Double-layer electrospinning tube for reducing tendon adhesion as well as preparation and application of double-layer electrospinning tube

Abstract

The invention provides an electrospinning double-layer tube for reducing tendon adhesion and preparation and application thereof, the electrospinning double-layer tube is composed of an inner layer and an outer layer, the inner layer is composed of a gelatin methacrylated derivative and polyvinyl alcohol, the outer layer is composed of a lactide-caprolactone copolymer, and the inner layer and the outer layer are electrospinning films prepared by an electrostatic spinning process. The electrospinning tube has excellent mechanical performance and a remarkable anti-adhesion effect, adhesion between tendons and surrounding tissues can be effectively reduced, the adhesion degree can be reduced to the level close to that of original tendons, postoperative functional recovery of patients is improved, and the electrospinning tube is remarkably superior to a pure PLCL tube in the prior art.

Description

Technical Field

[0001] The present invention belongs to the field of materials for medical devices, and particularly relates to an electrospun double-layer tube for reducing tendon adhesion, and its preparation and application. Background Art

[0002] Tendons are important tissues that connect muscles and bones. After tendon injury, adhesion usually occurs, resulting in abnormal connection between the tendon and surrounding tissues, and restricting the range of joint movement. The formation of this adhesion is due to the generation of fibrotic tissue between the tendon and surrounding tissues during the healing process, which further leads to dysfunction and pain, seriously affecting the quality of life of patients. Currently, the methods for reducing tendon adhesion clinically mainly include surgery and the use of physical barrier materials. Physical barrier materials can reduce the contact between the tendon and surrounding tissues to a certain extent, thereby reducing the occurrence of adhesion. However, the existing physical barrier materials have limited effects in reducing adhesion. Gelatin methacryloyl derivative (GelMA) is a multifunctional material with both biological activity, processability and biocompatibility, and it has excellent cell compatibility and degradability. Polyvinyl alcohol (PVA) is a biodegradable polymer with good processing properties. However, due to insufficient viscoelasticity and mechanical properties, methacryloyl derivative (GelMA) is prone to operation difficulties during the electrospinning process. Therefore, it usually needs to be combined with other polymers to improve the electrospinning performance.

[0003] Therefore, there is an urgent need to develop a composite material that can significantly reduce tendon adhesion and has excellent mechanical properties to solve the deficiencies in the existing technology and provide a better treatment plan for clinical tendon repair. Summary of the Invention

[0004] Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide an electrospun double-layer tube for reducing tendon adhesion, and its preparation and application. The electrospun double-layer tube of the present invention can reduce tendon adhesion and significantly improve the anti-adhesion effect.

[0005] To achieve the purpose of this invention, the following technical solutions are adopted:

[0006] On the one hand, the present invention provides an electrospun double-layer tube for reducing tendon adhesion. The electrospun double-layer tube is composed of an inner layer and an outer layer. The inner layer is composed of gelatin methacryloyl derivative (GelMA) and polyvinyl alcohol (PVA), and the outer layer is composed of poly(lactide-co-caprolactone) (PLCL). Both the inner layer and the outer layer are electrospun membranes prepared by the electrospinning process.

[0007] The electrospun tube of the present invention has excellent mechanical properties and remarkable anti-adhesion effects, can effectively reduce the adhesion between the tendon and surrounding tissues, can reduce the adhesion degree to a level close to that of the original tendon, improve the functional recovery of patients after surgery, and is significantly superior to the pure PLCL tube in the prior art.

[0008] Preferably, the weight-average molecular weight of the polyvinyl alcohol is 50,000 - 150,000 Da, such as 50,000 Da, 80,000 Da, 100,000 Da, 110,000 Da, 120,000 Da, 130,000 D, 140,000 Da or 150,000 Da.

[0009] In the present invention, polyvinyl alcohol within the range of the weight-average molecular weight is selected to ensure good spinning performance and moderate mechanical strength. PVA within this molecular weight range can provide good spinning performance, and at the same time has sufficient mechanical strength, being suitable for use as a film and fiber material. It has good spinnability and can form uniform fibers during the electrospinning process. For co-spinning with GelMA, it can ensure good fusion between layers.

[0010] Preferably, the weight-average molecular weight of the lactide-caprolactone copolymer is 50,000 - 200,000 Da, such as 50,000 Da, 60,000 Da, 80,000 Da, 100,000 Da, 110,000 Da, 120,000 Da, 130,000 D, 140,000 Da, 150,000 Da, 160,000 Da, 170,000 Da, 180,000 Da or 200,000 Da.

