A guide wire with a vascular stent

Abstract

The present invention discloses a guide wire with a vascular stent, comprising: a guide wire, a vascular stent sleeved on the guide wire, and a connecting wire between the guide wire and the vascular stent; the guide wire includes: an inner guide wire and an outer guide wire; both the inner guide wire and the outer guide wire are tubular structures, the outer guide wire is sleeved on the outside of the inner guide wire, and the vascular stent is located between the inner guide wire and the outer guide wire; the connecting wire is respectively connected to the outer guide wire and the vascular stent, and an easily breakable point is arranged in the middle of the connecting wire; the present invention provides a stable support framework through the double-tube structure of the inner guide wire and the outer guide wire. The inner guide wire serves as the main guide wire, providing hardness and rigidity to ensure the accurate positioning of the guide wire in the blood vessel. The outer guide wire plays a protective role to prevent the vascular stent from directly contacting the blood vessel wall during the positioning process, reducing potential damage to the blood vessel, and can effectively improve the controllability of the guide wire, enabling the doctor to accurately adjust the placement position of the vascular stent, thereby ensuring the stability of the vascular stent and the best deployment effect.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and particularly to a guide wire with a vascular stent. Background Art

[0002] When implanting a vascular stent in a certain area of the carotid artery, this area is above the 6th and 7th cervical vertebrae, usually referring to the higher part of the internal carotid artery near the base of the skull. Implanting a vascular stent in this position is usually for treating or preventing cerebrovascular diseases caused by carotid artery stenosis. Carotid artery stenosis may lead to insufficient blood supply to the brain and increase the risk of stroke. By implanting a vascular stent, the stenosed blood vessel can be dilated to restore normal blood flow, thereby reducing the risk of stroke.

[0003] When implanting a vascular stent in the area above C6-C7 of the carotid artery, special design is required: the carotid artery in this area not only has a complex path, but also has a relatively fast blood flow velocity, which poses extremely high requirements for the operation of the guide wire and catheter. When traditional single-layer guide wires pass through these narrow and curved blood vessels, they are prone to cause damage to the blood vessel wall, and the vascular stent may not be fully deployed or conform to the blood vessel wall after release, thus affecting the treatment effect.

[0004] Therefore, it is necessary to design a guide wire with a vascular stent to solve the above problems. Summary of the Invention

[0005] The present invention overcomes the deficiencies of the prior art and provides a guide wire with a vascular stent.

[0006] To achieve the above object, the technical solution adopted by the present invention is: a guide wire with a vascular stent, comprising: a guide wire, a vascular stent sleeved on the guide wire, and connecting wires between the guide wire and the vascular stent;

[0007] The guide wire includes: an inner guide wire and an outer guide wire; both the inner guide wire and the outer guide wire are tubular structures, the outer guide wire is sleeved outside the inner guide wire, a limiting wire fixed to the inner guide wire is arranged in the cavity between the inner guide wire and the outer guide wire, and the vascular stent is located between the inner guide wire and the outer guide wire;

[0008] The connecting wires are respectively connected to the outer guide wire and the vascular stent, and an easily breakable point is arranged in the middle of the connecting wires.

[0009] In a preferred embodiment of the present invention, the vascular stent is prepared by mixing polycaprolactone and poly(p-dioxanone), the inner diameter of the vascular stent is 3-4 mm, and it fits with the inner wall of the blood vessel through expansion;

[0010] The vascular stent is a multi-layer structure, each layer is composed of a nanofiber membrane, and the fiber structures of adjacent two layers of nanofiber membranes are perpendicular to each other.

[0011] In a preferred embodiment of the present invention, the outer guide wire is made of a nickel-titanium alloy by spiral winding, the inner guide wire is made of a cobalt-chromium alloy by spiral winding, and the thickness of the breakable point is 30%-50% of the wall thickness of the connecting wire, and the connecting wire is made of polycaprolactone.

[0012] In a preferred embodiment of the present invention, the method for preparing the vascular stent includes the following steps:

[0013] S1. Mix polycaprolactone and poly(p-dioxanone) at a mass ratio of 7-10:3-6 and dissolve them in an acidic solution to prepare a mixed solution with a concentration of 10%-15%.

[0014] Step S2. Modify the magnesium-rare earth element alloy nanoparticles, add the modified magnesium-rare earth element alloy nanoparticles to the mixed solution, and mix them evenly to obtain a reinforcement solution.

[0015] Step S3. Prepare several layers of oriented nanofiber membranes by electrospinning the reinforcement solution.

[0016] Step S4. Form a vascular stent by pasting several layers of nanofiber membranes onto a high-speed roller collector layer by layer.

[0017] In a preferred embodiment of the present invention, in step S1, the molecular weight of polycaprolactone is 40,000-100,000, and the molecular weight of poly(p-dioxanone) is 20,000-30,000.

[0018] In a preferred embodiment of the present invention, in step S1, the acidic solution is a trifluoroacetic acid solution with a concentration of 10%-20%.

[0019] In a preferred embodiment of the present invention, in step S2, the particle size of the magnesium-rare earth element alloy nanoparticles is 30nm-80nm, and they are modified by polyacrylic acid.

[0020] In a preferred embodiment of the present invention, in step S2, the mixed solution and the magnesium-rare earth element alloy nanoparticles are mixed at a ratio of 20-25:1-5 and stirred at a temperature of 40-50°C for 10-20 minutes.

