KR20150131716A - Stent - Google Patents

Abstract

The present invention relates to a stent. The stent according to the present invention comprises: a stent main body which has grid or mesh type nets as metal wires are crossing each other, and is in a tube shape with a hollow portion inside; and a coating film which surrounds the surface of the stent main body. The coating film is formed from a coating solution which is made by mixing a liquid silicon polymer and hydrophobic polymer particles with a friction coefficient smaller than that of the silicon polymer. According to the present invention, the coating film having a low friction prevents materials passing through lesions from being deposited on the surface of the stent and prevents the direct contact between the lesions of a biliary tract and blood vessels and the materials passing through the stent. The contact surface of the coating film formed on the stent supports the inner wall of the biliary tract and the blood vessels so as to prevent the restenosis of the biliary tract and the blood vessels due to neointima growing inside the stent. The wear resistance and elasticity of an existing silicon coated stent is maintained as much as possible so as to be applied to a variety of lesions.

Description

Stent {STENT}

The present invention relates to a stent.

When the flow of blood or body fluids such as blood vessels and biliary ducts is not smooth due to the occurrence of malignant or benign diseases, various diseases may occur. In the case of blood vessels, blood circulation disorder and muscle pain may be induced. In severe cases, ischemic ulcers It may be necessary to cut the site.

In addition, in the case of bile ducts, the tumor is narrowed or closed, and bile excretion is not smooth, fever, jaundice, itching, sepsis and other symptoms may occur.

In order to treat these diseases, the status of blood vessels and bile ducts is checked through endoscopic and X-ray examination, and the vessels and bile ducts in which stenosis has developed are inserted into vessels and bile ducts Extension of the vessels and biliary ducts to expand the lining is underway.

However, this enlargement can be temporarily improved due to chronic shrinkage of vessels and bile ducts and neointimal hyperplasia. However, there is a problem in that restoration of blood vessels and biliary vessels narrowing or clogging after the procedure may occur.

In order to solve such a problem, in Korean Patent Laid-Open Publication No. 2012-0138974 (Announcement: 2012.12.27, hereinafter referred to as prior art), after the angioplasty, the blood vessel is inserted into the blood vessel to support the inner wall of the blood vessel, Stent to prevent vessel restenosis caused by chronic contraction of the stent.

However, in the prior art, since the stent supporting the blood vessel is composed only of a metal wire, substances such as blood, bile and protein fragments that pass through the lesion are deposited on the stent and can interfere with the flow of blood and body fluids, There is a problem that the lesion site may be worsened due to the substance passing through the lesion site, and the new intimal membrane may proliferate into the stent through the gap of the wire to cause restenosis.

Disclosure of the Invention The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to prevent deposition of a substance passing through a lesion site, to protect a lesion site from a substance passing through blood vessels and bile ducts, The present invention also provides a stent for preventing stenosis.

To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is provided a stent comprising: a stent body in the form of a tube having metal wires crossing each other to form a lattice or mesh network; And a coating film formed to surround the surface of the stent body. The coating film may be formed of a coating solution in which a silicone polymer prepared in a solution form and a hydrophobic polymer particle having a coefficient of friction lower than that of the silicone polymer are stirred.

The shape memory alloy constituting the stent body may be Ni (Ni) and Nitinol having titanium (Ti) as a main component.

The coating solution may be prepared by adding 7 wt% or less of the hydrophobic polymer particles to the silicon polymer solution.

In addition, the hydrophobic polymer particles may be PTFE (poly tetra fluoro ethylene) particles having a friction coefficient of 0.05 to 0.20 N.

As described above, the present invention has the following effects.

First, through the coating film having low frictional force, it is possible to prevent the deposition of the substance passing through the lesion site on the surface of the stent.

Second, the coating film formed on the stent can prevent the material passing through the lesion area of the bile duct and the blood vessel from contacting the lesion area through the inside of the stent.

Third, since the contact surface of the coating film formed on the stent supports the bile duct and the inner wall of the blood vessel, it is possible to prevent restenosis of the bile duct and blood vessel caused by proliferation of the new inner membrane into the stent.

Fourth, it can be applied to various lesion sites by minimizing the deposition of PTFE particles and minimizing the deposition of the material while minimizing the wear resistance and the decrease in elasticity of the coating film.

1 is a perspective view illustrating a stent according to an embodiment of the present invention.
FIG. 2 is a graph showing tensile strength and elongation of a coating film having different amounts of PTFE particles added to a coating solution for forming a coating film of a stent according to an embodiment of the present invention, and a conventional silicone coating film.
3 is a flowchart illustrating a method of manufacturing a stent according to an embodiment of the present invention.

The preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings, in which the technical parts already known will be omitted or compressed for simplicity of explanation.

< Stent  Configuration >

1 is a perspective view illustrating a stent according to an embodiment of the present invention.

The stent 100 according to an embodiment of the present invention may include a stent body 110 composed of a metal wire 112 and a coating film 120 formed of a silicon polymer 122 and PTFE particles 124 .

The stent body 110 may have a plurality of metal wires 112 each having a corrugated shape along the longitudinal direction connected to various shapes such as a lattice shape or a mesh shape and a cylindrical shape having a hollow in the longitudinal direction.

The metal wire 112 constituting the stent body 110 is made of Nitinol which is a nickel-titanium alloy and the stent body 110 is expanded or contracted in the circumferential direction The stent body 110 inserted into the lesion of the biliary tract and the blood vessel can be expanded toward the inner wall of the bile duct and the blood vessel to support the inner wall.

