Multifunctional composite artificial blood vessel and preparation method thereof

Abstract

The application discloses a multifunctional composite artificial blood vessel and a preparation method thereof. The artificial blood vessel is a three-layer structure, comprising an inner layer, a middle layer and an outer layer. The inner layer, the middle layer and the outer layer are tightly combined and inseparable. The artificial blood vessel port is a hollow cylindrical structure. The inner layer is a hydrophilic inner layer. The middle layer is composed of a dense layer and a spiral ring support structure. The outer layer is an electrospinning layer. The composite artificial blood vessel comprises three layers: the inner layer is an electrospinning layer with good blood compatibility; the middle layer is a dense layer for providing mechanical properties and providing certain mechanical strength for the artificial blood vessel; and the outer layer is a fiber layer for contacting with tissues. The composite artificial blood vessel has good anti-leakage and anti-bending properties. In addition, compared with a traditional ePTFE blood vessel, the blood vessel has excellent blood compatibility and good flexibility. The method is simple to operate and suitable for commercial scale production. The inner diameter size range can be adjusted.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, specifically to a multifunctional composite artificial blood vessel and its preparation method. Background Technology

[0002] Clinically, autologous blood vessels are generally used for fistula creation. However, in most cases, patients' own blood vessels are in poor condition. When autologous fistulas cannot be used for hemodialysis, expanded polytetrafluoroethylene (ePTFE) artificial blood vessels are usually used, such as Gore and Bard artificial blood vessels. ePTFE is a non-elastic material, and the blood vessel deforms due to stress at the implanted curved areas. For example, GORE-Acuseal (National Medical Device Registration Certificate 20153462072) uses two layers of ePTFE, with a low-permeability silicone layer in the middle. Although its mechanical properties meet the puncture requirements, the material itself has poor cell affinity and is non-degradable. The small gap between the inner and outer layers makes it difficult for endothelial cells to grow into the vessel wall, resulting in the blood vessel not perfectly integrating with human tissue. Furthermore, the circumferential elasticity of the blood vessel is generally poor, and the overall vessel wall is relatively thick, leading to more adverse reactions after implantation. In clinical applications, multi-layered structures are prone to delamination, causing phenomena such as pseudo-arterial dissection. Furthermore, products like the PROPATEN series are designed to achieve flexural strength by intermittently adjusting the density of the ePTFE tube wall. By controlling the expansion rate of different sections, a reinforcing ring structure is created within the material itself. The inner layer is grafted with heparin using CBAS technology for a longer-lasting anticoagulant effect. While this allows for precise control of the tube wall density to achieve excellent anti-kinking properties, the inner wall reinforcing ring area remains a highly dense structure. The degree of endothelialization on its inner surface is uneven and difficult to achieve, posing a high risk of thrombosis once heparin loses its effectiveness. In addition, Boston Scientific products, which involve winding and reheating hot-extruded expanded polytetrafluoroethylene tubes to create a spiral-shaped vascular wall, are prone to developing uneven textures and irregular intima structures, increasing the risk of complications such as thrombosis.

[0003] In existing technologies, multilayer artificial blood vessels are prone to interlayer delamination due to large gaps between layers and poor adhesion, resulting in pseudoaneurysms in clinical practice. The main problem with the smallest diameter vessels remains the endothelialization process. Clinicians recommend an endothelialization period of approximately one month. The dense inner surface of most ePTFE tubes leads to a prolonged endothelialization process, resulting in complications such as intimal thickening and thrombosis. Therefore, it is necessary to develop a composite artificial blood vessel with an inner surface that promotes endothelialization and superior mechanical properties. Summary of the Invention

[0004] The purpose of this invention is to provide a novel multifunctional composite artificial blood vessel that is leak-proof, bend-resistant, anticoagulant, and promotes endothelialization, as well as its preparation method, to solve the above-mentioned technical problems.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] The present invention provides a multifunctional composite artificial blood vessel, which has a three-layer structure, including an inner layer, a middle layer and an outer layer. The inner layer, the middle layer and the outer layer are tightly bonded together and cannot be separated. The port of the artificial blood vessel is a hollow cylindrical structure. The inner layer is a hydrophilic inner layer. The middle layer is composed of a dense layer and a spiral ring support structure. The outer layer is an electrospun layer.

