Integrated bionic double-layer anti-bending artificial blood vessel and preparation method thereof

Abstract

The invention relates to an integrated bionic double-layer anti-bending artificial blood vessel and a preparation method thereof.The artificial blood vessel is of a hollow tubular fabric structure and is composed of an inner layer and an outer layer, and the inner surface of the inner layer is a smooth curved surface formed by interweaving multifilaments; the outer layer is of a fluffy, porous and circumferentially oriented arrangement structure formed by hooking, stretching and deforming monofilaments in the multifilaments on the outer surface of the inner layer, and the inner layer and the outer layer are of a tightly connected integrated structure; during preparation, multifilaments are adopted to form the tubular skeleton of the artificial blood vessel through a weaving, knitting or weaving method, napping, snagging or pile cutting is firstly carried out after treatment, then a carding process is carried out, and finally post-treatment shaping is carried out, so that a product is obtained. The preparation method is simple, and the double-layer artificial blood vessel is integrally formed and has good bending resistance; the inner layer and the outer layer of the artificial blood vessel are of an integrated structure, multi-layer structure regeneration of the blood vessel is promoted through the design of the double-layer structure artificial blood vessel, the problem of joint surface layering does not exist during degradation, and a stable structure for cell adhesion growth in the blood vessel regeneration process is provided.

Description

Technical Field

[0001] The invention belongs to the technical field of artificial blood vessels and relates to an integrated bionic double-layer anti-bending artificial blood vessel and a preparation method thereof. Background Art

[0002] With the increase of human life expectancy and chronic diseases, cardiovascular and cerebrovascular diseases have gradually become one of the major health challenges worldwide. As an important medical device, artificial blood vessels play a key role in the treatment of these vascular diseases. Tissue engineering artificial blood vessels are a hot topic in artificial blood vessel research due to their regenerative ability.

[0003] Natural blood vessels have a multi-layer structure, consisting of multiple layers of tissue structures such as the outer membrane, the middle membrane, and the inner membrane. Therefore, when designing tissue engineering vascular scaffolds, the multi-layer structure of blood vessels should be considered. The research on multi-layer artificial blood vessels aims to improve the biocompatibility, mechanical properties and vascular regeneration ability of artificial blood vessels, so as to better meet the clinical needs of vascular replacement and repair. However, the design of existing multi-layer artificial blood vessels has problems such as mismatching the natural blood vessel structure, stratification during degradation, and substandard mechanical properties.

[0004] At present, the preparation method of double-layer artificial blood vessels is mainly based on electrospinning, as well as some other processes combined with electrospinning, such as thermally induced phase separation, micro-imprinting technology, etc. Among them, the construction methods of the double-layer structure include the following four: (1) Patent CN202010012857.0 uses micro / nanofibers of different thicknesses in the inner and outer layers; (2) Patent CN202010012857.0 uses a composite fiber co-spinning and re-dissolving method to prepare a macroporous structure in the outer layer; (3) Patent CN201510167670.7 uses oriented nanofibers in the inner layer and random nanofibers in the outer layer; the inner layer fibers are finer and denser as a blood-proof layer, while the outer layer fibers are coarser and have larger pores for smooth muscle cells to migrate and grow; the oriented nanofibers have The fibers have a highly consistent arrangement direction, which can promote endothelial cell adhesion and migration through contact guidance, and the combination with cells or growth factors can further promote cell proliferation and differentiation. The outer layer of fluffy and macroporous fibers is conducive to the arrangement and extension of vascular smooth muscle cells (VSMCs); (4) Patent CN201910633942.6 uses ordered fibers as the inner layer of small-caliber artificial blood vessels to provide binding sites for vascular endothelial cells and induce their polar growth; bacterial cellulose is used as the outer layer, which is conducive to cell penetration and reserves living space for vascular smooth muscle cells.

