JPH04220261A - Diamond-coated member for living body - Google Patents

Abstract

PURPOSE:To provide the diamond-coated member for the living body which has excellent biocompatibility, is free from wear and corrosion and can prevent the generation of a fault in a stationary section particularly by impact load. CONSTITUTION:This diamond-coated member for the living body has a base material which consists of a metal or ceramics and a high-polymer compd. of a high melting temp. joined to a part thereof or covering the entire part thereof and a coating layer of diamond or diamond-like carbon which is provided in the entire part or a part of the surface of this base material.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to biomaterials such as artificial joints that are well suited to living organisms, have excellent wear resistance, are free from damage due to applied loads, and can withstand long-term use.

0002

[Prior Art] Biological components such as artificial joints, artificial heart valves, artificial tooth roots, and artificial bones have corrosion resistance because they are used in living organisms, and do not cause rejection reactions from living organisms, and are the cause of tumors. It is necessary to satisfy conditions such as not being

Conventionally, metals such as stellite and titanium have been widely used as materials that meet these conditions, but these metals also have some drawbacks. For example, when Stellite is used as an artificial joint, the frictional parts wear out unexpectedly quickly, so not only does it cease to function as a joint in a relatively short period of time, but also wear debris accumulates in the frictional parts, causing inflammation. It has been reported that this can cause problems, so long-term use for several decades has been impossible. It is also known that corrosion progresses and blood coagulation occurs on the surface of some metal materials, albeit slightly.

[0004] Furthermore, biological parts using ceramics have already been put into practical use, but while ceramics have excellent wear resistance and corrosion resistance, they have drawbacks such as low strength and brittleness that makes it impossible to make thin parts. Therefore, its uses were limited to things like artificial tooth roots.

[0005] Therefore, in order to solve the problems of biological parts made of metal materials, for example,
As shown in Japanese Patent No. 66, a biomaterial member has been proposed in which the surface of a metal such as stellite or titanium is coated with diamond or diamond-like carbon. Diamond is resistant to corrosion by most gases and liquids, has high hardness, and is highly compatible with living organisms. Diamond-like carbon also has properties almost similar to diamond.

However, to form a coating layer made of diamond or diamond-like carbon, a gas phase synthesis method such as a normal CVD method that uses hydrogen and hydrocarbons such as methane as raw material gases is used. Generally, the temperature of the metal base material must be heated to a temperature exceeding 900°C, which has the disadvantage that the base material is limited to metals that can withstand high temperatures.

[0007]Furthermore, the conventional biological components made of the above-mentioned metals, diamond-coated metals, or ceramics all have high rigidity, so if they are used in artificial joints, artificial tooth roots, etc. that are subject to large loads, the impact load will be applied to these components. This has the disadvantage that it directly applies to the fixed part of the body, causing damage to the fixed part.

[0008]

[Problems to be Solved by the Invention] In view of the above-mentioned conventional circumstances, the present invention provides a diamond that has excellent biocompatibility, does not cause damage to the fixation site, has almost no wear or corrosion, and can withstand long-term use. The object of the present invention is to provide a coated biological component.

[0009]

[Means for Solving the Problems] In order to achieve the above object, the diamond-coated biological component of the present invention includes a metal or ceramic and a high-melting-temperature polymer compound bonded to a part of the metal or ceramic or covering the whole thereof. It consists of
Alternatively, it is characterized by comprising a base material made only of the above-mentioned polymer compound and a coating layer made of diamond or diamond-like carbon provided on all or part of the surface of the base material.

0010

[Operation] In the biological component of the present invention, a polymer compound having lower rigidity than conventionally used metals and ceramics is used for all or part of the base material on which the diamond or diamond-like carbon coating layer is to be formed. Therefore, the impact load applied to the member is dispersed, and excessive load can be prevented from being applied to the fixed part.

[0011] The polymer compound used is preferably one with low rigidity in order to disperse the impact load, and if the entire surface is not covered with a coating layer such as diamond, it must have excellent compatibility with living organisms. It is. In addition, since it is necessary to form a coating layer such as diamond on the surface by a vapor phase synthesis method such as the CVD method, the material must be able to withstand the film formation temperature.For these reasons, silicone rubber or fluorine rubber with a high melting temperature is used. Rubber etc. are preferred.

