KR102191557B1 - Biodegradable stent using plasma enhanced chemical vapor deposition and its manufacturing method - Google Patents

Abstract

A biodegradable stent according to the present invention has surface properties of excellent biocompatibility. Specifically, the biodegradable stent has excellent hydrophilic surface properties, and has the effect of providing an activated surface with excellent porosity, pore size, and surface roughness. Although the biodegradable stent is a polymer stent with high surface hydrophilicity and high pore surface properties, the biodegradable stent has the effect of providing high mechanical properties such as stiffness and durability.

Description

Biodegradable stent using plasma enhanced chemical vapor deposition and its manufacturing method}

The present invention relates to a biodegradable stent using a plasma enhanced chemical vapor deposition method and a method of manufacturing the same.

With the recent aging society, coronary artery diseases such as angina and myocardial infarction and cerebrovascular diseases such as cerebral infarction and stroke have increased significantly, leading to death in adults. Coronary artery disease is a disease that causes sudden death due to heart attack due to a blockage of the coronary artery supplying blood to the heart, and a cerebral infarction or stroke is a disease that leaves serious sequelae such as hemiplegia and general paralysis even if death or recovery immediately occurs.

As described above, stents are widely used in the treatment of circulatory diseases such as fatal coronary artery disease and cerebrovascular disease, and a lot of attention is focused on technology development for improving the function.

When blood vessel stenosis occurs, the stent for vasodilation is used as an artificial scaffold that expands the occluded area by applying a physical force from the outside and maintains a space so that the expanded blood vessel is not constricted again. Currently, the field of application of the stent is expanding to various fields such as cardiovascular, femoral blood vessel, and biliary tract, and the use of such a stent has emerged as a great advantage as it can replace open surgery that burdens patients.

These stents are implanted as permanent stents in the canal that reinforce the narrowed, partially occluded, weakened, or abnormally dilated areas of blood vessels, or as temporary stents that provide treatment to damaged blood vessels. Stents can also be applied to the urethra and bile ducts, but are typically used after balloon angioplasty of blood vessels to prevent restenosis of damaged blood vessels.

Metallic materials, which are one of biocompatible materials, are mainly used for the stent.However, in the case of a conventional metallic stent, it has the advantage of having sufficient mechanical strength to prevent vascular stenosis, but at the same time, it has a mechanical strength that is too hard compared to the surrounding vascular tissue. Therefore, there was a problem such as not properly fusion with each other. In addition, due to its non-absorbable nature, the patient has the burden of living with foreign substances in the body for life. In addition, when the conventional metal stent is implanted, neointimal hyperplasia occurs due to damage to the vascular endothelium. Due to this, it has been reported that problems such as restenosis continue to occur within a few months.

WO 2015-023077 A1

It is an object of the present invention to provide a biodegradable stent having excellent biocompatibility and a method of manufacturing the same.

A specific object of the present invention is to provide a surface-activated biodegradable stent having excellent hydrophilic surface properties, porosity, pore size, and surface roughness, and a method for manufacturing the same.

In addition, a specific object of the present invention is to provide a biodegradable stent having high mechanical properties (stiffness, durability, etc.) and a method for manufacturing the same, even though it is a polymer material stent having high surface hydrophilicity and high pore surface properties.

The method of manufacturing a biodegradable stent according to the present invention includes plasma treatment on the stent containing a biodegradable polymer in a mixed fluid atmosphere containing at least one fluid selected from the group consisting of oxygen, nitrogen, and argon and methane. do.

In one example of the present invention, the biodegradable polymer may include any one or two or more selected from aliphatic polyester, polyamino acid, polyanhydride, and polyorthoester.

In one example of the present invention, the biodegradable polymer may include an aliphatic polyester, and the aliphatic polyester may include a lactic acid polymer.

In an example of the present invention, the fluid may contain oxygen or argon.

In an example of the present invention, the plasma treatment may be performed for 1 to 60 minutes.

In an example of the present invention, the plasma treatment may be performed at a pressure of 20 to 50°C and 50 to 500 mtorr.

In an example of the present invention, the plasma treatment may be RF plasma treatment using a plasma enhanced chemical vapor deposition method.

The biodegradable stent according to the present invention includes a non-porous stent skeleton comprising a biodegradable polymer; And a porous surface layer located on the stent skeleton and comprising a biodegradable polymer modified by plasma treatment and having surface irregularities.