[0011] In the present invention, the lactide-caprolactone copolymer within the range of the weight-average molecular weight is selected to ensure sufficient mechanical properties and appropriate degradation rate. PLCL within this molecular weight range has good mechanical properties and degradation rate, and is applicable to biomedical applications such as tissue repair and anti-adhesion. PLCL needs to have sufficient mechanical strength to provide support, and at the same time the degradation rate should be moderate, so as to support tissue repair for a long time and reduce the occurrence of adhesion.

[0012] Preferably, the mass ratio of gelatin methacryloyl derivative (GelMA) to polyvinyl alcohol (PVA) in the inner layer is 1:1 - 1:10, such as 1:1, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5, 1:6, 1:7, 1:8, 1:9 or 1:10, etc.

[0013] In the present invention, GelMA mainly provides biocompatibility and degradation characteristics, while PVA mainly provides mechanical strength and solubility, making the fibers and membranes more stable. PVA can also enhance the spinning performance of the membranes, reduce the brittleness of GelMA, and endow the final structure with better mechanical properties. The addition of PVA helps to adjust the solution viscosity, making the fibers in the co-spinning process more uniform. A mass ratio of GelMA to PVA in the range of 1:1 - 1:10 can provide a balanced biocompatibility and mechanical properties, ensuring both the cross-linking ability and biodegradability of GelMA, and providing appropriate mechanical support and suitable spinning performance through PVA.

[0014] Preferably, the thickness of the inner layer is 0.05 - 0.5 mm, such as 0.05 mm, 0.08 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, or 0.5 mm.

[0015] Preferably, the thickness of the outer layer is 0.05 - 0.5 mm, such as 0.05 mm, 0.08 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, or 0.5 mm.

[0016] On the other hand, the present invention provides a method for preparing the electrospun double-layer tube for reducing tendon adhesion as described above, and the preparation method includes the following steps:

[0017] (1) Using the PEG solution as the electrospinning solution, performing electrospinning to obtain a PEG electrospun membrane layer on the collecting rod;

[0018] (2) Using the solution containing gelatin methacryloylated derivative and polyvinyl alcohol as the electrospinning solution, performing electrospinning to obtain an inner layer on the PEG electrospun membrane layer;

[0019] (3) Using the lactide-caprolactone copolymer solution as the electrospinning solution, performing electrospinning to obtain an outer layer on the inner layer;

[0020] (4) Detaching the obtained electrospun membrane from the collecting rod with ethanol, and then performing heat setting to obtain the electrospun double-layer tube for reducing tendon adhesion.

[0021] In the present invention, the PEG solution is obtained by dissolving PEG in chloroform at room temperature.

[0022] Preferably, the mass percentage concentration of the PEG solution is 20 - 40%, such as 20%, 23%, 25%, 28%, 30%, 33%, 35%, 38%, or 40%.

[0023] Preferably, the collecting rod is a stainless steel tube with a diameter of 1 - 10 mm (such as 1 mm, 3 mm, 5 mm, 8 mm, or 10 mm).

[0024] Preferably, in the electrospinning of step (1), the injection rate of the electrospinning solution is 10 - 40 μl / min (such as 10 μl / min, 15 μl / min, 18 μl / min, 20 μl / min, 25 μl / min, 28 μl / min, 30 μl / min, 35 μl / min, 38 μl / min or 40 μl / min), and the applied voltage is 10 - 35 kV (such as 10 kV, 15 kV, 20 kV, 25 kV, 30 kV or 35 kV).

[0025] Preferably, in the electrospinning of step (1), the rotational receiving speed of the collecting rod is 500 - 2000 r / h (such as 500 r / h, 800 r / h, 1000 r / h, 1200 r / h, 1500 r / h, 1800 r / h or 2000 r / h), and the receiving distance is 10 - 40 cm (such as 10 cm, 15 cm, 20 cm, 25 cm, 30 cm, 35 cm or 40 cm).

[0026] Preferably, the electrospinning time in step (1) is 5 - 20 min, such as 5 min, 8 min, 10 min, 15 min, 18 min or 20 min.

[0027] Preferably, the solution containing the gelatin methacrylated derivative and polyvinyl alcohol in step (2) is prepared by dissolving the gelatin methacrylated derivative and polyvinyl alcohol in ultrapure water.

[0028] Preferably, in the solution containing the gelatin methacrylated derivative and polyvinyl alcohol in step (2), the total mass percentage concentration of the gelatin methacrylated derivative and polyvinyl alcohol is 1 - 10%, such as 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%.

