Method for preparing a bio-medical textile composite film

Abstract

The application relates to a preparation method of a biomaterial fabric composite film, and relates to a material for medical implants. The method solves the problems of free edge tearing defects of high polymer polymer leaflets under long-term fatigue cycle load, fiber wear and breakage of fabric leaflets and non-developing property. Method 1: different fiber bundles and developing materials are used to weave a fabric middle layer; a film protection layer is prepared; two film protection layers with different thicknesses are respectively hot-pressed on the two sides of the fabric middle layer, and cutting is performed to complete the film. Method 2: fiber bundles and developing materials are woven and cut to obtain a fabric middle layer; a film protection layer is prepared and cut; the film protection layer is pasted on the two sides of the fabric middle layer to complete the film. The material has good blood compatibility, can guarantee high wear resistance, tear resistance and fatigue resistance, and will not change the original geometric design size under long-term cycle load. The fabric composite film in the application is suitable for valve materials.

Description

TECHNICAL FIELD

[0001] The present application relates to materials for medical implants; in particular to a method for preparing a bio-medical fabric composite film. BACKGROUND

[0002] Heart valve replacement is a very effective means for treating severe valve insufficiency or valve stenosis. According to the main material of the valve leaflet, there are mechanical valves and biological valves. The former has better durability, but needs to take anticoagulant drugs for life, otherwise thrombosis will occur; the latter has better blood compatibility, and postoperative anticoagulation only needs 3-6 months, but its durability is poor. Compared with traditional valve materials, fabric composite valve leaflets can have both the advantages of mechanical valves and biological valves, that is, good blood compatibility and strong fatigue resistance.

[0003] Heart valve replacement is a treatment for treating valve stenosis or valve insufficiency, and the main material of the implanted part is a synthetic material (alloy, high molecular polymer, etc.) artificial mechanical valve or artificial biological valve made of biological tissue (bovine pericardium, porcine pericardium, etc.). Mechanical valves have high durability and fatigue resistance, but patients must take anticoagulant drugs for life after implantation, and have the potential risk of thromboembolism, hemolysis and infective endocarditis, which will cause many inconveniences to the patient's life. The thrombosis rate of biological valves is low, and they have good hemodynamic performance and do not need to be anticoagulated for life, but the degradation and fatigue problem is a big challenge, and a considerable number of patients face the problem of needing a second operation. The main material of the mechanical valve is hard alloy or high polymer material, and the blood compatibility is its main disadvantage. For artificial biological valves, including surgical biological valves requiring open chest surgery and percutaneous transcatheter interventional biological valves, the main material of the valve leaflet is bovine pericardium, which is extracted from bovine pericardial tissue, screened and chemically treated to have good mechanical properties and blood compatibility. As a biological tissue extract, the extraction process of bovine pericardium is relatively complex, and the shelf life of the product is short. Moreover, the arrangement of collagen fibers inside the bovine pericardium is not uniform, which leads to the difference in local mechanical properties. This difference in mechanical properties between the valve leaflets can cause asynchrony in the opening and closing of the valve leaflets, affecting the stability of the flow field. It can even cause local vortex or unstable hemodynamic performance, thereby increasing the risk of thrombosis or hemolysis. After being implanted into the human body, it is more likely to produce fatigue tearing, wear and irreversible deformation under long-term opening and closing movement, eventually leading to the degradation of the structure and function of the artificial valve, changing the original hemodynamic performance, and possibly causing other complications.

[0004] According to ISO standard (ISO 5840-2), artificial biological valve needs to withstand fatigue cycle of at least 10 years, that is, at least 380 million times. Biological valve can fail in advance before the specified fatigue life is reached, and the reason can be due to fatigue failure of the valve under stress cycle, mutual contact wear between each valve or between the support structure, etc. If the three valve leaves are not absolutely uniform, the stress of the three valve leaves when opening and closing will be uneven, and the uneven stress is the main factor leading to valve fatigue. At the same time, if the stress load of one valve leaf is greater than that of the other two valve leaves, the valve leaf has a higher possibility of irreversible deformation than the other two valve leaves, and the deformation is greater than that of the other two valve leaves, eventually causing instability of the blood fluid mechanics performance.