[0021] In a preferred embodiment of the present invention, the method for modifying the magnesium-rare earth element alloy nanoparticles by polyacrylic acid includes the following steps:

[0022] Step S21. Wash the magnesium-rare earth element alloy nanoparticles with deionized water and dry the washed nanoparticles.

[0023] Step S22: Dissolve polyacrylic acid with a molecular weight of 500,000 - 1,000,000 in deionized water to obtain a polyacrylic acid solution with a concentration of 0.5% - 5%.

[0024] Step S23: Add the dried magnesium-rare earth element alloy nanoparticles to hydrofluoric acid with a concentration of 10% - 20% for activation treatment, and dry the activated magnesium-rare earth element alloy nanoparticles.

[0025] Step S24: Mix the magnesium-rare earth element alloy nanoparticles and the polyacrylic acid solution at a mass ratio of 1:5 - 10, modify the magnesium-rare earth element alloy nanoparticles, and stir for 30 - 60 minutes.

[0026] Step S25: Take out the modified magnesium-rare earth element alloy nanoparticles, wash them with deionized water, and place the washed magnesium-rare earth element alloy nanoparticles in an oven to dry at 40 - 60 °C for 10 - 15 minutes.

[0027] In a preferred embodiment of the present invention, in the step S4, the inner diameter of the vascular stent is 3 - 4 mm, and the fiber structures in the adjacent two layers of nanofiber membranes in the vascular stent are perpendicular to each other.

[0028] The present invention solves the defects existing in the background technology, and the present invention has the following beneficial effects:

[0029] (1) The present invention provides a guide wire with a vascular stent. By arranging the vascular stent between the inner guide wire and the outer guide wire, the double-tube structure of the inner guide wire and the outer guide wire provides a stable support framework. The inner guide wire serves as the main guide wire, providing hardness and rigidity to ensure the accurate positioning of the guide wire in the blood vessel. The outer guide wire plays a protective role, preventing the vascular stent from directly contacting the blood vessel wall during the positioning process, reducing potential damage to the blood vessel, and effectively improving the controllability of the guide wire, enabling the doctor to precisely adjust the placement position of the vascular stent, thereby ensuring the stability and optimal deployment effect of the vascular stent.

[0030] (2) The present invention prepares the vascular stent by polycaprolactone and poly(p-dioxanone). The vascular stent expands unevenly in the blood vessel wall, causing the vascular stent to self-curl into a tubular structure within the blood vessel wall. Utilizing the telescopic ability of the vascular stent and the reaction force of the blood vessel wall, a mechanical locking effect is generated with the blood vessel wall, increasing the binding force between the vascular stent and the blood vessel wall, enabling the vascular stent to closely fit the blood vessel wall, reducing voids and irregular contacts, increasing the contact area between the vascular stent and the blood vessel wall, having higher mechanical stability, and after self-curling, the multi-layer oriented nanofiber structure forms a more solid tubular structure, which can better resist blood flow impact and mechanical stress of the blood vessel wall, solving the problem that the blood flow velocity near the skull base is relatively fast and the vascular stent will not shift due to changes in blood flow velocity.

[0031] (3) In the preparation of the vascular stent, the present invention adds modified magnesium-rare earth element alloy nanoparticles, enabling good bonding between its surface and the polymer of the nanofiber membrane. By enhancing the adhesion force between layers of the nanofiber membrane, the stability and integrity between layers of the vascular stent during expansion can be ensured, preventing the membrane layers from separating or falling off during use. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0033] Figure 1 is a schematic exploded view of the structure of a guide wire with a vascular stent according to the present invention;

[0034] Figure 2 is a schematic cross-sectional view of the guide wire of the preferred embodiment of the present invention;

[0035] Figure 3 is a schematic three-dimensional view of the guide wire of the preferred embodiment of the present invention;

[0036] In the figure: 1, vascular stent; 2, connecting wire; 3, inner guide wire; 4, outer guide wire; 5, limiting wire; 6, breakable point. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0037] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

[0038] Many specific details are set forth in the following description in order to fully understand the present invention, but the present invention can also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited by the specific embodiments disclosed below.

[0039] In the description of the present application, it should be understood that the orientation or positional relationships indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the protection scope of the present application. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Therefore, the features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more.

[0040] In the description of the present application, it should be noted that unless otherwise clearly specified and defined, the terms "installed", "connected", and "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood through specific circumstances.

[0041] As Figure 1 shown, a guide wire with a vascular stent includes: a guide wire, a vascular stent 1 sleeved on the guide wire, and a connecting wire 2 between the guide wire and the vascular stent 1;

[0042] As Figure 2 and Figure 3 shown, the guide wire includes: an inner guide wire 3 and an outer guide wire 4; both the inner guide wire 3 and the outer guide wire 4 are tubular structures, the outer guide wire 4 is sleeved outside the inner guide wire 3, a limiting wire 5 fixed to the inner guide wire 3 is arranged in the cavity between the inner guide wire 3 and the outer guide wire 4, and the vascular stent 1 is located between the inner guide wire 3 and the outer guide wire 4;

[0043] The connecting wire 2 is respectively connected to the outer guide wire 4 and the vascular stent 1, and an easy break point 6 is arranged in the middle of the connecting wire 2.