[0029] Preferably, in the electrospinning of step (2), the injection rate of the electrospinning solution is 10 - 40 μl / min (such as 10 μl / min, 15 μl / min, 18 μl / min, 20 μl / min, 25 μl / min, 28 μl / min, 30 μl / min, 35 μl / min, 38 μl / min or 40 μl / min), and the applied voltage is 10 - 35 kV (such as 10 kV, 15 kV, 20 kV, 25 kV, 30 kV or 35 kV).

[0030] Preferably, the rotational receiving speed of the collecting rod in the electrospinning in step (2) is 500 - 2000 r / h (such as 500 r / h, 800 r / h, 1000 r / h, 1200 r / h, 1500 r / h, 1800 r / h or 2000 r / h), and the receiving distance is 10 - 40 cm (such as 10 cm, 15 cm, 20 cm, 25 cm, 30 cm, 35 cm or 40 cm).

[0031] Preferably, the electrospinning time in step (2) is 20 - 80 min, such as 20 min, 30 min, 40 min, 50 min, 60 min, 70 min or 80 min.

[0032] Preferably, the lactide - caprolactone copolymer solution in step (3) is obtained by dissolving the lactide - caprolactone copolymer in a solvent.

[0033] Preferably, the solvent is selected from any one or a combination of at least two of hexafluoroisopropanol (HFIP), dichloromethane (DCM), chloroform (CHCl3) or acetone (Acetone), and hexafluoroisopropanol is further preferred.

[0034] Preferably, the mass percentage concentration of the lactide - caprolactone copolymer solution in step (3) is 5 - 25%, such as 5%, 10%, 13%, 15%, 18%, 20%, 22% or 25%.

[0035] Preferably, the injection speed of the electrospinning solution in the electrospinning in step (3) is 10 - 40 μl / min (such as 10 μl / min, 15 μl / min, 18 μl / min, 20 μl / min, 25 μl / min, 28 μl / min, 30 μl / min, 35 μl / min, 38 μl / min or 40 μl / min), and the applied voltage is 10 - 35 kV (such as 10 kV, 15 kV, 20 kV, 25 kV, 30 kV or 35 kV).

[0036] Preferably, the rotational receiving speed of the collecting rod in the electrospinning in step (3) is 500 - 2000 r / h (such as 500 r / h, 800 r / h, 1000 r / h, 1200 r / h, 1500 r / h, 1800 r / h or 2000 r / h), and the receiving distance is 10 - 40 cm (such as 10 cm, 15 cm, 20 cm, 25 cm, 30 cm, 35 cm or 40 cm).

[0037] Preferably, the electrospinning time in step (3) is 20 - 80 min, such as 20 min, 30 min, 40 min, 50 min, 60 min, 70 min or 80 min.

[0038] In the present invention, the PEG electrospun membrane layer obtained by electrospinning can be dissolved in ethanol at 40 - 60% (such as 40%, 45%, 48%, 50%, 55%, 58% or 60%). Therefore, in the present invention, ethanol is used to detach the obtained electrospun membrane from the collecting rod, and in this process, the PEG electrospun membrane layer is removed.

[0039] Preferably, the temperature of the heat setting in step (4) is 25 - 40°C (such as 25°C, 28°C, 30°C, 35°C, 38°C or 40°C), and the time of the heat setting is 30 - 80 min (such as 30 min, 40 min, 50 min, 60 min, 70 min or 80 min).

[0040] On the other hand, the present invention provides the application of the electrospun double-layer tube for reducing tendon adhesion as described above in tendon repair materials.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] (1) The electrospun double-layer tube of the present invention is designed as a double-layer structure, and the operability and applicability are improved through reasonable material combination. When in use, the electrospun tube can be flipped to ensure that the GelMA / PVA layer directly contacts the external tissue of the tendon, while the PLCL layer faces the tendon body to provide support for the tendon. This double-layer structure also allows for better adaptation to complex joint parts during tendon transplantation or repair surgery.

[0043] (2) The inner layer raw materials of the electrospun double-layer tube for reducing tendon adhesion are GelMA and PVA. GelMA (gelatin methacryloylated derivative) is a water-soluble biomaterial generated by chemically modifying gelatin, and it has extensive applications in biomedical and tissue engineering. The combination of GelMA and PVA not only supports cell adhesion and growth, but also inhibits the inflammatory response and reduces the risk of fibrosis. This combination enables the electrospun tube to be placed in the body for a long time without causing rejection reactions, and at the same time can promote the natural healing process of the tendon.

