JP4740741B2 - Medical guide wire coated with carbon film - Google Patents

Description

The present invention relates to a medical insertion wire (medical guide wire).
Furthermore, the present invention has high lubricity, can be stably and smoothly advanced in the catheter and in living tissue such as a tubular tissue such as a blood vessel and a digestive tract, and has an appropriate rigidity and is easy to operate. Related to a medical guide wire.

  The medical guide wire is used as, for example, a treatment tool for guiding a treatment tool or the like to an affected part in the body, or is inserted through a living tissue such as a tubular tissue so that the distal end reaches the affected part. It is used as a treatment tool for performing the treatment.

  For example, a medical guide wire for treating coronary artery infarction has a spiral wire attached portion formed at the tip of a core wire and a spiral wire attached to the spiral attached portion. The helical wire attached portion is usually formed in a tapered shape, and the helical wire is formed by forming a wire, that is, a wire in a coil shape, and is called a guide wire.

  FIG. 1 shows the basic structure of a conventional guide wire.

  For example, a guide wire used for the treatment of coronary artery infarction is inserted into a catheter inserted into a blood vessel from a predetermined part of the human body with the attached portion at the top. This catheter is inserted into the human body so that the distal end opening is located in the vicinity of the affected part in the human body. The medical guide wire is retracted into the catheter, and the distal end of the medical guide wire further reaches the affected area from the distal end opening of the catheter. At this time, the distal end of the medical guide wire reaches the affected area, while the distal end of the medical guide wire is out of the human body.

  Next, the distal end of the medical guide wire is inserted into the treatment tool, and the treatment tool is advanced along the catheter through the medical layer through line to reach the affected part. By operating the treatment tool that reaches the affected area, appropriate treatment is performed with the treatment tool.

  The medical guide wire travels from the catheter insertion site to the vicinity of the affected part in the human body through the curved catheter while being in contact with the inner surface of the catheter. Therefore, if the sliding between the medical guide wire and the catheter is poor, the medical guide wire cannot smoothly travel through the catheter.

  Therefore, conventionally, a medical guide wire is usually made of a polytetrafluoroethylene (PTFE) coating film on the outer peripheral surface, thereby reducing the frictional resistance between the outer peripheral surface of the medical guide wire and the inner surface of the catheter. The guide wire is designed to travel smoothly through the catheter.

  Further, if the diameter of the medical guide wire is large, the spatial margin in the catheter becomes small and it becomes difficult to advance in the catheter. Therefore, the diameter of the medical guide wire must be a certain size or less. For this reason, when applying the PTFE coating film, the core wire of the medical guide wire to be coated with PTFE is designed to be thin in advance by the thickness of the PTFE coating film, and the PTFE coating film is formed on the core wire, The diameter of the medical guide wire is kept from becoming too large.

  On the other hand, if the core wire of the medical guide wire is made thin, the rigidity of the medical guide wire will be reduced and the waist will be weakened. The force applied to is not sufficiently transmitted to the tip portion, and the inconvenience such as inability to effectively treat the affected area occurs. Therefore, it is desirable to make the thickness of the PTFE coating film as thin as possible and make the diameter of the core wire as thick as possible.

  However, the PTFE coating film is highly wearable and must be formed thick at the initial stage, and it is technically difficult to reduce the thickness. Therefore, the diameter of the core wire of the medical guide wire to which the PTFE coating film is applied is inevitably small, and it is difficult to secure the waist strength of the medical guide wire sufficient to avoid the above-described disadvantages. It is.

  In addition, after the distal end portion of the medical guide wire comes out of the catheter from the distal end opening portion of the catheter, the distal end portion of the medical guide wire is in contact with the inner wall surface of the blood vessel toward the affected area through the blood. proceed. Accordingly, the distal end portion of the medical guide wire is required to have lubricity with the inner wall of the blood vessel and affinity with blood after coming out of the catheter.

  On the other hand, a medical guide wire provided with a DLC film has a DLC film whose wear resistance is smaller than that of a PTFE film, the lubricity of the DLC film is equal to or higher than that of a PTFE film, and a thin DLC film. The thickness of the DLC film can be made thinner than that of the PTFE film because it is technically possible to form the wire, and accordingly, the diameter of the core wire can be increased, and the medical guide It is possible to increase the strength of the waist of the wire.