The coating film 120 is formed to surround the surface of the stent body 110 to prevent the substance passing through the stent 100 provided at the lesion portion from contacting the lesion site.

Here, the coating film 120 may be formed of a coating solution in which the PTFE particles 124, which are prepared by stirring the PTFE particles 124 in the solution-type silicon polymer 122, are uniformly dispersed.

The silicone polymer 122 may have a tensile strength of 14.6 N and an elongation of 940%.

The PTFE particles 124 may be made of polytetrafluoroethylene (PTFE) in powder form.

Here, PTFE is a hydrophobic fluorine-based polymer having a low coefficient of friction of 0.05 to 0.20N.

On the other hand, the PTFE particles 124 to be added to the silicon polymer 122 in the form of a solution may be 7 wt% or less, which will be described with reference to FIG.

FIG. 2 is a graph showing tensile strength and elongation of a coating film having different amounts of PTFE particles added to a coating solution for forming a coating film of a stent according to an embodiment of the present invention, and a conventional silicone coating film.

2, the tensile strength (N) and the elongation (%) of the silicone polymer 122 and the comparative group in which the content ratio of the PTFE 124 particles were different from the solution type silicone polymer 122 were measured, Respectively.

[Table 1]

Referring to Table 1, it can be seen that the coating film formed of only the silicone polymer 122 has a tensile strength of 14.6 N and an elongation of 940%.

The coating film 120 formed on the stent 100 according to the present invention minimizes the decrease in the tensile strength and the elongation of the silicone polymer 122 while minimizing the deposition of blood, bile and protein residues in the stent 100 It is preferable to form the coating film 120 using a coating solution in which 7 wt% or less of the PTFE particles 124 are added to the silicon polymer 122 in the form of a solution.

Accordingly, the stent 100 having the coating film 120 excellent in hydrophobicity, abrasion resistance, and stretchability can be applied to various lesion sites regardless of the blood vessel and bile duct structures.

< Stent  Manufacturing method >

One. Stent  Body preparation steps  ( S100 )

3 is a flowchart illustrating a method of manufacturing a stent according to an embodiment of the present invention.

A step of preparing the stent body 110 so that the coating film 120 can be uniformly formed on the stent body 110 is performed.

Here, the stent body 110 may be manufactured by winding a metal wire 112 made of nitinol having a diameter of about 50 to 150 microns into a net shape on a metal cylinder, followed by heat treatment. Here, the heat treatment is preferably performed at a temperature of 400 to 500 DEG C for 20 to 40 minutes.

After the heat-treated stent body 110 is completely cooled, the ultrasonic washing machine is washed with an ethanol and distilled water mixed solvent for 1 hour so that the coating film 120 can be uniformly formed on the surface of the stent body 110, The stent body 110 is dried in a hot air drier at 50 to 70 ° C. for 12 to 24 hours after the foreign substance attached to the surface of the body 110 is removed and then the stent body 110 is inserted into the coating jig .

In addition, the stent body 110 can be manufactured by processing a tube-shaped metal through a laser cutting method.

2. Coating solution preparation step  ( S200 )

Thereafter, a step of preparing a coating solution for forming the hydrophobic coating film 120 on the stent body 110 is performed (S200)

Here, the coating solution may be prepared by adding enough PTFE particles 124 at a concentration of 7 wt% or less to the silicon polymer 122 in the form of a solution, and then sufficiently stirring the PTFE particles 124 so that the PTFE particles 124 can be uniformly dispersed .

3. Coating film  Forming step  ( S300 )

A step of applying the prepared coating solution to the surface of the stent body 110 mounted on the coating jig is performed (S300)

Here, the coating solution may be applied to the stent body 110 by dipping, brushing, spraying, electrospinning, or the like.

Thereafter, the stent body 110 to which the coating solution is applied is placed in a drying oven at 35 ° C, followed by primary drying for 30 minutes, followed by drying in a drying oven at 180 ° C for 3 hours.

The stent 100 of the present invention can be manufactured by separating the stent 100 from which the drying of the coating film 120 has been completed from the coating jig.

As a result, it is possible to prevent the material passing through the lesion area from being deposited on the surface through the coating film having a low friction force, and to minimize the decrease in abrasion resistance and stretchability of the existing silicone coating film, Provided is a stent which is provided at a lesion site to protect a lesion site from contact with a substance passing through the inside of the stent and to prevent the neointima of the lesion site from being proliferated inside the stent by closely supporting the inner wall of the lesion site .

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. And the scope of the present invention should be understood as the following claims and their equivalents.

100: stent
110: stent body
112: metal wire
120: Coating film
122: Silicone polymer
124: PTFE particles

Claims (4)

A stent body in the form of a tube in which metal wires cross each other to form a lattice or mesh network, and a hollow inside; And
And a coating film covering the surface of the stent body,
Wherein the coating film is formed of a coating solution in which a silicone polymer prepared in a solution form and a hydrophobic polymer particle having a friction coefficient lower than that of the silicone polymer are stirred
Stent.
The method according to claim 1,
Wherein the metal wire constituting the stent body is Nitinol containing nickel (Ni) and titanium (Ti) as a main component
Stent.
The method according to claim 1,
Wherein the coating solution is prepared by adding 7 wt% or less of the hydrophobic polymer particles to the silicon polymer solution
Stent.
The method according to claim 1,
Wherein the hydrophobic polymer particles are polytetrafluoroethylene (PTFE) particles having a coefficient of friction of 0.05 to 0.20 N
Stent.

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