Composite material, method for manufacturing the same, and biological implant

Abstract

To provide a composite material that exhibits an excellent antibacterial property and achieves a reduced elution of fluorine.SOLUTION: A composite material according to the present disclosure includes a base material and a surface layer located on a surface of the base material. The surface layer contains a compound of titanium and fluorine and a compound of titanium, fluorine, and oxygen. The abundance of the compound of titanium and fluorine in the surface layer does not exceed the abundance of the compound of titanium, fluorine, and oxygen.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a composite material, a method for manufacturing the same, and a biological implant.

Background Art

[0002] Treatment for restoring biological functions by inserting an implant device made of titanium or the like into a living body is widely performed. In these implant treatments, reducing postoperative infections has been an issue.

[0003] For example, it is known that antibacterial properties are exhibited when fluorine ions are implanted on the surface of titanium.

Summary of the Invention

[0004] The composite material according to one aspect of the present disclosure includes a base material and a surface layer located on the surface of the base material. The surface layer contains a compound of titanium and fluorine, and a compound of titanium, fluorine, and oxygen. The abundance of the compound of titanium and fluorine in the surface layer does not exceed the abundance of the compound of titanium, fluorine, and oxygen.

[0005] The method for manufacturing a composite material according to one aspect of the present disclosure includes a step of forming a composite material in which the abundance of the compound of titanium and fluorine in the surface layer located on the surface of the base material does not exceed the abundance of the compound of titanium, fluorine, and oxygen by any one of the following (a) to (d): (a) Injecting fluorine of 3×10 17 atoms / cm 2 or less into a base material containing metallic titanium; (b) Injecting fluorine into a base material containing metallic titanium and having an oxide film on the surface; (c) Reacting oxygen with a base material containing metallic titanium and into which fluorine has been injected; (d) Reacting fluorine and oxygen with a base material containing metallic titanium.

Brief Description of the Drawings

[0006]

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Mode for Carrying Out the Invention

[0007] Hereinafter, an embodiment of the present disclosure will be described in detail. Unless otherwise specified in this specification, "A to B" representing a numerical range means "A or more and B or less".

[0008] 〔1. Composite Material〕 It is said that infection can occur about six months after surgery in orthopedics and for several years after surgery in the oral region. In order to solve this problem, the present inventors have developed an antibacterial treatment technology by fluorine treatment of titanium materials, and realized a surface treatment having high antibacterial properties and excellent mechanical properties. On the other hand, the phenomenon of fluorine elution from the fluorine-treated titanium surface in an acidic environment was confirmed. The present inventors have found that it is necessary to reduce the elution of fluorine in order to achieve long-term durability that can withstand fluctuations in pH in the oral environment caused by inflammatory reactions and diet in the living body.

[0009] The composite material according to an embodiment of the present disclosure includes a base material and a surface layer located on the surface of the base material. The surface layer contains a compound of titanium and fluorine, and a compound of titanium, fluorine, and oxygen. The abundance of the compound of titanium and fluorine in the surface layer does not exceed the abundance of the compound of titanium, fluorine, and oxygen. Antibacterial properties can be imparted by containing fluorine. Here, the compound of titanium and fluorine is more likely to elute than the compound of titanium, oxygen, and fluorine. By reducing the abundance of the compound of titanium and fluorine, the elution of fluorine can be reduced. Thereby, antibacterial properties can be maintained.

[0010] In this specification, the compound of titanium and fluorine means a compound composed of titanium atoms and fluorine atoms. Further, the compound of titanium and oxygen means a compound composed of titanium atoms and oxygen atoms. The compound of titanium, fluorine, and oxygen means a compound composed of titanium atoms, fluorine atoms, and oxygen atoms. The compound of titanium, fluorine, and oxygen includes a compound having a structure in which some of the oxygen atoms in the structure composed of titanium atoms and oxygen atoms are replaced by fluorine atoms, and a compound having a structure in which fluorine atoms penetrate into the structure composed of titanium atoms and oxygen atoms.

[0011] That the abundance of the compound of titanium and fluorine in the surface layer does not exceed the abundance of the compound of titanium, fluorine, and oxygen can be confirmed, for example, by performing measurement on the surface layer by X-ray Photoelectron Spectrometry (XPS). For example, from the XPS spectrum, the ratio of the peak area of the peak attributed to the compound of titanium and fluorine to the total peak area of the peak attributed to the compound of titanium and fluorine and the peak attributed to the compound of titanium, fluorine, and oxygen is determined. This ratio may be 0.5 or less, may be less than 0.5, or may be 0.4 or less.

