阅读说明：本技术 可降解复合金属编织支架及其制备方法 (Degradable composite metal woven stent and preparation method thereof ) 是由 白晶 程兆俊 邵怡 于 2020-12-30 设计创作，主要内容包括：本发明提供一种可降解复合金属编织支架及其制备方法,属于医疗器械技术领域。制备方法包括：对镁合金铸锭和锌合金铸锭分别进行加工,以形成相应的镁合金棒材以及一端封闭的锌合金管材,并将镁合金棒材置于锌合金管材中形成压合铸锭；对压合铸锭进行热挤压处理,以形成复合金属棒材；对复合金属棒材经过拉拔处理和退火处理,以形成复合金属丝材；对复合金属丝材进行编织,以获得可降解复合金属编织支架。本发明通过铸锭嵌套复合制备,无膜层的额外制备工序。本发明得到的可降解复合金属编织支架具有内外层复合结构,外层的锌合金降解速度缓慢,获得足够服役时间,同时芯部的镁合金在外层锌合金的保护下,植入后降解过程中可提供有效的力学性能。(The invention provides a degradable composite metal braided stent and a preparation method thereof, belonging to the technical field of medical instruments. The preparation method comprises the following steps: respectively processing a magnesium alloy ingot and a zinc alloy ingot to form a corresponding magnesium alloy rod and a zinc alloy pipe with one closed end, and placing the magnesium alloy rod in the zinc alloy pipe to form a pressed ingot; carrying out hot extrusion treatment on the pressed cast ingot to form a composite metal bar; drawing and annealing the composite metal bar to form a composite metal wire; weaving the composite metal wire to obtain the degradable composite metal woven stent. The invention is prepared by ingot casting nesting and compounding without additional preparation process of a film layer. The degradable composite metal braided stent obtained by the invention has an inner-layer and outer-layer composite structure, the degradation speed of the zinc alloy of the outer layer is slow, enough service time is obtained, and meanwhile, the magnesium alloy of the core part can provide effective mechanical property in the degradation process after being implanted under the protection of the zinc alloy of the outer layer.)

1. A preparation method of a degradable composite metal woven stent is characterized by comprising the following steps: respectively processing a magnesium alloy ingot and a zinc alloy ingot to form a corresponding magnesium alloy rod and a zinc alloy pipe with one closed end, and placing the magnesium alloy rod in the zinc alloy pipe to form a pressed ingot;

carrying out hot extrusion treatment on the pressed cast ingot to form a composite metal bar;

drawing and annealing the composite metal bar to form a composite metal wire;

and weaving the composite metal wire to obtain the degradable composite metal woven stent.

2. The method of claim 1, wherein the placing the magnesium alloy rod into the zinc alloy tube to form a pressed ingot comprises:

and (3) placing the magnesium alloy rod in the zinc alloy pipe, placing the zinc alloy pipe in a pressing die with the temperature range of 250-350 ℃, and uniformly treating for 1-3 h under the pressure range of 80-120 MPa to form a pressed ingot.

3. The method of claim 1, wherein the hot extrusion of the bonded ingot to form a composite metal bar comprises:

and carrying out single-hole hot extrusion on the pressed cast ingot at the extrusion temperature range of 200-250 ℃ and the extrusion speed range of 1-3 mm/s to form a composite metal bar with the diameter range of 2-4 mm.

4. The method of claim 1, wherein the subjecting the composite metal rod to a drawing process and an annealing process to form a composite metal wire comprises:

and carrying out drawing treatment on the composite metal bar for many times, and annealing treatment at the annealing temperature range of 150-300 ℃ to obtain the composite metal wire with the diameter range of 0.1-0.3 mm.

5. The method of claim 1, wherein said braiding said composite metal wire to obtain said degradable composite metal braided stent comprises:

and weaving the composite metal wire by adopting a diamond structure as a weaving structure to obtain the degradable composite metal woven stent with a first mesh internal angle and a second mesh internal angle.

