A degradable tissue engineering labrum scaffold and its preparation method

Abstract

The present invention discloses a degradable tissue engineering labrum scaffold and a preparation method thereof. The scaffold uses a degradable polymer and an inorganic component as raw materials. Based on the melt electrostatic spinning process, the molten raw materials are stretched into fibers under the stretching effect of the electric field and the airflow field. The fibers are attached to a receiving roller to obtain highly oriented fiber bundles or fiber membranes. The fiber bundles or fiber membranes are loaded with polylactic-co-glycolic acid (PLGA) microspheres containing the small molecule drug bergenin and transforming growth factor β1 by spraying or soaking. The oriented fiber bundles or oriented fiber membranes after loading are curled to obtain oriented fiber aggregates. The obtained oriented fiber aggregates are placed in a pre-made mold for shaping, and the labrum scaffold is obtained after a period of time. The labrum scaffold prepared by the present invention has the advantages of bionic structure, solvent-free, high strength and good biocompatibility. It imitates the basic structure of the natural labrum composed of highly oriented circumferentially running collagen fiber bundles and has high tensile strength.

Description

Technical Field

[0001] The present invention belongs to the technical field of tissue engineering, and in particular relates to a degradable tissue engineering labrum scaffold and a preparation method thereof. Background Art

[0002] The hip joint is a ball-and-socket joint consisting of the femoral head and acetabulum. The acetabulum rim of the hip joint contains a fibrous cartilage ring called the glenoid labrum, which is crucial for hip joint stability and sealing. Degeneration or damage to the glenoid labrum can lead to hip instability and cartilage degradation, which can then develop into secondary osteoarthritis. Therefore, repairing or reconstructing the glenoid labrum is crucial to restore biomechanical function and protect the hip joint.

[0003] The current autologous and allogeneic transplantation techniques used for acetabular labrum repair have limitations. They cannot fully restore the morphology, structure, and mechanical properties of natural labrum tissue, and may cause a series of postoperative symptoms, such as insufficient labrum size, damage, surgical debridement, calcification, flattening, etc. In addition, in young patients, the surgery may fail due to the high mobility of young patients.

[0004] Tissue engineering technology provides a better option for repairing labral tissue, and biomaterials with good biocompatibility and degradability can be used in surgery. Melt electrospinning is a special fiber manufacturing process that uses polymer melt to perform jet spinning in a strong electric field. Under the action of the electric field, the droplet at the needle tip changes from a spherical shape to a conical shape, and fiber filaments are extended from the tip of the cone. This method can produce polymer filaments with nanometer diameters. Compared with traditional technologies, tissue engineering technology based on melt electrospinning can imitate the morphology, structure and mechanical properties of the natural labrum, that is, annular, composed of highly oriented circumferential fiber bundles, and therefore has strong circumferential tensile strength. Summary of the Invention

[0005] The purpose of the present invention is to provide a degradable tissue engineering labrum scaffold and a preparation method thereof, so as to imitate the morphology, structure and mechanical properties of natural labrum tissue.

[0006] The technical solution of the present invention is as follows: using degradable polymers and inorganic components as raw materials, based on the melt electrospinning process, the molten raw materials are stretched into fibers under the stretching effect of the electric field and the air flow field, and the fibers are attached to the receiving roller to obtain highly oriented fiber bundles or fiber membranes. By spraying or soaking, the fiber bundles or fiber membranes are loaded with polylactic acid-glycolic acid copolymer (PLGA) microspheres containing the small molecule drug kartogenin (KGN) and transforming growth factor β1 (TGF-β1). The loaded oriented fiber bundles or oriented fiber membranes are curled to obtain oriented fiber aggregates. The obtained oriented fiber aggregates are placed in a pre-made mold for shaping, and after a period of time, the labrum scaffold is obtained.

[0007] The present invention provides a degradable tissue engineering labrum scaffold. The raw materials include degradable organic polymers and inorganic components. The degradable polymers include one or more of polycaprolactone (PCL), polylactic acid (PLA), polylactic acid-glycolic acid copolymer (PLGA), polyethylene glycol (PEG), polybutylene adipate / terephthalate (PBAT), polybutylene succinate terephthalate (PBST), β-hydroxybutyrate and β-hydroxyvalerate copolymer (PHBV), polyglycolic acid (PGA), chitosan and its derivatives, and bacterial cellulose. The inorganic components include one or more of hydroxyapatite, tricalcium phosphate, and bioactive glass. The inorganic components can promote the repair of defective tissue, and the mass ratio of the inorganic components to the degradable organic polymers is 0 to 1 / 5.

