Double-layer hot-melt stent, manufacturing method and double-layer hot-melt stent release device

Abstract

The invention provides a double-layer hot-melt stent, a manufacturing method thereof and a double-layer hot-melt stent release device. The double-layer hot-melt stent comprises a frame, a porous fiber membrane and a drug coating. The frame is in a hollow cylinder shape and comprises an inner layer frame and an outer layer frame, the inner layer frame is located in the outer layer frame and forms a net-shaped structure with the outer layer frame, the contact positions of the inner layer frame and the outer layer frame are connected in a hot melting mode, and the frame is made of biodegradable materials. The porous fiber membrane is arranged on the surface of the frame, the porosity of the porous fiber membrane is larger than 70%, and the porous fiber membrane is made of biodegradable materials. The drug coating is distributed in pores of the porous fiber membrane and can prevent cells and tissues from being adhered and proliferated on the surface of the stent.

Description

Technical Field

[0001] The present application relates to the technical field of medical devices, and in particular to a double-layer hot-melt stent, a manufacturing method thereof, and a double-layer hot-melt stent releasing device. Background Art

[0002] Tubal infertility is one of the main causes of female infertility, among which obstruction or stenosis of the interstitial part of the fallopian tube is more common. Traditional treatment methods often use fallopian tube stent implantation, but the stents in the prior art have many defects: traditional fallopian tube stents are mostly made of metal or non-degradable polymers, which will remain in the human body for a long time, acting as foreign bodies to continuously stimulate the fallopian tube tissue, leading to inflammatory reactions, thereby increasing the risk of postoperative restenosis, seriously affecting the treatment effect and patient health. In addition, the stent surface lacks an effective anti-adhesion coating, and the fallopian tube tissue is prone to proliferate on the stent surface after surgery, resulting in secondary blockage of the lumen, which reduces the success rate of fallopian tube stent implantation. In addition, the stents in the prior art are usually only a single-layer structure, with insufficient stent strength and radial support force, which further makes it easy for postoperative restenosis and secondary blockage to occur. Summary of the Invention

[0003] The main purpose of the present application is to provide a degradable, anti-adhesion, high-strength double-layer hot-melt stent and a manufacturing method thereof.

[0004] Another main purpose of the present application is to provide a double-layer hot-melt stent release device to avoid the stent locking phenomenon during release.

[0005] To achieve the above objectives, this application adopts the following technical solutions:

[0006] According to one aspect of the present application, a double-layer hot-melt stent is provided, comprising a frame, a porous fiber membrane and a drug coating. The frame comprises a cylindrical inner frame and a cylindrical outer frame, the inner frame being located within the outer frame and in contact with the outer frame to form a mesh structure together, the inner frame being connected by heat-melting at the position where it contacts the outer frame, and the frame is made of a biodegradable material. A porous fiber membrane is provided on the surface of the frame, the porosity of the porous fiber membrane being greater than 70%, and the material of the porous fiber membrane is a biodegradable material. The drug coating is distributed in the pores of the porous fiber membrane and can prevent cells and tissues from adhering to and proliferating on the surface of the stent.

[0007] According to one embodiment of the present application, the inner frame and the outer frame are wound by the same wire, and the wire is first wound to form one of the inner frame and the outer frame, and then wound to form the other one.

[0008] According to one embodiment of the present application, the inner layer frame includes a plurality of inner layer threads parallel to each other, and the inner layer threads are inclined in a first direction relative to the central axis of the inner layer frame; the outer layer frame includes a plurality of outer layer threads parallel to each other, and the outer layer threads are inclined in a second direction relative to the central axis of the outer layer frame, and the second direction is opposite to the first direction.

[0009] According to one embodiment of the present application, the material of the frame includes poly(lactic acid-co-glycolic acid) copolymer and nano-hydroxyapatite.

[0010] According to one embodiment of the present application, the pore size of the porous fiber membrane is 280nm-350nm.

[0011] According to another aspect of the present application, the present application also provides one or more methods for manufacturing a double-layer hot-melt stent, comprising the following steps: Step S1: making the frame; Step S2: forming the porous fiber membrane on the surface of the frame; Step S3: preparing a solution of the drug coating, and impregnating the drug coating into the pores of the porous fiber membrane by vacuum impregnation.

[0012] According to one embodiment of the present application, step S1 includes: step S11: using biodegradable material to make silk thread; step S12: on the woven tooling, first winding the silk thread to form one of the inner layer frame and the outer layer frame, and then winding it to form the other one, to obtain the frame intermediate structure; step S13: assembling the frame intermediate structure into a heat shrink tube, heating it, so that the contact position of the inner layer frame and the outer layer frame is welded and connected to form the frame.

[0013] According to one embodiment of the present application, step S12 includes: on the weaving tool, winding the wire circumferentially at an angle inclined in a first direction relative to the central axis of the inner frame to form the inner frame, and then winding the wire circumferentially at an angle inclined in a second direction relative to the central axis of the outer frame to form the outer frame, wherein the second direction is opposite to the first direction.

[0014] According to one embodiment of the present application, the diameter of the wire is 180um-220um.

[0015] According to one embodiment of the present application, step S2 includes: step S21: preparing a biodegradable material solution; step S22: assembling the frame onto an electrospinning device, and weaving the porous fiber membrane on the surface of the frame.

[0016] According to one embodiment of the present application, step S3 includes: step S31: uniformly mixing rapamycin and hyaluronic acid to form a solution of the drug coating; step S32: impregnating the drug coating into the pores of the porous fiber membrane using a vacuum impregnation method, and performing freeze-drying treatment.