6. The method of claim 5, wherein the first mesh interior angle ranges from 40 ° to 50 °; and/or the presence of a gas in the gas,

the internal angle range of the second meshes is 130-140 degrees.

7. The method according to any one of claims 1 to 6, wherein the magnesium alloy ingot is made of magnesium-zinc alloy or magnesium-zinc-calcium alloy; and/or the presence of a gas in the gas,

the zinc alloy ingot adopts any one of zinc-copper alloy, zinc-lithium-manganese alloy and zinc-lithium-copper alloy.

8. The method of claim 7, wherein the composition of the magnesium-zinc alloy comprises 1 to 5 wt% Zn, with the balance being Mg; and/or the presence of a gas in the gas,

the magnesium-zinc-calcium alloy comprises 1-3 wt% of Zn, 0.1-1 wt% of Ca and the balance of Mg; and/or the presence of a gas in the gas,

the zinc-copper alloy comprises 0.1-1 wt% of Cu and the balance of Zn; and/or the presence of a gas in the gas,

the components of the zinc-lithium alloy comprise 0.1-1 wt% of Li and the balance of Zn; and/or the presence of a gas in the gas,

the components of the zinc-lithium-manganese alloy comprise 0.1-1 wt% of Li, 0.1-0.5 wt% of Mn and the balance of Zn; and/or the presence of a gas in the gas,

the components of the zinc-lithium-copper alloy comprise 0.1-1 wt% of Li, 0.1-0.5 wt% of Cu and the balance of Zn.

9. The method according to any one of claims 1 to 6, wherein the magnesium alloy rod has a diameter 2 to 4 times the wall thickness of the zinc alloy pipe, and the diameter of the magnesium alloy rod is 0.01 to 0.03mm smaller than the inner diameter of the zinc alloy pipe.

10. A degradable composite metal woven stent, characterized in that it is prepared by the method of any one of claims 1 to 9.

Technical Field

The invention belongs to the technical field of medical appliances, and particularly relates to a degradable composite metal woven stent and a preparation method of the degradable composite metal woven stent.

Background

There are many lumens in the human body, such as blood vessels, biliary tract, intestinal tract, urethra, etc., which mainly serve to transport substances. When vascular embolism, prostatic hyperplasia and other lumen stenosis and obstructive diseases occur, the functional operation of the human body and even the life safety are damaged, and the occurrence rate and the danger of the middle-aged and elderly people are high.

The stent is a common medical instrument, has various shapes and sizes, and is usually used for supporting the lumen wall clinically at present in a stent intervention mode to play a role in expanding the lumen tract of a diseased region. However, most of the existing stents are non-degradable stents made of materials such as nickel titanium, stainless steel and the like, most of the existing stents cannot be taken out after being implanted into a human body and can only be kept for a long time, which can cause endothelial cell hyperplasia to cause restenosis. In order to solve the problem of permanent retention, various degradable stent technologies have been disclosed in recent years. In the prior art, the degradable stents are mainly classified into two types, polymer-based stents and metal-based stents. For example: one of the prior art, chinese patent CN101972181B discloses a bioabsorbable stent, which uses high molecules such as polylactic acid, polycaprolactone, polyglycolic acid, etc. as the matrix, has good degradability, biocompatibility and drug-loading function, and is more suitable for children blood vessels. One of the prior art, chinese patent application CN102908216A, discloses a bioabsorbable medical human body lumen stent, the used wire material uses magnesium alloy material as the substrate, and is covered with biodegradable ceramic layer and polymer layer, which has slower degradation rate and excellent mechanical property. One of the prior art, chinese patent application CN102727331A, discloses a biodegradable magnesium alloy bile duct litholytic braided stent, which uses a magnesium alloy wire as a stent matrix, and has good mechanical properties and therapeutic effects for biliary tract calculus with litholytic drugs loaded on the surface.