[0008] The present invention provides a degradable tissue engineering labrum scaffold, wherein the highly oriented fiber bundle or fiber membrane and the melt electrospun fiber cannot be too thin, otherwise the mechanical properties will be significantly reduced and the preparation will be difficult. At the same time, the melt electrospun fiber cannot be too thick, otherwise the cell adhesion ability will be weakened after implantation in the body. The fiber diameter distribution is selected to be 300nm~5μm, preferably 800nm~2μm. The orientation of the highly oriented fiber cannot be too poor, otherwise it will lead to the inability of cells to proliferate in a specific direction after implantation in the body, differentiate into labrum tissue and the tensile properties will also be reduced. At the same time, the fiber cannot be completely oriented, otherwise the fibers cannot form a film between each other, affecting subsequent preparation. The oriented fiber angle is selected to be -30°~30°, preferably -10°~10°.

[0009] The present invention provides a degradable tissue engineering labrum scaffold. The scaffold has an arc-shaped shape and a nearly right-angled triangle cross-section. The outer diameter of the ring is between 28 and 32 mm, the base of the right-angled triangle is between 2.5 and 2.8 mm, the height is between 3 and 3.2 mm, and the scaffold weighs 200 to 250 mg. In actual use, the arc-shaped scaffold can be cut to the appropriate size according to the defect size.

[0010] The present invention provides a degradable tissue engineering labrum scaffold. The porosity of the oriented fiber aggregate after being molded cannot be too large, otherwise it will lead to a decrease in mechanical properties. At the same time, the porosity cannot be too small, otherwise it will lead to a decrease in cell expansion and migration space, a decrease in metabolic efficiency, and is not conducive to cell proliferation and differentiation. The scaffold porosity is selected to be 40% to 70%, preferably 50% to 60%.

[0011] The present invention provides a degradable tissue engineering labrum scaffold. The molding die is a common matching structure of upper and lower dies. The materials used are not particularly limited and can be plastic or metal. The manufacturing process is not particularly limited and can be 3D printing or CNC machine processing.

[0012] The present invention provides a degradable tissue engineering labrum scaffold, the preparation method of which comprises the following steps:

[0013] (1) After drying and premixing, the organic polymer and the inorganic component are melt-blended by an extruder, a torque rheometer, or an internal mixer, and then granulated by a granulator to obtain a blended raw material.

[0014] (2) drying the blended raw materials to obtain spinning raw materials, adding the spinning raw materials to a melt electrospinning device for spinning to prepare an oriented fiber bundle or an oriented fiber film having a fiber diameter in the range of 300 nm to 5 μm;

[0015] (3) Cut the fiber bundle or fiber membrane to the required length along the orientation direction, which is the length obtained by multiplying the diameter corresponding to the arc of the labrum support by π. Sterilize the fiber bundle or fiber membrane under ultraviolet light for 2 to 6 hours per side, and treat the fiber bundle or fiber membrane with a liquid containing 10 mg / mL PLGA microspheres by spraying or immersing. Let it stand at 4°C for 24 hours to complete the loading of PLGA microspheres. Then, curl the oriented fiber bundle or oriented fiber membrane loaded with microspheres to obtain an aggregate of oriented fibers.

[0016] (4) Place the obtained oriented fiber aggregate into a pre-made arc-shaped mold, close the upper and lower molds, and apply a downward pressure of 20 to 30N. Let it stand at 4°C for 8 to 24 hours, remove the bracket from the mold, and obtain the labrum bracket.

[0017] The present invention provides a method for preparing a degradable tissue engineering labrum scaffold. The melt electrospinning process has the following spinning parameters according to different spinning raw materials: a die temperature of 120 to 300°C, a spinning voltage of 30 to 55 kV, a receiving distance of 10 to 50 cm, and a collection drum speed of 2000 to 5000 r / min.

[0018] The present invention provides a degradable tissue engineering labrum scaffold and a preparation method thereof, which has the following main advantages and functions:

[0019] (1) The labrum scaffold is prepared by melt electrospinning. The prepared labrum scaffold has the advantages of bionic structure, solvent-free, high strength and good biocompatibility. It avoids the problems of traditional labrum scaffold preparation technology such as environmental pollution, poor biocompatibility, and solution electrospinning with toxic solvents that are difficult to remove.

[0020] (2) The labrum scaffold is in the shape of a ring with a right triangle cross section. The fiber orientation direction is along the circumference of the ring and is loaded with PLGA microspheres containing small molecule drugs KGN and TGF-β1. It mimics the basic structure of the natural labrum composed of highly oriented circumferential collagen fiber bundles and has high tensile strength.