[0017] According to one embodiment of the present application, the freeze-drying process includes multiple processing steps with different temperatures.

[0018] According to another aspect of the present application, a double-layer hot-melt stent release device is provided, comprising the double-layer hot-melt stent described above and a catheter. The catheter comprises an inner tube and an outer tube, the double-layer hot-melt stent being disposed within the inner tube, and the outer tube driving the inner tube to release the double-layer hot-melt stent. The inner tube has a groove disposed on its wall corresponding to the double-layer hot-melt stent, the groove being disposed axially along the inner tube.

[0019] According to one embodiment of the present application, the length of the slot along the axial direction of the inner tube is 5 mm to 50 mm, and the width of the slot is 0.1 mm to 1 mm.

[0020] According to one embodiment of the present application, a groove is provided on the tube wall of the end portion of the inner tube and is connected to the end surface corresponding to the end portion of the inner tube.

[0021] According to one embodiment of the present application, the outer tube includes a first section and a second section, the inner diameter of the first section is smaller than the inner diameter of the second section, a limiting portion is provided at one end of the inner tube, the maximum size of the limiting portion is larger than the inner diameter of the first section and smaller than the inner diameter of the second section, and the outer tube drives the inner tube to move through the limiting portion.

[0022] From the above technical solution, it can be seen that the advantages and positive effects of the double-layer hot-melt bracket proposed in this application are:

[0023] The double-layer hot-melt stent proposed in this application has a double-layer frame, in which the inner frame and the outer frame form a mesh structure, which can improve the strength of the stent, increase the radial support force of the stent, and avoid postoperative restenosis and secondary blockage.

[0024] The double-layer hot-melt stent proposed in this application has a porous fiber membrane on the surface of the stent, and the drug coating is set in the pores of the porous fiber membrane, which can prevent adhesion and avoid postoperative proliferation of fallopian tube tissue on the surface of the stent, resulting in secondary blockage of the lumen.

[0025] The double-layer hot-melt stent proposed in this application has a frame and a porous fiber membrane made of biodegradable materials. The stent can be degraded in the human body, avoiding long-term stimulation of the fallopian tube tissue by the stent and avoiding the occurrence of inflammatory response. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The various objects, features, and advantages of the present application will become more apparent by considering the following detailed description of the preferred embodiments of the present application in conjunction with the accompanying drawings. The accompanying drawings are merely illustrative illustrations of the present application and are not necessarily drawn to scale. In the drawings, the same reference numerals always indicate the same or similar parts.

[0027] Figure 1 It is a structural schematic diagram of the double-layer hot-melt bracket of the present application.

[0028] Figure 2 yes Figure 1 Top view of .

[0029] Figure 3 yes Figure 2 Schematic diagram of the enlarged position I.

[0030] Figure 4 yes Figure 3 Schematic diagram of removing the drug coating.

[0031] Figure 5 The figure shows the wire winding state of the double-layer hot-melt stent of the present application.

[0032] Figure 6 yes Figure 5 Top view of .

[0033] Figure 7 It is a schematic diagram of the intermediate structure of the frame obtained after the wire winding of the double-layer hot-melt stent of the present application is completed.

[0034] Figure 8 yes Figure 7 Top view of .

[0035] Figure 9 yes Figure 8 Enlarged view of point II in the middle.

[0036] Figure 10 It is a schematic diagram of a frame obtained after the middle structure of the frame of the double-layer hot-melt bracket of the present application is hot-melted.

[0037] Figure 11 yes Figure 10 Top view of .

[0038] Figure 12 yes Figure 11 Magnified view of III.

[0039] Figure 13 It is a schematic structural diagram of the inner tube of the double-layer hot-melt stent release device of the present application.

[0040] Figure 14 yes Figure 13 AA section view.

[0041] Figure 15 It is a schematic structural diagram of the outer tube of the double-layer hot-melt stent release device of the present application.

[0042] Figures 16 to 18 It is a schematic diagram of the loading process of the double-layer hot-melt stent of the present application.

[0043] Figures 19 to 21 It is a schematic diagram of the release process of the double-layer hot-melt stent of the present application.

[0044] The following are the descriptions of the reference numerals:

[0045] 1-Double-layer hot-melt bracket;

[0046] 2-catheter;

[0047] 3-Balloon;

[0048] 4-Luer connector;

[0049] 5-Guidewire;

[0050] 6-development ring;

[0051] 10-frame;

[0052] 11-woven workwear;

[0053] 12-silk thread;

[0054] 13- convex;

[0055] 20-porous fiber membrane;

[0056] 21- inner tube;

[0057] 22-outer tube;

[0058] 30-drug coating;

[0059] 100-through hole;

[0060] 101-Inner frame;

[0061] 102- outer frame;

[0062] 211-slotting;

[0063] 212-Limiting part

[0064] 221- first paragraph;

[0065] 222-Second paragraph;

[0066] D1-first direction;

[0067] D2 - Second direction. DETAILED DESCRIPTION

[0068] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the concepts of the example embodiments to those skilled in the art. Like reference numerals in the figures represent like or similar structures, and thus their detailed description will be omitted.

[0069] In the following description of different exemplary embodiments of the present application, reference is made to the accompanying drawings, which form a part of the present application and in which different exemplary structures, systems and steps that can implement various aspects of the present application are shown by way of example. It should be understood that other specific schemes of components, structures, exemplary devices, systems and steps can be used, and structural and functional modifications can be made without departing from the scope of the present application. Moreover, although the terms "above", "between", "within", etc. may be used in this specification to describe different exemplary features and elements of the present application, these terms are used herein for convenience only, for example, according to the directions of the examples described in the accompanying drawings. Nothing in this specification should be construed as requiring a specific three-dimensional orientation of the structure to fall within the scope of the present application.

