KR102111753B1 - Surface modified stent and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a surface-modified stent and a method for manufacturing the same, including a metal alloy for a stent (Stent), and a surface-modified stent comprising an area where roughness is formed on at least a portion of the surface.

Description

Surface modified stent and its manufacturing method {SURFACE MODIFIED STENT AND MANUFACTURING METHOD THEREOF}

The present invention relates to a surface-modified stent and a method for manufacturing the same. More specifically, the surface roughness is formed on the surface of the stent, and relates to a surface-modified stent that promotes or inhibits the growth of specific cells and a method of manufacturing the same.

In general, stent (stent) is a material widely used in the clinic to prevent the narrowing of the body organs or blood vessels, aneurysms, esophageal and gastrointestinal tract, narrowing of the biliary tract, narrowing of the ureter, etc. The stent may be inserted into a region where the flow is not smooth to solve a problem that inhibits the flow of fluids such as blood and various enzymes in blood vessels, biliary tracts, ureters, and the like. The stent inserted into the above site can force the inserted site to expand, thereby allowing fluids and enzymes to have a smooth flow.

At this time, it is manufactured to have a cylindrical shape using shape memory alloys as a material for the stent. In addition, the stent may be connected to one or more stents according to the formation of blood vessels, biliary tracts, ureters, etc. to be inserted.

On the other hand, when such a stent is inserted into a blood vessel, endothelial cells around the region where the stent is inserted are damaged and smooth muscle cells, which are muscle cells, penetrate. If the continuous penetration and growth of smooth muscle cells becomes excessive, a problem of restenosis, in which the blood vessel in which the stent is inserted is blocked again, may occur.

That is, when the endothelial cells surround the stent during the stent procedure, a new inner wall of the blood vessel is formed, and the stent can function properly. However, at this time, as the muscle cells constituting the blood vessels, smooth muscle cells involved in contraction or wound healing of blood vessels proliferate around the stent and cause restenosis.

Accordingly, there is a need for technology development to prevent the side effects caused by the stent insertion as described above, and to allow the stent to continue to function after the procedure.

Therefore, the present invention is to solve a number of problems, including the above problems, by forming a region having a roughness value in the nanometer to micrometer on the surface to suppress the proliferation of smooth muscle cells, endothelial cell proliferation It is an object to provide a surface-modified stent to promote.

In addition, the present invention aims to effectively suppress thrombosis and restenosis problems after stent treatment by optimizing the shape and mobility characteristics of smooth muscle cells and endothelial cells using the surface-modified stent.

According to one aspect of the present invention for solving the above problems, a surface-modified stent is provided that includes a metal alloy for a stent and includes an area where roughness is formed on at least a portion of the surface.

Further, according to an embodiment of the present invention, the surface may include a region in which the roughness is formed in a region of 50% or more.

Further, according to an embodiment of the present invention, at least one region of the roughness-formed region may be formed in one direction spaced apart from each other with a predetermined width to form a repeated pattern.

Further, according to an embodiment of the present invention, the illuminance may have a value ranging from 35 nm Ra to 840 nm Ra.

Further, according to an embodiment of the present invention, the illuminance may have a value in the range of 200 nm Ra to 840 nm Ra.

And, according to one aspect of the present invention for solving the above problem, the step of preparing a stent comprising a metal alloy and at least a portion of the surface of the stent nanosecond (nano second) laser pulse width of at least one laser A method of manufacturing a surface-modified stent is provided, including irradiating, forming roughness on at least a portion of the surface of the stent.

Further, according to an embodiment of the present invention, in the step of forming the illuminance, the laser may be irradiated in a direction spaced apart from each other with a certain width on the surface, and a repeated pattern may be formed on the surface.

In addition, according to an embodiment of the present invention, in the step of forming the illuminance, the value of the illuminance may increase as the laser is irradiated repeatedly.

Further, according to an embodiment of the present invention, in the step of forming the illuminance, the illuminance may be formed by irradiating the laser once to 32 times.

Further, according to an embodiment of the present invention, the laser has an output in the range of 3 to 6.5 W, and may be irradiated at a frequency in the range of 800 to 1600 kHz.

Further, according to an embodiment of the present invention, the laser may have a scanning rate of 0.3 m / s to 0.6 m / s.

According to an embodiment of the present invention made as described above, by forming a region having an illuminance value of nanometer to micrometer on the surface to suppress the proliferation of smooth muscle cells, surface modification to promote the proliferation of endothelial cells Stents can be provided.