[0012] To form the coating layer made of diamond or diamond-like carbon, a conventionally known vapor phase synthesis method such as a CVD method or a PVD method is used, and a glow discharge using high frequency or the like is used as a means for turning the gas in the reaction chamber into plasma. It is preferable to use various discharge methods such as a method and an arc discharge method. In particular, the plasma CVD method or the ion beam evaporation method seems to be suitable in that the coating layer can be formed at a low temperature.

In particular, in the present invention, the film forming temperature is lowered by using a gas capable of supplying carbon atoms and hydrogen atoms as well as a gas capable of supplying halogen atoms as the raw material gas for the vapor phase synthesis method. Diamond or diamond-like carbon can be coated at a substrate temperature of 900°C. Therefore, it is now possible to use polymer compounds such as silicone rubber and fluororubber with a melting temperature of 200°C or higher as the base material, and metals and ceramics that form part of the base material can also have a melting temperature of 200°C or higher. In addition to stellite, titanium, etc., it is also possible to use aluminum, aluminum alloy, etc., which could not be used conventionally despite having a high specific strength.

Gases capable of supplying halogen atoms include halogen molecules as well as compounds containing halogen atoms in their molecules, such as paraffinic, olefinic, and fatty acids such as fluorinated methane, fluorinated ethane, trifluorinated methane, and fluorinated ethylene. It may be a halogenated organic compound such as a cyclic or aromatic compound, or a halogenated inorganic compound such as a fluorinated silane. Among these compounds, those having a large bonding force with hydrogen atoms and a small atomic radius are preferred, and fluorine compounds are particularly preferred in order to form a stable coating layer at low pressure.

Gases capable of supplying carbon atoms include aliphatic hydrocarbons such as methane, ethane, propane, ethylene and propylene, aromatic hydrocarbons such as benzene and naphthalene, or gases containing heteroatoms such as ammonia and hydrazine. There are organic compounds. In addition to hydrogen gas, gases capable of supplying hydrogen atoms include compounds containing hydrogen atoms in the molecule, such as various hydrocarbons such as the above-mentioned methane. Therefore, a compound containing both carbon atoms and hydrogen atoms in the molecule can be used as a gas capable of supplying carbon atoms and hydrogen atoms.

The thickness of the diamond or diamond-like carbon coating layer is in the range of 0.05 to 15 μm. This is because if the thickness is less than 0.05 μm, there is no effect of improving wear resistance, and if it exceeds 15 μm, there is a risk that the coating layer will peel off due to internal strain. The above-mentioned coating layer may be formed on the entire surface of the base material containing the polymer compound, or it may be formed only on areas where friction occurs.

[0017]

[Example] A base material in which silicone rubber was bonded to the joint of an artificial joint made of titanium was prepared, and a diamond coating layer with a thickness of 1 μm was formed on the entire surface of this base material using the plasma CVD method. . That is, a 1:8 mixed gas of CH4 and SiF4 is introduced into the film forming chamber as a raw material gas at a total flow rate of 20 sccm of CH4 and SiF4, and while maintaining the gas pressure in the film forming chamber at approximately 0.15 Torr, the power density is Discharge at 0.8 W/cm2 to create a plasma state, about 2
Diamond was coated on the surface of the base material made of silicone rubber and titanium, which was maintained at 50°C.

No fluorine atoms were detected in the diamond coating layer of the resulting artificial joint. This diamond-coated artificial joint was implanted in the femur of a rabbit, and when it was removed one year later, there was no wear on the joint, no problems occurred at the fixed part, and no changes such as tumors were observed in the animal.

[0019]

[Effects of the Invention] According to the present invention, since part or all of the base material is made of a polymer compound having lower rigidity than metals or ceramics, the impact load applied can be dispersed.
It is possible to provide a diamond-coated biological component that does not cause any damage to the fixation site.

[0020] Therefore, the diamond-coated biological component of the present invention has excellent biocompatibility, has almost no wear or corrosion, and can withstand long-term use, especially when subjected to impact loads such as artificial joints and artificial tooth roots. It is suitable as a biological component in which

Claims (2)

[Claims] Claim 1: A base material consisting of a metal or ceramic and a high-melting-temperature polymer compound bonded to a part of the metal or entirely covered, or consisting of only the polymer compound; 1. A diamond-coated biological component comprising a coating layer made of diamond or diamond-like carbon provided on all or part of the surface. 2. The thickness of the coating layer is 0.05 to 15 μm.
The diamond-coated biological member according to claim 1, wherein the diamond-coated biological member has a diameter of m.