An artificial blood vessel joint and a method for manufacturing the same

Abstract

The application discloses an artificial blood vessel joint and a preparation method thereof. The blood vessel joint adopts a carbon-based material as a base body, a double-layer composite coating with PyC and Ag-doped DLC and an Ag-doped DLC coating are prepared on the inner wall and the outer wall respectively, and the blood vessel joint is obtained; the inner wall of the blood vessel joint is smooth and compact, which is beneficial to blood circulation; the outer wall is a porous Ag-doped DLC coating, which is beneficial to biological fixation with tissues; the Ag-doped DLC coating endows the blood vessel joint with good antibacterial property, reduces inflammation, and can improve the adverse reaction of the human body caused by friction and powder loss after the blood vessel joint is implanted into the human body.

Description

Technical Field

[0001] This invention relates to an artificial vascular connector, specifically to a carbon-based vascular connector with an Ag-DLC-doped outer wall and a PyC and Ag-DLC-doped double-layer composite coating on the inner wall, and also to its preparation method, belonging to the field of biomedical materials technology. Background Technology

[0002] Surgical procedures involving the aorta, such as organ transplantation or aortic damage, necessitate arterial reconstruction, requiring temporary cessation of cardiac blood circulation and suture stitching. This carries a risk of tearing and is time-consuming, potentially causing cerebral hypoxia. Researchers have devised a treatment method that involves first fixing rigid rings at both ends of a flexible artificial blood vessel, then inserting it into the aorta. The artificial blood vessel is then secured inside the aorta from the outside with a bandage, eliminating the need for sutures and reducing the risk of tissue tearing. These rings are typically made of titanium, which has poor biocompatibility, is heavy, and prone to clotting, requiring long-term anticoagulant medication after implantation. Carbon-based materials are excellent biomaterials with good biocompatibility, light weight, and significant anticoagulant properties. However, they are brittle, especially when used in the fabrication of small components, exhibiting significant local brittleness that can cause powder detachment and secondary damage. Furthermore, while carbon-based materials are inert, their porous nature increases the risk of bacteria entering human tissues and bloodstreams during use, potentially leading to inflammation. Summary of the Invention

[0003] To address the shortcomings of existing technologies, the first objective of this invention is to provide an artificial vascular connector. The connector's matrix material is a carbon-based material, which has good blood compatibility and is suitable for rapid docking during organ transplantation. Its inner wall is a smooth and dense PyC and Ag-DLC-doped double-layer composite coating, which facilitates blood flow. The outer wall is a porous Ag-DLC-doped coating, which facilitates biological fixation with tissues. Furthermore, the Ag-DLC-doped coating imparts good antibacterial properties, reducing inflammation. It can also improve adverse reactions in the human body caused by friction and powder shedding after implantation.

[0004] Another objective of this invention is to provide a method for preparing an artificial vascular connector, which is simple to operate, easy to control precisely, and conducive to industrial production.

[0005] To achieve the above-mentioned technical objectives, the present invention provides an artificial blood vessel connector with a hollow tubular structure, wherein the artificial blood vessel connector is made of carbon-based material; the outer wall of the artificial blood vessel connector has an Ag-DLC-doped coating, and the inner wall has a PyC and Ag-DLC-doped double-layer composite coating.

[0006] The vascular connector of this invention uses a carbon-based material as the matrix, with an outer surface coated with Ag-DLC and an inner surface coated with a PyC coating and an Ag-DLC dual-layer composite coating. This effectively solves the defects of carbon-based materials in the fabrication of small-sized parts, such as local brittleness, easy powder shedding leading to secondary damage, and the tendency of carbon-based materials to carry bacteria into human tissues during use, causing inflammation. The vascular connector, using a carbon-based material as the matrix, exhibits excellent biocompatibility, is lightweight, and possesses anticoagulant properties. The inner surface of the vascular connector consists of a PyC coating and an Ag-DLC-doped double-layer composite coating. The PyC coating is primarily deposited on the surface of the carbon-based material matrix, effectively sealing the surface pores and facilitating the formation of a smooth and dense PyC and Ag-DLC double-layer composite coating, which promotes blood flow. The introduction of the PyC coating also enhances the adhesion between the carbon-based material and the Ag-DLC coating. The Ag-DLC coating exhibits good biocompatibility, surface hardness, and friction resistance, and possesses antibacterial properties. In particular, the Ag element incorporated into the diamond-like carbon (DLC) film layer further strengthens its bond with the carbon-based material, significantly improving the overall adhesion between the composite coating and the carbon-based matrix. The outer surface of the vascular connector, lacking a PyC coating, primarily consists of a porous Ag-DLC-doped coating, which facilitates biological fixation with tissue. The Ag-DLC-doped coatings on both the inner and outer surfaces of the vascular connector impart excellent antibacterial properties, reducing inflammation and mitigating adverse reactions caused by friction and powdering after implantation.

