JP2006122435A - Ceramic coated medical instrument and medical apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To exclude harmful effects on living tissue by the use of medical instruments such as a pace maker, a stent, a catheter, an artificial bone, an artificial joint or an artificial tooth. <P>SOLUTION: The metallic medical instrument at least partially embedded or inserted in the living body is surface coated with an insulating ceramic film with resistivity, ρ≥10<SP>5</SP>Ω×m, at least for the portion in direct contact with the living body. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a medical instrument that is at least partially embedded or inserted into a living body and a medical device that controls the supply or circulation of blood or treatment liquid into the living body.
In the present invention, examples of medical instruments include living body pacemakers, stents, catheters, artificial bones, artificial joints, artificial teeth, and the like, and examples of medical apparatuses include a blood cleaning apparatus or a treatment liquid cleaning apparatus. This is a representative example.

  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.

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.
In addition, since blood and treatment liquid used for medical use require clean blood and treatment liquid that does not coagulate during use, development of an excellent medical device with such a function is required.

However, for example, when the current puncture needle is used as the puncture needle described above, since the base material of the needle is a conductive metal having a high conductivity (resistivity ρ: 10 ⁻⁶ to 10 ⁻⁸ Ω · m), It has been pointed out that it adversely affects cells around tissue pieces collected from lesions and puncture needles pierced in lesions. It has also been pointed out that when a metal member is brought into contact with or inserted into a living body for a long time, metal ions dissolve and adversely affect the living body.

Therefore, Ti or Ti alloy, which is considered to be a metal that has a relatively small adverse effect on the living body, is used as a medical device, for example, some pacemakers, stents, catheters, artificial bones, artificial joints, and artificial teeth. (For example, Non-Patent Document 1).
SGSteinemann, Titanium-The material of choice ?, Periodon-tology: 2000, 17 (1998), P.7-21

However, since metal Ti or Ti alloy is not only expensive, but also difficult to precisely process due to the material, it is difficult to downsize the above-mentioned medical devices or to manufacture very fine ones such as stents. there were.
Therefore, development of a material that eliminates these drawbacks is eagerly desired.

  In this respect, if a ceramic coating material can be used, there is little adverse effect on the human body, and if a steel material (for example, austenitic non-magnetic stainless steel) can be used as a material, it is considered that it can sufficiently withstand precision machining.

As a medical instrument coated with ceramic, a medical incision / press-in instrument having a reduced frictional resistance during incision by coating a surface of a medical knife with a diamond film has been proposed (for example, Patent Document 1).
However, the above diamond film is formed by coating the substrate using plasma CVD (Chemical Vapor Deposition) heated to 500 to 1300 ° C., and the diamond film has a large thermal expansion difference. There was a problem that it was easy to peel.
Japanese Examined Patent Publication No. 6-20464

  Therefore, for example, when considering the case where the above technique is applied to a puncture needle, an injection needle, etc., these needles are inevitably bent to some extent during their use, so the danger of the diamond film peeling off is extremely high, Therefore, this technique cannot be applied to medical instruments.

By the way, recently, the inventors have plasma-coated a thin TiN ceramic film on a ferritic stainless steel plate, and then added plastic working by 180 ° bending deformation, the TiN ceramic film appears to be a metal at the crack occurrence position. A new fact has been elucidated that has a unique concave shape and shows local elongation.
This phenomenon suggests that the ceramic film, which is considered to be very brittle, is elongated in the plastic working like the metal and can be processed.
Yukio Iguchi: 2001 International Photo Exhibition Winning Works Reference (Indianapolis, USA, 5-11-2001. Jointly IMS (International Metallographic Society) and AMS (American Society of Metals)

Therefore, the inventors immediately tried to form a TiN ceramic film on the surface of the puncture needle made of stainless steel by 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 film had extremely good adhesion to the puncture needle, and peeling did not occur with some bending.

  However, when a puncture needle coated with this TiN ceramic film is used, the adverse effects on the cells around the puncture needle that punctures the collected tissue piece or lesion are completely eliminated, even if not as much as conventional metal puncture needles. I couldn't wipe it out.

  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.

For example, when using a puncture needle in which ceramic films with various resistivity ρ are formed on the surface of a stainless steel substrate, the results of examining the influence on living tissue are shown as follows: resistivity ρ and tissue damage (TDD: In relation to Texture Damage Degree (pathological examination by microscopic observation), if the TDD is 0.40 or less, more preferably 0.35 or less, it is considered that there is no adverse effect on the living tissue. That is, 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.

