A biomimetic multilayer polymeric valve material, method of manufacture and use

Abstract

The application discloses a kind of bionic multilayer polymer valve materials, preparation method and application.The polymer valve material includes fiber layer, which is flexible fabric layer woven by fiber;Sponge layer, which is a porous polymer layer, is formed on the surface of the fiber layer and inside the pores;Ventricular layer, which is a continuous homogeneous polymer film layer, is formed on the outer surface of the sponge layer.The preparation method includes: selecting fabric, cutting and washing, then tensioning and fixing, as the fiber layer;Prepare polymer solution 1;Introduce the fiber layer into the polymer solution 1, place it in a constant temperature and humidity environment, and form a porous sponge layer on the surface of the fiber layer and in the pores by water vapor induced phase separation;Prepare polymer solution 2, prepare the ventricular layer polymer film, and attach it to the surface of the fiber layer-sponge layer composite material;Finally, solvent vapor treatment is carried out to obtain the bionic multilayer polymer valve material.The bionic multilayer polymer valve material obtained by the application has both flexibility and durability, and has a wide application prospect in the field of artificial heart valve.

Description

Technical Field

[0001] This invention relates to the field of medical implant technology, and in particular to a biomimetic multilayer polymer valve material, its preparation method, and its application. Background Technology

[0002] Heart valves are the "valve" in the heart that control the one-way flow of blood. They open and close approximately 3 billion times in a person's lifetime and have excellent fatigue resistance. However, due to congenital malformations or acquired diseases (such as stenosis or regurgitation), the original heart valves may lose their normal function, requiring replacement with artificial valves. The first generation of artificial valves were mechanical valves, made of metal or pyrolytic carbon. Mechanical valves have good durability, but require open-heart surgery for implantation, which is more invasive, and they are prone to thrombosis, requiring lifelong anticoagulation after surgery. The second generation of artificial valves are bioprosthetic valves, mainly made by sewing biological tissues such as bovine pericardium or porcine heart valves onto a valve frame. Bioprosthetic valves overcome some of the disadvantages of mechanical valves, such as being implantable through minimally invasive surgery, resulting in less trauma, and have good anticoagulation effects, eliminating the need for long-term anticoagulation therapy. However, they also have problems such as easy calcification, short lifespan, high cost, and high material dispersion.

[0003] In recent years, research focus has gradually shifted to third-generation artificial valves—polymer valves. Compared with biological valves, polymer valves not only possess excellent resistance to calcification, anticoagulation, and biocompatibility, but their mechanical properties can also be improved through molecular design and structural optimization. Furthermore, they are easier to mass-produce, thus reducing costs. Currently, polymer valve materials are mainly divided into two categories: homogeneous and composite. Homogeneous materials (such as polyurethane, polyethylene, polyvinyl alcohol, and silicone) typically have weak tear and fatigue resistance, making it difficult for valves made from them to meet high fatigue life requirements. Composite materials, by introducing reinforcing phases (such as natural / synthetic fibers and flexible fabrics), improve fatigue and tear resistance to some extent, but key issues remain in their application: their elastic modulus is 2-3 orders of magnitude higher than that of native valves, making it difficult to meet ideal hemodynamic requirements; their surface structure is rougher, increasing the risk of thrombosis; and interfacial defects easily form between the polymer phase and the reinforcing phase, reducing bonding strength and affecting structural stability.

[0004] Various polymer-based artificial heart valve materials have been reported in existing patent literature. For example, Chinese patent CN202310175450 discloses a three-layer biomimetic valve leaflet material with a fabric layer, a viscoelastic material layer, and a flexible surface layer. Its viscoelastic material layer is a dense coating, without a porous structure design, and the interlayer bonding is mainly achieved through physical encapsulation, resulting in limited interfacial bonding strength. Chinese patent CN202311798462 discloses a method for preparing a polymer artificial heart valve composite material. It uses poor solvent treatment to intercalate the polymer layers, improving the bonding between the polymer and fabric layers while ensuring the overall smoothness and flatness of the material. However, this invention does not feature functional differentiation in the composite material design; its polymer layer cannot provide mechanical cushioning, and the fatigue resistance of the composite material is not mentioned.

