Method for preparing double-layer structure uniform thickness artificial blood vessel

Abstract

The application provides a preparation method of a double-layer structure uniform-wall-thickness artificial blood vessel. A polymer solution layer is first formed outside a blood vessel mold through a leaching method. In a high humidity environment, the mold surface excess solution is removed by means of a centrifugal force, and a uniform wall thickness is formed. Under the rotating condition, an electrostatic spinning method is adopted to uniformly form a fiber outer layer on the inner surface of the artificial blood vessel. The fibers in the fiber outer layer are irregularly arranged. The thickness of the fiber outer layer and the fiber size are controlled by adjusting the parameters of the spinning process. Finally, the artificial blood vessel with good elasticity, uniform wall thickness, and favorable blood flow and cell proliferation is obtained.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of non-woven biomaterials, and particularly relates to a preparation method of a double-layer structure uniform-wall-thickness artificial blood vessel. BACKGROUND

[0002] Artificial blood vessels used for clinical applications are mostly made of hard materials. Since the elasticity and flexibility of hard materials are poor, it is difficult to ensure smooth blood flow in the blood vessel. Therefore, polyurethane materials with good elasticity are selected to make artificial blood vessels. However, since polyurethane itself has good fluidity, the formed artificial blood vessels are prone to uneven wall thickness. In addition, the artificial blood vessels made by compounding with other materials have the problems of poor combination between the inner and outer layers and easy delamination, which affect the performance of the artificial blood vessels.

[0003] In the prior art, a patent document with the application number CN202111404414.7 and the publication date of March 11, 2022 and the name of "a coating method of a woven artificial blood vessel and the artificial blood vessel" adopts a distributed coating method, first completes the oil removal treatment on the woven blank tube, then performs coating on the oil-removed woven blank tube, performs texture processing on the coated woven blank tube, performs coating on the artificial blood vessel after the texture processing, and finally obtains the artificial blood vessel after the coating treatment. The above technical solution can obtain an artificial blood vessel with a uniform inner wall, but the artificial blood vessel obtained by the process has a single membrane structure, is not conducive to cell proliferation, and is not suitable for clinical application.

[0004] Secondly, a patent document with the application number CN202010044393.1 and the publication date of January 12, 2021 and the name of "a preparation method of a puncture-resistant artificial blood vessel material and an artificial blood vessel made therefrom" forms a porous electrospun layer on a mandrel device by using an electrospinning method, and forms a uniform outer layer on the outside of the electrospun layer by using an electrospinning method, thereby obtaining a puncture-resistant artificial blood vessel. However, since the inner wall of the blood vessel in the above technical solution is not uniform, when the blood flows through, it is easy to block the cells or particulate matters in the blood, causing them to settle, which can cause thrombosis over a long period of time, endangering the life of the user. In addition, the method in the above solution is not easy to implement, because the fibers in the inner layer are easily dissolved in the polyurethane solution, and it is difficult to obtain qualified products.

[0005] Therefore, it is necessary to design an improved preparation method of a double-layer structure uniform-wall-thickness artificial blood vessel to solve the above problems. SUMMARY

[0006] The present application relates to the technical field of non-woven biomaterials, and particularly relates to a preparation method of a double-layer structure uniform-wall-thickness artificial blood vessel.

[0007] To achieve the above-mentioned purpose of the application, the present application provides a preparation method of a double-layer structure uniform-wall-thickness artificial blood vessel, comprising the following steps:

[0008] S1, the blood vessel mold is vertically immersed in the prepared polyurethane solution at a temperature of 20-40℃ and a humidity of 80-100%, and then taken out, and after standing for 1-5 min, the blood vessel mold is inverted and inverted for 0.5-1 min; then, the blood vessel mold is rotated around its mold center axis to form a uniform-thickness inner layer of artificial blood vessel on the outer wall of the blood vessel mold, the wall thickness of the inner layer of artificial blood vessel is 100-500 μm, the tube wall micropore size is 0.02-10 μm, and the micropore is a connected pore structure;

[0009] S2, the blood vessel mold with the inner layer of artificial blood vessel formed in step S1 is installed in an electrospinning device, and electrospinning is performed on the outer layer of the rotating inner layer of artificial blood vessel to form a uniform fiber outer layer, thereby obtaining the double-layer structure uniform-thickness artificial blood vessel; wherein the diameter of the fiber in the fiber outer layer is 0.1-10 μm.