[0005] The above-mentioned patents CN201510167670.7, CN202010012857.0 and CN202010012857.0 use electrospinning as the main method to prepare small-caliber artificial blood vessels. Although they can simulate the fiber and porous structure of the natural extracellular matrix and provide suitable adhesion sites for cells, the pore size of the electrospun blood vessels is small, making it difficult to achieve cell invasive growth; the layer-by-layer bonding strength at the interface between the inner and outer layers is low, and they are easily delaminated during degradation, posing a risk of clogging blood vessels; their bending performance is insufficient, and kinks will occur at joints that require frequent bending and twisting. In most cases, the final electrospun tube does not have sufficient mechanical properties to resist liquid leakage under hemodynamics and pressure after graft implantation. In addition, the fiber diameter of small-caliber artificial blood vessels prepared by electrospinning is smaller than that of strong melt and solution spinning. The mechanical properties under long-term blood flow impact are not enough to support the stability of vascular structure, and the limited biocompatibility is insufficient to promote vascular remodeling, which limits the application of electrospinning in in vivo transplantation materials. The preparation process of small-caliber artificial blood vessels prepared by electrospinning and other processes is complicated, difficult to operate, and time-consuming. Cellulose with different advanced structures can be obtained by bacterial culture. By adjusting the culture conditions, bacterial cellulose with different chemical properties can also be obtained, but its wet strength is poor, there is a risk of collapse after blood vessel replacement, and its culture environment requirements are high, and its biosafety needs to be improved.

[0006] To overcome the above problems, researchers have tried a variety of improvement methods. Textile technology and weaving technology have also been explored for the preparation of artificial blood vessels, but these technologies can only make single-layer tubular structures and it is difficult to achieve complex multi-layer structures. Although a double-layer structure can be formed by adjusting the textile process, such as changing the number of weaving layers and changing the weaving pattern, there is no interaction between the fibers or yarns between the layers, and the bonding strength is basically zero, which is not suitable for cell growth and vascular regeneration.

[0007] In order to improve the bending resistance of artificial blood vessels, the existing method for the bending resistance of polymer artificial blood vessels is corrugation post-treatment. This method is suitable for materials that are easily deformed by heat or force. A spring-shaped spiral ring structure is formed on the tubular structure, which has good bending resistance. The anti-bending principle is similar to spring deformation, but the corrugation treatment is generally only for polymer materials, especially fiber materials. The latest research uses 3D printing or melt spinning to make polymer materials into spring-shaped spiral ring structures. When subjected to external forces, the polymer skeleton spring structure is prone to compression deformation on the inside and tensile deformation on the outside. The overall structure has certain bending resistance. However, when the structure is in high pressure or high flow rate environment, the stability of the spring-shaped structure is limited, and the structure is prone to deformation or fracture. Repeated bending is prone to fatigue damage, resulting in deformation or failure of the spring structure. In addition, the small-caliber artificial blood vessels prepared by this method have low bonding strength between layers, are prone to delamination when degraded after transplantation, and have the risk of forming vascular false lumens or causing intimal hyperplasia. And corrugation treatment is mostly used for specific material types, which limits its application in more new materials.

[0008] The document (Frontiers in Materials, 2020, 7: 220) and the patent CN202011391665.1 disclose a small-caliber artificial blood vessel with good bending resistance and a preparation method thereof, including a three-layer structure, wherein both the inner and outer layers are irregular electrospun fiber membranes, the inner and outer electrospun membranes are used as dense layers to prevent blood seepage, and the middle layer is provided with a spring-shaped spiral ring structure composed of a polymer material. The combination of the two layers and the spiral ring structure can effectively improve the bending resistance of small-caliber artificial blood vessels. However, the small-caliber artificial blood vessels prepared by this method have low bonding strength between layers, are easily delaminated when degraded after transplantation, and have the risk of forming a vascular false lumen or causing intimal hyperplasia.

[0009] In addition, in vitro tissue engineering technology, bioprinting technology and self-assembly technology are also commonly used methods for preparing artificial blood vessels.

[0010] Although in vitro tissue engineering technology can culture and assemble different types of cells, it is costly and has a long culture period. The assembly of different types of cells may be limited, and it is difficult to ensure their uniform distribution in the overall structure. Therefore, problems such as uneven cell distribution or unclear cell hierarchy may occur.

[0011] Bioprinting technology can print cells and biomaterials in a predetermined three-dimensional structure, thereby preparing artificial blood vessels with complex structures and multi-layered tissues. By printing different types of cells and biomaterials layer by layer, artificial blood vessels with multi-layer structures can be constructed. However, the preparation process is relatively complicated, requiring the use of special equipment and techniques, and the preparation cost is high. Bioprinted artificial blood vessels have no fiber interspersed or nested structures and generally have poor mechanical properties. At the same time, cell damage or death may occur during the printing process, affecting the biological activity and long-term stability of the artificial blood vessels. In addition, printing accuracy and speed may limit the complexity and size of the structure.

