Composite intravascular stent and preparation method thereof

Abstract

The invention provides a composite intravascular stent and a preparation method thereof, and relates to the technical field of intravascular stents. The polymer / metal composite intravascular stent is prepared by combining a fused deposition manufacturing technology and a lamination manufacturing technology in 3D printing, two layers of polymer sheets are prepared by using an FDM technology, a layer of metal wire is added between the two layers of sheets, and then the polymer sheets are tightly bonded and completely cover the metal wire through a heating and pressurizing process, so that the polymer / metal composite intravascular stent is prepared. And then, bending the polymer / metal sheet into a tubular structure, and after the metal wires at the two ends are closed, knotting and fixing to obtain the composite intravascular stent. The composite intravascular stent has good radial supporting force, overcomes the defects of an existing composite intravascular stent containing a polymer material, and can meet the requirement of clinical use for the radial strength of the stent.

Description

Technical Field

[0001] The present invention relates to the technical field of vascular stents, and in particular to a composite vascular stent and a preparation method thereof. Background Art

[0002] Vascular stents are medical devices used to treat vascular stenosis or occlusion. They are placed inside blood vessels through interventional surgery and use their mesh or tubular structures to support the narrowed blood vessels, thereby expanding the blood vessel lumen to maintain smooth blood flow and reduce the risk of re-stenosis. They are widely used in the treatment of cardiovascular and cerebrovascular diseases and peripheral arterial disease.

[0003] Since the basic principle of the stent is to expand narrowed or occluded blood vessels through mechanical support, reduce vascular elastic retraction, and prevent restenosis. Therefore, the radial support force of the stent is one of its key performance parameters. However, since the modulus and strength of polymer materials are much lower than those of metal materials, the current composite vascular stents containing polymer materials have the problem of insufficient radial support force, which seriously restricts the use of biodegradable stents. Therefore, how to further improve the radial support force of composite vascular stents containing polymer materials is one of the technical problems that need to be solved urgently in this field. Summary of the invention

[0004] In view of this, the present invention provides a composite vascular stent and a preparation method thereof. The vascular stent of the present invention is a sinusoidal tubular stent, which is prepared by using the FDM technology and the lamination manufacturing technology. The composite vascular stent of the present invention has good radial support force, overcomes the shortcomings of the existing composite vascular stent containing polymer materials, and can meet the requirements of clinical use for the radial strength of the stent.

[0005] The first aspect of the present invention is to provide a method for preparing a composite vascular stent, which specifically comprises the following steps:

[0006] S1, sinusoidal stent design;

[0007] S2, preparing sinusoidal polymer sheets by fused deposition modeling (FDM) in 3D printing;

[0008] S3, laying the metal wire on a 0.2 mm thick polymer sheet, covering it with a 0.1 mm thick polymer sheet after heating, and hot pressing to bond the two layers of polymer sheets to obtain a polymer / metal sheet;

[0009] S4, bending the polymer / metal sheet along the short side into a tubular structure, bringing the iron wires at both ends together and tying them to fix, and wrapping the knotted part of the iron wires with molten polymer material to ensure that the iron wires are completely closed and not exposed, thereby obtaining a composite vascular stent;

[0010] Preferably, the polymer sheet is a PCL polymer sheet or a PPDO polymer sheet.

[0011] Preferably, when the polymer thin sheet is a PCL polymer thin sheet, the FDM parameters are set as follows: nozzle diameter 0.2 mm, filling rate 100%, nozzle temperature 130 °C, substrate temperature 45 °C, printing speed 100 mm / s.

[0012] Preferably, when the polymer thin sheet is a PPDO polymer thin sheet, the FDM parameters are set as follows: nozzle diameter 0.2 mm, filling rate 100%, nozzle temperature 180 °C, substrate temperature 80 °C, layer thickness 0.1 mm, printing speed 100 mm / s.

[0013] Preferably, the thicknesses of the layer polymer thin sheets are 0.1 mm and / or 0.2 mm respectively.

[0014] Preferably, the wire is an iron wire or a zinc wire, and the wire is in a sinusoidal shape consistent with the design.

[0015] Preferably, the diameter of the wire is 0.2 mm.

[0016] Preferably, the hot pressing temperature is 60 °C or 90 °C.

[0017] Preferably, the polymer material is PCL or PPDO.

