Composite micro guide wire and manufacturing method thereof

Abstract

The invention relates to the technical field of medical instruments, and discloses a composite micro guide wire and a manufacturing method thereof.The inner core body of the micro guide wire is formed by stainless steel (or novel stainless steel)-nickel titanium in a composite mode, and an inner core comprises a conveying section (supporting section), a transition section (transition section) and a head end soft section which are arranged in sequence; a platinum core nickel-titanium alloy wire is tightly wound on the head end soft section, the inner core and the outer layer of the platinum core nickel-titanium alloy wire are integrally wrapped by TPU, the surface of the near section of the TPU layer is coated with a hydrophobic coating, and the surface of the far section of the TPU layer is coated with a hydrophilic coating. The micro guide wire is manufactured through the following steps of material preparation, inner core positioning, contact part compounding, platinum core nickel-titanium alloy wire winding and fixing, TPU coating and coating. The surface of the micro guide wire is smooth, the performance of the transition section is good, the head end is soft, the soft section of the head end is tightly wound by the platinum core nickel-titanium alloy wire, and an ideal developing effect is achieved.

Description

Technical Field

[0001] The present invention relates to the field of medical devices, and in particular to a composite micro-guidewire and a manufacturing method thereof. Background Art

[0002] With the aging of the population in my country, the incidence of vascular diseases is getting higher and higher. In order to diagnose and treat vascular diseases, minimally invasive interventional surgery such as vascular surgery, cardiology, neurosurgery, thoracic surgery, and interventional surgery has become a general trend. In the field of minimally invasive intervention, guidewires play the role of guide rails and rapid positioning for various interventional surgeries during interventional treatment, and are an indispensable and important supporting product in interventional surgery.

[0003] The guide wires on the market are mainly stainless steel spring guide wires, which are composed of two parts: the inner core of the micro guide wire and its welded spring. The stainless steel wire is straightened and ground once to form the inner core. The spring part is formed by winding fine stainless steel wire through a precision spring machine, and then welded to the inner core after cleaning. However, this kind of guide wire is not elastic enough, and its front end is easily bent and deformed, and cannot provide sufficient support to support the pushing of the guide wire;

[0004] There are also stainless steel-nickel-titanium composite guidewires on the market, which are roughly divided into two types. One type consists of a core wire and a protective sheath. The core wire is mostly stainless steel or nickel-titanium alloy, and the protective sheath is mostly polymer material, coil or metal tube. Although this method can improve the flexibility of the transition section of the microguidewire, its tubular structure has very limited efficiency in transmitting microguidewire force, especially for the improvement of torsion control. The structure of the metal tube will also cause the microguidewire to have insufficient anti-bending properties, resulting in difficulty in achieving the expected effects in pushing and passing properties during surgery, increasing the probability of damaging blood vessels and adding uncertainty to doctors' accurate and effective surgical treatment. The other type of microguidewire is a core wire composed of two materials, stainless steel wire and nickel-titanium wire. The stainless steel wire and the nickel-titanium wire are connected in the protective tube by welding or bonding. Stainless steel wire improves the support of the proximal end of the microguidewire, and nickel-titanium alloy improves the flexibility of the distal end of the microguidewire, which is more conducive to passing through tortuous vascular pathways. However, as different materials, stainless steel and nickel-titanium have obvious differences in material composition and properties. It is difficult to achieve a perfect transition between the two materials with current welding or bonding technology. The performance near the connection point is difficult to meet expectations, which directly affects the pushability and torsionability of the microguidewire from the proximal end to the distal end, resulting in increased difficulty in microguidewire operation. Moreover, the connection of the core wire is highly dependent on the welding / bonding process. When there is a lack of welding / glue, the core wire connection point may break during use, leading to serious safety issues.