[0007] Furthermore, the inner layer has a thickness of 1μm to 1000μm, the outer layer has a thickness of 1μm to 500μm, and the dense layer has a thickness of 1μm to 1000μm.

[0008] Furthermore, the spiral ring support structure has a spiral ring diameter of 0.1~2mm and a ring spacing of 1~5mm.

[0009] A method for preparing a multifunctional composite artificial blood vessel includes the following steps:

[0010] S1. Dissolve the polymer compound in a solvent to obtain a spinning solution with a w / v of 5~30% and an electrospray solution with a w / v of 1~60% respectively;

[0011] S2. Place the spinning solution on the mandrel device and perform double-sided electrospinning. The spinning consists of two types of fiber filaments stacked together to obtain a porous electrospinned fiber inner layer with pores decreasing from the inside to the outside. Dry appropriately to remove residual solvent.

[0012] S3. Using the inner layer as the receiving surface, a preliminary coating is applied using electro-spray liquid to obtain a dense inner film layer.

[0013] S4. Using the internal dense layer as the contact surface, the motion law of the contact surface is set, and the polymer granules are thermally extruded to obtain a spiral ring support structure, so that the internal dense layer and the spiral ring support structure form an integrated structure.

[0014] S5. Continue intermittent electro-spraying on the surface structure obtained in S4 to obtain an external dense layer;

[0015] S6. Using the outer dense layer as the receiving surface, electrospinning coating is performed using spinning solution. The rotation speed of the receiving shaft is controlled, and the material is dried to obtain a porous, regularly oriented electrospinned fiber outer layer, ultimately resulting in a composite artificial blood vessel.

[0016] Furthermore, the polymeric compound in S1 is selected from one or more of gelatin, silk fibroin, sodium heparin, polycaprolactone, polylactide, polyurethane, and poly(lactide-caprolactone); the solvent is selected from one or more of formic acid, N,N-dimethylformamide, N,N-dimethylacetamide, acetone, tetrahydrofuran, and hexafluoroisopropanol; the molecular weight of the gelatin and silk fibroin is between 10,000 and 300,000, the weight-average molecular weight of the polycaprolactone, polylactide, and polyurethane is between 10,000 and 1,000,000, and the intrinsic viscosity of the polycaprolactone and polylactide is 0.5-2.0 dL / g.

[0017] Furthermore, the weight-average molecular weight of the polycaprolactone is 60,000 to 300,000, the weight-average molecular weight of the polylactide is 50,000 to 500,000, and the weight-average molecular weight of the polyurethane is 60,000 to 500,000.

[0018] Furthermore, the spinning solutions used in steps S2 and S6 have different compositions. In step S2, a blended spinning solution of PU, PCL, and PLA is used, and natural polymer compound additives such as gelatin and heparin are added. In step S6, the outer layer is prepared by spinning a blended spinning solution of PU, PLC, etc.

[0019] Furthermore, the spinning methods used in S2 and S6 are different. In step S2, double-sided conjugate electrospinning is used, which can introduce a variety of bioactive components, improve biocompatibility, facilitate rapid infiltration of cells in vivo, and at the same time use materials with different degradation cycles to achieve gradient degradation and maintain the stability of the inner layer structure. Step S6 can be prepared by ordinary electrospinning.

[0020] Furthermore, the inner layer of the electrospun fiber in S2 contains one or more of gelatin, silk fibroin, and sodium heparin; the pore size of the electrospun fiber gradually decreases from the inside to the outside.

[0021] Furthermore, the electrospinning parameters in S2 and S6 are as follows: the distance between the spinneret and the mandrel receiving device is adjusted to 5~30cm; the spinning ambient temperature is 15~60℃, the ambient humidity is 15~70%RH, the voltage is adjusted to 10~30kV, the solution feeding rate is 0.1~6mL / h, and the roller speed is 50~1000rad / min.