In addition, the present invention has an effect of effectively suppressing thrombosis and restenosis problems after stent treatment by optimizing the shape and mobility characteristics of smooth muscle cells and endothelial cells using the surface-modified stent.

Of course, the scope of the present invention is not limited by these effects.

1 is a schematic view showing a surface-modified stent according to an embodiment of the present invention.
FIG. 2 is a scanning electron microscope (SEM) and atomic force microscope (AFM) photograph showing a surface according to the roughness value of a surface-modified stent according to an embodiment of the present invention.
FIG. 3 is a scanning electron microscope (SEM) photograph showing a surface of a surface-modified stent in which an area where roughness is formed, forming a pattern, according to an embodiment of the present invention.
Figure 4 is a flow chart showing a method of manufacturing a surface-modified stent according to an embodiment of the present invention.
5 is a schematic view showing a process in which a laser is irradiated to a specimen according to an embodiment of the present invention.
6 is a graph showing an X-ray diffraction (XRD) pattern according to a pulse width and output of a laser irradiated to a stent according to an embodiment of the present invention.
7 is a scanning electron microscope (SEM) photograph showing the surface roughness of a specimen according to Examples and Comparative Examples of the present invention.
8 is an atomic force microscope (AFM) photograph showing the surface roughness of a specimen according to Examples and Comparative Examples of the present invention.
9 is a graph showing the surface properties of a specimen according to Examples and Comparative Examples of the present invention.
10 and 11 are fluorescence image photographs showing cells cultured in specimens according to Examples and Comparative Examples of the present invention.
12 and 13 are graphs showing the degree of proliferation of cells cultured in specimens according to Examples and Comparative Examples of the present invention.
14 and 15 are fluorescence images and graphs showing the results of vascular endothelialization experiments of HUVEC cells in specimens according to Examples and Comparative Examples of the present invention.
16 and 17 are fluorescence images and graphs showing the results of vascular endothelialization of hAoSM cells in specimens according to Examples and Comparative Examples of the present invention.
18 to 20 are photographs showing the results of the mobility test of cells cultured in specimens according to Examples and Comparative Examples of the present invention.
21 is a scanning electron microscope (SEM) and an atomic force microscope (AFM) photograph showing a surface of a stent having various surface roughness values according to embodiments of the present invention.
22 is a photograph showing changes in surface morphology of HUVEC cells and SMC cells according to surface roughness values of stents according to embodiments of the present invention.

For a detailed description of the present invention, which will be described later, reference is made to the accompanying drawings that illustrate, by way of example, specific embodiments in which the invention may be practiced. These examples are described in detail enough to enable those skilled in the art to practice the present invention. It should be understood that the various embodiments of the present invention are different, but need not be mutually exclusive. For example, certain shapes, structures, and properties described herein may be implemented in other embodiments without departing from the spirit and scope of the invention in relation to one embodiment. In addition, it should be understood that the location or placement of individual components within each disclosed embodiment can be changed without departing from the spirit and scope of the invention. Therefore, the following detailed description is not intended to be taken in a limiting sense, and the scope of the present invention, if appropriately described, is limited only by the appended claims, along with all ranges equivalent to those claimed. In the drawings, similar reference numerals refer to the same or similar functions across various aspects, and length, area, thickness, and the like may be exaggerated for convenience.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings in order to enable those skilled in the art to easily implement the present invention.

1 is a schematic diagram showing a surface-modified stent 100 according to an embodiment of the present invention.

According to an embodiment of the present invention, the surface-modified stent 100 includes a metal alloy for a stent, and includes an area 150 in which roughness is formed on at least a portion of the surface 110. Can be.

The surface-modified stent 100 is an artifact that is inserted into blood vessels of the human body to facilitate circulation of blood. Therefore, the surface-modified stent 100 should be manufactured using a material harmless to the human body. Accordingly, the surface-modified stent 100 of the present invention may include any one of Nitinol (NiTi), Cobalt Chromiun (CoCr), or stainless steel (SUS) as a metal alloy for stents.

For example, Nitinol is an alloy in which nickel (Ni) and titanium (Ti) are mixed, and has human-compatible properties. In addition, reversible conversion between the austenite phase and the martensite phase is possible, and thus it has excellent properties for manufacturing in a stent-like structure. In addition, in the case of cobalt chrome (CoCr), it is a metal alloy suitable for the human body and can be used as a material for stents inserted into blood vessels.