[0044] By arranging the vascular stent 1 between the inner guide wire 3 and the outer guide wire 4, the double-tube structure of the inner guide wire 3 and the outer guide wire 4 provides a stable support framework. The inner guide wire 3 serves as the main guide wire, providing hardness and rigidity to ensure the accurate positioning of the guide wire in the blood vessel, and the outer guide wire 4 plays a protective role to prevent the vascular stent 1 from directly contacting the blood vessel wall during the positioning process;

[0045] After the vascular stent 1 is delivered to the vascular position of the designated stenosis area through a guide wire, by applying pressure to the outer guide wire 4 to stretch the outer guide wire 4, the connecting wire 2 is disconnected from the easy break point 6 position, the vascular stent 1 is exposed, the vascular stent 1 expands until it fits tightly with the inner wall of the blood vessel, and then the inner guide wire 3 and the outer guide wire 4 are withdrawn. Thus, the vascular stent 1 supports the blood vessel in the stenosis area, dilates the stenotic blood vessel, restores normal blood flow, and thereby reduces the risk of stroke.

[0046] It should be noted that through the setting of the connecting wire 2, the vascular stent 1 can enter the blood vessel synchronously with the guide wire. In order to enable separation between the outer guide wire 4 and the vascular stent 1, an easy break point 6 is set at the middle position of the connecting wire 2. The thickness of the easy break point 6 is 30%-50% of the wall thickness of the connecting wire 2. When the vascular stent 1 is pushed to the target blood vessel by the guide wire, through the fracture of the easy break point 6, excessive force acting on the inner wall of the blood vessel can be effectively avoided, preventing blood vessel damage caused by excessive operation of the guide wire. The setting of the easy break point 6 can ensure that the vascular stent 1 is accurately deployed at the appropriate moment and will not cause improper position of the vascular stent 1 or blood vessel damage due to continuous application of force by the guide wire, thereby accelerating the operation process, reducing the operation time, and improving the safety of the operation.

[0047] A limiting wire 5 fixed to the inner guide wire 3 is set between the inner guide wire 3 and the outer guide wire 4. During the process of stretching the outer guide wire 4 to separate it from the vascular stent 1, the limiting wire 5 plays a role in supporting and limiting the vascular stent 1, preventing the vascular stent 1 from moving synchronously with the outer guide wire 4, so as to separate the vascular stent 1 from the outer guide wire 4 and expose it in the blood vessel in the stenosis area.

[0048] In the present invention, the vascular stent 1 is prepared by mixing polycaprolactone and poly(p-dioxanone). The inner diameter of the vascular stent 1 is 3-4 mm, and it fits with the inner wall of the blood vessel through expansion.

[0049] Poly(p-dioxanone) is a polymer with biodegradable properties and relatively strong hydrophilicity. In an aqueous solution, especially under physiological conditions, the molecular chain of poly(p-dioxanone) can absorb water and expand. When exposed to body fluids or blood, it can expand, enabling the vascular stent 1 to gradually unfold in the blood vessel and come into close contact with the blood vessel wall, helping the vascular stent 1 to better fit with the blood vessel wall.

[0050] As a synthetic polymer with a relatively long degradation period, polycaprolactone has excellent mechanical strength and stability. The glass transition temperature of polycaprolactone is relatively high at 60 °C and remains relatively stable at 37 °C. Therefore, it can provide the rigidity and structural support required by the vascular stent 1 to prevent excessive expansion.

[0051] When the vascular stent 1 is exposed to blood in a blood vessel, the expansibility of poly(p-dioxanone) will cause the surface of the vascular stent 1 to expand, resulting in the gradual stretching and deformation of the vascular stent 1 material. Due to the relatively stable structure of polycaprolactone, the expansion difference of the vascular stent 1 causes the vascular stent 1 to form a self-curling structure in the blood vessel, enabling the vascular stent 1 to closely fit the blood vessel wall, reducing voids and irregular contacts, increasing the contact area between the vascular stent 1 and the blood vessel wall, having higher mechanical stability, and after the multi-layer oriented nanofiber structure self-curls, it forms a more robust tubular structure that can better resist blood flow impact and the mechanical stress of the blood vessel wall, solving the problem that the blood flow velocity near the base of the skull is relatively fast and the stent will not shift due to changes in blood flow velocity.

[0052] It should be noted that the stability and elasticity of the vascular stent 1 enable the blood vessel to maintain flexibility and elasticity while being supported, thus ensuring that the vascular stent 1 can maintain good contact with the blood vessel wall for a long time.

[0053] The vascular stent 1 is a multi-layer structure, and each layer is composed of a nanofiber membrane. The fiber structures of the nanofiber membranes in adjacent layers are perpendicular to each other;

[0054] By having the fiber structures of adjacent layers perpendicular to each other, the fibers in each layer will provide support in different directions, mimicking the multi-layer structure of natural blood vessels, making the vascular stent 1 stronger and more stable, capable of withstanding greater external force impacts or pressures without being easily deformed or collapsed;

[0055] The different orientations of the fiber structure can increase the tensile and compressive resistance of the vascular stent 1. For example, vertically oriented fibers can enhance the longitudinal strength of the vascular stent 1, while horizontally oriented fibers contribute to enhancing its lateral stability, so that the bearing capacity of the vascular stent 1 in the blood vessel is balanced, improving the overall stability.