[0005] In summary, polymer valve materials for human applications still face many challenges. Therefore, it is of great significance to develop a polymer valve material with a multi-layered structure similar to natural heart valves, good interfacial bonding, and both flexibility and fatigue resistance. Summary of the Invention

[0006] In order to solve the problems existing in the prior art, the purpose of this invention is to provide a biomimetic multilayer polymer valve material, a preparation method and an application. The biomimetic multilayer polymer valve material obtained by this invention has both flexibility and durability, and has broad application prospects in the field of artificial heart valves.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: This invention first proposes a biomimetic multilayer polymer valve material with a three-layer structure design, comprising: The fiber layer is a flexible fabric layer woven from fibers; The sponge layer is a porous polymer layer formed on the surface of the fiber layer and inside its pores; The ventricular layer is a continuous homogeneous polymer film layer formed on the outer surface of the sponge layer; The sponge layer is prepared based on the principle of water vapor-induced phase separation and has a three-dimensional interconnected pore structure. The sponge layer penetrates into the fiber layer fabric and covers its yarns; The ventricular layer covers at least one side of the spongy layer and forms a fusion interface with the spongy layer.

[0008] Preferably, the sponge layer is a porous polymer with a three-dimensional interconnected pore structure, and its material composition is one or more of polycarbonate polyurethane, polyether polyurethane, polyester polyurethane, polyurea polyurethane, and styrene-isobutylene-styrene triblock copolymer.

[0009] Preferably, the fiber layer material is composed of one or more of the following: polypropylene, high molecular weight polyethylene, ultra-high molecular weight polyethylene, polyester, aramid, polyamide fiber, polyimide fiber, and spandex.

[0010] Preferably, the ventricular layer material comprises one or more of the following: polycarbonate polyurethane, polyether polyurethane, polyester polyurethane, polyurea polyurethane, and styrene-isobutylene-styrene triblock copolymer.

[0011] In the polymer valve, the thickness of the fibrous layer is 30–200 μm; the thickness of the spongy layer is 150–280 μm; and the thickness of the ventricular layer is 10–30 μm.

[0012] The present invention further proposes a method for preparing a biomimetic multilayer polymer valve material, comprising the following steps: (1) Cut, wash and stretch the fabric onto the mold frame, and dry it completely to serve as the fiber layer; (2) Dissolve the sponge layer polymer in an organic solvent system to obtain polymer solution 1; (3) Introduce a fiber layer into polymer solution 1 and place it in a constant temperature and humidity environment so that water vapor comes into contact with the polymer solution 1 and induces phase separation, forming a porous sponge layer on the surface and in the pores of the fiber layer, and obtaining a fiber layer-sponge layer composite material. (4) Prepare polymer solution 2, prepare ventricular layer polymer film, and attach the ventricular layer polymer film to the surface of the sponge layer; (5) Solvent vapor treatment is performed to form a fusion interface between the ventricular layer and the sponge layer, resulting in the final biomimetic multilayer polymer valve material.

[0013] The fabric mentioned in step (1) is a knitted or woven fabric, and the yarn fineness is 8D to 80D; when the fabric is a knitted fabric, its structure is plain weave, rib, double rib, or double reverse weave; when the fabric is a woven fabric, its structure is plain weave, twill weave, or satin weave. One or more layers of the above-mentioned fabric can be used as the fiber layer.

[0014] In step (1), the fabric is kept taut throughout the sponge layer formation process by pre-stretching and fixing it to a mold frame that does not react with the organic solvent system.

