Nanofiber composite membrane as well as preparation method and application thereof

Abstract

The invention provides a nanofiber composite membrane as well as a preparation method and application thereof. The nanofiber composite membrane comprises an oriented fiber membrane, a non-woven supporting membrane and a non-woven fiber membrane which are sequentially stacked. The nanofiber composite membrane provided by the invention can realize step-by-step and slow degradation matched with a nerve repair process through different degradation speeds and performances of different materials, and the nanofiber composite membrane presents different micro-pore structures at different time stages; the requirements on tissues and nutrient substances in each stage of nerve repair can be met, and scar tissues cannot be formed at the nerve anastomosis broken end during use.

Description

Technical Field

[0001] The present invention belongs to the technical field of medical materials, and particularly relates to a nanofiber composite membrane, a preparation method thereof and an application thereof. Background Art

[0002] Peripheral nerve injury is mostly caused by severe trauma. The loss of motor function in patients even causes muscle paralysis, bringing great pain to patients and their families, and also imposing a heavy medical burden on society. Clinically, for short-distance nerve rupture injuries less than 5 millimeters, the two ends of the severed nerve can generally be directly anastomosed with sutures. For nerve defects about 1 centimeter in length, the direct suture has too much tension, and an implant needs to be sewn in to reduce the suture tension and assist nerve growth. Previously, autologous nerve transplantation has always been regarded as the "gold standard" for nerve injury repair materials, and many previous studies have reported its effectiveness in promoting nerve fiber repair. However, autologous nerve transplantation has a fundamental defect in that it will cause potential functional loss of the donor site because it intercepts nerve tissue at the donor site; and autologous nerve tissue generally has a relatively large thickness, and after implantation, it is easy to cause obstruction of the formation of new blood vessels in the injured nerve. The original Schwann cells in the autologous nerve tissue have reduced activity or even die due to insufficient blood supply, losing the nerve repair function; in addition, scar tissue is easily formed at the nerve anastomosis stump, and there is a lack of a relatively closed space that is not interfered by other tissues during the nerve repair process, resulting in poor repair effects. In view of the fact that autologous nerve transplantation cannot meet the current clinical and market demands, with the breakthrough progress in the field of biomaterials in recent years, the translational research field of nerve repair has gradually focused on materials with good biocompatibility that can effectively provide a barrier effect and promote the repair of damaged nerves. The components of existing nerve repair products are mainly divided into animal-derived and biodegradable polymer materials. Animal-derived materials will cause tissue rejection reactions, and the degradation period cannot be regulated; biodegradable polymer materials have no such risks, and the degradation period can be regulated. Therefore, biodegradable polymer materials are expected to become the future development direction in this field.

[0003] An ideal nerve repair material can maximize the simulation of the in-vivo growth environment, provide a good space, mechanical properties, nutrients, etc. for nerve repair, and it should have the following characteristics: ① stable mechanical properties; ② good tissue compatibility, without causing an immune response in the body; ③ the nerve regeneration rate matches the material degradation rate; ④ good physical properties, capable of adapting to the growth of new axons; ⑤ having a certain tissue permeability, capable of absorbing essential substances such as oxygen and nutrients; ⑥ capable of preventing the invasion of fibrous tissue and maintaining the secretion of trophic factors; ⑦ being convenient for processing, shaping, aseptic disinfection, long-term storage and transportation.

[0004] Currently, the commercially available nerve repair products using degradable polymer materials at home and abroad are basically single-component, or a combination of animal-derived and single polymer components, which do not meet the requirement that the degradation rate of the ideal nerve repair material matches the nerve regeneration rate. Therefore, it is necessary to design a fiber membrane with a degradation rate matching the nerve regeneration rate. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a nanofiber composite membrane, its preparation method and application. By designing the structure and materials of the nanofiber composite membrane, the nanofiber composite membrane has a microscopic pore structure, controllable fiber morphology, and the material degradation rate matches the nerve regeneration rate, and no scar tissue will form at the nerve anastomosis stump during use.

[0006] To achieve this purpose, the present invention adopts the following technical solutions:

[0007] In the first aspect, the present invention provides a nanofiber composite membrane, which includes an oriented fiber membrane, a non-woven support membrane and a non-woven fiber membrane arranged in layers in sequence; the material of the fibers in the oriented fiber membrane includes a first degradable polymer material and optionally a second degradable polymer material; the non-woven support membrane is composed of a first fiber and a second fiber; the non-woven fiber membrane is composed of a third fiber and a fourth fiber; the materials of the first fiber and the third fiber each independently include a first degradable polymer material and optionally a second degradable polymer material; the materials of the second fiber and the fourth fiber each independently include a third degradable polymer material and optionally a second degradable polymer material; the first degradable polymer material each independently includes any one or at least two combinations of lactide-caprolactone copolymer, polycaprolactone, polylactic acid or polyglycolic acid-caprolactone copolymer; the second degradable polymer material each independently includes polyethylene glycol-lactic acid block copolymer and / or polyethylene glycol; the third degradable polymer material each independently includes any one or at least two combinations of poly(lactic-co-glycolic acid), poly(DL-lactide-glycolide) or poly(p-dioxanone); at least one of the oriented fiber membrane, the non-woven support membrane and the non-woven fiber membrane contains the second degradable polymer material.

[0008] The nanofiber composite membrane provided by the present invention includes an oriented fiber membrane, a non-woven support membrane and a non-woven fiber membrane arranged in layers in sequence, wherein the oriented fiber membrane is in direct contact with the nerve and plays a role in inducing nerve growth; the non-woven fiber membrane is in contact with the surrounding tissues and plays a role in providing a microscopic pore structure; the non-woven support membrane is a connecting layer between the oriented fiber membrane and the non-woven fiber membrane, which can enhance the mechanical strength of the nanofiber composite membrane.

[0009] The nanofiber composite membrane provided by the present invention can achieve a gradual and slow degradation that matches the nerve repair process through the different degradation rates and properties of different materials. Moreover, the nanofiber composite membrane presents different microscopic pore structures at different time stages, which can meet the requirements of various stages of nerve repair for tissues and nutrients. In the nanofiber composite membrane provided by the present invention, the degradation period of the second degradable polymer material and the third degradable polymer material is about 3 to 4 months. During this stage, the edema and inflammatory reactions of the repaired nerve and the surrounding tissues gradually subside, and the tissue gradually transitions from an inflammatory state to a proliferative state. As the initial regeneration of nerve axons is basically completed, the second degradable polymer material and the third degradable polymer material are also basically degraded. During this period, the degradation products can be slowly released, and there will be no problem of disintegration and fragmentation causing local irritation. At 4 to 6 months after injury, the third degradable polymer material and the second degradable polymer material are basically completely degraded, and the entire nanofiber composite membrane tends to soften and gradually transitions to a state that can provide a certain physical support without irritating the affected tissue. During this process, the porosity of the nanofiber composite membrane also gradually increases, which not only makes the penetration and exchange of various nutrients more sufficient, but also enables macrophages to pass through more easily, accelerating the clearance of tissue debris left by previous injuries, etc., and further promoting repair. The degradation period of the first degradable polymer material is relatively long, reaching more than one and a half years. The slow degradation of the fibers containing the first degradable polymer material provides the support required during the repair period to ensure that the nerve axons fully extend to the distal end and the neurilemma is fully repaired.

