KR102532990B1 - A manufacturing method for medical stent using laser - Google Patents

Abstract

The present invention, a pattern formation step of forming a separation prevention groove on the surface of the stent using a laser; a second pattern forming step of forming microholes for drug release symmetrically at predetermined intervals on the surface where the separation prevention grooves are formed using the laser; and coating the inside of the microhole with a drug.
Through this, the medical stent can be prevented from being displaced by improving adhesion to the human body insertion portion, and enables uniform drug coating and drug release time control.

Description

A manufacturing method for medical stent using laser}

The present invention relates to a medical stent, and more particularly, to a method for manufacturing a medical stent that enables adhesion to an insertion portion and uniform drug release through surface treatment of the medical stent using a laser.

In general, a medical stent is a medical device used to expand the diameter of a blood vessel by inserting it into the inside of the blood vessel when the diameter of the blood vessel is narrowed due to various diseases occurring in the human body and the blood circulation does not occur smoothly. says These stents can be inserted into the human body through various surgical methods, and are mainly inserted into blood vessels such as the heart, aorta, and cerebrovascular vessels together with a balloon catheter. This is a method of inserting a balloon catheter into a blood vessel, inflating the balloon, and expanding the passage of the blood vessel as the balloon is inflated.

Existing stents inflate outward as the balloon expands so that they expand as much as the diameter of the passageway of the original blood vessel. For this purpose, looking at the generation by material, 1st generation stainless steel, 2nd generation cobalt chrome and platinum chrome, and 3rd generation biodegradable material is changed.

In addition, stents have been developed from bare metal stents (BMS) to drug eluting stents (DES). In DES, a drug for preventing restenosis of a blood vessel is coated on the surface of the stent so that the drug can be supplied into the blood vessel. Here, as the drug, a drug having a function of inhibiting the proliferation of new endothelial cells by reducing cell proliferation is used.

However, late stage thrombosis, one of the aftereffects of stents, was caused by neointimal hyperplasia and plaque rupture in the case of BMS, and positional displacement is a problem in the case of DES.

As a prior art, Korean Patent Registration No. 10-1649305 discloses that, in order to prevent restenosis of blood vessels by the DES method, the surface of the stent is anodized and then the anodized surface is removed to form irregularities on the surface, and the anodized surface is It is detached and prevents it from moving around inside the blood vessels.

However, the prior art is not suitable for the current third-generation biodegradable stent material due to the possibility of remaining in the human body as a drug and chemical coating method applied to the metal stent and difficulty in later removal. In addition, there are problems such as environmental pollution during anodization and additional costs and time required for processes such as a separate additional process for removing metal oxides.

On the other hand, in recent years, due to the development of pulse lasers, the use of various lasers such as cutting, welding, patterning, and surface treatment is increasing while minimizing material deformation. It is possible to improve problems such as carbonization, burr, and material damage by utilizing its characteristics, and it shows a remarkable superiority in processing speed and precision, so there is a demand to apply it to medical stent manufacturing.

Korea Patent No. 10-0994543 Korea Patent No. 10-1649305

The present invention reflects the problems and needs as described above, and by using a laser to form a separation prevention groove and a microhole for drug release on the surface of the stent, it is possible to prevent positional deviation by improving adhesion to the human body insertion part. It is an object of the present invention to provide a method for manufacturing a medical stent capable of uniform drug coating and drug release time control.

To this end, the present invention, a first step of pattern formation to form a separation prevention groove on the surface of the stent using a laser; a second pattern forming step of forming microholes for drug release symmetrically at predetermined intervals on the surface where the separation prevention grooves are formed using the laser; and coating the inside of the microhole with a drug.

In addition, the material of the medical stent is characterized in that the biodegradable polymer material.

In addition, the laser is characterized in that a femtosecond-based laser having a pulse time of 10 ⁻¹⁵ /sec or less is used.

In addition, the anti-leave groove portion is characterized in that it has an angle of inclination direction in the opposite direction according to the direction of progression of the aneurysm or varicose veins in the range of -45 ° to +45 °.