[0015] The organic solvent system described in step (2) contains at least one amphiphilic solvent (a solvent that is miscible with water and capable of dissolving the sponge layer polymer), and optionally contains an auxiliary solvent; Preferably, the amphiphilic solvent is composed of one or more of N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, N-methylpyrrolidone, acetone, tetrahydrofuran, and 1,4-dioxane; preferably, the auxiliary solvent is composed of one or more of dichloromethane, chloroform, 1,2-dichloroethane, trichloromethane, and cyclopentanone.

[0016] The preparation process of polymer solution 1 in step (2) is as follows: the sponge layer polymer (5-20 parts by weight) is mixed with the organic solvent system (80-95 parts by weight in total), and heated and stirred in a water bath (temperature 60℃, speed 100 r / min, stirring for 3 h) to obtain a uniform polymer solution 1.

[0017] In step (3), a fiber layer is introduced into the polymer solution 1. The fiber layer is in contact with the polymer solution 1 by immersion or dipping. The polymer solution 1 completely covers and wets the fiber layer.

[0018] Preferably, the range of constant temperature and humidity environment set in step (3) is: temperature 26℃~30℃, relative humidity 55%RH~90%RH; the porosity of the formed sponge layer porous material is 25%~80%, and the pore size is 10~50 μm.

[0019] The preparation process of polymer solution 2 in step (4) is as follows: mix ventricular layer polymer (10-20 parts by weight) with organic solvent (80-90 parts by weight), heat and stir in a water bath (temperature 60℃, speed 100 r / min, stirring for 3 h) to obtain uniform polymer solution 2; The organic solvent is composed of any one of N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, tetrahydrofuran, dioxane, and dichloromethane.

[0020] The method for preparing the ventricular layer polymer film in step (4) is as follows: cut two polytetrafluoroethylene films (30 cm × 30 cm), pour about 5 g of polymer solution 2 onto each film; use an adjustable coating tool to scrape a uniform solution film, wait for about 15 s for the organic solvent to evaporate, and obtain the polymer ventricular layer film.

[0021] The solvent vapor treatment method described in step (5) is as follows: the tetrahydrofuran solvent is heated to form vapor, and then the sponge layer-fiber layer composite material attached to the ventricular layer film is placed in it and fumigated for 30 to 120 seconds to make the interface between the ventricular layer and the sponge layer fuse and enhance the interlayer bonding of the polymer valve.

[0022] This invention also proposes an application of a biomimetic multilayer polymer valve material. By cutting the polymer valve material into heart valve leaflets and sewing them onto a metal stent to assemble an artificial heart valve, it not only meets the flexibility requirements of heart valves and achieves smooth opening and closing functions, but also has excellent resistance to crack propagation.

[0023] Compared with the prior art, the present invention has the following beneficial effects: (1) This invention simulates the multi-layered structure of the original heart valve by functionalizing the fibrous layer, sponge layer, and ventricular layer. The fibrous layer incorporates high-strength and tough fiber fabric to provide anti-fatigue and anti-tear functions; the sponge layer uses porous materials to buffer and absorb the dynamic load during valve opening and closing; the ventricular layer uses a biocompatible polymer film with excellent anticoagulant and anti-calcification properties. The synergistic effect of the three layers makes the overall mechanical behavior of the polymer film more consistent with the operating rules of the original valve.

[0024] (2) In the biomimetic multilayer polymer valve material of the present invention, the sponge layer is prepared based on the principle of water vapor-induced phase separation and has a three-dimensional interconnected pore structure; the sponge layer penetrates into the gaps of the fiber layer fabric and covers its yarns, providing a buffering and protective function. At the same time, solvent vapor treatment is used to form a fusion interface between the ventricular layer and the sponge layer, and the polymer valve layers are firmly bonded, improving the stability of the valve structure.

[0025] (3) The biomimetic multilayer polymer valve material of the present invention has both low modulus (less than 2 MPa) and high fatigue threshold (greater than 5000 J / m²), which not only meets the flexibility requirements of heart valves and can achieve smooth opening and closing function, but also has excellent fatigue resistance and crack propagation resistance. It has great potential for application in the field of artificial heart valves. Attached Figure Description

[0026] Figure 1 This is a structural diagram of the biomimetic multilayer polymer valve material of this invention.