[0018] The second aspect of the present invention is to provide a composite vascular stent, and the composite vascular stent is prepared by the above method.

[0019] The composite vascular stent of the present invention is used as a material for treating congenital heart disease-related vascular stenosis diseases.

[0020] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0021] The present invention combines a degradable wire with a degradable polymer to achieve the synergistic optimization of the radial support performance and biodegradability of the stent; through the precise control of the FDM and lamination process parameters, the uniformity of the thin sheet forming and the interfacial bonding strength are ensured; the design of the sinusoidal wave-shaped stent ring and the linear bridging unit ensures the compressibility and flexibility of the stent, which is beneficial to the smooth delivery through the delivery sheath and adaptation to the curved blood vessel; the use of molten polymer to wrap the wire joint reduces the irritation of the vascular intima, reduces the risk of restenosis and improves clinical safety. Description of the Drawings

[0022] The present invention will be further described below in conjunction with the description of the drawings.

[0023] Figure 1 It is a schematic diagram of the composite vascular stent, with the unit of mm. Detailed Embodiments

[0024] Next, in combination with the embodiments of the present invention, the technical solutions of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0025] The first aspect of the present invention is to provide a method for preparing a composite vascular stent, which specifically includes the following steps:

[0026] S1. Design of a sinusoidal stent;

[0027] S2. Prepare a sinusoidal polymer thin sheet by FDM;

[0028] In some specific embodiments of the present invention, the polymer thin sheet is a PCL polymer thin sheet or a PPDO polymer thin sheet; when the polymer thin sheet is a PCL polymer thin sheet, the FDM parameters are set as follows: nozzle diameter 0.2 mm, filling rate 100%, nozzle temperature 90°C - 140°C, preferably 130°C, substrate temperature 30°C - 45°C, preferably 45°C, printing speed 100 mm / s; when the polymer thin sheet is a PPDO polymer thin sheet, the FDM parameters are set as follows: nozzle diameter 0.2 mm, filling rate 100%, nozzle temperature 150°C - 190°C, preferably 180°C, substrate temperature 70°C - 90°C, preferably 80°C, layer thickness 0.1 mm, printing speed 100 mm / s; the thickness of the polymer thin sheet is 0.1 - 0.2 mm; in some preferred embodiments of the present invention, the thicknesses of the upper and lower polymer thin sheets are combinations of 0.1 mm and 0.1 mm, 0.1 mm and 0.2 mm, 0.2 mm and 0.2 mm respectively;

[0029] S3. Lay a metal wire on a 0.2 - mm - thick polymer thin sheet, heat it, cover it with a 0.1 - mm - thick polymer thin sheet, and perform hot pressing to bond the two layers of polymer thin sheets to obtain a polymer / metal sheet;

[0030] In some specific embodiments of the present invention, the metal wire is an iron wire or a zinc wire, the diameter of the metal wire is 0.2 mm, and the metal wire is sinusoidal and conforms to the design; the hot - pressing temperature is 55°C - 65°C or 90°C - 100°C. Specifically, when the polymer thin sheet is a PCL polymer thin sheet, the hot - pressing temperature is 55°C - 65°C, preferably 60°C, and the hot - pressing time is 20 - 45 s; when the polymer thin sheet is a PPDO polymer thin sheet, the hot - pressing temperature is 90°C - 100°C, preferably 90°C, and the hot - pressing time is 20 - 45 s;

[0031] S4. Bend the polymer / metal sheet along the short side into a tubular structure, bring the two ends of the iron wire together and tie a knot to fix it, and wrap the knot of the iron wire with the molten polymer material to ensure that the iron wire is completely enclosed and avoid exposure, thus obtaining a composite vascular stent;

[0032] In some specific embodiments of the present invention, the polymer material is PCL or PPDO, and the polymer material used in this step corresponds to the polymer thin sheet.

[0033] Fused Deposition Modeling (FDM) is a 3D printing technology based on the principle of material extrusion, which is widely used in rapid prototyping manufacturing, functional component preparation and biomedical fields.