[0010] In the present invention, the first degradable polymer materials in the oriented fiber membrane, the non-woven support membrane, and the non-woven fiber membrane can be the same or different from each other; the second degradable polymer materials in the oriented fiber membrane, the non-woven support membrane, and the non-woven fiber membrane can be the same or different; the third degradable polymer materials in the non-woven support membrane and the non-woven fiber membrane can be the same or different.

[0011] The following are the preferred technical solutions of the present invention, but do not limit the technical solutions provided by the present invention. Through the following preferred technical solutions, the objectives and beneficial effects of the present invention can be better achieved.

[0012] As a preferred technical solution, the thickness of the oriented fiber membrane is 15 - 35 μm, and can be, for example, 16 μm, 18 μm, 20 μm, 22 μm, 24 μm, 26 μm, 28 μm, 30 μm, 32 μm, 34 μm, etc.

[0013] Preferably, the orientation degree of the oriented fiber membrane is 75 - 95%, and can be, for example, 76%, 78%, 80%, 82%, 84%, 86%, 88%, 90%, 92%, 94%, etc.

[0014] Preferably, the diameter of the fibers in the oriented fiber membrane is 500 - 6000 nm, for example, it can be 1000 nm, 1500 nm, 2000 nm, 2500 nm, 3000 nm, 3500 nm, 4000 nm, 4500 nm, 5000 nm, 5500 nm, etc.

[0015] Preferably, the mass percentage content of the second degradable polymer material in the oriented fiber membrane is ≤ 40%, for example, it can be 0, 1%, 2%, 5%, 8%, 10%, 12%, 15%, 18%, 20%, 22%, 25%, 28%, 30%, 32%, 35%, 38%, etc.

[0016] Preferably, the thickness of the non - woven support membrane is 30 - 50 μm, for example, it can be 32 μm, 34 μm, 36 μm, 38 μm, 40 μm, 42 μm, 44 μm, 46 μm, 48 μm, etc.

[0017] Preferably, the pore size of the non - woven support membrane is 5 - 30 μm, for example, it can be 6 μm, 10 μm, 14 μm, 18 μm, 22 μm, 26 μm, 30 μm, etc.

[0018] Preferably, the diameters of the first fiber and the second fiber are each independently 500 - 6000 nm, for example, it can be 1000 nm, 1500 nm, 2000 nm, 2500 nm, 3000 nm, 3500 nm, 4000 nm, 4500 nm, 5000 nm, 5500 nm, etc.

[0019] Preferably, the mass percentage content of the second degradable polymer material in the first fiber is ≤ 40%, for example, it can be 0, 1%, 2%, 5%, 8%, 10%, 12%, 15%, 18%, 20%, 22%, 25%, 28%, 30%, 32%, 35%, 38%, etc.

[0020] Preferably, the mass percentage content of the second degradable polymer material in the second fiber is ≤ 40%, for example, it can be 0, 1%, 2%, 5%, 8%, 10%, 12%, 15%, 18%, 20%, 22%, 25%, 28%, 30%, 32%, 35%, 38%, etc.

[0021] Preferably, the thickness of the non - woven fiber membrane is 70 - 120 μm, for example, it can be 75 μm, 80 μm, 85 μm, 90 μm, 95 μm, 100 μm, 105 μm, 110 μm, 115 μm, etc.

[0022] Preferably, the pore size of the non-woven fiber membrane is 10-30 μm, for example, it can be 12 μm, 14 μm, 16 μm, 18 μm, 20 μm, 22 μm, 24 μm, 26 μm, 28 μm, etc.

[0023] Preferably, the diameters of the third fiber and the fourth fiber are each independently 500-6000 nm, for example, they can be 1000 nm, 1500 nm, 2000 nm, 2500 nm, 3000 nm, 3500 nm, 4000 nm, 4500 nm, 5000 nm, 5500 nm, etc.

[0024] Preferably, the mass percentage content of the second biodegradable polymer material in the third fiber is ≤40%, for example, it can be 0, 1%, 2%, 5%, 8%, 10%, 12%, 15%, 18%, 20%, 22%, 25%, 28%, 30%, 32%, 35%, 38%, etc.

[0025] Preferably, the mass percentage content of the second biodegradable polymer material in the fourth fiber is ≤40%, for example, it can be 0, 1%, 2%, 5%, 8%, 10%, 12%, 15%, 18%, 20%, 22%, 25%, 28%, 30%, 32%, 35%, 38%, etc.

[0026] Preferably, the material of the fibers in the oriented fiber membrane includes a combination of a first biodegradable polymer material and a second biodegradable polymer material.

[0027] Preferably, the materials of the first fiber and the third fiber include a combination of a first biodegradable polymer material and a second biodegradable polymer material.

[0028] Preferably, the materials of the second fiber and the fourth fiber include a combination of a third biodegradable polymer material and a second biodegradable polymer material.

[0029] Preferably, the first biodegradable polymer materials in the oriented fiber membrane, the non-woven support membrane and the non-woven fiber membrane are all lactide-caprolactone copolymers.

[0030] Preferably, the weight-average molecular weight of the lactide-caprolactone copolymer is 60000-150000 (for example, 62000, 65000, 68000, 70000, 72000, 75000, 78000, 80000, 82000, 85000, 88000, 90000, 92000, 95000, 98000, 100000, 110000, 120000, 130000, 140000, etc.), and more preferably 75000-85000.

[0031] Preferably, the molar ratio of lactide units to caprolactone units in the lactide-caprolactone copolymer is (2 - 2.8):1 (such as 2.05:1, 2.1:1, 2.15:1, 2.2:1, 2.25:1, 2.3:1, 2.35:1, 2.4:1, 2.45:1, 2.5:1, 2.55:1, 2.6:1, 2.65:1, 2.7:1, 2.75:1, etc.), and more preferably (2 - 2.5):1.

[0032] Preferably, the third biodegradable polymer material in the non-woven support film and the non-woven fiber film is poly(lactic-co-glycolic acid).

[0033] Preferably, the weight-average molecular weight of the poly(lactic-co-glycolic acid) is 50000 - 100000 (such as 52000, 55000, 58000, 60000, 62000, 65000, 68000, 70000, 72000, 75000, 78000, 80000, 82000, 85000, 88000, 90000, 92000, 95000, 98000, etc.), and more preferably 70000 - 80000.

[0034] Preferably, the molar ratio of lactide units to glycolide units in the poly(lactic-co-glycolic acid) is (2.7 - 3.4):1 (such as 2.75:1, 2.8:1, 2.85:1, 2.9:1, 2.95:1, 3:1, 3.05:1, 3.1:1, 3.15:1, 3.2:1, 3.25:1, 3.3:1, 3.35:1, etc.), and more preferably (2.9 - 3.1):1.

