieves large-angle bending through multi-node collaboration and instantaneous softening and force relief based on sensor feedback, significantly improving the efficiency and safety of passage through tortuous intracranial blood vessels.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and in particular to an optical fiber guidewire and a method for controllable bending of its distal end. Background Technology

[0002] Guidewires are crucial medical devices in interventional vascular surgery, establishing instrument delivery tracks and guiding subsequent instruments to the lesion site. In recent years, fiber optic guidewires have shown great potential in clinical applications due to their small size and integration of sensing functions such as contact force feedback. However, the intracranial vascular network is extremely complex and tortuous, with numerous large-angle branches. Existing fiber optic guidewires have poor bending performance and maneuverability in blood vessels, leading to difficulties in surgical path planning during actual interventional procedures, or making it difficult to strictly adhere to the predetermined surgical path, thus resulting in low efficiency in reaching the lesion.

[0003] To improve the pathfinding and maneuverability of guidewires, some guidewires with directional bending designs have emerged in the prior art. For example, Chinese invention patent CN 120837246 B discloses an aortic valve guidewire and its usage method. This patent discloses the technical feature of a deformation capsule, which, by embedding a deformation capsule in the head segment and sealing it with an electric field-sensitive viscoelastic fluid, generates a regional viscosity difference under the action of a non-uniform electric field, thereby driving the guidewire head to bend directionally. However, although this prior art achieves directional bending of the guidewire head, it can only achieve a bending angle of 15° to 30°, and still cannot smoothly pass through vascular branches with excessively large angles.

[0004] Due to the aforementioned limitations in the bending angle of existing guidewire tips, some more efficient and shorter routes that are more difficult to traverse due to their larger angles must be eliminated during preoperative surgical path planning. This prevents the adoption of more efficient solutions in preoperative surgical path planning, unnecessarily increasing surgical operation time and potential intraoperative risks.

[0005] Therefore, it is necessary to provide an optical fiber guide wire and a method for controllable bending of its distal end to solve the above problems. Summary of the Invention

[0006] This invention overcomes the shortcomings of the prior art and provides a method for controllable bending of an optical fiber guide wire and its distal end.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is: an optical fiber guide wire, comprising:

[0008] The guidewire body has an axially extending central cavity inside.

[0009] A sensing optical fiber, disposed inside the central cavity, is used to acquire the contact force and strain distribution at the distal end of the guidewire body; and

[0010] A bending control assembly is disposed at the distal end of the guidewire body and includes at least two controllable bending nodes spaced apart along the axial direction; each controllable bending node includes a phase change chamber surrounding the central cavity and multiple partitioned electrodes attached to the phase change chamber; the phase change chamber is encapsulated with an electroresponsive phase change fluid;

[0011] It also includes an externally configured controller that communicates and is electrically connected to the sensing optical fiber and each of the partition electrodes; the controller is configured to: output voltage to a specific partition electrode to excite the electro-responsive phase change fluid in the corresponding area to undergo a phase change to generate asymmetric stiffness, drive the guide wire body to bend in an directional manner; and dynamically adjust the output voltage of the partition electrode according to the comparison result of the contact force and the preset safety threshold.

[0012] In a preferred embodiment of the present invention, each phase change chamber is in the form of a hollow annular closed capsule, with its inner wall tightly fitted to the outer wall of the central cavity, and its outer wall wrapped in the polymer sheath of the guidewire body; the capsule wall of the phase change chamber is made of thermoplastic polyurethane elastomer.

[0013] The partitioned electrodes are arranged in a serpentine pattern on the outer surface of the phase change cavity, and each group of the serpentine lines adopts a dual-strand differential signal line design containing one positive electrode and one negative electrode.

[0014] The partitioned electrodes are physically isolated into at least two independent electrode regions along the axial direction of the phase change chamber, and their surfaces are covered with a biocompatible insulating layer and have pre-reserved conductive contacts.

[0015] In a preferred embodiment of the present invention, the electroresponsive phase change fluid comprises a dispersed phase and a continuous phase; the dispersed phase is a core-shell structured particle with barium titanate particles as the core layer and polyaniline conductive polymer coated on the surface as the shell layer; the continuous phase is an ultralight fluorosilicone oil.

[0016] The mass ratio of the dispersed phase to the continuous phase is 2.2 to 3.5:1;

[0017] The dispersed phase is also doped with multi-walled carbon nanotubes at a mass fraction of 0.5% to 2.0% of the total weight of the dispersed phase as a mechanically reinforcing phase.

[0018] In a preferred embodiment of the present invention, the guidewire body is divided into two sections along the axial direction, the distal end being made of medical polymer material and the proximal end being made of medical metal material;

[0019] The outer surface of the guidewire body is continuously covered with a polymer sheath.

[0020] In a preferred embodiment of the present invention, the polymer sheath of the guidewire body is etched with a microgroove array on the surface corresponding to the phase change chamber;

[0021] In the inner region of the preset bend, the axial spacing between adjacent microgrooves is 50–100 μm; in the outer region of the preset bend, the axial spacing between adjacent microgrooves is 100–150 μm.

[0022] In a preferred embodiment of the present invention, the sensing optical fiber adopts Bragg fiber grating sensing technology, including a core fiber extending along the axial direction of the central cavity and sensing nodes distributed thereon.

[0023] A strain sensing unit is provided at the exact axial position corresponding to each of the controllable bending nodes, and a force sensing unit is provided at the position adjacent to the head of the guide wire body.

[0024] In a preferred embodiment of the present invention, the bending control assembly includes a first bending node, a second bending node, and a third bending node distributed in series along the axial direction of the guide wire body;

[0025] The first axial distance between the first bending node and the second bending node is 10-15 mm, and the second axial distance between the second bending node and the third bending node is 15-20 mm.

[0026] The third bending node is configured to bend in the opposite direction to the first and second bending nodes under the drive of the controller, so that the outer wall of the third bending node abuts against the inner wall of the main blood vessel to form a reverse anchoring support point.

[0027] In a preferred embodiment of the present invention, a conductive film is attached to the surface of the guidewire body; each of the conductive films is connected to a group of partition electrodes through a designated conductive contact to form an independent conductive path and extend to the proximal end of the guidewire body to connect with the controller.

[0028] A method for controllable bending of the distal end of an optical fiber guidewire includes the following steps:

[0029] S1. Perform surgical path planning to determine the target route and expected bending parameters of the guidewire body in the vascular network;

[0030] S2. When the guidewire reaches the vascular branch at the farthest end of the guidewire body, a differential voltage is output to the specific zone electrode of the specific bending node according to the surgical path plan, driving the guidewire body to bend in a specific direction.

[0031] S3. Based on the mechanical feedback transmitted through the sensing fiber, the controller dynamically adjusts the output voltage to specific controllable bending nodes to automatically adjust the bending angle or achieve physical stress relief.

[0032] In a preferred embodiment of the present invention, in step S3, if the contact force distribution indicates that the actual pathfinding trajectory deviates from the expected trajectory or encounters a slight local obstruction, the controller adjusts the voltage input to the specific partition electrode to change the regional viscosity difference of the phase change fluid, thereby automatically adjusting the bending angle of the guidewire body.