[0005] Researchers have developed a variety of alternative materials for valve leaves, including high molecular polymer valve leaves and fabric valve leaves. The high molecular polymer valve leaf has a certain wear and anti-calcification ability, but under long-term fatigue cycle load, the free edge of the valve leaf will have a small tear defect, which has certain risk for long-term use. A variety of medical fibers as materials with high biocompatibility that can be implanted in the human body make the fabric also have the possibility of becoming a valve leaf replacement material. However, in the fatigue test, the material performs poorly, and fiber wear and breakage occur in the fatigue test. If implanted in the human body, this failure mode will cause the fiber to wear off and enter the blood circulation system, which will cause high risk to the patient's life and health. SUMMARY

[0006] The purpose of the present application is to solve the problems of free edge tear defects of high molecular polymer valve leaves, fiber wear and breakage of fabric valve leaves, and lack of visibility of valve leaf materials under long-term fatigue cycle load, and to provide a preparation method of a biomedical fabric composite material film.

[0007] The preparation method of the biomedical fabric composite material film is realized according to the following steps:

[0008] I. In the warp and weft directions, according to a constant interval, every 3-8 bundles of high melting point fiber bundles, add 1 bundle of low melting point fiber bundle, interval weaving, and weave in the developing material, to obtain the fabric middle layer;

[0009] II. Preparation of film protective layer: add developing substance to polyester, polycarbonate, polytetrafluoroethylene, polyurethane, gel, fluoro rubber or silicone rubber, mix uniformly, and then respectively prepare film protective layers, the thickness of the film protective layers is 0.03-0.1 mm and 0.01-0.05 mm respectively;

[0010] III. Heat pressing two kinds of film protective layers with different thickness on both sides of the above-mentioned fabric intermediate layer, obtaining a bio-medical fabric composite film with a total thickness of 0.1-0.5 mm, and then cutting into a general leaf shape, i.e. completing the preparation.

[0011] Further, the developing material in step one is platinum wire or gold wire, with a diameter of 0.05-0.15 mm; the ratio of the developing material to the fiber bundle is 1: (10-30) bundles.

[0012] Further, the high-melting-point fiber bundle and the low-melting-point fiber bundle in step one are combined by selecting two or more different melting-point fiber bundles from the group consisting of ultra-high molecular weight polyethylene fiber, polyester fiber, polycarbonate fiber, polytetrafluoroethylene fiber, polypropylene fiber, and polyamide fiber, and single hot-melt glue yarn.

[0013] Further, the interval weaving in step one is carried out by using weaving, knitting or electrospinning to weave multiple strands in a plain weave, with a weaving thickness of 0.05-0.3 mm and a weaving density of 30 g / m 2 ~ 90 g / m 2 .

[0014] Further, the developing substance in step two has a mass ratio of 1: (2-5) to polyester, polycarbonate, polytetrafluoroethylene, polyurethane, gel, fluororubber or silicone rubber; the developing substance is barium sulfate, platinum particles or gold particles, with an average particle size of 0.5-3 μm.

[0015] Further, the film protective layer in step two is a surface-intact film, a microporous structure film or a slit topological structure film.

[0016] The microporous structure film has a micropore diameter of 5-50 microns; and the microporous structure film is processed by laser, electric spark or stretching.

[0017] The slit topological structure film has a slit width of 10-200 microns and a length of 1000-5000 microns; and the slit topological structure film is processed by laser, electric spark or machining.

[0018] When the bio-medical fabric composite film is cut into leaf shapes, the direction of the slits is parallel to the symmetry axis of each leaf.

[0019] Further, the heat pressing in step two is carried out at a planar pressure of 10 kPa-1000 kPa, at a temperature higher than the melting temperature of the low-melting-point fiber bundle and lower than the melting temperature of the high-melting-point fiber bundle.

[0020] The bio-medical fabric composite film is prepared by the following steps:

[0021] I. The fiber bundle and developing material are then subjected to flat multi-strand weaving to obtain a fabric material with a thickness of 0.05-0.3 mm and a density of 30 g / m 2 ~ 90 g / m 2 The fabric material is then cut into a general leaf shape in a form in which the warp yarns and the weft yarns are parallel or perpendicular to the symmetry axis of the leaf, respectively, to obtain a fabric intermediate layer;

[0022] The developing material is platinum wire or gold wire, both with a diameter of 0.05-0.15 mm; the ratio of the developing material to the fiber bundle is 1: (10-30) bundles;

[0023] The yarn fineness of the yarns perpendicular to the direction of the symmetry axis of the leaf in the flat multi-strand weaving process is 50%-80% of the yarn fineness of the yarns parallel to the direction of the symmetry axis of the leaf;

[0024] II. The developing material is added to polyester, polycarbonate, polytetrafluoroethylene, polyurethane, gel, fluororubber or silicone rubber in a mass ratio of 1: (2-5), mixed uniformly and then prepared into a thin film protective layer with a microporous structure or a slit topology, and cut into a general leaf shape;

