Continuous fiber bionic meniscus and preparation method thereof

Abstract

The invention provides a continuous fiber bionic meniscus and a preparation method thereof, and relates to the technical field of medical materials. The continuous fiber bionic meniscus provided by the invention comprises a circumferential orientation layer and a radial orientation layer, the circumferential orientation layer is composed of continuous circumferential composite filaments; the radial orientation layer is composed of continuous radial composite filaments; the composite filament is formed by wrapping continuous fibers with a biocompatible polymer matrix. Continuous fibers are introduced into a polymer filament framework for reinforcement, collagen fibers are simulated through composite filaments, the biomechanical property of the meniscus implant can be improved, remarkable anisotropy is generated, meanwhile, the continuous fibers can maintain the mechanical strength in vivo for a long time, long-term maintenance of the functions of the implant is facilitated, and the service life of the implant is prolonged. Therefore, the functional requirements of the bionic meniscus implant are met. The bionic meniscus implant is prepared by using a continuous fiber 3D printing process, the production efficiency is high, the required equipment is less, and the method is suitable for personalized customization.

Description

Technical Field

[0001] The invention relates to the technical field of biomedical materials, and in particular to a continuous fiber bionic meniscus and a preparation method thereof. Background Art

[0002] The meniscus is a pair of wedge-shaped fibrocartilage tissues located between the femoral condyle and the tibial plateau in the knee joint, which plays the role of bearing, transmitting loads, absorbing shock, lubricating and stabilizing the joint. The natural meniscus contains more than 72% water, 20% circumferential and radial collagen fibers, and 5% glycosaminoglycan (GAGs) network that fixes collagen fibers, showing a fiber-reinforced composite tissue. Meniscus injury is a common orthopedic disease caused by trauma and degenerative lesions. In the United States, meniscus injury accounts for 10-20% of all orthopedic surgeries, with about 1 million surgeries performed each year, which brings serious physical and psychological burdens to patients. Due to the insufficient blood supply and poor self-healing ability of the meniscus, total or partial meniscectomy is usually used clinically to treat meniscus injuries, but more and more evidence shows that this will aggravate knee instability and cartilage degeneration, and even lead to osteoarthritis.

[0003] Over the past few decades, although a variety of meniscal implants have been developed, including commercial alternatives that have been approved for clinical implantation: (Stryker Corporation, USA) and (Orteq Sports Medicine Ltd., UK) and achieved satisfactory patient-reported results, but most of them are homogeneous in structure and cannot match the anisotropic structure and mechanical properties of natural tissues, and the long-term treatment and recovery effects are limited. Therefore, it is still a huge challenge to develop meniscus implants with similar composition and structure to natural meniscus.

[0004] 3D bioprinting can accurately construct complex tissues. By stacking layers to build the desired 3D structure, it can be used to prepare various tissue engineering scaffolds to achieve ideal mechanical, physical, chemical and biological properties. The meniscus has a crescent shape and a wedge-shaped cross-section. The application of 3D printing technology can more quickly and conveniently prepare meniscus-shaped scaffolds. Natural polymers and synthetic polymers have been widely used in 3D printing bio-inks for meniscus tissue engineering. Synthetic polymers such as polycaprolactone (PCL) and thermoplastic polyurethane (TPU) are widely used to construct 3D printed scaffolds to mimic the microstructure of natural meniscus collagen fibers because of their wide sources, good processing performance, and mechanical properties close to those of meniscus tissue. Some 3D printed polymer implants with meniscus shapes have been developed, such as Bahcecioglu et al. filling 3D printed PCL scaffolds with agarose and gelatin methacrylate hydrogels, and their tensile moduli reached 27.4±3.8MPa and 28.1±6.9MPa, respectively (Bahcecioglu G, Hasirci N, Bilgen B, Hasirci V. Hydrogels of agarose, and methacrylated gelatin and hyaluronic acid are more supportive for in vitro meniscus regeneration than three dimensional printed polycaprolactone scaffolds. Int J Biol Macromol. 2019, 122, 1152.); Li et al. filled PCL scaffolds with silk fibroin sponges, and the tensile modulus of the composite scaffolds reached 13.402±3.119MPa (Li Z, Wu N, Cheng J, Sun M, Yang P, Zhao F, Zhang J, Duan X, Fu X, Zhang J, Hu