[0012] Self-assembly technology uses the adhesion and growth characteristics of cells to assemble into multilayer structures without external interference. By culturing different types of cells together on appropriate scaffolds or matrices, they can be encouraged to spontaneously assemble into multilayer structures, forming structures similar to natural blood vessels. However, self-assembly technology is limited by the characteristics of cells themselves, and the self-assembly process may be uncontrollable, resulting in uncertainty in the formation of multilayer structures and difficulty in accurately controlling the morphology and performance of the structure.

[0013] Therefore, it is of great significance to study an integrated bionic double-layer anti-bending artificial blood vessel and a preparation method thereof to solve the problems existing in the prior art. Summary of the invention

[0014] The purpose of the present invention is to solve the problems existing in the prior art and to provide an integrated bionic double-layer anti-bending artificial blood vessel and a preparation method thereof.

[0015] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0016] An integrated bionic double-layer anti-bending artificial blood vessel is a hollow tubular fabric structure consisting of an inner layer and an outer layer. The inner surface of the inner layer is a smooth curved surface formed by interweaving multiple filaments, and the outer layer is a fluffy, porous and circumferentially oriented structure formed by the single filaments in the multiple filaments on the outer surface of the inner layer being stretched and deformed. The fibers between the two layers are interspersed and connected with each other, and the inner and outer layers are a tightly connected integrated structure.

[0017] As the preferred technical solution:

[0018] In the integrated bionic double-layer anti-bending artificial blood vessel as described above, the average diameter of the inner layer pores is 5 to 10 μm, and the average diameter of the outer layer pores is 30 to 50 μm.

[0019] The integrated bionic double-layer anti-bending artificial blood vessel as described above has a surface density of 20 to 600 g / m 2 .

[0020] The integrated bionic double-layer anti-bending artificial blood vessel as described above has an inner diameter of 2 to 20 mm and a blood vessel wall thickness (referring to the overall thickness of the integrated bionic double-layer anti-bending artificial blood vessel) of 0.2 to 3 mm.

[0021] The integrated bionic double-layer anti-bending artificial blood vessel as described above does not collapse when bent to 180 degrees, that is, no obvious structural damage or permanent deformation occurs, and the minimum bending radius is 2 to 9.2 mm.

[0022] The present invention also provides a method for preparing an integrated bionic double-layer anti-bending artificial blood vessel as described in any of the above items, wherein a multifilament is used to form an artificial blood vessel tubular skeleton through a weaving method, and during the weaving forming process, the tension of some of the filament bundles is increased or decreased through tension control to form floating lines protruding from the surface of the fabric, and after the floating lines are pulled out, they are firstly drawn or hooked by a licker-in roller, and then subjected to a combing process, and finally post-processed to be shaped, so as to obtain an integrated bionic double-layer anti-bending artificial blood vessel;

[0023] The licker-in roller is a roller with a barbed structure on its surface. The barb structure is mainly used to effectively pull out the fibers during the napping process. The inner side of the barbs has edges, which can easily cut the pulled out fibers. The carding process uses a carding frame, which is a roller with a surface covered with vertical steel needles, to comb the messy fibers into the same direction (circumferential direction).

[0024] The post-processing setting process can be heat setting or solution setting.

[0025] Heat setting: Use high temperature to heat set the braided tube with circumferentially oriented outer layer, heat the thermoplastic fiber to make it flexible, make the macromolecular chain segments move and rearrange, and fix the shape after rapid water bath cooling (room temperature 20°C); the heat setting temperature is set between the fiber Tg and Tm, and the time is 2 to 8 hours.

[0026] Solution setting: Soak the product after the combing process in a room temperature fixative for 5 to 10 minutes. There is no chemical reaction between the artificial vascular fiber and the fixative. After taking it out, rinse it with the corresponding organic solvent or deionized water and dry it at room temperature. The fixative used is a low melting point polymer (a solution dissolved in an organic solvent at high temperature and then cooled to room temperature), or a protein and polysaccharide solution (such as silk, collagen, gelatin, hyaluronic acid, etc.) with good biocompatibility, certain viscosity and adhesion, and can be set after drying. The low melting point polymer can be polyvinyl alcohol (PVA), polycaprolactam (Nylon-6), degradable polyester (PLA), polybutylene adipate (PBT), polyvinyl stearate (EVA) or polycaprolactone (PCL), and the organic solvent can be ethyl acetate, amyl acetate, acetone, ethanol or xylene.