In an example of the present invention, the surface irregularities may have a surface roughness of 50 to 120 nm.

In an example of the present invention, the pores of the porous surface layer may include open pores.

In an example of the present invention, the average thickness of the porous surface layer may be 1 to 5 μm.

In one example of the present invention, the biodegradable stent may have a water contact angle of 60 degrees or less by the porous surface layer.

In one example of the present invention, the biodegradable polymer may include poly-L-lactic acid.

The biodegradable stent according to an example of the present invention may have a wire shape having the non-porous stent skeleton as a core and the porous surface layer as a sheath.

The present invention may provide a vascular catheter, and in a vascular catheter according to an embodiment of the present invention, unit lines connected to each other at ends form a tubular shape in which unit lines are spaced apart from each other in the longitudinal direction of the tube and are arranged in parallel, An outer peripheral surface portion including one or more connecting lines to connect; And a hollow core portion formed inside the outer circumferential portion, wherein the unit line and the connection line have a wire shape having a non-porous stent skeleton as a core and a porous surface layer as a sheath. It may be a stent.

The biodegradable stent according to the present invention has an effect of having excellent biocompatibility surface properties.

In addition, the biodegradable stent according to the present invention has excellent hydrophilic surface properties, and an activated surface having excellent porosity, pore size, and surface roughness.

In addition, although the biodegradable stent according to the present invention is a polymer material stent having high surface hydrophilicity and high pore surface properties, it has an effect of having high mechanical properties (stiffness, durability, etc.).

1 is a process diagram schematically showing the principle of a method of manufacturing a biodegradable stent according to the present invention and a surface modification reaction of a biodegradable polymer by plasma treatment in a mixed fluid atmosphere in the manufacturing method.
2 is an image obtained by observing the surface layer of the stent before plasma treatment, that is, the untreated stent (untreated biodegradable polymer) in Example 1 with a scanning electron microscope.
3 is an image obtained by observing the surface layer of the biodegradable stent prepared in Example 1 with a scanning electron microscope.
4 is an image of a cut surface of the biodegradable stent prepared in Example 1 observed with a scanning electron microscope.
5 is an image obtained by observing the surface layer of the biodegradable stents prepared in Comparative Examples 1 to 3 with a scanning electron microscope. The left image is for Comparative Example 1, the center image is for Comparative Example 2, and the right image is for comparison. This is an image for the case of Example 3.
6 is an image of observing the surface structure of the surface layers of the biodegradable stents prepared in Examples 1 to 3 and Comparative Example 4 with an atomic force microscope.
7 shows the results obtained by measuring the water contact angle with respect to the surface layer of the biodegradable stents prepared in Examples 1 to 3 and Comparative Example 4.
8 is a diagram schematically showing the structure and shape of a stent (catheter) according to an example of the present invention.

Hereinafter, a biodegradable stent and a manufacturing method thereof according to the present invention will be described in detail with reference to the accompanying drawings.

The drawings described in this specification are provided as an example in order to sufficiently convey the spirit of the present invention to those skilled in the art. Accordingly, the present invention is not limited to the drawings to be presented and may be embodied in other forms, and the drawings may be exaggerated to clarify the spirit of the present invention.

Unless otherwise defined, technical terms and scientific terms used in the present specification have the meanings commonly understood by those of ordinary skill in the art to which this invention belongs, and the gist of the present invention in the following description and accompanying drawings A description of known functions and configurations that may unnecessarily obscure will be omitted.

The singular form of terms used in the present specification may be interpreted as including the plural form unless otherwise indicated.

Unless otherwise defined, the unit of% used in this specification means% by weight.

The method of manufacturing a biodegradable stent according to the present invention is a mixture comprising at least one fluid selected from the group consisting of oxygen (O ₂ ), nitrogen (N ₂ ) and argon (Ar) and methane (Methane, CH ₄ ) And plasma treating the stent containing the biodegradable polymer in a fluid atmosphere.

As the biodegradable stent according to the present invention is prepared by treating plasma with a biodegradable polymer, but treating plasma in a mixed fluid atmosphere containing the fluid and methane, the surface layer of the biodegradable polymer has high surface hydrophilicity. Is given.

In the present specification, the term “surface layer” refers to a surface portion having a certain depth in the inner direction from the surface of the biodegradable polymer. As a specific example, the surface portion may mean a region having a thickness in the range of 1 to 20 µm, specifically 1 to 10 µm, and more specifically 1 to 5 µm. That is, the biodegradable polymer according to an example of the present invention may include a surface layer having an average thickness in the above range.

