An artificial heart valve material, a method of preparation and an artificial heart valve device

Abstract

This invention relates to an artificial heart valve material, its preparation method, and an artificial heart valve device, belonging to the field of medical polymer materials and medical device technology. The main technical solution adopted is as follows: the artificial heart valve material is a composite structure film; the composite structure film includes a support layer located in the middle and encapsulation layers located on both sides of the support layer; the support layer is a porous polytetrafluoroethylene (PTFE) membrane; the encapsulation layers are polyurethane (PU) membranes; the polyurethane in the encapsulation layers permeates into the micropores of the porous PTFE membrane, forming a physically interpenetrating structure. This invention mainly solves the problem of insufficient bonding strength between polyurethane and PTFE in traditional composite methods. The valve material of this invention, used in the preparation of artificial heart valve devices, possesses good fatigue and tear resistance. When microcracks develop in the valve leaflets under long-term fatigue operation, this material can prevent the microcracks from expanding, effectively improving the fatigue life of the artificial heart valve device.

Description

Technical Field

[0001] This invention relates to the field of medical polymer composite materials and medical device technology, and in particular to an artificial heart valve material and its preparation method, and an artificial heart valve device. Background Technology

[0002] Heart valve disease is a common and serious cardiovascular disease. With the aging population and the high incidence of cardiovascular diseases, the global demand for valve replacement surgery is increasing year by year. Traditional valve replacement devices are mainly divided into two categories: mechanical valves and bioprosthetic valves. Mechanical valves have the advantages of high durability and long service life, but patients need to take anticoagulants for a long time, which increases the risk of bleeding and the burden of compliance. Bioprosthetic valves are derived from animal tissue or decellularized biological scaffolds, and have the advantages of good blood compatibility and no need for long-term anticoagulation. However, due to the inevitable structural decay of tissue materials, their service life is usually only 10-15 years, which is difficult to meet the clinical needs of young patients or patients requiring long-term follow-up.

[0003] To overcome the limitations of existing valve devices, polymeric artificial heart valves have gradually become a research hotspot. In recent years, various synthetic polymeric materials have been used to replace natural tissue valves, with the expectation of combining good durability with excellent biocompatibility. Among them, polyethylene terephthalate, polytetrafluoroethylene, polyurethane, and polycaprolactone have been extensively explored and have shown promising prospects in experimental studies or early clinical trials.

[0004] However, single polymer materials generally suffer from insufficient fatigue performance, poor long-term stability, or mechanical properties that are incompatible with natural valves. Especially when homogeneous polymer materials develop cracks under cyclic loading, these cracks tend to propagate rapidly, potentially leading to valve failure or even endangering the patient's life. Against this backdrop, the development of composite polymer artificial heart valves is of great significance.

[0005] In summary, developing composite polymer heart valve leaflets that combine long-term stability, tear resistance, and excellent biocompatibility is an important development direction in the field of artificial valve technology, and also a key technological bottleneck in improving clinical treatment levels. Summary of the Invention

[0006] In view of this, the present invention provides an artificial heart valve material, a preparation method, and an artificial heart valve device, the main purpose of which is to improve the long-term stability, tear resistance, and biocompatibility of artificial heart valves.

[0007] To achieve the above objectives, the present invention mainly provides the following technical solutions:

[0008] On one hand, embodiments of the present invention provide an artificial heart valve material, wherein the artificial heart valve material is a composite structure film; wherein the composite structure film includes a support layer located in the middle position and wrapping layers located on both sides of the support layer;

[0009] The supporting layer is a porous polytetrafluoroethylene membrane; the encapsulation layer is a polyurethane membrane; and the polyurethane in the encapsulation layer permeates into the micropores of the porous polytetrafluoroethylene membrane to form a physically interpenetrating structure.

[0010] Preferably, the thickness of the porous polytetrafluoroethylene membrane is 5-100 μm; the pore size of the porous polytetrafluoroethylene membrane is 0.1-5 μm; and the porosity of the porous polytetrafluoroethylene is 50-90%.