[0007] As a preferred embodiment, the thickness of the Ag-DLC-doped coating is 1–3 μm. If the coating thickness is too thin, its antibacterial effect is limited; if the coating thickness is too thick, it can easily block pores, which is not conducive to biological fixation with tissues.

[0008] As a preferred embodiment, the thickness of the PyC coating in the PyC and Ag-DLC bilayer composite coating is 10–50 μm, and the thickness of the Ag-DLC coating is 1–3 μm. If the PyC coating is too thin, it cannot form a complete continuous coating; if the coating is too thick, the surface roughness increases, and it is easy to peel off from the carbon-based material surface.

[0009] As a preferred embodiment, the Ag-doped DLC coating contains 1-15% Ag by mass. Appropriately increasing the Ag doping amount can improve the adhesion between the Ag-doped DLC coating and the substrate, and enhance the mechanical properties of the Ag-doped DLC coating. However, excessively high Ag doping ratios are harmful to the human body and can cause Ag poisoning, while excessively low Ag doping ratios lack bactericidal properties and cannot effectively improve the biocompatibility and mechanical properties of the substrate.

[0010] This invention also provides a method for preparing an artificial vascular connector, which includes the following steps:

[0011] 1) Machining carbon-based materials to form vascular connector blanks;

[0012] 2) Deposit a PyC coating on the surface of the blank;

[0013] 3) Machining the outer surface of the blank to remove the PyC coating;

[0014] 4) A coating with Ag-DLC is deposited on the surface of the blank to obtain the final product.

[0015] As a preferred embodiment, the PyC coating is generated by chemical vapor deposition, and the PyC coating generation conditions are: deposition for 10 to 50 hours at a temperature of 1000 to 1800°C under the condition of introducing a gaseous carbon source.

[0016] As a preferred embodiment, the Ag-DLC doped film is deposited using a combination of unbalanced mid-frequency magnetron sputtering and DC arc PECVD. The deposition conditions for the Ag-DLC doped film are: Ar gas flow rate of 20–100 sccm, carbon source gas flow rate of 10–100 sccm, and vacuum degree of 1.0 × 10⁻⁶. -1 ~4.0×10 -1 Pa, ion source power of 0.5–3 kW, Ag palladium power of 0.1–1 kW, Ag target purity of not less than 99.9 wt%, workpiece negative bias voltage of 50–600 V, deposition time of 30–540 min. Common gaseous carbon sources include acetylene.

[0017] The carbon-based material of the present invention is prepared by existing conventional methods, as illustrated below:

[0018] 1) A tubular carbon fiber preform is formed by needle-punching a carbon fiber mesh or a wide bundle of carbon fiber with the carbon fiber mesh. The carbon fiber is a 3mm wide 1k carbon fiber bundle, a 5mm wide 2k carbon fiber bundle, an 8mm wide 3k carbon fiber bundle, a 15mm wide 6k carbon fiber bundle, or a 25mm wide 12k carbon fiber, or a mixture thereof; the carbon fiber mesh has a strength of 10–40 g / m². 2 The mesh layer density is 20-40 layers / cm.

[0019] 2) Composite tube blanks with a matrix of carbon or a matrix of carbon and silicon carbide are prepared by chemical vapor deposition and / or liquid phase impregnation-pyrolysis, with a density of 1.3–2.5 g / cm³. 3 .