However, the problems of the degradable polymer scaffold and the degradable metal scaffold still remain to be solved and improved. The degradable polymer scaffold is generally poor in mechanical property, weak in supporting effect on the tube wall and lack of biological activity. At present, the degradable metal stent mainly takes magnesium alloy wires as a base material, the mechanical property is good, but the degradation rate of the magnesium alloy is too high, a film layer is usually used as a protective layer, the preparation process is complex, and once the protective layer is damaged, the degradation rate of the magnesium alloy is accelerated, and higher storage conditions are needed.

Therefore, in view of the above technical problems, there is a need for a new degradable composite metal woven stent and a preparation method thereof, which has excellent mechanical properties and slow degradation rate.

Disclosure of Invention

The invention aims to at least solve one of the technical problems in the prior art and provides a degradable composite metal woven stent and a preparation method of the degradable composite metal woven stent.

In one aspect of the present invention, a method for preparing a degradable composite metal woven stent is provided, which comprises: respectively processing a magnesium alloy ingot and a zinc alloy ingot to form a corresponding magnesium alloy rod and a zinc alloy pipe with one closed end, and placing the magnesium alloy rod in the zinc alloy pipe to form a pressed ingot;

carrying out hot extrusion treatment on the pressed cast ingot to form a composite metal bar;

drawing and annealing the composite metal bar to form a composite metal wire;

and weaving the composite metal wire to obtain the degradable composite metal woven stent.

Optionally, the step of placing the magnesium alloy rod in the zinc alloy pipe to form a pressed ingot comprises:

and (3) placing the magnesium alloy rod in the zinc alloy pipe, placing the zinc alloy pipe in a pressing die with the temperature range of 250-350 ℃, and uniformly treating for 1-3 h under the pressure range of 80-120 MPa to form a pressed ingot.

Optionally, the performing a hot extrusion process on the pressed ingot to form a composite metal bar includes:

and carrying out single-hole hot extrusion on the pressed cast ingot at the extrusion temperature range of 200-250 ℃ and the extrusion speed range of 1-3 mm/s to form a composite metal bar with the diameter range of 2-4 mm.

Optionally, the drawing and annealing processes are performed on the composite metal bar to form a composite metal wire, and the method includes:

and carrying out drawing treatment on the composite metal bar for many times, and annealing treatment at the annealing temperature range of 150-300 ℃ to obtain the composite metal wire with the diameter range of 0.1-0.3 mm.

Optionally, the weaving the composite metal wire to obtain the degradable composite metal woven stent includes:

and weaving the composite metal wire by adopting a diamond structure as a weaving structure to obtain the degradable composite metal woven stent with a first mesh internal angle and a second mesh internal angle.

Optionally, the internal angle range of the first meshes is 40-50 degrees; and/or the presence of a gas in the gas,

the internal angle range of the second meshes is 130-140 degrees.

Optionally, the magnesium alloy ingot is magnesium-zinc alloy or magnesium-zinc-calcium alloy; and/or the presence of a gas in the gas,

the zinc alloy ingot adopts any one of zinc-copper alloy, zinc-lithium-manganese alloy and zinc-lithium-copper alloy.

Optionally, the magnesium-zinc alloy comprises 1 wt% -5 wt% of Zn, and the balance of Mg; and/or the presence of a gas in the gas,

the magnesium-zinc-calcium alloy comprises 1-3 wt% of Zn, 0.1-1 wt% of Ca and the balance of Mg; and/or the presence of a gas in the gas,

the zinc-copper alloy comprises 0.1-1 wt% of Cu and the balance of Zn; and/or the presence of a gas in the gas,

the components of the zinc-lithium alloy comprise 0.1-1 wt% of Li and the balance of Zn; and/or the presence of a gas in the gas,

the components of the zinc-lithium-manganese alloy comprise 0.1-1 wt% of Li, 0.1-0.5 wt% of Mn and the balance of Zn; and/or the presence of a gas in the gas,

the components of the zinc-lithium-copper alloy comprise 0.1-1 wt% of Li, 0.1-0.5 wt% of Cu and the balance of Zn.