[0012] The compound of titanium, fluorine, and oxygen may contain at least one or more selected from the group consisting of TiOF, TiO 2-X F 2X (0 < X < 2), fluorine-substituted F-TiO2, and fluorine-penetrated F-TiO2. As TiO 2-X F 2X (0 < X < 2), for example, TiOF2 can be mentioned.

[0013] The compound of titanium and fluorine may contain TiF X (1 ≤ X ≤ 4). That is, examples of the compound of titanium and fluorine include TiF, TiF2, TiF3, TiF4, and the like.

[0014] The composite material may contain a compound of titanium and oxygen. Thereby, the elution of fluorine can be further reduced. Examples of the compound of titanium and oxygen include TiO2 and the like. The layer containing the compound of titanium and oxygen may be present on the outermost surface of the composite material. A layer containing a compound of titanium and fluorine and / or a compound of titanium, fluorine, and oxygen may be present below the layer containing the compound of titanium and oxygen.

[0015] The maximum value of the fluorine concentration in the composite material may exceed 10 atomic %, may be 20 atomic % or more, or may be 30 atomic % or more. Thereby, the antibacterial property can be improved. The maximum value of the fluorine concentration may be 80 atomic % or less, or may be 70 atomic % or less. In this specification, the fluorine concentration means the ratio of the number of fluorine atoms per unit volume to the sum of the ideal number of titanium atoms and the number of fluorine atoms per unit volume. Examples of the method for measuring the fluorine concentration include Secondary Ion Mass Spectrometry (SIMS) or XPS.

[0016] The fluorine concentration in the surface layer may be 1 ppm or more. The thickness of the surface layer may be 20 to 1100 nm, may be 30 to 1000 nm, or may be 40 to 900 nm.

[0017] The base material may contain pure titanium or a titanium alloy. Examples of pure titanium include industrial pure titanium such as C.P. grade 2 titanium. Examples of titanium alloys include Ti-6Al-4V, Ti-15Mo-5Zr-3Al, Ti-Nb, Ti-6Al-Nb, Ti-6Al-2Nb-1Ta, Ti-30Zr-Mo, Ni-Ti, Ti-3Al-2.5V, Ti-10V-2Fe-3Al, and Ti-15V-3Cr-3Al-3Sn.

[0018] The elution amount of fluorine measured by immersing the composite material in an acidic solution may be 1 μg / cm 2 ·day or less, or may be 0.5 μg / cm 2·It may be below ·day. Thereby, antibacterial property can be maintained longer. The acidic solution may be, for example, a solution with a pH of 6.0 or lower, or a solution with a pH of 5.5 to 6.0. The acidic solution may be physiological saline with adjusted pH. For example, the acidic solution may be physiological saline added with citric acid. The elution amount of fluorine can be measured, for example, by the method described in the examples.

[0019] The composite material may have antibacterial property. For example, the viable cell count evaluated by the film adhesion test using Staphylococcus aureus in accordance with JIS Z 2801 of the composite material may be significantly decreased statistically compared to untreated titanium. In this specification, untreated titanium means a titanium material that has not been subjected to fluorine implantation and oxidation treatment. Whether there is a statistically significant difference can be confirmed using various statistical methods.

[0020] The composite material may not show cytotoxicity. For example, the relative colony formation rate evaluated by the direct contact method in accordance with ISO 10993-5 of the composite material may not show a statistically significant difference compared to untreated titanium.

[0021] [2. Method for manufacturing composite material] The method for manufacturing a composite material according to an embodiment of the present disclosure includes a step of forming a composite material in which the abundance of the compound of titanium and fluorine in the surface layer located on the surface of the base material does not exceed the abundance of the compound of titanium, fluorine, and oxygen by any one of the following (a) to (d): (a) Injecting fluorine of 3×10 17 atoms / cm 2 or less into a base material containing metallic titanium; (b) Injecting fluorine into a base material containing metallic titanium and having an oxide film on the surface; (c) Reacting oxygen with a base material containing metallic titanium and into which fluorine has been injected; (d) Reacting fluorine and oxygen with a base material containing metallic titanium.

[0022] By suppressing the amount of fluorine implantation in this way, or by reacting oxygen in addition to fluorine, the amount of the compound of titanium and fluorine can be reduced compared to the amount of the compound of titanium, fluorine and oxygen. Thereby, the above-described composite material can be manufactured.