[0070] It is understood that the terms "including" and "having" and any variations thereof in the embodiments of the present application are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or components inherent to the process, method, product, or apparatus.

[0071] Relative terms such as "lower" or "bottom" and "upper" or "top" may be used herein to describe the relationship of one element to another element, as shown in the figures. It should be understood that relative terms are intended to include different orientations of the device in addition to the orientation shown in the figures. For example, if the device in a figure is turned over, the element described as being "lower" or "bottom" of other elements will be oriented "upper" or "top" of the other elements. Thus, the exemplary term "lower" can include both "lower" and "top" orientations, and the term "bottom" can include both "bottom" and "top" orientations, depending on the particular orientation of the figure. Similarly, if the device in a figure is turned over, the element described as being "lower" or "bottom" of other elements will be oriented as being "upper" or "top" of the other elements. Thus, the exemplary terms "bottom" or "below" can include both "upper" and "lower" orientations.

[0072] See Figures 1 to 4The double-layer hot-melt stent 1 of the present application comprises a frame 10, a porous fiber membrane 20 and a drug coating 30. The frame 10 is in the shape of a hollow cylinder with a through hole 100 formed in the center. The frame 10 comprises a cylindrical inner frame 101 and an outer frame 102. The inner frame 101 is located within the outer frame 102 and contacts the outer frame 102 to form a cross-net structure. The position where the inner frame 101 contacts the outer frame 102 is hot-melt-connected. The material of the frame 10 is a biodegradable material. The porous fiber membrane 20 is arranged on the surface of the frame 10. The porosity of the porous fiber membrane 20 is greater than 70%. The material of the porous fiber membrane 20 is a biodegradable material. The drug coating 30 is distributed in the pores of the porous fiber membrane 20 and can prevent cells and tissues from adhering to and proliferating on the surface of the stent 1.

[0073] The double-layer hot-melt stent 1 of the present application has a double-layer structure in which the frame 10 is formed with an inner frame 101 and an outer frame 102 forming a cross-mesh structure, which can improve the strength of the stent and increase the radial support force of the stent. The hot-melt connection makes the connection between the inner frame 101 and the outer frame 102 more secure, further enhancing the strength of the frame 10. A porous fiber membrane 20 is provided on the surface of the stent, and a drug coating 30 is provided in the pores of the porous fiber membrane 20, which can prevent adhesion and avoid postoperative proliferation of fallopian tube tissue on the surface of the stent 1, resulting in secondary blockage of the lumen of the fallopian tube.

[0074] The double-layer hot-melt stent 1, frame 10 and porous fiber membrane 20 proposed in this application are all made of biodegradable materials. The stent 1 can be degraded in the human body, avoiding long-term stimulation of the stent 1 to the fallopian tube tissue and the occurrence of inflammatory response.

[0075] In this embodiment, the frame 10 is made of polylactic-co-glycolic acid (PLGA) and nanohydroxyapatite (HA); the ratio of lactic acid (LA) to glycolic acid (GA) is LA:GA = 75:25, or alternatively, LA:GA = 70:30 or LA:GA = 80:20. This ratio controls the degradation rate of the stent 1, allowing it to gradually degrade into harmless substances and be absorbed by the human body within 3-6 months. Furthermore, nanohydroxyapatite particles are uniformly mixed into the PLGA at a mass fraction of 3%-8%, which enhances the biological activity of the stent 1 and promotes fallopian tube tissue repair. In this embodiment, the mass fraction of the nanohydroxyapatite particles is 5%.

[0076] In this embodiment, the pore size of the porous fiber membrane 20 is 280 nm to 350 nm, so as to provide sufficient space for the drug coating 30. The pore size can be specifically 300 nm, 320 nm, 330 nm, 340 nm, etc.

[0077] See also Figures 5 to 9In this embodiment, the double-layer hot-melt bracket 1 of the present application, the inner layer frame 101 and the outer layer frame 102 are wound by the same wire 12, and the wire 12 is first wound to form the inner layer frame 101, and then wound to form the outer layer frame 102. In some other embodiments, the outer layer frame 102 can be wound first, and then wound to form the inner layer frame 101. The inner layer frame 101 includes a plurality of inner layer wires parallel to each other, and the inner layer wires are inclined in a first direction D1 relative to the central axis of the inner layer frame 101; the outer layer frame 102 includes a plurality of outer layer wires parallel to each other, and the outer layer wires are inclined in a second direction D2 relative to the central axis of the outer layer frame 102, and the second direction D2 is opposite to the first direction D1. The central axis of the inner layer frame 101 and the central axis of the outer layer frame 102 are on a straight line.

[0078] Among them, the material of the silk thread 12 is the material of the frame 10. In this embodiment, the material of the silk thread 12 is made of polylactic acid-glycolic acid copolymer (PLGA) as the main material, and nano-hydroxyapatite (HA) particles with a mass fraction of 5% are evenly mixed into the PLGA to form a mixed copolymer. The above mixed copolymer is made into a silk thread 12 with a diameter of 180um-220um by extrusion. Specifically, a silk thread 12 with a diameter of 200um can be used, a silk thread 12 with a diameter of 190um can be used, and a silk thread 12 with a diameter of 210um can be used. This can enhance the biological activity of the stent 1, promote the repair of fallopian tube tissue, and enable the stent 1 to gradually degrade into harmless substances and be absorbed by the human body within 3-6 months. The double-layer grid setting can improve the strength of the stent, enhance the radial support force of the stent, and reduce the risk of postoperative restenosis and secondary blockage.