Meanwhile, the surface-modified stent 100 may include an area 150 in which roughness is formed on at least a portion of the surface 110. When a conventional stent is inserted into the human body, various cells are adsorbed and grown on the stent, thereby causing side effects of vascular restenosis.

On the other hand, the surface-modified stent 100 of the present invention has an effect of promoting the growth of specific cells and inhibiting the growth of other cells by controlling the adsorption and proliferation rate of cells, including the region 150 where the roughness is formed. . In particular, on the region 150 where the roughness is formed, it is preferable that the migration rate of vascular endothelial cells is higher than that of smooth muscle cells. Due to this, the movement of the vascular endothelial cells is easy, but by forming the roughness so that the movement of smooth muscle cells is difficult, only the vascular endothelial cells can be efficiently proliferated around the stent.

At this time, according to an embodiment of the present invention, the surface 110 of the surface-modified stent 100 may include an area 150 in which roughness is formed in an area of 50% or more.

The surface-modified stent 100 may have roughness formed on the entire surface 110, or roughness may be formed only in a partial region. This is because when an illuminance is formed only in an area of 50% or less of the surface 110, an effect of suppressing the proliferation of specific cells, for example, smooth muscle cells, may be insufficient. Therefore, the surface-modified stent 100 may have roughness formed in a region of 50% or more, preferably 80% or more, of the surface 110.

In addition, according to an embodiment of the present invention, the roughness of the surface-modified stent 100 may have a value in the range of 35 nm Ra to 860 nm Ra, preferably the roughness is 200 nm Ra to 860 nm Ra It can have a value.

FIG. 2 is a scanning electron microscope (SEM) and atomic force microscope (AFM) photograph showing a surface according to the roughness value of a surface-modified stent according to an embodiment of the present invention.

Referring to FIG. 2, the surface-modified stent 100 may form regions 150 having various ranges of illuminance values on the surface 110. At this time, by varying the series of process conditions for forming the roughness, the value of the roughness formed on the surface 110 can be adjusted. The range of illuminance values may have a value in nanometers to micrometers. In order to effectively promote the proliferation of specific cells and maximize the effect of inhibiting the proliferation of other specific cells, the roughness value of the surface 110 may preferably have a value in the range of 200 nm Ra to 840 nm Ra.

In addition, according to an embodiment of the present invention, at least one region of the illuminance-formed region 150 may be formed in a direction spaced apart from each other with a certain width to form a repeated pattern.

FIG. 3 is a scanning electron microscope (SEM) photograph showing the surface of the surface-modified stent 100 in which the roughness-formed region 150 according to an embodiment of the present invention forms a pattern.

The surface-modified stent 100 may have roughness only in a portion of the surface 110. At this time, the region 150 where the roughness is formed is formed to have a specific width in one direction of the surface 110, and may be formed with the same width as a certain distance from the region 150 where the roughness is formed. The region 150 in which such roughness is formed may be repeated to form a specific pattern on the surface 110 of the surface-modified stent 100.

When the region 150 where the roughness is formed is formed to have a pattern, the surface 110 of the surface-modified stent 100 repeats the region 150 where the roughness is formed and the smooth region where no roughness is formed. In this way, when a pattern is formed by forming an illuminance in a portion of the surface 110, it is possible to maximize the effect of promoting the proliferation of specific cells or inhibiting the proliferation of other specific cells.

In the case of a specific cell, the cell must first be adsorbed to the corresponding region for proliferation. At this time, when the roughness is formed on the surface and has a rough protrusion-like surface, the area where specific cells can be adsorbed for proliferation is narrowed. Only cells with these characteristics can selectively inhibit proliferation. Particularly, when a pattern is formed at regular intervals between regions where roughness is formed, an effect of suppressing cell proliferation can be improved.

Next, with reference to Figures 4 to 6, a method of manufacturing a surface-modified stent according to an embodiment of the present invention will be described.

4 is a flow chart showing a method of manufacturing a surface-modified stent according to an embodiment of the present invention, and FIG. 5 is a schematic view showing a process in which a laser is irradiated to a specimen according to an embodiment of the present invention.

According to FIG. 4, the method of manufacturing the surface-modified stent 100 (S100) includes preparing a stent 10 including a metal alloy (S110) and nanoseconds on at least a portion of the stent 10 surface 110 It may include the step (S120) of irradiating the laser 500 having a laser pulse width of nano second) at least once, thereby forming roughness on at least a portion of the surface 110 of the stent 10.

