Composite stent for rotator cuff repair and preparation method thereof

Abstract

The invention discloses a composite stent for rotator cuff repair and a preparation method thereof, and belongs to the field of medical instruments. The stent comprises a sheet-shaped composite layer and a strip-shaped composite layer, the sheet-shaped layer is formed by compounding a synthetic polymer woven body with a natural polymer sponge, the strip-shaped layer is formed by compounding a synthetic polymer woven body with a natural sponge containing nano-hydroxyapatite, the sheet-shaped layer and the strip-shaped layer are directly connected through a warp knitting or weft knitting process, and the width ratio is (5: 1)-(10: 1). During preparation, the woven sheet layer and the woven strip layer are soaked in a natural polymer solution and a solution containing nano-hydroxyapatite respectively, and the porous sponge composite is formed through pre-freezing and freeze-drying. According to the scaffold, mechanical strength matching is achieved through weaving connection, bone regeneration is induced in a targeted mode through hydroxyapatite, meanwhile, the porous sponge is matched with soft tissue healing, the problems that a traditional patch is poor in bone tunnel integration and interface stress is concentrated are solved, and the scaffold is suitable for rotator cuff injury repair.

Description

Technical Field

[0001] The present invention relates to the field of medical devices, in particular to a composite stent for rotator cuff repair and a preparation method thereof. Background Art

[0002] Rotator cuff injury is a common disease of the shoulder joint, especially the huge rotator cuff tear which is the most difficult to repair. Traditional suture anchor technology cannot solve the defect tissue contracture and bone canal healing obstacles, and the existing patch technology (such as CN202210062216.5 three-section bone-ligament-bone scaffold, CN202010144383.5 gradient tendon-bone scaffold) provides mechanical support, but still has significant defects:

[0003] 1. Structural limitations: Most existing stents are segmented composites (such as bone-ligament-bone), and their segmented connection interfaces are prone to breakage;

[0004] 2. Bone tunnel fusion disorder: The hydroxyapatite load is concentrated on the two end bone segments (such as CN202010330989.8), lacking the ability to integrate with the soft tissue gradient, leading to the risk of bone tunnel expansion;

[0005] 3. The preparation process is complex: the mineralization gradient solution needs to be impregnated in layers multiple times (CN202010144383.5), which is prone to sudden changes in interface porosity and inhibits bone cell ingrowth.

[0006] Therefore, there is an urgent need to develop an integrated scaffold with strong interface fusion, mechanical adaptability and bone induction function to solve the core problem of the difficulty of patch hosting. Summary of the invention

[0007] In view of the above situation, it is necessary to provide a composite stent for rotator cuff repair that solves at least one of the above problems, including:

[0008] The sheet-like composite layer is formed by a composite of a synthetic polymer braided body and a natural polymer sponge, wherein the synthetic polymer braided body is formed by a warp knitting or weft knitting process;

[0009] The long strip composite layer is composited by a synthetic polymer braid and a natural polymer sponge containing nano-hydroxyapatite, and the long strip composite layer is connected to the edge of the sheet composite layer by warp knitting or weft knitting;

[0010] The width of the long composite layer is 0.08-3 mm, and the width ratio of the sheet composite layer to the long composite layer in the connection area is (5:1)-(10:1).

[0011] Preferably, the synthetic polymer braid material is selected from at least one of polyethylene terephthalate, polypropylene, polyethylene, polydioxanone, polydioxanone, polycaprolactone, poly-L-lactide, and polyglycolic acid.

[0012] Preferably, the raw material of the natural polymer sponge is animal-derived collagen, recombinant collagen, gelatin, chitosan or silk fibroin.

[0013] Preferably, the mass proportion of nano-hydroxyapatite in the long composite layer is 0.5%-50% of the natural polymer material.

[0014] Preferably, the thickness of the sheet-like composite layer is 0.08-3 mm, and the thickness of the long strip composite layer is 0.08-3 mm.

[0015] Preferably, the long composite layer and the sheet-like composite layer are woven and connected by using the same synthetic polymer material, and the difference in yarn diameter between the two is ≤0.2 mm.

[0016] Preferably, the spacing between adjacent long composite layers is 0.1-3 cm.