[0027] Figure 2 This is a schematic diagram of the preparation process of the biomimetic multilayer polymer valve material of the present invention.

[0028] Figure 3 These are scanning electron microscope (SEM) images of the biomimetic multilayer polymer valve material in Example 1. (a) shows the surface of the fiber layer, and (b) shows a cross-section of the biomimetic multilayer polymer valve material.

[0029] Figure 4 This is a scanning electron microscope (SEM) image of the fusion interface formed between the sponge layer and the ventricular layer of the biomimetic multilayer polymer valve material in Example 1.

[0030] Figure 5These are scanning electron microscope (SEM) images of the sponge layer of the biomimetic multilayer polymer valve material in Examples 1 and 5.

[0031] Figure 6 This is the curve showing the relationship between the crack propagation rate and the energy release rate of the biomimetic multilayer polymer valve material in Example 1.

[0032] Figure 7 This is a photograph of an artificial heart valve made from the biomimetic multilayer polymer valve material described in Example 1.

[0033] Figure 8 This is a diagram showing the opening and closing state of the artificial heart valve made from the biomimetic multilayer polymer valve material in Example 1. Detailed Implementation

[0034] The present invention will now be further described with reference to the accompanying drawings and embodiments. The following examples are for illustrative purposes only and do not limit the scope of protection of the present invention.

[0035] like Figure 1 As shown, the biomimetic multilayer polymer valve material of the present invention is based on the multilayer structure and functional differentiation of natural heart valves, and mainly includes three layers: a fiber layer, which is a flexible fabric layer woven from fibers; a sponge layer, which is a porous polymer layer formed on the surface of the fiber layer and inside the pores; and a ventricular layer, which is a continuous homogeneous polymer film layer formed on the outer surface of the sponge layer.

[0036] Example 1: A method for preparing a biomimetic multilayer polymer valve material like Figure 2 As shown, it includes the following steps: The first step involves selecting a weft-knitted plain fabric blended from ultra-high molecular weight polyethylene and spandex fibers. After pre-stretching the fabric to 140 mm × 90 mm × 150 μm, the sheet is fixed onto a metal mold frame. The fabric is then washed sequentially with anhydrous ethanol and deionized water. Subsequently, it is placed in a forced-air drying oven at 50°C for 10 minutes to obtain a dried fabric, which serves as the fiber layer for later use.

[0037] In the second step, 20 g of polycarbonate polyurethane (PCU) particles were used as the polymer raw material for the sponge layer, and 40 g of N,N-dimethylformamide (DMF) and 140 g of tetrahydrofuran (THF) were used as the organic solvent system. They were added together into a sealed container and stirred continuously for 3 h in a water bath at 60°C to completely dissolve the polycarbonate polyurethane (PCU) and obtain a homogeneous polymer solution 1.

[0038] The third step involves setting up a suitable constant temperature and humidity incubator environment (temperature 30℃, relative humidity 60%RH). The fiber layer is placed in a glass container with a base area of ​​14.5 cm × 9.5 cm. Then, 6 g of polymer solution 1 is poured into a metal mold frame, ensuring the solution completely wets and covers the fiber fabric. The entire glass container is placed on a horizontal platform and covered with perforated plastic wrap to reduce airflow. Water vapor enters the top of the glass container through the perforations, gradually contacting the solution. Maintaining the constant temperature and humidity environment, the container is removed after 12 hours to obtain a porous sponge-fiber composite material.

[0039] In the fourth step, 10 g of polycarbonate polyurethane (PCU) particles were dissolved in 90 g of tetrahydrofuran (THF) solvent as the polymer raw material for the ventricular layer. The solution was heated and stirred in a water bath (60℃, 100 r / min, for 3 h) to obtain polymer solution 2. Two 30 cm × 30 cm polytetrafluoroethylene membranes were cut, and 5 g of polymer solution 2 was poured onto each membrane. A 30 μm thick layer of solution was coated using an adjustable coating tool, and the THF was allowed to evaporate for about 15 s to obtain the ventricular layer membrane. The obtained ventricular layer membrane was then smoothly and tightly attached to the upper and lower surfaces of the porous sponge-fiber composite material obtained in the previous step.

