Spiral reinforced composite structure artificial ligament with bunchy characteristic and preparation method of spiral reinforced composite structure artificial ligament

Abstract

The invention discloses a spiral reinforced composite structure artificial ligament with a bundle characteristic and a preparation method thereof, and belongs to the technical field of biomedical materials. The artificial ligament is of a composite structure, is composed of a plurality of units and has a bundle-shaped characteristic. When the artificial ligament is stretched in the axial direction, the negative Poisson's ratio effect is achieved in the direction perpendicular to the axial direction. The structure of each unit is a spiral reinforced knitted structure and is prepared and formed by adopting a textile technology. The artificial ligament is formed by weaving a medical-grade fiber material or a surface-modified fiber material with biocompatibility. The physical characteristics such as the size, the surface roughness, the surface mesh size, the tensile mechanical behavior and the rigidity of the artificial ligament can be regulated and controlled through the design of a textile weave structure and process parameters. The physical performance of the artificial ligament can be regulated and controlled by changing the preparation process, tissue growth is better promoted so as to be better combined with a marrow tract interface, and the nonlinear stretching mechanical behavior of a natural ligament under the stress working condition is simulated.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of biomedical materials, and relates to a spiral reinforced composite structure artificial ligament with bundle characteristics and a preparation method thereof. BACKGROUND

[0002] As a key implant device in the field of sports medicine, artificial ligaments are widely used in knee joint cross ligament reconstruction, shoulder joint stabilization surgery and the like. Traditional artificial ligaments are mostly designed in a homogeneous monofilament or dense braided structure (such as CN120037448A), but when subjected to periodic tensile load, the stress cannot be dispersed in multiple directions along the fiber bundle due to the lack of a multi-level bundle structure similar to the natural ligament, resulting in local stress concentration. The clinical manifestations are micro-motion damage of the graft-bone interface, bone tunnel expansion and long-term fixation failure. When stretched, the natural ligament realizes nonlinear stiffness change through the slippage and rearrangement of collagen fiber bundles. The traditional artificial ligament has a rigid structure, which produces a "piston effect" at the moment of joint flexion and extension, accelerating the wear of the bone tunnel. In addition, its dense structure hinders cell infiltration and collagen ingrowth, and due to the dense structure, the overall elasticity is small, and structural relaxation occurs after cyclic stretching (such as patent CN104043151A). SUMMARY

[0003] The purpose of the present application is to solve the problems in the background art and provide a spiral reinforced composite structure artificial ligament with bundle characteristics and a preparation method thereof.

[0004] To achieve the above-mentioned purpose, the technical solutions adopted by the present application are as follows: A preparation method of a spiral reinforced composite structure artificial ligament with bundle characteristics, the method comprising: Step 1: using a braiding machine to braid a biocompatible fiber material into an axially continuous braided wire with a small diameter (less than 1.20 mm); Step 2: feeding the braided wire and medical-grade fibers into a full-forming computerized flat knitting machine for shaped knitting to obtain a spiral reinforced knitted structure (diameter less than 4.00 mm); wherein the braided wire is looped in front and back needle beds according to a set process for knitting a spiral high-strength structure, and the medical-grade fibers are continuously looped in front and back needle beds for knitting a cylindrical elastic structure; the spiral high-strength structure and the cylindrical elastic structure together form a spiral reinforced knitted structure; the full-forming computerized flat knitting machine is a MACH2X model made by the Island Precision Machine Manufacturing Company; Step 3: assembling multiple spiral reinforced knitted structures according to specific requirements to obtain a spiral reinforced composite structure artificial ligament. The bundle characteristics of the spiral reinforced composite structure artificial ligament can be understood as that multiple slender spiral reinforced knitted structures form a bundle of spiral reinforced composite structure artificial ligaments.

[0005] In step two, the preparation of the spiral reinforced knitted structure requires the design of the structure, the selection of the fiber material, and the adjustment of the process parameters according to the specific fiber material. The most intuitive parameter representation of the change of the preparation process parameters is the weft density and the warp density. Therefore, the performance of the textile material (such as tensile mechanical behavior, breaking strength, surface roughness, mesh size, etc.) can be adjusted by changing or randomly combining any of the structure design, fiber material selection, and process parameter adjustment.

