A bioelastomeric vascular graft and methods of making and using the same

Abstract

This invention discloses a bioelastomer artificial blood vessel, its preparation method, and its application. It relates to the field of artificial blood vessel technology, comprising a bioelastomer artificial blood vessel, an artificial blood vessel matrix, and a hydrogel network. The artificial blood vessel matrix is ​​composed of continuous fibers formed by electrospinning, interwoven to form a three-dimensional porous fiber network structure. The hydrogel network is embedded on the outer surface of the fibers, forming an interpenetrating network (IPN) or semi-interpenetrating network structure. The material of the artificial blood vessel matrix is ​​a biodegradable polyester, which allows for a relatively gradual change in the mechanical properties of the artificial blood vessel during degradation, avoiding abrupt changes in mechanical properties caused by material degradation. This helps maintain the stability of the vascular structure and provides conditions for the gradual participation of host tissue in vascular structure reconstruction.

Description

Technical Field

[0001] This invention relates to the field of artificial blood vessel technology, and in particular to a bioelastomer artificial blood vessel, its preparation method, and its application. Background Technology

[0002] Cardiovascular disease has become the leading cause of death among humans, and vascular replacement is one of the effective means to combat it. Artificial blood vessels have important applications in the treatment of coronary artery, peripheral artery, and carotid artery diseases. However, existing artificial blood vessels generally suffer from problems such as decreased patency and insufficient functional reconstruction during in vivo application. The fundamental reason for this is that artificial blood vessels cannot simulate the characteristics of natural elastic blood vessels at the levels of mechanical behavior and tissue evolution.

[0003] Natural blood vessels, especially arteries, are essentially a typical elastic tissue, capable of reversible deformation under pulsating blood flow and maintaining a stable mechanical state through the coordinated remodeling of smooth muscle cells and the extracellular matrix. Therefore, if artificial blood vessels cannot exhibit the characteristics of an elastic body, they often lead to blood flow disturbances, abnormal tissue proliferation, or functional decline due to mechanical mismatch.

[0004] Currently, most of the artificial blood vessel materials used in clinical practice and research remain at the level of "structural replacement" rather than "elastomer functional replacement." For example, artificial blood vessels made from non-degradable or weakly degradable polymer materials can maintain their luminal shape for a long time, but their mechanical behavior differs significantly from that of natural elastomer blood vessels, making functional reconstruction difficult.

[0005] In the research of biodegradable artificial blood vessels, synthetic polymer materials (such as polycaprolactone, polylactic acid, etc.) are widely used, but the following shortcomings still exist: 1) Some materials are too rigid and it is difficult to simulate the elastomeric behavior of natural blood vessels; 2) Some materials have an unbalanced degradation rate, resulting in premature loss or long-term retention of elastic function; 3) During the degradation process of materials, the elastic load-bearing function cannot be smoothly transferred to the host tissue.

[0006] Therefore, constructing an artificial blood vessel that can gradually complete the transfer of elastomer functions in vivo is a key problem that urgently needs to be solved in the field of artificial blood vessels. Summary of the Invention

[0007] The main objective of this invention is to propose an artificial blood vessel, its preparation method, and its application, aiming to solve the problems in the prior art where the mechanical behavior of artificial blood vessels differs significantly from that of natural elastomer blood vessels, making it difficult to achieve elastomer functional replacement and the asynchronous material degradation and elastic reconstruction.

[0008] To achieve the above objectives, the present invention proposes a bioelastomer artificial blood vessel, an artificial blood vessel matrix, the artificial blood vessel matrix having multiple fibers; and

[0009] A hydrogel network is embedded on the outer surface of the fiber, and the material of the artificial blood vessel matrix is ​​a biodegradable polyester.

[0010] In one embodiment, the material of the artificial blood vessel matrix includes at least one selected from poly(L-lactide-caprolactone) copolymer, polylactic acid-glycolic acid copolymer, biodegradable polyurethane, and polyglycerol sebate; and / or, The hydrogel network is made of at least one of polyvinyl alcohol, polyacrylic acid, and polyacrylamide.

