Vascular stent, vascular stent system, and method for preparing same

Abstract

The present invention relates to the field of medical device technology, and in particular, to a vascular stent, a vascular stent system, and a method for preparing same. The method comprises: dissolving a degradable water-insoluble polymer in a solvent to prepare a first spinning solution, dissolving a degradable water-soluble polymer in a solvent to prepare a second spinning solution, connecting the first spinning solution and the second spinning solution to an electrospinning device, and performing electrostatic spinning to form a vascular stent. In the described preparation process, the degradable water-insoluble polymer and the degradable water-soluble polymer are subjected to a spinning process for vascular stent processing. When the vascular stent is delivered and expanded in vivo, a degradable water-soluble polymer part of the fiber filament is dissolved in the body fluid, thereby enhancing the slippage capability between fibers and improving the expansion and over-expansion performance of the stent.

Description

Vascular stent, vascular stent system and preparation method Technical Field

[0001] The present invention relates to the technical field of medical devices, and in particular to a vascular stent, a vascular stent system and a preparation method thereof. Background Art

[0002] Biodegradable vascular stents are currently widely used in the treatment of vascular diseases. Vascular stents are not only used to treat coronary artery stenosis, but all blood vessels in the human body, including the aorta, abdominal aorta, intracranial blood vessels, peripheral blood vessels, etc., can be treated with vascular stents after lesions occur.

[0003] Taking coronary artery treatment as an example, biodegradable vascular stents are considered to be revolutionary products for coronary artery treatment. Currently, most degradable stents use laser engraving or multi-axis 3D printing technology to cut or print wave rods and connecting rod structures on the surface of degradable polymers or degradable metal tubes to provide short-term support performance, which will eventually be completely degraded in the body.

[0004] Electrospinning is a molding method in which a high-voltage electrostatic field is applied to a polymer, and the charged droplets are stretched to form a jet under the action of the electric field force. At the same time, the solvent evaporates and solidifies into a micro-nano fiber aggregate. Electrospun vascular stents (hereinafter referred to as vascular stents) are three-dimensional micro-nanoscale fiber aggregate scaffolds similar to extracellular matrix. Compared with macroscopic large-pore stents, the uniform three-dimensional grid structure of vascular stents has lower shear stress and does not cause local turbulence. In addition, by changing the relevant process parameters of vascular stents to adjust the fiber diameter, pore size and porosity, cell adhesion and growth can be induced, tissue regeneration can be promoted, and vascular function can be restored.

[0005] During interventional surgery, the stent will be compressed to a smaller diameter outside the body. After being delivered to the diseased area, a pressure device is used to expand the balloon, causing the stent to expand and adhere tightly to the diseased area, and finally the balloon is withdrawn.

[0006] Unlike the wave-rod structure of traditional stents, vascular stents utilize a three-dimensional interwoven structure of micro-nano fibers. During circumferential compression and expansion, the fibers within the stent have poor deformation capacity along the direction of force applied, making it difficult for them to slide and align with each other. Consequently, many fibers break under tension, resulting in significant loss of mechanical properties. Furthermore, excessive fiber tension during expansion causes a sharp decline in mechanical properties, resulting in poor over-expansion capabilities and, in severe cases, possible fracture.

[0007] Therefore, a vascular stent, a vascular stent system and a preparation method are needed to improve the phenomenon that the three-dimensional fiber structure of the vascular stent has poor support performance and mechanical properties after compression, gripping and expansion. Summary of the Invention

[0008] The present invention provides a vascular stent, a vascular stent system and a preparation method thereof, so as to improve the phenomenon that the three-dimensional fiber structure of the vascular stent has poor supporting performance and mechanical properties after compression, gripping and expansion.

[0009] The present invention provides a method for preparing a vascular stent, comprising:

[0010] Dissolving a degradable water-insoluble polymer in a solvent to form a first spinning solution, dissolving a degradable water-soluble polymer in a solvent to form a second spinning solution,

[0011] The first spinning solution and the second spinning solution are introduced into an electrospinning device to perform electrostatic spinning to form a vascular stent.

[0012] Optionally, the first spinning solution and the second spinning solution are simultaneously introduced into the electrospinning device to perform an electrostatic spinning process to generate coaxial fiber filaments, and the coaxial fiber filaments are interwoven to form at least a portion of the vascular stent.

[0013] The coaxial fiber filament includes a core layer and a shell layer, wherein the shell layer is wrapped around the core layer, the core layer is generated by the first spinning solution, and the shell layer is generated by the second spinning solution.

[0014] Optionally, the first spinning solution is separately introduced into the electrospinning device to perform an electrostatic spinning process to generate solid fiber filaments, and the solid fiber filaments are interwoven to form at least a portion of the vascular stent.

[0015] Optionally, the coaxial fiber filaments are interwoven to form a first fiber layer, the solid fiber filaments are interwoven to form a second fiber layer, and the first fiber layer and the second fiber layer are stacked to form the vascular stent.

[0016] Optionally, the thickness of the first fiber layer accounts for 60%-80% of the total thickness of the vascular stent.

[0017] Optionally, the degradable water-insoluble polymer includes one or a mixture and / or copolymer of two or more of polylactide, polyglycolide, polycaprolactone, polydioxanone, polytrimethylene carbonate, polyesteramide, polyhydroxyalkanoate, polyurethane and polyglycolide.

[0018] Optionally, the degradable water-soluble polymer includes polyvinyl alcohol, polyethylene glycol, polyethylene oxide, polyvinyl pyrrolidone, polyethylene imine, hyaluronic acid, gelatin, collagen, sodium alginate and a mixture and / or copolymer of one or more of hyaluronic acid.

[0019] Optionally, the solvent includes at least one of water, hexafluoroisopropanol, dichloromethane, chloroform, tetrahydrofuran, N,N-dimethylformamide, dimethyl sulfoxide, acetone, n-propyl acetate and n-butyl acetate.

[0020] Optionally, the vascular stent preparation method further comprises:

[0021] heat-treating the prepared vascular stent;

[0022] The heat treatment comprises:

[0023] The vascular stent is placed in a heat treatment medium, and the heat treatment medium is heated, kept heated, and cooled.

[0024] Optionally, the heat treatment medium includes one of air, ethanol, ethylene glycol, glycerol, or a mixture of two or more thereof.

[0025] The present invention also provides a method for preparing a vascular stent system, comprising:

[0026] A vascular stent prepared by the above-mentioned vascular stent preparation method;

[0027] Selecting a balloon and sheathing the vascular stent outside the balloon;

[0028] The vascular stent is placed in a compression medium for compression, so as to compress the vascular stent onto the balloon.

[0029] Optionally, the pressing medium includes one or a mixture of two or more of air, ethanol, ethylene glycol, and glycerol.

[0030] The present invention further provides a blood vessel stent, comprising a stent body, wherein the stent body comprises a first fiber layer and a second fiber layer stacked together;

[0031] The first fiber layer is formed by interweaving coaxial fiber filaments, and the coaxial fiber filaments include a core layer and a shell layer, the core layer is made of a degradable non-water-soluble polymer, the shell layer is made of a degradable water-soluble polymer, and the shell layer is wrapped around the core layer;

[0032] The second fiber layer is formed by interweaving solid fiber filaments, and the solid fiber filaments are made of a degradable and water-insoluble polymer.

[0033] The present invention further provides a vascular stent system, comprising: the vascular stent described above and a balloon, wherein the vascular stent is sleeved outside the balloon and pressed onto the balloon.

[0034] With such a configuration, during the above preparation process, the degradable water-insoluble polymer and the degradable water-soluble polymer are processed into the vascular stent using the electrospinning process. When the vascular stent is transported and expanded in the body, the degradable water-soluble polymer portion of the fiber filament dissolves in the body fluid, and the slippage ability between the fibers is enhanced, thereby improving the expansion and over-expansion performance of the stent. The degradable material of the degradable water-insoluble polymer is almost unaffected, and the mechanical properties of the vascular stent itself are well maintained. By using innovative electrospinning process technology to prepare degradable stents, the pain point problem of poor over-expansion ability of polymer degradable stents is solved, and the success rate of the operation is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] FIG1 is a diagram showing the supporting force of the vascular stent according to various embodiments of the present invention. DETAILED DESCRIPTION

[0036] The following is a further detailed description of the vascular stent according to the present invention, with reference to the accompanying drawings and specific embodiments. The advantages and features of the present invention will become more apparent from the following description. It should be noted that the accompanying drawings are highly simplified and not to exact scale, and are intended solely to facilitate and clearly illustrate the embodiments of the present invention.