[0005] Although the reported modulus of a single PCL filament printed by 3D printing can reach 200 MPa, after being prepared into the shape of a bionic meniscus, the 3D printed polymer skeleton is a porous structure. Without the introduction of continuous fiber reinforcement, its overall anisotropy and circumferential tensile modulus are still far behind those of the natural meniscus (100-300 MPa). However, there are currently no reports on 3D printed continuous fiber bionic meniscus implants. Summary of the invention

[0006] The purpose of the present invention is to provide a continuous fiber bionic meniscus and a preparation method thereof. The meniscus provided by the present invention has significant anisotropy and matches the biomechanical properties of a natural meniscus.

[0007] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0008] The present invention provides a continuous fiber bionic meniscus, comprising a circumferential orientation layer and a radial orientation layer; the circumferential orientation layer is composed of continuous circumferential composite filaments; the radial orientation layer is composed of continuous radial composite filaments; the circumferential composite filaments and radial composite filaments are continuous fibers wrapped in a biocompatible polymer matrix.

[0009] Preferably, the volume fraction of the continuous fibers in the circumferential composite filaments and the radial composite filaments is 1 to 30%.

[0010] Preferably, the biocompatible polymer matrix comprises synthetic polymers and / or natural hydrogel materials.

[0011] Preferably, the continuous fibers include natural fibers and / or synthetic fibers.

[0012] Preferably, the natural fiber includes one or more of silk fiber, cellulose fiber and chitosan fiber;

[0013] The synthetic fiber includes one or more of nylon fiber, polylactic acid fiber, polyglycolic acid fiber, polylactic acid-glycolic acid fiber and polydioxanone fiber.

[0014] Preferably, the thickness of each circumferentially oriented layer and each radially oriented layer is independently 50 to 90% of the diameter of the corresponding composite filament.

[0015] Preferably, the pores formed by stacking the circumferential orientation layer and the radial orientation layer are filled with or not filled with a hydrogel containing biological factors.

[0016] The present invention provides a method for preparing the continuous fiber bionic meniscus described in the above scheme, comprising the following steps:

[0017] Generate a 3D digital model of the meniscus using computer-aided design software, and determine the structures of the circumferential orientation layer and the radial orientation layer in the 3D digital model in the CAD software;

[0018] The biocompatible polymer matrix and the continuous fibers are loaded into a continuous fiber 3D printer for preparing circumferential composite filaments and radial composite filaments, the 3D digital model is imported into software adapted for the 3D printer, and 3D printing is performed, the extruded composite filaments are stacked circumferentially and radially to form circumferential orientation layers and radial orientation layers, and the continuous fiber bionic meniscus is obtained.

[0019] Preferably, the 3D printing temperature is lower than the thermal deformation and thermal decomposition temperature of the continuous fibers, while being able to extrude the biocompatible matrix.

[0020] Preferably, when the pores formed by the accumulation of the circumferential orientation layer and the radial orientation layer are filled with a hydrogel containing biological factors, after completing the 3D printing, it also includes: injecting a hydrogel precursor solution containing biological factors into the structure obtained by 3D printing, curing, and forming a hydrogel containing biological factors in the pores.