[0011] In one embodiment, the inner diameter of the bioelastomer artificial blood vessel is 2-3 mm.

[0012] This invention also provides a method for preparing an artificial blood vessel, comprising the following steps: S10. Obtain the artificial blood vessel substrate; S20, a solution of the material for preparing the hydrogel network; S30. Using interfacial penetration technology, the solution of the hydrogel network material is permeated into the surface of the artificial blood vessel matrix to obtain a bio-elastomer artificial blood vessel.

[0013] In one embodiment, in step S20, the mass-volume ratio of the PVA hydrogel solution is 8% to 12%.

[0014] In one embodiment, step S30 includes: S301, Prepare the crosslinking agent; S302. The artificial blood vessel matrix is ​​mixed with the crosslinking agent so that the outer surface of the artificial blood vessel matrix is ​​embedded in the surface of the artificial blood vessel matrix, and then mixed with a solution of the hydrogel network material so that the crosslinking agent crosslinks with the hydrogel network material to obtain a bio-elastomer artificial blood vessel.

[0015] In one embodiment, step S301 includes: synthesizing a bis-quaternary ammonium salt by quaternization reaction of a tertiary amine with a haloalkanes, purifying the bis-quaternary ammonium salt by precipitation using solvent polarity differences, and obtaining a crosslinking agent.

[0016] This invention provides an application of the aforementioned bioelastomer artificial blood vessel, which includes the bioelastomer artificial blood vessel as described above or a product prepared by the aforementioned method of preparing bioelastomer artificial blood vessels.

[0017] In the technical solution of this invention, the present invention aims to provide an elastomeric artificial blood vessel, an artificial blood vessel matrix composed of multiple fibers, and a hydrogel network embedded and enriched on the outer surface of the fibers to form a hydrogel network penetrating the matrix. The two form an interpenetrating network (IPN) or semi-interpenetrating network structure. This structure enables the artificial blood vessel to gradually reduce its elastic contribution over time after implantation, rather than being suddenly lost, due to the controllable degradation mechanism of the biodegradable polyester material of the artificial blood vessel matrix. This not only maintains initial elastic support but also, during the gradual degradation of the artificial blood vessel's elasticity, the pre-formed hydrogel network can induce host cell ingrowth, constructing an elastic scaffold dominated by new tissue in situ within the matrix pores. This ensures that the mechanical properties of the artificial blood vessel change relatively smoothly throughout the degradation process, avoiding abrupt changes in mechanical properties caused by material degradation. This is beneficial for maintaining the stability of the vascular structure and provides conditions for the gradual participation of host tissue in vascular structure reconstruction. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present 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 the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the electron microscopy results of the materials prepared in Example 1 and Comparative Example 1 of the present invention. Figure 2 This is a schematic diagram illustrating the staining evaluation of tissue regeneration using the materials prepared in Example 1 and Comparative Example 1 of the present invention. Figure 3 This is a schematic diagram of CD31 and α-SMA immunofluorescence staining of the materials prepared in Example 1 and Comparative Example 1 of the present invention; Figure 4 This is a schematic diagram of histological observation of the material prepared in Example 1 of the present invention; Figure 5 This is a schematic diagram showing the staining results of the material prepared in Example 1 of the present invention. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially. Furthermore, the meaning of "and / or" throughout the text includes three parallel solutions; for example, "A and / or B" includes solution A, or solution B, or a solution where both A and B are satisfied simultaneously. In addition, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Currently, most of the artificial blood vessel materials used in clinical practice and research remain at the level of "structural replacement" rather than "elastomer functional replacement." For example, artificial blood vessels made from non-degradable or weakly degradable polymer materials can maintain their luminal shape for a long time, but their mechanical behavior differs significantly from that of natural elastomer blood vessels, making functional reconstruction difficult.