[0033] If the obtained contact force value increases sharply and approaches the preset safety limit threshold, the controller instantly cuts off or significantly reduces the output voltage, causing the phase change fluid to instantly return to its low viscosity background state and eliminate internal asymmetric stiffness, resulting in the distal end of the guide wire body instantly softening to achieve physical force relief.

[0034] This invention addresses the shortcomings of the prior art and has the following beneficial effects:

[0035] (1) This invention provides an optical fiber guidewire and its controllable bending method at the distal end. At least two bending nodes containing phase change chambers and partitioned electrodes are connected in series at the distal end of the guidewire. An electrically responsive phase change fluid is enclosed inside, and a sensing optical fiber is built into the central cavity and connected to a controller. The controller output voltage excites the fluid phase change to generate asymmetric stiffness, driving directional bending; at the same time, the voltage is dynamically adjusted based on the contact force fed back by the optical fiber. This achieves multi-node collaborative superimposed large-angle bending, and instantly reduces the voltage to achieve physical softening and stress relief when the force is too large. Compared with the defects of existing single-node guidewires, which have limited bending angles and are prone to puncture risks due to blind path finding, this invention breaks through the physical bottleneck of angle, greatly improves the efficiency of passing through tortuous blood vessels, and constructs a safe closed loop of intelligent path finding and active anti-perforation.

[0036] (2) The electroresponsive phase change fluid of the present invention uses barium titanate-coated polyaniline core-shell particles as the dispersed phase, ultralight fluorosilicone oil as the continuous phase, and multi-walled carbon nanotubes as the reinforcing phase. When energized, the carbon nanotubes and polarized particles synergistically construct a three-dimensional cross-linked network to enhance the yield stress, while the light oil can offset the viscosity increase caused by the high solid content. This formulation enables the guide wire to maintain low viscosity and flexibility under zero electric field, and rapidly generates a strong eccentric torque to overcome the tube wall stiffness when energized. Compared with the defects of existing pure particulate fluids with weak driving force or conventional high-viscosity silicone oils causing response lag, this feature improves the driving response speed, eliminates the bending lag phenomenon, achieves transient precise guidance, and provides an extremely agile kinetic basis for emergency power-off and force relief.

[0037] (3) In this invention, a microgroove array is etched on the surface of the corresponding chamber of the guidewire sheath. The spacing between the microgrooves on the inner side of the bend is 50-100 μm, and on the outer side it is 100-150 μm, with a depth of 40%-70% of the wall thickness. This gradual arrangement and depth control create an asymmetric flexibility gradient in the circumferential direction. The microgrooves, as stress relief units, fully absorb the local tensile and compressive strain during bending. This significantly weakens the resistance on the pre-set bending side, allowing the internal torque to be efficiently converted into large-angle bending. Compared with the problem of the traditional guidewire having uniform circumferential stiffness, which leads to limited angle and easy sheath tearing, this structure effectively releases stress without damaging the electric field network, prolongs fatigue life, and provides ample structural clearance space for instantaneous physical stress relief.

[0038] (4) The bending control assembly of the present invention includes a first, second, and third bending node connected in series. The third node is controlled to bend in the opposite direction to the first two nodes to abut against the inner wall of the main blood vessel. When crossing a bifurcation, the first two nodes extend into the side branch, and the third node deflects in the opposite direction and controls the abutment force based on the dynamic fine-tuning voltage of the fiber optic feedback, forming a stable reverse anchoring support point. Its radial support force effectively counteracts the outward turning torque generated at the bifurcation when pushing the proximal end. Compared with the existing guidewires that are prone to slipping into the main blood vessel when crossing large-angle side branches, this feature fundamentally prevents guidewire slippage, ensuring that it is pushed deep into the side branch under stable force. While maintaining anchorage and avoiding intimal damage, it achieves a high degree of unity between pathfinding efficiency and safety. Attached Figure Description

[0039] 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 recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 This is a cross-sectional view of the optical fiber guide wire according to a preferred embodiment of the present invention;

[0041] Figure 2 yes Figure 1 A magnified view of part A;

[0042] Figure 3 This is a preferred embodiment of the controlled bending method for the distal end of the optical fiber guide wire according to the present invention;

[0043] In the figure: 1. Guidewire body; 11. Proximal end; 12. Distal end; 13. Polymer sheath; 2. Central cavity; 3. Sensing fiber; 4. Bending control assembly; 41. Phase change chamber; 42. Zoned electrode. Detailed Implementation

[0044] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. 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.

[0045] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein. Therefore, the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0046] Figure 1 A structural diagram of an optical fiber guidewire according to an embodiment of the present invention is shown. The optical fiber guidewire includes:

[0047] The guidewire body 1 has an axially extending central cavity 2 inside;

[0048] The sensing fiber 3, disposed inside the central cavity 2, is used to acquire the contact force and strain distribution at the distal end 12 of the guidewire body 1; and

[0049] The bending control assembly 4 is disposed at the distal end 12 of the guide wire body 1 and includes at least two controllable bending nodes distributed at intervals along the axial direction; each controllable bending node includes a phase change chamber 41 disposed around the central cavity 2 and multiple partitioned electrodes 42 attached to the phase change chamber 41; the phase change chamber 41 is encapsulated with an electrically responsive phase change fluid.

[0050] It also includes an externally configured controller that communicates and is electrically connected to the sensing fiber 3 and each partition electrode 42. The controller is configured to output voltage to a specific partition electrode 42, thereby exciting the electro-responsive phase change fluid in the corresponding area to undergo a phase change to generate asymmetric stiffness and drive the guide wire body 1 to bend in an directional manner. The controller is also configured to dynamically adjust the output voltage of the partition electrode 42 based on the comparison between the contact force and the preset safety threshold.

[0051] The fiber optic guidewire of this invention has at least two controllable bending nodes connected in series at the distal end 12 of the guidewire body 1. An external controller outputs a non-uniform voltage to the partitioned electrode 42 attached to the phase change chamber 41, which excites the internal phase change fluid to generate regional viscosity differences, causing the guidewire body 1 to bend directionally at each controllable bending node. This achieves multi-node collaborative superimposed bending, thus breaking through the physical bottleneck of the traditional single-node bending angle limitation. This allows the guidewire to pass smoothly through vascular branches with large angles, making more efficient surgical path planning possible. At the same time, the sensing fiber 3 in the central cavity 2 is used to obtain the contact force at the distal end 12 in real time, and the output voltage is dynamically adjusted based on the comparison result of the contact force and the preset safety threshold. This achieves automatic adjustment of the bending angle or instantaneous physical softening and force relief, constructing a safety closed loop that integrates intelligent dynamic path finding and active anti-perforation protection. This not only significantly improves the efficiency and precision of guidewire passage in extremely tortuous vascular networks, but also fundamentally eliminates the risk of endothelial damage caused by forced large-angle bending or blind force, providing an extremely reliable safety guarantee for highly complex intracranial vascular interventional surgery.

