A method for preparing a degradable vascular stent

Abstract

This invention discloses a method for preparing a biodegradable vascular stent, which overcomes the defects in the preparation process of vascular stents in the prior art. By setting a large-area sheet drop structure and introducing a redesigned sheet drop line, the problem of sheet drop difficulty is overcome. In addition, the prior art inevitably has the problem of multiple cuts in the same area. Since the laser itself has extremely high heat, passing through the same area will cause local burns. The vascular stent itself will be in direct contact with the blood vessel wall. This defect on the surface of the vascular stent may scratch the blood vessel during the expansion process, causing additional damage. Therefore, this application uses the boundary line between the sheet drop and the stent as the cutting path and additionally sets the entry point to avoid the burn problem caused by repeated local cutting.

Description

Technical Field

[0001] This application belongs to the field of medical devices, specifically relating to a method for preparing a biodegradable vascular stent. Background Technology

[0002] Vascular stents are medical devices that, based on balloon dilation and shaping of the lumen, are inserted into the diseased segment of the blood vessel to support the narrowed or occluded segment, reduce elastic recoil and remodeling, and maintain unobstructed blood flow. They are currently the primary technology for treating vascular occlusion. Due to the small radius and complex structure of blood vessels, the processing and production of vascular stents present challenges. Current technologies primarily utilize laser cutting for processing, and laser engraving can achieve micron-level dimensions, meeting the processing requirements of vascular stents.

[0003] However, in actual use, it has been found that the laser has a large energy, and the usual cutting is carried out along the outer contour of the vascular stent. The cut part is a closed shape, and it is inevitable that there will be multiple cuts in the same area. The laser itself has extremely high heat, and passing through the same area will cause local burns. The vascular stent itself will be in direct contact with the blood vessel wall. This defect on the surface of the vascular stent may scratch the blood vessel during the opening process, causing additional damage. In addition, the difficulty of material cutting is more common due to the different materials used. Summary of the Invention

[0004] The purpose of this application is to provide a method for preparing a biodegradable vascular stent, especially a zinc-based alloy stent. By introducing and redesigning the blanking line, the problem of blanking difficulty is overcome, and the cutting path is further optimized to avoid the burn-out problem caused by local repeated cutting when cutting closed patterns.

[0005] To achieve the above objectives, this application adopts the following technical solution.

[0006] A method for preparing a biodegradable vascular stent includes the following steps: S1: Structural design of vascular stents; S2: Laser cutting and shaping: The edge shape of the vascular stent is used as the cutting path. The laser moves along the cutting path on the tube. As the laser moves, the vascular stent separates from the tube. S3: Ultrasonic material removal: The cut stent is placed in a beaker, which is then placed in an ultrasonic cleaning tank with a fixed frequency to remove the part of the vascular stent from the tube, thus completing the material removal. S4: Post-processing; Post-processing of the blanked stent, including one or more of the following processes: polishing, initial washing, final cleaning, polymer / drug spraying, pressing, packaging, and sterilization. In S1, a drop sheet is also designed, which overlaps with the edge of the vascular stent. The overlapping edge of the two is the laser cutting path, and the drop sheet is provided with a drop line to assist in the detachment.

[0007] Furthermore, the edge of the film is a non-closed curve, with a gap between the start and end points.

[0008] Furthermore, the edge of the falling sheet is provided with an inlet as the starting point of the cutting path. The cutting path extends outward from the starting point to the edge of the falling sheet and moves along the edge of the falling sheet. The end point of the cutting path is close to the inlet.

[0009] Furthermore, there are multiple blanking lines, which can be one or more combinations of straight lines, broken lines, and curves.

[0010] Furthermore, the blanking line does not contact the edge of the blank, and the distance between the two is 10-20 micrometers.