  Here, DLC is an abbreviation for Diamond Like Carbon, which is a substance composed mainly of carbon atoms and containing a small amount of hydrogen atoms. Diamonds composed of carbon atoms have a diamond structure ( Graphite, which is composed of SP3) and is also composed of carbon atoms, is composed of a graphite structure (SP2), whereas DLC includes both SP3 and SP2 and partly bonds with hydrogen. Having an amorphous structure.

However, since the coated DLC film does not have sufficient resistance to welding to human tissues such as blood and the inner wall surface of blood vessels, there are many research examples regarding application to medical devices. As described above, the DLC film in the medical guide wire can contain fluorine, and if the DLC film contains fluorine, there is an advantage that the lubricity to the catheter and the living body can be further improved. In general, DLC containing fluorine having excellent antithrombogenicity is inferior in adhesion to a member, and therefore, an intermediate composed of silicon, silicon carbide, titanium oxide, titanium nitride, etc. between the member and the DLC film containing fluorine. A layer is provided to improve adhesion of the DLC film, or a DLC film containing fluorine is covered through a DLC film not containing fluorine.
As described above, the DLC film is a thin layer and has high hardness and wear resistance. However, when the coating film contains many SP3 bonds with respect to SP2, it receives stress due to strong cohesion in the coating. In some cases, the coating tends to peel off due to so-called interfacial fracture that breaks at the interface with the substrate.

Conventionally, it is publicly known (Patent Document 1) to coat a catheter guide wire surface with a DLC coating. In Patent Document 2, a radio frequency is used in an atmosphere containing a hydrocarbon-based gas with a substrate such as a medical wire as an anode. It is also known to provide a DLC film on a substrate by using plasma from a source.
Furthermore, in patent document 3, it is a medical guide wire characterized by having a core wire body and the DLC film formed in the surface, and this medical guide wire extends from the front-end | tip of a core wire body to a predetermined site | part. A spiral wire body attached portion, and a spiral wire body is attached to the spiral wire body attached portion, and the wire core has a hydrophilic substance as a functional group on a surface from a tip thereof to a predetermined portion. It has a hydrophilic coating that exists in combination. In addition, a silicon coating is formed between the core wire and the DLC coating formed on the surface, and the DLC coating is a medical guide wire containing fluorine and having a thickness of 0.3 to 7 μm. .

WO99 / 53988 ; JP 2000-64047 A ; JP 2001-238932 A

The conventional single-composition-coated guidewire has a problem in balance between hardness, elasticity, and slidability. When the distal end portion and the intermediate portion of the guide wire contained a large amount of SP3 component, the distal end portion was hard and elastic, and there was a high risk of destroying a blood vessel portion having a small curvature radius. Furthermore, the tip was hard and the possibility of peeling from the point of elasticity was high. On the other hand, if the tip part and the intermediate part contain a large amount of SP2 component, the slidability of the entire guide wire deteriorates during use, strain is concentrated on a part, and a route is selected so that the entire wire is intended. There were many problems in terms of control.
Further, it has been clarified that the DLC film containing fluorine improves the welding resistance to human tissues such as blood, muscles, blood vessels and the like as compared with the case of the carbon film not containing fluorine. For this reason, various measures have been taken such as providing an intermediate layer having an affinity for both of the substrates in contact with the DLC film. However, it is practically difficult to provide a multi-layer structure using various raw materials, and an extremely thin film is required from the viewpoint of applications, and it is likely to be expensive to achieve this. On the other hand, the DLC film containing a large amount of fluorine atoms improves the adhesion resistance to human tissues such as blood, muscles, blood vessels, etc., but the adhesion to the substrate due to the cohesive force of the carbon film containing fluorine. Not only is the coating easily peeled off due to interfacial fracture, but the hardness of the diamond-like carbon film is reduced, so that the wear resistance is inferior.

The present invention eliminates the drawbacks of the medical guide wire as described above, that is, forms a silicon film on the surface of the core wire body from the tip of the core wire body to a predetermined site, and includes DLC containing fluorine on the upper surface thereof. film lubrication is higher than medical挿痛line member formed with a smoothly can proceed within the tubular tissue in the catheter and blood vessel or the like, also has moderate rigidity, the operation is easy, namely, sliding An object of the present invention is to provide a medical guide wire having excellent dynamic characteristics .