[0005] Researching and inventing more complete and accurate controllable guidewires is an urgent need of frontline chief physicians, and further improving the safety and comprehensive performance of guidewires is the unremitting pursuit of device developers. Summary of the invention

[0006] 2. In order to overcome the above-mentioned deficiencies of the prior art, the present invention provides a composite micro guidewire, comprising:

[0007] The inner core is composed of a stainless steel segment and a nickel-titanium segment through a special structure and process. The inner core is composed of a conveying segment, a gradient segment and a head soft segment from the proximal end to the distal end. The head soft segment is wound with a platinum-core nickel-titanium alloy wire;

[0008] A TPU layer is coated on the inner core and the outer layer of the platinum core nickel-titanium alloy wire. The near section of the surface of the TPU layer is coated with a hydrophobic coating, and the far section of the surface of the TPU layer is coated with a hydrophilic coating.

[0009] Furthermore, the inner core is a stainless steel-nickel-titanium composite structure, and its composite position can be located at the far end of the conveying section or at the gradient section.

[0010] Furthermore, the stainless steel-nickel-titanium composite structure is characterized in that the length of the composite section of the stainless steel-nickel-titanium composite structure is about 20-60 mm.

[0011] Furthermore, the stainless steel-nickel-titanium composite structure can be riveted, threaded, or nested, and after composite fixation, it is subjected to high-temperature heat treatment in a fixed mold cavity (temperature is about 1200-1400°C).

[0012] Furthermore, there are two types of mold cavities used for fixing, one is a straight cavity in the conveying section, and the other is a tapered cavity located in the transition section.

[0013] Furthermore, the heat treatment process after the composite can adjust the hardness and elastic modulus of the composite section of nickel-titanium-stainless steel wire by controlling the temperature and time.

[0014] Furthermore, the length of the inner core is 1200-1800 mm, of which the length of the stainless steel section is 800-1500 mm.

[0015] Furthermore, the diameter of the conveying section is about 0.3-0.5 mm.

[0016] Furthermore, the length of the gradient section is 120 mm to 200 mm.

[0017] Furthermore, the length of the soft segment at the head end is 20 to 60 mm, and the diameter of the soft segment at the head end is 0.08 to 0.2 mm.

[0018] Furthermore, the winding length of the platinum core nickel-titanium alloy wire is 20 to 60 mm, the diameter is 0.03 to 0.05 mm, and the platinum content of the platinum core nickel-titanium alloy wire is about 10% to 20%.

[0019] Furthermore, the platinum core nickel-titanium alloy wire and the core wire are coaxial structures.

[0020] Furthermore, the platinum core nickel-titanium alloy wire is formed by winding a single wire or multiple wires in parallel, the proximal end of the platinum core nickel-titanium alloy wire is fixed to the distal end of the gradient section, and the distal end of the platinum core nickel-titanium alloy wire is fixed to the distal end of the nickel-titanium section.

[0021] Furthermore, the TPU layer is a thermoplastic elastic layer, which is formed by extrusion through a mold.

[0022] Furthermore, the hydrophobic coating material is one of polytetrafluoroethylene (PTFE), silicone resin, dihydrofluorescein, and polyurethane acrylic coating.

[0023] Furthermore, the hydrophilic coating material is one of polyvinyl pyrrolidone (PVP) and polyacrylamide (PAM).

[0024] In order to solve the technical defects of the composite micro-guidewire method in the prior art, the present invention provides a method for manufacturing a composite micro-guidewire for interventional treatment, comprising the following steps:

[0025] (1) Material preparation:

[0026] A stainless steel core wire (composite part has been processed and formed) with a length of 800 to 1500 mm and a nickel-titanium alloy wire formed by melting and casting;

[0027] 1 nickel-titanium alloy core wire with a length of 300-400 mm (the composite part has been processed and formed, the transition section has been formed, and the soft section has been formed);

[0028] (2) Inner core positioning: The stainless steel segment and the nickel-titanium segment are fixed in the fixture respectively, and the composite parts are overlapped together to prepare for composite;

[0029] (3) Contact part compounding: The molded structure is assembled together by a fixture, and then the composite part is fixed in the mold cavity for high-temperature heat treatment (temperature is about 1200-1400℃).