[0027] As the preferred technical solution:

[0028] In the preparation method of the integrated bionic double-layer anti-bending artificial blood vessel as described above, the multifilament specification is 20D-500D, the multifilament is an untwisted yarn bundle, and the fineness of the single yarn in the multifilament is between 10 and 30 μm.

[0029] In the preparation method of an integrated bionic double-layer anti-bending artificial blood vessel as described above, the number of floating threads accounts for 1 / 2 to 2 / 3 of the total number of fibers in the multifilament; the length of the fibers used to form the outer layer structure obtained after napping or hooking is between 0.5 and 20 mm.

[0030] The present invention also provides a method for preparing an integrated bionic double-layer anti-bending artificial blood vessel as described in any one of the above items, wherein a multifilament is knitted or weaved to form an artificial blood vessel tubular skeleton, a plating tissue is added to the base tissue during the knitting or weaving process, the fibers in the plating tissue are first cut, then combed, and finally post-processed to form the integrated bionic double-layer anti-bending artificial blood vessel;

[0031] The carding process uses a carding frame that is a roller with vertical steel needles on its surface.

[0032] As the preferred technical solution:

[0033] In the method for preparing an integrated bionic double-layer anti-bending artificial blood vessel as described above, the number of fibers in the added yarn tissue accounts for 1 / 3 to 1 / 2 of the total number of fibers in the multifilament.

[0034] Principle of the invention:

[0035] The integrated bionic double-layer anti-bending artificial blood vessel of the present invention has a smooth curved inner layer, and the inner layer fibers are evenly distributed (the even distribution of the inner layer fibers can be analyzed by microscopic image analysis of the spacing and density of the fibers, such as Fig.12 As shown in the figure, the spacing and arrangement of the fibers on the inner surface are consistent, and the pores are relatively small, which can reduce blood permeability to a certain extent, provide more adhesion sites for endothelial cells, and accelerate the formation of the endothelial layer; the outer layer is fluffy and porous, circumferentially oriented fibers, the fibers are arranged perpendicular to the blood flow direction, and the fiber mesh has large pores, which can guide the migration of smooth muscle cells, thus forming a vascular stent with functional partitions. The inner and outer layers are an integrated structure, and the fibers are interlaced between the inner and outer layers. There is no problem of stratification of the bonding surface during the degradation process, and it does not collapse when bent 180 degrees.

[0036] The integrated bionic double-layer anti-bending artificial blood vessel of the present invention is deformed when bending. Figure 2As shown, the vascular wall far from the center of the curvature is stretched, and the vascular wall close to the center of the curvature is squeezed. Stretched vascular wall: The inner braided structure has greater mobility. When stretched, the braiding angle becomes smaller, and the vascular wall is elongated. Since the outer fibers are arranged in a circumferential orientation, there is no mechanical constraint between each other. The outer fibers can undergo a large lateral migration, and the vascular wall is not easily ruptured. Squeezed vascular wall: The inner layer braiding angle increases when subjected to force, and the vascular wall shrinks. The outer fibers are arranged in a circumferential orientation and are not interwoven, so they are easy to separate. They slip under the action of squeezing. When the force continues to increase, the fibers inside the bending point are easily squeezed out, thereby resisting bending deformation, reducing the bending radius, and not easily bending.

[0037] Beneficial effects:

[0038] (1) The integrated bionic double-layer anti-bending artificial blood vessel of the present invention can simulate the complex structure of natural blood vessels and has a significant guiding effect on specific vascular cells; the fibers of the circumferentially oriented fluffy structure of the outer layer of the double-layer blood vessel are conducive to the orientation and extension of vascular smooth muscle cells (VSMCs), and promote the proliferation and connection of fibroblasts. The smooth surface of the inner layer inhibits platelet adhesion and activation and fibrinogen adsorption, promotes the formation of endothelial cell (EC) monolayer, and reduces the risk of thrombosis and immune rejection. At the same time, the double-layer structure can provide better mechanical properties, such as anti-bending properties, thereby reducing the risk of fracture and damage after vascular transplantation; at the same time, the two layers of the integrated double-layer anti-bending artificial blood vessel have good connection and natural transition, which can avoid the stratification problem of multi-layer artificial blood vessels during the regeneration process.