In addition, it is characterized in that the drug release time is controlled by adjusting the depth of the microhole.

In addition, it is characterized in that the hydrophilicity is realized by adjusting the ratio of the width and depth of the microholes.

In addition, according to the direction of blood flow, a relatively large number of microholes are formed at the edge portion of the stent rather than at the center portion, and the number of microholes formed is uniformly formed vertically or horizontally symmetrically, so that uniform drug release is possible. do.

As described above, in the present invention, by using a laser to form a release prevention groove on the surface of a stent made of biodegradable polymer material, adhesion to the human body insertion portion is improved to prevent the possibility of separation after insertion into the human body. .

In addition, uniform drug coating is possible by forming microholes on the surface of the stent, and drug release amount and time can be controlled by adjusting the diameter and depth of the formed microholes.

1 is a perspective view showing the appearance of a laser processing apparatus for surface modification of a medical stent according to a preferred embodiment of the present invention;
2 is a functional block diagram showing the configuration of a laser processing device for surface modification of a medical stent;
3 is a view showing a laser beam output output process using a laser and an optical system in the laser processing device for surface modification of the medical stent of FIG. 2;
4 is a flow chart showing a manufacturing process of a laser-based drug-eluting surface-modified medical stent according to a preferred embodiment of the present invention;
5 is a view showing a medical stent manufactured through the medical stent manufacturing process of FIG. 4;
6 and 7 are views showing the separation prevention groove in the medical stent of FIG. 5 in more detail;
8 is a view showing an example of realizing hydrophilicity by adjusting the ratio of the width and depth of microholes in the medical stent of FIG. 5;
FIG. 9 is a diagram explaining a process of forming microholes in the medical stent of FIG. 5 considering the effect of the direction of blood flow.

Hereinafter, an apparatus and method for manufacturing a laser-based drug-eluting surface-modified medical stent according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

<Configuration diagram of laser processing device for surface modification of medical stent>

1 is a perspective view showing the appearance of a laser processing device for surface modification of a medical stent according to a preferred embodiment of the present invention, FIG. 2 is a functional block diagram showing the configuration of a laser processing device for surface modification of a medical stent, and FIG. It is a diagram showing the laser beam output output process using the laser and optical system in the laser processing device for surface modification of medical stent.

1 and 2, the laser processing device includes a control device 100, a memory unit 102, a user interface device 104, a laser controller 106, a laser 108 and , The optical system 110, the processing chamber 120, the position controller 122, the mechanism driving unit 124, and the 3D scanner 126 may be configured.

The control device 100 generally controls each part of the laser processing device for surface modification of the medical stent to perform surface treatment through micro-pattern processing when the medical stent is inserted into a blood vessel according to a preferred embodiment of the present invention. Through this, it is possible to increase the fixation force during endovascular insertion and to inject drugs into the surface-modified stent.

The memory unit 102 stores various information including the control program of the control device 100, and in particular, stores processing information for surface treatment such as forming a fine pattern of a medical stent according to a preferred embodiment of the present invention. do. The processing information is a first table for the depth of the micro-pattern shape and the micro-hole for improving the fixation force in the blood vessel at the insertion part of the medical stent, and the wavelength and intensity previously determined for laser processing according to the micro-pattern shape and the micro-hole It can be composed of a second table for. Here, the wavelength refers to the wavelength of the laser beam, and the intensity refers to the intensity of the laser beam. In addition, the processing information may further include a motor movement speed and the number of repetitions of processing.

The user interface device 104 is responsible for the interface between the user and the control device 100, and provides various types of information input by the user to the control device 100. In particular, the user inputs the shape of the micropattern (separation prevention groove, microhole) on the surface of the stent, depth information of the microhole, and material information about the material of the stent as the processing information through the user interface device 104. can do.

The laser controller 106 is a laser 108 to generate a laser beam for surface treatment processing for the micro-hole depth, the fine pattern of the micro-hole, and the anti-leave groove in the medical stent according to the position control information by the control device 100. to control

The laser 108 generates a laser beam of time, wavelength, and intensity according to the control of the laser controller 106 and radiates it to the outside. The laser beam may be a pulsed laser capable of increasing temporal convergence of energy in order to manufacture a medical stent having various micro-pattern structures and hole depths when a blood vessel is inserted.