[0022] In the research of biodegradable artificial blood vessels, synthetic polymer materials (such as polycaprolactone, polylactic acid, etc.) are widely used, but the following shortcomings still exist: 1) Some materials are too rigid and it is difficult to simulate the elastomeric behavior of natural blood vessels; 2) Some materials have an unbalanced degradation rate, resulting in premature loss or long-term retention of elastic function; 3) During the degradation process of materials, the elastic load-bearing function cannot be smoothly transferred to the host tissue.

[0023] Therefore, constructing an artificial blood vessel that can gradually complete the transfer of elastomer functions in vivo is a key problem that urgently needs to be solved in the field of artificial blood vessels.

[0024] In view of this, the present invention provides a bioelastomer artificial blood vessel, comprising: An artificial blood vessel matrix, wherein the artificial blood vessel matrix has multiple fibers; and A hydrogel network is embedded on the outer surface of the fiber, and the material of the artificial blood vessel matrix is ​​a biodegradable polyester.

[0025] In the technical solution of this invention, the present invention aims to provide an elastomeric artificial blood vessel, an artificial blood vessel matrix composed of multiple fibers, and a hydrogel network embedded and enriched on the outer surface of the fibers to form a hydrogel network penetrating the matrix. The two form an interpenetrating network (IPN) or semi-interpenetrating network structure. This structure enables the artificial blood vessel to gradually reduce its elastic contribution over time after implantation, rather than being suddenly lost, due to the controllable degradation mechanism of the biodegradable polyester material of the artificial blood vessel matrix. This not only maintains initial elastic support but also, during the gradual degradation of the artificial blood vessel's elasticity, the pre-formed hydrogel network can induce host cell ingrowth, constructing an elastic scaffold dominated by new tissue in situ within the matrix pores. This results in a relatively gradual change in the mechanical properties of the artificial blood vessel during degradation, avoiding abrupt changes in mechanical properties caused by material degradation. This is beneficial for maintaining the stability of the vascular structure and provides conditions for the gradual participation of host tissue in vascular structure reconstruction.

[0026] It should be noted that hydrogel networks refer to three-dimensional network structures formed by hydrophilic polymer chains (such as PVA) through physical cross-linking (such as hydrogen bonds, crystalline regions) or chemical cross-linking (such as covalent bonds).

[0027] Furthermore, the biodegradable polyester can be precisely controlled by adjusting the ratio of L-propiolactone to caprolactone to a molar ratio of L-lactide to ε-caprolactone of 20:80~40:60, preferably 25:75~35:65, and most preferably 30:70. Specifically, in PLCL, when the ratio of L-propiolactone to caprolactone is 70:30, the prepared artificial blood vessel still maintains an intact tubular structure, indicating that reducing the proportion of lactic acid significantly slows down the degradation rate of the material and allows it to maintain the necessary mechanical support time in vivo. The above results show that the present invention achieves effective control of the degradation rate of artificial blood vessels by adjusting the monomer ratio of PLCL.

[0028] Understandably, if the material degrades too quickly, the tissue will rupture before it can grow properly; if it degrades too slowly, the tissue may grow properly but be shielded from stress by the material, leading to tissue shrinkage (stress shielding effect). When PLCL degrades completely or mostly, the remaining PVA network can serve as a temporary microscaffold, or the PVA may also degrade partially, and the space will eventually be filled by the host's regenerated autologous tissue. At this point, the elasticity of the blood vessel begins to be maintained by the newly formed elastic fibers and collagen network, achieving a seamless switch from "artificial" to "natural".

[0029] In some embodiments of the present invention, the material of the artificial blood vessel matrix includes at least one of poly(L-lactide-caprolactone) copolymer, polylactic acid-glycolic acid copolymer (PLGA), biodegradable polyurethane (PU), and polyglycerol sebacate (PGS). For example, PLCL acts as a framework, providing similar high resilience and flexibility to natural blood vessels, such as elastin, to ensure that the blood vessel can expand with the heartbeat in the early stage of implantation and avoid collapse.

[0030] The hydrogel network is made of at least one of polyvinyl alcohol, polyacrylic acid, and polyacrylamide.