[0021] (3) The labrum scaffold can be completely degraded within 6 to 9 months after being implanted in the human body, avoiding foreign body reaction and secondary surgery. The degradation rate of the labrum scaffold can be controlled by changing the ratio of the matrix material. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of a degradable tissue engineering labrum scaffold of the present invention;

[0023] Figure 2 Schematic diagram of a forming mold for a degradable tissue engineering labrum scaffold according to the present invention, (a) front view, (b) top view, (c) axonometric view;

[0024] Figure 3 This is an electron microscope image of a fiber membrane used in a degradable tissue engineering labrum scaffold of the present invention;

[0025] Figure 4 This is an electron microscope image of a PLGA microsphere-loaded fiber membrane used in a degradable tissue engineering labrum scaffold of the present invention;

[0026] Figure 5 This is a graph of the in vitro release of KGN drug from a degradable tissue engineering labrum scaffold of the present invention over 15 days.

[0027] In the figure: 1—upper mold; 2—lower mold. DETAILED DESCRIPTION

[0028] The present invention is further described below with reference to specific examples, but the present invention is not limited to the following examples. The methods described are conventional methods unless otherwise specified. The raw materials described can be obtained from public commercial channels unless otherwise specified.

[0029] A degradable tissue engineering labrum scaffold is provided. The labrum scaffold is arc-shaped, with a cross-section that is a nearly right-angled triangle with an angle of 80° to 110°. The outer diameter of the arc is 28mm to 32mm. The base length of the nearly right-angled triangle is between 2.5mm and 2.8mm, and the height is between 3mm and 3.2mm. The scaffold mass is between 200mg and 250mg, and the porosity is between 40% and 70%, preferably 50% to 60%. In actual use, the scaffold can be cut according to the size of the defect. The scaffold is a stack of highly oriented degradable fiber bundles or fiber membranes, with the orientation direction being the tangent direction of the arc. PLGA microspheres containing the small molecule drug KGN and TGF-β1 are evenly loaded between the oriented fiber bundles or fiber membranes.

[0030] Example 1

[0031] The present invention provides a degradable tissue engineering labrum scaffold as follows Figure 1The preparation method includes: (1) first preparing spinning raw materials, putting polycaprolactone (PCL) and tricalcium phosphate into an internal mixer after drying and premixing for melt blending, with a mass ratio of 9:1, parameters of 60℃, 60r / min, and granulating through a granulator; (2) drying the obtained blended raw materials, adding the dried raw materials into a melt electrospinning device for spinning, and the spinning raw materials are melted and extruded into the electrospinning die through an extruder, forming fibers under the action of electric field force and air flow field drawing, and depositing them on the high-speed rotating receiving roller fibers to prepare oriented fiber membranes, the die temperature is 200℃, the spinning voltage is 45kV, the receiving distance is 10cm, the collection roller speed is 3000r / min, the running time is 7min, and the deposition morphology of the fiber membrane is as follows: Figure 3 (3) Cut the fiber membrane to the required length along the orientation direction of the fiber membrane, sterilize the fiber membrane under ultraviolet light for 2 hours on each side, and spray 10 mg / mL PLGA microsphere liquid on the sterilized fiber membrane for treatment. Let it stand at 4°C for 24 hours to complete the loading of PLGA microspheres. The morphology of the fiber membrane loaded with PLGA microspheres is as follows: Figure 4 (4) The oriented fiber membrane loaded with PLGA microspheres is curled to obtain an aggregate of oriented fibers, such as Figure 3 ; Place the obtained fiber aggregate into Figure 2 The upper mold 1 and the lower mold 2 were fixed together using screws and nuts in the groove of the upper mold 1 shown in the figure. The mold was allowed to stand at 4°C for 8 hours. The stent was taken out of the mold to obtain the labrum stent. The KGN drug release in vitro of the labrum stent for 15 days was as follows: Figure 5 shown.

[0032] Example 2

[0033] The present invention discloses a degradable tissue engineering labrum scaffold, and its preparation method comprises the following steps: (1) drying and pre-mixing polylactic acid (PLA) and hydroxyapatite, putting them into an internal mixer for melt blending, with a mass ratio of 4:1 and a parameter of 170°C, and granulating them through a granulator; (2) drying the obtained blended raw materials, adding the dried spinning raw materials into a melt electrospinning device for spinning, and extruding the spinning raw materials into an electrospinning die head through an extruder, forming fibers under the action of electric field force and air flow field stretching, and depositing them on a high-speed rotating receiving roller fiber to prepare an oriented fiber membrane, wherein the die head temperature is 220°C, the spinning voltage is 50kV, the receiving distance is 10cm, the collecting roller speed is 2500r / min, and the running time is 7min; (3) cutting the fiber membrane, cutting the required length along the orientation direction of the fiber membrane, sterilizing the fiber membrane under ultraviolet light for 2 hours per side, and soaking the sterilized fiber membrane in 10mg / m L of PLGA microsphere liquid is treated and allowed to stand at 4°C for 24 hours to complete the loading of PLGA microspheres; (4) the oriented fiber membrane loaded with PLGA microspheres is curled to obtain an aggregate of oriented fibers; the obtained fiber aggregate is placed in the groove of the upper mold 1, and the upper mold 1 and the lower mold 2 are fixed with screws and nuts, and allowed to stand at 4°C. After 12 hours, the bracket is taken out from the mold to obtain the labrum bracket.

