JP4193597B2 - Method for manufacturing a ceramic-coated medical device - Google Patents

Description

【００４１】
同表に示したとおり、本発明に従い得られた医療用器具はいずれも、絶縁性に極めて優れ、また被膜剥離が生じなかった最小径も全て25mm以下と被膜密着性も良好であり、さらに抗菌性にも優れていた。
【００４２】
【発明の効果】
かくして、本発明によれば、絶縁性および密着性に優れ、さらには抗菌性にも優れたセラミック被覆医療用器具を安定して得ることができる。
従って、本発明に従うセラミック被覆医療用器具を用いれば、生体組織や細胞に対して何らの悪影響を及ぼすことがない。
【図面の簡単な説明】
【図１】 被覆セラミックの抵抗率ρと組織損傷度（ＴＤＤ）との関係を示した図である。
【図２】 抵抗率ρと酸素ガスの導入量との関係を示した図である。
【図３】 ＧＤＳによる表面から膜厚方向の元素分析結果を示した図である。[0001]
BACKGROUND OF THE INVENTION
The present invention primarily puncture needle, suture needle, biological tweezers, forceps, etc. surgical scissors and scalpel, a method of manufacturing a medical instrument instrument has a portion in direct contact with the living body.
The present invention has been concerned in the past by using a ceramic coating excellent in insulation, adhesion, and antibacterial properties on the surface of at least a part of such a medical device that is in direct contact with a living body. It completely eliminates adverse effects on living tissues and cells.
[0002]
[Prior art]
Recent advances in medical technology are remarkable. For example, in the examination of the liver, pancreas, etc., to obtain data that cannot be obtained by blood tests of patients, ultrasound and CT (computed tomography) examinations using echoes are used. , MRI (magnetic resonance imaging) examination that shows cross-sectional images of various organs using strong magnetism and radio waves, angiography examination that injects a contrast medium through a thin tube (catheter), and visualizes the state of the blood vessel Widely used.
[0003]
According to these blood tests and various image diagnoses, the presence of a lesion such as cancer can be diagnosed. However, for a definitive diagnosis, a histopathological examination of the lesion by a liver biopsy or the like is required.
Usually, in such an inspection, a method of collecting a tissue piece by directly inserting a special puncture needle into a lesioned part is employed.
[0004]
However, when the current metal puncture needle is used, the base material of the needle is a conductor metal (resistivity ρ: 10 ⁻⁶ to 10 ⁻⁸ Ω · m) with excellent electrical characteristics. It has been pointed out that it has an adverse effect on the cells around the tissue pieces collected from the above and the puncture needles pierced by the lesion.
[0005]
In this regard, if a ceramic puncture needle (hereinafter simply referred to as a ceramic puncture needle or a ceramic needle) is used, it is considered that the cells around the puncture needle that has been punctured into the collected tissue piece or lesion are not adversely affected. .
However, ceramic puncture needles and ceramic needles are very fragile and easy to break, so they are not used at all.
[0006]
In order to solve the above problem, the inventors previously stated that “a part or all of the surface of a metal needle has an insulating ceramic coating having a resistivity ρ of 10 ⁵ Ω · m or more. A characteristic “ceramic coated needle for medical use” was developed (see, for example, Patent Document 1).
With the development of the above technology, tissue fragments can be collected without causing breakage during use, and without adversely affecting the cells around the puncture needle that pierces the lesion. .
[0007]
In the development of the above invention, the inventors firstly used the surface of a normal metal puncture needle as a puncture needle that does not adversely affect cells around the collected tissue piece or puncture needle pierced with a lesion. It was considered to deposit a ceramic coating on the surface.
However, even if a ceramic coating is formed on the surface of an extremely thin cylindrical body such as a puncture needle, if the adhesion is poor, the ceramic coating is peeled off during use, and the intended purpose cannot be achieved. In particular, puncture needles, injection needles, and the like are inevitably bent to some extent during their use, so the danger of peeling off is extremely high.