In the manufacturing method of the surface-modified stent 100 (S100), a stent 10 including a metal alloy is first prepared (S110). At this time, the stent 10 does not necessarily have to have the shape of the surface-modified stent 100 disclosed in FIG. 1, and may be a shape that can be typically obtained in the roughness forming step during manufacture of the stent. For example, the cross-section may be in the shape of a square specimen or a cylindrical shape, and the present invention is not limited thereto.

Next, as shown in FIG. 5, a sample of the stent 10 including the metal alloy is prepared on a stage to which the laser 500 is irradiated. Then, the laser 500 having a nanosecond laser pulse width is irradiated on at least a portion of the surface 110 of the stent 10 at least once.

On the other hand, according to an embodiment of the present invention, the laser 500 has an output in the range of 3 to 6.5 W, and can be irradiated at a frequency in the range of 800 to 1600 kHz, and a scanning rate of 0.3 m / s To 0.6 m / s.

6 is a graph showing an X-ray diffraction (XRD) pattern according to the output and pulse width of the laser 500 irradiated to the stent 10 according to an embodiment of the present invention. At this time, as an example, the metal alloy for stents was patterned using Nitinol (NiTi). FIG. 6 (a) shows the surface 110 of the stent 10 on which the laser 500 is not irradiated, and FIG. 6 (b) shows the laser 500 irradiated on the surface 110 of the stent 10. The surface 110 when the output is 4 W and the frequency is 800 kHz, and FIG. 6 (c) shows the surface 110 when the output is 6.51 W and the frequency is 1600 kHz.

Referring to (a) of FIG. 6, it can be seen that the Nitinol alloy in which the laser 500 was not irradiated to the surface 110 shows only nickel (Ni) and titanium (Ti) peaks in the XRD pattern. On the other hand, referring to (b) and (c) of FIG. 6, when the laser 500 is irradiated to the surface 110, oxygen (O) contained in the titanium oxide layer due to oxidation of titanium by the laser 500 ) It can be seen that the peak appears.

At this time, referring to (c) of FIG. 6, when the output and frequency of the laser 500 irradiated on the surface 110 is too large, a large numerical illuminance may be formed on the surface 110, but X-ray The carbon (C) component appears in the diffraction pattern. When the stent inserted in the human body contains a carbon component, it may affect the characteristics of the stent, such as human body suitability and promoting cell proliferation. Therefore, in order to form the roughness on the surface 110, it is necessary to irradiate the laser 500 having an appropriate output value to form the roughness without containing impurities in the stent 10 component. Preferably, the laser 500 is irradiated with a power of 4 W and a frequency of 800 kHz, and the scanning rate may be 0.5 m / s.

In addition, according to an embodiment of the present invention, in the step of forming an illuminance (S120), the laser 500 is spaced apart from each other with a certain width on the surface 110 of the stent 10, and irradiated in one direction, the surface ( A repeated pattern may be formed in 110).

The surface-modified stent 100 of the present invention may include an area 150 in which roughness is formed in the entire area of the surface 110, but roughness may be formed in some areas to have a pattern. That is, when irradiating the laser 500, the area where the laser 500 is irradiated from the surface 110 of the stent 10 is spaced apart from each other, thereby forming an area of roughness on the surface 110 of the stent 10 ( 150).

And. The laser 500 is irradiated repeatedly on the irradiated area of the laser 500 one or more times to form roughness on at least a portion of the surface 110 of the stent 10 and manufacture the surface-modified stent 100.

Since the laser 500 irradiates by adjusting the output value so that the stent 10 is not carbonized, the illuminance value of the surface 110 may be adjusted by irradiating one or more times. At this time, according to an embodiment of the present invention, in the step of forming the illuminance (S120), the value of the illuminance may increase as the laser 500 is irradiated repeatedly.

When the laser 500 is irradiated once, the effect of suppressing the proliferation of specific cells may be insufficient because the illuminance value of the surface 110 is low. Accordingly, by irradiating the laser 500 repeatedly with the irradiated region one or more times, it is possible to form an illuminance having a desired value in the range of the surface 110. According to an embodiment of the present invention, in the step of forming an illuminance (S120), the laser 500 may be irradiated once to 32 times to form an illuminance, and preferably, the laser 500 is irradiated 16 times Surface-modified stent 100 may be prepared.