[0011] Preferably, the total thickness of the composite structure film is 0.05-0.5 mm, the tensile strength is 5-50 MPa, the tensile modulus is 1-15 MPa, and the tear strength is > 40 N / mm.

[0012] Preferably, the method for preparing the artificial heart valve material includes the following steps:

[0013] First coating step: Coating polyurethane solution onto the substrate to obtain a polyurethane solution wet film;

[0014] Placing a porous polytetrafluoroethylene membrane: The fixed porous polytetrafluoroethylene membrane is placed on the wet film of the polyurethane solution, and after drying, a first composite membrane is obtained;

[0015] The second coating step: The polyurethane solution is coated on the upper side of the porous polytetrafluoroethylene membrane of the first composite membrane to form a polyurethane solution wet film on the upper side of the porous polytetrafluoroethylene membrane. After drying, the second composite membrane is obtained.

[0016] Drying treatment: The second composite membrane is dried; then, after the dried second composite membrane is placed at room temperature, the second composite membrane is removed from the substrate to obtain the artificial heart valve material.

[0017] Preferably, the polyurethane solution comprises, by mass fraction: 5-20 wt% polyurethane, 30-75 wt% N,N-dimethylformamide, and 15-50 wt% isopropanol.

[0018] Preferably, the preparation steps of the polyurethane solution include: first, adding polyurethane to N,N-dimethylformamide solvent and stirring at a temperature of 25-80°C to obtain a mixture; then, under room temperature and stirring conditions, adding isopropanol to the mixture and continuing to stir until the solution is clear to obtain a polyurethane solution.

[0019] Preferably, the fixed porous polytetrafluoroethylene membrane includes a frame and a porous polytetrafluoroethylene membrane fixed on the frame;

[0020] Preferably, the side length of the frame is 5-30cm;

[0021] Preferably, the porous polytetrafluoroethylene membrane is fixed to the frame by any one of the following methods: adhesive bonding, screw fixing, or clamping.

[0022] Preferably, in the first coating step, the thickness of the polyurethane solution wet film is 0.2-3 mm.

[0023] Preferably, in the second coating step, the thickness of the polyurethane solution wet film formed on the upper side of the porous polytetrafluoroethylene film is 0.2-3 mm.

[0024] Preferably, in the placement of the porous polytetrafluoroethylene membrane, the drying temperature is 25-80°C and the drying time is 0.5-4h; and / or in the second coating step, the drying temperature is 25-80°C and the drying time is 0.5-4h; and / or in the drying treatment step, the drying temperature is 60-120°C and the drying time is 4-24h.

[0025] On the other hand, embodiments of the present invention provide an artificial heart valve device, wherein the artificial heart valve device includes leaflets; wherein the leaflets are made of any of the artificial heart valve materials described above;

[0026] Preferably, the artificial heart valve device further includes: a valve frame and a covering; wherein, the assembly steps of the artificial heart valve device include: first sewing the covering to the outside of the valve frame, and then fixing the leaflet to the valve frame and the covering; preferably, the fixing method is any one of sewing, bonding, or clamping;

[0027] Preferably, the material used for covering the fabric is any one of polyethylene terephthalate, polypropylene, polytetrafluoroethylene, and nylon.

[0028] Preferably, the material of the petiole frame is any one of polyetheretherketone, nickel-titanium alloy, or cobalt-chromium alloy.