Optionally, the diameter of the magnesium alloy rod is 2-4 times of the wall thickness of the zinc alloy pipe, and the diameter of the magnesium alloy rod is 0.01-0.03 mm smaller than the inner diameter of the zinc alloy pipe.

In another aspect of the present invention, a degradable composite metal woven stent is provided, which is prepared by the above-mentioned method for preparing a degradable composite metal woven stent.

The invention provides a preparation method of a degradable composite metal woven stent, which comprises the following steps: respectively processing a magnesium alloy ingot and a zinc alloy ingot to form a corresponding magnesium alloy rod and a zinc alloy pipe with one closed end, and placing the magnesium alloy rod in the zinc alloy pipe to form a pressed ingot; carrying out hot extrusion treatment on the pressed cast ingot to form a composite metal bar; drawing and annealing the composite metal bar to form a composite metal wire; and weaving the composite metal wire to obtain the degradable composite metal woven stent. The preparation method disclosed by the invention is prepared by ingot casting nesting and compounding, no additional preparation process of a film layer is required, the preparation is simple, the outer layer is made of zinc alloy, and the requirement on storage conditions is lower. The degradable composite metal braided stent obtained by the preparation method has an inner-layer and outer-layer composite structure, the degradation speed of the zinc alloy of the outer layer is slow, enough service time can be obtained, and meanwhile, the magnesium alloy of the core part can still provide effective mechanical properties in the degradation process after implantation under the protection of the zinc alloy of the outer layer.

Drawings

Fig. 1 is a flow chart of a method for manufacturing a degradable composite metal woven stent according to an embodiment of the invention;

FIG. 2 is a schematic diagram of a magnesium alloy rod and a zinc alloy pipe with one end closed to form a pressed ingot according to another embodiment of the invention;

FIG. 3 is a schematic cross-sectional view of another embodiment of a composite metal wire of the present invention;

FIG. 4 is a schematic diagram of a diamond structure used in weaving according to another embodiment of the present invention;

fig. 5 is a schematic structural diagram of a degradable composite metal woven stent according to another embodiment of the invention.

Detailed Description

In order to make the technical solutions of the present invention better understood, the present invention will be described in further detail with reference to the accompanying drawings and specific embodiments. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the described embodiments of the invention without any inventive step, are within the scope of protection of the invention.

As shown in fig. 1, in one aspect of the present invention, a method S100 for preparing a degradable composite metal woven stent is provided, which specifically includes the following steps S110 to S140:

s110, respectively processing the magnesium alloy ingot and the zinc alloy ingot to form a corresponding magnesium alloy rod and a zinc alloy pipe with one closed end, and placing the magnesium alloy rod in the zinc alloy pipe to form a pressed ingot.

Specifically, a magnesium alloy ingot and a zinc alloy ingot are selected, a magnesium alloy rod (such as 110 in fig. 2) and a zinc alloy pipe (such as 120 in fig. 2) with one end sealed are obtained through a machining mode, then the magnesium alloy rod is placed in the zinc alloy pipe, the zinc alloy pipe is integrally placed in a pressing die with the temperature range of 250-350 ℃, and the pressing ingot (such as 130 in fig. 2) is formed through uniform treatment for 1-3 h under the pressure range of 80-120 MPa.

In some embodiments, the whole of the magnesium alloy rod and the zinc alloy pipe can be put into a pressing die at 300 ℃ and subjected to homogenization treatment for 2 hours under the pressure of 100MPa to obtain a pressed ingot.

It should be noted that, through many experiments, the inventor of the present invention finds that a stent using a zinc alloy wire as a base material has a slow degradation rate, good plasticity and a weak support property, and thus, in this embodiment, the zinc alloy wire is matched with a magnesium alloy having a good mechanical property to obtain a stent having an outer layer made of a zinc alloy and an inner core made of a magnesium alloy, so that the stent has a good mechanical property and a slow degradation rate, and solves the problems of a weak support force of the current stent, a too fast degradation rate of the magnesium alloy, and the like.