[0010] Preferably, in step S2, the thickness of the fiber outer layer is 100-500 μm.

[0011] Preferably, in steps S1 and S2, the rotation speed is 20-100 r / min.

[0012] Preferably, in step S2, the electrospinning conditions are a temperature of 20-40℃ and a humidity of 30-50%.

[0013] Preferably, in step S2, the electrospinning is performed as follows: the polyurethane solution is sprayed out of the spinning nozzle at a speed of 0.1-10 ml / h, enters the high-voltage electric field area with a spinning voltage of 10-25 Kv and a receiving distance of 50-300 mm, and the formed fibers are collected on the rotating blood vessel mold with the inner layer of artificial blood vessel on the surface.

[0014] Preferably, the mass percentage of the polyurethane solution is 10-15%; preferably, the polyurethane is a polyether type or a polyester type polyurethane.

[0015] Preferably, the polyurethane solution is prepared as follows: the polyurethane is dissolved in a solvent, stirred at a speed of 100-600 r / min at a temperature of 10-50℃ for 2-6 h, and then formed after standing for 2-5 h.

[0016] Preferably, in step S1, the speed of inverting the blood vessel mold is 5-20° / min.

[0017] Preferably, in step S1, the diameter of the blood vessel mold is 2-40mm, and the length is 10-50cm; preferably, the material of the blood vessel mold is metal, polyester, ceramic or polytetrafluoroethylene.

[0018] Preferably, the solvent is N, N-dimethylacetamide or N, N-dimethylformamide.

[0019] Preferably, the interval time between step S2 and step S1 is 5-20min, which ensures the formation of the inner layer of micropores.

[0020] The beneficial effects of the present application are:

[0021] 1. The preparation method of the double-layer structure blood vessel with uniform wall thickness provided by the present application, by forming a uniform inner layer of the artificial blood vessel outside the blood vessel mold first, then making the blood vessel mold under the condition of rotation, and uniformly forming a fiber outer layer on the surface of the inner layer of the artificial blood vessel by electrospinning, and the fibers in the fiber outer layer are irregularly arranged, and by adjusting the parameters of the spinning process, the thickness of the fiber outer layer and the fiber size are controlled, and finally a good elastic artificial blood vessel with uniform wall thickness and beneficial to blood flow and cell proliferation is obtained; the above method of preparing the inner and outer layers of the artificial blood vessel by using the same concentration of polyurethane solution, effectively improves the interface compatibility between the inner and outer layers of the artificial blood vessel, at the same time, the interface force between the blood vessel mold and the inner layer of the artificial blood vessel is used to form a uniform and smooth inner wall of the blood vessel, which is beneficial to the blood flow, the specific surface area of the blood vessel is improved by the fibers attached to the outside of the inner layer, which provides the attachment point for the growth of cells, which is beneficial to the adhesion and proliferation of cells, and is beneficial to the fusion between the artificial blood vessel and the human blood vessel.

[0022] 2. The preparation method of the double-layer structure blood vessel with uniform wall thickness provided by the present application, by using the method of first immersing the blood vessel mold into the polyurethane solution, then inverting, and forming a uniform layer of polyurethane solution outside the blood vessel mold under the action of centrifugal force to form the inner layer of the blood vessel, and then forming a fiber outer layer outside the inner layer by electrospinning when the inner layer is in a semi-solid state, which ingeniously combines the physical preparation method and the electrospinning process together, and uses the same raw material to obtain the artificial blood vessel with significant differences between the inner and outer layers, which improves the biocompatibility of the artificial blood vessel and the adhesion between the two layers; by the above method, a good elastic artificial blood vessel with uniform wall thickness and beneficial to blood flow and cell proliferation is obtained, and a preparation method of the double-layer structure blood vessel with uniform wall thickness is provided, which has wide raw material sources, simple preparation, good biocompatibility and is suitable for industrial production. BRIEF DESCRIPTION OF DRAWINGS

[0023] Fig. 1 The structure of the double-layer structure blood vessel with uniform wall thickness provided by the present application is shown in the figure;

[0024] Fig. 2 The preparation method of the double-layer structure wall thickness uniform artificial blood vessel is shown in the figure. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be described in detail below with reference to the drawings and specific embodiments.