[0029] Compared with the prior art, the artificial heart valve material, preparation method, and artificial heart valve device of the present invention have at least the following beneficial effects:

[0030] On one hand, embodiments of the present invention provide an artificial heart valve material, wherein the artificial heart valve material is a composite structure film; wherein the composite structure film includes a support layer located in the middle and a wrapping layer located on both sides of the support layer; the support layer is a porous polytetrafluoroethylene (PTFE) membrane; the wrapping layer is a polyurethane membrane; wherein the polyurethane in the wrapping layer permeates into the micropores of the porous PTFE membrane, forming a physically interpenetrating structure. Here, the artificial heart valve material provided by the embodiments of the present invention is explained as follows: Because the polyurethane material in the wrapping layer of the above structure permeates into the pores of the porous PTFE membrane, the polyurethane has high elasticity, and PTFE has high toughness. The physically interpenetrating structure formed by the two effectively improves the bonding force between the membrane layers and enhances the overall strength; at the same time, its interpenetrating structure divides the valve material into micro-regions, and any polyurethane damage in one area will be fixed by the surrounding PTFE network, preventing the damage from expanding, thereby improving the fatigue life of the artificial heart valve device. Through the above-mentioned precise composite material structure design, the polymer material is endowed with higher strength, and its internal micro-defects can exist stably without expanding, avoiding devastating damage and reserving a time window for the rescue and subsequent treatment of patients.

[0031] On the other hand, embodiments of the present invention provide a method for preparing an artificial heart valve material, which mainly includes the following steps: coating a polyurethane solution onto a substrate to obtain a polyurethane solution wet film; placing a fixed porous polytetrafluoroethylene (PTFE) membrane on the polyurethane solution wet film, and drying it to obtain a first composite film; coating a polyurethane solution onto the upper side of the porous PTFE membrane of the first composite film to form a polyurethane solution wet film on the upper side of the porous PTFE membrane, and drying it to obtain a second composite film; and drying the second composite film to obtain the aforementioned artificial heart valve material. The preparation steps of this invention are simple and low-cost.

[0032] In another aspect, embodiments of the present invention provide an artificial heart valve device. This artificial heart valve device includes leaflets; the leaflets are made of the aforementioned artificial heart valve material; and the artificial heart valve device possesses good fatigue and tear resistance. When microcracks develop on the leaflets under long-term fatigue operation, the leaflet material can prevent the microcracks from expanding, effectively improving the fatigue life of the artificial heart valve device.

[0033] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0034] Figure 1 This is a flowchart illustrating the preparation method of an artificial heart valve material provided in this embodiment;

[0035] Figure 2 Figure B shows the morphology of the porous polytetrafluoroethylene membrane after fixation in Example 1; where Figure B is an enlarged view of Figure A.

[0036] Figure 3 This is a morphological image of a cross-section of an artificial heart valve material, in which... Figure 3 In Figure A, the gray vertical bar in the middle is the polytetrafluoroethylene support layer, and Figure B is an enlarged view of the white framed part in Figure A.

[0037] Figure 4 The tensile curve of the artificial heart valve material in Example 1;

[0038] Figure 5 The trouser-shaped tear curve of the artificial heart valve material prepared in Example 1;

[0039] Figure 6 The trouser-shaped tear curve of the artificial heart valve material was prepared for Comparative Example 1;

[0040] Figure 7 A photograph of the artificial heart valve device prepared in Example 3;

[0041] Figure 8 These are the hydrodynamic curves of the artificial heart valve device prepared in Example 3 tested on a pulsation stage;

[0042] Figure 9 These are actual images of artificial heart valve materials; among them, Figure 9 Figure A in the image is a photograph of an actual artificial heart valve material. Figure 9 Figure B in the image is a physical picture of the artificial heart valve material. Detailed Implementation

[0043] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the specific embodiments, structures, features, and effects according to the present invention will be described in detail below with reference to the accompanying drawings and preferred embodiments. In the following description, different "embodiments" or "embodiments" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0044] The development of composite polymer artificial heart valves is of great significance in addressing the problems mentioned in the background technology. By introducing multiphase composite structures into the material design, the overall mechanical properties of the valve leaflets can be significantly improved, enhancing tear resistance and fatigue resistance, thereby delaying crack initiation and propagation and extending the service life of the device. In particular, elastic polymers such as polyurethane possess excellent flexibility and film-forming properties, while polymers such as polytetrafluoroethylene are known for their chemical corrosion resistance and stability. Combining these two organically to form a complementary composite system promises to possess flexibility, durability, and anti-degradation properties. The technical solution of this invention is as follows:

[0045] This invention provides an artificial heart valve material, wherein the artificial heart valve material is a composite structure film; wherein the composite structure film includes a support layer located in the middle and wrapping layers located on both sides of the support layer;

[0046] The supporting layer is a porous polytetrafluoroethylene membrane; the encapsulation layer is a polyurethane membrane; and the polyurethane in the encapsulation layer permeates into the micropores of the porous polytetrafluoroethylene membrane to form a physically interpenetrating structure.

[0047] It should be noted that the artificial heart valve material provided in this embodiment of the invention adopts a composite structure of "intermediate support layer + two side wrapping layers". The support layer is made of porous polytetrafluoroethylene, with a thickness of 5-100μm and a pore size of 0.1-5μm, serving as a mechanical support framework. The wrapping layers are made of medical-grade polyurethane, which penetrates into the micropores of the support layer to form a physically interpenetrating structure. The total thickness of the final composite membrane is controlled at 0.05-0.5mm, ensuring a tensile strength of 5-50MPa, a tensile modulus of 1-15MPa, and a tear strength >40N / mm.

[0048] Here, an embodiment of the present invention provides a method for preparing an artificial heart valve material, such as... Figure 1 As shown, it includes the following steps:

[0049] First coating step: Coat the polyurethane solution onto a substrate (e.g., a flat glass plate) to obtain a wet polyurethane solution film.

[0050] The preparation steps of the polyurethane solution used in this embodiment of the invention are as follows: Weigh the components according to the mass percentages (polyurethane mass fraction: 5-20 wt%, N,N-dimethylformamide mass fraction: 30-75 wt%, isopropanol mass fraction: 15-50 wt%). First, add the polyurethane to the N,N-dimethylformamide and stir until dissolved at 25-80°C. After cooling to room temperature, slowly add the isopropanol while stirring, continuing to stir until the solution is clear, avoiding particulate impurities. It should be noted that if the amount of isopropanol is too small, the prepared solution will not be able to penetrate into the pores of the porous polytetrafluoroethylene membrane, resulting in poor adhesion of the composite membrane, which may eventually lead to delamination or membrane peeling. If the amount of isopropanol is too large, the prepared solution may not be able to dissolve completely, and excessive isopropanol will cause the polyurethane to precipitate from the solvent, thus making it impossible to coat the membrane.

[0051] Placement of porous polytetrafluoroethylene membrane: The fixed porous polytetrafluoroethylene membrane is placed on the wet film of the polyurethane solution, and after drying, the first composite membrane is obtained.

[0052] A frame with a side length of 5-30cm is selected, and the porous polytetrafluoroethylene film is stretched and fixed to the frame by means of adhesive, screw fixing or clamping to prevent the film from wrinkling during the subsequent coating process.

[0053] Here, the polyurethane solution is coated into a wet film with a thickness of 0.2-3 mm by means of coating methods such as blade coating, roller coating or spray coating.

[0054] The fixed porous polytetrafluoroethylene membrane is placed on the wet membrane and dried at a temperature of 25-80℃ for 0.5-4 hours to allow polyurethane to penetrate into the micropores of the polytetrafluoroethylene membrane.

[0055] Regarding the frame, the following should be noted: The hollow square frame made of metal or other rigid materials is mainly used to taut the polytetrafluoroethylene film and prevent deformation during coating.

[0056] The second coating step involves coating the polyurethane solution onto the upper side of the porous polytetrafluoroethylene membrane of the first composite membrane to form a wet polyurethane solution film on the upper side of the porous polytetrafluoroethylene membrane. After drying, the second composite membrane is obtained.