[0025] When the thin film protective layer has a slit topology, it is cut in a form in which the direction of the slit is parallel to the symmetry axis of each leaf;

[0026] In the preparation process, the thickness of the leaf B region is ensured to be 0.05-0.1 mm, and the thickness of the remaining regions is 0.01-0.05 mm;

[0027] III. The thin film protective layer is pasted on both sides of the above-mentioned fabric intermediate layer using an adhesive, thereby completing the preparation of the thin film of the biomedical fabric composite material;

[0028] The amount of the adhesive used is 0.5-1 mg / cm 2 in the leaf A region and 0.2-0.5 mg / cm 2 in the remaining regions.

[0029] Further, the fiber bundle in step I is ultra-high molecular weight polyethylene fiber, polyester fiber, polycarbonate fiber, polytetrafluoroethylene fiber, polypropylene fiber or polyamide fiber.

[0030] Further, the developing material in step II is barium sulfate, platinum particles or gold particles, all with an average particle size of 0.5-3 μm.

[0031] Further, the preparation of the adhesive in step three: the developing substance is added into the adhesive in a mass ratio of 1:(1-4) to form; the adhesive is one or a combination of several of water-based polyurethane, silicone rubber and low-temperature hot melt adhesive; and the coating mode of the adhesive is dot array or ultrasonic atomization.

[0032] Further, the adhesive in step three is cured at room temperature or a temperature higher than the melting temperature of the fiber bundle and the protective film by more than 10 DEG C.

[0033] The beneficial effects of the present application are:

[0034] 1. The present application proposes a new artificial valve replacement material, which avoids the shortcomings of other artificial heart valve materials, and has good blood compatibility, high wear resistance, tear resistance and fatigue resistance.

[0035] 2. The biological medical fabric composite film in the present application has good structural stability and is not prone to irreversible deformation during long-term use; the average service life of bovine pericardium material is 5-10 years, i.e. 1.9-3.8 billion times of human body circulation, and it will gradually produce irreversible deformation during long-term cyclic deformation, so that its shape is greatly changed compared with the design shape at the initial implantation stage, thereby affecting the hemodynamic performance of the valve product. The material in the present application can maintain the shape and fluid performance before and after fatigue under the same conditions or more severe conditions in the human body.

[0036] 3. The biological medical fabric composite film in the present application has strong fatigue resistance, aging resistance and wear resistance; under normal circumstances, the average service life of bovine pericardium material is 5-10 years, i.e. 1.9-3.8 billion times of human body circulation, and the material in the present application can work stably under the same conditions or more severe conditions in the human body, such as higher heart pressure load. The same accelerated fatigue test under severe conditions has been carried out, and the bovine pericardium valve is torn at about 300 million times, while the valve made of the material has no obvious wear and tear at 200 million times, and the fluid performance does not change greatly

[0037] 4、The biological medical fabric composite material film in the application has a thin film structure on the outer layer, which is more wear-resistant and anti-aging compared with a pure fabric material valve, and the thin film material is relatively easy to modify to improve the anti-calcification, anti-wear, anti-fatigue and blood compatibility, etc. The existing pure woven cloth made valve leaf has a woven cloth exposed, and the micro-porous structure caused by weaving is easy to cause thrombosis and calcification after implantation, and the pure woven structure has no protection and is extremely easy to wear. There are also valve leaves made of polyurethane rubber or silicone rubber, and the rubber-like structure is easy to relax, age and irreversibly deform after a long time of work, and the shape change of the valve leaf will cause the overall fluid performance to decrease, causing reflux or stenosis of blood flow, including but not limited to these negative effects.

[0038] 5、The biological medical fabric composite material film in the application uses developing material or developing particles, so that the material can be developed after being implanted into the human body, and the working state of the valve can be directly observed using a perspective device.

[0039] 6、The valve leaf material has a free edge tearing defect under a long-term fatigue cycle load, and the fabric valve leaf has fiber wear and breakage, the process is improved in the application, different melting point fiber bundles are used in the middle layer of the fabric, and fiber bundles with hot melting properties are added, so that multiple layers of structures can be combined together by hot pressing without spraying adhesive. The protective layer of the thin film is improved in the application, the curing speed of the adhesive is improved through the micro-porous structure and the regular slit structure, the overall flexibility of the thin film is improved, the bending stress is released, the anti-fatigue performance is increased, and the cell coverage speed after implantation is accelerated. According to the bending direction, the angle and installation direction of material cutting are designed in the application in combination with the working condition. And according to the load, bending or friction of different regions in use, the amount of adhesive required at different positions and the thickness of the outer film layer are designed to improve the bending performance, anti-wear and anti-fatigue performance of different regions.