[0023] In the above (a), fluorine exceeding 5×10 16 atoms / cm 2 may be implanted. Thereby, the antibacterial property can be improved. The fluorine implantation dose in the above (b) may be 1×10 16 to 5×10 17 atoms / cm 2 or less, and may be 5×10 16 to 5×10 17 atoms / cm 2 either. The implantation energy may exceed 30 keV and be 80 keV or less.

[0024] The method of implanting fluorine into the base material may be an ion beam implantation method or a plasma-based ion implantation method. The plasma-based ion implantation method is a method of exposing the base material to a fluorine-based gas plasma. Examples of the fluorine-based gas include ArF2, CF4, NF3, C2F6, etc. The implantation energy in the plasma-based ion implantation method may be 1 to 50 keV.

[0025] Examples of the method of reacting oxygen with the base material include natural oxidation, atmospheric heat treatment, oxygen plasma treatment, oxygen ion implantation, immersion in an acid solution, and anodic oxidation. The temperature in the atmospheric heat treatment may be 100 to 800 °C, or may be 200 to 300 °C.

[0026] Anodic oxidation of titanium is a technique of applying a potential with a titanium-based material as an anode in an aqueous solution or the like to form an oxide film on the surface of the titanium-based material. In particular, by precisely controlling the thickness of the oxide film of several tens to several hundreds of nm, it is known to exhibit various colors due to the interference of light.

[0027] Fluorine and oxygen may be reacted in sequence or simultaneously. In the above (b), a step of reacting oxygen with a base material containing titanium metal may be provided. Thereby, a base material containing titanium metal and having an oxide film on the surface may be obtained. For example, the oxide film may be formed on the surface of the base material by any method of atmospheric heat treatment, oxygen plasma treatment, oxygen ion implantation, immersion in an acid solution, or anodization. In the above (c), a step of implanting fluorine into a base material containing titanium metal may be provided. Thereby, a base material containing titanium metal and into which fluorine has been implanted may be obtained.

[0028] The manufacturing method may include a step of cleaning the base material. For cleaning, for example, an organic solvent or the like may be used. Examples of the organic solvent include ethanol and acetone. Two or more organic solvents may be mixed and used. The cleaning may be ultrasonic cleaning. Further, the base material after cleaning may be vacuum dried in a desiccator. The step of cleaning the base material may be performed after reacting fluorine and / or oxygen with the base material, or may be performed before the reaction.

[0029] [3. Biological Implant] A biological implant according to an embodiment of the present disclosure includes the above-described composite material. Therefore, since elution of fluorine is reduced in the biological implant, antibacterial properties can be maintained. Examples of such biological implants include dental implants and orthopedic implants. Examples of orthopedic implants include artificial joints and spinal surgery implants. Examples of artificial joints include artificial hip joints, artificial knee joints, artificial ankle joints, artificial shoulder joints, artificial elbow joints, artificial finger joints, artificial intervertebral discs, and the like. For example, examples of artificial hip joints include femoral stems and acetabular cups. Examples of spinal surgery implants include spinal fixation instrumentation and the like.

[0030] Hereinafter, a dental implant will be described as an example. FIG. 1 is a schematic diagram of a dental implant 100 according to an embodiment of the present disclosure. The dental implant 100 includes a fixture 101, an abutment 102 attached to an end of the fixture 101, and an artificial tooth 103 attached to the fixture 101 via the abutment 102.

[0031] Each of the fixture 101, the abutment 102, and the artificial tooth 103 of the dental implant 100 may contain a composite material. As described above, the composite material can maintain antibacterial properties. Therefore, the dental implant 100 can reduce the growth of bacteria and exhibit excellent durability against brushing, repeated use, and cleaning.

[0032] Each of the fixture 101, the abutment 102, and the artificial tooth 103 may be composed only of a composite material. Further, a part of them may be composed of a composite material, and the remaining parts may be composed of materials other than the composite material. Further, at least one of the fixture 101, the abutment 102, and the artificial tooth 103 may contain a composite material, and other members may contain materials other than the composite material. For example, if the fixture 101 and the abutment 102 used in an oxygen-deficient environment contain a composite material, a reduction in the growth of anaerobic bacteria can be expected. Also, for example, if the artificial tooth 103 exposed in the oral cavity and exposed to air contains a composite material, a reduction in the growth of facultative anaerobic bacteria and aerobic bacteria can be expected. Therefore, the composite material can be applied to the fixture 101, the abutment 102, and the artificial tooth 103 according to the bacterial species for which growth is desired to be reduced and the required antibacterial performance.