[0034] The thermoplastic polymers (PCL, PPDO) are melted into a semi-fluid state through a high-temperature nozzle, and then are precisely extruded and deposited on the printing platform. A three-dimensional structure is formed by layer-by-layer stacking (layer thickness 0.1 - 0.2 mm). After the material cools, the material solidifies, and mechanical bonding is achieved through thermal bonding or molecular diffusion between layers. The lamination process bonds two polymer thin sheets by heating and pressing, wraps the degradable metal wire, and maintains the structural integrity of the stent. The present invention controls the process parameters of FDM and lamination to ensure the fluidity during the melt processing, enhance the interlayer adhesion, avoid warping and improve the forming accuracy and efficiency, thereby ensuring the structural density to meet the requirements of the vascular stent material.

[0035] The second aspect of the present invention is to provide a composite vascular stent, which is prepared by the above method.

[0036] The composite vascular stent of the present invention is used as a material for treating congenital heart disease-related vascular stenosis diseases.

[0037] To further illustrate the present invention, the following examples are used for detailed description. The raw materials used in the following examples of the present invention are all commercially available.

[0038] Unless otherwise specified, all tests are repeated 3 times, and the results are expressed as averages.

[0039] Example 1 Preparation method of PCL / Fe composite vascular stent, the steps are as follows:

[0040] Use PCL wire and print through an FDM printer with the following parameters: nozzle diameter 0.2 mm, filling rate 100%, nozzle temperature 130 °C, substrate temperature 45 °C, layer thickness 0.1 mm and printing speed 100 mm / s, and print sinusoidal thin sheets with a thickness of 0.1 mm and / or 0.2 mm respectively;

[0041] Bend a wire with a diameter of 0.2 mm into a sine shape that conforms to the design, and lay it on a 0.2 mm thick PCL sheet. Place this sheet on a heating plate at 60 °C for heating. Cover the wire with a 0.1 mm thick PCL sheet and gently press to bond the two PCL sheets together while wrapping the wire structure. After cooling, remove it to obtain a PCL / Fe sheet;

[0042] Bend the PCL / Fe sheet along the short side into a tubular structure. Bring the two ends of the wire together and tie a knot to fix it, and wrap the wire knot with molten PCL material to ensure that the wire is completely enclosed, obtaining a PCL / Fe composite vascular stent.

[0043] Example 2 Preparation method of PCL / Zn composite vascular stent, the steps are as follows:

[0044] Use PCL wire and print through an FDM printer with the following parameters: nozzle diameter 0.2 mm, filling rate 100%, nozzle temperature 130 °C, substrate temperature 45 °C, layer thickness 0.1 mm, and printing speed 100 mm / s, respectively print sine-shaped sheets with a thickness of 0.1 mm and / or 0.2 mm;

[0045] Bend a zinc wire with a diameter of 0.2 mm into a sine shape that conforms to the design, and lay it on a 0.2 mm thick PCL sheet. Place this sheet on a heating plate at 60 °C for heating. Cover the zinc wire with a 0.1 mm thick PCL sheet and gently press to bond the two PCL sheets together while wrapping the zinc wire structure. After cooling, remove it to obtain a PCL / Zn sheet;

[0046] Bend the PCL / Zn sheet along the short side into a tubular structure. Bring the two ends of the zinc wire together and tie a knot to fix it, and wrap the zinc wire knot with molten PCL material to ensure that the zinc wire is completely enclosed and avoid exposure, obtaining a PCL / Zn composite vascular stent.

[0047] Example 3 Preparation method of PPDO / Fe composite vascular stent, the steps are as follows:

[0048] Use PPDO wire and print through an FDM printer with the following parameters: nozzle diameter 0.2 mm, filling rate 100%, nozzle temperature 180 °C, substrate temperature 80 °C, layer thickness 0.1 mm, and printing speed 100 mm / s, respectively print sine-shaped sheets with a thickness of 0.1 mm and / or 0.2 mm;

[0049] Bend a wire with a diameter of 0.2 mm into a sine shape that conforms to the design, and lay it on a 0.2-mm-thick PPDO thin sheet. Place this thin sheet on a heating plate at 90 °C for heating. Cover the wire with a 0.1-mm-thick PPDO thin sheet, and gently press to bond the two PPDO thin sheets together while wrapping the wire structure. After cooling, remove it to obtain a PPDO / Fe sheet;

[0050] Bend the PPDO / Fe sheet along the short side into a tubular structure. Bring the two ends of the wire together and tie a knot to fix it, and wrap the knot of the wire with molten PPDO material to ensure that the wire is completely enclosed, obtaining a PPDO / Fe composite vascular stent.