[0026] It should be noted here that, in order to avoid obscuring the present application due to unnecessary details, only the structures and / or processing steps closely related to the scheme of the present application are shown in the drawings, and other details not closely related to the present application are omitted.

[0027] In addition, it should be noted that the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or equipment.

[0028] Referring to Figs. 1-2 The present application provides a preparation method of a double-layer structure wall thickness uniform artificial blood vessel, which comprises the following steps:

[0029] S1, preparation of the inner layer of the artificial blood vessel: a cylindrical blood vessel mold is vertically immersed in a pre-prepared polyurethane solution at a temperature of 20-40℃ and a humidity of 80-100%, and then taken out, and after standing for 1-5min, the blood vessel mold is inverted, and inverted for 0.5-1min, so that the polyurethane solution spreads to the outer wall of the entire blood vessel mold; then, the blood vessel mold is rotated around its central axis, and the solution layer on the surface of the blood vessel mold is dispersed under the action of centrifugal force, and an inner layer of the artificial blood vessel with uniform wall thickness is formed on the outer wall of the blood vessel mold;

[0030] S2, preparation of the outer layer of the artificial blood vessel: the blood vessel mold with the artificial blood vessel inner layer formed on its surface in step S1 is installed in an electrospinning device as a receiving device, and a uniform fiber outer layer is formed on the artificial blood vessel inner layer of the rotating blood vessel mold by electrospinning using a pre-prepared polyurethane solution in an environment with a temperature of 20-40℃ and a humidity of 30-50%, thereby obtaining a double-layer structure wall thickness uniform artificial blood vessel.

[0031] Preferably, the polyurethane solution is prepared by dissolving polyurethane in a solvent, stirring at a speed of 100-600 r / min at 10-50 °C for 2-6 h, and standing for 2-5 h to form a polyurethane solution with a mass percentage of 10-15%. When the concentration of the polyurethane solution is within this range, the formed artificial blood vessel has good shaping and excellent strength; when the concentration is less than 10%, the concentration of polyurethane in the artificial blood vessel is too low, and the strength of the blood vessel is not enough; when the concentration is higher than 15%, the viscosity of the polyurethane solution is too large, which is not conducive to spinning; the polyurethane is polyether or polyester polyurethane, and the solvent is N, N-dimethylacetamide or N, N-dimethylformamide.

[0032] Preferably, in step S1, the material of the blood vessel mold is metal, polyester, ceramic or polytetrafluoroethylene, the diameter is 2-40 mm, and the length is 10-50 cm. The blood vessel mold with the size within this range can be used to prepare an artificial blood vessel with good compliance in the human body.

[0033] Preferably, in step S1, the blood vessel mold is inverted at a speed of 5-20 ° / min.

[0034] Preferably, in step S1, the wall thickness of the inner layer of the artificial blood vessel is 100-500 μm. The artificial blood vessel with the wall thickness meeting this condition has good elasticity and good impermeability.

[0035] Preferably, in step S2, electrospinning is performed as follows: the polyurethane solution is sprayed out of a spinning nozzle at a speed of 0.1-10 ml / h, enters a high-voltage electric field region with a spinning voltage of 10-25 Kv and a receiving distance of 50-300 mm, and the formed fibers are collected on the surface of a rotating blood vessel mold to obtain an outer layer of the artificial blood vessel.

[0036] Preferably, the interval between step S2 and step S1 is 5-20 min, which ensures the formation of the micropores in the inner layer.

[0037] Preferably, in step S2, the rotation speed is 20-100 r / min. The rotation speed meeting this condition can ensure that the wall thickness of the artificial blood vessel is uniform. If the rotation speed is greater than 100 r / min, the centrifugal force generated is too large, which increases the amount of polyurethane solution thrown out and causes uneven electrospinning, resulting in uneven wall thickness of the inner layer of the artificial blood vessel membrane and the outer layer of the fiber membrane. If the rotation speed is less than 20 r / min, the centrifugal force generated is too small, the excess solution on the surface of the mold cannot be thrown out, and uneven electrospinning is caused, resulting in uneven wall thickness of the inner and outer layers of the blood vessel.

[0038] Preferably, in step S2, the fiber diameter of the outer layer of fibers is 0.1-10 μm, fibers meeting this condition can form an outer layer of fibers with good film-forming property and large specific surface area outside the inner layer of the artificial blood vessel, fiber diameter that is too small increases the difficulty of spinning; if the fiber diameter is too large, it is easy to form large protrusions on the inner layer of the artificial blood vessel, and the specific surface area of the outer layer of the artificial blood vessel is limited, which is not conducive to cell adhesion and proliferation.