[0044] (3) The outer layer of the electrospun double-layer tube for reducing tendon adhesion is an oriented PLCL electrospun layer. The oriented fibers provide excellent tensile resistance along the fiber direction by simulating the fiber arrangement structure of natural tendons, ensuring the mechanical support at the postoperative repair site. Its orientation can also guide the adhesion, proliferation and arrangement of myofibroblasts, promote the orderly deposition of collagen fibers, and thus accelerate the functional regeneration of the new tendon. In addition, the oriented fiber layer reduces the formation of random scar tissue, effectively reduces the risk of postoperative adhesion, and provides double guarantees of dynamic support and tissue guidance for tendon repair.

[0045] (4) The electrospun double-layer tube for reducing tendon adhesion is prepared by an electrospinning process. The prepared electrospun tube has good biocompatibility, reduces immune rejection reactions, and can be completely degraded in the human body. The surface of the electrospun tube has a high porosity, which helps to promote the exchange of nutrients and metabolic wastes, and at the same time provides suitable wetness to support cell adhesion and proliferation. The high porosity enables the electrospun tube to effectively accommodate growth factors and nutrients during the repair process and maintain the balance of the tendon repair environment. By regulating the content of GelMA / PVA, the hydrophilicity and degradation rate of the electrospun tube can be adjusted, thereby adapting to the rate of tendon tissue regeneration. At the same time, the GelMA / PVA layer significantly improves the tensile resistance of the electrospun tube. This characteristic makes the electrospun tube more suitable for operation during surgery, easy to be stretched and wrapped around the tendon, and reduces the risk of tube breakage. Description of the Drawings

[0046] Figure 1 This is a photograph of the electrospun double-layer tube of the present invention.

[0047] Figure 2 This is an SEM image of the electrospun fibers of the electrospun double-layer tube of the present invention. Detailed Embodiments

[0048] The technical solutions of the present invention will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only for helping to understand the present invention and should not be regarded as specific limitations on the present invention.

[0049] The sources of the materials used in the following examples and comparative examples are as follows:

[0050] PLCL was purchased from Macklin, poly(L-lactide-co-ε-caprolactone), synthesized by copolymerization of two monomers, L-lactide and ε-caprolactone, with a monomer molar ratio of 70:30;

[0051] Gelatin methacryloyl derivative (GelMA): purchased from Sigma-Aldrich, DiscreteGelMA, product number 938416;

[0052] Polyvinyl alcohol (PVA) was purchased from Sigma-Aldrich, product number 341584, Mw 89,000 - 98,000;

[0053] PEG was purchased from Sigma-Aldrich, product number 81310, Mn 35,000;

[0054] This embodiment provides an electrospun double-layer tube for reducing tendon adhesion, and its preparation method includes the following steps:

[0055] (1) First, prepare the electrospinning solution: Dissolve PLCL in hexafluoroisopropanol (HFIP), and stir the solution at room temperature until it is completely dissolved to obtain a solution with a mass percentage concentration of 16%. Dissolve gelatin methacryloyl derivative (GelMA) and polyvinyl alcohol (PVA) in ultrapure water at a mass ratio of (1:3) to prepare a 5 wt% solution. Dissolve PEG in chloroform at room temperature to obtain a 30 wt% solution.

[0056] (2) During the electrospinning process, use a stainless steel tube with a diameter of 1 mm as the collecting rod. Inject the PEG solution into the syringe, and perform electrospinning under the action of a propulsion pump. Adjust the injection speed to 15 μl / min, the applied voltage to 15 kV, use a rotating stainless steel tube to receive the electrospun fibers, adjust the rotating receiving speed to 600 r / h, the receiving distance to 20 cm, and electrospin for 5 min.

[0057] (3) Replace the syringe, inject the GelMA / PVA solution into the syringe, and perform secondary electrospinning under the action of a propulsion pump. Adjust the injection speed to 20 μl / min, the applied voltage to 25 kV, use a rotating stainless steel tube to receive the electrospun fibers, adjust the rotating receiving speed to 600 r / h, the receiving distance to 18 cm, and electrospin for 40 min to obtain a spun film with a thickness of 20.7 μm.

[0058] (4) Replace the syringe, inject the PLCL solution into the syringe, and perform electrospinning again under the action of a propulsion pump. Adjust the injection speed to 30 μl / min, the applied voltage to 30 kV, use a rotating stainless steel tube to receive the electrospun fibers, adjust the rotating receiving speed to 1500 r / h, the receiving distance to 26 cm, and electrospin for 40 min to obtain a spun film with a thickness of 97.6 μm.