[0008]
With regard to the formation of such a ceramic coating, a medical incision / press-in instrument having a reduced frictional resistance during incision by coating the surface of a medical knife with a diamond film has been proposed (see, for example, Patent Document 2). .
However, the above diamond film is formed by heating the substrate to 500 to 1300 ° C., and there is a problem that the diamond film is easy to peel off because of the large thermal expansion difference between the substrate and the diamond film. It cannot be applied to a puncture needle or the like targeted by the present invention.
[0009]
By the way, recently, the inventors have plasma-coated a thin TiN ceramic film on a ferritic stainless steel plate and then applied plastic working by 180 ° bending deformation. The new fact which shows a local elongation with a unique concave shape was clarified (for example, Non-Patent Document 1).
This phenomenon suggests that the ceramic coating, which is considered to be very brittle, is elongated in the plastic working like the metal and can be processed.
[0010]
Therefore, the inventors immediately tried to form a TiN ceramic coating on the surface of the puncture needle made of stainless steel using the ceramic coating method in a high vacuum / high plasma atmosphere described above.
As a result, it was confirmed that the obtained TiN ceramic coating had extremely good adhesion to the puncture needle, and peeling did not occur with some bending.
[0011]
However, when a puncture needle coated with this TiN ceramic coating is used, even if it is not as much as a conventional metal puncture needle, the adverse effect on the cells around the puncture needle that has punctured the collected tissue piece or lesion is completely eliminated. I couldn't wipe it out.
[0012]
Therefore, as a result of intensive investigations to solve this point, it was found that the ceramic for coating is not limited to ceramic, and it needs to be an insulator material having a high resistivity ρ. It was.
[0013]
FIG. 1 shows the results of investigating the influence on the living tissue when using a puncture needle with ceramic coatings with various resistivity ρ on the surface of a stainless steel substrate. TDD: Texture Damage Degree; pathological examination by microscopic observation) In addition, this tissue damage degree (TDD) is obtained by processing the cut tissue surface from a cell tissue photograph to obtain uneven lines, and the arithmetic average roughness (Ra) conforms to JIS B 0633 (ISO 4288). And obtained from the conversion formula TDD = 0.0563Ra−0.0911. This conversion formula is a ceramic coated needle in which the average value of the surface roughness Ra of the cut surface of the tissue cut by a conventional stainless steel puncture needle is 10.5 μm, the TDD at this time is 0.5, and the resistivity ρ is ∞. It was defined that the smallest value of the surface roughness Ra of the cut surface of the cut tissue was 3.4 μm, and the TDD at this time was 0.1.
And if said TDD is 0.40 or less, Preferably it is 0.35 or less, it can be said that there is no bad influence by damage, such as destruction and tearing, to a biological tissue.
[0014]
As shown in the figure, by using a ceramic for coating having a resistivity ρ of 10 ⁵ Ω · m or more, a good result with a TDD of 0.40 or less could be obtained. In the figure, a puncture needle made of stainless steel without a ceramic coating has a resistivity ρ of 7 × 10 ⁻⁶ , and a puncture needle coated with TiN as a ceramic has a resistivity ρ of 3 × 10 ^4. . Here, the resistivity is a volume resistivity determined by a four-terminal method in accordance with ASTM D-991.
[0015]
Thus, the inventors disclosed in the above-mentioned patent document 1 “characteristically having an insulating ceramic film having a resistivity ρ of 10 ⁵ Ω · m or more on a part or the whole surface of a metal needle. Developed a ceramic coated needle for medical use.
[0016]
The inventors have also found that the above technique has the same effect on medical instruments other than medical needles such as puncture needles, for example, biotweezers and insulators, surgical scissors, surgical scalpels, and the like. A patent application was filed separately for the headline (see, for example, Patent Document 3).
[0017]
All of the above-mentioned inventions ensure the adhesion between finely processed metal needles and medical devices and insulating ceramic thin films by adopting a ceramic coating method in a high vacuum and high plasma atmosphere. It is something to try.