[0006] The artificial ligament is a composite structure composed of multiple units and has a bundle-like feature. When the artificial ligament is stretched along the axial direction, it has a negative Poisson's ratio effect in the direction perpendicular to the axial direction. The degree of deformation of the negative Poisson's ratio effect can be regulated by changing the structure, the preparation process parameters, or the combination of the unit structure. The structure of the unit is a spiral reinforced knitted structure, which is formed by using textile technology. The size, surface roughness, surface mesh size, tensile mechanical behavior, and stiffness of the artificial ligament can be regulated by designing the structure to optimize its biomechanical properties, promote tissue ingrowth and bone integration, and effectively simulate the stress behavior of natural ligaments. The artificial ligament can be designed to have different cross-sections according to specific needs.

[0007] The main body of the present application is a composite textile structure composed of spiral reinforced knitted structures assembled by spiral high-strength structures with high strength and low elasticity and cylindrical elastic structures with low strength and high elasticity. The multiple spiral reinforced knitted structures that make up the artificial ligament can have different structures, and the specific parameters can be adjusted according to actual needs. The spiral reinforced composite structure artificial ligament with a bundle-like feature has a tensile mechanical behavior (before breaking) similar to that of natural ligaments. The tensile mechanical behavior can be regulated by changing the structure and the process parameters, and is related to the selection of materials and the design of parameters. Because different materials have different strengths and elongations, the preparation process parameters need to be adjusted according to the characteristics of different materials.

[0008] Further, in step one, the fiber material is one or more of medical-grade fiber, polyester fiber, polypropylene fiber, or ultra-high molecular weight polyethylene fiber.

[0009] Further, in step one, the fiber material is subjected to surface modification treatment. Surface modification is to specifically improve the roughness of the fiber surface or load some functional nanomaterials on the fiber surface. For example, improving the roughness can promote cell adhesion, and loading some anti-inflammatory materials can effectively inhibit inflammation and promote tissue regeneration, providing a good microenvironment for repair.

[0010] Methods for improving the surface roughness of fibers include the following: (1) plasma treatment: power of about 80 W, time of 0.5-3 min, and gas of oxygen or air; (2) chemical grafting: introduction of polar groups such as hydroxyl, carboxyl, and amino groups; (3) surface coating: use of polydopamine, phosphorylcholine group-containing polymer, and silk fibroin to coat the fiber surface; and (4) functional nanomaterial loading: carbon nanotubes, hydroxyapatite, and nanometer-sized cerium dioxide.

[0011] The loading method of functional nanomaterials is not uniform and needs to be determined according to the specific nanomaterial. There are many methods that can be used, such as nanometer-sized cerium dioxide particles that can be fixed on the fiber surface through chelation by polydopamine coating; or the fiber surface can be etched by an alkaline solution to form a nanometer-sized rough structure, and active groups are introduced to fix the nanometer-sized cerium dioxide on the fiber surface. Taking the methods in the above answers as examples, the functional nanomaterial loading of (4) is actually achieved by the methods of (1)-(3), except that (1)-(3) can already change the roughness of the fiber surface, and only further load functional nanomaterials. Improving the roughness of the fiber surface can improve the adhesion efficiency of cells and regenerated tissues, but functional nanoparticles can have functions such as anti-inflammatory, promoting cell regeneration, and inducing cell directional differentiation.

[0012] Further, in step one, the knitting pitch is 0.01-4.0 mm, and the knitting speed is 10-80 r / min.

[0013] Further, in step two, the preparation process of the cylindrical elastic structure involves fabric technology, horizontal density, and vertical density, wherein the fabric technology is a specific process organization, there is no specific range, the horizontal density ranges from 8 to 14 needles / cm, and the vertical density ranges from 8 to 16 rows / cm.

[0014] Further, in step two, the spiral reinforcing knitted structure is integrally knitted and shaped, and the spiral high-strength structure is inserted in the form of a spiral inside the cylindrical elastic structure without the need for additional wrapping or other technologies.