[0017] Preferably, in the natural polymer solution containing nano-hydroxyapatite, the nano-hydroxyapatite is loaded on the natural polymer network by physical adsorption or chemical bonding.

[0018] The present invention also relates to a method for preparing a composite stent for rotator cuff repair, comprising the following steps:

[0019] 1) Weaving the synthetic polymer woven bodies of the sheet-like composite layer and the long composite layer respectively, and connecting the long composite layer to the edge of the sheet-like composite layer by warp knitting or weft knitting;

[0020] 2) immersing the sheet-shaped composite layer in a natural polymer solution, and immersing the long strip composite layer in a natural polymer solution containing nano-hydroxyapatite;

[0021] 3) The impregnated composite layer is pre-frozen and freeze-dried, the pre-freezing temperature is -20°C to -50°C, and the freeze-drying time is 24-72h.

[0022] Preferably, the immersion process conditions in step 2) are: solution concentration is 0.01-1 mg / mL, immersion temperature is 4-40°C, immersion time is 0.1-60 min, and the distance between the upper and lower interfaces of the braid and the solution surface during immersion is 0.1-3 mm. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic structural diagram of a composite stent for rotator cuff repair according to an embodiment of the present invention. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the bone-soft tissue integrated scaffold of the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0025] In the description of the present invention, unless otherwise specified, "multiple" means two or more; the terms "center", "longitudinal", "lateral", "up", "down", "left", "right", "inside", "outside", "front end", "rear end", "head", "tail", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate the orientation or position relationship based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third" and the like are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0026] In the description of this utility, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this utility can be understood by specific circumstances.

[0027] See also Figure 1 The composite stent for rotator cuff repair of an embodiment of the present invention comprises: a. a sheet-like composite layer (11), which is composed of a synthetic polymer braid and a natural polymer sponge, and the synthetic polymer braid is formed by a warp knitting or weft knitting process; b. a strip composite layer (12), which is composed of a synthetic polymer braid and a natural polymer sponge containing nano-hydroxyapatite, and the strip composite layer (12) is connected to the edge of the sheet-like composite layer (11) by a warp knitting or weft knitting process; c. the width of the strip composite layer (12) is 0.08-3mm, and the width ratio of the sheet-like composite layer (11) to the strip composite layer (12) in the connection area is (5:1)-(10:1).

[0028] The sheet-like composite layer (11) is composed of a polyethylene terephthalate (PET) warp-knitted diamond grid braided body and a natural polymer sponge impregnated with a collagen solution, and the long strip composite layer (12) is composed of a PET weft-knitted belt and a collagen sponge containing nano-hydroxyapatite, and is crocheted to the edge of the sheet-like composite layer (11) through warp-knitted stitches, and the width ratio of the two is 7:1; the porous woven structure of the sheet-like composite layer (11) is adapted to the elasticity of soft tissue, and the mineral gradient of the long strip composite layer (12) promotes the adhesion of bone cells in the bone canal, and the integration of the woven connection of the two ensures mechanical stability after implantation.

[0029] The synthetic polymer braided body material is selected from at least one of polyethylene terephthalate, polypropylene, polyethylene, polydioxanone, polydioxanone, polycaprolactone, poly-L-lactide, and polyglycolic acid. The sheet-like composite layer (11) is formed by warp-knitting hexagonal meshes with polypropylene (PP) yarns, and the long strip composite layer (12) is weft-knitted with polyglycolic acid (PGA) yarns and then grafted to the edge of the sheet-like composite layer (11); the high fatigue resistance of polypropylene prolongs the service life of the stent in the dynamic shoulder joint, and the degradability of polyglycolic acid is adapted to the autologous process in the late stage of bone healing.

[0030] The raw materials of the natural polymer sponge are animal-derived collagen, recombinant collagen, gelatin, chitosan or silk fibroin.

[0031] The natural polymer sponge of the sheet-like composite layer (11) is formed by impregnation with a 0.3 mg / mL chitosan solution, and the natural polymer sponge of the long composite layer (12) is formed by impregnation with a silk fibroin solution containing nano-hydroxyapatite; the antibacterial property of chitosan inhibits postoperative infection, and the toughness of silk fibroin synergistically improves the efficiency of bone canal edge regeneration with hydroxyapatite.