[0035] Preferably, the poly(ethylene glycol-block-lactic acid) copolymer is contained in the oriented fiber film, the first fiber, the second fiber, the third fiber, and the fourth fiber.

[0036] Preferably, the weight-average molecular weight of the poly(ethylene glycol-block-lactic acid) copolymer is 70000 - 90000, and can be, for example, 72000, 75000, 78000, 81000, 84000, 87000, 90000, etc.

[0037] Preferably, the molar ratio of lactide units to ethylene glycol units in the poly(ethylene glycol-block-lactic acid) copolymer is (0.6 - 1.5):1 (such as 0.65:1, 0.7:1, 0.75:1, 0.8:1, 0.85:1, 0.9:1, 0.95:1, 1:1, 1.05:1, 1.1:1, 1.15:1, 1.2:1, 1.25:1, 1.3:1, 1.35:1, 1.4:1, 1.45:1, etc.), and more preferably (0.65 - 1.2):1.

[0038] Preferably, the ratio of the total mass of the first degradable polymer material to the total mass of the second degradable polymer material in the nanofiber composite membrane is (1.6 - 3):1, and can be, for example, 1.7:1, 1.8:1, 1.9:1, 2:1, 2.1:1, 2.2:1, 2.3:1, 2.4:1, 2.5:1, 2.6:1, 2.7:1, 2.8:1, 2.9:1, etc.

[0039] Preferably, the ratio of the total mass of the third degradable polymer material to the total mass of the second degradable polymer material in the nanofiber composite membrane is (2.6 - 4):1, and can be, for example, 2.7:1, 2.8:1, 2.9:1, 3:1, 3.1:1, 3.2:1, 3.3:1, 3.4:1, 3.5:1, 3.6:1, 3.7:1, 3.8:1, 3.9:1, etc.

[0040] In a second aspect, the present invention provides a method for preparing the nanofiber composite membrane as described in the first aspect, and the preparation method includes the following steps:

[0041] (1) Mix the first degradable polymer material, optionally the second degradable polymer material, and a first solvent to obtain an electrospinning stock solution A; the electrospinning stock solution A is divided into a first electrospinning stock solution A, a second electrospinning stock solution A, and a third electrospinning stock solution A;

[0042] Mix the third degradable polymer material, optionally the second degradable polymer material, and a second solvent to obtain an electrospinning stock solution B; the electrospinning stock solution B is divided into a first electrospinning stock solution B and a second electrospinning stock solution B;

[0043] (2) Perform electrospinning on the first electrospinning stock solution A to obtain an oriented fiber membrane;

[0044] (3) Perform electrospinning on the second electrospinning stock solution A and the first electrospinning stock solution B respectively, and cover the formed fibers on the oriented fiber membrane to obtain a non-woven support membrane;

[0045] (4) Perform electrospinning on the third electrospinning stock solution A and the second electrospinning stock solution B respectively, and cover the formed fibers on the non-woven support membrane to obtain the nanofiber composite membrane.

[0046] Preferably, each of the first solvent and the second solvent independently includes any one or a combination of at least two of N,N-dimethylformamide, acetone, hexafluoroisopropanol, or dichloromethane.

[0047] Preferably, the mass percentage content of the first solvent in the first electrospinning stock solution A, the second electrospinning stock solution A, and the third electrospinning stock solution A is independently 10-80%, for example, it can be 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, etc.

[0048] Preferably, the mass percentage content of the second solvent in the first electrospinning stock solution B and the second electrospinning stock solution B is independently 10-60%, for example, it can be 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, etc.

[0049] In the present invention, the types and dosages of the first biodegradable polymer material in the first electrospinning stock solution A, the second electrospinning stock solution A, and the third electrospinning stock solution A can be the same or different from each other, the types and dosages of the second biodegradable polymer material can be the same or different from each other, and the types and dosages of the first solvent can be the same or different from each other.

[0050] In the present invention, the types and dosages of the third biodegradable polymer material in the first electrospinning stock solution B and the second electrospinning stock solution B can be the same or different, the types and dosages of the second biodegradable polymer material can be the same or different, and the types and dosages of the second solvent can be the same or different.

[0051] In the present invention, the electrospinning stock solution A can be evenly divided into three parts, namely the first electrospinning stock solution A, the second electrospinning stock solution A, and the third electrospinning stock solution A, that is, the compositions and masses of the first electrospinning stock solution A, the second electrospinning stock solution A, and the third electrospinning stock solution A are the same.

[0052] In the present invention, the electrospinning stock solution B can be evenly divided into two parts, namely the first electrospinning stock solution B and the second electrospinning stock solution B, that is, the compositions and masses of the first electrospinning stock solution B and the second electrospinning stock solution B are the same.

[0053] Preferably, in the electrospinning of step (2), the injection rate of the first electrospinning stock solution A is 15-25 μL / min (such as 16 μL / min, 17 μL / min, 18 μL / min, 19 μL / min, 20 μL / min, 21 μL / min, 22 μL / min, 23 μL / min, 24 μL / min, etc.), the applied voltage is 15-35 kV (such as 16 kV, 17 kV, 18 kV, 19 kV, 20 kV, 21 kV, 22 kV, 23 kV, 24 kV, 25 kV, 26 kV, 27 kV, 28 kV, 29 kV, 30 kV, 31 kV, 32 kV, 33 kV, 34 kV, etc.), and the receiving distance is 25-35 cm (such as 25.5 cm, 26 cm, 26.5 cm, 27 cm, 27.5 cm, 28 cm, 28.5 cm, 29 cm, 29.5 cm, 30 cm, 30.5 cm, 31 cm, 31.5 cm, 32 cm, 32.5 cm, 33 cm, 33.5 cm, 34 cm, 34.5 cm, etc.); the spinning is collected by a roller, and the rotation speed of the roller is 2500-4500 r / min (such as 2600 r / min, 2800 r / min, 3000 r / min, 3200 r / min, 3400 r / min, 3600 r / min, 3800 r / min, 4000 r / min, 4200 r / min, 4400 r / min, etc.).

[0054] Preferably, the time of the electrospinning in step (2) is 15-30 min, for example, it can be 16 min, 17 min, 18 min, 19 min, 20 min, 21 min, 22 min, 23 min, 24 min, 25 min, 26 min, 27 min, 28 min, 29 min, etc.