[0039] (2) The present invention provides an integrated bionic double-layer anti-bending artificial blood vessel, in which the inner and outer layers of the artificial blood vessel are an integrated structure. The design of the double-layer structure artificial blood vessel not only promotes the regeneration of the multi-layer structure of the blood vessel, but also eliminates the problem of stratification of the bonding surface during degradation, thereby providing a stable structure for cell adhesion and growth during the process of blood vessel regeneration; at the same time, it also improves its anti-bending performance, meeting the anti-bending clinical application requirements of special parts of the shoulder, elbow, and knee joints, as well as the carotid and femoral arteries.

[0040] (3) The method for preparing an integrated bionic double-layer anti-bending artificial blood vessel of the present invention has a simple preparation process, the artificial blood vessel is integrally formed, and has good anti-bending performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 The scanning electron microscope images of the integrated bionic double-layer anti-bending artificial blood vessel of Example 2 are as follows: the left image is the inner layer, and the right image is the outer layer;

[0042] Figure 2 It is a schematic diagram of the axial cross section of the integrated bionic double-layer anti-bending artificial blood vessel when it is bent; R is the bending radius;

[0043] Figure 3A schematic diagram of the integrated bionic double-layer anti-bending artificial blood vessel skeleton structure using a weaving method;

[0044] Figure 4 The schematic diagram of the integrated bionic double-layer anti-bending artificial blood vessel skeleton structure using the weaving method;

[0045] Figure 5 A schematic diagram of the integrated bionic double-layer anti-bending artificial blood vessel skeleton structure using a knitting method;

[0046] Figure 6 The wire hooking procedure for preparing artificial blood vessels;

[0047] Figure 7 The velvet cutting procedure when preparing for artificial blood vessels;

[0048] Figure 8 The combing procedure when preparing for vascular prosthesis;

[0049] Fig. 9 This is a scanning electron microscope image of the integrated bionic double-layer anti-bending artificial blood vessel of Example 2;

[0050] Fig.10 This is a schematic diagram of the cross section of an integrated bionic double-layer anti-bending artificial blood vessel;

[0051] Fig.11 This is a schematic diagram of the integrated bionic double-layer anti-bending artificial blood vessel;

[0052] Fig.12 The integrated bionic double-layer anti-bending artificial blood vessel fiber is evenly distributed in the inner layer structure of Example 2;

[0053] Fig.13 This is a cross-sectional electron microscope image of the outer layer fibers leading out from the inner layer in the integrated structure of the artificial blood vessel in Example 2;

[0054] Among them, 1-outer layer, 2-inner layer outer surface, 3-inner layer inner surface, 4-artificial blood vessel tubular skeleton, 5-licker-in roller, 6-pile cutting blade, 7-combing frame, 8-integrated bionic double-layer anti-bending artificial blood vessel, 9-inner layer. DETAILED DESCRIPTION

[0055] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0056] The test methods involved in the performance indicators in the embodiments and comparative examples of the present invention are as follows:

[0057] Porosity: Tested with reference to YY / T 0500-2021 "Cardiovascular Implants Vascular Prostheses Tubular Vascular Grafts and Vascular Patches". The porosity is determined by the pore weight method, and the mass per unit area of ​​the vascular prosthesis sample is compared with the density and wall thickness of the product. The porosity of the outer layer of the integrated bionic double-layer anti-bending artificial blood vessel can quantitatively characterize the fluffy and porous structural characteristics. The porosity of the outer layer of the integrated bionic double-layer anti-bending artificial blood vessel in the present invention is 47.34-63.63%.

[0058] Insertion density and connection strength: Cut the integrated double-layer anti-bending artificial blood vessel to prepare a sample with an area of ​​1cm×1cm, trim the longer fibers on the surface, calculate the number of outer layer fibers per unit area through scanning electron microscopy or optical microscope images, and quantify the fiber insertion density. The insertion density of the integrated bionic double-layer anti-bending artificial blood vessel with an inner diameter of 2mm is about 3040 fibers / cm 2 .

[0059] Connection strength: Refer to YY / T 0500-2021 "Cardiovascular Implants Vascular Prosthesis Tubular Vascular Grafts and Vascular Patches" to test the connection strength. The test was conducted using a multifunctional strength tester for medical textiles, using model YG(B)026G-500. The upper and lower clamping devices clamped the inner and outer fibers of the blood vessel respectively, with a stretching speed of 50 mm / min. The average value of the breaking force was recorded 5 times to calculate the connection strength. The connection strength of the inner and outer layers of the integrated bionic double-layer anti-bending artificial blood vessel in the present invention is 2.57-6.54 MPa.