[0052] The following will describe in detail the specific implementation methods and working processes with reference to the accompanying drawings and multiple embodiments.

[0053] Example 1:

[0054] like Figure 1 As shown, an optical fiber guidewire includes: a guidewire body 1, a sensing optical fiber 3, a bending control assembly 4, and an externally mounted controller. The guidewire body 1 is a through-hole hollow tubular structure, divided into two sections along the axial direction: the distal end 12 is defined as the head-end execution section, and the proximal end 11 is defined as the operation connection section, i.e., the pushing section.

[0055] Specifically, the guidewire body 1 has an axially extending central cavity 2 inside. This central cavity 2 is an independent tube with closed ends, filled with dry inert gas. This central cavity 2 provides a physical channel for the suspension and penetration of the sensing optical fiber 3, placing the sensing optical fiber 3 in the mechanical center layer, protecting it from local compression when the guidewire bends and interference from the external blood environment.

[0056] Furthermore, the distal end 12 of the guidewire body 1 is made of a medical polymer material, including but not limited to polyimide, polyether block amide, or polyurethane. This polymer material imparts the required radial flexibility and structural compliance to the distal end 12. The bending control assembly 4 is built into and integrated into this distal end 12. The use of a polymer material for the distal end 12 of the guidewire body minimizes the bending stiffness of the structure itself, allowing the asymmetric bending moment generated when the electroresponsive phase change fluid within the controllable bending node forms a regional viscosity difference under a non-uniform electric field to be efficiently released, thereby achieving smooth large-angle bending of the combination of the two controllable bending nodes.

[0057] Corresponding to the high flexibility of the distal end 12, the proximal end 11 of the guidewire body is made of medical-grade metal, such as stainless steel or nickel-titanium alloy. This metal material endows the proximal end 11 with extremely high compressive strength and torsional stiffness. As the main pushing section of the guidewire body, this proximal end 11 metal structure can transmit the operator's axial thrust and rotational torque outside the body to the distal end 12 with a near 1:1 conductivity ratio, ensuring rapid response and precise control of the fiber optic guidewire in complex, narrow vascular networks.

[0058] Specifically, to ensure the structural smoothness and mechanical transition strength of the physical connection transition zone between the metal proximal end 11 and the polymer distal end 12 of the guidewire body, and to reduce the frictional resistance of the guidewire in the blood vessel, a polymer sheath 13 is continuously wrapped around the outer surface of the guidewire body. The outer diameter of the guidewire after being wrapped with the polymer sheath 13 is 0.8 to 1.2 mm.

[0059] Preferably, the outer coating of the guidewire body is made of the same polymer material as the distal 12 parts of the guidewire body. This continuous coating integrated outer surface design not only achieves uniformity of the guidewire's outer diameter along its entire length and eliminates the step effect at the junction of metal and non-metal, but also provides excellent electrical insulation and blood compatibility for the internal electric field drive network, ensuring absolute safety during multi-node electric field drive.

[0060] A sensing fiber 3 is installed in the central cavity 2 of the guidewire body. The sensing fiber 3 runs through the entire length of the guidewire, and its core function is to acquire, in real time and accurately, the strain distribution of the distal end 12 of the guidewire body in the complex vascular network and the contact force with the vascular endothelium.

[0061] The sensing fiber 3, serving as the sensing layer of the fiber optic guidewire in this embodiment, includes one or more core fibers extending axially along the central cavity 2, and one or more sensing nodes distributed on the core fibers. Specifically, strain sensing units are respectively provided at the precise axial positions corresponding to each controllable bending node; and a force sensing unit is provided at the farthest end 12 of the sensing fiber 3, i.e., immediately adjacent to the head of the guidewire body 1. The proximal end 11 of the sensing fiber 3 extends outward and is communicatively connected to an external controller.

[0062] Furthermore, each strain sensing unit and force sensing unit is configured to reflect optical signals with different spectral widths based on the incident light received at the near end 11, and based on the sensing fiber 3 along the curved distal side.

[0063] The conditions experienced by the head alter the characteristics of the reflected light signal.

[0064] The sensing fiber 3 uses Bragg fiber grating sensing technology, and its working principle is as follows:

[0065] During the advancement or large-angle path finding process in the book, when the distal end 12 of the guidewire body undergoes directional bending under the drive of the bending control component 4, or when the head of the guidewire body comes into physical contact with the vascular endothelium, the strain sensing unit or force sensing unit on the core fiber will generate corresponding mechanical deformation, causing the period of the grating inside the core fiber to change regularly, thereby causing the center wavelength of the reflected light in that area to drift.

[0066] The external controller receives and demodulates this wavelength drift signal at a high-frequency sampling rate, enabling precise and real-time calculation of the actual bending curvature (i.e., strain distribution) of each node of the guidewire and the magnitude of the normal contact force borne by the head. This provides reliable data criteria for the subsequent system to perform precise closed-loop pathfinding and trigger instantaneous physical softening and stress relief.

[0067] A bending control component 4 is provided at the head end of the guide wire body. For example... Figure 2 As shown, the bending control component 4 includes a first bending node and a second bending node distributed in series along the guide wire axis. This dual-node series structure is the physical basis for realizing large-angle superimposed bending under a small radius of curvature.

[0068] Each controllable bending node employs a coaxial nested design. Specifically, each controllable bending node is a phase change chamber 41 surrounding the central cavity 2. This phase change chamber 41 is a hollow annular closed capsule, with its inner wall tightly fitted to the outer wall of the central cavity 2, and its outer wall encased within the polymer sheath 13 of the guidewire body 1. The capsule wall of the phase change chamber 41 is made of thermoplastic polyurethane elastomer with high elongation at break, and the axial length of a single phase change chamber 41 is 10–15 mm.

[0069] On the outer surface of the phase change chamber 41, a partitioned electrode 42 responsible for applying the excitation field is attached. In this embodiment, the partitioned electrode 42 is arranged in a serpentine pattern on the outer surface of the phase change chamber 41 to buffer bending stress, and the total length of the serpentine segments is consistent with the length of the phase change chamber 41, covering the axial length of the phase change chamber 41. Each set of serpentine lines adopts a double-strand design, specifically two silver-plated copper wires with a diameter of 0.05 to 0.1 mm arranged in parallel, one as the positive electrode and the other as the negative electrode, forming a differential signal pair. The double-strand differential signal reduces external electromagnetic interference.

[0070] Specifically, the partitioned electrode 42 is physically isolated into at least two independent electrode regions along the axial direction of the phase change chamber 41. To prevent high-voltage short circuits from contacting blood, a 5-10 μm thick phenelzine biocompatible insulating layer is deposited on the surface of the partitioned electrode 42 by vapor deposition, and conductive contacts are provided.