[0079] See Figures 1 to 12 The manufacturing method of the double-layer hot-melt stent 1 of the present application includes the following steps: Step S1: making a frame 10; Step S2: forming a porous fiber membrane 20 on the surface of the frame 10; Step S3: preparing a solution of the drug coating 30, and impregnating the drug coating 30 into the pores of the porous fiber membrane 20 by vacuum impregnation.

[0080] The manufacturing method of the double-layer hot-melt stent 1 of the present application uses biodegradable materials to make the frame 10 and the porous fiber membrane 20. The stent 1 can be degraded in the human body, avoiding long-term stimulation of the stent 1 to the fallopian tube tissue and avoiding the occurrence of inflammatory response; the drug coating 30 is impregnated in the pores of the porous fiber membrane 20. The method is simple and has a good impregnation effect. It can prevent adhesion and avoid postoperative proliferation of fallopian tube tissue on the surface of the stent 1, which leads to secondary blockage of the lumen.

[0081] In this embodiment, see Figures 5 to 12Step S1 includes: Step S11: Using biodegradable materials to make silk thread 12; in this embodiment, silk thread 12 uses polylactic acid-glycolic acid copolymer (PLGA) as the main material, and nano-hydroxyapatite (HA) particles with a mass fraction of 5% are evenly mixed into PLGA to form a mixed copolymer, which is then extruded. It can enhance the biological activity of the stent 1, promote the repair of fallopian tube tissue, and enable the stent 1 to gradually degrade into harmless substances and be absorbed by the human body within 3-6 months. Step S12: On the braided tooling, first wind the silk thread 12 to form one of the inner layer frame 101 and the outer layer frame 102, and then wind it to form the other one, to obtain the intermediate structure of the frame.

[0082] In this embodiment, see Figures 5 to 9 On the braiding tool 11, the inner frame 101 is formed by winding the wire 12 along the circumference at an angle inclined in a first direction D1 relative to the central axis of the inner frame 101. Then, the outer frame 102 is formed by winding the wire 12 along the circumference at an angle inclined in a second direction D2 relative to the central axis of the outer frame 102. The second direction D2 is opposite to the first direction D1, forming a cross-net structure. The inclination angle of the inner frame 101 and the inclination angle of the outer frame 102 can be the same or different. The specific braiding process is as follows:

[0083] First, a gap of 0.3-0.8mm is formed on the braided tooling 11. In this embodiment, a gap of 0.5mm is used. A circle of silk thread 12 is wound along the circumference at an angle of 20 degrees relative to the central axis of the inner frame 101 in the first direction D1 to form the inner frame 101. The winding can be done in a clockwise direction or a counterclockwise direction. The braided tooling 11 is provided with a plurality of protrusions 13 for winding. Then, a second circle of silk thread 12 is wound along the circumference at an angle of 20 degrees relative to the central axis of the outer frame 102 in the second direction D2 to form the outer frame 102. After that, a double-layer cross-mesh structure formed by winding a single silk thread 12 is obtained to obtain the middle structure of the frame. The double-layer grid setting can improve the strength of the stent 1, enhance the radial support force of the stent 1, and reduce the risk of postoperative restenosis and secondary blockage.

[0084] In this embodiment, step S1 further includes: step S13: after assembling the intermediate frame structure into a heat shrink tube, heating is performed to weld the inner frame 101 and the outer frame 102 at the contact position to form the frame 10. In this embodiment, the intermediate frame structure is coaxially assembled into a fluorinated ethylene propylene (FEP) easy-tear heat shrink tube, placed in a constant temperature oven, and the temperature in the oven is increased in multiple stages to form the frame 10.

[0085] In this embodiment, the temperature in the oven is increased in three stages, and the temperature increase process is shown in Table 1 below:

[0086] Table 1: Temperature stages of heat melting of frame 10

[0087] stage Temperature setting (℃) Residence time (min) Phase 1 35-40 3-8 Phase II 60-80 12-20 Phase 3 150-200 3-8

[0088] In this embodiment, the first stage is 37.5°, maintained for 5 minutes; then the temperature is raised to 68° to enter the second stage and maintained for 15 minutes; then the temperature is raised to 160° and maintained for 5 minutes. Since the general melting temperature of PLGA is around 196°, when the middle structure of the frame is heated to a certain temperature in the oven (such as 150-260°C), the FEP heat shrink tube begins to generate an inward shrinkage force. At this time, when the temperature reaches near the melting temperature of PLGA, the contact positions of the inner frame 101 and the outer frame 102 of the frame 10 are simultaneously welded together by the inward radial force of the heat shrink tube. The multi-stage heating mode can ensure that when the contact positions of the inner frame 101 and the outer frame 102 of the frame 10 are welded, the inward radial force of the heat shrink tube is uniform, thereby making the elastic modulus of the frame 10 higher.

[0089] In this embodiment, step S2 includes: step S21: preparing a biodegradable material solution; in this embodiment, polylactic acid-co-caprolactone polymer (PLCL) is used, wherein the ratio of lactic acid (LA) to caprolactone CL is 70:30, and the molecular weight (Mn = 50-80 kDa). The PLCL concentration is 5% w / v (i.e., 5 g of 20 kDa PLCL is dissolved in 100 mL of hexafluoroisopropanol (HFIP)), and magnetic stirring is performed for 24-48 hours until completely dissolved, forming a PLCL homogeneous solution at 25° C. with a viscosity of approximately 50-100 mPa·s, thereby preparing the biodegradable material solution.