[0039] Preferably, in step S2, the thickness of the outer layer of fibers is 100-500 μm, and the artificial blood vessel prepared under this condition has good performance, when the thickness of the outer layer of fibers is less than 100 μm, the prepared artificial blood vessel has poor anti-leakage ability and is prone to bleeding; and when the thickness is greater than 500 μm, the elasticity of the blood vessel is poor, which is not conducive to the conversion of kinetic energy and potential energy in the blood vessel, and is not conducive to blood flow.

[0040] The preparation method of the double-layer structure artificial blood vessel with uniform wall thickness according to the present application will be further described below in combination with specific examples:

[0041] Example 1

[0042] In this embodiment, a double-layer structure artificial blood vessel with uniform wall thickness is prepared, and the specific preparation method comprises the following steps:

[0043] S1, preparation of the inner layer of the artificial blood vessel: immerse the cylindrical blood vessel mold vertically in the pre-prepared polyurethane solution with a mass percentage of 12% at a temperature of 30°C and a humidity of 95%, then take it out, stand for 2 min, and then invert the blood vessel mold at a speed of 15° / min, invert for 0.6 min, and the polyurethane solution spreads to the outer wall of the entire blood vessel mold; then, rotate the blood vessel mold around its central axis at a speed of 100 r / min, and the solution layer on the surface of the blood vessel mold is dispersed under the action of centrifugal force, forming an inner layer of the artificial blood vessel with a wall thickness of 150 μm on the outer wall of the blood vessel mold; wherein the polyurethane solution is prepared by dissolving polyurethane in a solvent, stirring at a speed of 300 r / min for 4 h at 30°C, and then standing for 5 h; the material of the blood vessel mold is polytetrafluoroethylene, the diameter is 6 mm, and the length is 50 cm;

[0044] S2, preparation of the outer layer of the artificial blood vessel: after step S1 is completed, standing for 15 min, then the blood vessel mold in which the inner layer of the artificial blood vessel is formed in step S1 is installed in the electrostatic spinning device as a receiving device, electrostatic spinning is carried out by using the prepared polyurethane solution in an environment with a temperature of 30 DEG C and a humidity of 30%, a fiber outer layer with a thickness of 300 mu m is formed on the inner layer of the artificial blood vessel of the rotating blood vessel mold, and the diameter of the fiber in the fiber outer layer is 0.1-1 mu m; wherein, the electrostatic spinning is carried out in the following manner: the polyurethane solution is sprayed out from the spinning nozzle at a speed of 3 ml / h, enters the high-voltage electric field area with a spinning voltage of 15 Kv and a receiving distance of 150 mm, and the formed fiber is collected on the surface of the rotating mold to obtain the outer layer of the artificial blood vessel.

[0045] The preparation mechanism of the double-layer structure artificial blood vessel with uniform wall thickness provided by the application is as follows: first, the blood vessel mold is immersed in a polyurethane solution with a specific concentration (10-15%) under suitable temperature and humidity conditions, then the blood vessel mold is taken out and inverted, and the rotation of the blood vessel mold provides centrifugal force for the solution on the surface of the blood vessel mold, so that the solution is uniformly distributed on the outer wall of the blood vessel mold to form a solution layer, the solution layer is rapidly solidified into a film under the preset temperature (20-40 DEG C) and humidity (60-95%), and the film has few pores on the side close to the blood vessel mold and uniform structure, while the side away from the blood vessel mold has pores, which is beneficial to the subsequent preparation of the fiber outer layer and provides attachment points for cell adhesion; at the same time, in the process of rotation, the polyurethane solution with the aforementioned concentration is used as the spinning solution to form a uniform fiber outer layer on the outer wall of the inner layer of the artificial blood vessel by electrostatic spinning, and the concentration of the polyurethane solution, the rotation speed of the mold, the speed of the spinning nozzle, the humidity, the temperature and the voltage of the spinning and other conditions are controlled in the process of spinning to ensure that the fiber with a size (diameter 0.1-10 mu m) matching the inner layer of the artificial blood vessel is formed, and finally a fiber outer layer with a thickness of 100-500 mu m is formed on the inner layer of the artificial blood vessel, and since the inner and outer layers of the artificial blood vessel are selected from the same raw material, the interface compatibility between the inner and outer layers is good, which reflects the excellent biocompatibility of the artificial blood vessel.

