JP5728321B2 - Manufacturing method of biological implant - Google Patents

Description

This invention relates to a method for producing a bio-in plant, more particularly to a method for producing a biological implant can be firmly immobilized bioactive substance on the surface of the substrate in a straightforward easy manner.

  The method of transplanting an artificial bone to the defect part where the bone is deficient has less physical burden on the patient than the method of transplanting the patient's normal bone to the defect part. In recent years, it has been attracting attention because there are no problems in doing so.

  Bioceramics such as hydroxyapatite are particularly well known as materials for artificial bone to be transplanted, and such bioceramics are excellent artificial bone materials in that they are chemically bonded to bone. However, when considering application to a part to which a load is applied, the strength of bioceramics is weak against impact and it is considered difficult to apply to such part.

  Therefore, metal materials such as titanium alloys and cobalt chromium alloys having very high strength properties are mainly used as materials for artificial bones to be transplanted to a site where a load is applied, instead of bioceramics. However, in addition to the possibility of causing metal allergies and the like, this metal material has characteristics such as having a very large elastic modulus compared to living bones, so it was formed of a metal material. When an artificial bone is transplanted into a defect, a difference in mechanical properties between the living bone and the metal material may cause stress shielding to occur in the artificial bone, so that the surrounding bone is absorbed and becomes brittle.

  Therefore, in recent years, resins such as engineering plastics have attracted attention as materials that can solve such problems and have mechanical properties similar to those of living bones. For example, a high-density polyethylene resin has very low elasticity and is suitable for application to a part where a load is applied. However, such a resin does not directly bond to living bone, and it is necessary to impart bioactivity to an artificial bone formed of the resin. Examples of a method for imparting bioactivity to a resin having mechanical properties similar to those of living bones include, for example, a method of coating the surface of a resin molded body obtained by molding such a resin with hydroxyapatite, which is a bioactive substance, resin There has been proposed a method for imparting bioactivity by combining bioactive substances with bioactive substances.

  For example, Patent Document 1 proposes a method of forming a bioactive substance film on the surface of a resin molded body. This Patent Document 1 describes “a hard tissue filling material in which an inorganic compound film is formed on a plastic substrate and a method for producing a hard tissue filling material”. Specifically, “a hard tissue filling material characterized in that an inorganic compound having harmony with a living body is directly fixed to the surface of a base material made of an elastic plastic material without interposing a binder” (claim) Item 1), in particular, “a hard tissue filling material in which the thickness of the fixed layer of the inorganic compound is 20 to 1000 μm” (Claim 4), and “for example, plasma spraying, vacuum deposition (PVD), chemical vapor deposition (CVD), sputtering method, etc., “Method for fixing inorganic compound coating to substrate surface” (page 3, right lower column, lines 8 to 14, claim 5 etc.) and the like.

  Further, Patent Document 2 proposes a method of imparting bioactivity by combining a resin and a bioactive substance. Specifically, Patent Document 2 describes “an orthopedic composition comprising a homogeneous mixture of a biocompatible polymer and a bioactive fine particle ceramic having an average particle size of about 500 nm or less” and the like.

  Patent Document 3 describes a method for producing “apatite composite obtained by firmly fixing an apatite thin film on the surface of a substrate” (column 0008). Specifically, Patent Document 3 describes that “a base material in which an apatite nucleating agent made of calcium phosphate is immobilized on a base material surface having at least a hydrophilic surface is brought into contact with a calcium phosphate supersaturated solution. A method for producing an apatite composite "is described (claim 1).

JP-A-4-146762 Japanese translation of PCT publication No. 2004-521685 JP 2005-127716 A

  By the way, in the method of forming an inorganic compound film on the surface of a base material using plasma spraying method or sputtering described in Patent Document 1, the inorganic compound film becomes too thick, cracking of the film, peeling of the film, etc. In addition, there is a concern that an expensive device is required and the manufacturing cost is increased.

  In addition, in the method for imparting bioactivity by combining the thermoplastic resin and the bioactive substance described in Patent Document 2, the bioactive substance is combined with the base material, so that the mechanical properties are similar to those of living bone. The features of the thermoplastic resin itself may be impaired, and the advantages of using the thermoplastic resin may be lost.

  Furthermore, in the manufacturing method described in Patent Document 3, there are problems in that a pretreatment such as process complexity and hydrophilization of the substrate is required.

Object of this invention is to provide a method for producing an implant that can be firmly immobilized bioactive substance on the surface of the substrate in a straightforward easy manner, there.

  The present invention relates to a method for manufacturing a biological implant in which a biologically active substance is immobilized on the surface of a substrate made of a thermoplastic resin, the substrate having the biologically active substance disposed on the surface. It has the process of heating to the glass transition temperature of thermoplastic resin -30 degreeC or more and the heating temperature below melting | fusing point, It is characterized by the above-mentioned.

  The method for producing a bioimplant according to the present invention includes a step of heating a base material on which a bioactive substance is disposed to a heating temperature of a glass transition temperature of a thermoplastic resin of −30 ° C. or higher and lower than a melting point. Despite being a simple method without the need for special equipment, the bioactive substance is dispersed or dispersed on the surface of the base material, that is, in a state where no film peeling should occur because no film is formed. It can be firmly fixed.

Moreover, this biological implant manufacturing method Ru produced in the living body implant according to the invention (hereinafter sometimes referred to as "an implant according to the invention".) Exerts without impairing the mechanical characteristics of the base material In addition, the present invention can be applied to a part to which a load is applied, and the bioactive substance is not easily detached from the base material, and exhibits high binding ability with living bone (in this invention, living bone includes living teeth). The reason why the living body implant according to the present invention can be applied to a part to which a load is applied is that the base material of the living body implant according to the present invention is formed of a material having similar mechanical characteristics to that of a living bone. Unlike metal, it does not cause stress shielding when applied to, and has almost no adverse effects on surrounding living bones such as bone loss and bone density reduction.

FIG. 1 is a scanning electron micrograph when the surface of a solid substrate after pure water cleaning in Example 1 is observed. FIG. 2 is a scanning electron micrograph when the surface of the biological implant produced in Example 1 is observed. FIG. 3 is a scanning electron micrograph when the surface of the living body implant manufactured in Example 1 is irradiated with ultrasonic waves. FIG. 4 is a scanning electron micrograph when the surface of the biological implant produced in Example 2 is observed. FIG. 5 is a scanning electron micrograph when the surface of the living body implant manufactured in Example 2 is observed after being irradiated with ultrasonic waves. FIG. 6 is a scanning electron micrograph when the surface of the biological implant produced in Example 5 is observed. FIG. 7 is a scanning electron micrograph when the surface of the living body implant manufactured in Example 5 after being irradiated with ultrasonic waves is observed. FIG. 8 is a scanning electron micrograph when the surface of the biological implant produced in Example 6 is observed. FIG. 9 is a scanning electron micrograph when the surface of the living body implant manufactured in Example 6 is observed after being irradiated with ultrasonic waves. FIG. 10 is a scanning electron micrograph when the surface of the biological implant produced in Example 7 is observed. FIG. 11 is a scanning electron micrograph when the surface of the living body implant manufactured in Example 7 is observed after being irradiated with ultrasonic waves. FIG. 12 is a scanning electron micrograph when the surface of the biological implant produced in Example 8 is observed. FIG. 13 is a scanning electron micrograph when the surface of the living body implant manufactured in Example 8 is irradiated with ultrasonic waves. FIG. 14 is a scanning electron micrograph when the surface of the biological implant produced in Example 9 is observed. FIG. 15 is a scanning electron micrograph when the surface of the living body implant manufactured in Example 9 is irradiated with ultrasonic waves. FIG. 16 is a scanning electron micrograph when the surface of the living body implant manufactured in Example 10 after being irradiated with ultrasonic waves is observed. FIG. 17 is a scanning electron micrograph when the surface of the biological implant produced in Comparative Example 1 is observed. 18 is a scanning electron micrograph when the surface of the living body implant manufactured in Comparative Example 1 is irradiated with ultrasonic waves. FIG. 19 is a scanning electron micrograph when the surface of the biological implant produced in Comparative Example 2 is observed. FIG. 20 is a scanning electron micrograph when the surface of the living body implant manufactured in Comparative Example 2 is observed after being irradiated with ultrasonic waves. FIG. 21 is a scanning electron micrograph when a fresh section of the living body implant of Example 1 is observed. FIG. 22 is a scanning electron micrograph when the surface of the surface foamed substrate used in Examples 7 to 9 is observed at a low magnification (× 300). FIG. 23 is a scanning electron micrograph when the surface of the surface foamed substrate used in Examples 7 to 9 is observed at a high magnification (× 10000).