[0056] In the present invention, the outer guide wire 4 is made by helically winding nickel-titanium alloy, and has a front soft transition section, a middle rigid support section, and a rear operation handle; the length of the front soft transition section is 20 - 30 millimeters, which is used to reduce damage to the blood vessel wall; the middle rigid support section is used to provide the stability of the guide wire; the rear operation handle facilitates the user's precise control of the guide wire; the inner guide wire 3 is made by helically winding cobalt-chromium alloy, and the connecting wire 2 is made of polycaprolactone.

[0057] In the present invention, the preparation method of the vascular stent 1 includes the following steps:

[0058] Step S1: Mix polycaprolactone and poly(p-dioxanone) at a mass ratio of 7 - 10:3 - 6 and dissolve them in an acidic solution to prepare a mixed solution with a concentration of 10 - 15%;

[0059] Step S2: Modify the magnesium-rare earth element alloy nanoparticles, add the modified magnesium-rare earth element alloy nanoparticles into the mixed solution, and mix them evenly to obtain a reinforcing solution;

[0060] Step S3: Prepare an oriented nanofiber membrane with several layers by electrospinning the reinforcing solution;

[0061] Step S4: Paste several layers of nanofiber membranes onto a high-speed roller collector layer by layer to form a vascular stent 1.

[0062] In step S1, the molecular weight of polycaprolactone is 40,000 - 100,000, and the molecular weight of poly(p-dioxanone) is 20,000 - 30,000.

[0063] The acidic solution is a trifluoroacetic acid solution with a concentration of 10% - 20%. Mixing polycaprolactone and poly(p-dioxanone) and adding them to the trifluoroacetic acid solution can effectively dissolve polycaprolactone and poly(p-dioxanone). At the same time, it has a strong depolarizing effect, which can promote the dissolution process. In addition, the trifluoroacetic acid solvent has a good regulating effect on the solubility of the polymer and the performance of electrospinning, enabling the viscosity of the solution to be moderate and suitable for subsequent electrospinning operations;

[0064] Dissolving polycaprolactone and poly(p-dioxanone) in the acidic solution provides a basis for subsequent spinning, ensuring that the nanofiber structure formed during the electrospinning process is uniform and the fiber surface is smooth.

[0065] In the present invention, in step S2, the particle size of the magnesium-rare earth element alloy nanoparticles is 30 nm - 80 nm, and they are modified by polyacrylic acid.

[0066] In step S2, the mixed solution and the magnesium-rare earth element alloy nanoparticles are mixed at a ratio of 20 - 25:1 - 5, and stirred at a temperature of 40 - 50 °C for 10 - 20 min.

[0067] In the present invention, the method for modifying the magnesium-rare earth element alloy nanoparticles by polyacrylic acid includes the following steps:

[0068] Step S21: Wash the magnesium-rare earth element alloy nanoparticles with deionized water to remove possible impurities, contaminants, and oxides on the particle surface, so as to ensure its surface cleanliness and better reaction with polyacrylic acid. The washed magnesium-rare earth element alloy nanoparticles need to be dried to remove moisture to ensure the effectiveness during the modification process;

[0069] Step S22: Dissolve polyacrylic acid with a molecular weight of 500,000 - 1,000,000 in deionized water to obtain a polyacrylic acid solution with a concentration of 0.5% - 5%;

[0070] Step S23: Add the dried magnesium-rare earth element alloy nanoparticles into hydrofluoric acid with a concentration of 10%-20% for activation treatment to remove the oxide layer on the surface of the magnesium-rare earth element alloy nanoparticles and effectively expose the metal surface, thereby improving the efficiency of subsequent modification reactions. Dry the activated magnesium-rare earth element alloy nanoparticles to remove the residual hydrofluoric acid and prepare for modification;

[0071] Step S24: Mix the magnesium-rare earth element alloy nanoparticles and the polyacrylic acid solution in a mass ratio of 1:5-10 to modify the magnesium-rare earth element alloy nanoparticles and stir for 30-60 min;

[0072] Through the modification of polyacrylic acid, a strong hydrophilic layer can be formed on the surface of the magnesium-rare earth element alloy nanoparticles, thereby improving the compatibility and adhesion of the magnesium-rare earth element alloy nanoparticles with the mixed solution of the polymer matrix polycaprolactone and poly(p-dioxanone). Moreover, polyacrylic acid not only improves the dispersibility of the particles but also enhances the binding force between the particles and polycaprolactone and poly(p-dioxanone) in the solution, promoting the stability of the reinforcing solution and the properties of the fibers during the subsequent electrospinning process;

[0073] Step S25: Take out the modified magnesium-rare earth element alloy nanoparticles and wash them with deionized water. Place the washed magnesium-rare earth element alloy nanoparticles in an oven and dry them at 40-60 °C for 10-15 min.

[0074] In Step S3 and Step S4, load the obtained reinforcing solution into a syringe. The syringe needs to be connected to the nozzle of an electrospinning device (ET-3556H electrospinning machine, sourced from Beijing Yongkang Leye Technology Development Co., Ltd.) with a diameter of 50-100 nm. The solution in the syringe is controlled by a pump to ensure a stable flow rate and solution supply. Apply a high voltage of 10 kV-30 kV between the syringe and the collector to generate a strong electric field. The polymer in the solution will be stretched under the action of the electric field to form slender fibers. At the other end of the electrospinning, collect the fibers through the collector. The fibers will be stretched and deposited on its surface to form a nanofiber membrane. Change the movement trajectory of the collector, so that the arrangement of each layer of nanofiber membrane prepared is different, making the fiber structures in the adjacent two layers of nanofiber membranes in the subsequent prepared vascular stent 1 perpendicular to each other;

[0075] The inner diameter of the vascular stent 1 is 3-4 mm. The fiber structures in the adjacent two layers of nanofiber membranes in the vascular stent 1 are perpendicular to each other. By the perpendicularity of the fiber structures in the adjacent layers, each layer of fibers can provide support in different directions, mimicking the multi-layer structure of natural blood vessels, making the vascular stent 1 stronger and more stable and capable of withstanding greater external force impacts or pressures without being easily deformed or collapsed.