[0051] Example 4 Preparation method of PPDO / Zn composite vascular stent, the steps are as follows:

[0052] Use PPDO wire and print it with an FDM printer using the following parameters: nozzle diameter 0.2 mm, filling rate 100%, nozzle temperature 180 °C, substrate temperature 80 °C, layer thickness 0.1 mm, and printing speed 100 mm / s, respectively print sine-shaped thin sheets with a thickness of 0.1 mm and / or 0.2 mm;

[0053] Bend a zinc wire with a diameter of 0.2 mm into a sine shape that conforms to the design, and lay it on a 0.2-mm-thick PPDO thin sheet. Place this thin sheet on a heating plate at 90 °C for heating. Cover the zinc wire with a 0.1-mm-thick PPDO thin sheet, and gently press to bond the two PPDO thin sheets together while wrapping the zinc wire structure. After cooling, remove it to obtain a PPDO / Zn sheet;

[0054] Bend the PPDO / Zn sheet along the short side into a tubular structure. Bring the two ends of the zinc wire together and tie a knot to fix it, and wrap the knot of the zinc wire with molten PPDO material to ensure that the zinc wire is completely enclosed, obtaining a PPDO / Zn composite vascular stent.

[0055] Test Example 1 Detection of the radial support force of the stent

[0056] Measure the radial support force of the stents in Examples 1-4 and the commercially available Genesis stent. The results are shown in Table 1:

[0057]

[0058] As can be seen from Table 1, the PPDO / Fe stent has the highest radial support force, and the radial support forces of the other stents are also significantly better than those of the Genesis commercial permanent metal stent (diameter 6 mm, stainless steel, hollow grid-shaped tubular stent), which can meet the requirements of clinical use for the radial strength of the stent.

[0059] The above-described embodiments merely represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all fall within the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. A method for preparing a composite vascular stent, characterized in that, It includes the following steps: S1. Design of a sinusoidal stent; S2. Preparation of a sinusoidal polymer thin sheet by fused deposition modeling (FDM); S3. Lay a metal wire on the polymer thin sheet, cover it with another polymer thin sheet after heating, and perform hot pressing to bond the two polymer thin sheets together to obtain a polymer / metal sheet; S4. Bend the polymer / metal sheet along the short side into a tubular structure, bring the iron wires at both ends together and tie them firmly, and wrap the iron wire knot with molten polymer material to ensure that the iron wire is completely enclosed and avoid exposure, thereby obtaining a composite vascular stent.

2. The preparation method of the composite vascular stent according to claim 1, characterized in that, The polymer thin sheet is a PCL polymer thin sheet or a PPDO polymer thin sheet.

3. The preparation method of the composite vascular stent according to claim 2, characterized in that, When the polymer thin sheet is a PCL polymer thin sheet, the FDM parameters are set as follows: nozzle diameter 0.2 mm, filling rate 100%, nozzle temperature 90°C - 140°C, substrate temperature 30°C - 45°C, printing speed 100 mm / s.

4. The preparation method of the composite vascular stent according to claim 2, characterized in that, When the polymer thin sheet is a PPDO polymer thin sheet, the FDM parameters are set as follows: nozzle diameter 0.2 mm, filling rate 100%, nozzle temperature 150°C - 190°C, substrate temperature 70°C - 90°C, layer thickness 0.1 mm, printing speed 100 mm / s.

5. The preparation method of the composite vascular stent according to claim 1, characterized in that, The thickness of the polymer thin sheet is 0.1 - 0.2 mm.

6. The preparation method of the composite vascular stent according to claim 1, wherein, The metal wire is an iron wire or a zinc wire, and the metal wire is sinusoidal and conforms to the design.

7. The preparation method of the composite vascular stent according to claim 1, wherein, The diameter of the metal wire is 0.2 mm.

8. The preparation method of the composite vascular stent according to claim 1, characterized in that, The hot pressing temperature is 55°C - 65°C or 90°C - 100°C.

9. The preparation method of the composite vascular stent according to claim 1, characterized in that, The polymer material is PCL or PPDO.

10. A composite vascular stent, characterized in that, Prepared by the method according to any one of claims 1 - 9.

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