[0040] In the fifth step, tetrahydrofuran (THF) is heated to form vapor, and the porous sponge-fiber composite material with the ventricular layer membrane attached is placed in it for 60 seconds to enhance the interfacial bonding between the ventricular layer and the sponge layer. The final product is a polymer valve material with a smooth, continuous interface. The thicknesses of the three layers are: fiber layer 150 μm; sponge layer 250 μm; ventricular layer 15 μm.

[0041] The microstructure of the fiber layer surface and the cross-section of the biomimetic multilayer polymer valve in Example 1 were characterized using scanning electron microscopy, and the results are as follows: Figure 3 As shown. By Figure 3 From (a), it can be seen that the fabric yarn is made of a blend of two fibers (ultra-high molecular weight polyethylene fiber and spandex fiber), and its structure is a weft-knitted plain weave fabric with two main directions. Figure 3 As can be seen from (b): the sponge layer in the biomimetic multilayer polymer valve material obtained in Example 1 has a three-dimensional interconnected pore structure, which can penetrate into the fiber layer and cover the fabric yarn. Figure 4 This is a magnified view of the interface between the ventricular layer and the spongy layer. It can be seen that after treatment with solvent vapor (THF vapor), the spongy layer interface partially dissolves and grows on the ventricular layer, forming a fusion interface without a clear boundary, which is not a simple physical adhesion.

[0042] Example 2: A method for preparing a biomimetic multilayer polymer valve material This embodiment provides a method for preparing a biomimetic multilayer polymer valve material. The only difference between this method and Example 1 is that, in the first step, ultra-high molecular weight polyethylene plain weave fabric is selected as the fiber layer, and its dimensions after cutting and pre-stretching are 140 mm × 90 mm × 200 μm. Other operating steps are the same as in Example 1.

[0043] Example 3: A method for preparing a biomimetic multilayer polymer valve material This embodiment provides a method for preparing a biomimetic multilayer polymer valve material. The only difference between this method and Example 1 is that in the second step, 20 g of styrene-isobutylene-styrene triblock copolymer (SIBS) is selected as the polymer raw material for the sponge layer and dissolved in an organic solvent system composed of 40 g of tetrahydrofuran (THF) and 140 g of dichloromethane (CH2Cl2) as polymer solution 1. Other operating steps are the same as in Example 1.

[0044] Example 4: A method for preparing a biomimetic multilayer polymer valve material This embodiment provides a method for preparing a biomimetic multilayer polymer valve material. The only difference between this method and Example 1 is that in the fourth step, 10 g of polyether polyurethane (PEU) is selected as the ventricular layer polymer raw material and dissolved in 90 g of N,N-dimethylacetamide (DMAc) solvent to form polymer solution 2. Other operating steps are the same as in Example 1.

[0045] Example 5: A method for preparing a biomimetic multilayer polymer valve material The first step involves selecting a plain knit fabric blended from ultra-high molecular weight polyethylene and spandex fibers. The fabric is pre-stretched to 140 mm × 90 mm × 150 μm and then fixed onto a metal mold frame. The fabric is then washed sequentially with anhydrous ethanol and deionized water. Subsequently, it is placed in a forced-air drying oven at 50°C for 10 minutes to obtain a dried fabric layer. The dried fabric and mold frame are then placed on a 15 cm × 15 cm clean glass plate for later use.

[0046] The second step involves adding 20 g of polycarbonate polyurethane (PCU) particles as the polymer raw material for the sponge layer and 180 g of N,N-dimethylformamide (DMF) solvent as the organic solvent system into a sealed container. The mixture is then stirred continuously for 3 hours in a 60°C water bath to completely dissolve the PCU particles and obtain a homogeneous polymer solution 1.