[0059] (5) The PEG layer is easily soluble in 50% ethanol. Therefore, after electrospinning is completed, use ethanol to detach the tube from the metal rod. After the electrospinning tube is detached from the metal rod, perform heat setting at a temperature of 30 °C for 30 min to obtain a double-layer electrospinning tube for reducing tendon adhesion.

[0060] The photograph of the double-layer electrospinning tube prepared in this example is as Figure 1 shown, Figure 2 which is the SEM (Phenom Pro model: Pro) image of the electrospun fibers of the double-layer tube.

[0061] Example 2

[0062] This example provides an electrospun double-layer tube for reducing tendon adhesion, and its preparation method includes the following steps:

[0063] (1) First, prepare the electrospinning solution: Dissolve PLCL in hexafluoroisopropanol (HFIP), and stir the solution at room temperature until it is completely dissolved to obtain a solution with a mass percentage concentration of 10%. Dissolve gelatin methacryloyl derivative (GelMA) and polyvinyl alcohol (PVA) in ultrapure water at a mass ratio of (1:1) to prepare a 5 wt% solution. Dissolve PEG in chloroform at room temperature to obtain a 30 wt% solution.

[0064] (2) During the electrospinning process, use a stainless steel tube with a diameter of 1 mm as the collecting rod. Inject the PEG solution into the syringe, and perform electrospinning under the action of a syringe pump. Adjust the injection speed to 25 μl / min, the applied voltage to 25 kV, use a rotating stainless steel tube to receive the electrospun fibers, adjust the rotating receiving speed to 500 r / h, the receiving distance to 30 cm, and electrospin for 10 min.

[0065] (3) Replace the syringe, inject the GelMA / PVA solution into the syringe, and perform secondary electrospinning under the action of a syringe pump. Adjust the injection speed to 40 μl / min, the applied voltage to 35 kV, use a rotating stainless steel tube to receive the electrospun fibers, adjust the rotating receiving speed to 800 r / h, the receiving distance to 30 cm, and electrospin for 50 min to obtain a spun film with a thickness of 57.6 μm.

[0066] (4) Replace the syringe, inject the PLCL solution into the syringe, and perform electrospinning again under the action of a syringe pump. Adjust the injection speed to 40 μl / min, the applied voltage to 35 kV, use a rotating stainless steel tube to receive the electrospun fibers, adjust the rotating receiving speed to 2000 r / h, the receiving distance to 40 cm, and electrospin for 70 min to obtain a spun film with a thickness of 150.2 μm.

[0067] (5) The PEG layer is easily soluble in 50% ethanol. Therefore, after electrospinning is completed, use ethanol to detach the tube from the metal rod. After the electrospinning tube is detached from the metal rod, perform heat setting at a temperature of 30 °C for 30 min to obtain a double-layer electrospun tube that reduces tendon adhesion.

[0068] Example 3

[0069] This example provides a double-layer electrospun tube for reducing tendon adhesion, and its preparation method includes the following steps:

[0070] (1) First, prepare the electrospinning solution: Dissolve PLCL in hexafluoroisopropanol (HFIP), and stir the solution at room temperature until it is completely dissolved to obtain a solution with a mass percentage concentration of 25%. Dissolve gelatin methacryloyl derivative (GelMA) and polyvinyl alcohol (PVA) in ultrapure water at a mass ratio of (1:10) to prepare a 10 wt% solution. Dissolve PEG in chloroform at room temperature to obtain a 30 wt% solution.

[0071] (2) During the electrospinning process, use a stainless steel tube with a diameter of 1 mm as the collecting rod. Inject the PEG solution into the syringe, and perform electrospinning under the action of a syringe pump. Adjust the injection speed to 10 μl / min, the applied voltage to 20 kV, use a rotating stainless steel tube to collect the electrospun fibers, adjust the rotating collection speed to 1000 r / h, the receiving distance to 20 cm, and electrospin for 20 min.

[0072] (3) Replace the syringe, inject the GelMA / PVA solution into the syringe, and perform secondary electrospinning under the action of a syringe pump. Adjust the injection speed to 40 μl / min, the applied voltage to 15 kV, use a rotating stainless steel tube to collect the electrospun fibers, adjust the rotating collection speed to 1000 r / h, the receiving distance to 10 cm, and electrospin for 30 min to obtain a spun film with a thickness of 70.4 μm.

[0073] (4) Replace the syringe, inject the PLCL solution into the syringe, and perform electrospinning again under the action of a syringe pump. Adjust the injection speed to 30 μl / min, the applied voltage to 30 kV, use a rotating stainless steel tube to collect the electrospun fibers, adjust the rotating collection speed to 500 r / h, the receiving distance to 10 cm, and electrospin for 60 min to obtain a spun film with a thickness of 180.6 μm.