[0032] See also Figure 1 In another embodiment, the mass proportion of nano-hydroxyapatite in the long composite layer (12) is 0.5%-50% of the natural polymer material.

[0033] The mass proportion of nano-hydroxyapatite in the long composite layer (12) is 25%, which is formed by impregnating a collagen solution containing hydroxyapatite. The loading amount is achieved by regulating the concentration gradient of the mineral solution, thereby ensuring the bone induction activity and preventing the sponge pores from being excessively blocked.

[0034] See also Figure 1 In another embodiment, the thickness of the sheet-like composite layer (11) is 0.08-3 mm, and the thickness of the long strip composite layer (12) is 0.08-3 mm.

[0035] The sheet-like composite layer (11) has a thickness of 1.2 mm and is knitted with high-density PET yarn to enhance tensile strength; the long strip composite layer (12) has a thickness of 0.3 mm and is knitted with low-density PET yarn to adapt to bone tunnel implantation. The differentiated thickness design balances the load distribution of the stent.

[0036] See also Figure 1 In another embodiment, the long composite layer (12) and the sheet composite layer (11) are woven and connected by the same synthetic polymer material, and the difference in yarn diameter between the two is ≤0.2 mm.

[0037] The sheet-like composite layer (11) and the long composite layer (12) are both woven with PET yarns having a diameter of 0.3 mm. The long layer (12) and the sheet-like layer (11) are directly connected through warp knitting loops. The polymer yarns of the same material and similar diameter ensure uniform strength of the connection interface, thereby avoiding structural delamination after suturing.

[0038] See also Figure 1 In another embodiment, the spacing between adjacent long composite layers (12) is 0.1-3 cm.

[0039] Three long composite layers (12) are arranged at an interval of 1 cm on the edge of the sheet-like composite layer (11), and the width of each long layer (12) is 1 mm. The spacing enables multi-point anchoring to disperse the tension during rotator cuff suturing, reduce the damage to the bone canal caused by single-point shear stress, and promote the continuous growth of the bone integration zone.

[0040] See also Figure 1 In another embodiment, in the natural polymer solution containing nano-hydroxyapatite, the nano-hydroxyapatite is loaded on the natural polymer network by physical adsorption or chemical bonding.

[0041] The nano-hydroxyapatite in the long composite layer (12) is chemically bonded to the gelatin network through a silane coupling agent, the coupling agent concentration of the solution is 1wt%, and the attachment rate of the mineral after immersion is increased to more than 95%, and the chemical bonding enhances the sustained release stability of the mineral after implantation.

[0042] The embodiment of the present invention also relates to a method for preparing a composite stent for rotator cuff repair, comprising the following steps: 1) separately weaving a synthetic polymer woven body of a sheet composite layer (11) and a long composite layer (12), and connecting the long composite layer (12) to the edge of the sheet composite layer (11) by warp knitting or weft knitting; 2) immersing the sheet composite layer (11) in a natural polymer solution, and immersing the long composite layer (12) in a natural polymer solution containing nano-hydroxyapatite; 3) pre-freezing and freeze-drying the impregnated composite layer, the pre-freezing temperature is -20°C to -50°C, and the freeze-drying time is 24-72h.

[0043] In step 1, the sheet-like composite layer (11) is warp-knitted with PET yarn to form a diamond grid, and the long composite layer (12) is weft-knitted with the same material PET yarn into a band with a width of 0.8 mm, and is crocheted to the edge of the sheet-like layer (11) through warp knitting stitches, and the connection interval between the two is 1 cm; in step 2, the sheet-like composite layer (11) and the long composite layer (12) are immersed in a 0.4 mg / mL collagen solution and a collagen solution containing 30% nano-hydroxyapatite, respectively, and the upper and lower spacings between the immersion liquid surface and the braided body are 0.5-1.0 mm; in step 3, the composite body is pre-frozen at -20°C for 2 hours and freeze-dried at -50°C for 36 hours in sequence, and the gradient cooling inhibits the disordered growth of ice crystals, so that the sponge forms open pores with uniform pore size, the porosity of the sheet-like composite layer (11) is ≥80%, and the porosity of the long composite layer (12) is ≥60%, thereby ensuring the bidirectional migration of inflammatory cells and osteoblasts.