[0057] The thickness of the polyurethane solution wet film formed on the upper side of the porous polytetrafluoroethylene membrane is 0.2-3 mm.

[0058] The drying temperature is 25-80℃, and the drying time is 0.5-4h.

[0059] Drying treatment: The second composite membrane is dried, and then, after the dried second composite membrane is placed at room temperature, the second composite membrane is removed from the substrate to obtain the artificial heart valve material.

[0060] The drying process is carried out in a forced-air drying oven or a vacuum drying oven. The drying temperature is 60-120℃, and the drying time is 4-24 hours to completely remove solvent residue.

[0061] In another aspect, embodiments of the present invention provide an artificial heart valve device, wherein the artificial heart valve device includes leaflets; wherein the leaflets are made of any of the artificial heart valve materials described above;

[0062] Preferably, the artificial heart valve device further includes: a valve frame and a covering; wherein, the assembly steps of the artificial heart valve device include: first sewing the covering to the outside of the valve frame to ensure that the covering is not loose, then fixing the leaflets to the preset positions of the valve frame and the covering to ensure that the leaflet opening angle is accurate and without deviation; and then testing the mechanical properties (tear resistance, fatigue resistance), membrane bonding strength and hydrodynamic properties of the assembled heart valve device, and sterilizing and sealing it after it passes the test.

[0063] Preferably, the fixing method is any one of sewing, bonding, or clamping;

[0064] Preferably, the material used for covering the fabric is any one of polyethylene terephthalate, polypropylene, polytetrafluoroethylene, and nylon.

[0065] Preferably, the material of the petiole frame is any one of polyetheretherketone, nickel-titanium alloy, or cobalt-chromium alloy.

[0066] The present invention will be further illustrated below through examples:

[0067] Example 1

[0068] This embodiment provides a method for preparing an artificial heart valve material, the specific steps of which are as follows:

[0069] First coating step: The polyurethane solution is coated onto the glass substrate using a doctor blade coating method, wherein the coating thickness is controlled to be 1 mm, to obtain a wet film of polyurethane solution.

[0070] The polyurethane solution used in this embodiment was prepared as follows: 10g of medical-grade polyurethane particles were added to 40g of N,N-dimethylformamide, and stirred at 60°C for 2 hours until the polyurethane was completely dissolved, forming a homogeneous and transparent solution. After cooling to room temperature, 40g of isopropanol was slowly added to the transparent solution, and stirring was continued for 1 hour to obtain a clear polyurethane solution.

[0071] Placement of porous polytetrafluoroethylene membrane: The porous polytetrafluoroethylene membrane fixed on the frame is laid flat on the wet membrane surface and dried at 50°C for 2 hours to allow the polyurethane solution to penetrate into the micropores of the porous polytetrafluoroethylene membrane, thus obtaining the first composite membrane.

[0072] In this step, the following instructions are given regarding fixing the porous PTFE membrane to the frame: Select a porous PTFE membrane with a thickness of 20 μm and an average pore size of 2 μm, such as... Figure 2 As shown, the film is cut into 15cm × 15cm squares and tightened and fixed with a metal clamping frame to prevent the film from wrinkling.

[0073] Second coating step: A 1 mm thick wet film of polyurethane solution is coated again on the surface of the dried first composite film, and then dried at 50°C for 2 hours to obtain the second composite film.

[0074] Drying treatment: The second composite membrane is placed in a vacuum drying oven and dried at 80°C for 12 hours to ensure that the solvent is completely evaporated. After the dried second composite membrane is placed at room temperature, it is removed from the substrate to obtain a complete artificial heart valve material (polyurethane-polytetrafluoroethylene composite membrane).

[0075] Performance testing: The artificial heart valve material was cut with a blade, and the cross-sectional morphology was observed under a scanning electron microscope, such as... Figure 3 As shown, polyurethane is filled into the cavities of porous polytetrafluoroethylene.