[0071] Furthermore, a conductive film (ACF) is disposed on the surface of the guidewire body 1, and is connected to the partition electrodes 42 through designated conductive contacts. Specifically, four independent anisotropic conductive films with a thickness of 30-50 μm are attached to the surface of the guidewire body 1. These conductive films are connected to the partition electrodes 42, and each conductive film is connected to a set of partition electrodes 42 through designated conductive contacts, forming an independent conductive path for applying a set electric field to the phase change chamber 41. The ends of the conductive films extend to the proximal end 11 of the guidewire body and are connected to an external controller. The controller applies different voltages through different conductive films, and the current is transmitted through the partition electrodes 42 to the corresponding areas on the surface of the phase change chamber 41, forming an electric field intensity gradient.

[0072] Specifically, the conductive film is wrapped with a polymer sheath 13 to maintain insulation from the external environment.

[0073] To achieve a specific turning radius and span, the axial spacing between the first and second bending nodes is 10–15 mm. To enhance the physical support of this interval, the wall thickness of the central cavity 2 of the guidewire body 1 within this interval is designed to be slightly greater than its wall thickness inside the bending node, thereby forming a locally reinforced flexible transition zone.

[0074] In this embodiment, the controller applies a voltage of 0–90V through different partition electrodes 42. Under non-uniform electric field excitation, both the first bending node and the second bending node can independently achieve directional bending of 15–30°. When the second bending node is controlled to deflect by 30°, the preceding interval segment and the first bending node will also deflect by 30° as a whole. At this time, the first bending node will deflect again by 30° in the same direction based on the interval segment. Therefore, the final absolute bending angle of the guidewire's farthest end 12 relative to the initial straight axis is the algebraic sum of the deflection angles of each node.

[0075] The design of the septum acts as an extension arm, amplifying the lateral position of the guidewire tip. This allows the two 30° bends to be spaced further apart, forming a smooth arc with a large turning radius. This avoids sharp-angle creases caused by the first and second bending nodes being too close together, enabling extremely smooth crossing of wide vascular bifurcations.

[0076] Furthermore, if the controller applies differentiated voltages to the electrodes 42 of different quadrants of the first and second curved nodes respectively, for example, the first curved node deflects to the left and the second curved node deflects to the right, the guidewire body can also form a complex "S" shape in three-dimensional space, thereby conforming to various extremely tortuous vascular anatomy structures.

[0077] Specifically, an electroresponsive phase change fluid is encapsulated inside the phase change chamber 41. In this embodiment, the phase change fluid adopts a barium titanate-based electrorheological system, with nano-sized barium titanate (BaTiO3) as the dispersed phase and fluorosilicone oil as the continuous phase.

[0078] Specifically, the dispersed phase uses core-shell structured particles, with barium titanate particles of 50–100 nm in diameter as the core layer and a polyaniline (PANI) conductive polymer coated on the surface with a thickness of 5–10 nm as the shell layer. To overcome the additional bending stiffness of the central cavity 2 tube wall within the narrow annular phase change chamber 41, this embodiment employs a high solids content design, strictly controlling the mass ratio of the dispersed phase to the continuous phase between 2.2 and 3.5:1.

[0079] Furthermore, to offset the increase in background viscosity caused by high solids content, an ultra-lightweight fluorosilicone oil with a kinematic viscosity of only 10–30 cSt is selected as the continuous phase. This compound system ensures that the fluid in the phase change chamber 41 can still maintain a low viscosity of 0.2–0.3 Pa·s under the zero electric field state of normal propulsion, thereby ensuring that the distal end 12 of the guidewire has excellent flexibility.

[0080] More importantly, the dispersed phase is also doped with multi-walled carbon nanotubes (MWCNTs) at a mass fraction of 0.5%–2.0% of the total dispersed phase weight as a mechanical reinforcement phase. When a non-uniform strong electric field (e.g., 80 V / mm) is applied within the hollow annular confined space, the carbon nanotubes and core-shell polarized particles exhibit a synergistic polarization effect. The polarized carbon nanotubes interpenetrate and bridge the polarization chains of adjacent particles, constructing a three-dimensional cross-linked network with high structural strength. This microscopic composite network significantly enhances the shear strength and yield stress of the electrorheological fluid within the confined space, causing the apparent viscosity in local areas to rapidly increase to 2.5–3.5 Pa·s. This generates an asymmetric eccentric torque sufficient to overcome the physical stiffness of the inner and outer double-layer tube walls, efficiently driving the guide wire body 1 to complete extreme directional bending.

[0081] It should be noted that under the zero electric field state of normal propulsion, the phase change fluid in the phase change chamber 41 is a low viscosity fluid of 0.2 to 0.3 Pa·s, and the distal end 12 of the guidewire body maintains excellent flexibility.

[0082] When the guidewire head needs to be deflected or reach the bifurcation of a blood vessel, the external controller outputs a DC bias voltage to the partition electrode 42 at a specific location. For example, an 80V voltage is applied to the first location, and a 0V voltage is applied to the second location on the opposite side. At this time, a non-uniform electric field intensity gradient of 0 to 80V / mm is formed in the phase change chamber 41.

[0083] In the high electric field region of 80 V / mm, the polarized particles of the core-shell structure generate strong induced dipole moments due to interfacial polarization effects, arranging themselves into a dense chain-like structure along the electric field direction within milliseconds. This causes the fluid viscosity in this local region to rapidly increase to 2.5–3.5 Pa·s, a sharp increase in viscosity. Conversely, in the low electric field region of 0 V / mm, the viscosity remains low at 0.2–0.3 Pa·s.

[0084] The extremely large difference in regional viscosity within the same phase change chamber 41 causes the mechanical neutral axis of this local tube section to shift to the high viscosity side. Under the combined action of the axial thrust of the guidewire and the pre-tightening force of the sheath, this is transformed into an eccentric force. Furthermore, under the constraint of the polymer sheath 13, this is transformed into an asymmetrical bending moment, driving the guidewire body 1 to undergo precise directional bending towards the low viscosity side.

[0085] In this embodiment, the polymer sheath 13 of the guidewire body has a microgroove array laser-etched on the surface of the phase change chamber 41. Specifically, in the inner region of the preset bend between the first and second bend nodes, the axial spacing between adjacent microgrooves is 50–100 μm; in the outer region of the preset bend, the axial spacing between adjacent microgrooves is 100–150 μm. It should be noted that the circumferential surface of the phase change chamber 41 is equally angularly divided into regions A, B, C, and D. Regions A and C are the inner regions of the preset bend where the partition electrodes 42 are provided, while regions B and D are the outer regions of the preset bend where the partition electrodes 42 are not provided. That is, when controlling the directional bending of the guidewire head, it bends towards region A or region C. Through the smooth gradient of the microgroove spacing between 50 and 150 μm, an asymmetric flexibility gradient is constructed in the circumferential direction of the guidewire, significantly reducing the bending resistance in a specific direction.

[0086] Furthermore, the depth of the microgroove is 40% to 70% of the wall thickness of the polymer sheath 13, providing sufficient stress relief space for the directional bending of the phase change chamber 41, and protecting the integrity of the polymer sheath 13 to avoid failure of the internal electric field network or fluid leakage.