[0030] (4) Winding and fixing of developing wire: fix one end of the platinum core nickel-titanium alloy wire to one end of the soft section at the head end by welding or gluing, and then use an automated winding machine to evenly and tightly wind the gold wire around the soft section at the head end, with the winding length controlled within the range of 20 to 60 mm;

[0031] (5) TPU coating: the inner core component in step 4 is extruded through an extruder die to coat the inner core component with TPU;

[0032] (6) Coating: After the guide wire in step 5 is naturally cooled to room temperature, a hydrophobic coating is first applied to the proximal section by ultrasonic spraying technology. After solidification, a hydrophilic coating is applied by dipping or spraying.

[0033] Compared with the prior art, the beneficial effects of the present invention are:

[0034] The inner core of the composite micro-guidewire of the present invention is compositely formed of stainless steel and nickel-titanium alloy. The stainless steel wire provides sufficient support for the micro-guidewire, and the nickel-titanium alloy improves the flexibility of the distal end of the micro-guidewire, making it more conducive to passing through tortuous vascular pathways. The high-temperature heat treatment of the composite fixed mold cavity allows a smooth transition between the two materials, giving the guidewire excellent pushing performance, supporting performance and controllability. The nickel-titanium alloy head end makes the guidewire head end softer, enhances the flexibility of the head end, and improves durability. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is the overall structure diagram of the micro guide wire of the present invention.

[0036] Figure 2 It is a structural diagram of the composite position in the conveying section of the present invention.

[0037] Figure 3 It is a structural diagram of the composite position in the gradient section of the present invention.

[0038] Figure 4 It is a structural diagram of a spiral composite method in the present invention.

[0039] Figure 5 The composite form of the present invention is a spiral structure diagram of a partial nickel-titanium segment guide wire.

[0040] Figure 6 This is a structural diagram of the composite method in the present invention in the form of rivets.

[0041] Figure 7 This is a structural diagram of a nested composite method in the present invention.

[0042] Figure 8 This is a structural diagram of the invention in which the guide wire is spirally compounded and then subjected to high-temperature treatment in a mold cavity when the compounding position is in the conveying section.

[0043] Fig. 9 This is a structural diagram of the invention in which the guide wire is spirally compounded and then subjected to high-temperature treatment in a mold cavity when the compounding position is in a gradient section.

[0044] Fig.10 It is a structural diagram of the platinum core nickel-titanium alloy wire in the invention when it is wound in the soft section.

[0045] Fig.11 It is a path diagram of the double-layer winding of the platinum core nickel-titanium alloy wire in the soft section in the invention.

[0046] Fig.12 This is a diagram showing the effect of the soft section of the platinum core nickel-titanium alloy wire being wound in double layers in the invention.

[0047] In the figure: 1. core wire, 101. stainless steel segment, 102. nickel-titanium segment, 11. conveying segment, 12. gradient segment, 13. soft segment, 2. platinum core nickel-titanium alloy wire, 3. TPU layer, 4 hydrophobic coating, 5. hydrophilic coating, 6. heat treatment mold. DETAILED DESCRIPTION

[0048] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings so that the advantages and features of the invention can be more clearly expressed, thereby making a clearer and more definite definition of the protection scope of the present invention.

[0049] Refer to the attached Figure 1 The present invention discloses an interventional medical composite micro-guidewire, comprising an inner core 1, wherein the inner core 1 is compositely formed of stainless steel and nickel-titanium materials, wherein the main body of the core wire 1 is composed of a conveying section 11, a gradient section 12, and a soft head section 13 from the proximal end to the distal end, wherein the soft section 13 is wound with a platinum core nickel-titanium alloy wire 2, wherein the outer layer of the inner core 1 and the platinum core nickel-titanium alloy wire 2 is coated with a TPU layer 3, wherein the proximal section of the surface of the TPU layer 3 is coated with a hydrophobic coating 4, and the distal section of the surface of the TPU layer 3 is coated with a hydrophilic coating 5; the distal section of the inner core 1 is a nickel-titanium alloy wire 2, and the length of the nickel-titanium alloy wire 2 is 300 to 400 mm, wherein the nickel-titanium alloy wire 2 not only has a unique shape memory function, but also has excellent characteristics such as wear resistance, corrosion resistance, high damping and superelasticity, etc., which provide the micro-guidewire with excellent pushing performance, supporting performance and bending performance, and is more conducive to passing through a tortuous vascular path.