[0018]
[Patent Document 1]
Japanese Patent Application No. 2002-12863 Specification (Claims)
[Patent Document 2]
Japanese Patent Publication No. 6-20464 (Claims)
[Non-Patent Document 1]
“Ikuo Iguchi: 2001 International Photo Exhibition Winning Works Reference (Indianapolis, Nov. 5-8, 2001. jointly IMS (International Metallographic Society) and ASM (American Society of Metals))”
[Patent Document 3]
Japanese Patent Application No. 2002-111899 (Claims)
[0019]
[Problems to be solved by the invention]
The present invention relates to the improvement of the above-described technology. In forming the ceramic coating, the interface between the iron matrix and the ceramic coating (initial coating layer) improves the adhesion as a mixed layer of both, while at least the most of the ceramic coating. further improve the more elevated insulative resistivity ρ for the surface layer, and further aims to propose an advantageous method for producing an antimicrobial be remarkably improved thereby ceramic coated medical fixtures.
[0022]
[Means for Solving the Problems]
That is, the gist configuration of the present invention is as follows.
1 . When the surface of at least a part of a metallic medical device that is in direct contact with a living body is coated with a ceramic coating by plasma coating,
A method for producing a ceramic-coated medical device, wherein 5 to 500 sccm of O ₂ is introduced into the plasma coating atmosphere in the latter half of the plasma coating.
[0023]
2 . 2. The method for producing a ceramic-coated medical device according to 1 above, wherein the ceramic coating is at least one selected from nitrides, oxides or carbides of Al, B, Si, Cr and Ti.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be specifically described below.
In the present invention, the part that comes into direct contact with the living body of a medical instrument such as a puncture needle, suture needle, tweezers for living body, forceps, scissors for operation, and scalpel for operation has excellent insulation, adhesion, and antibacterial properties. Any ceramic material can be used as the base material for these medical devices since a ceramic coating is formed, but stainless steel is particularly preferred.
This is because the surface of stainless steel does not rust and precision processing is easy, and ferritic stainless steel is particularly suitable.
[0025]
For example, when these medical instruments are manufactured using stainless steel as a base material, a stainless steel material is continuously cast, subjected to hot rolling-cold rolling-bright annealing, and then subjected to various kinds of precision processing. Process into shape. In addition, what is necessary is just to perform this process process according to a prior art.
[0026]
Next, the surface of the obtained medical instrument such as a puncture needle, suture needle, living body tweezers, forceps, surgical scissors and scalpel is cleaned by ultrasonic cleaning, electrolytic polishing, etc., and then a ceramic coating is applied. However, it is important to use an insulating ceramic having a resistivity ρ of 10 ⁵ Ω · m or more as such a ceramic. This is because ceramics having a resistivity ρ of less than 10 ⁵ Ω · m cannot completely eliminate the adverse effects on the cells around the contacted tissue piece or lesion.
[0027]
When coating the ceramic coating as described above, a plasma coating method is used. Here, the plasma coating method is a method in which plasma (a gas containing ionized particles) is generated in a vacuum, and the surface of the material to be coated is coated with the generated plasma.
The plasma coating method is not particularly limited, but it is optimal to apply a magnetron sputtering method capable of high ionization and high-speed film formation. In addition, known PVD coating methods such as RF (Radio Frequency), a hollow cathode discharge method, and an arc discharge method can also be used.
[0028]
Here, the preferred coating conditions for the ceramic coating by magnetron sputtering are as follows.
For example, when a ferrosilicon target is used to perform SiN _X coating, input power: 5 to 30 kW, vacuum degree: 0.8 to 3 × 10 ⁻³ Torr, Ar gas: 50 to 1000 sccm, N ₂ gas: 50 to 1000 sccm is the optimum condition.
[0029]
In the plasma coating as described above, it is possible to coat a ceramic coating with excellent insulation having a resistivity ρ of 10 ⁵ Ω · m or more.
By the way, among the naturally occurring ceramic materials, there are some excellent in insulation characteristics with a resistivity ρ of 10 ¹⁶ Ω · m or more. In that case, it is shown that the insulating property is good to the extent that the resistivity ρ cannot be measured by the four-terminal method using a normal metal or the like.