As described above, in the above step, the plasma treatment atmosphere refers to a mixed fluid phase containing the fluid and methane, and the surface layer of the stent is modified by plasma treatment in this atmosphere to exhibit high surface hydrophilicity. Free radicals are generated during plasma treatment, and all active substances present in the plasma are electrons, ions, free radicals, atoms, and molecules. electronic states), that is, mainly involved in surface modification and film growth in metastable and resonance states. In particular, free radicals of CH3· and CH· species generated by dissociation from methane in the mixed fluid may play a role of improving surface properties together with the fluid in the mixed fluid.

That is, the mixed fluid or active substances derived therefrom may act on the surface of the biodegradable polymer to modify the surface, and at this time, the modified biodegradation of a composition and/or composition ratio different from that of the biodegradable polymer before plasma treatment Sex polymers can be formed as a surface layer. In detail, the active material approaches the plasma boundary (electrode, wall, substrate, etc.) by specific movement mechanisms such as diffusion, discharge flow, and gas flow, and interacts with the upper surface of the biodegradable polymer. Do it. By performing plasma treatment in such a mixed fluid atmosphere, a surface layer having a dense structure with little mutual dissolution with the polymer is formed on the biodegradable polymer. Even if the biodegradable polymer has insulating properties, the active material formed by the plasma in the mixed fluid atmosphere is accelerated by the grid and sterically injected into the surface of the polymer material to form a number of free radicals. As a result, a double bond is formed in the polymer chains or a crosslinking reaction proceeds to form a bond between the chains and the chains of the polymer, so that a passage through which electrons can be transferred smoothly is formed on the surface of the polymer and the surface resistance is greatly reduced. Therefore, during the plasma treatment process, the surface layer becomes rich in crosslinking properties, an excellent environment for impurity doping is created, and high surface hydrophilicity is imparted.

In particular, when the fluid contains any one or more selected from argon and oxygen, the physical structure of the surface layer, that is, surface activation is performed to improve the porosity, surface irregularities, etc., so that the stent includes open pores. It can have high porosity and high roughness. That is, the fluid included in the mixed fluid may include oxygen, nitrogen, argon, or two or more selected from these, as described above, but oxygen or argon in terms of higher improvement of physical surface properties such as porosity and surface irregularities. It may be more preferable to include.

In order to simultaneously have the above-described high surface hydrophilic properties and high surface activity (porosity, surface unevenness) properties, it is implemented only when the mixed fluid contains methane and contains oxygen or argon, and does not contain methane, or does not contain oxygen or argon. In case high surface activity properties may not be implemented.

In the mixed fluid, the ratio of fluid and methane is not largely limited, for example, 20 to 500 parts by volume of methane, specifically 100 to 500 parts by volume, more specifically 150 to 300 parts by volume, based on 100 parts by volume of the fluid. Can be. Alternatively, in the above step, the mixed fluid may be introduced into the biodegradable polymer at a specific flow rate, and at this time, the flow rate ratio of the fluid and methane may also be applied as a ratio of the above range. When the ratio of fluid and methane satisfies the above range, when ions are accelerated and injected into the surface of a three-dimensional polymer material and a plurality of free radicals are formed, the polymer chain is crosslinked by the radicals including double bonds. By doing so, a chain-chain bond is formed. In particular, a passage through which electrons can move is formed on the polymer surface, so that the effect of further reducing the surface resistance can be realized.

Specifically, the biodegradable stent according to the present invention includes a non-porous stent skeleton comprising a biodegradable polymer; And a porous surface layer located on the stent skeleton and comprising a biodegradable polymer modified by plasma treatment and having surface irregularities.

The surface irregularities are items that can be appropriately adjusted by adjusting plasma treatment conditions, etc., which will be described later according to the required purpose, but for example, the surface roughness is 30 to 300 nm, specifically 40 to 200 nm, more specifically 50 to 120 It may be preferred to be nm.

The surface layer is a porous surface layer and includes pores, and may specifically include open pores. As a preferred example, the surface layer may have a porosity of 5 to 60%, specifically 10 to 50%, and more specifically 15 to 30%.

In particular, the biodegradable stent according to the present invention is a polymer material stent having high surface hydrophilicity and high pore surface properties, different from the formation of a surface layer by accompanying a separate polymer coating process. In addition, there is an effect of having high mechanical properties (stiffness, durability, etc.).