[0033] The surface layer of the composite material may be located at a site where bacteria may come into contact in the dental implant 100. For example, the surface layer of the composite material may be located on the surfaces of the fixture 101, the abutment 102, and the artificial tooth 103. Alternatively, the surface layer of the composite material may be located at the site where the fixture 101, the abutment 102, and the artificial tooth 103 are joined to each other.

[0034] [4. Other applications] The above-mentioned composite material is also applicable to members other than biological implants. Since the composite material has an antibacterial function that can withstand fluctuations in the oral environment, it is also applicable to dental correction wires. In addition, the composite material can maintain its antibacterial function even after repeated washing. Therefore, for example, it is also applicable to surgical instruments, injection needles, spectacle frames, tableware (including portable tableware), water containers (e.g., drinking mouths), kitchen knives, food factory lines, toilets, warm water washing toilet seats, faucets, water supply and drainage pipes, etc.

[0035] As described above, the invention according to the present disclosure has been described based on the drawings and examples. However, the invention according to the present disclosure is not limited to the above-described embodiments. That is, the invention according to the present disclosure can be variously modified within the scope shown in the present disclosure, and embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the invention according to the present disclosure. In other words, it should be noted that those skilled in the art can easily make various deformations or modifications based on the present disclosure. Also, it should be noted that these deformations or modifications are included in the scope of the present disclosure. [Examples]

[0036] An example of the present disclosure will be described below.

[0037] [Evaluation method] [Fluoride elution amount] The composite materials of the examples or comparative examples were immersed in 10 mL of physiological saline at 37°C for 24 hours, and then the fluoride elution amount was determined by measuring the fluoride ion concentration in the physiological saline. A fluoride ion electrode was used to measure the fluoride ion concentration. In order to stably measure the fluoride ion concentration, an ion strength adjuster (citric acid buffer) was added to the physiological saline. The citric acid buffer was also added to the physiological saline in other evaluation methods shown below. The measurement conditions for the fluoride elution amount are as follows.

[0038] (Measurement conditions for fluoride elution amount) Immersion solution: 0.9% NaCl physiological saline Additive: Ion strength adjuster TISAB-11 manufactured by Toa DKK Corporation pH: 5.5 - 6.0 Immersion temperature: 37°C Immersion time: 24 hours Fluoride ion concentration measuring device: Fluoride ion electrode F-1000 manufactured by Toa DKK Corporation <Fluoride concentration> The fluoride concentration contained in the composite material was measured by SIMS and XPS. Specifically, for regions where the fluoride concentration was relatively low and below the measurement lower limit of XPS, the fluoride concentration was measured by SIMS, and for other regions, the fluoride concentration was measured by XPS. The XPS measurement was carried out at a depth of 0 - 200 nm. The SIMS measurement was carried out at a depth of 0 - 1100 nm. The fluoride concentration measurement was performed on samples before immersion in 10 mL of physiological saline at 37°C and after immersion for 24 hours. In Figures 3, 8, and 12, only the measurement results at a depth of 0 - 200 nm are shown. In Figures 3, 8, and 12, a depth of 0 nm represents the surface of the composite material.

[0039] (Measurement conditions for XPS) Analytical device: X-ray photoelectron spectrometer "PHI Quantera II" manufactured by ULVAC-PHI X-ray source: Monochromatic AlKα Sputtering ion: Ar + Accelerating voltage: 4 kV (Measurement conditions for SIMS) Analysis apparatus: Secondary ion mass spectrometer "D-SIMS 6650" manufactured by ULVAC-PHI Primary ion species: Cs + Secondary ion polarity: Negative Acceleration voltage: 2 kV Beam current: 25 nA Charge compensation: None Raster size: 400 μm Also, the thickness T of the surface layer was measured by SIMS. The surface layer was defined as the depth from the surface (depth 0 nm) of the composite material to the depth at which the fluorine concentration became 1 ppm or less.

[0040] <Fluorine bonding state> The fluorine bonding state in the composite material was analyzed by XPS narrow scan. The analysis of the fluorine bonding state was performed on the samples before immersion in 10 mL of physiological saline at 37 °C and after immersion for 24 hours.

[0041] <Antibacterial property> In accordance with JIS Z 2801, a film adhesion test was conducted using Staphylococcus aureus. For Example 1 and Comparative Example 1, the film adhesion test was performed using the samples before immersion in 10 mL of physiological saline at 37 °C and after immersion for 24 hours. For Example 3, the sample before immersion in physiological saline was used. Also, for comparison of antibacterial properties, a film adhesion test was conducted on a pure titanium test piece (untreated titanium) of the same shape without fluorine ion implantation.