[0031] That is, the materials of the hydrogel network include polyvinyl alcohol, polyethylene glycol (PEG) and its derivatives, polyacrylic acid (PAA), polyacrylamide (PAM) or combinations thereof, which are embedded in the surface of each fiber in PLCL and cross-linked to form an interpenetrating network (IPN) or a semi-interpenetrating network. PVA not only enhances the radial strength, but its hydrogel properties also simulate the water-containing environment of the blood vessel wall and improve blood compatibility.

[0032] This invention also provides a method for preparing a bioelastomer artificial blood vessel, comprising the following steps: S10. Obtain the artificial blood vessel substrate; S20, a solution of the material for preparing the hydrogel network; S30. Using interfacial penetration technology, the solution of the hydrogel network material is permeated onto the surface of the artificial blood vessel matrix to obtain a bio-elastomer artificial blood vessel. The technical solution provided by this invention first constructs a two-phase system by selecting a biodegradable polyester matrix in S10 and preparing a solution of the hydrogel network material in S20. Then, using the interfacial penetration technology in step S30, the solution of the hydrogel network material is precisely enriched on the surface of the artificial blood vessel matrix, forming an interpenetrating network (IPN) or semi-interpenetrating network structure that penetrates the matrix. This step is simple and easy to operate, and ensures that the mechanical properties of the artificial blood vessel undergo a smooth gradient transition rather than abrupt fracture during the entire degradation process, perfectly matching the growth and remodeling rhythm of natural blood vessels, ultimately achieving a seamless evolution from "material support" to "autologous tissue regeneration".

[0033] It should be noted that since PLCL is a hydrophobic polyester, and methanol is highly volatile and has a limited penetration depth (depending on the soaking time), coupled with the large size of TSPBA molecules and a diffusion rate that is slower than the solvent evaporation or the time to reach equilibrium, TSPBA is mainly enriched on the outer surface and shallow layer of the scaffold, and it is difficult to penetrate into the core of the scaffold, which forms a state of "surface enrichment".

[0034] Specifically, the artificial blood vessel matrix of the present invention is composed of a PLCL nano / micro fiber network structure formed by electrospinning. Unlike dense bulk materials, electrospun materials are composed of a large number of interwoven independent fibers forming a three-dimensional porous network. Its overall mechanical properties come from the tensile strength of individual fibers, the interweaving and friction between fibers, and the network structure in which multiple fibers share the load. Therefore, when the material degrades in vivo, the entire structure does not break simultaneously. Instead, individual fibers gradually degrade or break, while the remaining fibers can continue to bear part of the load. This multi-fiber parallel load-bearing structure causes the overall mechanical properties of the artificial blood vessel to show a gradual decline trend, rather than the sudden overall fracture failure common in bulk materials.

[0035] Furthermore, this invention enables the PVA hydrogel to be uniformly embedded on the surface of each PLCL fiber, forming a continuous fiber-level coating structure. This structure has two important characteristics: 1. Fiber-level connection structure: PVA is not only embedded in the surface of individual fibers, but also forms a flexible connection interface between fibers, which enables additional bonding and synergistic deformation capabilities between adjacent fibers.

[0036] 2. Flexible buffer layer: PVA is a flexible hydrogel material. When the fiber undergoes local degradation or breakage, it can bear part of the stress and disperse the load in the local area through its flexible network.

[0037] Therefore, even if individual PLCL fibers degrade and break, the PVA interface layer can still maintain the connection between the fiber networks, thereby preventing the overall structure from suddenly becoming unstable.

[0038] In the technical solution of the present invention, in step S20, the material of the hydrogel network is PVA hydrogel, and the mass-volume ratio of the PVA hydrogel solution is 8%~12%.

[0039] In some embodiments of the present invention, step S30 includes: S301, Prepare the crosslinking agent; S302. The artificial blood vessel matrix is ​​mixed with the crosslinking agent so that the outer surface of the artificial blood vessel matrix is ​​embedded in the surface of the artificial blood vessel matrix, and then mixed with a solution of the hydrogel network material so that the crosslinking agent crosslinks with the hydrogel network material to obtain a bio-elastomer artificial blood vessel.