The biodegradable polymer is a polymer that naturally decomposes over time in the human body, and a polymer capable of implementing the effects mentioned in the present specification, specifically, surface properties on the surface of the biodegradable polymer by plasma treatment. Any polymer capable of forming a hydrophilic and porous surface layer by being imparted to it is fine. As a specific example, the biodegradable polymer includes any one or two or more selected from aliphatic polyester, poly amino acid (PAA), polyanhydride, and polyortho ester (POE). It may be desirable to do.

More preferably, the biodegradable polymer may include an aliphatic polyester. As a specific example, the aliphatic polyester may include any one or two or more selected from lactic acid polymers, polyglycolic acid (PGA), and poly-ε-caprolactone (PCL). .

Even more preferably, the aliphatic polyester may include a lactic acid polymer, and a preferred example thereof, the lactic acid polymer is poly-L-lactic acid (PLLA), poly-DL- Lactic acid (Poly-DL-lactic acid, PDLLA), polylactic acid (PLA) and lactic acid-glycolic acid copolymer (Poly (lactide-co-glycolide), PLGA), etc. Among these, poly-L-lactic acid may be more preferable in that a porous surface layer can be formed during plasma treatment.

The weight average molecular weight of the biodegradable polymer may be any one having a value of a conventional one used in the field of biodegradable polymers, for example, 10,000 to 150,000 g/mol, and specifically, 3,000 in the case of poly-L-lactic acid. To 120,000 g/mol. However, this has been described as a specific example, and the present invention is not necessarily limited thereto.

As described above, the biodegradable stent according to the present invention has a high surface hydrophilic effect. Specifically, the biodegradable stent has a water contact angle of 70 degrees or less, preferably 60 degrees or less, more preferably 50 degrees or less, and even more preferably 40 degrees or less by the porous surface layer. It can be, and the lower limit value is not very limited, but may be, for example, 20 degrees.

In the above step, the plasma treatment may be any means capable of exposing the biodegradable polymer to the plasma by forming a plasma, and specifically, it may be performed using a plasma-enhanced chemical vapor deposition (PECVD) method. have. In this case, the plasma may be an RF plasma formed using radio frequency (RF) power.

The plasma treatment conditions may refer to those known in the field of surface modification of a material through plasma treatment, and are not greatly limited as long as plasma is formed in the mixed fluid atmosphere and the above-described characteristics and effects can be realized, but plasma to be described later It may be desirable to satisfy processing conditions such as processing time, plasma processing temperature, and plasma processing pressure.

In a preferred example, the plasma treatment is a matter that can be adjusted according to the required surface characteristics, so the treatment time is not greatly limited, but it is performed for 0.5 minutes or more, specifically 1 minute or more, and more specifically 2 minutes or more. And the upper limit may be 60 minutes. If this is satisfied, the stent may have a surface layer having high surface hydrophilicity and high surface activity.

As a preferred example, the plasma may be a low-temperature plasma, and specifically, the plasma treatment may be performed at a temperature of 20 to 50°C. If this is satisfied, the stent may have a surface layer having high surface hydrophilicity and high surface activity.

In addition, the plasma treatment may be performed at a pressure of 50 to 500 mtorr, specifically 100 to 200 mtorr, and if this is satisfied, the stent may have a surface layer having high surface hydrophilicity and high surface activity. During RF plasma treatment, the reaction temperature and pressure (vacuum degree) in a mixed fluid atmosphere containing methane may have a close relationship to the effect of surface modification, and the reaction to the surface deformation can be controlled by controlling the temperature and pressure.

In an example of the present invention, the plasma treatment may be performed at 5 to 50 MHz RF, and may be performed at a voltage of 300 to 3,000 V. However, this has been described as a specific example, and the present invention is not necessarily limited thereto.

The biodegradable stent according to the present invention may mean a medical stent inserted into the human body, and as an example, a permanent stent or a temporary stent inserted into the human body may be mentioned. The stent is generally used for insertion into a blood vessel, but is not limited as long as it is a stent for a purpose that can be inserted into the human body, such as a urethral duct or a bile duct. Typically, biodegradable stents can be used after balloon angioplasty of blood vessels to prevent restenosis of damaged blood vessels.