[0074] (5) The PEG layer is easily soluble in 50% ethanol. Therefore, after electrospinning is completed, use ethanol to detach the tube from the metal rod. After the electrospinning tube is detached from the metal rod, perform heat setting at a temperature of 30 °C for 30 min to obtain a double-layer electrospun tube for reducing tendon adhesion.

[0075] Example 4

[0076] This example provides an electrospun double-layer tube for reducing tendon adhesion, and its preparation method includes the following steps:

[0077] (1) First, prepare the electrospinning solution: Dissolve PLCL in hexafluoroisopropanol (HFIP), stir the solution at room temperature until it is completely dissolved to obtain a solution with a mass percentage concentration of 10%. Dissolve gelatin methacryloyl derivative (GelMA) and polyvinyl alcohol (PVA) in ultrapure water at a mass ratio of (1:5) to prepare a 15 wt% solution. Dissolve PEG in chloroform at room temperature to obtain a 30 wt% solution.

[0078] (2) During the electrospinning process, use a stainless steel tube with a diameter of 1 mm as the collecting rod. Inject the PEG solution into the syringe and perform electrospinning under the action of a syringe pump. Adjust the injection speed to 10 μl / min, the applied voltage to 40 kV, use a rotating stainless steel tube to receive the electrospun fibers, adjust the rotating receiving speed to 500 r / h, the receiving distance to 40 cm, and electrospin for 20 min.

[0079] (3) Replace the syringe, inject the GelMA / PVA solution into the syringe, and perform secondary electrospinning under the action of a syringe pump. Adjust the injection speed to 40 μl / min, the applied voltage to 35 kV, use a rotating stainless steel tube to receive the electrospun fibers, adjust the rotating receiving speed to 500 r / h, the receiving distance to 10 cm, and electrospin for 70 min to obtain a spun film with a thickness of 200.4 μm.

[0080] (4) Replace the syringe, inject the PLCL solution into the syringe, and perform electrospinning again under the action of a syringe pump. Adjust the injection speed to 40 μl / min, the applied voltage to 35 kV, use a rotating stainless steel tube to receive the electrospun fibers, adjust the rotating receiving speed to 800 r / h, the receiving distance to 25 cm, and electrospin for 70 min to obtain a spun film with a thickness of 155.3 μm.

[0081] (5) The PEG layer is easily soluble in 50% ethanol. Therefore, after electrospinning is completed, use ethanol to detach the tube from the metal rod. After the electrospinning tube is detached from the metal rod, perform heat setting at a temperature of 30 °C for 30 min to obtain a double-layer electrospun tube that reduces tendon adhesion.

[0082] Example 5

[0083] This example provides an electrospun double-layer tube that reduces tendon adhesion, and its preparation method includes the following steps:

[0084] (1) First, prepare the electrospinning solution: Dissolve PLCL in hexafluoroisopropanol (HFIP), and stir the solution at room temperature until it is completely dissolved to obtain a solution with a mass percentage concentration of 16%. Dissolve gelatin methacryloyl derivative (GelMA) and polyvinyl alcohol (PVA) in ultrapure water at a mass ratio of (1:8) to prepare a 15 wt% solution. Dissolve PEG in chloroform at room temperature to obtain a 30 wt% solution.

[0085] (2) During the electrospinning process, use a stainless steel tube with a diameter of 1 mm as the collecting rod. Inject the PEG solution into the syringe, and perform electrospinning under the action of a syringe pump. Adjust the injection speed to 25 μl / min, the applied voltage to 25 kV, use a rotating stainless steel tube to collect the electrospun fibers, adjust the rotating receiving speed to 800 r / h, the receiving distance to 20 cm, and electrospin for 10 min.

[0086] (3) Replace the syringe, inject the GelMA / PVA solution into the syringe, and perform secondary electrospinning under the action of a syringe pump. Adjust the injection speed to 20 μl / min, the applied voltage to 25 kV, use a rotating stainless steel tube to collect the electrospun fibers, adjust the rotating receiving speed to 2000 r / h, the receiving distance to 10 cm, and electrospin for 30 min to obtain a spun film with a thickness of 57.8 μm.

[0087] (4) Replace the syringe, inject the PLCL solution into the syringe, and perform electrospinning again under the action of a syringe pump. Adjust the injection speed to 10 μl / min, the applied voltage to 20 kV, use a rotating stainless steel tube to collect the electrospun fibers, adjust the rotating receiving speed to 500 r / h, the receiving distance to 10 cm, and electrospin for 40 min to obtain a spun film with a thickness of 43.2 μm.