Based on the above findings, the inventors have described that a medical ceramic-coated needle characterized by having an insulating ceramic coating having a resistivity of 10 ⁵ Ω · m or more on part or all of the surface of a metal needle. (Patent Document 2).
JP 2003-210579 A

  The present invention is an application of the above technique to a medical instrument in which at least a part is embedded or inserted into a living body, such as a living body pacemaker, a stent, a catheter, an artificial bone, an artificial joint, and an artificial tooth. It is an object of the present invention to propose a ceramic-coated medical instrument that does not have any adverse effect on living tissue when using such a medical instrument.

  Further, the present invention is an application of the above-described technique to a medical device for biological treatment, such as a blood cleaning device or a treatment liquid cleaning device. An object of the present invention is to propose a ceramic-coated medical device capable of purifying such blood or treatment liquid when supplying or circulating the treatment liquid.

That is, the gist configuration of the present invention is as follows.
(1) A metal medical instrument that is at least partially embedded or inserted into a living body, and at least a part that is in direct contact with the living body has a resistivity ρ of 10 ⁵ Ω · m or more. A ceramic-coated medical device characterized by being coated with an insulating ceramic film.

(2) A medical device that controls the supply or circulation of blood or treatment liquid into the living body, and resists at least the inner surface of the metal capillary tube nozzle that supplies or circulates the blood or treatment liquid into the living body. A ceramic-coated medical device characterized by being coated with an insulating ceramic film having a rate ρ of 10 ⁵ Ω · m or more.

(3) The ceramic-coated medical device according to (1), wherein the ceramic film has a thickness of 0.05 to 5.0 μm.

(4) The ceramic-coated medical device according to (2), wherein the thickness of the ceramic film is 0.05 to 5.0 μm.

(5) The ceramic-coated medical device according to (1), wherein the medical device is any one of a living body pacemaker, a stent, a catheter, an artificial bone, an artificial joint, or an artificial tooth.

(6) The ceramic-coated medical device according to (2), wherein the medical device is either a blood cleaning device or a treatment liquid cleaning device.

ADVANTAGE OF THE INVENTION According to this invention, the ceramic coating | coated excellent in insulation and adhesiveness can be stably coat | covered to the predetermined site | part of a medical instrument or a medical device.
As a result, according to the present invention, it is possible to provide a ceramic-coated medical instrument that does not adversely affect a living tissue.
In addition, according to the present invention, it is possible to provide a ceramic-coated medical device in which blood or therapeutic liquid can be purified when blood or therapeutic liquid is supplied or circulated in a living body.

The present invention will be specifically described below.
In the medical instrument of the present invention, a ceramic coating having excellent insulating properties and excellent adhesion and wear resistance is formed on a portion that is in direct contact with a living body. As a base material for these medical instruments, any metal material can be used, but austenitic stainless steel is particularly preferable. This is because austenitic stainless steel is non-magnetic, does not rust on the surface, and is easy to process precisely.
As for the metal thin tube nozzle of the medical device, any base material can be used as long as it is a metal material, but austenitic stainless steel is particularly preferable.
In addition, when manufacturing metallic thin tube nozzles for these medical instruments and medical devices using stainless steel as a base material, the stainless steel material is continuously cast and subjected to hot rolling, cold rolling, bright annealing. After being performed, it may be processed into various desired shapes by precision processing.

Next, the surface of the metal capillary nozzle of the obtained medical instrument or medical device is cleaned by ultrasonic cleaning or electrolytic polishing, and then a ceramic film is formed. It is important to use an insulating ceramic having a resistivity ρ of 10 ⁵ Ω · m or more. This is because ceramics having a resistivity ρ of less than 10 ⁵ Ω · m cannot completely eliminate the adverse effects on living tissue, and it is difficult to sufficiently clean blood and treatment liquid.

In the present invention, the reason (mechanism) for cleaning the blood and the treatment liquid by coating the inner surface of the metal capillary nozzle with an insulating ceramic coating is as follows.
The ceramic coating obtained by plasma coating has a typical amorphous structure with phase contrast and is different in properties from ordinary crystallized thin films, so it is cleaned when passed through a nozzle coated with such a ceramic coating. Is thought to be possible.
Further, in the present invention, the therapeutic liquid includes a contrast agent, a penetrant, and the like in addition to various chemical solutions.

Here, as the ceramic having a resistivity ρ of 10 ⁵ Ω · m or more, at least one selected from nitrides, carbides or oxides of Al, B and Si is advantageously suitable.
The coating thickness of the ceramic film is preferably 0.05 to 5.0 μm. This is because it is difficult to ensure sufficient insulation if the ceramic film thickness is less than 0.05 μm, while it is difficult to ensure adhesion between the ceramic film and the substrate if the ceramic film thickness exceeds 5.0 μm. This is because the coating increases the cost.

  Furthermore, the method for coating the ceramic film as described above is not particularly limited, but it is advantageous to coat by a dry plating method. As such a dry plating method, the magnetron sputtering method capable of high ionization and high-speed film formation is optimal, but other known methods such as RF (Radio Frequency), hollow cathode discharge method, arc discharge method, etc. A PVD coating method, a CVD coating method capable of coating at a relatively low temperature, and a high plasma CVD coating method can also be used.