It should be further noted that the magnesium alloy ingot of the present embodiment may use magnesium-zinc alloy or magnesium-zinc-calcium alloy, and the zinc alloy ingot may use any one of zinc-copper alloy, zinc-lithium-manganese alloy, and zinc-lithium-copper alloy, which is not particularly limited.

It should be noted that, in some embodiments, when the magnesium alloy ingot is made of magnesium-zinc alloy, the composition of the magnesium alloy ingot includes 1 wt% to 5 wt% of Zn, and the balance is Mg. In other embodiments, when the magnesium-zinc-calcium alloy is selected as the magnesium alloy ingot, the magnesium alloy ingot comprises 1 wt% to 3 wt% of Zn, 0.1 wt% to 1 wt% of Ca, and the balance of Mg. Of course, in some embodiments, the zinc alloy ingot may be selected from a zinc-copper alloy having a composition including 0.1 wt% to 1 wt% Cu, with the balance being Zn. In other embodiments, the zinc alloy ingot may be selected from a zinc-lithium alloy having a composition including 0.1 wt% to 1 wt% Li, with the balance being Zn. In other embodiments, the zinc alloy ingot can also be selected from a zinc-lithium-manganese alloy, and the composition of the zinc alloy ingot comprises 0.1 wt% to 1 wt% of Li, 0.1 wt% to 0.5 wt% of Mn, and the balance of Zn. In other embodiments, the zinc alloy ingot can also be a zinc-lithium-copper alloy, which comprises 0.1 wt% to 1 wt% of Li, 0.1 wt% to 0.5 wt% of Cu, and the balance of Zn.

It should be understood that, based on the material adopted by the stent of this embodiment, i.e. the composite metal wire material with the outer layer made of the zinc alloy and the core made of the magnesium alloy, the degradation rate of the zinc alloy of the outer layer is slow, so that sufficient service time can be obtained, and at the same time, the magnesium alloy of the core can still provide effective mechanical properties in the post-implantation degradation process under the protection of the zinc alloy of the outer layer. Moreover, the deformation processes of the two alloys are mutually coordinated and matched, the annealing temperatures are close, and the annealing treatment in the subsequent process is more facilitated.

Further, the magnesium alloy rod of the present embodiment has a diameter 2 to 4 times the wall thickness of the zinc alloy pipe, and the diameter of the magnesium alloy rod is 0.01 to 0.03mm (e.g., 0.02mm) smaller than the inner diameter of the zinc alloy pipe to place the magnesium alloy rod in the zinc alloy pipe.

And S120, carrying out hot extrusion treatment on the pressed cast ingot to form the composite metal bar.

Specifically, the pressed cast ingot formed in the step S110 is subjected to single-hole hot extrusion at an extrusion temperature range of 200-250 ℃ and an extrusion rate range of 1-3 mm/S to form a composite metal bar with a diameter range of 2-4 mm.

In some embodiments, the homogenized pressed ingot is subjected to single-hole hot extrusion, the extrusion temperature is set to 230 ℃, and the extrusion rate is set to 2mm/s, so that a composite metal bar with the diameter of 3mm is obtained, wherein the outer layer of the composite metal bar is made of zinc alloy, and the core of the composite metal bar is made of magnesium alloy.

S130, carrying out drawing treatment and annealing treatment on the composite metal bar to form the composite metal wire.

Specifically, in some embodiments, the composite metal rod is subjected to multiple drawing processes and annealing at an annealing temperature ranging from 150 ℃ to 300 ℃ to obtain a composite metal wire with a diameter ranging from 0.1mm to 0.3mm, please refer to fig. 3, which shows a cross section of the composite metal wire, wherein the inner core is a magnesium alloy rod 110, and the outer layer is a zinc alloy tube 120.

S140, weaving the composite metal wire to obtain the degradable composite metal woven stent.

Specifically, in this embodiment, the composite metal wire is woven by using a diamond structure as the weaving structure, the diamond structure refers to fig. 4, the composite metal wire is woven according to the diamond structure to obtain the degradable composite metal woven stent having the first mesh internal angle and the second mesh internal angle, and the stent refers to fig. 5.