As described above, the surface-modified stent of the present invention can form a pattern having a roughness value in nanometers to micrometers on the surface to suppress the proliferation of smooth muscle cells and promote the proliferation of endothelial cells. In addition, it is possible to manufacture a surface-modified stent to maximize the characteristics of the stent by adjusting the output, frequency, and irradiated area of the laser irradiating the surface of the stent.

Hereinafter, embodiments will be described to help understanding of the present invention. However, the following examples are only to aid the understanding of the present invention, and the embodiments of the present invention are not limited to the following examples.

Example

7 to 9, a surface-modified stent according to an embodiment and a comparative example of the present invention will be described.

First, a sample of Nitinol (NiTi) alloy used as a stent material of the present invention is prepared. In NiTi, an alloy having 55% by weight of nickel (Ni) and 45% by weight of titanium (Ti) is prepared as a specimen. Then, the laser is irradiated to form a surface roughness. The laser used at this time is a Ytterbium pulsed fiber laser, the output is 4 W, the frequency is 800 kHz, the laser pulse width is 4 ns, and the wavelength is 1064 nm. The size of the laser beam was 35 µm, and the scanning speed was fixed at 0.5 m / s to irradiate the laser.

Example 1: Preparation of specimens with nanometer surface roughness (Nano-Ra)

The entire surface of the prepared NiTi specimen is irradiated with a laser. At this time, the pulse overlap ratio (pulse overlap ratio) is 60%, and the laser is irradiated only once. Nano-Ra (hereinafter, Example 1) having a surface roughness of nanometers in all regions of the specimen surface is prepared.

Example 2: Preparation of specimens with micrometer surface roughness (Micro-Ra)

A specimen was prepared in the same manner as in Example 1, but the laser was irradiated repeatedly 16 times. Micro-Ra (hereinafter, Example 2) having a surface roughness of micrometer in all regions of the specimen surface is prepared.

Example 3: Preparation of specimens with nanometer section surface roughness (Periodic-nRa)

The surface of the prepared NiTi specimen is irradiated with a laser to form a pattern in which a surface roughness is formed. The laser is irradiated in one direction so as to have a certain width, and the laser is irradiated at a predetermined interval to the irradiated area to form a pattern of roughness formed on the surface of the specimen. The laser is irradiated such that the width of the region where the roughness is formed and the distance between the other regions are 30 µm each. At this time, the pulse overlap ratio (pulse overlap ration) is -100%, and the laser is irradiated repeatedly 4 times. Periodic-nRa (hereinafter, Example 3), in which surface roughnes are nanometers, is prepared in a specific region where a pattern is formed on a specimen surface.

Example 4: Preparation of specimen with micrometer section surface roughness (Periodic-μRa)

A specimen was prepared in the same manner as in Example 3, but the laser was irradiated repeatedly 16 times. Periodic-μRa (hereinafter, Example 4) having a surface roughness in micrometers in a specific region where a pattern is formed on a specimen surface is prepared.

Comparative Example 1: Preparation of untreated specimen (Smooth)

A specimen in a state (Pristine) without laser irradiation on the prepared NiTi alloy base material is prepared, and this is defined as Smooth (Cont.) (Hereinafter, Comparative Example 1).

7 is a scanning electron microscope (SEM) photograph showing the surface roughness of a specimen according to Examples and Comparative Examples of the present invention. 7 (a), (b), (c), (d), and (e) are SEM photographs showing surfaces of Comparative Example 1 and Examples 1 to 4 specimens, respectively.

Referring to Figure 7, it can be seen that the specimen of Comparative Example 1 is smooth without the formation of roughness on the surface. In addition, it can be seen that the specimens of Examples 1 to 4 had different surface roughness depending on the number of times the laser was repeatedly irradiated. In particular, in Examples 3 and 4, there is a certain distance between the regions where the roughness is formed, so that a pattern is formed on the surface of the specimen.

8 is an atomic force microscope (AFM) photograph showing the surface roughness of a specimen according to Examples and Comparative Examples of the present invention. 8, it can be seen that the specimens have different surface roughness values. Comparative Examples 1 and Examples 1 to 4 have surface roughness values of 5.87 ± 1.04 nm Ra, 35.33 ± 10.04 nm Ra, 842.60 ± 71.33 nm Ra, 80.20 ± 23.06 nm Ra, and 839.60 ± 94.75 nm Ra, respectively.