[0037] This embodiment provides a vascular stent.

[0038] The purpose of making the vascular stent in the present invention is to improve the circumferential support performance and over-expansion performance of the vascular stent: by regulating the type and proportion of materials, using new electrospinning and heat treatment to form the vascular stent, and combining the pressing and gripping process to form a vascular stent system, while ensuring that the vascular stent has a high support force, the expansion performance of the vascular stent is improved, helping doctors to more flexibly select the required stent specifications during surgery.

[0039] The materials of the vascular stent include degradable water-insoluble polymers and degradable water-soluble polymers.

[0040] The vascular stent is formed by interweaving a collection of fiber filaments made from the aforementioned materials. The fiber filaments are micro-nano fibers produced using electrospinning equipment. The fiber filaments can be coaxial or solid. Interweaving here refers to the cross-connection of the fiber filaments. Specific interweaving methods can include square interweaving, diamond interweaving, or other known interweaving methods.

[0041] Solid fiber filaments are made from the aforementioned degradable, water-insoluble polymer. To prepare the solid fiber filaments, the degradable, water-insoluble polymer is first dissolved in a solvent to form a first spinning solution. This first spinning solution is then introduced into an electrospinning apparatus, and the solid fiber filaments are extruded through a conventional nozzle of the electrospinning apparatus. The size of the solid fiber filaments can be adjusted by adjusting the process parameters of the electrospinning apparatus. These process parameters include polymer molecular weight, solution concentration, solvent type, voltage, injection speed, receiving distance, ambient temperature and humidity, and so on.

[0042] The coaxial fiber filament is made of the aforementioned degradable water-insoluble polymer and the degradable water-soluble polymer. The coaxial fiber filament is formed by extruding the two materials and comprises a core layer and a shell layer. The core layer is made of the degradable water-insoluble polymer, and the shell layer is made of the degradable water-soluble polymer, with the shell layer wrapped around the core layer.

[0043] In the process of preparing coaxial fiber yarns, a degradable non-water-soluble polymer is first dissolved in a solvent to form a first spinning solution, which is used to make a core layer; a degradable water-soluble polymer is dissolved in a solvent to form a second spinning solution, which is used to make a shell layer. A coaxial electrospinning nozzle is selected. The coaxial electrospinning nozzle is a composite cavity nozzle with a dual-channel cavity. The nozzle is prior art and will not be described here. The first spinning solution and the second spinning solution are connected to the electrospinning equipment, the second spinning solution is connected to the shell layer of the coaxial electrospinning nozzle, and the first spinning solution is connected to the core layer of the coaxial electrospinning nozzle. The parameters such as the spinning voltage, the injection speed of the core layer and the shell layer, the receiving distance, the ambient temperature and humidity are set to start coaxial electrospinning. The shell layer and the core layer will not mix before the spinneret solidifies. After applying a high-voltage electric field, the second solution is stretched and the first solution is extruded at the same time, forming a composite Taylor cone at the nozzle, and finally forming a composite coaxial fiber yarn with the shell layer wrapped around the core layer material. This results in composite micro-nano fibers with a water-soluble outer layer and a biodegradable inner layer. During the stent delivery and expansion process, the water-soluble outer layer of the coaxial fibers dissolves in body fluids, increasing the gaps between the fibers and making them easier to slide, significantly enhancing the stent's expansion capacity.

[0044] The electrospinning equipment has a receiving device, which is a cylindrical core shaft of a certain size and rotation speed. The fiber filaments are deposited on the surface of the core shaft in a certain arrangement, and finally a cylindrical fiber layer is obtained.

[0045] In the process of manufacturing a vascular stent, only coaxial fiber filaments can be generated by an electrospinning device, and the vascular stent can be formed only by interweaving the coaxial fiber filaments; or solid fiber filaments and coaxial fiber filaments can be alternately generated by an electrospinning device to form an alternately laid first fiber layer and a second fiber layer, and finally a vascular stent is manufactured.

[0046] In this embodiment, the vascular stent is composed of multiple layers of fiber filaments. The coaxial fiber filaments are interwoven to form a first fiber layer, and the solid fiber filaments are interwoven to form a second fiber layer. The first fiber layer and the second fiber layer are stacked to form the vascular stent.

[0047] The first fiber layer may be one layer or multiple layers, the second fiber layer may be one layer or multiple layers, and the first fiber layer and the second fiber layer are alternately arranged.

[0048] The vascular stent may include two fiber layers, which may be, for example, a first fiber layer and a second fiber layer from the inside to the outside, or respectively the second fiber layer and the first fiber layer from the inside to the outside.

[0049] The vascular stent may include three fiber layers, which may be, from inside to outside, for example, a first fiber layer, a second fiber layer, and a first fiber layer, or respectively, from inside to outside, a second fiber layer, a first fiber layer, and a second fiber layer.

[0050] During the stent manufacturing process, when forming the innermost fiber layer, the fiber filaments ejected by the electrospinning equipment are deposited on the surface of the core shaft in a certain arrangement to form the corresponding innermost fiber layer; when forming the second fiber layer, the fiber filaments ejected by the electrospinning equipment are deposited on the outer surface of the innermost fiber layer in a certain arrangement, and so on, layer by layer deposition finally forms the vascular stent.

[0051] Of course, the vascular stent may also include more fiber layers, which are not listed here one by one.

[0052] During the above preparation process, the concentrations of the first spinning solution and the second spinning solution are preferably between 1% and 20%. The relative molecular weight of the degradable water-insoluble polymer and the degradable water-soluble polymer preferably ranges from 1,000 to 1,000,000. The spinning voltage is 1-50 kV; the injection speed is 0.01-1 mm / min; the receiving distance is 50-300 mm; the ambient temperature is 18-30°C; the ambient humidity is 25-60%; the outer diameter of the receiving device is 0.1-5 mm; and the speed of the receiving device is 5-5,000 rpm. The specifications of the coaxial electrospinning nozzle can be 18G / 14G, 19G / 15G, 22G / 17G, 25G / 18G, 30G / 21G, etc.

[0053] In the above preparation process, the degradable non-water-soluble polymer includes one or a mixture and / or copolymer of two or more of polylactide (PLA), polyglycolide (PGA), polycaprolactone (PCL), polydioxanone (PPDO), polytrimethylene carbonate (PTMC), polyesteramides (PEA), polyhydroxyalkanoates (PHA), polyurethane (PU) and poly(lactide-glycolide) (PLGA8218).

[0054] In the above preparation process, the degradable water-soluble polymer includes polyvinyl alcohol (PVA), polyethylene glycol (PEG), polyethylene oxide (PEO), polyvinyl pyrrolidone (PVP), polyethylene imine (PEI), hyaluronic acid (HA), gelatin (GEL), collagen (COL), sodium alginate (SA) and a mixture and / or copolymer of one or more of hyaluronic acid.

[0055] In the above preparation process, both the degradable water-insoluble polymer and the degradable water-soluble polymer need to be dissolved in a solvent, and the solvent includes at least one of water, hexafluoroisopropanol, dichloromethane, chloroform, tetrahydrofuran, N,N-dimethylformamide, dimethyl sulfoxide, acetone, n-propyl acetate and n-butyl acetate.

[0056] By using a coaxial spinning process to process a degradable, water-insoluble polymer and a degradable, water-soluble polymer into a vascular stent, the water-soluble outer layer of the coaxial fiber dissolves in body fluids during delivery and expansion in the body, enhancing the slippage between the fibers and improving the stent's expansion and overexpansion performance. The degradable material in the core layer is virtually unaffected, and the mechanical properties of the vascular stent are well maintained. By using innovative coaxial electrospinning technology to prepare degradable stents, the pain point of poor overexpansion capacity of polymer degradable stents is resolved, improving the success rate of the procedure.

[0057] The appropriate material ratio can be selected based on actual expansion requirements and support performance to meet the expansion and support performance of the vascular stent. Preferably, the thickness of the first fiber layer accounts for 60%-80% of the total thickness of the vascular stent, and the thickness of the second fiber layer accounts for 20%-40% of the total thickness of the vascular stent.