[0022] Furthermore, the electrospinning parameters in S2 are as follows: the distance between the spinneret and the mandrel receiving device is adjusted to 5-20 cm; the ambient temperature for spinning is 15-60℃, the ambient humidity is 15-60%RH, the voltage is adjusted to 10-30 kV, the solution feeding rate is 0.1-5 mL / h, and the roller speed is 50-500 rad / min.

[0023] Furthermore, the electrospinning parameters in S6 are as follows: solution feed rate of 2~6 mL / h, receiving distance of 8~15 cm, roller speed of 500~1000 rad / min, ambient temperature of 25~40℃, ambient humidity of 30~60% RH, and voltage adjustment to 10~20 kV; the fiber diameter in S6 is 50 nm~5000 nm.

[0024] Furthermore, in step S2, the electrospinning time is 1~30h; in step S6, the electrospinning time is 0.5~15h.

[0025] Furthermore, in S2, the electrospinning time is 1-10 hours.

[0026] Furthermore, the parameters of the electro-injection in S3 are as follows: solution feeding rate is 2~5mL / h, receiving distance is 5~10cm, roller speed is 50~200rad / min, ambient temperature is 25~40℃, ambient humidity is 30~60% RH, and voltage is adjusted to 8~15kV.

[0027] Furthermore, the helical ring support structure of S4 uses polymer granules made of one or more of polyurethane, polycaprolactone, polylactide, perfluoroethylene propylene copolymer (FEP), and polytetrafluoroethylene (PTFE).

[0028] Furthermore, the parameters of the S5 electro-injection are as follows: solution feeding rate is 1~4mL / h, receiving distance is 8~12cm, roller speed is 100~500rad / min, ambient temperature is 25~40℃, ambient humidity is 30~60%RH, and voltage is adjusted to 8~15kV.

[0029] Furthermore, in S6, the outer layer of the electrospun fiber has a circumferentially oriented electrospun structure.

[0030] Based on the above technical solution, the embodiments of the present invention can produce at least the following technical effects:

[0031] (1) The multifunctional composite artificial blood vessel provided by this invention has an inner layer of electrospun fiber with good blood compatibility. It adopts a conjugate electrospinning method to composite multiple materials with different degradation cycles. Its electrospun scaffold has a larger pore size, better biocompatibility, and faster cell infiltration speed. The introduction of heparin components into the spinning process can achieve an anticoagulant effect to a certain extent and accelerate the endothelialization process. After some materials degrade, the inner wall can still maintain good stability, preventing the phenomenon of pseudoaneurysm caused by the peeling of multilayer structures.

[0032] (2) The multifunctional composite artificial blood vessel provided by the present invention is composed of a dense layer and a spiral ring support structure in the middle layer. The dense layer not only plays the role of bonding the inner and outer layers, but its relatively dense structure is beneficial to the puncture resistance of the blood vessel and greatly improves the overall leakage resistance. In addition, the spiral support ring embedded in the blood vessel part area is a high-density structure in the middle layer. Due to the multiple reinforcement of the multiple dense layers in the middle layer, it is embedded in it. Compared with the surrounding electro-sprayed structure, its higher hardness and density further improve the radial support force of the blood vessel wall in the bending part and achieve anti-bending and anti-kinking performance.

[0033] (3) The multifunctional composite artificial blood vessel provided by the present invention has an outer layer structure of a regularly oriented electrospun layer. By adjusting the spinning process, the circumferential spinning structure further improves the overall bending resistance of the blood vessel, giving it a smaller kink radius and stronger stability. In addition, the spinning structure helps to improve the compatibility of the blood vessel with the surrounding tissue and accelerates cell infiltration.

[0034] (4) The multifunctional composite artificial blood vessel provided by the present invention can be appropriately cut and applied to different scenarios according to clinical needs. The blood vessel can be used for in vivo vascular transplantation surgery, arteriovenous fistula or coronary artery bypass surgery, etc. For example, in the process of arteriovenous fistula application, the fistula maturation period can be greatly shortened, the puncture resistance is good, and immediate puncture can be achieved. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0036] Figure 1 The image shows the fibrous morphology of the composite artificial blood vessel inner lining fibrous membrane prepared according to the present invention.