[0040] It should be noted that, taking PLCL as an example of an artificial blood vessel matrix, because PLCL is a hydrophobic polyester, and methanol is highly volatile and has limited penetration depth, coupled with the relatively large size of TSPBA molecules and its slower diffusion rate than the solvent evaporation or equilibrium time, TSPBA mainly accumulates on the outer surface and superficial layer of the artificial blood vessel matrix, forming a "surface enrichment" state. When a hydrogel precursor solution containing PVA (polyvinyl alcohol, rich in hydroxyl-OH groups) comes into contact with a PLCL scaffold loaded with TSPBA, TSPBA and PVA undergo a cross-linking reaction. This causes the PVA chains to not only physically wrap around the PLCL surface, but also to be chemically or strongly physically connected to the PLCL through the "molecular nail" of TSPBA. Ultimately, the PLCL framework and the PVA network interpenetrate and lock at the interface, forming a semi-interpenetrating network (Semi-IPN) or a fully interpenetrating network, which greatly improves the interfacial bonding force and prevents delamination.

[0041] In the technical solution of the present invention, step S301 includes: synthesizing a bis-quaternary ammonium salt by quaternization reaction of a tertiary amine with a haloalkanes, precipitating and purifying the bis-quaternary ammonium salt by utilizing the difference in solvent polarity, and obtaining a crosslinking agent.

[0042] Understandably, this step involves synthesizing a bisquaternary ammonium salt through the quaternization reaction of a tertiary amine with a haloalkanes, ultimately obtaining a cationic crosslinking agent that induces the formation of a polymer network through electrostatic interaction. Specifically, the obtained TSPBA molecule has a "double-headed" structure, containing two positively charged quaternary ammonium groups, which can act as a bridge to connect two different polymer chains, thereby forming a three-dimensional network structure and achieving physical crosslinking of the material.

[0043] This invention also provides an application of bioelastomer artificial blood vessels.

[0044] The technical solution of the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings. It should be understood that the following embodiments are only used to explain the present invention and are not intended to limit the present invention.

[0045] Example 1 A bioelastomer artificial blood vessel includes an artificial blood vessel matrix and a hydrogel network embedded in the outer surface of the artificial blood vessel matrix, wherein the material of the artificial blood vessel matrix is ​​a biodegradable polyester.

[0046] The preparation steps of the bioelastomer artificial blood vessel are as follows: 1. Synthesis of TSPBA 2 g of 4-bromomethylbenzene (Aladdin, Shanghai, China) was dissolved in 80 mL of N,N-dimethylformamide (DMF). 400 μL of N,N,N',N'-tetramethylpropane-1,3-diamine (TMPD, Aladdin, Shanghai, China) was added dropwise at 60 °C, and the mixture was stirred at 60 °C for 24 hours. The mixture was then treated with 200 mL of tetrahydrofuran, centrifuged at 3000 rpm for 5 min, and the precipitate was collected. The precipitate was then washed three times with 40 mL of tetrahydrofuran. The product was frozen at -80 °C for 2 h, followed by lyophilization for 48 h to obtain TSPBA solid. A 2% TSPBA methanol solution was prepared with 99.5% methanol and stored at 4 °C for later use as a crosslinking agent.

[0047] 2. Preparation of PVA solution Weigh out polyvinyl alcohol 1788 powder and prepare a 10% PVA solution with PBS at 85-95℃.

[0048] 3. Preparation of PLCL artificial blood vessels A 2.5mm iron rod was selected as the receiver. PLCL (purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., product number P299053 (CAS No.: 65408-67-5)) was dissolved in 1,1,1,3,3,3-hexafluoro-2-propanol (Aladdin, at a ratio of 15:100 (w / w)) and allowed to stand at room temperature for 10 hours. The electrospinning solution was loaded into a 10ml syringe using a 22-gauge needle and injected using a syringe pump (ET-1334H, Beijing Ucalery). The injection speed was 0.3mm / min, the voltage was 10 kV, and the injection distance was 24mm.