[0040] The biological medical fabric composite material film in the application is suitable for valve materials. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 It is a schematic diagram of the biological medical fabric composite material film in Example 1, and the protective layer of the thin film is a thin film with a complete surface;

[0042] Figure 2 It is a schematic diagram of the biological medical fabric composite material film in Example 1, and the protective layer of the thin film is a slit topological structure thin film;

[0043] Figure 3 It is a structure schematic diagram of the biological medical fabric composite material film in Example 1 cut into a general valve leaf shape to make a valve product, and the protective layer of the thin film is a slit topological structure thin film.

[0044] Figure 4 The schematic diagram of the bio-medical fabric composite film in Example 2, the film protective layer is a microporous structure film;

[0045] Figure 5 The schematic diagram of the valve opening and closing state bending and contact friction area in Example 2, the first picture is the opening state, and the second picture is the closing state;

[0046] Figure 6 The schematic diagram of the valve leaflet bending and contact friction area in Example 2. DETAILED DESCRIPTION

[0047] The technical solution of the present application is not limited to the following specific embodiments, and also includes any combination between the specific embodiments.

[0048] Specific embodiment one: the preparation method of the bio-medical fabric composite film in the embodiment, which is realized according to the following steps:

[0049] I. In the warp and weft directions, according to a constant interval, every 3-8 bundles of high-melting-point fiber bundles, add 1 bundle of low-melting-point fiber bundles, carry out interval weaving, and weave into a developing material, to obtain a fabric intermediate layer;

[0050] II. Preparation of the film protective layer: add the developing substance into polyester, polycarbonate, polytetrafluoroethylene, polyurethane, gel, fluororubber or silicone rubber, mix uniformly, and then respectively prepare the film protective layer, the thickness of the film protective layer is respectively 0.03-0.1 mm and 0.01-0.05 mm;

[0051] III. Heat-press two kinds of thickness of the film protective layer on both sides of the above-mentioned fabric intermediate layer respectively, to obtain a bio-medical fabric composite film with a total thickness of 0.1-0.5 mm, and then cut into a general valve leaflet shape, that is, the preparation is completed.

[0052] The interval weaving in the embodiment carries out the specific value of 3-8 bundles of high-melting-point fiber bundles according to the actual required bonding strength of the material.

[0053] The developing material in step I and the developing substance in step II in the embodiment can also be used respectively.

[0054] After the bio-medical fabric composite film in the embodiment is cut into a general valve leaflet, prepared into a valve, and implanted into the human body, the working state of the valve can be directly observed through a perspective device.

[0055] Specific embodiment two: the difference between this embodiment and the first embodiment is that the developing material in step one is platinum wire or gold wire, with a diameter of 0.05-0.15 mm; the ratio of the developing material to the fiber bundle is 1: (10-30) bundles. The other steps and parameters are the same as those in the first embodiment.

[0056] Specific embodiment three: the difference between this embodiment and the first embodiment is that the high-melting-point fiber bundle and the low-melting-point fiber bundle in step one are composed of two or more different melting-point fiber bundles selected from the group consisting of ultra-high molecular weight polyethylene fiber, polyester fiber, polycarbonate fiber, polytetrafluoroethylene fiber, polypropylene fiber, polyamide fiber, and single hot-melt glue yarn. The other steps and parameters are the same as those in the first embodiment.

[0057] Specific embodiment four: the difference between this embodiment and the first embodiment is that the interval weaving in step one is plain multi-strand weaving using weaving, knitting, or electrostatic spinning, with a weaving thickness of 0.05-0.3 mm and a weaving density of 30-90 g / m 2 2 . The other steps and parameters are the same as those in the first embodiment.

[0058] Specific embodiment five: the difference between this embodiment and the first embodiment is that the developing material in step two has a mass ratio of 1: (2-5) to polyester, polycarbonate, polytetrafluoroethylene, polyurethane, gel, fluororubber, or silicone rubber; the developing material is barium sulfate, platinum particles, or gold particles, with an average particle size of 0.5-3 μm. The other steps and parameters are the same as those in the first embodiment.

[0059] Specific embodiment six: the difference between this embodiment and the first embodiment is that the film protective layer in step two is a surface-intact film, a microporous structure film, or a slit topological structure film.

[0060] The microporous structure film has a micropore diameter of 5-50 microns; and the microporous structure film is processed by laser, electric spark, or stretching.