[0037] Figure 2 Cross-sectional view of the composite artificial blood vessel prepared according to the present invention (excluding the spiral support ring structure);

[0038] Figure 3 This is a schematic diagram of the cross-section of the composite artificial blood vessel prepared according to the present invention;

[0039] Figure 4 This is a fibrous morphology diagram of the outer fibrous membrane of the artificial blood vessel prepared according to the present invention.

[0040] Figure 5 This is a schematic diagram of an embodiment of the present invention;

[0041] Figure 6 This is a schematic diagram of an embodiment of the present invention;

[0042] Figure 7 This is a schematic diagram of an embodiment of the present invention;

[0043] In the diagram: 1. Inner layer; 2. Middle layer; 3. Outer layer; 4. Spiral ring-shaped support structure. Detailed Implementation

[0044] It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention.

[0045] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0046] Because the ring structure is not conducive to vascular puncture, it is also unsuitable for coronary artery bypass grafting sites. To address this issue, the spiral ring structure can be extruded into a suitable segment of the blood vessel, achieving strong bending resistance in certain sections. By controlling the appropriate segment length, it can meet the length requirements for clinical puncture while also ensuring the blood vessel's resistance to bending and kinking in specific locations.

[0047] In step S5, during the intermittent electro-spraying process, since the solute contained in a single electro-spray is insufficient to form a dense film of a certain thickness, and continuous electro-spraying for a long time is prone to excessive solvent penetration into the interior, causing structural damage, it is necessary to repeat the process intermittently multiple times to achieve complete coverage while allowing the solvent in the electro-spraying solution sufficient time to evaporate.

[0048] Considering the potential damage to the inner fiber membrane during the initial electro-spraying process, the concentration of the electro-spraying solution must be within the acceptable range for the electro-spraying technology. A higher concentration of electro-spraying solution should be used to prevent excessive damage to the inner layer by the solvent. After the surface film has formed, the thermal extrusion spiral ring step and subsequent intermittent electro-spraying are performed. Electro-spraying can be carried out using a lower concentration. Through the secondary dissolution and integration of the solvent with the initial electro-sprayed film, stable adhesion and reinforcement of the spiral ring are achieved.

[0049] Example 1

[0050] A method for preparing a multifunctional composite artificial blood vessel includes the following steps:

[0051] (1) Solution preparation: Dissolve PLCL (intrinsic viscosity of about 1.0~1.5 dL / g) in HFIP and stir overnight to obtain electrospinning solution No. 1 with a concentration of 20% (w / v); Dissolve PCL (intrinsic viscosity of 1.2~1.7 dL / g) and PU (molecular weight of about 60,000~80,000) in HFIP with a weight ratio of PCL:PU = 20:80, heat and stir in a water bath at 40℃ for 12 hours to obtain electrospinning solution No. 2 with a concentration of 10% (w / v). Both solutions are used for conjugated electrospinning; Dissolve PU (molecular weight of 60,000~80,000) in a mixed solvent of N,N-dimethylformamide (DMF) and acetone (volume ratio of 5 / 5), heat and stir in a water bath at 40℃ overnight to obtain solutions with concentrations of 8% and 15% (w / v) for electrospraying.

[0052] (2) Conjugate electrospinning: The two electrospinning solutions obtained in (1) were injected into 10 mL syringes, and 21G stainless steel needles were attached and placed at both ends of the receiving shaft. The distance between the spinneret and the roller was adjusted to 10-15 cm; the ambient temperature for spinning was 25-40℃, the ambient humidity was 30-60%RH, the positive / negative voltage for double-sided spinning was adjusted to ±12-18 kV, the roller speed was 100 rad / min, the solution feeding rate was 2-6 mL / h, and spinning was carried out for 1 h. The obtained fiber membrane was dried for 12 h to remove excess residual solvent and obtain the electrospinned inner layer structure of the composite blood vessel.