  The biological implant according to the present invention has a base material made of a thermoplastic resin and a bioactive substance disposed on the surface thereof. The base material may be a solid base material (sometimes referred to as “substantial part”) substantially solidly formed of a thermoplastic resin, and a porous structure disposed or laminated on the outer surface of the solid base material. It may be a multilayer substrate having a surface layer. Examples of the multilayer substrate having a surface layer having a porous structure include a multilayer substrate having a surface layer having a porous structure having pores having a pore diameter of 10 μm or less opened on the surface (in this invention, “microporous substrate”). And a multi-layer base having a porous surface foam layer having pores having different sizes of small pores having a pore diameter of 10 μm or less and large pores having a pore diameter of 10 to 200 μm. Materials (sometimes referred to as “surface foam substrate” in this invention), and the like. For example, when the bioimplant according to the present invention requires a high strength, a solid substrate is adopted, whereas when a rapid biocompatibility and a high biobinding force are required, a microporous substrate or A multilayer substrate such as a surface foam substrate is employed.

  In the present invention, the “surface” of the base material is a contour surface that forms the outer shape of the base material. Specifically, when the base material is a solid base material, it is the outer surface of the base material. In the case of a layer substrate, it is the surface of the surface layer and the inner surface of the porous structure in the surface layer. In addition, in this invention, it is preferable that the bioactive substance is arrange | positioned only on the surface of a base material at the point which can maintain the mechanical characteristic of a base material. Here, “arranged only on the surface of the substrate” includes the case where the bioactive substance is unavoidably present in addition to the case where no bioactive substance is present inside.

  The biological implant according to the present invention is immobilized in a state where the bioactive substance is dispersed or scattered on the surface of the base material. Thus, in the biological implant according to the present invention, the bioactive substance is immobilized so as to be dispersed or scattered in a state of being placed on the surface of the base material without penetrating into the base material.

In the bioimplant according to the present invention, it is preferable that the bioactive substance immobilized on the surface of the base material, particularly the fixing force of the particles is strong. Evaluation is made based on the area ratio of covering the surface of the substrate with the bioactive substance immobilized without falling off from the surface of the material (sometimes referred to as surface coverage in this invention). The immobilization evaluation of the bioactive substance was performed by measuring the surface of the bioactive substance particles remaining in the observation area of 100 μm ² when the surface of the bioimplant according to the present invention was observed before and after being irradiated with 200 W ultrasonic waves in water for 10 minutes. Evaluation is based on the coverage (area%). Specifically, first, the surface of the biological implant according to the present invention is binarized by, for example, binarizing a micrograph taken by observing a plurality of, for example, three 100 μm ² regions at a magnification of 10,000 times, for example, with a scanning electron microscope or the like. Then, the total area of the bioactive substances arranged on the surface of the substrate is calculated, and the total area is divided by the surface area of 100 μm ² of the observation region to calculate the surface coverage (area%) before irradiation. As the surface coverage (area%) before irradiation, an arithmetic average value of a plurality of measurement points can be used. Next, this living body implant is immersed in pure water at 25 ° C. (100 mL per volume of living body implant 150 mm ³ ) in an unstirred state, and ultrasonic waves with a frequency of 38 kHz and an output of 200 W are passed through the pure water for 10 minutes. After irradiation, the biological implant is removed from the pure water and dried by heating at 80 ° C. Next, the surface of the biological implant is similarly observed with a scanning electron microscope or the like, and the microscopic photograph taken by observing the same number of, for example, three points of 100 μm ² is binarized, for example. Calculate the total area of the material, then the surface coverage (area%) after irradiation. As the surface coverage (area%) after irradiation, an arithmetic average value of a plurality of measurement points can be used. The immobilization force of the bioactive substance is evaluated based on whether or not the surface coverage (area%) after irradiation calculated in this way is 20% or more with respect to the surface coverage (area%) before irradiation. To do. In this evaluation method, the observation region before and after the ultrasonic irradiation may be the same region or a different region, and is arbitrarily selected.

  As described above, the biological implant according to the present invention has a surface coverage of the base material by the bioactive substance arranged on the surface of the base material with respect to the surface coverage before irradiation when 200 W ultrasonic waves are irradiated for 10 minutes. Thus, with the fixing force remaining so that the surface coverage after irradiation becomes 20% or more, the bioactive substance is immobilized in a dispersed or scattered state on the surface of the substrate. When the bioactive substance is immobilized in this way, the bioactive substance does not substantially exist inside the base material, does not form a complex with the base material, and does not cover the base material. Without impairing the mechanical properties of the thermoplastic resin, that is, the base material, the living body implant according to the present invention also exhibits the same mechanical properties as the thermoplastic resin. Therefore, unlike the metal, the living body implant according to the present invention does not cause stress shielding and hardly has an adverse effect on surrounding living bones such as bone loss and bone density reduction. It can also be applied to sites. In addition, when the bioactive substance is immobilized as described above, the bioactive substance does not cover the base material, so there is no problem specific to the coating such as cracking or peeling. It is difficult to fall off and exhibits high binding ability with living bones.

  The bioactive substance of the bioimplant according to the present invention is a surface coating after irradiation with the bioactive substance in that the bioactive substance exhibits a higher and quicker binding ability with the living bone without further detachment from the substrate. The rate (area%) is preferably 25% or more, particularly preferably 30% or more with respect to the surface coverage (area%) before irradiation. The upper limit of the surface coverage (area%) after irradiation should ideally match 100%, that is, the surface coverage (area%) before irradiation, but in reality it is about 50%. In this invention, the surface coverage (area%) after irradiation may be 20% or more of the surface coverage (area%) before irradiation in at least one of a plurality of observation regions. The surface coverage (area%) after irradiation in the two or more observation regions is preferably 20% or more in that the bone is more firmly and rapidly bonded, and the average value of the plurality of observation regions is The surface coverage (area%) is preferably 20% or more.

  A biological implant which is an example of the biological implant according to the present invention will be described below. This biological implant has a solid base material and a bioactive substance, and the bioactive substance is immobilized on the surface of the solid base material.

  The solid base material is substantially solid made of a thermoplastic resin, and the shape, size, and the like thereof are appropriately selected according to the portion to be applied. The thermoplastic resin that forms the solid base material has mechanical characteristics similar to or similar to those of living bones, but it can be applied not only to parts where no load is applied but also to parts where load is applied. It is preferable. Therefore, the solid base material also has mechanical properties similar to or close to those of living bones like the thermoplastic resin. Examples of mechanical properties that are similar to or approximate to living bone include an elastic modulus of 10 to 50 GPa, a bending strength of 100 MPa or more, and the thermoplastic resin only needs to have at least one of these properties.

  Examples of such a thermoplastic resin include a thermoplastic resin in which fibers are not mixed (also referred to as a fiber-free thermoplastic resin), a fiber reinforced thermoplastic resin in which fibers are mixed, and the like. Examples of the fiber-free thermoplastic resin include polyamide, polyacetal, polycarbonate, polyphenylene ether, modified polyphenylene ether, polyester, polyphenylin oxide, polybutylene terephthalate, polyethylene terephthalate, polysulfone, syndiotactic polystyrene, polyethersulfone, and polyphenylene. Engineering plastics such as sulfide, polyarylate, polyetherimide, polyetheretherketone, polyamideimide, polyimide, fluorine resin, ethylene vinyl alcohol copolymer, polymethylpentene, diallyl phthalate resin, polyoxymethylene, polytetrafluoroethylene Is mentioned.

  Examples of the thermoplastic resin used as the matrix of the fiber reinforced thermoplastic resin include, in addition to the engineering plastic, polyethylene, polyvinyl chloride, polypropylene, EVA resin, EEA resin, 4-methylpentene-1 resin, ABS resin, AS, and the like. Resin, ACS resin, methyl methacrylate resin, ethylene vinyl chloride copolymer, propylene vinyl chloride copolymer, vinylidene chloride resin, polyvinyl alcohol, polyvinyl formal, poly (vinyl acetoacetal), poly (fluorinated ethylene propylene), poly (trifluorotrifluoroethylene) Methacrylic resin, noryl resin, polyallyl ether ketone, polyketone sulfide, polystyrene, isophthalic acid resin, polyurethane, alkylbenzene resin, polydiphenyl ether and the like.

  Examples of the fibers contained in the fiber reinforced thermoplastic resin include carbon fibers including carbon nanotubes, glass fibers, ceramic fibers, metal fibers, and organic fibers. Examples of the glass fibers include fibrous materials of borosilicate glass (E glass), fibrous materials of high strength glass (S glass), fibrous materials of high elasticity glass (YM-31A glass), and the like. Examples of the ceramic fiber include a silicon carbide fiber, a silicon nitride fiber, an alumina fiber, a potassium titanate fiber, a boron carbide fiber, a magnesium oxide fiber, Examples include zinc oxide fibrous materials, aluminum borate fibrous materials, boron fibrous materials, etc. Examples of the metal fibers include tungsten fibrous materials, molybdenum fibrous materials, and stainless steel fibrous materials. Steel fiber, tantalum fiber, and the like. Examples of the organic fiber include, for example, polyvinyl alcohol fiber, polyamide fiber, polyethylene, and the like. Fibrous material terephthalate, fibrous material of a polyester, a fibrous material aramid, and the like. The fiber can be used alone or in a mixture of two or more.