[0021] The present invention provides a continuous fiber bionic meniscus, comprising a circumferential orientation layer and a radial orientation layer; the circumferential orientation layer is composed of continuous circumferential composite filaments; the radial orientation layer is composed of continuous radial composite filaments; the circumferential composite filaments and the radial composite filaments are continuous fibers wrapped in a biocompatible polymer matrix. The present invention introduces continuous fiber reinforcement into the polymer filament skeleton, and uses composite filament bionic collagen fibers to improve the biomechanical properties of the meniscus implant and produce significant anisotropy. At the same time, the continuous fiber can maintain mechanical strength for a long time in the body, which is conducive to the long-term maintenance of the implant function, thereby meeting the functional requirements of the bionic meniscus implant.

[0022] The present invention provides a method for preparing the continuous fiber bionic meniscus described in the above scheme, which is convenient and fast to prepare. The present invention uses a continuous fiber 3D printing process, which has high production efficiency, requires less equipment, and is suitable for personalized customization. Based on the present invention, it allows the implant to be cut into a suitable size and shape without affecting its function, and is used to replace part of the meniscus.

[0023] The present invention utilizes 3D printing to accurately control the circumferential and radial structures of the composite filaments, as well as the orientation and distribution of specific areas, thereby being closer to the structure of natural meniscus tissue. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A top view of the structure of the circumferential orientation layer and the radial orientation layer in one embodiment of the present invention (A) and a schematic diagram of the circumferential orientation direction and the radial orientation direction of the composite filament of the present invention (B);

[0025] Figure 2 Schematic diagram of a single circumferential orientation layer (A) and a single radial orientation layer (B) of the continuous fiber bionic meniscus of the present invention; and annular patterns (C) and (D) formed by mirroring the above patterns along the cutting line;

[0026] Figure 3 Schematic diagram of the radial cross section of the continuous fiber bionic meniscus of the present invention (A), an enlarged view of the cross section of the composite filament (B) and a scanning electron microscope photograph of the cross section of the bionic meniscus (C);

[0027] Figure 4 3D structural model schematic diagram of the continuous fiber bionic meniscus of Example 1 of the present invention (A) and the printed continuous fiber bionic meniscus 3D structural entity (B);

[0028] In the figure: 1-composite filament pattern layer structure, 11-red area, 12-white area; 2-circumferential orientation layer, 20-circumferential direction, 21-circumferential composite filaments, 211-red area circumferential composite filaments, 212-white area circumferential composite filaments, 22-connections between circumferential composite filaments; 3-radial orientation layer, 30-radial direction, 31-radial composite filaments, 32-connections between radial composite filaments; 4-continuous fibers; 5-biocompatible polymer matrix; 6-cutting lines. DETAILED DESCRIPTION

[0029] The present invention provides a continuous fiber bionic meniscus, comprising a circumferential orientation layer and a radial orientation layer; the circumferential orientation layer is composed of continuous circumferential composite filaments; the radial orientation layer is composed of continuous radial composite filaments; the circumferential composite filaments and radial composite filaments are continuous fibers wrapped in a biocompatible polymer matrix.

[0030] like Figure 1 As shown in A, the continuous fiber bionic meniscus 1 of the present invention comprises a circumferential orientation layer 2 and a radial orientation layer 3, and the circumferential orientation layer 2 and the radial orientation layer 3 are stacked alternately.

[0031] In the present invention, the circumferential orientation layer 2 is composed of continuous circumferential composite filaments 21, such as Figure 2 As shown in A; the radial orientation layer 3 is composed of continuous radial composite filaments 31, such as Figure 2 As shown in B. Figure 1 In B, the circumferential direction 20 and the radial direction 30 are shown.

[0032] In the present invention, the circumferential orientation layer 2 is divided into a red area 11 and a white area 12; preferably, the circumferential composite filaments 211 in the red area 11 are arranged closely, and the radial composite filaments 212 in the white area 12 are arranged loosely (see Figure 1 Middle A and Figure 2In A), more preferably, the distance between adjacent circumferential composite filaments 212 in the white zone is 1 to 2 times the distance between adjacent circumferential composite filaments 211 in the red zone. Further preferably, the circumferential filament spacing has a gradient distribution from narrow to wide from the outer edge of the red zone to the inner edge of the white zone, and the ratio of the narrowest and widest spacings is 1:2, so as to simulate the collagen orientation distribution and mechanical properties of the red and white zones of the natural meniscus.

