JPH10179719A - Vital implant material and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a vital implant material which has high mechanical strength, bonds to bones in a short period and is stable in a living body over a long period and to provide a process for producing the same. SOLUTION: This vital implant material is constituted by forming an intermediate layer consisting of a metal Me or an alloy composed mainly of the metal Me and a surface layer inclusive of the oxide phase of the metal Me and an amorphous phase of the alkaline acid salt of the metal Me. The metal Me is Ti, Ta or Nb. The base material is recommended to be immersed into an alkaline soln. after the film consisting of the metal Me or the alloy composed mainly of the metal Me (the metal Me is Ti, Ta or Nb) is formed on the surface of the base.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a biological implant material and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, various biological implant materials have been proposed as substitutes for bone. For example, high-strength materials such as titanium metal, titanium alloy, stainless alloy, alumina, and zirconia, and bioactive materials such as apatite sintered bodies, bioactive glass, and bioactive crystallized glass are known.

[0003]

High-strength materials such as titanium metal have high mechanical strength, but require a long period of time to bond with bone. Apatite sintered bodies and bioactive glass bond to bone in a short period of time, but have low mechanical strength.
Bioactive crystallized glass bonds with bone in a short period of time, and has higher strength than apatite sintered body and bioactive glass,
The strength is not enough to be used for the load part, and the application location is limited.

An object of the present invention is to provide a bioimplant material which has high mechanical strength, bonds to bone in a short period of time, and is stable in vivo for a long period of time, and a method for producing the same.

[0005]

According to the bioimplant material of the present invention, an intermediate layer made of metal Me or an alloy mainly composed of metal Me, an oxide phase of metal Me and a metal Me A surface layer containing an amorphous phase of an alkali salt is formed, and the metal Me is Ti, Ta or Nb.

In the method for producing a biological implant material according to the present invention, the method comprises the steps of: forming a film made of metal Me or an alloy containing metal Me as a main component (metal Me is Ti, Ta or Nb) on the surface of the base material; It is characterized by being immersed in a solution.

[0007]

In the bioimplant material of the present invention, the intermediate layer is made of a metal Me made of Ti, Ta or Nb, or an element containing these metals Me as a main component and having no toxicity to the living body, for example, Na, Mg, P, Zr, Al, Sn, P
It is made of an alloy to which t, V, etc. are added. The thickness of the intermediate layer is 0.
The thickness is preferably 5 to 100 μm. If the thickness is smaller than this, it becomes difficult to form the surface layer, and if the thickness is larger, the intermediate layer is easily peeled.

The surface layer is composed of an oxide phase of metal Me and metal Me
And an amorphous phase of an alkali acid salt. Further, in addition to these phases, a crystalline phase of an alkali salt may be present. The metal Me here is the same as the metal Me of the intermediate layer, and is any of Ti, Ta, and Nb. When the concentration of the oxide phase in the surface layer gradually decreases toward the outer surface, and the concentration of the amorphous phase of the alkali salt gradually increases, the material becomes a kind of graded material, and at the interface between the surface layer and the intermediate layer. Peeling hardly occurs. Further, the thickness of the surface layer is preferably 0.01 to 10 μm. If the thickness is smaller than this, it becomes difficult to exhibit bioactivity, and if the thickness is larger, separation easily occurs in the surface layer.

The base material is not particularly limited as long as it has no harm to the living body and high mechanical strength. Considering factors such as workability, shape and mechanical strength suitable for the site to be used, metals and ceramics are used. An appropriate material can be selected from the above. Titanium metal, titanium alloy, stainless alloy, etc. can be used as the metal material, and alumina,
Zirconia or the like can be used.

When the biological implant material of the present invention having the above-mentioned structure is brought into contact with a body fluid, an amorphous form of an alkali metal salt (alkali titanate, alkali tantalate, alkali niobate) of metal Me in the surface layer is obtained. The alkali ions in the phase are exchanged for hydronium ions in the body fluid to form a gel-like hydroxide phase. In addition, the pH of the body fluid near the implant material increases due to the ion exchange. If the pH of the bodily fluid near the material is high, apatite is likely to precipitate, and if a highly reactive gel-like hydroxide phase is present on the surface of the implant material, it becomes a nucleus for apatite generation. Therefore, in the vicinity of the implant material of the present invention, an environment in which apatite is very easily precipitated is formed, and an apatite layer similar to bone is formed at an early stage, and can be bonded to bone through this layer.

[0011] The biological implant material of the present invention comprises:
Ca ions may be contained in the surface layer. Ca
When ions are contained, in addition to the above-mentioned effects of increasing the pH and forming nuclei, Ca ions are eluted into the body fluid from the material surface layer and the degree of supersaturation with respect to apatite near the material is increased, so that the material surface can be formed earlier. The apatite is generated in the first step, and as a result, the bonding speed with bone can be increased. Further, an apatite layer may be formed on the surface layer in advance.

Next, a method for producing the biological implant material of the present invention will be described.