[0053] (3) Preliminary electro-spraying: a) Adjust the PU solution concentration to 15% (w / v), the feed rate to 3.0 mL / h, the electro-spraying distance to 5-10 cm, the roller speed to 50 rad / min, the ambient temperature to 40℃, the ambient humidity to 50% RH, and the voltage to 10 kV. Perform electro-spraying for 30 min and then stop for 20 min. This allows a small amount of electro-sprayed liquid to adhere to and fuse with the inner fiber surface, reducing the porosity of the fiber layer. At the same time, the thin PU film formed on the surface helps to isolate the electrospinning inner layer from damage caused by the hot extrusion ring.

[0054] (4) 3D printing hot extrusion: The spiral support ring is prepared by hot extrusion. The raw material is ePTFE (weight average molecular weight of 150,000). The hot extrusion parameters are adjusted as follows: temperature 330℃, host extrusion rate 2Hz. The first layer of dense film obtained in step (3) is used as the receiving surface. The distance between the dense film and the extrusion head of the hot extruder is 8cm. The movement law of the receiving surface of the dense film is: rotation speed 16Hz, moving parallel from left to right at a speed of 2cm / s for 5s, and then forming a spiral ring structure.

[0055] (5) Secondary intermittent electro-spraying: Using the structural surface obtained in step (4) as the receiving surface, the concentration is adjusted to 8% (w / v), the feeding rate is 3.0 mL / h, the roller speed is 50 rad / min, and electro-spraying is performed for 30 min to eliminate porosity and form a thin, dense electro-sprayed film. At the same time, the spiral ring support structure is completely covered and tightly adhered to prevent loosening. Drying is stopped intermittently in between, and then electro-spraying is performed again to achieve the specified thickness. The film is then placed in an oven to dry and form a dense layer of a certain thickness.

[0056] (6) Using the dense middle layer structure obtained in step (5) as the receiving surface, a PU / PCL (8:2) blend solution is used as the spinning solution. The distance between the spinneret and the rotating shaft is adjusted to 12 cm. The spinning environment temperature is 40℃, the ambient humidity is 30~40%RH, the voltage is adjusted to 15kV, the roller speed is 600rad / min, the solution feeding rate is 4mL / h, and spinning is carried out for 2 hours to obtain an oriented electrospun fiber outer layer. The fiber is then vacuum dried overnight to obtain the three-layer multifunctional composite artificial blood vessel of the present invention.

[0057] Example 2

[0058] A method for preparing a multifunctional composite artificial blood vessel includes the following steps:

[0059] (1) Solution preparation: Dissolve PLCL (intrinsic viscosity about 1.0~1.5 dL / g) and gelatin (glue strength 250 g bloom) in HFIP at a ratio of 5:1 and stir overnight to obtain electrospinning solution No. 1 with a concentration of 18% (w / v); Dissolve PLCL (intrinsic viscosity about 1.0~1.5 dL / g) and PU (molecular weight about 60,000~80,000) in HFIP with a mass ratio of PLCL:PU = 20:80 and heat and stir in a water bath at 40℃ for 12 hours to obtain electrospinning solution No. 2 with a concentration of 10% (w / v). Both solutions are used for conjugated electrospinning; Dissolve PU (molecular weight 60,000~80,000) in a mixed solvent of N,N-dimethylformamide (DMF) and acetone (volume ratio of 8 / 2) and heat and stir in a water bath at 40℃ overnight to obtain solutions with concentrations of 5% and 10% (w / v) for electrospraying.

[0060] (2) Conjugate electrospinning: The two electrospinning solutions obtained in (1) were injected into 10 mL syringes, and 21G stainless steel needles were added and placed at both ends of the receiving shaft. The distance between the spinneret and the roller was adjusted to 10~15 cm; the ambient temperature for spinning was 25~40℃, the ambient humidity was 30~40%RH, the positive voltage was adjusted to 12~18 kV, the negative voltage was adjusted to -12~18 kV, the roller speed was 100 rad / min, the solution feeding rate was 2~6 mL / h, and spinning was carried out for 1 h. The obtained fiber membrane was dried for 12 h to remove excess residual solvent and obtain the electrospinned inner layer structure of the composite blood vessel.