[0076] In summary, in order to verify that different ratios of polycaprolactone and polydioxanone directly affect the expansibility, structural stability, and the fitting effect with the blood vessel wall of the vascular stent 1, the following experiments were conducted.

[0077] Experimental Example 1:

[0078] I. Experimental Purpose

[0079] To study the expansibility, stability, and fitting effect of vascular stents with different ratios of polycaprolactone (PCL) and polydioxanone (PCDC) on the blood vessel wall;

[0080] To optimize the material ratio by quantitatively analyzing the expansibility, contact uniformity, pressure distribution, and fitting with the blood vessel wall of the vascular stent.

[0081] II. Experimental Procedures

[0082] (I) Preparation of Vascular Stent Samples

[0083] Example 1: Select polycaprolactone with a molecular weight of 50,000 (from Shenzhen Guanghua Weiye Co., Ltd.), and polydioxanone with a molecular weight of 30,000 (from Wuhan Xinxin Jiali Biotechnology Co., Ltd.). Mix polycaprolactone and polydioxanone in a mass ratio of 7:3 and dissolve them in a 15% trifluoroacetic acid solution to obtain a mixed solution. Load the solution into a syringe. The syringe needs to be connected to a nozzle of 50 nm of an electrospinning device. The solution in the syringe is controlled by a pump. Apply a high voltage of 10 kV between the syringe and the collector, control the flow rate of the spinning solution at 0.45 ml / h to form slender fibers. At the other end of the electrospinning, collect the fibers through the collector. The fibers will be stretched and deposited on its surface to form a nanofiber membrane. Change the movement trajectory of the collector so that the arrangement of each layer of nanofiber membrane prepared is different, making the fiber structures of adjacent nanofiber membranes prepared perpendicular to each other. Through the perpendicularity of the fiber structures of adjacent layers, a vascular stent with a diameter of 3 mm and a length of 10 mm is formed.

[0084] Example 2: Polycaprolactone with a molecular weight of 50,000 and poly(p-dioxanone) with a molecular weight of 30,000 were selected. Polycaprolactone and poly(p-dioxanone) were mixed at a mass ratio of 7:4 and dissolved in a 15% trifluoroacetic acid solution to obtain a mixed solution. The solution was loaded into a syringe. The syringe needed to be connected to a nozzle of the electrospinning device with a diameter of 50 nm. The solution in the syringe was controlled by a pump. A high voltage of 10 kV was applied between the syringe and the collector. The flow rate of the spinning solution was controlled at 0.45 ml / h to form slender fibers. At the other end of the electrospinning, the fibers were collected by the collector. The fibers would be stretched and deposited on its surface to form a nanofiber membrane. The movement trajectory of the collector was changed, so that the arrangement of each layer of nanofiber membrane prepared was different, making the fiber structures of adjacent nanofiber membranes prepared subsequently perpendicular to each other. Through the perpendicularity of the fiber structures of adjacent layers, a vascular stent with a diameter of 3 mm and a length of 10 mm was formed.

[0085] Example 3: Polycaprolactone with a molecular weight of 50,000 and poly(p-dioxanone) with a molecular weight of 30,000 were selected. Polycaprolactone and poly(p-dioxanone) were mixed at a mass ratio of 7:5 and dissolved in a 15% trifluoroacetic acid solution to obtain a mixed solution. The solution was loaded into a syringe. The syringe needed to be connected to a nozzle of the electrospinning device with a diameter of 50 nm. The solution in the syringe was controlled by a pump. A high voltage of 10 kV was applied between the syringe and the collector. The flow rate of the spinning solution was controlled at 0.45 ml / h to form slender fibers. At the other end of the electrospinning, the fibers were collected by the collector. The fibers would be stretched and deposited on its surface to form a nanofiber membrane. The movement trajectory of the collector was changed, so that the arrangement of each layer of nanofiber membrane prepared was different, making the fiber structures of adjacent nanofiber membranes prepared subsequently perpendicular to each other. Through the perpendicularity of the fiber structures of adjacent layers, a vascular stent with a diameter of 3 mm and a length of 10 mm was formed.

[0086] Example 4: Polycaprolactone with a molecular weight of 50,000 and poly(p-dioxanone) with a molecular weight of 30,000 were selected. Polycaprolactone and poly(p-dioxanone) were mixed at a mass ratio of 7:6 and dissolved in a 15% trifluoroacetic acid solution to obtain a mixed solution. The solution was loaded into a syringe. The syringe needed to be connected to a nozzle of the electrospinning device with a diameter of 50 nm. The solution in the syringe was controlled by a pump. A high voltage of 10 kV was applied between the syringe and the collector. The flow rate of the spinning solution was controlled at 0.45 ml / h to form slender fibers. At the other end of the electrospinning, the fibers were collected by the collector. The fibers would be stretched and deposited on its surface to form a nanofiber membrane. The movement trajectory of the collector was changed, so that the arrangement of each layer of nanofiber membrane prepared was different, making the fiber structures of adjacent nanofiber membranes prepared subsequently perpendicular to each other. Through the perpendicularity of the fiber structures of adjacent layers, a vascular stent with a diameter of 3 mm and a length of 10 mm was formed.