This invention solves the said subject by having the following structures, and is as follows. The medical guide wire according to claim 1 of the present invention is a medical guide wire coated with a diamond-like carbon film, and the coating of the diamond-like carbon film is 5 to 30 mm from the tip of the medical guide wire. SP3 / SP2 ratio of the coating film is 0.01 or more and 0.2 or less in the wire tip portion that is in the range of 100 to 3000 mm from the tip portion, and SP3 / SP2 of the coating film is in the range of 100 to 3000 mm from the tip. The SP2 ratio is 0.2 or more.
The medical guide wire according to claim 2 is characterized in that the diamond-like carbon film has a thickness of 0.02 to 2 microns.

Medical guide wire of the present invention Shape of artificial blood vessel of guide wire sliding property evaluation test machine Comparison of sliding characteristics of medical guide wire of the present invention in experiment A (significant difference test) Comparison of sliding characteristics of guide wire coated with DLC of the present invention Comparison of sliding characteristics of medical guide wire of the present invention in B experiment (significant difference test)

In the medical guide wire of the present invention, the tip and middle portions of the wire are coated with a diamond-like carbon film composition, fine structure, particularly a DLC film having a different SP3 / SP2 ratio, and the guide wire body is coated with PTFE. SP between the core material and the coated carbon film
It has an area with a small 3 / SP2 ratio, has high lubricity, can stably and smoothly advance in a catheter and in a living tissue such as a tubular tissue such as a vascular digestive tract, and has an appropriate rigidity. Therefore, the medical guide wire is easy to operate.

Furthermore, the medical guide wire of the present invention is characterized in that the DLC coating is coated, and the SP3 / SP2 ratio within a depth of 0.1 microns from the coating surface is 0.01 or more and 10 or less.
In the medical covering member of the present invention, in a region where the depth from the coating surface is deeper than 0.1 micron, the lower the SP3 / SP2 ratio, the better the mechanical wear resistance and the adhesion to the substrate. However, if it is a low concentration of 10 or less, the SP3 / SP2 ratio may be gradually decreased with respect to the base material without affecting the wear resistance and the adhesion to the base material.

  In addition, by controlling the SP3 / SP2 ratio within a depth of 0.1 micron from the DLC coating surface of the guide wire to 0.01 or more and 10 or less, it goes without saying for human tissues such as blood, muscles and blood vessels. This is preferable because the mechanical properties can be suppressed while maintaining the welding resistance to the pharmaceutical used. When the SP3 / SP2 ratio is 10 or more, the compressive residual stress in the coating increases, so that it is difficult to peel off and the welding resistance can be easily maintained. Characteristics are degraded. Therefore, an SP3 / SP2 ratio in the range of 0.01 to 10 within a depth of 0.1 microns from the coating surface is appropriate.

  The adhesion between the carbon film and the base material in the medical guide wire with the DLC coating as described above is such that the SP3 / SP2 ratio is lower than the coating surface within 0.1 micron from the interface between the membrane and the core material. It became clear that it improves by having. Although there are various crystal structures that the carbon film can take, the present invention includes SP3 bonds (diamond bonds) and SP2 bonds (graphite bonds), and by increasing the proportion of SP2 bonds near the interface with the substrate, It improves the adhesion of the coating. Since SP3 bond (diamond bond) is the strongest bond, mechanical properties are excellent. However, when SP2 bond is more than SP3 bond, wear resistance is lowered, but in graphite bond, a hexagonal ring is formed. Since the carbon atoms that are formed take a layered structure and have a structure in which a weak van der Waals force acts between the layers of atoms, the effect of dispersing stress is exhibited, Interphase adhesion is improved.

In particular, the tip portion x of the guide wire has high lubricity, and SP3 / SP2 is made low in order to smoothly advance in the tubular tissue such as a catheter and a blood vessel, and is set to 0.01 or more and 0.2 or less. In the middle wire portion y where a more firm core wire is required, the rigidity of the core wire is increased by a large DLC film having a SP3 / SP2 ratio of 0.2 or more.
However, when the diamond-like carbon film becomes thick and the destruction of the layered structure, that is, the cohesive failure becomes remarkable, the peeling of the coating proceeds even if the interface failure does not occur. For this reason, it is preferable to control the SP3 / SP2 ratio to 10 or less and to make the DLC film thickness 0.02 microns or more and 2 microns or less, since the desired performance is exhibited more.