[0090] In this embodiment, step S2 further includes: step S22: assembling the frame 10 onto an electrospinning device, and weaving a porous fiber membrane 20 on the surface of the frame 10. In this embodiment, the frame 10 is assembled onto a carrier of a high-voltage electrospinning machine, and the PLCL homogeneous solution is spun onto the frame 10, wherein the weaving parameters are shown in Table 2 below:

[0091] Table 2: Textile parameters

[0092]

[0093] After high-voltage electrospinning, a porous fiber membrane 20 with a pore size of about 280-350 nm and a porosity greater than 70% is obtained on the surface of the frame 10 .

[0094] In this embodiment, step S3 includes: step S31: uniformly mixing rapamycin and hyaluronic acid to form a solution of the drug coating 30; wherein the preparation process of the solution of the drug coating 30 is as follows:

[0095] First, dissolve rapamycin. Add rapamycin powder to ethanol and ultrasonically vibrate for 20-50 minutes until completely dissolved (if the solubility is insufficient, the ethanol ratio can be appropriately increased to 5:5 v / v). At the same time, dissolve hyaluronic acid (HA). Slowly sprinkle the hyaluronic acid powder into deionized water and stir at a low speed (≤200 rpm) until it is completely swollen (avoid high-speed shearing to destroy the molecular chain) to form a transparent colloid. Then mix and homogenize. Slowly pour the rapamycin ethanol solution into the hyaluronic acid aqueous solution while stirring. Add a surfactant, which can be Tween-80 in this embodiment, or other types of surfactants in other embodiments. Continue stirring for 1-1.5 hours until uniform. Among them, the surfactant Tween-80 can also be omitted. If adhesion needs to be enhanced, a chitosan solution of adhesive can be added at this stage (wherein chitosan needs to be pre-dissolved in 1% acetic acid aqueous solution to form a chitosan solution). The composition of the solution of the prepared drug coating 30 is shown in Table 3 below:

[0096] Table 3: Solution composition of drug coating 30

[0097] Rapamycin 0.65 mg / mL Hyaluronic acid (HA) 1~5% (w / v) Solvent system Ethanol-water (3:7 v / v) surfactants Tween-80 (0.1%) adhesives Chitosan (0.5-1%)

[0098] In this embodiment, step S3 includes: step S32: using a vacuum impregnation method to impregnate the drug coating 30 into the pores of the porous fiber membrane 20, wherein the vacuum impregnation process is to place the frame 10 with the porous fiber membrane 20 on the surface in a container of a solution (impregnation liquid) of the drug coating 30, connect the container and the vacuum equipment, and perform a vacuum treatment. After the vacuum is completed, the frame 10 with the porous fiber membrane 20 on the surface is allowed to soak in the solution (impregnation liquid) of the drug coating 30 for a period of time, so that the drug coating 30 is impregnated in the pores of the porous fiber membrane 20. Thereafter, the bracket 1 is taken out and freeze-dried. Among them, the freeze-drying treatment includes multiple treatment processes with different temperatures. The parameters of the vacuum impregnation and freeze-drying processes are shown in Table 4 below:

[0099] Table 4: Parameters of vacuum impregnation and freeze-drying

[0100]

[0101] The vacuum impregnation can make the drug coating 30 fully fill the pores of the porous fiber membrane 20, and the freeze-drying treatment using different freeze-drying temperatures can prevent cracks from appearing in the drug coating 30 during freeze-drying.

[0102] The above is a first embodiment of the method for manufacturing a double-layer hot-melt stent 1 of the present application. The second embodiment of the method for manufacturing a double-layer hot-melt stent 1 is described below. The second embodiment has the same steps as the first embodiment, differing only in the parameters in step S21 of step S2. In the second embodiment, step S21: preparing a biodegradable material solution. In this embodiment, polylactic acid-co-caprolactone polymer (PLCL) is used, wherein the ratio of lactic acid (LA) to caprolactone CL is 75:25, and the molecular weight (Mn) is 50-80 kDa. A PLCL concentration of 5% w / v (i.e., 5 g of 20 kDa PLCL is dissolved in 100 mL of hexafluoroisopropanol (HFIP)) is magnetically stirred for 24-48 hours until completely dissolved, forming a homogeneous PLCL solution with a viscosity of approximately 50-100 mPa·s at 25°C, thereby preparing a biodegradable material solution.

[0103] The manufacturing method of the double-layer hot-melt stent 1 of the present application also has a third embodiment, wherein the steps of the third embodiment are the same as those of the first embodiment, and the only difference is that the weaving parameters in step S22 of step S2 are different. In the third embodiment, the weaving parameters are shown in Table 5 below:

[0104] Table 5: Textile parameters in the third embodiment

[0105]

[0106]

[0107] The manufacturing method of the double-layer hot-melt stent 1 of the present application also has a fourth embodiment, wherein the steps of the fourth embodiment are the same as those of the first embodiment, and the only difference is that the parameters of the vacuum impregnation and freeze-drying process in step S32 of step S3 are different. In the fourth embodiment, the parameters of the vacuum impregnation and freeze-drying process are shown in Table 6 below:

[0108] Table 6: Parameters of vacuum impregnation and freeze-drying

[0109]

[0110] The manufacturing method of the double-layer hot-melt stent 1 of the present application also has a fifth embodiment, wherein the steps of the fifth embodiment are the same as those of the first embodiment, and the only difference is that the specific weaving parameters of step S12 in step S1 are different. In the fifth embodiment, a circle of silk thread 12 is wound around the circumference of the braided tool 11 at a gap of 0.4 mm at an angle of 30 degrees relative to the central axis of the inner frame 101 in the first direction D1 to form the inner frame 101. The winding can be done in a clockwise direction or a counterclockwise direction. The braided tool 11 is provided with a plurality of protrusions 13 for winding. Then, a second circle of silk thread 12 is wound around the circumference at an angle of 30 degrees relative to the central axis of the outer frame 102 in the second direction D2 to form the outer frame 102; and then a double-layer cross-mesh structure formed by winding a single silk thread 12 is obtained, thereby obtaining the intermediate structure of the frame.