[0060] Example 1

[0061] A method for preparing an integrated bionic double-layer anti-bending artificial blood vessel, the specific steps are as follows:

[0062] (1) Figure 3 As shown, a multifilament is used to form an artificial blood vessel tubular skeleton through a 32-spindle braiding machine. During the braiding process, the tension of some of the tows is changed from 3N to 5N through tension control, forming floating lines protruding from the surface of the fabric.

[0063] Among them, the specification of multifilament is 300D, the multifilament is an untwisted yarn bundle, the fineness of the single yarn in the multifilament is 26.3μm; the number of floating lines accounts for 1 / 2 of the total number of fibers in the multifilament;

[0064] (2) After the floating line is pulled out, it is roughened by a licker-in roller. The length of the fiber used to form the outer layer structure obtained after roughening is between 0.5 and 15 mm. The licker-in roller is a roller with a barbed structure on its surface.

[0065] (3) After the product of step (2) is subjected to a combing process, the outer layer of the circumferentially oriented braided tube is heat-set at a high temperature of 180° C. for 5 hours, and then cooled in a water bath to obtain an integrated bionic double-layer anti-bending artificial blood vessel;

[0066] Among them, the carding frame used in the carding process is a roller with vertical steel needles on the surface.

[0067] like Figure 2 , 10 As shown in Figures 1 to 11, the final integrated bionic double-layer anti-bending artificial blood vessel is a hollow tubular fabric structure, consisting of an inner layer 9 and an outer layer 1. The inner surface 3 of the inner layer is a smooth curved surface formed by interweaving multifilaments, and the outer layer 1 is a fluffy, porous and circumferentially oriented structure formed by the single filaments in the multifilaments of the inner layer outer surface 2 being stretched and deformed by hooks. The fibers between the two layers are interlaced and connected with each other, and the inner and outer layers are a tightly connected integral structure; the average diameter of the inner layer pores is 8μm, and the average diameter of the outer layer pores is 40μm; the porosity of the outer layer is 53.97%; the surface density of the integrated bionic double-layer anti-bending artificial blood vessel is 75g / m 2 ; The inner diameter of the integrated bionic double-layer anti-bending artificial blood vessel is 2mm, and the thickness of the blood vessel wall is 0.6mm; the integrated bionic double-layer anti-bending artificial blood vessel does not collapse when bent to 180 degrees, and the minimum bending radius is 2mm; the connection strength of the inner and outer layers of the integrated bionic double-layer anti-bending artificial blood vessel is 3.56MPa.

[0068] Example 2

[0069] A method for preparing an integrated bionic double-layer anti-bending artificial blood vessel, the specific steps are as follows:

[0070] (1) Figure 3 , 6 As shown, a multifilament is used to form an artificial blood vessel tubular skeleton 4 through a 48-spindle braiding machine. During the braiding process, the tension of some of the yarn bundles is changed from 5.5N to 3N through tension control, forming floating lines protruding from the surface of the fabric;

[0071] Among them, the specification of multifilament is 450D, the multifilament is an untwisted yarn bundle, the fineness of the single yarn in the multifilament is 10.8μm; the number of floating lines accounts for 1 / 2 of the total number of fibers in the multifilament;

[0072] (2) Figure 6 As shown, after the floating line is drawn out, it is hooked by the licker-in roller 5, and the length of the fiber obtained after the hooking for forming the outer layer structure is between 5 and 20 mm;

[0073] Wherein, the licker-in roller 5 is a roller with barbed structures on its surface;

[0074] (3) After the product of step (2) is combed, it is immersed in a room temperature fixing solution (5 wt % polyvinyl alcohol solution, Sigma-Aldrich brand: P8136) for 10 minutes, taken out, rinsed with deionized water and dried at room temperature to obtain an integrated bionic double-layer anti-bending artificial blood vessel;

[0075] Among them, the carding frame used in the carding process is a roller with vertical steel needles on the surface.