First, a substrate formed into a desired shape is prepared. As the base material, there is no harm to the living body, the material is not particularly limited as long as it has high mechanical strength, and the workability, taking into account factors such as the shape and mechanical strength suitable for the use site, metal,
An appropriate material can be selected from ceramics and the like. As the metal, titanium metal, titanium alloy, stainless steel alloy or the like can be used, and as ceramics, alumina, zirconia or the like can be used.

Next, metal Me or metal Me is applied to the surface of the base material.
Is formed from an alloy mainly composed of Here, the metal Me is selected from any one of Ti, Ta, and Nb, and the alloy contains the metal Me as a main component and has no toxicity to living organisms, for example, Na, Mg, P, Zr, and A.
1, Sn, Pt, V and the like are added. The method for forming the coating is not particularly limited as long as it can form a uniform film on the material surface, such as sputtering, thermal spraying, and vapor deposition. The thickness of the coating is preferably from 1 to 100 μm. If the thickness is smaller than this, the surface layer is not sufficiently formed by the subsequent alkali treatment, and if it is too thick, the coating is easily cracked or peeled.

Thereafter, the substrate is immersed in an alkaline solution. Usually, there is a thin oxide film on the surface of the metal,
When the substrate is immersed in an alkaline solution, the oxide film present on the surface of the film reacts with the alkali to form an amorphous phase of an alkali metal salt of Me. In this way, a surface layer having an oxide phase of metal Me or an amorphous phase of alkali metal salt and an intermediate layer made of metal Me or an alloy containing metal Me as a main component are integrally formed on the substrate surface. You. As the alkaline solution, an aqueous solution containing Na ions, K ions, Ca ions, and the like, for example, an aqueous solution of sodium hydroxide, potassium hydroxide, calcium hydroxide, or the like, or an aqueous solution obtained by mixing them is used. Conditions such as the concentration of the alkaline solution, the temperature, and the immersion time may be determined according to the degree of formation of the film on the material surface. The concentration of the alkali ion is 0.1 to 10 M, the temperature of the solution is 25 to 90 ° C., and the immersion time is 6 to 48 hours is appropriate.

After the alkali treatment, the material surface (surface layer) may further contain Ca ions.
As a method for containing Ca ions, for example, a method of immersing in a solution or a molten salt containing Ca ions or a method of ion-implanting Ca ions can be adopted. Ca
When a solution containing ions is used, an aqueous solution containing Ca ions such as calcium chloride and calcium nitrate can be used as the solution. When a molten salt containing Ca ions is used, a calcium salt that melts at a relatively low temperature, such as calcium nitrate or calcium chloride, can be used. When Ca ions are implanted, the implantation energy and implantation amount vary depending on the composition of the base material and the state of the film, and it is necessary to select conditions that exhibit the most excellent bioactivity within a range that does not cause cracks or cracks in the film. .

After the above alkali treatment or after Ca ions are contained in the surface layer, a heat treatment is performed to enhance the stability of the surface layer, and a part of the amorphous phase of the alkali salt is removed. It may be changed to a crystalline phase of an alkali salt. In this case, the heat treatment temperature is preferably from 200 to 800 ° C. If the heat treatment temperature is lower than 200 ° C., there is no effect. If the heat treatment temperature is higher than 800 ° C., the proportion of the amorphous phase becomes too small, and the apatite forming ability is remarkably reduced. The heat treatment time is preferably 0.5 to 2 hours.

After the above-mentioned various treatments, the substrate may be immersed in a solution containing Ca ions and P ions to form an apatite layer on the surface layer in advance.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments.

(Example 1) First, 10 × 10 ×
An alumina plate having a size of 1 mm was prepared, and a coating made of titanium metal was formed on the surface thereof by sputtering. 5 ml of a 10 M NaOH aqueous solution (60 ° C.) per sample
For 24 hours, washed with distilled water, and dried. The sample thus obtained is provided on the surface of the base material with an intermediate layer of about 20 μm of titanium metal and a surface layer of about 1 μm of a titanium oxide phase and an amorphous phase of sodium titanate. Had.

This sample was immersed in a simulated body fluid adjusted to the same ion concentration as the body fluid, the period required for forming an apatite layer was investigated, and the bonding speed with the bone was evaluated.

As a result, it was confirmed that an apatite layer was formed on the entire surface of the sample within 10 days after immersion in the simulated body fluid.

(Example 2) First, 10 × 10 ×
An alumina plate having a size of 1 mm was prepared, and a film made of metal tantalum was formed on the surface thereof by sputtering. Next, alkali treatment was performed in the same manner as in Example 1 using a 0.5 M NaOH aqueous solution. The thus obtained sample has an intermediate layer of about 20 μm of metal tantalum and a surface layer of about 1 μm of a tantalum oxide phase and an amorphous phase of sodium tantalate on the substrate surface. Had.

When the time required for forming an apatite layer was examined for the obtained sample in the same manner as in Example 1, the apatite layer was formed on the entire surface of the sample within 10 days after immersion in the simulated body fluid. Was confirmed.