[0042] <Cytotoxicity> In accordance with ISO 10993-5, the relative colony formation rate was evaluated by the direct contact method. The relative colony formation rate means the colony formation rate compared with a polyethylene sheet as a positive control. Also, for comparison of cytotoxicity, the relative colony formation rate was evaluated on a pure titanium test piece (untreated titanium) of the same shape without fluorine ion implantation. The evaluation conditions were as follows. Cells: V79 cells derived from Chinese hamster Culture period: 6 days Measurement: After staining the cells, the number of colonies was measured under a stereomicroscope.

[0043] [Comparison between Example 1 and Comparative Example 1] <Example 1> Pure titanium (C.P. grade 2 titanium) was prepared as the test piece material. The test piece material was formed into a disk-shaped sample with a diameter of 14 mm and a thickness of 1 mm. The disk-shaped sample was used as the base material. The base material was ultrasonically cleaned using ethanol and acetone, and then vacuum dried in a desiccator. Thereafter, fluorine ions were implanted into one side of the base material (one side of the disk-shaped sample) under the following conditions. Implantation method: Ion beam implantation method Implantation energy: 40 keV Implantation dose: 3×10 17 atoms / cm 2 Thereby, the composite material of Example 1 was obtained.

[0044] <Comparative Example 1> The implantation dose was changed to 5×10 17 atoms / cm 2 and the composite material of Comparative Example 1 was obtained in the same manner as in Example 1 except for this change.

[0045] <Evaluation results> Figure 2 is a graph showing the fluorine elution amounts in Example 1 and Comparative Example 1. The fluorine elution amount was 6.3 μg / cm 2 ·day in Comparative Example 1, but was 0.1 μg / cm 2 ·day in Example 1. That is, the elution of fluorine was significantly reduced in Example 1 compared to Comparative Example 1.

[0046] FIG. 3 is a graph showing the change in fluorine concentration before and after immersion in physiological saline in Example 1 and Comparative Example 1. In Comparative Example 1, the peak fluorine concentration before immersion was 63.2 atomic %, but the peak concentration after 24 hours of immersion decreased to 30.5 atomic %. On the other hand, in Example 1, the peak fluorine concentration both before and after immersion was 45.0 atomic %. That is, it was revealed that in Example 1, the fluorine concentration was maintained even after 24 hours of immersion. In addition, the thickness T of the surface layer before immersion was 740 nm in Comparative Example 1 and 1070 nm in Example 1 (not shown).

[0047] FIG. 4 is a graph showing the change in the fluorine bond state on the surface of the sample sputtered to 90 nm from the surface in physiological saline before and after immersion in physiological saline in Example 1 and Comparative Example 1. In addition to the peak at 453.9 eV attributable to Ti, which is the base material, the bond energy attributable to the fluorine compound was observed in the range of 460 to 462 eV due to fluorine ion implantation. In Comparative Example 1, the signal intensity of 461.6 eV attributable to TiF4 among the fluorine compounds was maximum before immersion. In the bond state after immersion, the peak attributable to TiF4 decreased, and the signal intensity of 460.2 eV attributable to F-TiO2 became maximum. From this change, it was inferred that TiF4 is the bond state related to fluorine elution. In Example 1, the peak attributable to F-TiO2 was maximum both before and after immersion. In this way, it became clear that the fluorine elution characteristics differ depending on the composition ratio of the fluorine compound.

[0048] Ti2p 1 / 2 We focused on fluorine compounds detected by the bond energy of TiF4. The composition ratio of these fluorine compounds was estimated from the area ratio of the peak separation before immersion. The peak area ratio of TiF4 was calculated from the peak areas of F-TiO2 (460.2 eV), TiOF2 (461.2 eV) and TiF4 (461.6 eV) according to formula 1.

[0049]

number

[0050] The results were as follows.

[0051] [Number]

[0052] From the above, it was shown that rapid elution occurred in Comparative Example 1 where the peak area ratio of TiF4 by XPS was 0.58, and elution could be reduced in Example 1 where it was 0.34. That is, in Example 1, the abundance of the compound of titanium and fluorine did not exceed the abundance of the compound of titanium, fluorine, and oxygen, and therefore it can be understood that the elution of fluorine can be reduced.