[0061] (3) Preliminary electro-spraying: a) Adjust the PU solution concentration to 10% (w / v), the feed rate to 3.0 mL / h, the electro-spraying distance to 8~12 cm, the roller speed to 50 rad / min, the ambient temperature to 40℃, the ambient humidity to 50% RH, and the voltage to 10 kV. Perform electro-spraying for 30 min and then stop for 20 min. This allows a small amount of electro-sprayed liquid to adhere to and fuse with the inner fiber surface, reducing the porosity of the fiber layer. At the same time, the dense PU film formed on the surface helps to isolate the thermal extrusion ring from the thermal damage to the electrospinning inner layer.

[0062] (4) 3D printing hot extrusion: The spiral support ring is prepared by hot extrusion. The raw material is PU (weight average molecular weight of 200,000). The hot extrusion parameters are adjusted as follows: temperature 200℃, host extrusion rate 2Hz. The internal dense film obtained in step (3) is used as the receiving surface. The distance between the dense film and the extrusion head of the hot extruder is 8cm. The movement law of the receiving surface of the dense film is: rotation speed 16Hz, moving parallel from left to right at a speed of 1.5cm / s for 3s, and then forming a partial spiral ring structure.

[0063] (5) Secondary electro-spraying: Using the structural surface obtained in step (4) as the receiving surface, the concentration is adjusted to 5% (w / v), the feeding rate is 4.0 mL / h, the roller speed is 50 rad / min, and electro-spraying is performed for 30 minutes to eliminate porosity and form a thin, dense electro-sprayed film. At the same time, the spiral ring support structure is completely covered and tightly adhered to prevent loosening. The film is then placed in an oven to dry and form a dense layer of a certain thickness.

[0064] (6) Using the dense middle layer structure obtained in (5) as the receiving surface, a PU / PLCL (8:2) blend solution was used as the spinning solution. The distance between the spinneret and the rotating shaft was adjusted to 12 cm. The spinning environment temperature was 40℃, the ambient humidity was 30~40%RH, the voltage was adjusted to 15kV, the roller speed was 600rad / min, the solution feeding rate was 4mL / h, and spinning was carried out for 2h to obtain an oriented electrospun fiber outer layer. The fiber was then vacuum dried overnight to obtain the three-layer composite artificial blood vessel of the present invention.

[0065] Example 3

[0066] A method for preparing a multifunctional composite artificial blood vessel includes the following steps:

[0067] (1) Solution preparation: PCL (intrinsic viscosity approximately 0.8~1.2 dL / g) and gelatin (glue strength 250 g bloom) were dissolved in HFIP at a ratio of 3:1 to obtain a 20% (w / v) solution. Sodium heparin (>150 U / mg) was dissolved in formic acid solution at a concentration of 200 mg / ml. The mixture was stirred overnight until homogeneous. The PCL / gelatin solution and the sodium heparin solution were thoroughly mixed at a volume ratio of 8:2 to obtain electrospinning solution ①. PCL (intrinsic viscosity approximately 0.8~1.2 dL / g) and PU (molecular weight approximately 100,000~150,000) were dissolved in HFIP at a mass ratio of PCL:PU = 20:80. The mixture was heated and stirred in a water bath at 40℃ for 12 hours to obtain electrospinning solution ② with a concentration of 10% (w / v). Both solutions were used for conjugated electrospinning. PU (molecular weight 100,000~150,000) was dissolved in N In a mixed solvent of N-dimethylformamide (DMF) and acetone (volume ratio 8 / 2), the mixture was heated in a water bath at 40°C overnight with stirring to obtain solutions with concentrations of 3%, 8%, and 15% (w / v), which were then used for electro-injection.

[0068] (2) Conjugate electrospinning: The two electrospinning solutions obtained in (1) were injected into 10 mL syringes, and 21G stainless steel needles were added and placed at both ends of the receiving shaft. The distance between the spinneret and the roller was adjusted to 10~15 cm; the ambient temperature for spinning was 25~40℃, the ambient humidity was 30~40%RH, the positive voltage was adjusted to 12~18 kV, the negative voltage was adjusted to -12~18 kV, the roller speed was 100 rad / min, the solution feeding rate was 2~6 mL / h, and spinning was carried out for 1 h. The obtained fiber membrane was dried for 12 h to remove excess residual solvent and obtain the electrospinned inner layer structure of the composite blood vessel.