[0111] The manufacturing method of the double-layer hot-melt stent 1 of the present application also has a sixth embodiment, wherein the steps of the sixth embodiment are the same as those of the first embodiment, and the only difference is that the specific weaving parameters of step S12 in step S1 are different. In the sixth embodiment, a circle of silk thread 12 is wound around the inner frame 101 at an angle of 20 degrees relative to the central axis of the inner frame 101 along the circumference with a gap of 0.6 mm, to form the inner frame 101. The winding can be done in a clockwise direction or a counterclockwise direction. The weaving tool 11 is provided with a plurality of protrusions 13 for winding. Then, a second circle of silk thread 12 is wound around the circumference at an angle of 30 degrees relative to the central axis of the outer frame 102 in the second direction D2; the outer frame 102 is formed; and then a double-layer cross-mesh structure formed by winding a single silk thread 12 is obtained, thereby obtaining the intermediate structure of the frame.

[0112] The manufacturing method of the double-layer hot-melt stent 1 of the present application also has a seventh embodiment, wherein the steps of the seventh embodiment are the same as those of the first embodiment, and the only difference is that the specific weaving parameters of step S12 in step S1 are different. In the seventh embodiment, a circle of silk thread 12 is wound around the inner frame 101 at an angle of 25 degrees relative to the central axis of the inner frame 101 along the circumference with a gap of 0.7 mm, to form the inner frame 101. The winding can be done in a clockwise direction or a counterclockwise direction. The weaving tool 11 is provided with multiple protrusions 13 for winding. Then, a second circle of silk thread 12 is wound around the circumference at an angle of 35 degrees relative to the central axis of the outer frame 102 in the second direction D2; the outer frame 102 is formed; and then a double-layer cross-mesh structure formed by winding a single silk thread 12 is obtained, resulting in the intermediate structure of the frame.

[0113] like Figures 13 to 21As shown, the stent 1 of the present application is used in conjunction with the catheter 2 to form a double-layer hot-melt stent release device, which includes the double-layer hot-melt stent 1 and the catheter 2. The catheter 2 includes an inner tube 21 and an outer tube 22. The double-layer hot-melt stent 1 is arranged in the inner tube 21, and the outer tube 22 drives the inner tube 21 to move to release the double-layer hot-melt stent 1. Figures 13 and 14 As shown, the inner tube 21 is provided with a groove 211 on the wall of the double-layer hot-melt bracket 1, and the groove 211 is provided along the axial direction of the inner tube 21. A limiting portion 212 is provided at one end of the inner tube 21 facing away from the groove 211. Figure 15 As shown, the outer tube 22 is a reducer and is connected to the Luer connector 4. The outer tube 22 includes a first section 221 and a second section 222. The inner diameter of the first section 221 is smaller than the inner diameter of the second section 222. The maximum size of the limiting portion 212 of the inner tube 21 is larger than the inner diameter of the first section 221 and smaller than the inner diameter of the second section 222. The outer tube 22 drives the inner tube 21 to move via the limiting portion 212.

[0114] The inner tube 21 of the present application is provided with a slot 211, which can prevent the stent 1 from being locked in the lumen of the inner tube 21 due to the large radial force of the stent during the release process.

[0115] In this embodiment, the length of the slot 211 along the axial direction of the inner tube 21 is 5 mm to 50 mm, for example, 10 mm, 15 mm, 20 mm, 30 mm, 38 mm, 45 mm, etc. The width of the slot 211 is 0.1 mm to 1 mm, for example, 0.2 mm, 0.5 mm, 0.8 mm, etc. In actual use, the width and length are proportional, that is, when the length is small, the width is also small; when the length is large, the width is also relatively large. Overall, the slot 211 can prevent the stent 1 from locking in the lumen of the inner tube 21 due to the large radial force of the stent during the release process, while also ensuring the strength of the inner tube 21.

[0116] In this embodiment, the groove 211 is provided on the wall of the end portion of the inner tube 21 and is connected to the corresponding end surface of the inner tube 21 to facilitate the release of the stent.

[0117] In this embodiment, the material of the outer tube 22 can be: polyamide (PA), block polyetheramide resin (PEBAX), or polyurethane (PU), etc., and the material of the inner tube 21 is polytetrafluoroethylene (PTFE) or other medical materials.

[0118] In this embodiment, Figures 16 to 18This is a schematic diagram of the loading process of the double-layer hot melt stent 1 of the present application. The stent 1 is first compressed and loaded into the balloon 3. The inner cavity of the balloon 3 is provided with a guide wire 5, which is connected to the Luer connector 4 and passes through the inner tube 21. Figure 16 The Luer connector 4 and the stent 1 loaded on the balloon 3 are positioned at either end of the inner tube 21. The inner tube 21 is then moved so that the stent 1 and balloon 3 are positioned within the inner tube 21, at the location where the slot 211 is located. At this point, the inner tube 21 wraps around the compressed surface of the stent 1. The outer tube 22 is then inserted over the inner tube 21, extending from the stent 1 and balloon 3. A developing ring 6 is positioned at the end of the first section 221 of the outer tube 22, which has a smaller inner diameter. The developing ring 6 is used to display images. The minimum inner diameter of the outer tube 22 is greater than the outer diameter of the inner tube 21.