9 is a graph showing the surface properties of a specimen according to Examples and Comparative Examples of the present invention.

FIG. 9 (a) shows X-ray diffraction patterns of Comparative Example 1, Examples 1 and 2, and FIG. 9 (b) shows a contact angle with respect to water of the specimen. To, Figure 11 (c) is a graph showing the degree of protein adsorption to the specimen.

9 (a) to 9 (c), it can be seen that the surface properties of the specimen change as the surface roughness is formed by irradiating the laser. Particularly, in the case of Example 2 having the largest surface roughness value, it can be seen that the contact angle with respect to water is greater than 100 degrees (shown in FIG. 9 (b)). And, it can be seen that the degree of adsorption to the protein is the lowest (shown in Fig. 9 (c)). This means that when a stent is inserted into the human body, a specific protein can be adsorbed and inhibit the growth or migration and spread.

Hereinafter, with reference to FIGS. 10 to 22, the experiments of proliferation and mobility of smooth muscle cells, vascular endothelial cells and muscle cells, will be described using the specimens of Examples 1 to 4 and Comparative Example 1. In order to test the response of cells to the specimens of Examples 1 to 4 and Comparative Example 1, the following experiment was performed using HUVEC as vascular endothelial cells and hAoSM as smooth muscle cells.

Experimental Example 1: Cell response experiment according to surface roughness

When the vascular endothelial cells HUVEC and smooth muscle cells hAoSM were cultured in the specimens of Examples 1 to 4 and Comparative Example 1, responses to cell adhesion, morphology, and proliferation were tested. To cultivate the cells and confirm their reaction, a fluorescence image sensor was used. Fluorescence images of F-actin, Anti-Pax and Anti-BrdU are shown in FIG. 12.

10 and 11 are fluorescence image photographs showing cells cultured in specimens according to Examples and Comparative Examples of the present invention, and FIGS. 12 and 13 are graphs showing the degree of proliferation of cultured cells.

FIG. 10 is a fluorescence image photograph of HUVEC cells and FIG. 11 is hAoSM cells. Referring to Figure 10, in the case of HUVEC vascular endothelial cells, it can be seen that in Examples 1 to 4 and Comparative Example 1 specimens are all well attached and maintained in shape, and proliferation is good. This means that HUVEC is not significantly affected by the surface roughness of the specimen.

On the other hand, referring to Figure 11, in the case of hAoSM, a smooth muscle cell, it can be seen that the shape of the cell changes according to the surface roughness of the specimen. In particular, in the specimens having surface roughness in the micrometer unit of Examples 2 and 4, the morphology of hAoSM cells was changed to a small or elongated shape, and it can be seen that the focal adhesion region decreased. In addition, when looking at BrdU measurement, it can be seen that proliferation is suppressed. When the cells were cultured for 5 days, it was confirmed that the number of hAoSM cells cultured in Examples 2 and 4 was small compared to Examples 1, 3 and Comparative Example 1. This means that the proliferation is suppressed because smooth muscle cells cannot adsorb onto the surface having a certain level of roughness or higher.

12 and 13, HUVEC cells, vascular endothelial cells, have a constant BrdU value regardless of the surface roughness of the specimen. On the other hand, it can be seen that the hAoSM cells, which are smooth muscle cells, have significantly lower BrdU values in the specimens of Examples 2 and 4.

In other words, as the surface roughness of the stent increases, preferably, the surface roughness of the micrometer unit can suppress the proliferation of smooth muscle cells without affecting the proliferation of vascular endothelial cells. Therefore, the surface-modified stent of the present invention has an effect of selectively suppressing cell proliferation by controlling surface roughness.

Experimental Example 2: Vascular endothelialization experiment according to surface roughness

Cells were cultured in the same manner as in Experimental Example 1, and vascular endothelialization experiments were performed to analyze the function of the cells. In order to confirm the vascular endothelialization of cells cultured in each specimen, genes related to endothelialization were analyzed.

14 and 15 are fluorescence images and graphs showing the results of vascular endothelialization experiments of HUVEC cells in specimens according to Examples and Comparative Examples of the present invention. In order to confirm vascular endothelialization of HUVEC cells, CD31 and vWF genes were analyzed by fluorescence images, and CD31, vWF, Tie-2 and VE-Cadherin genes were analyzed to analyze the number of expressed genes.