[0015] Further, in step three, an outer binding layer is added outside all the spiral reinforcing knitted structures; the outer binding layer has the same or different structure as the spiral reinforcing knitted structure; the outer binding layer completely covers the unit structure in the axial direction, or only covers the upper, lower, or middle section of the unit structure in the axial direction, or covers any number of segmented areas; and the outer binding layer has a cross-sectional dimension that can be greater than, equal to, or less than the size of the bundle-shaped structure composed of units.

[0016] Further, in step three, the cross section of the artificial ligament perpendicular to the axial direction is adjusted by regulating the spatial arrangement and combination of the helical reinforced knitted structure, including but not limited to adjusting to a circular shape, an elliptical shape, a rectangular shape, etc.

[0017] Further, in step three, the artificial ligament is composed of helical reinforced knitted structures with or / and without negative Poisson's ratio effect according to specific needs. Assuming that the artificial ligament is composed of 6 unit structures: ① if all the 6 unit structures have negative Poisson's ratio effect, the overall deformation effect is the most obvious; ② if only 2 unit structures have negative Poisson's ratio effect and the remaining 4 unit structures do not have negative Poisson's ratio effect, the overall deformation effect will be significantly reduced. It can be adjusted according to specific needs.

[0018] The helical reinforced composite structure artificial ligament with bundle characteristics, the helical reinforced knitted structure, the helical high-strength structure and the tubular elastic structure of the application can adjust the size, surface roughness, surface mesh size and rigidity and other physical properties through the design of the textile structure. The helical reinforced knitted structure, the tubular elastic structure, the structure of step two and the weft density and the warp density in claim 4 are related; the helical high-strength structure is related to the knitting process parameters in step one; the helical reinforced composite structure artificial ligament with bundle characteristics is related to the structure of step two and the weft density / warp density in claim 4, the knitting process parameters in step one and the assembly method in step three.

[0019] A helical reinforced composite structure artificial ligament with bundle characteristics prepared by the above method.

[0020] The beneficial effects of the present application relative to the prior art are: compared with the traditional artificial ligament, the artificial ligament with bundle characteristics of the present application can simulate the nonlinear stiffness response of the natural ligament through the sliding mechanism between the bundles and the deformation mechanism of the unit structure. At the same time, the bundle structure will produce radial expansion due to the negative Poisson's ratio effect of the unit structure when stretched in the axial direction, which can effectively inhibit the "piston effect" caused by the radial contraction of the traditional ligament to reduce the bone tunnel expansion rate. Since the basic unit of the knitted structure is a loop, these loops form a continuous three-dimensional network through interlocking and interweaving, and the knitted structure has high porosity. This structure gives the artificial ligament good elasticity, while improving the surface roughness of the artificial ligament, allowing tissue to grow inward and implant integration. In addition, compared with the traditional tight structure, the stiffness of the bundle structure is greatly reduced, and the cylindrical structure in the unit will collapse and deform when deformed under stress, which can effectively avoid rigid extrusion or rigid friction with other contactable parts. The artificial ligament can realize the controllable adjustment of key physical properties (such as size, surface roughness, mesh size, tensile mechanical behavior, stiffness, and especially Poisson's ratio effect) through structural design, so as to optimize its biomechanical properties, promote tissue ingrowth and bone integration ability, and effectively simulate the stress behavior of natural ligament, which has important clinical significance and application value. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a schematic view of the artificial ligament with bundle characteristics of the present application; Figure 2 is a schematic view of the unit structure of the artificial ligament with bundle characteristics of the present application; Figure 3 is a negative Poisson's ratio deformation effect diagram of the unit structure of the artificial ligament with bundle characteristics of the present application; Figure 4 is a negative Poisson's ratio deformation effect diagram of the artificial ligament with bundle characteristics of the present application; Figure 5 is a cross-sectional effect schematic diagram of Example 1; Figure 6 is a schematic diagram of the unit structure knitting process of Examples 1 and 2; Figure 7 is a process diagram of Example 1 and 2; Figure 8 is a cross-sectional effect schematic diagram of Example 2; Figure 9 is a unit structure diagram of Example 2; Figure 10 is a schematic view of the artificial ligament with bundle characteristics of the present application of Example 2; Figure 11A weave chart for the outer layer of the bundle of Example 2; Figure 12 A stress-strain curve of the spiral reinforced composite structure artificial ligament with bundle-like features in Example 2. DETAILED DESCRIPTION

[0022] In order to make the objects, technical solutions and advantages of the present application clearer, the following further describes the present application with reference to the accompanying drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application, but not to limit the present application.