The knitting method is not particularly limited, and for example, the knitting may be performed manually, or may be performed by a machine, as long as the degradable composite metal knitted stent obtained by knitting the composite metal wire material is obtained.

It should be further noted that, in this embodiment, the internal angles of the first meshes and the internal angles of the second meshes are not particularly limited, and may be set according to actual needs, for example, the internal angle range of the first meshes is set to 40 ° to 50 °, and the internal angle range of the second meshes is set to 130 ° to 140 °.

Illustratively, the woven structure selected based on the present embodiment is a diamond structure, and the first mesh internal angle and the second mesh internal angle of the stent are respectively set to be 45 degrees and 135 degrees, so that the stent has better supporting force and rebound elasticity.

The preparation method of the embodiment adopts ingot casting nested composite preparation, has no additional preparation process of a film layer, is simple in preparation process, and has lower requirements on storage conditions and convenient storage due to the fact that the outer layer is made of zinc alloy. In addition, the embodiment can promote the effective combination of the zinc alloy and the magnesium alloy interface through the homogenization treatment, the hot extrusion and the drawing process, and the preparation process can accelerate the diffusion of atoms at the interface, and the magnesium atoms in the zinc matrix or the zinc atoms in the magnesium matrix are increased in strength by a small increase, so that the formed interface layer additionally provides a part of improvement of the supporting strength, so that the stent obtained by the embodiment has excellent mechanical strength.

In another aspect of the present invention, a degradable composite metal woven stent is provided, which is prepared by the above-mentioned method for preparing a degradable composite metal woven stent.

The degradable composite metal woven stent obtained by the embodiment has an inner-layer and outer-layer composite structure, wherein the core part of the inner layer is made of magnesium alloy bars, and the outer layer is made of zinc alloy pipes. And the diameter range of the bracket is 3.5 mm-8 mm, and the length range is 12 mm-40 mm. Therefore, the outer layer of zinc alloy is slow in degradation speed, enough service time can be obtained, and meanwhile, the magnesium alloy of the core part can still provide effective mechanical properties in the degradation process after implantation under the protection of the outer layer of zinc alloy, namely, the degradable composite metal woven stent has slow degradation speed and excellent support performance, can be used for expanding and supporting the tubular tracts of a human body, such as blood vessels, biliary tracts, urethra and the like, and is simple and convenient to store.

The preparation method of the degradable composite metal woven stent will be further described with reference to several specific examples:

example 1

The preparation method of the degradable composite metal woven stent in the example comprises the following steps:

s1, selecting a magnesium alloy ingot and a zinc alloy ingot, machining the ingots into a magnesium alloy rod 110 and a zinc alloy pipe 120 with one closed end in a machining mode, placing the magnesium alloy rod into the zinc alloy pipe, placing the zinc alloy rod into a pressing die at 300 ℃, and carrying out homogenization treatment for 2 hours under the pressure of 100MPa to obtain a pressed ingot 130, wherein the pressing die is shown in figure 2.

It should be noted that the magnesium alloy ingot employed in this example has 5 wt.% Zn and the balance Mg, and the zinc alloy ingot has 0.5 wt.% Cu and the balance Zn.

Further, the magnesium alloy rod processed in this example had a diameter of 9mm, the zinc alloy pipe had a wall thickness of 3mm, and an inner diameter of 9.02 mm.

S2, performing single-hole hot extrusion on the homogenized and pressed ingot casting block at the extrusion temperature of 230 ℃ and the extrusion rate of 2mm/S to obtain a composite metal bar with the diameter of 3mm, wherein the outer layer of the bar is made of zinc alloy, and the core part of the bar is made of magnesium alloy.

S3, drawing the composite metal bar obtained in the step S2 for multiple times, and annealing at 250 ℃ to obtain the composite metal wire with the diameter of 0.3 mm.