Referring to FIG. 14, it can be seen that in the case of HUVEC cells, vascular endotheliation occurs well as the surface roughness increases. That is, it can be seen that the fluorescence of the CD31 and vWF genes of HUVEC cells appears in the specimens of Examples 2 and 4 having surface roughness in micrometers.

And, referring to (a) and (b) of FIG. 15, in the specimens of Examples 2 to 4, genes related to vascular endothelialization according to HUVEC culture (CD31, vWF, Tie-2 and VE-Cadherin) It can be seen that it has a significantly high value.

It can be seen that, unlike the Experimental Example 1, as the surface roughness increased, vascular endothelialization of HUVEC cells was promoted. In other words, the formation of the surface roughness did not affect the morphological changes of the cells, but it means that the functions of the cells were affected.

Meanwhile, FIGS. 16 and 17 are fluorescence images and graphs showing the results of vascular endothelialization experiments of hAoSM cells in specimens according to Examples and Comparative Examples of the present invention. To confirm the proliferation of hAoSM cells, muscle cell markers were analyzed using alpha-SMA, SM-MHCs, and fibrosis markers MMP-14 and Collagen I.

Referring to FIG. 16, it can be seen that the hAoSM cells had weak anti-alpha-SMA and anti-MHC fluorescence images in the specimens of Examples 2 and 4 having large surface roughness. And, referring to (a) and (b) of FIG. 17, in Examples 2 and 4, the expression levels of alpha-SMA and SM-MHCs are high, and the expression levels of MMP-14 and Collagen I are low. This means that hAoSM cells, which are smooth muscle cells, do not become fibrous on the surface of the specimen and maintain the original characteristics of muscle cells.

That is, according to Experimental Example 2, the higher the surface roughness of the surface-modified stent, the vascular endothelialization of vascular endothelial cells is promoted, and fibrosis of smooth muscle cells as muscle cells can be suppressed. This means that it is possible to solve the problem of restenosis or vascular endothelial cell growth that may occur when the stent is inserted into the human body.

Experimental Example 3: Cell mobility experiment according to surface roughness

Cells were cultured in the same manner as in Experimental Example 1, and cell mobility experiments were performed. After culturing the cells except for the circular region with a diameter of 5 mm in each specimen, the number of cells moved to the circular region after 3 days was observed.

18 to 20 are photographs showing the results of the mobility test of cells cultured in specimens according to Examples and Comparative Examples of the present invention.

18 (a) and (b) are the results of the mobility of HUVEC cells, vascular endothelial cells. It can be seen that fluorescence does not appear because no cells are present in a circular region indicated by a white dotted line at the time of 0 hours, which is the initial period of culture. It can be seen that after 3 days, HUVEC cells migrate to the region and fluorescence appears. In the case of Comparative Example 1, it can be seen that after 3 days, about 60% of the black color was occupied in the circular region. It can be seen that the black portion (the region where no cells exist) in the circular region is smaller than the initial culture. In particular, in the case of Example 4, it can be seen that a large number of HUVEC cells migrated.

19 (a) and (b) are the results of the mobility of hAoSM cells that are smooth muscle cells. Basically, the mobility of smooth muscle cells, which are muscle cells, is higher than that of vascular endothelial cells. Referring to (a) of FIG. 17, it can be seen that in the case of the comparative example 1 specimen, hAoSM cells occupy 100% of the circular region after 3 days. The specimens of Examples 1 and 3 can also be seen that almost 100% of the cells occupy the area. On the other hand, in the specimens of Examples 2 and 4, the mobility of hAoSM cells was suppressed, and it appeared that the region did not occupy 100% after 3 days.

That is, it can be seen that the mobility of HUVEC, an vascular endothelial cell, is improved and the mobility of hAoSM, a smooth muscle cell, is suppressed due to the formation of surface roughness.

Meanwhile, FIG. 20 is a photograph showing the results of the mobility test of the cell mobility test control according to the comparative example of the present invention. Cyto D drug applied to an actual stent was introduced into the region and the mobility of vascular endothelial cells and smooth muscle cells was observed. It can be seen that both cells did not migrate to the region by Cyto D. That is, although cyto D is effective in inhibiting the movement of smooth muscle cells, vascular endothelial cells requiring movement also have a problem of inhibiting movement.

Experimental Example 4: Experiment of cell surface morphology change according to surface roughness

The surface morphology changes of vascular endothelial cells and smooth muscle cells according to the surface roughness of the surface-modified stent were tested. FIG. 21 is a scanning electron microscope (SEM) and atomic force microscope (AFM) photograph showing the surface of a stent having various surface roughness values according to embodiments of the present invention, and FIG. 22 is a stent A photograph showing the surface morphology change of HUVEC cells and SMC cells according to the surface roughness values of.