  Of these, the polyether resin is particularly preferably polyether ether ketone (PEEK), which has mechanical properties close to those of living bones and high biocompatibility.

  Solid base materials include thermoplastics, light stabilizers such as antistatic agents, antioxidants, hindered amine compounds, lubricants, antiblocking agents, UV absorbers, inorganic fillers, and pigments as necessary. It may contain various additives such as coloring agents.

The bioactive substance is fixed on the surface of the solid substrate. This bioactive substance is particularly limited as long as it has a high affinity with a living body and has a property of chemically reacting with bone tissue including living bone or tooth tissue including living teeth (hereinafter referred to as bone tissue). For example, a calcium phosphate compound, bioactive glass, calcium carbonate, etc. are mentioned. Examples of calcium phosphate compounds include calcium hydrogen phosphate, calcium hydrogen phosphate hydrate, calcium dihydrogen phosphate, calcium dihydrogen phosphate hydrate, α-type tricalcium phosphate, β-type tricalcium phosphate, dolomite , Tetracalcium phosphate, octacalcium phosphate, hydroxyapatite, fluorapatite, carbonate apatite, and chlorapatite. Bioactive glass comprises bioglass, crystallized glass (also called glass-ceramics.), Etc., as a bioglass, for _{example, SiO 2 -CaO-Na 2 O} -P 2 O 5 based _glass, SiO 2 -CaO- Na ₂ O—P ₂ O ₅ —K ₂ O—MgO-based glass, SiO ₂ —CaO—Al ₂ O ₃ —P ₂ O ₅ -based glass, and the like can be mentioned. Examples of crystallized glass include SiO _{2. -CaO-MgO-P} 2 _{O 5} based glass (also called apatite wollastonite crystallized glass.), _{and, CaO-Al 2 O 3 -P} 2 O 5 based glass. These calcium phosphate compounds, bioglass, and crystallized glass are described in, for example, “Chemical Handbook Applied Chemistry 6th Edition” (The Chemical Society of Japan, published on January 30, 2003, Maruzen Co., Ltd.), “Development of Bioceramics and “Clinical” (edited by Hideki Aoki et al., April 10, 1987, Quintessence Publishing Co., Ltd.) and the like.

  Among these, the bioactive substance is preferably at least one of a calcium phosphate compound and bioactive glass from the viewpoint of excellent bioactivity. Furthermore, the bioactive substance is similar in composition, structure and properties to the living bone, and is stable in the body environment. Hydroxyapatite or tricalcium phosphate is particularly preferred in that it is excellent and does not show remarkable solubility in the body.

  This bioactive substance may be highly crystalline, low crystalline or non-crystalline, and may have a plurality of crystallinity. The solubility of the bioactive substance, that is, the biobinding property can be adjusted by the crystallinity of the bioactive substance immobilized on the surface of the solid substrate. For example, if the crystallinity of the bioactive substance is highly crystalline, the bioactive substance has a low dissolution rate and is fixed to a solid substrate for a long period of time. it can. On the other hand, if the crystallinity of the bioactive substance is amorphous, the bioactive substance has a high dissolution rate, and the living implant and the living bone are quickly bonded. Therefore, in the present invention, the crystallinity of the bioactive substance can be appropriately selected according to the formation rate of the living bone.

  Here, the low crystallinity means a state in which the degree of crystal development is low. Taking hydroxyapatite as an example, in powder X-ray diffraction measurement, 2θ = 25.878 ° and interplanar spacing (d value) = 3.44 mm. A half-width in a diffraction line is 0.2 ° or more, and high crystallinity means a state in which the degree of crystal growth is high. In the case of hydroxyapatite, the half-width is less than 0.2 °. Means things. Since the hydroxyapatite of living bone has low crystallinity (half-value width under the above conditions: about 0.4 °), the same crystallinity (half-value width under the same conditions: 0.2 to 1.0) °) or by making it non-crystalline, the living implant and the living bone are quickly bonded. Further, the non-crystalline property means that a broad peak is observed in the vicinity of 2θ = 30 ° in powder X-ray diffraction measurement, and it has a characteristic that it becomes hydroxyapatite by firing at a temperature of 500 ° C. or higher.

  The crystallinity of the bioactive substance can be appropriately adjusted by the “process for arranging the bioactive substance” described later. For example, when a process of immersing the base material in a suspension of the bioactive substance is employed. Depending on the crystallinity of the bioactive substance to be suspended, on the other hand, when adopting a step of alternately immersing the base material in a solution containing calcium ions and a solution containing phosphate ions, the composition components of these solutions Can be adjusted by the kind, composition ratio and / or immersion temperature.

The shape of the highly crystalline or low crystalline bioactive substance may be granular, granular or powder that can be dispersed or scattered on the surface of the solid substrate, and may be an aggregate. Examples thereof include a spherical shape, an elliptical spherical shape, a needle shape, a columnar shape, a rod shape, a plate shape, and a polygonal shape. The particle diameter of the bioactive substance immobilized on the solid base material is not particularly limited as long as it is smaller than an observation region (100 μm ² ) described later, but is more firmly immobilized on the surface of the solid base material. For example, the thickness is preferably 0.001 to 10 μm, and particularly preferably 0.01 to 5 μm. In addition, “particle” and “particle diameter” described in the present specification are “primary particle” and “primary particle diameter”, respectively, unless otherwise specified, and are fixed to a solid substrate. In the case where the bioactive substance is an aggregate, it is the primary particle that is the minimum unit constituting the aggregate and the diameter thereof. The particle diameter can be calculated by the intercept method. Specifically, a photograph can be taken with a scanning electron microscope, a straight line intersecting at least 15 particles can be drawn, and the average value of the length of the portion where the straight line and the particle intersect can be calculated. If the shape is other than spherical particles, the area-converted diameter is calculated.

  This biological implant is immobilized in a state where the particles of the bioactive substance are dispersed or scattered on the surface of the solid substrate. The surface on which the particles of the bioactive substance are immobilized is the outer surface of the solid substrate as described above. The particles of the bioactive substance are immobilized in a state of being dispersed or scattered on the surface of the solid base material. Therefore, since the particles of the bioactive substance are scattered and attached to the surface forming the outline of the solid base material, the majority of the scattered particles are embedded in the solid base material. Exposed without being. Thus, when the particles of the bioactive substance that are mostly exposed are fixed in a dispersed or scattered state, the living implant and the living bone are quickly and uniformly bonded. Although the bioactive substance particles are in a dispersed or scattered state, it does not completely exclude the presence of aggregates of multiple particles, and it is sufficient that most of the bioactive substance particles are dispersed or scattered. , A part of them may be aggregated.

  In bio-implants, the particles of the bioactive substance are fixed in a dispersed or scattered state and do not form a film. Therefore, if the coverage of the particles covering the surface of the solid substrate is less than 100% It is not particularly limited as long as it satisfies the immobilization evaluation. Further, the volume ratio of the bioactive substance particles to the solid base material is not particularly limited as long as the immobilization evaluation is satisfied.

The immobilization force of the particles of the bioactive substance immobilized on the surface of the solid base material satisfies the immobilization evaluation. Specifically, when 200 W ultrasonic waves are irradiated for 10 minutes in the bioimplant. Furthermore, the surface coverage (area) of 20% or more with respect to the surface coverage (area%) of the bioactive substance placed on the surface of the solid substrate before irradiating the ultrasonic wave in the observation area of 100 μm ² %), The particles of the bioactive substance are immobilized in a state of being dispersed or scattered only on the surface of the solid substrate.

  The immobilization force of the bioactive substance can be adjusted by, for example, the contact state between the bioactive substance and the solid base material. As an example, for example, as described later, the thermoplastic resin in which the bioactive substance is disposed is used. It can be adjusted by the heating temperature, the heating time and the like.

  This biological implant may be manufactured by a manufacturing method in which a bioactive substance is immobilized on the surface of a solid base material so as to satisfy the above-described immobilization evaluation. Examples thereof include a method for producing a biological implant. Therefore, this living body implant is manufactured by the manufacturing method of the living body implant according to the present invention, and is firmly fixed in a state where the bioactive substance is dispersed or scattered on the surface of the solid base material so as to satisfy the above-described fixing evaluation. ing. This manufacturing method includes a step of heating the substrate to a heating temperature lower than the melting point of the glass transition temperature of the thermoplastic resin at −30 ° C. or higher.

  A biological implant which is another example of the biological implant according to the present invention will be described below. This bioimplant has a microporous substrate and a bioactive substance, and the bioactive substance is immobilized on the surface of the surface layer of the microporous substrate. The bioactive substance is basically the same as the bioactive substance of the biological implant.