[0058] Based on the above-mentioned vascular stent, this embodiment also provides a vascular stent system and preparation method. The vascular stent system includes a vascular stent and a balloon. The above-mentioned vascular stent is placed outside the balloon and compressed and gripped on the balloon to form the vascular stent system. The compression and gripping of the vascular stent is a necessary process before the vascular stent is delivered to the human body. The balloon is used to expand the vascular stent after the vascular stent system is delivered to the human body. Both the vascular stent compression and gripping and the balloon are existing technologies.

[0059] The manufacturing method of a vascular stent system includes stent preparation and stent compression. The stent preparation includes forming a fiber assembly into a stent using an electrospinning device and heat treatment. Whether to perform the heat treatment process can be determined based on the internal stresses experienced during stent production.

[0060] During the electrospinning process, the jet is drawn into fibers that solidify on the surface of a receiving device, resulting in a vascular stent. These stents typically have significant internal stress, and heat treatment is often required to eliminate this stress and improve mechanical properties. Heat treatment and a compression process can maintain and further enhance the mechanical properties of electrospun stents.

[0061] The heat treatment includes selecting a heat treatment core, placing the stent on the heat treatment core, and placing it in a heat treatment medium. The heat treatment medium is then heated, maintained, and cooled. The heating, maintaining, and cooling cycles can be repeated multiple times. The heat treatment medium includes one or a mixture of two or more of air, ethanol, ethylene glycol, and glycerol. Controlled heat treatment process parameters include initial temperature, heating rate, holding time, cooling rate, final temperature, and number of cycles.

[0062] The initial temperature is 25-150° C.; the heating rate is 0.1-10° C. / min; the holding time is 1-120 min; the cooling rate is 0.1-10° C. / min; the final temperature is 25-150° C.; and the number of cycles is 1-5 times.

[0063] After the heat treatment is completed, compression is performed to form a vascular stent system.

[0064] Crimping refers to crimping the vascular stent to a certain size using certain crimping parameters, and crimping the vascular stent onto the balloon to meet the size requirements for delivery within the human body.

[0065] During the crimping process, the stent is placed in a crimping medium to ensure its mechanical properties. By controlling parameters such as crimping speed and medium temperature, the stent is crimped while maintaining optimal mechanical properties.

[0066] The crimping parameters include the type of crimping medium, crimping rate, crimping medium temperature, holding time, holding temperature, etc.

[0067] The pressing medium includes one of air, ethanol, ethylene glycol, and glycerol, or a mixture of two or more thereof.

[0068] The crimping rate is 0.01-20 mm / s; the crimping medium temperature is 25-80°C; the holding time is 0-999s; and the holding temperature is 25-80°C.

[0069] During the actual crimping process, the heat-treated stent is placed in a crimping machine and the corresponding crimping parameters are adjusted for crimping. The crimping method is conventional and will not be described in detail here. The present invention differs in the use and selection of the crimping medium.

[0070] By using a coaxial spinning process to process a degradable non-water-soluble polymer and a degradable water-soluble polymer into a vascular stent, and using a heat treatment and a compression grip process, a vascular stent system with excellent over-expansion performance and support performance can be finally obtained.

[0071] The invention describes the manufacturing process of the vascular stent and the vascular stent system through the following multiple embodiments.

[0072] The present invention provides fifteen embodiments, which are divided into three groups in the following implementation:

[0073] Wherein Example 1, Example 1 Comparative Example 1, Example 1 Comparative Example 2, Example 1 Comparative Example 3 and Example 1 Comparative Example 4 are a group;

[0074] Example 2, Example 2 Comparative Example 1, Example 2 Comparative Example 2, Example 2 Comparative Example 3 and Example 2 Comparative Example 4 are a group;

[0075] Example 3, Example 3 Control Example 1, Example 3 Control Example 2, Example 3 Control Example 3 and Example 3 Control Example 4 are a group.

[0076] In addition, the vascular stents in Example 1, Example 2, and Example 3 are all made of only solid fiber filaments, that is, they are made of only degradable and water-insoluble polymers. The above three embodiments serve as existing vascular stents and serve as a comparison of mechanical and expansion performance; the remaining embodiments all use the preparation method of the present invention to prepare vascular stents.

[0077] Example 1:

[0078] S1: Preparation of fiber aggregate-shaped vascular scaffolds

[0079] PLA (molecular weight 250,000-350,000) was dissolved in a 7:3 (volume ratio) mixture of chloroform and N,N-dimethylformamide to create a first solution with a mass fraction of 6-10%. PEG (molecular weight 2,000-8,000) was dissolved in water to create a second solution with a mass fraction of 1-4%. The first solution was injected into the core layer of a coaxial electrospinning nozzle, while the second solution was injected into the shell layer of the nozzle.

[0080] Electrospinning was performed using an electrospinning device using the following parameters: 22G / 17G coaxial electrospinning nozzle, 6-8kV spinning voltage, 0.20-0.30mm / min shell injection speed, 0.10-0.20mm / min core injection speed, 80-100mm receiving distance, 23±1°C ambient temperature, 30±5% ambient humidity. The outer diameter of the receiving device was 2.5mm, and the receiving device rotation speed was 1000-1500rpm.

[0081] A first fiber layer is deposited on the receiving device, and the total thickness of the vascular stent is 100 μm.

[0082] S2: Heat treatment

[0083] The stent is placed on the heat treatment liner and placed in the air, and the heat treatment medium is heated, kept warm, and cooled. The heating, keeping warm, and cooling cycles can be repeated multiple times.

[0084] The heat treatment was performed using the following parameters: a 2.5 mm core, an initial temperature of 25-28°C, a heating rate of 1.0-1.5°C / min, a holding time of 10-15 min, a cooling rate of 5-6°C / min, and a final temperature of 25-28°C. The number of cycles was one.

[0085] S3: Press Grip

[0086] The stent is pressed onto the balloon to meet the dimensions required for delivery within the human body. During the pressing process, the stent is placed in a pressing medium to ensure the mechanical properties of the stent.

[0087] The following parameters were used for crimping: the crimping medium was air, the crimping rate was 0.1-0.2 mm / s, the crimping medium temperature was 60-70°C, the holding time was 300s, and the holding temperature was 60-70°C.

[0088] Example 1 Comparative Example 1:

[0089] This control example is the same as the first solution in Example 1, and only the vascular stent prepared using the first solution is used. Therefore, the vascular stent in this example only has solid fiber filaments, and the vascular stent is only made of degradable non-water-soluble polymer.

[0090] S1: Preparation of fiber aggregate-shaped vascular scaffolds

[0091] PLA (molecular weight 250,000-350,000) was dissolved in a 7:3 (volume ratio) mixture of chloroform and N,N-dimethylformamide to prepare a first solution with a mass fraction of 6-10%. Electrospinning was performed using an electrospinning device using the following parameters: 22G electrospinning nozzle, 6-8kV spinning voltage, 0.10-0.20mm / min injection speed, 80-100mm receiving distance, ambient temperature of 23±1°C, and humidity of 30±5%. The receiving device had a size of 2.5mm and a rotation speed of 1000-1500rpm.

[0092] A second fiber layer is deposited on the receiving device to form a vascular stent, and the total thickness of the vascular stent is 100 μm.

[0093] S2: Heat treatment

[0094] The stent is placed on the heat treatment liner and placed in the air, and the heat treatment medium is heated, kept warm, and cooled. The heating, keeping warm, and cooling cycles can be repeated multiple times.

[0095] The heat treatment was performed using the following parameters: a 2.5 mm core, an initial temperature of 25-28°C, a heating rate of 1.0-1.5°C / min, a holding time of 10-15 min, a cooling rate of 5-6°C / min, and a final temperature of 25-28°C. The number of cycles was one.

[0096] S3: Press Grip

[0097] The stent is pressed onto the balloon to meet the dimensions required for delivery within the human body. During the pressing process, the stent is placed in a pressing medium to ensure the mechanical properties of the stent.

[0098] The following parameters were used for crimping: the crimping medium was air, the crimping rate was 0.1-0.2 mm / s, the crimping medium temperature was 60-70°C, the holding time was 300s, and the holding temperature was 60-70°C.