[0076] The artificial heart valve material prepared in this embodiment was cut into dumbbell-shaped tensile specimens and subjected to tensile tests on a universal testing machine. The fracture strength of the prepared artificial heart valve material was 29.6 MPa, and the maximum elongation was 350% (see [reference]). Figure 4 (As shown).

[0077] The artificial heart valve material prepared in this embodiment was cut into trouser-shaped samples and subjected to a tear test on a universal testing machine. Figure 5 As shown, the maximum tear strength of the material is 90.1 MPa / mm.

[0078] Example 2

[0079] This embodiment provides a method for preparing an artificial heart valve material, the specific steps of which are as follows:

[0080] First coating step: The polyurethane solution is coated onto the glass substrate using a doctor blade coating method, wherein the coating thickness is controlled to be 0.5 mm, to obtain a wet film of polyurethane solution.

[0081] The polyurethane solution used in this embodiment was prepared as follows: 10g of medical-grade polyurethane particles were added to 50g of N,N-dimethylformamide, and stirred at 60°C for 2 hours until the polyurethane was completely dissolved, forming a homogeneous and transparent solution. After cooling to room temperature, 30g of isopropanol was slowly added to the transparent solution, and stirring was continued for 1 hour to obtain a clear polyurethane solution.

[0082] Placement of porous polytetrafluoroethylene membrane: The porous polytetrafluoroethylene membrane fixed on the frame is laid flat on the wet membrane surface and dried at 40°C for 2 hours to allow the polyurethane solution to penetrate into the micropores of the porous polytetrafluoroethylene membrane, thus obtaining the first composite membrane.

[0083] In this step, the following instructions are given regarding fixing the porous PTFE membrane to the frame: Select a porous PTFE membrane with a thickness of 20 μm and an average pore size of 2 μm, such as... Figure 2 As shown, the film is cut into 15cm × 15cm squares and tightened and fixed with a metal clamping frame to prevent the film from wrinkling.

[0084] Second coating step: A 0.5 mm thick wet film of polyurethane solution is coated again on the surface of the dried first composite film, and then dried at 40°C for 2 hours to obtain the second composite film.

[0085] Drying treatment: The second composite membrane is placed in a vacuum drying oven and dried at 80°C for 12 hours to ensure that the solvent is completely evaporated. After the dried second composite membrane is placed at room temperature, it is removed from the substrate to obtain a complete artificial heart valve material (polyurethane-polytetrafluoroethylene composite membrane).

[0086] Example 3

[0087] This embodiment provides an artificial heart valve device, which mainly includes the following steps:

[0088] A polyetheretherketone (PEEK) stent was selected; polyethylene terephthalate (PET) fabric was sewn onto the outside of the stent. The artificial heart valve material prepared in Example 1 was cut into leaflet shapes and sewn onto the stent using 6-0 polypropylene sutures to obtain a three-valve heart valve device, as shown below. Figure 7 As shown.

[0089] from Figure 8 It can be seen that the artificial heart valve device prepared in Example 3 has arterial pressure, ventricular pressure and blood flow velocity curves that are close to human physiological conditions under pulsation test, and can be used to replace human diseased valves.

[0090] Comparative Example 1

[0091] Comparative Example 1 describes a method for preparing an artificial heart valve material, which mainly includes the following steps:

[0092] 1) Preparation of polyurethane solution: Take 10g of medical-grade polyurethane granules, add 40g of N,N-dimethylformamide, stir at 60℃ for 2h until the polyurethane is completely dissolved to form a homogeneous and transparent solution.

[0093] 2) The above polyurethane solution is coated onto a glass substrate using a doctor blade coating method, with the coating thickness controlled at 2 mm, to obtain a polyurethane wet film; it is dried at 50°C for 2 hours; then the dried film is placed in a vacuum drying oven and dried at 80°C for 12 hours to ensure that the solvent is completely evaporated, thus obtaining the artificial heart valve material (polyurethane film).