[0087] The aforementioned microgroove array design significantly reduces the physical resistance of the preset bending side, enabling the driving torque generated inside the phase change chamber 41 due to regional viscosity differences to be efficiently converted into a macroscopic directional bending of 30–60°. Furthermore, the microgrooves with specific spacing and cutting depth serve as effective stress relief units, absorbing the local compression and tensile strain generated by the polymer sheath 13 during large-angle bending. This not only significantly extends the fatigue life of the guidewire during high-frequency bending but also provides ample structural clearance space and absolute passive compliance guarantee when the "instantaneous physical softening and stress relief" mechanism is triggered by an emergency power failure.

[0088] In this embodiment, the controller is a medical navigation control terminal. The controller includes: an optical fiber demodulation unit, a logic operation unit, and a multi-channel high-voltage drive unit.

[0089] The controller and the guide wire body adopt a composite structure design with photoelectric separation.

[0090] In terms of optical connection, the proximal end 11 of the sensing optical fiber 3, which is inserted into the central cavity 2, extends out of the guide wire body and is connected to the optical fiber demodulation unit in the controller through a standard medical optical fiber connector. The optical fiber demodulation unit emits a broadband light source at a high frequency sampling rate of not less than 1000Hz and receives the reflected grating wavelength drift signal in real time, converting it into high-precision digital strain and contact force data.

[0091] In terms of electrical connection, the partition electrode 42 attached to the outside of each phase change chamber 41 extends to the proximal end 11 through a conductive film applied to the surface of the guide wire body and is connected to the high voltage drive unit in the controller, so that the controller can accurately address and output DC high voltage to each independent partition electrode 42.

[0092] To verify the phase change chamber 41 technology of this embodiment, a detailed comparative experiment is conducted below.

[0093] Experimental Group 1:

[0094] Fabricating the distal 12 sections of the optical fiber guidewire includes the following steps:

[0095] 1. Take 10g of barium titanate nanoparticles with a particle size of approximately 80nm, disperse them in 1L of deionized water, add 1g of aniline monomer, and ultrasonically disperse for 30min. Add 50mL of 0.1mol / L ammonium persulfate solution dropwise, and stir and polymerize at 3℃ for 2h to form a polyaniline conductive shell layer with a thickness of approximately 8nm on the barium titanate surface. After centrifugation and washing three times, dry under vacuum at 60℃ for 24h to obtain a core-shell structured dispersed phase (BaTiO3@PANI).

[0096] 2. Take 28g of the dispersed phase prepared above and add 10g of ultralight fluorosilicone oil with a viscosity of 20cSt (the mass ratio of dispersed phase to continuous phase is 2.8:1). Then, add 1.2% of the total weight of the dispersed phase multi-walled carbon nanotubes. Stir at 3000rpm for 2h using a high-shear disperser and degas under vacuum for 60min to obtain an electroresponsive phase change fluid.

[0097] 3. A hollow annular cylindrical cavity with an inner diameter of 0.5 mm, an outer diameter of 0.8 mm, and a length of 15 mm was prepared by thermoplastic polyurethane extrusion. Partition electrodes 42 were attached to the outer surface of the cavity, and an 8 μm pyrene insulating layer was deposited by vapor deposition. The aforementioned phase change fluid was quantitatively injected into the annular gap of the cavity and sealed to obtain a phase change chamber 41. Finally, it was fitted onto the outside of an inner tube containing a sensing optical fiber 3, an ACF conductive film was applied to its surface, and an outer sheath was wrapped around it. A microgroove array with a spacing of 80 μm was laser-etched on the pre-set curved surface to complete the fabrication of the distal 12 sections of the optical fiber guide wire.

[0098] Experimental group 2:

[0099] Based on Experiment 1, the only difference was that the mass ratio of the dispersed phase to the continuous phase was adjusted to 2.2:1, while the other parameters and preparation steps were exactly the same.

[0100] Experimental group 3:

[0101] Based on Experiment 1, the only difference was that the mass ratio of the dispersed phase to the continuous phase was adjusted to 3.5:1, while the other parameters and preparation steps were exactly the same.

[0102] Experimental group 4:

[0103] Based on Experiment 1, the only difference is that the doping amount of multi-walled carbon nanotubes was adjusted to 0.5% of the total weight of the dispersed phase, while other parameters and preparation steps were exactly the same.

[0104] Experimental group 5:

[0105] Based on Experiment 1, the only difference is that the doping amount of multi-walled carbon nanotubes was adjusted to 2.0% of the total weight of the dispersed phase, while other parameters and preparation steps were exactly the same.

[0106] Experimental group 6:

[0107] Based on Experiment 1, the only difference was that the continuous phase was replaced with an ultralight fluorosilicone oil with a viscosity of 10 cSt, while the other parameters and preparation steps were exactly the same.

[0108] Control group 1:

[0109] Based on experimental group 1, the difference is that no multi-walled carbon nanotubes were added, and only BaTiO3@PANI particles were retained.

[0110] Control group 2:

[0111] Based on Experiment 1, the difference is that the viscosity of the continuous phase is 100 cSt, the mass ratio of the dispersed phase to the continuous phase is adjusted to 1.5:1, and there are no multi-walled carbon nanotubes. Other parameters are exactly the same as the preparation steps.

[0112] Control group 3:

[0113] Based on Experiment 1, the difference is that the continuous phase was replaced with conventional 100cSt dimethyl silicone oil, while the other parameters and preparation steps were exactly the same.

[0114] Control group 4:

[0115] Based on experimental group 1, the difference is that the main dispersed phase directly uses pure BaTiO3 nanoparticles without a PANI shell.

[0116] The distal 12 sections of the optical fiber guidewires prepared in the experimental and control groups were subjected to the following tests:

[0117] Background viscosity (Pa·s): measured using a rotational rheometer (coaxial cylindrical clamp, 37℃, shear rate 100s). -1 The apparent viscosity of the fluid was measured at 0V / mm to assess the smoothness of the distal end 12 of the guidewire in the de-energized state.

[0118] Yield stress (kPa): The rheometer is connected to a high-voltage module and a non-uniform DC electric field of 80V / mm is applied at 37℃ to perform shear stress scanning. The stress value corresponding to the viscosity drop inflection point is taken as the dynamic yield stress to evaluate the shear driving force generated by the fluid polarization network.

[0119] Maximum bending angle and response time (ms): The distal 12 sections of the fiber optic guidewire are suspended and fixed proximally. An 80V bias voltage is applied to one side, and a high-speed camera (500fps) is used to record and measure the stable bending angle of a single node after overcoming the resistance of internal components, as well as the time required to reach 90% of the maximum angle.

[0120] The results of the comparative experiment are shown in the table below.

[0121] Table 1. Summary of Test Results

[0122]

[0123] As can be seen from Table 1 above, experimental groups 1-5, with their high solid content and the three-dimensional reinforcement network constructed by carbon nanotubes, generate strong yield stress, which can break through the bending stiffness of the inner and outer tube walls and complete the standard bending of 18-30° in a very short time.

[0124] In contrast, control groups 1 and 2 exhibited extremely weak yield stress. When faced with the additional resistance of the hollow annular structure, the driving force and resistance were almost equal, resulting in slow creep as the macroscopic deformation of the guidewire. Not only was the maximum bending angle small, but the time to reach this extreme value was also significantly prolonged, completely eliminating the agile maneuverability required for intraoperative pathfinding.