[0087] (2) Experiments on the vascular stent samples

[0088] 1. An artificial blood vessel model was fabricated using 3D printing technology to simulate a blood vessel with a diameter of 6 mm. The vascular stents prepared in Examples 1 to 4 were respectively inserted into the artificial blood vessel model and placed in physiological saline at 37°C. The expansion of the vascular stents in the simulated blood vessel was observed and recorded. By recording the change in the expansion diameter of the vascular stents after 24 hours, the expansion rate was calculated. The expansion rate = (expansion after - expansion before) / expansion before × 100%; 100%;

[0089] 2. The contact between the vascular stent and the blood vessel wall was observed by CT scanning technology, and the contact area, contact uniformity, and contact pressure were measured;

[0090] Contact area: Record the contact area between the vascular stent and the blood vessel wall to evaluate whether the vascular stent fits the entire inner wall of the blood vessel;

[0091] Contact uniformity: Evaluate whether the contact between the surface of the vascular stent and the blood vessel wall is uniform and whether there are voids with non-uniform contact. Calculate the contact area between the vascular stent and the blood vessel wall. If the contact area ≥ 90%, it is excellent; if 90% > contact area ≥ 70%, it is good; if 70% > contact area ≥ 50%, it is average; if the contact area < 50%, it is poor;

[0092] Contact pressure: Use a pressure sensor or strain gauge to measure the pressure distribution when the vascular stent contacts the blood vessel wall to ensure uniform pressure distribution to reduce damage to the blood vessel;

[0093] 3. Simulate the dynamic environment in the blood vessel such as blood flow and blood pressure fluctuations, and use a TABER friction and wear tester to measure the friction force between the vascular stent and the simulated blood vessel wall. The specific steps are as follows:

[0094] Place the vascular stent and the simulated blood vessel wall in the TABER friction and wear tester, and apply a certain pressure to simulate the pressure inside the blood vessel wall at 120 mmHg. A relative movement speed of 5 mm / s is used to simulate the blood flow speed, and the friction force between the vascular stent and the blood vessel wall is measured. The friction forces of the vascular stents obtained in Examples 1 to 4 are tested under the same pressure and movement conditions;

[0095] Observe the long-term stability of the vascular stent in the blood vessel and record whether the vascular stent can maintain its original shape and whether there is over-expansion or collapse;

[0096] The following data were obtained, as shown in Table 1

[0097] Table 1

[0098]

[0099] By comparing the data of Examples 1 to 4, it can be concluded that when the proportion of polydioxanone increases, the water absorption and expansion of polydioxanone, when the vascular stent contacts the vascular wall, the water and small molecules of the fluid components in the vascular wall can penetrate into the fibers of the vascular stent, resulting in increased chain fluidity, so that the vascular stent expands in the vascular wall until it contacts the vascular wall, while polycaprolactone is structurally stable at 37°C, and the vascular stent forms irregular expansion and is self-curling, and the contact area between the vascular stent and the blood vessel increases, and can fit closely to the vascular wall. The higher the expansion capacity of the vascular stent in the blood vessel, the larger the contact area between the vascular stent and the inner wall of the blood vessel, and the closer it fits to the inner wall of the blood vessel, the greater the friction and adhesion between the vascular wall and the stent, which helps the stent to maintain a stable state in the blood vessel for a longer time, and prevents the stent from shifting or falling off;

[0100] However, as the proportion of polydioxanone is too large, the vascular stent expands irregularly and becomes self-curling, and the contact area between the vascular stent and the blood vessel increases accordingly. The flexibility and low stiffness of polydioxanone make the stent surface smoother. When this smooth surface contacts the blood vessel wall, the friction and adhesion are low. In addition, due to the high flexibility of polydioxanone, the vascular stent may cause a slight slip between the inner wall of the blood vessel and the stent when expanding. The slip will reduce the contact surface, thereby reducing the friction and adhesion.

[0101] At the same time, the flexibility of polydioxanone makes it impossible to evenly distribute the force due to the uneven pressure distribution on the blood vessel wall in dynamic environments such as blood flow fluctuations, vascular contraction and expansion. Deformation within the blood vessel may cause pressure concentration or uneven distribution, affecting the contact stability between the stent and the blood vessel wall.

[0102] Experimental Example 2:

[0103] 1. Purpose of the experiment

[0104] The enhancing effect of different concentrations of magnesium-rare earth alloy nanoparticles on the adhesion between nanofiber membrane layers was compared.