[0099] Example 1 Comparative Example 2:

[0100] S1: Preparation of fiber aggregate-shaped vascular scaffolds

[0101] PLA (molecular weight 250,000-350,000) was dissolved in a mixture of chloroform and N,N-dimethylformamide (7:3 by volume) to prepare a first solution with a mass fraction of 6-10%. PEG (molecular weight 2,000-8,000) was dissolved in water to prepare a second solution with a mass fraction of 1-4%. Electrospinning was performed using an electrospinning device using the following parameters: 22G / 17G coaxial electrospinning nozzles, a spinning voltage of 6-8 kV, a shell injection speed of 0.20-0.30 mm / min, a core injection speed of 0.10-0.20 mm / min, a receiving distance of 80-100 mm, an ambient temperature of 23±1°C, and an ambient humidity of 30±5%. The outer diameter of the receiving device was 2.5 mm, and the receiving rotation speed was 1000-1500 rpm. A first fiber layer with a thickness of 20 μm was deposited on the receiving device.

[0102] PLA (molecular weight 250,000-350,000) was dissolved in a mixture of chloroform and N,N-dimethylformamide (7:3 by volume) to prepare a first solution with a mass fraction of 6-10%. Electrospinning was performed using an electrospinning device using the following parameters: 22G electrospinning nozzle, 6-8kV spinning voltage, 0.10-0.20mm / min injection speed, 80-100mm receiving distance, 23±1°C ambient temperature, and 30±5% humidity. The receiving device had an outer diameter of 2.5mm and a rotation speed of 1000-1500rpm. A second fiber layer was deposited on the receiving device, attached to the first fiber layer, with a spun thickness of 80µm.

[0103] The total thickness of the vascular stent is 100um.

[0104] S2: Heat treatment

[0105] The stent is placed on the heat treatment liner and placed in the air, and the heat treatment medium is heated, kept warm, and cooled. The heating, keeping warm, and cooling cycles can be repeated multiple times.

[0106] The heat treatment was performed using the following parameters: a 2.5 mm core, an initial temperature of 25-28°C, a heating rate of 1.0-1.5°C / min, a holding time of 10-15 min, a cooling rate of 5-6°C / min, and a final temperature of 25-28°C. The number of cycles was one.

[0107] S3: Press Grip

[0108] The stent is pressed onto the balloon to meet the dimensions required for delivery within the human body. During the pressing process, the stent is placed in a pressing medium to ensure the mechanical properties of the stent.

[0109] The following parameters were used for crimping: the crimping medium was air, the crimping rate was 0.1-0.2 mm / s, the crimping medium temperature was 60-70°C, the holding time was 300s, and the holding temperature was 60-70°C.

[0110] Example 1 Comparative Example 3:

[0111] S1: Preparation of fiber aggregate-shaped vascular scaffolds

[0112] PLA (molecular weight 250,000-350,000) was dissolved in a mixture of chloroform and N,N-dimethylformamide (7:3 by volume) to prepare a first solution with a mass fraction of 6-10%. PEG (molecular weight 2,000-8,000) was dissolved in water to prepare a second solution with a mass fraction of 1-4%. Electrospinning was performed using an electrospinning device using the following parameters: 22G / 17G coaxial electrospinning nozzles, a spinning voltage of 6-8 kV, a shell injection speed of 0.20-0.30 mm / min, a core injection speed of 0.10-0.20 mm / min, a receiving distance of 80-100 mm, an ambient temperature of 23±1°C, and an ambient humidity of 30±5%. The outer diameter of the receiving device was 2.5 mm, and the receiving rotation speed was 1000-1500 rpm. A first fiber layer with a thickness of 20 μm was deposited on the receiving device.

[0113] PLA (molecular weight 250,000-350,000) was dissolved in a 7:3 (volume ratio) mixture of chloroform and N,N-dimethylformamide to produce a 6-10% solution. Electrospinning was performed using an electrospinning device using the following parameters: a 22G electrospinning nozzle, a spinning voltage of 6-8 kV, an injection speed of 0.10-0.20 mm / min, a receiving distance of 80-100 mm, an ambient temperature of 23 ± 1°C, and an ambient humidity of 30 ± 5%. The receiving device had an outer diameter of 2.5 mm and a rotation speed of 1000-1500 rpm. A second fiber layer was deposited on the receiving device, attached to the first fiber layer, with a spun thickness of 80 μm.

[0114] The total thickness of the vascular stent is 100um.

[0115] S2: Press Grip

[0116] The stent is pressed onto the balloon to meet the dimensions required for delivery within the human body. During the pressing process, the stent is placed in a pressing medium to ensure the mechanical properties of the stent.

[0117] The following parameters were used for crimping: the crimping medium was air, the crimping rate was 0.1-0.2 mm / s, the crimping medium temperature was 60-70°C, the holding time was 300s, and the holding temperature was 60-70°C.

[0118] Example 1 Comparative Example 4:

[0119] S1: Preparation of fiber aggregate-shaped vascular scaffolds

[0120] PLA (molecular weight 250,000-350,000) was dissolved in a mixture of chloroform and N,N-dimethylformamide (7:3 by volume) to prepare a first solution with a mass fraction of 6-10%. PEG (molecular weight 2,000-8,000) was dissolved in water to prepare a second solution with a mass fraction of 1-4%. Electrospinning was performed using an electrospinning device using the following parameters: 22G / 17G coaxial electrospinning nozzles, a spinning voltage of 6-8 kV, a shell injection speed of 0.20-0.30 mm / min, a core injection speed of 0.10-0.20 mm / min, a receiving distance of 80-100 mm, an ambient temperature of 23±1°C, and an ambient humidity of 30±5%. The outer diameter of the receiving device was 2.5 mm, and the receiving rotation speed was 1000-1500 rpm. A first fiber layer with a thickness of 20 μm was deposited on the receiving device.

[0121] PLA (molecular weight 250,000-350,000) was dissolved in a 7:3 (volume ratio) mixture of chloroform and N,N-dimethylformamide to produce a 6-10% solution. Electrospinning was performed using an electrospinning device using the following parameters: a 22G electrospinning nozzle, a spinning voltage of 6-8 kV, an injection speed of 0.10-0.20 mm / min, a receiving distance of 80-100 mm, an ambient temperature of 23 ± 1°C, and an ambient humidity of 30 ± 5%. The receiving device had an outer diameter of 2.5 mm and a rotation speed of 1000-1500 rpm. A second fiber layer was deposited on the receiving device, attached to the first fiber layer, with a spun thickness of 80 μm.

[0122] The total thickness of the vascular stent is 100um.

[0123] S2: Heat treatment

[0124] The stent is placed on the heat treatment liner and placed in the air, and the heat treatment medium is heated, kept warm, and cooled. The heating, keeping warm, and cooling cycles can be repeated multiple times.

[0125] The heat treatment was performed using the following parameters: a 2.5 mm core, an initial temperature of 25-28°C, a heating rate of 1.0-1.5°C / min, a holding time of 10-15 min, a cooling rate of 5-6°C / min, and a final temperature of 25-28°C. The number of cycles was one.

[0126] Example 2:

[0127] S1: Preparation of fiber aggregate-shaped vascular scaffolds

[0128] PLA (molecular weight 350,000-450,000) and PCL (molecular weight 70,000-90,000) were dissolved in hexafluoroisopropanol at a mass ratio of 9:1 to prepare a first solution with a mass fraction of 12-16%. PVA (molecular weight 4-10,000) was dissolved in water to prepare a second solution with a mass fraction of 8-11%. Electrospinning was performed using an electrospinning device using the following parameters: 19G / 15G coaxial electrospinning nozzle, 12-14kV spinning voltage, 0.45-0.55mm / min shell injection speed, 0.15-0.25mm / min core injection speed, 120-140mm receiving distance, 22±1°C ambient temperature, 35±5% humidity. The receiving device had an outer diameter of 2.5mm and a rotating speed of 2000-2500rpm.

[0129] A first fiber layer is deposited on the receiving device to form a vascular stent, and the total thickness of the vascular stent is 100 μm.

[0130] S2: Heat treatment

[0131] The stent is placed on the heat treatment liner and placed in the air, and the heat treatment medium is heated, kept warm, and cooled. The heating, keeping warm, and cooling cycles can be repeated multiple times.

[0132] The heat treatment was performed using the following parameters: a 1.5 mm outer diameter balloon as the heat treatment core, an initial temperature of 27-30°C, a heating rate of 0.5-1.0°C / min, a holding time of 60-65 min, a cooling rate of 9-10°C / min, and a final temperature of 27-30°C. The number of cycles was three.