[0011] This application has at least the following beneficial effects: By setting a drop structure, the forming effect of cutting vascular stents is optimized. The drop structure is the same as the edge of the vascular stent, making it easier to detach. Moreover, the drop structure is a non-closed shape, which effectively avoids the defects caused by repeated cutting at the same position. In addition, an entry point is set on the cutting path as the starting point of laser cutting, and a drop line is also set on the drop piece. The drop line is set or extends to the body and tip of the drop piece, which overcomes the problem of difficulty in detaching large-volume and complex-shaped drop pieces. Attached Figure Description

[0012] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0013] Figure 1 A schematic diagram of the vascular stent structure in this application is shown. Figure 2 The processing drawings of this application are shown schematically; Figure 3 A schematic diagram of the sheet structure is shown. Figure 4 A schematic diagram of the physical object in Experimental Example 1 is shown. Figure 5 A schematic diagram of the physical object of Embodiment 2 is shown; Figure 6 A schematic diagram of the physical object of Embodiment 3 is shown.

[0014] Wherein: 1-bracket, 2-drop plate, 21-drop line a, 22-drop line b, 3-cutting path, 31-entry point. Detailed Implementation

[0015] To provide a clearer understanding of the technical features, objectives, and effects of this invention, specific embodiments are now described in detail with reference to the accompanying drawings. In the following description, it should be understood that the orientations or positional relationships indicated by terms such as "front," "rear," "upper," "lower," "left," "right," "longitudinal," "horizontal," "vertical," "horizontal," "top," "bottom," "inner," "outer," "head," and "tail" are based on the orientations or positional relationships shown in the accompanying drawings, and are constructed and operated in a specific orientation. They are only for the convenience of describing this technical solution and do not indicate that the device or element referred to must have a specific orientation; therefore, they should not be construed as limitations on this invention.

[0016] It should also be noted that, unless otherwise explicitly specified and limited, terms such as "installation," "connection," "linking," "fixing," and "setting" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. When an component is referred to as being "on" or "below" another component, the component can be located "directly" or "indirectly" on the other component, or there may be one or more intermediary components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0017] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, so as to provide a thorough understanding of the embodiments of the invention; however, those skilled in the art will understand that the invention may be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, and methods are omitted so as not to obscure the description of the invention with unnecessary detail. Example

[0018] The figure shows a method for fabricating a biodegradable vascular stent, which is etched onto a metal tube using a laser. The specific steps are as follows: S1: Structural design of the vascular stent; complete the morphological design of vascular stent 1 and the structural design of the sheet 2. The structure of the vascular stent is as follows: Figure 1 As shown, the structure of the droplet 2 is laid on the tube in close connection with the vascular stent 1.

[0019] S2: Laser cutting forming: The processing drawings are imported into the laser cutting machine, the tube is fixed to the rotating platform therein by the clamp, and the position of the laser nozzle is adjusted so that the laser moves along the predetermined cutting path 3. In this application, the laser cutting path 3 basically coincides with the boundary line between the vascular stent 1 and the sheet 2. As the laser moves, the sheet 2 and the vascular stent 1 are initially separated. It should be noted that the initial separation is not a complete detachment, but rather the separation of the vascular stent 1 and the fragment 2 from the tube. The two are relatively separated, but there is still some adhesion in the local area, so they do not necessarily detach directly.

[0020] S3: Ultrasonic material removal: The cut stent 1 is placed in a beaker, which is then placed in a fixed-frequency ultrasonic cleaning tank containing purified water. Under the action of ultrasound, the sheet 2 breaks off from the remaining part of the vascular stent 1, completing the final separation of the two.

[0021] It should be noted that the larger area of ​​the detached piece 2 increases the overall tendency of the detached piece 2 to fall off. Under the action of ultrasonic vibration, it eventually separates from the vascular stent 1, avoiding the residue of small local areas, and separates from the tube along with the detached piece 2.

[0022] S4: Post-process the obtained vascular stent 1, including but not limited to: sandblasting, acid washing, and sterilization.

[0023] In S2, the laser cutting path 3 is a closed shape formed by the edge of the vascular stent 1. This application also additionally provides an inlet 31, which is a smooth path, one end of which is located within the drop piece 2, and the other end connects to the existing cutting path 3 to form a new laser cutting path 3; as shown... Figure 3 As shown, the end point of the new cutting path 3 is not connected to the inlet 31, but close to the connection point between the inlet 31 and the original cutting path 3. The gap between the two is less than 1 mm, which avoids local burn-out caused by the overlap of the laser cutting paths 3. However, the drop piece 2 is not a closed shape, which also brings the inherent defect of difficulty in dropping the material.

