JP5308754B2 - Antibacterial product, method for producing the same, and biological implant - Google Patents

Description

  The present invention relates to an antibacterial product that is used in medical supplies, household products, and the like, and has antibacterial properties even in the dark, and a method for producing the same and a biological implant.

  Antibacterial products are widely used in medical, household and industrial products. As medical supplies, for example, artificial bones and internal fixtures used for treatment of diseases, trauma, etc., or artificial joints used to reconstruct lost joint functions, used to reconstruct teeth Metal implants such as artificial roots, ceramic or plastic implants, titanium surgical instruments such as scalpels and chestnuts, titanium medical instruments such as oral spatula used during diagnostic treatment, and metal, ceramic or plastic Examples include medical equipment parts, bone-fixing hands, metal such as artificial legs, ceramic or plastic welfare tools, and the like. Examples of household items include metal, ceramic, or plastic household items that are used around water in general households such as kitchen items, toilet items, and bathroom items. In addition, examples of industrial supplies include titanium water-based piping used in houses and factories, metal, ceramic, and plastic equipment parts.

  As an example of the antibacterial product, an orthopedic implant will be described as an example. Artificial joints used in orthopedic surgery are effective treatments that can reconstruct joint function against osteoarthritis and the like, but bacteria may grow on the surface of the artificial joints and develop postoperative infections. This is because bacteria easily adhere to the artificial joint surface, and the attached bacteria form a habitat called biofilm. In this case, antibacterial drugs (antibiotics) also become ineffective, making treatment difficult. In addition, if osteomyelitis is caused, the artificial joint must be removed and reoperation is required, and sometimes the affected limb must be cut.

In recent years, research and development for imparting antibacterial properties to implants such as artificial joints have been actively conducted for the purpose of preventing this postoperative infection. As one of them, titanium oxide coating has been studied. Titanium oxide has a photocatalytic action, and can generate active oxygen upon receiving ultraviolet light in a predetermined region, thereby killing bacteria. This titanium oxide is intended to be coated on a medical device.

For example, Patent Document 1 describes a method for producing a photocatalytic material obtained by oxidizing the surface of a substrate made of titanium or a titanium alloy, and Non-Patent Document 1 describes the application of the photocatalytic material to a medical device. Has been. Patent Document 2 includes a titanium oxide-based catalyst layer and a phosphorescent material layer provided on the lower surface thereof, and this phosphorescent material layer emits excitation light including a wavelength of 200 to 40 nm and emits light after blocking the excitation light. In addition, an antibacterial product that can exhibit an antibacterial action and a deodorizing action in a dark place by activating a titanium oxide photocatalyst layer is described. Non-Patent Document 2 describes the antibacterial properties of the sprayed coating of anatase-type titanium oxide.
Japanese Patent No. 3370290 Japanese Patent Laid-Open No. 11-12114 Yoshinobu Oka et. Al., "Efficacy of titanium dioxide photocatalyst for inhibition of bacterial colonization on percutaneous implants", J. Biomed. Mater. Res. B. Appli. Biomate., On line published 3rd Apr. 2008. Kuwashima et al., “Effect of spraying conditions on antibacterial properties of TiO2 sprayed coating”, Iwate Prefectural Industrial Technology Center Research Report, No. 9 (2002)

  According to the method described in Patent Document 1, it is possible to improve the photocatalytic activity of anatase-type titanium oxide having photocatalytic activity. However, ultraviolet light with a wavelength of 380 nm is necessary to exert catalytic activity, and it exhibits antibacterial properties under the use conditions of implantable medical devices such as biological implants, that is, in vivo where ultraviolet light does not reach. Can not.

  Further, the method described in Patent Document 2 has a phosphorescent material layer on the lower surface of the titanium oxide photocatalyst layer, and attempts to obtain photocatalytic activity by the titanium oxide photocatalyst layer even in the dark by light emission from the phosphorescent material layer. It is. However, it is necessary to irradiate the phosphorescent material layer with ultraviolet light of 200 to 400 nm in advance, and it is necessary to periodically store the light, so that it is necessary to periodically store the light, so that it is surgically inserted into the living body as an implant. It is impossible.

  Non-Patent Document 3 examines the antibacterial property of the sprayed coating of anatase-type titanium oxide, but it is reported that there is almost no antibacterial property in the dark.

  As described above, according to the prior art, it is necessary to irradiate ultraviolet light directly or indirectly in order to exhibit antibacterial properties to titanium oxide, and the antibacterial properties cannot be exhibited in the dark. Was the current situation.

  Accordingly, an object of the present invention is to provide an antibacterial product using titanium oxide that can exhibit sufficient antibacterial properties even in a dark place such as in a living body, a manufacturing method thereof, and a biological implant.

  In order to solve the above-mentioned problems, the present inventors have intensively studied, and as a result, found that a sprayed coating obtained by spraying brookite-type titanium oxide powder with high-speed flame spraying exhibits antibacterial properties even in the dark, and completed the present invention. is there. That is, the antibacterial product of the present invention has a thermal spray coating formed by high-speed flame spraying of a powder mainly composed of brookite-type titanium oxide on at least a part of a substrate made of metal, ceramics or plastic. Is.