[0055] Preferably, in the electrospinning of step (3), the injection speed of the second electrospinning solution A and the first electrospinning solution B is 25-45 μL / min (for example, 26 μL / min, 27 μL / min, 28 μL / min, 29 μL / min, 30 μL / min, 31 μL / min, 32 μL / min, 33 μL / min, 34 μL / min, 35 μL / min, 36 μL / min, 37 μL / min, 38 μL / min, 39 μL / min, 40 μL / min, 41 μL / min, 42 μL / min, 43 μL / min, 44 μL / min, etc.), and The load voltage is 25-35kV (for example, 26kV, 27kV, 28kV, 29kV, 30kV, 31kV, 32kV, 33kV, 34kV, etc.), and the receiving distance is 15-25cm (for example, 16cm, 17cm, 18cm, 19cm, 20cm, 21cm, 22cm, 23cm, 24cm, etc.); the spinning is collected by a drum, and the rotation speed of the drum is 50-500r / min (for example, 100r / min, 150r / min, 200r / min, 250r / min, 300r / min, 350r / min, 400r / min, 450r / min, etc.).

[0056] Preferably, the electrospinning time in step (3) is 5-10 min, for example, it can be 5.5 min, 6 min, 6.5 min, 7 min, 7.5 min, 8 min, 8.5 min, 9 min, 9.5 min, etc.

[0057] Preferably, the electrospinning in step (3) is carried out by an electrospinning device containing 8-12 (e.g., 8, 10, 12) nozzles; after the second electrospinning stock solution A and the first electrospinning stock solution B are alternately placed in each of the nozzles, the electrospinning in step (3) is carried out.

[0058] In the present invention, the second electrospinning stock solution A and the first electrospinning stock solution B are placed alternately in each of the nozzles, which means that the electrospinning stock solution is placed in each nozzle in a repeating order of the second electrospinning stock solution A and the first electrospinning stock solution B; it should be noted that the electrospinning stock solution can also be placed in each nozzle in a repeating order of the second electrospinning stock solution A, the second electrospinning stock solution A, and the first electrospinning stock solution B, as long as the second electrospinning stock solution A and the first electrospinning stock solution B are staggered.

[0059] Preferably, in the electrospinning of step (4), the injection speed of the third electrospinning solution A and the second electrospinning solution B is 20-45 μL / min (for example, 21 μL / min, 22 μL / min, 23 μL / min, 24 μL / min, 25 μL / min, 26 μL / min, 27 μL / min, 28 μL / min, 29 μL / min, 30 μL / min, 31 μL / min, 32 μL / min, 33 μL / min, 34 μL / min, 35 μL / min, 36 μL / min, 37 μL / min, 38 μL / min, 39 μL / min, 40 μL / min, 41 μL / min, 42 μL / min, 43 μL / min, 44 μL / min, etc.), and the loading voltage is 25-35 kV ( For example, 26kV, 27kV, 28kV, 29kV, 30kV, 31kV, 32kV, 33kV, 34kV, etc.), the receiving distance is 25-35cm (for example, 25.5cm, 26cm, 26.5cm, 27cm, 27.5cm, 28cm, 28.5cm, 29cm, 29.5cm, 30cm, 30.5cm, 31cm, 31.5cm, 32cm, 32.5cm, 33cm, 33.5cm, 34cm, 34.5cm, etc.); the spinning is collected by a drum, and the rotation speed of the drum is 50-500r / min (for example, 100r / min, 150r / min, 200r / min, 250r / min, 300r / min, 350r / min, 400r / min, 450r / min, etc.).

[0060] Preferably, the electrospinning time in step (4) is 40-60 min, for example, it can be 42 min, 44 min, 46 min, 48 min, 50 min, 52 min, 54 min, 56 min, 58 min, etc.

[0061] Preferably, the electrospinning in step (4) is carried out by an electrospinning device containing 8-12 (e.g., 8, 10, 12) nozzles; after the third electrospinning stock solution A and the second electrospinning stock solution B are alternately placed in each of the nozzles, the electrospinning in step (4) is carried out.

[0062] In the present invention, the third electrospinning stock solution A and the second electrospinning stock solution B are placed alternately in each of the nozzles, which means that the electrospinning stock solution is placed in each nozzle in a repeating order of the third electrospinning stock solution A and the second electrospinning stock solution B; it should be noted that the electrospinning stock solution can also be placed in each nozzle in a repeating order of the third electrospinning stock solution A, the third electrospinning stock solution A, and the second electrospinning stock solution B, as long as the third electrospinning stock solution A and the second electrospinning stock solution B are staggered.

[0063] Preferably, after the electrospinning in step (4), a heat setting step is further included.

[0064] Preferably, the temperature of the heat setting is 35 - 55 °C, for example, it can be 36 °C, 38 °C, 40 °C, 42 °C, 44 °C, 46 °C, 48 °C, 50 °C, 52 °C, 54 °C, etc.

[0065] Preferably, the time of the heat setting is 20 - 60 min, for example, it can be 22 min, 24 min, 26 min, 28 min, 30 min, 32 min, 34 min, 36 min, 38 min, 40 min, 42 min, 44 min, 46 min, 48 min, 50 min, 52 min, 54 min, 56 min, 58 min, etc.

[0066] In a third aspect, the present invention provides an application of the nanofiber composite membrane as described in the first aspect in nerve repair materials.

[0067] Compared with the prior art, the present invention has the following beneficial effects:

[0068] The nanofiber composite membrane provided by the present invention, through the design of the structure and the selection of materials with different degradation rates, enables the nanofiber composite membrane to have a microscopic pore structure, controllable fiber morphology, and through the different degradation rates and properties of different materials, it can achieve a step-by-step and slow degradation that matches the nerve repair process. Moreover, the nanofiber composite membrane presents different microscopic pore structures at different time stages, which can meet the requirements of each stage of nerve repair for tissues and nutrients, and no scar tissue will be formed at the nerve anastomosis stump during use. Description of the Drawings

[0069] Figure 1 It is the SEM image of the oriented fiber membrane of the nanofiber composite membrane provided in Example 1 after 1 week of degradation;

[0070] Figure 2 It is the SEM image of the non-woven fiber membrane of the nanofiber composite membrane provided in Example 1 after 1 week of degradation;

[0071] Figure 3 It is the SEM image of the oriented fiber membrane of the nanofiber composite membrane provided in Example 1 after 12 weeks of degradation;

[0072] Figure 4 It is the SEM image of the non-woven fiber membrane of the nanofiber composite membrane provided in Example 1 after 12 weeks of degradation;

[0073] Figure 5 It is the SEM image of the oriented fiber membrane of the nanofiber composite membrane provided in Example 1 after 26 weeks of degradation;

[0074] Figure 6 It is the SEM image of the non-woven fiber membrane after 26 weeks of degradation of the nanofiber composite membrane provided in Example 1;

[0075] Figure 7 It is the SEM image of the oriented fiber membrane after 40 weeks of degradation of the nanofiber composite membrane provided in Example 1;

[0076] Figure 8 It is the SEM image of the non-woven fiber membrane after 40 weeks of degradation of the nanofiber composite membrane provided in Example 1;

[0077] Figure 9 It is the SEM image of the non-woven fiber membrane after 1 week of degradation of the nanofiber composite membrane provided in Example 2;

[0078] Figure 10 It is the SEM image of the non-woven fiber membrane after 12 weeks of degradation of the nanofiber composite membrane provided in Example 2;