S4, carrying out artificial weaving on the composite metal wire obtained in the step S3 to obtain the degradable composite woven stent. Wherein, the weaving process adopts a diamond structure as the weaving structure, and correspondingly, the internal angles of the first meshes and the second meshes of the obtained bracket are 45 degrees and 135 degrees respectively.

The diameter of the degradable composite metal braided stent obtained by the preparation method of the embodiment is 8mm, the length of the degradable composite metal braided stent is 40mm, and wires used for the stent are composite metal wires of which the outer layer is Zn-0.5Cu alloy and the core part is Mg-5Zn alloy.

Example 2

The preparation method of the degradable composite metal woven stent in the example comprises the following steps:

s1, selecting magnesium alloy ingots and zinc alloy ingots, and processing the ingots into magnesium alloy rods and zinc alloy pipes with one closed end in a mechanical processing mode. And then, placing the magnesium alloy rod in a zinc alloy pipe, integrally placing the zinc alloy pipe in a pressing die at 300 ℃, and carrying out homogenization treatment for 2h under the pressure of 100MPa to obtain a pressed ingot.

In the present embodiment, the magnesium alloy ingot components used are 1 wt.% Zn and 1 wt.% Ca, with the balance being Mg, and the zinc alloy ingot components are 0.1 wt.% Li, 0.1 wt.% Mn, with the balance being Zn.

Further, the magnesium alloy rod processed in this example had a diameter of 10mm, the zinc alloy pipe had a wall thickness of 2.5mm and an inner diameter of 10.02 mm.

S2, performing single-hole hot extrusion on the homogenized and pressed ingot casting block at the extrusion temperature of 230 ℃ and the extrusion rate of 2mm/S to obtain a composite metal bar with the diameter of 3mm, wherein the outer layer of the bar is made of zinc alloy, and the core part of the bar is made of magnesium alloy.

S3, performing multi-pass drawing on the composite metal bar obtained in the step S2, and annealing at 150 ℃ to obtain the composite metal wire with the diameter of 0.2 mm.

S4, carrying out artificial weaving on the composite metal wire obtained in the step S3 to obtain the degradable composite woven stent. Wherein, the weaving process adopts a diamond structure as the weaving structure, and correspondingly, the internal angles of the first meshes and the second meshes of the obtained bracket are 45 degrees and 135 degrees respectively.

The wire for a stent, which had a diameter of 6mm and a length of 25mm and was obtained by the manufacturing method of this example, was a composite metal wire having an outer layer of Zn-0.1Li-0.1Mn alloy and a core of Mg-Zn-Ca alloy, as shown in FIG. 3.

Example 3

The preparation method of the degradable composite metal woven stent in the example comprises the following steps:

s1, selecting magnesium alloy ingots and zinc alloy ingots, and processing the ingots into magnesium alloy rods and zinc alloy pipes with one closed end in a mechanical processing mode. And then, placing the magnesium alloy rod in a zinc alloy pipe, integrally placing the zinc alloy pipe in a pressing die at 300 ℃, and carrying out homogenization treatment for 2h under the pressure of 100MPa to obtain a pressed ingot.

The magnesium alloy ingot used in this example includes 3 wt.% Zn and 0.1 wt.% Ca, with the balance being Mg, and the zinc alloy ingot includes 1 wt.% Li, 0.1 wt.% Cu, and the balance being Zn.

Further, the magnesium alloy rod processed in this example had a diameter of 7.5mm, the zinc alloy pipe material had a wall thickness of 3.75mm and an inner diameter of 7.52 mm.

S2, performing single-hole hot extrusion on the homogenized and pressed ingot casting block at the extrusion temperature of 230 ℃ and the extrusion rate of 2mm/S to obtain a composite metal bar with the diameter of 3mm, wherein the outer layer of the bar is made of zinc alloy, and the core part of the bar is made of magnesium alloy.

S3, drawing the composite metal bar obtained in the step S2 for multiple times, and annealing at the temperature of 300 ℃ to obtain the composite metal wire with the diameter of 0.15 mm.