[0020] The process for preparing carbon matrix by chemical vapor deposition is as follows: carbon fiber preforms are placed in a deposition furnace, and carbon-containing gas sources (natural gas, methane, propylene, propane, etc., with nitrogen or hydrogen as diluent gas, and the flow ratio of carbon source gas to diluent gas is 1:0 to 3) are introduced at a temperature of 800 to 1350°C, and deposition is carried out for 50 to 250 hours.

[0021] The impregnation-pyrolysis process for preparing the carbon matrix involves the following steps: The carbon fiber preform undergoes vacuum pressure impregnation with resin (furan, phenolic resin, and furfuryl ketone, etc.) or asphalt (petroleum asphalt, coal tar pitch), followed by curing and pyrolysis (resin: 900–1050℃, atmospheric pressure; asphalt: 750–850℃, 50–200 MPa) for densification. The impregnation pressure is 2.0–6.0 MPa, and the impregnation time is 2–10 h; the curing temperature is 160–230℃, and the curing time is 10–50 h; the pyrolysis time is 2–20 h.

[0022] The process for preparing silicon carbide substrate by chemical vapor deposition is as follows: carbon fiber preform is placed in a deposition furnace and deposited at a temperature of 1000℃~1300℃ for 30~120 hours with a gas source (trichloromethylsilane, hydrogen as carrier gas and dilution gas, and the flow ratio of trichloromethylsilane to hydrogen is 1:1~20).

[0023] The liquid-phase impregnation-pyrolysis process for preparing silicon carbide matrix involves the following densification processes: vacuum pressure impregnation with silicon-containing precursors (polycarbosilane PCS, polymethylsilane PMS), curing, and pyrolysis. The impregnation pressure is 1.0–6.0 MPa, and the impregnation time is 2–10 h; the curing temperature is 120–240℃, and the curing time is 10–60 h; the pyrolysis temperature is 750–1150℃, and the time is 2–20 h; the ceramization temperature is 1150–1650℃, and the time is 2–10 h.

[0024] The artificial blood vessel connector of the present invention is prepared by the following method:

[0025] 1) Carbon-based materials are processed into blood vessel blanks through mechanical cutting, grinding and other processes;

[0026] 2) A pyrolytic carbon coating (PyC coating) is prepared on the surface of the blood vessel blank. The thickness of the pyrolytic carbon coating is 10-50 μm. The PyC coating is generated by chemical vapor deposition. The generation conditions are as follows: a gas source (natural gas, methane, etc. are used as carbon source gas, and nitrogen or hydrogen is used as dilution gas, with a flow ratio of carbon source gas to dilution gas of 1:0-10) is used, and the deposition is carried out at a temperature of 1000℃-1800℃ for 10-50 hours.

[0027] 3) Machin the outer diameter of the blood vessel blank and remove the PyC coating from the outer surface;

[0028] 4) An Ag-DLC-doped coating is deposited on the surface of the blood vessel blank to obtain the blood vessel connector product;

[0029] The thickness of the Ag-doped DLC film is 1–3 μm, and the Ag mass percentage content in the Ag-doped DLC coating is 1–15%.

[0030] Preparation of Ag-DLC-doped composite coating: The cleaned workpiece is placed in a coating equipment combining unbalanced medium-frequency magnetron sputtering and DC arc PECVD. The system is evacuated to the working vacuum level, impurity gases are removed from the furnace, and then the workpiece is cleaned with an ion source. Subsequently, the Ag-DLC-doped coating is prepared.

[0031] The process for cleaning the blank is as follows: the blank is ultrasonically cleaned with purified water and ethanol in succession. The cleaning temperature is 20-32℃ and the cleaning time is 10-30min. After cleaning, the blank is dried and ready for use.

[0032] The process for removing impurity gases from the furnace is as follows: Ar gas is introduced into the vacuum chamber at a flow rate of 50–120 sccm, and the vacuum degree is 4.0 × 10⁻⁶. -1 ~7.0×10 -1 Pa, the negative bias voltage of the workpiece is 400-800V, and the degassing time is 10-30min.