[0024] Furthermore, S1 also includes a drop piece 2, which creatively divides the tubular part into a vascular stent 1, a drop piece 2, and a small amount of residual structural combination. By constructing a larger volume drop piece 2, the complexly curved vascular stent 1 can be effectively separated from the tubular part, avoiding the processing defects of the vascular stent 1.

[0025] Specifically: the edge of the sheet 2 contacts the edge of the vascular stent 1, greatly reducing the area of ​​excess material, especially in corners where it is difficult to detach. The excess material at the inlet 31 of the cutting path 3 connects the sheet 2 and the vascular stent 1, making it easier to detach and less prone to defects.

[0026] A blanking line is also provided at the blanking plate 2 position. The blanking line is a slot set on the blanking plate 2, and no part of the blanking line is connected to the edge of the blanking plate 2. The closest part between the two has a gap of at least 10-20 micrometers. The blanking line increases the tendency of the blanking plate 2 to fall off, rather than being used directly to divide the blanking plate 2.

[0027] Furthermore, the blanking line a 21 is located in the middle part of the blanking sheet. The blanking line a 21 is a series of broken lines extending from one end to the other along the length of the blanking sheet, dividing the blanking sheet into two parts with equal areas. The blanking line b 22 is located in the protruding angular parts on the outer side of the blanking sheet. The blanking line b 22 is a series of intersecting lines.

[0028] In another preferred embodiment, the blanking line a 21 is a curve, preferably a sine curve.

[0029] In another preferred embodiment, the blanking line b 22 is a combination of curves and straight lines.

[0030] Experimental Example Experimental materials: 3 zinc alloy pipes; Experimental equipment: laser cutter, ultrasonic cleaner, purified water, alcohol; Experimental Example 1 S1: Structural design of vascular stent 1; completion of morphological design of vascular stent 1.

[0031] S2: Laser cutting and shaping: Plan the laser cutting path 3, which is a closed path formed by the external shape of the vascular stent 1. The starting point and the ending point are the same. Fix the tube to the rotating platform with a clamp and adjust the position of the laser nozzle. The laser operates along the predetermined cutting path 3 by the movement of the rotating platform.

[0032] S3: Ultrasonic material removal: The cut stent 1 is placed in a beaker, which is then placed in a fixed-frequency ultrasonic cleaning tank containing purified water, and the vascular stent 1 is detached from the tubing.

[0033] S4: Chemically polish the obtained vascular stent 1.

[0034] Experiment Example 2 S1: Structural design of vascular stent: The morphological design of the vascular stent and the design of the sheet-dropping structure are completed. The sheet-dropping structure is laid on the tube in close connection with the vascular stent. The sheet-dropping structure is also provided with a material drop line, as described in the embodiment.

[0035] S2: Laser cutting and shaping: Plan the laser cutting path 3. This path is basically coincident with but not closed to the boundary line between the laser cutting path 3 and the vascular stent 1 and the sheet 2. An additional inlet 31 is set on the cutting path 3. The inlet 31 is located inside the sheet 2 and extends smoothly to the boundary line between the vascular stent 1 and the sheet 2. The starting point of the cutting path 3 is not connected to the inlet 31 and is a non-closed curve.

[0036] The pipe is fixed to the rotating platform by a clamp, and the laser operates along the predetermined cutting path by the movement of the rotating platform.

[0037] S3: Ultrasonic material removal: The cut stent is placed in a beaker, which is then placed in a fixed-frequency ultrasonic cleaning tank containing purified water, and the vascular stent is detached from the tubing.

[0038] S4: Chemically polish the obtained vascular stent.