Example 3 First, 10 × 10 ×
A stainless steel alloy plate having a size of 1 mm was prepared, and a film made of metallic niobium was formed on the surface thereof by sputtering. Next, an alkali treatment was performed in the same manner as in Example 2. The sample obtained in this manner has an intermediate layer made of metallic niobium having a thickness of about 20 μm and a surface layer having a thickness of about 1 μm made of a niobium oxide phase and an amorphous phase of sodium niobate on the substrate surface. Had.

When the time required for forming the apatite layer was examined for the obtained sample in the same manner as in Example 1, the apatite layer was formed on the entire surface of the sample within 10 days after immersion in the simulated body fluid. Was confirmed.

Example 4 First, 10 × 10 ×
A stainless steel plate having a size of 1 mm was prepared, and a coating made of titanium metal was formed on the surface thereof by sputtering. Next, an alkali treatment was performed in the same manner as in Example 1. The sample obtained in this manner has an intermediate layer of about 20 μm of metallic titanium and a surface layer of about 1 μm of an amorphous phase of titanium titanate and sodium titanate on the surface of the substrate. Had.

When the time required for forming the apatite layer was examined for the obtained sample in the same manner as in Example 1, the apatite layer was formed on the entire surface of the sample within 10 days after immersion in the simulated body fluid. Was confirmed.

Example 5 In the same manner as in Example 1, an intermediate layer made of titanium metal and having a thickness of about 20 μm was formed on the surface of the substrate.
A surface layer having a thickness of about 1 μm comprising a titanium oxide phase and an amorphous phase of sodium titanate was formed.

Thereafter, the sample was heat-treated at 600 ° C. for 1 hour to transform a part of the amorphous phase of sodium titanate into a crystalline phase to stabilize the surface layer.

When the time required for forming the apatite layer was examined for the obtained sample in the same manner as in Example 1, the apatite layer was formed on the entire surface of the sample within 10 days after immersion in the simulated body fluid. Was confirmed.

Example 6 In the same manner as in Example 1, an intermediate layer made of metallic titanium and having a thickness of about 20 μm was formed on the surface of the base material.
A surface layer having a thickness of about 1 μm comprising a titanium oxide phase and an amorphous phase of sodium titanate was formed.

Next, it was immersed in a Ca (NO ₃ ) ₂ molten salt at 600 ° C. for 1 hour to contain Ca ions in the surface layer. Thereafter, the sample was washed with distilled water and dried to obtain a sample.

The obtained sample was examined for the period required for forming an apatite layer in the same manner as in Example 1. The apatite layer was formed on the entire surface of the sample within 7 days after immersion in the simulated body fluid. Was confirmed.

Example 7 In the same manner as in Example 1, an intermediate layer made of titanium metal and having a thickness of about 20 μm was formed on the surface of the base material.
A surface layer having a thickness of about 1 μm comprising a titanium oxide phase and an amorphous phase of sodium titanate was formed.

Next, 10 ¹⁸ ion /
A quantity of cm ² Ca ions was implanted into the surface layer of the material. Thereafter, the sample was heat-treated at 600 ° C. for 1 hour to stabilize the surface layer.

When the time required for forming an apatite layer was examined for the obtained sample in the same manner as in Example 1, the apatite layer was formed on the entire surface of the sample within 7 days after immersion in the simulated body fluid. Was confirmed.

REFERENCE EXAMPLE In the same manner as in Example 1, a film (thickness: 20 μm) made of metallic titanium was formed on the surface of the substrate.

The obtained sample was examined for the period required for forming an apatite layer in the same manner as in Example 1. As a result, no formation of an apatite layer was observed even after 4 weeks from immersion in the simulated body fluid.

[0040]

According to the bioimplant material of the present invention, an apatite layer similar to bone is formed on the surface layer at an early stage.
Combines with bone in a short time. Further, the intermediate layer and the surface layer are formed integrally with the base material, and are stable in vivo for a long period of time. Moreover, by selecting a high-strength material as the base material, a sufficiently high mechanical strength can be secured.

Further, according to the production method of the present invention, the above-mentioned biological implant material can be easily produced.

Claims (6)

[Claims] 1. A surface including, on a surface of a base material, an intermediate layer made of metal Me or an alloy containing metal Me as a main component, an oxide phase of metal Me, and an amorphous phase of an alkali metal salt of metal Me. A layer is formed, and the metal Me is Ti, Ta or N
b. a biological implant material characterized by being b. 2. The bioimplant material according to claim 1, wherein the base material is made of metal or ceramic. 3. The bioimplant material according to claim 1, wherein the surface layer contains Ca ions. 4. A method comprising forming a film made of metal Me or an alloy containing metal Me as a main component (metal Me is Ti, Ta or Nb) on the surface of the base material, and then immersing the film in an alkaline solution. A method for producing a biological implant material. 5. The method according to claim 5, wherein the substrate is made of metal or ceramic. 6. The method for producing a biological implant material according to claim 5, wherein the material surface contains Ca ions after being immersed in an alkaline solution.