[0033] The process for cleaning workpieces using an ion source is as follows: Ar gas flow rate is 60–100 sccm, and vacuum degree is 3.0 × 10⁻⁶. -1 ~6.0×10 -1 Pa, ion source power of 0.9-1.2kW, workpiece negative bias voltage of 400-800V, cleaning time of 15-40min.

[0034] The process for preparing Ag-doped DLC coatings is as follows: Ar gas flow rate is 20–100 sccm, gas carbon source flow rate is 10–100 sccm, and vacuum degree is 1.0 × 10⁻⁶. -1 ~4.0×10 -1 Pa, ion source power of 0.5–3 kW, Ag palladium power of 0.1–1 kW, Ag target purity of 99.9 wt%, workpiece negative bias voltage of 50–600 V, and deposition time of 30–540 min.

[0035] The equipment used in this invention to prepare silver-doped diamond-like composite coatings is the HCSH-DLC650 equipment from Guangdong Huicheng Vacuum Technology Co., Ltd., the PVD850-DLC equipment from Dongguan Huanan New Material Research Co., Ltd., or the DLC-800 equipment from Qingdao Youbaiyu Vacuum Equipment Co., Ltd. This equipment is a coating equipment that combines unbalanced medium-frequency magnetron sputtering and DC arc PECVD technology.

[0036] Compared with existing technologies, the beneficial technical effects of the present invention are as follows:

[0037] 1) The vascular connector of the present invention uses a carbon-based material matrix, which has good blood compatibility, reduces coagulation, and is suitable for rapid docking during organ transplantation.

[0038] 2) The inner and outer surfaces of the vascular connector of the present invention are coated with Ag-DLC, which not only endows the vascular connector with good biocompatibility, surface hardness and friction performance, but also has good antibacterial properties, which can reduce the occurrence of inflammation. Compared with the coating without Ag, the antibacterial property is increased by 15-40%, and at the same time, it can improve the adverse human reactions caused by friction powdering after the vascular connector is implanted in the human body.

[0039] 3) The Ag-DLC coating on the surface of the vascular connector of the present invention incorporates Ag elements into the diamond-like carbon film layer, making it more tightly bonded to the carbon-based material and greatly improving the bonding force between the entire composite coating and the carbon-based material matrix.

[0040] 4) The inner surface of the vascular connector of the present invention is a PyC coating and an Ag-DLC-doped double-layer composite coating, which has the characteristics of being smooth and dense, which is conducive to blood flow, while the outer surface of the vascular connector is a porous Ag-DLC-doped coating, which is conducive to biological fixation with tissue.

[0041] 5) The vascular connector of the present invention deposits a PyC coating on the surface of a carbon-based material and then deposits Ag-DLC. The PyC coating seals the pores on the surface of the carbon-based material, thereby facilitating the formation of a smooth and dense PyC and Ag-DLC double-layer composite coating. At the same time, the introduction of the PyC coating helps to improve the bonding force between the carbon-based material and the Ag-DLC coating.

[0042] 6) The vascular connector method of the present invention is simple to operate, easy to control precisely, and conducive to industrial production. Attached Figure Description

[0043] Figure 1 The diagram shows an artificial blood vessel connector; the left image is an overall schematic diagram, and the right image is a cross-sectional schematic diagram; where 1 is a carbon-based material tube, 2 is a PyC coating + Ag-DLC doped double-layer composite coating, and 3 is an Ag-DLC doped coating. Detailed Implementation

[0044] To make the present invention clearer, the present invention will be described in detail below with reference to specific embodiments. The specific embodiments described herein are only used to further explain the present invention in detail, and do not limit the scope of protection of the claims of the present invention.

[0045] Performance testing: In the following examples, the mechanical properties of the coating were tested using nanoindentation and nanoscratching methods; the coefficient of friction of the film was measured using a ball-and-disc friction tester; and the improvement of the coating's biocompatibility with the substrate was verified using endothelial cell proliferation and E. coli survival experiments.

[0046] The specific preparation method of the carbon-based material in the following specific embodiments is as follows:

[0047] 1) Use 15mm wide 6k carbon fiber bundles with 20g / m 2 Carbon fiber mesh is needle-punched into tubular carbon fiber preforms with a mesh layer density of 25 layers / cm.