  The microporous substrate is a surface layer of a porous structure having a solid part and a pore having a pore diameter of 10 μm or less that is arranged or laminated on the surface of the solid part and opened on the surface (in this invention, “microsurface layer” ”). That is, the entire microporous substrate is covered with the micro surface layer. The substantial part is basically the same as the solid base material of the biological implant except that the biologically active substance is not substantially immobilized on the surface thereof. In this microporous substrate, the microsurface layer may be disposed on the entire surface of the substantial part, and only on the surface that needs to be bonded to the living bone, that is, the microsurface layer on a part of the surface of the substantial part. May be arranged.

  The micro surface layer is disposed on the substantial part, and is formed in a porous structure with the same thermoplastic resin as the substantial part. The porous structure of the micro surface layer is sufficient if it has a large number of pores that open to the surface of the micro surface layer and pores formed inside the micro surface layer. It is preferable to form a structure. This is because if the micro surface layer has a porous structure, proteins and the like are likely to adhere in the living body, providing a suitable scaffold for cells forming bone.

  As the pore diameter of the pores in the porous structure in the micro surface layer, the pore diameter opened to the surface of the surface layer (hereinafter referred to as the opening diameter) by a measuring method using a scanning electron microscope described later is 10 μm or less. It is preferable that the thickness is 5 μm or less. If the micro surface layer has a multilayer structure, the bond between the living body implant and the living bone becomes stronger, but if the opening diameter is 10 μm or less, the mechanical properties of the living body implant, particularly the micro surface layer, are greatly reduced. Therefore, the living body implant and the living bone can be bonded more firmly. Moreover, it is preferable that the pore diameter (henceforth an internal diameter) formed in the inside of a surface layer by a measuring method using the scanning electron microscope mentioned later is 0.1-10 micrometers. The reason is that proteins and the like are easily attached in the living body, which is a suitable scaffold for cells forming bone. Furthermore, it is preferable that the long diameter of the communication hole by the measuring method using the scanning electron microscope mentioned later is 10 micrometers or less. The reason is the same as the opening diameter.

  Further, the porosity of pores opening on the surface of the surface layer (hereinafter referred to as “opening porosity”) is preferably 10 to 90%, particularly preferably 20 to 80%, by a measurement method using a scanning electron microscope described later. . If the open porosity is in the range of 10 to 90%, a space for forming a new living bone is sufficiently secured, so that a new living bone is formed so as to fill the space, and the communication hole is formed. In addition, a new living bone is formed, and the bond between the living implant and the living bone is further strengthened. 10 to 90% is preferable and 20 to 80% is particularly preferable as the porosity of the cross section of the surface layer (hereinafter referred to as cross section porosity) by a measurement method using a scanning electron microscope described later. The reason is the same as the open porosity.

  The opening diameter, the internal diameter, the long diameter of the communication hole, the opening porosity, and the cross-sectional porosity can be calculated by ordinary methods. For example, as a calculation method in the present invention, the opening diameter, the internal diameter, and the long diameter of the communication hole are obtained by observing the surface and the cross section of the surface layer with a scanning electron microscope, and the pore diameter and the communication hole in the photograph of the surface and the cross section of the surface layer. It can be determined by measuring the major axis. In addition, the porosity is binarized into pores and other portions using image analysis software using photographs taken with a scanning electron microscope of the surface and cross section of the surface layer. Next, the porosity can be determined by calculating the ratio of the area of the pores to the area of the entire photograph. As another method, an opening diameter, an internal diameter, an opening porosity, and a cross-sectional porosity can be calculated | required using a mercury porosimeter.

  The thickness of the micro surface layer having such a porous structure is preferably from 1 to 1000 μm, particularly preferably from 20 to 200 μm. When the thickness of the micro surface layer is within the above range, the living body implant and the living bone can be bonded more firmly without greatly reducing the mechanical properties of the living body implant, particularly the micro surface layer.

  The thickness of the micro surface layer, the opening diameter, the internal diameter, the long diameter of the communication hole, the opening porosity, and the cross-sectional porosity can be adjusted by conditions in the micro surface layer forming process. For example, when the surface layer is formed by immersing a solid body made of a thermoplastic resin in a corrosive solution such as concentrated sulfuric acid, the thickness of the micro surface layer is determined by the time for immersing the solid body in the corrosive solution and / or It can be adjusted according to the temperature, and the opening diameter, internal diameter, long diameter of the communication hole, opening porosity and cross-sectional porosity are determined depending on the type of cleaning solution to be cleaned after the solid is immersed in the corrosive solution, the cleaning temperature and It can be adjusted by at least one of the washing times. In addition, when forming a micro surface layer using a low molecular water-soluble organic substance or a low molecular water-soluble inorganic substance, the thickness of the micro surface layer, the opening diameter, the internal diameter, the long diameter of the communication hole, the opening porosity and The cross-sectional porosity can be adjusted according to the type, amount of use, etc. of the low-molecular water-soluble organic substance or low-molecular water-soluble inorganic substance.

  The bioactive substance is immobilized in a dispersed or scattered state on the surface of the micro surface layer, that is, the outer surface of the micro surface layer and the inner surface of the pores of the porous structure. That is, the particles of the bioactive substance are adhering to the surface forming the outline of the micro surface layer and the inner surface of the pores in a state of being loaded or placed in a scattered manner. Is exposed without being embedded in the micro surface layer. Thus, when the particles of the bioactive substance that are mostly exposed are fixed in a dispersed or scattered state, the living implant and the living bone are quickly and uniformly bonded. The state in which the bioactive substance is dispersed or scattered is as described for the bioimplant.

The immobilization force of the particles of the bioactive substance immobilized on the surface of the micro surface layer satisfies the immobilization evaluation. Specifically, when 200 W ultrasonic waves are irradiated for 10 minutes in a biological implant. The surface coverage (area%) of 20% or more with respect to the surface coverage (area%) of the bioactive substance placed on the surface of the micro surface layer before irradiating ultrasonic waves in the observation area of 100 μm ² The particles of the bioactive substance are immobilized in a state of being dispersed or scattered only on the surface of the micro surface layer of the microporous substrate. The method for adjusting the immobilization force of the bioactive substance is as described above. A biological implant in which a bioactive substance is immobilized on the surface of the micro surface layer so as to satisfy the above-described immobilization evaluation is produced by, for example, a method for producing a biological implant according to the present invention described later.

  A biological implant that is another example of the biological implant according to the present invention will be described below. This biological implant has a surface foam base material and a bioactive substance, and the bioactive substance is immobilized on the surface of the surface layer of the surface foam base material. The bioactive substance is basically the same as the bioactive substance of the biological implant.

  The surface-foamed substrate has solid solid portions and pores that are arranged or laminated on the surface of the substantial portion and have different sizes of small pores having a pore diameter of 10 μm or less and large pores having a pore diameter of 10 to 200 μm. And having a porous surface layer (sometimes referred to as “surface foam layer” in the present invention). That is, the entire surface foamed substrate is covered with the surface foamed layer. The substantial part is basically the same as the solid base material of the biological implant except that the biologically active substance is not substantially immobilized on the surface thereof. The surface foamed substrate may have a surface foamed layer disposed on the entire surface of the substantial part, and only on the surface that needs to be bonded to the living bone, that is, the surface foamed layer on a part of the surface of the substantial part. May be arranged.

  The surface foam layer is disposed on the substantial part, and is formed in a porous structure with the same thermoplastic resin as the substantial part. The porous structure of the surface foamed layer only needs to have a large number of pores of different sizes opening on the surface of the surface foamed layer and inside the surface foamed layer, and a plurality of pores communicate with each other. A network structure is preferably formed by the communication holes. When the surface foamed layer has such a porous structure, the so-called anchor effect strengthens the bond with the living implant bone. Specifically, when a living body implant is embedded in a living body, when the bonding with living bone progresses starting from the bioactive substance contained in the surface foaming layer, there are many fine spaces in the surface foaming layer. In this space, new bone can be easily generated. Therefore, the bonding between the living body implant and the living bone proceeds inside the pores away from the surface foam layer and can spread and bond in a dendritic manner to the inside of the surface foam layer. The bond between the implant and the living bone becomes strong.