[0053] Figure 5 is a graph showing the antibacterial properties before and after immersion in physiological saline for untreated titanium, Example 1, and Comparative Example 1. The measurement results are shown as the average value of the viable cell count (CFUs) of 3 samples. The error bars in the graph indicate the standard deviation. The viable cell count before immersion was 17667 CFUs for untreated titanium, while both Comparative Example 1 and Example 1 were less than 10 CFUs (below the detection limit). The viable cell count after immersion was 340000 CFUs for untreated titanium and 5100 CFUs for Comparative Example 1, while Example 1 was less than 10 CFUs (below the detection limit).

[0054] As a result of the measurement, it was revealed that before immersion, the viable cell count was below the detection limit in both Comparative Example 1 and Example 1, and they had a high antibacterial effect. Compared with untreated titanium, both Comparative Example 1 and Example 1 statistically significantly reduced the viable cell count to less than 0.01%. Hereinafter, "statistically significant" or "statistically significant" means that there is a significant difference with a p-value of less than 5% by Student's t-test for two groups and Tukey's multiple comparison test for three or more groups. In Comparative Example 1 after immersion, a viable cell count of 5100 CFUs was observed. Compared with untreated titanium, Comparative Example 1 statistically significantly reduced the viable cell count to 1.5%. However, it was shown that Comparative Example 1 after immersion had a lower antibacterial performance compared to before immersion. On the other hand, in Example 1 after immersion, the viable cell count was below the detection limit, indicating that it maintained high antibacterial properties.

[0055] Figure 6 is a graph showing the relative colony formation rate in untreated titanium and Example 1. The measurement results are shown as the average value of the relative colony formation rates of three samples. The error bars in the graph indicate the standard deviation. The relative colony formation rate of Example 1 was 80%, and no statistically significant difference was observed compared to untreated titanium. It was revealed that Example 1 had no or very little toxicity in the test by the direct contact method.

[0056] 〔Comparison between Example 2 and Comparative Example 1〕 <Example 2> An anodic oxidation was performed on a 1 mm thick titanium alloy plate made of Ti-6Al-4V alloy until the titanium alloy plate turned blue. The anodized titanium alloy plate was formed into a disk-shaped sample with a diameter of 14 mm and a thickness of 1 mm. The disk-shaped sample was used as the base material. The base material was ultrasonically cleaned using ethanol and acetone, and then vacuum dried in a desiccator. Thereafter, fluoride ions were implanted into one side of the base material (one side of the disk-shaped sample) under the following conditions. Implantation method: Ion beam implantation method Implantation energy: 40 keV Implantation dose: 5×10 17 atoms / cm 2 As a result, the composite material of Example 2 was obtained.

[0057] <Evaluation Results> The results of comparing the composite material of Example 2 with Comparative Example 1 described above are shown below. FIG. 7 is a graph showing the amount of fluorine elution in Example 2 and Comparative Example 1. The amount of fluorine elution in Example 2 was 0.9 μg / cm 2 ·day. In Example 2, the elution of fluorine was significantly reduced compared to 6.3 μg / cm 2 ·day, which is the amount of fluorine elution in Comparative Example 1 with the same fluorine implantation dose.

[0058] FIG. 8 is a graph showing the change in fluorine concentration before and after immersion in physiological saline in Example 2 and Comparative Example 1. In Example 2, the peak concentration of fluorine before immersion was 33.4 atomic %, and the peak concentration after 24 hours of immersion was 26.5 atomic %.

[0059] FIG. 9 is a graph showing the change in the fluorine bonding state before and after immersion in physiological saline in Example 2 and Comparative Example 1. Example 2 shows the change on the surface sputtered with Ar up to 60 nm from the sample surface, and Comparative Example 1 shows the change on the surface sputtered with Ar up to 90 nm from the sample surface. In Example 2, peaks at 458.7 eV attributed to TiO2 formed by anodization and binding energies attributed to fluorine compounds in the range of 460 - 462 eV were observed. In Example 2, the intensity of 460.2 eV attributed to F-TiO2 among the fluorine compounds was the largest both before and after immersion. That is, in Example 2, it can be seen that the abundance of the compound of titanium and fluorine does not exceed the abundance of the compound of titanium, fluorine, and oxygen.

[0060] Focusing on F-TiO2 (460.2 eV), TiOF2 (461.2 eV), and TiF4 (461.6 eV), peak separation was performed, but the peaks attributable to TiOF2 and TiF4 were not separated. In Example 2, it is considered that the fluorine implanted in the oxide film mainly exists as F-TiO2.