In addition, it is preferable to use a laser having a short time width of femtosecond (10 ^-15 /sec) or less for the time of the pulse, reflecting the high precision and accuracy required for microprocessing in medical instruments will be.

The optical system 110 irradiates the laser beam of the laser 108 to the stent 128 in the processing chamber 120 to correspond to the shape of the stent 128 to form micropatterns and microholes on the surface of the stent 128. form

In this optical system 110, referring to FIG. 2, the laser 108 and the optical system 110 are controlled through the laser controller according to the optical system control information by the controller. That is, the laser beam output from the laser 108 is scanned and surface processed in the X-Y-Z-C direction on the stent 128 in the processing chamber 120 by the laser optical system 110). .

The processing chamber 120 accommodates the stent 128 to be processed, and corresponds to the processing information for surface treatment of the stent 128 (eg, the shape of a micropattern formed on the surface of the stent, the depth of a microhole, etc.) The laser beam is output while moving in more than 4 axes x, y, z, c to be processed. The x, y, and z denote three axes in the three-dimensional space, and c denotes a rotation axis.

The position controller 122 is composed of x, y, z, c 4-axis motors to move the processing chamber 120 in x, y, z, c 4-axis according to the position control information from the control device 100. Controls the driving of the mechanism driving unit 124 to be.

The 3D scanner 126 3D scans the stent 128 to be processed under the control of the control device 100 and provides the 3D scanned information to the control device 100 . Here, the control device 100 receives the 3D scan information and compares it with the processing information of the stent to be processed (eg, the shape of the micropattern of the anti-release groove, the depth of the microhole, etc.) to inform the user of the processing state of the stent It checks the current status and is used in the finishing process for final processing.

<Manufacturing process of laser-based drug-eluting surface-modified medical stent>

A process of manufacturing a medical stent using the above-described laser processing apparatus and a stent manufactured thereby will be described in detail with reference to FIGS. 4 to 8 .

4 is a flowchart showing a manufacturing process of a laser-based drug-eluting surface-modified medical stent according to a preferred embodiment of the present invention, and FIG. 5 is a view showing a medical stent manufactured through the manufacturing process of the medical stent of FIG. 4 .

Referring to FIGS. 4 and 5 , as a first step of pattern formation, a separation prevention groove 131 is formed on the surface of the stent 128 (S410).

At this time, the stent is generally a tubular mesh structure, but is not limited thereto, and various types of structures are possible. In addition, as a material of the stent 128, as a biodegradable polymer material, PLA (Poly Lactic Acid), PCL, PGA, etc. may be used, and PLA was used here.

In particular, PLA material may cause problems such as deviation from the treated position when used as a stent due to its low physical properties, etc. A plurality of lines are processed to form the anti-leave groove 131. At this time, the separation prevention groove 131 may form a surface roughness by forming an embossed protrusion or an intaglio groove, and through this, the roughness of the surface of the stent 128 is improved. Separation due to external forces such as blood flow can be prevented. In addition, the shape of the protrusion or groove of the separation prevention groove 131 is V-shaped (V-groove) based on the insertion direction of the human body, a lenticular type having two convex surfaces, or a sawtooth structure having a rectangular cross section. The shape is possible, and the shape of the protrusion can be all of the shape of a groove. can

Subsequently, as the second step of pattern formation, microholes 132 capable of time control are formed at predetermined intervals on the surface of the stent 128 (S420), and drugs are injected into the formed microholes 132 (S430) . At this time, the formation of the microhole 132 is a step of processing the shape for controlling the drug release time in the DES method, and the release time can be controlled by adjusting the diameter and depth of the microhole 132 formed on a plane basis, Formed symmetrically to enable uniform drug injection.

Hereinafter, the surface treatment process of the medical stent will be described in more detail using the laser processing apparatus of FIG. 2 with reference to FIGS. 6 to 9 .