  As the pore diameter of the small pores in the porous structure in the surface foam layer, the pore diameter (hereinafter referred to as the aperture diameter) opened to the surface of the surface foam layer by the measurement method using the scanning electron microscope is 10 μm or less. Preferably, the pore diameter is 5 μm or less. Similarly, the pore diameter of the large pores by the measurement method is preferably 10 to 200 μm, particularly preferably 30 to 150 μm. When the surface foamed layer has a multilayer structure having at least two kinds of pores having different sizes, the bond between the living body implant and the living bone becomes strong, but the opening diameters of the small diameter pore and the large diameter pore are within the above range. In this case, the mechanical properties of the bio-implant, particularly the surface foam layer, are not significantly reduced, and the bone-forming cells can easily enter the surface foam layer, thereby further bonding the bio-implant and the bio-bone more firmly. Can be made. In the surface foam layer, the pore diameter (hereinafter referred to as the internal diameter) formed inside the surface layer by the measuring method using a scanning electron microscope, the long diameter of the communication hole by the measuring method using the scanning electron microscope The porosity by a measuring method using a scanning electron microscope (hereinafter referred to as open porosity), the cross-sectional porosity by a measuring method using a scanning electron microscope, and the thickness of the surface foam layer are microporous. It is preferably basically the same as those in the micro surface layer of the substrate. The thickness of the surface foam layer, the opening diameter of the small-diameter pores, the internal diameter, the long diameter of the communication holes, the open porosity and the cross-sectional porosity can be adjusted basically in the same manner as the micro-surface layer. As for the opening diameter, the type and concentration of the foaming agent, the type and concentration of the foaming solution, the immersion time in the foaming solution, the type and concentration of the coagulation solution, the immersion time in the coagulation solution, the temperature in each step, etc. are selected as appropriate. It can be adjusted by doing.

The bioactive substance is immobilized without being embedded in a dispersed or scattered state on the surface of the surface foamed layer, basically in the same manner as the microporous substrate. The immobilization force of the bioactive substance particles satisfies the immobilization evaluation. Specifically, when a 200 W ultrasonic wave is irradiated for 10 minutes on a biological implant, the immobilization force is higher than that in an observation region of 100 μm ^2. The surface remains so as to remain at a surface coverage (area%) of 20% or more with respect to the surface coverage (area%) of the bioactive substance placed on the surface of the surface foam layer before irradiating with sound waves. The particles of the bioactive substance are immobilized in a state of being dispersed or scattered only on the surface of the surface foam layer of the foam substrate. The method for adjusting the immobilization force of the bioactive substance is as described above. A bioimplant in which a bioactive substance is immobilized on the surface of the surface foam layer so as to satisfy the immobilization evaluation is manufactured by, for example, a bioimplant manufacturing method according to the present invention described later.

  The method for producing a biological implant according to the present invention includes a step of heating a substrate on which a bioactive substance is arranged on a surface to a heating temperature of a glass transition temperature of a thermoplastic resin of −30 ° C. or higher and lower than a melting point, A bioimplant according to the present invention in which a bioactive substance is immobilized on the surface of a substrate so as to satisfy the evaluation can be produced. When a thermoplastic resin having such a bioactive substance disposed on its surface is heated to a heating temperature lower than its glass transition temperature of −30 ° C. or higher and lower than the melting point, a part of the surface of the thermoplastic resin softens and becomes bioactive substance. The immobilization evaluation can be satisfied when the living body implant is more firmly adhered. The method for producing a bioimplant according to the present invention can immobilize a bioactive substance in the step of heating the base material, and thus can be easily carried out without requiring an expensive or special device. The bioactive substance can be firmly fixed in a dispersed or dispersed state.

  As an example of a method for manufacturing a biological implant according to the present invention, a method for manufacturing a biological implant having a solid substrate (referred to as a manufacturing method according to the present invention) will be described below. The biological implant manufactured by the manufacturing method according to the present invention is as described above. Specifically, the solid implant is made of a thermoplastic resin and dispersed or scattered on the surface so as to satisfy the immobilization evaluation. And a bioactive substance immobilized in a state.

  In the manufacturing method according to the present invention, a solid substrate and a bioactive substance are prepared. A solid base material is produced by forming into an arbitrary shape or a desired shape by an appropriate method using the thermoplastic resin. The surface of the produced solid substrate may be adjusted with sandpaper or the like, if desired, or may be immersed or ultrasonically cleaned with pure water or the like. As the bioactive substance, a commercially available product of the bioactive substance can be used.

  In the manufacturing method according to the present invention, a step of arranging a bioactive substance on the surface of the prepared solid base material is then performed. The step of arranging may be a step of arranging the bioactive substance on the surface of the solid base material. For example, the step of spraying the bioactive substance on the surface of the solid base material, the bioactive substance forming liquid And a step of immersing the solid substrate to generate a bioactive substance on the surface of the solid substrate, a step of immersing the solid substrate in a suspension of the bioactive substance, and the like. Among these methods, even a solid substrate having a complex surface shape can be easily suspended in a state where the bioactive substance is uniformly dispersed or scattered on the complex surface. A step of immersing the solid substrate in the liquid is preferable. The step of immersing the solid substrate in the suspension of the bioactive substance includes the sub-step of preparing a suspension of the bioactive substance, if desired, in addition to the step of immersing the solid substrate. A sub-process for cleaning after removing from the substrate, a sub-process for drying the solid substrate after the cleaning, and the like.

  In order to carry out this soaking step, first, a sub-step of preparing a suspension of the bioactive substance is carried out. The medium in which the bioactive substance is suspended is not particularly limited as long as it is a medium that does not dissolve the solid base material and the bioactive substance, and examples thereof include alcohols such as methanol, ethanol, and propanol, water, acetone, and hexane. . The bioactive substance is preferably a particle having a particle diameter in the above range and the above shape. By putting the prepared bioactive substance into the medium and stirring with a stirrer or the like, if necessary, for example, irradiating ultrasonic waves with an output of 200 W at a frequency of 38 kHz, or homogenizing with an ultrasonic homogenizer, etc. The bioactive substance is uniformly suspended in the medium. The input amount of the bioactive substance at this time may be appropriately adjusted according to the surface area of the solid base material and the amount of the bioactive substance to be arranged on the surface thereof. For example, 0.01 to 100 g with respect to 100 mL of the medium It can be. Moreover, the irradiation time of ultrasonic waves is adjusted to a time during which the bioactive substance can be uniformly dispersed, and can be, for example, 5 to 180 minutes.

Next, a step of immersing the prepared solid base material in the suspension thus prepared is performed. This dipping step is carried out by dipping the solid substrate in the suspension and stirring the suspension as desired. The liquid temperature of the suspension at this time, that is, the immersion temperature and the immersion time are not particularly limited, and may be appropriately adjusted according to the amount of the bioactive substance disposed on the surface of the solid substrate. The glass transition temperature of the thermoplastic resin forming the solid substrate is less than −30 ° C., specifically the temperature below the boiling point of the solvent, and the immersion time can be 1 minute or more and 24 hours or less. The volume of the solid substrate immersed in the suspension is not particularly limited, but the amount of the bioactive substance to be disposed may be reduced if the amount of the suspension is not sufficient. On the other hand, it can be set to 0.001 to 50 cm ³ .

  In the step of immersing, if desired, a sub-step of washing after removing the solid substrate from the suspension is performed. The cleaning liquid for cleaning the solid base material is not particularly limited as long as it is a medium that does not dissolve the solid base material and the bioactive substance, and examples thereof include water, the same medium as the suspension medium, and water or pure water. Preferably there is. In the step of immersing, if desired, a sub-step of drying the solid substrate after cleaning is performed. As the drying method, a known drying method can be adopted without any particular limitation, and examples thereof include air drying, air drying, and heat drying. The heating temperature for heating in the drying sub-process is lower than the glass transition temperature of the thermoplastic resin forming the solid substrate.

  In this way, the step of immersing the solid substrate in the suspension of the bioactive substance is performed. In this dipping process, the bioactive substance disposed on the surface of the solid substrate adheres to the surface of the solid substrate, and most of the solid substrate is also in the cleaning sub-process and the drying sub-process. Do not fall off the surface.

  In the manufacturing method according to the present invention, after the placing step thus performed, the solid substrate on which the bioactive substance is placed on the surface has a glass transition temperature of −30 ° C. or higher and lower than the melting point of the thermoplastic resin. A step of heating to a heating temperature is performed. The heating temperature of the solid substrate is not less than the glass transition temperature (Tg) -30 ° C. of the thermoplastic resin forming the solid substrate, that is, 30 ° C. lower than the glass transition temperature (Tg-30) ° C. It is less than the melting point of the thermoplastic resin. When the solid substrate is heated to this temperature range, a portion of the solid substrate near the surface softens and adheres firmly to the bioactive substance disposed. The lower limit of the heating temperature is (Tg-30) ° C., and it is preferably not less than the glass transition temperature (Tg) in that the solid substrate and the bioactive substance can be more firmly adhered to each other. It is particularly preferable that the transition temperature (Tg) + 40 ° C., and the upper limit of the heating temperature is less than the melting point of the thermoplastic resin, so that the solid substrate and the bioactive substance can be more firmly adhered to each other. The transition temperature (Tg) is preferably 80 ° C. In the present invention, the glass transition temperature (Tg) of the thermoplastic resin is the lowest glass transition temperature when the thermoplastic resin has a plurality of glass transition temperatures.