[0034] The performance parameters of the stents obtained in Example 1 and Example 2 are shown in Table 1.

[0035] Table 1: Comparison of bracket performance parameters

[0036] sample Example 1 Example 2 Natural porcine labrum Average fiber fineness (μm) 2.4 1 — Tensile strength (MPa) 15.13 16.20 13.89 elastic modulus 46.6 52.2 15.1 Elongation at break (%) 92 63 50

Claims

1. A degradable tissue engineering labrum scaffold, characterized by: The labrum scaffold is arc-shaped, with a cross-section that is nearly a right triangle, an angle of 80°~110°, an outer diameter of the arc of 28 mm~32 mm, a base length of the nearly right triangle between 2.5 mm~2.8 mm, and a height between 3 mm~3.2 mm. The scaffold mass is 200~250 mg, and the porosity is 40%~70%. In actual use, it can be cut according to the size of the defect. The scaffold is a highly oriented biodegradable fiber bundle or fiber membrane stack, and the orientation direction is the tangent direction of the arc. Polylactic acid-glycolic acid copolymer microspheres containing the small molecule drug bergenin and transforming growth factor β1 are uniformly loaded between the oriented fiber bundles or fiber membranes; the diameter of the fibers or the fibers constituting the fiber bundles or fiber membranes is distributed between 300 nm~5 μm, and the angle of the fibers relative to the tangent of the arc of the arc-shaped scaffold is -30°. ~30°; the material of the degradable fiber bundle or fiber membrane is composed of a degradable biocompatible polymer and an inorganic component, and the mass ratio of the inorganic component to the degradable biocompatible polymer is in the range of 0~1 / 5; the degradable biocompatible polymer includes one or more blends of polycaprolactone (PCL), polylactic acid (PLA), polylactic acid-glycolic acid copolymer (PLGA), polyethylene glycol (PEG), polybutylene adipate / terephthalate (PBAT), polybutylene succinate terephthalate (PBST), β-hydroxybutyric acid and β-hydroxyvalerate copolymer (PHBV), polyglycolic acid (PGA), chitosan and its derivatives, and bacterial cellulose; the inorganic component includes one or more of hydroxyapatite, tricalcium phosphate and bioactive glass.

2. The degradable tissue engineering labrum scaffold according to claim 1, characterized in that: The diameter of the fibers or fibers constituting the fiber bundles or fiber membranes is distributed in the range of 800 nm to 2 μm, and the angle between the fibers and the tangent line of the arc of the arc-shaped support is in the range of -10° to 10°.

3. The method for preparing a degradable tissue engineering labrum scaffold according to claim 1, comprising the following steps: (1) After drying and premixing, the biodegradable biocompatible polymer and the inorganic component are melt-blended by an extruder, a torque rheometer, or an internal mixer, and then granulated by a granulator to obtain a blended raw material; (2) Drying the blended raw materials to obtain spinning raw materials, adding the spinning raw materials to a melt electrospinning device for spinning, and preparing an oriented fiber bundle or an oriented fiber film with a fiber diameter in the range of 300 nm to 5 μm; (3) Cut the required length along the orientation direction of the fiber bundle or fiber membrane. The length is the diameter of the labrum support arc multiplied by The obtained length is obtained, the fiber bundle or fiber membrane is sterilized under ultraviolet light for 2 to 6 hours per side, and the fiber bundle or fiber membrane is treated by spraying or immersing a liquid containing 10 mg / mL PLGA microspheres, and allowed to stand at 4°C for one day to complete the loading of PLGA microspheres. The oriented fiber bundle or oriented fiber membrane loaded with microspheres is then curled to obtain an aggregate of oriented fibers; (4) Place the obtained oriented fiber aggregate into a pre-made arc-shaped mold, close the upper and lower molds, and apply a downward pressure of 20 to 30N. Let it stand at 4°C for 8 to 24 hours, then remove the scaffold from the mold to obtain the labrum scaffold.

4. The method for preparing a degradable tissue engineering labrum scaffold according to claim 3, characterized in that: The melt electrospinning process has the following spinning parameters according to different spinning raw materials: die temperature of 120-300°C, spinning voltage of 30-55 kV, receiving distance of 10-50 cm, and collecting drum speed of 2000-5000 r / min.

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