[0047] The third step involves setting up a suitable constant temperature and humidity incubator environment (temperature 28℃, relative humidity 70%RH). Then, 6 g of polymer solution 1 is poured into the mold frame with the fiber layer fabric fixed in place. The metal mold frame and glass plate are gently shaken to ensure the solution completely wets and covers the fabric. A 20 cm × 15 cm × 7 cm glass box is placed upside down on the glass plate, allowing water vapor to enter from all sides and gradually come into contact with the solution (preventing a large amount of water vapor from directly contacting the solution from above, thus avoiding condensation and the formation of large pores). The constant temperature and humidity environment is maintained. After 12 hours, the composite material (porous sponge layer-fiber layer) is obtained.

[0048] In the fourth step, 10 g of polycarbonate polyurethane (PCU) particles were dissolved in 90 g of tetrahydrofuran (THF) solvent as the polymer raw material for the ventricular layer. The solution was heated and stirred in a water bath (60℃, 100 r / min, for 3 h) to obtain polymer solution 2. Two 30 cm × 30 cm polytetrafluoroethylene membranes were cut, and 5 g of polymer solution 2 was poured onto each membrane. A 30 μm thick layer of solution was coated using an adjustable coating tool, and the THF was allowed to evaporate for about 15 s to obtain the ventricular layer membrane. The obtained ventricular layer membrane was then smoothly and tightly attached to the upper and lower surfaces of the porous sponge-fiber composite material obtained in the previous step.

[0049] In the fifth step, tetrahydrofuran (THF) is heated to form vapor, and the porous sponge-fiber composite material with the ventricular layer membrane attached is placed in it for 60 seconds to enhance the interfacial bonding between the ventricular layer and the sponge layer. The final product is a polymer valve material with a smooth, continuous interfacial structure. The thicknesses of the three layers are: fiber layer 150 μm; sponge layer 280 μm; ventricular layer 15 μm.

[0050] Example 6: A method for preparing a biomimetic multilayer polymer valve material This embodiment provides a method for preparing a biomimetic multilayer polymer valve material. The difference between this method and Example 5 is that, in the first step, polyamide fiber (PA) knitted fabric is selected as the fiber layer, and its dimensions after cutting and pre-stretching are 140 mm × 90 mm × 180 μm; in the second step, 40 g of polycarbonate polyurethane (PCU) is selected as the raw material for the sponge layer and dissolved in an organic solvent system composed of 160 g of N,N-dimethylformamide (DMF) as polymer solution 1. Other operating steps are the same as in Example 5.

[0051] Example 7: A method for preparing a biomimetic multilayer polymer valve material This embodiment provides a method for preparing a biomimetic multilayer polymer valve material. The difference between this method and Example 5 is that in the fourth step, 20 g of polycarbonate polyurethane (PCU) is selected as the raw material for the ventricular layer and dissolved in 80 g of dimethyl sulfoxide (DMSO) solvent to form polymer solution 2. Other operating steps are the same as in Example 5.

[0052] Example 8: A method for preparing a biomimetic multilayer polymer valve material This embodiment provides a method for preparing a biomimetic multilayer polymer valve material. The difference between this method and Example 5 is that, in the first step, ultra-high molecular weight polyethylene plain weave fabric is selected as the fiber layer; and in the third step, the constant temperature and humidity environment is set to 26°C and 80%RH. Other operating steps are the same as in Example 5.

[0053] The microstructure of the sponge layer in the biomimetic multilayer polymer valve materials of Examples 1 and 5 was observed using a scanning electron microscope. The results are as follows: Figure 5 As shown, the sponge layer in Example 1 has a lower porosity of approximately 47% and an average pore diameter of 20 μm; the sponge layer in Example 5 has a higher porosity of approximately 73% and an average pore diameter of 25 μm. The porosity was calculated using the density method, obtained by measuring the apparent density and true density of the material.