[0061] The slit topological structure film has a slit width of 10-200 microns and a length of 1000-5000 microns; and the slit topological structure film is processed by laser, electric spark, or machining. The other steps and parameters are the same as those in the first embodiment.

[0062] In this embodiment, the microporous structure film or the slit topological structure film can release the stress of the film protective layer, increase the fatigue resistance, and accelerate the cell coverage rate after implantation into the human body.

[0063] ​The microporous structure film used in this embodiment can reduce the rigidity of the material and increase the flexibility when used as a valve.

[0064] Specific embodiment seven: this embodiment is different from specific embodiment six in that the film protective layer is a slit topological structure film, and the direction of the slit is parallel to the symmetry axis of each leaflet when the obtained bio-medical fabric composite film is cut into leaflets. The other steps and parameters are the same as those in specific embodiment six.

[0065] The purpose of this embodiment is to prevent stress concentration during bending deformation while reducing bending stiffness.

[0066] Specific embodiment eight: this embodiment is different from specific embodiment one in that the heat pressing in step two: the planar pressure is 10 kPa-1000 kPa, which is higher than the melting temperature of the low-melting-point fiber bundle and lower than the melting temperature of the high-melting-point fiber bundle. The other steps and parameters are the same as those in specific embodiment one.

[0067] The bonding strength and effect after heat pressing in this embodiment can be regulated by changing the amount and distribution density of the low-melting-point fiber bundle.

[0068] Specific embodiment nine: the preparation method of the bio-medical fabric composite film in this embodiment is realized according to the following steps:

[0069] I. The fiber bundle and the developing material are then subjected to plain multi-strand weaving to obtain a fabric material with a thickness of 0.05-0.3 mm and a density of 30 g / m 2 ~ 90 g / m 2 The fabric material is then cut into a general leaflet shape according to the forms that the warp yarn and the weft yarn are parallel or perpendicular to the symmetry axis of the leaflet, respectively, to obtain a fabric intermediate layer.

[0070] The developing material is platinum wire or gold wire, and the diameter of each is 0.05-0.15 mm; the ratio of the developing material to the fiber bundle is 1: (10-30) bundles;

[0071] The fineness of the yarns perpendicular to the direction of the symmetry axis of the leaflet in the plain multi-strand weaving process is 50%-80% of the fineness of the yarns parallel to the direction of the symmetry axis of the leaflet;

[0072] II. The developing material is added to polyester, polycarbonate, polytetrafluoroethylene, polyurethane, gel, fluororubber, or silicone rubber according to a mass ratio of 1: (2-5), and then mixed uniformly to prepare a film protective layer with a microporous structure or a slit topological structure, which is then cut into a general leaflet shape.

[0073] When the film protective layer is a slit topological structure, it is cut according to the form that the direction of the slit is parallel to the symmetry axis of each leaflet;

[0074] The thickness of the leaflet B region is 0.05-0.1 mm, and the thickness of the other regions is 0.01-0.05 mm during the preparation process;

[0075] III. The adhesive is used to paste the film protective layer on both sides of the above-mentioned fabric middle layer, thereby completing the preparation of the bio-medical fabric composite film;

[0076] The amount of the adhesive used in the leaflet A region is 0.5-1 mg / cm 2 , and the amount of the adhesive used in the other regions is 0.2-0.5 mg / cm 2 .

[0077] In the present embodiment, the leaflet B region: according to different valve size models, the region within 2-3 mm from the free edge (i.e. the shorter arc-shaped edge) of the leaflet is the B region, and the B region is in contact and friction with the corresponding positions of other leaflets during the opening and closing of the valve.

[0078] In the present embodiment, the leaflet A region: according to different valve size models, the region within 2-3 mm from the fixed edge (i.e. the longer arc-shaped edge) of the leaflet is the A region, and the edge of the A region is fixed on the valve support, and the A region mainly bears the bending load during the opening and closing of the valve.

[0079] Specific embodiment ten: the difference between the present embodiment and specific embodiment nine is that the fiber bundle in step one is an ultra-high molecular weight polyethylene fiber, a polyester fiber, a polycarbonate fiber, a polytetrafluoroethylene fiber, a polypropylene fiber, or a polyamide fiber. The other steps and parameters are the same as those in specific embodiment nine.

[0080] Specific embodiment eleven: the difference between the present embodiment and specific embodiment nine is that the mass ratio of the developing substance to polyester, polycarbonate, polytetrafluoroethylene, polyurethane, gel, fluororubber, or silicone rubber in step two is 1:(2-5); the developing substance is barium sulfate, platinum particles, or gold particles, and the average particle size is 0.5-3 μm. The other steps and parameters are the same as those in specific embodiment nine.