[0133] S3: Press Grip

[0134] The stent is pressed onto the balloon to meet the dimensions required for delivery within the human body. During the pressing process, the stent is placed in a pressing medium to ensure the mechanical properties of the stent.

[0135] The following parameters are used for crimping: the crimping medium is air, the crimping rate is 0.2-0.3 mm / s, the crimping medium temperature is 25-35°C, the holding time is 120s, and the holding temperature is 25-35°C.

[0136] Example 2 Comparative Example 1:

[0137] This control example is the same as the first solution in Example 2, and only the vascular stent prepared using the first solution is used: therefore, the vascular stent in this example only has solid fiber filaments, and the vascular stent is only made of degradable non-water-soluble polymer.

[0138] S1: Preparation of micro-nanofiber aggregates

[0139] PLA (molecular weight 350,000-450,000) and PCL (molecular weight 70,000-90,000) were dissolved in hexafluoroisopropanol at a mass ratio of 9:1 to prepare a first solution with a mass fraction of 12-16%. Electrospinning was performed using an electrospinning device using the following parameters: 19G nozzle, spinning voltage of 12-14 kV, injection speed of 0.15-0.25 mm / min, receiving distance of 120-140 mm, ambient temperature of 22±1°C, and humidity of 35±5%. The receiving device had a size of 2.5 mm and the rotation speed was 2000-2500 rpm. A second fiber layer was deposited on the receiving device to form the vascular stent, with a total thickness of 100 μm.

[0140] S2: Heat treatment

[0141] The stent is placed on the heat treatment liner and placed in the air, and the heat treatment medium is heated, kept warm, and cooled. The heating, keeping warm, and cooling cycles can be repeated multiple times.

[0142] The heat treatment was performed using the following parameters: a 1.5 mm outer diameter balloon as the heat treatment core, an initial temperature of 27-30°C, a heating rate of 0.5-1.0°C / min, a holding time of 60-65 min, a cooling rate of 9-10°C / min, and a final temperature of 27-30°C. The number of cycles was three.

[0143] S3: Press Grip

[0144] The stent is pressed onto the balloon to meet the dimensions required for delivery within the human body. During the pressing process, the stent is placed in a pressing medium to ensure the mechanical properties of the stent.

[0145] The following parameters are used for crimping: the crimping medium is air, the crimping rate is 0.2-0.3 mm / s, the crimping medium temperature is 25-35°C, the holding time is 120s, and the holding temperature is 25-35°C.

[0146] Example 2 Control Example 2.

[0147] S1: Preparation of fiber aggregate-shaped vascular scaffolds

[0148] PLA (molecular weight 350,000-450,000) and PCL (molecular weight 70,000-90,000) were dissolved in hexafluoroisopropanol at a mass ratio of 9:1 to prepare a first solution with a mass fraction of 12-16%. PVA (molecular weight 4-10,000) was dissolved in water to prepare a second solution with a mass fraction of 8-11%. Electrospinning was performed using an electrospinning device using the following parameters: 19G / 15G coaxial electrospinning nozzles, a spinning voltage of 12-14 kV, a shell injection speed of 0.45-0.55 mm / min, a core injection speed of 0.15-0.25 mm / min, a receiving distance of 120-140 mm, an ambient temperature of 22±1°C, and an ambient humidity of 35±5%. The outer diameter of the receiving device was 2.5 mm, and the receiving device rotation speed was 2000-2500 rpm. A first fiber layer with a thickness of 20 μm was deposited on the receiving device.

[0149] PLA (molecular weight 350,000-450,000) and PCL (molecular weight 70,000-90,000) were dissolved in hexafluoroisopropanol at a mass ratio of 9:1 to produce a 12-16% solution. Electrospinning was performed using an electrospinning device using the following parameters: 19G electrospinning nozzle, 12-14kV spinning voltage, 0.15-0.25mm / min injection speed, 120-140mm receiving distance, 22±1°C ambient temperature, and 35±5% humidity. The receiving device had an outer diameter of 2.5mm and a rotation speed of 2000-2500rpm. A second fiber layer, 60µm thick, was deposited on the receiving device and attached to the first fiber layer.

[0150] PLA with a molecular weight of 350,000-450,000 and PCL with a molecular weight of 70,000-90,000 were dissolved in hexafluoroisopropanol at a mass ratio of 9:1 to prepare a first solution with a mass fraction of 12-16%. PVA with a molecular weight of 4,000-10,000 was dissolved in water to prepare a second solution with a mass fraction of 8-11%. Electrospinning was performed using an electrospinning device using the following parameters: coaxial electrospinning nozzle specifications of 19G / 15G, spinning voltage of 12-14kV, shell layer injection speed of 0.45-0.55mm / min, core layer injection speed of 0.15-0.25mm / min, receiving distance of 120-140mm, ambient temperature of 22±1°C, and ambient humidity of 35±5%. The outer diameter of the receiving device was 2.5mm, and the rotation speed of the receiving device was 2000-2500rpm. The first fiber layer was further deposited on the receiving device, and the first fiber layer was attached to the second fiber layer. This first fiber layer was 20um.

[0151] At this time, the vascular stent forms a three-layer composite structure consisting of a first fiber layer, a second fiber layer and a first fiber layer from the inside to the outside, and the total thickness of the vascular stent is 100 μm.

[0152] S2: Heat treatment

[0153] The stent is placed on the heat treatment liner and placed in the air, and the heat treatment medium is heated, kept warm, and cooled. The heating, keeping warm, and cooling cycles can be repeated multiple times.

[0154] The heat treatment was performed using the following parameters: a 1.5 mm outer diameter balloon as the heat treatment core, an initial temperature of 27-30°C, a heating rate of 0.5-1.0°C / min, a holding time of 60-65 min, a cooling rate of 9-10°C / min, and a final temperature of 27-30°C. The number of cycles was three.

[0155] S3: Press Grip

[0156] The stent is pressed onto the balloon to meet the dimensions required for delivery within the human body. During the pressing process, the stent is placed in a pressing medium to ensure the mechanical properties of the stent.

[0157] The following parameters are used for crimping: the crimping medium is air, the crimping rate is 0.2-0.3 mm / s, the crimping medium temperature is 25-35°C, the holding time is 120s, and the holding temperature is 25-35°C.

[0158] Example 2 Comparative Example 3:

[0159] S1: Preparation of fiber aggregate-shaped vascular scaffolds

[0160] PLA (molecular weight 350,000-450,000) and PCL (molecular weight 70,000-90,000) were dissolved in hexafluoroisopropanol at a mass ratio of 9:1 to prepare a first solution with a mass fraction of 12-16%. PVA (molecular weight 4-10,000) was dissolved in water to prepare a second solution with a mass fraction of 8-11%. Electrospinning was performed using an electrospinning device using the following parameters: 19G / 15G coaxial electrospinning nozzles, a spinning voltage of 12-14 kV, a shell injection speed of 0.45-0.55 mm / min, a core injection speed of 0.15-0.25 mm / min, a receiving distance of 120-140 mm, an ambient temperature of 22±1°C, and an ambient humidity of 35±5%. The outer diameter of the receiving device was 2.5 mm, and the receiving device rotation speed was 2000-2500 rpm. A first fiber layer with a thickness of 20 μm was deposited on the receiving device.

[0161] PLA (molecular weight 350,000-450,000) and PCL (molecular weight 70,000-90,000) were dissolved in hexafluoroisopropanol at a mass ratio of 9:1 to produce a 12-16% solution. Electrospinning was performed using an electrospinning device using the following parameters: 19G electrospinning nozzle, 12-14kV spinning voltage, 0.15-0.25mm / min injection speed, 120-140mm receiving distance, 22±1°C ambient temperature, and 35±5% humidity. The receiving device had an outer diameter of 2.5mm and a rotation speed of 2000-2500rpm. A second fiber layer, 60µm thick, was deposited on the receiving device and attached to the first fiber layer.