[0079] Figure 11 It is the SEM image of the non-woven fiber membrane after 26 weeks of degradation of the nanofiber composite membrane provided in Example 2;

[0080] Figure 12 It is the SEM image of the non-woven fiber membrane after 40 weeks of degradation of the nanofiber composite membrane provided in Example 2;

[0081] Figure 13 It is the SEM image of the non-woven fiber membrane after 1 week of degradation of the nanofiber composite membrane provided in Example 3;

[0082] Figure 14 It is the SEM image of the non-woven fiber membrane after 12 weeks of degradation of the nanofiber composite membrane provided in Example 3;

[0083] Figure 15 It is the SEM image of the non-woven fiber membrane after 26 weeks of degradation of the nanofiber composite membrane provided in Example 3;

[0084] Figure 16 It is the SEM image of the non-woven fiber membrane after 40 weeks of degradation of the nanofiber composite membrane provided in Example 3;

[0085] Figure 17 It is the SEM image of the non-woven fiber membrane after 1 week of degradation of the nanofiber composite membrane provided in Example 4;

[0086] Figure 18 It is the SEM image of the non-woven fiber membrane after 12 weeks of degradation of the nanofiber composite membrane provided in Example 4;

[0087] Figure 19 It is the SEM image of the non-woven fiber membrane after 26 weeks of degradation of the nanofiber composite membrane provided in Example 4;

[0088] Figure 20 SEM image of the non-woven fiber membrane after 40 weeks of degradation of the nanofiber composite membrane provided in Example 4;

[0089] Figure 21 SEM image of the non-woven fiber membrane after 1 week of degradation of the nanofiber composite membrane provided in Comparative Example 1;

[0090] Figure 22 Cytoskeleton staining image of mouse adrenal pheochromocytoma cells on the oriented fiber membrane in the nanofiber composite membrane provided in Example 1;

[0091] Figure 23 DAPI staining image of mouse adrenal pheochromocytoma cells on the oriented fiber membrane in the nanofiber composite membrane provided in Example 1;

[0092] Figure 24 FITC-labeled phalloidin staining image of mouse adrenal pheochromocytoma cells on the oriented fiber membrane in the nanofiber composite membrane provided in Example 1;

[0093] Figure 25 Cytoskeleton staining image of mouse Schwann cells on the oriented fiber membrane in the nanofiber composite membrane provided in Example 1;

[0094] Figure 26 DAPI staining image of mouse Schwann cells on the oriented fiber membrane in the nanofiber composite membrane provided in Example 1;

[0095] Figure 27 Rhodamine red-labeled phalloidin staining image of mouse Schwann cells on the oriented fiber membrane in the nanofiber composite membrane provided in Example 1;

[0096] Figure 28 Cytoskeleton staining image of mouse embryonic fibroblasts on the non-woven fiber membrane in the nanofiber composite membrane provided in Example 1;

[0097] Figure 29 DAPI staining image of mouse embryonic fibroblasts on the non-woven fiber membrane in the nanofiber composite membrane provided in Example 1;

[0098] Figure 30 FITC-labeled phalloidin staining image of mouse embryonic fibroblasts on the non-woven fiber membrane in the nanofiber composite membrane provided in Example 1. Detailed implementation manners

[0099] The technical solutions of the present invention will be further described below in conjunction with the accompanying drawings and through specific implementation manners. Those skilled in the art should understand that the described embodiments are only for helping to understand the present invention and should not be regarded as specific limitations on the present invention.

[0100] The sources of some components in the following examples and comparative examples are as follows:

[0101] (1) Lactide-caprolactone copolymer (PLCL): purchased from Merck KGaA, Darmstadt, Germany, with a weight average molecular weight of 80,000 and a molar ratio of lactide unit to caprolactone unit of 67:33;

[0102] (2) Polyethylene glycol-lactic acid block copolymer (PELA): purchased from Xi'an Qiyue Biotechnology Co., Ltd., with a weight average molecular weight of 70,000 and a molar ratio of lactide unit to ethylene glycol unit of 40:60;

[0103] (3) Poly(lactic acid-co-glycolic acid) (PLGA): purchased from Evonik Specialty Chemicals (Shanghai) Co., Ltd., with a weight average molecular weight of 70,000 and a molar ratio of lactide units to glycolide units of 75:25;

[0104] (4) Polycaprolactone (PCL): purchased from Evonik Specialty Chemicals (Shanghai) Co., Ltd., with a weight average molecular weight of 80,000;

[0105] (5) Poly(DL-lactide-glycolide) (PDLG): purchased from Evonik Specialty Chemicals (Shanghai) Co., Ltd., with a weight average molecular weight of 80,000 and a molar ratio of lactide units to glycolide units of 73:27.

[0106] Example 1

[0107] A nanofiber composite membrane, the nanofiber composite membrane comprising an oriented fiber membrane, a non-woven support membrane and a non-woven fiber membrane stacked in sequence;

[0108] The preparation method of the nanofiber composite membrane comprises the following steps:

[0109] (1) 25 g of PLCL and PELA were dissolved in a mixed solvent of hexafluoroisopropanol and dichloromethane (the mass ratio of hexafluoroisopropanol and dichloromethane was 20:80) at a mass ratio of 9:1, and after uniform stirring, an electrospinning stock solution A was obtained; the mass percentage of PLCL in the electrospinning stock solution A was 25%; the electrospinning stock solution A was divided into three parts, namely, a first electrospinning stock solution A, a second electrospinning stock solution A and a third electrospinning stock solution A; the mass ratio of the first electrospinning stock solution A, the second electrospinning stock solution A and the third electrospinning stock solution A was 1:1:1;

[0110] Dissolve 50 g of PLGA and PELA in a mixed solvent of N,N-dimethylformamide and acetone according to a mass ratio of 8:2 (the mass ratio of N,N-dimethylformamide to acetone is 50:50). After uniform stirring, electrospinning stock solution B is obtained; the mass percentage content of PLGA in the electrospinning stock solution B is 50%; divide the electrospinning stock solution B into two parts, namely the first electrospinning stock solution B and the second electrospinning stock solution B; the mass ratio of the first electrospinning stock solution B to the second electrospinning stock solution B is 1:1;

[0111] (2) Inject the first electrospinning stock solution A into the syringe of the electrospinning device, and perform electrospinning under the action of a propulsion pump. Adjust the injection speed to 15 μL / min, the applied voltage to 20 kV, and the receiving distance to 30 cm; the formed fibers are ejected from the spinneret of the electrospinning device, and the collection method uses a high-speed roller with a roller speed of 3000 r / min. Electrospin for 15 min to obtain the oriented fiber membrane with a fiber orientation degree of 85%, a thickness of 20 μm, and a fiber diameter of 800 nm;