[0033] In the present invention, the circumferential composite filaments in each circumferential orientation layer 2 are in a continuous state, and adjacent circumferential composite filaments 21 are connected end to end by connecting lines 22 to form a continuous line.

[0034] Similarly, the radial composite filaments in each radial orientation layer 3 of the present invention are also continuous, and adjacent radial composite filaments 31 are connected end to end by connecting lines 32 to form continuous lines. In the present invention, in each radial orientation layer 3, the angles between adjacent radial composite filaments are the same, preferably 10-20°.

[0035] In a specific embodiment of the present invention, the circumferential orientation layer 2 and the radial orientation layer 3 are mirror-copied into an annular pattern along the cutting line 6 and prepared by 3D printing. After the preparation, they are cut along the cutting line 6 to obtain a pair of continuous fiber bionic menisci (see Figure 2 Middle C and Figure 2 (middle D).

[0036] In the present invention, from the bottom to the top of the meniscus, the circumferential orientation layer 2 sequentially reduces a number of circumferential composite filaments 21 from the center to the outside; from the bottom to the top, the radial orientation layer 3 sequentially reduces the length of the radial composite filaments 31 from the center to the outside, thereby forming a wedge-shaped meniscus, such as Figure 3 As shown in A.

[0037] In the present invention, the composite filaments (including circumferential composite filaments and radial composite filaments) are continuous fibers wrapped in a biocompatible polymer matrix, such as Figure 3 As shown in B, 5 is a biocompatible polymer matrix and 4 is a continuous fiber.

[0038] In the present invention, the volume fraction of the continuous fibers in the circumferential composite filaments and radial composite filaments is preferably 1 to 30%, more preferably 5 to 25%, and further preferably 10 to 20%.

[0039] In the present invention, the biocompatible polymer matrix preferably includes synthetic polymers and / or natural hydrogel materials; the synthetic polymer preferably includes one or more of polycaprolactone (PCL), thermoplastic polyurethane (TPU), polylactic acid (PLA), polyglycolic acid (PGA), polysuccinate and polyadipate. The present invention has no special requirements for the natural hydrogel material, and any natural hydrogel material known in the art can be used. In the present invention, the molecular weight of the biocompatible polymer matrix is ​​preferably 20,000 to 1,000,000 Da.

[0040] In the present invention, the continuous fibers preferably include natural fibers and / or synthetic fibers; the natural fibers preferably include one or more of silk fibers, cellulose fibers and chitosan fibers; the synthetic fibers preferably include one or more of nylon (PA) fibers, polylactic acid (PLA) fibers, polyglycolic acid (PGA) fibers, polylactic acid-glycolic acid (PLGA) fibers and polydioxanone (PPDO) fibers.

[0041] The present invention introduces continuous fiber reinforcement into the polymer filament skeleton to form composite filament bionic collagen fibers, which can improve the biomechanical properties of the meniscus implant and produce significant anisotropy. At the same time, the continuous fibers can maintain mechanical strength for a long time in the body, which is beneficial to the long-term maintenance of the implant function, thereby meeting the functional requirements of the bionic meniscus implant.

[0042] In the present invention, the thickness of each circumferential orientation layer and each radial orientation layer is independently preferably 50-90% of the diameter of the corresponding composite filament, and further preferably 60-80%; the diameter of the circumferential composite filament and the radial composite filament is preferably 0.2-0.4 mm (referring to the diameter of the composite filament just extruded by 3D printing. The composite filament will become flat after being deposited on the substrate. Therefore, the thickness of the orientation layer is smaller than the diameter of the composite filament).