[0105] 2. Experimental steps

[0106] 1. Preparation steps

[0107] Example 5: Select polycaprolactone with a molecular weight of 50,000 (from Shenzhen Guanghua Weiye Co., Ltd.) and polydioxanone with a molecular weight of 30,000 (from Wuhan Xinxin Jiali Biotechnology Co., Ltd.), mix polycaprolactone and polydioxanone in a mass ratio of 7:5, and dissolve them in a trifluoroacetic acid solution with a concentration of 15% to obtain a mixed solution;

[0108] Polyacrylic acid with a molecular weight of 800,000 (from Shanghai Yuanye Bio-Technology Co., Ltd.) was dissolved in deionized water to obtain a polyacrylic acid solution with a concentration of 1.5%. The dried magnesium-rare earth element alloy nanoparticles were added to 10% hydrofluoric acid for activation treatment. The activated magnesium-rare earth element alloy nanoparticles were mixed with the polyacrylic acid solution at a mass ratio of 1:8 to modify the magnesium-rare earth element alloy nanoparticles, and stirred for 45 minutes. The modified magnesium-rare earth element alloy nanoparticles were taken out and washed with deionized water. The washed magnesium-rare earth element alloy nanoparticles were placed in an oven and dried at 40 °C for 15 minutes;

[0109] The dried magnesium-rare earth element alloy nanoparticles and the mixed solution were mixed at a ratio of 1:20, and stirred at 40 °C for 20 minutes to obtain a reinforcement solution. The solution was loaded into a syringe, and the syringe needed to be connected to a nozzle of 50 nm of an electrospinning device. The solution in the syringe was controlled by a pump. A high voltage of 10 kV was applied between the syringe and the collector. The flow rate of the electrospinning solution was controlled at 0.45 ml / h to form slender fibers. At the other end of the electrospinning, the fibers were collected by the collector, and the fibers would be stretched and deposited on its surface to form a nanofiber membrane. The movement trajectory of the collector was changed, so that the arrangement of each layer of nanofiber membrane prepared was different, and the fiber structures of adjacent nanofiber membranes prepared subsequently were perpendicular to each other. Through the perpendicularity of the fiber structures of adjacent layers, a vascular stent with a diameter of 3 mm and a length of 10 mm was formed, and the vascular stent was sheared and flattened to obtain a vascular stent with a layered structure.

[0110] Example Six: It is substantially the same as Example Five, except that the dried magnesium-rare earth element alloy nanoparticles and the mixed solution were mixed at a ratio of 2:20, and a vascular stent with a diameter of 3 mm and a length of 10 mm was prepared by an electrospinning device, and the vascular stent was sheared and flattened to obtain a vascular stent with a layered structure.

[0111] Example Seven: It is substantially the same as Example Five, except that the dried magnesium-rare earth element alloy nanoparticles and the mixed solution were mixed at a ratio of 3:20, and a vascular stent with a diameter of 3 mm and a length of 10 mm was prepared by an electrospinning device, and the vascular stent was sheared and flattened to obtain a vascular stent with a layered structure.

[0112] Example Eight: It is substantially the same as Example Five, except that the dried magnesium-rare earth element alloy nanoparticles and the mixed solution were mixed at a ratio of 4:20, and a vascular stent with a diameter of 3 mm and a length of 10 mm was prepared by an electrospinning device, and the vascular stent was sheared and flattened to obtain a vascular stent with a layered structure.

[0113] Example 9: It is substantially the same as Example 5, except that the dried magnesium-rare earth element alloy nanoparticles and the mixed solution are mixed in a ratio of 5:20, and a vascular stent with a diameter of 3 mm and a length of 10 mm is prepared by an electrospinning device, and the vascular stent is sheared and flattened to obtain a vascular stent with a layered structure.

[0114] (2) Experiments on vascular stent samples

[0115] 1. Shearing force test: Use a universal shearing force tester to place the vascular stent with a layered structure in the test fixture, gradually apply a shearing force until separation occurs between the film layers, record the maximum shearing force value, and measure the adhesion force between each film layer and the film layer.

[0116] 2. Tensile force test: Use a tensile tester to measure the tensile adhesion force between the film layers of the vascular stent with a layered structure. By stretching each layer of the film until film layer separation occurs, record the tensile strength; measure the tensile forces of different film layer combinations.

[0117] Shear and flatten the vascular stent obtained in Example 3 to obtain a vascular stent with a layered structure. Conduct shear and tensile tests on the vascular stents with a layered structure obtained in Example 3, Example 5 to Example 9 respectively, as shown in Table 2;

[0118] Table 2

[0119]

[0120] By comparing the vascular stents with a layered structure obtained in Example 3, Example 5 to Example 9, for the vascular stent with a layered structure obtained in Example 3, the shearing force and tensile force between its layers are relatively low. However, with the addition of magnesium-rare earth element alloy nanoparticles, the shearing force and tensile force between the layers of the vascular stent with a layered structure increase. The main reason is that after the surface of the magnesium-rare earth element alloy nanoparticles is modified with polyacrylic acid, it has chemical groups of carboxyl and amino. These chemical groups can form hydrogen bonds with the hydroxyl and amino groups of polycaprolactone and poly(p-dioxanone). This weak intermolecular interaction can stabilize the binding between the film layers;

[0121] Moreover, due to the large specific surface area and high surface energy of the magnesium-rare earth element alloy nanoparticles, they act as an "adhesive" between multiple film layers. When the magnesium-rare earth element alloy nanoparticles are evenly distributed in the nanofiber membrane, the surface of the magnesium-rare earth element alloy nanoparticles will come into contact with the film layers, thereby enhancing the adhesion force between the layers. Specifically, the magnesium-rare earth element alloy nanoparticles have high mechanical strength, embed between different film layers and form physical bonds, making the contact between the film layers closer. And the magnesium-rare earth element alloy nanoparticles exist as a "bridge", connecting the fiber structures of different layers, playing the role of bonding and stabilizing the film layers. Through this "bridging" mechanism, the bonding force between different film layers is enhanced, thus ensuring the stability and integrity between the layers during the expansion of the vascular stent and preventing the film layers from separating or falling off during use.