However, the above manufacturing method cannot provide a ceramic coating with such an excellent insulating property.
[0030]
Therefore, the inventors have conducted extensive research to improve this point, and as a result, it has been found that it is effective to increase the O ₂ concentration in the coating atmosphere during plasma coating in order to increase the insulation of the ceramic coating. Got.
That is, when the O ₂ concentration in the coating atmosphere was increased, a very excellent insulating property of resistivity ρ ≧ 10 ⁹ Ω · m could be obtained when the ceramic coating was Al, B, or Si. In addition, antibacterial properties are also greatly improved.
In addition, even in the case of Cr, Ti, which has conventionally been difficult to obtain a resistivity ρ of 10 ⁵ Ω · m or more, by increasing the O ₂ concentration in the coating atmosphere, the resistivity ρ ≧ 10 ⁵ Ω · m Therefore, the excellent insulation properties can be obtained.
[0031]
However, it was also found that if the O ₂ concentration in the atmosphere is increased from the initial stage of plasma coating, the adhesion is inhibited.
Therefore, in the present invention, the O ₂ concentration in the coating atmosphere is increased only in the latter half of the plasma coating.
The latter half of the coating in which oxygen gas is to be introduced into the coating atmosphere is a stage where the ratio of iron in the mixed layer of the iron matrix and the ceramic is 20% or less (preferably 10% or less). When this stage is converted into the film thickness of the ceramic coating, it corresponds to the surface layer portion in the total film thickness: about 10 to 50%.
[0032]
2, in the case of 1.0μm thick coating of SiN _X on the surface of the puncture needle with a magnetron sputtering method, the results of examining the relationship between the resistivity ρ and the oxygen gas introduction rate of SiN _X ceramic coated needle Show. Oxygen gas was introduced only in the latter half of magnetron sputtering (coating surface layer: equivalent to 0.5 μm thickness).
[0033]
As is apparent from the figure, the resistivity ρ increases rapidly by introducing oxygen gas. In particular, when the amount of introduced oxygen gas is 5 sccm or more, the resistivity ρ is 10 ⁹ Ω · m or more, and when the amount of introduced oxygen gas is 50 sccm or more, the resistivity ρ exhibits an extremely high value of 10 ¹³ Ω · m or more. became.
However, when the oxygen gas introduction amount exceeded 500 sccm, the effect of improving the resistivity ρ reached saturation.
Therefore, in the present invention, in the latter half of the plasma coating, the amount of oxygen to be introduced into the coating atmosphere is limited to a range of 5 to 500 sccm. Preferably it is the range of 50-500 sccm.
[0034]
Next, FIG. 3 shows the analysis results of the Fe, N, O, and Si components in the film thickness direction by glow discharge emission surface analysis of the SiN _X ceramic coating.
As shown in the figure, each component changes in the film thickness direction. Among them, O is mostly in the range of 0.5 μm from the surface. This means that the ceramic coating has a tilting function over the film thickness direction, which makes it possible to form a ceramic coating that is excellent in adhesion and excellent in insulation and antibacterial properties.
[0035]
Here, as described above, at least one selected from the nitrides, oxides or carbides of Al, B, Si, Cr and Ti is advantageously suitable as the ceramic coating to be coated.
The coating thickness of the ceramic coating is preferably 0.05 to 5.0 μm. This is because it is difficult to ensure sufficient insulation unless the ceramic film thickness is less than 0.05 μm, while it is difficult to ensure adhesion between the ceramic coating and the substrate if the ceramic film thickness exceeds 5.0 μm. This is because the coating increases the cost.
The thickness was measured using a stylus-type film thickness meter Alpha-step 200 (manufactured by Tencor instrument Co., Ltd.) to measure the level difference between the coated area and the uncoated area on another glass slide.
[0036]
In the plasma coating according to the present invention, when the ceramic to be coated is a nitride or carbide, a simple material (metal body) can be used as a target. In some cases, it is preferable to use an oxide for the target itself.