[0043] In the present invention, the pores formed by the stacking of the circumferential orientation layer and the radial orientation layer are preferably filled or filled with a hydrogel containing biological factors. The present invention can achieve more biological functions by filling the structural pores of the continuous fiber bionic meniscus with a hydrogel containing biological factors. The present invention does not make special requirements on the specific composition of the hydrogel containing biological factors, and a suitable composition can be selected according to actual needs. In an embodiment of the present invention, the hydrogel is specifically formed by a 4% methacrylated silk protein aqueous solution.

[0044] The present invention provides a method for preparing the continuous fiber bionic meniscus described in the above scheme, comprising the following steps:

[0045] Generate a 3D digital model of the meniscus using computer-aided design software, and determine the structures of the circumferential orientation layer and the radial orientation layer in the 3D digital model in the CAD software;

[0046] The biocompatible polymer matrix and the continuous fibers are loaded into a continuous fiber 3D printer for preparing circumferential composite filaments and radial composite filaments, the 3D digital model is imported into software adapted for the 3D printer, and 3D printing is performed, the extruded composite filaments are stacked circumferentially and radially to form circumferential orientation layers and radial orientation layers, and the continuous fiber bionic meniscus is obtained.

[0047] In the present invention, the 3D digital model of the meniscus can be obtained by magnetic resonance imaging (MRI), micro-CT imaging or other 3D scanning methods, and the present invention does not make any special limitation on this.

[0048] The present invention has no special requirements for the 3D printing conditions, and the printing conditions known in the art can be selected according to the types of the biocompatible polymer matrix and the continuous fiber. In the present invention, the 3D printing temperature is preferably lower than the thermal deformation and thermal decomposition temperature of the continuous fiber, while being able to extrude the biocompatible matrix.

[0049] The present invention can further cut the printed 3D structure entity into a desired size and shape for partial meniscus replacement.

[0050] In the present invention, when the pores formed by the stacking of the circumferential orientation layer and the radial orientation layer are filled with a hydrogel containing biological factors, the present invention preferably also includes injecting a hydrogel precursor solution containing biological factors into the structure obtained by 3D printing, curing it, and forming a hydrogel containing biological factors in the pores.

[0051] The mechanical properties and anisotropy of the continuous fiber bionic meniscus obtained by the preparation method provided by the present invention are close to those of the natural meniscus; in addition, combined with the 3D printing method, the arrangement direction of the continuous fibers can be more accurately controlled, which is consistent with the orientation and distribution characteristics of the collagen fibers in the natural meniscus, and the rapid manufacturing of customized implants can be achieved.

[0052] The continuous fiber bionic meniscus and the preparation method thereof provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0053] Example 1

[0054] 1) Scan the knee joint of an adult New Zealand rabbit with MRI to obtain a 3D model of the meniscus and its size. Figure 1The composite filament pattern layer structure design continuous fiber bionic meniscus 3D model shown in the figure has an outer edge radius of 6 mm, an inner edge radius of 1.2 mm, and a height of 2.64 mm. It is stacked in the order of "circumferential-radial-...-circumferential-circumferential-circumferential" from bottom to top, with a total of 11 layers;

[0055] 2) using a continuous fiber 3D printer to prepare, loading silk fibers with a linear density of 47 deniers and polycaprolactone with a molecular weight of 80,000 Da into the 3D printer, and importing the 3D digital model into software adapted for the 3D printer;

[0056] 3) The 3D printer prints the composite filament pattern according to the instruction, the printed filament diameter is about 0.35mm, the printing layer height is 0.24mm, the printing temperature is 120°C, and the filament layers are continuously printed during the printing process. After the preparation is completed, it is cut along the cutting line into a pair of continuous fiber bionic menisci 1a with a wedge-shaped structure. The printed model and the actual picture are shown in Figure 4 As shown, A is a schematic diagram of the 3D structure model, and B is a printed continuous fiber bionic meniscus 3D structure entity; Figure 3 Center C is a scanning electron microscope photograph of the bionic meniscus cross section.