Coating of these medical members with a diamond-like carbon film can be realized by physical vapor deposition or chemical vapor deposition, but it can be uniformly coated in a complex shape and it is easy to adjust the SP3 / SP2 ratio in the film thickness direction. From the viewpoint, a parallel plate type high frequency plasma chemical vapor deposition (CVD) method is preferable.
Generally, a diamond-like carbon film is inserted into a vacuum apparatus together with a member to be coated, and a carrier gas such as hydrogen and a paraffin such as methane, ethane, propane, and butane as a carbon source, as well as ethylene, acetylene, and benzene are introduced. The formed gas is ionized to form on the member surface.

  In the present invention, the CVD method is used as a method for forming the DLC film on the guide wire. The apparatus is a parallel plate type high-frequency plasma CVD apparatus in which plasma is generated by high-frequency discharge that is installed in parallel in a chamber in a disk shape on an electrode. In addition, since the efficiency with which high-frequency power is consumed varies greatly depending on the impedance inside the chamber, a matching box (impedance matching unit) is installed outside the apparatus, and the efficiency is improved by adjusting it. The flow rate of acetylene gas, which is a raw material gas, can be controlled by a float type flow meter. The exhaust system was composed of a rotary pump and a mechanical booster pump, and the inside of the chamber was evacuated to 1.7 × 10 −3 Torr using the rotary pump and the mechanical booster pump. In forming the DLC film, acetylene was flowed into the chamber as a source gas, and the pressure was adjusted to 0.1 Torr. Plasma was generated by high frequency discharge, and a DLC film was deposited on a guide wire placed on the electrode for 10 seconds.

  Embodiments of the present invention will be described below based on examples, but the present invention is not limited thereto.

<Guide wire sliding characteristics evaluation test method>
In order to evaluate the sliding characteristics of the guide wire, a sliding experimental machine was manufactured, and FIG. 2 shows the shape of the artificial blood vessel of the guide wire sliding characteristics evaluation test machine.

  This testing machine was made for this research, and consists of the main body of the testing machine and an acrylic environment tank as the main parts. An electric motor is attached to the main body of the testing machine, and the arm portion can move up and down at a constant speed through the shaft. A load cell is attached to the arm portion as a load measurement detector, which is a portion for fixing the guide wire. Next, an artificial blood vessel can be fixed to the acrylic environmental tank in any shape, and a load measurement detector can be inserted into and inserted into the fixed artificial blood vessel. It is a mechanism to detect the resistance load of the guide wire against the wall.

<Evaluation test procedure>
(1) Three guide wires were prepared, a DLC film was coated on the first, an F-DLC film was coated on the second, and no treatment was applied on the third.
(2) Two types of artificial blood vessels to be fixed to the acrylic environment tank were set as shown in FIG.
(3) In each case, the point when the guide wire was completely inserted was set as the initial value point, and the zero point adjustment and the range were adjusted.
(4) The arm raising / lowering speed was set to 10 mm / second, and the guide wire was pulled out. (The arm was raised).
(5) The peak value of the load value read by the load detector when the guide wire was pulled out was used as monastic characteristic data.
(6) The above operation was repeated 30 times in consideration of data variation.
The above operation was performed for each of the three types of guide wires. The guide wire sliding characteristic evaluation experiment conducted with the shape of the artificial blood vessel fixed to the acrylic environmental tank having the type shown on the left in FIG. 2 was set to the experiment A, and the type shown on the right of FIG. The experiment conducted will be referred to as the B experiment.

  FIG. 3 shows a data comparison of the guide wire sliding characteristics in the A experiment. In the graph, the horizontal axis represents the type of guide wire, and the vertical axis represents the ratio. In the experiment A, the load value of the untreated guide wire is set as the reference value 1, and the load value of the guide wire coated with the DLC film and the guide wire coated with fluorine (F-DLC film) is set as a ratio. It is a summary of 30 measured values in terms of conversion. From this result, the plot of each data almost overlaps with the reference value, and no difference in sliding characteristics is recognized.