[0112] (3) Place the second electrospinning stock solution A in 5 a nozzles, and place the first electrospinning stock solution B in 5 b nozzles, and the a and b nozzles are arranged alternately; perform electrospinning on the second electrospinning stock solution A and the first electrospinning stock solution B, with an injection speed of 30 μL / min, an applied voltage of 25 kV, and a receiving distance of 15 cm. The collection method uses a low-speed roller with a roller speed of 200 r / min. Electrospin for 5 min, and the formed fibers cover the oriented fiber membrane to obtain the non-woven support membrane with a thickness of 35 μm, a pore size of 12 μm, and a fiber diameter of 600 nm;

[0113] (4) Place the third electrospinning stock solution A in 5 a nozzles, and place the second electrospinning stock solution B in 5 b nozzles, and the a and b nozzles are arranged alternately; perform electrospinning on the third electrospinning stock solution A and the second electrospinning stock solution B, with an injection speed of 25 μL / min, an applied voltage of 25 kV, and a receiving distance of 30 cm. The collection method uses a low-speed roller with a roller speed of 100 r / min. Electrospin for 60 min, and the formed fibers cover the non-woven support membrane to obtain the non-woven fiber membrane with a thickness of 100 μm, a pore size of 16 μm, and a fiber diameter of 600 nm; after the above composite membrane is unloaded from the roller, it is fixed around on a glass plate and then covered with a glass plate for heat setting. The heat setting temperature is 45 °C and the time is 25 min to obtain the nanofiber composite membrane.

[0114] Example 2

[0115] A nanofiber composite membrane, which includes an oriented fiber membrane, a non-woven support membrane, and a non-woven fiber membrane that are sequentially stacked;

[0116] The preparation method of the nanofiber composite membrane comprises the following steps:

[0117] (1) Dissolve 25 g of PCL in a mixed solvent of hexafluoroisopropanol and dichloromethane (the mass ratio of hexafluoroisopropanol to dichloromethane is 30:70). After uniform stirring, obtain electrospinning stock solution A; the mass percentage content of PCL in the electrospinning stock solution A is 25%; divide the electrospinning stock solution A into three parts, namely the first electrospinning stock solution A, the second electrospinning stock solution A, and the third electrospinning stock solution A; the mass ratio of the first electrospinning stock solution A, the second electrospinning stock solution A, and the third electrospinning stock solution A is 1:1:1;

[0118] Dissolve 50 g of PDLG and PELA in a mixed solvent of N,N-dimethylformamide and acetone (the mass ratio of N,N-dimethylformamide to acetone is 50:50) according to a mass ratio of 4:1. After uniform stirring, obtain electrospinning stock solution B; the mass percentage content of PDLG in the electrospinning stock solution B is 50%; divide the electrospinning stock solution B into two parts, namely the first electrospinning stock solution B and the second electrospinning stock solution B; the mass ratio of the first electrospinning stock solution B and the second electrospinning stock solution B is 1:1;

[0119] (2) Inject the first electrospinning stock solution A into the syringe of the electrospinning device. Under the action of a propulsion pump, carry out electrospinning. Adjust the injection speed to 16 μL / min, the applied voltage to 25 kV, and the receiving distance to 35 cm; the formed spinning is ejected from the spinneret of the electrospinning device, and the collection method is a high-speed roller with a roller speed of 3500 r / min. Electrospin for 18 min to obtain the oriented fiber membrane with an orientation degree of 80% for the fibers, a thickness of 24 μm, and a fiber diameter of 1000 nm;

[0120] (3) Place the second electrospinning stock solution A in 5 a nozzles, and place the first electrospinning stock solution B in 5 b nozzles, and the a and b nozzles are arranged alternately; carry out electrospinning on the second electrospinning stock solution A and the first electrospinning stock solution B, with an injection speed of 35 μL / min, an applied voltage of 30 kV, and a receiving distance of 20 cm. The collection method is a low-speed roller with a roller speed of 300 r / min. Electrospin for 10 min, and the formed spinning covers the oriented fiber membrane to obtain the non-woven support membrane with a thickness of 45 μm, a pore diameter of 16 μm, and a fiber diameter of 800 nm;

[0121] (4) Place the third electrospinning stock solution A in 5 a nozzles, and place the second electrospinning stock solution B in 5 b nozzles, with the a and b nozzles arranged alternately; perform electrospinning on the third electrospinning stock solution A and the second electrospinning stock solution B, with an injection rate of 30 μL / min, a loading voltage of 30 kV, a receiving distance of 35 cm, and a collection method using a low-speed roller with a roller rotation speed of 300 r / min. Spin for 55 min, and cover the non-woven support membrane with the formed spun fibers to obtain the non-woven fiber membrane, which has a thickness of 120 μm, a pore size of 20 μm, and a fiber diameter of 800 nm; after the above composite membrane is unloaded from the roller, it is fixed around and then covered with a glass plate for heat setting at a heat setting temperature of 50 °C for 30 min to obtain the nanofiber composite membrane.

[0122] Example 3

[0123] A nanofiber composite membrane and a preparation method thereof, which are different from Example 1 only in that the total mass of PLCL and PELA in the electrospinning stock solution A remains unchanged, and the mass ratio of the two is 1:1, and the remaining raw materials, process parameters, and steps are the same as those in Example 1.

[0124] Example 4

[0125] A nanofiber composite membrane and a preparation method thereof, which are different from Example 1 only in that the total mass of PLGA and PELA in the electrospinning stock solution B remains unchanged, and the mass ratio of the two is 1:1, and the remaining raw materials, process parameters, and steps are the same as those in Example 1.

[0126] Comparative Example 1

[0127] A nanofiber composite membrane and a preparation method thereof, which are different from Example 1 only in that PLCL in the electrospinning stock solution A is replaced with PLGA in equal mass, and the remaining raw materials, process parameters, and steps are the same as those in Example 1.

[0128] Performance test

[0129] (1) Degradation performance

[0130] Perform in vitro degradation simulation on the nanofiber composite membrane provided in Example 1 in PBS buffer solution (pH = 7.4) at 37 °C, and take microstructural diagrams of the product at different degradation times by scanning electron microscopy (Thermo Fisher Scientific, Axia ChemiSEM). The obtained results are shown in Table 1:

[0131] Table 1

[0132]

[0133]

[0134] From Figures 1 - 8It can be seen that the oriented fiber membrane in the nanofiber composite membrane provided in Example 1 always maintains an oriented structure during different degradation periods. The non-woven fiber membrane can be gradually degraded as the degradation time increases, so that the nanofiber composite membrane presents different microscopic pore structures at different time stages, which can meet the requirements of each stage of nerve repair for tissues and nutrients.

[0135] The same in vitro degradation simulation as in Example 1 was carried out on the nanofiber composite membrane provided in Example 2, and the obtained results are as Figures 9 - 12 shown. It can be seen from Figures 9 - 12 that although the raw materials of the nanofiber composite membrane provided in Example 2 are changed, its non-woven fiber membrane is still gradually degraded as the degradation time increases, so that the nanofiber composite membrane presents different microscopic pore structures at different time stages, which can meet the requirements of each stage of nerve repair for tissues and nutrients.