[0162] PLA (molecular weight 350,000-450,000) and PCL (molecular weight 70,000-90,000) were dissolved in hexafluoroisopropanol at a mass ratio of 9:1 to prepare a first solution with a mass fraction of 12-16%. PVA (molecular weight 4-10,000) was dissolved in water to prepare a second solution with a mass fraction of 8-11%. Electrospinning was performed using an electrospinning device using the following parameters: 19G / 15G coaxial electrospinning nozzle, 12-14kV spinning voltage, 0.45-0.55mm / min shell injection speed, 0.15-0.25mm / min core injection speed, 120-140mm receiving distance, 22±1°C ambient temperature, 35±5% humidity. The outer diameter of the receiving device was 2.5mm, and the receiving device rotation speed was 2000-2500rpm. The spinning thickness was 20µm. The first fiber layer continues to be deposited on the receiving device. The first fiber layer is attached to the second fiber layer. The first fiber layer is 20 μm.

[0163] At this time, the vascular stent forms a three-layer composite structure consisting of a first fiber layer, a second fiber layer and a first fiber layer from the inside to the outside, and the total thickness of the vascular stent is 100 μm.

[0164] S2: Press Grip

[0165] The stent is pressed onto the balloon to meet the dimensions required for delivery within the human body. During the pressing process, the stent is placed in a pressing medium to ensure the mechanical properties of the stent.

[0166] The following parameters are used for crimping: the crimping medium is air, the crimping rate is 0.2-0.3 mm / s, the crimping medium temperature is 25-35°C, the holding time is 120s, and the holding temperature is 25-35°C.

[0167] Example 2 Comparative Example 4:

[0168] S1: Preparation of fiber aggregate-shaped vascular scaffolds

[0169] PLA (molecular weight 350,000-450,000) and PCL (molecular weight 70,000-90,000) were dissolved in hexafluoroisopropanol at a mass ratio of 9:1 to prepare a first solution with a mass fraction of 12-16%. PVA (molecular weight 4-10,000) was dissolved in water to prepare a second solution with a mass fraction of 8-11%. Electrospinning was performed using an electrospinning device using the following parameters: 19G / 15G coaxial electrospinning nozzles, a spinning voltage of 12-14 kV, a shell injection speed of 0.45-0.55 mm / min, a core injection speed of 0.15-0.25 mm / min, a receiving distance of 120-140 mm, an ambient temperature of 22±1°C, and an ambient humidity of 35±5%. The outer diameter of the receiving device was 2.5 mm, and the receiving device rotation speed was 2000-2500 rpm. A first fiber layer with a thickness of 20 μm was deposited on the receiving device.

[0170] PLA (molecular weight 350,000-450,000) and PCL (molecular weight 70,000-90,000) were dissolved in hexafluoroisopropanol at a mass ratio of 9:1 to produce a 12-16% solution. Electrospinning was performed using an electrospinning device using the following parameters: 19G electrospinning nozzle, 12-14kV spinning voltage, 0.15-0.25mm / min injection speed, 120-140mm receiving distance, 22±1°C ambient temperature, and 35±5% humidity. The receiving device had an outer diameter of 2.5mm and a rotation speed of 2000-2500rpm. A second fiber layer, 60µm thick, was deposited on the receiving device and attached to the first fiber layer.

[0171] PLA (molecular weight 350,000-450,000) and PCL (molecular weight 70,000-90,000) were dissolved in hexafluoroisopropanol at a mass ratio of 9:1 to prepare a first solution with a mass fraction of 12-16%. PVA (molecular weight 4-10,000) was dissolved in water to prepare a second solution with a mass fraction of 8-11%. Electrospinning was performed using an electrospinning device using the following parameters: 19G / 15G coaxial electrospinning nozzle, 12-14kV spinning voltage, 0.45-0.55mm / min shell injection speed, 0.15-0.25mm / min core injection speed, 120-140mm receiving distance, 22±1°C ambient temperature, 35±5% humidity. The outer diameter of the receiving device was 2.5mm, and the receiving device rotation speed was 2000-2500rpm. The spinning thickness was 20µm. The first fiber layer continues to be deposited on the receiving device. The first fiber layer is attached to the second fiber layer. The first fiber layer is 20 μm.

[0172] At this time, the vascular stent forms a three-layer composite structure consisting of a first fiber layer, a second fiber layer and a first fiber layer from the inside to the outside, and the total thickness of the vascular stent is 100 μm.

[0173] S2: Heat treatment

[0174] The stent is placed on the heat treatment liner and placed in the air, and the heat treatment medium is heated, kept warm, and cooled. The heating, keeping warm, and cooling cycles can be repeated multiple times.

[0175] The heat treatment was performed using the following parameters: a 1.5 mm outer diameter balloon as the heat treatment core, an initial temperature of 27-30°C, a heating rate of 0.5-1.0°C / min, a holding time of 60-65 min, a cooling rate of 9-10°C / min, and a final temperature of 27-30°C. The number of cycles was three.

[0176] Example 3:

[0177] S1: Preparation of fiber aggregate-shaped vascular scaffolds

[0178] PLGA8218 (molecular weight 200,000-300,000) was dissolved in hexafluoroisopropanol to prepare a first solution with a mass fraction of 4-6%. Hyaluronic acid (molecular weight 30,000-45,000) was dissolved in water to prepare a second solution with a mass fraction of 2-5%. Electrospinning was performed using an electrospinning device using the following parameters: 18G / 14G coaxial electrospinning nozzle, 20-22kV spinning voltage, shell injection speed of 0.10-0.15mm / min, core injection speed of 0.05-0.15mm / min, receiving distance of 60-80mm, ambient temperature of 25±1°C, and ambient humidity of 45±5%. The outer diameter of the receiving device was 2.5mm, and the receiving device rotation speed was 4500-5000rpm.

[0179] A first fiber layer is deposited on the receiving device, and the total thickness of the vascular stent is 100 μm.

[0180] S2: Heat treatment

[0181] The stent is placed on the heat treatment liner and placed in the air, and the heat treatment medium is heated, kept warm, and cooled. The heating, keeping warm, and cooling cycles can be repeated multiple times.

[0182] The heat treatment was performed using the following parameters: a 2.5 mm outer diameter core, an initial temperature of 19-22°C, a heating rate of 2.0-2.5°C / min, a holding time of 5-10 min, a cooling rate of 7-8°C / min, and a final temperature of 19-22°C. The number of cycles was 2.

[0183] S3: Press Grip

[0184] The stent is pressed onto the balloon to meet the dimensions required for delivery within the human body. During the pressing process, the stent is placed in a pressing medium to ensure the mechanical properties of the stent.

[0185] The following parameters are used for crimping: the crimping medium is a mixed solution of ethanol and ethylene glycol with a volume ratio of 7 to 3, the crimping rate is 0.02-0.12 mm / s, the crimping medium temperature is 45-55°C, the holding time is 30s, and the holding temperature is 45-55°C.

[0186] Example 3 Comparative Example 1:

[0187] This control example is the same as the first solution in Example 3, and only the vascular stent prepared using the first solution is used: therefore, the vascular stent in this example only has solid fiber filaments, and the vascular stent is only made of degradable non-water-soluble polymer.

[0188] S1: Preparation of micro-nanofiber aggregates

[0189] PLGA8218 (molecular weight 200,000-300,000) was dissolved in hexafluoroisopropanol to prepare a first solution with a mass fraction of 4-6%. Electrospinning was performed using an electrospinning apparatus using the following parameters: 18G electrospinning nozzle, 20-22 kV spinning voltage, 0.05-0.15 mm / min injection speed, 60-80 mm receiving distance, 25 ± 1°C ambient temperature, 45 ± 5% humidity, 2.5 mm receiving device size, and 4500-5000 rpm rotation speed.

[0190] A second fiber layer is deposited on the receiving device to form a vascular stent, and the total thickness of the vascular stent is 100 μm.

[0191] S2: Heat treatment

[0192] The stent is placed on the heat treatment liner and placed in the air, and the heat treatment medium is heated, kept warm, and cooled. The heating, keeping warm, and cooling cycles can be repeated multiple times.

[0193] The heat treatment was performed using the following parameters: a 2.5 mm outer diameter core, an initial temperature of 19-22°C, a heating rate of 2.0-2.5°C / min, a holding time of 5-10 min, a cooling rate of 7-8°C / min, and a final temperature of 19-22°C. The number of cycles was 2.

[0194] S3: Press Grip

[0195] The stent is pressed onto the balloon to meet the dimensions required for delivery within the human body. During the pressing process, the stent is placed in a pressing medium to ensure the mechanical properties of the stent.