[0048] 2) The carbon fiber preform was placed in a deposition furnace, and propylene and nitrogen gas were introduced at 950℃ (propylene to nitrogen flow rate ratio of 1:2) for 150 h to prepare a preform with a density of 1.5 g / cm³. 3 Carbon-based material preform.

[0049] Example 1

[0050] 1) Carbon-based material blanks are processed into blood vessel blanks through mechanical cutting, grinding and other processes;

[0051] 2) Methane and nitrogen were used as gas sources (methane to nitrogen flow ratio of 1:5), and deposition was carried out at 1500℃ for 20h; a PyC coating was prepared on the surface of the blood vessel blank, and the thickness of the pyrolytic carbon coating was 30μm.

[0052] 3) Machin the outer diameter of the blood vessel blank and remove the PyC coating from the outer surface;

[0053] 4) An Ag-DLC-doped coating is deposited on the surface of the blood vessel blank to obtain the blood vessel connector product. Specific steps for the Ag-DLC-doped coating in step 4) are as follows:

[0054] A. Cleaning the billet: The billet is ultrasonically cleaned with deionized water and anhydrous ethanol in succession. The cleaning temperature is 28℃ and the cleaning time is 20min. After cleaning, it is dried and ready for use.

[0055] B. Place the cleaned preform in a coating equipment that combines unbalanced medium-frequency magnetron sputtering and DC arc PECVD, and evacuate it to the working vacuum level.

[0056] C. Remove impurities from the furnace: Introduce Ar gas into the vacuum chamber at a flow rate of 100 sccm, maintaining a vacuum level of 5.0 × 10⁻⁶. -1 Pa, the workpiece negative bias voltage is 800V, and the degassing time is 20min.

[0057] D. Ion source cleaning of workpiece: Ar gas flow rate is 80 sccm, vacuum degree is 4.0 × 10⁻⁶ -1 Pa, ion source power is 1kW, workpiece negative bias voltage is 800V, cleaning time is 30min.

[0058] E. Preparation of Ag-doped DLC coating: Ar gas flow rate 80 sccm, acetylene gas flow rate 100 sccm, vacuum degree 2.0 × 10⁻⁶ - 1 Pa, ion source power 1kW, Ag target power 0.4kW, Ag target purity 99.9wt%, workpiece negative bias voltage 600V, coating time 180min.

[0059] G. An Ag-doped DLC coating was obtained, with an overall Ag content of 5% and a thickness of 1 μm.

[0060] The Ag-DLC-doped coating prepared in this embodiment exhibits high adhesion between itself and the carbon material vascular connector, with a value of 9N. This reduces the wear rate between the carbon material vascular connectors, resulting in a friction coefficient of 0.08 and a wear rate of 6.8 × 10⁻⁶. -7 mm 3 / N·m。 Effectively improves the antibacterial properties between carbon material vascular connectors. Compared with uncoated carbon material vascular connectors, in this example, the survival rate of Escherichia coli in the bacterial survival experiment of carbon material vascular connectors with Ag-DLC coating decreased from 100% to 85%, and the endothelial cell proliferation rate in the endothelial cell proliferation experiment increased from 70% to 87%.

[0061] Example 2

[0062] Steps 1) to 3) are the same as in Example 1.

[0063] Step 4) Specific steps for the Ag-DLC doped coating:

[0064] A. Cleaning the billet: The billet is ultrasonically cleaned with deionized water and anhydrous ethanol in succession. The cleaning temperature is 28℃ and the cleaning time is 20min. After cleaning, it is dried and ready for use.

[0065] B. Place the cleaned preform in a coating equipment that combines unbalanced medium-frequency magnetron sputtering and DC arc PECVD, and evacuate it to the working vacuum level.

[0066] C. Remove impurities from the furnace: Introduce Ar gas into the vacuum chamber at a flow rate of 100 sccm, maintaining a vacuum level of 5.0 × 10⁻⁶. -1 Pa, the workpiece negative bias voltage is 800V, and the degassing time is 20min.