  In this heating step, the time for heating the solid substrate, that is, the time for maintaining the heating temperature may be any time that can soften the vicinity of the surface of the solid substrate. Is more preferably 1 hour or more, and particularly preferably 3 hours or more, in that it can be more firmly adhered. The upper limit value of the heating time is not particularly limited, and even if it is considerably long, improvement in the degree of adhesion of the bioactive substance to the base material cannot be expected. be able to. A known heating method can be appropriately employed as the method for heating the solid substrate. In this way, the bioactive substance disposed on the surface of the solid substrate can be immobilized.

  Thus, the solid base material on which the bioactive substance is immobilized can be used as it is, or can be used after being molded or shaped into a desired shape. When the solid base material on which the bioactive substance is immobilized is used as it is, it is preferably molded into a desired shape at the time of preparation of the solid base material, and the bioactive substance obtained by the heating step is The fixed solid base material becomes a biological implant. On the other hand, when the solid substrate obtained by the heating step and having the bioactive substance immobilized thereon is molded, the molded body obtained by molding becomes a biological implant. In the present invention, since there is a concern that the immobilized bioactive substance may fall off, it is preferable to use the solid base material on which the bioactive substance is immobilized as it is.

  In the manufacturing method according to the present invention, the step of shaping or shaping the outer shape into a desired shape is preferably performed after the bioactive substance is immobilized, and at the time of preparing the solid base material. This molding step is performed by a known molding method or the like to form a solid base material on which a thermoplastic resin or a bioactive substance is immobilized in a shape suitable for an application site in a living body, a particulate shape, a fiber shape, a block shape, Molded into a film or the like. The shape suitable for the application site in the living body is specifically the same shape as the shape of the bone defect part or the tooth defect part, the shape corresponding to the shape of the bone defect part or the tooth defect part, for example, a similar shape Etc.

  In this way, the manufacturing method according to the present invention is performed, and a biological implant having a solid substrate is manufactured.

  As another example of the method for manufacturing a biological implant according to the present invention, a method for manufacturing a biological implant having a multilayer substrate (referred to as another manufacturing method according to the present invention) will be described below. The biological implant produced by another production method according to the present invention is as described above. Specifically, the biological implant is formed on the surface of a multilayer substrate having a substantial part and a surface layer made of a thermoplastic resin and the surface layer. And a bioactive substance immobilized in a dispersed or scattered state so as to satisfy the immobilization evaluation.

  Another manufacturing method according to the present invention is the same as the manufacturing method according to the present invention except that the step of forming the surface layer is performed before the step of disposing the bioactive substance on the surface of the surface layer of the multilayer substrate. Basically the same. Therefore, in another manufacturing method according to the present invention, a multilayer substrate and a bioactive substance are prepared.

  For example, when preparing a microporous substrate, as a step of forming a micro surface layer, for example, (1) a solid substrate formed of a thermoplastic resin is corrosive with concentrated sulfuric acid, concentrated nitric acid, chromic acid, or the like. (2) a low molecular water-soluble organic substance such as sucrose or a low molecular water-soluble inorganic substance such as sodium chloride dispersed in a thermoplastic resin and melt-molded; A step of immersing in a solvent such as water from which a low-molecular water-soluble organic substance or a low-molecular water-soluble inorganic substance elutes for a predetermined time; (3) a step of using a foaming agent together with the thermoplastic resin; and (4) particles of the thermoplastic resin. Well-known processes, such as the process of forming the porous body by welding the surface of, are mentioned. A microporous substrate having a substantial part and a microsurface layer is produced by any of these steps. Therefore, the step of forming the micro surface layer is also a step of preparing a micro porous substrate having a substantial part and a micro surface layer, that is, a micro porous substrate having a micro surface layer having a porous structure with a thermoplastic resin. it can.

  On the other hand, when preparing a surface foam base material, as a step of forming the surface foam layer, for example, (5) a solid base material formed of a thermoplastic resin is corrosive such as concentrated sulfuric acid, concentrated nitric acid, chromic acid or the like. A known process such as a process of immersing in a foaming solution after being immersed in a foaming agent after being immersed in the solution can be used. By this step, a surface foamed substrate having a substantial part and a surface foamed layer is produced. Therefore, the step of forming the surface foamed layer is a step of producing a surface foamed base material having a substantial part and a surface foamed layer, that is, a surface foamed base material having a surface foamed layer having a porous structure with a thermoplastic resin. it can. Said (1) and (5) are fundamentally the same as the method described in the international publication 2009/095960 pamphlet etc., for example. Specifically, the step (5) is a sub-step 1 in which a solid substrate formed of a thermoplastic resin is immersed in a corrosive solution to form small-diameter pores, thereby obtaining a micro-porous substrate. (Corresponding to the step (1)), and the microporous substrate (also referred to as a microporous substrate) obtained in the sub-step 1 is dipped in a solution containing a foaming agent, thereby maintaining the foaming agent-holding substrate. Sub-step 2 to obtain a foamed base material by immersing the foaming agent holding base material obtained in the sub-step 2 in a foaming solution that swells the plastic and foams the foaming agent; and And sub-step 4 of immersing the foamed base material obtained in sub-step 3 in a coagulation solution for coagulating the swollen plastic. In addition, this multilayer base material may be produced through the process of shape | molding similarly to a solid base material, the process of adjusting a surface, and the process of wash | cleaning.

  In another manufacturing method according to the present invention, a step of arranging a bioactive substance on the surface of the prepared multilayer base material is then performed. The step of arranging is basically the same as the step of arranging in the manufacturing method according to the present invention. In another manufacturing method according to the present invention, instead of the preferable “step of immersing the solid base material in the suspension of the bioactive substance”, the “solid base material is immersed in the bioactive substance forming liquid”. The step of generating a bioactive substance on the surface of the solid substrate will be described. As a preferable example of the step of generating, a step of immersing a multilayer base material having a surface layer in either a solution containing at least 10 mM calcium ions or a solution containing at least 10 mM phosphate ions is given first. It is done. In the present invention, since the heating step described above is carried out, the lower limit of the calcium ion and phosphate ion concentration should be a low concentration of about 10 mM so long as they are precipitated on the surface of the substrate. Can do. Note that this generating step can also be applied to a solid substrate.

  In this generating step, the order in which the multilayer base material is immersed in two types of solutions is not particularly limited. For example, when hydroxyapatite is generated as a bioactive substance in the surface layer, the solubility of hydroxyapatite is low. It is preferable that the production reaction proceeds in a lower alkaline region from the viewpoint of the amount of production, and therefore, the pH of the solution immersed in the latter half is preferably an alkaline region of pH 8-10. Therefore, in the step of generating, after performing the Ca immersion sub-step of immersing the multilayer substrate in a solution containing at least 10 mM calcium ions for a predetermined time, the multilayer substrate is converted into a solution containing at least 10 mM phosphate ions. It is preferable to perform the P-immersion sub-step of immersing.

  In this generated process, a Ca immersion sub-process is performed in which the multilayer substrate is immersed in a solution containing at least 10 mM calcium ions for a predetermined time. The solution containing calcium ions only needs to contain at least calcium ions, and includes sodium ions, potassium ions, magnesium ions, carbonate ions, silicate ions, sulfate ions, nitrate ions, chloride ions, hydrogen ions, and the like. However, it is preferable that the phosphate ion is not substantially contained. Examples of the solution containing calcium ions usually include an aqueous solution of a calcium compound that is highly water-soluble and does not adversely affect the human body. For example, calcium chloride, calcium hydroxide, calcium nitrate, calcium formate, calcium acetate, propionic acid Examples of the aqueous solution include calcium, calcium butyrate, calcium lactate, and a mixture thereof, and an aqueous solution of calcium chloride is preferable.

  In this generation step, a P-immersion sub-step is then performed in which the multilayer substrate is immersed in a solution containing at least 10 mM phosphate ions. The solution containing phosphate ions may contain at least phosphate ions, including sodium ions, potassium ions, magnesium ions, carbonate ions, silicate ions, sulfate ions, nitrate ions, chloride ions, hydrogen ions, and the like. However, it is preferable that calcium ions are not substantially contained. Examples of the solution containing phosphate ions include an aqueous solution of a phosphate compound that is highly water-soluble and does not adversely affect the human body. For example, phosphoric acid, disodium hydrogen phosphate, sodium dihydrogen phosphate, phosphorus Examples include aqueous solutions of dipotassium hydrogen hydrogen, potassium dihydrogen phosphate, and mixtures thereof, and aqueous solutions of dipotassium hydrogen phosphate are preferable.