[0054] Mechanical property tests were conducted on Examples 1 and 5. An electronic universal testing machine was used, with a test temperature of room temperature, a mechanical sensor range of 1000 N, and a loading speed of 30 mm / min. First, the porous materials of the sponge layers in both examples were tested, and the results are shown in Table 1. It can be seen that the sponge layer of Example 5 has lower elastic modulus and fracture toughness, which is due to its higher porosity, making the material softer.

[0055] Table 1 Mechanical properties of porous materials with sponge layer Elastic modulus (MPa) Fracture toughness (KJ / m2) Example 1 1.79 19.09 Example 5 1.17 12.30 Subsequently, the mechanical properties of the biomimetic multilayer polymer valve materials of Examples 1 and 5 were tested. The results are shown in Table 2. It can be seen that although the biomimetic multilayer polymer valve material of the present invention incorporates a fiber layer, its elastic modulus is still relatively low (less than 2 MPa). Meanwhile, the polymer valve materials of Examples 1 and 5 both exhibit high fracture toughness values ​​(greater than 90 KJ / m). 2 ).

[0056] Table 2 Mechanical properties of biomimetic multilayer polymer valve materials Elastic modulus (MPa) Fracture toughness (KJ / m2) Example 1 1.94 101.68 Example 5 1.63 93.09 In addition, the ability of the biomimetic multilayer polymer valve material in Example 1 to resist crack propagation under cyclic loading was tested. Figure 6The relationship curve between crack propagation rate and energy release rate is given. It can be seen that at a higher energy release rate (6350 J / m), 2 Under these conditions, the crack propagation rate is relatively high (6.9 × 10⁻⁶). -6 mm / cycle); when the energy release rate is approximately 5000 J / m 2 At that time, the crack propagation rate was less than 1.0 × 10⁻⁶. -6 At a rate of mm / cycle, the crack can be considered macroscopically as not propagating. Therefore, this polymer valve material has a high fatigue threshold (greater than 5000 J / m). 2 ).

[0057] Example 9: In vitro fatigue testing of a biomimetic multilayer polymer valve material applied to artificial heart valves. The biomimetic multilayer polymer valve material from Example 1 was cut into three valve leaflets and sewn onto a stainless steel metal stent to produce an artificial heart valve. Figure 7 As shown. Figure 8 This is a diagram showing the opening and closing state of the artificial heart valve under pulsating flow. It can be seen that, due to the combination of low modulus (less than 2 MPa) and high fatigue threshold (greater than 5000 J / m²) of the biomimetic multilayer polymer valve material of this invention, the fabricated artificial heart valve exhibits excellent opening and closing morphology. Furthermore, the fabricated artificial heart valve was mounted on an in vitro accelerated fatigue testing machine and subjected to pulsating flow cycling at a frequency of 15 Hz to test its high-cycle fatigue life. The fabricated artificial heart valve passed 150 million cycles of high-cycle fatigue life testing, demonstrating the enormous potential of the biomimetic multilayer polymer valve material of this invention for application in artificial heart valves.

[0058] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A biomimetic multilayer polymer valve material, characterized in that, The polymer valve material has a three-layer structure design, including: The fiber layer is a flexible fabric layer woven from fibers; The sponge layer is a porous polymer layer formed on the surface of the fiber layer and inside its pores; The ventricular layer is a continuous homogeneous polymer film layer formed on the outer surface of the sponge layer; The sponge layer is prepared based on the principle of water vapor-induced phase separation and has a three-dimensional interconnected pore structure; the sponge layer penetrates into the fiber layer fabric and covers its yarns; The ventricular layer covers at least one side of the spongy layer and forms a fusion interface with the spongy layer.