In forming the ceramic coating, it is more advantageous to arrange a magnet around the target and use the RF mechanism to achieve a high plasma atmosphere and to obtain an excellent resistivity.
[0037]
Furthermore, the coating of the ceramic coating on the surface of a medical instrument such as the puncture needle, suture needle, tweezers for living body, forceps, scissors for operation and scalpel of the present invention does not need to be applied to the entire surface of these instruments, What is necessary is just to give with respect to the site | part which contacts a biological tissue at least in the case of the use.
[0038]
【Example】
Example 1
Ferrite system containing C: 0.033%, Si: 0.20%, Mn: 0.15%, P: 0.008%, S: 0.008%, Cr: 17.7%, with the balance being Fe and inevitable impurities. After continuous casting of stainless steel, hot rolling-cold rolling-bright annealing, precision processing, puncture needle (outer diameter: 2.0 mm, length: 170 mm), biotweezers, forceps, surgery Scissors and scalpels were made.
Next, these medical instruments were ultrasonically cleaned, and then various ceramic coatings shown in Table 1 were formed in a high plasma atmosphere by using a magnetron sputtering method (some RF was also used). At that time, the first half of the coating was performed in a normal coating atmosphere, and oxygen gas was introduced into the atmosphere at various ratios until the second half of the coating (coating surface layer portion: equivalent to 0.5 μm thickness). The film thickness was about 1.0 μm. The coating conditions at this time were input power: 6 kW, Ar gas: 100 sccm, N ₂ gas: 130 sccm (No. 1, 3, 5).
[0039]
Table 1 also shows the results of examining the insulating properties (resistivity ρ), adhesion and antibacterial properties of the ceramic coating in the medical device thus obtained.
In Table 1, resistivity ρ = ∞ means that resistivity ρ exceeds 10 ⁹ Ω · m.
In addition, the adhesion of the ceramic coating is the minimum diameter at which the coating of the ceramic coated steel plate coated with the ceramic coating on the surface of a separately prepared stainless steel plate is wound around a bar of various diameters, and the coating does not peel off. It was evaluated with.
Furthermore, the antibacterial evaluation was carried out by a method based on “Antimicrobial processed product-antibacterial test method / antibacterial effect JIS Z 2801 (2000)”. That is, SUS 304 steel was used as a comparative material, and the sterilization rate defined by the following formula was evaluated. If this sterilization rate is 99% or more, it can be said that the antibacterial effect is excellent.
Bacteria reduction rate = (number of viable bacteria in comparison material-number of viable bacteria in ceramic coating material) / (number of viable bacteria in comparison material) x 100 (%)
[0040]
[Table 1]

[0041]
As shown in the table, all of the medical devices obtained in accordance with the present invention are extremely excellent in insulation, and the minimum diameter at which no film peeling occurred is 25 mm or less, and the film adhesion is good. It was also excellent in performance.
[0042]
【The invention's effect】
Thus, according to the present invention, it is possible to stably obtain a ceramic-coated medical instrument that is excellent in insulation and adhesion, and also excellent in antibacterial properties.
Therefore, if the ceramic-coated medical device according to the present invention is used, it does not have any adverse effect on living tissue or cells.
[Brief description of the drawings]
FIG. 1 is a graph showing the relationship between the resistivity ρ of a coated ceramic and the degree of tissue damage (TDD).
FIG. 2 is a graph showing the relationship between resistivity ρ and the amount of oxygen gas introduced.
FIG. 3 is a diagram showing the results of elemental analysis in the film thickness direction from the surface by GDS.

Claims (2)

When the surface of at least a part of a metallic medical device that is in direct contact with a living body is coated with a ceramic coating by plasma coating,
A method for producing a ceramic-coated medical device, wherein 5 to 500 sccm of O ₂ is introduced into the plasma coating atmosphere in the latter half of the plasma coating. 2. The method of manufacturing a ceramic-coated medical device according to claim 1 , wherein the ceramic coating is at least one selected from nitrides, oxides or carbides of Al, B, Si, Cr and Ti.

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