6 and 7 are views showing the separation prevention groove in more detail in the medical stent of FIG. 5, and FIG. 8 is a hydrophilic property by adjusting the ratio of the width and depth of microholes in the medical stent of FIG. 5 FIG. 9 is a diagram illustrating a process of forming microholes in consideration of the effect of the direction of blood flow in the medical stent of FIG. 5 .

For example, the controller 100 of the laser processing device of FIG. 2 processes the material of the stent, the shape of the fine pattern of the anti-separation groove 131, the depth of the micro hole, etc. Guidance on entering information. Subsequently, according to the above guidance, the user may input the stent material for surface treatment of the stent, the shape of the micropattern of the anti-separation groove 131 and the depth of the microhole through the user interface device 104 .

Next, when the stent material, micro-pattern shape, and micro-hole depth information are input, the control device 100 sets a predetermined time, wavelength, and intensity corresponding to the input stent material, micro-pattern structure, and micro-hole depth information. is determined to generate laser emission information.

In addition, the control device 100 generates optical system control information and position control information for laser processing corresponding to the stent material, the micro-pattern structure, and the micro-hole depth information. This position control information is x, y, z, c 4-axis motor driving information, and the optical system control information is driving information for driving the mirror, scanner, etc. of the optical system 100 .

As described above, when laser emission information, position control information, and optical system control information are provided, the control device 100 drives the laser 108, the optical system 110, and the mechanism driving unit 124 to process the stent.

Thereafter, the control device 100 scans the primarily processed stent through the 3D scanner 126 according to the user's request. At this time, even after the first processing, the final processing for the stent is performed by repeating the processing process through feedback control.

Here, Table 1 describes the optimal embodiment by exemplifying the results of testing the time, wavelength, and strength corresponding to the stent material, micropattern structure, and microhole depth information obtained based on the experiment.

Table 1 shows the optimal embodiment for laser processing.

division optimum conditions laser femtosecond laser wavelength UV~IR band 800nm power energy 0.1W to 200W

Referring to Table 1, a short time width of femtosecond (10 ^-15 /sec) or less to improve the damage and carbonization of the material of the medical stent during laser processing and to process ultra-precision micropatterns on the surface of the stent A laser having , and the laser has an output of 0.1W or more and 200W or less for various patterns and microhole depth control. Therefore, according to the present invention, the wavelength and intensity of the laser beam corresponding to the stent material, the micro-pattern structure, and the micro-hole depth information are determined in advance, and the processing information is stored in the memory unit 102 . The processing information consists of a first table for the micro-pattern shape and micro-hole depth of the medical stent, and a second table for the time, wavelength, and intensity previously determined for precision processing according to the micro-pattern shape and micro-hole depth. . Here, the time is the laser beam output time, the wavelength refers to the wavelength of the laser beam, and the intensity refers to the intensity of the laser beam. In addition, the processing information may further include a motor movement speed and the number of repetitions of processing.

By applying a laser power range of 0.1W to 200W, it prevents material damage and carbonization during surface processing of biodegradable material stents such as PLA material, and prevents breakaway grooves such as V-shaped, lenticular, and sawtooth structures. It can be formed, Figure 6a illustrates a V-shaped groove (V-groove) as the departure prevention groove (131).

At this time, as shown in FIG. 6B , the separation preventing groove 131 may be more effective in preventing separation when inserted into the human body by controlling the shape of the groove to converge in the direction of blood flow.

That is, as shown in FIG. 7A, the anti-separation groove 131 is patterned by designating an inclination angle in the range of -45° to +45° with respect to the gravity direction according to the human body insertion site. For example, according to the direction of progression of aneurysms or varicose veins, the separation prevention groove 131 is angled in an oblique direction in the opposite direction to prevent stent detachment from the surgical position due to the use of biodegradable polymer materials, thereby increasing the stent detachment rate improvement can be made.

As shown in FIG. 7B, the surface pattern is processed by designating an inclination angle in the range of +45° in the opposite direction according to the direction of progression of the aneurysm to form an anti-separation groove. On the other hand, according to the direction of progression of varicose veins, it is possible to form anti-leave grooves by designating an inclination angle in the range of -45° in the opposite direction and processing the surface pattern. Through this, in order to prevent separation due to the flow of blood flow, the separation prevention groove may be formed by surface pattern processing such that the shape of the groove converges in the direction of the blood flow.