In the Ca immersion sub-process and the P immersion sub-process, the immersion time is preferably 1 minute to 5 hours, and particularly preferably 3 minutes to 3 hours. When the immersion time is in the range of 1 minute to 5 hours, the calcium ions or phosphate ions are sufficiently infiltrated into the surface layer, and the bioactive substance is sufficiently generated, so that the bioactive substance is firmly formed in the surface layer. To be fixed. In the Ca immersion sub-process and the P immersion sub-process, the immersion temperature is preferably set to less than −30 ° C., specifically 10 to 50 ° C. of the thermoplastic resin forming the multilayer substrate. The volume of the multilayer substrate to be formed can be 0.01 to 20 cm ³ with respect to 100 mL of these solutions.

  In the step of generating, a sub-step of immersing and cleaning the multilayer base material on which the bioactive substance is disposed in pure water while irradiating with ultrasonic waves, a sub-step of drying, and the like can be performed.

  When the Ca immersion sub-process and the P immersion sub-process are performed in this way, the bioactive substance adheres to the surface of all the portions having the porous structure of the surface layer of the multilayer substrate or the portion having the porous structure. Even when the sub-step of generating and cleaning and the sub-step of drying are performed, most of them do not fall off from the surface of the multilayer substrate. In this way, the bioactive substance can be disposed on the surface of the surface layer in the multilayer substrate. The bioactive compound produced in this “generating step” is a low crystalline bioactive compound that satisfies the above conditions.

  In another manufacturing method according to the present invention, following the step of placing as described above, the multilayer substrate on which the bioactive substance is placed on the surface is melted at a glass transition temperature of −30 ° C. or higher of the thermoplastic resin. A step of heating to a heating temperature of less than is performed. This heating step is performed basically in the same manner as the heating step in the manufacturing method according to the present invention. Note that the porous structure is not destroyed even in the step of heating the surface layer. In this way, the bioactive substance disposed on the surface of the multilayer substrate can be immobilized.

  The multilayer base material on which the bioactive substance is immobilized in this manner can be used as it is, as with the solid base material, or can be used after being molded or shaped into a desired shape. . Therefore, the process of shaping or shaping the outer shape into a desired shape in another manufacturing method according to the present invention is basically the same as the process of shaping or shaping the outer shape into a desired shape according to the present invention. In another manufacturing method according to the present invention, the surface layer can be formed after forming, shaping and / or preparing the solid substrate in a desired shape, or the desired shape can be formed after forming the surface layer on the solid substrate. It can also be shaped, shaped and / or prepared.

  In this way, another manufacturing method according to the present invention is performed, and a biological implant having a multilayer substrate is manufactured.

  The living body implant and the manufacturing method of the living body implant according to the present invention are not limited to the above-described examples, and various modifications can be made as long as the object of the present invention can be achieved.

Example 1
The surface of a disc body (diameter 10 mm, thickness 2 mm, Victrex 450 G) formed of polyether ether ketone (glass transition temperature 143 ° C., melting point 340 ° C., elastic modulus 4.2 GPa, flexural strength 170 MPa) is sandpaper (# 4000), and then immersed in pure water and washed by ultrasonic irradiation to prepare a solid substrate. In addition, ethanol (200 mL) and HAP (hydroxyapatite) (Taihei Chemical Co., Ltd., HAP-200, particle shape: columnar, particle size 0.1 to 1 μm (intercept method), half width 0.2 °) 3.0 g And treated with a homogenizer with a frequency of 20 kHz and an output of 200 W for 10 minutes to disperse the hydroxyapatite particles in ethanol to prepare an ethanol suspension.

  The solid substrate was put into 200 mL of the prepared ethanol suspension and stirred vigorously for 1 hour, and then the solid substrate was taken out of the ethanol suspension and washed with pure water. The solid substrate was heated at 220 ° C. for 3 hours and then cooled to room temperature to produce the biological implant of Example 1. The hydroxyapatite particles immobilized on the biological implant maintained the particle shape, particle diameter and half-value width of the particles used.

(Example 2)
A biological implant of Example 2 was produced in the same manner as Example 1 except that the heating temperature of the solid substrate was changed to 180 ° C.

(Example 3)
A biological implant of Example 3 was produced in the same manner as in Example 1 except that the heating time of the solid substrate was changed to 1 hour.

Example 4
A biological implant of Example 4 was produced in the same manner as in Example 1 except that the heating time of the solid substrate was changed to 24 hours.

(Example 5)
As calcium apatite particles, calcium hydrogen phosphate dihydrate (manufactured by Kanto Chemical Co., Ltd.) and calcium carbonate (manufactured by Kishida Chemical Co., Ltd.) are adjusted to a Ca / P ratio of 1.67 and pulverized and mixed in water using a pot. And then calcined at 900 ° C. (Mechanochemical synthesis method) Hydroxyapatite particles (particle shape: spherical, particle diameter 0.05 to 0.5 μm, half width 0.17) were used. A biological implant of Example 5 was produced in the same manner as Example 1 except that.

(Example 6)
A biological implant of Example 6 was produced in the same manner as Example 5 except that the heating temperature of the substrate was 120 ° C.

(Example 7)
The biological implant of Example 7 was obtained in the same manner as in Example 5 except that a surface foamed base material (indicated as “foaming” in Table 1) prepared by the following method was used instead of the solid base material. Manufactured.

<Preparation of surface foam substrate>
The surface of a disk body (diameter 10 mm, thickness 2 mm, Victrex 450G) formed of PEEK was polished with sandpaper (# 1000) and immersed in concentrated sulfuric acid (concentration: 97%) for 5 minutes. The disc body pulled up from the concentrated sulfuric acid was immersed in pure water for 5 minutes, and then repeatedly washed until the pH of the pure water became neutral to obtain a microporous substrate having a microsurface layer with a porous structure (sub-process) 1). When the surface of this micro surface layer was observed with a scanning electron microscope, it had a large number of pores, the pore diameter of these pores was 1 to 2 μm, and the inside was a network structure.

  Next, this microporous substrate was immersed in an aqueous potassium carbonate solution (concentration: 3M) for 60 minutes, whereby potassium carbonate was retained on the surface of the micro surface layer to obtain a foaming agent retaining substrate (Sub-step 2). By immersing this foaming agent holding substrate in concentrated sulfuric acid (concentration: 97%) as a foaming solution for 1 minute, the surface of PEEK in the foaming agent holding substrate is swollen and at the same time potassium carbonate in the foaming agent holding substrate Was foamed to obtain a foamed substrate (sub-process 3).

  The foam base was lifted from concentrated sulfuric acid and immersed in sulfuric acid having a concentration of 86% for 5 minutes. Next, the surface of PEEK is solidified by lifting the foamed substrate from sulfuric acid and immersing in pure water for 10 minutes (sub-process 4), and after repeatedly washing the pure water until the pH becomes neutral, at 80 ° C. The surface foamed substrate was obtained by drying for 3 hours. Scanning electron micrographs obtained by photographing the surface of the obtained surface foamed substrate at a low magnification of 300 times and a high magnification of 10000 times are shown in FIGS. 22 and 23, respectively.

  Using each photograph taken at a magnification of 300 times, the major and minor diameters of the large pores were measured as described above, and the arithmetic average of these measured values was calculated. The average pore diameter of the large pores Was 92 μm.

  By using the image analysis software (Scion Image, manufactured by Scion) to binarize the photograph of the surface foam surface with a scanning electron microscope, it is binarized into a large-diameter pore and other parts. The area ratio of large pores having a pore diameter of 10 to 200 μm to the area was calculated to be 65%.

(Example 8)
Particles obtained by synthesizing mechanochemical synthesis and calcining at 700 ° C. as the hydroxyapatite particles (particle shape: spherical, particle diameter of 0.01 to 0.1 μm, half width of 0.26) ) Was used in the same manner as in Example 7 except that a biological implant of Example 8 was produced.

Example 9
As the hydroxyapatite particles, particles obtained by mechanochemical synthesis and calcined at 1100 ° C. (particle shape: spherical, particle diameter 0.1 to 5 μm, half width 0.15) are obtained. A biological implant of Example 9 was produced in the same manner as Example 7 except that it was used.

(Example 10)
A biological implant of Example 10 was produced in the same manner as in Example 5 except that the microporous substrate produced in Example 7 was used.

(Comparative Example 1)
A biological implant of Comparative Example 1 was produced in the same manner as in Example 1 except that the heating temperature of the solid substrate was changed to 80 ° C.

(Comparative Example 2)
A biological implant of Comparative Example 2 was produced in the same manner as in Example 5 except that the heating temperature of the solid substrate was changed to 80 ° C.

(Surface observation of biological implants)
In Example 1, the scanning electron micrograph when the surface of the solid substrate after washing with pure water is observed with a scanning electron microscope (magnification: 3000 and 10,000 times) is shown in FIG. In FIG. 1, the white portion is hydroxyapatite. As shown in FIG. 1, it was found that the hydroxyapatite adhered to the surface of the solid base material even when immersed in an ethanol suspension and washed with pure water.