[0076] like Figure 1 , Fig. 9 , Fig.12 , Fig.13 As shown in the figure, the finally obtained integrated bionic double-layer anti-bending artificial blood vessel is a hollow tubular fabric structure, which consists of an inner layer and an outer layer. The inner surface of the inner layer is a smooth curved surface formed by interweaving multifilaments, and the outer layer is a fluffy, porous and circumferentially oriented structure formed by the single filaments in the multifilaments on the outer surface of the inner layer being stretched and deformed by hooks. The fibers between the two layers are interlaced and connected with each other, and the inner and outer layers are a tightly connected integral structure; the average diameter of the pores in the inner layer is 8μm, and the average diameter of the pores in the outer layer is 40μm; the porosity of the outer layer is 58.53%; the surface density of the integrated bionic double-layer anti-bending artificial blood vessel is 62g / m 2 ; The inner diameter of the integrated bionic double-layer anti-bending artificial blood vessel is 4mm, and the thickness of the blood vessel wall is 0.5mm; the integrated bionic double-layer anti-bending artificial blood vessel does not collapse when bent to 180 degrees, and the minimum bending radius is 2.7mm; the connection strength of the inner and outer layers of the integrated bionic double-layer anti-bending artificial blood vessel is 4.37MPa.

[0077] Example 3

[0078] A method for preparing an integrated bionic double-layer anti-bending artificial blood vessel, the specific steps are as follows:

[0079] like Figure 5 As shown, a multifilament is used to form an artificial blood vessel tubular skeleton through a knitting method, and a yarn-filling tissue is added to the basic tissue during the knitting forming process, such as Figures 7-8 As shown, the fibers in the plaited yarn tissue are firstly cut with a tuft cutting blade 6, then subjected to a combing process, and finally subjected to a heat setting treatment at a high temperature of 170° C. for 2 hours, and then cooled in a water bath to obtain an integrated bionic double-layer anti-bending artificial blood vessel;

[0080] The specification of the multifilament is 256D, the multifilament is an untwisted bundle, and the fineness of the single filament in the multifilament is 15.63 μm; the number of fiber roots in the added yarn organization accounts for 1 / 3 of the total number of fiber roots in the multifilament; the carding frame 7 used in the carding process is a roller with vertical steel needles on the surface.

[0081] The final integrated bionic double-layer anti-bending artificial blood vessel is a hollow tubular fabric structure, consisting of an inner layer and an outer layer. The inner surface of the inner layer is a smooth curved surface formed by interweaving multifilaments, and the outer layer is a fluffy, porous and circumferentially oriented structure formed by the single filaments in the multifilaments on the outer surface of the inner layer being stretched and deformed. The fibers between the two layers are interlaced and connected with each other, and the inner and outer layers are a tightly connected integrated structure; the average diameter of the inner layer pores is 10μm, and the average diameter of the outer layer pores is 50μm; the porosity of the outer layer is 63.63%; the surface density of the integrated bionic double-layer anti-bending artificial blood vessel is 234g / m 2 ; The inner diameter of the integrated bionic double-layer anti-bending artificial blood vessel is 6mm, and the thickness of the blood vessel wall is 1.5mm; the integrated bionic double-layer anti-bending artificial blood vessel does not collapse when bent to 180 degrees, and the minimum bending radius is 6.7mm; the connection strength of the inner and outer layers of the integrated bionic double-layer anti-bending artificial blood vessel is 2.57MPa.

[0082] Example 4

[0083] A method for preparing an integrated bionic double-layer anti-bending artificial blood vessel, the specific steps are as follows:

[0084] like Figure 4 As shown, a tubular skeleton of an artificial blood vessel is formed by a weaving method using multifilaments, and a plating tissue is added to the basic tissue during the weaving process. The fibers in the plating tissue are first cut, then subjected to a combing process, and finally subjected to a heat setting treatment at a high temperature of 170°C for 2 hours, and then cooled in a water bath to obtain an integrated bionic double-layer anti-bending artificial blood vessel;

[0085] Among them, the specification of multifilament is 43.6D, the multifilament is an untwisted yarn bundle, and the fineness of single yarn in the multifilament is 12.87μm; the number of fiber roots in the added yarn organization accounts for 1 / 2 of the total number of fiber roots in the multifilament; the carding frame used in the carding process is a roller with vertical steel needles on the surface.