  Moreover, it is preferable that the thickness of the said sprayed coating is 1-300 micrometers.

  In addition, the method for producing an antibacterial product of the present invention is characterized in that high-speed flame spraying of powder mainly composed of brookite-type titanium oxide is performed on at least a part of a substrate made of metal, ceramics or plastic. .

  In addition, the living body implant of the present invention has a thermal spray coating formed by high-speed flame spraying of a powder mainly composed of brookite type titanium oxide on at least a part of a substrate made of metal, ceramics or plastic. Is.

  The dark place used in the present invention refers to a state in which light having a wavelength that activates a commercially available titanium oxide type photocatalyst, that is, near-ultraviolet light and visible light (electromagnetic wave having a wavelength of 300 to 830 nm) hardly exist. This state is totally dark to the human eye and cannot see anything.

  Titanium oxide is known to have anatase, rutile, and brookite crystal structures. Among these, the anatase type exhibits strong photocatalytic activity. When anatase-type titanium oxide is irradiated with ultraviolet light, active oxygen is generated by the photoexcited oxygen and its leaving holes, and exhibits antibacterial properties. When this anatase-type titanium oxide is sprayed by high-speed flame spraying, a part of the anatase-type titanium oxide transforms into a rutile-type titanium oxide, which is a stable crystal structure at high temperatures. It is lower than the antibacterial property of type titanium oxide. Of course, the sprayed coating does not exhibit antibacterial properties in the dark. In contrast, the thermal spray coating obtained by high-speed flame spraying of brookite type titanium oxide in the present invention exhibits excellent antibacterial properties even in the dark.

  Here, the high-speed flame spraying method is a technique in which coating is performed by blowing a sprayed material at a high speed of Mach 4 to 6 using a torch of about 2000 ° C. to 3000 ° C. The thermal spraying powder introduced into the high-speed flame spraying apparatus is melted by the thermal energy in the torch and the kinetic energy of high-speed conveyance, and collides with the substrate to form a thermal spray coating. The mechanism by which this sprayed coating has antibacterial properties in the dark is not clear, but even if the same brookite-type titanium oxide is sprayed by normal flame spraying (spraying temperature is about 2700 ° C, spraying speed Mach 0.6) Since it does not show antibacterial activity, structural distortion due to high kinetic energy is accumulated in the crystal when the sprayed particles collide with the substrate at high speed during high-speed flame spraying, and the catalytic activity of titanium oxide is expressed. It is considered a thing.

  According to the present invention, in order to exhibit antibacterial properties in a dark place, there is no need to provide a phosphorescent layer described in Patent Document 2, and metal ions having antibacterial properties such as silver ions and copper ions are oxidized. There is no need to add to titanium. In addition, according to the high-speed flame spraying method, a sprayed coating can be formed on a metal, ceramic or plastic base material, so that it can be widely used for applications requiring antibacterial properties.

Hereinafter, embodiments of the present invention will be described in detail.
The antibacterial product of the present invention is characterized by having a thermal spray coating formed by high-speed flame spraying of a powder mainly composed of brookite-type titanium oxide on at least a part of a substrate made of metal, ceramics or plastic. is there.

(Substrate)
The substrate used in the antibacterial product of the present invention is not particularly limited.
Examples of the metal that can be used include iron, aluminum, and alloys thereof, titanium, titanium alloys, cobalt-chromium alloys, nickel-chromium alloys, and stainless steel. As ceramics, for example, alumina, zirconia, alumina / zirconia composite ceramics, or the like can be used. Moreover, as a plastic, polyethylene, a fluorine resin, an epoxy resin, a bakelite etc. can be used, for example.

  When the antibacterial product is a biological implant, the following substrate can be used. For the base body of the biological implant, stainless alloy, cobalt-chromium alloy, titanium, titanium alloy, alumina, zirconia, or the like can be used, but titanium or titanium alloy is preferable. As the titanium alloy, an alloy to which at least one of aluminum, tin, zirconium, molybdenum, nickel, palladium, tantalum, niobium, vanadium, platinum, and the like is added can be used. Preferably, it is a Ti-6Al-4V alloy. In the present invention, the living body implant is used by being implanted at least partially in the living body, and includes an artificial tooth root, an artificial bone, an internal fixture, an artificial joint, and the like.

(Production method)
The high-speed flame spraying method is a technique for coating by using a torch of about 2000 ° C. to 3000 ° C. and blowing off the sprayed material at a high speed of Mach 4-6.
For example, it can be performed under the following thermal spraying conditions.
Thermal spray powder is introduced into a high-speed flame torch formed with a gas composition of oxygen gas 200 psi and propylene gas 150 psi with 125 psi dry air, and sprayed at a spray distance of 150-200 mm.