[0196] The following parameters are used for crimping: the crimping medium is a mixed solution of ethanol and ethylene glycol with a volume ratio of 7 to 3, the crimping rate is 0.02-0.12 mm / s, the crimping medium temperature is 45-55°C, the holding time is 30s, and the holding temperature is 45-55°C.

[0197] Example 3 Comparative Example 2:

[0198] S1: Preparation of fiber aggregate-shaped vascular scaffolds

[0199] PLGA8218 (molecular weight 200,000-300,000) was dissolved in hexafluoroisopropanol to prepare a first solution with a mass fraction of 4-6%. Hyaluronic acid (molecular weight 30,000-45,000) was dissolved in water to prepare a second solution with a mass fraction of 2-5%. Electrospinning was performed using an electrospinning device using the following parameters: 18G / 14G coaxial electrospinning nozzles, a spinning voltage of 20-22 kV, a shell injection speed of 0.10-0.15 mm / min, a core injection speed of 0.05-0.15 mm / min, a receiving distance of 60-80 mm, an ambient temperature of 25±1°C, and an ambient humidity of 45±5%. The receiving device had an outer diameter of 2.5 mm and a rotation speed of 4500-5000 rpm. A first fiber layer with a thickness of 10 μm was deposited on the receiving device.

[0200] PLGA8218 (molecular weight 200,000-300,000) was dissolved in hexafluoroisopropanol to prepare a 4-6% solution. Electrospinning was performed using an 18G electrospinning nozzle, a spinning voltage of 20-22 kV, an injection speed of 0.05-0.15 mm / min, a receiving distance of 60-80 mm, an ambient temperature of 25 ± 1°C, and an ambient humidity of 45 ± 5%. The receiving device had an outer diameter of 2.5 mm and a rotation speed of 4500-5000 rpm. A second fiber layer was deposited on the receiving device, attached to the first fiber layer, with a thickness of 80 μm.

[0201] PLGA8218 (molecular weight 200,000-300,000) was dissolved in hexafluoroisopropanol to prepare a first solution with a mass fraction of 4-6%. Hyaluronic acid (molecular weight 30,000-45,000) was dissolved in water to prepare a second solution with a mass fraction of 2-5%. Electrospinning was performed using an electrospinning device using the following parameters: 18G / 14G coaxial electrospinning nozzles, a spinning voltage of 20-22 kV, a shell injection speed of 0.10-0.15 mm / min, a core injection speed of 0.05-0.15 mm / min, a receiving distance of 60-80 mm, an ambient temperature of 25±1°C, and an ambient humidity of 45±5%. The outer diameter of the receiving device was 2.5 mm, and the receiving device rotation speed was 4500-5000 rpm. The first fiber layer was then deposited on the receiving device, attached to the second fiber layer. The first fiber layer was 10 μm thick.

[0202] At this time, the vascular stent forms a three-layer composite structure consisting of a first fiber layer, a second fiber layer and a first fiber layer from the inside to the outside, and the total thickness of the vascular stent is 100 μm.

[0203] S2: Heat treatment

[0204] The stent is placed on the heat treatment liner and placed in the air, and the heat treatment medium is heated, kept warm, and cooled. The heating, keeping warm, and cooling cycles can be repeated multiple times.

[0205] The heat treatment was performed using the following parameters: a 2.5 mm outer diameter core, an initial temperature of 19-22°C, a heating rate of 2.0-2.5°C / min, a holding time of 5-10 min, a cooling rate of 7-8°C / min, and a final temperature of 19-22°C. The number of cycles was 2.

[0206] S3: Press Grip

[0207] The stent is pressed onto the balloon to meet the dimensions required for delivery within the human body. During the pressing process, the stent is placed in a pressing medium to ensure the mechanical properties of the stent.

[0208] The following parameters are used for crimping: the crimping medium is a mixed solution of ethanol and ethylene glycol with a volume ratio of 7 to 3, the crimping rate is 0.02-0.12 mm / s, the crimping medium temperature is 45-55°C, the holding time is 30s, and the holding temperature is 45-55°C.

[0209] Example 3 Comparative Example 3:

[0210] S1: Preparation of fiber aggregate-shaped vascular scaffolds

[0211] PLGA8218 (molecular weight 200,000-300,000) was dissolved in hexafluoroisopropanol to prepare a first solution with a mass fraction of 4-6%. Hyaluronic acid (molecular weight 30,000-45,000) was dissolved in water to prepare a second solution with a mass fraction of 2-5%. Electrospinning was performed using an electrospinning device using the following parameters: 18G / 14G coaxial electrospinning nozzles, a spinning voltage of 20-22 kV, a shell injection speed of 0.10-0.15 mm / min, a core injection speed of 0.05-0.15 mm / min, a receiving distance of 60-80 mm, an ambient temperature of 25±1°C, and an ambient humidity of 45±5%. The receiving device had an outer diameter of 2.5 mm and a rotation speed of 4500-5000 rpm. A first fiber layer with a thickness of 10 μm was deposited on the receiving device.

[0212] PLGA8218 (molecular weight 200,000-300,000) was dissolved in hexafluoroisopropanol to prepare a 4-6% solution. Electrospinning was performed using an 18G electrospinning nozzle, a spinning voltage of 20-22 kV, an injection speed of 0.05-0.15 mm / min, a receiving distance of 60-80 mm, an ambient temperature of 25 ± 1°C, and an ambient humidity of 45 ± 5%. The receiving device had an outer diameter of 2.5 mm and a rotation speed of 4500-5000 rpm. A second fiber layer was deposited on the receiving device, attached to the first fiber layer, with a thickness of 80 μm.

[0213] PLGA8218 (molecular weight 200,000-300,000) was dissolved in hexafluoroisopropanol to prepare a first solution with a mass fraction of 4-6%. Hyaluronic acid (molecular weight 30,000-45,000) was dissolved in water to prepare a second solution with a mass fraction of 2-5%. Electrospinning was performed using an electrospinning device using the following parameters: 18G / 14G coaxial electrospinning nozzles, a spinning voltage of 20-22 kV, a shell injection speed of 0.10-0.15 mm / min, a core injection speed of 0.05-0.15 mm / min, a receiving distance of 60-80 mm, an ambient temperature of 25±1°C, and an ambient humidity of 45±5%. The outer diameter of the receiving device was 2.5 mm, and the receiving device rotation speed was 4500-5000 rpm. The first fiber layer was then deposited on the receiving device, attached to the second fiber layer. The first fiber layer was 10 μm thick.

[0214] At this time, the vascular stent forms a three-layer composite structure consisting of a first fiber layer, a second fiber layer and a first fiber layer from the inside to the outside, and the total thickness of the vascular stent is 100 μm.

[0215] S2: Press Grip

[0216] The stent is pressed onto the balloon to meet the dimensions required for delivery within the human body. During the pressing process, the stent is placed in a pressing medium to ensure the mechanical properties of the stent.

[0217] The following parameters are used for crimping: the crimping medium is a mixed solution of ethanol and ethylene glycol with a volume ratio of 7 to 3, the crimping rate is 0.02-0.12 mm / s, the crimping medium temperature is 45-55°C, the holding time is 30s, and the holding temperature is 45-55°C.

[0218] Example 3 Comparative Example 4:

[0219] S1: Preparation of fiber aggregate-shaped vascular scaffolds

[0220] PLGA8218 (molecular weight 200,000-300,000) was dissolved in hexafluoroisopropanol to prepare a first solution with a mass fraction of 4-6%. Hyaluronic acid (molecular weight 30,000-45,000) was dissolved in water to prepare a second solution with a mass fraction of 2-5%. Electrospinning was performed using an electrospinning device using the following parameters: 18G / 14G coaxial electrospinning nozzles, a spinning voltage of 20-22 kV, a shell injection speed of 0.10-0.15 mm / min, a core injection speed of 0.05-0.15 mm / min, a receiving distance of 60-80 mm, an ambient temperature of 25±1°C, and an ambient humidity of 45±5%. The receiving device had an outer diameter of 2.5 mm and a rotation speed of 4500-5000 rpm. A first fiber layer with a thickness of 10 μm was deposited on the receiving device.