[0136] The same in vitro degradation simulation as in Example 1 was carried out on the nanofiber composite membrane provided in Example 3, and the obtained results are as Figures 13 - 16 shown. It can be seen from Figures 13 - 16 that compared with Example 1, for the nanofiber composite membrane provided in Example 3, the total content of PLCL decreases, the total content of PELA increases, the non-woven fiber membrane is not significantly degraded as the degradation time increases, and the microscopic pore structure after 40 weeks of degradation is not clear.

[0137] The same in vitro degradation simulation as in Example 1 was carried out on the nanofiber composite membrane provided in Example 4, and the obtained results are as Figures 17 - 20 shown. It can be seen from Figures 17 - 20 that compared with Example 1, for the nanofiber composite membrane provided in Example 4, the total content of PLGA decreases, the total content of PELA increases, the non-woven fiber membrane is not significantly degraded in the early stage, the microscopic void structure is blurred, and the microscopic pore structure gradually becomes clear until 26 weeks later.

[0138] The same in vitro degradation simulation as in Example 1 was carried out on the nanofiber composite membrane provided in Comparative Example 1, and the obtained results are as Figure 21 shown. It can be seen from Figure 21 that compared with Example 1, the nanofiber composite membrane provided in Comparative Example 1 has no PLCL, and its non-woven fiber membrane breaks and degrades directly as the degradation time increases, which is different from the gradual degradation of the nanofiber composite membrane provided by the present invention, and it has been completely degraded after 12 weeks of degradation, and there is no microscopic pore structure.

[0139] (2) Repair effect

[0140] On the oriented fiber membrane of the nanofiber composite membrane (1.5 cm × 1.5 cm) provided in Example 1, murine adrenal pheochromocytoma cells (PC12) and murine Schwann cells (RSC-96) were cultured. Murine adrenal pheochromocytoma cells (PC12) and murine Schwann cells (RSC-96) were cultured and used as a single cell layer in disposable cell culture vessels. The cell culture was carried out in a carbon dioxide incubator at 37 °C ± 1 °C with high humidity and a CO2% set at 5%. The culture medium used for cell culture was a basal medium (RPMI 1640) containing 10% fetal bovine serum (FBS). After cell collection, the concentration was adjusted to 2×10 4 cells / mL, and 0.5 mL of cell suspension was added to each well of a 24-well plate. PC12 cells were cultured for 48 h to reach a confluence of 90%. The cells were stained with the prepared FITC-labeled phalloidin working solution and DAPI solution working solution, and then the test article and the coverslip were sealed to prepare a specimen slide for fluorescence observation under a confocal microscope. The FITC excitation / emission filter (Ex / Em = 496 / 516 nm) and DAPI excitation / emission filter (Ex / Em = 364 / 454 nm) were selected. The results are as shown in Figures 22 - 24 shown. It can be seen from Figures 22 - 24 that PC12 (which has the property of differentiating into neurons) extends long axons along the fiber orientation, better promoting axon repair, thus having the effect of promoting repair. RSC-96 cells were cultured for 48 h to reach a confluence of 90%; the cells were stained with the prepared rhodamine red-labeled phalloidin working solution and DAPI solution working solution, and then the test article and the coverslip were sealed to prepare a specimen slide for fluorescence observation under a 60-fold magnification confocal microscope. The rhodamine red excitation / emission filter (Ex / Em = 570 / 590 nm) and DAPI excitation / emission filter (Ex / Em = 364 / 454 nm) were selected. The results are as shown in Figures 25 - 27 shown. It can be seen from Figures 25 - 27 that the nanofiber composite membrane provided by the present invention can effectively guide the adhesion and arrangement of RSC-96 along the fiber orientation of the oriented fiber membrane.

[0141] (3) Protective effect on nerves

[0142] Mouse embryonic fibroblasts (NIH-3T3) were cultured on the non-woven fiber membrane of the nanofiber composite membrane (1.5 cm × 1.5 cm) provided in Example 1. Mouse embryonic fibroblasts (NIH-3T3) were cultured and used as a single cell layer in disposable cell culture vessels. The cell culture was carried out in a carbon dioxide incubator at 37 °C ± 1 °C with high humidity and a CO2% set at 5%. The culture medium used for cell culture was a basal medium (DMEM) containing 10% fetal bovine serum (FBS); in addition, 100 units / mL penicillin and 100 μg / mL streptomycin were added to the culture medium. After the cells were collected, the concentration was adjusted to 1×10 4 cells / mL, and 0.5 mL of cell suspension was added to each well of a 24-well plate. The cells were cultured for 48 h to reach a confluence of 90%. The cells were stained with the prepared FITC-labeled phalloidin working solution and the DAPI solution working solution, and then the test article and the coverslip were sealed to prepare a specimen slide for fluorescence observation under a confocal microscope. The FITC excitation / emission filter (Ex / Em = 496 / 516 nm) and the DAPI excitation / emission filter (Ex / Em = 364 / 454 nm) were selected. The results obtained were as Figures 28 - 30 shown. It can be seen from the figure that the fibroblasts showed good distribution and were presented on the surface of the non-woven fiber membrane, without forming cell aggregates or infiltrating the product, and thus would not develop into scar tissue near the nerve.

[0143] The applicant declares that the present invention uses the above embodiments to illustrate the nanofiber composite membrane of the present invention, its preparation method and application, but the present invention is not limited to the above embodiments, that is, it does not mean that the present invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, the equivalent replacement of each raw material of the product of the present invention, the addition of auxiliary components, the selection of specific methods, etc. all fall within the protection scope and the disclosure scope of the present invention.

Claims

1. A nanofiber composite membrane, characterized in that, The nanofiber composite membrane includes an oriented fiber membrane, a non-woven support membrane, and a non-woven fiber membrane that are stacked in sequence; The material of the fibers in the oriented fiber membrane includes a first biodegradable polymer material and optionally a second biodegradable polymer material; The non-woven support membrane is composed of a first fiber and a second fiber; The non-woven fiber membrane is composed of a third fiber and a fourth fiber; The materials of the first fiber and the third fiber each independently include a first biodegradable polymer material and optionally a second biodegradable polymer material; The materials of the second fiber and the fourth fiber each independently include a third biodegradable polymer material and optionally a second biodegradable polymer material; The first biodegradable polymer material each independently includes any one or a combination of at least two of lactide-caprolactone copolymer, polycaprolactone, polylactic acid, or polyglycolic acid-polycaprolactone copolymer; The second biodegradable polymer material each independently includes a polyethylene glycol-lactic acid block copolymer and / or polyethylene glycol; The third biodegradable polymer material each independently includes any one or a combination of at least two of poly(lactic-co-glycolic acid), poly(DL-lactide-glycolide), or poly(p-dioxanone); At least one of the oriented fiber membrane, the non-woven support membrane, and the non-woven fiber membrane contains the second biodegradable polymer material.