[0067] D. Ion source cleaning of workpiece: Ar gas flow rate is 80 sccm, vacuum degree is 4.0 × 10⁻⁶ -1 Pa, ion source power is 1kW, workpiece negative bias voltage is 800V, cleaning time is 30min.

[0068] E. Preparation of Ag-doped DLC coating: Ar gas flow rate 60 sccm, acetylene gas flow rate 100 sccm, vacuum degree 2.0 × 10⁻⁶ -1 Pa, ion source power of 1kW, silver target power of 0.3kW, Ag target purity of 99.9wt%, workpiece negative bias voltage of 600V, coating time of 420min.

[0069] G. An Ag-DLC-doped coating was obtained, with an overall silver content of 8% and a thickness of 2.4 μm.

[0070] The Ag-DLC coating prepared in this embodiment exhibits high adhesion between itself and the carbon material vascular connector, with a value of 12 N. This reduces the wear rate between the carbon material vascular connectors, resulting in a friction coefficient of 0.06 and a wear rate of 5.2 × 10⁻⁶. -7 mm 3 / N·m。 Effectively improves the antibacterial properties between carbon material vascular connectors. Compared with uncoated carbon material vascular connectors, in this embodiment, the survival rate of Escherichia coli in the bacterial survival experiment of carbon material vascular connectors with Ag-DLC coating decreased from 100% to 80%, and the endothelial cell proliferation rate in the endothelial cell proliferation experiment increased from 70% to 93%.

[0071] Comparative Example 1

[0072] The only difference between this comparative example and Example 1 is that Ag element was not incorporated into the DLC film.

[0073] The undoped Ag DLC ​​coating prepared in this comparative example exhibits low adhesion between the coating and the carbon-based vascular connector. Its strength is 3 N, the coefficient of friction is 0.12, and the wear rate is 8.9 × 10⁻⁶. -7 mm 3 / N·m. In the bacterial survival experiment of the coated carbon material vascular connector prepared in this comparative example, the survival rate of Escherichia coli decreased from 100% to 96%, while the endothelial cell proliferation experiment increased from 70% to 76%.

[0074] Table 1 Comparison of Performance Test Results

[0075]

Claims

1. An artificial blood vessel connector having a hollow tubular structure, characterized in that: The artificial blood vessel connector is made of carbon-based material; the outer wall of the artificial blood vessel connector has an Ag-DLC-doped coating, and the inner wall has a PyC and Ag-DLC-doped double-layer composite coating; the thickness of the Ag-DLC-doped coating on the outer wall of the artificial blood vessel connector is 1~3μm; the thickness of the PyC coating in the PyC and Ag-DLC-doped double-layer composite coating is 10~50μm, and the thickness of the Ag-DLC-doped coating is 1~3μm; the silver content in the Ag-DLC-doped coating is 1~15% by mass.

2. The method for preparing an artificial blood vessel connector according to claim 1, characterized in that: Includes the following steps: 1) Machining carbon-based materials to form vascular connector blanks; 2) Deposit a PyC coating on the surface of the blank; 3) Machining the outer surface of the blank to remove the PyC coating; 4) A coating containing Ag-DLC is deposited on the surface of the blank to obtain the final product.

3. The method for preparing an artificial blood vessel connector according to claim 2, characterized in that: The PyC coating is generated by chemical vapor deposition. The PyC coating is generated under the following conditions: under the condition of introducing a gaseous carbon source, at a temperature of 1000~1800℃, for 10~50 hours.

4. The method for preparing an artificial blood vessel connector according to claim 2, characterized in that: The Ag-doped DLC coating was deposited using a combination of unbalanced mid-frequency magnetron sputtering and DC arc PECVD. The deposition conditions for the Ag-doped DLC coating were: Ar gas flow rate 20~100 sccm, gas carbon source flow rate 10~100 sccm, and vacuum degree 1.0×10⁻⁶. -1 ~4.0×10 -1 Pa, ion source power of 0.5~3kW, Ag target power of 0.1~1kW, Ag target purity of not less than 99.9wt%, workpiece negative bias voltage of 50~600V, and plating time of 30~540min.

Images