[0088] (5) The PEG layer is easily soluble in 50% ethanol. Therefore, after electrospinning, use ethanol to detach the tube from the metal rod. After the electrospinning tube is detached from the metal rod, perform heat setting at a temperature of 30 °C for 30 min to obtain a double-layer electrospun tube that reduces tendon adhesion.

[0089] Comparative Example 1

[0090] The difference from Example 1 is only that in step (1), dissolve the gelatin methacryloyl derivative (GelMA) in ultrapure water to prepare a 5 wt% solution, and use this GelMA solution for electrospinning in step (3). The other steps are the same as those in Example 1.

[0091] Comparative Example 2

[0092] The difference from Example 1 is only that in step (1), polyvinyl alcohol (PVA) is dissolved in ultrapure water to prepare a 5 wt% solution, and in step (3), this PVA solution is used for electrospinning, and the other steps are the same as those in Example 1.

[0093] Comparative Example 3

[0094] The difference from Example 1 is only that in step (1), gelatin methacryloylated derivative (GelMA) and polyvinyl alcohol (PVA) are dissolved in ultrapure water at a mass ratio of (2:1) to prepare a 5 wt% solution, and in step (3), this GelMA / PVA solution is used for electrospinning, and the other steps are the same as those in Example 1.

[0095] Comparative Example 4

[0096] The difference from Example 1 is only that in step (1), gelatin methacryloylated derivative (GelMA) and polyvinyl alcohol (PVA) are dissolved in ultrapure water at a mass ratio of (1:12) to prepare a 5 wt% solution, and in step (3), this PVA solution is used for electrospinning, and the other steps are the same as those in Example 1.

[0097] Performance tests were carried out on the double-layer electrospun tubes prepared in the above examples, and the test methods are as follows:

[0098] (1) Fiber pore size: It was measured by scanning electron microscopy (SEM). The prepared nanofiber scaffolds were cut into experimental samples with a length × width of 15 mm × 15 mm. Three samples were prepared for each group and placed on the microscope stage. The acceleration voltage was 10 kV, and the SEM image of the PLCL layer was taken. In order to measure the pore size, the pores of two diagonals were analyzed.

[0099] (2) Hydrophilicity: It was measured for the GelMA / PVA layer by a contact angle measuring instrument. The prepared composite nanofiber scaffolds were cut into experimental samples with a length × width of 10 mm × 50 mm. Three samples were prepared for each group of dressings. Static water contact angle tests were carried out at room temperature using a contact angle measuring instrument. The nanofiber scaffold sample to be tested was placed flat on the stage, and 10 μL of water droplets were dropped onto the test dressing to form a static fixed liquid droplet. At the 10th second when the water droplet contacted the sample surface, a photo was taken to record the contact angle. Three random points of each sample were measured and analyzed to evaluate the hydrophilicity of the nanofiber scaffold.

[0100] (3) Melting point: It was measured by differential scanning calorimetry (DSC). Three samples of each scaffold were analyzed, and the weight range was 5 - 10 mg. From -50 °C to 200 °C, two heating cycles and an intermediate cooling cycle were carried out, and the heating and cooling rates were 10 °C / min. In order to compare different samples, only the second heating cycle was considered to determine the melting point.

[0101] (4) Tensile strength: Cut the prepared nanofiber scaffold into experimental samples with a length×width of 10 mm×50 mm, and prepare 3 samples for each group. Measure the thickness of each experimental sample with a micrometer. Use an electronic universal testing machine to measure the tensile strength at a crosshead speed of 20 mm / min under room temperature conditions.

[0102] (5) Elongation at break: Cut the prepared nanofiber scaffold into experimental samples with a length×width of 10 mm×50 mm, and prepare 3 samples for each group. Measure the thickness of each experimental sample with a micrometer. Use an electronic universal testing machine to measure the elongation at break at a crosshead speed of 20 mm / min under room temperature conditions.

[0103] The test results are shown in Table 1.

[0104] Table 1

[0105]

[0106]

[0107] The surface of the double-layer electrospun tube prepared by the present invention has a high porosity, a high hydrophilicity (contact angle above 50°), a melting point reaching 120 - 135 °C, a tensile strength above 4.4 MPa, and an elongation at break above 420%.

[0108] The applicant declares that the present invention uses the above embodiments to illustrate the electrospun double-layer tube and its preparation and application of the present invention, but the present invention is not limited to the above embodiments, that is, it does not mean that the present invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, the equivalent replacement of the raw materials selected by the present invention, the addition of auxiliary components, and the selection of specific methods, etc., all fall within the protection scope and the disclosure scope of the present invention.