[0081] Specific embodiment twelve: the difference between the present embodiment and specific embodiment nine is that the preparation of the adhesive in step three: the developing substance is added to the adhesive in a mass ratio of 1:(1-4) to prepare; the adhesive is one or a combination of several of water-based polyurethane, silicone rubber, and low-temperature hot melt adhesive; and the coating method of the adhesive is dot matrix or ultrasonic atomization. The other steps and parameters are the same as those in specific embodiment nine.

[0082] Specific implementation method thirteen: the difference between this implementation method and specific implementation method nine is that the adhesive in step three is cured at room temperature or a temperature that is 10°C or more than the melting temperature of the fiber bundle and the film protective layer. The other steps and parameters are the same as those in specific implementation method nine.

[0083] The beneficial effects of the present application are verified by the following examples:

[0084] Example 1:

[0085] The preparation method of the bio-medical fabric composite film is realized according to the following steps:

[0086] I. In the warp and weft directions, 1 bundle of low-melting-point fiber bundle is added every 5 bundles of high-melting-point fiber bundle at constant intervals, interval weaving is performed, and a developing material is woven into the fabric middle layer;

[0087] II. Preparation of the film protective layer: the developing material is added to polycarbonate, and after mixing, the film protective layer is prepared, and the thickness of the film protective layer is 0.05 mm and 0.02 mm, respectively;

[0088] III. The two types of film protective layers with different thicknesses are hot-pressed on both sides of the above-mentioned fabric middle layer to obtain a bio-medical fabric composite film with a total thickness of 0.27 mm, and then it is cut into a general petal shape, i.e., the preparation is completed.

[0089] The developing material in step one of this example is gold wire, and the diameter is 0.1 mm; the ratio of the developing material to the fiber bundle is 1:10.

[0090] The high-melting-point fiber bundle in step one of this example is an ultrahigh molecular weight polyethylene fiber, and the low-melting-point fiber bundle is a single hot-melt glue yarn.

[0091] The interval weaving in step one of this example is flat multi-strand weaving using electrostatic spinning, and the weaving thickness is 0.2 mm, and the weaving density is 60 g / m 2 .

[0092] The mass ratio of the developing material to polycarbonate in step two of this example is 1:3; the developing material is barium sulfate, and the average particle size is 2 μm.

[0093] The film protective layer in step two of this example is a film with complete surface, a microporous structure film, or a slit topological structure film;

[0094] The micropore diameter of the microporous structure film is 20 microns; and the processing method of the microporous structure film is laser;

[0095] The slit width of the slit topological structure film is 100 microns, and the length is 2000 microns; the processing mode of the slit topological structure film is laser.

[0096] The above-mentioned film protective layer adopts a slit topological structure film, and when the obtained bio-medical fabric composite material film is cut into leaflets, the direction of the slit is parallel to the symmetry axis of each leaflet.

[0097] The heat pressing in step two of the embodiment is performed at a plane pressure of 100 kPa, a temperature higher than the melting temperature of the low-melting-point fiber bundle, and lower than the melting temperature of the high-melting-point fiber bundle.

[0098] The bio-medical fabric composite material film prepared in the embodiment, Figure 1 As shown, the film protective layer is a complete-surface film, the fabric intermediate layer is formed by arranging low-melting-point fiber bundles (black) and high-melting-point fiber bundles (white) in proportion, and no other adhesive is used between the film protective layer and the fabric intermediate layer.

[0099] The bio-medical fabric composite material film prepared in the embodiment, Figure 2 As shown, the film protective layer is a slit topological structure film; the slit topological structure film can release the stress of the film protective layer, increase the fatigue resistance, and accelerate the cell coverage rate after being implanted into the human body. The bio-medical fabric composite material film is cut into a general leaflet shape to form a valve product, and the structure is as shown in Figure 3 As shown, the outer hollow structure is a valve stent (a material of an existing structure), and the inner structure is three leaflets of the same shape, wherein the film protective layer of each leaflet is a slit topological structure, arranged in order and with the direction of the slit parallel to the symmetry axis of each leaflet.

[0100] Embodiment 2:

[0101] The method for preparing the bio-medical fabric composite material film is implemented in the following steps:

[0102] I. The fiber bundles and developing materials are subjected to plain multi-strand weaving to obtain a fabric material with a thickness of 0.2 mm and a density of 60 g / m 2 , and then cut into a general leaflet shape in the form that the warp yarns and the weft yarns are parallel or perpendicular to the symmetry axis of the leaflet respectively to obtain a fabric intermediate layer;

[0103] The developing materials are gold wires with a diameter of 0.1 mm; and the proportion of the developing materials to the fiber bundles is 1:10.