  In the present invention, a powder containing brookite-type titanium oxide as a main component is subjected to high-speed flame spraying. The powder containing brookite-type titanium oxide as a main component means a powder containing 51 to 100% by weight of brookite-type titanium oxide. That is, other components (hereinafter referred to as the second component) may be included, or only brookite-type titanium oxide can be used. As the second component, silicate glass, phosphate glass, soda glass, glass powder such as crystallized glass such as AW-GC, titanium and titanium alloy, cobalt-chromium alloy, stainless steel, aluminum and aluminum One or more kinds of ceramic powders such as metal powders such as alloys, alumina, zirconia, and calcium phosphate ceramics can be used. In addition, it is preferable to use a metal powder or ceramic powder having a composition close to that of the base material. The particle size of the second component is preferably 0.1 to 200 μm. This second component has an action as a binder and can reinforce the thermal spray coating to form a thick thermal spray coating.

  As the thermal spray powder of titanium oxide, one having a brookite-type crystal structure and having an average particle diameter in the range of 0.1 to 300 μm can be used. This is because if the particle size is less than 0.1 μm, the conveyance of the powder becomes unstable, which hinders the spraying process, and if it is more than 300 μm, the sprayed coating is not formed due to poor melting.

  The thickness of the thermal spray coating is not particularly limited and can be appropriately selected depending on the application. For example, it is 1 to 300 μm, more preferably 10 to 40 μm. However, sufficient antibacterial effect cannot be obtained with a film thinner than 1 μm. On the other hand, if it exceeds 300 μm, the coating film becomes brittle and the durability deteriorates.

Example 1
(Test piece preparation)
By spraying titanium oxide powder on one surface of a 50 mm × 50 mm × 2 mm pure titanium plate, a titanium oxide sprayed coating having a thickness of about 20 μm was formed. At this time, the titanium oxide powder used was titanium oxide A (brookite type titanium oxide) or titanium oxide B (rutile type titanium oxide), and the thermal spraying method used a high-speed flame spraying method and a gas flame spraying method. Table 1 shows the conditions for producing the four types of test pieces.

Here, the spraying conditions of the high-speed flame spraying method and the gas flame spraying method are as follows.
In the high-speed flame spraying, spray powder was introduced with a dry air of 125 psi into a high-speed flame torch formed with a gas composition of oxygen gas 150 psi and ethylene gas 100 psi, and sprayed at a spray distance of 150 to 200 mm. On the other hand, flame spraying was performed by introducing spray powder with dry air of 100 psi into a gas flame torch of 50 psi oxygen gas and 43 psi acetylene gas, and spraying at a spray distance of 60 to 100 mm.

(Antimicrobial test)
Antibacterial evaluation was performed in accordance with JIS Z 2801 “Antimicrobial Processed Products—Antimicrobial Test Method / Antimicrobial Effect”. However, assuming that this antibacterial member is used in vivo, bovine serum was used instead of 1/500 normal broth medium for the purpose of simulating the biological environment. The culture temperature was also changed from 35 ° C to 37 ° C. Incubation was performed in the dark for 24 hours.

(result)
The antibacterial activity value R is shown in FIG. Thereby, it turns out that only the test piece 1 which carried out the high speed flame spraying of the brookite type titanium oxide powder has the antibacterial activity which is predominantly high in a dark place compared with another test piece. Thus, the test piece 1 used in this example can exhibit antibacterial performance even in a place where light does not reach, such as in vivo, and is effective not only in preventing postoperative infection but also in treating infectious disease. It is thought that.

Example 2
In this example, ceramic was used for the substrate. That is, one side of a 25 mm diameter alumina ceramic plate having a diameter of 25 mm and a thickness of 6 mm was roughened by sandblasting, and then subjected to high-speed flame spraying under the same spraying conditions as in Example 1 to form a titanium oxide sprayed coating having a thickness of about 3 μm. Formed. Even when ceramic was used for the substrate, the same thermal spray coating as in Example 1 could be formed. Thereby, even when ceramics are used for the substrate, the same antibacterial property as in Example 1 can be expressed.

Example 3
In this example, plastics were used for the substrate. That is, after 35 mm × 15 mm of one side of a 35 mm × 15 mm × 2 mm bakelite plate was roughened by sandblasting, high-speed flame spraying was performed under the same spraying conditions as in Example 1 to form a titanium oxide sprayed coating having a thickness of about 20 μm. Even when plastics was used for the substrate, the same sprayed coating as in Example 1 could be formed. Thereby, even when plastics is used for the substrate, the same antibacterial property as in Example 1 can be exhibited.

It is a figure which shows the antibacterial activity value R in the Example of this invention.

Claims (4)

  An antibacterial product having a thermal spray coating formed by high-speed flame spraying of a powder mainly composed of brookite-type titanium oxide on at least a part of a base made of metal, ceramics or plastic.   The antibacterial product according to claim 1, wherein the sprayed coating has a thickness of 1 to 300 µm.   A method for producing an antibacterial product, wherein high-speed flame spraying of a powder mainly composed of brookite-type titanium oxide is performed on at least a part of a substrate made of metal, ceramics or plastic.   A biological implant having a thermal spray coating formed by high-speed flame spraying of a powder mainly composed of brookite-type titanium oxide on at least a part of a base made of metal, ceramics or plastic.

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