[0061] [Comparison between Comparative Example 2 and Example 3] [Comparative Example 2] Pure titanium (C.P. grade 2 titanium) was prepared as the test piece material. The test piece material was formed into a disk-shaped sample with a diameter of 14 mm and a thickness of 1 mm. The disk-shaped sample was used as the base material. The base material was ultrasonically cleaned using ethanol and acetone, and then vacuum dried in a desiccator. Thereafter, fluorine ions were implanted into the disk-shaped sample by the plasma-based ion implantation method. The conditions for fluorine ion implantation were based on the method described in Patent No. 4568396 and were as follows. Implantation method: Plasma-based ion implantation method Fluorine source: C4F8 Implantation energy: 30 keV Thereby, the composite material of Comparative Example 2 was obtained.

[0062] [Example 3] After implanting fluorine ions in the same manner as in Comparative Example 2, the disk-shaped sample was subjected to oxidation treatment under the following conditions by the heating method. Atmosphere: Air Heating rate: 10 °C per minute Holding temperature: 300 °C Holding time: 30 minutes Cooling rate: Air cooling Thereby, the composite material of Example 3 was obtained.

[0063] [Evaluation Results] Figure 10 is a graph showing the fluorine elution amounts in Comparative Example 2 and Example 3. The fluorine elution amount in Comparative Example 2 was 5.3 μg / cm 2 ·day. The fluorine elution amount in Example 3 was 0.2 μg / cm 2 ·day. That is, the elution of fluorine was reduced in Example 3 compared to Comparative Example 2.

[0064] Figure 11 is a cross-sectional observation diagram of the composite materials in Comparative Example 2 and Example 3 taken by a transmission electron microscope. An oxide film due to natural oxidation was formed on the outermost surface of Comparative Example 2, and a fluorine layer containing fluorine was observed below it. Further, an image continuous with the titanium of the base material was observed below the fluorine layer. In Example 3, an oxide layer grown by oxidation treatment was observed on the outermost surface. A fluorine layer was observed below the oxide layer, and an image of titanium was observed below the fluorine layer.

[0065] Figure 12 is a graph showing the change in fluorine concentration before and after immersion in physiological saline in Comparative Example 2 and Example 3. In Comparative Example 2, a peak concentration of fluorine of 63.0 atomic% was observed at a position near 40 nm from the surface before immersion, but the peak concentration decreased to 10.1 atomic% after 24 hours of immersion. In Example 3, an oxide layer formed by oxidation treatment was observed in the range of 40 nm from the surface, and almost no fluorine was detected in this part. A fluorine distribution with a peak concentration of 54.7 atomic% was observed at a position near a depth of 70 nm, which is below this oxide layer. In Example 3, no significant change was observed in the fluorine distribution even after immersion. That is, it became clear that fluorine can be retained by performing oxidation treatment.

[0066] Figure 13 is a graph showing the change in fluorine bonding state before and after immersion in physiological saline in Comparative Example 2 and Example 3. It shows the change in the surface sputtered with Ar up to 50 nm in Comparative Example 2 and up to 60 nm in Example 3. In Comparative Example 2, the intensity of 461.6 eV attributed to TiF4 was the maximum. In the bonding state after immersion in Comparative Example 2, the peak attributed to TiF4 decreased and a peak of 460.2 eV attributed to F-TiO2 was confirmed. In Example 3, the peak attributed to TiF4 decreased compared to Comparative Example 2. In Example 3, no significant change was observed in the distribution ratio of the bonding state even after immersion, and it was considered that the composition was maintained.

[0067] Ti2p 1 / 2Attention was paid to the fluorine compounds detected by the binding energy. The composition ratio of these fluorine compounds was estimated from the area ratio of peak separation before immersion. The peak area ratio of TiF4 was determined from the peak areas of F-TiO2 (460.2 eV), TiOF2 (461.2 eV), and TiF4 (461.6 eV) as in Equation 1 above. The results were as follows.

[0068]

Number

[0069] From the above, Comparative Example 2 with a peak area ratio of TiF4 by XPS of 0.56 showed rapid fluorine elution as in Comparative Example 1, and in Example 3 with a peak area ratio of TiF4 of 0.38, it was shown that elution could be reduced. That is, in Example 3, the abundance of the compound of titanium and fluorine did not exceed the abundance of the compound of titanium, fluorine, and oxygen, and therefore it can be seen that fluorine elution can be reduced.