2. The biomimetic multilayer polymer valve material according to claim 1, characterized in that, The sponge layer is a porous polymer with a three-dimensional interconnected pore structure, and its material composition includes one or more of the following: polycarbonate polyurethane, polyether polyurethane, polyester polyurethane, polyurea polyurethane, and styrene-isobutylene-styrene triblock copolymer. The fiber layer material comprises one or more of the following: polypropylene, high molecular weight polyethylene, ultra-high molecular weight polyethylene, polyester, aramid, polyamide fiber, polyimide fiber, and spandex. The ventricular layer material comprises one or more of the following: polycarbonate polyurethane, polyether polyurethane, polyester polyurethane, polyurea polyurethane, and styrene-isobutylene-styrene triblock copolymer.

3. The biomimetic multilayer polymer valve material according to claim 1, characterized in that, The thickness of the fiber layer is 30–200 μm; the thickness of the sponge layer is 150–280 μm; and the thickness of the ventricular layer is 10–30 μm.

4. A method for preparing the biomimetic multilayer polymer valve material according to any one of claims 1 to 3, characterized in that, Includes the following steps: (1) Cut, wash and stretch the fabric onto the mold frame, and dry it completely to serve as the fiber layer; (2) Dissolve the sponge layer polymer in an organic solvent system to obtain polymer solution 1; (3) Introduce a fiber layer into polymer solution 1 and completely cover and wet the fiber layer, and place it in a constant temperature and humidity environment so that water vapor comes into contact with the polymer solution 1 and induces phase separation, forming a porous sponge layer on the surface and in the pores of the fiber layer, and obtaining a fiber layer-sponge layer composite material. (4) Prepare polymer solution 2, prepare ventricular layer polymer film, and attach the ventricular layer polymer film to the surface of the fiber layer-sponge layer composite material; (5) Solvent vapor treatment is performed to form a fusion interface between the ventricular layer and the sponge layer, resulting in the final biomimetic multilayer polymer valve material.

5. The preparation method according to claim 4, characterized in that, The fabric mentioned in step (1) is a knitted or woven fabric with a yarn fineness of 8D to 80D. When the fabric is a knitted fabric, its structure is plain weave, rib, double rib, or double reverse weave. When the fabric is a woven fabric, its structure is plain weave, twill weave, or satin weave.

6. The preparation method according to claim 4, characterized in that, The organic solvent system described in step (2) contains at least one amphiphilic solvent that is miscible with water and capable of dissolving the sponge layer polymer, and may or may not contain an auxiliary solvent; The amphiphilic solvent is composed of one or more of N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, N-methylpyrrolidone, acetone, tetrahydrofuran, and 1,4-dioxane; the auxiliary solvent is composed of one or more of dichloromethane, chloroform, 1,2-dichloroethane, trichloromethane, and cyclopentanone. The preparation process of polymer solution 1 in step (2) is as follows: 5-20 parts by weight of sponge layer polymer and 80-95 parts by weight of organic solvent system are mixed, heated and stirred in a water bath to obtain uniform polymer solution 1.

7. The preparation method according to claim 4, characterized in that, In step (3), the constant temperature and humidity environment is set as follows: temperature 26℃~30℃, relative humidity 55%RH~90%RH; The porosity of the porous sponge layer formed in step (3) ranges from 25% to 80%, and the pore size is from 10 to 50 μm.

8. The preparation method according to claim 4, characterized in that, The preparation process of polymer solution 2 in step (4) includes: mixing 10-20 parts by weight of ventricular layer polymer with 80-90 parts by weight of organic solvent, heating and stirring in a water bath to obtain a uniform polymer solution 2. The organic solvent is any one of N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, tetrahydrofuran, dioxane, and dichloromethane.

9. The preparation method according to claim 4, characterized in that, Step (5) The solvent vapor treatment method is as follows: the tetrahydrofuran solvent is heated to form vapor, and then the sponge layer-fiber layer composite material attached to the ventricular layer film is placed in it and fumigated for 30 to 120 seconds.

10. The use of the biomimetic multilayer polymer valve material according to any one of claims 1 to 3 in the preparation of artificial heart valves.

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