As shown in FIG. 7C, the drug release time can be controlled by adjusting the depth of the microhole 132 during laser processing, and the depth of the microhole 132 can be adjusted from 1 μm to A. Here, the depth A of the maximum microhole must be smaller than the thickness d of the stent (A<d), and the thickness d of the street is 10 μm to 200 μm.

In addition, the microhole 132 is a drug release hole in the stent, and in the case of the drug coated on the microhole 132, the drug is gradually released through blood flow friction. Since the drug release time also increases, it is in a proportional relationship with each other.

In addition, during laser processing, the laser power level is controlled within the range of 0.1W to 200W, and the higher the power level, the greater the depth of the microhole 132 can be adjusted, so that the drug release time can be controlled.

As shown in FIG. 8 , it can be confirmed that hydrophilicity is implemented by adjusting the ratio of the width and depth of microholes.

That is, in order to process microholes for drug release, if the ratio of the width and depth of the microholes is 1:1 or less, surface hydrophilicity can be realized. As such, when the surface of the microhole is hydrophilic, drug injection is easier and the duration of the drug is also increased.

As shown in FIG. 9 , the drug release time can be controlled by adjusting the depth of the micro hole according to the insertion position of the stent in the human body. That is, during micro-hole laser processing, the drug is released quickly in parts with many obstacles such as blood flow, and the depth and number of holes are adjusted in areas with less obstacles so that the drug is released more slowly. can

To this end, the number of microholes is relatively large and the depth of the microholes is relatively low so that the drug can be released quickly at the edge of the stent (a site with many obstacles such as blood flow) according to the direction of blood flow. On the other hand, the number of microholes is relatively small and the depth of the microholes is relatively high so that the drug is released more slowly in the center of the stent (a part where there are fewer obstacles such as blood flow).

The embodiments of the present invention described above are disclosed for illustrative purposes, and those skilled in the art will be able to make various modifications, changes, and additions within the spirit and scope of the present invention, and these modifications , changes and additions should be considered to fall within the scope of the claims.

100: control device
102: memory unit
104: user interface device
106: laser controller
108: laser
110: optical system
120: processing chamber
122: position controller
124: mechanism drive unit
126: 3D printer
128: medical stent
131: departure prevention groove
132: micro hole

Claims (7)

In the method for manufacturing a medical stent,
A first pattern formation step of forming a separation prevention groove on the surface of the stent using a laser;
a second pattern forming step of forming microholes for drug release symmetrically at predetermined intervals on the surface where the separation prevention grooves are formed using the laser; and
Including; coating the inside of the microhole with a drug,
A method for manufacturing a medical stent, characterized in that for controlling the drug release time by adjusting the depth of the microhole. According to claim 1,
The material of the medical stent is a medical stent manufacturing method, characterized in that the biodegradable polymer material. According to claim 1,
The laser is a medical stent manufacturing method characterized in that using a femtosecond-based laser with a pulse time of 10 ⁻¹⁵ /sec or less. According to claim 1,
The shape of the protrusion or groove of the separation prevention groove is V-groove based on the insertion direction of the human body, a lenticular type having two convex surfaces, or a sawtooth structure having a rectangular cross section Characterized in that any one is used A method for manufacturing a medical stent. According to claim 1,
The method of manufacturing a medical stent, characterized in that the separation prevention groove has an angle of inclination in the opposite direction according to the direction of progression of the aneurysm or varicose vein in the range of -45 ° to +45 °. According to claim 1,
A method for manufacturing a medical stent, characterized in that the drug duration is controlled by adjusting the ratio of the width and depth of the micro-hole. According to claim 1,
According to the direction of blood flow, a relatively large number of microholes are formed at the edge portion of the stent rather than at the center portion, and the number of microholes formed is uniformly formed vertically or horizontally symmetrically, so that uniform drug release is possible. Stent manufacturing method.

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