[0094] 3) Performance Testing: The artificial heart valve material (polyurethane membrane) is cut into trouser-shaped samples and subjected to a tear test on a universal testing machine. Figure 6 As shown, the average tear strength of the single-phase polyurethane film is 22.5 MPa / mm.

[0095] Compared with the single-phase polyurethane membrane in Comparative Example 1, the polyurethane-porous polytetrafluoroethylene composite membrane of the present invention effectively improves the tear resistance of artificial heart valve materials. When this material is used to prepare a polymer artificial heart valve device, it can effectively improve the strength of the device, prevent micro-defects from rapidly expanding under fatigue stress and causing devastating damage, and reserve a time window for patient rescue and subsequent treatment.

[0096] Comparative Example 2

[0097] This comparative example provides a method for preparing an artificial heart valve material, the specific steps of which are as follows:

[0098] First coating step: The polyurethane solution is coated onto the glass substrate using a doctor blade coating method, wherein the coating thickness is controlled to be 1 mm, to obtain a wet film of polyurethane solution.

[0099] The polyurethane solution used in this comparative example was prepared as follows: 10g of medical-grade polyurethane granules were added to 40g of N,N-dimethylformamide, and stirred at 60℃ for 2 hours until the polyurethane was completely dissolved, forming a homogeneous and transparent solution. After cooling to room temperature, 5g of isopropanol was slowly added to the transparent solution, and stirring was continued for 1 hour to obtain a clear polyurethane solution.

[0100] Placement of porous polytetrafluoroethylene membrane: The porous polytetrafluoroethylene membrane fixed on the frame is laid flat on the wet membrane surface and dried at 50°C for 2 hours to allow the polyurethane solution to penetrate into the micropores of the porous polytetrafluoroethylene membrane, thus obtaining the first composite membrane.

[0101] In this step, the following instructions are given regarding fixing the porous PTFE membrane to the frame: Select a porous PTFE membrane with a thickness of 20 μm and an average pore size of 2 μm, such as... Figure 2 As shown, the film is cut into 15cm × 15cm squares and tightened and fixed with a metal clamping frame to prevent the film from wrinkling.

[0102] Second coating step: A 1 mm thick wet film of polyurethane solution is coated again on the surface of the dried first composite film, and then dried at 50°C for 2 hours to obtain the second composite film.

[0103] Drying treatment: The second composite membrane is placed in a vacuum drying oven and dried at 80°C for 12 hours to ensure that the solvent is completely evaporated, thus obtaining a complete artificial heart valve material (polyurethane-polytetrafluoroethylene composite membrane).

[0104] Performance testing:

[0105] like Figure 9 As shown in Figure B, the polyurethane-PTFE composite membrane prepared with the parameters in Comparative Example 2 exhibits poor bonding performance, with numerous internal bubbles and delamination. This is because the proportions of polyurethane, N,N-dimethylformamide, and isopropanol in Comparative Example 2 do not meet the requirement of "5-20 wt% polyurethane, 30-75 wt% N,N-dimethylformamide, and 15-50 wt% isopropanol." Consequently, the solution cannot penetrate the pores of the porous PTFE membrane, resulting in poor composite membrane bonding and ultimately leading to delamination or membrane peeling. Figure 9 The polyurethane-polytetrafluoroethylene composite film prepared according to the parameters of Example 1 in Figure A is uniform, semi-transparent, without layered bubbles, and has good bonding performance.

[0106] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. An artificial heart valve material, characterized in that, The artificial heart valve material is a composite structure film; wherein, the composite structure film includes a support layer located in the middle position and wrapping layers located on both sides of the support layer; The supporting layer is a porous polytetrafluoroethylene membrane; the encapsulation layer is a polyurethane membrane; and the polyurethane in the encapsulation layer permeates into the micropores of the porous polytetrafluoroethylene membrane to form a physically interpenetrating structure.