[0125] Control group 3 used conventional 100cSt dimethyl silicone oil. Although its final bending angle was acceptable, the high viscosity of the continuous phase resulted in enormous frictional forces from the rearrangement of polarized particles in the liquid phase, generating extremely severe fluid dynamic damping during bending. This led to a long response time, resulting in not only extremely poor normal compliance but also an inability to meet the emergency avoidance requirements of instantaneous physical force relief.

[0126] Control group 4 used pure barium titanate particles. Due to the lack of interfacial polarization gain from the PANI conductive shell, the charge migration and dipole response speeds were significantly reduced. The slow formation of polarization chains and the loose structure resulted in a severe lag in the macroscopic driving response time, further confirming that the core-shell structure is the underlying material basis for achieving high-strength, fast-response electric actuation.

[0127] In summary, the formulation combination specified in this embodiment not only solves the problem of insufficient driving force leading to angle limitation under hollow annular structure, but also completely eliminates the bending hysteresis phenomenon caused by critical driving force or excessive fluid damping from a dynamic perspective, truly achieving transient precise guidance within the range of 15 to 30°.

[0128] Example 2:

[0129] This embodiment provides a fiber optic guidewire. Addressing the technical problem of fiber optic guidewires easily slipping into the main vessel when crossing large-angle collateral vessels during vascular interventional procedures, this embodiment provides a three-node coordinated bending scheme.

[0130] In this embodiment, the bending control assembly 4 includes a first bending node, a second bending node, and a third bending node distributed in series along the axial direction of the guide wire body 1. The first axial distance between the first bending node and the second bending node is set to 10-15 mm; the second axial distance between the second bending node and the third bending node is set to 15-20 mm.

[0131] The circumferential surface of the phase change chamber 41 is equally divided into four regions: A, B, C, and D. Regions A and C are two pre-set curved surfaces arranged opposite each other. To meet the requirement of bidirectional bending with equal curvature, for the first, second, and third bending nodes, the outer surface of the polymer sheath 13 is etched with an array of microgrooves with an axial spacing of 50–100 μm between adjacent microgrooves in regions A and C, and with an array of microgrooves with an axial spacing of 100–150 μm between adjacent microgrooves in regions B and D.

[0132] Furthermore, regions A and C of the first, second, and third bending nodes are all equipped with partitioned electrodes 42. This structural design ensures that each bending node has a consistent physical shape and can generate bidirectional controllable bending under the drive of the controller.

[0133] In interventional vascular procedures, when faced with a large-angle collateral vessel bifurcation, the bending process of the fiber optic guidewire is as follows:

[0134] First, the external controller outputs a first bias voltage to the partition electrode 42 in region A of the first and second bending nodes, and a second bias voltage to the partition electrode 42 in region C. The first bias voltage is much greater than the second bias voltage. At this time, the electro-responsive phase change fluid in the corresponding region undergoes a phase change, and the local viscosity increases, generating asymmetric stiffness. This drives the tip of the guidewire body 1 to bend continuously towards the side where region C is located, guiding the distal end 12 of the guidewire body 1 across the vascular bifurcation and into the target collateral vessel.

[0135] Simultaneously or subsequently, the controller outputs a third bias voltage to the partition electrode 42 in region A of the third bending node, and a fourth bias voltage to the partition electrode 42 in region C, the fourth bias voltage being much greater than the third bias voltage. This voltage induces the third bending node to bend directionally towards region A.

[0136] The reverse bend of the third bending node causes the outer wall of the third bending node to abut against the inner wall of the main blood vessel on the opposite side, forming a reverse anchoring support point. The reverse force generated by this support point counteracts the radial outward turning moment generated at the bifurcation of the blood vessel when the axial thrust is applied to the proximal end 11, preventing the guidewire body 1 from slipping out of the inserted collateral blood vessel.

[0137] During this process, the sensing fiber 3, located inside the central cavity 2, acquires the contact force of the distal end 12 of the guidewire body 1 and the real-time strain distribution at the third bending node in real time. The controller calculates the wall support force at the node by comparing the difference between the actual strain and the theoretically controlled strain at the third bending node. Based on the above mechanical feedback data, the controller dynamically adjusts the fourth bias voltage input to the third bending node, thereby precisely controlling the contact torque of the third bending node against the inner wall of the main blood vessel, ensuring that the first and second bending nodes continue to advance deeper into the collateral vessels under stable force conditions.

[0138] In this embodiment, the fiber optic guidewire simplifies the manufacturing process by symmetrically arranging microgroove arrays and partitioned electrodes 42 in regions A and C of the first, second, and third bending nodes. This allows each node to achieve precise bidirectional deflection solely through differential control of the bias voltage. Furthermore, the specifically designed first and second axial spacings, while conforming to the bifurcation span of human blood vessels, create a flexible buffer zone for the guidewire body 1, effectively absorbing local stress during large-angle deformation and preventing fatigue damage to the polymer sheath 13.

[0139] Specifically, when traversing complex bifurcated vessels, the first and second bending nodes are inserted into the collateral vessels in the same direction, while the third bending node is driven to deflect in the opposite direction to abut against the inner wall of the main vessel, thus constructing a stable reverse anchoring structure. The radial support force generated by this structure effectively counteracts the outward turning torque converted from the axial thrust, preventing the guidewire body 1 from slipping out of the target vessel. Combined with the sensing fiber 3 located inside the central cavity 2, the controller can dynamically fine-tune the bias voltage based on real-time mechanical feedback. This precisely controls the abutment torque to maintain anchoring stability while avoiding mechanical damage to the vascular intima, achieving a high degree of balance between high-angle pathfinding efficiency and interventional safety.

[0140] Example 3:

[0141] like Figure 3 As shown, this embodiment provides a method for controllable bending of the distal end 12 of an optical fiber guide wire, based on the optical fiber guide wire of Embodiment 1 or Embodiment 2. The method specifically includes the following steps:

[0142] Step S1: Perform surgical path planning to determine the target route and expected bending parameters of the guidewire body 1 in the vascular network;

[0143] Step S2: When the distal end 12 of the guidewire body 1 reaches the vascular branch, a differentiated voltage is output to the specific partition electrode 42 of the specific bending node according to the surgical path plan, driving the guidewire body 1 to bend in a specific direction.

[0144] Step S3: Based on the mechanical feedback transmitted by the sensing fiber 3, dynamically adjust the output voltage of the controller to a specific controllable bending node to automatically adjust the bending angle or achieve physical stress relief.

[0145] The distal 12 controllable bending method of this embodiment deeply integrates preoperative three-dimensional path planning with intraoperative phase change fluid electric field control and fiber optic mechanical sensing. When the guidewire reaches a complex vascular bifurcation, it can not only perform precise electro-driven directional path finding strictly according to the preset plan, but also dynamically correct the bending posture using real mechanical feedback or soften and retract instantly at dangerous moments. It overcomes the defects of existing guidewires that blindly seek paths in extremely tortuous blood vessels, are prone to deviating from the target blood vessel, or cause mechanical damage to the blood vessel. It greatly improves the accuracy of path execution and the absolute safety of the vascular intima in high-difficulty interventional surgeries.