[0050] like Figure 4 , 5 As shown: the position where the stainless steel segment and the nickel-titanium core wire 2 are composited is tightly fitted in a spiral manner, and then in a high-precision mold, the temperature and time are controlled to make the two materials fully contact and fit. Correspondingly, the nickel-titanium material has a lower melting point, so that the final structure of the composite position in the mold cavity is more stable and the performance is more in line with the requirements.

[0051] During high-temperature compounding, filling the mold cavity with material so that there are no missing materials and cavities in the compounded structure, or adding a fixed ring structure at the edge or middle of the compounding position to fully ensure the strength and reliability of the compound section is also a method to ensure the effective implementation of the plan.

[0052] like Figure 2 , 3As shown, in the technical solution of the present invention, the composite section can be in the delivery section of the core wire 1 or in the gradient section of the core wire 1, and is specifically designed according to the functions and requirements of the micro guidewire; for those with higher requirements for mid- and far-end passability and anti-kinking, the composite section can be placed at the distal end of the delivery section, so that the guidewire has stronger passability and anti-deformation ability. For those with higher requirements for far-end pushing force, the composite section can be placed at the distal end of the gradient section, so that it can exert better pushing performance.

[0053] The composite position may be composited in various ways, such as rivet results, nesting, etc. Figure 6 , 7 As shown; it’s just that the contact situations of the two segments are different. In essence, they are in full contact and wrapping with each other. The key point is the high-temperature heat treatment after compounding. By controlling the two variables of temperature and time, the composite segments after heat treatment can show different properties, which is convenient for transmitting thrust and torque after molding.

[0054] As an important part of the present invention, the mold cavity used for high temperature heat treatment varies depending on the composite position. The composite cavity of the conveying section is equivalent to the outer diameter of the core wire of the conveying section, such as Figure 8 As shown; the cavity of the gradient section composite is highly matched with the variable diameter aperture corresponding to the core wire diameter change, such as Fig. 9 As shown; at the same time, in the positioning before the composite heat treatment and the fixing process during the heat treatment, the fixing devices on both sides of the heat treatment chamber are also equally important. It makes the two ends of the stainless steel-nickel titanium fit tightly and firmly keep relatively still, which plays a very critical role in the effect of the heat treatment;

[0055] Likewise, during the high temperature compounding process, the mold cavity needs to maintain high pressure and a relatively closed state to fully achieve the purpose of compounding the two materials; after the high temperature compounding, the reprocessing of the surface of the compounding position is also a component of the present invention.

[0056] The soft section is wound with a platinum core nickel titanium alloy wire, such as Fig.10 As shown, the platinum core nickel-titanium alloy wire is formed by winding a single or multiple metal wires side by side, the proximal end of the platinum core nickel-titanium alloy wire 2 is fixed to the distal end of the gradient segment 12, and the distal end is fixed at a position close to the distal end of the nickel-titanium segment 12, giving full play to its imaging function, and providing full assistance for the precise positioning of the guide wire during surgery;

[0057] The winding of the platinum core nickel-titanium alloy wire of the development structure of the present invention can be designed as a single wire or multiple wires; the single wire structure can be tightly wound, while ensuring the development performance, fully ensuring the transition of the distal end performance of the guide wire; the multi-wire parallel structure can make the distal end of the guide wire have higher strength and better elasticity, and the torque resistance and fatigue resistance are also greatly enhanced; at the same time, the winding can also be carried out according to the inner layer and the outer layer, such as Fig.12 As shown, it can also meet the requirements of high strength and high elasticity, giving full play to the advantages of this design method.