[0044] In another embodiment, the immersion process conditions in step 2) are: solution concentration is 0.01-1 mg / mL, immersion temperature is 4-40°C, immersion time is 0.1-60 min, and the distance between the upper and lower interfaces of the braid and the solution surface during immersion is 0.1-3 mm.

[0045] In step 2, the impregnation solution of the sheet composite layer (11) is a 0.5 mg / mL gelatin solution (pH=7.2), the impregnation temperature is 25°C, the impregnation time is 10 min, the distance between the braided body and the upper liquid level is 0.3 mm, and the distance between the lower liquid level is 0.8 mm; the distance regulates the capillary adsorption direction of the solution so that the gelatin mainly infiltrates the bottom of the braided body to form an asymmetric composite structure; the impregnation solution of the long strip composite layer (12) is a gelatin solution containing 15% nano-hydroxyapatite, the impregnation temperature is 40°C, the impregnation time is 5 min, and the distance between the upper and lower liquid levels is 0.1 mm; short-term high-temperature impregnation promotes the rapid adsorption of minerals on the surface of gelatin fibers and combines with the latter through hydrogen bonds, and the process parameters match the fiber swelling rate and mineral loading efficiency.

[0046] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this profession can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A composite stent for rotator cuff repair, characterized in that: include: The sheet-like composite layer is formed by a composite of a synthetic polymer braided body and a natural polymer sponge, wherein the synthetic polymer braided body is formed by a warp knitting or weft knitting process; The long strip composite layer is composited by a synthetic polymer braid and a natural polymer sponge containing nano-hydroxyapatite, and the long strip composite layer is connected to the edge of the sheet composite layer by warp knitting or weft knitting; The width of the long composite layer is 0.08-3 mm, and the width ratio of the sheet composite layer to the long composite layer in the connection area is (5:1)-(10:1).

2. The composite stent for rotator cuff repair according to claim 1, characterized in that: The synthetic polymer braided body material is selected from at least one of polyethylene terephthalate, polypropylene, polyethylene, polydioxanone, polydioxanone, polycaprolactone, poly-L-lactide, and polyglycolic acid.

3. The composite stent for rotator cuff repair according to claim 1, characterized in that: The raw materials of the natural polymer sponge are animal-derived collagen, recombinant collagen, gelatin, chitosan or silk fibroin.

4. The composite stent for rotator cuff repair according to claim 1, characterized in that: The mass proportion of nano-hydroxyapatite in the long composite layer is 0.5%-50% of the natural polymer material.

5. The composite stent for rotator cuff repair according to claim 1, characterized in that: The thickness of the sheet-like composite layer is 0.08-3 mm, and the thickness of the long strip composite layer is 0.08-3 mm.

6. The composite stent for rotator cuff repair according to claim 1, characterized in that: The strip composite layer and the sheet composite layer are woven and connected by the same synthetic polymer material, and the difference in yarn diameter between the two is ≤0.2mm.

7. The composite stent for rotator cuff repair according to claim 1, characterized in that: The spacing between adjacent long composite layers is 0.1–3 cm.

8. The composite stent for rotator cuff repair according to claim 1, characterized in that: In the natural polymer solution containing nano-hydroxyapatite, the nano-hydroxyapatite is loaded on the natural polymer network by physical adsorption or chemical bonding.

9. A method for preparing a composite stent for rotator cuff repair according to any one of claims 1 to 8, characterized in that: The following steps are involved: 1) Weaving the synthetic polymer woven bodies of the sheet-like composite layer and the long composite layer respectively, and connecting the long composite layer to the edge of the sheet-like composite layer by warp knitting or weft knitting; 2) immersing the sheet-shaped composite layer in a natural polymer solution, and immersing the long strip composite layer in a natural polymer solution containing nano-hydroxyapatite; 3) The impregnated composite layer is pre-frozen and freeze-dried, the pre-freezing temperature is -20°C to -50°C, and the freeze-drying time is 24-72h.

10. The preparation method according to claim 9, characterized in that: The immersion process conditions in step 2) are: solution concentration of 0.01-1 mg / mL, immersion temperature of 4-40°C, immersion time of 0.1-60 min, and the distance between the upper and lower interfaces of the braid and the solution surface during immersion is 0.1-3 mm.

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