[0146] The steps of the controllable bending method of the distal end 12 in this embodiment will be described in detail below.

[0147] In step S1, before the actual interventional surgery is performed, vascular imaging data of the patient's lesion area is acquired to construct a digital three-dimensional vascular model. Based on the set lesion target points, a detailed surgical path is planned on the three-dimensional vascular model, and the optimal vascular intervention channel is selected and determined.

[0148] For each vascular branch or bifurcation point that must be crossed on the optimal vascular intervention channel, the spatial turning radius and deflection direction required for the guidewire body 1 to pass smoothly are calculated in advance, and these geometric data are converted into the expected output voltage distribution (such as DC bias voltage of 0-90V) for the specific bending node, so as to establish a benchmark for subsequent precise intraoperative guidance.

[0149] In step S2, during the interventional procedure, the operator advances the guidewire body 1 inward along the defined vascular pathway. When the distal end 12 of the guidewire body 1 reaches the specific vascular branch or bifurcation position marked in the surgical path planning, the external controller accurately addresses and outputs a set differential bias voltage to the partition electrode 42 located in a specific position at the specific bending node according to the preset expected bending parameters.

[0150] The non-uniform electric field instantaneously excites the phase change fluid in the corresponding region to undergo a phase change, resulting in a sharp increase in local viscosity (for example, a rapid jump from a low viscosity state of 0.2 to 0.3 Pa·s to a high viscosity state of 2.5 to 3.5 Pa·s). This creates significant asymmetric stiffness inside the guidewire body 1, which in turn drives the guidewire body 1 to undergo precise directional bending towards the planned target vascular branch (e.g., a single node independently achieves a deflection of 15 to 30°, while multiple nodes work together to achieve a deflection of 30 to 60°), guiding the guidewire smoothly into the target branch.

[0151] In step S3, during the dynamic process of the guidewire body 1 bending in a specific direction and probing deep into the target blood vessel branch, the sensing optical fiber 3 inserted inside the central cavity 2 undergoes mechanical deformation, thereby sensing the real contact force between the distal end 12 of the guidewire body 1 and the inner wall of the blood vessel in real time, and continuously transmitting this mechanical feedback back to the controller in the form of an optical signal.

[0152] Furthermore, the controller performs high-speed demodulation and comparison of the mechanical feedback at a high-frequency sampling rate of no less than 100Hz. Specifically:

[0153] If the contact force distribution indicates that the actual path-finding trajectory deviates from the expected one or encounters a slight local obstruction, the controller adjusts the voltage input to the specific zone electrode 42 to change the regional viscosity difference of the phase change fluid, thereby automatically increasing or decreasing the bending angle of the guide wire body 1 to smoothly correct the travel path.

[0154] If the acquired contact force value increases suddenly and approaches the preset safety limit threshold, the controller will cut off instantly (e.g., reduce the voltage to 0V) or significantly reduce the output voltage, so that the phase change fluid will dissociate instantly and restore the low viscosity background state of 0.2 to 0.3 Pa·s, eliminating the internal asymmetric stiffness, causing the distal end 12 of the guide wire body 1 to soften instantly, so as to achieve complete physical unloading.

[0155] This step introduces a voltage dynamic intervention and instantaneous softening and stress relief mechanism based on real-time optical sensing. It utilizes the microscopic deformation data of the sensing fiber 3 to adjust the macroscopic mechanical state of the phase change fluid at high frequency, solving the local deviation that may exist between the preset static path and the dynamic vascular environment. Compared with existing guidewires that rely solely on fixed structures or single manipulation, this method endows the guidewire with intelligent risk avoidance capabilities, such as automatic adjustment when encountering resistance and instantaneous softening when encountering danger. This eliminates the risk of vascular dissection or puncture caused by forced pushing and reduces the surgical safety risk.

[0156] Example 4:

[0157] This embodiment takes the optical fiber guidewire of Embodiment 1 as an example to propose a method for fabricating an optical fiber guidewire, including the following steps:

[0158] Step A1: Prepare an independent phase change chamber 41 and encapsulate the phase change fluid;

[0159] Step A2: Sequentially install and fix at least two phase change chambers 41 onto the preset positions of the polymer distal end 12 pipe;

[0160] Step A3: Splice the distal end 12 tube with the proximal metal 11 tube to form a guide wire body 1 with a central cavity 2 inside;

[0161] Step A4: Insert the sensing fiber 3 into the central cavity 2 and calibrate the position of the sensing node;

[0162] Step A5: Lay out a conductive film and establish an electrical connection with the partition electrode 42;

[0163] Step A6: Cover with a polymer sheath and etch a microgroove array in the preset bending area.

[0164] The preparation method of this embodiment will be described in detail below.

[0165] In step A1, the preparation of the phase change chamber 41 specifically includes:

[0166] A11. A hollow annular cavity is made of thermoplastic polyurethane elastomer material through a microtube extrusion process.

[0167] A12. On the outer surface of the hollow annular cavity, silver-plated copper wires are attached in a predetermined arrangement to form partitioned electrodes 42. A biocompatible insulating layer is prepared on the surface of the partitioned electrodes 42 by vapor deposition. At the same time, exposed contacts for electrical connection are reserved at the proximal end 11 of the partitioned electrodes 42.

[0168] A13. The prepared phase change fluid is quantitatively injected into the cavity, and then the injection port is sealed by ultrasonic welding to obtain an independent phase change chamber 41.

[0169] In step A2, the guidewire body 1 is divided into two sections: the distal end 12 is a hollow tube made of polymer material, and the proximal end 11 is a hollow tube made of medical metal material.

[0170] Further, at least two phase change chambers 41 prepared in step A1 are sequentially fitted and fixed to a preset position on the outer surface of the distal 12 pipe, and the axial distance between adjacent phase change chambers 41 is controlled to be 10-15 mm.

[0171] This step introduces a method of independently pre-installing a closed phase change chamber 41 on the distal end 12 of the tube, which effectively avoids the risk of tolerance accumulation caused by directly machining a small liquid cavity on the entire long guide wire, and ensures the absolute accuracy and flexible transition of the axial spacing between multiple nodes. Compared with the existing technology where the overall groove is opened and liquid is poured on the guide wire body 1, which is prone to a cliff-like drop in structural strength, this step improves the overall structural integrity and bending fatigue life of the distal end 12 of the guide wire.

[0172] In step A3, the proximal end 11 port of the pre-installed distal end 12 tube in the phase change chamber 41 is coaxially aligned with the distal end 12 port of the proximal end 11 tube, and the splice is fixed by medical adhesive or hot melt process, thereby forming a complete guidewire body 1 with a central cavity 2 that runs through the entire length.