Claims

1. An electrospun double-layer tube for reducing tendon adhesion, characterized in that, The electrospun double-layer tube is composed of an inner layer and an outer layer. The inner layer is composed of gelatin methacryloylated derivative and polyvinyl alcohol, and the outer layer is composed of lactide-caprolactone copolymer. Both the inner layer and the outer layer are electrospun membranes prepared by the electrospinning process.

2. The electrospun double-layer tube according to claim 1, wherein The weight-average molecular weight of the polyvinyl alcohol is 50,000 - 150,000 Da; Preferably, the weight-average molecular weight of the lactide-caprolactone copolymer is 50,000 - 200,000 Da; Preferably, the mass ratio of the gelatin methacryloylated derivative to the polyvinyl alcohol in the inner layer is 1:1 - 1:

10.

3. The electrospun double-layer tube according to claim 1 or 2, characterized in that, The thickness of the inner layer is 0.05 - 0.5 mm; Preferably, the thickness of the outer layer is 0.05 - 0.5 mm.

4. The preparation method of the electrospun double-layer tube according to any one of claims 1-3, characterized in that, The preparation method includes the following steps: (1) Using the PEG solution as the electrospinning solution, perform electrospinning to obtain a PEG electrospun membrane layer on the collecting rod; (2) Using the solution containing the gelatin methacryloylated derivative and polyvinyl alcohol as the electrospinning solution, perform electrospinning to obtain the inner layer on the PEG electrospun membrane layer; (3) Using the lactide-caprolactone copolymer solution as the electrospinning solution, perform electrospinning to obtain the outer layer on the inner layer; (4) Use ethanol to detach the obtained electrospun membrane from the collecting rod, and then perform heat setting to obtain the electrospun double-layer tube for reducing tendon adhesion.

5. The preparation method according to claim 4, wherein The PEG solution is obtained by dissolving PEG in chloroform at room temperature; Preferably, the mass percentage concentration of the PEG solution is 20 - 40%.

6. The preparation method according to claim 4, characterized in that, The collecting rod is a stainless steel tube with a diameter of 1 - 10 mm; Preferably, in the electrospinning in step (1), the injection speed of the electrospinning solution is 10 - 40 μl / min, and the applied voltage is 10 - 35 kV; Preferably, in the electrospinning in step (1), the rotational receiving speed of the collecting rod is 500 - 2000 r / h, and the receiving distance is 10 - 40 cm; Preferably, the electrospinning time in step (1) is 5 - 20 min.

7. The preparation method according to claim 4, characterized in that, The solution containing the gelatin methacryloylated derivative and polyvinyl alcohol in step (2) is prepared by dissolving the gelatin methacryloylated derivative and polyvinyl alcohol in ultrapure water; Preferably, the total mass percentage concentration of the gelatin methacryloylated derivative and polyvinyl alcohol in the solution containing the gelatin methacryloylated derivative and polyvinyl alcohol in step (2) is 1 - 10%; Preferably, in the electrospinning in step (2), the injection speed of the electrospinning solution is 10 - 40 μl / min, and the applied voltage is 10 - 35 kV; Preferably, in the electrospinning in step (2), the rotational receiving speed of the collecting rod is 500 - 2000 r / h, and the receiving distance is 10 - 40 cm; Preferably, the electrospinning time in step (2) is 20 - 80 min.

8. The preparation method according to claim 4, characterized in that, The lactide-caprolactone copolymer solution in step (3) is obtained by dissolving the lactide-caprolactone copolymer in a solvent; Preferably, the solvent is selected from any one or at least two combinations of hexafluoroisopropanol, dichloromethane, chloroform or acetone, and hexafluoroisopropanol is further preferred; Preferably, the mass percentage concentration of the lactide-caprolactone copolymer solution in step (3) is 5-25%; Preferably, in the electrospinning of step (3), the injection rate of the electrospinning solution is 10-40 μl / min, and the applied voltage is 10-35 kV; Preferably, in the electrospinning of step (3), the rotational receiving speed of the collecting rod is 500-2000 r / h, and the receiving distance is 10-40 cm; Preferably, the electrospinning time in step (3) is 20-80 min.

9. The preparation method according to claim 4, characterized in that The temperature of the heat setting in step (4) is 25-40 °C, and the time of the heat setting is 30-60 min.

10. Use of the electrospun double-layer tube for reducing tendon adhesion according to any one of claims 1-3 in a tendon repair material.

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