S4, carrying out artificial weaving on the composite metal wire obtained in the step S3 to obtain the degradable composite woven stent. Wherein, the weaving process adopts a diamond structure as the weaving structure, and correspondingly, the internal angles of the first meshes and the second meshes of the obtained stent are respectively 4 degrees' and 135 degrees.

The degradable composite metal braided stent obtained by the preparation method of the embodiment has the diameter of 4mm and the length of 15mm, and wires used by the stent are composite metal wires of which the outer layer is Zn-Li-0.1Cu alloy and the core part is Mg-3Zn-0.1Ca alloy.

Example 4

The preparation method of the degradable composite metal woven stent in the example comprises the following steps:

s1, selecting magnesium alloy ingots and zinc alloy ingots, and processing the ingots into magnesium alloy rods and zinc alloy pipes with one closed end in a mechanical processing mode. And then, placing the magnesium alloy rod in a zinc alloy pipe, integrally placing the zinc alloy pipe in a pressing die at 300 ℃, and carrying out homogenization treatment for 2h under the pressure of 100MPa to obtain a pressed ingot.

It should be noted that the magnesium alloy ingot employed in this embodiment has 2 wt.% Zn and the balance Mg, and the zinc alloy ingot has 0.5 wt.% Li and the balance Zn.

Further, the magnesium alloy rod processed in this example had a diameter of 9mm, the zinc alloy pipe had a wall thickness of 3mm, and an inner diameter of 9.02 mm.

S2, performing single-hole hot extrusion on the homogenized and pressed ingot casting block at the extrusion temperature of 230 ℃ and the extrusion rate of 2mm/S to obtain a composite metal bar with the diameter of 3mm, wherein the outer layer of the bar is made of zinc alloy, and the core part of the bar is made of magnesium alloy.

S3, drawing the composite metal bar obtained in the step S2 for multiple times, and annealing at 220 ℃ to obtain the composite metal wire with the diameter of 0.1 mm.

S4, carrying out artificial weaving on the composite metal wire obtained in the step S3 to obtain the degradable composite woven stent. Wherein, the weaving process adopts a diamond structure as the weaving structure, and correspondingly, the internal angles of the first meshes and the second meshes of the obtained bracket are 45 degrees and 135 degrees respectively.

The degradable composite metal braided stent obtained by the preparation method of the embodiment has the diameter of 3.5mm and the length of 12mm, and wires used by the stent are composite metal wires of which the outer layer is Zn-0.5Li alloy and the core is Mg-2Zn alloy.

Compared with the prior art, the invention provides a degradable composite metal woven stent and a preparation method thereof, and the degradable composite metal woven stent has the following beneficial effects: the preparation method disclosed by the invention is prepared by ingot casting nesting and compounding, has no additional preparation process of a film layer, is simple in preparation process, and has lower requirements on storage conditions because the outer layer is made of zinc alloy. Secondly, the invention can promote the effective combination of the zinc alloy and the magnesium alloy interface through the homogenization treatment, the hot extrusion and the drawing process, and the preparation process can accelerate the diffusion of atoms at the interface, while the magnesium atoms in the zinc matrix or the zinc atoms in the magnesium matrix are increased by a small amount to improve the strength, so the formed interface layer can additionally provide a part of the improvement of the supporting strength. Thirdly, the degradable composite metal braided stent obtained by the preparation method has an inner-layer and outer-layer composite structure, the degradation speed of the zinc alloy of the outer layer is slow, enough service time can be obtained, and meanwhile, the magnesium alloy of the core part can still provide effective mechanical properties in the degradation process after implantation under the protection of the zinc alloy of the outer layer. Fourthly, the stent obtained by the invention has mesh angles, so that the stent has better supporting force and rebound resilience.

It will be understood that the above embodiments are merely exemplary embodiments taken to illustrate the principles of the present invention, which is not limited thereto. It will be apparent to those skilled in the art that various modifications and improvements can be made without departing from the spirit and substance of the invention, and these modifications and improvements are also considered to be within the scope of the invention.