[0058] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A composite micro guidewire, characterized in that: include: The inner core is composed of a stainless steel segment and a nickel-titanium segment through a special structure and process. The inner core is composed of a conveying segment, a gradient segment and a head soft segment from the proximal end to the distal end. The head soft segment is wound with a platinum-core nickel-titanium alloy wire; A TPU layer is coated on the inner core and the outer layer of the platinum core nickel-titanium alloy wire. The near section of the surface of the TPU layer is coated with a hydrophobic coating, and the far section of the surface of the TPU layer is coated with a hydrophilic coating.

2. A composite micro guidewire according to claim 1, characterized in that: The inner core is a stainless steel-nickel-titanium composite structure, and the composite section can be located at the far end of the conveying section or at the gradient section.

3. A composite micro guidewire according to claim 2, characterized in that: The length of the composite section is about 20-60 mm.

4. A composite micro guidewire according to claim 3, characterized in that: The stainless steel-nickel-titanium composite structure is riveted or screwed together or nested, and then subjected to high-temperature heat treatment (temperature is about 1200-1400° C.) in a fixed mold cavity.

5. A composite micro guidewire according to claim 2, characterized in that: The inner core is a stainless steel-nickel-titanium composite structure with a length of 1200 to 1800 mm, of which the stainless steel section is 800 to 1500 mm; the diameter of the conveying section is approximately 0.3 to 0.5 mm, and the length of the gradient section is 120 to 200 mm; the length of the soft section at the head end is 20 to 60 mm, and the diameter of the soft section at the head end is 0.08 to 0.2 mm.

6. A composite micro guidewire according to claim 1, characterized in that: The platinum core nickel-titanium alloy wire has a winding length of 20 to 60 mm and a diameter of 0.03 to 0.05 mm. The platinum content of the platinum core nickel-titanium alloy wire is approximately 10% to 20%. The platinum core nickel-titanium alloy wire and the core wire are coaxial structures. The platinum core nickel-titanium alloy wire is formed by winding a single wire or multiple wires side by side. The proximal end of the platinum core nickel-titanium alloy wire is fixed to the distal end of the gradient section, and the distal end of the platinum core nickel-titanium alloy wire is fixed to the distal end of the nickel-titanium section.

7. A composite micro guidewire according to claim 1, characterized in that: The TPU layer is a thermoplastic elastic layer, which is formed by extrusion through a die.

8. A composite micro guidewire according to claim 1, characterized in that: The hydrophobic coating material is one of polytetrafluoroethylene (PTFE), silicone resin, dihydrofluorescein, and polyurethane acrylic coating.

9. A composite micro guidewire according to claim 1, characterized in that: The hydrophilic coating material is one of polyvinyl pyrrolidone (PVP) and polyacrylamide (PAM).

10. A method for manufacturing a composite micro-guidewire as claimed in claims 1 to 9, characterized in that: The steps include: (1) Material preparation: A stainless steel core wire (composite part has been processed and formed) with a length of 800 to 1500 mm and a nickel-titanium alloy wire formed by melting and casting; 1 nickel-titanium alloy core wire with a length of 300-400 mm (the composite part has been processed and formed, the transition section has been formed, and the soft section has been formed); (2) Inner core positioning: The stainless steel segment and the nickel-titanium segment are fixed in the fixture respectively, and the composite parts are overlapped together to prepare for composite; (3) Contact part compounding: The molded structure is assembled together by a fixture, and then the composite part is fixed in the mold cavity for high-temperature heat treatment (temperature is about 1200-1400℃). (4) Winding and fixing the developing wire: fix one end of the platinum core nickel-titanium alloy wire (2) to one end of the soft section at the head end by welding or gluing, and then use an automated winding machine to evenly and tightly wind the gold wire around the soft section at the head end, with the winding length controlled within the range of 20 to 60 mm; (5) TPU coating: the inner core component in step 4 is extruded through an extruder die to coat the inner core component with TPU; (6) Coating: After the guide wire in step 5 is naturally cooled to room temperature, a proximal hydrophobic coating is first coated by ultrasonic spraying technology. After solidification, a hydrophilic coating is coated by dipping or spraying.

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