2. The artificial heart valve material according to claim 1, characterized in that, The thickness of the porous polytetrafluoroethylene membrane is 5-100 μm; the pore size of the porous polytetrafluoroethylene membrane is 0.1-5 μm; and the porosity of the porous polytetrafluoroethylene is 50-90%.

3. The artificial heart valve material according to claim 1 or 2, characterized in that, The composite film has a total thickness of 0.05-0.5 mm, a tensile strength of 5-50 MPa, a tensile modulus of 1-15 MPa, and a tear resistance of > 40 N / mm.

4. The method for preparing the artificial heart valve material according to any one of claims 1-3, characterized in that, The method for preparing the artificial heart valve material includes the following steps: First coating step: Coating polyurethane solution onto the substrate to obtain a polyurethane solution wet film; Placing a porous polytetrafluoroethylene membrane: The fixed porous polytetrafluoroethylene membrane is placed on the wet film of the polyurethane solution, and after drying, a first composite membrane is obtained; The second coating step: The polyurethane solution is coated on the upper side of the porous polytetrafluoroethylene membrane of the first composite membrane to form a polyurethane solution wet film on the upper side of the porous polytetrafluoroethylene membrane. After drying, the second composite membrane is obtained. Drying treatment: The second composite membrane is dried; then, after the dried second composite membrane is placed at room temperature, the second composite membrane is removed from the substrate to obtain the artificial heart valve material.

5. The method for preparing the artificial heart valve material according to claim 4, characterized in that, The polyurethane solution comprises, by mass fraction: 5-20 wt% polyurethane, 30-75 wt% N,N-dimethylformamide, 15-50 wt% isopropanol; Preferably, the preparation steps of the polyurethane solution include: first, adding polyurethane to N,N-dimethylformamide solvent and stirring at a temperature of 25-80°C to obtain a mixture; then, under room temperature and stirring conditions, adding isopropanol to the mixture and continuing to stir until the solution is clear to obtain a polyurethane solution.

6. The method for preparing the artificial heart valve material according to claim 4, characterized in that, The fixed porous polytetrafluoroethylene membrane includes a frame and a porous polytetrafluoroethylene membrane fixed on the frame. Preferably, the side length of the frame is 5-30cm; Preferably, the porous polytetrafluoroethylene membrane is fixed to the frame by any one of the following methods: adhesive bonding, screw fixing, or clamping.

7. The method for preparing the artificial heart valve material according to claim 4, characterized in that, In the first coating step: the thickness of the polyurethane solution wet film is 0.2-3 mm.

8. The method for preparing the artificial heart valve material according to claim 4, characterized in that, In the second coating step, a polyurethane solution wet film with a thickness of 0.2-3 mm is formed on the upper side of the porous polytetrafluoroethylene membrane.

9. The method for preparing the artificial heart valve material according to claim 4, characterized in that, In the placement of the porous polytetrafluoroethylene membrane, the drying temperature is 25-80℃, and the drying time is 0.5-4h; and / or In the second coating step, the drying temperature is 25-80℃, and the drying time is 0.5-4 hours; and / or In the drying process: the drying temperature is 60-120℃ and the drying time is 4-24h.

10. An artificial heart valve device, characterized in that, The artificial heart valve device includes leaflets; wherein the leaflets are made of the artificial heart valve material according to any one of claims 1-3; Preferably, the artificial heart valve device further includes: a valve frame and a covering; wherein, the assembly steps of the artificial heart valve device include: first sewing the covering to the outside of the valve frame, and then fixing the leaflet to the valve frame and the covering; preferably, the fixing method is any one of sewing, bonding, or clamping; Preferably, the material used for covering the fabric is any one of polyethylene terephthalate, polypropylene, polytetrafluoroethylene, and nylon. Preferably, the material of the petiole frame is any one of polyetheretherketone, nickel-titanium alloy, or cobalt-chromium alloy.

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