[0070] Figure 14 is a graph showing the antibacterial properties of untreated titanium and Example 3. The measurement results are shown as the average value of the viable cell count (CFUs) of three samples. The error bars in the graph indicate the standard deviation. The viable cell count was 303333 CFUs for untreated titanium, while it was 55667 CFUs for Example 3. As a result of the measurement, Example 3 significantly reduced the viable cell count by 8.5% statistically compared to untreated titanium.

[0071] Figure 15 is a graph showing the relative colony formation rate of untreated titanium and Example 3. The measurement results are shown as the average value of the relative colony formation rate of three samples. The error bars in the graph indicate the standard deviation. The relative colony formation rate of Example 3 was 78%, and no statistically significant difference was observed compared to untreated titanium. It was revealed that Example 3 has no or very little toxicity in the test by the direct contact method.

Industrial Applicability

[0072] The present disclosure can be used in the fields of biological implants and those requiring antibacterial properties.

Explanation of reference numerals

[0073] 100 Dental implant 101 Fixture 102 Abutment 103 Artificial tooth

Claims

1. A base material and a surface layer located on a surface of the base material, the surface layer includes a compound of titanium and fluorine, and a compound of titanium, fluorine, and oxygen; the amount of a compound of titanium and fluorine present in the surface layer does not exceed the amount of a compound of titanium, fluorine and oxygen present; when the surface layer is measured by X-ray photoelectron spectroscopy (XPS), the ratio of the peak area of ​​a peak assigned to a compound of titanium and fluorine to the total peak area of ​​a peak assigned to a compound of titanium and fluorine and a compound of titanium, fluorine and oxygen in the obtained XPS spectrum is 0.5 or less, The amount of fluorine dissolved was measured by immersion in an acidic solution at 1 μg / cm ２ ・A composite material having a durability of less than 100%.

2. The compound of titanium, fluorine and oxygen is TiOF, TiO ２－Ｘ F ２Ｘ (0<X<2), fluorine-substituted F-TiO ２ , fluorine interstitial type F-TiO ２ The composite material according to claim 1, comprising at least one selected from the group consisting of:

3. The compound of titanium and fluorine is TiF Ｘ 3. The composite material of claim 1 or 2, comprising: (1≦X≦4).

4. The composite material according to any one of claims 1 to 3, wherein the maximum value of the fluorine concentration is more than 10 atomic %.

5. The composite material according to any one of claims 1 to 4, wherein the surface layer has a fluorine concentration of 1 ppm or more.

6. The composite material according to any one of claims 1 to 5, wherein the surface layer has a thickness of 20 to 1100 nm.

7. A composite material according to any one of claims 1 to 6, comprising a compound of titanium and oxygen.

8. The compound of titanium and oxygen is TiO ２ 8. The composite material of claim 7, comprising:

9. The composite material according to any one of claims 1 to 8, wherein the base material comprises pure titanium or a titanium alloy.

10. A biological implant comprising the composite material according to any one of claims 1 to 9.

11. The method includes the steps of: forming a composite material in which the amount of a compound of titanium and fluorine present in a surface layer located on a surface of a base material does not exceed the amount of a compound of titanium, fluorine, and oxygen present in the surface layer by any one of the following steps (a) to (d); when the surface layer is measured by X-ray photoelectron spectroscopy (XPS), the ratio of the peak area of ​​a peak assigned to a compound of titanium and fluorine to the total peak area of ​​a peak assigned to a compound of titanium and fluorine and a compound of titanium, fluorine and oxygen in the obtained XPS spectrum is 0.5 or less, The amount of fluorine dissolved was measured by immersing the composite material in an acidic solution and found to be 1 μg / cm ２ A method for producing a composite material, the method being: (a) A base material containing metallic titanium is subjected to 3×10 １７ atoms / cm ２ Inject fluoride into the following: (b) injecting fluorine into a base material including metallic titanium and having an oxide layer on its surface; (c) reacting oxygen with a base material including metallic titanium and implanted with fluorine; (d) reacting fluorine and oxygen with a base material containing metallic titanium;

12. In the above (a), 5×10 １６ atoms / cm ２ The method of claim 11, wherein the fluorine is implanted at more than

13. The method for producing a composite material according to claim 11, wherein in (b), the oxide coating is formed on the surface by any one of atmospheric heat treatment, oxygen plasma treatment, oxygen ion implantation, immersion in an acid solution, and anodization.

14. The method for producing a composite material according to claim 11, wherein in the step (c) or (d), oxygen is reacted with the base material by any one of natural oxidation, atmospheric heat treatment, oxygen plasma treatment, oxygen ion implantation, immersion in an acid solution, and anodization.

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