First, as shown in FIG. 21, specimens having various surface roughness values are prepared. The surface roughness value of the specimen ranged from 0.082 μm Ra to 0.835 μm Ra. Then, vascular endothelial cells, HUVEC, and smooth muscle cells, SMC, were cultured in each specimen, and surface morphology changes were tested. The results are shown in Figure 22.

Referring to FIG. 22, in the case of HUVEC, although the surface morphology change is not large according to the change in the roughness value of the stent surface, it can be seen that in the case of SMC, the cell turns into an elongated shape when the surface roughness value is about 0.200 μm Ra or more. .

This is because, on the surface where the stent roughness is formed, formation of a focal adhesion cluster, which is an essential process for SMC cell adhesion, is prevented. That is, as the surface roughness is 0.200 µm Ra or more, the adhesion force decreases as the formation of focal adhesion regions of smooth muscle cells SMC is impeded. As a result, the surface roughness is aligned on a smooth surface on which no surface roughness is formed, and thus has an elongated shape. That is, by forming roughness on the surface of the stent, there is an effect of preventing the growth of specific cells.

According to the results of Experimental Examples 1 to 4 above, the stents formed with the surface roughness of Examples 1 to 4 promote the adsorption and proliferation of HUVECs, which are vascular endothelial cells, and suppress the smooth muscle cells, hAoSM cells. In particular, it can be seen that the effect is further improved in Examples 2 and 4 in which the surface roughness value is in micrometers. This is because the growth of cells was suppressed because the area where smooth muscle cells can be adsorbed by the roughness formed on the stent surface was reduced.

Accordingly, the surface-modified stent according to an embodiment of the present invention may form a pattern having a roughness value in nanometer to micrometer on the surface to suppress proliferation of smooth muscle cells and promote proliferation of endothelial cells. . In addition, by using the surface-modified stent, the shape and mobility characteristics of smooth muscle cells and endothelial cells are optimized to effectively suppress thrombus and restenosis problems after the stent procedure.

The present invention has been illustrated and described with reference to preferred embodiments, as described above, but is not limited to the above embodiments, and can be varied by those skilled in the art to which the present invention pertains without departing from the spirit of the present invention. Modifications and modifications are possible. Such modifications and variations are to be considered as falling within the scope of the invention and appended claims.

10: stent
100: surface modified stent
110: surface
150: area where roughness was formed

Claims (12)

It contains a metal alloy for stents,
It includes an area where roughness is formed on at least a part of the surface,
The region where the roughness is formed has at least one region having a certain width and spaced apart from the other regions to form a repeating pattern by being formed in one direction,
Surface modified stent. According to claim 1,
The surface is a surface-modified stent comprising an area in which the roughness is formed in an area of 50% or more. delete According to claim 1,
The roughness has a range value of 35 nm Ra to 840 nm Ra, surface modified stent. The method of claim 4,
The roughness is a surface-modified stent having a value in the range of 200 nm Ra to 840 nm Ra. According to claim 1,
The metal alloy is Nitinol (Nitinol, NiTi), cobalt chrome (Cobalt Chromiun, CoCr) or stainless steel (Stainless steel, SUS) any one of, surface-modified stent. Preparing a stent comprising a metal alloy; And
Irradiating a laser having a nanosecond laser pulse width on at least a portion of the stent surface at least once, thereby forming roughness on at least a portion of the stent surface;
Including,
In the step of forming the roughness, the laser is irradiated in a direction spaced apart from the other roughness forming regions with a certain width on the surface to form a repeated pattern on the surface, thereby producing a surface-modified stent. Way. delete The method of claim 7,
In the step of forming the roughness, the method of manufacturing a surface-modified stent increases by repeatedly irradiating the laser. The method of claim 9,
In the step of forming the roughness, the laser is irradiated once to 32 times to form the roughness, a method of manufacturing a surface-modified stent. The method of claim 7,
The laser has a power in the range of 3 to 6.5 W, and is irradiated at a frequency in the range of 800 to 1600 kHz, a method of manufacturing a surface modified stent. The method of claim 9,
The laser scanning rate (Scanning rate) has a range of 0.3 m / s to 0.6 m / s, the method of manufacturing a surface-modified stent.

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