2. The nanofiber composite membrane according to claim 1, characterized in that, The thickness of the oriented fiber membrane is 15 - 35 μm; Preferably, the degree of orientation of the oriented fiber membrane is 75 - 95%; Preferably, the diameter of the fibers in the oriented fiber membrane is 500 - 6000 nm; Preferably, the mass percentage content of the second biodegradable polymer material in the oriented fiber membrane is ≤40%; 3. The nanofiber composite membrane according to claim 1 or 2, characterized in that, The thickness of the non-woven support membrane is 30 - 50 μm; Preferably, the pore size of the non-woven support membrane is 5 - 30 μm; Preferably, the diameters of the first fiber and the second fiber are each independently 500 - 6000 nm; Preferably, the mass percentage content of the second biodegradable polymer material in the first fiber is ≤40%; Preferably, the mass percentage content of the second biodegradable polymer material in the second fiber is ≤40%; 4. The nanofiber composite membrane according to any one of claims 1-3, characterized in that, The thickness of the non-woven fiber membrane is 70 - 120 μm; Preferably, the pore size of the non-woven fiber membrane is 10 - 30 μm; Preferably, the diameters of the third fiber and the fourth fiber are each independently 500 - 6000 nm; Preferably, the mass percentage content of the second biodegradable polymer material in the third fiber is ≤40%; Preferably, the mass percentage content of the second biodegradable polymer material in the fourth fiber is ≤40%; 5. The nanofiber composite membrane according to any one of claims 1-4, characterized in that, The material of the fibers in the oriented fiber membrane includes a combination of a first biodegradable polymer material and a second biodegradable polymer material; Preferably, the materials of the first fiber and the third fiber include a combination of a first biodegradable polymer material and a second biodegradable polymer material; Preferably, the materials of the second fiber and the fourth fiber include a combination of a third biodegradable polymer material and a second biodegradable polymer material; Preferably, the first biodegradable polymer material in the oriented fiber membrane, the non-woven support membrane, and the non-woven fiber membrane is lactide-caprolactone copolymer; Preferably, the weight-average molecular weight of the lactide-caprolactone copolymer is 60,000-150,000, more preferably 75,000-85,000; Preferably, the molar ratio of lactide units to caprolactone units in the lactide-caprolactone copolymer is (2-2.8):1, more preferably (2-2.5):1; Preferably, the third biodegradable polymer material in the non-woven support film and the non-woven fiber film is poly(lactic-co-glycolic acid); Preferably, the weight-average molecular weight of the poly(lactic-co-glycolic acid) is 50,000-100,000, more preferably 70,000-80,000; Preferably, the molar ratio of lactide units to glycolide units in the poly(lactic-co-glycolic acid) is (2.7-3.4):1, more preferably (2.9-3.1):1; Preferably, the poly(ethylene glycol-block-lactic acid) copolymer is contained in the oriented fiber film, the first fiber, the second fiber, the third fiber and the fourth fiber; Preferably, the weight-average molecular weight of the poly(ethylene glycol-block-lactic acid) copolymer is 70,000-90,000; Preferably, the molar ratio of lactide units to ethylene glycol units in the poly(ethylene glycol-block-lactic acid) copolymer is (0.6-1.5):1, more preferably (0.65-1.2):1; Preferably, the ratio of the total mass of the first biodegradable polymer material to the total mass of the second biodegradable polymer material in the nanofiber composite film is (1.6-3):1; Preferably, the ratio of the total mass of the third biodegradable polymer material to the total mass of the second biodegradable polymer material in the nanofiber composite film is (2.6-4):

1.

6. A method for preparing a nanofiber composite membrane according to any one of claims 1-5, characterized in that, The preparation method comprises the following steps: (1) Mix the first biodegradable polymer material, optionally the second biodegradable polymer material and the first solvent to obtain electrospinning stock solution A; the electrospinning stock solution A is divided into the first electrospinning stock solution A, the second electrospinning stock solution A and the third electrospinning stock solution A; Mix the third biodegradable polymer material, optionally the second biodegradable polymer material and the second solvent to obtain electrospinning stock solution B; the electrospinning stock solution B is divided into the first electrospinning stock solution B and the second electrospinning stock solution B; (2) Perform electrospinning on the first electrospinning stock solution A to obtain an oriented fiber film; (3) Perform electrospinning on the second electrospinning stock solution A and the first electrospinning stock solution B respectively, and cover the formed spun fibers on the oriented fiber film to obtain a non-woven support film; (4) Perform electrospinning on the third electrospinning stock solution A and the second electrospinning stock solution B respectively, and cover the formed spun fibers on the non-woven support film to obtain the nanofiber composite film.

7. The preparation method according to claim 6, characterized in that, The first solvent and the second solvent each independently comprise any one or a combination of at least two of N,N-dimethylformamide, acetone, hexafluoroisopropanol or dichloromethane; Preferably, the mass percentage content of the first solvent in the first electrospinning stock solution A, the second electrospinning stock solution A and the third electrospinning stock solution A is each independently 10-80%; Preferably, the mass percentage content of the second solvent in the first electrospinning stock solution B and the second electrospinning stock solution B is each independently 10-60%; Preferably, in the electrospinning of step (2), the injection rate of the first electrospinning stock solution A is 15-25 μL / min, the applied voltage is 15-35 kV, and the receiving distance is 25-35 cm; the spinning is collected by a roller, and the rotation speed of the roller is 2500-4500 r / min; Preferably, the electrospinning time of step (2) is 15-30 min.

8. The preparation method according to claim 6 or 7, characterized in that, In the electrospinning of step (3), the injection rates of the second electrospinning stock solution A and the first electrospinning stock solution B are 25-45 μL / min, the applied voltage is 25-35 kV, and the receiving distance is 15-25 cm; the spinning is collected by a roller, and the rotation speed of the roller is 50-500 r / min; Preferably, the electrospinning time of step (3) is 5-10 min; Preferably, the electrospinning of step (3) is carried out by an electrospinning device with 8-12 nozzles; after the second electrospinning stock solution A and the first electrospinning stock solution B are alternately placed in each nozzle, the electrospinning of step (3) is carried out; Preferably, in the electrospinning of step (4), the injection rates of the third electrospinning stock solution A and the second electrospinning stock solution B are 20-45 μL / min, the applied voltage is 25-35 kV, and the receiving distance is 25-35 cm; the spinning is collected by a roller, and the rotation speed of the roller is 50-500 r / min; Preferably, the electrospinning time of step (4) is 40-60 min; Preferably, the electrospinning of step (4) is carried out by an electrospinning device with 8-12 nozzles; after the third electrospinning stock solution A and the second electrospinning stock solution B are alternately placed in each nozzle, the electrospinning of step (4) is carried out.

9. The preparation method according to any one of claims 6-8, characterized in that, After the electrospinning of step (4) is completed, there is also a heat setting step; Preferably, the temperature of the heat setting is 35-55 °C; Preferably, the time of the heat setting is 20-60 min.

10. Use of a nanofiber composite membrane according to any one of claims 1-5 in a nerve repair material.

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