[0049] 4. Preparation of PLCL-PVA composite PLCL was washed sequentially with deionized water and isopropanol, dried in an oven for 1 hour, and then soaked in a methanol solution containing 2% TSPBA for 30 minutes. After soaking, the electrospinning scaffold was washed alternately with ethanol and water. The treated PLCL was then soaked in a 10% PVA solution for 30 minutes, followed by washing the scaffold three times with PBS solution to obtain PLCL-PVA.

[0050] Comparative Example 1 Compared with Example 1, Comparative Example 1 used only pure PLCL and did not include PVA solution, but was otherwise similar to Example 1.

[0051] Performance testing The tests for Example 1 and Comparative Example 1 were conducted as follows: 1) The fibrous structures of the elastomer artificial blood vessel prepared in Example 1 (PLCL-PVA of Example 1) and Comparative Example 1 (PLCL only) were observed using scanning electron microscopy (SEM, Nova NanoSEM 450, FEI, Amsterdam, Netherlands) at magnifications of 3000× and 8000×, respectively. Figure 1 It can be seen that the electrospun fiber structure of the PLCL group is clear and the boundaries are distinct. The fiber surface is relatively smooth and the fibers are mainly randomly interwoven. The outline of a single fiber is obvious, and no obvious fiber fusion or structural thickening phenomenon was observed. In contrast, the fiber morphology of the PLCL-PVA group has changed significantly. The overall fiber diameter is significantly larger than that of the PLCL group. The fiber surface shows a coating and thickening feature, and local thickening and adhesion phenomena appear at the fiber cross-connection points, forming a continuous connection structure.

[0052] The above results show that PVA successfully attaches to and coats the surface of PLCL fibers, forming a connection structure in the fiber interlacing area. This creates a network structure (interpenetrating network structure) on the basis of the PLCL fiber skeleton, where PLCL and PVA permeate and combine with each other. This proves that the processing method used in this invention can effectively introduce and stably combine PVA on the surface of PLCL fibers.

[0053] 2) Rabbits were anesthetized by intraperitoneal injection of 5-8 ml of 10% sodium pentobarbital solution. After complete anesthesia, the neck hair was shaved off with a razor, and the surgical site was thoroughly disinfected. The skin was incised to expose and isolate the left carotid artery. Heparin sodium solution was administered for anticoagulation via the marginal ear vein at a dose of 100 units / kg. A section of approximately 1.2 cm was removed between the clamps, and the PLCL-PVA composite artificial blood vessel of Example 1 and the PLCL artificial blood vessel of Comparative Example 1 (diameter 2.5 mm, length 1.2 cm) were sutured end-to-end to the rabbit carotid artery defect using 8-0 nylon sutures. After removing the clamps and restoring blood flow, the surgical site was closed with 4-0 nylon sutures. Treatment with sodium penicillin antibiotics (Jilin Huamu Animal Health Products Co., Ltd., Jilin, China) was administered at a dose of 100,000 units / kg / day for 3 consecutive days. Samples were collected three months later for subsequent experiments. 2.1 The specific steps for transverse staining include: ① The harvested artificial blood vessel grafts were stained with HE and Masson staining using the standard Seville HE / Massone staining procedure to assess tissue regeneration. The staining results are as follows: Figure 2The PLCL group grafts showed overall structural integrity, but almost no significant host tissue ingrowth was observed in the interstitial spaces, suggesting limited degradation and weak tissue integration capacity at this time point. In contrast, the PLCL-PVA group grafts maintained basic structural integrity while exhibiting localized material degradation, with significant host tissue ingrowth observed in the degradation areas. Masson staining further revealed more blue-stained collagen fiber deposits within the PLCL-PVA group graft walls, indicating that this material could promote extracellular matrix formation and tissue remodeling, while the PLCL group showed less collagen deposition.