FIG. 4 shows the DLC-coated guidewire sliding characteristics comparison data of the present invention. The graph shows the number of tests on the horizontal axis and the guide wire coated with the DLC film and the guide wire coated with the F-DLC film when the load value of the untreated guide wire is set to the reference value 1 in the B experiment on the vertical axis. The ratio obtained by converting the load value as a ratio is taken. From this result, the plot group of the guide wire coated with the DLC film and the guide wire coated with the F-DLC film is in a state in which there is almost no variation in the line where the value is reduced by about 30% from the reference value. Can be judged. Moreover, when comparing the plot group of the guide wire coated with the DLC film and the plot group of the guide wire coated with the F-DLC film, the plot group of the guide wire coated with the DLC film is slightly more vertical. It can be determined that the line is reduced in proportion. When compared in the form expressed by mean value ± standard deviation (SD), the plot group of the guide wire coated with the DLC film is 0.60 ± 0.02, whereas the guide wire coated with the F-DLC film is This plot group is 0.71 ± 0.01, and both are antagonistic, but it is considered that the DLC film is slightly improved in sliding characteristics of the guide wire than the F-DLC film. That is, by coating the DLC film and the F-DLC film, the sliding characteristics of the guide wire are improved by about 30%, and it can be assumed that the improvement rate of the guide wire coated with the DLC film is slightly higher.

  Therefore, FIG. 5 shows the result of verifying whether or not this hypothesis is valid by performing a statistical analysis called a significant difference test.

<Examples 2 to 4 and Comparative Examples 1 to 4>
Table 1 shows the sample preparation conditions of Examples 2 to 4 and Comparative Examples 1 to 4 according to the present invention.

The obtained sample was evaluated by three types of tests.
Test 1: After 3 ml of blood was dropped and fixed, the test was peeled off with an adhesive tape. The amount of adhered cured blood remaining in the sample was compared.
○ Test 2: The critical load was compared until the coating peeled when scratched from the coating while increasing the load continuously from 0 to 10 N with a diamond indenter.
Stripping below 5N: ▲,
Peel at 6-10N: ○,
No peeling (minor defect): ◎
○ Test 3: While rotating a ring-shaped (30φ) carbon steel (S20C) at 0.2 m / s, the sample coating surface was slid in the blood with a load of 100 g, and the friction amount after 10 minutes was determined as the wear width. Compared.
5 mm or more: X,
3 to 5 mm: Δ,
1-3 mm: ○,
1mm or less: ◎ or less

  The results of Test 1, Test 2 and Test 3 for each sample shown in Table 1 are summarized in Table 2.

Conventionally, applying a DLC coating containing fluorine to a medical guide wire improves the antithrombogenic properties of the medical member, but the coating tends to peel off due to deformation during use of the member, However, in the present invention, the treatment of the diamond-like carbon coating is performed 5 to 30 mm from the distal end of the medical guide wire . The SP3 / SP2 ratio of the coating is 0.01 or more and 0.2 or less at the wire tip that is in the range, and the SP3 / SP2 of the coating is at the wire intermediate portion that is in the range of 100 to 3000 mm from the tip. ratio, has an area of 0.2 or more, lubricity is high by the sliding characteristics improved by about 30%, smooth catheters and vascular and digestive tract and the like in the tubular tissue of And rows, with the strength of moderate waist has enabled easy medical guide wire operation. As a result, it is possible to obtain a thin-film medical covering member that has resistance to adhesion to pharmaceuticals used in addition to human tissues such as blood, muscle, and blood vessels, and also has strong adhesion to the member and high wear resistance. .

Claims (2)

A medical guide wire coated with a diamond-like carbon film,
In the wire tip where the coating of the diamond-like carbon film is in the range of 5 to 30 mm from the tip of the medical guide wire, the SP3 / SP2 ratio of the coating is 0.01 or more and 0.2 or less, A medical guide wire coated with a diamond-like carbon film, wherein an SP3 / SP2 ratio of the coating is 0.2 or more at a wire intermediate portion in a range of 100 to 3000 mm from the tip . The medical guide wire according to claim 1, wherein the diamond-like carbon film has a thickness of 0.02 to 2 microns.

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