[0023] Example 1 The spiral reinforced composite structure artificial ligament with bundle-like features described in the embodiment of the present application is shown in Figure 1 .

[0024] The spiral reinforced composite structure artificial ligament with bundle-like features described in the embodiment of the present application is composed of 8 units, and its cross section is oval-shaped, as shown in Figure 5 .

[0025] The unit constituting the spiral reinforced composite structure artificial ligament with bundle-like features described in the embodiment of the present application is shown in Figure 2 , and its negative Poisson's ratio effect in the deformation process is shown in Figure 3 . The specific weaving method is as follows: A high-strength braided wire with a diameter of 0.65 mm is woven on an 8-spindle braiding machine using 200D ultra-high molecular weight polyethylene fibers, and then fed into an E18 full-forming computerized flat knitting machine together with 300D polyester fibers for co-weaving. The braided wire woven from ultra-high molecular weight polyethylene fibers is interlaced according to the weave chart on the front and rear needle beds in turn, and is used to weave the spiral high-strength structure; the medical-grade polyester fibers are looped according to the weave chart on the front and rear needle beds in turn, and are used to weave the cylindrical elastic structure. The spiral high-strength structure is regularly inserted in a spiral shape inside the cylindrical elastic structure, and the pitch is 10.00 mm.

[0026] The weaving process is shown in Figure 6 , and the weave chart is shown in Figure 7 .

[0027] Then the unit structures are combined together to obtain the spiral reinforced composite structure artificial ligament with bundle-like features, as shown in Figure 1 . And its negative Poisson's ratio effect is shown in Figure 4 .

[0028] The fiber material used in the spiral-reinforced composite artificial ligament with bundle-like characteristics described in this invention embodiment can be any synthetic fiber, natural fiber, or surface-modified biocompatible fiber that meets medical and ligament functional requirements, such as silk fiber, polypropylene fiber, polylactic acid fiber, etc.

[0029] Example 2 The spiral-reinforced composite artificial ligament with bundle-like characteristics described in the embodiments of the present invention is as follows: Figure 8 As shown.

[0030] The spiral-reinforced composite artificial ligament with bundle-like characteristics described in this embodiment of the invention consists of 6 units, with a square-round cross-section, as shown below. Figure 8 As shown.

[0031] The units constituting the helical reinforced composite artificial ligament with bundle-like characteristics described in the embodiments of the present invention are as follows: Figure 9 As shown, and its negative Poisson's ratio effect during deformation is as follows: Figure 3 As shown. The specific weaving method is as follows: High-strength braided yarn with a diameter of 0.65 mm is woven from 200D ultra-high molecular weight polyethylene fiber on an 8-spindle knitting machine. This yarn is then fed together with 0.20 mm diameter polypropylene monofilament into an E18 fully-fledged computerized flat knitting machine for joint weaving. The ultra-high molecular weight polyethylene fiber yarn is alternately layered on the front and rear needle beds according to the weave process to create a high-strength spiral structure. Medical-grade polypropylene monofilament fibers are also alternately looped on the front and rear needle beds according to the weave process to create a tubular elastic structure. The high-strength spiral structure is intermittently interwoven within the tubular elastic structure with a pitch of 6.00 mm.

[0032] Then, the unit structures are assembled together, and a binding layer is added to the outer layer of the units to obtain a helical reinforced composite artificial ligament with bundle-like characteristics, such as... Figure 10 As shown.

[0033] The binding layer is a tubular material with a weft-flat weave structure, which can be knitted by a fully-formed computerized flat knitting machine. Its fabrication process diagram is shown below. Figure 11 As shown.