[0054] ② Perform standard CD31 / α-SMA staining (Sevier) on the slides, including CD31 and α-SMA immunofluorescence staining. Results are as follows: Figure 3 The results showed that a continuous layer of CD31-positive endothelial cells formed on the surface of the graft lumen in the PLCL-PVA group, indicating that the graft lumen had achieved relatively complete endothelialization. Simultaneously, α-SMA staining revealed a relatively uniform and continuous layer of smooth muscle cells in both the inner and outer layers of the graft wall, suggesting that the vascular wall structure was gradually reconstructing into a natural vascular-like structure. In contrast, only weaker CD31 and α-SMA signals were observed in the PLCL group, with no obvious continuous endothelial or smooth muscle layer formed.

[0055] 2.2 To further observe the spatial distribution of tissues and the reconstruction of the vascular wall structure in the artificial blood vessels, the experimental animals were euthanized and the vascular grafts from each group were removed three months after implantation. Subsequently, the vascular grafts in the PLCL-PVA group were longitudinally cut along their axis and flattened into a membranous structure to facilitate subsequent histological observation. Figure 4 This indicates that PLCL-PVA artificial blood vessels degraded three months after implantation, with randomized degradation areas accompanied by tissue infiltration, but without thrombosis or intimal hyperplasia. Subsequent histological and immunofluorescence staining analyses were performed, including the following steps: Three months after the PLCL-PVA vascular graft implantation in Example 1, all experimental rabbits were euthanized. The PLCL and PLCL-PVA composite vascular grafts were then carefully dissected and removed along the carotid artery and immediately fixed in 4% paraformaldehyde (PFA) for subsequent histological analysis and immunofluorescence staining. After fixation, the samples underwent gradient dehydration, paraffin embedding, and paraffin section preparation. The specific steps are as follows: HE staining: Paraffin sections were first dewaxed in xylene dewaxing solution, then sequentially immersed in a gradient of ethanol solutions (100%, 95%, 85%, 75%) for hydration, and rinsed with distilled water. Hematoxylin-eosin (HE) staining was then performed, involving hematoxylin staining, rinsing with running water, differentiation and blueing treatment, followed by eosin staining. After staining, the sections were dehydrated with a gradient of ethanol solutions and cleared with a clearing agent. Finally, they were mounted with neutral resin and observed under a light microscope. The images were analyzed to evaluate the tissue reaction around the graft and cell infiltration. The results are as follows: Figure 5 HE staining results showed extensive host cell infiltration around the graft wall. In some areas, voids formed by material degradation were observed, which were gradually filled by newly formed tissue, suggesting that significant tissue ingrowth accompanied the material degradation in vivo. Cells were mainly arranged along the blood vessel walls, exhibiting a certain tendency towards tissue organization.

[0056] Masson staining: Masson's trichrome staining is used to assess collagen fiber deposition and tissue remodeling after vascular graft implantation. After staining, the tissue undergoes dehydration, clearing, and mounting, followed by microscopic observation and image acquisition to analyze the formation of the collagen matrix in the newly formed tissue. Figure 5 Masson staining further revealed that there was significant collagen fiber deposition (blue staining) in the material degradation area and around the blood vessel wall. The collagen fibers were distributed in bundles or layers, forming a continuous structure with the surrounding newly formed tissue. This indicates that significant extracellular matrix reconstruction and fibrotic tissue formation have occurred around the graft, suggesting that the artificial blood vessel is transforming into a blood vessel-like tissue with tissue structure.