[0104] In the process of the plain multi-strand weaving, the fineness of the yarns perpendicular to the direction of the symmetry axis of the leaflet is 60% of the fineness of the yarns parallel to the direction of the symmetry axis of the leaflet.

[0105] II. The developing substance is added to the polycarbonate in a mass ratio of 1:3, mixed evenly to prepare the microporous structure film protective layer, and cut into the general leaflet shape;

[0106] The thickness of the leaflet B area is 0.05-0.1 mm, and the thickness of the remaining area is 0.01-0.05 mm in the preparation process;

[0107] III. The film protective layer is pasted on both sides of the above-mentioned fabric middle layer using the adhesive, thereby completing the preparation of the biomaterial fabric composite film;

[0108] The amount of the adhesive used in the leaflet A area is 0.5-1 mg / cm 2 , and the amount of the adhesive used in the remaining area is 0.2-0.5 mg / cm 2 .

[0109] The fiber bundle in step I of the embodiment is an ultra-high molecular weight polyethylene fiber.

[0110] The developing substance in step II of the embodiment is barium sulfate with an average particle size of 2 μm.

[0111] The preparation of the adhesive in step III of the embodiment: the developing substance is added to the adhesive in a mass ratio of 1:3 to prepare the adhesive; the adhesive is water-based polyurethane; and the coating method of the adhesive is ultrasonic atomization.

[0112] The adhesive in step III of the embodiment is cured at room temperature.

[0113] The biomaterial fabric composite film prepared in the embodiment, Figure 4 as shown in the figure, the film protective layer is a microporous structure film. The microporous structure not only accelerates the curing of the adhesive, but also releases the stress of the film to increase the fatigue resistance and accelerate the cell coverage rate after implantation into the human body.

[0114] The schematic diagram of the leaflet A area and the leaflet B area is shown in Figure 5 wherein the lower end of the leaflet is the fixed edge, the area close to the fixed edge is the A area, mainly for the bending load; the upper end of the leaflet is the free edge, and the area close to the free edge is the B area, mainly for the contact between the leaflets. Note: Figure 5 The hollow white part is the remaining area; the leaflet shape in the artificial heart valve product is an axisymmetric figure with two arc edges, wherein the longer arc edge is the fixed edge, and the shorter arc edge is the free edge.

[0115] The schematic diagram of the shape of the conventional valve product when opening and closing is shown in Figure 6Wherein the edge of the leaflet opening side is a free edge, and the other side fixed on the valve support is a fixed edge, wherein the area near the fixed edge is mainly subjected to bending load, and the area near the free edge is in contact and friction with each other when the leaflets are switched.

[0116] In this embodiment, the edge of the leaflet A area is fixed on the valve support, and the main load is bending load when the valve is opened and closed. In order to prevent the material from delaminating under the action of fatigue, more adhesive (0.5-1 mg / cm 2 ) is used in the A area, and less adhesive (0.2-0.5 mg / cm 2 ) is used in the rest of the positions to prevent the material stiffness from increasing after curing.

[0117] In this embodiment, the leaflet B area is in contact with the corresponding positions of other leaflets when the valve is opened and closed, and in order to increase the wear resistance of the outer film, the thickness (0.05-0.1 mm) of the positions (B area) that are in contact for a long time during the operation of the leaflet is increased to reduce the risk of wear, and the rest of the positions use a lower thickness (0.01-0.05 mm) to improve the flexibility of the material.

[0118] The prepared bio-medical fabric composite material film in this embodiment has good structural stability and is not prone to irreversible deformation during long-term use; the average service life of bovine pericardium material is 5-10 years, i.e. 1.9-3.8 billion times of human body circulation, and irreversible deformation will gradually occur during long-term period deformation, so that the shape is greatly changed compared to the design shape at the initial implantation. Thus affecting the hemodynamic performance of the valve product. The material in this embodiment can maintain the shape and fluid performance before and after fatigue under the same conditions or more severe conditions in the human body.

[0119] Strong anti-fatigue, aging and wear resistance; under normal circumstances, the average service life of bovine pericardium material is 5-10 years, i.e. 1.9-3.8 billion times of human body circulation, and the material in this embodiment can work stably under the same conditions or more severe conditions in the human body, such as higher heart pressure load. Accelerated fatigue tests have been conducted under the same severe conditions, and the bovine pericardium valve is torn at about 300 million times, while the valve made of the material is not significantly worn at 200 million times, and the fluid performance does not change greatly.