[0173] In step A4, the sensing fiber 3, with the grating sensing nodes inscribed on it, is inserted from near to far into the central cavity 2 inside the complete guide wire body 1. With the assistance of an optical monitoring device, the axial position of the sensing fiber 3 is finely adjusted to ensure that each sensing node and the corresponding phase change chamber 41 are in the same axial cross section. After accurate positioning, both ends of the central cavity 2 are sealed and filled with dry inert gas.

[0174] In step A5, an anisotropic conductive film is axially attached to the outer surface of the guide wire body 1. Using a precision thermo-pressing process, the distal end 12 of the conductive film is independently electrically connected to the partition electrodes 42 on the surface of each phase change chamber 41 to construct a high-voltage drive path from the distal end 12 to the proximal end 11.

[0175] In step A6, a layer of polymer material is continuously extruded and coated onto the outside of the assembled guide wire body 1 and phase change chamber 41 to form a polymer sheath with uniform thickness and full-length insulation. Subsequently, a femtosecond laser device is used to precisely ablate the surface of the polymer sheath facing the preset bending direction to form a microgroove array with a smooth gradient in depth and axial spacing, thus obtaining a complete optical fiber guide wire.

[0176] This step involves using laser etching to create a gradient array of microgrooves after the sheath is applied. Laser ablation can precisely remove the outer material without physical contact, constructing an asymmetric flexibility gradient on the surface of the guidewire body 1 without damaging the fragile internal electric field network. This weakens the physical stiffness resistance of the preset bending side and provides ample space for stress release. Compared to the traditional guidewire with a uniform stiffness distribution in the circumferential direction, which severely limits the bending angle and easily causes sheath tearing, this step releases the eccentric torque generated by the internal phase change fluid, ensuring the structural smoothness and absolute safety of the guidewire body 1 when it undergoes large-angle extreme deflection.

[0177] Based on the preferred embodiments of the present invention described above, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. An optical fiber guidewire, characterized in that, include: The guidewire body has an axially extending central cavity inside. A sensing optical fiber, disposed inside the central cavity, is used to acquire the contact force and strain distribution at the distal end of the guidewire body; and A bending control assembly is disposed at the distal end of the guidewire body and includes at least two controllable bending nodes spaced apart along the axial direction; each controllable bending node includes a phase change chamber surrounding the central cavity and multiple partitioned electrodes attached to the phase change chamber; the phase change chamber is encapsulated with an electroresponsive phase change fluid; It also includes an externally configured controller that communicates and is electrically connected to the sensing optical fiber and each of the partition electrodes; the controller is configured to: output voltage to a specific partition electrode to excite the electro-responsive phase change fluid in the corresponding area to undergo a phase change to generate asymmetric stiffness, drive the guide wire body to bend in an directional manner; and dynamically adjust the output voltage of the partition electrode according to the comparison result of the contact force and the preset safety threshold.

2. The optical fiber guidewire according to claim 1, characterized in that, Each phase change chamber is a hollow annular closed capsule, with its inner wall tightly fitted to the outer wall of the central cavity, and its outer wall encased in a polymer sheath of the guidewire body; the capsule wall of the phase change chamber is made of thermoplastic polyurethane elastomer. The partitioned electrodes are arranged in a serpentine pattern on the outer surface of the phase change cavity, and each group of the serpentine lines adopts a dual-strand differential signal line design containing one positive electrode and one negative electrode. The partitioned electrodes are physically isolated into at least two independent electrode regions along the axial direction of the phase change chamber, and their surfaces are covered with a biocompatible insulating layer and have pre-reserved conductive contacts.

3. The optical fiber guidewire according to claim 1, characterized in that, The electroresponsive phase change fluid comprises a dispersed phase and a continuous phase; the dispersed phase consists of core-shell structured particles with barium titanate particles as the core layer and polyaniline conductive polymer coated on the surface as the shell layer; the continuous phase is ultralight fluorosilicone oil. The mass ratio of the dispersed phase to the continuous phase is 2.2 to 3.5:1; The dispersed phase is also doped with multi-walled carbon nanotubes at a mass fraction of 0.5% to 2.0% of the total weight of the dispersed phase as a mechanically reinforcing phase.

4. The optical fiber guidewire according to claim 1, characterized in that, The guidewire body is divided into two sections along the axial direction, with the distal end made of medical polymer material and the proximal end made of medical metal material. The outer surface of the guidewire body is continuously covered with a polymer sheath.

5. The optical fiber guidewire according to claim 2, characterized in that, The polymer sheath of the guidewire body has a microgroove array etched on the surface corresponding to the phase change chamber; In the inner region of the preset bend, the axial spacing between adjacent microgrooves is 50–100 μm; in the outer region of the preset bend, the axial spacing between adjacent microgrooves is 100–150 μm.

6. The optical fiber guidewire according to claim 1, characterized in that, The sensing fiber employs Bragg fiber grating sensing technology and includes a core fiber extending along the axial direction of the central cavity and sensing nodes distributed thereon. A strain sensing unit is provided at the exact axial position corresponding to each of the controllable bending nodes, and a force sensing unit is provided at the position adjacent to the head of the guide wire body.

7. The optical fiber guidewire according to claim 1, characterized in that, The bending control assembly includes a first bending node, a second bending node, and a third bending node that are connected in series along the axial direction of the guide wire body. The first axial distance between the first bending node and the second bending node is 10-15 mm, and the second axial distance between the second bending node and the third bending node is 15-20 mm. The third bending node is configured to bend in the opposite direction to the first and second bending nodes under the drive of the controller, so that the outer wall of the third bending node abuts against the inner wall of the main blood vessel to form a reverse anchoring support point.

8. The optical fiber guidewire according to claim 1, characterized in that, A conductive film is attached to the surface of the guidewire body; each of the conductive films is connected to a set of partition electrodes through a designated conductive contact, forming an independent conductive path and extending to the proximal end of the guidewire body to connect with the controller.

9. A method for controllable bending of the distal end of an optical fiber guidewire according to any one of claims 1-8, characterized in that, Includes the following steps: S1. Perform surgical path planning to determine the target route and expected bending parameters of the guidewire body in the vascular network; S2. When the guidewire reaches the vascular branch at the farthest end of the guidewire body, a differential voltage is output to the specific zone electrode of the specific bending node according to the surgical path plan, driving the guidewire body to bend in a specific direction. S3. Based on the mechanical feedback transmitted through the sensing fiber, the controller dynamically adjusts the output voltage to specific controllable bending nodes to automatically adjust the bending angle or achieve physical stress relief.

10. The method for controllable bending of the distal end of an optical fiber guidewire according to claim 9, characterized in that, In step S3, if the contact force distribution indicates that the actual pathfinding trajectory deviates from the expected one or encounters a slight local obstruction, the controller adjusts the voltage input to the specific partition electrode to change the regional viscosity difference of the phase change fluid, thereby automatically adjusting the bending angle of the guidewire body. If the obtained contact force value increases sharply and approaches the preset safety limit threshold, the controller instantly cuts off or significantly reduces the output voltage, causing the phase change fluid to instantly return to its low viscosity background state and eliminate internal asymmetric stiffness, resulting in the distal end of the guide wire body instantly softening to achieve physical force relief.

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