[0086] The final integrated bionic double-layer anti-bending artificial blood vessel is a hollow tubular fabric structure, consisting of an inner layer and an outer layer. The inner surface of the inner layer is a smooth curved surface formed by interweaving multifilaments, and the outer layer is a fluffy, porous and circumferentially oriented structure formed by the single filaments in the multifilaments on the outer surface of the inner layer being stretched and deformed. The fibers between the two layers are interlaced and connected with each other, and the inner and outer layers are a tightly connected integrated structure; the average diameter of the inner layer pores is 5μm, and the average diameter of the outer layer pores is 30μm; the porosity of the outer layer is 47.34%; the surface density of the integrated bionic double-layer anti-bending artificial blood vessel is 164g / m 2 ; The inner diameter of the integrated bionic double-layer anti-bending artificial blood vessel is 20mm, and the thickness of the blood vessel wall is 1mm; the integrated bionic double-layer anti-bending artificial blood vessel does not collapse when bent to 180 degrees, and the minimum bending radius is 9.2mm; the connection strength of the inner and outer layers of the integrated bionic double-layer anti-bending artificial blood vessel is 6.54MPa.

Claims

1. An integrated bionic double-layer anti-bending artificial blood vessel, which is a hollow tubular fabric structure, consisting of an inner layer and an outer layer, characterized in that: The inner surface of the inner layer is a smooth curved surface formed by interweaving multifilaments, and the outer layer is a fluffy, porous and circumferentially oriented structure formed by the single filaments in the multifilaments on the outer surface of the inner layer being stretched and deformed. The inner and outer layers are a tightly connected integrated structure.

2. The integrated bionic double-layer anti-bending artificial blood vessel according to claim 1, characterized in that: The average diameter of the inner layer pores is 5 to 10 μm, and the average diameter of the outer layer pores is 30 to 50 μm.

3. The integrated bionic double-layer anti-bending artificial blood vessel according to claim 2 is characterized in that: The surface density of the integrated bionic double-layer anti-bending artificial blood vessel is 20-600g / m 2 .

4. The integrated bionic double-layer anti-bending artificial blood vessel according to claim 3 is characterized in that: The inner diameter of the integrated bionic double-layer anti-bending artificial blood vessel is 2 to 20 mm, and the thickness of the blood vessel wall is 0.2 to 3 mm.

5. The integrated bionic double-layer anti-bending artificial blood vessel according to claim 4, characterized in that: The integrated bionic double-layer anti-bending artificial blood vessel does not collapse when bent to 180 degrees, and the minimum bending radius is 2 to 9.2 mm.

6. A method for preparing an integrated bionic double-layer anti-bending artificial blood vessel according to any one of claims 1 to 5, characterized in that: The tubular skeleton of an artificial blood vessel is formed by weaving a multifilament yarn. During the weaving process, the tension of some yarn bundles is increased or decreased by tension control to form floating lines protruding from the surface of the fabric. After the floating lines are pulled out, they are firstly drawn or hooked by a licker-in roller, then combed, and finally post-processed to be shaped, so as to obtain an integrated bionic double-layer anti-bending artificial blood vessel. The licker-in roller is a roller with a barbed structure on its surface; the carding frame used in the carding process is a roller with a vertical steel needle on its surface.

7. The method for preparing an integrated bionic double-layer anti-bending artificial blood vessel according to claim 6, characterized in that: The specifications of multifilament yarn are 20D~500D. The multifilament yarn is an untwisted yarn bundle, and the fineness of the single yarn in the multifilament yarn is between 10 and 30μm.

8. The method for preparing an integrated bionic double-layer anti-bending artificial blood vessel according to claim 6, characterized in that: The number of floating threads accounts for 1 / 2 to 2 / 3 of the total number of fibers in the multifilament; the length of the fibers obtained after napping or hooking for forming the outer layer structure is between 0.5 and 20 mm.

9. The method for preparing an integrated bionic double-layer anti-bending artificial blood vessel according to any one of claims 1 to 5, characterized in that: The tubular skeleton of an artificial blood vessel is formed by knitting or weaving a multifilament, and a plating tissue is added to the basic tissue during the knitting or weaving process. The fibers in the plating tissue are first cut, then combed, and finally post-processed to form an integrated bionic double-layer anti-bending artificial blood vessel. The carding process uses a carding frame that is a roller with vertical steel needles on its surface.

10. The method for preparing an integrated bionic double-layer anti-bending artificial blood vessel according to claim 9, characterized in that: The number of fibers in the added yarn structure accounts for 1 / 3 to 1 / 2 of the total number of fibers in the multifilament.

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