  Scanning electron micrographs obtained by observing the surfaces of the biological implants produced in Examples 1, 2, 5 to 9 and Comparative Examples 1 and 2 with a scanning electron microscope (magnification rate of 10,000 times) are shown in FIG. 4, 6, 8, 10, 12 and 14, and FIGS. 17 and 19. In these drawings, the white portion is hydroxyapatite.

  The biological implants of Examples 1 and 2 and Comparative Example 1 were found to have hydroxyapatite attached to their surfaces as shown in FIGS. 2, 4 and 17. Examples 5 and 6 using “hydroxyapatite obtained by calcining at 900 ° C. (mechanochemical synthesis, calcining at 900 ° C.)” instead of HAP-200 in Example 1 or the like as hydroxyapatite. In addition, as shown in FIGS. 6, 8, and 19, the biological implant of Comparative Example 2 was found to have hydroxyapatite attached to the surface thereof. Furthermore, the biological implants of Examples 7 to 9 using a surface foamed base material instead of the solid base material of Example 1 or the like as the base material also have the surface thereof as shown in FIGS. It was found that hydroxyapatite was attached to the surface of the foamed substrate.

(Coverage before irradiation)
For each of the biological implants produced in Examples 1 to 10 and Comparative Examples 1 and 2, the coverage (area%) before irradiation with hydroxyapatite was as described above with three observation areas (100 μm ² ) on the surface. It calculated using the microscope picture image | photographed in this, and obtained the arithmetic mean value of these 3 points | pieces. The results are shown in Table 1 as “coverage (%) before irradiation”.

(Coverage after irradiation)
Each of the living body implants manufactured in Examples 1 to 10 and Comparative Examples 1 and 2 was irradiated with ultrasonic waves having a frequency of 38 kHz and an output of 200 W in water for 10 minutes, and the coverage (area%) with hydroxyapatite was as described above. The arithmetic average value of these three points was obtained. The results are shown in Table 1 as “coverage (%) after irradiation”. Scanning electron micrographs after ultrasonic irradiation of Examples 1, 2, 5 to 10 and Comparative Examples 1 and 2 taken when calculating the coverage (area%) after irradiation in this way, 3, 5, 7, 9, 11, 13, 13, 15, 16, 18, and 20. In these drawings, the white portion is hydroxyapatite.

(Evaluation of immobilization of hydroxyapatite)
As the fixing power of hydroxyapatite by the immobilization evaluation, a value (%) obtained by dividing the coverage (area%) after irradiation calculated as described above by the coverage (area%) before irradiation is calculated. Table 1 shows the “residual rate (%)”.

  As a result, as shown in Table 1, in the biological implants of Examples 1 to 10, the “residual rate (%)” of hydroxyapatite exceeded 20%. In particular, the biological implants of Examples 1 to 3 had a “residual rate (%)” of hydroxyapatite greatly exceeding 20% as shown in Table 1 and, for example, FIGS. 3 and 5. 2 and 3 in Example 1 and FIGS. 4 and 5 in Example 2 are compared with each other, in each Example, the water disposed on the surface of the solid base material before and after ultrasonic irradiation. The number of acid apatites did not change significantly. As described above, the biological implants of Examples 1 to 3 can be confirmed that the hydroxyapatite is firmly fixed on the surface of the solid base material, and sufficiently exhibit high binding ability with the living bone. Guessed.

  On the other hand, the biological implant of Comparative Example 1 had a “residual rate (%)” of hydroxyapatite of less than 20%, as shown in Table 1 and FIG. Moreover, when comparing FIG. 17 and FIG. 18 in Comparative Example 1, the hydroxyapatite disposed on the surface of the solid base material is greatly reduced, and the hydroxyapatite is immobilized on the surface of the solid base material. I knew that it was missing.

  Moreover, it replaces with HAP-200 (it is described as "HAP1" in Table 1) of Example 1 etc.) as a hydroxyapatite "Hydroxyapatite obtained by calcining at 900 ° C (mechanochemical synthesis) , 900 ° C. calcination) ”(denoted as“ HAP2 ”in Table 1), the biological implants of Examples 5 and 6 are also shown in Table 1 and FIGS. The “residual rate (%)” of hydroxyapatite greatly exceeded 20%. Furthermore, when FIGS. 6 and 7 in Example 5 and FIGS. 8 and 9 in Example 7 are respectively compared, in each Example, the water disposed on the surface of the solid base material before and after ultrasonic irradiation. The number of acid apatites did not change significantly. Thus, even if the kind of hydroxyapatite is changed in this way, the bioimplants of the present invention, specifically, the bioimplants of Examples 5 and 6, have hydroxyapatite firmly attached to the surface of the solid substrate. It can be confirmed that it is immobilized, and it is sufficiently speculated that it exhibits a high binding ability with living bone.

  On the other hand, as shown in Table 1 and FIG. 20, in the biological implant of Comparative Example 2, the “residual rate (%)” of hydroxyapatite did not reach 20%. Further, when comparing FIG. 19 and FIG. 20 in Comparative Example 2, the hydroxyapatite arranged on the surface of the solid base material is greatly reduced, and the hydroxyapatite is immobilized on the surface of the solid base material. I knew that it was missing.

  Furthermore, the biological implants of Examples 7 to 9 using a surface foamed substrate instead of the solid substrate of Example 1 as the substrate and the biological implant of Example 10 using a microporous substrate are also the first. As shown in the table and FIGS. 11, 13, 15, and 16, the “residual rate (%)” of hydroxyapatite greatly exceeded 20%. Further, FIGS. 10 and 11 in Example 7, FIGS. 12 and 13 in Example 8, and FIGS. 14 and 15 in Example 9 are compared, and in each Example, the surface before and after the ultrasonic irradiation The number of hydroxyapatites arranged on the surface of the foamed substrate did not change greatly. Thus, even if the type of the substrate is replaced with a surface foamed substrate or a microporous substrate, the biological implant of the present invention, specifically, the biological implants of Examples 7 to 10, It can be confirmed that the hydroxyapatite is firmly fixed on the surface of the surface foamed base material and the microporous base material, and it is sufficiently presumed that the hydroxyapatite exhibits high binding ability with living bone.

(Hydroxyapatite fixed state)
The living body implant produced in Example 1 was filled with resin and then subjected to CP processing to expose a fresh section, and this fresh section was observed with a scanning electron microscope (magnification rate: 10,000 times). A scanning electron micrograph at this time is shown in FIG. In FIG. 21, the white portion is hydroxyapatite. As a result, it was confirmed that the hydroxyapatite particles fixed on the solid base material were not embedded in the solid base material but adhered to the surface, and most of the particles were exposed.

  The biological implant according to the present invention can be applied to a portion where the mechanical properties of the base material are not impaired and a load is applied, and the bioactive substance is not easily detached from the base material and is highly resistant to a living bone. Because it exhibits binding ability, it is a medical member for treating a defect part where bone has been lost, particularly a defect part under load, such as a bone filling material, an artificial joint member, an osteosynthesis material, an artificial vertebral body, an interbody spacer It can be suitably used as a vertebral body cage and an artificial tooth root.

  The bioimplant manufacturing method according to the present invention is a simple method that does not require an expensive or special device, but the bioactive substance is firmly fixed in a dispersed or scattered state on the surface of the substrate. Therefore, it can be suitably used for the production of the biological implant according to the present invention.

Claims (10)

A bioimplant manufacturing method for manufacturing a bioimplant in which a bioactive substance is immobilized on the surface of a base material made of a thermoplastic resin,
A method for producing a biological implant, comprising a step of heating a base material on which the bioactive substance is disposed on a surface to a heating temperature of a glass transition temperature of -30 ° C or higher and lower than a melting point of the thermoplastic resin.   The method for producing a living body implant according to claim 1, wherein the heating temperature is equal to or higher than a glass transition temperature of the thermoplastic resin and lower than a melting point.   The method of manufacturing a biological implant according to claim 1 or 2, wherein the heating step is a step of heating the base material at the heating temperature for 1 hour or more. Arranging the bioactive substance on the surface of the substrate;
The method for producing a biological implant according to any one of claims 1 to 3, wherein the arranging step includes a step of immersing the base material in a suspension of a bioactive substance.   The method for producing a biological implant according to any one of claims 1 to 4, further comprising a step of producing a base material having a surface layer having a porous structure with a thermoplastic resin. The said thermoplastic resin is an engineering plastic, The manufacturing method of the biological implant of any one of Claims 1-5 characterized by the above-mentioned. The method of manufacturing a biological implant according to claim 6 , wherein the engineering plastic is polyetheretherketone. The bioactive agent, method for producing an implant according to any one of 請 Motomeko 1-7 you characterized in that at least one of calcium phosphate compounds and bioactive glass. The method for producing a biological implant according to claim 8 , wherein the calcium phosphate compound is hydroxyapatite. The method for producing a biological implant according to claim 8 , wherein the calcium phosphate compound is tricalcium phosphate.

Images