[0039] like Figure 4-5 As shown, the method of adding a drop sheet 2 structure and setting a drop line on the drop sheet 2 results in a better drop sheet effect, with no extra material remaining on the vascular stent 1. Additional, such as Figures 4-5 As shown, a closed path will inevitably have locations where repeated cutting occurs. Laser cutting also utilizes high-energy lasers to partially melt metal, and these repeated cuts will result in varying degrees of burn-off defects. Figure 4 The defect circled in section A is difficult to eliminate through chemical treatment. For products that come into direct contact with blood vessel walls, it may cause serious problems such as blood vessel damage.

[0040] like Figure 5 As shown in the figure, Example 2 avoids the occurrence of ablation defects by constructing a non-closed cutting path 3. However, it can be seen from the figure that there are still some defects in the product. Therefore, based on Example 2, Experiment 3 is set up for comparison.

[0041] Experimental Example 3 S1: Structural design of vascular stent: Complete the morphological design of vascular stent and the design of the strip structure. The strip is laid on the tube in close connection with the vascular stent; the strip is also equipped with a material dropping line.

[0042] Preferably, the distance between the blanking line and the edge of the blanking sheet is set to 10-20 micrometers.

[0043] S2: Laser cutting and shaping: Plan the laser cutting path 3. This path is basically coincident with but not closed to the boundary line between the laser cutting path 3 and the vascular stent 1 and the sheet 2. An additional inlet 31 is set on the cutting path 3. The inlet 31 is located inside the sheet 2 and extends smoothly to the boundary line between the vascular stent 1 and the sheet 2. The starting point of the cutting path 3 is not connected to the inlet 31 and is a non-closed curve.

[0044] The pipe is fixed to the rotating platform by a clamp, and the position of the laser nozzle is adjusted so that the laser moves along the predetermined cutting path 3.

[0045] S3: Ultrasonic material removal: The cut stent 1 is placed in a beaker, which is then placed in a fixed-frequency ultrasonic cleaning tank containing purified water, and the vascular stent 1 is detached from the tubing.

[0046] S4: Chemically polish the obtained vascular stent 1.

[0047] contrast Figures 5-6 It is known that although the blanking line can facilitate the detachment of the blank 2, the blanking line is also formed by laser processing, and the relative position of the blanking line and the blank 2 may also cause new processing defects; therefore, in this embodiment, a distance parameter between the blanking line and the edge of the blank 2 is set, and through... Figure 6 It can be seen that, under specific distance parameters, defects caused by laser during blanking line forming can be avoided, resulting in a smoother surface and improved implantation safety.

Claims

1. A method for preparing a biodegradable vascular stent, comprising the following steps: S1: Structural design of vascular stents; S2: Laser cutting and shaping: The edge shape of the vascular stent is used as the cutting path. The laser moves along the cutting path on the tube. As the laser moves, the vascular stent separates from the tube. S3: Ultrasonic material removal: The cut stent is placed in a beaker, which is then placed in an ultrasonic cleaning tank with a fixed frequency to remove the part of the vascular stent from the tube, thus completing the material removal. S4: post-processing; the support after blanking is post-processed, and the post-processing process includes: One or more of the following processes and combinations: polishing, initial washing, final cleaning, polymer / drug spraying, pressing, packaging, and sterilization; The feature is that: in S1, a drop sheet is also designed, the drop sheet coincides with the edge of the vascular stent, the overlapping edge of the two is the laser cutting path, and the drop sheet is provided with a drop line to assist in the detachment.

2. The method for preparing a biodegradable vascular stent according to claim 2, characterized in that: The edge of the dropped piece is a non-closed curve, with a gap between the start and end points.

3. The method for preparing a biodegradable vascular stent according to claim 2, characterized in that: The edge of the falling piece is provided with an inlet as the starting point of the cutting path. The cutting path extends outward from the starting point to the edge of the falling piece and moves along the edge of the falling piece. The end point of the cutting path is close to the inlet.

4. The method for preparing a biodegradable vascular stent according to claim 1, characterized in that: The blanking line is a slot on the blanking sheet. There are multiple blanking lines, which can be one or more combinations of straight lines, broken lines, and curves.

5. The method for preparing a biodegradable vascular stent according to claim 1, characterized in that: The blanking line does not contact the edge of the blank, and the distance between the two is 10-20 micrometers.

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