[0057] A pure polycaprolactone bionic meniscus 1b with the same structure but without continuous fibers was printed according to the above method as a control.

[0058] Example 2

[0059] 1) Scan the knee joint of an adult New Zealand rabbit with MRI to obtain a 3D model of the meniscus and its size. Figure 1 The composite filament pattern layer structure design continuous fiber bionic meniscus 3D model shown in the figure has an outer edge radius of 6 mm, an inner edge radius of 1.2 mm, and a height of 2.64 mm. It is stacked in the order of "circumferential-radial-...-circumferential-circumferential-circumferential" from bottom to top, with a total of 11 layers;

[0060] 2) using a continuous fiber 3D printer to prepare, loading silk fibers with a linear density of 47 deniers and thermoplastic polyurethane with a molecular weight of 32,000 Da into the 3D printer, and importing the 3D digital model into software compatible with the 3D printer;

[0061] 3) The 3D printer prints the composite filament pattern according to the instruction, the printed filament diameter is about 0.3 mm, the printing layer height is 0.24 mm, the printing temperature is 140° C. During the printing process, the filament layers are continuously printed. After the preparation is completed, a pair of continuous fiber bionic menisci 2a with a wedge-shaped structure are cut along the cutting line.

[0062] A pure thermoplastic polyurethane bionic meniscus 2b with the same structure but without continuous fibers was printed according to the above method as a control.

[0063] Example 3

[0064] 1) Scan the knee joint of an adult beagle with MRI to obtain a 3D model of the meniscus and its size. Figure 1 The composite filament pattern layer structure design continuous fiber bionic meniscus 3D model shown in the figure has an outer edge radius of 7.5 mm, an inner edge radius of 1.5 mm, a height of 2.64 mm, and is stacked in the order of "circumferential-radial-...-circumferential-circumferential-circumferential" from bottom to top, with a total of 11 layers;

[0065] 2) using a continuous fiber 3D printer to prepare, loading PLGA fiber sutures with a line diameter of 0.12 mm and polycaprolactone with a molecular weight of 80,000 Da into the 3D printer, and importing the 3D digital model into software adapted for the 3D printer;

[0066] 3) The 3D printer prints the composite filament pattern according to the instruction, the printed filament diameter is about 0.3 mm, the printing layer height is 0.24 mm, the printing temperature is 120° C. During the printing process, the filament layers are continuously printed. After the preparation is completed, a pair of continuous fiber bionic menisci 3 with a wedge-shaped structure is cut along the cutting line.

[0067] Example 4

[0068] 1) Scan the knee joint of an adult New Zealand rabbit with MRI to obtain a 3D model of the meniscus and its size. Figure 1 The composite filament pattern layer structure design continuous fiber bionic meniscus 3D model shown in the figure has an outer edge radius of 7.5 mm, an inner edge radius of 1.5 mm, a height of 2.64 mm, and is stacked in the order of "circumferential-radial-...-circumferential-circumferential-circumferential" from bottom to top, with a total of 11 layers;

[0069] 2) Prepared using a continuous fiber 3D printer, loading a nylon fiber suture with a wire diameter of 0.10 mm and PCL with a molecular weight of 80,000 Da into the continuous fiber 3D printer, and importing the 3D digital model into software adapted for the 3D printer;

[0070] 3) The 3D printer prints the composite filament pattern according to the instruction, with a printed filament diameter of about 0.3 mm, a printed layer height of 0.24 mm, a printing temperature of 120° C. During the printing process, continuous printing is maintained between filament layers to prepare a solid body with a 3D structure.

[0071] 4) injecting a methacrylated silk protein aqueous solution with a mass fraction of about 4% into the printed entity, so that the aqueous solution fills the pores of the meniscus, and curing it under a 405nm ultraviolet lamp for 30s, cutting off the excess hydrogel with a scalpel, and cutting along the cutting line to form a pair of continuous fiber bionic menisci with a wedge-shaped structure 4.