[0221] PLGA8218 (molecular weight 200,000-300,000) was dissolved in hexafluoroisopropanol to prepare a 4-6% solution. Electrospinning was performed using an 18G electrospinning nozzle, a spinning voltage of 20-22 kV, an injection speed of 0.05-0.15 mm / min, a receiving distance of 60-80 mm, an ambient temperature of 25 ± 1°C, and an ambient humidity of 45 ± 5%. The receiving device had an outer diameter of 2.5 mm and a rotation speed of 4500-5000 rpm. A second fiber layer was deposited on the receiving device, attached to the first fiber layer, with a thickness of 80 μm.

[0222] PLGA8218 (molecular weight 200,000-300,000) was dissolved in hexafluoroisopropanol to prepare a first solution with a mass fraction of 4-6%. Hyaluronic acid (molecular weight 30,000-45,000) was dissolved in water to prepare a second solution with a mass fraction of 2-5%. Electrospinning was performed using an electrospinning device using the following parameters: 18G / 14G coaxial electrospinning nozzles, a spinning voltage of 20-22 kV, a shell injection speed of 0.10-0.15 mm / min, a core injection speed of 0.05-0.15 mm / min, a receiving distance of 60-80 mm, an ambient temperature of 25±1°C, and an ambient humidity of 45±5%. The outer diameter of the receiving device was 2.5 mm, and the receiving device rotation speed was 4500-5000 rpm. The first fiber layer was then deposited on the receiving device, attached to the second fiber layer. The first fiber layer was 10 μm thick.

[0223] At this time, the vascular stent forms a three-layer composite structure consisting of a first fiber layer, a second fiber layer and a first fiber layer from the inside to the outside, and the total thickness of the vascular stent is 100 μm.

[0224] S2: Heat treatment

[0225] The stent is placed on the heat treatment liner and placed in the air, and the heat treatment medium is heated, kept warm, and cooled. The heating, keeping warm, and cooling cycles can be repeated multiple times.

[0226] The heat treatment was performed using the following parameters: a 2.5 mm outer diameter core, an initial temperature of 19-22°C, a heating rate of 2.0-2.5°C / min, a holding time of 5-10 min, a cooling rate of 7-8°C / min, and a final temperature of 19-22°C. The number of cycles was 2.

[0227] In the above implementation, it is divided into three groups, among which Example 1, Example 1 Control Example 1, Example 1 Control Example 2, Example 1 Control Example 3 and Example 1 Control Example 4 are one group; Example 2, Example 2 Control Example 1, Example 2 Control Example 2, Example 2 Control Example 3 and Example 2 Control Example 4 are one group; Example 3, Example 3 Control Example 1, Example 3 Control Example 2, Example 3 Control Example 3 and Example 3 Control Example 4 are one group.

[0228] In addition, the vascular stents in Example 1, Example 2, and Example 3 all use solid fiber filaments and are made of only degradable and water-insoluble polymers. The above three examples are existing vascular stents and serve as control groups.

[0229] Please refer to Figure 1. The vascular stent prepared in the above embodiment was expanded using balloons with different outer diameters, including 2.50, 2.75, 3.00, 3.25, 3.50, 3.75 and 4.00 mm. The expansion and fracture of the vascular stent were observed. At the same time, the radial support force of the successfully expanded vascular stent was tested with reference to standard YY / T 0663.2-2016.

[0230] As can be seen from the data in FIG1 , the supporting force of the coaxially electrospun vascular stent is substantially the same as that of the conventional electrospun vascular stent (Comparative Example 1 of Example 1, Comparative Example 1 of Example 2, and Comparative Example 1 of Example 3);

[0231] Conventional electrospun vascular stents (Example 1, Example 1, Example 2, and Example 3) experience varying degrees of fracture during expansion. The coaxially electrospun vascular stent exhibits far superior expansion performance to conventional electrospun vascular stents, while maintaining radial support within a certain range, allowing surgeons greater flexibility in selecting stent specifications during surgery. The heat treatment process significantly impacts stent support performance.

[0232] The above description is only a description of the preferred embodiments of the present invention and is not intended to limit the scope of the present invention. Any changes and modifications made by ordinary technicians in the field of the present invention based on the above disclosure shall fall within the scope of protection of the claims.

Claims

1. A method for preparing a vascular stent, characterized in that, Comprising: Dissolve a degradable water-insoluble polymer in a solvent to prepare a first spinning solution, and dissolve a degradable water-soluble polymer in a solvent to prepare a second spinning solution; Feed the first spinning solution and the second spinning solution into an electrospinning device to perform electrospinning to form a vascular stent.

2. The method for preparing a vascular stent according to claim 1, wherein During the process of simultaneously feeding the first spinning solution and the second spinning solution into the electrospinning device to perform electrospinning, coaxial fiber filaments are generated, and the coaxial fiber filaments are intertwined to form at least a part of the vascular stent; The coaxial fiber filaments include a core layer and a shell layer, the shell layer wraps the core layer, the core layer is generated by the first spinning solution, and the shell layer is generated by the second spinning solution.

3. The method for preparing a vascular stent according to claim 2, wherein, During the process of separately feeding the first spinning solution into the electrospinning device to perform electrospinning, solid fiber filaments are generated, and the solid fiber filaments are intertwined to form at least a part of the vascular stent.

4. The method for preparing a vascular stent according to claim 3, wherein The coaxial fiber filaments are intertwined to form a first fiber layer, the solid fiber filaments are intertwined to form a second fiber layer, and the first fiber layer and the second fiber layer are stacked to form the vascular stent.

5. The method for preparing a vascular stent according to claim 4, wherein, The percentage of the thickness of the first fiber layer in the total thickness of the vascular stent is 60%-80%.

6. The method for preparing a vascular stent according to claim 4, wherein The first fiber layer is one layer or multiple layers, the second fiber layer is one layer or multiple layers, and the first fiber layer and the second fiber layer are arranged alternately.

7. The method for preparing a vascular stent according to claim 1, characterized in that, The degradable water-insoluble polymer includes one or a mixture and / or copolymer of two or more of polylactide, polyglycolide, polycaprolactone, poly-p-dioxanone, polytrimethylene carbonate, polyester amide, polyhydroxyalkanoate, polyurethane, and poly(lactide-co-glycolide).

8. The method for preparing a vascular stent according to claim 1, characterized in that, The degradable water-soluble polymer includes one or a mixture and / or copolymer of two or more of polyvinyl alcohol, polyethylene glycol, polyethylene oxide, polyvinylpyrrolidone, polyethyleneimine, hyaluronic acid, gelatin, collagen, sodium alginate, and hyaluronic acid.

9. The method for preparing a vascular stent according to claim 1, characterized in that, The solvent includes at least one of water, hexafluoroisopropanol, dichloromethane, chloroform, tetrahydrofuran, N,N-dimethylformamide, dimethyl sulfoxide, acetone, n-propyl acetate, and n-butyl acetate.

10. The method for preparing a vascular stent according to claim 1, wherein, The method for preparing the vascular stent further includes: Performing heat treatment on the prepared vascular stent; The heat treatment includes: Placing the vascular stent in a heat treatment medium, and heating, maintaining the temperature, and cooling the heat treatment medium.

11. The method for preparing a vascular stent according to claim 10, wherein, The heat treatment medium includes one or a mixture of two or more of air, ethanol, ethylene glycol, and glycerol.

12. A method for preparing a vascular stent system, characterized in that Comprising: Selecting a vascular stent prepared by the method for preparing a vascular stent according to any one of claims 1 to 11; Selecting a balloon, and sleeving the vascular stent outside the balloon; Placing the vascular stent in a crimping medium for crimping to crimp the vascular stent onto the balloon.

13. The method for preparing a vascular stent system according to claim 12, characterized in that, The crimping medium includes one or a mixture of two or more of air, ethanol, ethylene glycol, and glycerol.

14. A vascular stent, characterized in that, Comprising a stent body, the stent body includes a superimposed first fiber layer and a second fiber layer; The first fiber layer is formed by the interweaving of coaxial fiber filaments. The coaxial fiber filaments include a core layer and a shell layer. The core layer is made of a degradable non-water-soluble polymer, and the shell layer is made of a degradable water-soluble polymer. The shell layer wraps around the core layer; The second fiber layer is formed by the interweaving of solid fiber filaments. The solid fiber filaments are made of a degradable non-water-soluble polymer.

15. A vascular stent system, characterized in that, Comprising: The vascular stent and balloon according to claim 14, wherein the vascular stent is sleeved outside the balloon and crimped on the balloon.

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