[0046] In summary, the preparation method of the double-layer structure artificial blood vessel with uniform wall thickness provided by the application forms a uniform artificial blood vessel inner layer on the outer wall of the blood vessel mold first, then the blood vessel mold is rotated, a uniform fiber outer layer is formed on the surface of the artificial blood vessel inner layer by electrostatic spinning, the thickness and fiber size of the fiber outer layer are controlled by adjusting the parameters in the process of spinning, and finally the artificial blood vessel with good elasticity, uniform wall thickness and favorable blood flow and cell proliferation is prepared.

[0047] The above examples are only used to illustrate the technical solutions of the present application but not limit the present application. Although the present application is described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or equivalent replaced without departing from the spirit and scope of the technical solutions of the present application.

Claims

1. A method for preparing a double-layered structure uniform wall thickness artificial blood vessel, characterized by, Comprising the following steps: S1, in an environment with temperature of 20-40℃ and humidity of 80-100%, the blood vessel mold is vertically immersed in the prepared polyurethane solution, and then taken out, after standing for 1-5min, the blood vessel mold is inverted, and inverted for 0.5-1min; then, the blood vessel mold is rotated around its mold center axis, forming a uniform wall thickness of the artificial blood vessel inner layer on the outer wall of the blood vessel mold, the wall thickness of the artificial blood vessel inner layer is 100-500μm, the tube wall micropore size is 0.02-10μm, and the micropore is a connected pore structure; the mass percentage of the polyurethane solution is 10-15%; the configuration mode of the polyurethane solution is as follows: the polyurethane is dissolved in a solvent, stirred at a speed of 100-600r / min in an environment of 10-50℃ for 2-6h, and after standing for 2-5h, a solution is formed; S2, the blood vessel mold with the artificial blood vessel inner layer formed in step S1 is installed in an electrospinning device, and electrospinning is performed using the polyurethane solution to form a uniform fiber outer layer on the outside of the rotating artificial blood vessel inner layer blood vessel mold, thereby obtaining the double-layer structure uniform wall thickness artificial blood vessel; wherein the diameter of the fiber in the fiber outer layer is 0.1-10μm; the interval time between step S2 and step S1 is 5-20min, ensuring the formation of the inner layer micropore.

2. The method of claim 1, wherein the bi-layered structure is a uniform wall thickness artificial blood vessel. In step S2, the thickness of the fiber outer layer is 100-500μm.

3. The method of claim 1, wherein the bi-layered structure is a uniform wall thickness artificial blood vessel. In steps S1 and S2, the rotation speed is 20-100r / min.

4. The method of claim 1, wherein the bi-layered structure is a uniform wall thickness artificial blood vessel. In step S2, the electrospinning conditions are temperature 20-40℃ and humidity 30-50%.

5. The method of claim 1, wherein the bi-layered structure is a uniform wall thickness artificial blood vessel. In step S2, the electrospinning is performed as follows: the polyurethane solution is sprayed out of the spinning nozzle at a speed of 0.1-10mL / h, enters the high-voltage electric field area with a spinning voltage of 10-25kV and a receiving distance of 50-300mm, and the formed fibers are collected on the rotating blood vessel mold with the artificial blood vessel inner layer on the surface.

6. The method of claim 1, wherein the bi-layered structure is a uniform wall thickness artificial blood vessel. The polyurethane is polyether type or polyester type polyurethane.

7. The method of claim 6, wherein the bi-layered structure is a uniform wall thickness vascular graft. The solvent is N,N-dimethylacetamide or N,N-dimethylformamide.

8. The method of claim 1, wherein the bi-layered structure is a uniform wall thickness vascular graft. In step S1, the speed of inverting the blood vessel mold is 5-20° / min.

9. The method of claim 1, wherein the bi-layered structure is a uniform wall thickness artificial blood vessel. In step S1, the diameter of the blood vessel mold is 2-40mm, and the length is 10-50cm.

10. The method of claim 1, wherein the bi-layered structure is a uniform wall thickness vascular graft. The material of the blood vessel mold is metal, polyester, ceramic or polytetrafluoroethylene.

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