[0072] Performance Testing

[0073] Mechanical properties test: The circumferential tensile and compressive properties of the continuous fiber bionic meniscus were tested using a ZwickiLine Z0.5 TH electronic universal materials testing machine.

[0074] Cytotoxicity test: In vitro cytotoxicity test was performed according to GB / T 16886.5-2017.

[0075] The test results are shown in Table 1:

[0076] Table 1 Mechanical properties and in vitro cytotoxicity of the meniscus obtained in Examples 1 to 4

[0077]

[0078] As can be seen from Table 1, the continuous fiber bionic meniscus provided by the present invention has a significantly improved circumferential tensile modulus compared to the bionic meniscus without continuous fibers, and its mechanical properties are similar to those of the natural meniscus. In addition, the present invention can determine the appropriate fiber volume fraction and printing line spacing according to the selected different materials to flexibly match the biomechanical properties of the natural meniscus.

[0079] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A continuous fiber bionic meniscus, characterized in that: It comprises a circumferential orientation layer and a radial orientation layer; the circumferential orientation layer is composed of continuous circumferential composite filaments; the radial orientation layer is composed of continuous radial composite filaments; the circumferential composite filaments and radial composite filaments are continuous fibers wrapped in a biocompatible polymer matrix.

2. The continuous fiber bionic meniscus according to claim 1, characterized in that: The volume fraction of the continuous fibers in the circumferential composite filaments and the radial composite filaments is 1 to 30%.

3. The continuous fiber bionic meniscus according to claim 1, characterized in that: The biocompatible polymer matrix includes synthetic polymers and / or natural hydrogel materials.

4. The continuous fiber bionic meniscus according to claim 1 or 2, characterized in that: The continuous fibers include natural fibers and / or synthetic fibers.

5. The continuous fiber bionic meniscus according to claim 4, characterized in that: The natural fibers include one or more of silk fibers, cellulose fibers and chitosan fibers; The synthetic fiber includes one or more of nylon fiber, polylactic acid fiber, polyglycolic acid fiber, polylactic acid-glycolic acid fiber and polydioxanone fiber.

6. The continuous fiber bionic meniscus according to claim 1, characterized in that: The thickness of each circumferentially oriented layer and each radially oriented layer is independently 50 to 90% of the diameter of the corresponding composite filament.

7. The continuous fiber bionic meniscus according to claim 1, characterized in that: The pores formed by the stacking of the circumferential orientation layer and the radial orientation layer are filled or not filled with hydrogel containing biological factors.

8. The method for preparing the continuous fiber bionic meniscus according to any one of claims 1 to 7, characterized in that: The following steps are involved: Generate a 3D digital model of the meniscus using computer-aided design software, and determine the structures of the circumferential orientation layer and the radial orientation layer in the 3D digital model in the CAD software; The biocompatible polymer matrix and the continuous fibers are loaded into a continuous fiber 3D printer for preparing circumferential composite filaments and radial composite filaments, the 3D digital model is imported into software adapted for the 3D printer, and 3D printing is performed, the extruded composite filaments are stacked circumferentially and radially to form circumferential orientation layers and radial orientation layers, and the continuous fiber bionic meniscus is obtained.

9. The preparation method according to claim 8, characterized in that: The 3D printing temperature is lower than the thermal deformation and thermal decomposition temperature of the continuous fibers, while being able to extrude the biocompatible matrix.

10. The preparation method according to claim 8, characterized in that: When the pores formed by the accumulation of the circumferential orientation layer and the radial orientation layer are filled with a hydrogel containing biological factors, after the 3D printing is completed, the method further includes: injecting a hydrogel precursor solution containing biological factors into the structure obtained by 3D printing, curing it, and forming a hydrogel containing biological factors in the pores.

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