[0119] In this embodiment, Figures 19 to 21 Schematic diagram of the release process of the double-layer hot-melt stent 1 of the present application. When the stent 1 needs to be released, the outer tube 22 moves toward the Luer connector 4 under the action of external force. Since the inner tube 21 is provided with a limiting portion 212 and the outer tube 22 is a reducer, when the outer tube 22 moves to the position shown in FIG. Figure 20 When in the position shown, the outer tube 22 will drive the limiting portion 212 of the inner tube 21 to move together, thereby driving the inner tube 21 to move toward the Luer connector 4. As the inner tube 21 moves, the compressed stent 1 gradually breaks away from the wrapping of the inner tube 21, thereby completing the release of the stent 1. During this release process, since the inner tube 21 is provided with a groove 211, the stent 1 can be prevented from being subjected to a large radial force applied by the balloon 3 during the release process, causing the stent 1 to be locked in the lumen of the inner tube 21.

[0120] In summary, the double-layer hot-melt stent 1 proposed in the present application includes a frame 10, a porous fiber membrane 20 and a drug coating 30. The frame 10 is cylindrical and includes an inner frame 101 and an outer frame 102. The inner frame 101 is located inside the outer frame 102 and contacts the outer frame 102 to form a cross-net structure. The frame 10 adopts a double-layer structure, and the inner frame 101 and the outer frame 102 form a cross-net structure, which can improve the strength of the stent and increase the radial support force of the stent. The position where the inner frame 101 contacts the outer frame 102 is hot-melt connected. The hot-melt connection makes the connection between the inner frame 101 and the outer frame 102 more firm, further enhancing the strength of the frame 10. The porous fiber membrane 20 is arranged on the surface of the frame 10. The porosity of the porous fiber membrane 20 is greater than 70%, and the material of the porous fiber membrane 20 is a biodegradable material. Both the frame 10 and the porous fiber membrane 20 are made of biodegradable materials. The stent 1 degrades in the human body, preventing long-term irritation to the fallopian tube tissue and the occurrence of an inflammatory response. The drug coating 30, distributed within the pores of the porous fiber membrane 20, prevents cell and tissue adhesion and proliferation on the stent surface, thus preventing postoperative fallopian tube tissue proliferation on the stent surface and secondary obstruction of the fallopian tube lumen.

[0121] The manufacturing method of the double-layer hot-melt stent 1 proposed in this application includes the following steps: Step S1: Using a biodegradable material to make a frame 10; Step S2: Forming a porous fiber membrane 20 on the surface of the frame 10. Using biodegradable materials to make the frame 10 and the porous fiber membrane 20 allows the stent 1 to degrade in the human body, thereby preventing long-term irritation of the fallopian tube tissue by the stent 1 and the occurrence of an inflammatory reaction; Step S3: Preparing a solution of a drug coating 30, and impregnating the drug coating 30 into the pores of the porous fiber membrane 20 using a vacuum impregnation method. Impregnating the drug coating 30 into the pores of the porous fiber membrane 20 is a simple method with good impregnation effect, which can prevent adhesion and prevent postoperative proliferation of fallopian tube tissue on the surface of the stent 1, resulting in secondary blockage of the lumen.

[0122] The double-layer hot-melt stent release device proposed in this application comprises the double-layer hot-melt stent 1 described above and a catheter 2. The catheter 2 comprises an inner tube 21 and an outer tube 22. The double-layer hot-melt stent 1 is disposed within the inner tube 21, and the outer tube 22 drives the inner tube 21 to move, thereby releasing the double-layer hot-melt stent 1. The inner tube 21 has a groove 211 formed on the wall of the corresponding double-layer hot-melt stent 1, and the groove 211 is arranged axially along the inner tube 21. This prevents the stent 1 from becoming locked within the lumen of the inner tube 21 due to the large radial force exerted on the stent during release.

[0123] It is understandable that the various embodiments / implementations provided in this application can be combined with each other without causing any contradiction, and they will not be illustrated one by one here.

[0124] In the exemplary embodiments described above, the double-layer hot-melt stent, manufacturing method, and release device proposed in this application are described using fallopian tube applications as an example. Those skilled in the art will readily appreciate that various modifications, additions, substitutions, deletions, or other changes may be made to the specific embodiments to apply the design of this application to other locations, and such modifications remain within the scope of the principles of the double-layer hot-melt stent, manufacturing method, and release device proposed in this application.

[0125] It should be noted that the double-layer hot-melt stent, manufacturing method, and release device shown in the drawings and described in this specification are merely examples of many double-layer hot-melt stents, manufacturing methods, and release devices that can employ the principles of the present application. It should be clearly understood that the principles of the present application are in no way limited to any detail or component of the double-layer hot-melt stent, manufacturing method, and release device shown in the drawings or described in this specification.

[0126] In the application examples, the terms "first", "second", and "third" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance; the term "plurality" refers to two or more, unless otherwise expressly defined. Terms such as "installed", "connected", "connected", and "fixed" should be understood in a broad sense. For example, "connected" can mean a fixed connection, a detachable connection, or an integral connection; "connected" can mean a direct connection or an indirect connection through an intermediate medium. For those skilled in the art, the specific meanings of the above terms in the application examples can be understood according to the specific circumstances.