Here, the preferable coating conditions of the ceramic film by the magnetron sputtering method are as follows.
For example, when a ferrosilicon target is used to perform SiN _X coating, input power: 5 to 30 kW, vacuum degree: 0.1 to 0.4 Pa (0.8 to ³ × 10 ⁻³ Torr), Ar gas: 50 to 1000 sccm, N ₂ gas: 50 to 1000 sccm are the optimum conditions.

In addition, the medical instrument of this invention should just provide the ceramic coating | cover with respect to the site | part which contacts a biological tissue directly. At this time, in order to coat uniformly, it is preferable to coat while rotating the coating tool with respect to the target in the X-axis direction and the Y-axis direction.
In addition, the fine tube nozzle that has been drawn with high accuracy does not come into direct contact with the living tissue, but it is necessary to coat at least about 10 mm from the tip of the thin tube nozzle not only on the outer surface but also on the inner surface. In this case, as previously disclosed in Japanese Patent Application Laid-Open No. 2003-310759, the present inventors advance the capillary nozzle in parallel with the traveling direction of the vapor deposition particles and advance the tip of the capillary nozzle. It is advantageous to perform the coating by placing it facing the vapor deposition particles. According to this method, the ceramic film can be effectively coated not only on the outer surface of the capillary tube nozzle but also on the inner surface.

C: 0.031 mass%, Si: 0.22 mass%, Mn: 0.11 mass%, P: 0.009 mass%, S: 0.015 mass%, Cr: 17.7 mass% and Ni: 9.4 mass%, the balance being Fe and inevitable Austenitic stainless steel material with a composition of mechanical impurities is continuously cast, hot-rolled-cold-rolled-bright-annealed, and then precision-processed to produce the outer frame, stent, catheter, and artificial A joint was created. Further, a thin tube nozzle having an outer diameter: 0.5 mmφ, an inner diameter: 0.3 mmφ, and a length: 40 mm was prepared.
Subsequently, these medical devices and capillary nozzles were ultrasonically cleaned in an alcohol solution, and then various ceramic films were coated using a magnetron sputtering method. That is, an SiNx film is used for the outer frame and stent of a living body pacemaker, an SiO ₂ film is used for the catheter, an Al ₂ O ₃ film is used for the artificial joint, and a BN film is used for the capillary tube nozzle. Coated to thickness.

Table 1 shows the results of investigations on the workability and tissue damage (TDD) of the ceramic coated biological pacemaker outer frame, stents, catheters and artificial joints thus obtained, and the workability and cleanability of the ceramic coated capillary nozzle. Show.
The cleaning ability of the ceramic-coated capillary tube nozzle was evaluated as follows.
The degree of adhesion in the tube when passing through a normal glass tube was taken as 1, and the adhesion amount when passing through a ceramic-coated capillary tube nozzle was evaluated as good if it was 0.5 or less, which is half or less.

As shown in the table, the ceramic coated pacemaker outer frame, stent, catheter and artificial joint obtained according to the present invention are not only good in workability but also have a tissue damage degree (TDD) of 0.35 or less. There was no adverse effect on living tissue. It can also be seen that the ceramic-coated capillary tube nozzle is also rich in workability and excellent in cleaning ability.
In particular, for the outer frame of the SiNx coated pacemaker, the insulation and film adhesion were investigated, and the electrical resistance was infinite, and the adhesion was excellent even with 20 mmφ 180 ° bending and good insulation and film It was confirmed to have adhesion.

Claims (6)

At least a part of a medical device made of metal that is embedded or inserted into a living body, and at least a part that is in direct contact with the living body has an insulating surface with a resistivity ρ of 10 ⁵ Ω · m or more. A ceramic-coated medical device characterized by being coated with a ceramic film. A medical device that controls supply or circulation supply of blood or treatment liquid into a living body, and has a resistivity ρ on at least an inner surface of a metal capillary nozzle that supplies or circulates the blood or treatment liquid into the living body. A ceramic-coated medical device characterized by being coated with an insulating ceramic film of 10 ⁵ Ω · m or more.   2. The ceramic-coated medical device according to claim 1, wherein the thickness of the ceramic film is 0.05 to 5.0 [mu] m.   The ceramic-coated medical device according to claim 2, wherein the thickness of the ceramic film is 0.05 to 5.0 µm.   2. The ceramic-coated medical device according to claim 1, wherein the medical device is any one of a biological pacemaker, a stent, a catheter, an artificial bone, an artificial joint, or an artificial tooth.   2. The ceramic-coated medical device according to claim 2, wherein the medical device is either a blood cleaning device or a treatment liquid cleaning device.