[0122] However, when the content of the magnesium-rare earth element alloy nanoparticles is too large, the shear force and tensile force between the layers of the vascular stent will decrease because there are interaction forces between polycaprolactone, poly(p-dioxanone) and the magnesium-rare earth alloy nanoparticles. When the content of the magnesium-rare earth alloy nanoparticles is too high, the interaction forces between polycaprolactone, poly(p-dioxanone) and the magnesium-rare earth alloy nanoparticles may compete, resulting in the weakening of the interaction forces of the particles at the interface and affecting the adhesion force between the film layers. The large amount of magnesium-rare earth alloy nanoparticles increases the space occupation at the interface, thus weakening the bonding force between the particles and the matrix. In summary, Example Eight is the optimal solution of the present invention.

[0123] Based on the ideal embodiments of the present invention as an inspiration, through the above description, relevant personnel can make various changes and modifications completely within the scope without departing from the technical idea of this invention. The technical scope of this invention is not limited to the content in the specification, and the technical scope must be determined according to the scope of the claims.

Claims

1. A guide wire with a vascular stent, comprising: A guide wire, and a vascular stent mounted on the guide wire, wherein a connecting wire is provided between the guide wire and the vascular stent; characterized in that: The guide wire comprises: an inner guide wire and an outer guide wire; both the inner guide wire and the outer guide wire are tubular structures, the outer guide wire is sleeved on the outside of the inner guide wire, a limiting wire fixed to the inner guide wire is provided in the cavity between the inner guide wire and the outer guide wire, and the vascular stent is located between the inner guide wire and the outer guide wire; The connecting wire is connected to the outer guide wire and the vascular stent respectively, and a breakable point is arranged in the middle of the connecting wire; The outer guide wire is made of a nickel-titanium alloy by spiral rolling, the inner guide wire is made of a cobalt-chromium alloy by spiral rolling, and the thickness of the easy-to-break point is 30%-50% of the wall thickness of the connecting wire. The connecting wire is made of polycaprolactone.

2. A guidewire with a vascular stent according to claim 1, characterized in that: The vascular stent is prepared by mixing polycaprolactone and polydioxanone, the inner diameter of the vascular stent is 3-4 mm, and the vascular stent is adhered to the inner wall of the blood vessel by expansion; The vascular stent is a multi-layer structure, each layer is composed of nanofiber membranes, and the fiber structures of the nanofiber membranes of two adjacent layers are perpendicular to each other.

3. A guide wire with a vascular stent according to claim 1, characterized in that: The method for preparing the vascular stent comprises the following steps: Step S1, mixing polycaprolactone and polydioxanone in a mass ratio of 7-10:3-6, and dissolving them in an acidic solution to prepare a mixed solution with a concentration of 10-15%; Step S2, modifying the magnesium-rare earth alloy nanoparticles, adding the modified magnesium-rare earth alloy nanoparticles into the mixed solution, and mixing them evenly to obtain a reinforcement solution; Step S3, preparing a plurality of oriented nanofiber membrane layers by electrospinning the reinforcement solution; Step S4, forming a vascular stent by pasting several layers of nanofiber membranes on a high-speed drum collector.

4. A guide wire with a vascular stent according to claim 3, characterized in that: In the step S1, the molecular weight of polycaprolactone is 40,000-100,000, and the molecular weight of polydioxanone is 20,000-30,000.

5. The guide wire with a vascular stent according to claim 3, characterized in that: In step S1, the acidic solution is a trifluoroacetic acid solution with a concentration of 10%-20%.

6. The guide wire with a vascular stent according to claim 3, characterized in that: In the step S2, the particle size of the magnesium-rare earth alloy nanoparticles is 30nm-80nm, and the nanoparticles are modified by polyacrylic acid.

7. The guide wire with a vascular stent according to claim 3, characterized in that: In the step S2, the mixed solution and the magnesium-rare earth alloy nanoparticles are mixed in a ratio of 20-25:1-5, and stirred at a temperature of 40-50° C. for 10-20 minutes.

8. The guide wire with a vascular stent according to claim 3, characterized in that: The method for modifying magnesium-rare earth alloy nanoparticles by polyacrylic acid comprises the following steps: Step S21, washing the magnesium-rare earth alloy nanoparticles with deionized water, and drying the washed nanoparticles; Step S22, dissolving polyacrylic acid with a molecular weight of 500000-1000000 in deionized water to obtain a polyacrylic acid solution with a concentration of 0.5%-5%; Step S23, adding the dried magnesium-rare earth alloy nanoparticles to hydrofluoric acid with a concentration of 10%-20% for activation treatment, and drying the activated magnesium-rare earth alloy nanoparticles; Step S24, mixing the magnesium-rare earth alloy nanoparticles and the polyacrylic acid solution at a mass ratio of 1:5-10 to modify the magnesium-rare earth alloy nanoparticles, and stirring for 30-60 minutes; Step S25, taking out the modified magnesium-rare earth alloy nanoparticles and washing them with deionized water, and placing the washed magnesium-rare earth alloy nanoparticles in an oven at 40-60° C. to dry for 10-15 minutes.

9. The guide wire with a vascular stent according to claim 3, characterized in that: In step S4, the inner diameter of the vascular stent is 3-4 mm, and the fiber structures in two adjacent layers of the nanofiber membranes in the vascular stent are perpendicular to each other.

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