As a specific example, the biodegradable stent may be a wire-shaped stent having the non-porous stent skeleton as a core and the porous surface layer as a sheath.

As a specific example, as shown in FIG. 7, the biodegradable stent according to the present invention may be used as a vascular catheter. The vascular catheter may include an outer peripheral surface portion having a tubular shape in which unit lines connected to each other at ends are spaced apart from each other in a longitudinal direction of the tube and disposed in parallel, and including at least one connecting line connecting the unit lines; And a hollow core portion formed inside the outer circumferential portion; wherein the unit line and the connection line have a wire shape having a non-porous stent skeleton as a core and a porous surface layer as a sheath. It may be a sexual stent.

However, the biodegradable stent according to the present invention may have various structures and shapes in addition to the above-described form, and may be used for the above-described field and purpose, so it is not limited thereto.

Hereinafter, the present invention will be described in detail through examples, but these are for explaining the present invention in more detail, and the scope of the present invention is not limited by the following examples.

A mixed gas containing argon and methane in a volume ratio of 0.5:1 was injected into a reaction tube containing an untreated stent (untreated biodegradable polymer) made of poly-L-lactic acid (Poly(L-lactide), RESOMER, EVONIK). In this state, a surface-modified biodegradable stent was prepared by treating the stent with RF plasma (RF PLAMSA). The RF plasma treatment was performed using a plasma enhanced chemical vapor deposition method, and was performed at 35° C. and 150 mtorr pressure for 3 minutes. Further, the RF plasma treatment was performed at a voltage of 800 V and an RF of 13.56 MHz.

In Example 1, a surface-modified biodegradable stent was prepared in the same manner as in Example 1, except that oxygen was used instead of argon.

In Example 1, a surface-modified biodegradable stent was prepared in the same manner as in Example 1, except that nitrogen was used instead of argon.

[Comparative Example 1]

In Example 1, a surface-modified biodegradable stent was prepared in the same manner as in Example 1, except that it was performed in an argon atmosphere without using methane instead of a mixed fluid atmosphere containing argon and methane.

[Comparative Example 2]

In Example 1, a surface-modified biodegradable stent was prepared in the same manner as in Example 1, except that it was performed in an oxygen atmosphere without using methane instead of a mixed fluid atmosphere containing argon and methane.

[Comparative Example 3]

In Example 1, a surface-modified biodegradable stent was prepared in the same manner as in Example 1, except that it was performed in a nitrogen atmosphere without using methane instead of a mixed fluid atmosphere containing argon and methane.

[Comparative Example 4]

In Example 1, a surface-modified biodegradable stent was prepared in the same manner as in Example 1, except that it was performed in a methane atmosphere without using argon, instead of a mixed fluid atmosphere containing argon and methane.

[Experimental Example 1]

<Stent surface observation>

The surface layers of the biodegradable stents prepared in Examples 1 to 3 and Comparative Examples 1 to 3 were observed with a scanning electron microscope (SEM).

First, as shown in FIG. 2, it can be seen that the untreated stent, that is, the biodegradable stent that is not plasma-treated, has almost no pores and irregularities inside the stent and the surface portion.

As shown in FIG. 3, the biodegradable stent prepared in Example 1 had a surface layer having a very high surface roughness, and various pores having different shapes and sizes from the outside to the inside of the surface layer, especially open pores, were very large. It can be confirmed that it is formed.

In addition, in order to specifically confirm the inside of the surface layer of the stent of Example 1, as a result of observing the cut surface with a scanning electron microscope, it can be seen that the surface layer is formed to a thickness of 100 to 150 μm, as shown in FIG. It had a constant thickness with almost no variation in its thickness according to one area.

On the other hand, Figure 5 is an image of the surface layer of the biodegradable stent prepared in Comparative Examples 1 to 3 observed with a scanning electron microscope (left image: Comparative Example 1, center image: Comparative Example 2, right image: Comparative Example 3) In the case of Comparative Examples 1 to 3 in which methane was not used, it can be seen that even though the plasma treatment was performed, no pores were formed in the surface layer, and there was no difference before and after the plasma treatment.

[Experimental Example 2]

<Measurement of surface structure of stent surface>

In order to more specifically analyze the surface structures of the biodegradable stents prepared in Examples 1 to 3 and Comparative Example 4, the surface layer was observed and analyzed with an atomic force microscope (AFM).