[0127] In the description of the application embodiments, it should be understood that the terms "up", "down", "left", "right", "front", "back", "top", "bottom", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the application embodiments and simplifying the description, rather than indicating or implying that the device or unit referred to must have a specific direction, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the application embodiments.

[0128] In the description of this specification, the terms "one embodiment", "some embodiments", "specific embodiments", etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the application embodiment. When introducing the elements / components / etc. described and / or illustrated herein, the terms "one", "an", and "above" are used to indicate the presence of one or more elements / components / etc. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples.

[0129] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A double-layer hot-melt stent, characterized in that: include: The frame comprises a cylindrical inner frame and a cylindrical outer frame, wherein the inner frame is located within the outer frame and contacts the outer frame to form a mesh structure, wherein the inner frame and the outer frame are connected by heat fusion at a location where the inner frame contacts the outer frame, and the frame is made of a biodegradable material; A porous fiber membrane is disposed on the surface of the frame, wherein the porosity of the porous fiber membrane is greater than 70%, and the material of the porous fiber membrane is a biodegradable material; The drug coating is distributed in the pores of the porous fiber membrane and can prevent cells and tissues from adhering to and proliferating on the surface of the stent.

2. The double-layer hot-melt stent according to claim 1, characterized in that: The inner layer frame and the outer layer frame are formed by winding a same wire, and the wire is first wound to form one of the inner layer frame and the outer layer frame, and then wound to form the other one.

3. The double-layer hot-melt stent according to claim 2, characterized in that: The inner layer frame includes a plurality of inner layer threads parallel to each other, and the inner layer threads are inclined in a first direction relative to the central axis of the inner layer frame; the outer layer frame includes a plurality of outer layer threads parallel to each other, and the outer layer threads are inclined in a second direction relative to the central axis of the outer layer frame, and the second direction is opposite to the first direction.

4. The double-layer hot-melt stent according to any one of claims 1 to 3, characterized in that: The material of the frame includes polylactic acid-glycolic acid copolymer and nano-hydroxyapatite.

5. The double-layer hot-melt stent according to any one of claims 1 to 3, characterized in that: The pore size of the porous fiber membrane is 280nm-350nm.

6. A method for manufacturing a double-layer hot-melt stent according to any one of claims 1 to 5, characterized in that: include: Step S1: making the frame; Step S2: forming the porous fiber membrane on the surface of the frame; Step S3: preparing a solution of the drug coating, and impregnating the drug coating into the pores of the porous fiber membrane using a vacuum impregnation method.

7. The method for manufacturing a double-layer hot-melt stent according to claim 6, wherein: Step S1 includes: Step S11: using biodegradable materials to make silk threads; Step S12: On the braided tool, firstly winding the wire to form one of the inner layer frame and the outer layer frame, and then winding to form the other one, to obtain a frame intermediate structure; Step S13: Assemble the intermediate frame structure into a heat shrink tube and heat it so that the inner frame and the outer frame are welded together at the contact position to form the frame.

8. The method for manufacturing a double-layer hot-melt stent according to claim 7, wherein: Step S12 includes: on the weaving tool, winding the wire along the circumference at an angle inclined in a first direction relative to the central axis of the inner frame to form the inner frame, and then winding the wire along the circumference at an angle inclined in a second direction relative to the central axis of the outer frame to form the outer frame, and the second direction is opposite to the first direction.

9. The method for manufacturing a double-layer hot-melt stent according to claim 7 or 8, wherein: The diameter of the silk thread is 180um-220um.

10. The method for manufacturing a double-layer hot-melt stent according to claim 6, wherein: Step S2 includes: Step S21: preparing a biodegradable material solution; Step S22: assembling the frame onto an electrospinning device, and weaving the porous fiber membrane on the surface of the frame.

11. The method for manufacturing a double-layer hot-melt stent according to claim 6, wherein: Step S3 includes: Step S31: uniformly mixing rapamycin and hyaluronic acid to form the drug coating solution; Step S32: impregnating the drug coating into the pores of the porous fiber membrane using a vacuum impregnation method, and performing freeze-drying treatment.

12. The method for manufacturing a double-layer hot-melt stent according to claim 11, wherein: The freeze-drying process includes multiple processing stages with different temperatures.

13. A double-layer hot-melt stent release device, characterized in that: include: The double-layer hot-melt stent according to any one of claims 1 to 5; The catheter comprises an inner tube and an outer tube, wherein the inner tube is disposed within the outer tube, the double-layer hot-melt stent is disposed within the inner tube, and the outer tube drives the inner tube to move to release the double-layer hot-melt stent; Wherein, a groove is provided on the tube wall of the inner tube corresponding to the double-layer hot-melt bracket, and the groove is provided along the axial direction of the inner tube.

14. The double-layer hot-melt stent release device according to claim 13, wherein: The length of the slot along the axial direction of the inner tube is 5 mm to 50 mm, and the width of the slot is 0.1 mm to 1 mm.

15. The double-layer hot-melt stent release device according to claim 13, wherein: The groove is provided on the tube wall of the end portion of the inner tube and is connected to the end surface corresponding to the end portion of the inner tube.

16. The double-layer hot-melt stent release device according to any one of claims 13 to 15, characterized in that: The outer tube includes a first section and a second section, the inner diameter of the first section is smaller than the inner diameter of the second section, a limiting portion is provided at one end of the inner tube, the maximum size of the limiting portion is larger than the inner diameter of the first section and smaller than the inner diameter of the second section, and the outer tube drives the inner tube to move through the limiting portion.

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