[0069] (3) Preliminary electro-spraying: a) Adjust the PU solution concentration to 15% (w / v), the feed rate to 2.0 mL / h, the electro-spraying distance to 5-10 cm, the roller speed to 50 rad / min, the ambient temperature to 40℃, the ambient humidity to 50% RH, and the voltage to 8-10 kV. Perform electro-spraying for 20 min and then stop for 20 min. This allows a small amount of electro-sprayed liquid to adhere to and fuse with the inner fiber surface, reducing the porosity of the fiber layer. At the same time, the dense PU film formed on the surface helps to isolate the thermal extrusion ring from the thermal damage to the electrospinning inner layer.

[0070] (4) 3D printing hot extrusion: The spiral support ring is prepared by hot extrusion. The raw material is PLA (intrinsic viscosity 3.2 dL / g). The hot extrusion parameters are adjusted as follows: temperature 180℃, host extrusion rate 4Hz. The internal dense film obtained in step (3) is used as the receiving surface. The distance between the dense film and the extrusion head of the hot extruder is 8cm. The movement law of the receiving surface of the dense film is: rotation speed 16Hz, moving parallel from left to right at a speed of 3cm / s for 10s, and then forming a spiral ring structure.

[0071] (5) Secondary electro-spraying: Using the structural surface obtained in step (4) as the receiving surface, the concentration is adjusted to 8% and 5% (w / v), the feeding rate is 4.0 mL / h, the roller speed is 50 rad / min, and electro-spraying is performed for 30 minutes to eliminate porosity and form a thin, dense electro-sprayed film. At the same time, intermittent spraying is used, with the solvent evaporating in between before the next spraying, so that the spiral ring support structure is completely covered and tightly adhered to prevent loosening. Place it in an oven to dry and form a dense layer of a certain thickness.

[0072] (6) Using the dense middle layer structure obtained in (5) as the receiving surface, a PU / PCL (8:2) blend solution is used as the spinning solution. The distance between the spinneret and the rotating shaft is adjusted to 12 cm. The spinning environment temperature is 40℃, the ambient humidity is 30~40%RH, the voltage is adjusted to 15kV, the roller speed is 800rad / min, the solution feeding rate is 4mL / h, and spinning is carried out for 1h to obtain an oriented electrospun fiber outer layer. The fiber is then vacuum dried overnight to obtain the three-layer composite artificial blood vessel of the present invention.

[0073] The vascular grafts prepared in Examples 1-3 of this invention were used in in vivo vascular transplantation surgery. After implantation, they were basically stable and no complications such as thrombosis and interlaminar dissection occurred. The blood vessels could exist stably in vivo without adverse reactions. Long-term efficacy verification is underway.

[0074] Finally, it should be noted that:

[0075] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a multifunctional composite artificial blood vessel, characterized in that, Includes the following steps: S1. Dissolve the polymer compound in a solvent to obtain a spinning solution with a w / v of 5~30% and an electrospray solution with a w / v of 1~60% respectively; S2. Place the spinning solution on the mandrel device and perform double-sided electrospinning. The spinning consists of two types of fiber filaments stacked together to obtain a porous conjugated electrospinned fiber inner layer with pores decreasing from the inside to the outside. Dry and remove residual solvent. S3. Using the inner layer as the receiving surface, a preliminary coating is applied using electro-spray liquid to obtain a dense inner film layer. S4. Using the internal dense film layer as the contact surface, the motion law of the contact surface is set, and the polymer granules are thermally extruded to obtain a spiral ring support structure, so that the internal dense film layer and the spiral ring support structure form an integrated structure. S5. Continue electro-spraying on the surface structure obtained in S4 to obtain an outer dense layer; S6. Using the outer dense layer as the receiving surface, electrospinning coating is performed using spinning solution. The rotation speed of the receiving shaft is controlled, and the material is dried to obtain a porous, regularly oriented electrospinned fiber outer layer, ultimately resulting in a composite artificial blood vessel.