As a result, as shown in FIG. 6, in the case of Example 1 and Example 2, that is, the stent produced by plasma treatment in a mixed fluid atmosphere containing methane and argon or oxygen has a surface layer having a high surface roughness. It can be confirmed that it was formed.

On the other hand, when argon or oxygen was not used even though methane was used, specifically, in the case of Example 3 in which a mixed fluid containing nitrogen and methane was used and Comparative Example 4 in which a fluid containing methane was used, very low surface roughness It can be seen that the surface layer having is formed.

[Experimental Example 3]

<Measurement of water contact angle on the surface of the stent>

7 shows the results obtained by measuring the water contact angle with respect to the surface layer of the biodegradable stents prepared in Examples 1 to 3 and Comparative Example 4. From FIG. 7, in the case of Examples 1 to 3, that is, the stent produced by plasma treatment in a mixed fluid atmosphere containing methane and containing argon, oxygen, or nitrogen is less than 60 degrees at 2.5 minutes of plasma treatment. It can be confirmed that it has high surface hydrophilicity due to its excellent water contact angle.

Furthermore, in the case of Examples 1 and 2 in which argon or oxygen was used together with methane, respectively, compared to the case of Example 3 in which nitrogen was used together with methane, it was confirmed that a surface layer having high hydrophilicity was formed in a shorter time. have.

On the other hand, in the case of Comparative Example 4 performed in a methane atmosphere without using argon, oxygen or nitrogen, it can be confirmed that the water contact angle before and after plasma treatment is almost 80 degrees, so that the surface is not modified to be hydrophilic.

Therefore, it can be seen that in order to simultaneously have the above-described high surface hydrophilic properties and high surface pore properties, plasma treatment should be performed in a mixed fluid atmosphere containing methane and oxygen or argon.

Claims (15)

As a method for producing a stent containing a biodegradable polymer,
Any one or more fluids selected from the group consisting of oxygen, nitrogen and argon; And methane (CH ₄ ); Plasma treatment on the surface of the biodegradable polymer of the stent in a mixed-fluid atmosphere containing a biodegradable stent. The method of claim 1,
The fluid is a method of manufacturing a biodegradable stent comprising at least one selected from oxygen and argon. The method of claim 1,
The biodegradable polymer is a method for producing a biodegradable stent comprising at least one selected from the group consisting of aliphatic polyester, polyamino acid, polyanhydride and polyorthoester. The method of claim 3,
The biodegradable polymer includes an aliphatic polyester, and the aliphatic polyester is a method of manufacturing a biodegradable stent comprising a lactic acid polymer. The method of claim 1,
The plasma treatment is a method of manufacturing a biodegradable stent performed for 1 to 60 minutes. The method of claim 5,
The plasma treatment is a method of manufacturing a biodegradable stent performed at a pressure of 20 to 50° C. and 50 to 500 mtorr. The method of claim 1,
The plasma treatment is a method of manufacturing a biodegradable stent, which is an RF plasma treatment using a plasma enhanced chemical vapor deposition method. A non-porous stent skeleton containing a biodegradable polymer; And
It is located on the stent skeleton, includes a surface portion of the biodegradable polymer modified by plasma treatment, and a porous surface layer having surface irregularities; includes,
The plasma treatment includes at least one fluid selected from the group consisting of oxygen, nitrogen, and argon; And methane (CH ₄ ); Biodegradable stent that is performed in a mixed fluid atmosphere containing. delete The method of claim 8,
The surface irregularities are biodegradable stents having a surface roughness of 40 to 120 nm. The method of claim 8,
The pores of the porous surface layer are biodegradable stents including open pores. The method of claim 8,
The average thickness of the porous surface layer is 1 to 5 ㎛ biodegradable stent. The method of claim 8,
The biodegradable stent is a biodegradable stent having a water contact angle of 60 degrees or less by the porous surface layer. The method of claim 8,
The biodegradable polymer is a biodegradable stent containing poly-L-lactic acid. As a vascular catheter,
An outer circumferential surface portion comprising unit lines having ends connected to each other forming a tubular shape arranged in parallel by being spaced apart from each other in the longitudinal direction of the tube, and including at least one connecting line connecting the unit lines; And
Has a tubular shape including a; hollow core portion formed inside the outer peripheral surface portion,
The unit line and the connecting line are biodegradable stents according to any one of claims 8 and 10 to 14 having a wire shape having a non-porous stent skeleton as a core and a porous surface layer as a sheath, a vascular catheter.

Images