[0034] The helical reinforced composite artificial ligament with bundle-like characteristics described in this invention exhibits tensile mechanical behavior highly similar to that of natural ligaments, and possesses a J-shaped characteristic, such as... Figure 12 As shown.

Claims

1. A method of making a helical reinforced composite structure artificial ligament having a fascicle feature, characterized by: The method is: Step one: using a braiding machine to braid biocompatible fiber material into an axially continuous braided line with a small diameter (less than 1.20 mm); Step two: feeding the braided line and medical-grade fiber into a full-forming computerized flat knitting machine for shaped knitting to obtain a spiral reinforced knitted structure (diameter less than 4.00 mm); wherein the braided line is looped in the front and back needle beds according to the set process for knitting a spiral high-strength structure, and the medical-grade fiber is continuously looped in the front and back needle beds for knitting a cylindrical elastic structure; the spiral high-strength structure and the cylindrical elastic structure together form a spiral reinforced knitted structure; Step three: assembling multiple spiral reinforced knitted structures according to specific needs to obtain a spiral reinforced composite structure artificial ligament.

2. The method of claim 1, wherein the method further comprises: providing a plurality of bundles of fibers; and providing a plurality of reinforcing fibers; and combining the plurality of bundles of fibers and the plurality of reinforcing fibers to form the composite structure. In step one, the fiber material is one or more of medical-grade fiber, polyester fiber, polypropylene fiber, or ultra-high molecular weight polyethylene fiber.

3. The method of claim 1 or 2, wherein the method further comprises: In step one, the fiber material is surface modified.

4. The method of claim 1, wherein the method further comprises: providing a plurality of bundles of fibers; and providing a plurality of reinforcing fibers; and combining the plurality of bundles of fibers and the plurality of reinforcing fibers to form the composite structure. In step one, the braiding pitch is 0.01-4.0 mm, and the braiding speed is 10-80 r / min.

5. The method of claim 1, wherein the method further comprises: providing a plurality of bundles of fibers; and providing a plurality of reinforcing fibers; and combining the plurality of bundles of fibers and the plurality of reinforcing fibers to form the composite structure. In step two, the parameters involved in the preparation process of the cylindrical elastic structure include fabric process, horizontal density, and vertical density, with a horizontal density range of 8-14 needles / cm and a vertical density range of 8-16 rows / cm.

6. The method of claim 1, wherein the method further comprises: providing a plurality of bundles of fibers; and providing a plurality of reinforcing fibers; and combining the plurality of bundles of fibers and the plurality of reinforcing fibers to form the composite structure. In step two, the spiral reinforced knitted structure is integrally knitted and formed, and the spiral high-strength structure is inserted in the form of a spiral inside the cylindrical elastic structure.

7. The method of claim 1, wherein the method further comprises: providing a plurality of bundles of fibers; and providing a plurality of reinforcing fibers; and combining the plurality of bundles of fibers and the plurality of reinforcing fibers to form the composite structure. In step three, an outer binding layer is added to the outside of all spiral reinforced knitted structures; the outer binding layer can have the same or different structure as the spiral reinforced knitted structure; the outer binding layer completely covers the unit structure in the axial direction, or only covers the upper, lower, or middle section of the unit structure in the axial direction, or covers different numbers of sectional areas; the outer binding layer can have a cross-sectional dimension that is larger than, equal to, or smaller than the size of the bundled structure composed of units.

8. The method of claim 1, wherein the method further comprises: providing a plurality of bundles of fibers; and providing a plurality of reinforcing fibers; and combining the plurality of bundles of fibers and the plurality of reinforcing fibers to form the composite structure. In step three, the cross-section of the artificial ligament perpendicular to the axial direction is adjusted by regulating the spatial arrangement and combination of the spiral reinforced knitted structure.

9. The method of claim 1, wherein the method further comprises: providing a plurality of bundles of fibers; and providing a plurality of reinforcing fibers; and combining the plurality of bundles of fibers and the plurality of reinforcing fibers to form the composite structure. In step three, the artificial ligament is composed of spiral reinforced knitted structures with or without negative Poisson's ratio effect according to specific needs.

10. A spiral reinforced composite structure artificial ligament with a bundled feature prepared by the method of any one of claims 1-9.

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