[0120] Good biocompatibility of the material; the middle layer and the film protection layer of the fabric in this embodiment are materials that have been verified to have good biocompatibility in international products and are widely used in the interventional field, and the combination of the two does not change the biocompatibility.

[0121] The prepared bio-medical fabric composite film in the embodiment has simple sterilization process, is relatively easy to preserve, can be preserved for a long time only under normal temperature and sterile conditions, and the sterilization process can be selected as standard ethylene oxide sterilization.

Claims

1. A method for preparing a biomedical fabric composite film, characterized in that... It is implemented in the following steps:

1. Along the warp and weft directions, at constant intervals, add one low-melting-point fiber bundle every five high-melting-point fiber bundles, perform interval weaving, and weave in developing material to obtain the middle layer of the fabric. II. Preparation of the thin film protective layer: The developing substance was added to polycarbonate, and after mixing, thin film protective layers were prepared with thicknesses of 0.05 mm and 0.02 mm, respectively.

3. Two thin film protective layers of different thicknesses are hot-pressed on both sides of the above-mentioned fabric middle layer to obtain a biomedical fabric composite film with a total thickness of 0.27 mm, which is then cut into a common leaflet shape to complete the preparation. The developing material mentioned in step one is gold wire, all with a diameter of 0.1 mm; the ratio of the developing material to the fiber bundle is 1 strand: 10 bundles. The high-melting-point fiber bundle mentioned in step one is ultra-high molecular weight polyethylene fiber, and the low-melting-point fiber bundle is single-strand hot melt adhesive yarn; The interval weaving described in step one involves using electrostatic spinning for plain weave multi-strand weaving, with a weave thickness of 0.2 mm and a weaving density of 60 g / m². 2 ; In step two, the mass ratio of the developing substance to polycarbonate is 1:3; the developing substance is barium sulfate with an average particle size of 2 μm. The thin film protective layer mentioned in step two is a thin film with an intact surface, a microporous structure thin film, or a slit topology structure thin film; The microporous structure film has a micropore diameter of 20 micrometers; the microporous structure film is processed by laser. The slit topology thin film has a slit width of 100 micrometers and a length of 2000 micrometers; the slit topology thin film is processed by laser. The hot pressing described in step three involves a planar pressure of 100 kPa, using a melting temperature higher than that of low-melting-point fiber bundles but lower than that of high-melting-point fiber bundles.

2. A method for preparing a biomedical fabric composite film, characterized in that... It is implemented in the following steps:

1. The fiber bundle and developing material are then subjected to plain weave multi-strand braiding to obtain a thickness of 0.2 mm and a density of 60 g / m³. 2 The fabric material is then cut into a general petal shape, with the warp and weft yarns parallel or perpendicular to the petal symmetry axis, to obtain the middle layer of the fabric. The developing material is gold wire, all with a diameter of 0.1 mm; the ratio of the developing material to the fiber bundle is 1 strand: 10 bundles. In the plain weave multi-strand weaving process, the yarn fineness perpendicular to the direction of the leaflet symmetry axis is 60% of the yarn fineness parallel to the direction of the leaflet symmetry axis; 2. Add the developing material to the polycarbonate at a mass ratio of 1:3, mix well, and prepare a microporous protective film layer, then cut it into a common leaflet shape. During the preparation process, the thickness of region B of the leaflet is ensured to be 0.05~0.1mm, and the thickness of the remaining regions is 0.01~0.05mm; 3. Using an adhesive, a protective film layer is pasted onto both sides of the above-mentioned intermediate layer of the fabric, thus completing the preparation of the biomedical fabric composite film; The amount of adhesive used: 0.5~1 mg / cm² in region A of the leaflet. 2 The dosage for other areas is 0.2~0.5 mg / cm³. 2 ; The fiber bundle mentioned in step one is ultra-high molecular weight polyethylene fiber; The developing substance mentioned in step two is barium sulfate, with an average particle size of 2 μm; The leaflet region B mentioned in step two: the upper end of the leaflet is the free edge, and the area near the free edge is region B; The adhesive in step three is prepared by adding the developing substance to the adhesive at a mass ratio of 1:3; the adhesive is water-based polyurethane; and the adhesive is applied by ultrasonic atomization. The adhesive used in step three is cured at room temperature; The leaflet region A mentioned in step three: The lower end of the leaflet is a fixed edge, and the area close to the fixed edge is region A.

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