[0057] Immunofluorescence staining: Fixed PLCL-PVA composite artificial blood vessels from Example 1 were embedded in paraffin and sections were prepared. The paraffin sections were first dewaxed and hydrated, followed by antigen retrieval. Samples were blocked with 3% BSA solution for 30 min at room temperature to reduce non-specific binding, and then incubated with anti-CD31 antibody and anti-α-SMA antibody, respectively, to detect endothelial cell regeneration and smooth muscle cell reconstruction. After incubation, the corresponding fluorescently labeled secondary antibodies were added, and the cell nuclei were stained with DAPI (4′,6-diamidino-2-phenylindole). Finally, the samples were observed under a fluorescence microscope or confocal microscope, and the obtained fluorescence images were further analyzed. The results are as follows: Figure 5The results showed that CD31-positive cells were mainly distributed on the surface of the graft lumen, forming a continuous cell layer, indicating that a continuous endothelial cell covering layer had been formed in the graft lumen, achieving a relatively complete endothelialization process. At the same time, α-SMA staining showed that there were obvious α-SMA-positive smooth muscle cells on the inner and outer sides of the graft wall, arranged in bundles along the longitudinal direction of the blood vessel, forming a cell layer similar to the structure of the medial layer of natural blood vessels.

[0058] The above results indicate that, three months after implantation, the PLCL-PVA artificial blood vessel, while undergoing gradual material degradation, promotes host cell infiltration, collagen matrix deposition, and orderly reconstruction of vascular wall cells. A continuous endothelial cell layer forms in the lumen, while smooth muscle cells are directionally distributed in the vessel wall region, suggesting that this artificial blood vessel has good vascular-like tissue reconstruction capabilities and gradually forms a layered structure similar to natural blood vessels.

[0059] The above are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the patent protection scope of the present invention.

Claims

1. A bioelastic artificial blood vessel, characterized in that, include: An artificial blood vessel matrix, wherein the artificial blood vessel matrix has multiple fibers; and A hydrogel network is embedded on the outer surface of the fiber, and the material of the artificial blood vessel matrix is ​​a biodegradable polyester.

2. The bioelastomer artificial blood vessel as described in claim 1, characterized in that, The artificial blood vessel matrix is ​​made of at least one of poly(L-lactide-caprolactone) copolymer, polylactic acid-glycolic acid copolymer, biodegradable polyurethane, and polyglycerol sebate; and / or, The hydrogel network is made of at least one of polyvinyl alcohol, polyacrylic acid, and polyacrylamide.

3. The bioelastomer artificial blood vessel as described in claim 1, characterized in that, The inner diameter of the bioelastomer artificial blood vessel is 2-3 mm.

4. A method for preparing a bio-elastomer artificial blood vessel as described in any one of claims 1 to 3, characterized in that, Includes the following steps: S10. Obtain the artificial blood vessel substrate; S20, a solution of the material for preparing the hydrogel network; S30. Using interfacial penetration technology, the solution of the hydrogel network material is permeated into the surface of the artificial blood vessel matrix to obtain a bio-elastomer artificial blood vessel.

5. The method for preparing a bioelastomer artificial blood vessel as described in claim 4, characterized in that, In step S20, the material of the hydrogel network is PVA hydrogel, and the mass-volume ratio of the PVA hydrogel solution is 8%~12%.

6. The method for preparing artificial blood vessels as described in claim 4, characterized in that, Step S30 includes: S301, Prepare the crosslinking agent; S302. The artificial blood vessel matrix is ​​mixed with the crosslinking agent so that the outer surface of the artificial blood vessel matrix is ​​embedded in the surface of the artificial blood vessel matrix, and then mixed with a solution of the hydrogel network material so that the crosslinking agent crosslinks with the hydrogel network material to obtain a bio-elastomer artificial blood vessel.

7. The method for preparing a bioelastomer artificial blood vessel as described in claim 4, characterized in that, Step S301 includes: synthesizing a bis-quaternary ammonium salt by quaternization reaction of a tertiary amine with a haloalkanes, purifying the bis-quaternary ammonium salt by precipitation using solvent polarity differences, and obtaining a crosslinking agent.

8. An application of a bioelastomer artificial blood vessel, characterized in that, The bioelastomer artificial blood vessel is prepared by the bioelastomer artificial blood vessel as described in any one of claims 1 to 3 or by the method for preparing the bioelastomer artificial blood vessel as described in any one of claims 4 to 7.

Images