2. The method for preparing a multifunctional composite artificial blood vessel according to claim 1, characterized in that, The high molecular weight compound in S1 is selected from one or more of gelatin, silk fibroin, sodium heparin, polycaprolactone, polylactide, polyurethane, and poly(lactide-caprolactone); the solvent is selected from one or more of formic acid, N,N-dimethylformamide, N,N-dimethylacetamide, acetone, tetrahydrofuran, and hexafluoroisopropanol; the molecular weight of the gelatin and silk fibroin is between 10,000 and 300,000, the weight-average molecular weight of the polycaprolactone, polylactide, and polyurethane is between 10,000 and 1,000,000, and the intrinsic viscosity of the polycaprolactone and polylactide is 0.5-2.0 dL / g.

3. The method for preparing a multifunctional composite artificial blood vessel according to claim 1, characterized in that, The parameters for electrospinning in steps S2 and S6 are as follows: the distance between the spinneret and the mandrel receiving device is adjusted to 5-30 cm; the ambient temperature for spinning is 15-60℃, the ambient humidity is 15-70%RH, the voltage is adjusted to 10-30 kV, the solution feeding rate is 0.1-6 mL / h, and the roller speed is 50-1000 rad / min. In step S2, the electrospinning time is 1-30 h; in step S6, the electrospinning time is 0.5-15 h.

4. The method for preparing a multifunctional composite artificial blood vessel according to claim 1, characterized in that, The spinning solutions used in steps S2 and S6 have different compositions. In step S2, a blended spinning solution of PU, PCL and PLA is used for double-sided conjugated electrospinning. In addition, natural polymer compound auxiliaries such as gelatin and heparin are added to the blended spinning solution to enhance hydrophilicity and short-term anticoagulation. In step S6, a blended spinning solution of PU and PCL is used to prepare the outer layer by single-sided spinning.

5. The method for preparing a multifunctional composite artificial blood vessel according to claim 1, characterized in that, The parameters for the initial spraying in S3 are as follows: solution feeding rate is 2~5mL / h, receiving distance is 5~10cm, roller speed is 50~200rad / min, ambient temperature is 25~40℃, ambient humidity is 30~60%RH, and voltage is adjusted to 8~15kV.

6. The method for preparing a multifunctional composite artificial blood vessel according to claim 1, characterized in that, The spiral ring support structure of S4 uses polymer granules selected from one or more of polyurethane, polycaprolactone, polylactide, perfluoroethylene propylene copolymer (FEP), and polytetrafluoroethylene (PTFE).

7. The method for preparing a multifunctional composite artificial blood vessel according to claim 1, characterized in that, The parameters of the S5 electro-injection are as follows: solution feeding rate is 1~4mL / h, receiving distance is 8~12cm, roller speed is 100~500 rad / min, ambient temperature is 25~40℃, ambient humidity is 30~60%RH, and voltage is adjusted to 8~15kV.

8. The method for preparing a multifunctional composite artificial blood vessel according to claim 1, characterized in that, The artificial blood vessel has a three-layer structure, including an inner layer (1), a middle layer (2) and an outer layer (3). The inner layer (1), the middle layer (2) and the outer layer (3) are tightly connected and cannot be separated. The port of the artificial blood vessel is a hollow cylindrical structure. The inner layer (1) is a hydrophilic inner layer. The middle layer (2) is composed of a dense layer and a spiral ring support structure (4). The outer layer (3) is an electrospun layer.

9. The method for preparing a multifunctional composite artificial blood vessel according to claim 8, characterized in that, The inner layer (1) has a thickness of 1μm to 1000μm, the outer layer (3) has a thickness of 1μm to 500μm, and the dense layer has a thickness of 1μm to 1000μm.

10. The method for preparing a multifunctional composite artificial blood vessel according to claim 8, characterized in that, The spiral ring support structure (4) has a spiral ring diameter of 0.1~2mm and a ring spacing of 1~5mm.

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